Variable capacity mechanism and supercharger

Abstract

A variable capacity mechanism according to the present invention comprises: a plurality of nozzle vanes; nozzle rings which are disposed so as to be spaced apart from each other along the axes of the plurality of nozzle vanes such that the plurality of nozzle vanes are sandwiched therebetween; and a drive ring which is disposed on the nozzle ring support surface side of one nozzle ring opposite from the flow path formation surface of the nozzle ring that faces the plurality of nozzle vanes and which can rotate about the rotation axis of a turbine rotor while being in contact with the nozzle ring. At least one of a first portion of the nozzle ring which is in contact with the drive ring and a second portion of the drive ring which is in contact the nozzle ring is provided with a removal structure which removes a deposit adhering to the first portion of the nozzle ring and / or the second portion of the drive ring.

Description

Variable capacity mechanism and turbocharger

[0001] The present disclosure relates to variable displacement mechanisms.

[0002] In order to improve the efficiency of a turbocharger, the flow rate and speed of gas supplied to the turbine wheel may be adjusted. A mechanism for such adjustment is called a variable displacement mechanism or a variable nozzle unit. For example, Patent Document 1 discloses technology related to a variable displacement turbocharger equipped with a variable nozzle mechanism.

[0003] Patent No. 5409741

[0004] The variable displacement mechanism changes the area of ​​the flow passage through which gas flows and changes the direction of gas flow. The gas flow passage is formed by multiple nozzle vanes arranged along an imaginary circle. By moving the nozzle vanes, the variable displacement mechanism can change the area of ​​the flow passage formed between the nozzle vanes and change the direction of gas flow. In other words, the variable displacement mechanism includes movable parts whose positions change relative to each other.

[0005] The gas supplied to the turbocharger contains fine impurities such as soot. Because the variable displacement mechanism is exposed to the gas, soot accumulates on the variable displacement mechanism over time. The accumulated soot can interfere with the relative movement of the moving parts mentioned above. If the movement of the parts is obstructed, the variable displacement mechanism's ability to adjust the flow area and flow direction is impaired.

[0006] The present disclosure describes a variable displacement mechanism that can maintain the function of adjusting the flow path area and the flow direction, and a turbocharger equipped with the variable displacement mechanism.

[0007] A variable displacement mechanism according to one aspect of the present disclosure includes: a plurality of nozzle vanes that form a plurality of flow passages that guide gas from a scroll flow passage to a turbine wheel; a first plate member and a second plate member that are arranged spaced apart from each other along axes of the nozzle vanes so as to sandwich the plurality of nozzle vanes; and a drive ring that is arranged on a support surface of the second plate member that is opposite to a flow passage forming surface of the second plate member that faces the plurality of nozzle vanes and is rotatable about the rotation axis of the turbine wheel while contacting the second plate member. At least one of a first portion of the second plate member that contacts the drive ring and a second portion of the drive ring that contacts the second plate member is provided with a removal portion that removes deposits that adhere to the first portion of the second plate member and / or the second portion of the drive ring.

[0008] The variable displacement mechanism has a remover provided on at least one of a first portion of the second plate member that contacts the drive ring and a second portion of the drive ring that contacts the second plate member. The remover can remove deposits that adhere to the first portion of the second plate member and / or the second portion of the drive ring. As a result, the movement of the drive ring relative to the second plate member is not hindered by deposits, maintaining the function of adjusting the flow path area and flow direction.

[0009] In the above-described variable displacement mechanism, the first portion may be a support surface of the second plate member, and the second portion may be a contact surface of the drive ring that contacts the support surface of the second plate member. These configurations make it possible to remove deposits that have adhered to the support surface of the second plate member and the contact surface of the drive ring.

[0010] In the above-described variable displacement mechanism, the remover may be a textured surface provided on at least one of the support surface and the contact surface. With this configuration, the textured surface provided on at least one of the support surface and the contact surface can scrape off the deposits.

[0011] In the above-described variable displacement mechanism, the second plate member may include a drive ring support portion protruding from the support surface. The drive ring support portion may include a support outer circumferential surface located inside the drive ring and in contact with the ring inner circumferential surface of the drive ring. The first portion may be the support outer circumferential surface of the second plate member. The second portion may be the ring inner circumferential surface of the drive ring. These configurations make it possible to remove deposits adhering between the support outer circumferential surface of the second plate member and the ring inner circumferential surface of the drive ring.

[0012] In the above-described variable displacement mechanism, the first portion may be a portion of the support outer peripheral surface that faces the ring inner peripheral surface so as to be able to contact the ring inner peripheral surface. The second portion may be a portion of the ring inner peripheral surface that faces the support outer peripheral surface so as to be able to contact the support outer peripheral surface. These configurations make it possible to remove deposits that have adhered to the portion of the support outer peripheral surface that is able to contact the ring inner peripheral surface and the portion of the ring inner peripheral surface that is able to contact the support outer peripheral surface.

[0013] In the above-described variable displacement mechanism, the remover may be a textured surface provided on at least one of a portion facing the inner circumferential surface of the ring and a portion facing the outer circumferential surface of the support. With this configuration, the textured surface can scrape off deposits.

