Variable displacement supercharger

Abstract

A variable displacement supercharger is provided with: a turbine housing that accommodates a turbine wheel; a variable nozzle unit having a nozzle vane disposed in a nozzle flow path provided around the turbine wheel in the turbine housing, and a drive mechanism unit for driving the nozzle vane; a belleville spring that biases the variable nozzle unit in the axial direction and presses the variable nozzle unit against one portion of the turbine housing; and an engagement part that engages the variable nozzle unit with the turbine housing so as to restrict the displacement of the variable nozzle unit in the circumferential direction, the engagement part being located in a region further radially outward than the range of movement of the nozzle vane.

Description

Technical Field

[0001] The present disclosure relates to a variable capacity supercharger. Background Art

[0002] A variable capacity supercharger described in Patent Document 1 is known. This supercharger includes a variable nozzle unit for adjusting the opening of the turbine nozzle flow path. Disc springs are interposed between the variable nozzle unit and the bearing housing. These disc springs bias the variable nozzle unit against the turbine housing, maintaining axial positioning.

[0003] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-68153

[0004] In a supercharger equipped with a variable nozzle unit, in order to position the variable nozzle unit within a plane perpendicular to the axial direction, for example, a pin extending in the axial direction can be pressed into the bearing housing, with the pin being loosely fitted into a pin hole formed in the variable nozzle unit. However, during operation of the supercharger, the disc spring load decreases due to thermal deformation or a decrease in Young's modulus. As a result, the friction between the variable nozzle unit and the turbine housing decreases, potentially causing circumferential displacement of the variable nozzle unit corresponding to the amount of play between the pin and the pin hole. Furthermore, if the variable nozzle unit is circumferentially displaced, the gas flow rate will change. Summary of the Invention

[0005] Therefore, the present disclosure describes a variable geometry turbocharger that suppresses changes in the flow rate of gas during operation.

[0006] The gist of a variable geometry supercharger according to one embodiment of the present disclosure is as follows.

[0007] [1] A variable capacity supercharger comprising:

[0008] a turbine housing housing a turbine impeller;

[0009] a variable nozzle unit having a nozzle vane disposed in a nozzle flow path provided around the turbine impeller in the turbine housing and having a drive mechanism for driving the nozzle vane;

[0010] a force applying portion that applies force to the variable nozzle unit along the rotation axis direction of the turbine impeller and presses the variable nozzle unit against a portion of the turbine housing; and

[0011] an engaging portion for engaging the variable nozzle unit with a predetermined portion so as to restrict displacement of the variable nozzle unit in the rotational circumferential direction of the turbine impeller,

[0012] The engagement portion is located in a region radially outward of a movable range of the nozzle vanes in the radial direction of rotation of the turbine impeller.

[0013] According to the variable geometry turbocharger of the present disclosure, it is possible to suppress changes in the flow rate of gas during operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional view showing the variable geometry supercharger according to the present embodiment.

[0015] Figure 2 It is an exploded perspective view showing the variable nozzle unit and the like.

[0016] Figure 3 This is a plan view of the variable nozzle unit viewed in the axial direction from the bearing housing side.

[0017] Figure 4 This is an enlarged cross-sectional view showing the vicinity of a variable nozzle unit of a variable geometry supercharger.

[0018] Figure 5 This is a diagram showing the nozzle ring and nozzle blades as viewed in the axial direction from the turbine side.

[0019] Figure 6 (a) is a perspective view of a nozzle ring to which the engaging portion of the first embodiment is applied, (b) is an enlarged cross-sectional view of the engaging portion, and (c) is a view of the engaging portion as viewed from the direction of arrow VIc.

[0020] Figure 7 (a) is a perspective view of a nozzle ring to which an engaging portion according to the second embodiment is applied, (b) is an enlarged sectional view of the engaging portion, and (c) is a view of the engaging portion as viewed from the direction of arrow VIIc.

[0021] Figure 8 (a) is a perspective view of a nozzle ring to which an engaging portion according to a third embodiment is applied, (b) is an enlarged cross-sectional view of the engaging portion, and (c) is a view of the engaging portion as viewed from the direction of arrow VIIIc.

