JP2018168829A - Centrifugal compressor - Google Patents

Abstract

To stably support a high-speed side shaft.SOLUTION: A centrifugal compressor includes a speed-increasing gear. The speed-increasing gear includes a ring member coupled to a low-speed side shaft. The speed-increasing gear includes a high-speed side shaft 12, and three rollers 71 provided between the ring member and the high-speed side shaft, and contacting both of the ring member and the high-speed side shaft 12. The roller 71 includes a contact face A, a first non-contact face B1, and a second non-contact face B2 on its outer peripheral face. A center position CP1 in a rotation shaft axial line direction Z of the contact face A is nearer a first end face 72a than a center position CP2 in a rotation axial line direction Z of the roller 71. Across the contact face A, the first non-contact face B1 is positioned on a first flange part 15 side, and the second non-contact face B2 is positioned on a second flange part 16 side.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a centrifugal compressor.

  As a centrifugal compressor provided with a gearbox, it is described in patent document 1, for example. The centrifugal compressor includes an impeller housing in which an impeller is accommodated, and a speed increaser housing in which a speed increasing mechanism is accommodated. 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 disposed inside the ring member, and the ring member and the high speed side shaft. A plurality of rollers in contact with both shafts are provided. In the high-speed side shaft, an impeller is integrated with a portion inserted into the impeller housing. Oil for lubrication is supplied to the speed increasing mechanism.

JP, 2006-194251, A

  By the way, when the high-speed side shaft is inclined, the impeller may come into contact with the inner surface of the impeller housing. For this reason, in a centrifugal compressor provided with a speed increaser, it is desired to stably support a 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 that solves the above problem is a ring member that rotates with the rotation of a low-speed side shaft and has an annular part, a high-speed side shaft that is arranged inside the annular part, and the annular part. A plurality of rollers provided between the high speed side shaft and in contact with the annular portion and the high speed side shaft via oil; an impeller that rotates integrally with the high speed side shaft; the ring member; the roller; A speed increaser housing in which a part of the high speed side shaft is accommodated, and an impeller housing in which the impeller is accommodated, wherein the high speed side shaft is one of both end surfaces of the roller in the rotation axis direction. A first flange portion facing the first end surface, which is a surface of the high-speed side shaft, and in a rotational axis direction of the high-speed side shaft, the first flange portion is located farther from the impeller than the first flange portion. And a second flange portion facing a second end surface different from the first end surface of the both end surfaces, and the outer peripheral surface of the roller is the first flange portion of the peripheral surface of the high-speed side shaft. A contact surface in contact with a portion between the second flange portion and a portion of the outer peripheral surface of the roller from an edge of the contact surface to the first end surface, and separated from the peripheral surface of the high-speed shaft. A first non-contact surface and a second non-contact surface that is a portion from the edge of the contact surface to the second end surface of the outer peripheral surface of the roller and is spaced from the peripheral surface of the high-speed side shaft. The center position of the contact surface in the rotation axis direction of the roller 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 clearance defined between the second non-contact surface and the peripheral surface of the high-speed shaft is made larger than the clearance defined between the first non-contact surface and the peripheral surface of the high-speed shaft. Can do. When the gap is large, the oil easily enters, and as a result, the oil is more easily supplied to the second flange portion 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. Thus, the second flange portion is more likely to generate heat and wear than the first flange portion. When the second flange portion wears and the gap with the second end surface becomes large, the high speed side shaft moves in the direction of the rotation axis, or the high speed side shaft tilts. By making it easy 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 or the high-speed side shaft from being inclined. it can. Therefore, the high speed side shaft can be stably supported by suppressing wear of the high speed side shaft.

  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 shaft can be reduced. In a traction drive type speed increaser in which a roller and a high speed side shaft are brought into contact 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 to the high speed side shaft from the outer peripheral surface of the roller. On the other hand, if the overall dimension in the rotation axis direction of the roller is shortened to increase the surface pressure and the contact area between the peripheral surface of the high speed side shaft and the outer peripheral surface of the roller is reduced, the high speed side shaft is inclined. The impeller and the inner surface of the impeller housing are likely to come into contact with each other, which is not preferable.

