JP2017044190A - Impeller and turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impeller facilitating balance adjustment after assembling in the whole apparatus.SOLUTION: An impeller 50 is equipped with a generally truncated cone-shaped hub portion 51, whole blades 52, half blades 53, and projections 57. The hub portion 51 has an outer peripheral surface gradually increasing a diameter in a rotary axis direction. The whole blades 52 and the half blades 53 are formed so as to project out from the outer peripheral surface of the hub portion 51 to the outside in a diametrical direction, and pressure-feed a fluid flowing from a rotary axis ZC direction to the outside in the diametrical direction. Inter-blade spaces 58 sandwiched between the whole blades 52 and the half blades 53 are formed between the adjacent whole blades 52 and half blades 53. The projections 57 are projected out from the outer peripheral surface of the hub portion 51 in the inter-blade spaces 58, and extend in a flowing direction of the fluid flowing toward the outside in the diametrical direction in the inter-blade spaces 58.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an impeller and a turbocharger including the impeller.

  A turbocharger attached to an engine mounted on a vehicle has a rotating body that rotates using exhaust from the engine as a power source. By this rotation of the rotating body, air is forced into the combustion chamber of the engine.

  The rotating body of the turbocharger rotates at high speed. When mass imbalance exists in the rotating body, it causes vibration and noise of the rotating body. For this reason, conventionally, a technique for adjusting the balance by removing a part of the rotating body has been proposed (see, for example, Patent Documents 1 and 2).

JP 58-21118A Japanese Utility Model Publication No. 56-139802

  It is necessary to adjust the balance of the rotator alone, and it is also necessary to adjust the balance of the entire device after assembling the device including the rotator. In Patent Documents 1 and 2, it is disclosed that a protrusion for balance adjustment is provided on the back surface of the hub portion of the impeller. However, the protrusion on the back surface of the hub portion cannot be cut after the device is assembled. For this reason, it has been difficult to adjust the balance of the entire device after assembly.

  An object of the present invention is to provide an impeller that facilitates balance adjustment after assembly in the entire device including the impeller, and a turbocharger that facilitates balance adjustment after assembly.

  The impeller according to the present invention includes a substantially truncated cone-shaped hub portion and a plurality of wing portions. The hub portion has an outer peripheral surface whose diameter gradually increases along the rotation axis direction. The wing portion pumps the fluid flowing in from the rotation axis direction to the outside in the radial direction. The wing portion is formed to protrude radially outward from the outer peripheral surface of the hub portion. An inter-blade space sandwiched between the wings is formed between two adjacent wings. The impeller further includes a protrusion. The protrusion protrudes from the outer peripheral surface in the space between the blades. The protrusion extends along the flow direction of the fluid flowing in the space between the blades outward in the radial direction.

  Preferably, in the impeller, the root portion and the protrusion portion of the wing portion are curved in the same direction with respect to the radial direction. Of the two adjacent wings, the projection extends along the direction in which the root of one of the wings outside the curve of the projection extends.

  In the impeller, preferably, an end portion of the upstream protruding portion in the fluid flow direction forms an acute angle.

  Preferably, in the impeller, the hub portion has an outer peripheral edge portion. The downstream end of the protrusion in the fluid flow direction extends to the outer peripheral edge.

  Preferably, in the impeller, a notch part in which a part of the protrusion part is deleted is formed in the protrusion part.

  A turbocharger according to the present invention includes a turbine disposed in an exhaust passage, an impeller disposed in an intake passage, and a shaft connecting the turbine and the impeller. The impeller has a substantially truncated cone-shaped hub portion, a plurality of wing portions, and a projection portion. The hub portion has an outer peripheral surface whose diameter gradually increases along the rotation axis direction. The wing portion pumps the fluid flowing in from the rotation axis direction to the outside in the radial direction. The wing portion is formed to protrude radially outward from the outer peripheral surface of the hub portion. The protrusion part protrudes from the outer peripheral surface in the space between wings sandwiched between two adjacent wing parts. The protrusion extends along the flow direction of the fluid flowing in the space between the blades outward in the radial direction.

  According to the impeller of the present invention, it is possible to easily adjust the balance after assembly in the entire apparatus including the impeller.

