JP2015190405A - compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compressor capable of reducing a load acting on a radial bearing remarkably while a structure of the radial bearing is being simplified.SOLUTION: There are provided rotor main bodies (21, 31); a casing (50); the first shafts (22, 32); the second shafts (26, 36); the first radial bearings (41, 43); the second radial bearings (42, 44) and a load reducing mechanism for reducing a radial load acted on the first radial bearings (41, 43). The load reducing mechanism acts a load reducing force including a component facing opposite to a component in a radial direction of a force acted on the rotor main bodies (21, 31) at a more forward part than the first radial bearings (41, 43) against the first shafts (22, 32), or acts a load reducing force including a component facing the same direction as that of the component of a radial direction acted on the rotor main bodies (21, 31) at a more rearward location than that of the second bearings (42, 44) against the second shafts (26, 36).

Description

  The present invention relates to a compressor.

  Conventionally, a compressor capable of reducing a radial load acting on a radial bearing that receives a rotor shaft of a screw rotor is known. For example, Patent Document 1 discloses a compressor including a screw rotor having a rotor shaft and a radial bearing that receives the rotor shaft. The radial bearing is formed with an oil supply path for supplying high-pressure oil to the space between the radial bearing and the rotor shaft. The position of the oil supply path is set so that the direction of the load acting on the rotor shaft due to the pressure of the oil supplied through the oil supply path is opposite to the direction of the radial load acting on the radial bearing from the rotor shaft. Yes. Therefore, by supplying high-pressure oil to the space between the radial bearing and the rotor shaft through the oil supply path, the radial load acting on the radial bearing is reduced.

JP 2008-157330 A

  By the way, in a screw compressor, a bigger load than what is located in a suction side acts on a radial bearing located in the discharge side of a screw compressor among radial bearings arranged on both sides of a screw rotor. In order to secure the bearing width, the radial bearing located on the discharge side must be enlarged.

  In addition, when it is going to employ | adopt the method of reducing the radial load disclosed by patent document 1, since the oil supply path is formed in the radial bearing, the structure of a radial bearing will become complicated. Further, the radial bearing is required to have a strength capable of withstanding the pressure of oil supplied to the space between the radial bearing and the rotor shaft.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a compressor capable of greatly reducing the load acting on the radial bearing while simplifying the structure of the radial bearing.

  As means for solving the above-mentioned problems, the present invention includes a rotor body that is a screw part, a casing that covers the rotor body, and a front part in the longitudinal direction of the rotor body, and is compressed by the rotor body. A discharge port for discharging the gas, a suction port for sucking the gas located at a rear portion in the longitudinal direction of the rotor body, a first shaft extending forward from the rotor body, and backward from the rotor body A second shaft extending in the radial direction, a first radial bearing that supports the first shaft in the radial direction, a second radial bearing that supports the second shaft in the radial direction, and a radial load acting on the first radial bearing. A load reducing mechanism for reducing the load, and the load reducing mechanism is opposite to a radial component of a force acting on the rotor body on the front side of the first radial bearing. A load reduction force including a component of the same direction as the component of the radial direction of the force acting on the rotor body behind the second bearing, or a load reducing force including a crack component on the first shaft. A compressor for applying a force to the second shaft is provided.

  In a compressor provided with a screw rotor, the fluid pressure increases as it is closer to the discharge side. Therefore, it is more desirable to reduce the radial load acting on the first radial bearing located on the discharge side. In this compressor, by providing the load reducing mechanism, it is possible to easily reduce the load of the first radial bearing without performing special processing on the first radial bearing.

  In this case, the load reducing mechanism includes a high-pressure chamber capable of accommodating a high-pressure fluid around the first shaft, and a low-pressure chamber having a lower pressure than the high-pressure chamber, and the high-pressure chamber and the low-pressure chamber It is preferable to generate the load reducing force including a component in the direction opposite to the radial component of the force acting on the rotor body in front of the first radial bearing.