  While providing the first non-contact surface and the second non-contact surface, the outer peripheral surface of the roller and the peripheral surface of the high-speed side shaft can be obtained by shifting the position of the contact surface 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 securing a surface pressure for solidifying the oil.

  For 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, When 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, the area exposed to the gap can be increased in the second flange portion. 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 cross-sectional view taken along line 2-2 of FIG. The perspective view which shows the relationship between a roller and a high-speed side shaft. FIG. 4 is a sectional view taken along line 4-4 of FIG. 2 showing a part of the speed increasing mechanism. 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.

  Hereinafter, an embodiment of the centrifugal compressor will be described. The centrifugal compressor is mounted on a fuel cell vehicle (FCV) that runs using the 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 that rotates the low-speed side shaft 11, and a high-speed side shaft by increasing the rotation of the low-speed side shaft 11. 12 and an impeller 52 that compresses fluid (air in this embodiment) by rotation of the high-speed side shaft 12.

  The high-speed side shaft 12 includes a cylindrical shaft body 14, an annular first flange portion 15 projecting radially from the shaft body 14, and an annular second flange portion 16 projecting radially from the shaft body 14. With. The first flange portion 15 and the second flange portion 16 are spaced 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 projecting portion 18 that extends from the first flange portion 15 in the rotational axis direction opposite to the support portion 17. Is provided. The 2nd flange part 16 is provided in the edge part on the opposite side to the edge part by the side of the impeller 52 among the both ends of the rotation axis direction of the high speed side shaft 12. FIG. 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, metal, and more specifically, iron or an iron alloy.

  The centrifugal compressor 10 constitutes an outline of the centrifugal compressor 10, and houses both shafts 11 and 12, the electric motor 13, and a speed increasing mechanism 61 that constitutes a part of the speed increasing device 60. A housing 20 is provided. The housing 20 has, for example, a substantially cylindrical shape (in detail, a cylindrical shape) as a whole.

  The housing 20 includes a motor housing 21 in which the electric motor 13 is accommodated, a speed increaser housing 23 in which the speed increasing mechanism 61 is accommodated, and an impeller housing 50 in which a suction port 50a through which fluid is sucked is formed. The suction port 50 a is provided on one end surface 20 a of the housing 20 in the axial direction. The impeller housing 50, the speed increaser housing 23, and the motor housing 21 are arranged in this order in the axial direction of the housing 20 when 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 cylindrical shape (in detail, 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 on the opposite side to the one end surface 20a where the suction port 50a is located, of both end surfaces 20a and 20b in the axial direction of the housing 20. The speed-up gear housing 23 includes a cylindrical main body portion 25 having a bottom portion 24 (specifically, a cylindrical shape), and a closing portion 26 provided on the opposite side of 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 is in contact with the bottom 24 of the main body 25. A motor housing chamber S <b> 1 in which the electric motor 13 is housed is formed by the inner surface of the motor housing 21 and the bottom surface 24 a on the motor housing 21 side of the bottom 24 of the main body 25. The motor housing chamber S1 accommodates the low speed side shaft 11 in a state where the rotational axis direction of the low speed side shaft 11 and the axial direction of the housing 20 coincide.

  The low speed side shaft 11 is supported by the housing 20 in a rotatable state. The centrifugal compressor 10 includes a first bearing 31. The first bearing 31 is provided on the bottom 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 into the bottom portion 22 of the motor housing 21 through the first bearing 31.

