JP5141335B2 - Variable nozzle unit and variable displacement turbocharger - Google Patents

Description

  The present invention relates to a variable nozzle unit that varies the flow rate of exhaust gas supplied to a turbine impeller side in a variable displacement turbocharger, and a variable displacement turbocharger.

  In recent years, variable capacity turbochargers equipped with a variable nozzle unit that changes the flow rate of exhaust gas supplied to the turbine impeller side have been developed so that high efficiency can be achieved even in the low engine speed range (patent) Reference 1). The configuration of the variable nozzle unit in the variable capacity turbocharger according to the prior art will be briefly described as follows.

  A nozzle ring is provided as a first base ring member in the turbine housing. Further, a shroud ring as a second base ring member is provided at a position facing the nozzle ring so as to surround the turbine impeller, and the nozzle ring is located concentrically with the shroud ring.

  A plurality of nozzle vanes are provided at equal intervals along the circumferential direction between the shroud ring and the seal ring, and each nozzle vane is parallel to the axis of the shroud ring (in other words, the axis of the seal ring). Each of them can be rotated around a central axis. Further, a first vane shaft is integrally formed on one side surface of each nozzle vane, and each first vane shaft is rotatably supported by the nozzle ring. Further, a second vane shaft is integrally formed on the other side surface of each nozzle vane concentrically with the first vane shaft, and each second vane shaft is rotatably supported by the shroud ring. . The plurality of nozzle vanes are configured to rotate synchronously while operating a synchronization mechanism by driving an appropriate actuator.

Accordingly, when the engine speed is in the high speed range, the synchronizing mechanism is operated by driving an appropriate actuator, and the plurality of nozzle vanes are rotated synchronously in the opening direction to be supplied to the turbine impeller side. Increase the exhaust gas flow rate to lower the exhaust gas pressure. On the other hand, when the engine speed is in a low speed range, the turbine impeller side is operated by rotating the plurality of nozzle vanes in the direction of closing (closing direction) while operating the synchronization mechanism by driving an appropriate actuator. The flow rate of exhaust gas supplied to is reduced, and the pressure of exhaust gas is increased. Therefore, even in a low speed region of the engine speed, it is possible to sufficiently ensure the work amount of the turbine impeller and exhibit high efficiency.
JP 2007-231934 A

  By the way, normally, in order to improve the performance of the variable capacity turbocharger, the side nozzle gap of the variable nozzle unit (the distance between the wall surface of the base ring member and the side surface of the nozzle vane) is set small. Therefore, if thermal deformation of the variable nozzle unit or tilting of the nozzle shaft occurs during operation of the variable displacement turbocharger, the operating agility of the nozzle vane increases, in other words, the life of the variable nozzle unit, in other words, the variable displacement turbocharger. It becomes difficult to extend the life of the charger sufficiently. On the other hand, by forming a low friction coat on the wall surface of the nozzle ring and the wall surface of the shroud nozzle by thermal spraying etc., countermeasures have been taken to reduce the operating agility of the nozzle vane, but the manufacturing process of the variable nozzle unit has increased, making it variable. The manufacturing cost of the nozzle unit, in other words, the manufacturing cost of the variable capacity turbocharger increases.

  That is, there is a problem that it is difficult to sufficiently extend the life of the variable capacity turbocharger while suppressing an increase in the manufacturing cost of the variable capacity turbocharger.

  Therefore, an object of the present invention is to provide a variable nozzle unit and a variable displacement turbocharger having a novel configuration that can solve the above-described problems.

A first feature of the present invention is a variable nozzle unit that varies the flow rate of exhaust gas supplied to a turbine impeller side in a variable displacement turbocharger, and a pair of base ring members provided facing each other; Provided at equal intervals along the circumferential direction between the base ring members, each being rotatable about an axis parallel to the axis of the base ring member, and integrally formed on at least one side surface and the base A plurality of nozzle vanes each provided with a vane shaft rotatably supported by a ring member, and on both sides of the vane shaft on one side surface of each nozzle vane and only on the axial center side portion of the vane shaft , is formed integrally a first contact allowable protrusion to permit contact with the wall surface of one of the base ring member, respectively, convex surface of the first contact permissible protrusions the Roh Has become parallel to one side of the vanes, only the axial portion of said vane axis A both sides of the vane axis in the other side of each nozzle vane, the contact with the wall surface of the other of the base ring member The gist is that the second allowable contact protrusions to be allowed are integrally formed, and the convex surface of each second allowable contact protrusion is parallel to the other side surface of the nozzle vane .

  In the claims and specification of the present application, “provided” means not only directly provided but also indirectly provided via an intermediate member.

