Turbine and turbocharger

Abstract

Turbine (10, 10A) with: a turbine wheel (12); a turbine housing (11) which has a flow path through which a gas flows and is taken in by an inlet port; a bearing housing (3); a variable geometry mechanism (30) arranged within the turbine housing (11) and configured to receive the gas from the flow path and direct the gas to the turbine wheel (12), wherein the variable geometry mechanism (30) comprises a disk-shaped nozzle ring (32) having a main surface (32a) facing the turbine wheel (12) and a rear surface (32b), and nozzle guide vane units (300) each comprising a nozzle guide vane (34) arranged on one side of the main surface (32a) of the nozzle ring (32), a nozzle shaft (37) extending from the nozzle guide vane (34) and passing through the nozzle ring (32), and a nozzle coupling plate (36) arranged on one side of the rear surface (32b) of the nozzle ring (32) and connected to a distal end of the nozzle shaft (37) is connected; and a preload element (39, 41) which is arranged between the nozzle coupling plate (36) and the bearing housing (3) is in contact with a coupling plate rear surface (36b) of the nozzle coupling plate (36) and applies a preload force in an axial direction of the nozzle shaft (37), wherein the nozzle guide vane (34) is in contact with a section facing the nozzle guide vane (34) due to the preload force, wherein the nozzle coupling plate (36) comprises a first region (S1) which, when viewed in the axial direction, overlaps with the nozzle guide vane (34), and a second region (S2) that does not overlap with the nozzle guide vane (34), and wherein a section in which the preloading element (39, 41) is in contact with the nozzle coupling plate (36) is positioned in the second region (S2).

Description

Technical field

[0001] The present invention relates to a turbine and a turbocharger. State of the art

[0002] JP 2006-207534A discloses a turbocharger incorporating a variable geometry mechanism. The variable geometry mechanism controls the flow rate of an exhaust gas fed from a screw-type flow path to a turbine. The variable geometry mechanism adjusts the exhaust gas flow rate by modifying the angle of nozzle guide vanes to change the cross-sectional area of ​​the flow path through which the exhaust gas flows.

[0003] EP 2 233 718 A1 relates to a turbocharger with a turbine in which a disc spring is arranged between corresponding nozzle guide vane shafts and a bearing housing. DE 10 2009 007 663 A1 and DE 10 2008 000 776 A1 disclose further prior art. Summary of the invention

[0004] Improved reliability is desired in a turbine featuring a variable geometry mechanism (VGM), enabling it to deliver the desired performance across diverse operating environments. Irregular external forces acting on the VGM reduce its reliability. For example, the VGM is located along a path that carries exhaust gas from a power engine to a turbine wheel. The condition of the exhaust gas varies depending on the power engine's operating state. These changes in exhaust gas condition affect the components forming the VGM. Furthermore, these components are also affected by vibrations or shocks experienced by the turbine.

[0005] The object of the present invention is to solve the problems discussed above in the prior art and to provide a turbine that is able to improve reliability and a turbocharger that incorporates the turbine.

[0006] The above problem is solved by a turbine according to claim 1 and a turbine according to claim 5. The above problem is further solved by a turbocharger according to claim 6, which incorporates the turbine according to the invention.

[0007] The turbine and turbocharger according to the invention are able to improve reliability.

[0008] Further advantageous embodiments are disclosed in the dependent patent claims. Brief description of the drawings Fig. Figure 1 is a sectional view of a turbocharger comprising a turbine of a first embodiment. Fig. Figure 2 is a perspective exploded view showing a variable geometry mechanism and a prestressing element, which are located in Fig. 1 are shown. Fig. Figure 3 is an enlarged sectional view of main parts of the variable geometry mechanism and the preload element of the turbine of the first embodiment. Fig. Figure 4 is a top view of the variable geometry mechanism and the preload element of the turbine of the first embodiment. Fig. Figure 5 is an enlarged sectional view of main parts of a variable geometry mechanism and a preload element of a turbine of a second embodiment. Fig. Figure 6 is a top view of the variable geometry mechanism and the preload element of the turbine of the second embodiment. Fig. Figure 7 is an enlarged sectional view of main parts of a variable geometry mechanism and a preload element of a turbine of a third embodiment (not belonging to the invention). Fig. Figure 8 is a top view of the variable geometry mechanism and the preload element of the turbine of the third embodiment. Fig. Figure 9 is an enlarged sectional view of main parts of a variable geometry mechanism and a preload element of a turbine of a fourth embodiment. Fig. Figure 10 is a top view of the variable geometry mechanism and the preload element of the turbine of the fourth embodiment. Fig. Figure 11 is an enlarged sectional view of main parts of a variable geometry mechanism and a preload element of a turbine of a first variation (not belonging to the invention). Fig. Figure 12 is an enlarged sectional view of main parts of a variable geometry mechanism and a preload element of a turbine (not belonging to the invention) of a second variation. Fig. Figure 13 is a sectional view of a turbocharger featuring a turbine of a third variation. Fig. Figure 14 is an enlarged sectional view of main parts of a variable geometry mechanism and a preload element of a turbine of a fourth variation. Description of the embodiments

[0009] A turbine of one aspect of the present disclosure comprises a turbine wheel; a casing having a flow path through which a gas flows, which is received from an inlet port; a variable geometry mechanism arranged within the casing and configured to receive the gas from the flow path and to direct the gas to the turbine wheel, wherein the variable geometry mechanism comprises a disk-shaped nozzle ring having a main surface facing the turbine wheel and a rear surface, and nozzle guide vane units, each comprising a nozzle guide vane arranged on one side of the main surface of the nozzle ring, a nozzle shaft extending from the nozzle guide vane and passing through the nozzle ring, and a nozzle coupling plate arranged on one side of the rear surface of the nozzle ring and connected to a distal end of the nozzle shaft;and a preload element that is in contact with the nozzle guide vane units and applies a preload force in an axial direction of the nozzle shaft. Due to the preload force, the nozzle guide vane rests against a section facing the nozzle guide vane.

[0010] The turbine features a preload element that applies a preload force, directed axially along the nozzle shaft, to the nozzle guide vane assemblies. The nozzle guide vane assemblies, to which the preload force is applied, bear against the section facing the nozzle guide vane. Only rotation around the nozzle shaft is possible as the movement of each nozzle guide vane assembly relative to the nozzle ring. Any other movement of the nozzle guide vane assemblies, such as unintended wobbling, is suppressed. Accordingly, irregular movement of the nozzle guide vane assemblies relative to the nozzle ring does not occur, even if the nozzle guide vanes are subjected to an irregular external force.The state of the component group forming the variable geometry mechanism can be preferentially maintained, thus preserving a state in which the variable geometry mechanism is able to deliver the desired performance. The reliability of the turbine, which incorporates the variable gear mechanism, can therefore be improved.

