Shaft seal structure and screw compressor with same

Abstract

The utility model discloses a shaft seal structure and a screw compressor with the shaft seal structure. The shaft seal structure comprises a support fixed on the rotating shaft, a moving ring, a pre-tightening spring arranged between the support and the moving ring, a static ring and a shaft seal cover. The attached end face of the static ring and the movable ring extends outwards to form a circular ring, the outer circle of the movable ring is movably sleeved with the circular ring, and a plurality of comb teeth are arranged on the surface of the inner circle of the circular ring in the axial direction and matched with the outer circle of the movable ring to form a comb tooth sealing mechanism. A cooling groove for oil to flow circularly is further formed in the static ring body. By adding a comb tooth sealing mechanism between the movable ring and the static ring, oil can be prevented from leaking through a wear gap between the faying surfaces of the movable ring and the static ring. Oil can cool the interior of the static ring by adding the oil path of the internal cooling groove of the static ring, so that the cooling efficiency is improved.

Description

Technical Field

[0001] The utility model relates to a mechanical seal device, in particular to a shaft seal structure for axial seal and a screw compressor with the shaft seal structure. Background Art

[0002] With the development of fluid transportation technology, screw compressors have been widely used. Please refer to Figure 1 As shown, a conventional open-type screw compressor includes a machine body 1, an exhaust bearing seat 2 provided at the left end of the machine body, and a suction bearing seat 3 provided at the right end; a pair of spiral male and female rotors 4 are arranged in the machine body through bearings. The male rotor shaft, that is, the input shaft 7 extends to the right through a shaft seal structure 5 arranged in the suction bearing seat 3, and is then connected to the motor shaft through a coupling 6. During operation, the motor drives the male rotor to rotate, and then drives the female rotor to rotate, so that the two mesh and rotate in opposite directions. There are tiny gaps between the male and female rotors 4 and between the machine body 1 and the rotors. When the male and female rotors inhale gas through the suction port at the right end, the male and female rotors rotate to compress the oil-gas mixture, so that the volume of the compression chamber gradually decreases, and the oil-gas mixture is compressed towards the exhaust port at the left end. When the compression chamber passes through the exhaust port, the oil-gas mixture is discharged from the compressor, thus completing an intake-compression-exhaust process, that is, completing a working cycle. Screw compressors have a series of advantages such as a large power range for refrigeration and heating, reliable operation, long service life, convenient operation and maintenance, good dynamic balance, strong adaptability, and can be used for the mixed transportation of multiphase media. Their performance optimization potential is large, and the research and development fields are very extensive.

[0003] As Figure 2 shown, it is a shaft seal structure in an existing open-type screw compressor. The shaft seal structure includes: a bracket 51, a moving ring 52, an existing stationary ring 530, and a shaft seal cover 54. The bracket and the moving ring are fixed on the input shaft 7, and the bracket and the moving ring rotate together with the input shaft. The moving ring and the input shaft are sealed by a first sealing ring 55, but there is no relative movement between the moving ring and the input shaft, so it is a static seal; the existing stationary ring 530 is fixed in the shaft seal cover 54 or fixed on the suction bearing seat, and the existing stationary ring and the shaft seal cover are sealed by a second sealing ring 56, and there is also no relative movement between the existing stationary ring and the shaft seal cover, so it is a static seal. However, the moving ring 52 and the existing stationary ring 530 are axially abutted and fitted. When the moving ring rotates together with the input shaft, the mating surface between the moving ring 52 and the existing stationary ring 530 generates relative movement, that is, the axial mating surface between the moving ring and the existing stationary ring forms a friction pair to achieve dynamic seal. In order to maintain the sealing effect between the axial mating surfaces of the moving ring and the existing stationary ring, a pre-tightening spring 57 is provided between the axial directions of the bracket and the moving ring to press the mating surface between the moving ring and the stationary ring.

