Compressor

Abstract

To prevent a bearing from being affected by thermal shrinkage generating on the whole circumference of the bearing, while stably supporting the bearing.SOLUTION: A compressor includes a tilting pad bearing capable of supporting a rotating shaft in a casing. The tilting pad bearing includes a bearing pad in slide-contact with an outer peripheral surface of the rotating shaft, and a pivot for slidably supporting the bearing pad. The casing has an annular groove portion formed in a manner of being recessed in an axial direction and extending in a circumferential direction, and a connecting portion connecting an inner peripheral region at an inner side in a radial direction to the annular groove portion and an outer peripheral region at an outer side in the radial direction to the annular groove portion in a manner of crossing a part of the annular groove portion, and the connecting portion is disposed on a position overlapped to the pivot at a position in a width direction orthogonal to a vertical direction, when observed from the axial direction.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a compressor.

Background Art

[0002] In a compressor such as a centrifugal compressor, for example, a low-temperature working fluid of 0°C or lower such as ethylene gas or propylene gas may be compressed. When the low-temperature working fluid flows through the flow path of the compressor, the temperature of members such as the casing of the compressor disposed around the flow path and the bearings that support the rotating shaft decreases. As a result, thermal contraction occurs in these members. The occurrence of thermal contraction may reduce the clearance between the rotating shaft and the bearing, and there is a possibility that seizure may occur in the bearing.

[0003] On the other hand, Patent Document 1 discloses a configuration in which a groove extending along the vertical direction and the longitudinal direction of the rotating shaft is formed at one end of the casing of the centrifugal compressor, located outside the diameter of the bearing. In such a configuration, the thermal contraction of the casing caused by sucking in the low-temperature working fluid is blocked by the groove, and a decrease in the clearance between the rotating shaft and the bearing is prevented.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the casing of the centrifugal compressor described in Patent Document 1 is of a horizontally split type and is split vertically into an upper half casing and a lower half casing. The bearing is held with respect to the lower half casing via a bearing holder. In such a configuration, the bearing is not in direct contact with the upper half casing and is less affected by the thermal contraction of the upper half casing. For this reason, the groove is formed only in the lower half casing.

[0006] On the one hand, when the casing of the compressor is of a vertically split type, the casing is split so that annular members such as the head and the diaphragm are arranged horizontally. In such a configuration, the bearing is supported by a semi-circular bearing support portion formed on the annular head. Therefore, the bearing receives the influence of the thermal contraction of the head over the entire circumference of the bearing.

[0007] The present disclosure has been made to solve the above problems, and an object thereof is to provide a compressor capable of stably supporting a bearing while suppressing the influence of thermal contraction occurring over the entire circumference of the bearing from reaching the bearing.

Means for Solving the Problems

[0008] To solve the above problems, a compressor according to the present disclosure has a rotating shaft extending in the axial direction in which the axis extends, a rotor rotatable about the axis, a casing covering the rotor from the outside in the radial direction with respect to the axis and having a suction port for taking in a working fluid therein, and a tilting pad bearing capable of supporting the rotating shaft within the casing. The tilting pad bearing includes a plurality of bearing pads arranged at intervals in the circumferential direction about the axis and in sliding contact with the outer peripheral surface of the rotating shaft, and a pivot supported by the casing and swingably supporting the bearing pads. The casing includes a cylindrical outer casing extending in the axial direction, a suction-side head that closes the opening of the outer casing on the first side in the axial direction, and a discharge-side head that closes the opening of the outer casing on the second side in the axial direction. The suction-side head is disposed at a position closer to the suction port than the discharge-side head. The casing is formed with an annular groove portion that is recessed in the axial direction and extends in the circumferential direction at an end near the suction port and at a position separated from the tilting pad bearing toward the outside in the radial direction. When viewed from the axial direction, the casing has a connecting portion that connects an inner peripheral region on the inner side in the radial direction with respect to the annular groove portion and an outer peripheral region on the outer side in the radial direction with respect to the annular groove portion so as to cross a part of the annular groove portion in the circumferential direction. The connecting portion is arranged at a position where the width direction perpendicular to the vertical direction overlaps with the pivot when viewed from the axial direction. The annular groove portion is formed only in the suction-side head of the casing.

Advantages of the Invention

[0009] According to the compressor of the present disclosure, while stably supporting the bearing, it is possible to suppress the influence of thermal shrinkage occurring around the entire circumference of the bearing from reaching the bearing.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0011] Hereinafter, with reference to the accompanying drawings, modes for implementing the compressor according to the present disclosure will be described. However, the present disclosure is not limited to only this embodiment.