  According to the first feature, when the engine speed is in a high speed range, the flow rate of the exhaust gas supplied to the turbine impeller side is increased by rotating the plurality of nozzle vanes synchronously in the opening direction. Then, the pressure of the exhaust gas is lowered. On the other hand, when the engine speed is in the low speed range, the flow rate of the exhaust gas supplied to the turbine impeller side is reduced by rotating the nozzle vanes in synchronization with the direction of closing (closing direction). Increase the exhaust gas pressure. Therefore, even in a low speed region of the engine speed, it is possible to sufficiently secure the work amount of the turbine impeller and exhibit high efficiency (general operation of the variable nozzle unit).

  If thermal deformation of the variable nozzle unit or tilting of the vane shaft occurs during the operation of the variable displacement turbocharger, the first contact-permissible convex portion is one before the two tips of one side surface of the nozzle vane. The second contact-permitting convex portion comes into contact with the other base ring member prior to both ends of the other side surface of the nozzle vane. Thereby, when the first contact allowable convex portion and the second contact allowable convex portion are in contact with the wall surface of the nozzle base member by an amount closer to the axial center side of the vane than the tip of the side surface of the nozzle vane. The rotation load (rotation resistance) of the nozzle vane can be reduced. That is, it is possible to sufficiently reduce the operation agitation of the nozzle vane during operation of the variable displacement turbocharger without forming a low wear coat on the wall surface of the base ring member by spraying or the like (the variable nozzle unit). Specific action).

  The second feature is that the variable capacity turbocharger that supercharges the air supplied to the engine using the energy of the exhaust gas from the engine comprises the variable nozzle unit comprising the first feature. The gist.

  According to the 2nd characteristic, there exists an effect | action similar to the effect | action by a 1st characteristic.

  According to the present invention, the variable operation of the nozzle vane during operation of the variable displacement turbocharger can be sufficiently reduced without forming a low wear coat on the wall surface of the base ring member by spraying or the like. The life of the variable displacement turbocharger can be sufficiently extended while suppressing an increase in the manufacturing cost of the displacement turbocharger.

  An embodiment of the present invention will be described with reference to FIGS. Here, FIG. 1 is an enlarged view of the arrow I in FIG. 3, FIG. 2 is a diagram for explaining the operation of the embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along line III-III in FIG. 4 is a front view of the variable nozzle unit according to the embodiment of the present invention, FIG. 5 is a rear view of the variable nozzle unit according to the embodiment of the present invention, and FIG. 6 is an enlarged view of the arrow VI in FIG. FIG. 7 is a cross-sectional view of the variable capacity turbocharger according to the embodiment of the present invention. In the drawings, “F” indicates the forward direction, and “R” indicates the backward direction.

  As shown in FIGS. 6 and 7, the variable capacity turbocharger 1 according to the embodiment of the present invention supercharges the air supplied to the engine using the energy of the exhaust gas from the engine (not shown). To do. The variable capacity turbocharger 1 includes a bearing housing 3. A turbine housing 5 is provided at the front peripheral edge of the bearing housing 3. A compressor housing 7 is provided.

  A plurality of bearings 9 are provided in the bearing housing 3, and a turbine shaft 11 extending in the front-rear direction is rotatably provided on the plurality of bearings 9. A turbine impeller 13 is provided in the turbine housing 5, and the turbine impeller 13 is integrally connected to the front end portion of the turbine shaft 11. Further, a compressor impeller 15 is provided in the compressor housing 7, and the compressor impeller 15 is integrally connected to the front end portion of the turbine shaft 11.

  A gas intake (not shown) for taking in exhaust gas is formed at an appropriate position of the turbine housing 5, and this gas intake can be connected to a cylinder (not shown) of the engine. Further, a turbine scroll passage 17 is formed inside the turbine housing 5 so as to surround the turbine impeller 13, and the turbine scroll passage 17 communicates with a gas intake port. Further, a gas discharge port 19 for discharging exhaust gas is formed on the front side of the turbine housing 5 (in other words, on the outlet side of the turbine impeller 13). This gas discharge port 19 is connected to the turbine scroll flow path 17. It communicates and can be connected to an exhaust gas purification device (not shown).

  An air intake 21 for taking in air is formed on the rear side of the compressor housing 7 (in other words, on the inlet side of the compressor impeller 15). This air intake 21 can be connected to an air cleaner (not shown). It is. The bearing housing 3 and the compressor housing 7 are each formed with an annular diffuser passage 23 that pressurizes compressed air so as to surround the compressor impeller 15. The diffuser passage 23 is connected to the air intake 21. Communicated. Further, a compressor scroll passage 25 is formed inside the compressor housing 7 so as to surround the compressor impeller 15, and the compressor scroll passage 25 communicates with the diffuser passage 23. An air discharge port (not shown) for discharging compressed air is formed at an appropriate position of the compressor housing 7, and this air discharge port communicates with the compressor scroll flow path 25, and Can be connected to other cylinders.

