Variable displacement turbocharger

Abstract

This variable displacement turbocharger comprises: a turbine housing that accommodates a turbine impeller; a variable nozzle unit including a nozzle vane disposed in a nozzle flow path provided around the turbine impeller inside the turbine housing, and a driving mechanism that drives the nozzle vane; a dish spring that biases the variable nozzle unit in an axial direction to be pressed against a portion of the turbine housing; a pin extending from a bearing housing; and a U-shaped groove that is provided in the variable nozzle unit and into which the tip end of the pin is inserted. The U-shaped groove has a pair of inner wall surfaces that form parallel planes intersecting the circumferential direction, and that sandwich the tip end of the pin in the circumferential direction. The tip end of the pin is press-fitted between the inner wall surfaces.

Description

Technical Field

[0001] The present disclosure relates to a variable displacement supercharger.

Background Art

[0002] Conventionally, variable displacement superchargers described in Patent Documents 1 and 2 below are known. The supercharger of Patent Document 1 has a variable nozzle unit for adjusting the opening degree of the nozzle flow path of a turbine. A disc spring is installed between the variable nozzle unit and the bearing housing. The variable nozzle unit is biased by the disc spring and pressed against the turbine housing to be axially positioned. Further, in the supercharger of Patent Document 2 below, a regulating pin fixed to the bearing housing is inserted into a guide groove formed in the variable nozzle unit, and the variable nozzle unit is positioned in a plane orthogonal to the axial direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, during the operation of the supercharger, the disc spring load decreases due to thermal deformation of the disc spring and a decrease in Young's modulus. As a result, the frictional force between the variable nozzle unit and the turbine housing decreases, and there is a possibility that the variable nozzle unit may be circumferentially displaced by the amount of circumferential play between the regulating pin and the guide groove. And if the variable nozzle unit is circumferentially displaced, a change in the gas flow rate will occur.

[0005] Therefore, the present disclosure describes a variable displacement supercharger that suppresses changes in the gas flow rate during operation. [Means for solving the problem]

[0006] The gist of a variable displacement turbocharger according to one aspect of this disclosure is as follows:

[0007] [1] A turbine housing that houses the turbine blades, A variable nozzle unit having nozzle vanes arranged in a nozzle channel provided around the turbine impeller within the turbine housing, and a drive mechanism for driving the nozzle vanes, A biasing unit that biases the variable nozzle unit in the direction of the rotation axis of the turbine blade and presses it against a part of the turbine housing, A pin extending from the bearing housing that houses the bearing of the turbine blade, The variable nozzle unit is provided with a pin insertion portion into which the tip of the pin is inserted, The pin insertion portion has parallel planes that intersect the rotational direction of the turbine blade and has a pair of inner wall surfaces that sandwich the tip of the pin in the rotational direction. A variable displacement supercharger in which the tip of the pin is press-fitted between the inner wall surfaces. [Effects of the Invention]

[0008] The variable displacement turbocharger of this disclosure can suppress changes in gas flow rate during operation. [Brief explanation of the drawing]

[0009] [Figure 1] This is a cross-sectional view showing the variable displacement turbocharger of this embodiment. [Figure 2] This is an exploded perspective view showing the variable nozzle unit, etc. [Figure 3] This is a plan view of the variable nozzle unit as seen axially from the bearing housing side. [Figure 4] This is a magnified cross-sectional view showing the vicinity of the variable nozzle unit of a variable displacement turbocharger. [Figure 5](a) is a perspective view showing an example of a pin, (b) is a perspective view showing another example of the pin, and (c) is a perspective view showing still another example of the pin. [Figure 6] (a) is a view showing an enlarged view of the vicinity of the engaging portion of the nozzle ring according to a modified example, and (b) is a perspective view showing a nozzle ring according to another modified example.

Mode for Carrying Out the Invention

[0010] The gist of the variable displacement supercharger according to one aspect of the present disclosure is as follows.

