Variable displacement turbocharger and method for assembling variable displacement turbocharger

Abstract

A variable displacement turbocharger is provided with: a turbine wheel; a variable nozzle device; a first housing having a scroll flow path; a second housing that forms a housing space for housing the turbine wheel and the variable nozzle device between the first housing and the second housing, and that has a through-hole that communicates the housing space with the outside of the second housing; and a driving force transmission device configured to transmit driving force from an actuator disposed outside the second housing to the variable nozzle device, the driving force transmission device including: a control arm configured to control the variable nozzle device; a second housing having an engagement portion that engages with a driving force input portion of the variable nozzle device in the accommodation space and a rotating shaft portion that is inserted through the through hole and partially protrudes to the outside of the second housing; and a lever disposed outside the second housing and having a fixed portion fixed to the rotating shaft portion of the control arm by engagement.

Description

TECHNICAL FIELD

[0001] The present application relates to a variable capacity type turbocharger and a method for assembling a variable capacity type turbocharger. BACKGROUND

[0002] As a turbocharger (supercharger) that supercharges intake air of an internal combustion engine (engine) using exhaust energy of the internal combustion engine, a turbocharger provided with a variable capacity turbine including a variable nozzle device that changes a blade angle of nozzle vanes is known (for example, refer to Patent Literature 1). In the variable capacity turbine, a plurality of nozzle vanes are arranged in an exhaust flow path for delivering exhaust gas from a scroll flow path of the turbine to a turbine wheel in a circumferential direction of the turbine wheel, and by changing the blade angle of the nozzle vanes from the outside by an actuator, it is possible to adjust a flow path cross-sectional area (flow path between adjacent nozzle vanes) of the exhaust flow path. The variable capacity turbine changes a flow rate or pressure of exhaust gas guided to the turbine wheel by adjusting the flow path cross-sectional area of the exhaust flow path, thereby improving a supercharging effect.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: US Patent No. 8684678 Specification SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] However, in the drive force transmission device that transmits drive force from the above-described actuator to the nozzle vanes, as shown in FIG. 1, a rotating shaft portion that penetrates the inside and outside of the housing and a engagement plate that transmits drive force to the variable nozzle device inside the housing are fixed by welding. In this case, it is difficult to absorb errors of each constituent component that constitutes the variable nozzle device or the drive force transmission device or assembly errors generated when each constituent component is assembled, and it is necessary to take into account generation of these errors to design the variable nozzle device or the drive force transmission device of the turbocharger, so that the degree of freedom of their design is reduced, and the range of operation on the design of the variable nozzle device can be narrowed. Figure 5

[0008] In view of the above, an object of at least one embodiment of the present application is to provide a variable capacity type turbocharger and a method for assembling a variable capacity type turbocharger that can suppress narrowing of the range of operation of a variable nozzle device.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] ​At least one embodiment of the present application relates to a variable capacity turbocharger comprising:

[0011] A turbine wheel;

[0012] A first housing having a scroll flow path;

[0013] A variable nozzle device configured to form a gas flow path from the scroll flow path toward the turbine wheel and adjust a flow direction of gas flowing through the gas flow path;

[0014] A second housing coupled to the first housing, a housing space in which the turbine wheel and the variable nozzle device are housed being formed between the first housing and the second housing, and the second housing having a through hole that communicates the housing space with an outside of the second housing; and

[0015] A drive force transmission device configured to transmit a drive force from a driver disposed outside the second housing to the variable nozzle device,

[0016] The drive force transmission device includes:

[0017] A control arm having an engagement portion that engages with a drive force input portion of the variable nozzle device in the housing space and a rotation shaft portion that protrudes to the outside of the second housing by passing through the through hole; and

[0018] A control lever disposed outside the second housing and having a fixed portion that is fixed to the rotation shaft portion of the control arm by engagement.

[0019] A method of assembling a variable capacity turbocharger according to at least one embodiment of the present application,

[0020] The variable capacity turbocharger comprises:

[0021] A turbine wheel;

[0022] A first housing having a scroll flow path;

[0023] A variable nozzle device configured to form a gas flow path from the scroll flow path toward the turbine wheel and adjust a flow direction of gas flowing through the gas flow path;

[0024] A second housing coupled to the first housing, a housing space in which the turbine wheel and the variable nozzle device are housed being formed between the first housing and the second housing, and the second housing having a through hole that communicates the housing space with an outside of the second housing; and

[0025] A drive force transmission device configured to transmit a drive force from a driver disposed outside the second housing to the variable nozzle device,

[0026] The drive force transmission device includes:

[0027] a control arm having an engagement portion that engages with a drive force input portion of the variable nozzle device in the accommodation space and a rotation shaft portion that is inserted through the through hole and protrudes partially to the outside of the second housing; and

[0028] a control lever that is disposed outside the second housing and has a fixed portion that is fixed to the rotation shaft portion of the control arm by engagement.

[0029] The assembly method of the variable displacement turbocharger includes:

[0030] a control arm insertion step of inserting the rotation shaft portion of the control arm through the through hole and protruding a portion thereof to the outside of the second housing;

[0031] a control arm engagement step of engaging the engagement portion of the control arm with the drive force input portion of the variable nozzle device after the control arm insertion step;

[0032] a housing connection step of connecting the first housing and the second housing after the control arm engagement step; and

[0033] a control lever fixing step of fixing the fixed portion of the control lever to the rotation shaft portion of the control arm by engagement after the housing connection step.

[0034] Inventive Effects

[0035] According to at least one embodiment of the present application, a variable displacement turbocharger capable of suppressing a reduction in an operation range of a variable nozzle device and an assembly method of a variable displacement turbocharger are provided. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a schematic cross-sectional view along an axis of a variable displacement turbocharger according to an embodiment of the present application.

[0037] Figure 2 is a schematic view from an axial side of a variable nozzle device and a drive force transmission device of a variable displacement turbocharger according to an embodiment of the present application.

[0038] Figure 3 is a schematic cross-sectional view along an axis of a vicinity of a drive force transmission device of a variable displacement turbocharger according to an embodiment of the present application.

[0039] Figure 4 is a flowchart showing an example of an assembly method of a variable displacement turbocharger according to an embodiment of the present application.

[0040] Figure 5 It is a schematic cross-sectional view along the axis of the vicinity of a driving force transmission device of a variable geometry turbocharger according to a comparative example.

[0041] Figure 6 It is a schematic cross-sectional view taken along the axis of the vicinity of a driving force transmission device of a variable geometry turbocharger according to an embodiment of the present invention.

[0042] Figure 7 It is a schematic cross-sectional view taken along the axis of the vicinity of a driving force transmission device of a variable geometry turbocharger according to an embodiment of the present invention. DETAILED DESCRIPTION

[0043] Several embodiments of the present invention are described below with reference to the accompanying drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention and are merely illustrative examples.

