Variable displacement turbocharger

Abstract

A variable-capacity turbocharger has: a turbine housing that accommodates a turbine impeller; a variable nozzle assembly with a nozzle vane arranged in a nozzle flow channel provided around the turbine impeller in the turbine housing, and a drive mechanism designed to drive the nozzle vane; a disc spring designed to bias the variable nozzle assembly in an axial direction so that it is pressed against a section of the turbine housing; a pin extending from the bearing housing; and a U-groove provided on the variable nozzle assembly that allows the insertion of a distal end of the pin.The U-groove has a pair of inner wall surfaces designed as parallel flat planes intersecting in the circumferential direction, and which hold the distal end of the pin between them in the circumferential direction, with the distal end of the pin being press-fitted between the inner wall surfaces.

Description

Technical field

[0001] The present disclosure relates to a variable displacement turbocharger (variable capacity turbocharger). Background of the state of the art

[0002] Variable-capacity turbochargers are known, as described in patent documents 1 and 2 mentioned below. The turbocharger described in patent document 1 has a variable nozzle unit for controlling the opening of a turbine's nozzle flow channel. A disc spring is provided between the variable nozzle unit and a bearing housing. The variable nozzle unit is pre-tensioned by the disc spring and pressed against the turbine housing so that it is positioned in the axial direction. In the turbocharger described in patent document 2 below, a limiting pin, fixed to the bearing housing, is inserted into a guide groove formed in the variable nozzle unit, thus positioning the variable nozzle unit in a plane perpendicular to the axial direction. List of state-of-the-art patent documents Patent document 1: Unexamined Japanese patent application with publication number JP 2013-68153 Patent document 2: International publication WO 2021 / 246294 Summary of the invention: Technical problem

[0003] However, the load on the disc spring will decrease during turbocharger operation because the disc spring deforms due to heating or its modulus of elasticity decreases. This would reduce the frictional force between the variable nozzle assembly and the turbine housing, causing a circumferential displacement of the variable nozzle assembly by precisely the amount of clearance (gap) between the limiting pin and the guide notch. This circumferential displacement of the variable nozzle assembly will result in a change in the gas flow rate.

[0004] The present disclosure now describes a variable-capacity turbocharger designed to suppress changes in the gas flow rate during operation. Solution to the problem

[0005] A key feature of a variable-capacity turbocharger, according to one aspect of the present disclosure, is as follows.

[0006] [1] A variable capacity turbocharger with: a turbine housing that accommodates a turbine impeller; a variable nozzle unit with a nozzle vane arranged in a nozzle flow channel provided around the turbine impeller in the turbine housing, and a drive mechanism designed to drive the nozzle vane; a pre-tensioning section designed to pre-tension the variable nozzle unit in one direction of a rotational axis of the turbine impeller so that it is pressed against a section of the turbine housing; a pin extending from a bearing housing that accommodates a bearing of the turbine impeller; and a pin insertion section provided on the variable nozzle unit, which allows the insertion of a distal end of the pin.

[0007] The pin insertion section has a pair of inner wall surfaces designed as parallel flat planes that intersect the circumferential direction of rotation of the turbine impeller and that hold the distal end of the pin between them in the circumferential direction of rotation, and the distal end of the pin is press-fitted between the inner wall surfaces. Advantageous effects of the invention

[0008] The variable-capacity turbocharger of the present disclosure can suppress a change in the gas flow rate during operation. Brief description of the drawings Fig. Figure 1 shows a cross-sectional view of a variable-capacity turbocharger according to this embodiment. Fig. Figure 2 shows a perspective exploded view of a variable nozzle unit, etc. Fig. Figure 3 shows a top view of the variable nozzle unit viewed in the axial direction from one side of a bearing housing. Fig. Figure 4 shows an enlarged cross-sectional view of an area around the variable-capacity turbocharger's variable-capacity nozzle unit. Fig. Figure 5(a) shows a perspective view of an exemplary pen, Fig. Figure 5(b) shows a perspective view of another exemplary pen, and Fig. Figure 5(c) shows a perspective view of yet another exemplary pen. Fig. Figure 6(a) shows an enlarged view of an area on and around the engagement section of the nozzle ring according to a modified example, and Fig. Figure 6(b) shows a perspective view of a nozzle ring according to another modified example. Description of the exemplary implementations

[0009] A key feature of a variable-capacity turbocharger, according to one aspect of the present disclosure, is as follows.