[0022] Figure 9 (a) is a perspective view of a nozzle ring to which an engaging portion according to a fourth embodiment is applied, (b) is an enlarged sectional view of the engaging portion, and (c) is a view of the engaging portion as viewed from the direction of arrow IXc.

[0023] Figure 10 (a) is a perspective view of a nozzle ring to which an engaging portion according to a fifth embodiment is applied, (b) is an enlarged cross-sectional view of the engaging portion, and (c) is a view of the engaging portion as viewed from the direction of arrow Xc.

[0024] Figure 11This is a cross-sectional view showing a structure for restricting circumferential displacement of a variable nozzle unit in a conventional supercharger. DETAILED DESCRIPTION

[0025] The gist of a variable geometry supercharger according to one embodiment of the present disclosure is as follows.

[0026] [1] A variable capacity supercharger comprising:

[0027] a turbine housing housing a turbine impeller;

[0028] a variable nozzle unit having a nozzle vane disposed in a nozzle flow path provided around the turbine impeller in the turbine housing and having a drive mechanism for driving the nozzle vane;

[0029] a force applying portion that applies force to the variable nozzle unit along the rotation axis direction of the turbine impeller and presses the variable nozzle unit against a portion of the turbine housing; and

[0030] an engaging portion for engaging the variable nozzle unit with a predetermined portion so as to restrict displacement of the variable nozzle unit in the rotational circumferential direction of the turbine impeller,

[0031] The engagement portion is located in a region radially outward of a movable range of the nozzle vanes in the radial direction of rotation of the turbine impeller.

[0032] [2] The variable geometry supercharger according to [1], wherein:

[0033] The variable nozzle unit has a flange, which is arranged to protrude most radially outward in the variable nozzle unit.

[0034] The flange is pressed against the flange receiving portion of the turbine housing along the rotation axis direction by the biasing force of the biasing portion.

[0035] In the engagement portion, a portion of the flange is directly or indirectly engaged with the predetermined location.

[0036] [3] The variable capacity supercharger according to [2], wherein:

[0037] The engaging portion has:

[0038] a groove formed so as to be cut from the outermost edge surface of the flange toward the inner peripheral side; and

[0039] A pin extends from the turbine housing and is inserted into the slot.

[0040] [4] The variable capacity supercharger according to [2] or [3], wherein:

[0041] The engaging portion has:

[0042] a pin extending from one side of the flange or the turbine housing; and

[0043] A pin hole is provided on the other of the flange and the turbine housing and is used to insert the pin.

[0044] [5] The variable geometry supercharger according to any one of [2] to [3], wherein:

[0045] The engaging portion has:

[0046] a protrusion provided on one side of the flange or the flange receiving portion; and

[0047] The recessed portion is provided on the other side of the flange or the flange receiving portion and is used for the protrusion to be embedded.

[0048] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Figure 1 This is a cross-sectional view of the variable geometry supercharger 1 taken along a section including the rotation axis H. The variable geometry supercharger 1 is applied to internal combustion engines of ships and vehicles, for example.

[0049] like Figure 1 As shown, the supercharger 1 includes a turbine 2 and a compressor 3. The turbine 2 includes a turbine housing 4 and a turbine wheel 6 housed in the turbine housing 4. The turbine housing 4 has a scroll flow path 16 extending circumferentially around the turbine wheel 6. The compressor 3 includes a compressor housing 5 and a compressor wheel 7 housed in the compressor housing 5. The compressor housing 5 has a scroll flow path 17 extending circumferentially around the compressor wheel 7.

[0050] The turbine impeller 6 is provided at one end of a rotating shaft 14, and the compressor impeller 7 is provided at the other end of the rotating shaft 14. A bearing housing 13 is provided between the turbine housing 4 and the compressor housing 5. The rotating shaft 14 is rotatably supported by the bearing housing 13 via bearings 15. The rotating shaft 14, the turbine impeller 6, and the compressor impeller 7 rotate around the rotation axis H as a single rotating body.