It is a perspective view of the appearance of a turbo unit. It is sectional drawing along the rotating shaft of a turbocharger. It is a perspective view explaining the external appearance of an impeller. It is a top view explaining the external appearance of an impeller. FIG. 5 is a partial cross-sectional view of the impeller shown in FIGS. 3 and 4. It is a fragmentary sectional view which expands and shows the projection part of the 1st example. It is sectional drawing which shows the state by which the notch part was formed in the projection part of a 1st example. It is a fragmentary sectional view which expands and shows the projection part of the 2nd example. It is sectional drawing of a part of impeller which has a projection part of the 3rd example. It is a fragmentary sectional view which expands and shows the projection part of the 3rd example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  First, the overall structure of the turbocharger 1 will be described. In the present embodiment, a turbocharger 1 attached to an internal combustion engine mounted on a vehicle will be described as an example.

  FIG. 1 is a perspective view of the appearance of a turbo unit. The turbo unit is configured by connecting an intake discharge port 2 </ b> B of the inlet elbow 2 to the intake flow inlet 20 </ b> A of the turbocharger 1. The turbocharger 1 has a compressor constituted by an intake housing 20 and an impeller, and an exhaust housing 10.

  The inlet elbow 2 is formed in a substantially cylindrical shape, and has an intake air inlet 2A and an intake discharge port 2B. In order to accommodate the turbo unit in a limited mounting space in the engine room of the vehicle, the inlet elbow 2 is shaped to be curved in various directions. A streamline 2Z indicated by a dotted line in FIG. 1 indicates a streamline of intake air (air) passing through the curved inlet elbow 2.

  FIG. 2 is a cross-sectional view of the turbocharger 1 along the direction of the rotation axis ZC. The turbocharger 1 has three housings, an exhaust housing 10, an intake housing 20, and a bearing housing 30.

  A shaft 31 is provided in the bearing housing 30. The shaft 31 is supported by a bearing so as to be rotatable around the rotation axis ZC. A turbine 40 is provided in the exhaust housing 10. An impeller 50 is provided in the intake housing 20.

  The turbine 40 is fixed to the tip of the shaft 31 on the exhaust housing 10 side. The impeller 50 is formed with a through hole through which the shaft 31 passes. The impeller 50 is fixed with a nut 32 near the tip of the shaft 31 on the side of the intake housing 20. The turbine 40 and the impeller 50 are connected by a shaft 31. The turbine 40, the shaft 31, and the impeller 50 are integrally rotatable around the rotation axis ZC.

  Energy is recovered in the exhaust housing 10 by an exhaust inlet 10A (see FIG. 1) through which exhaust gas from the internal combustion engine flows, a scroll chamber 10S that guides the introduced exhaust gas to the turbine 40, and the turbine 40. An exhaust discharge port 10B that discharges exhaust is formed. In the exhaust housing 10, a variable nozzle 60 that adjusts the flow rate of exhaust gas flowing from the scroll chamber 10 </ b> S toward the turbine 40, and plates 61 and 62 that support the variable nozzle are provided.

  The intake housing 20 has an intake air inlet 20A through which intake air (air) taken in by the internal combustion engine flows, a scroll chamber 20C serving as a passage for air that flows into the intake housing 20 and is transferred (pressure-fed) by the impeller 50, In addition, an intake discharge port 20B (see FIG. 1) serving as an outlet for the transferred (pressure-feed) air is formed. A shroud member 21 and a scroll member 22 are provided in the intake housing 20. The shroud member 21 and the scroll member 22 form a scroll chamber 20C.

  The operation of the turbocharger 1 will be described. The exhaust gas discharged from the internal combustion engine flows into the turbocharger 1 from the exhaust inlet 10A in the process of flowing through the exhaust passage. Exhaust gas passes through a passage between adjacent variable nozzles 60 in the scroll chamber 10 </ b> S of the exhaust housing 10 and is blown to the turbine 40.

  The turbine 40 is rotationally driven by this exhaust gas blowing. The rotation of the turbine 40 is transmitted to the impeller 50 coaxial with the turbine 40 via the shaft 31. Thereby, the impeller 50 rotates integrally with the turbine 40. As the impeller 50 of the turbocharger 1 rotates, air is forced into the combustion chamber of the internal combustion engine (supercharged). In this way, the efficiency of filling the combustion chamber with air is increased. The impeller 50 is a member for supercharging the internal combustion engine using the rotational power of the turbine 40.

