Gear transmission, two-stage screw compressor and air conditioner

Abstract

The present application relates to a gear transmission device, a two-stage screw compressor, and an air conditioner. The gear transmission device includes: a low-pressure stage rotor, a high-pressure stage rotor, a coupling, and an adjusting gear assembly. The adjusting gear assembly is located on the same side of the low-pressure stage rotor, the high-pressure stage rotor, and the coupling. The adjusting gear assembly includes a first adjusting gear and a second adjusting gear that is coaxially driven with the first adjusting gear. The first adjusting gear is meshed with the outer periphery of the low-pressure stage rotor. Under cooling conditions, the low-pressure stage rotor and the high-pressure stage rotor are coaxially driven through the coupling, and the second adjusting gear is configured to idle. Under heating conditions, the coupling is disengaged from the low-pressure stage rotor, while the coupling remains meshed with the high-pressure stage rotor. The second adjusting gear is configured to mesh with the outer periphery of the coupling.

Description

Technical Field

[0001] The present application relates to the field of compressors, and in particular to a gear transmission device, a two-stage screw compressor and an air conditioner. Background Art

[0002] Two-stage compression with intermediate air injection has been widely used in screw refrigeration compressors. Refrigeration principles indicate that in two-stage compression, system energy efficiency is highest when the intermediate pressure is equal to the square root of (evaporating pressure * condensing pressure). However, in a single-unit two-stage screw compressor, the low-pressure and high-pressure rotors are connected by a coupling to transmit torque. Once the dimensions of the two rotor stages are determined, and the corresponding rotor displacement at each speed is also determined, the intermediate chamber pressure is determined from a circulation perspective. Therefore, in a single-unit two-stage screw compressor, the intermediate pressure is typically equal to the square root of (evaporating pressure * condensing pressure) only under nominal operating conditions.

[0003] When the working conditions change, although the theoretical internal volume ratio of each stage rotor can be adjusted to match different working conditions through the internal volume ratio adjustment slide valve to achieve efficient operation, the intermediate pressure will deviate from the theoretical value of the highest energy efficiency of the system. Summary of the Invention

[0004] The present application provides a gear transmission device, a two-stage screw compressor and an air conditioner to solve the technical problem in the above-mentioned prior art that when the working conditions change, the intermediate pressure of a single-unit two-stage screw compressor deviates from the theoretical value with the highest energy efficiency of the system.

[0005] The present invention provides a gear transmission device, which includes: a low-pressure stage rotor, a high-pressure stage rotor, a coupling and an adjusting gear assembly, wherein the coupling is coaxially connected between the low-pressure stage rotor and the high-pressure stage rotor; the adjusting gear assembly is located on the same side of the low-pressure stage rotor, the high-pressure stage rotor and the coupling, and the adjusting gear assembly includes a first adjusting gear and a second adjusting gear that is coaxially driven with the first adjusting gear, and the first adjusting gear is meshed with the outer periphery of the low-pressure stage rotor for transmission; under cooling conditions, the low-pressure stage rotor and the high-pressure stage rotor are coaxially driven through the coupling, and the second adjusting gear is configured to idle; under heating conditions, the coupling is disengaged from the low-pressure stage rotor, and the coupling remains meshed with the high-pressure stage rotor for transmission, and the second adjusting gear is configured to mesh with the outer periphery of the coupling for transmission.

[0006] Wherein, the coupling includes a first end shaft and a second end shaft. Under the refrigeration working condition, the first end shaft extends into the first inner cavity of the low-pressure stage rotor and is meshed and transmitted with the first inner cavity of the low-pressure stage rotor. The second end shaft extends into the second inner cavity of the high-pressure stage rotor and is meshed and transmitted with the second inner cavity of the high-pressure stage rotor.

[0007] In which, the second inner cavity of the high-pressure stage rotor includes a second meshing section and a second cavity section connected to the second meshing section, the second meshing section is used to engage and transmit with the second end shaft of the coupling, and the second cavity section has a piston mechanism, and the piston mechanism is used to push the coupling to move toward the direction of the low-pressure stage rotor.

[0008] In which, the first inner cavity of the low-pressure stage rotor includes a first meshing section and a first cavity section connected to the first meshing section, the first meshing section is used to engage and transmit with the first end shaft of the coupling, and the first cavity section has a thrust member, which is used to limit the maximum displacement of the coupling toward the low-pressure stage rotor.

[0009] The shaft end of the low-pressure stage rotor has a first toothed shaft section, and the coupling has a third toothed shaft section on the periphery; the first adjusting gear and the second adjusting gear in the adjusting gear assembly are coaxial and spaced apart, and the first adjusting gear is meshed with the first toothed shaft section for transmission;

[0010] Under the heating condition, the coupling moves to the second adjusting gear position and engages with the second adjusting gear for transmission, and the first engaging section of the first inner cavity in the low-pressure stage rotor disengages from the first end shaft in the coupling.

[0011] Wherein, the number of teeth of the second adjusting gear is smaller than the number of teeth of the first adjusting gear.

[0012] The number of teeth of the first toothed shaft segment is greater than the number of teeth of the third toothed shaft segment.

[0013] Among them, the meshing structures adopted in each meshing transmission position all adopt a spline structure.

[0014] The present invention further provides a two-stage screw compressor, comprising the above-mentioned gear transmission device.

[0015] The present invention also provides an air conditioner, comprising the above-mentioned two-stage screw compressor.

[0016] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0017] The gear transmission device, two-stage screw compressor and air conditioner provided in the embodiments of the present application can obtain a structure that can adjust the high-pressure stage exhaust volume of a single two-stage screw compressor by changing the meshing transmission relationship between the high-pressure stage rotor, the low-pressure stage rotor and the coupling, which is used to match the theoretical intermediate pressure of the system. Through such a structural setting, the synchronous rotation between the low-pressure stage rotor, the coupling and the high-pressure stage rotor can be achieved under the refrigeration condition, and the high-pressure stage rotor speed can be adjusted separately under the heating condition. During the process, the coupling rotates synchronously with the high-pressure stage rotor, and the coupling will not drive the low-pressure stage rotor to rotate synchronously, thereby adjusting the pressure ratio distribution of each stage of the compressor, so as to achieve the theoretical optimal pressure ratio distribution under different working conditions, thereby improving the energy efficiency of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0021] Figure 1 A schematic diagram of the meshing state structure of the gear transmission device under refrigeration conditions provided in an embodiment of the present application;

[0022] Figure 2 A schematic diagram of the structure of the instantaneous state (just beginning to engage) of speed change provided by an embodiment of the present application;

[0023] Figure 3 A schematic diagram of the meshing state structure of the gear transmission device under heating conditions provided in an embodiment of the present application;

[0024] Figure 4 This is a schematic structural diagram of each meshing structure 7 in the gear transmission device provided in an embodiment of the present application.

