JP2017067051A - Variable nozzle turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable nozzle turbocharger in which reference value of a nozzle opening degree can be changed even after the turbocharger is assembled.SOLUTION: A variable nozzle turbocharger 10 comprises a variable nozzle mechanism 36 and a reference opening degree setting mechanism 70 for setting a reference value of a nozzle opening degree that is changed by the variable nozzle mechanism. The reference opening degree setting mechanism 70 comprises a shaft part 71 arranged to pass through a housing 12 from an outside part of a housing 12 toward an internal space of the housing 12 where the variable nozzle mechanism 36 is housed; and a cam 72 provided at the end part of the shaft part 71 and arranged at a position where the cam 72 can contact with at least one of an arm 49 and unison ring 52 within the housing 12. A movable range of the arm 49 is defined by rotating the shaft part 71 to change a position where the cam 72 contacts with at least one member described above and at the same time the reference value of the nozzle opening degree is defined.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a variable nozzle turbocharger including a variable nozzle mechanism.

  As disclosed in International Publication No. 2012/063359 (Patent Document 1), a variable nozzle turbocharger having a variable nozzle mechanism is known. In the variable nozzle mechanism disclosed in this document, the movable range (opening / closing range) of the nozzle vane is regulated by the fully closed stopper and the fully opened stopper.

  In this document, the housing accommodates a variable nozzle mechanism and the like, and a drive link for rotating the nozzle vane is provided outside the housing. The fully closed stopper in this document is disposed at a position facing the drive link (outside of the housing), and the position of the nozzle vane on the closing side (fully closed position) is regulated by the drive link hitting the fully closed stopper. The

  In general, in the variable nozzle mechanism, learning control of the fully closed position is executed. For example, when the engine is stopped, the drive link is abutted against a fully closed stopper as disclosed in the above document, and the opening command value at the abutted position, that is, the reference position (mechanical fully closed position), Learning is performed so that a value closer to the closing side (for example, opening degree command value = 105%) than the opening degree command value (100%) of the fully closed position is controlled. In the opening control (NV control) of the nozzle vane during normal engine operation, the opening command value is set within a range of 0% to 100% (100%: fully closed position for control) according to the engine operating state. The NV opening is controlled by adjusting.

International Publication No. 2012/063359

  In International Publication No. 2012/063359 (Patent Document 1), the position of the nozzle vane on the closing side (fully closed position) is regulated by the fully closed stopper coming into contact with the drive link outside the housing (external contact). Construction). The drive link is abutted against the fully closed stopper, and the opening command value at the abutted position, that is, the reference position (mechanical fully closed position) is closed from the opening command value (100%) of the fully closed position for control purposes. Learning to set a value on the side (for example, opening command value = 105%) is performed.

  Since the fully closed stopper disclosed in this document is provided outside the housing, the influence of wear over time on the arm or unison ring provided inside the housing (in other words, the drive link and the fully closed stopper) It is difficult to cancel with this fully-closed stopper (because of the influence of wear on the member ahead in the direction of power transmission than the point where the stopper contacts).

  On the other hand, it is also conceivable to provide a fully closed stopper inside the housing (internal abutting structure). However, if the fully closed stopper is simply placed inside the housing, the position at which the fully closed stopper contacts the arm or the like cannot be changed after the turbocharger is assembled, and the reference position (reference value of the nozzle opening) Is uniquely determined by the position, size and shape of the fully closed stopper, and it is not easy to optimize the reference position.

  The present invention has been made in view of the above circumstances, and is capable of changing the reference position (reference value of the nozzle opening) even after the turbocharger is assembled. It aims at providing the variable nozzle turbocharger provided with.

  A variable nozzle turbocharger according to the present invention includes a compressor wheel provided on an intake passage of an engine, a turbine wheel provided on an exhaust passage of the engine and connected to the compressor wheel via a shaft, and a plurality of A variable nozzle mechanism that has a variable nozzle and adjusts the flow rate of exhaust gas blown to the turbine wheel by changing the opening of the plurality of variable nozzles, the compressor wheel, the turbine wheel, and the variable nozzle mechanism And a reference opening setting mechanism for setting a reference value of the nozzle opening changed by the variable nozzle mechanism, the variable nozzle mechanism being connected to the arm and the arm. A nozzle vane and a unison ring engaged with the arm, and The unison ring rotates to rotate the arm and the nozzle vane, thereby changing the nozzle opening, and the reference opening setting mechanism includes the variable nozzle mechanism accommodated from the outside of the housing. A shaft portion disposed so as to pass through the housing toward the internal space of the housing, and an end portion of the shaft portion, and at least one member of the arm and the unison ring inside the housing A cam disposed at a position where the arm can be contacted, and the shaft is rotated to change a position where the cam contacts the at least one member, thereby defining a movable range of the arm. The reference value for the nozzle opening is defined.