[0004] When the unit is running, driven by the input shaft 7, the friction pair formed by the dynamic ring and the existing static ring moves relative to each other, which will generate a lot of heat. Therefore, oil needs to be introduced in time for cooling and lubrication. Figure 2 As shown, an oil supply inlet 33 and an oil return port 32 are provided on the main body of the suction bearing seat 3 to form a circulating oil supply circuit for cooling the shaft seal structure. The pressure in the above-mentioned shaft seal structure is the oil pressure Po, and the pressure at the connection between the right end of the input shaft and the coupling 6 is the atmospheric pressure Pa. Since the oil in the shaft seal structure usually returns to the suction side of the compressor, and the suction pressure is Ps, at this time, the magnitude of Po and Ps is basically the same, but both are greater than the atmospheric pressure Pa. In order to prevent oil from leaking onto the input shaft, a barrier to prevent oil leakage is usually provided, such as a first sealing ring 55 between the dynamic ring and the input shaft, a second sealing ring 56 between the existing static ring and the shaft seal cover, and an axial fitting surface between the dynamic ring and the existing static ring. As the input shaft 7 rotates, the axial fitting surface between the dynamic ring 52 and the existing static ring 530 will wear. Although a preload spring 57 is provided on the left side of the dynamic ring to compensate for the wear between the dynamic and static rings, the tightness of the fitting surface between the dynamic ring and the existing static ring will still decrease with wear. Therefore, the oil will flow into the gap between the input shaft and the dynamic ring and the existing static ring through the gap between the fitting surfaces of the two, and be discharged out of the machine through the pipeline of the leakage oil outlet 541. Since the oil leaks directly to the outside from the cover between the compressor housing and the motor, it will reduce the cooling and lubrication effects of the shaft seal structure and affect the safety and cleanliness of the unit. Furthermore, it cannot meet the national standard requirements for the oil leakage of the shaft seal, that is, the oil leakage must be less than 3 mg / h. Therefore, in order to reduce the amount of oil leakage, it is necessary to optimize the sealing of the shaft seal structure.

[0005] In addition, the moving ring is made of non-metallic materials with lower hardness, such as graphite materials, and the stationary ring is made of materials with higher hardness, such as silicon carbide materials. The moving ring is made of a softer material that is easy to wear, while the stationary ring is made of a harder material, and the performance of the two is compatible. The existing stationary ring material has good thermal conductivity and generates a large amount of heat, and usually requires enhanced cooling. However, the existing conventional oil circuit can only cool the outer surface of the moving ring and the existing stationary ring, and cannot directly cool the inside of the moving ring and the existing stationary ring, resulting in poor cooling cycle effect. Due to the low cooling efficiency of the moving and stationary rings, the high temperature generated by the friction between the two will aggravate the friction loss between the moving and stationary rings, including friction energy loss and wear loss of the moving ring, and will also reduce the overall energy efficiency of the compressor and the life of the shaft seal. Secondly, high temperature will cause the oil temperature to be too high, reduce the service life of the oil, and even cause oil carbonization.

[0006] In view of the above problems, in this field, a set of external cooling devices is adopted to introduce high-pressure media to ensure the cooling effect and sealing effect of the mechanical seal of the shaft seal structure. Although it can improve the cooling and sealing effects and enhance the operation reliability, it requires additional devices to be set up, increasing the cost and floor space, which is not an ideal choice. There is also a multi-stage non-contact seal designed based on the balance pipe principle, which can prevent the leakage of the balanced medium to achieve sealing. However, the disadvantage is that it requires continuous injection of sealing inert gas and cannot be used in closed systems such as refrigeration systems.

[0007] Therefore, in this technical field, it is necessary to solve the problem that after the unit operates for a period of time, due to the wear between the moving ring and the existing stationary ring, the oil leakage amount from the shaft seal gradually increases. In addition, it is also necessary to solve the problem of low cooling cycle efficiency of the stationary ring of the shaft seal structure. Summary of the Utility Model

[0008] The utility model aims to solve the problem that after the existing screw compressor unit operates for a period of time, due to the wear between the moving ring and the existing stationary ring, the oil leakage amount from the shaft seal gradually increases. In addition, it is also necessary to solve the problem of low cooling cycle efficiency of the stationary ring of the shaft seal structure.

[0009] A shaft seal structure provided by the utility model includes a bracket fixed on a rotating shaft, a moving ring, a preloading spring arranged between the bracket and the moving ring, a stationary ring, and a shaft seal cover. A circular ring extends outward from the mating end face of the stationary ring and the moving ring, and this circular ring is sleeved on the outer circle of the moving ring. A plurality of comb teeth are arranged axially on the inner circle surface of the circular ring and cooperate with the outer circle of the moving ring to form a comb tooth seal mechanism.