[0011] 〔1〕A turbine housing that houses a turbine impeller, A variable nozzle unit having a nozzle vane disposed in a nozzle flow path provided around the turbine impeller within the turbine housing, and a drive mechanism that drives the nozzle vane, A biasing portion that biases the variable nozzle unit in the rotational axis direction of the turbine impeller and presses it against a part of the turbine housing, A pin extending from a bearing housing that houses a bearing of the turbine impeller, A pin insertion portion provided in the variable nozzle unit into which a tip portion of the pin is inserted, The pin insertion portion has a pair of inner wall surfaces that form a parallel plane intersecting the circumferential direction of rotation of the turbine impeller and sandwich the tip portion of the pin in the circumferential direction of rotation, The tip portion of the pin is press-fitted between the inner wall surfaces, variable displacement supercharger.

[0012] 〔2〕The pin insertion portion is A groove or a long hole extending in a direction intersecting the circumferential direction of rotation, the variable displacement supercharger according to 〔1〕.

[0013] 〔3〕The pin is a member whose dimension in the facing direction between the inner wall surfaces can elastically vary, the variable displacement supercharger according to 〔1〕 or 〔2〕. <C

[0014] 〔4〕The pin is a coil pin whose outer diameter can elastically vary, and is the variable displacement supercharger according to any one of 〔1〕to 〔3〕.

[0015] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view taken along a cross-section including the rotation axis H of the variable displacement supercharger 1. The variable displacement supercharger 1 is applied to, for example, an internal combustion engine of a ship or a vehicle.

[0016] As shown in FIG. 1, the supercharger 1 includes a turbine 2 and a compressor 3. The turbine 2 includes a turbine housing 4 and a turbine impeller 6 housed in the turbine housing 4. The turbine housing 4 has a scroll flow path 16 extending in the circumferential direction around the turbine impeller 6. The compressor 3 includes a compressor housing 5 and a compressor impeller 7 housed in the compressor housing 5. The compressor housing 5 has a scroll flow path 17 extending in the circumferential direction around the compressor impeller 7.

[0017] The turbine impeller 6 is provided at one end of the 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 a bearing 15, and the rotating shaft 14, the turbine impeller 6, and the compressor impeller 7 rotate around the rotation axis H as an integral rotating body.

[0018] The turbine housing 4 is provided with an exhaust gas inlet 8 and an exhaust gas outlet 10. Exhaust gas discharged from an internal combustion engine (not shown) flows into the turbine housing 4 through the exhaust gas inlet 8, flows into the turbine impeller 6 through the scroll flow path 16, and rotates the turbine impeller 6. Thereafter, the exhaust gas flows out of the turbine housing 4 through the exhaust gas outlet 10.

[0019] The compressor housing 5 is provided with an intake port 9 and a discharge port 11. As the turbine impeller 6 rotates as described above, the compressor impeller 7 rotates via the rotating shaft 14. The rotating compressor impeller 7 draws in outside air through the intake port 9. This air is compressed as it passes through the compressor impeller 7 and the scroll passage 17 and is discharged from the discharge port 11. The compressed air discharged from the discharge port 11 is supplied to the internal combustion engine mentioned above.

[0020] Further explanation will be given regarding the turbine 2 of the supercharger 1. In the following explanation, when we simply refer to "axial direction," "radial direction," and "circumferential direction," we mean the rotational axis direction (rotational axis H direction), rotational radial direction, and rotational circumferential direction, respectively, of the turbine impeller 6. Also, when we refer to "upstream" and "downstream," we mean the upstream and downstream of the exhaust gas in the turbine 2. Furthermore, in the rotational axis H direction, the turbine 2 side of the supercharger 1 (left side in Figure 1) may simply be referred to as the "turbine side," and the compressor 3 side (right side in Figure 1) may simply be referred to as the "compressor side."