[0025] Description of reference numerals:

[0026] 1. Low-pressure stage rotor; 11. First inner cavity; 111. First meshing section; 112. First cavity section; 12. First toothed shaft section; 2. High-pressure stage rotor; 21. Second inner cavity; 211. Second meshing section; 212. Second cavity section; 22. Second toothed shaft section; 3. Coupling; 31. First end shaft; 32. Second end shaft; 33. Third toothed shaft section; 4. Adjusting gear assembly; 41. First adjusting gear; 42. Second adjusting gear; 5. Piston mechanism; 6. Thrust member; 7. Meshing structure 7. DETAILED DESCRIPTION

[0027] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0028] The disclosure below provides many different embodiments or examples for implementing different configurations of the present invention. To simplify the disclosure of the present invention, the components and configurations of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or configurations discussed.

[0029] For ease of description, spatially relative terms may be used herein to describe the relative position or movement of one element or feature relative to another element or feature as shown in the figures. These relative terms include, for example, "inside," "outside," "inside," "outside," "below," "beneath," "above," "above," "front," "rear," and the like. Such spatially relative terms are intended to encompass different orientations of the device during use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is flipped, changes position, or changes motion, these directional indications will change accordingly. For example, an element described as "below" or "beneath" another element or feature would subsequently be oriented "above" or "above" the other element or feature. Thus, the example term "below" can encompass both above and below orientations. The device may be oriented differently (rotated 90 degrees or in other orientations), and the spatially relative terms used herein should be interpreted accordingly.

[0030] A bipolar screw compressor is a common refrigeration compressor. Its structure generally consists of main components, a working chamber, synchronous gears, and an intermediate air supply device. These components include the low-pressure screw rotor, the high-pressure screw rotor, the compressor body, synchronous gears, shaft seals, bearings, suction and discharge end seats, an intermediate air supply device, and a slide valve. Within the compressor body, the screw rotors and the inner wall of the compressor body form two independent working chambers: the low-pressure chamber and the high-pressure chamber. The low-pressure chamber draws in low-temperature, low-pressure refrigerant gas and performs initial compression, while the high-pressure chamber further compresses the refrigerant from the low-pressure stage to a higher pressure and temperature. The synchronous gears ensure the synchronous operation of the low-pressure and high-pressure rotors, ensuring precise coordination according to a specific transmission ratio to ensure proper operation of the compressor. The intermediate air supply device, located between the low-pressure and high-pressure stages, replenishes refrigerant gas to the intermediate chamber during the compression process, thereby improving compressor performance and efficiency.

[0031] Based on the structure of the bipolar screw compressor described above, the gas compression function and energy regulation function are simultaneously realized. Regarding compression, the working principle of the two-stage screw compressor is based on the basic working principle of the screw compressor, that is, through the rotation of a pair of intermeshing screw rotors in the body, the refrigerant gas is continuously compressed in the volume between the teeth; in two-stage compression, the refrigerant gas is first initially compressed in the low-pressure stage rotor, then enters the intermediate cavity, and after intermediate air replenishment, it enters the high-pressure stage rotor for further compression, and finally reaches the required exhaust pressure. Regarding energy regulation, energy regulation is achieved through a slide valve; the slide valve can change the effective working length of the rotor, thereby adjusting the refrigerant flow rate and compression ratio to adapt to different refrigeration load requirements; for example, when the refrigeration load is low, the slide valve shortens the effective working length of the rotor, reducing the refrigerant flow rate and compression work, and reducing the energy consumption of the compressor.

[0032] During the operation, (the suction process) low-temperature, low-pressure refrigerant gas enters the low-pressure stage working chamber from the suction port. As the low-pressure screw rotor rotates, the inter-tooth volume gradually increases, creating a negative pressure that draws the refrigerant gas in. The suction process ends when the inter-tooth volume reaches its maximum. (The low-pressure compression process) After suction, as the rotor continues to rotate, the inter-tooth volume gradually decreases, compressing the refrigerant gas and gradually increasing its pressure and temperature. During the low-pressure compression process, the refrigerant gas is compressed to an intermediate pressure. (The intermediate refill process) When the refrigerant gas compressed by the low-pressure stage enters the intermediate chamber, the intermediate refill device replenishes a certain amount of intermediate-pressure refrigerant gas. This refill improves the compressor's cooling capacity and energy efficiency while reducing the compressor's discharge temperature. (The high-pressure compression process) After the intermediate refill, the refrigerant gas enters the high-pressure stage working chamber. Under the action of the high-pressure screw rotor, the refrigerant gas is compressed again, further increasing its pressure and temperature until it reaches the condensing pressure. (Exhaust process) The high-temperature and high-pressure refrigerant gas compressed in the high-pressure stage is discharged from the exhaust port and enters the condenser, where it is cooled and condensed into liquid, completing a refrigeration cycle.

[0033] Based on this, bipolar screw compressors can achieve efficient operation under different working conditions through bipolar compression and intermediate air supply technology, and are widely used in various refrigeration and air-conditioning systems.

[0034] Under nominal operating conditions, the design of a single two-stage screw compressor is based on theoretical calculations. At this point, the intermediate pressure is equal to the square root of (evaporating pressure * condensing pressure), an ideal state derived from the thermodynamic principles of the refrigeration cycle. Under this condition, the compression ratios of each compressor stage, refrigerant flow rate, and other parameters are matched to maximize the energy efficiency of the entire system. This is an optimized design based on specific conditions (such as a specific cooling capacity, evaporating temperature, and condensing temperature).

[0035] When operating conditions change, such as changes in ambient temperature or cooling load, the evaporation and condensing pressures will change accordingly. Although the theoretical volume ratio of each rotor can be adjusted using a volume ratio adjustment slide valve at each stage in an attempt to adapt to the new operating conditions and achieve efficient operation, this adjustment method has certain limitations. Volume ratio adjustment primarily adjusts the compression ratio by changing the working volume of the rotor, but it cannot accurately match the various parameter changes brought about by changes in operating conditions. For example, the flow rate and physical properties of the refrigerant will also change with changes in operating conditions, and these factors will also affect the intermediate pressure. Therefore, even if the volume ratio is adjusted, the intermediate pressure may still deviate from the theoretical value when the system is most energy efficient.

[0036] Therefore, a single-unit two-stage screw compressor can achieve ideal intermediate pressure and maximum energy efficiency under nominal operating conditions. However, when the operating conditions change, the intermediate pressure is likely to deviate from the theoretical optimal value due to the complexity of the system parameters and the limitations of the internal volume ratio adjustment method.

[0037] To alleviate the above technical problems, refer to Figure 1-Figure 4 The embodiment of the present application provides a single-unit bipolar screw compressor, which can realize the independent adjustment of the speed of the high-pressure stage rotor 2, thereby adjusting the pressure ratio distribution of each stage of the compressor, so as to achieve the theoretical optimal pressure ratio distribution under different working conditions, thereby improving the energy efficiency of the system, that is, it can realize the two speeds of the high-pressure stage rotor 2 corresponding to the two working conditions and efficient operation.

[0038] An embodiment of the present application provides a gear transmission device that can adjust the high-pressure stage exhaust volume of a single-machine two-stage screw compressor by changing the meshing transmission relationship between the high-pressure stage rotor, the low-pressure stage rotor 1 and the coupling 3, so as to match the theoretical intermediate pressure of the system.