[0014] In the above-described variable displacement mechanism, the removal portion may be a support cutout provided on the inner peripheral surface of the drive ring and not in contact with the outer peripheral surface of the support. The removal portion may be a support cutout provided on the outer peripheral surface of the drive ring support portion and not in contact with the inner peripheral surface of the ring. These configurations allow deposits to be discharged from the support cutout.

[0015] In the above-described variable displacement mechanism, the inner peripheral surface of the drive ring may include a contact inner peripheral surface portion that can contact the outer peripheral surface of the support and a notched inner peripheral surface portion that cannot contact the outer peripheral surface of the support. The second portion may be a ridge portion connecting the contact inner peripheral surface portion and the notched inner peripheral surface portion. These configurations make it possible to scrape off deposits.

[0016] Another aspect of the present disclosure provides a turbocharger comprising: a turbine wheel; a housing including a flow path through which gas received from an inlet flows; and a variable capacity mechanism disposed in the housing and configured to receive the gas from the flow path and direct it to the turbine wheel. The variable capacity mechanism includes: a plurality of nozzle vanes forming a plurality of flow paths that direct gas from the scroll flow path to the turbine wheel; a first plate member and a second plate member disposed spaced apart from each other along the axes of the nozzle vanes and sandwiching the nozzle vanes; and a drive ring disposed on a support surface of the second plate member opposite a flow path forming surface of the second plate member facing the nozzle vanes, the drive ring being rotatable about the rotation axis of the turbine wheel while contacting the second plate member. At least one of a first portion of the second plate member that contacts the drive ring and a second portion of the drive ring that contacts the second plate member is provided with a removal portion that removes deposits adhering to the first portion of the second plate member and / or the second portion of the drive ring. This turbocharger comprises the variable capacity mechanism described above. As a result, the function of adjusting the flow passage area and the flow direction can be maintained, and the performance of the turbocharger can be maintained.

[0017] The variable displacement mechanism of the present disclosure and the turbocharger equipped with the variable displacement mechanism can maintain the function of adjusting the flow passage area and the flow direction.

[0018] FIG. 1 is a cross-sectional view of a turbocharger equipped with a variable capacity mechanism according to an embodiment. FIG. 2 is a perspective view of the variable capacity mechanism. FIG. 3 is a perspective view of a nozzle ring and a drive ring disassembled from a main surface of the drive ring. FIG. 4(a) is a plan view showing an enlarged first removed portion. FIG. 4(b) is a perspective view showing an enlarged first removed portion. FIG. 5 is a perspective view showing an enlarged second removed portion. FIG. 6 is a perspective view of a nozzle ring and a drive ring disassembled from a rear surface of the drive ring. FIG. 7 is a perspective view showing an enlarged third removed portion. FIGS. 8(a), 8(b), 8(c), 8(d), and 8(e) are views showing modified examples of the first removed portion. FIG. 9(a) is a view showing a cross-sectional shape of the second removed portion according to an embodiment. FIGS. 9(b) and 9(c) are views showing modified examples of the cross-sectional shape of the second removed portion. FIGS. 10(a), 10(b), and 10(c) are views showing modified examples of the second removed portion.

[0019] Hereinafter, a variable displacement mechanism and a turbocharger including the variable displacement mechanism, which are examples of the present disclosure, will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated explanations will be omitted.

[0020] Hereinafter, an embodiment of a variable displacement mechanism and a turbocharger including the variable displacement mechanism, which are examples of the present disclosure, will be described in detail with reference to the drawings. Fig. 1 is a cross-sectional view of a variable displacement turbocharger 1 including a rotation axis H. The turbocharger 1 is applied to an internal combustion engine of a ship or a vehicle, for example.

[0021] As shown in Fig. 1, the turbocharger 1 includes a turbine 2 and a compressor 3. The turbine 2 includes a turbine housing 4 and a turbine wheel 2T housed in the turbine housing 4. The turbine housing 4 has a scroll passage 16 extending in the circumferential direction around the turbine wheel 2T. The compressor 3 includes a compressor housing 12 and a compressor wheel 3T housed in the compressor housing 12. The compressor housing 12 has a scroll passage 17 extending in the circumferential direction around the compressor wheel 3T.

[0022] The turbine wheel 2T is provided at one end of the rotary shaft 14, and the compressor wheel 3T is provided at the other end of the rotary shaft 14. A bearing housing 13 is provided between the turbine housing 4 and the compressor housing 12. The rotary shaft 14 is rotatably supported by the bearing housing 13 via a bearing 15, and the rotary shaft 14, the turbine wheel 2T, and the compressor wheel 3T rotate around the rotation axis H as an integrated rotating body.

[0023] An exhaust gas inlet 10a and an exhaust gas outlet 10b are provided in the turbine housing 4. Exhaust gas discharged from the internal combustion engine flows into the turbine housing 4 through the exhaust gas inlet 10a, passes through the scroll passage 16, and flows into the turbine wheel 2T, causing the turbine wheel 2T to rotate. The exhaust gas then flows out of the turbine housing 4 through the exhaust gas outlet 10b.