  Preferably, the cam is disposed in a position where it can contact the arm inside the housing.

  Preferably, the shaft center of the cam is provided at a position shifted from the shaft center of the shaft portion.

  According to the above configuration, even after the turbocharger is assembled by utilizing the cam disposed in a position that can contact at least one of the arm and the unison ring inside the housing, It becomes possible to change the reference position (reference value of the nozzle opening).

FIG. 3 is a cross-sectional view along the rotation axis of the variable nozzle turbocharger in the first embodiment. FIG. 3 is a diagram illustrating a variable nozzle mechanism provided in the variable nozzle turbocharger in the first embodiment. 3 is an enlarged cross-sectional view of a reference opening degree setting mechanism provided in the variable nozzle turbocharger according to Embodiment 1. FIG. FIG. 3 is a perspective view showing a shaft portion and a cam of a reference opening setting mechanism provided in the variable nozzle turbocharger in the first embodiment. FIG. 6 is a perspective view showing a cam of a reference opening setting mechanism provided in the variable nozzle turbocharger in the second embodiment. FIG. 6 is a front view showing a cam of a reference opening setting mechanism provided in the variable nozzle turbocharger in the second embodiment. 6 is a diagram showing a variable nozzle mechanism provided in a variable nozzle turbocharger in Embodiment 3. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same reference numerals are used for the same members or corresponding parts, and the description thereof may not be repeated.

[Embodiment 1]
FIG. 1 is a cross-sectional view along the rotation axis of the variable nozzle turbocharger 10 according to the first embodiment. First, the overall structure of the variable nozzle turbocharger 10 will be described. In the present embodiment, a variable nozzle turbocharger 10 attached to an engine (internal combustion engine) mounted on a vehicle will be described as an example.

  As shown in FIG. 1, the variable nozzle turbocharger 10 includes a rotor 20 and a housing 12. The rotor 20 includes a turbine wheel 22, a shaft 24, and a compressor wheel 26 and is accommodated in the housing 12. A variable nozzle mechanism 36 (specifically, a variable nozzle 46, a support shaft 47, an arm 49, and the like) described later is also accommodated in the housing 12.

  The housing 12 of this embodiment includes a turbine housing 14, a compressor housing 16, and a center housing 18. The center housing 18 connects the turbine housing 14 and the compressor housing 16.

  The turbine wheel 22 is disposed in the turbine housing 14. The turbine wheel 22 has a plurality of turbine blades 23 on the outer peripheral portion thereof, and these turbine blades 23 are located on an exhaust passage of an engine (internal combustion engine) (not shown). The compressor wheel 26 is disposed in the compressor housing 16. The compressor wheel 26 has a plurality of impellers 27 on the outer peripheral portion, and these impellers 27 are located on an intake passage of an engine (internal combustion engine) (not shown).

  The shaft 24 is disposed in the center housing 18. The shaft 24 is rotatably supported with respect to the center housing 18 by a plurality of bearings. The turbine wheel 22 is connected to a compressor wheel 26 via a shaft 24, and the turbine wheel 22, the shaft 24, and the compressor wheel 26 can rotate together.

  A spiral scroll passage 30 is formed in the turbine housing 14. An annular turning passage 31 is opened in the scroll passage 30. The turning passage 31 faces the turbine blade 23 of the turbine wheel 22. The scroll passage 30 is located on an exhaust passage for exhaust gas discharged from a combustion chamber of an engine (internal combustion engine) (not shown). The exhaust gas flowing into the scroll passage 30 is blown from the turning passage 31 to the turbine blade 23 of the turbine wheel 22, thereby rotating the turbine wheel 22. Thereafter, the exhaust gas is discharged from the exhaust outlet 15 of the turbine housing 14.

