JP6747355B2 - Centrifugal compressor - Google Patents

Description

The present invention relates to a centrifugal compressor.

A centrifugal compressor provided with a speed increaser is described in Patent Document 1, for example. The centrifugal compressor includes an impeller housing that houses an impeller and a speed increaser housing that houses a speed increasing mechanism. The speed increasing mechanism is provided between the ring member that rotates with the rotation of the low speed side shaft, the high speed side shaft that is arranged inside the ring member, and the ring member and the high speed side shaft. A plurality of rollers abutting on both of the shafts are provided. The impeller is integrated with the portion of the high-speed side shaft that is inserted into the impeller housing. Oil for lubrication is supplied to the speed increasing mechanism.

JP, 2016-194251, A

By the way, if the high-speed side shaft is tilted, the impeller may come into contact with the inner surface of the impeller housing. Therefore, in a centrifugal compressor equipped with a speed increaser, it is desired to stably support the high speed side shaft.

An object of the present invention is to provide a centrifugal compressor that can stably support a high speed side shaft.

A centrifugal compressor for solving the above-mentioned problems rotates with rotation of a low speed side shaft, has a ring member having an annular portion, a high speed side shaft arranged inside the annular portion, and the annular portion. A plurality of rollers provided between the high speed side shaft and contacting the annular portion and the high speed side shaft through oil, an impeller rotating integrally with the high speed side shaft, the ring member, the roller, and A speed increaser housing in which a part of the high speed side shaft is housed, and an impeller housing in which the impeller is housed, wherein the high speed side shaft is one of both end surfaces in the rotation axis direction of the roller. A first flange portion that faces a first end surface that is a surface of the first end portion, and a first flange portion that is provided farther from the impeller than the first flange portion in the rotation axis direction of the high-speed side shaft, A second flange portion facing a different second end face, and the outer peripheral surface of the roller is a portion of the peripheral surface of the high speed side shaft between the first flange portion and the second flange portion. A contact surface that comes into contact, a first non-contact surface that is a portion of the outer peripheral surface of the roller from the edge of the contact surface to the first end surface, and is separated from the peripheral surface of the high-speed side shaft, and the outer periphery of the roller. A portion of the surface from the edge of the contact surface to the second end surface, which is partitioned into a second non-contact surface separated from the peripheral surface of the high speed side shaft, and the contact surface in the rotation axis direction of the roller. The center position of is closer to the first flange portion than the center position of the roller.

According to this, by making the center position of the contact surface closer to the first flange portion than the center position of the roller, the area of the second non-contact surface can be made larger than the area of the first non-contact surface. .. Thereby, the gap defined between the second non-contact surface and the peripheral surface of the high speed side shaft should be made larger than the gap defined between the first non contact surface and the peripheral surface of the high speed side shaft. You can If the gap is large, oil easily enters, and as a result, the second flange portion is more likely to be supplied with oil than the first flange portion.

Here, in the centrifugal compressor, the second flange portion is pressed against the second end surface of the roller by the thrust force generated with the rotation of the impeller. Therefore, the second flange portion is more likely to generate heat and is more easily worn than the first flange portion. If the second flange portion is worn and the gap between the second flange portion and the second end surface becomes large, it may cause the high-speed side shaft to move in the rotation axis direction and may cause the high-speed side shaft to tilt. By making it easier to supply oil to the second flange portion, wear of the second flange portion can be suppressed, and the high speed side shaft can be prevented from moving in the rotation axis direction and the high speed side shaft from tilting. it can. Therefore, by suppressing the wear of the high speed side shaft, the high speed side shaft can be stably supported.

Further, by providing the first non-contact surface and the second non-contact surface, the contact area between the outer peripheral surface of the roller and the peripheral surface of the high speed side shaft can be reduced. In a traction drive type speed increaser in which the roller and the high-speed side shaft are brought into contact with each other via oil, it is necessary to solidify the oil on the outer peripheral surface of the roller and the peripheral surface of the high-speed side shaft. In order to solidify the oil, it is desirable to increase the surface pressure applied from the outer peripheral surface of the roller to the high speed side shaft. On the other hand, in order to increase the surface pressure, the overall dimension of the roller in the direction of the rotation axis is shortened, and the contact area between the peripheral surface of the high speed side shaft and the outer peripheral surface of the roller is reduced. However, the impeller and the inner surface of the impeller housing are likely to come into contact with each other, which is not preferable.

By providing the first non-contact surface and the second non-contact surface, by shifting the position of the contact surface, the outer peripheral surface of the roller and the peripheral surface of the high speed side shaft can be realized without shortening the overall dimension of the roller in the rotation axis direction. The contact area between the impeller and the inner surface of the impeller housing can be suppressed while ensuring a surface pressure for solidifying the oil by reducing the contact area with the impeller.