[0024] The compressor housing 12 is provided with an intake port 11a and a discharge port 11b. When the turbine wheel 2T rotates as described above, the compressor wheel 3T rotates via the rotary shaft 14. The rotating compressor wheel 3T draws in external air through the intake port 11a. This air passes through the compressor wheel 3T and the scroll flow path 17, is compressed, and is discharged from the discharge port 11b. The compressed air discharged from the discharge port 11b is supplied to the internal combustion engine.

[0025] The turbine 2 of the turbocharger 1 will be further described. In the following description, the terms "axial direction," "radial direction," and "circumferential direction" simply refer to the direction of the rotational axis of the turbine wheel 2T (direction of the rotational axis H), the rotational radial direction, and the rotational circumferential direction, respectively. The terms "upstream," "downstream," and the like refer to the upstream and downstream of the exhaust gas in the turbine 2. In the direction of the rotational axis H, the turbine 2 side of the turbocharger 1 (left side in FIG. 1 ) may be simply referred to as the "turbine side," and the compressor 3 side (right side in FIG. 1 ) may be simply referred to as the "compressor side."

[0026] The turbine 2 of the turbocharger 1 is provided with a nozzle flow path 19 that connects the turbine wheel 2T to a scroll flow path 16 that is provided around the turbine wheel 2T. The nozzle flow path 19 is provided with a plurality of movable nozzle vanes 21. The plurality of nozzle vanes 21 are arranged at approximately equal intervals on a circumference centered on the rotation axis H. The nozzle vanes 21 rotate synchronously around an axis NX that is parallel to the rotation axis H. By rotating the plurality of nozzle vanes 21 as described above, the gaps between adjacent nozzle vanes 21 are expanded and contracted, thereby adjusting the opening degree of the nozzle flow path 19.

[0027] To drive the nozzle vanes 21 as described above, the turbine 2 is equipped with a variable capacity mechanism 20. The variable capacity mechanism 20 is fitted inside the turbine housing 4. The variable capacity mechanism 20 includes the plurality of nozzle vanes 21 described above and two nozzle rings 23 (second plate member) and 27 (first plate member) that axially sandwich the nozzle vanes 21. The two nozzle rings 23 and 27 are arranged in the axial direction, with the nozzle ring 23 being positioned closer to the compressor than the nozzle ring 27. The nozzle rings 23 and 27 each have a ring shape centered on the rotation axis H. The nozzle rings 23 and 27 are arranged to circumferentially surround the turbine impeller 2T. The area axially sandwiched between the two nozzle rings 23 and 27 forms the nozzle flow path 19 described above. The nozzle rings 23 and 27 are axially connected to each other via multiple connecting pins 29. The axial dimensional accuracy of the nozzle flow passage 19 is ensured by manufacturing the connecting pin 29 with high accuracy.

[0028] The variable displacement mechanism 20 has a drive mechanism 25 for driving the nozzle vanes 21. The drive mechanism 25 is housed in the space between the nozzle ring 23 and the bearing housing 13. The drive mechanism 25 transmits a drive force from an external actuator to the nozzle vanes 21.

[0029] The drive mechanism 25 of the variable displacement mechanism 20 will be described in further detail with reference to Figures 2 and 3. The nozzle ring 23 is provided with bearing holes 31 that penetrate therethrough in the axial direction. The rotation shafts 21a of the nozzle vanes 21 are rotatably inserted into the bearing holes 31. In the example shown in Figures 2 and 3, the nozzle vanes 21 are arranged at equal intervals on the circumference, but it is not essential that the nozzle vanes 21 be arranged at equal intervals.

[0030] The drive mechanism 25 includes a drive ring 33, a nozzle link plate 35, and a drive link plate 37. The drive ring 33 is ring-shaped and extends circumferentially about the rotation axis H. The drive ring 33 is disposed along the compressor-side surface of the nozzle ring 23. The drive ring 33 is rotatable about the rotation axis H relative to the nozzle ring 23. Engagement portions 33a that engage with the nozzle link plates 35 are provided on the drive ring 33 at predetermined intervals in the circumferential direction.

[0031] The nozzle link plates 35 are arranged in the same number as the nozzle vanes 21. The nozzle link plates 35 are attached to the ends of the rotation shafts 21a of the nozzle vanes 21. The nozzle link plates 35 extend radially outward from the ends of the rotation shafts 21a. More specifically, the rotation shafts 21a of the nozzle vanes 21 are inserted through the bearing holes 31. Each end of the rotation shaft 21a protrudes from the nozzle ring 23 toward the compressor. The inner peripheral end of each nozzle link plate 35 is attached to each end of the protruding rotation shaft 21a. The outer peripheral end of each nozzle link plate 35 meshes with the engaging portion 33a of the drive ring 33.

[0032] The drive ring 33 is provided with one input side engaging portion 33b. The input side engaging portion 33b is located between a pair of engaging portions 33a. The outer peripheral end of the drive link plate 37 is engaged with the input side engaging portion 33b. The inner peripheral end of the drive link plate 37 is connected to the drive shaft of an external actuator.