[0010] [1] A variable capacity turbocharger with: a turbine housing that accommodates a turbine impeller; a variable nozzle unit with a nozzle vane arranged in a nozzle flow channel provided around the turbine impeller in the turbine housing, and a drive mechanism designed to drive the nozzle vane; a pre-tensioning section designed to pre-tension the variable nozzle unit in one direction of a rotational axis of the turbine impeller so that it is pressed against a section of the turbine housing; a pin extending from a bearing housing that accommodates a bearing of the turbine impeller; and a pin insertion section provided on the variable nozzle unit, which allows the insertion of a distal end of the pin.

[0011] The pin insertion section has a pair of inner wall surfaces designed as parallel flat planes that intersect the circumferential direction of rotation of the turbine impeller and that hold the distal end of the pin between them in the circumferential direction of rotation, and The distal end of the pin is press-fitted between the inner wall surfaces.

[0012] [2] The variable capacity turbocharger according to [1], wherein the pin insertion section is a notch or elongated hole extending in a direction intersecting the circumferential direction of rotation.

[0013] [3] The variable capacity turbocharger according to [1] to or [2], wherein the pin is an element whose dimension is elastically variable in the direction in which the inner wall surfaces are opposite each other.

[0014] [4] Variable capacity turbocharger according to one of [1] to [3], wherein the pin is a winding pin whose outer diameter is elastically variable.

[0015] Exemplary embodiments of the present disclosure are described below with reference to the drawings. Fig. Figure 1 shows a cross-sectional view along a rotational axis H of the variable-capacity turbocharger 1. The variable-capacity turbocharger 1 is typically applicable to an internal combustion engine of ships or vehicles.

[0016] As this is in Fig. As shown in Figure 1, the turbocharger 1 has a turbine 2 and a compressor 3. The turbine 2 has a turbine housing 4 and a turbine impeller 6, which is housed in the turbine housing 4. The turbine housing 4 has a spiral flow channel 16 that extends circumferentially around the turbine impeller 6. The compressor 3 has a compressor housing 5 and a compressor impeller 7, which is housed in the compressor housing 5. The compressor housing 5 has a spiral flow channel 17 that extends circumferentially around the compressor impeller 7.

[0017] The turbine impeller 6 is located at one end of a rotating shaft 14, and the compressor impeller 7 is located 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 by means of a bearing 15, causing the rotating shaft 14, the turbine impeller 6, and the compressor impeller 7 to rotate about the axis of rotation H as a single, continuous unit.

[0018] The turbine housing 4 is equipped with an exhaust gas inlet 8 and an exhaust gas outlet 10. Exhaust gas emitted from an internal combustion engine (not shown) flows through the exhaust gas inlet 8 into the turbine housing 4 and through the spiral flow channel 16 into the turbine impeller 6, causing the impeller 6 to rotate. The exhaust gas then flows out of the turbine housing 4 through the exhaust gas outlet 10.

[0019] The compressor housing 5 is provided with an inlet port 9 and a discharge port 11. When the turbine impeller 6 rotates as described above, the compressor impeller 7 rotates in conjunction with the rotating shaft 14, and the rotating compressor impeller 7 draws in ambient air through the inlet port 9. The air passes through the compressor impeller 7 and the spiral flow channel 17 to be compressed and is discharged through the discharge port 11. The compressed air discharged from the discharge port 11 is supplied to the aforementioned internal combustion engine.

[0020] Turbine 2 of turbocharger 1 is described in more detail below. It should be noted that in the following description, the terms "axial direction," "radial direction," and "circumferential direction" simply refer to the direction of the axis of rotation (direction of the axis of rotation H), the radial direction of rotation, and the circumferential direction of rotation of the turbine impeller 6, respectively. It should also be noted that the terms "upstream" and "downstream" refer to the upstream and downstream sides of the exhaust gas in turbine 2. Furthermore, it should be noted that in the direction of the axis of rotation H, a side close to turbine 2 of turbocharger 1 (left side in) is defined. Fig. 1) is, which can simply be referred to as the “turbine side”, and is a side that is close to compressor 3 (right side in Fig. 1) may be referred to as the “compressor side” if this is appropriate.