[0051] The turbine housing 4 is provided with an exhaust gas inlet 8 and an exhaust gas outlet 10. Exhaust gas from an internal combustion engine (not shown) flows into the turbine housing 4 through the exhaust gas inlet 8, flows through the vortex flow path 16 into the turbine impeller 6, and rotates the turbine impeller 6. The exhaust gas then flows out of the turbine housing 4 through the exhaust gas outlet 10.

[0052] The compressor housing 5 is provided with an intake port 9 and an exhaust port 11. As described above, when the turbine impeller 6 rotates, the compressor impeller 7 rotates via the rotating shaft 14. The rotating compressor impeller 7 draws in external air through the intake port 9. This air is compressed by the compressor impeller 7 and the vortex flow path 17 and discharged from the exhaust port 11. The compressed air discharged from the exhaust port 11 is supplied to the internal combustion engine described above.

[0053] The turbine 2 of the supercharger 1 will be further described. In the following description, the terms "axial", "radial", and "circumferential" refer to the direction of the rotation axis of the turbine impeller 6 (the direction of the rotation axis H), the radial direction of rotation, and the circumferential direction of rotation, respectively. In addition, when referring to "upstream" and "downstream", etc., they refer to the upstream and downstream of the exhaust gas in the turbine 2. In addition, in the direction of the rotation axis H, the turbine 2 side of the supercharger 1 (in the direction of the rotation axis H) is sometimes referred to as Figure 1 The left side in the middle) is referred to as the "turbine side", and the compressor 3 side (in Figure 1 The right side (in the middle) is referred to as the "compressor side".

[0054] The turbine 2 of the supercharger 1 is provided with a nozzle flow path 19. This nozzle flow path 19 is arranged around the turbine impeller 6 and connects the vortex flow path 16 to the turbine impeller 6. A plurality of movable nozzle vanes 21 are provided in the nozzle flow path 19. The plurality of nozzle vanes 21 are arranged at approximately equal intervals on a circumference centered on the rotation axis H. Each nozzle vane 21 rotates synchronously about an axis NX parallel to the rotation axis H. As the plurality of nozzle vanes 21 rotate as described above, the gaps between adjacent nozzle vanes 21 expand and contract, thereby adjusting the opening of the nozzle flow path 19.

[0055] To drive the nozzle vanes 21 as described above, the turbine 2 includes a variable nozzle unit 20. The variable nozzle unit 20 is embedded inside the turbine casing 4. The variable nozzle unit 20 includes the aforementioned plurality of nozzle vanes 21 and two nozzle rings 23 and 27 axially sandwiching the nozzle vanes 21. The two nozzle rings 23 and 27 are arranged axially, with the nozzle ring 23 positioned closer to the compressor than the nozzle ring 27. The nozzle rings 23 and 27 each have an annular shape centered on the rotation axis H and are arranged to circumferentially surround the turbine impeller 6. The region axially sandwiched between the two nozzle rings 23 and 27 constitutes the aforementioned nozzle flow path 19. The nozzle rings 23 and 27 are axially connected to each other via a plurality of connecting pins 29, which are manufactured with high precision to ensure the axial dimensional accuracy of the nozzle flow path 19.

[0056] The variable nozzle unit 20 also includes a drive mechanism 25 for driving the nozzle vanes 21. The drive mechanism 25 is housed in a space between the nozzle ring 23 and the bearing housing 13, and transmits a drive force from an external actuator (not shown) to the nozzle vanes 21.

[0057] Reference Figure 2 and Figure 3 The drive mechanism 25 of the variable nozzle unit 20 will be described in more detail. Figure 2 It is an exploded perspective view showing the variable nozzle unit 20 , a heat shield plate 41 , and a disc spring 43 , which will be described later. Figure 3 This is a top view of the variable nozzle unit 20 as viewed axially from the bearing housing 13. The nozzle ring 23 is provided with bearing holes 31 extending axially therethrough. The rotation shaft 21a of each nozzle vane 21 is rotatably inserted through each bearing hole 31. While the nozzle vanes 21 are arranged at equal intervals around the circumference in the illustrated example, this arrangement is not essential.