[0039] An embodiment of the present application provides a gear transmission device, including: a low-pressure stage rotor 1, a high-pressure stage rotor 2, a coupling 3 and an adjusting gear assembly 4, the coupling 3 is coaxially connected between the low-pressure stage rotor 1 and the high-pressure stage rotor 2; the adjusting gear assembly 4 is located on the same side of the low-pressure stage rotor 1, the high-pressure stage rotor 2 and the coupling 3, the adjusting gear assembly 4 includes a first adjusting gear 41 and a second adjusting gear 42 that is coaxially driven with the first adjusting gear 41, and the first adjusting gear 41 is meshed with the outer periphery of the low-pressure stage rotor 1; under cooling conditions, the low-pressure stage rotor 1 and the high-pressure stage rotor 2 are coaxially driven through the coupling 3, and the second adjusting gear 42 is configured to idle; under heating conditions, the coupling 3 is disengaged from the low-pressure stage rotor 1, the coupling 3 remains meshed with the high-pressure stage rotor 2, and the second adjusting gear 42 is configured to mesh with the outer periphery of the coupling 3.

[0040] Applying the above transmission scheme, under cooling conditions, power originates from the low-pressure-stage rotor 1, which begins to rotate under the drive of an external power source such as a motor. At this time, the low-pressure-stage rotor 1 and the high-pressure-stage rotor 2 are coaxially driven via the coupling 3. This means that the rotation of the low-pressure-stage rotor 1 is directly transmitted to the high-pressure-stage rotor 2 through the coupling 3, causing the high-pressure-stage rotor 2 to rotate synchronously with the low-pressure-stage rotor 1 at the same speed (due to coaxial transmission). Although the first adjustment gear 41 in the adjustment gear assembly 4 meshes with the outer periphery of the low-pressure-stage rotor 1 for transmission, the second adjustment gear 42 is configured to idle. That is to say, the first adjusting gear 41 will rotate with the rotation of the low-pressure stage rotor 1, but since the second adjusting gear 42 is idling, it will not produce additional power transmission impact on the entire transmission process. It only exists in the structure and does not participate in the actual power transmission to change the speed of the high-pressure stage rotor 2; since the high-pressure stage rotor 2 and the low-pressure stage rotor 1 rotate synchronously, the high-pressure stage exhaust volume at this time is mainly determined by the speed of the low-pressure stage rotor 1 and the design parameters of the compressor itself. Under this working condition, a relatively stable state is maintained to meet the system requirements under refrigeration conditions.

[0041] Using the above transmission scheme, when entering the heating mode, the first thing that happens is that the coupling 3 disengages from the low-pressure stage rotor 1, severing the direct transmission path between the low-pressure stage rotor 1 and the high-pressure stage rotor 2, which originally passed through the coupling 3. At this point, the adjusting gear assembly 4 comes into play. The first adjusting gear 41 continues to mesh with the outer circumference of the low-pressure stage rotor 1, and the rotation of the low-pressure stage rotor 1 drives the first adjusting gear 41. Because the first adjusting gear 41 and the second adjusting gear 42 are coaxially driven, the second adjusting gear 42 rotates with the first adjusting gear 41. Since the second adjusting gear 42 is configured to mesh with the outer circumference of the coupling 3, its rotation is transmitted to the high-pressure stage rotor 2 through the coupling 3. Due to the intervention of the adjusting gear assembly 4, the speed of the high-pressure stage rotor 2 is no longer the same as that of the low-pressure stage rotor 1, but is instead modified by the transmission ratio of the adjusting gear assembly 4. Specifically, the transmission ratio of the adjusting gear assembly 4 determines the speed variation of the high-pressure stage rotor 2 relative to the low-pressure stage rotor 1. By properly designing parameters such as the number of teeth of the first and second adjusting gears 41 and 42, the speed of the high-pressure stage rotor 2 can be precisely controlled. Since the exhaust volume of a screw compressor is proportional to its speed, when the speed of the high-pressure stage rotor 2 changes, the high-pressure stage exhaust volume also changes accordingly. By adjusting the high-pressure stage exhaust volume, the intermediate pressure can be matched to the theoretical intermediate pressure of the system under heating conditions.

[0042] In summary, the synchronous rotation between the low-pressure stage rotor 1, the coupling 3 and the high-pressure stage rotor 2 can be achieved under the cooling condition, and the speed of the high-pressure stage rotor 2 can be adjusted separately under the heating condition. In the process, the coupling 3 rotates synchronously with the high-pressure stage rotor 2, and the coupling 3 will not drive the low-pressure stage rotor 1 to rotate synchronously, thereby adjusting the pressure ratio distribution of each stage of the compressor, so as to achieve the theoretical best pressure ratio distribution under different working conditions, thereby improving the energy efficiency of the system.

[0043] From an overall structural perspective, applying this gear transmission device to a two-stage screw compressor can enhance the compressor's adaptability to different operating conditions. By changing the meshing transmission relationship between the high-pressure stage rotor 2, the low-pressure stage rotor 1, and the coupling 3, the gear transmission device can flexibly adjust the transmission mode under both cooling and heating conditions. Under cooling conditions, the simple and direct coaxial transmission of the coupling 3 ensures efficient and stable cooling. Under heating conditions, the transmission ratio is changed by adjusting the gear assembly 4, allowing the compressor to adapt to the different requirements of the heating condition for the high-pressure stage exhaust volume, thereby enhancing the compressor's adaptability to different operating conditions.

[0044] From an overall structural perspective, applying this gear transmission to a two-stage screw compressor allows for matching intermediate pressures. The theoretical intermediate pressure of the system varies under different operating conditions. By adjusting the high-pressure stage exhaust volume, the intermediate pressure can be brought closer to the theoretical system intermediate pressure. In heating mode, adjusting the speed of the high-pressure stage rotor 2 by adjusting gear assembly 4, and thus adjusting the high-pressure stage exhaust volume, allows the intermediate pressure to better match the theoretical value under heating conditions, thereby improving the energy efficiency and performance of the entire system.

[0045] From an overall structural perspective, applying this gear transmission to a two-stage screw compressor allows for simple adjustment of the high-pressure stage rotor 2's speed. Specifically, the adjustment gear assembly 4 is located on the same side of the low-pressure stage rotor 1, high-pressure stage rotor 2, and coupling 3. This layout makes the entire device relatively compact and facilitates installation and maintenance. Furthermore, adjustment of the high-pressure stage exhaust volume is achieved through simple meshing switching (engaging and disengaging coupling 3 with the low-pressure stage rotor 1) and the use of the adjustment gear assembly 4, avoiding the need for a complex mechanical structure and control system, and improving the reliability and cost-effectiveness of the device.

[0046] Considering the transmission scheme of the coupling 3 and the low-pressure stage rotor 1 and the high-pressure stage rotor 2 under the refrigeration condition, in the gear transmission device provided in the embodiment of the present application, the coupling 3 includes a first end shaft 31 and a second end shaft 32. Under the refrigeration condition, the first end shaft 31 extends into the first inner cavity 11 of the low-pressure stage rotor 1, and is meshed and connected to the first inner cavity 11 of the low-pressure stage rotor 1. The second end shaft 32 extends into the second inner cavity 21 of the high-pressure stage rotor 2, and is meshed and connected to the second inner cavity 21 of the high-pressure stage rotor 2.