  The bottom portion 24 of the main body portion 25 includes a through hole 27 that is formed to be slightly larger than the second end portion 11 b opposite to the first end portion 11 a of the low speed side shaft 11. The centrifugal compressor 10 includes a second bearing 32 and a seal member 33 in the through hole 27. The second end portion 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 portion 11 b of the low speed side shaft 11 is inserted into the through hole 27 of the main body portion 25, and a part of the low speed side shaft 11 is disposed in the speed increaser housing 23.
The electric motor 13 includes a rotor 41 fixed to the low-speed shaft 11 and a stator 42 that is disposed 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 part 26 has, for example, a disk shape having the same diameter as that of the gearbox housing 23. The speed-up gear housing 23 is assembled in a state in which the opening end of the main body 25 and the first plate surface 26a of both the plate surfaces 26a and 26b in the axial direction of the closing portion 26 abut each other. Thereby, the speed increasing device chamber S2 in which the speed increasing mechanism 61 is accommodated is formed by the first plate surface 26a of the closing portion 26 and the inner surface of the speed increasing device housing 23.

  The closing portion 26 constituting the speed increaser housing 23 includes an insertion hole 28 into which the high speed side shaft 12 constituting 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 increaser chamber S2. The 1st flange part 15, the 2nd flange part 16, and the support part 17 are arrange | positioned in the gear box S2. The centrifugal compressor 10 includes a seal member 34 that restricts the oil O in the speed increaser housing 23 from flowing into the impeller housing 50 between the inner surface of the insertion hole 28 and the high speed side shaft 12.

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

  The impeller housing 50 and the closing part 26 are the other end face 50c opposite to the one end face 50b in the axial direction of the impeller housing 50, and the second plate face 26b opposite to the first plate face 26a in the closing part 26. It is assembled in the state where they faced each other. Thereby, the impeller chamber S3 in which the impeller 52 is accommodated is formed by the inner surface of the comp through-hole 51 and the second plate surface 26b of the closing portion 26. That is, the comp through-hole 51 functions as a suction port 50a and functions as a partition for 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 increasing machine chamber S2 and the impeller chamber S3 serves as a partition wall that partitions the two.

  Here, the compressor through-hole 51 has a constant diameter from the suction port 50 a to the midway position in the axial direction, and has a substantially truncated cone shape that gradually increases in diameter from the midway position toward the closing portion 26. For this reason, 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 cylindrical shape with a diameter gradually reduced from the proximal end surface 52a toward the distal 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 allows the high speed side shaft 12 to be inserted 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. As the high speed side shaft 12 rotates, the impeller 52 rotates 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 channel 53 is continuous with the opening end of the imp through housing 51 on the second plate surface 26 b side of the comp through hole 51 and faces the second plate surface 26 b, and the second plate surface 26 b of the closing portion 26. It is the flow path divided by. The diffuser flow channel 53 is disposed radially outside the impeller chamber S3 in the high-speed side shaft 12, 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 has an annular shape that is disposed on the radially outer side of 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 through 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 speed increaser 60 of the present 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 increasing device 60 includes a ring member 62 connected to the second end portion 11 b of the low speed side shaft 11. The ring member 62 includes a disk-like base 63 connected to the second end portion 11 b of the low-speed shaft 11 and an annular annular portion 64 that stands up from the edge of the base 63. The inner diameter of the annular portion 64 is set longer than the diameter of the second end portion 11 b of the low speed side shaft 11.

  In the present embodiment, the ring member 62 is coupled to the low speed side shaft 11 so that the rotation axis direction of the base 63 (the rotation axis direction of the ring member 62) matches the rotation axis direction of the low speed side shaft 11. In addition, the rotation axis direction of the annular portion 64 also coincides with the rotation axis direction of the low speed side shaft 11. The ring member 62 rotates with the rotation of the low speed side shaft 11.

  A part of the high speed side shaft 12 is disposed 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 columnar first protrusion 73 protruding from the first end surface 72 a of the roller portion 72 in the rotation axis direction, and a second end surface 72 b of the roller portion 72 in the rotation axis direction. And a cylindrical second protrusion 74 that protrudes. The first end surface 72 a and the second end surface 72 b 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 rotation axis direction of the roller portion 72, the rotation axis direction of the first protrusion 73, and the rotation axis direction of the second protrusion 74 coincide with each other. Hereinafter, the rotation axis direction of the roller portion 72 is referred to as a rotation axis direction Z of the roller 71.