[0012] (Configuration of Compressor) The centrifugal compressor (compressor) 1, which is the compressor of the present embodiment, compresses a low-temperature gas of 0°C or lower as the working fluid G. The centrifugal compressor 1 of the present embodiment is, for example, a single-shaft multi-stage centrifugal compressor (multi-stage centrifugal compressor) that compresses ethylene gas or propylene gas. As shown in FIG. 1, the centrifugal compressor 1 mainly includes a casing 2, a rotor 3, a seal portion 5, a first bearing portion 91, and a second bearing portion 92.

[0013] In the following, the direction in which the axis O of the rotor 3 described later extends is defined as the axial direction Da. The radial direction with respect to the axis O is simply referred to as the radial direction Dr. Also, the direction around the rotor 3 centered on the axis O is defined as the circumferential direction Dc.

[0014] (Configuration of Casing) The casing 2 covers the rotor 3 from the outer side Dro in the radial direction Dr. The casing 2 of the present embodiment has an outer casing 21, a plurality of diaphragms 22, and a pair of heads 23.

[0015] The outer casing 21 has a cylindrical shape centered on a central axis arranged in the same manner as the axis O of the rotor 3. The first side Da1 (one side) in the axial direction Da of the outer casing 21 is open with a size that allows the bundle 100 described later to be inserted. An end plate 210 is formed on the second side Da2 (the other side) in the axial direction Da of the outer casing 21. The end plate 210 has a plate shape that spreads so as to be orthogonal to the axial direction Da.

[0016] The plurality of diaphragms 22 are arranged so as to cover the rotor 3 from the outer side Dro in the radial direction Dr. The plurality of diaphragms 22 are arranged inside the outer casing 21. The diaphragm 22 has an annular shape centered on the axis O. The plurality of diaphragms 22 are laminated so as to form a cylindrical shape extending in the axial direction Da. Between adjacent diaphragms 22, the outer peripheral surfaces are fixed to each other by welding or bolts. By fixing the plurality of diaphragms 22 to each other, a casing flow path 25 for introducing into the impeller 32 is formed inside. Further, the plurality of diaphragms 22, together with the head 23, the rotor 3, the seal portion 5, the first bearing portion 91, and the second bearing portion 92, constitute a bundle 100. The bundle 100 is housed inside the outer casing 21. In the bundle 100, the rotor 3, the plurality of diaphragms 22, the plurality of heads 23, the seal portion 5, the first bearing portion 91, and the second bearing portion 92 are in a state where they can move together so as to be integrated.

[0017] Inside the casing 2, a casing flow path 25 for circulating the working fluid G to be compressed is formed. On the first side Da1 in the axial direction Da, a suction port 7 for allowing the working fluid G to flow from the outside into the casing flow path 25 formed inside the casing 2 is formed. In the present embodiment, the suction port 7 takes in the working fluid G from below in the vertical direction Dv in the casing 2 into the lower half of the casing 2. The temperature of the working fluid G at the suction port 7 is, for example, 0°C or lower. Further, on the second side Da2 in the axial direction Da of the casing 2, a discharge port 8 for discharging the working fluid G to the outside is formed continuously with the casing flow path 25. The discharge port 8 discharges the working fluid G compressed by flowing through the casing flow path 25 to the outside of the casing 2 from below in the vertical direction Dv in the casing 2.

[0018] The pair of heads 23 are annular members and are arranged inside the outer casing 21. The heads 23 are formed to have a size capable of closing the openings at both ends of the outer casing 21. As the heads 23 of the present embodiment, a suction-side head 231 arranged on the first side Da1 in the axial direction Da with respect to the plurality of diaphragms 22 and a discharge-side head 232 arranged on the second side Da2 in the axial direction Da with respect to the plurality of diaphragms 22 are provided.

[0019] The suction-side head 231 is arranged at a position closer to the suction port 7 than the discharge-side head 232. The suction-side head 231 forms the suction port 7 together with the diaphragm 22 arranged on the most first side Da1 in the axial direction Da. The suction-side head 231 is fixed to the integrated plurality of diaphragms 22 by bolts or the like. Thereby, the suction-side head 231 is integrated with the diaphragm 22.

[0020] The suction-side head 231 of the present embodiment has a recess 237. The recess 237 is recessed toward the second side Da2 in the axial direction Da so as to form a circular shape centered on the axis O when viewed from the first side Da1 in the axial direction Da. The bottom surface 237b of the recess 237 is a plane orthogonal to the axis O.

[0021] The discharge-side head 232 is disposed at a position closer to the discharge port 8 than the suction-side head 231. The discharge-side head 232 forms the discharge port 8 together with the diaphragm 22 disposed on the second side Da2 in the axial direction Da. The discharge-side head 232 is fixed to the plurality of integrated diaphragms 22 by bolts or the like. Thereby, the discharge-side head 232 is integrated with the diaphragm 22.

[0022] (Configuration of Rotor) The rotor 3 is housed inside the casing 2. The rotor 3 is rotatable about the axis O. The rotor 3 of the present embodiment has a rotating shaft 31 and a plurality of impellers 32.