[0044] (Turbocharger)

[0045] Figure 1 1 is a schematic cross-sectional view of a variable geometry turbocharger 1 according to an embodiment of the present invention, taken along the axis LA. The variable geometry turbocharger 1 according to the present invention can be applied to turbochargers (superchargers) for automobiles, ships, or industrial applications (e.g., land power generation). Figure 1 As shown, the turbocharger 1 according to several embodiments includes at least a turbine rotor 20, a first housing (turbine housing) 3, a second housing (bearing housing) 4, a variable nozzle device 5, and a driving force transmission device 6. In the illustrated embodiment, the turbocharger 1 further includes a centrifugal compressor impeller 11, a third housing (compressor housing) 12, and a bearing 13.

[0046] (Turbine rotor)

[0047] like Figure 1 As shown, the turbine rotor 20 includes a turbine shaft 21 extending along the axis LA of the turbine rotor 20 and a turbine impeller 2 provided on one side (right side in the figure) of the turbine shaft 21. The compressor impeller 11 is mounted on the other side (left side in the figure) of the turbine shaft 21.

[0048] (Bearing, cartridge)

[0049] The bearing 13 is configured to be housed in the second housing 4 between the compressor impeller 11 and the turbine impeller 2 and to support the turbine shaft 21 so as to be rotatable. The second housing 4 has a bearing support portion 14 that supports the bearing 13 from the above-described radially outer side. In the present application, components on which the turbine rotor 20, the compressor impeller 11, and the bearing 13 are mounted on the second housing 4 of the turbocharger 1 are defined as a core subassembly.

[0050] Hereinafter, a direction in which the axis LA of the turbine rotor 20 extends is defined as an axial direction of the turbine rotor 20, a direction orthogonal to the axial direction LA is defined as a radial direction of the turbine rotor 20, and a circumferential direction around the axis LA is defined as a circumferential direction of the turbine rotor 20. In the present application, the axial direction, the radial direction, and the circumferential direction of the turbine rotor 20 are sometimes simply referred to as the axial direction, the radial direction, and the circumferential direction, respectively. In the axial direction of the turbine rotor 20, a side on which the turbine impeller 2 is located with respect to the compressor impeller 11 (a right side in the drawing, hereinafter, referred to as a front side) is defined as a front side, and a side on which the compressor impeller 11 is located with respect to the turbine impeller 2 (a side opposite to the above-described front side, a left side in the drawing, hereinafter, referred to as a rear side). In addition, "in a certain direction" in the present application includes not only a certain direction but also a direction inclined within a range of ±15° with respect to a certain direction. Figure 1 Figure 1 In the axial direction of the turbine rotor 20, a side on which the turbine impeller 2 is located with respect to the compressor impeller 11 (a right side in the drawing, hereinafter, referred to as a front side) is defined as a front side, and a side on which the compressor impeller 11 is located with respect to the turbine impeller 2 (a side opposite to the above-described front side, a left side in the drawing, hereinafter, referred to as a rear side). In addition, "in a certain direction" in the present application includes not only a certain direction but also a direction inclined within a range of ±15° with respect to a certain direction.

[0051] (Turbine Impeller)

[0052] The turbine impeller 2 includes a hub 22 having a substantially truncated cone shape and a plurality of turbine blades 23 provided on an outer circumferential surface of the hub 22. The plurality of turbine blades 23 are respectively arranged at intervals from each other in the circumferential direction around the axis LA. The turbine impeller 2 is provided so as to be rotatable integrally with the turbine shaft 21 with the axis LA as a center. The turbine impeller 2 is configured to guide exhaust gas introduced from the radially outer side of the turbine impeller 2 toward the above-described front side in the axial direction of the turbine impeller 2. In the illustrated embodiment, the turbine impeller 2 is configured by an open-type compressor impeller that does not include a ring-shaped member that surrounds the outer circumferences of the plurality of turbine blades 23.

[0053] (Compressor Impeller)

[0054] The compressor impeller 11 includes a hub 111 having a substantially truncated cone shape and a plurality of compressor blades 112 provided on an outer circumferential surface of the hub 111. The plurality of compressor blades 112 are respectively arranged at intervals from each other in the circumferential direction around the axis LA. The compressor impeller 11 is mounted so as to be rotatable integrally with the turbine shaft 21 with the axis LA as a center. The compressor impeller 11 is configured to guide gas that is a combustion gas (for example, air) introduced from the above-described rear side in the axial direction of the compressor impeller 11 and participates in combustion in an internal combustion engine (engine) not shown as an oxidizer toward the radially outer side of the compressor impeller 11. In the illustrated embodiment, the compressor impeller 11 is configured by an open-type compressor impeller that does not include a ring-shaped member that surrounds the outer circumferences of the plurality of compressor blades 112.​

[0055] (First housing, third housing)

[0056] The first housing 3 is coupled to the second housing 4 and configured to house the turbine wheel 2 therebetween so as to be rotatable. The third housing 12 is coupled to the second housing 4 and configured to house the compressor wheel 11 therebetween so as to be rotatable. The second housing 4 is disposed between the first housing 3 and the third housing 12 and coupled to the first housing 3 and the third housing 12, respectively, for example, via fastening members (not shown) such as bolts.

[0057] The first housing 3 is formed with a scroll flow path 31 for guiding exhaust gas discharged from the above-described internal combustion engine to the turbine wheel 2 and an exhaust gas discharge flow path 32 for discharging exhaust gas that has passed through the turbine wheel 2 to the outside of the first housing 3 (the turbocharger 1). In other words, the first housing 3 has the scroll flow path 31 and the exhaust gas discharge flow path 32. The scroll flow path 31 is configured by a scroll-shaped flow path that is provided on the radially outer side of the turbine wheel 2 in a manner so as to surround the periphery of the turbine wheel 2 and extends along the above-described circumferential direction. The exhaust gas discharge flow path 32 extends toward the front side in the above-described axial direction.

[0058] The second housing 4 and the first housing 3 are formed with a housing space 33 that houses the turbine wheel 2 and the variable nozzle device 5 therebetween. The above-described housing space 33 that links the scroll flow path 31 and the exhaust gas discharge flow path 32 is formed by the coupling of the first housing 3 and the second housing 4. The turbine wheel 2 and the variable nozzle device 5 are disposed in the housing space 33 formed on the radially inner side than the scroll flow path 31.