In the centrifugal compressor, a radial dimension of the roller from a boundary between the first non-contact surface and the contact surface to a boundary between the first non-contact surface and the first end surface is a first dimension, Assuming that the radial dimension of the roller from the boundary between the second non-contact surface and the contact surface to the boundary between the second non-contact surface and the second end surface is the second dimension, the second dimension is It may be longer than the first dimension.

According to this, by increasing the second dimension, it is possible to increase the area exposed in the gap in the second flange portion. The wear of the second flange portion can be further suppressed, and the high speed side shaft can be stably supported.

According to the present invention, the high-speed side shaft can be stably supported.

The schematic sectional drawing of a centrifugal compressor. FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, showing a part of the speed increaser. The perspective view which shows the relationship between a roller and a high speed side shaft. FIG. 4 is a sectional view taken along the line 4-4 of FIG. 2 showing a part of the speed increasing mechanism in a broken manner. Sectional drawing which shows the roller of a comparative example. Sectional drawing which shows the modification of a speed increasing mechanism. Sectional drawing which shows the modification of a speed increasing mechanism.

An embodiment of the centrifugal compressor will be described below. The centrifugal compressor is mounted on a fuel cell vehicle (FCV) that runs using a fuel cell as a power source, and supplies air to the fuel cell.

As shown in FIG. 1, the centrifugal compressor 10 includes a low speed side shaft 11 and a high speed side shaft 12, an electric motor 13 for rotating the low speed side shaft 11, and a high speed side shaft for increasing the rotation speed of the low speed side shaft 11. A gearbox 60 that is transmitted to 12 and an impeller 52 that compresses fluid (air in this embodiment) by rotation of the high-speed shaft 12 are provided.

The high-speed side shaft 12 includes a cylindrical shaft body 14, an annular first flange portion 15 radially protruding from the shaft body 14, and an annular second flange portion 16 radially protruding from the shaft body 14. With. The first flange portion 15 and the second flange portion 16 are arranged apart from each other in the rotation axis direction of the high speed side shaft 12. The shaft body 14 includes a support portion 17 that is a portion between the first flange portion 15 and the second flange portion 16, and a protrusion portion 18 that extends from the first flange portion 15 in the rotational axis direction opposite to the support portion 17. Equipped with. The second flange portion 16 is provided at an end portion opposite to the end portion on the impeller 52 side, of both ends of the high speed side shaft 12 in the rotation axis direction. The first flange portion 15 is provided closer to the impeller 52 than the second flange portion 16 in the rotation axis direction of the high speed side shaft 12. Both shafts 11 and 12 are made of, for example, a metal, specifically, iron or an alloy of iron.

The centrifugal compressor 10 constitutes an outer shell of the centrifugal compressor 10, and accommodates both shafts 11 and 12, the electric motor 13, and a speed increasing mechanism 61 forming a part of the speed increasing device 60. And a housing 20. The housing 20 has, for example, a substantially tubular shape (specifically, a cylindrical shape) as a whole.

The housing 20 includes a motor housing 21 in which the electric motor 13 is housed, a speed increaser housing 23 in which a speed increasing mechanism 61 is housed, and an impeller housing 50 in which a suction port 50a for sucking fluid is formed. The suction port 50a is provided on one end surface 20a of the housing 20 in the axial direction. The impeller housing 50, the gearbox housing 23, and the motor housing 21 are arranged in this order in the axial direction of the housing 20 as viewed from the suction port 50a. In the present embodiment, the speed increasing mechanism 61 and the speed increasing device housing 23 constitute the speed increasing device 60.

The motor housing 21 has a tubular shape (specifically, a cylindrical shape) having a bottom portion 22 as a whole. The outer surface of the bottom portion 22 of the motor housing 21 constitutes the other end surface 20b of the both end surfaces 20a, 20b of the housing 20 in the axial direction opposite to the one end surface 20a where the suction port 50a is located. The step-up gear housing 23 includes a main body portion 25 having a cylindrical shape (specifically, a cylindrical shape) having a bottom portion 24, and a closing portion 26 provided on the side opposite to the bottom portion 24 in the axial direction of the main body portion 25. Prepare

The motor housing 21 and the speed increaser housing 23 are connected in a state where the open end of the motor housing 21 abuts the bottom portion 24 of the main body portion 25. A motor housing chamber S1 in which the electric motor 13 is housed is formed by the inner surface of the motor housing 21 and the bottom surface 24a of the bottom portion 24 of the body portion 25 on the motor housing 21 side. The low speed side shaft 11 is housed in the motor housing chamber S1 in a state where the rotational axis direction of the low speed side shaft 11 and the axial direction of the housing 20 coincide with each other.