[0021] The turbine 2 of the turbocharger 1 has a nozzle flow channel 19, which is arranged around the turbine impeller 6 and is configured to connect the spiral flow channel 16 and the turbine impeller 6. The nozzle flow channel 19 has a plurality of movable nozzle vanes 21. The nozzle vanes 21 are arranged at approximately equal intervals on a circumference centered around the axis of rotation H. The individual nozzle vanes 21 rotate synchronously about an axis NX that is parallel to the axis of rotation H. As a result of this rotation of the nozzle vanes 21, each gap between the adjacent nozzle vanes 21 is widened and narrowed, thereby controlling the opening (aperture) of the nozzle flow channel 19.

[0022] The turbine 2 has a variable nozzle unit 20 for driving the nozzle vanes 21. The variable nozzle unit 20 is located inside the turbine housing 4. The variable nozzle unit 20 has the nozzle vanes 21 and two nozzle rings 23, 27, which hold the nozzle vanes 21 axially between them. The two nozzle rings 23, 27 are arranged axially, with nozzle ring 23 being closer to the compressor than nozzle ring 27. Each of the nozzle rings 23, 27 has an annular shape centered around the axis of rotation H and is arranged to circumferentially surround the turbine impeller 6. A region that is delimited in the axial direction between the two nozzle rings 23, 27 forms the nozzle flow channel 19. The nozzle rings 23, 27 are coupled in the axial direction using a plurality of coupling pins 29.By manufacturing the coupling pins 29 with high dimensional accuracy, the nozzle flow channel 19 will have high dimensional accuracy in the axial direction.

[0023] The variable nozzle unit 20 further comprises 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 is designed to transmit a driving force from an external actuator (not shown) to the nozzle vanes 21. The drive mechanism 25 of the variable nozzle unit 20 is described in more detail below with reference to the Fig. 2 and Fig. 3 explained. Fig. Figure 2 shows a perspective exploded view of the variable nozzle unit 20 and a heat shielding plate 41 and a disc spring 43, which are described below. Fig. Figure 3 shows a top view of the variable nozzle unit 20, viewed in the axial direction from the side of the bearing housing 13. The nozzle ring 23 has bearing holes 31, which are designed to penetrate it in the axial direction. A rotating shaft 21a of the respective nozzle vane 21 is rotatably inserted into each bearing hole 31. It should be noted that the nozzle vanes 21 are not necessarily arranged at regular intervals, although the drawing shows an exemplary arrangement of the nozzle vanes 21 at regular intervals around the circumference.

[0024] The drive mechanism 25 has a drive ring 33, nozzle connection plates 35, and a drive connection plate 37. The drive ring 33 has an annular shape extending along a circumference centered around the axis of rotation H and is arranged along a surface of the nozzle ring 23 located on the compressor side. The drive ring 33 is rotatable about the axis of rotation H relative to the nozzle ring 23. The drive ring 33 has engagement sections 33a that engage with individual nozzle connection plates 35, which are provided at predetermined intervals in the circumferential direction.

[0025] There are an equal number of nozzle connection plates 35 and nozzle vanes 21. Each nozzle connection plate 35 is attached to one end of the rotating shaft 21a of each nozzle vane 21 and extends radially outward from that end. More precisely, each rotating shaft 21a of the nozzle vane 21 is inserted into the bearing hole 31, and one end of each rotating shaft 21a projects from the nozzle ring 23 toward the compressor side. The inner circumferential end of each nozzle connection plate 35 is attached to each end of the projecting rotating shaft 21a. The outer circumferential end of each nozzle connection plate 35 engages with each engagement section 33a of the drive ring 33.

[0026] The drive ring 33 is also provided with an input-side engagement section 33b. The input-side engagement section 33b is arranged between a pair of engagement sections 33a. The outer circumferential end of the drive connection plate 37 engages with the input-side engagement section 33b, while the inner circumferential end of the drive connection plate 37 also engages with a drive shaft 39 (see figure). Fig. 3) is connected to an external actuator.