[0021] The turbine 2 of the supercharger 1 is provided with a nozzle passage 19 that connects the scroll passage 16 and the turbine impeller 6, which is located around the turbine impeller 6. The nozzle passage 19 is provided with a plurality of movable nozzle vanes 21. The plurality of nozzle vanes 21 are arranged at roughly equal intervals on a circumference centered on the rotation axis H. Each nozzle vane 21 rotates synchronously around an axis NX parallel to the rotation axis H. As the plurality of nozzle vanes 21 rotate as described above, the gap between adjacent nozzle vanes 21 expands and contracts, and the opening degree of the nozzle passage 19 is adjusted.

[0022] To drive the nozzle vanes 21 as described above, the turbine 2 is equipped with a variable nozzle unit 20. The variable nozzle unit 20 is fitted inside the turbine housing 4. The variable nozzle unit 20 has the above-mentioned plurality of nozzle vanes 21 and two nozzle rings 23 and 27 that sandwich the nozzle vanes 21 in the axial direction. The two nozzle rings 23 and 27 are arranged in the axial direction, with nozzle ring 23 positioned closer to the compressor than nozzle ring 27. The nozzle rings 23 and 27 each form a ring shape centered on the axis of rotation H and are arranged to surround the turbine impeller 6 in the circumferential direction. The region sandwiched in the axial direction by the two nozzle rings 23 and 27 constitutes the aforementioned nozzle flow path 19. The nozzle rings 23 and 27 are connected to each other in the axial direction via a plurality of connecting pins 29, and the axial dimensional accuracy of the nozzle flow path 19 is ensured by manufacturing the dimensions of the connecting pins 29 with high precision.

[0023] Furthermore, the variable nozzle unit 20 has a drive mechanism 25 for driving the nozzle vanes 21. The drive mechanism 25 is housed in the space between the nozzle ring 23 and the bearing housing 13 and transmits driving force from an external actuator (not shown) to the nozzle vanes 21.

[0024] The drive mechanism 25 of the variable nozzle unit 20 will be described in more detail with reference to Figures 2 and 3. Figure 2 is an exploded perspective view showing the variable nozzle unit 20 and the heat shield 41 and disc spring 43, which will be described later. Figure 3 is a plan view of the variable nozzle unit 20 as seen axially from the bearing housing 13 side. The nozzle ring 23 is provided with bearing holes 31 that penetrate axially, and the pivot shaft 21a of each nozzle vane 21 is rotatably inserted through each bearing hole 31. In the example shown in the figure, the nozzle vanes 21 are arranged at equal intervals on the circumference, but it is not essential to arrange the nozzle vanes 21 at equal intervals.

[0025] The drive mechanism 25 comprises a drive ring 33, a nozzle link plate 35, and a drive link plate 37. The drive ring 33 is ring-shaped and extends along the circumference centered on the rotation axis H, and is positioned along the compressor-side surface of the nozzle ring 23. The drive ring 33 is rotatable around the rotation axis H relative to the nozzle ring 23. Engaging portions 33a, which engage with each nozzle link plate 35, are provided on the drive ring 33 at predetermined intervals in the circumferential direction.

[0026] There are as many nozzle link plates 35 as there are nozzle vanes 21. The nozzle link plates 35 are attached to the ends of the pivot shafts 21a of the nozzle vanes 21 and extend radially outward from these ends. More specifically, each pivot shaft 21a of the nozzle vanes 21 is inserted into a bearing hole 31, and each end of the pivot shaft 21a protrudes from the nozzle ring 23 towards the compressor. The inner end of each nozzle link plate 35 is attached to each of these protruding ends of the pivot shaft 21a. The outer end of each nozzle link plate 35 engages with the engagement portion 33a of the drive ring 33.

[0027] Furthermore, the drive ring 33 is provided with one input-side engaging portion 33b. The input-side engaging portion 33b is located between a pair of engaging portions 33a. The outer peripheral end of the drive link plate 37 engages with this input-side engaging portion 33b, and the inner peripheral end of the drive link plate 37 is connected to the drive shaft 39 (Figure 3) of an external actuator.