[0059] The variable nozzle device 5 is configured to form a gas flow path 33A that extends from the scroll flow path 31 toward the turbine wheel 2 and adjust the flow direction of gas that flows through the gas flow path 33A. The gas flow path 33A is provided between the scroll flow path 31 and the turbine wheel 2 in the radial direction of the turbine wheel 2 in a manner so as to surround the radially outer side of the turbine wheel 2. The gas flow path 33A is a part of the housing space 33 and formed at a position on the outer circumferential side than the housing portion that houses the turbine wheel 2 in the housing space 33. Exhaust gas is guided from the scroll flow path 31 to the turbine wheel 2 via the gas flow path 33A.

[0060] Exhaust gas discharged from the above-described internal combustion engine due to combustion in the internal combustion engine is guided to the turbine wheel 2 via the scroll flow path 31 and the gas flow path 33A. The turbocharger 1 is configured to rotate the turbine wheel 2 by the energy of the exhaust gas guided to the turbine wheel 2. The compressor wheel 11 is coupled to the turbine wheel 2 on the same axis via the turbine shaft 21 and thus rotates and is driven around the axis LA in conjunction with the rotation of the turbine wheel 2. The exhaust gas that rotates and drives the turbine wheel 2 is discharged to the outside of the first housing 3 via the exhaust gas discharge flow path 32.

[0061] The turbocharger 1 is configured to intake air (combustion gas) into the inside of the third housing 12 and compress the air by rotating and driving the compressor impeller 11 around the axis LA to deliver the compressed air to the above-described internal combustion engine.

[0062] A gas introduction flow path 121 and a scroll flow path 122 are formed on the third housing 12. The gas introduction flow path 121 is a flow path for introducing air (combustion gas) from the outside of the third housing 12 and guiding the introduced air to the compressor impeller 11. The gas introduction flow path 121 extends along the axial direction of the compressor impeller 11, and is provided at a position further on the above-described axial direction side (rear side) than the compressor impeller 11. By rotating and driving the compressor impeller 11, air is introduced from the outside of the third housing 12 to the gas introduction flow path 121, and the introduced air flows in the gas introduction flow path 121 toward the compressor impeller 11 to be guided to the compressor impeller 11.

[0063] The scroll flow path 122 is composed of a scroll-shaped flow path that is provided on the radial direction outer side of the compressor impeller 11 in a manner of surrounding the periphery of the compressor impeller 11, and extends along the circumferential direction of the compressor impeller 11. Air that passes through the compressor impeller 11 and is compressed by the compressor impeller 11 is guided to the scroll flow path 122. The compressed air that passes through the scroll flow path 122 is guided to the above-described internal combustion engine.

[0064] (VARIABLE NOZZLE DEVICE)

[0065] Figure 2 is a schematic view of the variable nozzle device 5 and the driving force transmission device 6 of the turbocharger 1 according to an embodiment of the present application, as viewed from the above-described axial direction side (rear side). In several embodiments, as shown in Figs. 1 to 3, the variable nozzle device 5 includes a driving force input portion 51, a nozzle mounting member 52, a plurality of nozzle vanes 53, a driving ring 54, and a plurality of lever plates 55. Figure 1 and Figure 2 The variable nozzle device 5 includes a driving force input portion 51, a nozzle mounting member 52, a plurality of nozzle vanes 53, a driving ring 54, and a plurality of lever plates 55.

[0066] (NOZZLE MOUNTING MEMBER)

[0067] A gas flow path 33A is formed between the nozzle mounting member 52 and the other member 10. The nozzle mounting member 52 is located at a position further on the rear side than the gas flow path 33A, and the other member 10 is located at a position further on the front side than the gas flow path 33A. Hereinafter, the direction in which the axis LB of the nozzle mounting member 52 (variable nozzle device 5) extends is set as the axial direction of the variable nozzle device 5, the direction orthogonal to the axis LB is set as the radial direction of the variable nozzle device 5, and the circumferential direction around the axis LB is set as the circumferential direction of the variable nozzle device 5. The extending direction of the axis LB is the direction along the extending direction of the axis LA.

[0068] The nozzle mounting member 52 is provided on the outer peripheral side of the turbine wheel 2 and includes a ring-shaped plate extending in the circumferential direction of the variable nozzle device 5. The nozzle mounting member 52 has a ring-shaped mounting member side flow path surface 521 facing the gas flow path 33A on the one side in the thickness direction of the nozzle mounting member 52, i.e., the front side. The nozzle mounting member 52 has a ring-shaped mounting member side back surface 522 on the other side in the thickness direction of the nozzle mounting member 52, i.e., the rear side.

[0069] (Nozzle plate)

[0070] In the illustrated embodiment, as shown in Figure 1 , the variable nozzle device 5 further includes a nozzle plate 56 as the other member 10. The nozzle plate 56 includes a ring-shaped plate extending in the circumferential direction of the variable nozzle device 5. The nozzle plate 56 has a ring-shaped plate side flow path surface 561 facing the gas flow path 33A on the one side in the thickness direction of the nozzle plate 56, i.e., the rear side. The plate side flow path surface 561 is arranged facing the mounting member side flow path surface 521 with a gap therebetween, and the gas flow path 33A is formed between the plate side flow path surface 561 and the mounting member side flow path surface 521. In other embodiments, the variable nozzle device 5 can not include the nozzle plate 56, and the first case 3 as the other member 10 can have a flow path surface that forms the gas flow path 33A with the mounting member side flow path surface 521.

[0071] (Nozzle support member)

[0072] In the illustrated embodiment, as shown in Figure 1 , the variable nozzle device 5 further includes a plurality of nozzle support members 57 that support the nozzle mounting member 52 and the nozzle plate 56 in a mutually separated state. The plurality of nozzle support members 57 are respectively arranged at positions more radially outward of the variable nozzle device 5 than the plurality of nozzle vanes 53.

[0073] The mounting member side back surface 522 of the nozzle mounting member 52 forms a rear side space 33B between the first case 3 and the second case 4. The rear side space 33B is a part of the accommodation space 33 and is formed on the side opposite the gas flow path 33A with the nozzle mounting member 52 interposed therebetween.

[0074] (Nozzle vane)

[0075] The plurality of nozzle vanes 53 are respectively arranged on the gas flow path 33A and are supported to the nozzle mounting member 52 in a manner capable of rotating about respective rotation centers RC. The plurality of nozzle vanes 53 are respectively arranged with a gap interposed therebetween in the circumferential direction of the variable nozzle device 5.

[0076] (Drive ring)

[0077] The drive ring 54 is disposed in the rear side space 33B and has the drive force input portion 51 mounted thereto. The drive ring 54 is configured to be rotatable about the axis LB relative to the nozzle mount 52 by the drive force transmitted through the drive force input portion 51. The drive ring 54 includes a ring-shaped body extending in the circumferential direction of the variable nozzle device 5. The drive ring 54 has the fitting portions 541 at a plurality of positions in the circumferential direction of the variable nozzle device 5.

