Variable displacement supercharger

Abstract

This variable displacement supercharger comprises a turbine impeller, a turbine housing that houses the turbine impeller and includes a scroll flow passage provided around the turbine impeller, a variable nozzle mechanism that adjusts an opening degree of a nozzle flow passage by which the scroll flow passage and the turbine impeller communicate, and an actuator connected to the variable nozzle mechanism. The variable nozzle mechanism is provided with a drive lever located outside the turbine housing and a link pin connected to the drive lever. The actuator is provided with a drive rod rotatably connected to the link pin, the drive rod has a resin part containing a resin material, and the drive lever is located between the turbine housing and the drive rod.

Description

Variable displacement supercharger

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

[0002] Patent Document 1 discloses a variable displacement supercharger. The variable displacement supercharger includes a turbine housing that houses a turbine impeller and a bearing housing connected to the turbine housing. A nozzle flow path that communicates from the scroll flow path to the turbine impeller is provided between the turbine housing and the bearing housing. The variable displacement supercharger includes a variable stator mechanism that adjusts the communication opening degree of the nozzle flow path. The variable stator mechanism includes a nozzle vane disposed in the nozzle flow path, a nozzle ring that supports the nozzle vane, and a drive ring that rotates the nozzle vane. The drive ring is connected to a drive lever via a drive shaft. The drive lever is connected to a drive rod of an actuator, swings by the movement of the drive rod, and rotates the drive ring.

[0003] Japanese Patent Application Laid-Open No. 2014-181589

[0004] The drive rod of the actuator is made of metal and is disposed outside rather than inside the turbine housing or the bearing housing, so there remains a problem from the viewpoint of corrosion resistance.

[0005] Therefore, the present disclosure provides a variable displacement supercharger capable of improving corrosion resistance.

[0006] The variable displacement supercharger according to one aspect of the present disclosure includes a turbine impeller, a turbine housing that houses the turbine impeller and has a scroll flow path provided around the turbine impeller, a variable nozzle mechanism that adjusts the opening degree of a nozzle flow path that communicates between the scroll flow path and the turbine impeller, and an actuator connected to the variable nozzle mechanism. The variable nozzle mechanism includes a drive lever disposed outside the turbine housing and a link pin connected to the drive lever. The actuator includes a drive rod rotatably connected to the link pin. The drive rod has a resin portion containing a resin material, and the drive lever is disposed between the turbine housing and the drive rod.

[0007] In a variable displacement turbocharger, the actuator's drive rod has a resin component, which enhances its corrosion resistance. Furthermore, since the drive lever is positioned between the turbine housing and the drive rod, some of the heat transmitted from the turbine housing is blocked by the drive lever, preventing it from reaching the drive rod. As a result, deterioration of the resin component due to heat from the turbine housing can be suppressed. Additionally, the presence of the resin component allows for weight reduction of the drive rod. The resin component may be part of the drive rod, or it may constitute the entire drive rod.

[0008] In some embodiments, the variable nozzle mechanism may include a nozzle vane rotatably arranged within the nozzle flow path, and a drive ring connected to the nozzle vane and rotating the nozzle vane by the swing of a drive lever. The drive lever may be located between the resin part and the turbine housing. The opening of the nozzle flow path is adjusted by the rotation of the nozzle vane. The drive ring rotates the nozzle vane by the swing of the drive lever. The drive lever is located between the resin part and the turbine housing, which reduces the effect of heat from the turbine housing on the resin part.

[0009] In some embodiments, the link pin comprises a first shaft portion connected to a drive lever and a second shaft portion connected to a drive rod, and the drive rod may include a joint portion connected to the second shaft portion. The joint portion has an inner circumferential surface that slides against the second shaft portion, and the shaft diameter of the second shaft portion may be larger than the shaft diameter of the first shaft portion. When the link pin wears down due to sliding contact with the inner circumferential surface of the joint portion, a shift in the center position of the link pin occurs. This shift in center position becomes smaller as the shaft diameter of the link pin increases. In the above embodiments, since the shaft diameter of the second shaft portion is larger than that of the first shaft portion, the shift in center position due to wear is smaller compared to the case where the shaft diameters are the same as those of the first shaft portion. Also, some of the heat transmitted from the drive lever to the drive rod is transmitted via the link pin. The first shaft portion of the link pin connected to the drive lever has a smaller shaft diameter than the second shaft portion. Therefore, it becomes easier to suppress the amount of heat transmitted from the drive lever to the link pin.