  The roller portion 72 includes a cylindrical contact portion 75, a first non-contact portion 76 whose diameter 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 small diameter. The diameter of the contact portion 75 (the length in the direction orthogonal to the rotation axis direction Z) is set longer than the diameter of the support portion 17 of the high speed side shaft 12. The first end surface 72 a can be said to be an end surface in the rotation axis direction Z of the first non-contact portion 76. It can be said that the second end surface 72 b is an end surface in the rotation axis direction Z of the second non-contact portion 77. The separation distance in the rotation axis direction Z between the first end surface 72a and the second end surface 72b 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 B 1 is the outer peripheral surface of the first non-contact portion 76, and the second non-contact surface B 2 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 round 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 round shape (arc shape) that protrudes outward in the radial direction.

  The dimension in the rotation axis direction Z of the first non-contact surface B1 is shorter than the dimension in the rotation axis direction Z of the second non-contact surface B2. Thereby, 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-contact 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 72 b that is the minimum diameter of the second non-contact portion 77 is shorter than the diameter of the first end surface 72 a that is the minimum diameter of the first non-contact portion 76. Each roller 71 is made of, for example, metal, and more specifically, is made of the same metal as that of the high speed side shaft 12, for example, iron or an iron alloy.

  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 in the circumferential direction of the high speed side shaft 12 at intervals.

  The roller 71 is disposed so that the roller portion 72 enters between the first flange portion 15 and the second flange portion 16. The roller portion 72 is disposed 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 in between. 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, the region surrounded by the peripheral surface of the support portion 17, the first non-contact surface B 1, and the first flange portion 15 is first. A gap C1 is defined. Since the second non-contact surface B2 is separated from the peripheral surface of the support portion 17, a second region is surrounded by the peripheral surface of the support portion 17, the second non-contact surface B2, and the second flange portion 16. A gap C2 is defined. The second gap C2 is larger than the first gap C1.

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

  Here, when the dimension of the contact surface A in the rotation axis direction Z is excessively shortened, the surface pressure is remarkably increased, and the high speed side shaft 12 is plastically deformed. More specifically, the high-speed shaft 12 whose outer peripheral surface is in contact with the outer peripheral surface of the roller 71 is likely to have a smaller contact area than the annular portion 64 whose inner peripheral surface is in contact with the outer peripheral surface of the roller 71, and the surface pressure is increased. It's easy to do. For this reason, if the dimension of the contact surface A in the rotation axis direction Z is excessively small, the surface pressure is excessively increased and plastic deformation is caused.

  Furthermore, the high speed side shaft 12 is not supported by a bearing (bearing) but is supported by the holding force of the roller 71, and the roller 71 has a minute dimensional difference due to manufacturing tolerances, etc. 10, there are many elements in which the axis of the high-speed shaft 12 is displaced. 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 rotatably supports each roller 71 in cooperation with the closing portion 26. The support member 80 is disposed in the annular portion 64. The support member 80 includes a disk-shaped support base 81 that is formed slightly smaller than the annular portion 64, and three columnar columnar members 82 that stand up from the support base 81. The support base 81 is disposed to face the closing portion 26 in the rotation axis direction Z. The three columnar members 82 stand from the opposing plate surface 81a facing the first plate surface 26a of the blocking portion 26 in the support base 81 toward the blocking portion 26, and are adjacent to the inner peripheral surface of the annular portion 64. The three spaces defined by the outer peripheral surfaces of the two roller portions 72 are filled up.

  As shown in FIGS. 1 and 2, the support member 80 includes screw holes 84 into which the bolts 83 can be screwed in each columnar member 82. The blocking portion 26 includes a screw hole 85 that communicates with the screw hole 84 so as to correspond to the screw hole 84. Each columnar member 82 is disposed at a position where the screw hole 84 and the screw hole 85 communicate with each other, and the front end surface of each columnar member 82 abuts against the first plate surface 26a. A bolt 83 is screwed so as to straddle 84 and the screw hole 85 to be fixed to the closing portion 26.