[0033] When an external actuator rotates the drive link plate 37 through a drive shaft about an axis parallel to the rotation axis H, the outer peripheral end of the drive link plate 37 presses the input side engaging portion 33b in the circumferential direction. This causes the drive ring 33 to rotate about the rotation axis H. As a result, each engaging portion 33a of the drive ring 33 presses the outer peripheral end of each nozzle link plate 35 in the circumferential direction. This causes each nozzle link plate 35 to rotate about the axis NX, and therefore each nozzle vane 21 fixed to each nozzle link plate 35 rotates about the axis NX.

[0034] The mechanism for removing deposits will be described in detail below with reference to Figure 3 and other figures. The drive ring 33 rotates relative to the nozzle ring 23. That is, the drive ring 33 moves while rubbing against the nozzle ring 23. If deposits such as soot adhere to the locations where this rubbing occurs, this may restrict the rotation of the drive ring 33 relative to the nozzle ring 23. The mechanism for removing deposits removes deposits that accumulate in the locations where this rubbing occurs.

[0035] The mechanism for removing deposits does not necessarily completely remove the accumulated deposits. "Removal" here means that the deposits are removed to the extent that the rotation of the drive ring 33 relative to the nozzle ring 23 is not restricted. In other words, even if deposits exist on the drive ring 33 and the nozzle ring 23, the deposits can be said to have been removed as long as the rotation of the drive ring 33 relative to the nozzle ring 23 is not restricted.

[0036] The locations where friction occurs due to rotation of the drive ring 33 relative to the nozzle ring 23 will be described. The nozzle ring 23 has a flow passage forming surface 23a and a nozzle ring support surface 23b. The flow passage forming surface 23a is the surface facing the nozzle ring 27, and multiple nozzle vanes 21 are arranged on it. The nozzle ring support surface 23b is the surface facing opposite to the flow passage forming surface 23a. The nozzle ring support surface 23b faces the bearing housing 13. The nozzle ring support surface 23b is an annular area provided on the outer periphery of the nozzle ring 23.

[0037] The nozzle ring 23 includes a drive ring support portion 231. The drive ring support portion 231 may be a part of the nozzle ring 23, or may be a separate component from the nozzle ring 23. The drive ring support portion 231 is a cylindrical protrusion that protrudes from the nozzle ring support surface 23b. The drive ring support portion 231 includes a main support surface 231p and an outer circumferential support surface 231s. Openings for multiple bearing holes 31 are formed in the drive ring support portion 231. In other words, multiple nozzle link plates 35 and a portion of one drive link plate 37 are arranged on the drive ring support portion 231.

[0038] A circular ring-shaped drive ring 33 is placed on the nozzle ring support surface 23b. When viewed in a plan view from the direction of the rotation axis H, the nozzle ring support surface 23b and the drive ring 33 may have substantially the same planar shape. For example, the outer diameter of the nozzle ring support surface 23b is the same as the outer diameter of the drive ring 33. A drive ring support portion 231 is located inside the drive ring 33. More specifically, a drive ring inner peripheral surface 33s faces a support outer peripheral surface 231s. The inner diameter of the drive ring inner peripheral surface 33s is substantially the same as the outer diameter of the support outer peripheral surface 231s. By loosely fitting the drive ring 33 into the drive ring support portion 231, movement of the drive ring 33 is restricted to rotation around the rotation axis H.

[0039] As a result, when the drive ring 33 rotates relative to the nozzle ring 23, friction occurs first between the nozzle ring support surface 23b and the drive ring back surface 33r, and second between the support outer peripheral surface 231s and the drive ring inner peripheral surface 33s. If deposits accumulate between the nozzle ring support surface 23b and the drive ring back surface 33r, rotation of the drive ring 33 relative to the nozzle ring 23 is restricted. Similarly, if deposits accumulate between the support outer peripheral surface 231s and the drive ring inner peripheral surface 33s, rotation of the drive ring 33 relative to the nozzle ring 23 is restricted. Therefore, the variable capacity mechanism 20 of this embodiment is provided with a first removal unit 5, a second removal unit 6, and a third removal unit 7. The first removal unit 5, the second removal unit 6, and the third removal unit 7 are collectively referred to as the removal structure 90.

[0040] <First removal portion> FIGS. 4( a) and 4(b) are enlarged views of the first removal portion 5. The first removal portion 5 is formed on the drive ring 33. In the example of this embodiment, three first removal portions 5 are provided on the drive ring 33. More specifically, the first removal portion 5 is provided on the drive ring inner circumferential surface 33s. The number of first removal portions 5 is not limited to three; it is sufficient that at least one is provided on the drive ring 33. The number of first removal portions 5 may be three or more. The first removal portion 5 can scrape off deposits adhering to the support outer circumferential surface 231s. Therefore, the first removal portion 5 may be provided at a location on the support outer circumferential surface 231s where deposits are likely to accumulate.