[0058] The drive mechanism 25 includes a drive ring 33, a nozzle link plate 35, and a drive link plate 37. The drive ring 33 is annular and extends along a circumference centered on the rotation axis H. It is arranged along the compressor-side surface of the nozzle ring 23. The drive ring 33 is rotatable relative to the nozzle ring 23 about the rotation axis H. Engaging portions 33a for engaging with each nozzle link plate 35 are provided on the drive ring 33 at predetermined intervals in the circumferential direction.

[0059] The number of nozzle link plates 35 is the same as the number of nozzle vanes 21. Each nozzle link plate 35 is attached to the end of the rotating shaft 21a of the nozzle vane 21 and extends radially outward from this end. More specifically, each rotating shaft 21a of the nozzle vane 21 is inserted into the bearing hole 31, and each end of the rotating shaft 21a protrudes from the nozzle ring 23 toward the compressor. The inner circumferential end of each nozzle link plate 35 is attached to the end of the protruding rotating shaft 21a. The outer circumferential end of each nozzle link plate 35 engages with the engaging portion 33a of the drive ring 33.

[0060] In addition, the drive ring 33 is provided with an input side engaging portion 33b. The input side engaging portion 33b is located between a set of engaging portions 33a. The outer peripheral end of the drive link plate 37 is engaged with the input side engaging portion 33b, and the inner peripheral end of the drive link plate 37 is engaged with the drive shaft 39 ( Figure 3 )connect.

[0061] When an external actuator rotates the drive link plate 37 about an axis parallel to the rotation axis H via the drive shaft 39, the outer peripheral end of the drive link plate 37 presses the input-side engaging portion 33b in the circumferential direction. This causes the drive ring 33 to rotate about the rotation axis H, and the engaging portions 33a of the drive ring 33 press the outer peripheral end of each nozzle link plate 35 in the circumferential direction. Consequently, each nozzle link plate 35 rotates about the axis NX, and the nozzle vanes 21 fixed to each nozzle link plate 35 rotate about the axis NX.

[0062] Next, the structure for positioning the variable nozzle unit 20 described above in the turbine housing 4 will be described. Figure 1 and Figure 2 As shown, a heat shield 41 is provided between the turbine wheel 6 and the bearing housing 13. The heat shield 41 shields the high-temperature turbine housing 4 from radiant heat, thereby suppressing temperature increases in the bearing housing 13. The heat shield 41 is annular and circumferentially surrounds the rotating shaft 14. The heat shield 41 is inserted into the central opening of the nozzle ring 23 from the bearing housing 13 side.

[0063] A disc spring 43 is sandwiched between the heat shield plate 41 and the bearing housing 13. The rotating shaft 14 is inserted through a central hole in the disc spring 43, and the disc spring 43 is arranged along a conical surface with the rotation axis H as its conical axis. One axial end of the disc spring 43 contacts the bearing housing 13, while the other end contacts the heat shield plate 41. The disc spring 43 generates a repulsive force that increases the distance between the bearing housing 13 and the heat shield plate 41 in the axial direction. This disc spring 43 axially biases the variable nozzle unit 20 and the heat shield plate 41 toward the turbine housing 4.

[0064] Figure 4 It will Figure 1 The figure shows an enlarged cross-sectional view of the area surrounding the variable nozzle unit 20. The nozzle ring 23 has a flange 45 that extends outward. The turbine housing 4 has a ridge 47 that receives the flange 45. The ridge 47 extends inward from the inner wall of the turbine housing 4 and annularly along a circle centered on the rotation axis H. The inner diameter of the ridge 47 is smaller than the outer diameter of the flange 45, and the flange 45 abuts against the ridge 47 from the bearing housing 13 side.