[0011] The variable geometry mechanism can further include a disc element that, together with the nozzle ring, interpositions the nozzle guide vanes. The section facing the nozzle guide vane can be the disc element. The disc element allows for precise adjustment of the distance between the disc element and the nozzle ring. It also allows for precise adjustment of the gap formed between the nozzle guide vane and the disc element. Furthermore, the disc element allows for precise adjustment of a preload force capable of suppressing irregular movement of the nozzle guide vane without restricting its rotation around the nozzle shaft.

[0012] The casing can have a flow path surface facing an end face of the nozzle guide vane, opposite an end face where the nozzle shaft is located. The section facing the nozzle guide vane can be the flow path surface of the casing. Such a configuration eliminates the need for a separate component with which the nozzle guide vane comes into contact. Accordingly, the turbine can have a simple configuration.

[0013] The distance from the nozzle ring along the axial direction to the nozzle coupling plate can be greater than the distance from the nozzle guide vane along the axial direction to the section facing the nozzle guide vane. The nozzle guide vane can be reliably brought into contact with the section facing the nozzle vane.

[0014] The nozzle coupling plate can have a first region that overlaps the nozzle guide vane when viewed in the axial direction, and a second region that does not. The section where the preload element is in contact with the nozzle coupling plate can be positioned in the second region. In such a configuration, the preload force is applied to a region located away from the nozzle shaft. The distance between the position where the nozzle shaft connects to the nozzle coupling plate and the position on the nozzle coupling plate where the preload force acts is increased. The moment attempting to tilt the nozzle guide vane assembly relative to the axis of rotation of the nozzle shaft is increased. The frictional force generated by the nozzle shaft as it comes into contact with the inner circumferential surface of the nozzle ring's through-hole is also increased.Accordingly, a movement such as an unintentional stagger is further suppressed.

[0015] A turbine of another aspect of the present disclosure comprises a turbine wheel; a casing having a flow path through which a gas flows, having been drawn in through an inlet port; a variable geometry mechanism arranged within the casing and configured to draw the gas from the flow path and direct the gas to the turbine wheel, the variable geometry mechanism comprising a disk-shaped nozzle ring having a main surface facing the turbine wheel and a rear surface, and nozzle guide vane units, each comprising a nozzle guide vane arranged on one side of the main surface of the nozzle ring, a nozzle shaft extending from the nozzle guide vane and passing through the nozzle ring, and a nozzle coupling plate arranged on one side of the rear surface of the nozzle ring and connected to a distal end of the nozzle shaft;and a preload element that is in contact with the nozzle guide vane units and applies a preload force in a radial direction to the nozzle shaft. The nozzle shaft rests against an inner circumferential surface of a through-hole in the nozzle ring.

[0016] The nozzle shaft rests against the inner circumferential surface of the nozzle ring's through-hole. As a result, only one rotation around the nozzle shaft is possible for each nozzle guide vane assembly relative to the nozzle ring. This means that any other movement of the nozzle guide vane assemblies, such as unintended wobbling, is suppressed. Consequently, irregular movement of the nozzle guide vane assemblies does not occur, even if the nozzle guide vanes are subjected to irregular forces. The state of the component group forming the variable geometry mechanism can be preferentially maintained, thus preserving the state in which the variable geometry mechanism is able to deliver the desired performance. The reliability of the turbine incorporating the variable geometry mechanism can therefore be improved.

[0017] Another aspect of the present invention is a turbocharger comprising the turbine described above. The turbocharger incorporates the turbine described above, enabling it to improve reliability.

[0018] The turbocharger, which incorporates the turbine of the present disclosure, is described in detail below with reference to the accompanying drawings. In the description of the drawings, the same elements are given the same reference numerals, and redundant descriptions are omitted.

[0019] As in Fig. Figure 1 shows a turbocharger 1 according to a first embodiment of a variable geometry design. The turbocharger 1 is applied, for example, to an internal combustion engine of a ship or a vehicle. The turbocharger 1 has a turbine 10 and a compressor 20. The turbine 10 has a turbine housing 11, a turbine wheel 12, a variable geometry mechanism 30, and a bearing housing 3. The compressor 20 has a compressor housing 21 and a compressor wheel 22.

[0020] The turbine wheel 12 is located at a first end section of a shaft 2. The compressor wheel 22 is located at a second end section of the shaft 2. The bearing housing 3 is located between the turbine housing 11 and the compressor housing 21. A bearing 4 is arranged in the bearing housing 3. The shaft 2 is rotatably supported by the bearing 4 through the bearing housing 3.

[0021] The turbine housing 11 has an inlet port 11R, a spiral flow path 13, and an outlet port 14. The inlet port 11R receives exhaust gas from the internal combustion engine into the turbine housing 11. The spiral flow path 13 extends circumferentially around a rotation axis AX around the turbine wheel 12. The spiral flow path 13 guides the gas received by the inlet port 11R to the turbine wheel 12. The exhaust gas, which is guided to the turbine wheel 12 via the variable geometry mechanism 30, rotates the turbine wheel 12. After the turbine wheel 12 has rotated, the exhaust gas flows out of the turbine housing 11 through the outlet port 14.

[0022] In particular, the turbine 10 has a connecting flow path S. The connecting flow path S carries the exhaust gas from the screw flow path 13 to the turbine wheel 12. The connecting flow path S has a plurality of nozzles. The plurality of nozzles are formed by a plurality of nozzle guide vanes 34. Specifically, a nozzle is a chamber surrounded by a pair of nozzle guide vanes 34, a CC plate 31, and a nozzle ring 32, which are described in more detail below. The plurality of nozzle guide vanes 34 are arranged equidistant from one another on a reference circle around the axis of rotation AX. Each nozzle guide vane 34 rotates about a nozzle axis NX, which is parallel to the axis of rotation AX. The cross-sectional area of ​​the nozzles is adjusted by the rotation of the plurality of nozzle guide vanes 34. The turbine 10 has the variable geometry mechanism 30 as a mechanism for adjusting the cross-sectional area of ​​the nozzles.

[0023] The compressor housing 21 has a screw conveyor 23, an intake port 24, and a discharge port 21R. The compressor wheel 22 rotates via the shaft 2 in conjunction with the rotation of the turbine wheel 12. The rotating compressor wheel 22 draws in ambient air through the intake port 24. The intake air is compressed as it passes through the compressor wheel 22 and the screw conveyor 23. The compressed air is discharged from the discharge port 21R. The compressed air is then supplied to the internal combustion engine.

[0024] The variable geometry mechanism 30 has a free-running control plate and the nozzle ring 32. The free-running control plate is referred to as a "CC plate 31". The CC plate 31 is disc-shaped. The nozzle ring 32 is disc-shaped. A central axis of the CC plate 31 coincides with a central axis of the nozzle ring 32. The central axis of the CC plate 31 coincides with the axis of rotation AX. The central axis of the nozzle ring 32 coincides with the axis of rotation AX. The CC plate 31 is positioned closer to the turbine housing 11 in one direction of the axis of rotation AX. The nozzle ring 32 is positioned closer to the bearing housing 3 in the direction of the axis of rotation AX. The interval between the CC plate 31 and the nozzle ring 32 is the connecting flow path S. The plurality of nozzle guide vanes 34 are arranged between the CC plate 31 and the nozzle ring 32.