[0010] Preferably, a step is provided on the inner circle at one end of the bracket relative to the moving ring, and the preloading spring is arranged between the step of the bracket and the moving ring.

[0011] Preferably, spring mounting holes are annularly and evenly arranged on the step surface of the bracket. The preloading spring is a slender small spring, one end of which is inserted into the spring mounting hole, and the other end abuts against the moving ring.

[0012] Preferably, a washer is arranged between the preloading spring and the moving ring.

[0013] Preferably, there are 6 - 10 comb teeth in the comb tooth seal mechanism.

[0014] Preferably, cooling grooves are formed on the body of the stationary ring, and a plurality of oil holes communicating with the cooling grooves are arranged on the outer circle of the stationary ring. A third sealing ring is arranged on the end face of the stationary ring opposite to the shaft seal cover to prevent the oil in the cooling grooves from flowing to the surface of the rotating shaft.

[0015] Preferably, the outer circle of the shaft seal cover is evenly distributed with oil supply holes facing the oil holes on the stationary ring, and the main body of the suction bearing seat is provided with oil outlet holes at the same height as the outer circle of the stationary ring.

[0016] Preferably, the cooling groove is an annular cooling groove.

[0017] Preferably, the stationary ring has 8-10 oil holes evenly distributed along its circumference.

[0018] The utility model also provides a screw compressor with the shaft sealing structure.

[0019] The utility model improves the structure of the stationary ring, so that the mating end surfaces of the stationary ring and the dynamic ring extend a circular ring outward, and the inner circle of the circular ring is just loosely fitted on the outer circle of the dynamic ring, that is, the dynamic ring can rotate relative to the circular ring of the stationary ring. A plurality of comb teeth are axially arranged on the inner circle surface of the circular ring and cooperate with the outer circle of the dynamic ring to form a comb tooth sealing mechanism. An axial comb tooth sealing mechanism is added between the dynamic and static rings, which can prevent the oil in the outer periphery of the dynamic and static rings from entering the mating surface of the dynamic and static rings as much as possible, and effectively solves the problem of the gradual increase in the amount of oil leakage from the shaft seal due to the friction and wear between the dynamic ring and the static ring.

[0020] A cooling groove for cooling oil circulation is set in the body of the static ring, which greatly increases the cooling area of ​​the static ring, improves the cooling effect of the static ring, and effectively prevents the friction loss between the dynamic and static rings due to excessive static ring temperature. At the same time, it prolongs the service life of the oil, saves energy loss due to friction and wear, and improves the overall energy efficiency of the compressor and the life of the shaft seal. This solves the problem of low cooling cycle efficiency of the static ring of the shaft seal structure.

[0021] In addition, the utility model provides an oil supply channel on the outer circle of the shaft seal cover and faces the oil hole on the stationary ring, while an oil outlet hole is provided on the main body of the air intake bearing seat at the same height as the outer circle of the stationary ring. In this way, part of the oil ejected from the oil supply channel can enter the cooling groove of the stationary ring through the oil hole on the outer circle of the stationary ring to flow, cool and exchange heat, and the other part of the oil can be deposited in the space outside the dynamic and static rings. When the oil level of the deposited oil is higher than the oil outlet hole, it will flow back into the unit, and the dynamic and static rings are immersed in the oil bath. Therefore, the heat exchange area is greatly increased, and the efficiency of the dynamic and static ring cooling cycle is further improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of the structure of a screw compressor provided by the utility model;

[0023] Figure 2 It is a schematic diagram of the shaft seal structure of an existing screw compressor;

[0024] Figure 3 for Figure 1 Schematic diagram of shaft seal structure;

[0025] Figure 4 is Figure 3 A three-dimensional schematic diagram of the middle support;

[0026] Figure 5 is Figure 3 A three-dimensional schematic diagram of the middle moving ring;

[0027] Figure 6 is Figure 3 A three-dimensional schematic diagram of the left view of the middle stationary ring;

[0028] Figure 7 is Figure 3 A three-dimensional schematic diagram of the right view of the middle stationary ring;

[0029] Figure 8 is Figure 3 A three-dimensional schematic diagram of the middle shaft seal cover.