[0065] With this structure, the variable nozzle unit 20 is biased toward the turbine by the disc spring 43. This biasing force presses the flange 45 of the nozzle ring 23 against the ridge 47. Furthermore, by pressing the flange 45 against the ridge 47, the variable nozzle unit 20 is positioned and fixed in the axial direction. Furthermore, the friction between the flange 45 and the ridge 47 also secures the variable nozzle unit 20 with a certain degree of force in the in-plane direction perpendicular to the axial direction. However, if a thermal expansion difference occurs between the variable nozzle unit 20 and the turbine housing 4, the flange 45 and the ridge 47 slide together, absorbing this thermal expansion difference.

[0066] Next, the positioning of the variable nozzle unit 20 in the circumferential and radial directions will be described. As described above, the variable nozzle unit 20 is fixed with a certain degree of fixing force in the in-plane direction perpendicular to the axial direction by utilizing the friction between the flange 45 and the ridge portion 47 (flange receiving portion). Here, in the past, as a structure for further limiting the circumferential displacement of the variable nozzle unit 20, for example, Figure 11The structure shown in FIG. In this structure, a pin 101 is provided, extending axially from the bearing housing 13 toward the turbine side. The pin 101 is press-fitted into the bearing housing 13, positioned radially offset from the rotation axis H. The nozzle ring 23 of the variable nozzle unit 20 is provided with a pin hole 103 for inserting the pin 101. By inserting the pin 101 into the pin hole 103 with a clearance fit, the variable nozzle unit 20 is positioned in a plane perpendicular to the axial direction.

[0067] However, during operation of the supercharger 1, the disc spring load applied by the disc spring 43 decreases due to thermal deformation or a decrease in the Young's modulus of the disc spring 43 (the force-applying portion). This reduces the friction between the flange 45 and the ridge 47, potentially causing circumferential displacement (rotational displacement about the rotation axis H) of the variable nozzle unit 20 by the amount of play between the pin 101 and the pinhole 103. Circumferential displacement of the variable nozzle unit 20 can cause changes in the exhaust gas flow rate, particularly when the nozzle flow path 19 is closed. Therefore, the supercharger 1 includes the following structure to suppress circumferential displacement of the variable nozzle unit 20 during operation.

[0068] In the supercharger 1, the variable nozzle unit 20 engages with the turbine housing 4 at a predetermined engagement portion, thereby restricting circumferential displacement of the variable nozzle unit 20. The structure of the engagement portion will be described in detail later. Figure 5 This figure shows the nozzle ring 23 and nozzle vanes 21 viewed axially from the turbine side. In the supercharger 1, the aforementioned engaging portion is located in an area radially outward from the circle C1 shown in the figure. Circle C1 refers to the circle circumscribing each nozzle vane 21 when the nozzle flow path 19 is at its maximum opening. Therefore, the area radially outward from circle C1 refers to the area radially outward from the movable range of the nozzle vanes 21. As is geometrically clear, the further radially outward the engagement portion between the variable nozzle unit 20 and the turbine housing 4 is positioned, the smaller the circumferential displacement of the variable nozzle unit 20 caused by circumferential play of the engagement portion. Therefore, in the supercharger 1, by providing the engaging portion as far outward as possible, such as in the area radially outward from circle C1, circumferential displacement of the variable nozzle unit 20 during operation can be suppressed, thereby suppressing fluctuations in the flow rate of exhaust gas from the nozzle flow path 19.

[0069] A specific embodiment for setting the engagement portion between the variable nozzle unit 20 and the turbine housing 4 as described above in an area radially outward from the circle C1 will be described. The engagement portions 50A, 50B, 50C, 50D, and 50E of each embodiment described below are all set at the position of the flange 45 of the nozzle ring 23 of the variable nozzle unit 20. The flange 45 of the nozzle ring 23 extends with a constant width in the circumferential direction over the entire circumference and is located in an area radially outward from the circle C1. In addition, as Figure 4As shown in FIG. 1 , the flange 45 is the portion of the variable nozzle unit 20 that extends most radially outward. Figures 1 to 5 In the figure, the engaging portions 50A, 50B, 50C, 50D, and 50E are omitted.