[0041] The first removal portion 5 is a notch provided in the drive ring inner peripheral surface 33s. Here, the drive ring inner peripheral surface 33s includes a portion that can contact the support outer peripheral surface 231s (drive ring inner peripheral contact surface 33s1) and a portion that cannot contact the support outer peripheral surface 231s (drive ring removal portion inner peripheral surface 33s2). At the portion that can contact the support outer peripheral surface 231s, there is a very small gap between the support outer peripheral surface 231s and the support outer peripheral surface 231s, but the inner diameter of the gap is approximately the same as the outer diameter of the support outer peripheral surface 231s. Therefore, when the drive ring 33 rotates, the portion that can contact the support outer peripheral surface 231s may rub against the support outer peripheral surface 231s. In contrast, the notch portion, which is a portion that cannot contact the support outer peripheral surface 231s, does not contact the support outer peripheral surface 231s even when the drive ring 33 rotates. In other words, the peripheral surface of the notch portion is significantly spaced from the support outer peripheral surface 231s.

[0042] In the example shown in Figure 4(a), the first removal portion 5, which is a cutout portion, has a semicircular planar shape. A portion of the nozzle ring support surface 23b of the nozzle ring 23 is exposed from the first removal portion 5. A removal edge 51 is provided at a ridge (corner) connecting the drive ring inner peripheral contact surface 33s1 (contact inner peripheral surface portion) and the drive ring removal portion inner peripheral surface 33s2 (cutout inner peripheral surface portion). The removal edge 51 is the first removal portion 5 in the narrow sense.

[0043] The removal edge 51 is a ridgeline connecting the drive ring inner peripheral contact surface 33s1 and the drive ring removal portion inner peripheral surface 33s2. Therefore, the radial position of the removal edge 51 is the same as the inner diameter of the drive ring inner peripheral contact surface 33s1. As a result, if deposits adhere to the support outer peripheral surface 231s to a height exceeding the drive ring inner peripheral contact surface 33s1, the deposits are scraped off by the removal edge 51. The height of the deposits scraped off by the removal edge 51 may vary depending on the location on the support outer peripheral surface 231s.

[0044] The shape of the removal edge 51 can also be defined as the angle between the drive ring inner peripheral contact surface 33s1 and the drive ring removal portion inner peripheral surface 33s2. More specifically, the angle between the drive ring inner peripheral contact surface 33s1 and the drive ring removal portion inner peripheral surface 33s2 is a so-called acute angle. When the removal edge 51 having such an angle is pressed against the deposit by the rotation of the drive ring 33, the direction of the force applied from the removal edge 51 to the deposit is directed away from the support outer peripheral surface 231s. Therefore, the deposit can be effectively scraped off.

[0045] <Second removal unit> The first removal unit 5 can remove deposits accumulated on the support outer peripheral surface 231s within the range of movement of the removal edge 51 when the drive ring 33 rotates. Therefore, deposits accumulated on the support outer peripheral surface 231s outside the range of movement of the removal edge 51 cannot be removed by the first removal unit 5. Therefore, the second removal unit 6 is provided in the range where the first removal unit 5 cannot remove deposits.

[0046] Like the first removal portions 5, the second removal portions 6 are also provided on the drive ring inner peripheral surface 33s. More specifically, the second removal portions 6 are provided on the drive ring inner peripheral contact surface 33s1. In other words, the second removal portions 6 can be said to be provided between two adjacent first removal portions 5. The second removal portions 6 may be provided on the entire drive ring inner peripheral contact surface 33s1. The second removal portions 6 may be provided on a portion of the drive ring inner peripheral contact surface 33s1. The example in FIG. 3 illustrates the second removal portions 6 provided on a portion of the drive ring inner peripheral contact surface 33s1.

[0047] As shown in FIG. 5 , the second removal portion 6 is a fine uneven structure provided on the drive ring inner peripheral contact surface 33s1. The second removal portion 6 may be defined as a protrusion that protrudes from the drive ring inner peripheral contact surface 33s1. Alternatively, the second removal portion 6 may be defined as a groove that is carved from the drive ring inner peripheral contact surface 33s1. Such an uneven structure can scrape off deposits that have accumulated on the support outer peripheral surface 231s. An example of an uneven structure is one having a triangular cross-sectional shape. The ridge lines that form the vertices of the triangle extend from the drive ring main surface 33p toward the drive ring back surface 33r. In other words, the ridge lines that form the vertices of the triangle extend in the direction of the rotation axis H.

[0048] <Third removal unit> The first removal unit 5 and second removal unit 6 described above are intended to remove deposits accumulated on the support outer peripheral surface 231s. The third removal unit 7 is intended to remove deposits accumulated on the nozzle ring support surface 23b. The third removal unit 7 is provided on the drive ring back surface 33r.

[0049] Fig. 6 is an exploded perspective view of the nozzle ring 23 and the drive ring 33, viewed from the rear side. As with Fig. 3, Fig. 6 does not show other components that make up the variable capacity mechanism 20. Fig. 7 is an enlarged perspective view of a portion of Fig. 6.

