Screw compressor and air conditioner

Abstract

The invention provides a screw compressor and an air conditioner, the screw compressor comprises a plurality of rotor pairs, and each rotor pair comprises a second-stage first rotor pair, a second-stage second rotor pair, a first-stage first rotor pair, a first-stage second rotor pair, a second-stage third rotor pair and a second-stage fourth rotor pair which are arranged in sequence; the second-stage first rotor pair and the second-stage second rotor pair are symmetrically arranged, the first-stage first rotor pair and the first-stage second rotor pair are symmetrically arranged, and the second-stage third rotor pair and the second-stage fourth rotor pair are symmetrically arranged; each rotor pair sucks air from one side of the respective meshing position and exhausts air from the other side of the respective meshing position; the air suction sides of the first-stage first rotor pair and the first-stage second rotor pair are opposite to the air suction sides of the second-stage first rotor pair, the second-stage second rotor pair, the second-stage third rotor pair and the second-stage fourth rotor pair. According to the technical scheme, the balance of the radial gas force of the rotor can be improved while the balance of the axial gas force of the rotor is ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of compressors, and in particular relates to a screw compressor and an air conditioner. Background Art

[0002] When the oil-injected screw compressor compresses the medium gas, the rotor of the screw compressor itself is also subjected to the reaction force of the medium gas. When analyzing the gas force on the rotor, the gas force is usually decomposed into axial gas force and radial gas force, and then the corresponding load-bearing structure and scheme are made respectively. Generally speaking, the final carrier of axial gas force and radial gas force is the bearing. The life of the bearing is directly related to the service life of the screw compressor. Overloading of a single bearing will cause a cliff-like decline in the life of the bearing. At the same time, there is also a minimum load requirement for the rolling bearing to ensure that the bearing rolling element rolls normally instead of sliding, otherwise it will also cause damage to the bearing. Therefore, after determining the force on the rotor, the bearing model and quantity will be selected according to the values ​​of the axial gas force and radial gas force to avoid overloading the bearing. Under some harsh working conditions, due to the large rotor gas force, the size and number of the selected bearings will also increase, but when the working conditions change, the rotor gas force may drop significantly for a certain period of time, or even fall below the minimum load required by the bearing, causing bearing damage. At the same time, the increase in the size and number of bearings is also unfavorable to the size, weight and cost of the compressor.

[0003] The best solution for sharing the bearing load is to offset the rotor gas force at the source. In the existing related technical solutions, two pairs of rotors of the same size and opposite directions can be used. During the operation, no matter how large the gas force is, the axial gas force will always be offset and balanced, making the axial gas force very small and stable. Only a single small-load bearing is needed to meet the requirements, simplifying the structure, improving reliability, and reducing costs. However, the radial gas force is not completely offset, and the radial gas force still has the problem of large load and large variation. Summary of the invention

[0004] Therefore, the present invention provides a screw compressor and an air conditioner, the main technical problem to be solved is: how to improve the balance of the radial gas force of the rotor while ensuring the balance of the axial gas force of the rotor.

[0005] In order to solve the above problems, the present invention provides a screw compressor, which includes a plurality of rotor pairs, each of which has a pair of mutually meshing male and female rotors, the male rotors of each rotor pair are coaxially arranged, and the female rotors of each rotor pair are coaxially arranged;

[0006] Among them, each of the rotor pairs is a second-stage first rotor pair, a second-stage second rotor pair, a first-stage first rotor pair, a first-stage second rotor pair, a second-stage third rotor pair, and a second-stage fourth rotor pair; the second-stage first rotor pair and the second-stage second rotor pair are symmetrically arranged, the first-stage first rotor pair and the first-stage second rotor pair are symmetrically arranged, and the second-stage third rotor pair and the second-stage fourth rotor pair are symmetrically arranged;

[0007] Each of the rotor pairs sucks air from one side of its meshing position and exhausts air from the other side of its meshing position; and the suction sides of the first-stage first rotor pair and the first-stage second rotor pair are opposite to the suction sides of the second-stage first rotor pair, the second-stage second rotor pair, the second-stage third rotor pair, and the second-stage fourth rotor pair.

[0008] In some embodiments, the radial resultant forces on the first-stage first rotor pair and the first-stage second rotor pair are both F 合1 , and the radial resultant forces on the second-stage first rotor pair, the second-stage second rotor pair, the second-stage third rotor pair, and the second-stage fourth rotor pair are all F 合2 ;

[0009] wherein, F 合1 and F 合2 are equal in magnitude and opposite in direction.

[0010] In some embodiments, the second-stage first rotor pair and the second-stage fourth rotor pair are symmetrically arranged; and the radial resultant force on the male rotor of the first-stage first rotor pair is F1, the radial resultant force on the female rotor of the first-stage first rotor pair is F2, the radial resultant force on the male rotor of the second-stage first rotor pair is F4, and the radial resultant force on the female rotor of the second-stage first rotor pair is F3;

[0011] wherein, F1 and F3 are opposite in direction, and F1 = 2 * F3; F2 and F4 are opposite in direction, and F2 = 2 * F4.

[0012] In some embodiments, the end face profiles of the rotors within the first-stage first rotor pair and the first-stage second rotor pair are the same and are both the first end face profile; the end face profiles of the rotors within the second-stage first rotor pair, the second-stage second rotor pair, the second-stage third rotor pair, and the second-stage fourth rotor pair are the same and are both the second end face profile;

[0013] The first end face profile and the second end face profile are in a proportional scaling relationship.

[0014] In some embodiments, the suction sides of the second-stage first rotor pair, the second-stage second rotor pair, the second-stage third rotor pair, and the second-stage fourth rotor pair are all configured to suck air from the exhaust sides of both the first-stage first rotor pair and the first-stage second rotor pair.

[0015] In some embodiments, the second-stage first rotor pair, the second-stage second rotor pair, the first-stage first rotor pair, the first-stage second rotor pair, the second-stage third rotor pair, and the second-stage fourth rotor pair are arranged in sequence along a first direction, which is the axial direction of the shafts where the male rotors of each rotor pair are located.

