A screw compressor structure with a large range of adjustable volume ratio

Abstract

The utility model relates to a screw compressor structure of large range adjustable content volume ratio, including the worm setting in the casing, the step motor of input end magnetic coupling connection with the worm is installed on the casing, the space perpendicular interlaced state of the axis with the worm is rotatably connected with the lead screw in the casing, a section of the lead screw is fixed with the worm wheel engaged with the worm, the turbine worm changes the rotation transmission direction through the interlaced mode, the slide valve group that can move in the slide valve hole axially is arranged in the slide valve hole of casing, another section of the lead screw is screwed with the slide valve group, and the slide valve group linear motion is driven through the rotation conversion linear motion mode between the screw rod and the slide valve group. This structure not only reduces the space requirement on the axial direction of semi-closed screw compressor, but also helps to adjust the content volume ratio in a large range.

Description

Technical Field

[0001] This utility model relates to a screw compressor structure with a wide range of adjustable internal volume ratio. Background Technology

[0002] Due to the uncertainties in refrigerant temperature and pressure characteristics and customer operating conditions, refrigeration systems often exhibit different pressure ratios under different operating conditions. Therefore, compressors with a fixed pressure ratio often experience undercompression or overcompression. Both undercompression and overcompression processes result in wasted power consumption, increased vibration and noise, and other problems.

[0003] Currently, semi-hermetic screw compressors, due to their built-in motors and very compact space, cannot accommodate a volume ratio adjustment structure as directly as open-type screw compressors. Therefore, there is an urgent need to develop a volume ratio adjustment structure suitable for wide-range adjustment in semi-hermetic screw compressors. Utility Model Content

[0004] The purpose of this invention is to provide a screw compressor structure with a wide range of adjustable internal volume ratio. This structure not only reduces the axial space requirement of a semi-hermetic screw compressor, but also facilitates a wide range of adjustment of the internal volume ratio.

[0005] The technical solution of this utility model is as follows: a screw compressor structure with a wide range of adjustable internal volume ratio, including a worm gear disposed in a housing, a stepper motor magnetically coupled to the input end of the worm gear mounted on the housing, a lead screw rotatably connected to the axis of the worm gear in a spatially perpendicular manner, a section of the lead screw fixed with a worm wheel meshing with the worm gear, the worm gear changing the direction of rotation transmission through an interleaved manner, a slide valve assembly capable of axial movement within the slide valve hole of the housing, the other section of the lead screw threadedly connected to the slide valve assembly, and the lead screw driving the slide valve assembly to linear motion by rotating into linear motion.

[0006] Furthermore, the stepper motor is mounted on a bracket base, and the base is sealed and mounted on the housing.

[0007] Furthermore, the output shaft of the stepper motor is magnetically coupled to the input end of the worm gear via two coupled planar magnetic couplings, one of which is disposed in the base and fixedly connected to the input end of the worm gear.

[0008] Furthermore, a bearing seat A with a shoulder is installed inside the housing and is positioned between the housing and the base. A sliding bearing A is installed on the bearing seat A. A sliding bearing B is installed inside the housing. The worm gear is installed between the sliding bearing A and the sliding bearing B.

[0009] Furthermore, a sliding bearing C and a sliding bearing D are disposed above the worm gear inside the housing, a section of the lead screw is mounted on the sliding bearing C and the sliding bearing D, and the worm wheel is disposed between the sliding bearing C and the sliding bearing D.

[0010] Furthermore, a bearing housing B is fixed inside the housing, and the sliding bearing D is installed inside the bearing housing B.

[0011] Furthermore, the clearance between the lead screw and the sliding bearings C and D is 0.05 mm to 0.1 mm, which is smaller than the side clearance between the worm gear and the worm.

[0012] Furthermore, the valve assembly consists of a Vi valve and an adjustable valve connected together, and another section of the lead screw is screwed to a lead screw nut installed inside the Vi valve.

[0013] Furthermore, the Vi slide valve has a guide groove axially formed on its side, and a pin hole is drilled on the housing. A positioning pin with one end extending into the guide groove is installed in the pin hole, so that the rotational motion of the lead screw is converted into the linear motion of the Vi slide valve along the axial direction.

[0014] Furthermore, worm gear drives can be replaced by helical gear drives, staggered shaft helical gear drives, rack and pinion drives, or bevel gear drives.

[0015] Furthermore, the slide valve assembly is machined with an internal thread that connects to the lead screw.

[0016] Furthermore, the transmission method for converting the rotation between the lead screw and the slide valve assembly into linear motion includes sliding lead screw nut transmission, ball screw nut transmission, or screw nut transmission.