[0023] The rotating shaft 31 extends in a columnar shape in the axial direction Da about the axis O. Both ends 31a and 31b of the rotating shaft 31 in the axial direction Da project outward in the axial direction Da with respect to the casing 2. The first end 31a, which is the end on the first side Da1 in the axial direction Da of the rotating shaft 31, projects in the axial direction Da with respect to the suction-side head 231. The second end 31b, which is the second side Da2 in the axial direction Da of the rotating shaft 31, projects in the axial direction Da with respect to the discharge-side head 232.

[0024] The impeller 32 is supported by the rotating shaft 31 so as to be rotatable about the axis O. The plurality of impellers 32 are arranged at intervals in the axial direction Da of the rotating shaft 31. In FIG. 1, an example is shown in which six impellers 32 are formed, but at least one impeller 32 may be provided. Each impeller 32 compresses the gas by utilizing centrifugal force when rotating. The impeller 32 compresses the working fluid G sucked from the first side Da1 in the axial direction Da and discharges it to the outside Dro in the radial direction Dr.

[0025] In such a centrifugal compressor 1, the working fluid G is introduced into the casing flow path 25 from the suction port 7 that is closer to the first end portion 31a than the center position of the rotating shaft 31 in the axial direction Da. The working fluid G is compressed in each of the impellers 32 that rotate around the axis O together with the rotating shaft 31, flows from the inner side Dri in the radial direction Dr to the outer side Dro in the radial direction Dr, and is discharged into the casing flow path 25. The casing flow path 25 guides the working fluid G discharged from the upstream impeller 32 located on the first side Da1 in the axial direction Da to the downstream impeller 32 located on the second side Da2 in the axial direction Da. The working fluid G is compressed by passing through the impellers 32 provided in multiple stages and the casing flow path 25 within the casing 2. Thereafter, the working fluid G is sent out from the discharge port 8 that is closer to the second end portion 31b than the center position of the rotating shaft 31 in the axial direction Da.

[0026] (Configuration of the seal part) The seal part 5 seals between the rotor 3 and the casing 2. The seal part 5 of the present embodiment has a first seal part 51 disposed at a position closer to the first end portion 31a than the suction port 7 in the axial direction Da, and a second seal part 52 disposed at a position closer to the second end portion 31b than the discharge port 8 in the axial direction Da. The first seal part 51 is fixed to the suction side head 231. The first seal part seals between the suction side head 231 and the rotating shaft 31. The second seal part 52 is fixed to the discharge side head 232. The second seal part seals between the discharge side head 232 and the rotating shaft 31.

[0027] (Configuration of the first bearing part and the second bearing part) The first bearing portion 91 and the second bearing portion 92 support the rotor 3 so as to be rotatable about the axis O at both ends in the axial direction Da of the casing 2. The first bearing portion 91 as the bearing portion in the present embodiment is disposed at a position closer to the first end portion 31a than the suction port 7 in the axial direction Da. The first bearing portion 91 rotatably supports the rotating shaft 31 with respect to the suction side head 231. The second bearing portion 92 is disposed at a position closer to the second end portion 31b than the discharge port 8 in the axial direction Da. The second bearing portion 92 rotatably supports the rotating shaft 31 with respect to the discharge side head 232. Either one of the first bearing portion 91 and the second bearing portion 92 has a thrust bearing (not shown) in addition to the tilting pad bearing 95 described later.

[0028] As shown in FIGS. 2 and 3, the first bearing portion 91 and the second bearing portion 92 have tilting pad bearings 95. The tilting pad bearings 95 support the load (radial load) in the radial direction Dr of the rotor 3. The tilting pad bearings 95 include a plurality of bearing pads 96, a plurality of pivots 97, and a bearing housing 98. Hereinafter, in the present embodiment, the tilting pad bearing 95 of the first bearing portion 91 will be described as an example, but the tilting pad bearing 95 of the second bearing portion 92 has the same configuration except that it is fixed to the discharge side head 232.

[0029] Each bearing pad 96 is in sliding contact with the outer peripheral surface of the rotating shaft 31 via lubricating oil (not shown). The bearing pad 96 is formed in an arc shape in a cross-sectional view (a cross-section viewed from the axial direction Da) perpendicular to the axis O of the rotating shaft 31. The bearing pad 96 has a wide curved plate shape in the circumferential direction. The bearing pad 96 has a pad surface 96f facing the inner side Dri in the radial direction Dr and a pad back surface 96g facing the outer side Dro in the radial direction Dr. The pad surface 96f is a curved surface with a smaller curvature than the outer peripheral surface of the rotating shaft 31. Therefore, the pad surface 96f can be in sliding contact with the outer peripheral surface of the rotating shaft 31 in a line contact or a point contact. The plurality of bearing pads 96 are arranged at the same intervals in the circumferential direction Dc. In the present embodiment, five bearing pads 96 are arranged at equal intervals in the circumferential direction Dc. In the present embodiment, among the plurality of bearing pads 96, the lowermost bearing pad 96 is located directly below the rotating shaft 31 in the vertical direction Dv (directly below the axis O).