[0010] In some embodiments, the resin part includes a joint connected to a link pin, and the joint may have an inner circumferential surface that slides against the link pin. When the link pin or the joint wears down, a misalignment occurs in the center position of the link pin. The joint of the resin part has a lower coefficient of friction than, for example, a metal joint. As a result, wear between the link pin and the inner circumferential surface of the joint can be reduced. Also, for example, if the link pin is made of metal, which has higher wear resistance than the resin part, the inner circumferential surface of the joint of the resin part will wear down preferentially, preventing wear on the link pin. The misalignment caused by wear on the joint is smaller than the misalignment caused by wear on the link pin. Therefore, by preventing wear on the link pin, the misalignment of the link pin is reduced, and the power transmitted from the drive rod to the drive lever is maintained stably. In addition, the drive rod is made lighter by including the resin part, and vibrations when the drive rod transmits power to the drive lever are reduced. By reducing vibrations, wear on the joint connected to the link pin is suppressed.

[0011] In some embodiments, the link pin may comprise a pin shaft connected to the drive lever and the drive rod, and a collar portion extending radially from the pin shaft and positioned between the drive lever and the drive rod. The collar portion can prevent some of the heat from being transmitted from the drive lever to the drive rod.

[0012] In some embodiments, the drive rod comprises a joint connected to a link pin, and the drive lever comprises a thermal protection portion shaped to conform to the outer shape of the joint, the thermal protection portion may cover at least a portion of the joint in the axial direction of the link pin. The thermal protection portion covers at least a portion of the joint and blocks some of the heat transmitted to the joint by radiation from the turbine housing.

[0013] In some embodiments, the drive rod comprises a joint connected to a link pin, and the drive lever comprises a thermal protection portion having an outer diameter equal to or greater than the outer diameter of the joint, the thermal protection portion may cover at least a portion of the joint in the axial direction of the link pin. The thermal protection portion covers at least a portion of the joint and blocks some of the heat transmitted to the joint by radiation from the turbine housing.

[0014] In some embodiments, the turbine housing may include a bearing housing connected to the turbine housing and forming a nozzle passage between it and the turbine housing. The turbine housing has a spigot joint into which the bearing housing fits and connects, and the link pin may be positioned radially outward from the spigot joint with respect to the rotation axis of the turbine impeller. Hot gases within the turbine housing may leak out from the spigot joint. Since the link pin is positioned radially outward from the spigot joint, the effect of heat transfer from the hot gases to the link pin is reduced, and as a result, the effect of heat transfer to the joint via the link pin can be reduced.

[0015] In some embodiments, the drive rod may be positioned radially outward from the spigot portion, with respect to the rotation axis of the turbine blade. This reduces the effect of heat transfer from the high-temperature gas to the drive rod.

[0016] In some embodiments, the turbine housing may have an end face facing the drive lever, and the link pin may be positioned radially outward from the end face of the turbine housing, with respect to the rotation axis of the turbine impeller. This reduces the effect of heat transmitted from the end face of the turbine housing to the link pin.

[0017] In some embodiments, the drive rod may be positioned radially outward relative to the end face of the turbine housing. This reduces the effect of heat transmitted from the end face of the turbine housing to the drive rod.

[0018] According to this disclosure, the corrosion resistance of variable displacement turbochargers can be improved.

[0019] Figure 1 is a cross-sectional view showing a variable displacement turbocharger of this embodiment. Figure 2 is a perspective view showing a part of the variable displacement turbocharger. Figure 3 is a front view of a drive lever and drive rod according to one example, viewed from the direction of the rotation axis. Figure 4 is a cross-sectional view showing a part of the variable nozzle mechanism and the drive rod. Figure 5 is an exploded perspective view showing the vane assembly and drive link section. Figure 6 is a front view of the drive link section viewed from the direction of the rotation axis. Figure 7 is a front view of a drive lever and drive rod according to one example, viewed from the direction of the rotation axis. Figure 8(a) is a schematic cross-sectional view showing the connection state of the resin joint section and link pin before wear. Figure 8(b) is a schematic cross-sectional view showing the wear state of the joint section shown in Figure 8(a). Figure 9(a) is a schematic cross-sectional view showing the connection state of the metal joint section and link pin before wear. Figure 9(b) is a schematic cross-sectional view showing the wear state of the link pin and joint section shown in Figure 9(a).

[0020] The embodiments of this disclosure will be described in detail below with reference to the drawings. Figure 1 is a cross-sectional view including the rotation axis of a variable displacement turbocharger. The variable displacement turbocharger (hereinafter referred to as turbocharger 1) is applied, for example, to internal combustion engines of ships and vehicles.

[0021] As shown in Figure 1, the supercharger 1 comprises a turbine 2 and a compressor 3. The turbine 2 comprises a turbine housing 4 and a turbine impeller 6 housed in the turbine housing 4. The turbine housing 4 has a scroll passage 16 provided around the turbine impeller 6. The compressor 3 comprises a compressor housing 5 and a compressor impeller 7 housed in the compressor housing 5. The compressor housing 5 has a scroll passage 17 provided around the compressor impeller 7.