  Next, the shape of the impeller 50 of the present embodiment will be described. FIG. 3 is a perspective view for explaining the external appearance of the impeller 50. FIG. 4 is a plan view for explaining the external appearance of the impeller 50. FIG. 5 is a cross-sectional view of a part of the impeller 50 shown in FIGS. FIG. 4 is a plan view of the impeller 50 viewed from the direction along the rotation axis ZC. FIG. 5 shows a cross section of the impeller 50 along the cut surface including the rotation axis ZC.

  As shown in FIGS. 3, 4 and 5, the impeller 50 has a hub portion 51. The hub part 51 has a substantially truncated cone shape. The hub part 51 has the front-end | tip part 54, the outer periphery part 55, and the back surface 51b. The front end portion 54 is an end portion on the exhaust inflow side in the hub portion 51. The outer peripheral edge portion 55 is a portion having the largest outer diameter in the hub portion 51 and is a portion that discharges exhaust toward the radially outer side. The back surface 51b is an outer surface of the impeller 50 facing the bearing housing 30 in a state where the impeller 50 shown in FIG. 2 is assembled. The back surface 51b is an outer surface of the impeller 50 that does not form an air flow path.

  The hub portion 51 has an outer peripheral surface (hub surface) 56. The outer peripheral surface 56 is formed so that the diameter increases in a parabolic shape from the front end portion 54 toward the outer peripheral edge portion 55 along the rotation axis ZC direction.

  A plurality of wing parts are formed on the surface of the hub part 51. The wing part transfers (pressure feeds) the fluid flowing in from the tip part 54 side along the rotation axis ZC direction to the outer side in the radial direction, and guides it to the outer peripheral edge part 55.

  The wing part has a plurality of full wings (long wings) 52 and a plurality of half wings (short wings) 53 having different lengths in the direction of the rotation axis ZC. The full blades 52 and the half blades 53 are alternately provided on the outer peripheral surface 56 of the impeller 50 in the circumferential direction around the rotation axis ZC. In the present embodiment, six full blades 52 and six half blades 53 are provided alternately in the circumferential direction of the impeller 50.

  The entire blade 52 is formed to protrude radially outward from the outer peripheral surface 56 of the hub portion 51 from the vicinity of the tip portion 54 constituting the fluid inlet portion to the outer peripheral edge portion 55 constituting the fluid outlet portion. . The half blade 53 is formed to project radially outward from the outer peripheral surface 56 of the hub portion 51 from the midway position of the flow path formed between all adjacent blades 52, 52 to the outer peripheral edge portion 55. The half blade 53 is shorter than the full blade 52 in the fluid flow direction F (FIG. 5).

  3 and 4, the rotation direction of the impeller 50 is indicated by a broken line. The full wings 52 and the half wings 53 have curved shapes that are bent toward the downstream in the rotation direction of the impeller 50 as they approach the outer peripheral edge 55. All blades 52 and half blades 53 have a suction surface on the rear side in the rotational direction and a pressure surface on the front side in the rotational direction.

  An inter-blade space 58 is formed between the adjacent all blades 52 and the half blades 53. The inter-blade space 58 is sandwiched between the entire wing 52 and the half wing 53. Three sides of the inter-blade space 58 are surrounded by the suction surface of the entire blade 52, the pressure surface of the half blade 53, and the outer peripheral surface (hub surface) 56. Six inter-blade spaces 58 are formed on the rear side in the rotation direction with respect to the entire blade 52 and on the front side in the rotation direction with respect to the half blade 53.

  Projections 57 are formed in each of the six inter-blade spaces 58. The same number of protrusions 57 as the all wings 52 are provided. The protrusions 57 are provided in the same number as the half wings 53. The number of the protrusions 57 is a number other than 1 out of the divisor of the total number of the entire blades 52 and the half blades 53. In the present embodiment, since the total number of all the wings 52 and half wings 53 is 12, the number of the protrusions 57 may be 2, 3, 4, 6, or 12.

  The protruding portion 57 is formed to protrude radially outward from the outer peripheral surface 56 of the hub portion 51. The protrusion 57 is formed at an intermediate position in the fluid flow direction F of the inter-blade space 58 formed between the entire blade 52 and the half blade 53. The protrusion 57 extends along the fluid flow direction F. The fluid (air) flowing through the inter-blade space 58 flows radially outward toward the outer peripheral edge 55 of the impeller 50, as shown in FIG.