[0016] In some embodiments, the screw compressor further includes a housing, which has a first compression chamber, a second compression chamber, and a third compression chamber separated from each other; the second-stage first rotor pair and the second-stage second rotor pair are both arranged in the first compression chamber, the first-stage first rotor pair and the first-stage second rotor pair are both arranged in the second compression chamber, and the second-stage third rotor pair and the second-stage fourth rotor pair are both arranged in the third compression chamber;

[0017] Wherein, a first flow channel is provided inside the housing, and the first flow channel has a first air passage port, a second air passage port, a third air passage port, a fourth air passage port, and a fifth air passage port; both the first air passage port and the second air passage port are in communication with the first compression chamber, and the suction side of the second-stage first rotor pair sucks air through the first air passage port, and the suction side of the second-stage second rotor pair sucks air through the second air passage port; both the third air passage port and the fourth air passage port are in communication with the third compression chamber, and the suction side of the second-stage third rotor pair sucks air through the third air passage port, and the suction side of the second-stage fourth rotor pair sucks air through the fourth air passage port; the fifth air passage port is in communication with the second compression chamber, and the exhaust sides of both the first-stage first rotor pair and the first-stage second rotor pair exhaust air through the fifth air passage port.

[0018] In some embodiments, the first flow channel is symmetrically arranged with respect to the mid-plane of both the first-stage first rotor pair and the first-stage second rotor pair.

[0019] In some embodiments, when the screw compressor includes a housing, and the housing has a first compression chamber, a second compression chamber, and a third compression chamber separated from each other; the second-stage first rotor pair and the second-stage second rotor pair are both arranged in the first compression chamber, the first-stage first rotor pair and the first-stage second rotor pair are both arranged in the second compression chamber, and the second-stage third rotor pair and the second-stage fourth rotor pair are both arranged in the third compression chamber,

[0020] The first compression chamber has a first exhaust port. The exhaust sides of both the second-stage first rotor pair and the second-stage second rotor pair exhaust through the first exhaust port. The third compression chamber has a second exhaust port. The exhaust sides of both the second-stage third rotor pair and the second-stage fourth rotor pair exhaust through the second exhaust port. The first exhaust port and the second exhaust port are symmetrically arranged with respect to the middle plane of both the first-stage first rotor pair and the first-stage second rotor pair;

[0021] And / or, a second flow path is provided in the machine body. The second flow path has a second A air passage port, a second B air passage port, and a second C air passage port. Both the second B air passage port and the second C air passage port communicate with the second compression chamber. The suction side of the first-stage first rotor pair sucks air through the second B air passage port, and the suction side of the first-stage second rotor pair sucks air through the second C air passage port. The second A air passage port penetrates through the outer wall of the machine body; The second flow path is symmetrically arranged with respect to the middle plane of both the first-stage first rotor pair and the first-stage second rotor pair.

[0022] In some embodiments, a first bearing is sleeved on the shaft section between the male rotors of the second-stage second rotor pair and the first-stage first rotor pair, and a second bearing is sleeved on the shaft section between the female rotors of the two; A third bearing is sleeved on the shaft section between the male rotors of the second-stage third rotor pair and the first-stage second rotor pair, and a fourth bearing is sleeved on the shaft section between the female rotors of the two;

[0023] And / or, fifth bearings are provided at both ends of the rotating shaft where the male rotor of each rotor pair is located, and sixth bearings are provided at both ends of the rotating shaft where the female rotor of each rotor pair is located.

[0024] The present invention also provides an air conditioner, which may include the screw compressor described in any one of the above.

[0025] A screw compressor and an air conditioner provided by the present invention have the following beneficial effects:

[0026] 1. In the present invention, the suction sides of both the first-stage first rotor pair and the first-stage second rotor pair are opposite to the suction sides of the four rotor pairs including the second-stage first rotor pair, the second-stage second rotor pair, the second-stage third rotor pair, and the second-stage fourth rotor pair. Also, the discharge sides of both the first-stage first rotor pair and the first-stage second rotor pair are opposite to the discharge sides of the four rotor pairs including the second-stage first rotor pair, the second-stage second rotor pair, the second-stage third rotor pair, and the second-stage fourth rotor pair. As a result, the radial gas forces on both the first-stage first rotor pair and the first-stage second rotor pair are in opposite directions to the radial gas forces on the four rotor pairs including the second-stage first rotor pair, the second-stage second rotor pair, the second-stage third rotor pair, and the second-stage fourth rotor pair. In this way, at least a part of the radial gas forces on both the first-stage first rotor pair and the first-stage second rotor pair can be offset by the radial gas forces on the four rotor pairs including the second-stage first rotor pair, the second-stage second rotor pair, the second-stage third rotor pair, and the second-stage fourth rotor pair, or all of them can be offset to achieve the balance of the radial gas forces, thereby improving the balance of the radial gas forces of the rotors of the screw compressor of the present invention.

[0027] 2. The technical solution of the present invention can balance all the gas forces, making the theoretical gas resultant force of the entire compressor zero, and truly achieving near-zero load on the bearings (only need to bear the weight of the parts, transportation and operation impacts, and mechanical positioning), which greatly improves the service life of the bearings.

[0028] 3. Since a large amount of the load is balanced, the mechanical vibration of the screw compressor of the present invention is correspondingly offset a lot, reducing the noise caused by the mechanical and gas flow pulsations of the compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. The drawings in the following description are only exemplary. For those of ordinary skill in the art, without creative efforts, other implementation drawings can be obtained based on the provided drawings.

[0030] Figure 1 It is a schematic diagram of the rotor structure of a screw compressor provided by an embodiment of the present invention;

[0031] Figure 2 It is a cross-sectional view of a screw compressor provided by an embodiment of the present invention;

[0032] Figure 3 It is Figure 2 A cross-sectional view taken along the line A-A in

[0033] Figure 4 It is Figure 2 A cross-sectional view taken along the line B-B in

[0034] Figure 5It is a schematic diagram of the radial gas forces on the rotors of a screw compressor provided by an embodiment of the present invention;

[0035] Figure 6 It is an assembly schematic diagram of the rotor structure and bearings of a screw compressor provided by an embodiment of the present invention;

[0036] Figure 7 It is another assembly schematic diagram of the rotor structure and bearings of a screw compressor provided by an embodiment of the present invention.