  A spiral compressor passage 33 is formed in the compressor housing 16. An annular delivery passage 34 is opened in the compressor passage 33. The delivery passage 34 faces the impeller 27 of the compressor wheel 26. The compressor passage 33 communicates with the combustion chamber of the internal combustion engine via an intake passage (not shown). The compressor wheel 26 is rotated integrally with the rotation of the turbine wheel 22. The compressor wheel 26 compresses the intake air introduced from the intake inlet 17 of the compressor housing 16 by the impeller 27 and sends it to the delivery passage 34 by centrifugal action. The air released into the delivery passage 34 is supercharged into the combustion chamber of the internal combustion engine via the compressor passage 33.

(Variable nozzle mechanism 36)
FIG. 2 is a view showing the variable nozzle mechanism 36. FIG. 2 shows a part of the variable nozzle mechanism 36 (nozzle ring 38 and the like) viewed from the arm 49 side. With reference to FIGS. 1 and 2, the variable nozzle turbocharger 10 includes a variable nozzle mechanism 36. The variable nozzle mechanism 36 adjusts the flow rate of exhaust gas flowing through the swirl passage 31 toward the turbine wheel 22 (flow rate of exhaust gas blown to the turbine wheel 22).

  Specifically, the variable nozzle mechanism 36 includes an annular nozzle ring 38, an annular unison ring 52, and a plurality of (for example, nine) variable nozzles 46. The nozzle ring 38 constitutes a side wall of the turning passage 31 on the center housing 18 side. The nozzle ring 38 is fixed to the turbine housing 14 by a plurality of (for example, four) connecting bolts.

  An annular space 41 (FIG. 1) is formed on the outer peripheral portion of the joint portion between the turbine housing 14 and the center housing 18. The annular space 41 and the turning passage 31 are partitioned by the nozzle ring 38. A flange-shaped side wall portion 19 is formed on the outer peripheral portion of the center housing 18. The side wall portion 19 constitutes the side wall of the annular space portion 41. The side wall portion 19 is fixed to the turbine housing 14 with bolts 42.

  The plurality of variable nozzles 46 are arranged at equal intervals in the circumferential direction with respect to the nozzle ring 38. Each variable nozzle 46 includes a support shaft 47, a nozzle vane 48, and an arm 49. The nozzle vane 48 is fixed to one end of the support shaft 47. The arm 49 is fixed to the other end of the support shaft 47. The nozzle vane 48 is fixedly connected to the arm 49 via the support shaft 47.

  The support shaft 47 is disposed through the nozzle ring 38. The support shaft 47 is supported so as to be able to rotate with respect to the nozzle ring 38. The variable nozzle 46 is supported by a support shaft 47 so as to be rotatable with respect to the nozzle ring 38. A fitting portion 50 is formed at the tip of the arm 49. The nozzle vane 48 is disposed in the swivel passage 31 shown in FIG. The nozzle vane 48 is disposed so as to be able to open and close the turning passage 31. The arm 49 is disposed in the annular space 41 shown in FIG. 1 so as to be rotatable about the support shaft 47.

  The unison ring 52 is arrange | positioned in the annular space part 41 shown in FIG. The unison ring 52 is disposed concentrically with the nozzle ring 38. The unison ring 52 is disposed on the side wall 19 side of the center housing 18 shown in FIG. The unison ring 52 is disposed between the nozzle ring 38 and the arm 49 of the variable nozzle 46, as shown in FIG.

  A holding roller 44 is disposed on the annular space 41 side of the nozzle ring 38. The holding roller 44 is rotatably held with respect to the nozzle ring 38. The holding roller 44 holds the unison ring 52 rotatably. The unison ring 52 is rotatably held with respect to the turbine housing 14 by the holding roller 44.

  As shown in FIG. 2, on one side surface of the unison ring 52 (the side where the arm 49 of the variable nozzle 46 is provided), the same number of arm fitting grooves 54 as the number of the variable nozzles 46 are equally spaced in the circumferential direction. It is formed with. The arm fitting groove 54 is formed in a straight line in the radial direction of the unison ring 52. In each arm fitting groove 54, the fitting portion 50 of the arm 49 of each variable nozzle 46 is fitted. The arm 49 of the variable nozzle 46 is engaged with the arm fitting groove 54 of the unison ring 52.

(Drive member 56)
A drive member 56 for rotationally driving the unison ring is provided on the side wall 19 of the center housing 18 shown in FIG. The drive member 56 has a support shaft 57, a drive lever 58, and a drive arm 60. The drive lever 58 is fixed to one end of the support shaft 57. The drive arm 60 is fixed to the other end of the support shaft 57.