[0030] The pivot 97 supports the bearing pad 96 so as to be swingable. One pivot 97 is arranged on the outer side Dro in the radial direction Dr with respect to the bearing pad 96 corresponding to one bearing pad 96. The pivot 97 is fixed to the bearing housing 98. That is, the pivot 97 is indirectly supported by the casing 2 via the bearing housing 98. The pivot 97 point-supports or line-supports the pad back surface 96g of the bearing pad 96. Further, the pivot 97 that supports the bearing pad 96 located directly below the rotating shaft 31 in the vertical direction Dv (directly below the axis O) is located directly below the axis O. Further, the center of gravity of the rotating shaft 31 is below the axis O, which is the center in the width direction Dw perpendicular to the vertical direction Dv. Therefore, the pivot 97 located at the lowermost position in the vertical direction Dv in the tilting pad bearing 95 is the load support point at which the tilting pad bearing 95 receives the load of the rotating shaft 31.

[0031] The bearing housing 98 is formed in an annular shape centered on the axis O. The bearing housing 98 is fixed to the suction-side head 231 of the casing 2 over the entire circumference. The bearing housing 98 is housed in a hole recessed from the bottom surface 237b of the recess 237 when viewed from the axial direction Da. That is, the tilting pad bearing 95 is arranged so as to fit within the recess 237 when viewed from the axial direction Da. A pivot 97 is fixed to the inner peripheral surface of the bearing housing 98. An oil supply passage 981 for supplying lubricating oil between the rotating shaft 31 and the bearing pad 96 is formed in the bearing housing 98. The oil supply passage 981 is connected to a lubricating oil supply section 70 that supplies lubricating oil to the tilting pad bearing 95. The lubricating oil supply section 70 is connected to a supply source (not shown) of lubricating oil outside the casing 2. The lubricating oil supplied between the rotating shaft 31 and the bearing pad 96 from the lubricating oil supply section 70 via the oil supply passage 981 is discharged into the recess 237.

[0032] (Configuration of the annular groove portion and the connection portion) The casing 2 further has an annular groove portion 40A and a connection portion 42A. The annular groove portion 40A of the present embodiment is formed only in the suction-side head 231 that forms an end portion of the casing 2 close to the suction port 7. The annular groove portion 40A is formed at a position radially outward Dro of the tilting pad bearing 95. The annular groove portion 40A is formed so as to be recessed in the axial direction Da and extend in the circumferential direction Dc with respect to the surface of the suction-side head 231 facing the first side Da1 in the axial direction Da. Thereby, the annular groove portion 40A partitions the end surface of the suction-side head 231 when viewed from the axial direction Da into an inner peripheral region 27 radially inward Dri with respect to the annular groove portion 40A and an outer peripheral region 28 radially outward Dro with respect to the annular groove portion 40A.

[0033] The annular groove portion 40A of the present embodiment is formed in the suction-side head 231 so as to be disposed within the recess 237 when viewed from the first side Da1 in the axial direction Da. Therefore, the annular groove portion 40A is recessed in the axial direction Da from the bottom surface 237b of the recess 237. The annular groove portion 40A is formed in an arc shape centered on the axis O when viewed from the axial direction Da. The annular groove portion 40A opens at the bottom surface 237b so as to communicate with the space within the recess 237.

[0034] The connecting portion 42A is formed so as to cross a part of the annular groove portion 40A in the circumferential direction Dc when viewed from the axial direction Da. The connecting portion 42A connects the inner peripheral region 27 and the outer peripheral region 28 partitioned by the annular groove portion 40A when viewed from the axial direction Da. The connecting portion 42A is a region located on the extension line of the annular groove portion 40A extending in the circumferential direction Dc when viewed from the axial direction Da and in which the annular groove portion 40A is not formed. That is, the annular groove portion 40A is formed as a single groove so as to surround the tilting pad bearing 95 in the region other than the connecting portion 42A on the bottom surface 237b when viewed from the axial direction Da. Therefore, the bottom surface 237b connects the inner peripheral region 27 and the outer peripheral region 28 only through the connecting portion 42A. The connecting portion 42A is located below the vertical direction Dv with respect to the axis O when viewed from the axial direction Da.

[0035] Further, the connecting portion 42A is disposed at a position where the position in the width direction Dw overlaps with the pivot 97 when viewed from the axial direction Da. More specifically, the connecting portion 42A is disposed at a position where it overlaps with the pivot 97 which is the load support point of the tilting pad bearing 95 in the width direction Dw when viewed from the axial direction Da. Furthermore, the connecting portion 42A is formed at a position overlapping with the suction port 7 when viewed from the axial direction Da. That is, the connecting portion 42A is formed in the lower half (below the axis O) of the suction-side head 231 when viewed from the axial direction Da.