[0028] When an external actuator rotates the drive link plate 37 around an axis parallel to the rotation axis H via the drive shaft 39, the outer end of the drive link plate 37 pushes the input-side engaging portion 33b in the circumferential direction. This causes the drive ring 33 to rotate around the rotation axis H, and each engaging portion 33a of the drive ring 33 pushes the outer end of each nozzle link plate 35 in the circumferential direction. As a result, each nozzle link plate 35 rotates around the axis NX, and each nozzle vane 21 fixed to each nozzle link plate 35 rotates around the axis NX.

[0029] Next, the structure for positioning the variable nozzle unit 20 within the turbine housing 4 will be described. As shown in Figures 1 and 2, a heat shield 41 is provided between the turbine impeller 6 and the bearing housing 13. The heat shield 41 shields against radiant heat from the high-temperature turbine housing 4, thereby suppressing the temperature rise of the bearing housing 13. The heat shield 41 is an annular shape that surrounds the rotating shaft 14 in the circumferential direction. The heat shield 41 is fitted into the central opening of the nozzle ring 23 from the bearing housing 13 side.

[0030] A disc spring 43 is sandwiched between the heat shield 41 and the bearing housing 13. A rotating shaft 14 is inserted through the hole in the center of the disc spring 43, and the disc spring 43 is positioned along a conical surface with the rotation axis H as the conical axis. In the axial direction, one end of the disc spring 43 is in contact with the bearing housing 13 and the other end is in contact with the heat shield 41. The disc spring 43 generates a repulsive force that expands the gap between the bearing housing 13 and the heat shield 41 in the axial direction. This disc spring 43 biases the variable nozzle unit 20 and the heat shield 41 axially toward the turbine housing 4.

[0031] Figure 4 is an enlarged cross-sectional view showing the vicinity of the variable nozzle unit 20 shown in Figure 1. The nozzle ring 23 has a flange 45 formed to protrude outward. The turbine housing 4 has a protruding ridge 47 that receives the flange 45. The protruding ridge 47 protrudes inward from the inner wall surface of the turbine housing 4 and extends in a ring shape along the circumference centered on the axis of rotation H. The inner diameter of the protruding ridge 47 is formed to be smaller than the outer diameter of the flange 45, and the flange 45 abuts against the protruding ridge 47 from the bearing housing 13 side.

[0032] 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 protruding portion 47. The variable nozzle unit 20 is then positioned and fixed in the axial direction by the flange 45 being pressed against the protruding portion 47. In addition, the variable nozzle unit 20 is fixed with a certain degree of force in the in-plane direction perpendicular to the axial direction by the frictional force between the flange 45 and the protruding portion 47. However, when a difference in thermal expansion occurs between the variable nozzle unit 20 and the turbine housing 4, this difference can be absorbed by the sliding of the flange 45 and the protruding portion 47.

[0033] Next, the circumferential and radial positioning of the variable nozzle unit 20 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 the frictional force between the flange 45 and the protruding portion 47 (flange receiving portion). Here, conventionally, the structure described in Patent Document 2 above can be adopted as a structure to further restrict the circumferential displacement of this type of variable nozzle unit. In the structure of Patent Document 2, a regulating pin is provided that extends from the bearing housing toward the turbine side. The nozzle ring of the variable nozzle unit is provided with a guide groove that extends generally in the radial direction. By inserting the regulating pin into this guide groove, the variable nozzle unit is positioned in the in-plane direction perpendicular to the axial direction.

[0034] Let's consider the case where the structure of Patent Document 2 described above is adopted for the turbocharger 1. During operation of the turbocharger 1, the disc spring load due to the disc spring 43 (biasing part) decreases due to thermal deformation and decrease in Young's modulus. As a result, the frictional force between the flange 45 and the protruding part 47 decreases, and a circumferential displacement (rotational displacement around the rotation axis H) of the variable nozzle unit 20 may occur by the amount of circumferential play between the regulating pin and the guide groove in the structure of Patent Document 2. If a circumferential displacement of the variable nozzle unit 20 occurs, a change in the exhaust gas flow rate will occur, especially when the nozzle passage 19 is closed. Therefore, the turbocharger 1 is equipped with the following configuration in order to suppress the circumferential displacement of the variable nozzle unit 20 during operation.