[0037] The reference numerals are:

[0038] 1. First rotor pair of the first stage; 2. Second rotor pair of the first stage; 3. First flow channel; 4. Housing; 5. Second flow channel; 6. First bearing; 7. Second bearing; 8. Third bearing; 9. Fourth bearing; 10a. Fifth bearing; 10b. Sixth bearing; 11. First rotor pair of the second stage; 12. Second rotor pair of the second stage; 13. First rotating shaft; 14. Second rotating shaft; 21. Third rotor pair of the second stage; 22. Fourth rotor pair of the second stage; 31. First gas inlet; 32. Second gas inlet; 33. Third gas inlet; 34. Fourth gas inlet; 35. Fifth gas inlet; 41. First compression chamber; 42. Second compression chamber; 43. Third compression chamber; 401. First exhaust port; 403. Second exhaust port; 501. Second A gas inlet; 502. Second B gas inlet; 503. Second C gas inlet; a. Mid-plane. Detailed implementation manners

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0040] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by orientation words such as "front, back, up, down, left, right", "horizontal, vertical, perpendicular, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description. Without contrary description, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the protection scope of the present invention; the orientation words "inside, outside" refer to the inside and outside relative to the contour of each component itself.

[0041] For ease of description, spatial relative terms, such as "above", "over", "on the upper surface", "upper", etc., may be used herein to describe the spatial positional relationship of one device or feature to other devices or features as shown in the figures. It should be understood that the spatial relative terms are intended to encompass different orientations in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, a device described as "above" or "over" other devices or structures will then be positioned "below" or "beneath" the other devices or structures. Thus, the exemplary term "above" can include both the orientations of "above" and "below". The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the corresponding explanations will be made for the spatial relative descriptions used herein.

[0042] In addition, it should be noted that the use of terms such as "first" and "second" to define components is only for the convenience of differentiating the corresponding components. Without further statement, the above terms have no special meanings, and thus should not be construed as limiting the protection scope of the present invention.

[0043] Referring to Figures 1-7 As shown, according to an embodiment of the present invention, a screw compressor is provided, which includes a plurality of rotor pairs, and each rotor pair has a pair of meshing male rotor and female rotor. The male rotors of each rotor pair are coaxially arranged, for example, all arranged on the first rotating shaft 13. The female rotors of each rotor pair are also coaxially arranged, for example, all arranged on the second rotating shaft 14. The first rotating shaft 13 and the second rotating shaft 14 are parallel to each other.

[0044] Among them, each rotor pair is respectively a second-stage first rotor pair 11, a second-stage second rotor pair 12, a first-stage first rotor pair 1, a first-stage second rotor pair 2, a second-stage third rotor pair 21, and a second-stage fourth rotor pair 22. The second-stage first rotor pair 11 and the second-stage second rotor pair 12 are symmetrically arranged, the first-stage first rotor pair 1 and the first-stage second rotor pair 2 are symmetrically arranged, and the second-stage third rotor pair 21 and the second-stage fourth rotor pair 22 are symmetrically arranged.

[0045] Each of the above rotor pairs inhales from one side of its meshing position and exhales from the other side of its meshing position. Moreover, the inhalation sides of the first-stage first rotor pair 1 and the first-stage second rotor pair 2 are opposite to the inhalation sides of the second-stage first rotor pair 11, the second-stage second rotor pair 12, the second-stage third rotor pair 21, and the second-stage fourth rotor pair 22. Correspondingly, the exhaust sides of the first-stage first rotor pair 1 and the first-stage second rotor pair 2 are also opposite to the exhaust sides of the second-stage first rotor pair 11, the second-stage second rotor pair 12, the second-stage third rotor pair 21, and the second-stage fourth rotor pair 22.

[0046] In the above example, since the second-stage first rotor pair 11 and the second-stage second rotor pair 12 are symmetrically arranged, the axial gas force on the second-stage first rotor pair 11 can be equal in magnitude and opposite in direction to the axial gas force on the second-stage second rotor pair 12, so that the axial gas forces on the second-stage first rotor pair 11 and the second-stage second rotor pair 12 can cancel each other out and reach equilibrium. Similarly, the first-stage first rotor pair 1 and the first-stage second rotor pair 2 are symmetrically arranged, so that the axial gas force on the first-stage first rotor pair 1 can be equal in magnitude and opposite in direction to the axial gas force on the first-stage second rotor pair 2, so that the axial gas forces on the first-stage first rotor pair 1 and the first-stage second rotor pair 2 can cancel each other out and reach equilibrium. Similarly, the second-stage third rotor pair 21 and the second-stage fourth rotor pair 22 are symmetrically arranged, so that the axial gas force on the second-stage third rotor pair 21 can be equal in magnitude and opposite in direction to the axial gas force on the second-stage fourth rotor pair 22, so that the axial gas forces on the second-stage third rotor pair 21 and the second-stage fourth rotor pair 22 can cancel each other out and reach equilibrium. Among them, since the axial gas forces on each rotor pair are canceled out and reach equilibrium, the axial gas force balance of the rotor of the screw compressor of the present invention can be ensured.

[0047] In addition, since the suction sides of the first-stage first rotor pair 1 and the first-stage second rotor pair 2 are opposite to the suction sides of the second-stage first rotor pair 11, the second-stage second rotor pair 12, the second-stage third rotor pair 21, and the second-stage fourth rotor pair 22, and the discharge sides of the first-stage first rotor pair 1 and the first-stage second rotor pair 2 are also opposite to the discharge sides of the second-stage first rotor pair 11, the second-stage second rotor pair 12, the second-stage third rotor pair 21, and the second-stage fourth rotor pair 22, the radial gas forces on the first-stage first rotor pair 1 and the first-stage second rotor pair 2 are opposite in direction to the radial gas forces on the second-stage first rotor pair 11, the second-stage second rotor pair 12, the second-stage third rotor pair 21, and the second-stage fourth rotor pair 22. In this way, the radial gas forces on the first-stage first rotor pair 1 and the first-stage second rotor pair 2 can cancel at least a part of the radial gas forces on the second-stage first rotor pair 11, the second-stage second rotor pair 12, the second-stage third rotor pair 21, and the second-stage fourth rotor pair 22, or all cancel to reach the balance of the radial gas force, thereby improving the balance of the radial gas force of the rotor of the screw compressor of the present invention.