[0078] (lever plate)

[0079] The variable nozzle device 5 has the same number of lever plates 55 as the nozzle vanes 53. Each of the plurality of lever plates 55 includes a vane fixing portion 551 fixed to one of the plurality of nozzle vanes 53 and a fitting portion 552 fitted to one of the plurality of fitting portions 541 of the drive ring 54. Each of the plurality of lever plates 55 is disposed in the rear side space 33B, with the vane fixing portion 551 provided on one side of the lever plate 55 fixed to the corresponding nozzle vane 53 and the fitting portion 552 provided on the other side of the lever plate 55 fitted to the corresponding fitting portion 541. Each of the plurality of lever plates 55 is configured to change the vane angle of the nozzle vane 53 fixed to the vane fixing portion 551 in conjunction with the rotation of the drive ring 54 about the axis LB.

[0080] In Figure 2 In the embodiment shown in the drawing, each of the plurality of fitting portions 541 includes a groove portion formed in the outer peripheral portion of the drive ring 54, and each of the plurality of fitting portions 552 is received inside the corresponding groove portion and loosely fitted to the groove portion.

[0081] The nozzle mount 52 has a plurality of through holes 523 that penetrate the mount side flow passage surface 521 and the mount side back surface 522. The plurality of through holes 523 are disposed at intervals in the circumferential direction of the variable nozzle device 5. The nozzle mount 52 has the same number of through holes 523 as the nozzle vanes 53. Each of the plurality of lever plates 55 is inserted through the corresponding through hole 523.

[0082] If the drive ring 54 is rotated to one side in the circumferential direction of the variable nozzle device 5, the nozzle vanes 53 adjacent to each other in the circumferential direction are moved (rotated) in directions away from each other, so that the flow passage cross-sectional area of the gas flow passage 33A between the nozzle vanes 53 becomes larger. Also, if the drive ring 54 is rotated to the other side in the circumferential direction of the variable nozzle device 5, the nozzle vanes 53 adjacent to each other in the circumferential direction are moved (rotated) in directions toward each other, so that the flow passage cross-sectional area of the gas flow passage 33A between the nozzle vanes 53 becomes smaller.

[0083] The variable nozzle device 5 changes the blade angles of the plurality of nozzle vanes 53 by rotating the plurality of nozzle vanes 53 about respective centers of rotation RC by transmitting a driving force from the driver 60 to the plurality of nozzle vanes 53 via the driving ring 54 and the plurality of lever plates 55, thereby being able to adjust the flow passage cross-sectional area of the gas flow passage 33A. The turbocharger 1 increases and decreases the flow passage cross-sectional area of the gas flow passage 33A by the variable nozzle device 5, thereby being able to change the flow rate or pressure (inlet pressure) of the exhaust gas guided to the turbine wheel 2, the flow rate or pressure (outlet pressure) of the exhaust gas passing through the turbine wheel 2, thereby being able to control the supercharging pressure of the turbocharger 1.

[0084] (Driving force transmission device)

[0085] Figure 3 is a schematic cross-sectional view along the axis LA in the vicinity of the driving force transmission device 6 of the turbocharger 1 according to an embodiment of the present application. As shown in Figure 1 , the driving force transmission device 6 is configured to transmit a driving force from the driver 60 disposed outside the second housing 4 to the variable nozzle device 5. The driving force transmission device 6 includes at least a control arm 7 and a control lever 8.

[0086] (Control arm)

[0087] As shown in Figure 1 and Figure 2 , the control arm 7 has an engagement portion 71 engaged with a driving force input portion 51 of the variable nozzle device 5 in the above rear side space 33B (accommodation space 33) and a rotation shaft portion 72 protruding to the outside of the second housing 4 by being inserted through a through-hole 41 extending through the inside and outside of the second housing 4.

[0088] In the illustrated embodiment, as shown in Figure 1 , it includes a second housing side linking portion 42 extending from the front side end portion of the second housing 4 toward the above radial outside along the above radial direction and linked to the first housing 3, and a third housing side linking portion 45 extending from the rear side end portion of the second housing 4 toward the above radial outside along the above radial direction and linked to the third housing 12.

[0089] The 2nd housing side connecting portion 42 has one face 43 facing the rearward side space 33B on one side in the thickness direction of the 2nd housing side connecting portion 42, and has another face 44 facing the outside space 47 of the 2nd housing 4 on the other side in the thickness direction of the 2nd housing side connecting portion 42. The 3rd housing side connecting portion 45 has one face 46 facing the outside space 47 of the 2nd housing 4 on one side in the thickness direction of the 3rd housing side connecting portion 45. The one face 46 faces the other face 44 across the outside space 47. The through-hole 41 extends in a direction parallel to the above-mentioned axial direction, and penetrates the one face 43 and the other face 44 of the 2nd housing side connecting portion 42. The rearward side space 33B communicates with the outside space 47 via the through-hole 41.

[0090] The rotation shaft portion 72 is formed in a bar shape extending along an axis LD of the rotation shaft portion 72, and has a coupling plate 73 having the coupling portion 71 fixed on one side thereof in the extending direction. The coupling plate 73 extends in a direction intersecting the axis LD (orthogonal in the illustrated example), and has the coupling portion 71 formed on the side opposite to the side on which the rotation shaft portion 72 is fixed. The rotation shaft portion 72 is formed integrally with the coupling plate 73. The other side of the rotation shaft portion 72 in the extending direction includes a protruding portion 72A protruding to the outside space 47.

[0091] (CONTROL LEVER)

[0092] The control lever 8 is disposed outside the 2nd housing 4. The control lever 8 has a fixed portion 81 fixed to the protruding portion 72A of the rotation shaft portion 72 by engagement. The control lever 8 has an elongated plate 82 extending in the longitudinal direction, and the fixed portion 81 is fixed to one side of the elongated plate 82 in the longitudinal direction. The fixed portion 81 and the elongated plate 82 are formed integrally. The control lever 8 is fixed to the protruding portion 72A by the fixed portion 81 by engagement, and is rotatable about the axis LD together with the control arm 7.

[0093] The drive force transmission device 6 has a link mechanism that transmits a drive force from the driving portion 601 of the driver 60 to the control lever 8. In the illustrated embodiment, the other side of the elongated plate 82 is linked to one side of a 1st link member 62 in a rotatable manner about an axis LE via a rotation mechanism portion 61 constituted by a link pin or the like. The other side of the 1st link member 62 is linked to the other side of a 2nd link member 64 in a rotatable manner about an axis LF via a rotation mechanism portion 63 constituted by a link pin or the like, and one side of the 2nd link member 64 is fixed to the driving portion 601 of the driver 60.