[0035] As shown in Figures 2 to 4, a ring-shaped projection 49 is formed in the center of the compressor-side surface of the nozzle ring 23, protruding toward the compressor with a stepped portion from the surrounding area. The drive ring 33 is arranged to concentrically surround this ring-shaped projection 49. The outer peripheral edge surface 49a of the ring-shaped projection 49, corresponding to the stepped portion, forms a cylindrical surface with a diameter slightly smaller than the inner diameter of the drive ring 33, and guides the rotation of the drive ring 33.

[0036] A U-shaped groove 51 is formed in this ring-shaped projection 49. The U-shaped groove 51 extends radially across the entire thickness of the ring-shaped projection 49 and is formed to cut inward from the outer peripheral edge surface 49a. The U-shaped groove 51 has a pair of inner wall surfaces 51a, 51a facing each other in the circumferential direction. The inner wall surfaces 51a, 51a are parallel planes to each other.

[0037] Furthermore, a pin 53 extends axially toward the turbine from the turbine-side surface of the bearing housing 13. The pin 53 and the U-shaped groove 51 are located at the same circumferential position. The pin 53 is a round bar-shaped member, and its diameter is approximately equal to the distance between the inner wall surfaces 51a (the groove width of the U-shaped groove 51). Alternatively, the diameter of the pin 53 is slightly larger than the distance between the inner wall surfaces 51a. The pin 53 may be a solid pin 53A with a solid circular cross-section, as shown in Figure 5(a). The pin 53 may also be a spring pin 53B with a C-shaped cross-section with a part of the annular missing, as shown in Figure 5(b). The pin 53 may also be a coil pin 53C in which the member is wound in multiple coils, as shown in Figure 5(c).

[0038] The base end of the pin 53 is press-fitted into the bearing housing 13. The tip 53p of the pin 53 is inserted into the U-shaped groove 51 (pin insertion part) and is sandwiched circumferentially between the inner wall surfaces 51a. This structure positions the variable nozzle unit 20 circumferentially relative to the bearing housing 13 via the pin 53. There is also a radial gap between the pin 53 and the bottom of the U-shaped groove 51. The contact area between the pin 53 and the inner wall surfaces 51a, 51a is the radially intermediate portion of the inner wall surfaces 51a, 51a. That is, the mutually parallel inner wall surfaces 51a, 51a exist from a position on the inner circumference side to a position on the outer circumference side (outer peripheral edge surface 49a) of the contact area with the pin 53.

[0039] More specifically, the tip 53p of the pin 53 is press-fitted into the U-shaped groove 51. That is, the pin 53 is interlocked between the inner wall surfaces 51a in the circumferential direction, and the pin 53 is fixed to the U-shaped groove 51 by surface pressure from the inner wall surfaces 51a, 51a in the circumferential direction. Furthermore, as mentioned above, there is a radial gap between the pin 53 and the bottom of the U-shaped groove 51, so the pin 53 can move radially within the U-shaped groove 51 against the frictional force with the inner wall surfaces 51a, 51a caused by the surface pressure.

[0040] As shown in Figures 2 and 3, the supercharger 1 has two sets of pins 53 and U-shaped grooves 51 as described above, meaning there are two engagement portions 50 where the pins 53 and U-shaped grooves 51 engage. Note that the engagement portions 50 are not shown in Figure 1.