[0030] In the figure:

[0031] 1 - body; 2 - exhaust bearing housing; 3 - suction bearing housing; 31 - oil passage outlet hole; 32 - oil return port;

[0032] 33 - oil supply inlet; 4 - male and female rotors; 5 - shaft seal structure; 6 - coupling; 7 - input shaft;

[0033] Markings in the shaft seal structure 5:

[0034] 51 - support; 511 - step; 512 - spring mounting hole; 52 - moving ring; 53 - stationary ring; 530 - existing stationary ring;

[0035] 531 - circular ring; 532 - comb teeth; 533 - cooling groove; 534 - oil hole;

[0036] 54 - shaft seal cover; 541 - leakage oil outlet; 542 - oil supply passage;

[0037] 55 - first sealing ring; 56 - second sealing ring; 57 - preloading spring; 58 - third sealing ring; 59 - gasket. Specific embodiments

[0038] In order to make the objectives, technical solutions and advantages of the present utility model clearer, the following provides a detailed description of the present utility model in conjunction with the accompanying drawings and embodiments. It should be understood that the following specific embodiments are only used to explain the present utility model and do not constitute a limitation to the present utility model.

[0039] As Figure 1As shown in the figure, the present utility model provides an open-type screw compressor, which includes a machine body 1, an exhaust bearing seat 2 provided at the left end of the machine body, and a suction bearing seat 3 provided at the right end; a pair of spiral male and female rotors 4 are arranged in the machine body through bearings at both ends. The male rotor shaft, that is, the input shaft 7, extends rightward through the improved shaft seal structure 5 of the present utility model provided in the suction bearing seat 3, and is then connected to the motor shaft through a coupling 6. During operation, the motor (not shown in the figure) drives the male rotor to rotate, and then drives the female rotor to rotate, that is, the two mesh and rotate in opposite directions. There are small gaps between the male and female rotors 4 and between the machine body 1 and the pair of rotors. When the male and female rotors inhale gas through the suction port at the right end, the male and female rotors rotate to compress the oil-gas mixture, so that the volume of the compression chamber gradually decreases, and the oil-gas mixture is compressed toward the exhaust port at the left end. When the compression chamber passes through the exhaust port, the oil-gas mixture is discharged from the compressor, thus completing an intake-compression-exhaust process, that is, completing a working cycle.

[0040] Please refer to Figure 3 , the first embodiment of the newly improved shaft seal structure 5 provided by the present utility model. The shaft seal structure 5 includes a bracket 51 and a moving ring 52 fixed on the input shaft 7. The left end of the bracket abuts against the shoulder of the input shaft, and a preloading spring 57 is provided between the right end of the bracket and the left end of the moving ring. As Figure 4 , Figure 5 shown, in order to ensure the stable and reliable operation of the preloading spring, a step 511 is provided in the inner circle of the right end of the bracket relative to the moving ring, and spring installation holes 512 are evenly arranged in a ring on the step surface. The preloading spring is a slender small spring, and its left end is inserted into the spring installation hole, that is, a preloading spring 57 surrounding the input shaft 7 in a circle is axially arranged in the inner circle of the bracket. Setting the preloading spring in this way is convenient for adjustment, and the preloading force can also meet the requirements. According to needs, a complete preloading spring can also be used, and the preloading spring is sleeved on the input shaft 7 and arranged between the step 511 of the inner circle of the bracket and the moving ring 52 axially. Oil guiding holes are evenly distributed on the circumferential surface of the bracket for supplying oil to enter the inside of the bracket for cooling. And the left end of the moving ring extends into the inner circle of the right end of the bracket. Since the material of the moving ring is relatively soft, a ring-shaped washer 59 with a certain hardness is provided between the preloading spring and the moving ring. The preloading spring presses against the washer and then presses the moving ring, so that the preloading spring can apply sufficient preloading force and can also prevent damage to the moving ring. The right end of the moving ring 52 is in contact with the left end face of the stationary ring 53 to form a friction pair. The right end of the stationary ring 53 is abutted and fixed to the inner wall of the suction bearing seat 3 by the shaft seal cover 54, that is, the shaft seal parts are fixed through the shaft seal cover to achieve the shaft seal function. The moving ring can be made of a non-metallic material with a lower hardness, such as graphite material, and the stationary ring can be made of a material with a higher hardness, such as silicon carbide material. The moving ring is made of a softer and easily worn material, while the stationary ring material is harder, and the hardness of the two is adapted. The heat generated by the stationary ring material is relatively large and the thermal conductivity is good, and the temperature can be reduced by strengthening cooling.