  In this way, a load reducing force can be easily generated.

  Specifically, it is preferable that an outer diameter of a portion of the first shaft that contacts the high pressure chamber is larger than an outer diameter of another portion of the first shaft in the longitudinal direction.

  If it does in this way, a pressure receiving area can be enlarged and a load reduction force can be ensured easily.

  Further, in the present invention, the casing forms the high-pressure chamber and the low-pressure chamber, and the opening that houses the rotor body and the first radial bearing and has an opening opening forward. It is preferable that the sub casing is detachably attached to the rotor casing.

  Since the sub casing is detachable from the rotor casing, a load reducing mechanism can be added to the existing compressor while using the rotor casing of the existing compressor as it is.

  In this case, it is preferable that the sub-casing has a high-pressure introduction channel that introduces oil contained in the fluid discharged from the compressor as the high-pressure fluid into the high-pressure chamber.

  In this way, the oil discharged from the compressor is supplied as a high-pressure fluid to the high-pressure chamber, so that a dedicated supply source for supplying the high-pressure fluid to the high-pressure chamber can be omitted.

  Further, in the present invention, another rotor body which is a screw portion meshing with the rotor body, another first shaft extending forward from the other rotor body, and other extending backward from the other rotor body. A second shaft, another first radial bearing that supports the other first shaft in the radial direction, another second radial bearing that supports the other second shaft in the radial direction, and the other first A load reducing mechanism for reducing a radial load acting on the radial bearing, wherein the load reducing mechanism is capable of accommodating a high pressure fluid around the other first shaft, and the other The other rotor is provided in front of the other first radial bearing due to a pressure difference between the other high pressure chamber and the other low pressure chamber. Opposite to the radial component of the force acting on the body It is preferable to generate the load reduction force containing the component.

  In this way, a load reducing force can be easily generated.

  As described above, according to the present invention, it is possible to provide a compressor capable of reducing the load acting on the radial bearing with a smaller load while simplifying the structure of the radial bearing.

It is a figure which shows the outline of a structure of the compressor of one Embodiment of this invention. It is sectional drawing in the II-II line | wire shown in FIG. It is the schematic of the compression apparatus containing the compressor shown in FIG. It is the schematic which shows the principle of a load reduction mechanism. It is the schematic which shows the principle of the modification of a load reduction mechanism.

  A compressor 1 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4.

  As shown in FIG. 1, the compressor 1 of this embodiment includes a pair of screw rotors 10, four radial bearings 41 to 44 that receive the pair of screw rotors 10, a pair of screw rotors 10, and each radial bearing 41. And a casing 50 that accommodates .about.44. A suction port 50a is provided on the upper side of the pair of screw rotors 10 in the vertical direction and in the rear part (right direction in FIG. 1) of the pair of screw rotors 10 in the longitudinal direction. A discharge port 50b is provided below the suction port 50a in the vertical direction and at the front (left direction in FIG. 1) portion in the longitudinal direction. Note that the vertical direction is not necessarily the vertical direction in the direction of gravity.

  The pair of screw rotors 10 includes a male rotor 20 and a female rotor 30.

  The male rotor 20 includes a rotor body 21 that is a screw part, a first shaft 22 that extends forward from the rotor body 21, and a second shaft 26 that extends rearward from the rotor body 21.

  The 2nd axis | shaft 26 has the connection part 27 connected to the drive machine 2 (refer FIG. 3). The second shaft 26 is rotationally driven by the drive machine 2.

  Similar to the male rotor 20, the female rotor 30 includes a rotor body 31 that is a screw part, a first shaft 32 that extends forward from the rotor body 31, and a second shaft 36 that extends rearward from the rotor body 31. ing. However, the second shaft 36 does not have a portion connected to the driving machine 2.