  The speed increaser 60 includes a first roller bearing 78 and a second roller bearing 79 that support the roller 71 in a rotatable state. The first roller bearing 78 and the second roller bearing 79 are bearings. The first roller bearing 78 is disposed in the closing portion 26. The second roller bearing 79 is disposed on the support base 81. The roller 71 is supported between the first roller bearing 78 and the second roller bearing 79 so as to be disposed between the closing portion 26 and the support base 81.

  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 three roller portions 72. At the ring-side contact point Pa, which is the contact point between the outer peripheral surface of the roller part 72 and the inner peripheral surface of the annular part 64, and at the contact point between the outer peripheral surface of the roller part 72 and the peripheral surface of the high-speed side shaft 12. A pressing load is applied to a certain shaft side contact portion Pb. Each contact point Pa, Pb extends in the rotation axis direction Z.

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

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

  The housing 20 includes a supply path 105 that becomes a part of the oil flow path 102 and a circulation path 106 that becomes a part of the oil flow path 102. The supply path 105 connects the accommodating portion 103 and the inside of the ring member 62. The circulation path 106 connects the speed increaser chamber S <b> 2 and the accommodating portion 103. The centrifugal compressor 10 is used in such a manner that a place where the circulation path 106 in the speed increaser housing 23 communicates is positioned downward in the vertical direction. Therefore, in the speed increaser housing 23, the oil O is stored by gravity at a place where the circulation path 106 communicates.

When the pump 101 is driven, the oil O flows in the order of the circulation path 106 → the accommodating portion 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 the present embodiment will be described.

  When the roller 71 rotates as the electric motor 13 is driven, a solidified oil O thin film (elastic fluid lubricating film (EHL)) 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 the oil O thin film. 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 solidified oil O thin film. Then, the rotational force of the roller 71 is transmitted to the high speed side shaft 12 through the solidified oil O thin film 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. The high speed side shaft 12 will rotate. 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 shorter diameter than the roller portion 72 rotates at a higher speed than the roller portion 72. From the above, the high speed side shaft 12 is rotated at a higher speed than the low speed side shaft 11 by the speed increaser 60.

  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 rotational force of the low-speed shaft 11 is increased by the solidified oil O thin film. 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, the contact area between the roller portion 72 and the peripheral surface of the high speed side shaft 12 is reduced by providing the non-contact surfaces B1 and B2. For this reason, the surface pressure is increased as compared with the case where the non-contact surfaces B1 and B2 are not provided. For this reason, 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 approaches the second flange portion 16 side. Then, when the high speed side shaft 12 is tilted, the amount of movement of the protrusion 18 increases, and the impeller 52 is likely to hit 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 in the rotation axis direction Z of the roller portion 72, so that the surface pressure is increased. In addition, the contact of the impeller 52 due to the inclination of the high speed side shaft 12 can also be suppressed.

  As shown in FIG. 5, in the roller 71 having the first non-contact surface B <b> 1 and the second non-contact surface B <b> 2, the center position CP <b> 11 in the rotation axis direction Z of the contact surface A and the rotation axis direction Z of the roller 71. 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 gap 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 C2 can be made larger than the first gap C1. As a result, the oil O enters the second gap C <b> 2 more easily than the first gap C <b> 1, and the amount of oil O supplied to the second flange portion 16 compared to the oil O supplied to the first flange portion 15. Will be more.

  Here, in the centrifugal compressor 10, the rear region S <b> 4 is defined between the base end surface 52 a of the impeller 52 and the closed portion 26 because of the need to prevent contact between the base end surface 52 a of the impeller 52 and the closed portion 26. Is 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 by the compressed fluid, and a thrust force in a direction from the speed increasing machine chamber S2 toward 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 72 b of each roller portion 72, so that the second flange portion 16 is more likely to generate heat and wear than the first flange portion 15. By making it easy to supply the oil O to the second flange portion 16, wear of the second flange portion 16 is suppressed.