[0094] (ASSEMBLY METHOD OF TURBOCHARGER)

[0095] Figure 4is a flowchart showing an example of an assembly method 100 of a variable displacement type turbocharger 1 according to an embodiment of the present application. The assembly method 100 of the variable displacement type turbocharger 1 according to the embodiments is an assembly method of the turbocharger 1 described above. As shown in Figure 4 The assembly method 100 of the turbocharger 1 includes at least a control arm insertion step S1, a control arm engagement step S2, a housing connection step S3, and a control lever fixation step S4.

[0096] In the control arm insertion step S1, the rotation shaft portion 72 of the control arm 7 is inserted through the through-hole 41 and a part thereof is projected to the outside of the second housing 4. The control arm insertion step S1 is performed with respect to the above-described core subassembly of the turbocharger 1.

[0097] In the control arm engagement step S2, after the control arm insertion step S1, the engagement portion 71 of the control arm 7 is engaged with the driving force input portion 51 of the variable nozzle device 5. In the control arm engagement step S2, the variable nozzle device 5 is mounted to the above-described core subassembly of the turbocharger 1.

[0098] In the housing connection step S3, after the control arm engagement step S2, the first housing 3 and the second housing 4 are connected. In the control lever fixation step S4, after the housing connection step S3, the fixed portion 81 of the control lever 8 is fixed to the rotation shaft portion 72 of the control arm 7 by joining.

[0099] (Turbocharger according to comparative example)

[0100] Figure 5 is a schematic cross-sectional view along the axis LA of the vicinity of the driving force transmission device 06 of the variable displacement type turbocharger 01 according to the comparative example. As shown in Figure 5 The driving force transmission device 06 includes an engagement plate 07 and a crank member 08. The engagement plate 07 is formed with an engagement portion 071 engaged with the driving force input portion 51 of the variable nozzle device 5 and a through-hole 072. The crank member 08 is integrally formed with a rotation shaft portion 081 inserted through the through-hole 41 and a long plate 082 projected to the outside of the second housing 4 from a part of the rotation shaft portion 081. With respect to the rotation shaft portion 081, one side of the rotation shaft portion 081 is inserted into the through-hole 072, and the rotation shaft portion 081 is fixed to the engagement plate 07 by welding the rotation shaft portion 081 to the engagement plate 07 at a welding portion W3.

[0101] In the turbocharger 01 according to the comparative example, the welding of the rotation shaft portion 081 to the engagement plate 07 cannot be performed after the variable nozzle device 5 and the first housing 3 are mounted to the above-described core subassembly of the turbocharger 1. Therefore, in the turbocharger 01, the variable nozzle device 5 and the first housing 3 are mounted to the above-described core subassembly of the turbocharger 1 after the rotation shaft portion 081 is welded to the engagement plate 07.

[0102] In the turbocharger 1 of the present invention, the control arm 7 and the control rod 8 can be fixed by joining after the variable nozzle device 5 and the first housing 3 are installed in the core assembly of the turbocharger 1. In this case, when the control arm 7 and the control rod 8 are fixed by joining, it is possible to absorb the errors of the various components constituting the variable nozzle device 5 or the driving force transmission device 6 or the assembly errors generated when the various components are assembled. In contrast, in the turbocharger 01 involved in the comparative example, since the errors of the various components or the assembly errors cannot be absorbed, it is necessary to consider these errors in advance when designing the variable nozzle device 5 or the driving force transmission device 06 of the turbocharger 01. As a result, their design freedom is reduced, and the design range of the variable nozzle device 5 may be narrowed.

[0103] Therefore, according to the above-described structure (method), the control arm 7 and the control rod 8 can be fastened by joining after the variable nozzle device 5 and the first housing 3 are mounted on the second housing 4. In this case, the fastening of the control arm 7 and the control rod 8 by joining them can accommodate errors in the various components that make up the variable nozzle device 5 or the driving force transmission device 6, or errors in assembly of the components. Furthermore, according to the above-described structure (method), the design freedom of the variable nozzle device 5 or the driving force transmission device 6 is increased compared to the turbocharger 01 according to the comparative example. This improves the wear tolerance of the variable nozzle device 5 or the driving force transmission device 6, and allows them to be operated by an actuator 60 with a relatively low output power. Furthermore, according to the above-described structure (method), by locating the joint between the control arm 7 and the control rod 8 outside the turbocharger 1 housing (outside space 47), where the temperature is relatively low, the reliability of the turbocharger 1 can be improved compared to a case where the joint is located inside the turbocharger 1 housing (rear space 33B), where the temperature is relatively high.

[0104] like Figure 4 As shown, the turbocharger 1 assembly method 100 according to several embodiments further includes a control arm adjustment step S5 for adjusting the circumferential angle of the rotating shaft portion 72 of the control arm 7. The control arm adjustment step S5 is performed after the housing connection step S3 and before the control rod fixing step S4. In the control arm adjustment step S5, the circumferential angle of the rotating shaft portion 72 is adjusted so that the pressure (inlet pressure) of the exhaust gas introduced into the first housing 3 is set to a predetermined pressure, and the pressure (outlet pressure) of the exhaust gas discharged from the first housing 3 is within a predetermined value or a predetermined range. The circumferential angle of the rotating shaft portion 72 in the control arm adjustment step S5 is adjusted by rotating the protrusion 72A outside the second housing 4.

[0105] The driver 60 is configured to change the operation angle of the lever 8 to an operation angle corresponding to an instruction value inputted from the outside, according to the instruction value. The driver 60 is inputted with a prescribed instruction value, and the operation angle of the lever 8 is set to a prescribed operation angle. In the lever fixing step S4, the above-mentioned inlet pressure is set to a prescribed pressure, and the above-mentioned outlet pressure is set to a prescribed value or a prescribed range, and the control arm 7 and the lever 8 set to the prescribed operation angle are engaged. In this case, when the control arm 7 and the lever 8 are fixed by engagement, it is possible to effectively absorb the error of each component configuring the variable nozzle device 5 or the driving force transmission device 6, or the assembly error generated when each component is assembled.

[0106] Figure 6 and Figure 7 are each a schematic cross-sectional view along the axis in the vicinity of the driving force transmission device 6 of the variable displacement turbocharger 1 according to an embodiment of the present application. In the turbocharger 1 according to the several embodiments, as shown in Figure 3 and Figure 6 , the fixed portion 81 is engaged to the rotating shaft portion 72 by welding or brazing.

[0107] In the embodiment shown in Figure 3 , the fixed portion 81 is engaged to the rotating shaft portion 72 by welding. In the embodiment shown in Figure 3 , the driving force transmission device 6 is provided with a welding portion Wl that fixes the end surface of the fixed portion 81 on the side separated from the penetration hole 41 to the outer peripheral surface of the protruding portion 72A by welding, and a welding portion W2 that fixes the end surface of the fixed portion 81 on the side close to the penetration hole 41 to the outer peripheral surface of the protruding portion 72A by welding. The driving force transmission device 6 can be provided with only one of the welding portion Wl or the welding portion W2.