[0022] The turbine impeller 6 is mounted at one end of the rotating shaft 14, and the compressor impeller 7 is mounted at the other end of the rotating shaft 14. A bearing housing 13 is provided between the turbine housing 4 and the compressor housing 5. The rotating shaft 14 is rotatably supported by the bearing housing 13 via a bearing 15. The rotating shaft 14, the turbine impeller 6, and the compressor impeller 7 rotate as a single rotating body around the axis of rotation H. The turbine housing 4 is provided with a spigot portion 4a. The bearing housing 13 is mounted so as to fit inside the spigot portion 4a (see Figure 4).

[0023] The turbine housing 4 is provided with an exhaust gas inlet and an exhaust gas outlet 10. The exhaust gas inlet is fluidly connected (communicated) with the scroll passage 16. Communication means, for example, that they are fluidly coupled. A nozzle passage 18 is provided between the bearing housing 13 and the turbine housing 4. The nozzle passage 18 is arranged around the turbine impeller 6 and is provided between the scroll passage 16 and the turbine impeller 6. The nozzle passage 18 communicates the scroll passage 16 and the turbine impeller 6, and forms a passage from the scroll passage 16 to the turbine impeller 6. Exhaust gas discharged from the internal combustion engine flows into the turbine housing 4, for example, through the exhaust gas inlet. The exhaust gas that has flowed into the turbine housing 4 flows into the turbine impeller 6 through the scroll passage 16 and the nozzle passage 18, causing the turbine impeller 6 to rotate. After that, the exhaust gas flows out of the turbine housing 4 through the exhaust gas outlet 10.

[0024] The compressor housing 5 is provided with an intake port 9 and a discharge port. As the turbine impeller 6 rotates as described above, the compressor impeller 7 rotates via the rotating shaft 14. The rotating compressor impeller 7 draws in outside air through the intake port 9. This air is compressed as it passes through the compressor impeller 7 and the scroll passage 17, and is discharged from the discharge port. The compressed air discharged from the discharge port is supplied to the internal combustion engine mentioned above.

[0025] The turbine 2 is equipped with a variable nozzle mechanism 20 (variable nozzle assembly). The variable nozzle mechanism 20 is equipped with a plurality of movable nozzle vanes 21. In the following description, when we simply refer to the "axial direction," "radial direction," and "circumferential direction," we mean the rotational axis direction (rotational axis H direction), rotational radial direction, and rotational circumferential direction, respectively, of the turbine impeller 6. In addition, in the rotational axis H direction, the compressor side of the supercharger 1 (right side in Figure 1) may simply be referred to as the "compressor side."

[0026] Multiple nozzle vanes 21 are arranged within the nozzle flow path 18. The multiple nozzle vanes 21 are arranged at roughly equal intervals on a circumference centered on the rotation axis H. Each nozzle vane 21 rotates synchronously around an axis parallel to the rotation axis H. As the multiple nozzle vanes 21 rotate, the gaps between adjacent nozzle vanes 21 expand and contract, adjusting the opening of the nozzle flow path 18.

[0027] The variable nozzle mechanism 20 rotates the nozzle vane 21 to adjust the opening of the nozzle flow path 18. The variable nozzle mechanism 20 comprises a vane assembly 22, a drive link section 25 (link assembly), and a drive lever 26. The drive link section 25 is located inside the turbine housing 4 and the bearing housing 13. The drive lever 26 is located outside the turbine housing 4 and the bearing housing 13. The drive lever 26 is connected to the drive link section 25 via a drive shaft 39 and transmits power from the actuator 40 to the drive link section 25.

[0028] As shown in Figures 5 and 6, the vane assembly 22 has a plurality of nozzle vanes 21 and two nozzle rings 23 and 24 that sandwich the plurality of nozzle vanes 21 in the axial direction. The first nozzle ring 23 and the second nozzle ring 24 are arranged in the axial direction. The first nozzle ring 23 is positioned closer to the compressor than the second nozzle ring 24. The first nozzle ring 23 and the second nozzle ring 24 each form a ring shape centered on the axis of rotation H and are arranged to surround the turbine impeller 6 in the circumferential direction. The region sandwiched in the axial direction by the first nozzle ring 23 and the second nozzle ring 24 forms a nozzle flow path 18. The first nozzle ring 23 and the second nozzle ring 24 are connected in the axial direction via a plurality of spacer pins 29. The axial dimensional accuracy of the nozzle flow path 18 is ensured by manufacturing the spacer pins 29 with high precision. The nozzle vanes 21 are rotatably supported by a double-support system, but a single-support system may also be used.

[0029] The first nozzle ring 23 is provided with a plurality of bearing holes 31 that penetrate in the axial direction. The rotation axis 21a of each nozzle vane 21 is rotatably inserted through each bearing hole 31. The plurality of nozzle vanes 21 may be arranged at equal intervals on the circumference or at unequal intervals.

[0030] The drive link section 25 is housed in the space between the first nozzle ring 23 and the bearing housing 13. The drive link section 25 transmits power received from the external actuator 40 to the nozzle vane 21, thereby rotating the nozzle vane 21.