[0047] In this way, the synchronous transmission scheme, in which the two end shafts of the coupling 3 extend into the high-pressure stage rotor 2 and the low-pressure stage rotor 1, respectively, can directly connect the low-pressure stage rotor 1 and the high-pressure stage rotor 2 via the coupling 3, resulting in a relatively compact structure. Furthermore, the meshing transmission method can achieve efficient power transmission and reduce power loss. Because the meshing transmission ensures close contact between the components, there is almost no slippage during the power transmission process, which can ensure that the power of the low-pressure stage rotor 1 is transmitted to the high-pressure stage rotor 2 to the maximum extent, thereby improving the overall operating efficiency of the compressor.

[0048] Furthermore, the stable meshing transmission connection ensures that under refrigeration conditions, the speed relationship between the low-pressure stage rotor 1 and the high-pressure stage rotor 2 always remains relatively fixed; this fixed speed relationship helps to maintain the pressure balance inside the compressor and the stability of the gas flow; for example, in a refrigeration system, a stable speed relationship can ensure that the compression process of the refrigerant in the compressor is stable, and there will be no problems such as unstable cooling capacity due to speed fluctuations, thereby improving the stability and reliability of the entire refrigeration system operation; it can facilitate the optimization design and control of the compressor according to different working conditions; for example, under refrigeration conditions, according to this transmission scheme, the compressor's exhaust volume, power consumption and other parameters can be accurately calculated, so as to better match the operating requirements of the refrigeration system.

[0049] Considering the specific meshing transmission scheme between the coupling 3 and the high-pressure stage rotor 2, in the gear transmission device provided in the embodiment of the present application, the second inner cavity 21 of the high-pressure stage rotor 2 includes a second meshing section 211 and a second cavity section 212 connected to the second meshing section 211. The second meshing section 211 is used for meshing transmission with the second end shaft 32 of the coupling 3. The second cavity section 212 has a piston mechanism 5, which is used to push the coupling 3 to move toward the direction of the low-pressure stage rotor 1.

[0050] This allows for transmission adjustment during operating mode switching. In cooling mode, coupling 3 meshes normally with both the low-pressure stage rotor 1 and the high-pressure stage rotor 2. When switching to heating mode, piston mechanism 5 comes into play. Piston mechanism 5 pushes coupling 3 toward the low-pressure stage rotor 1, gradually disengaging the coupling 3 from the low-pressure stage rotor 1. Because one end of coupling 3 is within the second inner cavity 21 of the high-pressure stage rotor 2, the piston mechanism 5 shifts the axial position of coupling 3, thereby altering its relative positional relationship with the low-pressure stage rotor 1 and changing the meshing state between the two. This design allows the compressor to flexibly adjust the transmission relationship between different operating modes, adapting to the torque transmission path requirements of different operating conditions. When switching from heating to cooling mode, piston mechanism 5 reverses its action (or relies on other reset mechanisms) to reset coupling 3, reengaging it with the low-pressure stage rotor 1 and restoring the transmission state for cooling mode, ensuring operability and stability during operating mode switching.

[0051] It should be pointed out that the presence of the piston mechanism 5 provides a means for accurately controlling the engagement and disengagement of the coupling 3 and the low-pressure stage rotor 1. By controlling the movement of the piston mechanism 5, the distance and speed of movement of the coupling 3 can be accurately controlled, thereby accurately achieving the switching of the transmission relationship. Compared with some methods that rely on external forces or simple mechanical structures to achieve engagement and disengagement, this has higher precision and reliability. For example, in some application scenarios with high requirements for working condition switching, the transmission relationship can be adjusted quickly and accurately to avoid compressor performance degradation or failure due to inaccurate switching.

[0052] Furthermore, due to the structural design of the second meshing section 211 and the second cavity section 212, the installation and action positions of the piston mechanism 5 are more reasonable; the second meshing section 211 ensures a stable connection between the coupling 3 and the high-pressure stage rotor 2 during normal transmission, while the second cavity section 212 provides installation space and action space for the piston mechanism 5. The two cooperate with each other to make the structure of the entire transmission system more compact and reasonable.

[0053] By using the gear transmission device of the embodiment of the present application, which can improve the adaptability of the compressor to operating conditions, in heating conditions, after the coupling 3 is disengaged from the low-pressure stage rotor 1, different torque transmission paths can be achieved through other transmission components (such as the adjustment gear assembly 4 mentioned above) to adjust the high-pressure stage exhaust volume so that the intermediate pressure matches the theoretical value under heating conditions; while in cooling conditions, the coupling 3 engages normally with the low-pressure stage rotor 1 and the high-pressure stage rotor 2, ensuring efficient operation under cooling conditions. Through this flexible transmission relationship adjustment, the compressor can maintain good performance under different operating conditions, improving its application range and practicality.

[0054] In addition, the design of the piston mechanism 5 can also buffer the impact force during the transmission process to a certain extent; when the working conditions are switched, the movement of the piston mechanism 5 can absorb part of the impact force caused by the change in the transmission relationship, reduce damage to the internal components of the compressor, extend the service life of the compressor, and also help reduce vibration and noise during operation.

[0055] Considering the specific meshing transmission scheme of the coupling 3 and the low-pressure stage rotor 1, in the gear transmission device provided in the embodiment of the present application, the first inner cavity 11 of the low-pressure stage rotor 1 includes a first meshing section 111 and a first cavity section 112 connected to the first meshing section 111. The first meshing section 111 is used for meshing transmission with the first end shaft 31 of the coupling 3. The first cavity section 112 has a thrust member 6, which is used to limit the maximum displacement of the coupling 3 toward the low-pressure stage rotor 1.

[0056] In this way, transmission stability can be ensured, component integrity can be protected, and working condition switching and system control can be facilitated.

[0057] Regarding ensuring transmission stability, first, the engagement depth can be precisely controlled. Under refrigeration conditions, the first end shaft 31 of the coupling 3 meshes with the first meshing section 111 of the low-pressure stage rotor 1 to achieve power transmission from the low-pressure stage rotor 1 to the high-pressure stage rotor 2. The presence of the thrust member 6 precisely controls the maximum displacement of the first end shaft 31 of the coupling 3 when inserted into the first inner cavity 11, ensuring that the first end shaft 31 and the first meshing section 111 are at the optimal engagement depth. If the engagement depth is too shallow, it may cause slippage during transmission, reducing power transmission efficiency and even causing separation between the coupling 3 and the low-pressure stage rotor 1, affecting the normal operation of the compressor. The thrust member 6 limits the maximum displacement, preventing this from occurring and ensuring stable power transmission. Second, it can maintain stable torque transmission. A stable engagement depth helps maintain stable torque transmission. During compressor operation, stable torque transmission is crucial to ensuring compressor performance. The displacement of the coupling 3 is limited by the thrust member 6, so that the contact area and contact force between the first end shaft 31 and the first meshing section 111 remain relatively stable, thereby ensuring that the torque can be reliably transmitted from the low-pressure stage rotor 1 to the coupling 3 and then to the high-pressure stage rotor 2, thereby improving the stability and reliability of the entire transmission system.