[0070] (First embodiment)

[0071] Figure 6 (a) is a perspective view of the nozzle ring 23 to which the engaging portion 50A is applied. Figure 6 (b) is a cross-sectional view showing an enlarged view of the engaging portion 50A. Figure 6 (c) is a view of the engaging portion 50A viewed from the direction of arrow VIc. Figure 6 As shown in (a), the engaging portion 50A has a U-shaped groove 51 formed in the flange 45 of the nozzle ring 23. The U-shaped groove 51 is formed so as to be cut into the entire thickness of the flange 45 from the outermost edge surface 45a of the flange 45 toward the inner peripheral side with the groove depth direction as the radial direction. Figure 6 (b) and Figure 6 As shown in (c), the engaging portion 50A includes a pin 53 provided on the ridge 47 and inserted into the U-shaped groove 51. The pin 53 is pressed into the flange receiving surface 47b of the ridge 47 and extends axially from the flange receiving surface 47b toward the compressor. The pin 53 can be a solid pin made of a solid member or a coil pin. The pin 53 has a circular cross-section with a diameter approximately equal to the width of the U-shaped groove 51 and is a loose fit within the U-shaped groove 51.

[0072] The engaging portion 50A restricts circumferential displacement of the variable nozzle unit 20. The variable nozzle unit 20 may displace circumferentially by the amount of circumferential play caused by the U-shaped groove 51 and the pin 53. However, because the engaging portion 50A is located at the outermost portion of the variable nozzle unit 20, i.e., at the location of the flange 45, the circumferential displacement of the variable nozzle unit 20 caused by circumferential play is minimized, as described above. Therefore, the supercharger 1 equipped with the engaging portion 50A can suppress circumferential displacement of the variable nozzle unit 20 during operation, thereby suppressing fluctuations in the flow rate of the exhaust gas from the nozzle flow path 19.

[0073] In addition, in the existing Figure 11 In the structure, the pin 101 is provided in the bearing housing 13, which has a lower temperature than the nozzle ring 23 during operation. Therefore, there is a temperature difference between the pin 101 and the nozzle ring 23, and due to the difference in thermal expansion between the pin 101 and the pin hole 103, the play between the two tends to increase. In contrast, in the engaging portion 50A ( Figure 6 ), since the pin 53 is provided on the turbine housing 4 having the same temperature as the nozzle ring 23, the temperature difference between the pin 53 and the nozzle ring 23 during operation is small, and the shaking of the two can be reduced.

[0074] Furthermore, the engagement portion 50A is the portion where the turbine housing 4 and the nozzle ring 23 engage. Therefore, if the engagement portion 50A is located radially inward of the circle C1, a portion of the engagement portion 50A (e.g., the pin 53) could interfere with the rotation of the nozzle vanes 21. In contrast, in the supercharger 1 of this embodiment, the engagement portion 50A is located radially outward of the circle C1, thereby preventing the engagement portion 50A from interfering with the rotation of the nozzle vanes 21. Furthermore, because the pin 53 is a clearance fit within the U-shaped groove 51, if a thermal expansion difference occurs between the variable nozzle unit 20 and the turbine housing 4, the pin 53 radially displaces within the U-shaped groove 51, thereby absorbing the thermal expansion difference.

[0075] (Second embodiment)

[0076] Figure 7 (a) is a perspective view of the nozzle ring 23 to which the engaging portion 50B is applied. Figure 7 (b) is a cross-sectional view showing an enlarged view of the engaging portion 50B. Figure 7 (c) is a view of the engaging portion 50B viewed from the direction of arrow VIIc. Figure 7 As shown in (a), the engaging portion 50B has the same U-shaped groove 51 as above. Figure 7 (b) and Figure 7 As shown in (c), the pin 53B of the engaging portion 50B is press-fitted into the inner wall 4a of the turbine housing 4 at a position facing the outermost edge 45a of the flange 45, extending radially inward from the inner wall 4a. The pin 53B has a circular cross-section with a diameter approximately equal to the width of the U-shaped groove 51. It is inserted into the U-shaped groove 51 along its depth, providing a clearance fit. This engaging portion 50B achieves the same operational advantages as the engaging portion 50A.