[0031] The drive link section 25 comprises a drive ring 33, a nozzle link plate 35, and a drive link plate 37. The drive ring 33 is ring-shaped and extends along a circumference centered on the rotation axis H, and is positioned along the compressor-side surface of the first nozzle ring 23. The drive ring 33 is rotatable around the rotation axis H relative to the first nozzle ring 23. Engaging portions 33a, which engage with each nozzle link plate 35, are provided on the drive ring 33 at predetermined intervals in the circumferential direction.

[0032] There are as many nozzle link plates 35 as there are nozzle vanes 21. The nozzle link plates 35 extend radially and have an inner circumferential end on the side closer to the axis of rotation H and an outer circumferential end on the opposite side. The inner circumferential end is attached to the axis of rotation 21a of the nozzle vane 21. The outer circumferential end engages with the engaging portion 33a of the drive ring 33.

[0033] The drive link plate 37 is located in one place and is positioned between a pair of nozzle link plates 35 that are adjacent to each other in the circumferential direction. The drive link plate 37 has an inner circumferential end on the side closer to the rotation axis H and an outer circumferential end on the opposite side. The outer circumferential end engages with the input side engaging portion 33b of the drive ring 33. The inner circumferential end is fixed to the drive shaft 39.

[0034] The drive shaft 39 (see Figure 4) has an inner end 39a fixed to the drive link plate 37 and an outer end 39b on the opposite side. The drive shaft 39 penetrates the bearing housing 13, and the outer end 39b is located outside the turbine housing 4 and the bearing housing 13. The outer end 39b of the drive shaft 39 is fixed to the drive lever 26.

[0035] As shown in Figures 1, 3, and 4, the drive lever 26 is connected to the drive rod 41 of the actuator 40. The actuator 40 drives (oscillates) the drive lever 26 via the drive rod 41. The drive lever 26 rotates the drive link plate 37 around an axis parallel to the rotation axis H via the drive shaft 39. When the drive link plate 37 rotates, the outer peripheral end of the drive link plate 37 pushes the input side engaging portion 33b in the circumferential direction. This causes the drive ring 33 to rotate around the rotation axis H, and each engaging portion 33a of the drive ring 33 pushes the outer peripheral end of each nozzle link plate 35 in the circumferential direction. As a result, each nozzle link plate 35 rotates, and each nozzle vane 21 fixed to each nozzle link plate 35 rotates.

[0036] The drive lever 26 has a base end 26a fixed to the drive shaft 39 and a tip end 26b (oscillating part) that pivots (rotates) around the base end 26a. A link pin 27 is connected to the tip end 26b. The axial direction Ha of the link pin 27 is, for example, parallel to the axial direction of the drive shaft 39. The drive rod 41 of the actuator 40 is rotatably connected to the link pin 27. The drive lever 26 is positioned between the turbine housing 4 and the drive rod 41.

[0037] The drive lever 26 extends outward in the radial direction RD, centered on the rotation axis H (rotation axis 14) of the turbine blade 6. The tip 26b of the drive lever 26 is connected to a link pin 27, and both the tip 26b and the link pin 27 are positioned outside the radial direction RD beyond the spigot portion 4a. Furthermore, the drive lever 26, which traces a predetermined trajectory, is positioned outside the radial direction RD beyond the spigot portion 4a.

[0038] The link pin 27 comprises a pin shaft 27a and a collar portion 27b. The pin shaft 27a is connected to the drive lever 26 and the drive rod 41. The collar portion 27b protrudes from the pin shaft 27a so as to extend radially with respect to the axis of the pin shaft 27a.

[0039] The pin shaft 27a comprises a first shaft portion 27c connected to the drive lever 26 and a second shaft portion 27d connected to the drive rod 41. The first shaft portion 27c is fixed to the drive lever 26, for example, by crimping. The shaft diameter D2 of the second shaft portion 27d is larger than the shaft diameter D1 of the first shaft portion 27c. The shaft diameter D2 of the second shaft portion 27d may be 1.5 times or more the shaft diameter D1 of the first shaft portion 27c, or it may be 2 times or more. Also, the shaft diameter D2 of the second shaft portion 27d may be larger than the shaft diameter D1 of the first shaft portion 27c, but 3 times or less.

[0040] One end 41a of the drive rod 41 (see Figure 2) is connected to the drive unit 45 of the actuator 40. The other end of the drive rod 41 is a joint unit 42 (paired part) connected to a link pin 27. The joint unit 42 has a through hole 42a for receiving the second shaft portion 27d of the link pin 27. The second shaft portion 27d is inserted through the through hole 42a and is in sliding contact with the inner circumferential surface 42b of the through hole 42a. The joint unit 42 is rotatable relative to the second shaft portion 27d. A retaining ring 28 is attached to the second shaft portion 27d to prevent the joint unit 42 from coming off. The retaining ring 28 is mounted in the outer circumferential groove 27f of the second shaft portion 27d. The joint unit 42 is positioned between the retaining ring 28 and the collar unit 27b. The drive rod 41 includes a rod body 44 connected to the joint unit 42. The rod body 44 is positioned between one end 41a and the other end (joint portion 42) of the drive rod 41. The rod body 44 is provided with grooves (weight-reducing cutouts) 43a for weight reduction.