[0048] In some embodiments, the resultant radial force received by the first-stage first rotor pair 1 and the first-stage second rotor pair 2 is F 合1 , and the resultant radial force received by the second-stage first rotor pair 11, the second-stage second rotor pair 12, the second-stage third rotor pair 21, and the second-stage fourth rotor pair 22 is F 合2 . Among them, F 合1 and F 合2They are equal in magnitude and opposite in direction, so that all the radial gas forces received during the operation of all the rotors of the screw compressor of the present invention can be fully offset, achieving a complete balance of the radial gas forces of the rotors.

[0049] Among them, since the axial gas forces on each rotor pair are also offset and balanced, the above technical solution can fully offset all the axial and radial forces received during the operation of the rotors. The bearing load is stable under all working conditions, and a single small bearing can be selected for the final margin load support, making the rotor mechanical operation more efficient and reliable. In addition, since all the axial gas forces and radial gas forces are balanced, the theoretical gas resultant force of the entire screw compressor of the present invention is zero, truly realizing near-zero bearing load (only need to bear the part weight, transportation and operation impacts, and mechanical positioning), greatly improving the bearing service life. In addition, due to a large amount of load balancing, the mechanical vibration of the screw compressor of the present invention is also offset a lot, reducing the noise caused by the mechanical and air flow pulsation of the compressor.

[0050] In order to make the aforementioned F 合1 and F 合2 equal in magnitude and opposite in direction, in some embodiments, the aforementioned second-stage first rotor pair 11 and the second-stage fourth rotor pair 22 are symmetrically arranged, so that the structures of the second-stage first rotor pair 11 and the second-stage third rotor pair 21 are the same, and the structures of the second-stage second rotor pair 12 and the second-stage fourth rotor pair 22 are also the same.

[0051] Among them, as Figures 3-5 shown, the radial resultant force received by the male rotor of the aforementioned first-stage first rotor pair 1 is F1, the radial resultant force received by the female rotor of the first-stage first rotor pair 1 is F2, the radial resultant force received by the male rotor of the second-stage first rotor pair 11 is F4, and the radial resultant force received by the female rotor of the second-stage first rotor pair 11 is F3. Among them, F1 and F3 are opposite in direction, and F1 = 2 * F3; F2 and F4 are opposite in direction, and F2 = 2 * F4.

[0052] In the above example, since the second-stage first rotor pair 11 and the second-stage second rotor pair 12 are symmetrically arranged, the radial resultant force on the male rotor of the second-stage second rotor pair 12 is F4, and the radial resultant force on the female rotor of the second-stage second rotor pair 12 is F3. Since the first-stage first rotor pair 1 and the first-stage second rotor pair 2 are symmetrically arranged, the radial resultant force on the male rotor of the first-stage second rotor pair 2 is F1, and the radial resultant force on the female rotor of the first-stage second rotor pair 2 is F2. Since the second-stage first rotor pair 11 and the second-stage fourth rotor pair 22 are symmetrically arranged, and the second-stage third rotor pair 21 is also symmetrically arranged with the second-stage fourth rotor pair 22, the radial resultant forces on the male rotors of both the second-stage third rotor pair 21 and the second-stage fourth rotor pair 22 are F4, and the radial resultant forces on the female rotors of both the second-stage third rotor pair 21 and the second-stage fourth rotor pair 22 are F3. Thus, with the cooperation that the directions of F1 and F3 are opposite, and F1 = 2 * F3; the directions of F2 and F4 are opposite, and F2 = 2 * F4, it is possible to make F 合1 and F 合2 equal in magnitude and opposite in direction to each other.

[0053] In a specific application example, the aforementioned F1 = F2, and F3 = F4. In this example, the male and female rotors of each rotor pair can be designed symmetrically, which is beneficial for making F1 = F2 and F3 = F4. Among them, since the male and female rotors of each rotor pair are both designed symmetrically, it has the advantages of convenient design and processing.

[0054] In some embodiments, the end face profiles of the rotors within the first-stage first rotor pair 1 and the first-stage second rotor pair 2 are the same, and both are the first end face profile. The end face profiles of the rotors within the four rotor pairs of the second-stage first rotor pair 11, the second-stage second rotor pair 12, the second-stage third rotor pair 21, and the second-stage fourth rotor pair 22 are the same, and both are the second end face profile. The first end face profile and the second end face profile are in an equal-proportion scaling relationship.

[0055] In the above example, the first end face profile is used for the end face profiles of the male and female rotors within the first-stage first rotor pair 1 and the first-stage second rotor pair 2, and the second end face profile is used for the end face profiles of the male and female rotors within the four rotor pairs of the second-stage first rotor pair 11, the second-stage second rotor pair 12, the second-stage third rotor pair 21, and the second-stage fourth rotor pair 22. Among them, by making the first end face profile and the second end face profile in an equal-proportion scaling relationship, the design, calculation, and production difficulties can be simplified.

[0056] Among them, the first end face profile and the second end face profile preferably have the same type of composed tooth curves, and only perform equal-proportion scaling to form "similar end face profiles" similar to "similar triangles".

[0057] In some embodiments, such asFigure 2 As shown, the suction sides of the aforementioned second-stage first rotor pair 11, second-stage second rotor pair 12, second-stage third rotor pair 21, and second-stage fourth rotor pair 22 are all used to suck air from the exhaust sides of the first-stage first rotor pair 1 and the first-stage second rotor pair 2, so that the screw compressor of the present invention can achieve two-stage compression.

[0058] In some embodiments, such as Figure 2 As shown, the aforementioned second-stage first rotor pair 11, second-stage second rotor pair 12, first-stage first rotor pair 1, first-stage second rotor pair 2, second-stage third rotor pair 21, and second-stage fourth rotor pair 22 are arranged in sequence along the first direction. The first direction is the axial direction of the shafts where the male rotors of each rotor pair are located.

[0059] In the above example, arranging the first-stage rotor pairs between two sets of second-stage rotor pairs is beneficial to the force balance of the rotor structure.