The low speed side shaft 11 is rotatably supported by the housing 20. The centrifugal compressor 10 includes a first bearing 31. The first bearing 31 is provided on the bottom portion 22 of the motor housing 21, and the first end 11 a of the low speed side shaft 11 is supported by the first bearing 31. A part of the first end portion 11 a is inserted through the first bearing 31 and into the bottom portion 22 of the motor housing 21.

The bottom portion 24 of the main body portion 25 includes a through hole 27 that is slightly larger than the second end portion 11b of the low speed side shaft 11 opposite to the first end portion 11a. The centrifugal compressor 10 includes a second bearing 32 and a seal member 33 in the through hole 27. The second end 11 b of the low speed side shaft 11 is supported by the second bearing 32. The seal member 33 restricts the oil O existing in the gearbox housing 23 from flowing into the motor housing chamber S1.

The second end 11 b of the low speed side shaft 11 is inserted into the through hole 27 of the main body 25, and a part of the low speed side shaft 11 is arranged inside the speed increaser housing 23.
The electric motor 13 includes a rotor 41 fixed to the low speed side shaft 11 and a stator 42 arranged outside the rotor 41 and fixed to the inner surface of the motor housing 21. The stator 42 includes a cylindrical stator core 43 and a coil 44 wound around the stator core 43. When the current flows through the coil 44, the rotor 41 and the low speed side shaft 11 rotate integrally.

The closing portion 26 has, for example, a disc shape having the same diameter as the speed increaser housing 23. The speed increaser housing 23 is assembled in a state in which the open end of the main body 25 and the first plate surface 26a of the plate surfaces 26a and 26b of the closing portion 26 in the axial direction face each other. As a result, the first plate surface 26a of the closed portion 26 and the inner surface of the speed increaser housing 23 form a speed increaser chamber S2 in which the speed increasing mechanism 61 is housed.

The closing portion 26 forming the speed increaser housing 23 includes an insertion hole 28 through which the high speed side shaft 12 forming a part of the speed increasing mechanism 61 can be inserted. The protruding portion 18 of the high speed side shaft 12 is inserted through the insertion hole 28 and protrudes from the speed increasing chamber S2. The 1st flange part 15, the 2nd flange part 16, and the support part 17 are arrange|positioned in the gearbox S2. The centrifugal compressor 10 includes, between the inner surface of the insertion hole 28 and the high speed side shaft 12, a seal member 34 that restricts the oil O in the speed increaser housing 23 from flowing out into the impeller housing 50.

The impeller housing 50 has a substantially cylindrical shape having a compression through hole 51 penetrating in the axial direction. One end face 50b in the axial direction of the impeller housing 50 constitutes one end face 20a in the axial direction of the housing 20, and the opening of the comp through hole 51 on the one end face 50b side functions as the suction port 50a.

The impeller housing 50 and the closing portion 26 include the other end surface 50c opposite to the one end surface 50b in the axial direction of the impeller housing 50, and the second plate surface 26b opposite to the first plate surface 26a of the closing portion 26. Are assembled in a state where they are butted against each other. As a result, the inner surface of the comp through hole 51 and the second plate surface 26b of the closing portion 26 form an impeller chamber S3 in which the impeller 52 is housed. That is, the comp through hole 51 functions as the suction port 50a and also as a partition of the impeller chamber S3. The suction port 50a and the impeller chamber S3 communicate with each other. The closing portion 26 located between the speed increaser chamber S2 and the impeller chamber S3 serves as a partition wall that partitions the two.

Here, the compression through hole 51 has a constant diameter from the suction port 50a to an intermediate position in the axial direction, and has a substantially truncated cone shape in which the diameter gradually increases from the intermediate position toward the closed portion 26. Therefore, the impeller chamber S3 defined by the inner surface of the comp through hole 51 has a substantially truncated cone shape.

The impeller 52 has a tubular shape whose diameter is gradually reduced from the base end surface 52a toward the tip end surface 52b. The impeller 52 includes a shaft insertion hole 52c that extends in the rotation axis direction of the impeller 52 and that can insert the high-speed side shaft 12 therethrough.

The impeller 52 is attached to the high speed side shaft 12 so as to rotate integrally with the high speed side shaft 12 in a state where the protruding portion 18 of the high speed side shaft 12 is inserted into the shaft insertion hole 52c.

A back surface region S4 is defined between the base end surface 52a of the impeller 52 and the second plate surface 26b of the closing portion 26. The rotation of the high-speed shaft 12 rotates the impeller 52, and the fluid sucked from the suction port 50a is compressed.