[0058] Regarding component integrity protection, first, it prevents damage from over-insertion. During operating mode switching or compressor operation, coupling 3 may over-move toward the low-pressure stage rotor 1. Without the restraining force of thrust member 6, coupling 3's first end shaft 31 may over-insert into first inner cavity 11, causing damage to the walls of first inner cavity 11, first end shaft 31 itself, and associated meshing teeth. The thrust member 6 promptly prevents excessive displacement of coupling 3, preventing component damage caused by over-insertion. This extends the service life of key components, such as the low-pressure stage rotor 1 and coupling 3, and reduces compressor maintenance costs and failure rates. Second, it reduces impact and wear. When coupling 3 approaches maximum displacement during movement, thrust member 6 acts as a buffer, reducing the impact between coupling 3 and low-pressure stage rotor 1. This buffering effect helps reduce wear between components, particularly during frequent operating mode switching, significantly reducing the likelihood of component performance degradation and failures caused by impact and wear.

[0059] Regarding operating mode switching and system control, first, it ensures the accuracy of operating mode switching. When switching between cooling and heating modes, coupling 3 needs to engage or disengage with the low-pressure stage rotor 1. The presence of thrust member 6 provides a clear position reference for this operation, allowing coupling 3 to accurately move to the appropriate position during the operating mode switching process, ensuring the accuracy of the engagement and disengagement operations. For example, when switching from heating mode to cooling mode, coupling 3 needs to re-engage with the low-pressure stage rotor 1. Thrust member 6 can help coupling 3 quickly and accurately reach the correct engagement position, improving the efficiency and reliability of operating mode switching. Second, it facilitates overall system control. For the control of the entire compressor system, the presence of thrust member 6 makes the displacement of coupling 3 predictable and controllable. Based on the position information defined by thrust member 6, the control system can better adjust the movement of components such as piston mechanism 5, achieving precise control of the position and state of coupling 3, thereby optimizing the operating performance of the compressor under different operating conditions.

[0060] Considering the specific transmission scheme between the low-pressure stage rotor 1, the high-pressure stage rotor 2, the coupling 3 and the adjusting gear assembly 4, in the gear transmission device provided in the embodiment of the present application, the shaft end of the low-pressure stage rotor 1 has a first toothed shaft section 12, the shaft end of the high-pressure stage rotor 2 has a second toothed shaft section 22, and the coupling 3 has a third toothed shaft section 33 on the periphery; the first adjusting gear 41 and the second adjusting gear 42 in the adjusting gear assembly 4 are coaxial and spaced apart, and the first adjusting gear 41 is engaged with the first toothed shaft section 12 for transmission; under the heating condition, the coupling 3 moves to the position of the second adjusting gear 42 and is engaged with the second adjusting gear 42 for transmission, and the first meshing section 111 of the first inner cavity 11 in the low-pressure stage rotor 1 is disengaged from the first end shaft 31 in the coupling 3.

[0061] First, regarding the independent transmission path construction for the heating working condition, in the heating working condition, the coupling 3 moves to engage with the second adjusting gear 42 for transmission, while the low-pressure stage rotor 1 disengages from the coupling 3. At this time, the power transmission path of the low-pressure stage rotor 1 changes: the low-pressure stage rotor 1 engages with the first adjusting gear 41 through the first toothed shaft section 12 at the end of the shaft. Since the first adjusting gear 41 is coaxial with the second adjusting gear 42, the second adjusting gear 42 engages with the third toothed shaft section 33 on the outer periphery of the coupling 3, and finally transmits power to the second toothed shaft section 22 of the high-pressure stage rotor 2. This change in the transmission path makes the high-pressure stage rotor 2 no longer maintain a direct coaxial speed relationship with the low-pressure stage rotor 1, but can flexibly adjust the speed of the high-pressure stage rotor 2 by adjusting the gear ratio of the gear assembly 4. For example, if the first adjusting gear 41 has a large number of teeth and the second adjusting gear 42 has a small number of teeth, when the speed of the low-pressure stage rotor 1 is constant, the speed of the high-pressure stage rotor 2 will decrease, thereby reducing the high-pressure stage exhaust volume to match the theoretical intermediate pressure under the heating condition, thereby optimizing the system energy efficiency. Secondly, regarding the efficient direct transmission under refrigeration conditions, under refrigeration conditions, the coupling 3 directly engages with the low-pressure stage rotor 1 and the high-pressure stage rotor 2 for transmission. At this time, the power of the low-pressure stage rotor 1 is directly and efficiently transmitted to the high-pressure stage rotor 2 through the coupling 3, and the two maintain coaxial rotation at the same speed. This direct transmission method reduces the intermediate transmission links and reduces transmission losses. It is suitable for the demand for stable cooling capacity under refrigeration conditions and ensures the efficient operation of the compressor under refrigeration conditions. Through the differentiated design of the transmission path under two different working conditions, the compressor can maintain good performance under different working conditions, improving the overall adaptability to working conditions.

[0062] At the same time, it also enables precise adjustment of the high-pressure stage exhaust volume. First, the introduction of the adjusting gear assembly 4, based on the flexible adjustment of the gear ratio, enables precise adjustment of the high-pressure stage exhaust volume. Under heating conditions, the meshing transmission between the first adjusting gear 41 and the first toothed shaft segment 12, and the second adjusting gear 42 and the third toothed shaft segment 33, utilizes the principle of gear ratio to adjust the speed of the high-pressure stage rotor 2 according to actual operating conditions. Because the exhaust volume of a screw compressor is proportional to the speed, adjusting the speed of the high-pressure stage rotor 2 can achieve adjustment of the high-pressure stage exhaust volume. For example, when the system detects that the intermediate pressure under heating conditions is higher than the theoretical value, the adjusting gear assembly 4 can be adjusted (e.g., by replacing an adjusting gear with a different number of teeth) to increase the speed of the high-pressure stage rotor 2 and increase the high-pressure stage exhaust volume, thereby reducing the intermediate pressure to approach the theoretical optimal value. Conversely, when the intermediate pressure is lower than the theoretical value, the speed of the high-pressure stage rotor 2 is reduced, reducing the high-pressure stage exhaust volume and increasing the intermediate pressure. Ultimately, the intermediate pressure is precisely matched to the system's theoretical intermediate pressure, improving system energy efficiency. Secondly, it can achieve adaptive adjustment for dual working conditions. Since the adjustment gear assembly 4 can flexibly adjust the high-pressure stage exhaust volume, the gear transmission device can effectively adapt to both cooling and heating working conditions. In cooling working conditions, there is no need for the adjustment gear assembly 4 to participate in the adjustment, and direct transmission ensures efficient cooling; in heating working conditions, the adjustment gear assembly 4 plays a role, and the high-pressure stage exhaust volume is adjusted in a targeted manner according to the characteristics and requirements of the heating working conditions, ensuring that the compressor can operate efficiently in both working conditions, meeting the use requirements under different working conditions, and expanding the application range of the compressor.