[0027] When the external actuator rotates the drive connection plate 37 about an axis parallel to the axis of rotation H via the drive shaft 39, the outer circumferential end of the drive connection plate 37 presses the input-side engagement section 33b in the circumferential direction. This causes the drive ring 33 to rotate about the axis of rotation H, and the individual engagement sections 33a of the drive ring 33 press the outer circumferential ends of the individual nozzle connection plates 35 in the circumferential direction. The individual nozzle connection plates 35 then rotate about the axis NX, causing the individual nozzle vanes 21, which are fixed to the individual nozzle connection plates 35, to rotate about the axis NX.

[0028] The following describes a setup for positioning the aforementioned variable nozzle unit 20 in the turbine housing 4. As shown in the Fig. 1 and Fig. As shown in Figure 2, a heat shield 41 is provided between the turbine impeller 6 and the bearing housing 13. The heat shield 41 protects against radiant heat from the high-temperature turbine housing 4, thereby preventing a temperature increase in the bearing housing 13. The heat shield 41 has a ring-like shape that surrounds the rotating shaft 14 in the circumferential direction. The heat shield 41 is inserted into the central opening of the nozzle ring 23 from the side of the bearing housing 13.

[0029] The disc spring 43 is held between the heat shield 41 and the bearing housing 13. The rotating shaft 14 is inserted into a hole at the center of the disc spring 43, which positions the disc spring 43 along a conical surface centered around the axis of rotation H, forming the cone axis. One end of the disc spring 43, in the axial direction, is in contact with the bearing housing 13, while the other end is in contact with the heat shield 41. The disc spring 43 generates a repulsive force that expands (stretches) the distance between the bearing housing 13 and the heat shield 41 in the axial direction. The disc spring 43 axially preloads the variable nozzle unit 20 and the heat shield 41 towards the turbine housing 4.

[0030] Fig. Figure 4 shows an enlarged cross-sectional view of an area around the variable nozzle unit 20, which is located in Fig. Figure 1 shows the nozzle ring 23 having a flange 45 projecting towards the outer circumferential side. The turbine housing 4, on the other hand, has a rib (strip) 47 formed within it, which is designed to engage the flange 45. The rib 47 projects from the inner wall surface of the turbine housing 4 towards the inner circumferential side and extends in an annular shape along the circumference centered on the axis of rotation H. The inner diameter of the rib 47 is smaller than the outer diameter of the flange 45, and the flange 45 abuts the rib 47 from the side of the bearing housing 13.

[0031] With this configuration, the variable nozzle unit 20 is biased towards the turbine side by the disc spring 43. This biasing force presses the flange 45 of the nozzle ring 23 against the rib 47. By pressing the flange 45 against the rib 47, the variable nozzle unit 20 is positioned and thus fixed in the axial direction. The variable nozzle unit 20 is also fixed in a plane direction perpendicular to the axial direction with a certain level of fixing force, by means of the frictional force acting between the flange 45 and the rib 47. It should be noted, however, that if a difference in thermal expansion occurs between the variable nozzle unit 20 and the turbine housing 4, this difference can be absorbed by sliding between the flange 45 and the rib 47.

[0032] The positioning of the variable nozzle unit 20 in the circumferential and radial directions is described below. As described above, the variable nozzle unit 20 is also fixed in the plane direction perpendicular to the axial direction with a certain level of fixing force by means of the frictional force acting between the flange 45 and the rib 47 (flange clamp). In a prior art, this type of variable nozzle unit could employ the structure described above in Patent Document 2 as a means of further limiting the circumferential displacement of the variable nozzle unit. The structure described in Patent Document 2 is provided with a limiting pin extending from the bearing housing to the turbine side. A nozzle ring and the variable nozzle unit are provided with a guide groove extending approximately in the radial direction.With the limiting pin inserted into the guide groove, the variable nozzle unit is positioned in the direction in the plane that is perpendicular to the axial direction.