[0017] Furthermore, the adjustable slide valve is provided with a relief recess on the end near the Vi slide valve to avoid the other end of the lead screw.

[0018] Compared with the prior art, the present invention has the following advantages: 1. The worm gear transmission structure significantly reduces the axial space requirement, overcoming the limitations of the axial space constraints of a built-in motor. Due to this compact volume ratio adjustment method, a wide volume ratio range can be achieved within a limited space, and fully automatic stepless adjustment is possible, ranging from 2.0 to 4.6. This essentially covers the common operating conditions of refrigeration systems.

[0019] 2. The torque transmission method using a planar magnetic coupling transforms the original dynamic seal into a static seal, eliminating leakage problems. In addition, the planar magnetic coupling allows slippage during torque transmission, greatly protecting mechanical components and the stepper motor, preventing damage to mechanical components and overload burnout of the stepper motor.

[0020] 3. An adjustable internal volume ratio structure is installed at the bottom of the housing, so that the entire device can be fully lubricated by the lubricating oil deposited inside the compressor, preventing wear on moving parts.

[0021] 4. The bottom diameter of the worm gear profile should be larger than the inner diameter of the sliding bearing to make installation and maintenance more convenient.

[0022] 5. The design clearance between the trapezoidal lead screw and the sliding bearing is smaller than the backlash of the worm gear. This ensures that when the structure is stationary, the spool valve is subjected to exhaust pressure, and the worm gear eats up part of the backlash. At this time, because the clearance between the trapezoidal lead screw and the sliding bearing is small, the force on the worm gear is fully absorbed by the sliding bearing, which greatly reduces the stress on the worm and enhances the stability of the structure.

[0023] 6. The worm gear assembly uses a lead angle of less than 3.5°, and the number of worm threads is 1, which enables the worm gear to self-lock and ensures the reliability of volume ratio adjustment.

[0024] 7. The transmission method using a lead screw and lead screw nut results in high transmission accuracy and a more stable structure.

[0025] 8. Drill pin holes on the housing, open guide grooves for the Vi slide valve, with the groove width being the same as the pin hole diameter, and install the positioning pin in the pin hole. Using positioning pins instead of the traditional key and keyway mating method greatly reduces the difficulty of housing machining.

[0026] 9. Sliding bearings A and D are specially designed with bearing housings, which greatly reduces assembly difficulty and improves efficiency.

[0027] 10. The slide valve assembly is divided into two sections: the Vi slide valve and the energy-adjustable slide valve, which allows the compressor's energy regulation and volume ratio regulation to be used independently. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This invention relates to a state with the minimum internal volume ratio. Figure 1 BB cross-sectional view; Figure 3 This is the state with the maximum content-to-volume ratio in this utility model. Figure 1 BB cross-sectional view; Figure 4 In this utility model Figure 3 Enlarged view of area A; In the diagram: 1-House 2-Slide valve hole 3-Built-in motor 11-Stepper motor 12-Bracket 13-Planar magnetic coupling 131-Screw 14-Screw 15-Base 16-Sealing ring 21-Bearing seat A 22-Sliding bearing A 23-Worm 24-Sliding bearing B 25-Sliding bearing C 26-Worm wheel 27-Bearing seat B 28-Screw 31-Lead screw 32-Key 33-Vi slide valve 331-Slot 34-Screw 35-Lead screw nut 36-Sealing plug 37-Positioning pin 38-Adjustable slide valve 381-Exhaust port 382-Allowing recess 39-Sliding bearing D. Detailed Implementation

[0029] To make the above-mentioned features and advantages of this utility model more easily understood, specific embodiments are described below in conjunction with the accompanying drawings, but this utility model is not limited thereto.

[0030] refer to Figures 1 to 4 A screw compressor structure with a wide adjustable internal volume ratio includes a worm gear 23 disposed within a housing 1. A stepper motor 11, magnetically coupled to the input end of the worm gear 23, is mounted on the housing 1, thereby transmitting the torque of the stepper motor 11 to the worm gear 23. A lead screw 31, perpendicular to the axis of the worm gear 23, is rotatably connected within the housing 1. A worm wheel 26, meshing with the worm gear 23, is fixed to one section of the lead screw 31. A valve assembly, capable of axial movement within the valve port 2 of the housing, is disposed therein. The other section of the lead screw 31 is threadedly connected to the valve assembly, and the lead screw 31 drives the valve assembly to linear motion by converting rotation into linear motion.