[0041] As Figure 6 shown, the stationary ring 53 of this embodiment has been structurally improved. That is, a circular ring 531 extends leftward from the mating end face of the stationary ring and the rotating ring. The circular ring is sleeved on the outer circle of the right end of the rotating ring 52, that is, the rotating ring 52 can rotate relative to the circular ring 531 of the stationary ring. A plurality of annular comb teeth 532 are arranged axially on the inner circle surface of the circular ring and cooperate with the outer circle of the rotating ring to form a comb tooth sealing mechanism. Generally, there are 6 - 10 comb teeth in this comb tooth sealing mechanism, which can ensure the effect of comb tooth sealing. In addition, a first sealing ring 55 is provided between the rotating ring and the input shaft, and a second sealing ring 56 is provided between the stationary ring and the shaft seal cover. From Figure 3 it can be seen that as the input shaft rotates continuously, after the mating surface of the rotating and stationary rings wears severely and the gap becomes larger, at this time, since there is a sealing mechanism with 6 or more comb teeth between the rotating and stationary rings, through this comb tooth sealing mechanism, it is possible to prevent the oil in the outer environment of the rotating and stationary rings from entering the gap of the mating surface of the rotating and stationary rings and leaking out as much as possible. It effectively solves the problem that the amount of oil leaked due to the friction and wear between the rotating ring and the stationary ring gradually increases.

[0042] As Figure 3 shown, in the preferred embodiment of the shaft seal structure 5 provided by the present utility model, its overall structure is substantially the same as that of the first embodiment. That is, the shaft seal structure 5 includes a bracket 51 and a rotating ring 52 fixed on the input shaft 7. The left end of the bracket abuts against the shoulder of the input shaft, and a preloading spring 57 is provided between the right end of the bracket and the left end of the rotating ring. As Figure 4 、 Figure 5 shown, in order to ensure the stable and reliable operation of the preloading spring, a step 511 is provided in the inner circle of the right end of the bracket relative to the rotating ring, and spring mounting holes 512 are evenly arranged annularly on the step surface. The preloading spring is a slender small spring, and its left end is inserted into the spring mounting hole, that is, a preloading spring 57 that surrounds the input shaft 7 in a circle is axially provided in the inner circle of the bracket. Such a setting of the preloading spring is convenient for adjustment and the preloading force also meets the requirements. According to needs, a complete preloading spring can also be used. The preloading spring is sleeved on the input shaft 7 and is arranged between the step 511 of the inner circle of the bracket and the axis of the rotating ring 52. Oil guiding holes are also evenly distributed on the circumferential surface of the bracket for supplying oil into the interior of the bracket for cooling. And the left end of the rotating ring extends into the inner circle of the right end of the bracket. Since the material of the rotating ring is relatively soft, a ring-shaped washer 59 with a certain hardness is provided between the preloading spring and the rotating ring to ensure that the preloading spring exerts sufficient preloading force and prevent damage to the rotating ring. The right end of the rotating ring 52 is in contact with the left end face of the stationary ring 53 to form a friction pair, and the right end of the stationary ring 53 is abutted and fixed to the inner wall of the suction bearing seat 3 by the shaft seal cover 54, that is, the shaft seal parts are fixed through the shaft seal cover to achieve the shaft seal function.