  The support shaft 57 is disposed through the side wall 19 of the center housing 18. The support shaft 57 is supported so as to be rotatable with respect to the side wall portion 19. The drive member 56 is supported by the support shaft 57 so as to be rotatable with respect to the side wall portion 19 of the center housing 18. The drive lever 58 is disposed outside the annular space 41. The drive arm 60 is accommodated in the annular space 41. A circular fitting portion 61 is formed at the distal end portion of the drive arm 60.

  As shown in FIG. 2, one drive arm fitting groove 63 is formed on one side surface of the unison ring 52 (the side where the arm 49 of the variable nozzle 46 is provided). The drive arm fitting groove 63 is formed between a pair of arm fitting grooves 54 adjacent in the circumferential direction of the unison ring 52. The drive arm fitting groove 63 is formed in a straight line in the radial direction of the unison ring 52. A fitting portion 61 of the driving arm 60 is fitted in the driving arm fitting groove 63. The drive arm 60 is engaged with the drive arm fitting groove 63 of the unison ring 52.

  As shown in FIG. 1, an output portion (not shown) of the actuator 65 is linked to the drive lever 58. The actuator 65 is, for example, an electric motor, an electromagnetic solenoid, an air cylinder, or the like. A power transmission mechanism such as a link mechanism or a gear mechanism may be interposed between the output portion of the actuator 65 and the drive arm 60 of the drive member 56.

  The actuator 65 is driven and controlled by the controller 67. The actuator 65 is provided with an operation amount detecting means 68 such as an angle sensor for detecting the operation amount of the output portion. The controller 67 calculates the rotation angle of the variable nozzle 46 (the opening degree of the variable nozzle 46) based on the output of the operation amount detection means 68.

  When the actuator 67 is operated by the controller 67, the drive lever 58 is rotated. The drive arm 60 rotates around the support shaft 57 together with the drive lever 58. As the drive arm 60 rotates, the unison ring 52 rotates. As the unison ring 52 rotates, the plurality of variable nozzles 46 are rotated synchronously.

  When the unison ring 52 rotates in the clockwise direction in FIG. 2 (see arrow Y1), all the variable nozzles 46 are rotated in the clockwise direction in FIG. At this time, adjacent nozzle vanes 48 move away from each other. As the nozzle vane 48 moves, the cross-sectional area of the exhaust gas between adjacent nozzle vanes 48 increases. The rotating direction around the support shaft 47 of the arm 49 at this time is referred to as an opening direction in this specification.

  When the unison ring 52 rotates counterclockwise in FIG. 2 (see arrow Y2), all the variable nozzles 46 are rotated counterclockwise in FIG. 2 about the axis of the support shaft 47. The At this time, adjacent nozzle vanes 48 move in a direction approaching each other. As the nozzle vane 48 moves, the flow passage cross-sectional area of the exhaust gas between the adjacent nozzle vanes 48 becomes smaller. The rotating direction of the arm 49 around the support shaft 47 at this time is referred to as a closing direction in this specification.

  In this way, the opening degrees of the plurality of variable nozzles 46 (specifically, the nozzle vanes 48) are adjusted by synchronously rotating all the variable nozzles 46 based on the rotation of the unison ring 52. The flow rate or flow velocity of the exhaust gas blown to the turbine wheel 22 is adjusted by opening and closing the nozzle vanes 48 and increasing or decreasing the flow path cross-sectional area between the adjacent nozzle vanes 48.

  The variable nozzle mechanism 36 includes a variable nozzle 46, a unison ring 52, a drive member 56, and an actuator 65. The arm 49 and unison ring 52 of the variable nozzle 46, the drive arm 60 of the unison ring 52 and drive member 56, the drive lever 58 of the drive member 56 and the output of the actuator 65 are in the power transmission path from the actuator 65 to the arm 49. The members are connected to each other.

(Standard opening setting mechanism)
As shown in FIGS. 1 and 2, the variable nozzle turbocharger 10 includes a reference opening setting mechanism 70. The reference opening setting mechanism 70 sets a reference value for the nozzle opening that is changed by the variable nozzle mechanism 36. FIG. 3 is an enlarged cross-sectional view of the reference opening setting mechanism 70. FIG. 4 is a perspective view showing the shaft portion 71 and the cam 72 of the reference opening setting mechanism 70.