The centrifugal compressor 10 also includes a diffuser channel 53 into which the fluid compressed by the impeller 52 flows, and a discharge chamber 54 into which the fluid that has passed through the diffuser channel 53 flows. The diffuser flow path 53 is continuous with an opening end of the comp through hole 51 on the second plate surface 26b side of the impeller housing 50 and faces the second plate surface 26b, and a second plate surface 26b of the closing portion 26. It is a flow path divided by. The diffuser flow passage 53 is arranged radially outside the high-speed side shaft 12 with respect to the impeller chamber S3, and is formed in an annular shape (specifically, an annular shape) so as to surround the impeller 52 (and the impeller chamber S3). .. The discharge chamber 54 is an annular shape that is arranged radially outside the high-speed side shaft 12 with respect to the diffuser flow path 53. The impeller chamber S3 and the discharge chamber 54 communicate with each other via a diffuser flow path 53. The fluid compressed by the impeller 52 is further compressed by passing through the diffuser flow path 53, flows into the discharge chamber 54, and is discharged from the discharge chamber 54.

Next, the speed increaser 60 will be described. The gearbox 60 of this embodiment is a so-called traction drive type (friction roller type).
As shown in FIGS. 1 and 2, the speed increasing mechanism 61 of the speed increaser 60 includes a ring member 62 connected to the second end 11 b of the low speed side shaft 11. The ring member 62 includes a disc-shaped base 63 connected to the second end 11b of the low-speed side shaft 11, and an annular ring-shaped portion 64 standing upright from the edge of the base 63. The inner diameter of the annular portion 64 is set to be longer than the diameter of the second end portion 11b of the low speed side shaft 11.

In the present embodiment, the ring member 62 is connected to the low speed side shaft 11 such that the rotation axis direction of the base 63 (the rotation axis direction of the ring member 62) and the rotation axis direction of the low speed side shaft 11 coincide with each other. The rotation axis direction of the annular portion 64 also matches the rotation axis direction of the low speed side shaft 11. The ring member 62 rotates as the low speed side shaft 11 rotates.

A part of the high speed side shaft 12 is arranged inside the annular portion 64 in the radial direction of the ring member 62. The speed increasing mechanism 61 is provided between the high speed side shaft 12 and the annular portion 64, and includes three rollers 71 that are in contact with both the annular portion 64 and the high speed side shaft 12.

As shown in FIGS. 3 and 4, the three rollers 71 have the same shape. Each roller 71 includes a cylindrical roller portion 72, a cylindrical first projection 73 projecting from a first end surface 72a of the roller portion 72 in the rotation axis direction, and a second end surface 72b of the roller portion 72 in the rotation axis direction. And a columnar second projection 74 that projects. The first end surface 72a and the second end surface 72b of the roller portion 72 are both end surfaces of the roller 71 in the rotation axis direction.

The first protrusion 73 and the second protrusion 74 have the same dimension in the rotation axis direction. The direction of the rotation axis of the roller portion 72, the direction of the rotation axis of the first protrusion 73, and the direction of the rotation axis of the second protrusion 74 match. Hereinafter, the rotation axis direction of the roller portion 72 will be referred to as the rotation axis direction Z of the roller 71.

The roller portion 72 includes a cylindrical contact portion 75, a first non-contact portion 76 having a diameter that gradually decreases from the contact portion 75 toward the first end surface 72a, and gradually from the contact portion 75 toward the second end surface 72b. And a second non-contact portion 77 having a smaller diameter. The diameter of the contact portion 75 (the length in the direction orthogonal to the rotation axis direction Z) is set to be longer than the diameter of the support portion 17 of the high speed side shaft 12. It can be said that the first end surface 72a is an end surface of the first non-contact portion 76 in the rotation axis direction Z. It can be said that the second end surface 72b is an end surface of the second non-contact portion 77 in the rotation axis direction Z. The distance between the first end surface 72a and the second end surface 72b in the rotation axis direction Z is slightly shorter than the dimension of the support portion 17 in the rotation axis direction.

The roller portion 72 includes a contact surface A, a first non-contact surface B1 and a second non-contact surface B2 on the outer peripheral surface. The contact surface A is the outer peripheral surface of the contact portion 75, the first non-contact surface B1 is the outer peripheral surface of the first non-contact portion 76, and the second non-contact surface B2 is the outer peripheral surface of the second non-contact portion 77. is there.

The first non-contact surface B1 is a surface extending from the edge of the contact surface A to the first end surface 72a. The first non-contact surface B1 has a rounded shape (arc shape) that is convex outward in the radial direction. The second non-contact surface B2 is a surface extending from the edge of the contact surface A to the second end surface 72b. The second non-contact surface B2 has a rounded shape (arcuate shape) that is convex outward in the radial direction.