[0077] (Third embodiment)

[0078] Figure 8 (a) is a perspective view of the nozzle ring 23 to which the engaging portion 50C is applied. Figure 8 (b) is a cross-sectional view showing an enlarged view of the engaging portion 50C. Figure 8 (c) is a view of the engaging portion 50C viewed from the direction of arrow VIIIc. Figure 8 As shown in (a), the engaging portion 50C includes a pin 53C provided on the flange 45 of the nozzle ring 23. The pin 53C is pressed into the abutment surface 45b of the flange 45 that abuts against the flange receiving surface 47b, and extends axially from the abutment surface 45b toward the turbine side. Figure 8 (b) and Figure 8As shown in (c), the engaging portion 50C includes a pin hole 55 provided in the turbine housing 4 and into which the pin 53C is inserted. The pin hole 55 is provided on the flange receiving surface 47b of the ridge portion 47 and has a circular cross-section with approximately the same diameter as the pin 53C. The pin 53C is loosely fitted into the pin hole 55. This engaging portion 50C achieves the same functional effects as the engaging portion 50A. Alternatively, the positional relationship between the pin 53C and the pin hole 55 described above can be reversed, with the pin 53C formed on the flange receiving surface 47b of the ridge portion 47 and the corresponding pin hole 55 formed on the abutting surface 45b of the flange 45.

[0079] (Fourth embodiment)

[0080] Figure 9 (a) is a perspective view of the nozzle ring 23 to which the engaging portion 50D is applied. Figure 9 (b) is a cross-sectional view showing an enlarged view of the engaging portion 50D. Figure 9 (c) is a view of the engaging portion 50D viewed from the direction of arrow IXc. Figure 9 As shown in (a), the engaging portion 50D includes a pin 53D provided on the flange 45 of the nozzle ring 23. The pin 53D is pressed into the outermost edge surface 45a of the flange 45 and extends radially outward from the outermost edge surface 45a. Figure 9 (b) and Figure 9 As shown in (c), the engaging portion 50D includes a pin hole 55D provided in the turbine housing 4 and into which the pin 53D is inserted. The pin hole 55D is provided on the inner wall surface 4a of the turbine housing 4 at a position facing the outermost edge surface 45a of the flange 45. It has a circular cross-section with a diameter approximately the same as that of the pin 53D, and the pin 53D is loosely fitted into the pin hole 55D. This engaging portion 50D can also achieve the same functional effects as the engaging portion 50A. Alternatively, the positional relationship between the pin 53D and the pin hole 55D described above can be reversed, with the pin 53D formed on the inner wall surface 4a of the turbine housing 4 and the corresponding pin hole 55D formed on the abutting surface 45b of the flange 45.

[0081] (Fifth embodiment)

[0082] Figure 10 (a) is a perspective view of the nozzle ring 23 to which the engaging portion 50E is applied. Figure 10 (b) is a cross-sectional view showing an enlarged view of the engaging portion 50E. Figure 10 (c) is a view of the engaging portion 50E viewed from the direction of arrow Xc. Figure 10As shown in (a), the engaging portion 50E includes a protrusion 57 formed on the flange 45 of the nozzle ring 23. The protrusion 57 protrudes from the abutment surface 45b of the flange 45 toward the turbine side and has a rectangular parallelepiped shape extending radially over the entire radial width of the flange 45. The protrusion 57 may also be formed as a portion remaining after cutting the abutment surface 45b. In addition, as shown in FIG. Figure 10 (b) and Figure 10 As shown in (c), the engaging portion 50E has a recess 59 corresponding to the above-mentioned protrusion 57. The recess 59 is formed on the flange receiving surface 47b in a shape in which the protrusion 57 is just embedded. That is, the recess 59 is formed on the flange receiving surface 47b in a rectangular parallelepiped shape having a circumferential width substantially the same as that of the protrusion 57. The recess 59 is also a groove extending radially over the entire radial width of the ridge portion 47. The protrusion 57 is loosely fitted with respect to the recess 59. By means of such an engaging portion 50E, the same functional effect as that of the engaging portion 50A can be obtained. In addition, the recess 59 is not limited to a rectangular parallelepiped shape, as long as it has two surfaces that clamp the protrusion 57 in the circumferential direction. In addition, as long as the protrusion 57 protrudes from the abutting surface 45b toward the turbine side, it is not limited to a rectangular parallelepiped shape, but may be other shapes. Alternatively, the positional relationship between the protrusion 57 and the recess 59 may be reversed, with the protrusion 57 being formed on the flange receiving surface 47 b of the ridge 47 and the corresponding recess 59 being formed on the abutting surface 45 b of the flange 45 .