[0025] As in Fig. As shown in Figure 2, the variable geometry mechanism 30 has the CC plate 31, the nozzle ring 32, a free-running control pin, and a drive ring 35. The free-running control pin is referred to as a "CC pin 33". The variable geometry mechanism 30 also has nozzle guide vane units 300.

[0026] The CC plate 31 has a main plate surface 31a, a rear plate surface 31b, and a plate hole 31h. The main plate surface 31a faces an inner surface of the turbine housing 11 (see Fig. 1) The plate's rear surface 31b faces the nozzle ring 32. The plate hole 31h is a through hole extending from the plate's main surface 31a to the plate's rear surface 31b. The CC plate 31 is provided with a plate pin hole 31p. The plate pin hole 31p has an opening that extends at least into the plate's rear surface 31b. The CC pin 33 is inserted into the plate pin hole 31p through the opening formed in the plate's rear surface 31b.

[0027] The nozzle ring 32 has a nozzle ring body 32d and a nozzle ring flange 32f. The nozzle ring body 32d is a cylindrical section. The nozzle ring body 32d has a plurality of nozzle shaft holes 32s. The nozzle shaft holes 32s are through holes. The intervals between the plurality of nozzle shaft holes 32s in the circumferential direction are equal to each other. The nozzle ring flange 32f projects radially from an outer circumferential surface of the nozzle ring body 32d. The nozzle ring flange 32f has a flange pin hole 32p. A central axis of the flange pin hole 32p coincides with a central axis of the plate pin hole 31p.

[0028] The nozzle ring 32 has a nozzle ring main surface 32a, a nozzle ring rear surface 32b, and a nozzle ring hole 32h. The nozzle ring main surface 32a faces the CC plate 31. The nozzle ring main surface 32a is oriented in one direction towards the turbine wheel 12. The nozzle ring rear surface 32b has a body rear surface 32b1 and a flange rear surface 32b2. The body rear surface 32b1 is an end surface of the nozzle ring body 32d. The body rear surface 32b1 is oriented towards the bearing housing 3. Openings for the nozzle shaft holes 32s are formed in the body rear surface 32b1. A section of a nozzle coupling plate 36 is arranged on the body rear surface 32b1. Accordingly, a section of the body rear surface 32b1 faces the nozzle coupling plate 36. The flange rear surface 32b2 is an end surface of the nozzle ring flange 32f. The flange rear surface 32b2 is also directed towards the bearing housing 3.The drive ring 35, which is described below, is arranged on the flange rear surface 32b2. Accordingly, the flange rear surface 32b2 faces the drive ring 35.

[0029] The CC pin 33 connects the CC plate 31 to the nozzle ring 32. The CC pin 33 is inserted into the plate pin hole 31p. The CC pin 33 is also inserted into the flange pin hole 32p. The CC pin 33 defines the gap between the CC plate 31 and the nozzle ring 32.

[0030] The drive ring 35 is arranged on the nozzle ring flange 32f. In particular, the drive ring 35 is arranged on the flange rear surface 32b2. The drive ring 35 is a ring-like element about the axis of rotation AX. The drive ring 35 has a drive ring hole 35h. The drive ring 35 surrounds the nozzle ring body 32d, which is arranged circumferentially in the drive ring hole 32h. The drive ring 35 is coaxial with the nozzle ring 32. The drive ring 35 is rotatable about the axis of rotation AX with respect to the nozzle ring 32.

[0031] The drive ring 35 has a main drive ring surface 35a and a rear drive ring surface 35b. The main drive ring surface 35a faces the nozzle ring 32. In particular, the main drive ring surface 35a faces the flange rear surface 32b2 of the nozzle ring 32. A plurality of nozzle coupling plates 36 are arranged on the rear drive ring surface 35b. A section of the rear drive ring surface 35b faces the nozzle coupling plates 36. A drive coupling plate 38 is also arranged on the rear drive ring surface 35b.

[0032] The drive ring 35 has a connection point 35J. The nozzle coupling plate 36 is fitted into the connection point 35J. A plurality of connection points 35J are provided equidistantly in the circumferential direction. Each connection point 35J has a pair of raised sections 35J1. The raised sections 35J1 project from the rear surface 35b of the drive ring. The raised sections 35J1 project towards the bearing housing 3. A distal coupling plate end 36e of the nozzle coupling plate 36 is fitted between a pair of the raised sections 35J1.

[0033] The nozzle guide vane units 300 each comprise the nozzle guide vane 34, a nozzle shaft 37, and the nozzle coupling plate 36. One nozzle guide vane unit 300 is arranged for each nozzle shaft hole 32s of the nozzle ring 32. One nozzle guide vane unit 300 is arranged for each connection point 35J of the drive ring 35. The intervals between the nozzle guide vane units 300 are the same in the circumferential direction.

[0034] As in Fig. As shown in Figure 3, the nozzle guide vane 34 is arranged between the CC plate 31 and the nozzle ring 32. The nozzle guide vane 34 has a main guide vane surface 34a and a back guide vane surface 34b. The main guide vane surface 34a faces the back surface 31b of the CC plate 31. The back guide vane surface 34b faces the main nozzle ring surface 32a of the nozzle ring 32. A length from the main guide vane surface 34a along the direction of the nozzle axis NX to the back guide vane surface 34b is defined as the nozzle guide vane width. A distance from the back surface 31b of the CC plate 31 to the main nozzle ring surface 32a is defined as the connecting flow path width. The connecting flow path width is slightly larger than the nozzle guide vane width. Accordingly, there is a small first gap C1 between the guide vane main surface 34a and the plate back surface 31b.Furthermore, there is a small second gap C2 between the guide vane back surface 34b and the nozzle ring main surface 32a. The nozzle guide vane 34 is able to move relative to the CC plate 31 by the length of the first gap C1 in the direction of the axis of rotation AX. The nozzle guide vane 34 is able to move relative to the nozzle ring 32 by the length of the second gap C2 in the direction of the axis of rotation AX.

[0035] The nozzle shaft 37 is attached to the guide vane's rear surface 34b. Specifically, the nozzle shaft 37 has a nozzle shaft base end 37f and a distal nozzle shaft end 37e. The nozzle shaft base end 37f is fixed to the guide vane's rear surface 34b. The nozzle shaft 37 passes through the nozzle shaft hole 32s of the nozzle ring 32. The distal nozzle shaft end 37e is positioned protruding from the body's rear surface 32b1 of the nozzle ring 32. The nozzle shaft 37 has an outer circumferential surface 37s. The outer circumferential surface 37s faces an inner circumferential surface 32s1 of the nozzle shaft hole 32s. A small third gap C3, which allows the nozzle shaft 37 to rotate, is located between the inner circumferential surface 32s1 and the outer circumferential surface 37s of the nozzle shaft. The nozzle coupling plate 36 is fixed to the distal end 37e of the nozzle shaft.