[0060] In order to achieve the function that the suction sides of the aforementioned second-stage first rotor pair 11, second-stage second rotor pair 12, second-stage third rotor pair 21, and second-stage fourth rotor pair 22 are all used to suck air from the exhaust sides of the first-stage first rotor pair 1 and the first-stage second rotor pair 2, in some embodiments, such as Figure 2 As shown, the aforementioned screw compressor further includes a housing 4. The housing 4 has a separated first compression chamber 41, second compression chamber 42, and third compression chamber 43. The aforementioned second-stage first rotor pair 11 and second-stage second rotor pair 12 are arranged in the first compression chamber 41. The aforementioned first-stage first rotor pair 1 and first-stage second rotor pair 2 are arranged in the second compression chamber 42. The aforementioned second-stage third rotor pair 21 and second-stage fourth rotor pair 22 are arranged in the third compression chamber 43. Among them, a first flow channel 3 is provided inside the housing 4. The first flow channel 3 has a first air passage port 31, second air passage port 32, third air passage port 33, fourth air passage port 34, and fifth air passage port 35. Both the first air passage port 31 and the second air passage port 32 communicate with the first compression chamber 41, and the suction side of the second-stage first rotor pair 11 sucks air through the first air passage port 31, and the suction side of the second-stage second rotor pair 12 sucks air through the second air passage port 32. Both the third air passage port 33 and the fourth air passage port 34 communicate with the third compression chamber 43, and the suction side of the second-stage third rotor pair 21 sucks air through the third air passage port 33, and the suction side of the second-stage fourth rotor pair 22 sucks air through the fourth air passage port 34. The fifth air passage port 35 communicates with the second compression chamber 42, and the exhaust sides of both the first-stage first rotor pair 1 and the first-stage second rotor pair 2 exhaust air through the fifth air passage port 35.

[0061] In the above example, the exhaust gases of both the first-stage first rotor pair 1 and the first-stage second rotor pair 2 flow into the first flow channel 3 from the fifth gas passage port 35, and then are divided into four streams. One stream flows into the suction side of the second-stage first rotor pair 11 from the first gas passage port 31, one stream flows into the suction side of the second-stage second rotor pair 12 from the second gas passage port 32, one stream flows into the suction side of the second-stage third rotor pair 21 from the third gas passage port 33, and one stream flows into the suction side of the second-stage fourth rotor pair 22 from the fourth gas passage port 34. Thus, the suction sides of the above-mentioned second-stage first rotor pair 11, second-stage second rotor pair 12, second-stage third rotor pair 21, and second-stage fourth rotor pair 22 are all used to suck air from the exhaust sides of both the first-stage first rotor pair 1 and the first-stage second rotor pair 2.

[0062] In some embodiments, as Figure 2 shown, the aforementioned first flow channel 3 is symmetrically arranged with respect to the mid-plane a of both the first-stage first rotor pair 1 and the first-stage second rotor pair 2.

[0063] In the above example, the shape of the first flow channel 3 affects the pressure loss of the air flow, and the pressure values will differ after the air flow passes through different flow channels. The mirror-symmetrical design of the first flow channel 3 of the present invention is to eliminate the situation where the force balance is not complete and the forces cannot be completely offset due to the pressure loss; actually, subtle differences are inevitable, but the corresponding force differences will also be extremely small and will not affect the operation of the shafting. However, in the design, it is necessary to ensure that the dimensions are consistent and completely mirror-imaged, and the errors only occur in application and production.

[0064] In some embodiments, as Figure 2 shown, when the screw compressor includes a housing 4, and the housing 4 has a separated first compression chamber 41, second compression chamber 42, and third compression chamber 43; both the second-stage first rotor pair 11 and the second-stage second rotor pair 12 are arranged in the first compression chamber 41, both the first-stage first rotor pair 1 and the first-stage second rotor pair 2 are arranged in the second compression chamber 42, and both the second-stage third rotor pair 21 and the second-stage fourth rotor pair 22 are arranged in the third compression chamber 43, the aforementioned first compression chamber 41 has a first exhaust port 401, and the exhaust sides of both the second-stage first rotor pair 11 and the second-stage second rotor pair 12 exhaust through the first exhaust port 401. The third compression chamber 43 has a second exhaust port 403, and the exhaust sides of both the second-stage third rotor pair 21 and the second-stage fourth rotor pair 22 exhaust through the second exhaust port 403. Among them, the first exhaust port 401 and the second exhaust port 403 are symmetrically arranged with respect to the mid-plane a of both the first-stage first rotor pair 1 and the first-stage second rotor pair 2 to further eliminate the situation where the force balance is not complete and the forces cannot be completely offset due to the pressure loss, and improve the balance of the forces on the rotor.

[0065] In some embodiments, as Figure 2As shown in the figure, the aforementioned body 4 has a second flow channel 5, and the second flow channel 5 has a second A air inlet 501, a second B air inlet 502, and a second C air inlet 503. Both the second B air inlet 502 and the second C air inlet 503 are communicated with the second compression cavity 42, and the suction side of the first-stage first rotor pair 1 sucks air through the second B air inlet 502, and the suction side of the first-stage second rotor pair 2 sucks air through the second C air inlet 503. The second A air inlet 501 penetrates through the outer wall of the body 4. The second flow channel 5 is symmetrically arranged with respect to the mid-plane a of both the first-stage first rotor pair 1 and the first-stage second rotor pair 2 to further eliminate the incomplete force balance and the situation where the forces cannot be completely offset caused by pressure loss, and improve the balance of the forces on the rotor.