  As shown in FIGS. 1 to 4, the reference opening setting mechanism 70 in the present embodiment includes a shaft portion 71, a cam 72, a seal 73, and a nut 74. The shaft portion 71 is disposed so as to penetrate the housing 12 from the outside of the housing 12 (FIG. 1) toward the internal space (annular space portion 41) of the housing 12 in which the variable nozzle mechanism 36 is accommodated. In the present embodiment, a through hole 18H is formed in the side wall portion 19 of the center housing 18, and the shaft portion 71 is disposed so as to penetrate the side wall portion 19 through the through hole 18H. A seal 73 is provided between the inner peripheral surface of the through hole 18 </ b> H and the shaft portion 71.

  The cam 72 is provided at one end of the shaft portion 71, and is disposed at a position where it can contact at least one member of the arm 49 and the unison ring 52 inside the housing 12 (annular space portion 41). Yes. In the present embodiment, the cam 72 is positioned so that the side peripheral surface 72T of the cam 72 faces the side surface 49T (see FIG. 2) of the arm 49 and the side peripheral surface 72T of the cam 72 can contact the arm 49. Has been placed.

  Referring to FIG. 2, the position where cam 72 contacts arm 49 is changed by rotating cam 72. By fixing the cam 72 in a predetermined posture (rotation angle) using the nut 74, a movable range on the closing side of the arm 49 is defined, and a reference value (fully closed position) of the nozzle opening is defined. It will be.

  For example, the arm 49 is abutted against the cam 72, and the opening command value at the abutted position, that is, the reference position (mechanical fully closed position) is set to be larger than the opening command value (100%) of the fully closed position in terms of control. Learning is performed such that the closing side value (for example, opening command value = 105%) is set. In the opening control (NV control) of the nozzle vane during normal engine operation, the opening command value is set within a range of 0% to 100% (100%: fully closed position for control) according to the engine operating state. Adjust and control the NV opening.

  In the variable nozzle mechanism 36 in the present embodiment, even after the variable nozzle turbocharger 10 is assembled, the cam 72 is rotated via the shaft portion 71 so that the cam 72 is brought into contact with the arm 49. Can change. Therefore, the reference position (reference value of the nozzle opening) can be optimized even after the variable nozzle turbocharger 10 is assembled. The optimization can be appropriately performed, for example, immediately before the shipment of the product or at the periodic inspection of the engine.

  In addition, unlike the so-called external abutment structure described at the beginning, in the case of the present embodiment, the cam 72 is in direct contact with the arm 49 so that the reference value of the nozzle opening (fully closed position) is set. It is prescribed. According to the reference opening setting mechanism 70, the influence of wear over time that may occur in each member provided in the power transmission path to the actuator 65, the drive lever 58, the support shaft 57, the drive arm 60, the unison ring 52, and the nozzle vane 48. If so, it is possible to reduce even the influence of wear over time generated in the arm 49, the unison ring 52 and the like provided inside the housing 12. The robustness with respect to the deviation of the VN opening degree is improved, and the designed VN movable range can be expanded. Furthermore, the flow rate standard can maintain the conventional level.

  In order to make it possible to finely adjust the rotation angle of the shaft portion 71, the shaft portion 71 may be rotated using a dedicated jig, or rotated using a reduction gear mechanism using gears having different diameters. Also good.

[Embodiment 2]
5 and 6 are a perspective view and a front view, respectively, showing a reference opening setting mechanism 70A (cam 72) applicable to the variable nozzle turbocharger in the second embodiment.

  In the reference opening setting mechanism 70A of the present embodiment, the shaft center 72C of the cam 72 is provided at a position shifted from the shaft center 71C of the shaft portion 71 (see FIG. 6). By utilizing the difference in the distance from the shaft center 71C to the side peripheral surface 72T, the position at which the cam 72 contacts the arm 49 (see FIG. 2 etc.) can be changed. Closed position).

  Further, when the shaft center 72C of the cam 72 and the shaft center 71C of the shaft portion 71 coincide with each other, the reference value of the nozzle opening is determined by the rotation of the shaft portion 71 depending on the shape of the side peripheral surface 72T of the cam 72. Is relatively large. This can be said that the sensitivity to the rotation of the shaft portion 71 is high and the adjustment range of the reference value of the nozzle opening can be increased.