The dimension of the first non-contact surface B1 in the rotation axis direction Z is shorter than the dimension of the second non-contact surface B2 in the rotation axis direction Z. Accordingly, the center position CP1 of the contact surface A in the rotation axis direction Z is closer to the first end surface 72a than the center position CP2 of the roller 71 in the rotation axis direction Z.

The radial dimension of the roller 71 from the boundary P1 between the first non-contact surface B1 and the contact surface A to the boundary P2 between the first non-contact surface B1 and the first end surface 72a is defined as the first dimension L1, and the second non- The radial dimension of the roller 71 from the boundary P3 between the contact surface B2 and the contact surface A to the boundary P4 between the second non-contact surface B2 and the second end surface 72b is defined as a second dimension L2. The second dimension L2 is longer than the first dimension L1. In other words, the diameter of the second end surface 72b, which is the minimum diameter of the second non-contact portion 77, is shorter than the diameter of the first end surface 72a, which is the minimum diameter of the first non-contact portion 76. Each roller 71 is made of, for example, a metal, and specifically, is made of the same metal as the high-speed side shaft 12, for example, iron or an alloy of iron.

The rotation axis direction Z of the roller portion 72 and the rotation axis direction of the high speed side shaft 12 coincide with each other. The plurality of rollers 71 are arranged side by side at intervals in the circumferential direction of the high-speed side shaft 12.

The roller 71 is arranged so that the roller portion 72 is inserted between the first flange portion 15 and the second flange portion 16. The roller portion 72 is arranged such that the first end surface 72 a faces the first flange portion 15 and the second end surface 72 b faces the second flange portion 16. The first non-contact surface B1 is located on the first flange portion 15 side, and the second non-contact surface B2 is located on the second flange portion 16 side with the contact surface A interposed therebetween. Further, the center position CP1 of the contact surface A in the rotation axis direction Z is located closer to the first flange portion 15 side than the center position CP2 of the roller 71 in the rotation axis direction Z.

Since the first non-contact surface B1 is separated from the peripheral surface of the support portion 17, a first area is surrounded by the peripheral surface of the support portion 17, the first non-contact surface B1, and the first flange portion 15. A gap C1 is defined. Since the second non-contact surface B2 is separated from the peripheral surface of the support portion 17, the second peripheral surface of the support portion 17, the second non-contact surface B2, and the second flange portion 16 are surrounded by a second area. A gap C2 is defined. The second gap C2 is larger than the first gap C1.

Further, by providing the non-contact surfaces B1 and B2, compared with the case where the entire outer peripheral surface of the roller portion 72 is brought into contact with the peripheral surface of the support portion 17, the outer peripheral surface of the roller portion 72 and the peripheral surface of the support portion 17 are compared. The contact area with is small. Therefore, it can be said that the surface pressure applied from the roller portion 72 to the support portion 17 is larger than that when the entire outer peripheral surface of the roller portion 72 is brought into contact with the peripheral surface of the support portion 17.

Here, when the dimension of the contact surface A in the rotation axis direction Z is excessively shortened, the surface pressure significantly increases, and the high-speed shaft 12 is plastically deformed. More specifically, the contact area of the high-speed side shaft 12 whose outer peripheral surface contacts the outer peripheral surface of the roller 71 is smaller than that of the annular portion 64 whose inner peripheral surface contacts the outer peripheral surface of the roller 71, and the surface pressure increases. It's easy to do. Therefore, if the dimension of the contact surface A in the rotation axis direction Z is excessively reduced, the surface pressure excessively increases, which causes plastic deformation.

Further, the high-speed side shaft 12 is not supported by bearings but is supported by the holding force of the rollers 71, and the rollers 71 have minute dimensional differences due to manufacturing tolerances. There are many elements in which the shaft of the high speed side shaft 12 is deviated. If the contact area between the roller 71 and the peripheral surface of the high speed side shaft 12 is excessively small, the high speed side shaft 12 may not be stably supported when the impeller 52 rotates.

From the above factors, it is desirable that the dimension of the contact surface A in the rotation axis direction Z is, for example, 30% to 90% of the dimension of the support portion 17 in the rotation axis direction Z.
As shown in FIGS. 1 and 2, the speed increasing mechanism 61 includes a support member 80 that cooperates with the closing portion 26 to rotatably support the rollers 71. The support member 80 is arranged in the annular portion 64. The support member 80 includes a disc-shaped support base 81 that is slightly smaller than the annular portion 64, and three columnar columnar members 82 that stand upright from the support base 81. The support base 81 is arranged to face the closing portion 26 in the rotation axis direction Z. The three columnar members 82 are erected from the facing plate surface 81a of the support base 81 facing the first plate surface 26a of the closing portion 26 toward the closing portion 26, and are adjacent to the inner peripheral surface of the annular portion 64. It is formed so as to fill three spaces defined by the outer peripheral surfaces of the two roller portions 72.