  The four radial bearings 41 to 44 include a first radial bearing 41 that supports the first shaft 22 of the male rotor 20 in the radial direction, and a second radial bearing 42 that supports the second shaft 26 of the male rotor 20 in the radial direction. The first radial bearing 43 that supports the first shaft 32 of the female rotor 30 in the radial direction and the second radial bearing 44 that supports the second shaft 36 of the female rotor 30 in the radial direction are provided.

  The casing 50 includes a rotor casing 52 that houses the rotor bodies 21 and 31 and the radial bearings 41 to 44, and a sub casing 54 that is detachably attached to the rotor casing 52.

  The rotor casing 52 has an opening 53 that opens forward. An end 22b on the front side of the first shaft 22 of the male rotor 20 (hereinafter referred to as “outer portion 22b”) and an end 32b on the front side of the first shaft 32 of the female rotor 30 (hereinafter referred to as “outer portion 32b”). Is projected forward from the opening 53.

  The first shaft 22 of the male rotor 20 has a base shaft 23 that extends forward from the rotor body 21 and a large-diameter portion 24 b that is attached around the front end portion 23 b of the base shaft 23. The portion 23b and the large diameter portion 24b constitute the outer portion 22b. Similarly, the first shaft 32 of the female rotor 30 includes a base shaft 33 that extends forward from the rotor body 31 and a large-diameter portion 34 b that is attached around the front end portion 33 b of the base shaft 33. The end portion 33b and the large diameter portion 34b constitute the outer portion 32b. The outer diameter of each large diameter part 24b, 34b is formed larger than the outer diameter of each base shaft 23, 33.

  The sub casing 54 has a shape that closes the opening of the opening 53 and accommodates the outer portions 22b and 32b. The sub casing 54 includes a partition portion 55 that divides a space formed around the outer portion 22b in the circumferential direction at a position where the outer portion 22b of the male rotor 20 is sandwiched from both sides in the vertical direction, and an outer portion 32b of the female rotor 30. And a partition portion 56 that partitions a space formed around the outer side portion 32b in the circumferential direction at a position where it is sandwiched from both sides in the vertical direction.

  As shown in FIG. 2, the outer casings 22 b and 32 b in the sub casing 54 are arranged outside the partition part 55 (left side in FIG. 2) and outside the partition part 56 (right side in FIG. 2). High pressure chambers 54a capable of accommodating a high pressure fluid are formed at two locations. A low pressure chamber 54b having a pressure lower than that of the high pressure chamber 54a is formed at one position inside the partition portion 55 and inside the partition portion 56 in the sub-casing 54 in the arrangement direction. The high pressure chamber 54a on the male rotor 20 side is in contact with the outer peripheral surface 22c on the outer side of the outer portion 22b in the arrangement direction. The high-pressure chamber 54a on the female rotor 30 side is in contact with the outer peripheral surface 32c on the outer side of the outer portion 32b in the arrangement direction. The low pressure chamber 54b is in contact with both the outer peripheral surface 22d inside the outer portion 22b and the outer peripheral surface 32d inside the outer portion 32b in the arrangement direction. Clearances (not shown) are formed between the outer portion 22b of the male rotor 20 and the partition portion 55 and between the outer portion 32b of the female rotor 30 and the partition portion 56, respectively.

  The sub casing 54 has a high-pressure introduction channel 58 that communicates with the high-pressure chamber 54a, and a low-pressure communication channel 59 (see FIG. 2) that communicates with the low-pressure chamber 54b.

  As FIG. 3 shows, the compressor 1 of this embodiment comprises a compression apparatus with the gas-liquid separator 3 and the oil supply flow path 4. As shown in FIG.

  The gas-liquid separator 3 separates the fluid discharged from the discharge port 50b into gas and oil. The gas separated by the gas-liquid separator 3 is sent to the downstream side, and the oil separated by the gas-liquid separator 3 is returned into the compressor 1 through the oil supply passage 4.

  The oil supply passage 4 is connected to the sub casing 54 so that high-pressure oil can be introduced into the high-pressure chamber 54 a through the high-pressure introduction passage 58. The oil supply flow path 4 is provided with a cooler 5, a pump 6, and a filter 7.