  FIG. 6 is an enlarged partial cross-sectional view showing the protrusion 57 of the first example. In FIG. 6, the protrusion 57, the root portion 52 b of the entire blade 52 (see also FIG. 3), and the root portion 53 b of the half blade 53 (see also FIG. 3), An enlarged plan view seen from the direction along the rotation axis ZC is shown. The entire blade 52 shown in FIG. 6 is a cross section cut leaving the root portion 52b, and the half blade 53 is a cross section cut leaving the root portion 53b.

  The protrusion 57 of the first example shown in FIG. 6 has a wing shape. The protrusion 57 has a leading edge 57L that is an upstream end in the fluid flow direction F and a trailing edge 57T that is a downstream end in the fluid flow direction F. The leading edge 57L constitutes an edge of the protrusion 57 on the inner side in the radial direction of the impeller 50. The trailing edge 57T constitutes an edge of the protrusion 57 on the outer side in the radial direction of the impeller 50.

  The protrusion 57 has side walls 57A and 57B. The side wall 57 </ b> A is a side surface of the protrusion 57 that faces the half wing 53. The side wall 57 </ b> B is a side surface of the protrusion 57 that faces the entire wing 52.

  The side wall 57A and the side wall 57B are joined to each other at the leading edge 57L, and are joined to each other at the trailing edge 57T. The leading edge 57L constitutes the upstream edge of the side walls 57A and 57B in the fluid flow direction F. The trailing edge 57T constitutes the downstream edge of the side walls 57A and 57B in the fluid flow direction F. In the leading edge 57L, the side wall 57A and the side wall 57B form an acute angle. In the vicinity of the trailing edge 57T, the side wall 57A and the side wall 57B have a cylindrical surface shape.

  A center line CL indicated by a one-dot chain line in FIG. 6 is a line connecting points at equal distances from the side wall 57A and the side wall 57B from the leading edge 57L to the trailing edge 57T.

  The inter-blade space 58 formed between the adjacent all wings 52 and the half wings 53 is partitioned by the protrusions 57. The protrusion 57 partitions the inter-blade space 58 into an inter-blade space 58 a between the protrusion 57 and the half blade 53 and an inter-blade space 58 b between the entire blade 52 and the protrusion 57. The inter-blade space 58 a is sandwiched between the protrusion 57 and the half wing 53. The inter-blade space 58 b is sandwiched between the protrusion 57 and the entire wing 52. When the fluid flowing between the full blades 52 and the half blades 53 reaches the leading edge 57L of the projection 57, the fluid flows separately into either the inter-blade space 58a or the inter-blade space 58b.

  Three sides of the inter-blade space 58a are surrounded by the side wall 57A of the projection 57, the pressure surface of the half blade 53, and the outer peripheral surface (hub surface) 56. Three sides of the inter-blade space 58b are surrounded by the side wall 57B of the protrusion 57, the suction surface of all the blades 52, and the outer peripheral surface (hub surface) 56.

  As shown in FIG. 6, the root portion 52 b of the entire blade 52, the root portion 53 b of the half blade 53, and the center line CL of the protrusion 57 are curved in the same direction with respect to the radial direction of the impeller 50. . More specifically, the base portions 52b and 53b and the center line CL of the protrusion 57 are curved so as to go to the rear side in the rotational direction as going outward in the radial direction. The impeller 50 shown in FIG. 6 has a clockwise direction as a rotation direction, and the base portions 52b and 53b and the center line CL of the projection 57 are curved so as to turn counterclockwise as they approach the outer peripheral edge portion 55 of the impeller 50. doing.

  The full wing 52 and the half wing 53 have different curvatures. In the vicinity of the outer peripheral edge 55 of the impeller 50, the half blade 53 has a larger curvature than the entire blade 52.

  The half wing 53 is arranged inside the curve of the protrusion 57. The entire wing 52 is disposed outside the curve of the protrusion 57. The center line CL of the protrusion 57 has a curvature equal to the root portion 52 b of the entire blade 52. The center line CL of the protrusion 57 has a curvature different from that of the root portion 53 b of the half wing 53. Of the adjacent full wings 52 and half wings 53, the protrusions 57 extend along the direction in which the root portions 52 b of the full wings 52 that are outside the curve of the protrusions 57 extend.

  The impeller 50 is formed by a cutting method (so-called cutting) from a base material or a manufacturing method by precision casting. When manufacturing the impeller 50 by cutting, the protruding portion 57 can be easily formed by forming an unmachined portion of the cutting into the shape of the protruding portion 57. When the impeller 50 is manufactured by casting, the protrusion 57 can be easily formed by preparing a mold including the protrusion 57.