[0063] Furthermore, the stability and reliability of the system structure can be enhanced. First, the transmission components are clearly positioned and matched. The low-pressure stage rotor 1, the high-pressure stage rotor 2, the coupling 3 and the adjusting gear assembly 4 are connected and transmitted through specific toothed shaft segments and meshing relationships. The positioning and matching of each component are clear. For example, the meshing of the first adjusting gear 41 with the first toothed shaft segment 12, the meshing of the second adjusting gear 42 with the third toothed shaft segment 33, and the connection and disconnection of the coupling 3 with each component under different working conditions are all precisely designed and specified. This clear structural relationship ensures that power can be stably transmitted between the components during the transmission process, reducing vibration, noise and wear caused by improper matching of components. At the same time, during the working mode switching process, the movement of the coupling 3 and the change of the meshing state also have clear paths and position references, reducing the risk of failure during the working mode switching process and enhancing the stability of the system structure. Secondly, through a reasonably designed transmission scheme, the high efficiency of power transmission can be guaranteed under different working conditions. Direct transmission in cooling mode reduces energy loss in intermediate links. In heating mode, despite the addition of an adjustable gear assembly 4, precise gear meshing design keeps energy loss to a minimum. Furthermore, the stable meshing between components helps reduce additional energy loss caused by factors such as slippage and impact, improving the overall system's energy efficiency and ensuring the compressor's reliability over extended periods of operation.

[0064] Considering the transmission ratio scheme of the overall device, in the gear transmission device provided in the embodiment of the present application, the number of teeth of the second adjusting gear 42 is smaller than the number of teeth of the first adjusting gear 41 , and the number of teeth of the first toothed shaft segment 12 is smaller than the number of teeth of the third toothed shaft segment 33 .

[0065] This allows for reduced speed and increased efficiency of the high-pressure stage rotor 2 under heating conditions. First, based on the principle of gear ratio reduction, in gear transmission, the transmission ratio i is equal to the ratio of the number of teeth z2 on the driven gear to the number of teeth z1 on the driving gear (i=z2 / z1). When i>1, it is a reduced speed transmission. Under heating conditions, the low-pressure stage rotor 1 drives the first adjustment gear 41 via the first toothed shaft section 12. Since the second adjustment gear 42 is coaxial with the first adjustment gear 41, it in turn drives the third toothed shaft section 33 of the coupling 3. Given that the second adjustment gear 42 has fewer teeth than the first adjustment gear 41, and the first toothed shaft section 12 has fewer teeth than the third toothed shaft section 33, this creates a multi-stage speed reduction effect across the entire transmission path. For example, assuming the first adjusting gear 41 has 20 teeth, the second adjusting gear 42 has 15 teeth, the first toothed shaft segment 12 has 30 teeth, and the third toothed shaft segment 33 has 45 teeth, then the total transmission ratio i from the first toothed shaft segment 12 to the third toothed shaft segment 33 is (z1) / (z1)*(z3 / z2). This means the speed of the high-pressure stage rotor 2 is only half that of the low-pressure stage rotor 1. Secondly, this system can optimize energy efficiency for heating conditions. The exhaust volume of a screw compressor is proportional to its speed. Reducing the speed of the high-pressure stage rotor 2 means a reduction in high-pressure stage exhaust volume. Under heating conditions, the required intermediate pressure of the system differs from that under cooling conditions. By reducing the high-pressure stage exhaust volume, the intermediate pressure can be brought closer to the theoretical maximum system efficiency value for heating conditions. Reducing the speed of the high-pressure stage rotor 2 also reduces its operating power consumption, avoiding problems such as an unreasonable compression ratio and excessively high exhaust temperature caused by excessively high speed, thereby improving the energy efficiency and stability of the entire heating system.

[0066] At the same time, it optimizes power distribution and torque transmission under dual operating conditions. First, it enables direct and efficient power transmission in cooling mode. In cooling mode, coupling 3 directly connects the low-pressure stage rotor 1 and the high-pressure stage rotor 2, and the regulating gear assembly 4 does not participate in power transmission. Since the first and third geared shaft segments 12 and 33 do not directly participate in the transmission under these conditions, the difference in their tooth counts (the first geared shaft segment 12 has fewer teeth than the third geared shaft segment 33) does not affect cooling operation. Power from the low-pressure stage rotor 1 can be directly and efficiently transmitted to the high-pressure stage rotor 2, maintaining the same speed for both rotors. This meets the requirement for stable cooling output under cooling conditions and achieves efficient operation in these conditions. Second, it enables torque amplification and stable transmission in heating mode. In heating mode, the multi-stage gear transmission not only reduces speed but also amplifies torque (according to the law of conservation of energy, power P = T * w. Torque T increases during speed reduction, where w is the angular velocity). The larger number of teeth on the first toothed shaft section 12 enables it to withstand the higher torque output by the low-pressure stage rotor 1. The larger number of teeth on the third toothed shaft section 33, when engaged with the second adjustment gear 42, stably transmits the amplified torque to the high-pressure stage rotor 2. This optimized torque transmission design ensures that even when the speed of the high-pressure stage rotor 2 decreases under heating conditions, sufficient torque is available to maintain a stable compression process, avoiding problems such as reduced compression efficiency or unstable operation due to insufficient torque.

[0067] Furthermore, it can also enhance the adaptability of the system to working conditions and the compactness of the structure. First, it can accurately match the dual working conditions requirements. By setting the number of teeth of the second adjusting gear 42 to be smaller than the number of teeth of the first adjusting gear 41, and the number of teeth of the first toothed shaft section 12 to be smaller than the number of teeth of the third toothed shaft section 33, a unique transmission ratio scheme is formed. This scheme can accurately match the operating requirements of both cooling and heating working conditions. Maintaining efficient direct transmission under cooling conditions and achieving targeted speed reduction and pressure regulation under heating conditions allows the compressor to maintain good performance under different working conditions, greatly enhancing the system's adaptability to different working conditions and broadening the application scenarios of the compressor. Secondly, a compact structural design is obtained. The transmission ratio scheme is based on the principle of gear transmission. By rationally designing the number of teeth of each gear and toothed shaft section, while achieving complex working condition adjustment functions, there is no need to add too many complex transmission components or large speed change mechanisms. Compared with other complex speed change methods (such as planetary gear speed change), this design makes the entire gear transmission device more compact, occupies less space, is easy to install and integrate into a single-unit two-stage screw compressor system, and also reduces manufacturing and maintenance costs.

[0068] Considering the meshing structure 7 scheme of the meshing transmission, in the gear transmission device provided in the embodiment of the present application, the meshing structure 7 at each meshing transmission position adopts a spline structure.

[0069] In this way, each meshing transmission position adopts a spline-type structure, which has many significant logical effects. From the perspective of transmission stability, the spline structure can evenly transmit torque through the cooperation of multiple key teeth and keyways. Compared with ordinary flat key connections, it can effectively avoid component wear and loosening caused by uneven force, and ensure the stable and reliable power transmission between the low-pressure stage rotor 1, the high-pressure stage rotor 2, the coupling 3 and the adjustment gear assembly 4 during the operation of the compressor, reducing vibration and noise. In terms of transmission efficiency, the spline tooth side matching clearance is small, which can minimize energy loss during power transmission, making the transmission between the components more efficient, and helping to improve the energy efficiency of the entire compressor system. From the perspective of assembly and maintenance, the spline structure has good centering and guiding properties, which facilitates the installation and disassembly of components, reducing the difficulty and time cost of assembly; at the same time, its high structural strength and good wear resistance can extend the service life of components and reduce the maintenance frequency and repair costs caused by damage to the meshing structure 7. In addition, when the working conditions are switched, the spline structure can ensure that the coupling 3 and each component can quickly and accurately engage and disengage, and cooperate with other transmission components to achieve efficient switching of different transmission paths under cooling and heating conditions, thereby enhancing the adaptability and responsiveness of the compressor to different working conditions, thereby ensuring the stable and efficient operation of the entire gear transmission device under various working conditions.