[0041] The actuator 40 moves the drive rod 41, causing the drive lever 26 to swing via the link pin 27. As the drive lever 26 swings, the link pin 27 rotates while sliding against the inner circumferential surface 42b of the joint portion 42. This sliding contact creates friction between the link pin 27 and the joint portion 42, causing wear on both the link pin 27 and the joint portion 42. As the wear on the link pin 27 and the joint portion 42 progresses, the center position of the link pin 27 shifts beyond the allowable range. When the center position of the link pin 27 shifts, the power transmitted from the drive rod 41 to the drive lever 26 may become unstable. Furthermore, if the center position of the link pin 27 shifts significantly, vibration occurs when power is transmitted from the drive rod 41 to the drive lever 26, accelerating wear.

[0042] The deviation of the core position due to the wear of the link pin 27 becomes smaller as the shaft diameter of the link pin 27 is larger. For example, in the link pin 27 shown in FIG. 4, the shaft diameter D2 of the second shaft portion 27d connected to the drive rod 41 is larger than the shaft diameter D1 of the first shaft portion 27c connected to the drive lever 26. Therefore, for example, the deviation of the core position due to wear becomes smaller as compared with the case where the shaft diameter of the shaft portion connected to the drive rod is the same as or smaller than the shaft diameter of the shaft portion connected to the drive lever.

[0043] Also, a part of the heat transmitted from the drive lever 26 to the drive rod 41 is transmitted through the link pin 27. The link pin 27 has a smaller shaft diameter D1 of the first shaft portion 27c fixed to the drive lever 26 than the shaft diameter D2 of the second shaft portion 27d. Therefore, it becomes easier to suppress the amount of heat transmitted from the drive lever 26 to the link pin 27.

[0044] At least a part of the drive rod 41 is a resin part 43. The resin part 43 is a part containing a resin material. The resin part 43 may be a part formed of a composite material (composite) in which another material is combined with the resin. For example, the resin part 43 may be a part formed of CFRP in which carbon fiber is added as a reinforcing material to the resin.

[0045] The drive rod 41 may be partly a resin part 43 or may be entirely a resin part 43. By making at least a part of the drive rod 41 made of resin, the weight can be reduced and the vibration when transmitting power from the drive rod 41 to the drive lever 26 can be reduced. As a result, the wear of the link pin 27 and the joint portion 42 due to vibration can be reduced. Also, by having the resin part 43, the range in which rust occurs can be reduced. As a result, the corrosion resistance of the drive rod 41 can be improved.

[0046] The drive rod 41 shown in FIG. 4 is entirely a resin part 43. The resin part 43 includes a joint portion 42. On the other hand, the drive lever 26 and the link pin 27 are formed of a material having higher wear resistance than the resin part 43. For example, the drive lever 26 and the link pin 27 are made of metal (formed of a metal material).

[0047] As described above, when wear occurs between the joint portion and the link pin, the core position of the link pin is displaced. In order to reduce the wear that occurs between the joint portion and the link pin, for example, it is possible to devise such as changing the joint portion and the link pin to a material with high wear resistance. However, since the joint portion 42 shown in FIG. 4 is a part of the resin portion 43 and the link pin 27 is made of metal, the joint portion 42 is easily worn, and the displacement of the core position of the link pin 27 is reduced by an idea (reverse idea) opposite to the above idea. This operation will be described using FIGS. 8(a), FIGS. 8(b), FIGS. 9(a), and FIGS. 9(b).

[0048] FIG. 8(a) is a cross-sectional view showing a state (static state) before the joint portion 42, which is a part of the resin portion 43, and the metal link pin 27 are worn, and FIG. 8(b) is a cross-sectional view showing a state (worn state) after the joint portion 42 and the link pin 27 shown in FIG. 8(a) are worn. Further, FIG. 9(a) is a cross-sectional view showing the static state of the metal joint portion 142 and the metal link pin 127, and FIG. (b) is a cross-sectional view showing the worn state of the joint portion 142 and the link pin 127 shown in FIG. 9(a).

[0049] Assuming that the amount by which the link pin is worn and shaved is the same as the amount by which the inner peripheral surface of the joint portion is worn and shaved, the influence on the displacement of the core position of the link pin is greater for the wear of the link pin than for the wear of the joint portion.

[0050] Here, for example, as shown in FIG. 9(b), when the metal joint portion 142 and the metal link pin 127 are in sliding contact, wear progresses on both, and a displacement M2 occurs in the core position of the link pin 27. In particular, in the reference example shown in FIG. 9(b), not only the inner peripheral surface 142b of the joint portion 142 but also the link pin 27 is worn. The wear of the link pin 27 directly affects the displacement M2 of the core position of the link pin 27. Therefore, the displacement M2 of the core position due to the wear of the link pin 27 becomes large.