[0066] Regarding the design of the bearing placement position, in the first example, as Figure 6 shown, a first bearing 6 is sleeved on the shaft section between the male rotors of the aforementioned second-stage second rotor pair 12 and the first-stage first rotor pair 1, and a second bearing 7 is sleeved on the shaft section between the female rotors of the two. A third bearing 8 is sleeved on the shaft section between the male rotors of the second-stage third rotor pair 21 and the first-stage second rotor pair 2, and a fourth bearing 9 is sleeved on the shaft section between the female rotors of the two. In the second example, as Figure 7 shown, fifth bearings 10a are provided at both ends of the rotating shafts where the male rotors of each rotor pair are located, and sixth bearings 10b are provided at both ends of the rotating shafts where the female rotors of each rotor pair are located. In the third example, for the case where the stiffness is slightly weaker or considering that the rotor is too long, bearings can also be installed on the above-mentioned shaft sections to ensure the stable operation of the machine, that is, a first bearing 6 is sleeved on the shaft section between the male rotors of the aforementioned second-stage second rotor pair 12 and the first-stage first rotor pair 1, and a second bearing 7 is sleeved on the shaft section between the female rotors of the two. A third bearing 8 is sleeved on the shaft section between the male rotors of the second-stage third rotor pair 21 and the first-stage second rotor pair 2, and a fourth bearing 9 is sleeved on the shaft section between the female rotors of the two. And fifth bearings 10a are provided at both ends of the rotating shafts where the male rotors of each rotor pair are located, and sixth bearings 10b are provided at both ends of the rotating shafts where the female rotors of each rotor pair are located. In this third example, the increase in the number of bearings here is only to stabilize the stiffness of the shafting. Compared with the case where about 10 bearings are required for a single rotor pair, the number of bearings in the third example solution has been greatly reduced.

[0067] It should be noted here that: in order to make the directions of the aforementioned F1 and F3 opposite to each other, and F1 = 2 * F3; the directions of F2 and F4 are opposite to each other, and F2 = 2 * F4, to offset all the radial gas forces on the rotor, a specific design method is given below:

[0068] 1. Determine the end face profiles of two sets of male and female rotors, namely the aforementioned first end face profile and the second end face profile. The first end face profile is used for the first-stage first rotor pair 1 and the first-stage second rotor pair 2, and the second end face profile is used for the aforementioned second-stage first rotor pair 11, second-stage second rotor pair 12, second-stage third rotor pair 21, and second-stage fourth rotor pair 22. To simplify the design, calculation, and production difficulties, it is preferred that the first end face profile and the second end face profile have the same type of composed tooth curves, and only perform equal-proportion scaling to form "similar end face profiles" similar to "similar triangles".

[0069] 2. Determine the working section lengths and the shapes and sizes of the exhaust port openings for both the first-stage first rotor pair 1 and the first-stage second rotor pair 2. The exhaust port openings here are the aforementioned fifth air passage port 35, and obtain the force results for both the first-stage first rotor pair 1 and the first-stage second rotor pair 2 through simulation calculation, including the magnitude and direction of the forces. Since the first-stage first rotor pair 1 and the first-stage second rotor pair 2 are completely mirror-image designs, the axial gas forces on both of them will necessarily cancel each other out, while the radial gas forces are two sets of forces with the same direction and equal magnitude, both being F1 and F2, and the force directions are the included angles α and β respectively (as Figure 3 shown).

[0070] 3. Start determining the lengths of the second-stage first rotor pair 11, second-stage second rotor pair 12, second-stage third rotor pair 21, and second-stage fourth rotor pair 22 based on the forces of F1 and F2. Through the process of "formulating the length - calculating the obtained force value - correcting the length", finally obtain four sets of forces, all being F3 and F4, and 2×F3 = F1, 2×F4 = F2 (as Figure 4 shown). Note here that due to the adoption of the "similar end face profile" design, when the lengths of the second-stage first rotor pair 11, second-stage second rotor pair 12, second-stage third rotor pair 21, and second-stage fourth rotor pair 22 ensure 2×F3 = F1, there will also necessarily be 2×F4 = F2. If different types and non-similar end face profiles are used for each first-stage rotor pair and each second-stage rotor pair, it is very difficult to ensure 2×F4 = F2 when ensuring 2×F3 = F1. At this time, profile modification is also required to meet the requirements. In theory, 2×F3 = F1 and 2×F4 = F2 can ultimately be achieved through profile modification, but it is very troublesome.

[0071] 4. Similarly, determine the force directions of the second-stage first rotor pair 11, second-stage second rotor pair 12, second-stage third rotor pair 21, and second-stage fourth rotor pair 22 according to the shapes and sizes of the exhaust port openings. Also due to the adoption of the "similar end face profile", directly adopt "similar exhaust port openings" here, that is, the shapes and sizes of the aforementioned first exhaust port 401 and the second exhaust port 403 have an equal-proportion scaling relationship with the shape and size of the aforementioned fifth air passage port 35. And place the "similar exhaust port openings" in opposite orientations (as shown in the appendix Figure 2As shown, the suction of both the first-stage first rotor pair 1 and the first-stage second rotor pair 2 is on the upper side, and the exhaust is on the lower side; the situation of each second-stage rotor pair is completely opposite, i.e., the suction of the second-stage first rotor pair 11, the second-stage second rotor pair 12, the second-stage third rotor pair 21, and the second-stage fourth rotor pair 22 is on the lower side, and the exhaust is on the upper side). In this way, the force directions of the second-stage first rotor pair 11, the second-stage second rotor pair 12, the second-stage third rotor pair 21, and the second-stage fourth rotor pair 22 can be made completely consistent and completely opposite to those of the first-stage first rotor pair 1 and the first-stage second rotor pair 2.

[0072] The present invention also provides an air conditioner, which may include the screw compressor of any one of the above. Among them, due to the adoption of the above screw compressor in the air conditioner, the balance of the axial gas force of the rotor can be ensured while improving the balance of the radial gas force of the rotor.

[0073] For the convenience of understanding, the overall structure of the present invention will be described below, and its working principle will be elaborated.

[0074] The screw compressor of the present invention has a multi-rotor two-stage compressor structure. Through 2 types (i.e., two types of rotor pairs: the first-stage rotor pair and the second-stage rotor pair), 3 groups of rotor pairs (the second-stage first rotor pair 11 and the second-stage second rotor pair 12 form the first group, the first-stage first rotor pair 1 and the first-stage second rotor pair 2 form the second group, and the second-stage third rotor pair 21 and the second-stage fourth rotor pair 22 form the third group), and 4 rotors are symmetrically arranged in each group of rotor pairs. In total, there are 8 types and 12 rotors in the symmetric cancellation scheme, achieving complete cancellation of the gas force, greatly reducing the load and the amplitude of load change of the shafting under all working conditions, streamlining the structure, reducing the cost, increasing the service life of the bearings, improving the reliability, and at the same time, it can also reduce the noise and vibration caused by the mechanical and air flow pulsation of the compressor to a certain extent.