[0033] The following is a case in which the setup of patent document 2, as described above, is adopted in the turbocharger 1. During operation of the turbocharger 1, the load applied by the disc spring 43 (preload section) will decrease if the disc spring 43 deforms under heat or its modulus of elasticity decreases. This would reduce the frictional force between the flange 45 and the rib 47 and would cause a circumferential displacement (rotational displacement about the axis of rotation H) of the variable nozzle unit 20 by exactly the amount of the gap (the clearance) between the limiting pin and the guide notch in the setup described in patent document 2. The circumferential displacement of the variable nozzle unit 20 will lead to a change in the gas flow rate, particularly when the nozzle flow channel 19 is closed.The turbocharger 1 now has a structure as explained below, which enables the suppression of the circumferential displacement of the variable nozzle unit 20 during operation.

[0034] As this is shown in the Fig. As shown in Figures 2 to 4, the nozzle ring 23 has an annular projection 49 formed at the center of one side of the ring on the compressor side, projecting in such a way as to form a shoulder from the circumference towards the compressor side. The drive ring 33 is arranged so that it concentrically surrounds the annular projection 49. An outer circumferential end surface 49a of the annular projection 49, corresponding to the shoulder, forms a cylindrical surface whose diameter is slightly smaller than the inner diameter of the drive ring 33, and which guides the rotation of the drive ring 33.

[0035] A U-shaped notch 51 is formed in the annular projection 49. The U-shaped notch 51 is formed by notching the annular projection 49 over its entire thickness so that it extends radially from the outer circumferential end surface 49a to the inner circumferential side. The U-shaped notch 51 has a pair of inner wall surfaces 51a, 51a that face each other circumferentially. The inner wall surfaces 51a, 51a form flat planes that are parallel to each other.

[0036] A pin 53 extends axially from a side of the bearing housing 13 located on the turbine side to the turbine side. The pin 53 and the U-groove 51 are arranged at the same circumferential position. The pin 53 is a round, rod-like element whose diameter is approximately equal to the gap between the inner wall surfaces 51a (width of the U-groove 51). Alternatively, the diameter of the pin 53 is slightly larger than the gap between the inner wall surfaces 51a. The pin 53 can be a solid pin 53A with a solid circular cross-section, as shown in Fig. 5(a). The pin 53 can alternatively be a spring pin 53B, which has a C-shaped cross-section in which part of the ring is missing, as shown in Fig. 5(b) is shown. The pin 53 can alternatively be a winding pin 53C formed from an element wound in a plurality of turns, as shown in Fig. 5(c) is shown.

[0037] A base end of the pin 53 is press-fitted into the bearing housing 13. A distal end 53p of the pin 53 is inserted into the U-shaped groove 51 (pin insertion section) and is held circumferentially between the inner wall surfaces 51a. This configuration positions the variable nozzle unit 20 circumferentially with respect to the bearing housing 13, supported by the pin 53. A radial gap exists between the pin 53 and the bottom of the U-shaped groove 51. Contact points of the pin 53 with the inner wall surfaces 51a, 51a are located at mid-sections in the radial direction of the inner wall surfaces 51a, 51a. That is, the inner wall surfaces 51a, 51a, which are parallel to each other, extend from a position on the inner circumferential side relative to the contact points with the pin 53 to a position on the outer circumferential side (outer circumferential end surface 49a).

[0038] More precisely, the distal end 53p of the pin 53 is press-fitted into the U-groove 51. This means that the pin 53 is tightly fitted without any play between the inner wall surfaces 51a in the circumferential direction, and is therefore fixed to the U-groove 51 under the surface pressure applied circumferentially by the inner wall surfaces 51a, 51a. Furthermore, since a gap exists between the pin 53 and the bottom of the U-groove 51 in the radial direction, as described above, the pin 53 can be displaced radially within the U-groove 51 against the frictional force exerted by the inner wall surfaces 51a, 51a, which is attributed to the surface pressure.

[0039] As this is shown in the Fig. 2 and Fig. As shown in Figure 3, the turbocharger 1 has two pairs of pin 53 and U-groove 51; in other words, it has the engagement sections 50, where the pin 53 and the U-groove 51 engage, at two locations, as described above. It should be noted that Fig. 1 does not show the intervention section 50.