  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, heat generated at the shaft-side contact portion Pb is not easily transmitted to the second flange portion 16. As a result, it is possible to suppress heat from being transmitted 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. Thus, the second gap C2 is larger than the first gap C1, and the oil O is easily supplied to the second flange part 16 that generates heat more easily than the first flange part 15. For this reason, the 2nd flange part 16 is hard to wear out, and a clearance gap does not arise easily between the 2nd flange part 16 and the 2nd end surface 72b. Thereby, it is possible to prevent the high speed side shaft 12 from moving in the rotation axis direction or the high speed side shaft 12 from being inclined 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 to the second flange portion 16. For this reason, the heat generated at the shaft-side contact portion Pb is hardly transmitted to the second flange portion 16, and 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 in the rotation axis direction Z of the roller portion 72. For this reason, the impeller 52 is prevented from coming into contact with the inner surface of the impeller housing 50 because the overall dimension of the roller portion 72 in the rotation axis direction Z is shortened.

  (4) In the centrifugal compressor 10 provided with the speed increaser 60, there are many elements that cause the shaft of the high speed side shaft 12 to shake. Since the dimension in the rotation axis direction Z of the contact surface A is not excessively shortened, the high speed side shaft 12 can be stably supported.

  (5) The second dimension L2 is longer than the first dimension L1. Thereby, in the 2nd flange part 16, the area exposed to the 2nd clearance gap C2 can be enlarged. The oil O can easily come into contact with the second flange portion 16, and wear of the second flange portion 16 can be further suppressed. For this reason, the high speed side shaft 12 can be supported more stably.

In addition, you may change embodiment 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 face 72b and the second flange portion 16 face each other. The direction dimension 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 rotation 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 the first dimension. 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. Also in this case, the second gap C <b> 2 is larger than the first gap C <b> 1, 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 arc-shaped, and may be tapered surfaces extending linearly from the edge of the contact surface A to the end surfaces 72a and 72b.
The pump may not be built in the centrifugal compressor 10, and an external pump may be used.

-The number of rollers 71 should just be two or more, and may change suitably. For example, it may be four or five.
As the speed increaser 60, a gear using 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 object of the centrifugal compressor 10 and the fluid of compression object 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. Moreover, the mounting object of 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 as appropriate. 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 ... 1st flange part, 16 ... 2nd flange part, 50 ... Impeller housing, 71 ... Roller, 72a ... 1st end surface, 72b ... 2nd end surface.

Claims (2)

A ring member that rotates with the rotation of the low-speed side shaft and has an annular portion;
A high-speed shaft disposed inside the annular portion;
A plurality of rollers provided between the annular portion and the high speed side shaft, and in contact with the annular portion and the high speed side shaft via oil;
An impeller that rotates integrally with the high-speed side shaft;
A gearbox housing in which a part of the ring member, the roller, and the high-speed side shaft is housed;
An impeller housing in which the impeller is accommodated,
The high speed side shaft is
A first flange portion facing a first end surface which is one of both end surfaces in the rotation axis direction of the roller;
A second flange portion that is provided farther from the impeller than the first flange portion in the rotational axis direction of the high-speed side shaft and faces a second end surface different from the first end surface of the both end surfaces; ,
The outer peripheral surface of the roller is
Of the peripheral surface of the high-speed side shaft, a contact surface that contacts a portion between the first flange portion and the second flange portion;
A portion of the outer peripheral surface of the roller from the edge of the contact surface to the first end surface, a first non-contact surface spaced from the peripheral surface of the high-speed shaft;
The outer peripheral surface of the roller is a portion from the edge of the contact surface to the second end surface, and is partitioned into a second non-contact surface spaced from the peripheral surface of the high speed side shaft,
The centrifugal compressor is such that a center position of the contact surface in a rotation axis direction of the roller is closer to the first flange portion than a center position of the roller. The radial dimension of the roller from the boundary between the first non-contact surface and the contact surface to the boundary between the first non-contact surface and the first end surface is a first dimension,
When 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 a second dimension,
The centrifugal compressor according to claim 1, wherein the second dimension is longer than the first dimension.