[0036] (Function and Effect) In the compressor 1 configured as described above, due to the influence of the temperature of the low-temperature working fluid G flowing in from the suction port 7, thermal contraction occurs circumferentially so as to push the tilting pad bearing 95 inward into the suction-side head 231. However, an annular groove portion 40A is formed at a position radially separated from the first bearing portion 91 by the radial direction Dr. As a result, the influence of thermal contraction is blocked by the annular groove portion 40A, and the contraction in the region Dri inside the radial direction Dr with respect to the annular groove portion 40A is suppressed. Therefore, in the suction-side head 231, the contraction in the inner peripheral region 27 where the tilting pad bearing 95 is fixed is suppressed compared to the outer peripheral region 28. Accordingly, it is possible to reduce the risk that the influence of the contraction of the suction-side head 231 reaches the tilting pad bearing 95 and the bearing clearance becomes narrow in the tilting pad bearing 95, resulting in seizure. Further, a connecting portion 42A that connects the inner peripheral region and the outer peripheral region is formed so as to cross a part of the annular groove portion 40A in the circumferential direction Dc. Therefore, the region where the connecting portion 42A is formed has higher rigidity than the region where the annular groove portion 40A is formed. Accordingly, by forming the connecting portion 42A, the tilting pad bearing 95 can be supported in a stable state as compared with the case where a groove is formed so as to surround the tilting pad bearing 95 over the entire circumference. Further, in the tilting pad bearing 95, the load received from the rotating shaft 31 acts most greatly on the suction-side head 231 at the position where the pivot 97 is disposed. The connecting portion 42A is disposed so as to overlap the position where such a pivot 97 is disposed. As a result, the connecting portion 42A can efficiently secure the rigidity required for the suction-side head 231 to support the load received from the rotating shaft 31. From these, while stably supporting the bearing, it is possible to suppress the influence of thermal contraction occurring over the entire circumference of the bearing from reaching the bearing.

[0037] In addition, the connection portion 42A is arranged at a position overlapping with the pivot 97 that is located at the lowermost position in the vertical direction Dv, which is the load support point, in the width direction Dw. Since the pivot 97 located at the lowermost position in the vertical direction Dv is a load support point, the load received from the rotating shaft 31 becomes the largest. The connection portion 42A is arranged so as to overlap such a lowermost pivot 97. As a result, the connection portion 42A can more efficiently secure the rigidity required for the suction-side head 231 to support the load received from the rotating shaft 31. Thereby, the bearing can be supported more stably.

[0038] In addition, when viewed from the axial direction Da, the annular groove portion 40A is formed as a single groove so that the regions other than the connection portion 42A surround the tilting pad bearing 95 on the bottom surface 237b. That is, when viewed from the axial direction Da, the annular groove portion 40A surrounds the tilting pad bearing 95 in the circumferential direction Dc in the regions other than the connection portion 42A. Therefore, the influence of the thermal contraction of the suction-side head 231 on the entire circumference of the tilting pad bearing 95 is less likely to reach the tilting pad bearing 95 in many regions in the circumferential direction Dc. Thereby, it is possible to effectively suppress the influence of the thermal contraction occurring on the entire circumference of the bearing from reaching the bearing.

[0039] In addition, when viewed from the first side Da1 in the axial direction Da, the annular groove portion 40A is formed so as to be disposed within the recess 237. The bottom surface 237b, which is the surface of the suction-side head 231 in which the recess 237 is formed, faces the outside of the casing 2 and faces the first side Da1 in the axial direction Da. For this reason, the inner surface forming the recess 237 is exposed to the external atmosphere (external air) where the compressor 1 is installed. As a result, the temperature is higher than that inside the casing 2. Furthermore, external air having a temperature higher than that of the working fluid G inside the casing 2 also flows into the annular groove portion 40A connected to such a recess 237. As a result, it becomes difficult for the temperature of the peripheral region of the suction-side head 231 where the annular groove portion 40A is formed to decrease, and thermal contraction is suppressed. Therefore, it is possible to more effectively suppress the influence of the thermal contraction of the casing 2 from reaching the bearing.

[0040] Further, the compressor 1 further includes a lubricating oil supply unit 70. Lubricating oil is supplied to the tilting pad bearing 95 by the lubricating oil supply unit 70 via the oil supply passage 981. The supplied lubricating oil is discharged into the recess 237 from the gap between the rotating shaft 31 and the tilting pad bearing 95 after being used in the tilting pad bearing 95. The discharged lubricating oil has been exposed to the rotating shaft 31 that rotates at high speed during the operation of the compressor 1, and thus has risen to a temperature higher than that of the working fluid G due to the heat generated between the rotating shaft 31 and the tilting pad bearing 95. Since the lubricating oil having risen in temperature in this way is discharged into the recess 237, the temperature of the inner surface of the recess 237 becomes higher. As a result, the influence of the thermal contraction of the casing 2 on the bearing can be more effectively suppressed.