[0070] When the gear transmission device according to the embodiment of the present application is applied, after the exhaust volumes of the two-stage screw rotors are determined, the intermediate pressure constant value can be determined through iterative calculation. Since the rotor exhaust volume corresponds one-to-one with the rotational speed, and the rotational speeds of the high-pressure and low-pressure stage rotors 1 directly connected by the coupling 3 are equal, it is impossible to adjust the rotational speed of each stage separately. However, the low-pressure stage rotor 1 and the high-pressure stage rotor 2 adopt a new transmission connection scheme with the new coupling 3. The two ends of the coupling 3 have threaded or gear-shaped torque-transmitting structures on the shafts. The two shafts are inserted into the internal cavities (with corresponding transmission structures) of the two-stage rotors to achieve torque transmission between the two-stage rotors. Inside the rotors, in addition to the torque-transmitting structure, there will be cavities with a larger inner diameter (i.e., the first cavity section 112 and the second cavity section 212), and there is no transmission structure in the cavities. A piston mechanism 5 is provided in the cavity of the high-pressure stage rotor 2 to push the coupling 3 towards the low-pressure stage rotor 1; a thrust block is provided in the cavity of the low-pressure stage rotor 1 to limit the position of the coupling 3; there is a toothed shaft section a with the number of teeth Z1 at the end of the shaft of the low-pressure stage rotor 1. There is also an adjusting gear rotating shaft beside the coupling 3. This shaft is fixed separately, and there are also two toothed shaft sections on its shaft. The toothed shaft section b (with the number of teeth Z2) near the low-pressure stage rotor 1 end meshes with the toothed shaft section on the shaft of the low-pressure stage rotor 1, and the toothed shaft section c (with the number of teeth Z3) near the high-pressure stage rotor 2 end does not mesh with other shaft sections in the initial state and is in an idle state. Similarly, the new coupling 3 also has a toothed shaft section d with the number of teeth Z4 in the middle section. Among them, Z3 < Z2, and Z1 is slightly less than Z4, that is, under the heating condition, the rotational speed of the high-pressure stage rotor 2 decreases and the high-pressure stage displacement decreases. This is because the condensation temperature under the heating condition is higher, the corresponding optimal intermediate pressure is higher, the gas density in the intermediate cavity is greater, and the volume under the same mass is smaller, so the high-pressure stage displacement needs to decrease.

[0071] In the initial state, the system operating condition is the refrigeration condition required by the user. The low-pressure stage rotor 1 is配合 with the coupling 3 through the internal cavity transmission structure. The coupling 3 meshes with the internal transmission structure of the high-pressure stage rotor 2 cavity, driving the high-pressure stage rotor 2 to rotate. At this time, the shaft section b of the adjusting gear rotating shaft meshes with the shaft section a of the low-pressure stage rotor 1, driving the shaft section c to rotate idly. When the system operating condition needs to be converted to the heating condition required by the user, the high-pressure oil (high-pressure stage exhaust pressure) enters the right side of the cavity piston of the high-pressure stage rotor 2 through the oil supply hole of the high-pressure stage rotor 2. The oil hole of the low-pressure stage rotor 1 is connected to the low-pressure stage suction to increase the pressure difference between the two sections, pushing the coupling 3 to move towards the low-pressure stage. When the coupling 3 moves to the internal limit of the shaft, the shaft section c and the shaft section d of the coupling 3 are fully meshed, and the inside of the low-pressure stage rotor 1 cavity is disengaged from the coupling 3. At this time, the transmission between the low-pressure stage rotor 1 and the high-pressure stage rotor 2 is realized by the adjusting gear shaft. When switching from the heating condition to the refrigeration condition, the right side of the cavity piston of the high-pressure stage rotor 2 is connected to the low-pressure stage suction end. The oil hole of the low-pressure stage rotor 1 sucks in the high-pressure oil, and the gas pressure difference pushes the coupling 3 to move towards the high-pressure stage, restoring to the initial state. It should be noted that when the shaft section d of the coupling 3 just starts to mesh with the shaft section c of the gear adjusting shaft, the internal meshing tooth section of the low-pressure stage rotor 1 needs to be disengaged, otherwise the rotor will be stuck.

[0072] Next, analyze the rotational speed of the high-pressure stage rotor 2 under the two operating conditions. In the initial state, the low-pressure stage and the high-pressure stage are connected by the coupling 3, so V low = V high. In the heating condition, according to the gear transmission ratio V1*Z1 = V2*Z2, it can be gradually deduced that V high = V low * Z1 / Z2 * Z3 / Z4. Under the same module, the more teeth, the larger the diameter. It can be seen from the figure that Z3 < Z2 and Z1 is slightly larger than Z4. That is, in the heating condition, the rotational speed of the high-pressure stage rotor 2 decreases and the high-pressure stage displacement decreases. This is because the condensation temperature in the heating condition is higher, the corresponding optimal intermediate pressure is higher, the gas density in the intermediate cavity is greater, and the volume under the same mass is smaller, so the high-pressure stage displacement needs to decrease.

[0073] Additionally, the meshing structure 7 is a structure similar to a spline, and the spline types include but are not limited to rectangle, involute, triangle, etc.

[0074] The embodiment of the present application further provides a two-stage screw compressor, including the above-mentioned gear transmission device.

[0075] Specifically, a two-stage screw compressor consists of a casing, core compression components, a power transmission system, and auxiliary components. The casing serves as the outer frame of the entire compressor, providing protection and support for the internal components, protecting them from dust and water, and securing and supporting the internal components, ensuring the compressor remains stable during operation. The enclosed space within it provides a space for the refrigerant gas compression process while also effectively reducing the transmission of operating noise. The core compression components include a low-pressure screw rotor and a high-pressure screw rotor, each mounted on a corresponding rotor shaft. The two rotors work together within the casing. The rotors have a special helical tooth profile, and as the rotors rotate, the volume between the teeth continuously changes, enabling the intake, compression, and discharge of the refrigerant gas. The power transmission system is a key component of the two-stage screw compressor and includes a low-pressure rotor shaft 1, a high-pressure rotor shaft 2, a coupling 3, and an adjustment gear assembly 4. A first toothed shaft section 12 is provided at the end of the shaft of the low-pressure stage rotor 1, and the first inner cavity 11 inside it is divided into a first meshing section 111 and a first cavity section 112. The first meshing section 111 is used to mesh with the first end shaft 31 of the coupling 3 for transmission, and the first cavity section 112 is provided with a thrust piece 6; a second toothed shaft section 22 is provided at the end of the shaft of the high-pressure stage rotor 2, and its second inner cavity 21 includes a second meshing section 211 and a second cavity section 212. The second meshing section 211 is used to mesh with the second end shaft 32 of the coupling 3, and the second cavity section 212 is equipped with a piston mechanism 5. The coupling 3 has a first end shaft 31 and a second end shaft 32, connected to the low-pressure stage rotor 1 and the high-pressure stage rotor 2, respectively. The regulating gear assembly 4 consists of a first regulating gear 41 and a second regulating gear 42, which are coaxial and spaced apart. The first regulating gear 41 meshes with the first toothed shaft section 12 of the low-pressure stage rotor 1. Auxiliary components include an intake end seat, an exhaust end seat, an intermediate air supply device, and a slide valve. The intake end seat is used to guide low-temperature, low-pressure refrigerant gas into the low-pressure stage screw rotor; the exhaust end seat discharges high-temperature, high-pressure refrigerant gas compressed by the high-pressure stage screw rotor. The intermediate air supply device replenishes refrigerant gas to the intermediate cavity during the compression process, helping to improve the performance and efficiency of the compressor. The slide valve adjusts the volume ratio of each rotor stage to suit different operating conditions, ensuring efficient operation of the compressor under various operating conditions.