  Therefore, when the exhaust gas taken in from the gas intake is supplied to the turbine impeller 13 side via the turbine scroll passage 17, the turbine impeller 13 can be rotationally driven by the energy of the exhaust gas, and the compressor impeller 15 can be driven. It can be driven to rotate in conjunction with each other via the turbine shaft 11. Thereby, the air taken in from the air intake 21 can be compressed by the compressor impeller 15 and discharged from the air discharge port via the diffuser flow path 23 and the compressor scroll flow path 25 and supplied to the engine cylinder. The air can be supercharged.

  A variable nozzle unit 27 that varies the flow rate of exhaust gas supplied to the turbine impeller 13 side is provided in the turbine housing 5, and the specific configuration of the variable nozzle unit 27 is as follows.

  As shown in FIGS. 1, 3, and 4, a nozzle ring 29 is provided as a first base ring member concentrically with the turbine impeller 13 in the turbine housing 5. A shroud ring 31 as a second base ring member is provided integrally and concentrically with the nozzle ring 29 so as to surround the turbine impeller 13 via a plurality of connecting pins 33.

  A mounting ring 35 is integrally provided on the rear side of the nozzle ring 29 via a plurality of connecting pins 33, and an outer peripheral edge portion of the mounting ring 35 is sandwiched between the turbine housing 5 and the bearing housing 3. It has become so. In other words, the nozzle ring 29 is provided in the turbine housing 5 via the mounting ring 35.

  A plurality of nozzle vanes 37 are provided at equal intervals along the circumferential direction between the nozzle ring 29 and the shroud ring 31, and each nozzle vane 37 is provided at the axis of the nozzle ring 29 (the axis of the shroud ring 31). Each of them can be rotated around a parallel axis. In addition, a first vane shaft 39 is integrally formed on one side surface (rear side surface) of each nozzle vane 37, and each first vane shaft 39 is rotatably supported by the nozzle ring 29. Yes. Further, a second vane shaft 41 is integrally formed on the other side surface (front side surface) of each nozzle vane 37 concentrically with the first vane shaft 39, and each second vane shaft 41 is formed by a shroud ring. 31 is supported so as to be rotatable. The nozzle vane 37 is a both-end support type, but the nozzle vane 37 may be a one-end support type by omitting the second vane shaft 41, for example.

  A pair of first contact-permitting convex portions 43 that allow contact with the wall surface of the nozzle ring 29 are integrally formed on the axial center side portion of the first vane shaft 39 on one side surface of each nozzle vane 37, respectively. The pair of first contact allowable protrusions 43 are located on both sides of the first vane shaft 39. Further, the convex surface (rear side surface) of each first contact allowable convex portion 43 is parallel to one side surface of the nozzle vane 37.

  A pair of second contact-permitting convex portions 45 that allow contact with the wall surface of the shroud ring 31 are integrally formed on the axial side portion of the second vane shaft 41 on the other side surface of each nozzle vane 37, respectively. The pair of second contact allowable protrusions 45 are located on both sides of the second vane shaft 41. Further, the convex surface (front side surface) of each second contact allowable convex portion 45 is parallel to the other side surface of the nozzle vane 37.

  As shown in FIGS. 3, 4, and 5, a synchronization mechanism 47 that synchronizes the rotational operations of the plurality of nozzle vanes 37 is provided on the rear side of the nozzle ring 29.

  Specifically, a guide ring 49 is provided on the rear side of the nozzle ring 29 via a plurality of connecting pins 33, and a movable ring 51 is rotatably provided on the guide ring 49. . The movable ring 51 is located concentrically with the nozzle ring 29, and the same number of synchronizing engaging recesses 53 as the nozzle vanes 37 are formed at equal intervals along the circumferential direction inside the movable ring 51. ing. The base end portions of the synchronization transmission links 55 are integrally connected to the vane shafts 39, and the distal ends of the synchronization transmission links 55 are respectively engaged with the corresponding synchronization engagement recesses 53. Yes.

  In addition to the plurality of synchronization engagement recesses 53, a drive engagement recess 57 is formed inside the movable ring 51. Further, a drive shaft 59 that is rotatable around an axis parallel to the axis of the nozzle ring 29 is provided at the lower front side of the bearing housing 3, and one end (rear end) of the drive shaft 59 is provided. The base end portion of the drive lever 61 is integrally connected, and an actuator (not shown) such as a cylinder is interlocked and connected to the drive lever 61. The other end portion (front end portion) of the drive shaft 59 is integrally connected to the base end portion of the drive transmission link 63, and the distal end portion of the drive transmission link 63 is engaged with the drive engagement recess 57. Yes.

  Then, the effect | action and effect of embodiment of this invention are demonstrated.