[0041] Further, the suction port 7 takes in the working fluid G from below in the vertical direction Dv or into the casing 2. Thereby, when the working fluid G is at a low temperature, the thermal contraction becomes larger at the lower part of the suction side head 231 where the suction port 7 is located. On the other hand, the connecting portion 42A is located below the pivot 97 at the lowermost end below the vertical direction Dv with respect to the axis O when viewed from the axial direction Da. That is, the connecting portion 42A is formed at a position overlapping the suction port 7 when viewed from the axial direction Da. Therefore, the rigidity can be improved by the connecting portion 42A with respect to the region where the thermal contraction is the largest. Thereby, the bearing can be supported more stably.

[0042] Further, the fluid temperature at the suction port 7 of the working fluid G is 0°C or lower. By taking the working fluid G having a temperature of 0°C or lower into the casing 2, the thermal contraction of the casing 2, particularly the suction side head 231, becomes larger. In such a compressor 1, by providing the annular groove portion 40A, the influence of the thermal contraction of the casing 2 on the bearing can be effectively suppressed.

[0043] (Modification of the Embodiment) In the above-described embodiment, among the plurality of bearing pads 96 of the tilting pad bearing 95, one bearing pad 96 was arranged so as to be located directly below the axis O in the vertical direction Dv. However, the arrangement of the bearing pads 96 is not limited to such an arrangement.

[0044] For example, as shown in FIG. 4, among the plurality of bearing pads 96, the two bearing pads 96 located at the lowermost position may be arranged so as to be displaced to both sides in the width direction Dw with respect to directly below the axis O in the vertical direction Dv. That is, the plurality of bearing pads 96 are arranged so as not to overlap the region directly below the axis O. As a result, in the modified example, two of the lowermost bearing pads 96 among the plurality of bearing pads 96 are arranged at positions equidistant from the axis O in the width direction Dw.

[0045] When the tilting pad bearing 95 is arranged in this way, it is preferable that the connecting portion 42B is formed at a position overlapping the two lowermost bearing pads 96 among the plurality of tilting pad bearings 95 when viewed from the axial direction Da. In addition, it is more preferable that the connecting portion 42B is formed at a position overlapping the pivot 97 that supports the two lowermost bearing pads 96 when viewed from the axial direction Da. Therefore, the length of the circumferential direction Dc of the annular groove portion 40B in the modified example is shorter than that of the annular groove portion 40A in the embodiment.

[0046] Even in such a configuration, similar to the above-described embodiment, it is possible to suppress the influence of thermal shrinkage occurring over the entire circumference of the bearing from reaching the bearing while stably supporting the bearing.

[0047] (Other Embodiments) As described above, the embodiments of the present disclosure have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and design changes and the like within the scope not departing from the gist of the present disclosure are also included.

[0048] In the above embodiment, the centrifugal compressor 1 is exemplified as the compressor. However, the compressor is also applicable to compressors with other structures such as axial flow compressors other than the centrifugal compressor 1. Further, even in the case of a centrifugal compressor, the number of diaphragms 22, impellers 32, etc. is not limited to the structure of this embodiment.

[0049] Also, the structures of the annular groove portions 40A and 40B of the present embodiment are not limited to the structures of the present embodiment. For example, the regions where the connection portions 42A and 42B are formed may overlap with other pivots other than the lowermost pivot.

[0050] Also, the structure of the suction side head 231 is not limited to the structure of the present embodiment. For example, the recess 237 may not be formed in the suction side head 231.

[0051] Also, the tilting pad bearing 95 may be arranged in the second bearing portion 92, and the annular groove portions 40A, 40B, and the connection portions 42A, 42B may be formed in the discharge side head 23. In that case, the recess 237 may be formed in the discharge side head 23.

[0052] <Appendix> The compressor 1 described in the embodiment is understood as follows, for example.

[0053] (1) The compressor 1 according to the first aspect has a rotating shaft 31 extending in the axial direction Da in which the axis O extends, a rotor 3 rotatable about the axis O, a casing 2 that covers the rotor 3 from the outer side Dro in the radial direction Dr with respect to the axis O and has a suction port 7 for taking in the working fluid G therein, and a tilting pad bearing 95 capable of supporting the rotating shaft 31 within the casing 2. The tilting pad bearing 95 includes a plurality of bearing pads 96 arranged at intervals in the circumferential direction Dc about the axis O and in sliding contact with the outer peripheral surface of the rotating shaft 31, and a pivot 97 supported by the casing 2 and supporting the bearing pad 96 so as to be swingable. The casing 2 has annular groove portions 40A and 40B formed so as to be recessed in the axial direction Da and extend in the circumferential direction Dc at a position near the suction port 7 and away from the tilting pad bearing 95 on the outer side Dro in the radial direction Dr. When viewed from the axial direction Da, the casing 2 has a connection portion 42A that connects the inner peripheral region 27 on the inner side Dri in the radial direction Dr with respect to the annular groove portions 40A and 40B and the outer peripheral region 28 on the outer side Dro in the radial direction Dr with respect to the annular groove portions 40A and 40B so as to cross a part of the annular groove portions 40A and 40B in the circumferential direction Dc. The connection portion 42A is arranged at a position where the position in the width direction Dw orthogonal to the vertical direction overlaps with the pivot 97 when viewed from the axial direction Da.