[0076] Applying the aforementioned gear transmission device to a two-stage screw compressor can enhance the adaptability to working conditions. When the working conditions change, it is difficult for traditional two-stage screw compressors to take into account efficient operation under different working conditions. After applying this gear transmission device, under refrigeration conditions, the coupling 3 directly connects the low-pressure stage rotor 1 and the high-pressure stage rotor 2 to achieve coaxial transmission, ensuring the efficiency and stability of the refrigeration process; under heating conditions, the transmission path is changed by adjusting the gear assembly 4, so that the speed of the high-pressure stage rotor 2 changes, and then the high-pressure stage exhaust volume is adjusted to meet the needs of the heating conditions. This flexible transmission mode switching enables the two-stage screw compressor to maintain good performance in a variety of working conditions such as cooling and heating, significantly enhancing its adaptability to different working conditions.

[0077] Applying the aforementioned gear transmission to a two-stage screw compressor can improve system energy efficiency. During the two-stage compression process, intermediate pressure significantly impacts system efficiency. System efficiency is highest when the intermediate pressure reaches the square root of (evaporating pressure * condensing pressure). This gear transmission adjusts the high-pressure stage exhaust volume based on operating conditions by adjusting the speed of the high-pressure stage rotor 2, thereby bringing the intermediate pressure closer to the theoretical optimal value. This effectively improves system energy efficiency and reduces energy consumption in both cooling and heating conditions, significantly saving operating costs compared to traditional compressors and aligning with the trend toward energy conservation and environmental protection.

[0078] Applying the aforementioned gear transmission to a two-stage screw compressor can improve operational stability and reliability. The gear transmission utilizes a spline-type meshing structure 7, which evenly transmits torque, reduces wear and looseness between components, and reduces vibration and noise during operation, thereby improving transmission stability. Furthermore, the thrust member 6 and piston mechanism 5 within the device precisely control the displacement of the coupling 3, ensuring accurate adjustment of the transmission relationship during operating mode switching and avoiding transmission failures. This significantly improves the overall operational stability and reliability of the two-stage screw compressor, reduces maintenance frequency and repair costs, and extends the compressor's service life.

[0079] Applying the aforementioned gear transmission to a two-stage screw compressor allows for structural optimization and compactness. The ingenious design of this gear transmission allows for complex operating condition adjustment while maintaining overall structural compactness. Compared to traditional transmission structures, this device eliminates the need for excessively complex components, resulting in a rational layout of components and a smaller footprint. This not only facilitates the miniaturization of compressor design and production, but also reduces manufacturing complexity and costs, improving the product's market competitiveness and providing strong support for the further development and application of two-stage screw compressors.

[0080] The embodiment of the present application also provides an air conditioner, including the above-mentioned two-stage screw compressor, which can achieve all the effects of the above-mentioned two-stage screw compressor and will not be described in detail here.

[0081] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain" and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0082] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0083] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A gear transmission device, characterized in that: The gear transmission device comprises: Low-pressure stage rotor; High pressure stage rotor; a coupling coaxially connected between the low-pressure stage rotor and the high-pressure stage rotor; an adjusting gear assembly located on the same side of the low-pressure stage rotor, the high-pressure stage rotor, and the coupling, the adjusting gear assembly comprising a first adjusting gear and a second adjusting gear coaxially driven with the first adjusting gear, the first adjusting gear meshing with the outer periphery of the low-pressure stage rotor; Under refrigeration conditions, the low-pressure stage rotor and the high-pressure stage rotor are coaxially driven via the coupling, and the second adjusting gear is configured to idle; Under heating conditions, the coupling is disengaged from the low-pressure stage rotor, and the coupling maintains meshing transmission with the high-pressure stage rotor, and the second adjusting gear is configured to mesh transmission with the outer periphery of the coupling.

2. The gear transmission device according to claim 1, characterized in that: The coupling includes a first end shaft and a second end shaft. Under the refrigeration working condition, the first end shaft extends into the first inner cavity of the low-pressure stage rotor and is meshed and connected to the first inner cavity of the low-pressure stage rotor. The second end shaft extends into the second inner cavity of the high-pressure stage rotor and is meshed and connected to the second inner cavity of the high-pressure stage rotor.

3. The gear transmission device according to claim 2, characterized in that: The second inner cavity of the high-pressure stage rotor includes a second meshing section and a second cavity section connected to the second meshing section, the second meshing section is used to engage and transmit with the second end shaft of the coupling, and the second cavity section has a piston mechanism, and the piston mechanism is used to push the coupling to move toward the direction of the low-pressure stage rotor.

4. The gear transmission device according to claim 2, characterized in that: The first inner cavity of the low-pressure stage rotor includes a first meshing section and a first cavity section connected to the first meshing section, the first meshing section is used to mesh with the first end shaft of the coupling for transmission, and the first cavity section has a thrust member, which is used to limit the maximum displacement of the coupling toward the low-pressure stage rotor.

5. The gear transmission device according to claim 4, characterized in that: The shaft end of the low-pressure stage rotor has a first toothed shaft section; the coupling has a third toothed shaft section on the outer periphery; the first adjusting gear and the second adjusting gear in the adjusting gear assembly are coaxial and spaced apart, and the first adjusting gear is meshed with the first toothed shaft section for transmission; Under the heating condition, the coupling moves to the second adjusting gear position so that the third toothed shaft section is engaged with the second adjusting gear for transmission, and the first engaging section of the first inner cavity in the low-pressure stage rotor is disengaged from the first end shaft in the coupling.

6. The gear transmission device according to claim 1, characterized in that: The number of teeth of the second adjusting gear is smaller than the number of teeth of the first adjusting gear.

7. The gear transmission device according to claim 5, characterized in that: The number of teeth of the first toothed shaft segment is smaller than the number of teeth of the third toothed shaft segment.

8. The gear transmission device according to claim 1, characterized in that: The meshing structures used in each meshing transmission position all adopt a spline structure.

9. A two-stage screw compressor, characterized in that: The invention comprises a gear transmission device according to any one of claims 1 to 8.

10. An air conditioner, characterized in that: Comprising the two-stage screw compressor according to claim 9.

Images