[0031] Through the worm gear 26 and worm 23 transmission structure, the worm and worm change the direction of rotation transmission in an alternating manner, greatly reducing the axial space requirement and overcoming the limitation of the axial space of the built-in motor 3. Due to this compact volume ratio adjustment method, a wide range of volume ratios can be achieved within a limited space, and fully automatic stepless adjustment can be realized, with a range of 2.0 to 4.6. This basically covers the common operating conditions of refrigeration systems.

[0032] In this embodiment, the stepper motor 11 is mounted on the base 15 via a bracket 12. A sealing ring 16, which mates with the housing, is provided in the sealing groove of the base 15. The base 15 is fixedly mounted on the housing 1 by screws 14. The output shaft of the stepper motor 11 is magnetically coupled to the input end of the worm gear 23 via two coupled planar magnetic couplings 13. One of the planar magnetic couplings 13 is located inside the base 15 and fixedly connected to the input end of the worm gear 23. Thus, the torque of the stepper motor 11 is transmitted to the worm gear 23 through the two coupled planar magnetic couplings 13. This structure transforms the original dynamic seal into a static seal, eliminating leakage problems. Furthermore, during torque transmission via the planar magnetic couplings, if the torque exceeds the limit of the planar magnetic coupling, the planar magnetic coupling will slip, greatly protecting the mechanical components and the stepper motor.

[0033] In this embodiment, the planar magnetic coupling 13 is fixed to the output shaft of the stepper motor 11 and the input end of the worm gear 23 by screws 131.

[0034] In this embodiment, a bearing seat A21 with a shoulder is installed inside the housing 1, which is positioned between the housing 1 and the base 15 to restrict the axial movement of the bearing seat A21. A sliding bearing A22 is installed on the bearing seat A21, and a sliding bearing B24 is installed at the bottom of the housing 1. The worm gear 23 is installed between the sliding bearings A22 and B24. Specifically, the profile bottom diameter of the worm gear 23 is larger than the inner diameter of the sliding bearing B24. This design allows the worm gear 23 to be directly screwed in or out during installation and maintenance without being jammed by the worm wheel 26.

[0035] In this embodiment, as Figure 2 As shown, because the semi-hermetic screw compressor has a built-in motor, it cannot directly adjust the volume ratio like an open compressor. Therefore, sliding bearings C25 and D39 are installed above the worm gear 23 inside the housing 1. Sliding bearing C25 is directly installed inside the housing, while sliding bearing D39 is fixed in bearing seat B27 inside the housing. Bearing seat B27 is fixed inside the housing 1 by screws 28. A section of the lead screw 31 is installed on sliding bearings C25 and D39. The worm wheel 26 is located between sliding bearings C25 and D39 and is connected and fixed to the lead screw 31 via a key 32, so that when the worm gear 23 rotates, it drives the worm wheel 26 to rotate, and the worm wheel 26 drives the lead screw 31 to rotate via the key 32.

[0036] In this embodiment, the lead screw is a trapezoidal lead screw, and the fit clearance between the lead screw 31 and the sliding bearings C35 and D39 is 0.05 mm to 0.1 mm. This clearance is smaller than the side clearance (fit clearance) between the worm gear 26 and the worm 23. This ensures that when the structure is stationary, the valve assembly is subjected to exhaust pressure, which is transmitted to the worm gear 26. The worm gear 26 then absorbs part of the side clearance upwards. At this time, because the clearance between the lead screw 31 and the sliding bearings C35 and D39 is small, the force on the worm gear 26 is fully absorbed by the sliding bearings C35 and D39, greatly reducing the stress on the worm 23 and enhancing the stability and service life of the structure.

[0037] In this embodiment, the valve assembly consists of a Vi valve 33 and an adjustable valve 38 connected together. Another section of the lead screw 31 is screwed to a lead screw nut 35 installed inside the Vi valve 33. The lead screw nut 35 is installed inside the Vi valve 33 by screws 34. Because the valve assembly consists of the Vi valve 33 and the adjustable valve 38, the compressor's energy regulation and volume ratio regulation can be used independently.

[0038] In another embodiment, the internal thread of the lead screw can be directly machined on the Vi slide valve 33 so that the Vi slide valve 33 can be directly threaded to the lead screw 31 through the internal thread of the lead screw.