[0054] As a result, the influence caused by thermal contraction is blocked by the annular groove portion 40A, and the contraction in the region inside Dri in the radial direction Dr with respect to the annular groove portion 40A is suppressed. Therefore, in the casing 2, compared with the outer peripheral region 28, the contraction in the inner peripheral region 27 where the tilting pad bearing 95 is fixed is suppressed. Accordingly, the influence of the contraction of the casing 2 on the tilting pad bearing 95 can be reduced, and in the tilting pad bearing 95, the risk that the bearing clearance becomes narrow and seizure occurs can be reduced. Further, the region where the connection portion 42A is formed has higher rigidity than the region where the annular groove portion 40A is formed. Therefore, compared with the case where a groove is formed so as to surround the tilting pad bearing 95 over the entire circumference, the tilting pad bearing 95 can be supported in a stable state. Also, in the tilting pad bearing 95, the load received from the rotating shaft 31 acts on the casing 2 most greatly at the position where the pivot 97 is arranged. The connection portion 42A is arranged so as to overlap with the position where such a pivot 97 is arranged. As a result, in order to support the load received from the rotating shaft 31, the connection portion 42A can efficiently secure the rigidity required for the casing 2. Due to these, while stably supporting the bearing, it is possible to suppress the influence of thermal contraction occurring over the entire circumference of the bearing from reaching the bearing.

[0055] (2) The compressor 1 according to the second aspect is the compressor 1 according to (1), wherein when viewed from the axial direction Da, the connection portion 42A is arranged at a position overlapping with the load support point where the tilting pad bearing 95 receives the load of the rotating shaft 31 in the width direction Dw.

[0056] As a result, the connection portion 42A is arranged so as to overlap with the pivot 97 which is the load support point. As a result, in order to support the load received from the rotating shaft 31, the connection portion 42A can more efficiently secure the rigidity required for the casing 2. Thereby, the bearing can be supported more stably.

[0057] (3) The compressor 1 according to the third aspect is the compressor 1 of (1) or (2), and in the annular groove portions 40A and 40B, when viewed from the axial direction Da, a region other than the connecting portion 42A is formed as a single groove so as to surround the tilting pad bearing 95.

[0058] As a result, when viewed from the axial direction Da, the annular groove portion 40A surrounds the tilting pad bearing 95 in a region other than the connecting portion 42A in the circumferential direction Dc. Therefore, the influence of the thermal shrinkage of the casing 2 on the entire circumference of the tilting pad bearing 95 is less likely to reach the tilting pad bearing 95 in many regions in the circumferential direction Dc. Accordingly, it is possible to effectively suppress the influence of the thermal shrinkage occurring on the entire circumference of the bearing from reaching the bearing.

[0059] (4) The compressor 1 according to the fourth aspect is any one of the compressors 1 of (1) to (3), and the casing 2 includes a cylindrical outer casing 21 extending in the axial direction Da, and a head 231 that closes the opening of the outer casing 21 on the first side Da1 in the axial direction Da. The head 231 has a recess 237 that is recessed in the axial direction Da so as to form a circular shape centered on the axis O when viewed from the first side Da1 in the axial direction Da. The annular groove portion 40A is formed in the head 231 so as to be disposed in the recess 237 when viewed from the first side Da1 in the axial direction Da.

[0060] As a result, the surface of the head 231 where the recess 237 is formed faces the outside of the casing 2 and faces the first side Da1 in the axial direction Da. For this reason, the inner surface forming the recess 237 is exposed to the external atmosphere (external air) where the compressor 1 is installed. Thus, when the working fluid G taken into the casing 2 is at a low temperature, the inner surface of the recess 237 has a higher temperature than that inside the casing 2. Further, external air having a higher temperature than the working fluid G in the casing 2 flows into the annular groove portion 40A connected to the recess 237. As a result, it becomes difficult for the temperature of the peripheral region of the head 231 where the annular groove portion 40A is formed to decrease, and thermal contraction is suppressed. Therefore, it is possible to more effectively suppress the influence of the thermal contraction of the casing 2 on the bearing.

[0061] (5) The compressor 1 according to the fifth aspect is the compressor 1 according to (4), further including a lubricating oil supply unit 70 that supplies lubricating oil to the tilting pad bearing 95, and the lubricating oil supplied to the tilting pad bearing 95 by the lubricating oil supply unit 70 is discharged into the recess 237.