  In the compression device, when the pair of screw rotors 10 are rotationally driven by the rotational drive of the driving machine 2, the gas sucked from the suction port 50 a between the rotor main body 21 of the male rotor 20 and the rotor main body 31 of the female rotor 30. Is compressed. At this time, due to the pressure of the compressed gas, a force Fr (see FIG. 4) is applied to the rotor body 21 of the male rotor 20 and the rotor body 31 of the female rotor 30 so that the rotor bodies 21 and 31 are separated from each other. . Thereby, a radial load in the same direction (radially outward) as the direction of application of the force Fr acts on each of the radial bearings 41 to 44. In this compressor 1, since the pressure of gas becomes higher as it is closer to the discharge side, the first radial bearings 41, 41 located on the discharge side than the second radial bearings 42, 44 located on the suction side. A larger radial load acts on 43. For this reason, it is desirable that the radial load acting on the first radial bearings 41 and 43 is reduced.

  Simultaneously with the rotational driving of the pair of screw rotors 10, high-pressure oil that is a high-pressure fluid is supplied to the high-pressure chamber 54 a through the oil supply passage 4 and the high-pressure introduction passage 58. On the other hand, the low pressure chamber 54 b is opened to the atmospheric pressure through the low pressure communication channel 59. For this reason, due to the pressure difference between the high pressure chamber 54a and the low pressure chamber 54b, the inward force (hereinafter referred to as “load reducing force Fk”) from the high pressure chamber 54a toward the low pressure chamber 54b with respect to the outer portions 22b and 32b. ”) Works. More specifically, as shown in FIG. 2, the load reducing force Fk acts in a direction from the upper part on the outer side in the arrangement direction toward the lower part on the inner side in the arrangement direction. The direction of the load reducing force Fk acting on the outer portion 22b of the male rotor 20 is opposite to the direction of the radial load acting on the first radial bearing 41 on the male rotor 20 side, and acts on the outer portion 32b of the female rotor 30. The direction of the load reducing force Fk is opposite to the direction of the radial load acting on the first radial bearing 43 on the female rotor 30 side. In other words, the high pressure chamber 54a and the low pressure chamber 54b are arranged so that the direction in which each load reducing force Fk acts is opposite to the direction of the radial load acting on each first radial bearing 41, 43. . Therefore, the radial load acting on the first radial bearings 41 and 43 is reduced by the load reducing force Fk acting on the outer portions 22b and 32b. That is, the high pressure chamber 54a and the low pressure chamber 54b function as a load reduction mechanism that reduces the radial load acting on each of the first radial bearings 41 and 43. The high-pressure oil supplied to the high pressure chamber 54a flows into the low pressure chamber 54b through the gap between the outer portion 22b of the male rotor 20 and the partition portion 55 and the gap between the outer portion 32b of the female rotor 30 and the partition portion 56. Then, it flows out of the sub casing 54 through the low pressure introduction flow path 59.

  Here, paying attention to the male rotor 20 side, the principle that the load reducing force Fk reduces the radial load acting on the first radial bearing 41 will be described with reference to FIG. When the compressor 1 is driven, a force Fr in a direction away from the rotor body 31 of the female rotor 30 (upward in FIG. 4) acts on the rotor body 21 of the male rotor 20. Then, a portion of the first shaft 22 that is supported by the first radial bearing 41 (hereinafter referred to as “inner portion 22a”) has a force F1 that is opposite to the direction in which the force Fr acts from the first radial bearing 41. Works. Similarly, a portion of the second shaft 26 that is supported by the second radial bearing 42 (hereinafter referred to as “inner portion 26 a”) has a force opposite to the direction in which the force Fr acts from the second radial bearing 42. F2 acts. Then, due to the pressure difference between the high pressure chamber 54a and the low pressure chamber 54b, the load reducing force Fk inward in the alignment direction (opposite to the direction in which the force Fr is applied) acts on the outer portion 22b of the first shaft 22. The balance equation of the moment around the inner portion 26a of the second shaft 26 in this state is as follows.