As shown in FIGS. 1 and 2, the support member 80 includes a screw hole 84 into which each bolt 83 can be screwed, in each columnar member 82. The closing portion 26 includes a screw hole 85 corresponding to the screw hole 84 and communicating with the screw hole 84. Each columnar member 82 is arranged such that the screw hole 84 and the screw hole 85 communicate with each other, and the tip end surface of each columnar member 82 abuts against the first plate surface 26a. The bolt 83 is screwed so as to straddle 84 and the screw hole 85, and is fixed to the closing portion 26.

The speed increaser 60 includes a first roller bearing 78 and a second roller bearing 79 that rotatably support the roller 71. The first roller bearing 78 and the second roller bearing 79 are bearings. The first roller bearing 78 is arranged in the closing portion 26. The second roller bearing 79 is arranged on the support base 81. The roller 71 is disposed between the blocking portion 26 and the support base 81 by being supported by the first roller bearing 78 and the second roller bearing 79.

As shown in FIG. 2, the roller 71, the ring member 62, and the high speed side shaft 12 are unitized in a state where the roller portion 72, the high speed side shaft 12 and the annular portion 64 are pressed against each other. The shaft 12 is rotatably supported by the three roller portions 72. At the ring-side contact point Pa, which is the contact point between the outer peripheral surface of the roller portion 72 and the inner peripheral surface of the annular portion 64, and at the contact point between the outer peripheral surface of the roller portion 72 and the peripheral surface of the high-speed side shaft 12. A pressing load is applied to a certain shaft-side contact point Pb. The contact points Pa and Pb extend in the rotation axis direction Z.

As shown in FIG. 1, the centrifugal compressor 10 includes an oil supply mechanism 100 for supplying the oil O to the speed increasing mechanism 61. The oil supply mechanism 100 includes a pump 101 and an oil flow passage 102, and drives the pump 101 to circulate the oil O through the oil flow passage 102 to the speed increaser chamber S2.

The pump 101 is provided on the bottom portion 22 of the motor housing 21. The pump 101 of this embodiment is a positive displacement type. The pump 101 includes a housing 103 provided on the bottom 22 and a rotating body 104. The first end 11 a of the low speed side shaft 11 is connected to the rotating body 104.

The housing 20 includes a supply passage 105 that is a part of the oil flow passage 102 and a circulation passage 106 that is a part of the oil flow passage 102. The supply path 105 connects the housing portion 103 and the inside of the ring member 62. The circulation path 106 connects the speed increaser room S2 and the housing section 103. The centrifugal compressor 10 is used in a mode in which the communication path of the circulation path 106 in the speed increaser housing 23 is located vertically below. Therefore, in the speed increaser housing 23, the oil O is stored by gravity at the place where the circulation path 106 communicates.

Then, when the pump 101 is driven, the oil O flows in the order of the circulation path 106→the housing section 103→the supply path 105, and the oil O is supplied into the ring member 62.
Next, the operation of the centrifugal compressor 10 of this embodiment will be described.

When the roller 71 rotates as the electric motor 13 is driven, a thin film (elastic fluid lubrication film (EHL)) of the solidified oil O is formed at the ring-side contact point Pa and the shaft-side contact point Pb. In other words, the outer peripheral surface of the roller portion 72 and the inner peripheral surface of the annular portion 64 are in contact with each other through a thin film of oil O. Similarly, the peripheral surface of the high speed side shaft 12 and the outer peripheral surface of the roller portion 72 are in contact with each other through a thin film of the solidified oil O. Then, the rotational force of the roller 71 is transmitted to the high speed side shaft 12 via a thin film of the solidified oil O formed between the peripheral surface of the high speed side shaft 12 and the outer peripheral surface of the roller portion 72, and as a result, Therefore, the high speed side shaft 12 rotates. The annular portion 64 rotates at the same speed as the low speed side shaft 11, and each roller 71 rotates at a higher speed than the low speed side shaft 11. Further, the high speed side shaft 12 having a diameter smaller than that of the roller portion 72 rotates at a higher speed than the roller portion 72. From the above, the speed increaser 60 causes the high speed side shaft 12 to rotate at a higher speed than the low speed side shaft 11.