[0108] In the embodiment shown in Figure 6 , the fixed portion 81 is engaged to the rotating shaft portion 72 by brazing. In the embodiment shown in Figure 6 , the driving force transmission device 6 is provided with a brazing portion BM that fixes the inner surface of the fixed portion 81 to the outer peripheral surface of the protruding portion 72A by brazing through a brazing material.

[0109] According to the above structure, by engaging the fixed portion 81 to the rotating shaft portion 72 by welding or brazing, it is not necessary to separately prepare a fastening member or the like for fastening the fixed portion 81 to the rotating shaft portion 72, and thus it is possible to suppress an increase in the number of components of the variable nozzle device 5 and the driving force transmission device 6.

[0110] In the turbocharger 1 according to the several embodiments, as shown in Figure 7 , the fixed portion 81 is engaged to the rotating shaft portion 72 by press-fitting. InFigure 7 In the illustrated embodiment, the fixed portion 81 that surrounds the rotation shaft portion 72 has a press-fitting region 812 that is deformed by an external force F and press-fitted to the rotation shaft portion 72.

[0111] According to the above-described structure, by press-fitting the fixed portion 81 to the rotation shaft portion 72, a fastening member or the like for fastening the fixed portion 81 to the rotation shaft portion 72 is not required, and thus the number of components of the variable nozzle device 5 and the driving force transmission device 6 can be suppressed from increasing.

[0112] In the turbocharger 1 according to the various embodiments, as shown in Figure 3 , Figure 6 and Figure 7 , the fixed portion 81 includes a cylindrical portion 81A having a circumferential inner surface 811 that surrounds a circumferential outer surface 721 of the rotation shaft portion 72 that protrudes to the outside of the second housing 4. The circumferential outer surface 721 and the circumferential inner surface 811 are formed in a circular shape.

[0113] According to the above-described structure, by providing the fixed portion 81 as the cylindrical portion 81A, the rotation shaft portion 72 is not limited in the circumferential angle when the rotation shaft portion 72 is provided, and thus the assembly of the cylindrical portion 81A and the rotation shaft portion 72 and the adjustment of the circumferential angle are facilitated.

[0114] In the turbocharger 1 according to the various embodiments, as shown in Figure 7 , a screwing groove 811A for screwing the rotation shaft portion 72 of the control arm 7 is formed in the circumferential inner surface 811 of the above-described cylindrical portion 81A. A screwing groove 721A that screws with the screwing groove 811A is formed in the circumferential outer surface 721 of the protruding portion 72A of the rotation shaft portion 72.

[0115] According to the above-described structure, by providing the screwing groove 811A for screwing the rotation shaft portion 72 in the circumferential inner surface 811 of the cylindrical portion 81A, the adjustment of the circumferential angle of the cylindrical portion 81A and the rotation shaft portion 72 is further facilitated. In addition, the screwing grooves 811A, 721A can be formed in the cylindrical portion 81A or the rotation shaft portion 72 as shown in Figure 3 and Figure 6 .

[0116] In the turbocharger 1 according to the various embodiments, as shown in Figure 3 , Figure 6 and Figure 7As shown, the turbocharger 1 further includes a sleeve 9 disposed between the through-hole 41 and the rotation shaft portion 72. The sleeve 9 is pressed into the through-hole 41 before the control arm insertion step S1. The surface roughness (e.g., arithmetic average roughness, maximum height, ten-point average roughness) of the inner surface of the sleeve 9 is smaller than the surface roughness of the inner surface of the through-hole 41.

[0117] According to the above structure, by disposing the sleeve 9 between the through-hole 41 and the rotation shaft portion 72, the shift of the axis LD of the rotation shaft portion 72 can be suppressed, and the frictional loss when the rotation shaft portion 72 rotates can be reduced.

[0118] As shown in Figure 1 and Figure 2 In the turbocharger 1 according to the embodiments, the variable nozzle device 5 includes the nozzle mounting member 52, the plurality of nozzle vanes 53, the drive ring 54 on which the drive force input portion 51 is mounted, and the plurality of lever plates 55. In this case, by transmitting the drive force from the drive force transmission device 6 to the drive force input portion 51 mounted on the drive ring 54, the vane angle of the plurality of nozzle vanes 53 can be changed via the drive ring 54 and the plurality of lever plates 55.

[0119] In the turbocharger 1 according to the embodiments, as shown in Figure 2 the drive force input portion 51 is constituted by a fitting pin 51A mounted on the drive ring 54, and the fitting portion 71 is constituted by a hole or a slot 71A into which the fitting pin 51A is inserted.

[0120] According to the above structure, by rotating the control arm 7 around the axis LD of the rotation shaft portion 72 with the drive force from the driver 60, the fitting pin 51A can be moved around the axis LB of the variable nozzle device 5 through the hole or the slot 71A.

[0121] In the present specification, expressions indicating relative or absolute arrangement such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" indicate not only such arrangement in a strict sense but also a state of relative displacement at an angle or distance within a range in which a same function can be obtained with a tolerance or separation.

[0122] For example, expressions indicating that things are in the same state such as "same", "equal", and "homogeneous" indicate not only the same state in a strict sense but also a state in which a difference within a range in which a same function can be obtained with a tolerance or separation.

[0123] Also, in the present specification, expressions indicating shapes such as quadrangle or cylindrical shape indicate not only geometrically strict shapes such as quadrangle or cylindrical shape but also shapes including concave-convex portions or chamfered portions and the like within a range in which a same effect can be obtained.

[0124] Also, in the present specification, the expressions "comprise", "include" or "have" are not intended to exclude the presence of other constituents.

[0125] The present application is not limited to the above-described embodiments, and includes modes in which the above-described embodiments are modified or modes in which these modes are appropriately combined.

[0126] The contents described in the above-described several embodiments can be understood as follows, for example.

[0127] 1) The variable capacity type turbocharger 1 according to at least one embodiment of the present application includes:

[0128] a turbine wheel 2;

[0129] a first housing 3 having a scroll flow path 31;

[0130] a variable nozzle device 5 configured to form a gas flow path 33A from the scroll flow path 31 toward the turbine wheel 2 and adjust a flow direction of gas flowing through the gas flow path 33A;

[0131] a second housing 4 coupled to the first housing 3, a housing space 33 in which the turbine wheel 2 and the variable nozzle device 5 are housed being formed between the first housing 3 and the second housing 4, and the second housing 4 having a through-hole 41 that communicates the housing space 33 with the outside of the second housing 4; and

[0132] a drive force transmission device 6 configured to transmit a drive force from a driver 60 disposed outside the second housing 4 to the variable nozzle device 5,

[0133] the drive force transmission device 6 includes:

[0134] a control arm 7 having an engagement portion 71 that engages with a drive force input portion 51 of the variable nozzle device 5 in the housing space 33 and a rotation shaft portion 72 that protrudes to the outside of the second housing 4 by passing through the through-hole 41; and

[0135] a control lever 8 disposed outside the second housing 4 and having a fixed portion 81 that is fixed to the rotation shaft portion 72 of the control arm 7 by engagement.