[0051] In contrast, since the joint portion 42 shown in Figure 8(b) is part of the resin portion 43, the coefficient of friction of the joint portion 42 is smaller than that of the metal link pin 27. As a result, wear occurring in both the joint portion 42 and the link pin 27 can be reduced. Furthermore, the joint portion 42 shown in Figure 8(b) has lower wear resistance than the link pin 27. Therefore, the joint portion 42 wears preferentially over the link pin 27, and as a result, wear of the link pin 27 is prevented. By preventing wear of the link pin 27, the misalignment M1 of the core position of the link pin 27 becomes smaller than the misalignment M2 mentioned above.

[0052] Furthermore, as an alternative approach to the above considerations, it is possible to reduce the amplitude of oscillation by shortening the longitudinal dimension of the drive lever, thereby reducing the sliding range between the joint and the link pin and reducing wear between the joint and the link pin. In this approach, for example, it is possible to set the length of the drive lever so that its tip is radially inward from the spigot portion of the turbine housing.

[0053] However, in the drive lever 26 shown in Figure 3, the longitudinal dimension of the drive lever is increased to increase the amplitude of the swing, and as a result, a design has been made to widen the sliding range between the joint portion 42 and the link pin 27. This design is the opposite of the design to narrow the sliding range. By widening the sliding range, the wear points are dispersed, and as a result, the deviation of the core position of the link pin 27 can be reduced. For example, the drive lever 26 protrudes outward in the radial direction RD around the rotation axis H (rotation axis 14) of the turbine impeller 6, and the tip portion 26b connected to the link pin 27 is positioned outside the radial direction RD beyond the spigot portion 4a.

[0054] Next, we will explain the measures taken to improve the heat resistance of the drive rod 41 and the resin part 43. The exhaust gas from the turbine 2 reaches temperatures of 700°C to 800°C, and the turbine housing 4 becomes hot due to the influence of the exhaust gas. As a result, heat tends to accumulate around the turbine housing 4 due to radiation from the turbine housing 4.

[0055] In the supercharger 1 shown in Figures 1 and 4, the drive rod 41 has a resin portion 43, and the resin portion 43 is equipped with a joint portion 42. Here, the drive lever 26 is positioned between the drive rod 41 and the turbine housing 4, taking into consideration the heat resistance of the resin portion 43. The drive lever 26 is also positioned between the resin portion 43 and the turbine housing 4. A portion of the heat transmitted from the turbine housing 4 is blocked by the drive lever 26 and prevented from being transmitted to the drive rod 41. As a result, the effect of heat from the turbine housing 4 on the resin portion 43 can be reduced.

[0056] The link pin 27 includes a collar portion 27b positioned between the drive lever 26 and the drive rod 41. The collar portion 27b is positioned between the tip portion 26b of the drive lever 26 and the joint portion 42 of the drive rod 41. The collar portion 27b can prevent some of the heat from being transmitted from the drive lever 26 to the drive rod 41.

[0057] A link pin 27 is connected to the tip 26b of the drive lever 26. The tip 26b functions as a thermal protection part that covers at least a portion of the joint part 42 in the axial direction Ha of the link pin 27. The outer shape of the tip 26b (see Figure 3) is in line with the outer shape of the joint part 42. The outer shape of the joint part 42 refers to the outer circumference shape as viewed from the axial direction Ha of the link pin 27. The outer shape of the joint part 42 is circular (arc-shaped), for example, except for the connection point that connects to the rod body 44. The outer shape of the joint part 42 may be other shapes such as elliptical or polygonal.

[0058] The outer diameter d1 of the tip portion 26b is the same as, or larger than, the outer diameter d2 of the joint portion 42. For example, if the joint portion 42 or the tip portion 26b is elliptical or polygonal, the outer diameter may vary depending on the location. In this case, for example, the outer diameter d1 of the tip portion 26b may be the maximum outer diameter of the tip portion 26b, and the outer diameter d2 of the joint portion 42 may be the maximum outer diameter of the joint portion 42.

[0059] The tip portion 26b is positioned in the axial direction Ha of the link pin 27 to cover part or all of the joint portion 42. As a result, the tip portion 26b blocks some of the heat transmitted from the turbine housing 4 to the joint portion 42, preventing heat from reaching the joint portion 42.

[0060] The drive lever 26 extends outward in the radial direction RD around the rotation axis 14 of the turbine blade 6. The tip 26b of the drive lever 26 is positioned outside the radial direction RD beyond the spigot portion 4a. The drive lever 26 rotates (oscillates) around the drive shaft 39, for example, and the link pin 27 fixed to the tip 26b of the drive lever 26 also oscillates. When the drive lever 26 is viewed from the axial direction Ha of the link pin 27, the trajectory of the link pin 27 does not intersect the spigot portion 4a. Furthermore, the drive rod 41 connected to the link pin 27 is positioned outside the radial direction RD beyond the spigot portion 4a, and when the drive rod 41 is viewed from the axial direction Ha of the link pin 27, the trajectory of the drive rod 41 does not intersect the spigot portion 4a.