  On the other hand, since the shaft center 72C of the cam 72 is provided at a position shifted from the shaft center 71C of the shaft portion 71 as in the present embodiment, the reference value of the nozzle opening degree due to the rotation of the shaft portion 71. Can be changed relatively small. Sensitivity to the rotation of the shaft portion 71 becomes moderate, and the reference value of the nozzle opening can be finely adjusted.

[Embodiment 3]
FIG. 7 is a diagram showing a reference opening degree setting mechanism 70B applicable to the variable nozzle turbocharger in the third embodiment. In the above-described first embodiment, the cam 72 is disposed at a position where it can contact the arm 49 inside the housing 12 (annular space portion 41).

  In the reference opening setting mechanism 70 </ b> B of the present embodiment, the cam 72 is provided at a position where it can contact the unison ring 52. The unison ring 52 is provided with a notch 52T, and the radially outer portion of the cam 72 is located inside the notch 52T. The position where the unison ring 52 contacts the cam 72 is changed depending on the relative positional relationship or the angular relationship between the notch 52T and the cam 72. By fixing the cam 72 in a predetermined posture (rotation angle) using the nut 74, the movable range on the closed side of the unison ring 52 is defined, and consequently the movable range on the closed side of the arm 49 is defined. The reference value (fully closed position) is defined.

  Also according to the configuration of the third embodiment, substantially the same operational effects as those of the first embodiment described above can be obtained. When viewed from the power transmission path, the configuration of the third embodiment regulates the reference value (fully closed position) of the nozzle opening on the upstream side of the configuration of the first embodiment. Therefore, when it is desired to further reduce the influence of wear or the like, it can be said that the configuration of the first embodiment is more preferable than the third embodiment. Depending on the overall configuration and arrangement of the variable nozzle turbocharger, the cam 72 may be configured to come into contact with both the arm 49 and the unison ring 52. You may comprise so that it can contact one side.

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

  DESCRIPTION OF SYMBOLS 10 Variable nozzle turbocharger, 12 Housing, 14 Turbine housing, 15 Exhaust outlet, 16 Compressor housing, 17 Intake inlet, 18 Center housing, 18H Through-hole, 19 Side wall part, 20 Rotor, 22 Turbine wheel, 23 Turbine blade, 24 Shaft , 26 Compressor wheel, 27 Impeller, 30 Scroll passage, 31 Rotation passage, 33 Compressor passage, 34 Delivery passage, 36 Variable nozzle mechanism, 38 Nozzle ring, 41 Annular space, 42 Bolt, 44 Holding roller, 46 Variable nozzle, 47 , 57 support shaft, 48 nozzle vane, 49 arm, 49T side, 50, 61 joint, 52 unison ring, 54, 63 arm fitting groove, 56 drive member, 58 drive lever, 60 drive arm, 6 5 Actuator, 67 Controller, 68 Actuation amount detection means, 70, 70A, 70B Reference opening setting mechanism, 71 shaft part, 71C, 72C shaft center, 72 cam, 72T side peripheral surface, 73 seal, 74 nut, Y1, Y2 Arrow.

Claims (3)

A compressor wheel provided on the intake passage of the engine;
A turbine wheel provided on the exhaust passage of the engine and connected to the compressor wheel via a shaft;
A variable nozzle mechanism that has a plurality of variable nozzles and adjusts the flow rate of exhaust gas blown to the turbine wheel by changing the opening of the plurality of variable nozzles;
A housing that houses the compressor wheel, the turbine wheel, and the variable nozzle mechanism;
A reference opening setting mechanism for setting a reference value of the nozzle opening changed by the variable nozzle mechanism,
The variable nozzle mechanism includes an arm, a nozzle vane connected to the arm, and a unison ring engaged with the arm, and the unison ring rotates to rotate the arm and the nozzle vane. , The nozzle opening is changed,
The reference opening setting mechanism is
A shaft portion arranged to penetrate the housing from the outside of the housing toward the internal space of the housing in which the variable nozzle mechanism is accommodated;
A cam provided at an end of the shaft portion and disposed at a position in contact with at least one member of the arm and the unison ring inside the housing;
By rotating the shaft portion and changing the position where the cam contacts the at least one member, the movable range of the arm is defined, and the reference value of the nozzle opening is defined.
Variable nozzle turbocharger. The cam is disposed at a position where it can contact the arm inside the housing.
The variable nozzle turbocharger according to claim 1. The shaft center of the cam is provided at a position shifted from the shaft center of the shaft portion.
The variable nozzle turbocharger according to claim 1 or 2.