[0050] The third removal portion 7 is a fine uneven structure provided on the drive ring back surface 33r, like the second removal portion 6. The third removal portion 7 may be defined as a protrusion that protrudes from the drive ring back surface 33r. The third removal portion 7 may also be understood as a groove that is carved from the drive ring back surface 33r. Such an uneven structure can scrape off deposits that have accumulated on the nozzle ring support surface 23b. Like the second removal portion 6, an example of an uneven structure has a triangular cross-sectional shape. The ridges that form the vertices of the triangle extend radially. In other words, each ridge extends toward the rotation axis H.

[0051] <Discharge Notch> It is desirable to discharge the scraped-off deposits to the outside. Therefore, a discharge notch 8 may be provided to discharge the scraped-off deposits. The discharge notch 8 may be provided only on the drive ring inner peripheral surface 33s of the drive ring 33. The discharge notch 8 may be provided only on the support outer peripheral surface 231s of the drive ring support portion 231. The discharge notch 8 may be provided on both the drive ring inner peripheral surface 33s and the support outer peripheral surface 231s. The example in Figure 3 shows a configuration in which the discharge notch 8 is provided only on the drive ring inner peripheral surface 33s of the drive ring 33.

[0052] The discharge notch 8 is an open hole that extends from the drive ring main surface 33p to the drive ring back surface 33r. Like the first removal portion 5, the discharge notch 8 does not come into contact with the support outer peripheral surface 231s. Therefore, the first removal portion 5 also achieves the same effect as the discharge notch 8. In the example shown in FIG. 3 , the drive ring 33 is provided with two discharge notches 8. The number of discharge notches 8 is not limited to two. When a discharge notch 8 is provided, the number of discharge notches 8 needs to be at least one. The discharge notch 8 may be omitted.

[0053] <Effects> The variable capacity mechanism 20 includes a plurality of nozzle vanes 21 that form a plurality of flow paths that guide gas from the scroll flow path to the turbine wheel 2T, nozzle rings 23, 27 that are arranged spaced apart from each other along the axis NX of the nozzle vanes 21 so as to sandwich the plurality of nozzle vanes 21, and a drive ring 33 that is arranged on a nozzle ring support surface 23b of the nozzle ring 23 that is opposite to a flow path forming surface 23a of the nozzle ring 23 that faces the plurality of nozzle vanes 21, and that is rotatable about the rotation axis H of the turbine wheel 2T while contacting the nozzle ring 23. At least one of a first portion of the nozzle ring 23 that contacts the drive ring 33 and a second portion of the drive ring 33 that contacts the nozzle ring 23 is provided with a removal structure 90 that removes deposits that adhere to the first portion of the nozzle ring 23 and / or the second portion of the drive ring 33.

[0054] This variable capacity mechanism 20 has a removal structure 90 provided on at least one of a first portion of the nozzle ring 23 that contacts the drive ring 33 and a second portion of the drive ring 33 that contacts the nozzle ring 23. The removal structure 90 makes it possible to remove deposits that adhere to the first portion of the nozzle ring 23 and / or the second portion of the drive ring 33. As a result, the movement of the drive ring 33 relative to the nozzle ring 23 is not hindered by deposits, and the function of adjusting the flow path area and flow direction can be maintained.

[0055] The first portion is the support surface of the nozzle ring 23. The second portion is the contact surface of the drive ring 33 that contacts the support surface of the nozzle ring 23. With these configurations, deposits that have adhered to the support surface of the nozzle ring 23 and the contact surface of the drive ring 33 can be removed.

[0056] The third removal portion 7 is a textured surface portion provided on at least one of the nozzle ring support surface 23 b and the drive ring back surface 33 r. With this configuration, the textured surface portion provided on at least one of the nozzle ring support surface 23 b and the drive ring back surface 33 r can scrape off deposits.

[0057] The nozzle ring 23 includes a drive ring support portion 231 that protrudes from the nozzle ring support surface 23b. The drive ring support portion 231 includes a support outer peripheral surface 231s that is located inside the drive ring 33 and that contacts the drive ring inner peripheral surface 33s of the drive ring 33. The first portion is the support outer peripheral surface 231s of the nozzle ring 23. The second portion is the ring inner peripheral surface of the drive ring 33. With this configuration, it is possible to remove deposits that have adhered between the support outer peripheral surface 231s of the nozzle ring 23 and the drive ring inner peripheral surface 33s of the drive ring 33.

[0058] The first portion is a portion of the support outer peripheral surface 231s that faces the drive ring inner peripheral surface 33s and is capable of contacting the drive ring inner peripheral surface 33s. The second portion is a portion of the drive ring inner peripheral surface 33s that faces the support outer peripheral surface 231s and is capable of contacting the support outer peripheral surface 231s. These configurations make it possible to remove deposits that have adhered to the portion of the support outer peripheral surface 231s that is capable of contacting the drive ring inner peripheral surface 33s and the portion of the drive ring inner peripheral surface 33s that is capable of contacting the support outer peripheral surface 231s.

[0059] The second removal portion 6 is a textured surface portion provided on at least one of a portion facing the drive ring inner peripheral surface 33 s and a portion facing the support outer peripheral surface 231 s. With this configuration, the textured surface portion can scrape off deposits.