[0061] High-temperature exhaust gas from inside the turbine housing 4 may leak out from the spigot portion 4a. Since the link pin 27 is positioned radially outward RD from the spigot portion 4a, the effect of heat transmitted from the high-temperature exhaust gas to the link pin 27 is suppressed, and as a result, the effect of heat transmitted to the joint portion 42 via the link pin 27 can be reduced. In addition, since the joint portion 42, the resin portion 43, or the entire drive rod 41 is positioned radially outward RD from the spigot portion 4a, the effect of heat transmitted from the high-temperature exhaust gas to the drive rod 41 can be suppressed.

[0062] Figure 7 shows a drive lever 26A and a drive rod 41A connected to the drive lever 26A according to another example. The drive lever 26A shown in Figure 7 is longer than the drive lever 26 shown in Figure 3. As shown in Figure 7, the turbine housing 4 has an end face 4b (hereinafter referred to as the opposing end face) that faces the drive lever 26. In Figure 7, the opposing end face 4b is shown with a stippled (dotted) pattern for convenience. As shown in Figure 7, the tip portion 26b of the drive lever 26A is positioned radially outward RD from the opposing end face 4b, with respect to the rotation axis 14 of the turbine impeller 6. The link pin 27 fixed to the tip portion 26b of the drive lever 26A is positioned radially outward RD from the opposing end face 4b. The drive rod 41A is also positioned radially outward RD from the opposing end face 4b. When viewing the drive lever 26A from the axial direction Ha of the link pin 27, the trajectory of the link pin 27 does not intersect the opposing end face 4b. Furthermore, the drive rod 41A connected to the link pin 27 is positioned radially RD outside the spigot portion 4a, and when viewing the drive rod 41A from the axial direction Ha of the link pin 27, the trajectory of the drive rod 41A does not intersect the opposing end face 4b. Note that the drive lever 26A and drive rod 41A shown in Figure 7 are appropriately applied to the supercharger 1 shown in Figure 1.

[0063] Several additional examples are disclosed below.

[0064] (Additional Example 1) A variable displacement supercharger comprises a turbine impeller, a turbine housing that houses the turbine impeller and has a scroll passage provided around the turbine impeller, a variable nozzle mechanism for adjusting the opening of a nozzle passage communicating between the scroll passage and the turbine impeller, and an actuator connected to the variable nozzle mechanism, wherein the variable nozzle mechanism comprises a drive lever located outside the turbine housing and a link pin connected to the drive lever, the actuator comprises a drive rod rotatably connected to the link pin, the drive rod has a resin portion containing a resin material, and the drive lever is located between the turbine housing and the drive rod.

[0065] (Additional Example 2) The variable nozzle mechanism is a variable displacement supercharger according to the first additional example, comprising a nozzle vane rotatably arranged in the nozzle flow path and a drive ring connected to the nozzle vane and rotating the nozzle vane by the swing of the drive lever, wherein the drive lever is located between the resin part and the turbine housing.

[0066] (Additional Example 3) The link pin comprises a first shaft portion connected to the drive lever and a second shaft portion connected to the drive rod, the drive rod comprises a joint portion connected to the second shaft portion, the joint portion comprises an inner circumferential surface that slides against the second shaft portion, and the shaft diameter of the second shaft portion is larger than the shaft diameter of the first shaft portion, this is a variable displacement supercharger according to Additional Example 1 or Additional Example 2.

[0067] (Additional Example 4) The resin part comprises a joint part connected to the link pin, and the joint part comprises an inner circumferential surface that slides against the link pin, in the variable displacement supercharger described in Additional Example 1.

[0068] (Additional Example 5) The link pin is a variable displacement supercharger according to any one of Additional Examples 1 to 4, comprising a pin shaft connected to the drive lever and the drive rod, and a collar portion that extends radially from the pin shaft and is positioned between the drive lever and the drive rod.

[0069] (Additional Example 6) The variable displacement supercharger according to any one of Additional Examples 1 to 5, wherein the drive rod has a joint portion connected to the link pin, the drive lever has a thermal protection portion shaped to conform to the outer shape of the joint portion, and the thermal protection portion covers at least a part of the joint portion in the axial direction of the link pin.

[0070] (Additional Example 7) The drive rod comprises a joint portion connected to the link pin, the drive lever comprises a thermal protection portion having an outer diameter the same as or larger than the outer diameter of the joint portion, and the thermal protection portion covers at least a part of the joint portion in the axial direction of the link pin, as described in any one of Additional Examples 1 to 5.