  Fr × (L2−L1) = F1 × L2 + Fk × (L3 + L2) (1)

  In the above formula (1), L1 is the distance between the inner portion 22a of the first shaft 22 and the central portion of the rotor body 21, and L2 is the inner portion 22a of the first shaft 22 and the inner portion 26a of the second shaft 26. , L3 is a distance between the inner part 22a and the outer part 22b of the first shaft 22. From the above equation (1), the force F1 is expressed as the following equation (2).

  F1 = {Fr (L2-L1) -Fk (L3 + L2)} / L2 (2)

  From the above equation (2), it can be seen that the force F1 (radial load acting on the first radial bearing 41) is smaller than the force Fr by the amount due to the load reducing force Fk.

  Here, as in the invention described in Patent Document 1, when the load reducing force Fk is applied directly to the inner portion 22a of the first shaft 22, the force F1 ′ acting on the inner portion 22a is expressed by the above formula ( Since it is sufficient to set L3 = 0 in 2), the following expression (3) is obtained.

  F1 ′ = {Fr (L2-L1) −Fk × L2} / L2 (3)

  From Formula (2) and Formula (3), when the load reducing force Fk acts on the outer portion 22b of the first shaft 22 as in the present compressor 1, the force F1 acting on the inner portion 22a, As described above, the difference ΔF1 from the force F1 ′ acting on the inner portion 22a when the load reducing force Fk is directly applied to the inner portion 22a of the first shaft 22 is expressed by the following equation (4). .

  ΔF1 = F1′−F1 = Fk × L3 / L2 (4)

  Thus, in this compressor 1, compared with the case where the load reduction force Fk is made to act directly on the inner side part 22a of the 1st axis | shaft 22, force F1 can be reduced more largely. Therefore, the gas can be compressed to a higher pressure. Moreover, in the present compressor 1, since the load reducing force Fk is applied to the outer portion 22b of the first shaft 22, the inner portion 22a of the first shaft 22 can be easily obtained without applying special processing to the first radial bearing 41. The force F1 acting on the part can be reduced.

  Moreover, in this embodiment, since the outer diameter of the outer side part 22b is larger than the outer diameter of the other part in the longitudinal direction of the 1st axis | shaft 22, a pressure receiving area can be enlarged. For this reason, the load reducing force Fk can be easily ensured.

  The same applies to the female rotor 30 side.

  Moreover, in the said embodiment, since the subcasing 54 is detachable with respect to the rotor casing 52, a load reduction mechanism can be added to the said existing compressor, utilizing the rotor casing of the existing compressor as it is. It becomes possible.

  In the above embodiment, the oil discharged from the compressor is supplied to the high pressure chamber 54a as a high pressure fluid, so that a dedicated supply source for supplying the high pressure fluid to the high pressure chamber 54a can be omitted.

  As mentioned above, although embodiment of this invention was described, it should be thought that embodiment disclosed this time is an illustration and restrictive at no points. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  In the compressor 1 of the above embodiment, an example in which the load reducing force Fk is applied to the outer portion 22b of the male rotor 20 and the outer portion 32b of the female rotor 30 is shown. However, as shown in FIG. The load reducing force Fk may be applied to the outer portion 26b of the 20 second shaft 26 and the outer portion of the second shaft 36 of the female rotor 30, respectively. In FIG. 5, only the male rotor 20 is shown. In this example, the direction of the load reducing force Fk is the same as the direction of the force Fr acting on the rotor body 21. In this case, the difference ΔF1 is expressed by the following equation (5) from the balance equation of moments around the inner portion 26a of the second shaft 26.

  ΔF1 = Fk × (L3−L2) / L2 (5)

  Therefore, also in this case, the same effect as described above can be obtained.