  FIG. 7 is a cross-sectional view showing a state in which a notch 59 is formed in the protrusion 57 of the first example. As shown in FIG. 7, a part of the tip portion where the protruding portion 57 protrudes from the outer peripheral surface 56 of the hub portion 51 is notched to form a notched portion 59. Such a notch 59 can be easily formed by removing a part of the protrusion 57 from the front end 54 side of the hub 51 using a processing tool such as a ball end mill. In addition to processing using a tool, the notch 59 may be formed using any other processing means such as laser processing.

  In the embodiment shown in FIG. 7, the notch 59 having a shape in which a part of the tip of the protrusion 57 is notched is formed, but the shape of the notch 59 is not limited to this example. Either or both of the end portions (the leading edge 57L or the trailing edge 57T shown in FIG. 6) in the extending direction of the protrusion 57 may be cut out. The notch 59 may be formed so that the entire tip of the protrusion 57 is processed so that the height at which the protrusion 57 protrudes from the outer peripheral surface 56 is reduced as a whole. Processing to delete all of the protrusions 57 may be performed. Processing may be carried out until a recess is formed in the outer peripheral surface 56 of the hub portion 51 after the entire protruding portion 57 is deleted.

  FIG. 8 is an enlarged partial sectional view showing the protrusion 57 of the second example. The protrusion 57 is not limited to the wing shape described with reference to FIG. The protruding portion 57 may have any shape as long as the protruding portion 57 extends along the flow direction F of the fluid flowing in the inter-blade space 58 radially outward. More specifically, the length along the center line CL between the leading edge 57L and the trailing edge 57T is the maximum value of the dimension between the side wall 57A and the side wall 57B in the direction orthogonal to the fluid flow direction F. The protrusion 57 may be formed so as to be larger than that.

  The protrusions 57 may be formed so that the direction along the fluid flow direction F is the longitudinal direction and the direction orthogonal to the fluid flow direction F is the short direction (thickness direction). If the protrusion 57 is formed such that the length along the center line CL between the leading edge 57L and the trailing edge 57T is a long diameter, and the dimension between the side wall 57A and the side wall 57B is a short diameter. Good.

  For example, as shown in FIG. 8, the central portion of the side wall 57 </ b> A in the fluid flow direction F may protrude toward the half blade 53, and the central portion of the sidewall 57 </ b> B in the fluid flow direction F may protrude toward the entire blade 52. . In the projection 57 shown in FIG. 8, the side wall 57A and the side wall 57B form an acute angle at both the leading edge 57L and the trailing edge 57T. Such a protrusion 57 can be easily formed by cutting.

  FIG. 9 is a partial cross-sectional view of an impeller having a protrusion 57 of the third example. FIG. 10 is an enlarged partial sectional view showing the protrusion 57 of the third example. In the protrusion 57 of the third example, a trailing edge 57T that is an end on the downstream side in the fluid flow direction F extends to the outer peripheral edge 55 of the impeller 50. The protruding portion 57 of the third example is formed at a position farthest from the distal end portion 54 in the rotation axis ZC direction on the outer peripheral surface 56 of the hub portion 51.

  Although there are portions that partially overlap with the above description, the characteristic configurations of the present embodiment are listed below. As shown in FIGS. 3 to 5, the impeller 50 of the present embodiment includes a substantially frustoconical hub portion 51, and full wings 52 and half wings 53 constituting a plurality of wing portions. The hub portion 51 has an outer peripheral surface 56 whose diameter gradually increases along the rotation axis ZC direction. The full blade 52 and the half blade 53 pump the fluid flowing in from the direction of the rotation axis ZC outward in the radial direction. The full blades 52 and the half blades 53 are formed so as to protrude radially outward from the outer peripheral surface 56 of the hub portion 51. An inter-blade space 58 sandwiched between the full wings 52 and the half wings 53 is formed between the adjacent full wings 52 and the half wings. The impeller 50 further includes a protrusion 57. The protruding portion 57 protrudes from the outer peripheral surface 56 of the hub portion 51 in the inter-blade space 58.