[0083] While the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments and can be modified without departing from the spirit of the claims. The structures of the various embodiments can also be combined as appropriate.

[0084] For example, while the engaging portions 50A-50E in the above-described embodiments are portions that engage the turbine housing 4 and the nozzle ring 23, the engaging portions 50A-50E may also be portions that engage the bearing housing 13 and the nozzle ring 23. In this case, for example, the pin 53 of the engaging portion 50A may be press-fitted into the bearing housing 13 and inserted into the U-shaped groove 51. In other words, as long as the engaging portions 50A-50E are located radially outside the circle C1, the nozzle ring 23 can engage with either the turbine housing 4 or the bearing housing 13. As long as these engaging portions 50A-50E are located radially outside the circle C1, the circumferential displacement of the variable nozzle unit 20 caused by the circumferential play of the engaging portions 50A-50E is minimized, as described above, thereby suppressing fluctuations in the flow rate of the exhaust gas from the nozzle flow path 19.

[0085] Furthermore, in the above-described embodiments, the engaging portions 50A to 50E are provided at one location per variable nozzle unit 20 . However, the engaging portions 50A to 50E may be provided at a plurality of locations in the circumferential direction per variable nozzle unit 20 .

[0086] Description of Reference Numerals

[0087] 1...variable capacity supercharger; H...rotation axis; 4...turbine housing; 6...turbine impeller; 19...nozzle flow path; 21...nozzle vanes; 20...variable nozzle unit; 25...driving mechanism; 43...disc spring (force-applying portion); 45...flange; 47...ribbed portion (flange receiving portion); 50A, 50B, 50C, 50D, 50E...engaging portion; 51...U-shaped groove; 53, 53B, 53C, 53D...pin; 55, 55D...pin holes; 57...protrusion; 59...recess.

Claims

1. A variable capacity supercharger, characterized in that: have: a turbine housing housing a turbine impeller; a variable nozzle unit having a nozzle vane disposed in a nozzle flow path provided around the turbine impeller in the turbine housing and having a drive mechanism for driving the nozzle vane; a force applying portion for applying force to the variable nozzle unit along the rotation axis direction of the turbine impeller and pressing the variable nozzle unit against a portion of the turbine housing; as well as an engaging portion for engaging the variable nozzle unit with a predetermined portion so as to restrict displacement of the variable nozzle unit in the rotational circumferential direction of the turbine impeller, The engagement portion is located in a region radially outward of a movable range of the nozzle vanes in the radial direction of rotation of the turbine impeller.

2. The variable capacity supercharger according to claim 1, characterized in that: The variable nozzle unit has a flange, which is arranged to protrude most radially outward in the variable nozzle unit. The flange is pressed against the flange receiving portion of the turbine housing along the rotation axis direction by the biasing force of the biasing portion. In the engagement portion, a portion of the flange is directly or indirectly engaged with the predetermined location.

3. The variable capacity supercharger according to claim 2, characterized in that: The engaging portion has: a groove formed so as to be cut from the outermost edge surface of the flange toward the inner peripheral side; and A pin extends from the turbine housing and is inserted into the slot.

4. The variable capacity supercharger according to claim 2, characterized in that: The engaging portion has: a pin extending from one side of the flange or the turbine housing; and A pin hole is provided on the other of the flange and the turbine housing and is used to insert the pin.

5. The variable capacity supercharger according to claim 2, characterized in that: The engaging portion has: a protrusion provided on one side of the flange or the flange receiving portion; and The recessed portion is provided on the other side of the flange or the flange receiving portion and is used for the protrusion to be embedded.

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