[0136] According to the structure of the above 1), the control arm 7 and the control lever 8 can be fixed by engagement after the variable nozzle device 5 and the first housing 3 are installed in the second housing 4.

[0137] In this case, an error of each constituent component configuring the variable nozzle device 5 or the drive force transmission device 6 or an assembly error generated when the constituent components are assembled can be absorbed when the control arm 7 and the control lever 8 are fixed by engagement.

[0138] And, according to the structure of the above 1), compared with the turbocharger 01 involved in the comparative example, the design freedom of the variable nozzle device 5 or the driving force transmission device 6 can be improved.

[0139] 2) In several embodiments, the variable displacement turbocharger 1 according to the above 1), wherein,

[0140] The fixed portion 81 is joined to the rotating shaft portion 72 by welding or brazing.

[0141] According to the structure of the above 2), by joining the fixed portion 81 and the rotating shaft portion 72 by welding or brazing, a fastening member or the like for fastening the fixed portion 81 and the rotating shaft portion 72 is not required to be prepared separately, so that the increase in the number of components of the variable nozzle device 5 and the driving force transmission device 6 can be suppressed.

[0142] 3) In several embodiments, the variable displacement turbocharger 1 according to the above 1), wherein,

[0143] The fixed portion 81 is joined to the rotating shaft portion 72 by press fitting.

[0144] According to the structure of the above 3), by joining the fixed portion 81 and the rotating shaft portion 72 by press fitting, a fastening member or the like for fastening the fixed portion 81 and the rotating shaft portion 72 is not required to be prepared separately, so that the increase in the number of components of the variable nozzle device 5 and the driving force transmission device 6 can be suppressed.

[0145] 4) In several embodiments, the variable displacement turbocharger 1 according to any one of the above 1) to 3), wherein,

[0146] The fixed portion 81 includes a cylindrical portion 81A having a circumferential inner surface 811 that surrounds the circumferential outer surface 721 of the rotating shaft portion 72 that protrudes to the outside of the second housing 4.

[0147] According to the structure of the above 4), by providing the fixed portion 81 as the cylindrical portion 81A, the assembly of the cylindrical portion 81A and the rotating shaft portion 72 and the adjustment of the circumferential angle become easy without being restricted by the cylindrical portion 81A when the rotating shaft portion 72 is provided at an arbitrary circumferential angle.

[0148] 5) In several embodiments, the variable displacement turbocharger 1 according to the above 4), wherein,

[0149] A screwing groove 811A for screwing the rotating shaft portion 72 of the control arm 7 is formed on the circumferential inner surface 811 of the cylindrical portion 81A.

[0150] According to the structure of the above 5), by providing the screwing groove 811A for screwing the rotating shaft portion 72 on the circumferential inner surface 811 of the cylindrical portion 81A, adjustment of the circumferential angle of the cylindrical portion 81A and the rotating shaft portion 72 becomes easier.

[0151] 6) In some embodiments, the variable displacement turbocharger 1 according to any one of the above 1) to 5) further includes a sleeve 9 disposed between the through hole 41 and the rotating shaft portion 72.

[0152] According to the structure of the above 6), by disposing the sleeve 9 between the through hole 41 and the rotating shaft portion 72, the shift of the axis LD of the rotating shaft portion 72 can be suppressed, and the frictional loss when the rotating shaft portion 72 rotates can be reduced.

[0153] 7) In some embodiments, the variable displacement turbocharger 1 according to any one of the above 1) to 6) wherein,

[0154] The variable nozzle device 5 includes:

[0155] A nozzle mounting member 52 forms the gas flow path 33A with other members 10;

[0156] A plurality of nozzle vanes 53 are rotatably supported on the nozzle mounting member 52;

[0157] A drive ring 54 is provided so as to be rotatable around the axis of the nozzle mounting member 52, has fitting portions 541 at a plurality of portions in the circumferential direction, and the drive force input portion 51 is mounted thereon; and

[0158] A plurality of lever plates 55 each include a vane fixing portion 551 fixed to one of the plurality of nozzle vanes 53 and a fitting portion 552 fitted to one of the plurality of fitting portions 541 of the drive ring 54.

[0159] According to the structure of the above 7), by transmitting the drive force from the drive force transmission device 6 to the drive force input portion 51 mounted on the drive ring 54, the vane angle of the plurality of nozzle vanes 53 can be changed via the drive ring 54 and the plurality of lever plates 55.

[0160] 8) In some embodiments, the variable displacement turbocharger 1 according to the above 7) wherein,

[0161] The drive force input portion 51 of the variable nozzle device 5 is constituted by a fitting pin 51A mounted on the drive ring 54,

[0162] The fitting portion 71 of the control arm 7 is constituted by a hole or a slot 71A into which the fitting pin 51A is inserted.

[0163] According to the structure of 8) described above, by rotating the control arm 7 around the axis of the rotation axis portion 72 by the driving force from the driver 60, the engagement pin 51A can be moved around the axis LB of the variable nozzle device 5 by the insertion hole or slot 71A.

[0164] 9) In the assembly method 100 of the variable capacity type turbocharger 1 according to at least one embodiment of the present application, the variable capacity type turbocharger 1 is provided with:

[0165] a turbine wheel 2;

[0166] a first housing 3 having a scroll flow path 31;

[0167] a variable nozzle device 5 configured to form a gas flow path 33A from the scroll flow path 31 toward the turbine wheel 2 and adjust the flow direction of gas flowing through the gas flow path 33A;

[0168] a second housing 4 coupled to the first housing 3, a housing space 33 in which the turbine wheel 2 and the variable nozzle device 4 are housed being formed between the first housing 3 and the second housing 4, and the second housing 4 having a through hole 41 that communicates the housing space 33 with the outside of the second housing 4; and

[0169] a driving force transmission device 6 configured to transmit a driving force from a driver 60 disposed outside the second housing 4 to the variable nozzle device 5,

[0170] the driving force transmission device 6 includes:

[0171] a control arm 7 having an engagement portion 71 that engages the driving force input portion 51 of the variable nozzle device 5 in the housing space 33 and a rotation axis portion 72 that protrudes partially to the outside of the second housing 4 by passing through the through hole 41; and

[0172] a control lever 8 disposed outside the second housing 4 and having a fixed portion 81 that is fixed to the rotation axis portion 72 of the control arm 7 by engagement,

[0173] the assembly method 100 of the variable capacity type turbocharger 1 includes:

[0174] a control arm insertion step S1 of inserting the rotation axis portion 72 of the control arm 7 into the through hole 41 and protruding a part of the rotation axis portion 72 to the outside of the second housing 4;

[0175] a control arm engagement step S2 of engaging the engagement portion 71 of the control arm 7 to the driving force input portion 51 of the variable nozzle device 5 after the control arm insertion step S1;

[0176] The housing joining step S3 joins the first housing 3 and the second housing 4 after the control arm engaging step S2.