  In a conventional configuration in which no protrusion is formed in the space between the blades of the impeller, the balance of the rotating body after the turbocharger is assembled is corrected by cutting and removing a part of the nut that fastens the impeller to the shaft. It is common. The unbalance in the entire rotating body cannot be completely corrected unless it is corrected on two different surfaces in the axial direction. Therefore, in addition to the nut, the outer peripheral surface (hub surface) of the impeller is cut and removed, and the balance correction is performed on two different surfaces in the axial direction. However, since the impeller is a member that rotates at a high speed, and the hub surface is a portion that forms a flow path, if the hub surface is cut largely, the strength of the impeller is reduced, and the cutting location becomes resistance to the flow of the fluid and the flow is reduced. There is a risk of impeller performance degradation due to inhibition. Therefore, it is necessary to correct the balance by removing small portions of the hub surface little by little, and it is necessary to repeat the trial rotation of the rotating body and the cutting of the hub surface over and over again. Was bad.

  In the present embodiment, a protruding portion 57 that protrudes from the outer peripheral surface (hub surface) 56 of the hub portion 51 is provided. For example, as shown in FIG. 7, the balance of the entire turbocharger 1 can be easily corrected by cutting and removing the protrusions 57 as necessary after the assembly of the turbocharger 1. By increasing the weight that can be cut and removed by the protruding portion 57, it is possible to correct the balance by cutting and removing one protruding portion 57, so there is no need to divide and cut into multiple points. Therefore, workability related to balance correction can be improved.

  As shown in FIGS. 6, 8, and 10, the protrusion 57 extends along the flow direction F of the fluid that flows radially outward in the inter-blade space 58. By forming the protrusions 57 in this way, the protrusions 57 existing on the outer peripheral surface (hub surface) 56 of the hub part 51 without being removed by cutting function as a splitter provided in the inter-blade space 58. To do. The protrusion 57 has a function of preventing a side slip of the fluid from the inter-blade space 58a to the inter-blade space 58b. Thereby, the force in the direction toward the radially outer side of the impeller 50 acts more strongly on the fluid. By forming the protrusion 57 in a shape that promotes the flow of the fluid without hindering the flow of the fluid, the performance of the impeller 50 provided with the protrusion 57 can be improved.

  As shown in FIGS. 6, 8, and 10, the root portion 52 b of the entire blade 52, the root portion 53 b of the half blade 53, and the protrusion 57 are curved in the same direction with respect to the radial direction of the impeller 50. Of the full wings 52 and the half wings 53, the full wings 52 exist outside the protrusions 57. A protruding portion 57 extends along the direction in which the root portion 52b of the entire blade 52 extends. By forming the protrusions 57 in this way, the protrusions 57 can be reliably formed so as to extend along the flow direction F of the fluid flowing radially outward in the inter-blade space 58.

  As shown in FIGS. 6, 8 and 10, the end of the upstream protrusion 57 in the fluid flow direction F forms an acute angle.

  Since the outer peripheral surface 56 of the hub portion 51 has a substantially conical shape, the distance between the entire blade 52 and the half blade 53 becomes larger as the distance from the rotation axis ZC increases. The distance between the full blade 52 and the half blade 53 becomes larger as the outer peripheral edge portion 55 of the hub portion 51 is approached. The distance between the full blade 52 and the half blade 53 becomes larger toward the downstream side in the fluid flow direction F. In the inter-blade space 58, the flow path width increases toward the downstream side in the fluid flow direction F, so that the thickness allowed for the protrusion 57 becomes larger.

  Therefore, by forming the protrusion 57 so that the leading edge 57L forms an acute angle, the protrusion 57 is surely extended so as to extend along the flow direction F of the fluid flowing radially outward in the inter-blade space 58. Can be formed. Moreover, the flow path resistance divided into the inter-blade space 58a and the inter-blade space 58b can be further reduced.

  As shown in FIGS. 3 and 4, the hub portion 51 has an outer peripheral edge portion 55. As shown in FIGS. 9 and 10, the downstream end of the protrusion 57 in the fluid flow direction F extends to the outer peripheral edge 55. By forming the protrusion 57 in this manner, the protrusion 57 is formed at a position further away from the nut 32 shown in FIG. 2 in the direction of the rotation axis ZC. Therefore, the turbocharger 1 is obtained by cutting and removing the protrusion 57. Overall balance correction becomes easier. Furthermore, the performance of the impeller 50 can be further improved by the protrusions 57 existing on the outer peripheral surface 56 of the hub portion 51 without being removed by cutting.

  As shown in FIG. 7, the protrusion 57 is formed with a notch 59 from which a part of the protrusion 57 is deleted. The notch 59 shows a shape after a part of the protrusion 57 is cut and removed for balance correction. Therefore, in the turbocharger 1 having the impeller 50 in which the notch 59 is formed, the unbalance in the entire turbocharger 1 is reliably reduced.