As described above, in the traction drive type speed increaser 60, the oil O is solidified at the contact points Pa and Pb, and the thin film of the solidified oil O causes the rotational force of the low speed side shaft 11 to be high. It will be transmitted to the side shaft 12. In order to solidify the oil O, it is desirable to increase the surface pressure applied from the roller 71 to the inner surface of the annular portion 64 and the peripheral surface of the high speed side shaft 12. In the present embodiment, by providing the non-contact surfaces B1 and B2, the contact area between the roller portion 72 and the peripheral surface of the high speed side shaft 12 is reduced. Therefore, the surface pressure is higher than that when the non-contact surfaces B1 and B2 are not provided. Therefore, the oil O is easily solidified at the contact points Pa and Pb.

If the overall dimension of the roller portion 72 in the rotation axis direction Z is shortened, the fulcrum when the high-speed side shaft 12 is tilted is closer to the second flange portion 16 side. Then, when the high-speed shaft 12 tilts, the amount of movement of the protrusion 18 increases, and the impeller 52 easily hits the inner surface of the impeller housing 50.

On the other hand, in the present embodiment, the contact area is reduced by providing the non-contact surfaces B1 and B2 without shortening the dimension of the roller portion 72 in the rotation axis direction Z. In addition, contact of the impeller 52 due to the inclination of the high speed side shaft 12 can be suppressed.

As shown in FIG. 5, in the roller 71 including the first non-contact surface B1 and the second non-contact surface B2, the center position CP11 of the contact surface A in the rotation axis direction Z and the rotation axis direction Z of the roller 71 are defined. When the center position CP12 is matched, the areas of the first non-contact surface B1 and the second non-contact surface B2 are the same. As a result, the first gap C11 and the second gap C12 have the same size.

On the other hand, as in the present embodiment, the center position CP1 of the contact surface A in the rotation axis direction Z is brought closer to the first flange portion 15 than the center position CP2 of the roller 71 in the rotation axis direction Z, whereby the second gap is formed. C2 can be made larger than the first gap C1. Accordingly, the oil O is more likely to enter the second gap C2 than the first gap C1, and the amount of the oil O supplied to the second flange portion 16 is larger than the oil O supplied to the first flange portion 15. Will increase.

Here, in the centrifugal compressor 10, the back surface region S4 is defined between the base end surface 52a of the impeller 52 and the closing portion 26 because it is necessary to prevent contact between the base end surface 52a of the impeller 52 and the closing portion 26. To be done. The fluid compressed by the impeller 52 enters the back surface region S4. Then, the impeller 52 is pushed toward the suction port 50a side by the compressed fluid, and the thrust force in the direction from the speed increasing chamber S2 to the impeller chamber S3 acts on the high speed side shaft 12. Due to this thrust force, the second flange portion 16 is pressed against the second end surface 72b of each roller portion 72, so that the second flange portion 16 is more likely to generate heat and is more easily worn than the first flange portion 15. The wear of the second flange portion 16 is suppressed by making it easier to supply the oil O to the second flange portion 16.

Further, since heat is generated by friction at the contact points Pa and Pb, heat is also generated at the shaft-side contact point Pb. By making the center position CP1 of the contact surface A in the rotation axis direction Z closer to the first flange portion 15, the heat generated at the shaft side contact portion Pb is less likely to be transferred to the second flange portion 16. As a result, it is possible to prevent heat from being transferred to the second flange portion 16 that is easily worn, and it is possible to further suppress wear of the second flange portion 16.

Therefore, according to the above embodiment, the following effects can be obtained.
(1) The center position CP1 of the contact surface A in the rotation axis direction Z is closer to the first flange portion 15 than the center position CP2 of the roller 71 in the rotation axis direction Z. As a result, the second gap C2 is larger than the first gap C1, and the oil O is easily supplied to the second flange portion 16 that is more likely to generate heat than the first flange portion 15. Therefore, the second flange portion 16 is less likely to be worn, and a gap is less likely to be formed between the second flange portion 16 and the second end surface 72b. Accordingly, it is possible to prevent the high-speed side shaft 12 from moving in the rotation axis direction and the high-speed side shaft 12 from tilting due to the gap between the second flange portion 16 and the second end surface 72b. That is, the high speed side shaft 12 can be stably supported.

(2) Further, the contact surface A is closer to the first flange portion 15 than the second flange portion 16. Therefore, the heat generated at the shaft-side contact portion Pb is less likely to be transmitted to the second flange portion 16, and the wear of the second flange portion 16 can be further suppressed.

(3) By providing the non-contact surfaces B1 and B2, the surface pressure for solidifying the oil O can be secured without shortening the dimension of the roller portion 72 in the rotation axis direction Z. Therefore, the impeller 52 is prevented from coming into contact with the inner surface of the impeller housing 50 due to the reduction in the overall dimension of the roller portion 72 in the rotation axis direction Z.