[0036] The nozzle coupling plate 36 is a rod-like element. The nozzle coupling plate 36 has a main coupling plate surface 36a and a rear coupling plate surface 36b. The nozzle coupling plate 36 is arranged on the rear nozzle ring surface 32b. In particular, the nozzle coupling plate 36 has a section that is arranged on the rear body surface 32b1 and a section that is arranged on the flange rear surface 32b2. The main coupling plate surface 36a faces the flange rear surface 32b2 of the nozzle ring 32, the drive ring rear surface 35b, and the rear body surface 32b1 of the nozzle ring 32. The rear coupling plate surface 36b faces a main bearing housing surface 3a of the bearing housing 3. The rear coupling plate surface 36b also faces a disc spring 39, which is described further below.

[0037] The nozzle coupling plate 36 has a coupling plate base end 36f, which is a first end section, and a distal coupling plate end 36e, which is a second end section. The coupling plate base end 36f is located on the rear surface 32b1 of the body. The coupling plate base end 36f is provided with a coupling plate hole 36s. The distal nozzle shaft end 37e of the nozzle shaft 37 is inserted into the coupling plate hole 36s. The distal nozzle shaft end 37e is fixed to the nozzle coupling plate 36 by rivets. The distal coupling plate end 36e is located on the rear surface 32b2 of the flange. The distal coupling plate end 36e is fitted into the connection point 35J (see Fig. 2) In particular, the distal coupling plate end 36e is arranged between a pair of the raised sections 35J1. The distal coupling plate end 36e is not fixed to the pair of raised sections 35J1. The nozzle coupling plate 36 is not fixed to the drive ring 35.

[0038] As described above, the nozzle shaft 37 is fixed to the nozzle guide vane 34. The nozzle coupling plate 36 is fixed to the nozzle shaft 37. The nozzle guide vane 34, the nozzle shaft 37, and the nozzle coupling plate 36 can be considered the nozzle guide vane assembly 300, which is a single component.

[0039] The nozzle coupling plate 36 pivots about the nozzle axis NX according to the rotational position of the drive ring 35 relative to the nozzle ring 32. The nozzle shaft 37 rotates about the nozzle axis NX according to the pivoting of the nozzle coupling plate 36. The nozzle guide vane 34, which is fixed to the nozzle shaft 37, pivots about the nozzle axis NX according to the pivoting of the nozzle coupling plate 36.

[0040] However, the nozzle guide vane assembly 300 can move in a manner different from the above. There are small gaps between the nozzle guide vane assembly 300 and other components located next to it. The nozzle guide vane assembly 300 can move relative to the other adjacent components through these gaps. The nozzle guide vane assembly 300 can be subjected not only to a force from the drive ring 35, but also to an unintended external force. For example, the nozzle guide vane assembly 300 is subjected to an external force caused by exhaust gas pulsations via the nozzle guide vane 34. Furthermore, the variable geometry mechanism 30, which incorporates the nozzle guide vane assembly 300, can experience random vibrations or shocks from other devices, such as the internal combustion engine.Random vibrations or shocks acting on the other adjacent components are converted into an unintended external force. The gaps between the components and the effect of this unintended external force can cause unintended movement of the nozzle guide vane assembly 300.

[0041] The unintended movement is exemplified by the wobbling of the nozzle guide vane assembly 300. The unintended movement is not limited to wobbling. Wobbling of the nozzle guide vane assembly 300 refers to the movement of the nozzle shaft 37 as if the nozzle guide vane 37 were shaking its head. This wobbling causes, for example, a phenomenon in which the distal coupling plate end 36e of the nozzle coupling plate 36 irregularly and intermittently contacts the connection point 35J of the drive ring 35.

[0042] The wobble is caused by the presence of the three gaps. First, the first gap C1 between the main guide vane surface 34a of the nozzle guide vane 34 and the back surface 31b of the CC plate 31. Second, the second gap C2 between the back surface 34b of the nozzle guide vane 34 and the main nozzle ring surface 32a. Third, the third gap C3 between the outer circumferential surface 37s of the nozzle shaft and the inner circumferential surface 32s1 of the nozzle shaft hole 32s.

[0043] The unintended movement has been described as being caused by the presence of the gaps and the effect of the external force. The wobble occurs when all of the gaps described above—first gap C1, second gap C2, and third gap C3—are present. The turbine 10 of the first embodiment thus has a mechanism to eliminate at least one of the gaps C1, C2, and C3. The turbine 10 of the first embodiment suppresses the occurrence of the unintended wobble by eliminating the first gap C1. The turbine 10 includes the disc spring 39, which is a preload element, as a component for eliminating the first gap C1.

[0044] “Eliminating the gap” does not require that the entire main surface of the guide vane 34a be in contact with the back surface of the plate 31b. Wobbling occurs when the entire main surface of the guide vane 34a is separated from the back surface of the plate 31b. As long as part of the main surface of the guide vane 34a is in contact with the back surface of the plate 31b, the movement of the nozzle guide vane 34 is limited and wobbling does not occur. The condition in which part of the main surface of the guide vane 34a is in contact with the back surface of the plate 31b is also considered a condition in which the gap is eliminated.

[0045] A "gap" refers to a state in which the components facing each other are not in contact. For example, "the first gap C1 is present" refers to a state in which the main guide vane surface 34a is not in contact with the back plate surface 31b. Accordingly, the state in which part of the main guide vane surface 34a is in contact with the back plate surface 31b is described as in Fig. Figure 3 is not strictly defined as a state in which the first slit C1 is present. The "first slit C1" is used for the convenience of explanation in Fig. 3 indicated.

[0046] As in Fig. 3 and Fig. As shown in Figure 4, the disc spring 39 is arranged between the bearing housing 3 and the variable geometry mechanism 30. The disc spring 39 is annular in shape around the axis of rotation AX. The disc spring 39 is shaped to be inclined from an outer diameter towards an inner diameter. The outer diameter of the disc spring 39 is smaller than the outer diameter of the drive ring 35. One disc spring 39 is provided for each nozzle coupling plate 36.