[0040] The operating processes and effects of the turbocharger 1, which is equipped with the aforementioned U-shaped groove 51 and the pin 53, are described below. In the turbocharger 1, the circumferential displacement of the variable nozzle unit 20 is limited by the insertion of the pin 53, which extends from the bearing housing 13 into the U-shaped groove 51 of the variable nozzle unit 20. The distal end 53p of the pin 53 now sits in an interference fit in the U-shaped groove 51, as described above, thereby fixing the pin 53 under the surface pressure applied circumferentially by the inner wall surfaces 51a, 51b. Therefore, there is no circumferential gap (circumferential clearance) between the pin 53 and the U-shaped groove 51, so the variable nozzle unit 20 hardly causes the circumferential displacement that would otherwise be attributed to such a gap.Consequently, the variable nozzle unit 20 is prevented from being displaced in the circumferential direction during operation, so that the turbocharger 1 can avoid a change in the exhaust gas flow rate into the nozzle flow channel 19.

[0041] A case is assumed in which a circular hole, into which the pin 53 is press-fitted, is provided at the location of the U-groove 51, with the variable nozzle unit 20 also being limited in the radial direction by the pin 53. Accordingly, any difference in thermal expansion between the variable nozzle unit 20 and the bearing housing 13, if it occurs, would cause thermal deformation of the variable nozzle unit 20, centered around the engagement section 50, such that a neck section of the nozzle flow channel 19 would deform, thereby causing a change in the flow rate of the exhaust gas in the nozzle flow channel 19. In contrast, as a result of the application of the U-groove 51, the pin 53 is enabled to move in the U-groove 51 in the radial direction against the frictional force with the inner wall surfaces 51a, 51a.The aforementioned difference in thermal expansion is therefore absorbed, and this successfully avoids a change in the exhaust gas flow rate in the nozzle flow channel 19 during operation.

[0042] Furthermore, if a solid pin 53A, see. Fig. 5(a), when the pin 53 is used, this is preferred in view of the higher strength of the pin 53 compared to a spring pin 53B, see. Fig. 5(b), or a winding pin 53C, see. Fig. 5(c).

[0043] The following discusses the interference fit of the pin 53 in the U-groove 51. An interference fit, when high, means that the frictional force between the pin 53 and the inner wall surfaces 51a, 51a is high, and this tends to increase wear on the pin 53 or the inner wall surfaces 51a, 51a as the pin 53 moves in the U-groove 51 against the frictional force. The wear on the pin 53 or the inner wall surfaces 51a, 51a would create a circumferential gap between the pin 53 and the inner wall surfaces 51a, 51a, and this would potentially cause circumferential play.

[0044] In an effort to address this problem, the spring pin 53B or the winding pin 53C is introduced as an element whose dimension is elastically variable in the direction in which the inner wall surfaces 51a, 51a are opposed (circumferential direction). In particular, the winding pin 53C is an element whose outer diameter is elastically variable. Consequently, the spring pin 53B or the winding pin 53C necessitates that the press-fit load for press-fitting into the U-groove 51 be relatively lower than that required by the solid pin 53A. Therefore, the use of the spring pin 53B or the winding pin 53C will result in a relatively low frictional force between the pin 53 and the inner wall surfaces 51a, 51a, thus suppressing the aforementioned wear of the pin 53 or the inner wall surfaces 51a, 51a.Furthermore, even if the pin 53 or the inner wall surfaces 51a, 51a should wear out, the pin 53 will elastically expand its diameter to reduce the circumferential gap (circumferential space) that is attributed to wear, thereby avoiding the circumferential space.

[0045] The press fit load of the pin 53 in the U-groove 51, if large, will increase the frictional force between the pin 53 and the inner wall surfaces 51a, 51a in the axial direction. This axial frictional force will impede the preload force of the disc spring 43, which preloads the variable nozzle unit 20 in the axial direction, and weaken the force with which the flange 45 is pressed against the rib 47, thus reducing the frictional force between the flange 45 and the rib 47. To keep the preload force consistently greater than the axial frictional force between the pin 53 and the inner wall surfaces 51a, 51a, the disc spring 43 must be designed to withstand high loads and tight tolerances, which impairs the feasibility of the design.