[0075] As shown in the appendix Figure 1 As shown, there are a total of 12 rotors in the second-stage first rotor pair 11, the second-stage second rotor pair 12, the first-stage first rotor pair 1, the first-stage second rotor pair 2, the second-stage third rotor pair 21, and the second-stage fourth rotor pair 22 of the present invention. Every 6 rotors are connected in series on one shaft. From the perspective of diameter, there are 2 types of rotor pairs with different diameters; from the perspective of rotation direction, there are 2 types of rotor pairs with different rotation directions.

[0076] The working process of the screw compressor of the present invention is as follows: Gas enters the compressor through the second A air inlet 501, is evenly divided into two paths and is compressed by the first-stage first rotor pair 1 and the first-stage second rotor pair 2 respectively. The axial forces generated during this process are opposite to each other and cancel each other out. After the two exhaust gases are combined, they flow into the first flow channel 3 from the fifth air inlet 35, and then are divided into four paths and enter the first air inlet 31, the second air inlet 32, the third air inlet 33 and the fourth air inlet 34 respectively, and are compressed by the second-stage first rotor pair 11, the second-stage second rotor pair 12, the second-stage third rotor pair 21 and the second-stage fourth rotor pair 22 respectively, and then are discharged through two exhaust ports, namely the first exhaust port 401 and the second exhaust port 403.

[0077] In this process, due to the completely mirror-image rotor pairs, the first flow channel 3 and the second flow channel 5, the axial forces at both ends of the middle parting surface a between the first-stage first rotor pair 1 and the first-stage second rotor pair 2 are offset in a manner of the same magnitude and opposite directions generated by several completely symmetric rotor pairs, and the engineering deviations existing during this period are borne by a small number of bearings.

[0078] As shown in the appendix Figures 3-5 shown, through the design of the opening degree of the exhaust orifice, it is ensured that the exhaust port angles of several rotor pairs are consistent, and the gas force directions opposite to the exhaust direction, that is, as shown in the appendix Figure 3 and 4 shown, can also be completely controlled, ensuring that the resultant radial gas forces of the first-stage compression and the second-stage compression are the same in magnitude and opposite in direction; if complete gas force balance is pursued, rotors and hole housing flow channels with different magnitudes but equivalent proportional relationships should be used, resulting in exactly the same force application angles, that is, as shown in Figure 3 and 4 shown, the α and β angles. Ensure the direction with this angle and ensure the magnitude of the force with the rotor length. As long as the magnitude and direction can be determined to cancel each other out. In fact, during actual use, some sacrifices in balance can also be made according to the actual needs of users to better meet the actual working conditions. At this time, although there are unbalanced other forces that are not completely cancelled, they are also very small, and slightly larger bearings can handle them. Similarly, the axial force can also be considered to be unbalanced to a certain extent in actual applications to ensure that the deviation direction is controllable, and a single-direction support bearing is selected to bear it.

[0079] Among them, α and β are angular dimensions for conveniently calibrating the radial force directions of the first-stage and second-stage rotor pairs during the design process. The rotor pair consists of a male rotor and a female rotor. Here, α and β respectively correspond to the radial force calibration angles of the male rotor and the female rotor. During the design process, it is necessary to ensure that the α angles and β angles of the first-stage and second-stage rotor pairs are equivalent, which also ensures that the force application directions of the rotors are on the same straight line. For this point, refer to the appendix Figure 3Schematic diagrams of the directions of F1 and F3, and F2 and F4. Actually, in terms of the same marking reference, for the force F1 of the first-stage rotor pair, the corresponding α angle, and for F3 opposite to it, the corresponding angle should be (180° + α) for accuracy. The same applies to F2 and F4.

[0080] Among them, when the rotor pair is working, the male and female rotors will bear certain forces under the corresponding intake and exhaust pressures. When the working pressures at each location are determined: the magnitudes of the forces on rotors of different sizes can be accurately calculated, and the torsional degrees and the opening positions of the intake / exhaust ports of different rotors can accurately control the directions of the forces. On this basis, the above-mentioned rotor pairs can be designed to ensure that under the target working conditions (i.e., the target intake, exhaust, and intermediate process pressures), the radial resultant forces of the first-stage rotor pair and the second-stage rotor pair are equal in magnitude and opposite in direction.

[0081] It is easy for those skilled in the art to understand that, on the premise of no conflict, the advantageous technical features of the above various methods can be freely combined and superimposed.

[0082] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above is only the preferred implementation manner of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as within the protection scope of the present invention.

Claims

1. A screw compressor, characterized in that: It includes multiple rotor pairs, each of the rotor pairs has a pair of meshing male rotor and female rotor, the male rotors of each of the rotor pairs are coaxially arranged, and the female rotors of each of the rotor pairs are coaxially arranged; Among them, each of the rotor pairs is respectively a second-stage first rotor pair (11), a second-stage second rotor pair (12), a first-stage first rotor pair (1), a first-stage second rotor pair (2), a second-stage third rotor pair (21) and a second-stage fourth rotor pair (22); the second-stage first rotor pair (11) and the second-stage second rotor pair (12) are symmetrically arranged, the first-stage first rotor pair (1) and the first-stage second rotor pair (2) are symmetrically arranged, and the second-stage third rotor pair (21) and the second-stage fourth rotor pair (22) are symmetrically arranged; Each of the rotor pairs sucks air from one side of its meshing position and discharges air from the other side of its meshing position; and the suction sides of the first-stage first rotor pair (1) and the first-stage second rotor pair (2) are opposite to the suction sides of the second-stage first rotor pair (11), the second-stage second rotor pair (12), the second-stage third rotor pair (21) and the second-stage fourth rotor pair (22).

2. The screw compressor according to claim 1, wherein: The radial resultant force received by both the first-stage first rotor pair (1) and the first-stage second rotor pair (2) is F 合1 , and the radial resultant force received by the four of the second-stage first rotor pair (11), the second-stage second rotor pair (12), the second-stage third rotor pair (21), and the second-stage fourth rotor pair (22) is F 合2 ; Among them, F 合1 and F 合2 are equal in magnitude and opposite in direction.