(4) In the centrifugal compressor 10 including the speed increaser 60, there are many elements in which the shaft of the high speed side shaft 12 is deviated. Since the dimension of the contact surface A in the rotation axis direction Z is not excessively short, the high speed side shaft 12 can be stably supported.

(5) The second dimension L2 is made longer than the first dimension L1. As a result, the area of the second flange portion 16 exposed in the second gap C2 can be increased. The oil O easily comes into contact with the second flange portion 16, and wear of the second flange portion 16 can be further suppressed. Therefore, the high-speed side shaft 12 can be supported more stably.

The embodiment may be modified as follows.
As shown in FIG. 6, when the second dimension L2 is increased in order to increase the second gap C2, the diameter of the second flange portion 16 is set so that the second end surface 72b and the second flange portion 16 face each other. The dimension in the direction may be increased.

The first dimension L1 and the second dimension L2 may be the same. In this case, as shown in FIG. 7, the dimension in the rotational axis direction Z from the boundary P1 between the first non-contact surface B1 and the contact surface A to the boundary P2 between the first non-contact surface B1 and the first end surface 72a is set to the first dimension. The third dimension L3, and the dimension in the rotation axis direction Z from the boundary P3 between the second non-contact surface B2 and the contact surface A to the boundary P4 between the second non-contact surface B2 and the second end surface 72b is defined as the fourth dimension L4. In this case, the fourth dimension L4 is made longer than the third dimension L3. In this case as well, the second gap C2 is larger than the first gap C1 and the oil O is easily supplied to the second flange portion 16.

The non-contact surfaces B1 and B2 do not have to be arcuate and may be tapered surfaces that linearly extend from the edge of the contact surface A to the end surfaces 72a and 72b.
The pump does not have to be built in the centrifugal compressor 10, and an external pump may be used.

The number of rollers 71 may be plural, and may be appropriately changed. For example, it may be four or five.
As the gearbox 60, a gearbox utilizing a wedge action may be used. In this case, at least one of the rollers 71 is a movable roller that moves by the rotation of the ring member 62.

The application of the centrifugal compressor 10 and the fluid to be compressed are arbitrary. For example, the centrifugal compressor 10 may be used in an air conditioner, and the fluid to be compressed may be a refrigerant. Further, the object to be mounted with the centrifugal compressor 10 is not limited to the vehicle, and is arbitrary.

The shapes of the first flange portion 15 and the second flange portion 16 may be changed appropriately. For example, a hexagonal ring or a square ring may be used.

A... Contact surface, B1... First non-contact surface, B2... Second non-contact surface, L1... First dimension, L2... Second dimension, 10... Centrifugal compressor, 11... Low speed side shaft, 12... High speed side shaft , 15... First flange part, 16... Second flange part, 50... Impeller housing, 71... Roller, 72a... First end face, 72b... Second end face.

Claims (1)

A ring member that rotates with the rotation of the low-speed side shaft and that has an annular portion;
A high-speed side shaft arranged inside the annular portion,
A plurality of rollers provided between the annular portion and the high speed side shaft, and contacting the annular portion and the high speed side shaft via oil;
An impeller that integrally rotates with the high-speed side shaft,
A gearbox housing that accommodates a part of the ring member, the roller, and the high-speed side shaft;
An impeller housing in which the impeller is housed,
The high-speed side shaft,
A first flange portion facing a first end surface, which is one of both end surfaces of the roller in the rotation axis direction,
In the rotational axis direction of the high-speed side shaft, than the first flange portion is provided away from the impeller, have if directed to different second end surface and the first end surface of said end faces, the plurality of rollers A second flange portion that is pressed against the second end surface ,
The outer peripheral surface of the roller is
A contact surface that comes into contact with a portion of the peripheral surface of the high-speed side shaft between the first flange portion and the second flange portion;
An annular first non-contact surface that is a portion of the outer peripheral surface of the roller from the edge of the contact surface to the first end surface and that surrounds the first end surface by being separated from the peripheral surface of the high speed side shaft. When,
An annular second non-contact surface that is a portion of the outer peripheral surface of the roller from the edge of the contact surface to the second end surface, and is separated from the peripheral surface of the high-speed side shaft to surround the second end surface. And,
Center position of the contact surface in the rotation axis direction of the roller, Ri said first flange portion closer der than the center position of the rollers,
A radial dimension of the roller from a boundary between the first non-contact surface and the contact surface to a boundary between the first non-contact surface and the first end surface is defined as a first dimension,
If the radial dimension of the roller from the boundary between the second non-contact surface and the contact surface to the boundary between the second non-contact surface and the second end surface is the second dimension,
A centrifugal compressor in which the second dimension is longer than the first dimension .