[0039] In this embodiment, a guide groove 331 is axially formed on the side (circumferential surface) of the Vi slide valve 33. A pin hole is drilled on the housing 1, the diameter of which is the same as the diameter of the guide groove 331. A positioning pin 37, one end of which extends into the guide groove, is installed in the pin hole. A sealing plug 36 is sealed on the outside of the positioning pin 37 in the pin hole. The positioning pin 37 serves to both position and prevent the Vi slide valve 33 from rotating, thus converting the rotational motion of the lead screw 31 into the axial movement of the Vi slide valve 33, and to limit the maximum distance the slide valve assembly can move outward along the axial direction of the slide valve hole 2. When the Vi slide valve 33 moves to the bottom of the slide valve hole 2, the exhaust port 381 of the corresponding adjustable slide valve 38 also moves towards the bottom of the slide valve hole 2, at which point the exhaust port 381 is at its maximum, i.e., the volume ratio is at its minimum. When the Vi slide valve 33 moves outward from the slide valve hole 2, the bottom of the guide groove 331 fits against the positioning pin 37, at which point the exhaust port 381 is at its minimum, i.e., the volume ratio is at its maximum. Figure 3 As shown.

[0040] In this embodiment, the adjustable slide valve 38 is provided with a clearance recess 382 on the end near the Vi slide valve 33 to avoid the other end of the lead screw 31, so as to provide clearance space for the movement of the lead screw 31.

[0041] In this embodiment, the entire internal volume ratio structure is installed at the bottom of the housing 1, so that the entire structure can be fully lubricated by the lubricating oil deposited inside the compressor, preventing wear of moving parts.

[0042] In this embodiment, bearing housings A21 and B27 are specially designed for sliding bearing A and sliding bearing D. Through the concentric design of the inner and outer diameters of the bearing housings, the bearing housing A with sliding bearing A and the bearing housing D with sliding bearing D can be installed into the corresponding holes after the worm gear 26 and worm 23 are assembled. This avoids the difficulty of aligning the center holes of the bearings at both ends at the same time, greatly reduces the assembly difficulty and improves efficiency.

[0043] In another embodiment, in addition to the worm gear drive methods listed above, spiral gear drive, staggered helical gear drive, rack and pinion drive, or bevel gear drive can be used to replace the worm gear drive by changing the transmission direction through staggered methods.

[0044] In another embodiment, in addition to the lead screw 31 and lead screw nut 35 transmission methods listed above, the transmission method in which the rotation between the lead screw 31 and Vi slide valve 33 is converted into linear motion includes sliding lead screw nut transmission, ball screw nut transmission, or screw nut transmission.

[0045] Working principle: First, when the slide valve assembly moves to the limit position, the worm gear 26 and worm 23 stop rotating. At this time, even if the stepper motor 11 continues to rotate, the planar magnetic coupling 13 outside the housing 1 continues to rotate, but the planar magnetic coupling 13 inside the housing 1 will slip and stop rotating.

[0046] Based on the above characteristics, the maximum number of rotations is calculated by calculating the two extreme positions of the Vi slide valve 33. Regardless of the position of the Vi slide valve 33, the maximum number of counterclockwise rotations can be defined as the starting position. At this point, the Vi slide valve 33 moves to the bottom of the slide valve orifice 2, where the volume ratio is at its minimum. Figure 2 As shown, the volume ratio is then adjusted based on the relationship between the number of clockwise rotations of the motor and the volume ratio.

[0047] The optimal volume ratio is calculated based on the working conditions. The number of rotations required for the stepper motor 11 is then calculated based on the volume ratio. The stepper motor 11 rotates clockwise from the starting position according to the number of rotations required. The stepper motor drives the planar magnetic coupling 13, causing the worm gear 26 and worm 23 to rotate. The worm gear 26 drives the lead screw 31 to rotate through the key 32, causing the slide valve assembly to move outward from the slide valve hole 2, and the volume ratio gradually increases.

[0048] The worm gear assembly uses a worm 23 with a lead angle of less than 3.5° and a single thread, enabling self-locking of the worm gear 26 and worm 23. This ensures that the worm gear 26 will not rotate even when subjected to external forces, guaranteeing that the valve assembly can stably stop at any position. This ensures the reliability of the volume ratio adjustment.

[0049] When the optimal volume ratio calculated under operating conditions exceeds the maximum volume ratio, the maximum number of rotations is calculated by calculating the two extreme positions of the Vi slide valve 33. The maximum number of rotations of the stepper motor 11 is then programmed to limit the maximum number of rotations. When the stepper motor 11 reaches the maximum number of rotations, the volume ratio reaches its maximum, and the volume ratio is no longer adjusted. This prevents the two planar magnetic couplings 13 from slipping during normal volume ratio adjustment and ensures the accuracy of the adjustment.

[0050] Unless otherwise stated, if any of the technical solutions disclosed in this utility model discloses a numerical range, then the disclosed numerical range is a preferred numerical range. Any person skilled in the art should understand that the preferred numerical range is merely one among many feasible numerical values ​​that has a more obvious or representative technical effect. Because there are many numerical values, it is impossible to list them all. Therefore, this utility model discloses only some numerical values ​​to illustrate the technical solutions of this utility model. Furthermore, the numerical values ​​listed above should not constitute a limitation on the scope of protection of this utility model.