[0047] The disc spring 39 has a main spring surface 39a and a spring back surface 39b. The main spring surface 39a faces the variable geometry mechanism 30. In particular, the main spring surface 39a faces the drive ring 35, the nozzle coupling plates 36, and the nozzle ring 32. The disc spring 39 is disc-shaped. Accordingly, the disc spring 39 faces all nozzle guide vane units 300 of the variable geometry mechanism 30. One disc spring 39 compresses the multiple nozzle guide vane units 300. Furthermore, the main spring surface 39a faces the drive ring back surface 35b of the drive ring 35. The main spring surface 39a also faces the coupling plate back surfaces 36b of the nozzle coupling plates 36. The main spring surface 39a also faces the body back surface 32b1 of the nozzle ring 32. The main spring surface 39a has a main spring surface outer circumferential section 39a1 and a main spring surface inner circumferential section 39a2.The outer circumferential section 39a1 of the main spring surface is in contact with the nozzle guide vane units 300. In particular, the outer circumferential section 39a1 of the main spring surface is in contact with the coupling plate rear surfaces 36b of the nozzle coupling plates 36. The inner circumferential section 39a2 of the main spring surface is not in contact with the nozzle guide vane units 300. The inner circumferential section 39a2 of the main spring surface is separated from the coupling plate rear surfaces 36b. For example, the inner circumferential section 39a2 of the main spring surface is separated from the distal nozzle shaft ends 37e and faces the distal nozzle shaft ends 37e.

[0048] The spring return surface 39b faces the main bearing housing surface 3a. The spring return surface 39b has an outer circumferential section 39b1 and an inner circumferential section 39b2. The outer circumferential section 39b1 is separated from the main bearing housing surface 3a. The inner circumferential section 39b2 is in contact with the main bearing housing surface 3a.

[0049] The disc spring 39 is arranged between the nozzle coupling plates 36 and the bearing housing 3. The distance from the nozzle coupling plates 36 to the bearing housing 3 is less than the rest length of the disc spring 39. The disc spring 39 is thus compressed in the direction of the axis of rotation AX. The disc spring 39 generates an elastic force as a preload force by being compressed. The elastic force acts on the nozzle coupling plates 36 via a section of the spring's main surface outer circumferential section 39a1, which is in contact with the coupling plate rear surfaces 36b, forming a force point PA.

[0050] When a force is applied to the nozzle guide vane units 300, the nozzle shafts 37 move along an axial direction. The nozzle guide vanes 34 move along the axial direction together with the movement of the nozzle shafts 37. The nozzle guide vanes 34 bear against the CC plate 31, which is a section facing the nozzle guide vanes 34. As a result, the first columns C1 are eliminated.

[0051] The magnitude of the force F is such that it does not restrict the movement required by the nozzle guide vane units 300. Ideally, the magnitude of the force F is such that the main guide vane surfaces 34a of the nozzle guide vanes 34 come into contact with the back surface 31b of the CC plate 31. This is because a frictional force is generated between the main guide vane surfaces 34a and the back surface 31b when the main guide vane surfaces 34a are pressed against the back surface 31b. The frictional force generated by the contact between the main guide vane surfaces 34a and the back surface 31b is permissible if it does not restrict the pivoting of the nozzle guide vane 34, which corresponds to the movement of the drive ring 35. The elastic force can be adjusted to a size such that a contact force acts from the guide vane main surfaces 34a onto the plate back surface 31b.The condition in which a contact force acts from the guide vane main surfaces 34a onto the plate back surface 31b makes it possible to counteract the irregular external force acting on the nozzle guide vanes 34, which is caused by the exhaust gas pulsations. The elastic force can be adjusted based on the magnitude of the expected external force.

[0052] Unlike the application of the elastic force by the disc spring 39, the positions of the components forming the variable geometry mechanism 30 are also involved in eliminating the first column C1 mentioned above. To eliminate the first column C1 by applying the force F to the nozzle coupling plates 36, it is necessary that the guide vane main surfaces 34a can be moved until they are in contact with the plate rear surface 31b. This can be achieved by a relationship satisfied in which the fourth column C4 between the coupling plate main surfaces 36a and the body rear surface 32b1 is larger than the first column C1 between the guide vane main surfaces 34a and the plate rear surface 31b. For example, the fourth column C4 still exists between the coupling plate main surfaces 36a and the body rear surface 32b1 even when the guide vane main surfaces 34a are in contact with the plate rear surface 31b.

[0053] The positions of the force point PA are described in further detail.

[0054] The coupling plate back surface 36b of each of the nozzle coupling plates 36 has a first region S1 and a second region S2. The first region S1 overlaps, when viewed axially along the nozzle axis NX, with a projection region SB of the nozzle guide vane 34. The first region S1 includes the coupling plate base end 36f. The first region S1 is a region located close to the distal nozzle shaft end 37e. The second region S2 is a section of the coupling plate back surface 36b that excludes the first region S1. The second region S2 does not overlap, when viewed axially along the nozzle axis NX, with the projection region SB of the nozzle guide vane 34. The second region S2 is a region located farther from the coupling plate base end 36f of the nozzle coupling plate 36. The second region S2 extends to the distal coupling plate end 36e of the nozzle coupling plate 36. The second region S2 is a region that is far from jet shaft 37.The area of ​​the second region S2 can be larger than the area of ​​the first region S1.

[0055] The force point PA of the disc spring 39 in the first embodiment is positioned in the second region S2 above. The force point PA is positioned in the region furthest from the coupling plate base end 36f in the nozzle coupling plate 36.

[0056] According to the turbine 10 of the first embodiment described above, only rotation about the nozzle axis NX is possible as the movement of the nozzle guide vane unit 300 relative to the nozzle ring 32. Thus, any other movement of the nozzle guide vane units 300, such as unintended wobbling, is suppressed. Accordingly, irregular movement of the nozzle guide vane units 300 relative to the nozzle ring 32 does not occur, even if the nozzle guide vanes 34 are subjected to an irregular external force. The state of the component group forming the variable geometry mechanism 30 can preferably be maintained, so that the state in which the variable geometry mechanism 30 is able to exhibit the desired performance can be preserved. The reliability of the turbine 10, which incorporates the variable geometry mechanism 30, can thus be improved.

[0057] The presence of the CC plate 31 allows for precise adjustment of the distance between the CC plate 31 and the nozzle ring 32. The gaps formed between the nozzle guide vanes 34 and a disc element (CC plate 31 or nozzle ring 32) can also be precisely adjusted. Furthermore, a force capable of suppressing irregular movement of the nozzle guide vanes 34 can be easily applied without restricting their rotation around the nozzle shafts 37.

[0058] Furthermore, the distance from the nozzle ring 32 along the direction of the axis of rotation AX to the nozzle coupling plates 36 (fourth gap C4) is greater than the distance from the nozzle guide vanes 34 along the direction of the axis of rotation AX to the CC plate 31, which faces the nozzle guide vanes 34 (first gap C1). The nozzle guide vanes 34 are in contact with the CC plate 31 by the force F before the nozzle coupling plates 36 contact the nozzle ring 32. The nozzle guide vanes 34 can be reliably brought into contact with the CC plate 31, which is the section facing the nozzle guide vanes 34.