[0060] The discharge notch 8 is a cutout portion that is provided on the drive ring inner peripheral surface 33s of the drive ring 33 and does not come into contact with the support outer peripheral surface 231s. With this configuration, it is possible to discharge deposits from the discharge notch 8.

[0061] The drive ring inner peripheral surface 33s of the drive ring 33 includes a drive ring inner peripheral contact surface 33s1 that can contact the support outer peripheral surface 231s, and a drive ring removal portion inner peripheral surface 33s2 that cannot contact the support outer peripheral surface 231s. The removal edge 51 of the first removal portion 5 is a ridge line that connects the drive ring inner peripheral contact surface 33s1 and the drive ring removal portion inner peripheral surface 33s2. This configuration makes it possible to scrape off any adhering material.

[0062] Although the variable displacement mechanism and the turbocharger including the variable displacement mechanism have been described above as examples of the present disclosure, the variable displacement mechanism and the turbocharger including the variable displacement mechanism as examples of the present disclosure are not limited to the above-described embodiment, and modifications are permitted within the scope of the gist of each claim. The configurations of the respective embodiments may be combined as appropriate.

[0063] In the above example, the first removal portion 5 is an edge extending along the thickness direction of the drive ring 33. For example, the first removal portion 5 may be a linear removal edge 51A that is inclined with respect to the thickness direction of the drive ring 33 (see FIG. 8( a)). The edge that forms the first removal portion 5 is not limited to being linear, and may be an arc-shaped removal edge 51B, 51C (see FIGS. 8( b) and 8( c)).

[0064] 8( d ), the first removal unit 5D may include a cutting edge 52 in addition to the removal edge 51D. With this first removal unit 5D, the deposits can be removed by pushing them aside in the thickness direction of the drive ring 33.

[0065] In the above example, the first removal portion 5 is formed from three arcs in plan view. For example, as illustrated in Fig. 8(e), the first removal portion 5E may be formed from a single arc.

[0066] In the above example, the cross-sectional shape of the second removal portion 6 and the third removal portion 7 is shown as a triangle (see FIG. 9( a)). Shapes such as those shown in FIGS. 9( b) and 9( c) can also be adopted as the cross-sectional shapes of the second removal portion 6 and the third removal portion 7. FIG. 9( a) shows the cross-sectional shape exemplified in the embodiment. As shown in FIG. 9( b), the cross-sectional shape is generally triangular, but the apex 6t may be rounded. As shown in FIG. 9( c), the cross-sectional shape is generally triangular, but the apex 6t may be flattened. Shapes such as those shown in FIGS. 9( b) and 9( c) can reduce damage to the support outer peripheral surface 231 s and the nozzle ring support surface 23 b even when the second removal portion 6 and the third removal portion 7 directly rub against the support outer peripheral surface 231 s and the nozzle ring support surface 23 b.

[0067] In the above example, the second removal portion 6 is oriented along the thickness direction of the drive ring 33. A second removal portion 6 with such a structure can also be described as having a flat grain pattern. For example, as shown in FIGS. 10( a) and 10(b), the second removal portions 6A and 6B may be oriented at an angle relative to the thickness direction of the drive ring 33. By oriented at an angle in this manner, the force exerted on the deposits by rotation of the drive ring 33 can be directed toward the drive ring rear surface 33r or the drive ring main surface 33p. As shown in FIG. 10(c), the second removal portion 6C may have a so-called twill pattern. Such a twill pattern can be formed by so-called knurling. The variations shown in FIGS. 10(a), 10(b), and 10(c) may be applied not only to the second removal portion 6 but also to the third removal portion 7.

[0068] In the above example, the deposits are described as accumulating on the support outer peripheral surface 231s and the nozzle ring support surface 23b. However, deposits may also accumulate on the drive ring inner peripheral surface 33s and the drive ring back surface 33r. Therefore, the second removal unit 6 may be provided on the drive ring inner peripheral surface 33s. The third removal unit 7 may be provided on the drive ring back surface 33r.

[0069] The first removal unit 5, the second removal unit 6, and the third removal unit 7 may be provided at locations facing areas where deposits are likely to accumulate. For example, with respect to the support outer peripheral surface 231s and the drive ring inner peripheral surface 33s, the second removal unit 6 may be provided on the support outer peripheral surface 231s at one location and on the drive ring inner peripheral surface 33s at another location. The second removal unit 6 may be provided on both the support outer peripheral surface 231s and the drive ring inner peripheral surface 33s. Similarly, with respect to the nozzle ring support surface 23b and the drive ring back surface 33r, the third removal unit 7 may be provided on the nozzle ring support surface 23b at one location and on the drive ring back surface 33r at another location.

[0070] The variable capacity mechanism 20 does not need to include all of the first removal unit 5, the second removal unit 6, and the third removal unit 7, but may include at least one of them. The variable capacity mechanism 20 may include only the first removal unit 5. The variable capacity mechanism 20 may include only the second removal unit 6. The variable capacity mechanism 20 may include only the third removal unit 7. The variable capacity mechanism 20 may include the first removal unit 5 and the second removal unit 6. The variable capacity mechanism 20 may include the first removal unit 5 and the third removal unit 7. The variable capacity mechanism 20 may include the second removal unit 6 and the third removal unit 7.