[0041] The effects of the turbocharger 1 equipped with the U-shaped groove 51 and pin 53 described above will now be explained. In the turbocharger 1, the pin 53 extending from the bearing housing 13 is inserted into the U-shaped groove 51 of the variable nozzle unit 20, thereby restricting the circumferential displacement of the variable nozzle unit 20. As mentioned above, the tip 53p of the pin 53 is press-fitted into the U-shaped groove 51, and the pin 53 is fixed by surface pressure applied circumferentially from the inner wall surfaces 51a, 51a. Therefore, there is no circumferential play between the pin 53 and the U-shaped groove 51, and circumferential displacement of the variable nozzle unit 20 due to this circumferential play is almost nonexistent. Consequently, in the turbocharger 1, circumferential displacement of the variable nozzle unit 20 during operation is suppressed, and changes in the flow rate of exhaust gas in the nozzle passage 19 can be suppressed.

[0042] Furthermore, if a circular hole into which a pin 53 is press-fitted were provided instead of the U-shaped groove 51, the variable nozzle unit 20 would also be constrained radially by the pin 53. In that case, when a difference in thermal expansion occurs between the variable nozzle unit 20 and the bearing housing 13, thermal deformation of the variable nozzle unit 20 centered on the engaging portion 50 would occur, potentially causing deformation of the throat of the nozzle passage 19 and resulting in a change in the exhaust gas flow rate of the nozzle passage 19. In contrast, by employing the U-shaped groove 51, the pin 53 can move radially within the U-shaped groove 51 against the frictional force with the inner wall surfaces 51a, 51a. Therefore, the above-mentioned difference in thermal expansion is absorbed, and as a result, changes in the exhaust gas flow rate of the nozzle passage 19 during operation can be suppressed.

[0043] Furthermore, if a solid pin 53A (Figure 5(a)) is used as pin 53, it is preferable compared to a spring pin 53B (Figure 5(b)) or a coil pin 53C (Figure 5(c)) because the strength of the pin 53 is higher.

[0044] Now, let's consider the press-fitting load of the pin 53 into the U-shaped channel 51. If this press-fitting load is high, the frictional force between the pin 53 and the inner wall surfaces 51a, 51a is large, and as the pin 53 moves inside the U-shaped channel 51 against this frictional force, wear of the pin 53 or the inner wall surfaces 51a, 51a is likely to progress. And if the pin 53 or the inner wall surfaces 51a, 51a wears down, a circumferential gap will be created between the pin 53 and the inner wall surfaces 51a, 51a, and circumferential play may occur.

[0045] To address this problem, the spring pin 53B and coil pin 53C are components whose dimensions in the circumferential direction (facing direction) of the inner wall surfaces 51a, 51a can be elastically varied. In particular, the coil pin 53C is a component whose outer diameter can be elastically varied. Therefore, compared to the solid pin 53A, the press-fitting load required to press-fit the spring pin 53B and coil pin 53C into the U-shaped groove 51 is relatively low. Thus, when the spring pin 53B or coil pin 53C is used, the frictional force between the pin 53 and the inner wall surfaces 51a, 51a is relatively small, and the wear of the pin 53 or the inner wall surfaces 51a, 51a as described above is suppressed. Furthermore, even if the pin 53 or the inner wall surfaces 51a, 51a wear down, the pin 53 elastically expands in diameter, reducing the gap due to wear, thus suppressing circumferential play.

[0046] Furthermore, if the press-fitting load of the pin 53 into the U-shaped groove 51 is high, the axial frictional force between the pin 53 and the inner wall surfaces 51a, 51a will also be large. This axial frictional force hinders the biasing force that the disc spring 43 exerts on the variable nozzle unit 20 in the axial direction, and weakens the force that presses the flange 45 against the protruding portion 47, thus reducing the frictional force between the flange 45 and the protruding portion 47. Therefore, in order to ensure a biasing force that is always greater than the axial frictional force between the pin 53 and the inner wall surfaces 51a, 51a, the load of the disc spring 43 must be designed to be large and with tight tolerances, which makes the design less feasible.