[0059] The force F is applied to each nozzle shaft 37 at a position offset from the nozzle axis NX. In this configuration, the force F is applied by the disc spring 39 to the region furthest from the nozzle shaft 37 (second region S2). The distance from the position on the nozzle coupling plate 36, which is the point of force PA where the force F acts on the section where the nozzle coupling plate 36 is connected to the nozzle shaft 37, is increased. A moment is generated that attempts to tilt the nozzle shaft 37 of the nozzle guide vane assembly 300. Any movement, such as unintentional wobbling, is further suppressed because a frictional force is generated due to contact with the inner circumferential surface 32s1 of the nozzle shaft hole 32s.

[0060] Furthermore, the elimination of the first gap C1 between the nozzle guide vanes 34 and the CC plate 31 produces effects that are different from suppressing wobble.

[0061] As in Fig. As shown in Figure 1, the exhaust gas discharged by the variable geometry mechanism 30 is received by a blade section 12s of the turbine wheel 12. Ideally, the condition of the exhaust gas supplied to the turbine wheel 12 by the variable geometry mechanism 30 is uniform regardless of location. However, due to the configuration of the connecting flow path S in the variable geometry mechanism 30, the condition of the exhaust gas supplied to the turbine wheel 12 can vary depending on location. For example, the first column C1 between the nozzle guide vanes 34 and the CC plate 31 and the second column C2 between the nozzle guide vanes 34 and the nozzle ring 32 influence the condition of the exhaust gas. It is preferable for the first column C1 and the second column C2 to be absent in order to bring the condition of the exhaust gas closer to a favorable state.

[0062] In the first embodiment, the first gaps C1 are eliminated by bringing the nozzle guide vanes 34 into contact with the CC plate 31. However, the second gaps C2 between the nozzle guide vanes 34 and the nozzle ring 32 still remain.

[0063] By focusing on the turbine wheel 12, the exhaust gas flow path is a space enclosed by the turbine wheel 12 and the turbine housing 11. A small gap C5 is formed in the section where the turbine wheel 12 faces the turbine housing 11. The gap C5 tends to influence the flow conditions. Accordingly, it is desirable that the exhaust gas, which is close to an ideal state, is directed to the section where the gap C5 is present. The section where the turbine wheel 12 and the turbine housing 11 face each other is positioned downstream of the section where the nozzle guide vanes 34 and the CC plate 31 face each other. The first gaps C1 are eliminated in the section where the nozzle guide vanes 34 and the CC plate 31 face each other. Thus, the turbulence of the exhaust gas tends to be suppressed.The exhaust gas, in which turbulence is suppressed, is fed to the section where the nozzle guide vanes 34 and the CC plate 31 face each other. As a result, an exhaust gas in a near-ideal state is supplied to the turbine wheel 12. Accordingly, the energy of the exhaust gas can be efficiently recovered by the turbine wheel 12, which contributes to improving the performance of the turbocharger 1.

[0064] Fig. Figure 5 is a sectional view of a main part of a turbine 10A of a second embodiment. Fig. Figure 6 is a top view of a preload element of the turbine 10A of the second embodiment. The turbine 10A of the second embodiment differs from the turbine 10 of the first embodiment in that it has a heat shielding plate 41 instead of the disc spring 39.

[0065] The heat shielding plate 41 blocks heat on the side of the turbine housing 11. The heat shielding plate 41 also functions as the disc spring 39. The heat shielding plate 41 presses the nozzle guide vane units 300. The heat shielding plate 41 has a disc section 42 and a spring section 43.

[0066] The disc section 42 has a disc-like shape around the axis of rotation AX. The disc section 42 is located on the side of the nozzle ring 32 that is closer to the bearing housing 3. The disc section 42 is separated from the nozzle coupling plates 36 in the axial direction along the axis of rotation AX. The disc section 42 has a main disc surface 42a and a rear disc surface 42b. The main disc surface 42a faces the nozzle coupling plates 36. The rear disc surface 42b may be in contact with the bearing housing 3. The disc section 42 suppresses the temperature rise of the bearing housing 3.

[0067] The spring section 43 projects from the main disk surface 42a. The disk section 42 and the spring section 43 are formed in one piece. The spring section 43 is ring-shaped around the axis of rotation AX. The cross-sectional shape of the spring section 43 is not restricted, as long as it is a shape that can generate a restoring force by being compressed. Similar to the disc spring 39 of the first embodiment, a spring section 43 is in contact with the plurality of nozzle coupling plates 36. The spring section 43 allows the position of the force point PA to be adjusted as desired by means of a diameter of the spring section 43 that is appropriately set. In the case of the Fig. In example 5, the position at which the spring section 43 is in contact with the nozzle coupling plates 36 (position of the force point PA) is in the second region S2. If, for example, the diameter of the spring section 43 is set smaller than that which is in Fig. If 5 is the position of the force point PA, it can be set in the first region S1.

[0068] Similar to the disc spring 39 of the first embodiment, the heat shielding plate 41 is in contact with the nozzle coupling plates 36 and exerts a force on the nozzle coupling plates 36. The turbine 10A of the second embodiment produces effects similar to those of the turbine 10 of the first embodiment.

[0069] Fig. Figure 7 is a sectional view showing a main part of a turbine 10B of a third embodiment. Fig. Figure 8 is a top view showing a preload element of the turbine 10B of the third embodiment. In the first embodiment, the disc spring 39 is shown as an example of the preload element. In the first embodiment, a configuration in which a disc spring 39 presses the plurality of nozzle guide vane units 300 is shown by way of example. However, the preload element is not limited to the disc spring 39. Furthermore, the preload element is not limited to a configuration in which a preload element presses the plurality of nozzle guide vane units 300. In the third embodiment, a helical spring 51 is shown as an example of the preload element. In addition, a configuration in which a helical spring 51 (preload element) presses a nozzle guide vane unit 300 is shown by way of example in the third embodiment.

[0070] The helical spring 51 is arranged between the nozzle coupling plate 36 and the bearing housing 3. Furthermore, the helical spring 51 is arranged coaxially with the nozzle shaft 37. One helical spring 51 is provided for each nozzle coupling plate 36 (see Fig. 8).

[0071] In particular, a distal spring end 51a of the helical spring 51 is in contact with the coupling plate rear surface 36b of the nozzle coupling plate 36. The distance from the coupling plate rear surface 36b to the bearing housing main surface 3a can be easily and precisely adjusted, since the coupling plate rear surface 36b is a flat surface. The distance from the coupling plate rear surface 36b to the bearing housing main surface 3a influences the magnitude of the force F generated by the helical spring 51. If the distance from the coupling plate rear surface 36b to the bearing housing main surface 3a can be precisely adjusted, the magnitude of the force F generated by the helical spring 51 can also be precisely adjusted. A rear spring end 51b of the helical spring 51 is in contact with the bearing housing main surface 3a.