3. The screw compressor according to claim 2, wherein: The second-stage first rotor pair (11) and the second-stage fourth rotor pair (22) are symmetrically arranged; and the radial resultant force received by the male rotor of the first-stage first rotor pair (1) is F1, the radial resultant force received by the female rotor of the first-stage first rotor pair (1) is F2, the radial resultant force received by the male rotor of the second-stage first rotor pair (11) is F4, and the radial resultant force received by the female rotor of the second-stage first rotor pair (11) is F3; Among them, the directions of F1 and F3 are opposite, and F1 = 2 * F3; the directions of F2 and F4 are opposite, and F2 = 2 * F4.

4. The screw compressor according to any one of claims 1-3, wherein: The end face profiles of the rotors in the first-stage first rotor pair (1) and the first-stage second rotor pair (2) are the same, and are both the first end face profile; the end face profiles of the rotors in the second-stage first rotor pair (11), the second-stage second rotor pair (12), the second-stage third rotor pair (21) and the second-stage fourth rotor pair (22) are the same, and are both the second end face profile; The first end face profile and the second end face profile are in a proportional scaling relationship.

5. The screw compressor according to any one of claims 1-3, wherein: The suction sides of the second-stage first rotor pair (11), the second-stage second rotor pair (12), the second-stage third rotor pair (21) and the second-stage fourth rotor pair (22) are all used to suck air from the exhaust sides of the first-stage first rotor pair (1) and the first-stage second rotor pair (2).

6. The screw compressor according to claim 5, wherein: The secondary first rotor pair (11), the secondary second rotor pair (12), the primary first rotor pair (1), the primary second rotor pair (2), the secondary third rotor pair (21) and the secondary fourth rotor pair (22) are arranged in sequence along a first direction, and the first direction is the axial direction of the shafts where the male rotors of the rotor pairs are located.

7. The screw compressor according to claim 6, characterized in that: It further includes a housing (4), and a first compression chamber (41), a second compression chamber (42) and a third compression chamber (43) separated from each other are provided in the housing (4); both the secondary first rotor pair (11) and the secondary second rotor pair (12) are arranged in the first compression chamber (41), both the primary first rotor pair (1) and the primary second rotor pair (2) are arranged in the second compression chamber (42), and both the secondary third rotor pair (21) and the secondary fourth rotor pair (22) are arranged in the third compression chamber (43); wherein, a first flow passage (3) is provided inside the housing (4), and the first flow passage (3) has a first air inlet (31), a second air inlet (32), a third air inlet (33), a fourth air inlet (34) and a fifth air inlet (35); both the first air inlet (31) and the second air inlet (32) communicate with the first compression chamber (41), and the suction side of the secondary first rotor pair (11) sucks air through the first air inlet (31), and the suction side of the secondary second rotor pair (12) sucks air through the second air inlet (32); both the third air inlet (33) and the fourth air inlet (34) communicate with the third compression chamber (43), and the suction side of the secondary third rotor pair (21) sucks air through the third air inlet (33), and the suction side of the secondary fourth rotor pair (22) sucks air through the fourth air inlet (34); the fifth air inlet (35) communicates with the second compression chamber (42), and the exhaust sides of both the primary first rotor pair (1) and the primary second rotor pair (2) exhaust air through the fifth air inlet (35).

8. The screw compressor according to claim 7, wherein: The first flow passage (3) is symmetrically arranged with respect to the mid-plane (a) of both the primary first rotor pair (1) and the primary second rotor pair (2).

9. The screw compressor according to any one of claims 1-3, 6-8, characterized in that: When the screw compressor includes a housing (4), and a first compression chamber (41), a second compression chamber (42) and a third compression chamber (43) separated from each other are provided in the housing (4); both the secondary first rotor pair (11) and the secondary second rotor pair (12) are arranged in the first compression chamber (41), both the primary first rotor pair (1) and the primary second rotor pair (2) are arranged in the second compression chamber (42), and both the secondary third rotor pair (21) and the secondary fourth rotor pair (22) are arranged in the third compression chamber (43), wherein, The first compression chamber (41) has a first exhaust port (401). The exhaust sides of both the second-stage first rotor pair (11) and the second-stage second rotor pair (12) exhaust through the first exhaust port (401). The third compression chamber (43) has a second exhaust port (403). The exhaust sides of both the second-stage third rotor pair (21) and the second-stage fourth rotor pair (22) exhaust through the second exhaust port (403). The first exhaust port (401) and the second exhaust port (403) are symmetrically arranged with respect to the mid-plane (a) of both the first-stage first rotor pair (1) and the first-stage second rotor pair (2). And / or, a second flow path (5) is provided in the housing (4). The second flow path (5) has a second A air inlet (501), a second B air inlet (502), and a second C air inlet (503). The second B air inlet (502) and the second C air inlet (503) are both in communication with the second compression chamber (42). The suction side of the first-stage first rotor pair (1) sucks air through the second B air inlet (502), and the suction side of the first-stage second rotor pair (2) sucks air through the second C air inlet (503). The second A air inlet (501) penetrates the outer wall of the housing (4). The second flow path (5) is symmetrically arranged with respect to the mid-plane (a) of both the first-stage first rotor pair (1) and the first-stage second rotor pair (2).

10. The screw compressor according to any one of claims 1-3, 6-8, wherein: A first bearing (6) is sleeved on the shaft section between the male rotors of the second-stage second rotor pair (12) and the first-stage first rotor pair (1), and a second bearing (7) is sleeved on the shaft section between the female rotors of the two; a third bearing (8) is sleeved on the shaft section between the male rotors of the second-stage third rotor pair (21) and the first-stage second rotor pair (2), and a fourth bearing (9) is sleeved on the shaft section between the female rotors of the two; And / or, fifth bearings (10a) are provided at both ends of the rotating shafts where the male rotors of each rotor pair are located, and sixth bearings (10b) are provided at both ends of the rotating shafts where the female rotors of each rotor pair are located.

11. An air conditioner, characterized in that: Comprising the screw compressor according to any one of claims 1-10.

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