[0043] As Figure 6As shown, the stationary ring 53 of the preferred embodiment has been comprehensively improved. That is, a circular ring 531 extends to the left from the mating end surfaces of the stationary ring and the dynamic ring, and the circular ring is movably fitted on the outer circle of the right end of the dynamic ring 52, that is, the dynamic ring 52 can rotate relative to the circular ring 531 of the stationary ring. A plurality of annular comb teeth 532 are axially provided on the inner circle surface of the circular ring, and cooperate with the outer circle of the dynamic ring to form a comb tooth sealing mechanism. The comb tooth sealing mechanism generally has 6-10 comb teeth, which can ensure sufficient oil circulation flow inside the stationary ring and better cooling effect. In addition, a first sealing ring 55 is provided between the dynamic ring and the input shaft, and a second sealing ring 56 is provided between the stationary ring and the shaft seal cover. By Figure 3 It can be seen that as the input shaft rotates continuously, the gap between the dynamic and static rings becomes larger after the joint surfaces are seriously worn. At this time, since there is a sealing mechanism with 6 or more comb teeth between the dynamic and static rings, the comb teeth sealing mechanism can prevent the oil in the surrounding environment of the dynamic and static rings from entering the gap between the joint surfaces of the dynamic and static rings and leaking out as much as possible. This effectively solves the problem of the gradual increase in the amount of oil leakage from the shaft seal due to the friction and wear between the dynamic and static rings.

[0044] like Figure 7 As shown, in addition to the above-mentioned use of the comb-tooth sealing mechanism to improve the sealing performance of the stationary ring 53, a cooling groove 533 is also opened in the body of the stationary ring, and the outer circle of the stationary ring is provided with a plurality of oil holes 534 connected to the cooling groove. Generally, there are 8-10 oil holes evenly distributed along the circumference of the stationary ring, which is convenient for the oil to enter quickly and evenly. In this preferred embodiment, the cooling groove is arranged as an annular cooling groove 533, and the end face relative to the inner wall of the intake bearing seat 3 is open, so that machining and oil circulation flow accelerate cooling and heat exchange. A third sealing ring 58 is also provided on the end face of the stationary ring opposite to the shaft seal cover. The outer diameter of the sealing ring is smaller than the inner diameter of the annular cooling groove 533, so as to prevent the oil in the cooling groove from flowing downward along the joint surface between the stationary ring and the inner wall of the intake bearing seat 3 to the surface of the input shaft 7. The sealing rings in the present utility model can all be O-rings. Please refer to Figure 3, oil supply holes 542 are evenly distributed on the outer circle of the shaft seal cover 54 and are aligned with the oil holes 534 on the stationary ring. When the unit sprays and supplies oil through the oil supply holes 542, it is very easy to pump the oil into the cooling groove 533 of the stationary ring. Moreover, an oil passage outlet hole 31 is provided on the body of the suction bearing housing 3 at the same height as the outer circle of the stationary ring 53. A circulating cooling oil passage for the shaft seal structure 5 is formed through the oil supply holes 542 and the oil passage outlet hole 31. A part of the oil entering through the oil supply holes 542 enters the cavity of the cooling groove 533 of the stationary ring through the oil holes 534 on the circumference of the stationary ring, and the remaining oil flows into the cavity between the shaft seal cover and the stationary and rotating rings. Since the position of the oil passage outlet hole 31 is set above, the oil flowing into the cavity will deposit and cause the oil level to gradually rise. At the same time, the oil will also enter the cooling groove through the oil hole 534 on the lower side of the stationary ring. When the oil level is high enough and reaches the height of the oil passage outlet hole 31, the oil will flow back into the unit through the oil passage outlet hole 31. At this time, the stationary and rotating rings are in the state of being immersed in the oil bath. Since both the inner and outer wall surfaces of the stationary ring are in contact with the oil, the contact area is significantly increased and the oil flow area is larger, the oil circulation flow rate is more sufficient, and the overall cooling effect of the shaft seal is better. That is, the cooling cycle efficiency of the stationary and rotating rings is further improved. It effectively prevents the friction loss between the stationary and rotating rings from being aggravated due to the too high temperature of the stationary ring. It prolongs the service life of the oil, saves the energy loss of friction and wear, and improves the overall energy efficiency of the compressor and the shaft seal life. Thus, the problem of low cooling cycle efficiency of the stationary and rotating rings of the shaft seal structure is solved.