[0072] Furthermore, the distal spring end 51a is arranged to surround the distal nozzle shaft end 37e. The distal nozzle shaft end 37e is located within the helical spring 51. It can be said that the distal spring end 51a is in contact with the first region S1 of the nozzle coupling plate 36. It can be said that a line of action of the force F generated by the helical spring 51 corresponds to the nozzle axis NX. If the line of action of the force F does not correspond to the nozzle axis NX, a moment is generated corresponding to a distance from the line of action to the nozzle axis NX. The moment corresponding to the distance from the line of action to the nozzle axis NX tilts the nozzle shaft 37 (see Fig. 3) so that an effect is generated to press the outer circumferential surface 37s of the nozzle shaft against the inner circumferential surface 32s1 of the nozzle shaft orifice 32s. If, on the other hand, the line of action of the force F corresponds to the nozzle axis NX, no moment is generated to tilt the nozzle shaft 37. Accordingly, only a force is exerted that moves the nozzle guide vane assembly 300 in the direction of the nozzle axis NX.

[0073] In the third embodiment of turbine 10B, the force is applied by the coil spring 51 to a region near the nozzle shaft 37. Accordingly, tilting of the nozzle shaft 37 relative to the nozzle axis NX is suppressed by the force F. Contact of the nozzle shaft 37 with the inner circumferential surface 32s1 of the nozzle shaft bore 32s can be prevented.

[0074] In the first embodiment, a configuration is used to eliminate the first gaps C1 in order to suppress wobble. Suppression of wobble can also be achieved by eliminating the third gaps C3 between the outer circumferential surfaces 37s of the nozzle shaft and the inner circumferential surfaces 32s1 of the nozzle shaft holes 32s. In the fourth embodiment, a preload element is shown by way of example that eliminates the third gap C3.

[0075] Fig. Figure 9 is a sectional view showing a main part of a turbine 10C of a fourth embodiment. Fig. Figure 10 is a top view showing a preload element of the turbine 10C of the fourth embodiment. The turbine 10C of the fourth embodiment differs from the turbine 10 of the first embodiment in that it has a ring spring 61 instead of the disc spring 39.

[0076] The ring spring 61 is a spring element. For example, a piston ring or a seal can be used as the preload element. The ring spring 61 is annular around the axis of rotation AX, with a section cut out along its circumference. Thus, the ring spring 61 is C-shaped in a top view. In the cut-out section of the ring spring 61, a pair of spring ends 61e1, 61e2 are formed, separated from each other. When deformed to bring a first spring end 61e1 closer to a second spring end 61e2, the diameter of the ring spring 61 decreases. A restoring force is generated in the ring spring 61 to return it to its original diameter. The direction of this restoring force can be considered to be the same as the direction of the diameter of the ring spring 61.

[0077] The ring spring 61 has an outer circumferential surface 61a and an inner circumferential surface 61b. The outer circumferential surface 61a is in contact with the coupling plate base ends 36f of the nozzle coupling plates 36. In particular, the outer circumferential surface 61a is in contact with the base end faces of the coupling plate base ends 36f. Furthermore, the ring spring 61 is C-shaped in a top view. Accordingly, a ring spring 61 presses the plurality of nozzle coupling plates 36 outwards in the radial direction. The inner circumferential surface 61b is arranged in a spring groove 3g, which is provided in the bearing housing 3. The spring groove 3g is provided in an outer circumferential surface of a fitting part 3s, which projects from the main bearing housing surface 3a towards the turbine housing 11. This configuration allows for an expanding or contracting deformation of the diameter of the ring spring 61. Furthermore, the movement of the ring spring 61 in the direction of the axis of rotation AX can be limited.Accordingly, the position of the ring spring 61 can be prevented from being displaced in the direction of the axis of rotation AX, so that the state in which the nozzle coupling plates 36 are pressed can be maintained.

[0078] The ring spring 61 is in contact with the nozzle coupling plates 36 and applies a force in the radial direction of the nozzle shafts 37. When a radial force is applied to the nozzle coupling plates 36, the nozzle coupling plates 36 move along the radial direction. As the nozzle coupling plates 36 move, the nozzle shafts 37, which are attached to the coupling plate base ends 36f, also move along the radial direction. The nozzle shafts 37 then bear against the inner circumferential surfaces 32s1 of the nozzle shaft holes 32s of the nozzle ring 32. The third gap C3 in the radial direction between the nozzle guide vanes 34 and the nozzle ring 32 is eliminated.

[0079] According to the fourth embodiment of turbine 10C, only rotation about the nozzle shaft 37 is possible as the movement of the nozzle guide vane unit 300 relative to the nozzle ring 32, and any other movement, such as unintended wobbling, is suppressed. Accordingly, irregular movement of the nozzle guide vane units 300 does not occur, even if the nozzle guide vanes 34 are subjected to an irregular force. The state of the component group forming the variable geometry mechanism 30 can preferably be maintained, thus preserving the state in which the variable geometry mechanism 30 is able to exhibit the desired performance. The reliability of turbine 10C, which incorporates the variable geometry mechanism 30, can therefore be improved.

[0080] The present invention is not limited to the embodiments described above, and various variations, as described below, are possible without deviating from the present invention as defined by the claims. For example, one aspect of the preload element is not limited to the aspects described in the embodiments.

[0081] Fig. Figure 11 is a sectional view showing a main part of a turbine 10D of a first variation. The turbine 10D of the first variation differs from the turbine 10B of the third embodiment in that it has springs 71 instead of helical springs 51.

[0082] The spring 71 can be, for example, a coil spring or a disc spring. The spring 71 is arranged between the nozzle ring 32 and the nozzle coupling plate 36. In particular, the spring 71 is arranged between the rear body surface 32b1 of the nozzle ring 32 and the main coupling plate surface 36a of the nozzle coupling plate 36. Furthermore, the spring 71 is arranged substantially coaxially with the nozzle shaft 37. One spring 71 is provided for each nozzle coupling plate 36. For example, in a case where the spring 71 is a coil spring, the nozzle shaft 37 is inserted within the coil spring.

[0083] The spring 71 is in contact with the nozzle coupling plate 36 and applies the force F in the direction of the nozzle axis NX. The direction of the force F generated by the spring 71 is opposite to the direction of the force F generated by the helical spring 51 of the third embodiment. When the force F is applied axially to the nozzle coupling plate 36, the nozzle coupling plate 36 moves along the nozzle axis NX. The nozzle coupling plate 36 is separated from the nozzle ring 32. When the nozzle coupling plate 36 is separated from the nozzle ring 32, the nozzle shaft 37, which is attached to the coupling plate base end 36f of the nozzle coupling plate 36, moves along the axial direction. The nozzle guide vane 34, which is attached to the nozzle shaft base end 37f, moves along the nozzle axis NX. The guide vane rear surface 34b of the nozzle guide vane 34 is in contact with the nozzle ring main surface 32a.The second gap C2 between the nozzle guide vane 34 and the nozzle ring 32 has been eliminated.