[0071] DESCRIPTION OF SYMBOLS 1 Turbocharger 2 Turbine 2T Turbine impeller 3 Compressor 3T Compressor impeller 4 Turbine housing (housing) 5 First removed portion 6, 6A, 6B, 6C Second removed portion 6t Top portion 7 Third removed portion 8 Discharge notch 12 Compressor housing 13 Bearing housing 14 Rotating shaft 15 Bearing 16 Scroll passage 17 Scroll passage 19 Nozzle passage 20 Variable capacity mechanism 21 Nozzle vane 21a Rotating shaft 23 Nozzle ring (second plate member) 23a Passage forming surface 23b Nozzle ring support surface 25 Drive mechanism portion 27 Nozzle ring (first plate member) 29 Connecting pin 31 Bearing hole 33 Drive ring 33a Engagement portion 33b Input side engagement portion 33p Drive ring main surface 33r Drive ring back surface 33s: Drive ring inner peripheral surface 33s1: Drive ring inner peripheral contact surface (contact inner peripheral surface portion) 33s2: Drive ring removal portion inner peripheral surface (notched inner peripheral surface portion) 35: Nozzle link plate 37: Drive link plate 51, 51A, 51B, 51C: Removal edge 52: Cutting edge 90: Removal structure 231: Drive ring support portion 231s: Support outer peripheral surface H: Rotation axis NX: Axis

Claims

1. A variable displacement mechanism comprising: a plurality of nozzle vanes that form a plurality of flow paths that guide gas from a scroll flow path to a turbine wheel; a first plate member and a second plate member that are arranged spaced apart from each other along the axes of the plurality of nozzle vanes so as to sandwich the plurality of nozzle vanes; and a drive ring that is arranged on the support surface of the second plate member that is opposite to the flow path forming surface of the second plate member that faces the plurality of nozzle vanes, and that is rotatable around the rotation axis of the turbine wheel while contacting the second plate member, wherein at least one of a first portion of the second plate member that contacts the drive ring and a second portion of the drive ring that contacts the second plate member is provided with a removal section that removes deposits that adhere to the first portion of the second plate member and / or the second portion of the drive ring.

2. The variable displacement mechanism according to claim 1, wherein the first portion is the support surface of the second plate member, and the second portion is the contact surface of the drive ring that contacts the support surface of the second plate member.

3. The variable displacement mechanism according to claim 2, wherein the removed portion is a textured surface portion provided on at least one of the support surface and the contact surface.

4. A variable displacement mechanism as described in claim 1, wherein the second plate member includes a drive ring support portion that protrudes from the support surface, the drive ring support portion includes a support outer surface that is located inside the drive ring and contacts the ring inner surface of the drive ring, the first portion is the support outer surface of the second plate member, and the second portion is the ring inner surface of the drive ring.

5. A variable capacity mechanism as described in claim 4, wherein the first portion is a portion of the support outer surface facing the inner peripheral surface of the ring so as to be able to contact the inner peripheral surface of the ring, and the second portion is a portion of the ring inner peripheral surface facing the outer peripheral surface of the support so as to be able to contact the outer peripheral surface of the support.

6. A variable displacement mechanism according to claim 5, wherein the removed portion is a textured surface portion provided on at least one of the portion facing the inner peripheral surface of the ring and the portion facing the outer peripheral surface of the support.

7. The variable displacement mechanism according to claim 5, wherein the removed portion is a support notch provided on the inner peripheral surface of the drive ring and not in contact with the outer peripheral surface of the support.

8. The variable displacement mechanism according to claim 5, wherein the removed portion is a support notch provided on the outer support surface of the drive ring support portion and does not contact the inner ring surface.

9. A variable displacement mechanism as described in claim 5, wherein the inner peripheral surface of the drive ring includes a contact inner peripheral surface portion that can come into contact with the outer peripheral surface of the support and a notched inner peripheral surface portion that cannot come into contact with the outer peripheral surface of the support, and the second portion is a ridge portion that connects the contact inner peripheral surface portion and the notched inner peripheral surface portion.

10. A turbocharger comprising: a turbine wheel; a housing including a flow path through which gas received from an inlet flows; and a variable capacity mechanism that is arranged in the housing and receives the gas from the flow path and directs it to the turbine wheel, wherein the variable capacity mechanism comprises: a plurality of nozzle vanes that form a plurality of flow paths that direct gas from a scroll flow path to the turbine wheel; a first plate member and a second plate member that are arranged spaced apart from each other along the axes of the plurality of nozzle vanes so as to sandwich the plurality of nozzle vanes; and a drive ring that is arranged on the support surface of the second plate member that is opposite to the flow path forming surface of the second plate member that faces the plurality of nozzle vanes, and is rotatable about the rotation axis of the turbine wheel while contacting the second plate member, wherein at least one of a first portion of the second plate member that contacts the drive ring and a second portion of the drive ring that contacts the second plate member is provided with a removal section that removes deposits that adhere to the first portion of the second plate member and / or the second portion of the drive ring.

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