[0045] The innovative technical idea of the shaft seal structure provided by the present utility model is that the stationary ring and the rotating ring are not only in a single-sided fitting relationship. A part of the stationary ring extends out to cover a part of the rotating ring, and a comb tooth sealing mechanism is arranged on the inner circle of the covered part to prevent oil from entering the fitting surface of the stationary and rotating rings. At the same time, a plurality of oil passages are arranged on the stationary ring to communicate with the hollow cooling groove inside the stationary ring to cool the stationary ring. Since there is oil stored inside the stationary ring, an O-ring is added on the fitting surface between the stationary ring and the shaft seal cover to prevent the oil from flowing to the input shaft through the joint surface between the stationary ring and the shaft seal cover. By adding the comb tooth sealing mechanism between the stationary and rotating rings, it can prevent the oil from leaking through the wear gap between the fitting surfaces of the stationary and rotating rings. By increasing the oil passage of the internal cooling groove of the stationary ring, the oil can cool the inside of the stationary ring to improve the cooling efficiency.

[0046] It should be noted that the terms used in this specification are only for describing the specific embodiments and are not intended to limit the present utility model. Unless otherwise specifically stated, the relative arrangements of the technical features and steps, digital expressions and numerical values described in these embodiments do not limit the protection scope of the present utility model.

[0047] For the technologies, methods and equipment known to those of ordinary skill in the relevant fields, no detailed discussion is made in this specification, but in appropriate cases, the said technologies, methods and equipment should be regarded as a part of this specification. Any specific value in this specification should be interpreted as merely exemplary and not as a limitation to the present utility model.

[0048] For the sake of convenience in description, the terms for describing positions used in the specification, such as "above...", "to the left of...", "in front of...", etc., are only used to describe the spatial position relationship between a certain component of the embodiment shown in the drawings and other components. When the position where the component is placed is different, the relative position will change. Therefore, the positional relationship of the embodiments in the drawings should not constitute a limitation to the present utility model.

[0049] In addition, it should be noted that the use of words such as "first", "second", etc. in the specification is only for distinguishing similar components, and there is no sequence in terms of priority. Therefore, it should not be construed as a limitation to the protection scope of the present utility model.

[0050] The above is only the specific implementation manner of the present utility model. It should be pointed out that any modifications, equivalent replacements, and changes made within the spirit and framework of the concept of the present utility model should be included in the protection scope of the present utility model.

Claims

1. A shaft seal structure, comprising a bracket fixed on a rotating shaft, a moving ring, a preloading spring arranged between the bracket and the moving ring, a stationary ring and a shaft seal cover, characterized in that, The mating end face of the stationary ring and the rotating ring extends outward to form a circular ring, which is sleeved on the outer circle of the rotating ring. The inner circle surface of the circular ring is axially provided with a plurality of comb teeth, which cooperate with the outer circle of the rotating ring to form a comb tooth sealing mechanism.

2. The shaft seal structure according to claim 1, characterized in that, A step is provided in the inner circle of one end of the bracket relative to the rotating ring, and the preloading spring is arranged between the step surface of the bracket and the rotating ring.

3. The shaft seal structure according to claim 2, characterized in that, Spring mounting holes are evenly arranged in a ring on the step surface of the bracket. The preloading spring is a slender small spring. One end of the preloading spring is inserted into the spring mounting hole, and the other end abuts against the rotating ring.

4. The shaft seal structure according to claim 1, wherein, A washer is further arranged between the preloading spring and the rotating ring.

5. The shaft seal structure according to claim 1, wherein, The number of comb teeth in the comb tooth sealing mechanism is 6-10.

6. The shaft seal structure according to any one of claims 1 to 5, characterized in that, Cooling grooves are formed in the body of the stationary ring, and a plurality of oil holes communicating with the cooling grooves are provided on the outer circle of the stationary ring. A third sealing ring is provided on the end face of the stationary ring opposite to the shaft seal cover to prevent the oil in the cooling grooves from flowing to the surface of the rotating shaft.

7. The shaft seal structure according to claim 6, characterized in that, Oil supply channels are evenly distributed on the outer circle of the shaft seal cover and face the oil holes on the stationary ring. Oil outlet holes are provided on the body of the suction bearing seat at the same height as the outer circle of the stationary ring.

8. The shaft seal structure according to claim 6, characterized in that, 8-10 oil holes are evenly distributed along the circumference of the stationary ring.

9. The shaft seal structure according to claim 6, wherein, The cooling grooves are annular cooling grooves.

10. A screw compressor, characterized in that, It includes the shaft seal structure according to any one of claims 1 to 9.

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