[0084] Similar to the turbine 10 of the first embodiment, the turbine 10D of the first variation is able to suppress a movement, such as an unintentional wobble.

[0085] Fig. Figure 12 is a sectional view showing a main part of a turbine 10E of a second variation. The turbine 10E of the second variation differs from the turbine 10B of the third embodiment in that it further comprises a heat shielding plate 81. The helical spring 51 is arranged between the nozzle coupling plate 36 and the heat shielding plate 81. As shown in Fig. As shown in Figure 12, the helical spring 51 is in contact with the nozzle coupling plate 36. The other end of the helical spring 51 is in contact with the heat shielding plate 81. The helical spring 51 is in contact with a first region of the nozzle coupling plate 36 and applies the force F in the direction of the nozzle axis NX. The turbine 10E of the second variation produces effects similar to those of the turbine 10B of the third embodiment.

[0086] Fig. Figure 13 is a sectional view of a turbocharger 1F having a turbine 10F of a third variation. For example, in the first embodiment, it is described that the section facing the nozzle guide vane 34 is the CC plate 31. As in Fig. As shown in Figure 13, the section facing the nozzle guide vane 34 can be a turbine housing 11A. The turbine housing 11A has a flow path surface 11s facing an end face of the nozzle guide vane 34, opposite an end face on which the nozzle shaft 37 is located. The nozzle guide vane 34 can be in contact with the flow path surface 11s of the turbine housing 11A. Such a configuration eliminates the need for a CC plate 31, which is a separate component with which the nozzle guide vane 34 comes into contact. Accordingly, the turbine 10 can have a simple configuration.

[0087] Fig. Figure 14 is a sectional view showing a main part of a variable geometry mechanism 30G of a turbine 10G of a fourth variation. For example, in the first embodiment, a configuration is shown by way of example in which the nozzle guide vane 34 has the nozzle shaft 37, which is provided on the guide vane trailing surface 34b. The support configuration of the first embodiment is a so-called overhang type. As in Fig.As shown in Figure 14, the support structure of a nozzle guide vane 34G can be a so-called over-span mounting type. The nozzle guide vane 34G of the fourth variation can also have a nozzle shaft 37K on the main guide vane surface 34a, which is opposite to the guide vane rear surface 34b, on which the nozzle shaft 37 is provided. The nozzle shaft 37K is coaxial with the nozzle shaft 37. The nozzle shaft 37K is inserted in a hole 31q formed in a CC plate 31G. The nozzle guide vane 34 is supported by the nozzle shafts 37 and 37K on both the side of the CC plate 31G and the side of the nozzle ring 32. Reference symbol list 10, 10A, 10B, 10C, 10D, 10E, 10F, 10G turbine 11 Turbine housing (casing) 11R Inlet port 11s flow path area 12 Turbine wheel 30, 30G Variable Geometry Mechanism 31 CC plate (disc element) 32 nozzle ring 32b1 Back of body 32s1 Inner circumferential area 34, 34G Nozzle guide vane 36 nozzle coupling plate 37 Nozzle shaft 39 Disc spring (preload element) 61 Ring spring (preload element) 300 nozzle guide vane unit F force (preload force) S1 First Region S2 Second Region

Claims

[1] Turbine (10, 10A) with: a turbine wheel (12); a turbine housing (11) which has a flow path through which a gas flows and is taken in by an inlet port; a bearing housing (3); a variable geometry mechanism (30) arranged within the turbine housing (11) and configured to receive the gas from the flow path and direct the gas to the turbine wheel (12), wherein the variable geometry mechanism (30) comprises a disk-shaped nozzle ring (32) having a main surface (32a) facing the turbine wheel (12) and a rear surface (32b), and nozzle guide vane units (300) each comprising a nozzle guide vane (34) arranged on one side of the main surface (32a) of the nozzle ring (32), a nozzle shaft (37) extending from the nozzle guide vane (34) and passing through the nozzle ring (32), and a nozzle coupling plate (36) arranged on one side of the rear surface (32b) of the nozzle ring (32) and connected to a distal end of the nozzle shaft (37) is connected; and a preload element (39, 41) which is arranged between the nozzle coupling plate (36) and the bearing housing (3) is in contact with a coupling plate rear surface (36b) of the nozzle coupling plate (36) and applies a preload force in an axial direction of the nozzle shaft (37), wherein the nozzle guide vane (34) is in contact with a section facing the nozzle guide vane (34) due to the preload force, wherein the nozzle coupling plate (36) comprises a first region (S1) which, when viewed in the axial direction, overlaps with the nozzle guide vane (34), and a second region (S2) that does not overlap with the nozzle guide vane (34), and wherein a section in which the preloading element (39, 41) is in contact with the nozzle coupling plate (36) is positioned in the second region (S2). [2] Turbine (10, 10A) according to claim 1, wherein the variable geometry mechanism (30) further comprises a disk element (31) has, which together with the nozzle ring (32) interposed the nozzle guide vane (34), and wherein the section facing the nozzle guide vane (34) is the disk element (31). [3] Turbine (10, 10A) according to claim 1, wherein the turbine housing (11) has a flow path surface which faces an end surface of the nozzle guide vane (34) which is opposite an end surface on which the nozzle shaft (37) is provided, and wherein the section facing the nozzle guide vane (34) is the flow path surface of the turbine casing (11). [4] Turbine (10, 10A) according to one of claims 1 to 3, wherein a distance from the nozzle ring (32) along the axial direction to the nozzle coupling plate (36) is greater than a distance from the nozzle guide vane (34) along the axial direction to the section facing the nozzle guide vane (34). [5] Turbine (10C) with: a turbine wheel (12); a turbine housing (11) which has a flow path through which a gas flows and is taken in by an inlet port; a variable geometry mechanism (30) located inside the turbine housing (11) is arranged and configured to receive the gas from the flow path and guide the gas to the turbine wheel (12), wherein the variable geometry mechanism (30) comprises a disk-shaped nozzle ring (32) having a main surface (32a) facing the turbine wheel (12) and a rear surface (32b), and nozzle guide vane units (300) each comprising a nozzle guide vane (34) arranged on one side of the main surface (32a) of the nozzle ring (32), a nozzle shaft (37) extending from the nozzle guide vane (34) and passing through the nozzle ring (32), and a nozzle coupling plate (36) arranged on one side of the rear surface (32b) of the nozzle ring (32) and connected to a distal end of the nozzle shaft (37); and a preload element (61) which is in contact with the nozzle guide vane units (300) and applies a preload force in a radial direction of the nozzle shaft (37), wherein the nozzle shaft (37) rests against an inner circumferential surface (32s1) of a through-hole of the nozzle ring (32) and wherein the preloading element (61) is located radially inwards of the nozzle coupling plate (36) in order to contact a coupling plate base end (36f). [6] Turbocharger (1) with the turbine (10, 10A, 10C) according to any one of claims 1 to 5.

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