[0046] In an effort to address this problem, the use of the spring pin 53B or the winding pin 53C will result in a frictional force with the inner wall surfaces 51a, 51a in the axial direction that is relatively lower than that caused by the solid pin 53A. This successfully avoids the aforementioned restriction of the preload force of the disc spring 43 in the axial direction. This mitigates the aforementioned load or tolerance of the disc spring 53 and improves its feasibility in the design. In this respect, the use of the spring pin 53B or the winding pin 53C is preferred.

[0047] The use of the spring pin 53B or the winding pin 53C requires only a relatively low press fit of the pin 53 into the U-groove 51, thus improving the assembleability of the engagement section 50. It should be noted that when the pin 53 is referred to as the spring pin 53B, its strength and other properties will depend on its orientation, requiring adjustment during assembly. In contrast, when the winding pin 53C is referred to, it has a high degree of strength and other properties and requires less adjustment of its orientation during assembly, thus improving assembleability.

[0048] The embodiments of the present disclosure are described above, and the present disclosure is not limited to the embodiments mentioned above and can be modified without changing the main points described in the individual claims. The possible configurations of the individual embodiments can be suitably combined for the purpose of application.

[0049] For example, as this can be seen in Fig. As shown in Figure 6(a), the annular projection 49 of the nozzle ring 23 may be provided with an elongated hole 61, into which the distal end 53p of the pin 53 is press-fitted, instead of the U-shaped notch 51. The elongated hole 61 extends radially and has a pair of inner wall surfaces 51a, 51a in a similar manner to the U-shaped notch 51. Furthermore, as shown, for example, in Fig.As shown in Figure 6(b), the annular projection 49 of the nozzle ring 23 is provided with a slot 65, into which the distal end 53p of the pin 53 is pressed by interference fit, instead of the U-shaped notch 51. The slot 65 extends over the entire width of the annular projection 49 in the radial direction and has a pair of inner wall surfaces 51a, 51a in a similar manner to the U-shaped notch 51.

[0050] It should also be noted that, although the aforementioned embodiments deal with cases in which two engagement sections 50 per variable nozzle unit 20 were provided, it is sufficient that at least one engagement section 50 per variable nozzle unit 20 is provided, or alternatively, that three or more engagement sections 50 per variable nozzle unit 20 may be provided. Reference symbol list 1 variable capacity turbocharger H axis of rotation 4 turbine housings 6 Turbine wheel 13 bearing housings 19 Nozzle flow channel 21 nozzle blades 20 variable nozzle unit 25 Drive mechanism 43 Disc spring (preload section) 45 flange 47 rib (flange barrel) 51 U-notch (pin insertion section) 53, 53A, 5BB, 53C pin 53C winding pin 53p distal end 61 Slotted hole (pin insertion section) 65 Notch (pin insertion section) QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2013-68153

[0002] WO 2021 / 246294

[0002]

Claims

[1] Variable capacity turbocharger with: a turbine housing that accommodates a turbine impeller; a variable nozzle unit with a nozzle vane arranged in a nozzle flow channel provided around the turbine impeller in the turbine housing, and a drive mechanism designed to drive the nozzle vane; a pre-tensioning section designed to pre-tension the variable nozzle unit in one direction of a rotational axis of the turbine impeller so that it is pressed against a section of the turbine housing; a pin extending from a bearing housing that accommodates a bearing of the turbine impeller; and a pin insertion section provided on the variable nozzle unit which allows the insertion of a distal end of the pin, wherein the pin insertion section has a pair of inner wall surfaces designed as parallel flat planes intersecting the circumferential direction of rotation of the turbine impeller, and which hold the distal end of the pin between them in the circumferential direction of rotation, and the distal end of the pin is press-fitted between the inner wall surfaces. [2] Variable capacity turbocharger according to claim 1, wherein the pin insertion section is a notch or elongated hole extending in a direction intersecting the circumferential direction of rotation. [3] Variable capacity turbocharger according to claim 1, wherein the pin is an element whose dimension is elastically variable in the direction in which the inner wall surfaces are opposite each other. [4] Variable capacity turbocharger according to claim 1, wherein the pin is a winding pin whose outer diameter is elastically variable.

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