  As shown in FIG. 2, the turbocharger 1 of the present embodiment 50 includes a turbine 40 provided with an exhaust passage, an impeller 50 provided in an intake passage, and a shaft that connects the turbine 40 and the impeller 50. 31. As shown in FIGS. 3 to 5, the impeller 50 includes a substantially frustoconical hub portion 51, and all blades 52 and half blades 53 constituting a plurality of blade portions. The hub portion 51 has an outer peripheral surface 56 whose diameter gradually increases along the rotation axis ZC direction. The full blade 52 and the half blade 53 pump the fluid flowing in from the direction of the rotation axis ZC outward in the radial direction. The full blades 52 and the half blades 53 are formed so as to protrude radially outward from the outer peripheral surface 56 of the hub portion 51. An inter-blade space 58 sandwiched between the full wings 52 and the half wings 53 is formed between the adjacent full wings 52 and the half wings. The impeller 50 further has a protrusion 57. The protruding portion 57 protrudes from the outer peripheral surface 56 of the hub portion 51 in the inter-blade space 58. As shown in FIGS. 6, 8, and 10, the protrusion 57 extends along the flow direction F of the fluid that flows radially outward in the inter-blade space 58.

  In the turbocharger 1 using the impeller 50 having such a projection 57, the balance of the entire turbocharger 1 can be easily corrected by cutting and removing the projection 57 as necessary after assembly. By forming the protrusions 57 in a shape that promotes the flow of fluid, the performance of the turbocharger 1 including the impeller 50 provided with the protrusions 57 can be improved.

  The turbocharger described so far is not limited to a vehicle equipped with an internal combustion engine, and can be applied to various uses. Further, the impeller described so far is not limited to the turbocharger, and can be applied to various rotating machines.

  Although the embodiment of the present invention has been described as above, the embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Turbocharger, 10 Exhaust housing, 20 Intake housing, 30 Bearing housing, 31 Shaft, 32 Nut, 40 Turbine, 50 impeller, 51 Hub part, 51b Back surface, 52 Full blade, 52b, 53b Root part, 53 Half blade, 54 Tip, 55 Outer peripheral edge, 56 Outer peripheral surface, 57 Protrusion, 57A, 57B Side wall, 57L Leading edge, 57T Trailing edge, 58, 58a, 58b Interblade space, 59 Notch, CL centerline, F flow Direction, ZC axis of rotation.

Claims (6)

A substantially frustoconical hub portion having an outer peripheral surface whose diameter gradually increases along the rotation axis direction;
A plurality of wing parts formed to project radially outward from the outer peripheral surface of the hub part and pumping fluid flowing in from the rotational axis direction radially outward;
Between the two adjacent wings, a space between the wings sandwiched between the wings is formed,
The impeller further includes a protrusion that protrudes from the outer peripheral surface in the inter-blade space and extends along a flow direction of the fluid flowing radially outward in the inter-blade space. The base part of the wing part and the protrusion part are curved in the same direction with respect to the radial direction,
2. The impeller according to claim 1, wherein, of the two adjacent wing portions, the projection portion extends along a direction in which a root portion of one wing portion outside the curve of the projection portion extends.   3. The impeller according to claim 1, wherein an end of the protrusion on the upstream side in the fluid flow direction forms an acute angle. The hub portion has an outer peripheral edge portion,
The impeller according to any one of claims 1 to 3, wherein an end of the protruding portion on the downstream side in the fluid flow direction extends to the outer peripheral edge.   The impeller according to any one of claims 1 to 4, wherein a notch part from which a part of the protrusion part is deleted is formed in the protrusion part. A turbine disposed in the exhaust passage;
An impeller disposed in the intake passage;
A turbocharger comprising: a shaft connecting the turbine and the impeller;
The impeller is
A substantially frustoconical hub portion having an outer peripheral surface whose diameter gradually increases along the rotation axis direction;
A plurality of blade portions that are formed to project radially outward from the outer peripheral surface of the hub portion, and pump the fluid that has flowed in from the rotational axis direction radially outward;
A protrusion that protrudes from the outer peripheral surface in the space between the blades sandwiched between the two adjacent blades and extends along the flow direction of the fluid that flows radially outward in the space between the blades. , Turbocharger.

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