[0062] As a result, the supplied lubricating oil is discharged into the recess 237 after being used in the tilting pad bearing 95. The discharged lubricating oil has been exposed to the rotating shaft 31 that rotates at high speed during the operation of the compressor 1, and has risen to a temperature higher than that of the working fluid G due to the heat generated between the rotating shaft 31 and the tilting pad bearing 95. Since the lubricating oil having risen in temperature in this way is discharged into the recess 237, the temperature of the inner surface of the recess 237 becomes higher. As a result, it is possible to more effectively suppress the influence of the thermal contraction of the casing 2 on the bearing.

[0063] (6) The compressor 1 according to the sixth aspect is the compressor 1 according to any one of (1) to (5), wherein the suction port 7 takes in the working fluid G from the outside of the casing 2 from below in the vertical direction Dv in the casing 2, and the connection portion 42A is formed at a position overlapping the suction port 7 when viewed from the axial direction Da.

[0064] Thus, when the working fluid G is at a low temperature, the thermal contraction becomes larger at the lower part of the casing 2 where the suction port 7 is located. The rigidity can be improved by the connecting portion 42A with respect to the region where such thermal contraction is the largest. Thereby, the bearing can be supported more stably.

Explanation of Signs

[0065] 1…Centrifugal compressor (compressor) 2…Casing 3…Rotor 5…Seal portion 51…First seal portion 52…Second seal portion 7…Suction port 8…Discharge port 100…Bundle 21…External casing 210…End plate 22…Diaphragm 23…Head 231…Suction side head 232…Discharge side head 237…Recess 237b…Bottom surface 27…Inner peripheral region 28…Outer peripheral region 25…Casing flow path 31…Rotating shaft 31a…First end 31b…Second end 32…Impeller 40A, 40B…Annular groove portion 42A, 42B…Connecting portion 70…Lubricating oil supply portion 91…First bearing portion 92…Second bearing portion 95…Tilting pad bearing 96…Bearing pad 96f…Pad surface 96g…Pad back surface 97…Pivot 98…Bearing housing 981…Oil supply path Da…Axial direction Da1…First side Da2…Second side Dc…Circumferential direction Dr…Radial direction Dri…Inner side Dro…Outer side Dw…Width direction G…Actuating fluid O…Axis

Claims

1. A compressor having a rotating shaft extending in the axial direction of the axis, a rotor rotatable about the axis, a casing covering the rotor from the outside in the radial direction with respect to the axis and having a suction port for taking in a working fluid therein, and a tilting pad bearing capable of supporting the rotating shaft within the casing. The tilting pad bearing includes a plurality of bearing pads arranged at intervals in the circumferential direction about the axis and in sliding contact with the outer peripheral surface of the rotating shaft, and a pivot supported by the casing and supporting the bearing pads so as to be swingable. The casing includes a cylindrical outer casing extending in the axial direction, a suction side head closing the opening of the outer casing on the first side in the axial direction, and a discharge side head closing the opening of the outer casing on the second side in the axial direction. The suction side head is disposed at a position closer to the suction port than the discharge side head. The casing has an annular groove portion formed to be recessed in the axial direction and extend in the circumferential direction at an end close to the suction port and at a position radially outside the tilting pad bearing, and has a connecting portion connecting an inner peripheral region radially inside the annular groove portion and an outer peripheral region radially outside the annular groove portion so as to cross a part of the annular groove portion in the circumferential direction when viewed from the axial direction. The connecting portion is disposed at a position where the position in the width direction orthogonal to the vertical direction overlaps with the pivot when viewed from the axial direction. The annular groove portion is formed only in the suction side head of the casing.

2. The compressor according to claim 1, wherein the connecting portion is disposed at a position overlapping with a load support point at which the tilting pad bearing receives a load of the rotating shaft in the width direction when viewed from the axial direction.

3. The compressor according to claim 1 or 2, wherein the annular groove portion is formed as a single groove such that a region other than the connecting portion surrounds the tilting pad bearing when viewed from the axial direction.

4. The suction side head has a recess recessed in the axial direction so as to form a circular shape centered on the axis when viewed from the first side in the axial direction. The compressor according to any one of claims 1 to 3, wherein the annular groove portion is formed in the suction-side head so as to be disposed within the recess when viewed from the first side in the axial direction.

5. The compressor further includes a lubricating oil supply unit that supplies lubricating oil to the tilting pad bearing. The compressor according to claim 4, wherein the lubricating oil supplied to the tilting pad bearing by the lubricating oil supply unit is discharged into the recess.

6. The suction port takes in the working fluid from outside the casing from below in the vertical direction in the casing. The compressor according to any one of claims 1 to 5, wherein the connection portion is formed at a position overlapping the suction port when viewed in the axial direction.

Images