[0071] (Additional Example 8) A variable displacement supercharger according to any one of Additional Examples 1 to 7, further comprising a bearing housing connected to the turbine housing and forming the nozzle passage between itself and the turbine housing, wherein the turbine housing has a spigot portion into which the bearing housing fits and connects, and the link pin is positioned radially outward from the spigot portion with respect to the rotation axis of the turbine impeller.

[0072] (Additional Example 9) The drive rod is positioned radially outward from the spigot portion with respect to the rotation axis of the turbine blade, as described in Additional Example 8, in this variable displacement supercharger.

[0073] (Additional Example 10) The turbine housing has an end face facing the drive lever, and the link pin is positioned radially outward from the end face with respect to the rotation axis of the turbine blade, as described in any one of Additional Examples 1 to 7.

[0074] (Additional Example 11) The drive rod is arranged radially outward with respect to the end face, and is a variable displacement supercharger as described in Additional Example 10.

[0075] This disclosure is not limited to the embodiments and examples described above. For example, the resin portion may include parts other than the joint portion of the drive rod. Also, the resin portion may not include the entire joint portion, but rather an annular portion along the inner circumferential surface of the through hole.

[0076] 1 Variable displacement supercharger 4 Turbine housing 4a Splice section 4b Opposing end face 6 Turbine impeller 13 Bearing housing 16 Scroll passage 18 Nozzle passage 20 Variable nozzle mechanism 21 Nozzle vane 26, 26A Drive lever 26b Tip section (thermal protection section) 27 Link pin 27a Pin shaft 27b Collar section 27c First shaft section 27d Second shaft section 33 Drive ring 40 Actuator 41, 41A Drive rod 42 Joint section 42b Inner surface 43 Resin section D2 Shaft diameter D1 Shaft diameter H Rotation axis M2 Misalignment of link pin core M1 Misalignment of link pin core Ha Axial direction d1 Outer diameter of tip section d2 Outer diameter of joint section RD Radial direction

Claims

1. A variable displacement supercharger comprising: a turbine impeller; a turbine housing housing the turbine impeller and having a scroll passage provided around the turbine impeller; a variable nozzle mechanism for adjusting the opening degree of a nozzle passage communicating between the scroll passage and the turbine impeller; and an actuator connected to the variable nozzle mechanism, wherein the variable nozzle mechanism comprises a drive lever located outside the turbine housing and a link pin connected to the drive lever; the actuator comprises a drive rod rotatably connected to the link pin, the drive rod having a resin portion containing a resin material, and the drive lever being located between the turbine housing and the drive rod.

2. The variable nozzle mechanism comprises a nozzle vane rotatably arranged in the nozzle flow path, and a drive ring connected to the nozzle vane and rotating the nozzle vane by the swing of the drive lever, wherein the drive lever is located between the resin part and the turbine housing, the variable displacement supercharger according to claim 1.

3. The variable displacement supercharger according to claim 1, wherein the link pin comprises a first shaft portion connected to the drive lever and a second shaft portion connected to the drive rod, the drive rod comprises a joint portion connected to the second shaft portion, the joint portion comprises an inner circumferential surface that slides against the second shaft portion, and the shaft diameter of the second shaft portion is larger than the shaft diameter of the first shaft portion.

4. The variable displacement supercharger according to claim 1, wherein the resin portion comprises a joint portion connected to the link pin, and the joint portion comprises an inner circumferential surface that slides against the link pin.

5. The variable displacement supercharger according to claim 1, wherein the link pin comprises a pin shaft connected to the drive lever and the drive rod, and a collar portion extending radially from the pin shaft and positioned between the drive lever and the drive rod.

6. The variable displacement supercharger according to claim 1, wherein the drive rod comprises a joint portion connected to the link pin, the drive lever comprises a thermal protection portion shaped to conform to the outer shape of the joint portion, and the thermal protection portion covers at least a portion of the joint portion in the axial direction of the link pin.

7. The variable displacement supercharger according to claim 1, wherein the drive rod comprises a joint portion connected to the link pin, the drive lever comprises a thermal protection portion having an outer diameter equal to or greater than the outer diameter of the joint portion, and the thermal protection portion covers at least a portion of the joint portion in the axial direction of the link pin.

8. A variable displacement supercharger according to claim 1, further comprising a bearing housing connected to the turbine housing and forming the nozzle passage between itself and the turbine housing, wherein the turbine housing has a spigot portion into which the bearing housing fits and connects, and the link pin is positioned radially outward from the spigot portion with respect to the rotation axis of the turbine impeller.

9. The variable displacement supercharger according to claim 8, wherein the drive rod is positioned radially outward from the spigot portion.

10. The variable displacement supercharger according to claim 1, wherein the turbine housing has an end face facing the drive lever, and the link pin is positioned radially outward from the end face with respect to the rotation axis of the turbine blade.

11. The variable displacement supercharger according to claim 10, wherein the drive rod is positioned radially outward with respect to the end face.

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