[0051] If this utility model discloses or relates to mutually fixedly connected parts or structural components, then unless otherwise stated, a fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws) or a non-detachable fixed connection (e.g., riveting or welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured by casting) (except where it is obviously impossible to use an integral forming process).

[0052] In addition, unless otherwise stated, the terms used to indicate positional relationships or shapes in any of the technical solutions disclosed in this utility model above include states or shapes that are similar to, close to, or approximate with them.

[0053] Any component provided by this utility model can be assembled from multiple individual components, or it can be a single component manufactured by a one-piece molding process.

[0054] The above description is only a preferred embodiment of the present utility model. All equivalent changes and modifications made within the scope of the patent application of the present utility model shall be covered by the present utility model.

Claims

1. A screw compressor structure with a wide adjustable internal volume ratio, comprising a worm gear disposed within a housing, characterized in that, A stepper motor is installed on the housing and magnetically coupled to the input end of the worm gear. A lead screw is rotatably connected inside the housing and is perpendicular to the axis of the worm gear in space. A worm wheel that meshes with the worm gear is fixed in one section of the lead screw. The worm gear changes the direction of rotational transmission through an interleaved manner. A spool valve assembly that can move axially within the spool valve hole is provided in the spool valve hole of the housing. The other section of the lead screw is threadedly connected to the spool valve assembly, and the lead screw drives the spool valve assembly to move linearly by converting rotation into linear motion.

2. The screw compressor structure with a wide adjustable internal volume ratio according to claim 1, characterized in that, The stepper motor is mounted on a bracket base, and the base is sealed and mounted on the housing.

3. The screw compressor structure with a wide adjustable internal volume ratio according to claim 2, characterized in that, The output shaft of the stepper motor is magnetically coupled to the input end of the worm gear via two coupled planar magnetic couplings, one of which is located inside the base and fixedly connected to the input end of the worm gear.

4. The screw compressor structure with a wide adjustable internal volume ratio according to claim 2, characterized in that, The housing contains a bearing seat A with a shoulder that is engaged between the housing and the base. A sliding bearing A is mounted on the bearing seat A. A sliding bearing B is mounted inside the housing. The worm gear is mounted between the sliding bearing A and the sliding bearing B.

5. The screw compressor structure with a wide adjustable internal volume ratio according to claim 1, characterized in that, Inside the housing, above the worm gear, are sliding bearings C and D. A section of the lead screw is mounted on sliding bearings C and D, and the worm wheel is positioned between sliding bearings C and D.

6. The screw compressor structure with a wide adjustable internal volume ratio according to claim 5, characterized in that, The housing contains a bearing seat B, and the sliding bearing D is installed inside the bearing seat B.

7. A screw compressor structure with a wide adjustable internal volume ratio according to claim 5 or 6, characterized in that, The clearance between the lead screw and the sliding bearings C and D is 0.05 mm to 0.1 mm, which is smaller than the side clearance between the worm gear and the worm.

8. A screw compressor structure with a wide adjustable internal volume ratio according to claim 1, 5, or 6, characterized in that, The valve assembly consists of a Vi valve and an adjustable valve connected together, and another section of the lead screw is screwed to a lead screw nut installed in the Vi valve.

9. The screw compressor structure with a wide adjustable internal volume ratio according to claim 8, characterized in that, The Vi slide valve has a guide groove axially opened on its side, and a pin hole is drilled on the housing. A positioning pin with one end extending into the guide groove is installed in the pin hole, so that the rotational motion of the lead screw is converted into the linear motion of the Vi slide valve along the axial direction.

10. The screw compressor structure with a wide adjustable internal volume ratio according to claim 8, characterized in that, The adjustable slide valve has a clearance recess on the end near the Vi slide valve to avoid the other end of the lead screw.

11. The screw compressor structure with a wide adjustable internal volume ratio according to claim 1, characterized in that, Replace the worm gear drive with a helical gear drive, an interlocking helical gear drive, a rack and pinion drive, or a bevel gear drive.

12. A screw compressor structure with a wide adjustable internal volume ratio according to claim 1 or 9, characterized in that, The slide valve assembly has an internal thread that connects to the lead screw.

13. The screw compressor structure with a wide adjustable internal volume ratio according to claim 1, characterized in that, The transmission method that converts the rotation of the lead screw and the slide valve assembly into linear motion includes sliding lead screw nut transmission, ball screw nut transmission, or screw nut transmission.

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