  Moreover, although the example which makes the load reduction force Fk act only on the 1st axis | shaft was shown in the said embodiment, you may make the load reduction force Fk act on both a 1st axis | shaft and a 2nd axis | shaft. Further, the load reducing force Fk may be applied to only one of the male rotor 20 and the female rotor 30.

  Moreover, in the said embodiment, although the twin screw compressor which has a pair of screw rotor 10 was illustrated, the single screw compressor which has a single screw rotor may be sufficient. In addition to the high-pressure oil, other high-pressure fluid such as compressed gas may be introduced into the high-pressure chamber 54a.

DESCRIPTION OF SYMBOLS 1 Compressor 4 Oil supply flow path 10 A pair of screw rotor 20 Male rotor 21 Rotor main body 22 1st axis | shaft 22a Inner site | part 22b Outer site | part 26 2nd axis | shaft 26a Inner site | part 30 Female rotor 31 Rotor main body 32 1st axis | shaft 32a Inner site | part 32b Outer side Part 36 Second shaft 36a Inner part 41, 43 First radial bearing 42, 44 Second radial bearing 50 Casing 52 Rotor casing 53 Opening 54 Subcasing 54a High pressure chamber 54b Low pressure chamber 58 High pressure introduction flow path

Claims (6)

A rotor body which is a screw part;
A casing covering the rotor body;
A discharge port that is located at a front portion in the longitudinal direction of the rotor body and discharges the gas compressed by the rotor body;
Located at the rear part in the longitudinal direction of the rotor body, and a suction port for sucking the gas,
A first shaft extending forward from the rotor body;
A second shaft extending rearward from the rotor body;
A first radial bearing that supports the first shaft in a radial direction;
A second radial bearing that supports the second shaft in a radial direction;
A load reducing mechanism for reducing a radial load acting on the first radial bearing;
With
The load reducing mechanism applies a load reducing force including a component in a direction opposite to a radial component of a force acting on the rotor body on the front side of the first radial bearing to the first shaft; or The compressor causes a load reducing force including a component in the same direction as the component in the radial direction of the force acting on the rotor body behind the second bearing to act on the second shaft. The compressor according to claim 1,
The load reducing mechanism includes a high pressure chamber capable of accommodating a high pressure fluid around the first shaft, and a low pressure chamber having a lower pressure than the high pressure chamber;
Due to the pressure difference between the high pressure chamber and the low pressure chamber, the load reducing force including a component in a direction opposite to a radial component of a force acting on the rotor body in front of the first radial bearing. Compressor to generate. The compressor according to claim 2, wherein
A compressor in which an outer diameter of a portion of the first shaft in contact with the high pressure chamber is larger than an outer diameter of another portion of the first shaft in the longitudinal direction. The compressor according to claim 2 or 3,
The casing is
A rotor casing that houses the rotor body and the first radial bearing and has an opening that opens forward;
A sub-casing that forms the high-pressure chamber and the low-pressure chamber and closes the opening;
With
The sub casing is a compressor that is detachably attached to the rotor casing. The compressor according to claim 4, wherein
The sub-casing
A compressor having a high-pressure introduction channel for introducing oil contained in a fluid discharged from the compressor into the high-pressure chamber as the high-pressure fluid. The compressor according to any one of claims 2 to 5,
Another rotor body which is a screw part meshing with the rotor body;
Another first shaft extending forward from the other rotor body;
Another second shaft extending rearward from the other rotor body;
Another first radial bearing for supporting the other first shaft in a radial direction;
Another second radial bearing for supporting the other second shaft in a radial direction;
A load reducing mechanism for reducing a radial load acting on the other first radial bearing;
With
The load reducing mechanism includes another high pressure chamber capable of accommodating a high pressure fluid around the other first shaft, and another low pressure chamber having a lower pressure than the other high pressure chamber,
Due to the pressure difference between the other high-pressure chamber and the other low-pressure chamber, the radial component of the force acting on the other rotor body in front of the other first radial bearing is opposite to that of the other first radial bearing. A compressor that generates the load reducing force including a component.

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