[0177] The control lever fixing step S4 fixes the fixed portion 81 of the control lever 8 to the rotation shaft portion 72 of the control arm 7 by bonding after the housing joining step S3.

[0178] According to the method of 9) described above, the control arm 7 and the control lever 8 can be fixed by bonding after the variable nozzle device 5 and the first housing 3 are installed to the second housing 4.

[0179] In this case, errors of each component constituting the variable nozzle device 5 or the driving force transmission device 6 or assembly errors generated when each component is assembled can be absorbed when the control arm 7 and the control lever 8 are fixed by bonding.

[0180] Further, the turbocharger 1 assembled by the method of 9) described above can improve the design freedom of the variable nozzle device 5 or the driving force transmission device 6 compared to the turbocharger 01 related to the comparative example.

[0181] Explanation of symbols

[0182] 1, 01 - variable capacity turbocharger, 2 - turbine wheel, 3 - first housing, 4 - second housing, 5 - variable nozzle device, 6, 06 - driving force transmission device, 7 - control arm, 8 - control lever, 9 - sleeve, 10 - other components, 11 - compressor wheel, 12 - third housing, 13 - bearing, 14 - bearing support portion, 20 - turbine rotor, 21 - turbine shaft, 22 - hub, 23 - turbine blade, 31 - scroll flow path, 32 - exhaust discharge flow path, 33 - accommodation space, 33A - gas flow path, 33B - rear side space, 41 - through hole, 47 - outer side space, 51 - driving force input portion, 51A - engaging pin, 52 - nozzle mounting member, 53 - nozzle blade, 54 - driving ring, 55 - lever plate, 56 - nozzle plate, 57 - nozzle support member, 60 - driver, 71 - engaging portion, 71A - insertion slot, 72 - rotation shaft portion, 72A - protruding portion, 73 - engaging plate, 81 - fixed portion, 81A - cylindrical portion, 82 - long plate, 100 - method of assembling variable capacity turbocharger, BM - brazing portion, F - external force, S1 - control arm insertion step, S2 - control arm engaging step, S3 - housing joining step, S4 - control lever fixing step, S5 - control arm adjusting step, W1, W2, W3 - welding portion.

Claims

1. A variable capacity type turbocharger, comprising: a turbine wheel; a first case having a scroll flow passage; a variable nozzle device configured to form a gas flow passage from the scroll flow passage toward the turbine wheel and adjust a flow direction of gas flowing through the gas flow passage; a second case coupled to the first case, forming an accommodation space that accommodates the turbine wheel and the variable nozzle device between the first case and the second case, and having a through-hole that communicates the accommodation space with an outside of the second case; and a driving force transmission device configured to transmit a driving force from a driver disposed outside of the second case to the variable nozzle device, wherein the driving force transmission device includes: a control arm having an engagement portion that engages with a driving force input portion of the variable nozzle device in the accommodation space and a rotation shaft portion that protrudes to the outside of the second case by passing through the through-hole; and a control lever disposed outside of the second case and having a fixed portion that is fixed to the rotation shaft portion of the control arm by engagement.

2. The variable capacity type turbocharger according to claim 1, wherein the fixed portion is engaged with the rotation shaft portion by welding or brazing.

3. The variable capacity type turbocharger according to claim 1, wherein the fixed portion is engaged with the rotation shaft portion by press fitting.

4. The variable capacity type turbocharger according to any one of claims 1 to 3, wherein the fixed portion includes a cylindrical portion having a circumferential inner surface that surrounds a circumferential outer surface of the rotation shaft portion that protrudes to the outside of the second case.

5. The variable capacity type turbocharger according to claim 4, wherein a screw fitting groove for screw fitting the rotation shaft portion of the control arm is formed on the circumferential inner surface of the cylindrical portion.

6. The variable capacity type turbocharger according to any one of claims 1 to 3, further comprising a sleeve disposed between the through-hole and the rotation shaft portion.

7. The variable capacity type turbocharger according to any one of claims 1 to 3, wherein the variable nozzle device includes: a nozzle mount that forms the gas flow passage with other components; a plurality of nozzle vanes rotatably supported to the nozzle mount; a driving ring disposed so as to be rotatable around an axis of the nozzle mount, having a plurality of fitted portions on a plurality of circumferential portions, and having the driving force input portion mounted thereto; and a plurality of lever plates each including a vane fixing portion fixed to one of the plurality of nozzle vanes and a fitted portion fitted to one of the plurality of fitted portions of the driving ring.

8. The variable capacity type turbocharger according to claim 7, wherein the driving force input portion of the variable nozzle device is constituted by an engagement pin mounted to the driving ring, and the engagement portion of the control arm is constituted by a hole or a slot into which the engagement pin is inserted.

9. A method of assembling a variable capacity type turbocharger, wherein the variable capacity type turbocharger includes: a turbine wheel; a first case having a scroll flow passage; ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ A variable nozzle device is configured to form a gas flow path from the scroll flow path toward the turbine wheel, and adjust a flow direction of gas flowing through the gas flow path. A second housing is coupled to the first housing, forms an accommodation space that accommodates the turbine wheel and the variable nozzle device between the first housing and the second housing, and has a through-hole that communicates the accommodation space with the outside of the second housing; and A drive force transmission device is configured to transmit a drive force from a driver disposed outside the second housing to the variable nozzle device, The drive force transmission device includes: A control arm has an engagement portion that engages the drive force input portion of the variable nozzle device in the accommodation space, and a rotation shaft portion that protrudes partially to the outside of the second housing by passing through the through-hole; and A control lever is disposed outside the second housing, and has a fixed portion that is fixed to the rotation shaft portion of the control arm by engagement, The assembly method of the variable displacement turbocharger includes: A control arm insertion step in which the rotation shaft portion of the control arm is inserted into the through-hole and protrudes partially to the outside of the second housing; A control arm engagement step in which, after the control arm insertion step, the engagement portion of the control arm is engaged with the drive force input portion of the variable nozzle device; A housing coupling step in which, after the control arm engagement step, the first housing and the second housing are coupled; and A control lever fixing step in which, after the housing coupling step, the fixed portion of the control lever is fixed to the rotation shaft portion of the control arm by engagement.

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