[0047] To address this problem, if a spring pin 53B or a coil pin 53C is used, the axial frictional force with the inner wall surfaces 51a, 51a is relatively smaller compared to a solid pin 53A. Therefore, the obstruction of the axial biasing force by the disc spring 43 as described above is also suppressed. As a result, the load and tolerances of the disc spring 43 as described above are relaxed, and the feasibility of the design is improved. For these reasons, it is preferable to use a spring pin 53B or a coil pin 53C.

[0048] Furthermore, if a spring pin 53B or a coil pin 53C is used, the press-fitting load of the pin 53 into the U-shaped groove 51 is relatively low, resulting in good assembly of the engagement portion 50. However, in the case of a spring pin 53B, the strength of the pin 53 depends on the orientation of the pin 53, so it is necessary to adjust the orientation of the pin 53 during assembly. In comparison, the coil pin 53C has higher isotropy in terms of strength, etc., and there is less need to adjust the orientation of the pin 53 during assembly, thus offering superior assembly.

[0049] Although embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments described above, and may be modified without changing the gist of each claim. The configurations of each embodiment may be used in appropriate combinations.

[0050] For example, as shown in Figure 6(a), the ring-shaped projection 49 of the nozzle ring 23 may be provided with an elongated hole 61 into which the tip 53p of the pin 53 is press-fitted, instead of the U-shaped groove 51. The elongated hole 61 is an elongated hole extending in the radial direction and has a pair of inner wall surfaces 51a, 51a similar to those of the U-shaped groove 51. Alternatively, as shown in Figure 6(b), the ring-shaped projection 49 of the nozzle ring 23 may be provided with a groove 65 into which the tip 53p of the pin 53 is press-fitted, instead of the U-shaped groove 51. The groove 65 is a groove extending radially across the entire radial width of the ring-shaped projection 49 and has a pair of inner wall surfaces 51a, 51a similar to those of the U-shaped groove 51.

[0051] Furthermore, in each of the above embodiments, two engagement portions 50 are provided for one variable nozzle unit 20, but it is sufficient to provide at least one engagement portion 50 for one variable nozzle unit 20, and three or more engagement portions 50 may be provided for one variable nozzle unit 20. [Explanation of symbols]

[0052] 1. Variable Displacement Turbocharger H rotation axis 4 Turbine Housing 6 Turbine blade vehicle 13 Bearing Housing 19 Nozzle flow path 21 Nozzle vanes 20 Variable nozzle unit 25 Drive mechanism 43 Disc spring (biasing part) 45 Flange 47. Protruding section (flange receiving section) 51 U-shaped groove (pin insertion part) 53, 53A, 53B, 53C pins 53C Coil Pin 53p tip 61. Slotted hole (pin insertion part) 65 grooves (pin insertion area)

Claims

1. A turbine housing that houses the turbine blades, A variable nozzle unit having nozzle vanes arranged in a nozzle channel provided around the turbine impeller within the turbine housing, and a drive mechanism for driving the nozzle vanes, A biasing unit that biases the variable nozzle unit in the direction of the rotation axis of the turbine blade and presses it against a part of the turbine housing, A pin extending from the bearing housing that houses the bearing of the turbine blade, The variable nozzle unit is provided with a pin insertion portion into which the tip of the pin is inserted, The pin insertion portion has parallel planes that intersect the rotational direction of the turbine blade and has a pair of inner wall surfaces that sandwich the tip of the pin in the rotational direction. A variable displacement supercharger in which the tip of the pin is press-fitted between the inner wall surfaces.

2. The aforementioned pin insertion portion is The variable displacement supercharger according to claim 1, wherein the groove or elongated hole extends in a direction intersecting the circumferential direction of rotation.

3. The variable displacement supercharger according to claim 1, wherein the pin is a member whose dimensions in the direction of opposition between the inner wall surfaces can be elastically varied.

4. The variable displacement supercharger according to claim 1, wherein the pin is a coil pin whose outer diameter can be elastically varied.

Images