  When the engine speed is in a high speed range, the drive transmission link 63 is rotated in one direction via the drive lever 61 by driving the actuator, thereby operating the synchronization mechanism 47 and moving the plurality of nozzle vanes 37. Rotate synchronously in the opening direction. Thereby, the flow volume of the exhaust gas supplied to the turbine impeller 13 side can be increased, and the pressure of the exhaust gas can be lowered.

  On the other hand, when the engine speed is in the low speed range, the drive transmission link 63 is rotated in the other direction via the drive lever 61 by driving the actuator, thereby operating the synchronization mechanism 47 and the plurality of nozzle vanes. 37 is rotated synchronously in the direction of squeezing. Thereby, the flow rate of the exhaust gas supplied to the turbine impeller 13 side can be reduced, and the pressure of the exhaust gas can be increased. Therefore, even in a low speed range of the engine speed, a sufficient amount of work of the turbine impeller 13 can be ensured to exhibit high efficiency (general action of the variable nozzle unit 27).

  If thermal deformation of the variable nozzle unit 27 or tilting of the vane shafts 39 and 41 occurs during the operation of the variable displacement turbocharger 1, as shown in FIG. 2, prior to both ends E 1 a and E 1 b on one side of the nozzle vane 37. Thus, the first contact allowable convex portion 43 contacts the wall surface of the nozzle ring 29, or the second contact allowable convex portion 45 contacts the shroud ring 31 prior to both ends E2a and E2b of the other side surface of the nozzle vane 37. Will do. Thereby, the 1st contact allowable convex part 43 and the 2nd contact allowable convex part 45 are closer to the axial center C side of the vane shafts 39 and 41 rather than both front-end | tips E1a and E1b (E2a and E2b) of the side surface of the nozzle vane 37. Accordingly, the rotation load (rotation resistance) of the nozzle vane 37 when the nozzle ring 29 and / or the shroud ring 31 are in contact with the wall surface can be sufficiently reduced. In other words, even if the low wear coat is not formed on the wall surfaces of the nozzle ring 29 and the shroud ring 31 by thermal spraying or the like, it is possible to sufficiently reduce the operational astringency of the nozzle vane 37 during the operation of the variable displacement turbocharger 1 (variable). Unique action of the nozzle unit 27).

  Therefore, according to the embodiment of the present invention, it is possible to sufficiently extend the life of the variable capacity turbocharger 1 while suppressing an increase in the manufacturing cost of the variable capacity turbocharger 1.

  In addition, this invention is not restricted to description of the above-mentioned embodiment, In addition, it can implement in a various aspect. Further, the scope of rights encompassed by the present invention is not limited to these embodiments.

It is an enlarged view of the arrow I part in FIG. It is a figure explaining the effect | action of embodiment of this invention. It is sectional drawing along the III-III line in FIG. It is a front view of the variable nozzle unit which concerns on embodiment of this invention. It is a rear view of the variable nozzle unit which concerns on embodiment of this invention. It is an expanded sectional view of the arrow view part VI in FIG. 1 is a cross-sectional view of a variable capacity turbocharger according to an embodiment of the present invention.

Explanation of symbols

1 Variable displacement turbocharger 13 Turbine impeller 27 Variable nozzle unit 29 Nozzle ring (first base ring member)
31 Shroud ring (second base ring member)
39 First vane shaft 41 Second vane shaft 43 First contact allowable convex portion 45 Second contact allowable convex portion 47 Synchronization mechanism

Claims (4)

In a variable nozzle unit that varies the flow rate of exhaust gas supplied to the turbine impeller side in a variable displacement turbocharger,
A pair of base ring members provided facing each other;
Provided at equal intervals along the circumferential direction between the pair of base ring members, each rotatable about an axis parallel to the axis of the base ring member, and integrally formed on at least one side surface. And a plurality of nozzle vanes each having a vane shaft rotatably supported by the base ring member,
First contact-permitting convex portions that allow contact with the wall surface of one of the base ring members are integrally formed on both sides of the vane shaft on one side surface of each nozzle vane and only on the axial center side portion of the vane shaft. The convex surface of each first contact allowable convex portion is parallel to one side surface of the nozzle vane, and is on both sides of the vane shaft on the other side surface of each nozzle vane and on the axial center side portion of the vane shaft. Only, the second contact-permissible convex portions that allow contact with the wall surface of the other base ring member are integrally formed, and the convex surface of each second contact-permissible convex portion is parallel to the other side surface of the nozzle vane. variable nozzle unit, characterized in that it it.   The vane shaft is formed integrally with one side surface of the nozzle vane and is rotatably supported by one of the base ring members, and the other side surface of the nozzle vane is concentric with the first vane shaft. 2. The variable nozzle unit according to claim 1, wherein the variable nozzle unit is a second vane shaft that is integrally formed on the base ring member and is rotatably supported by the other base ring member.   3. The variable nozzle unit according to claim 1, further comprising a synchronization mechanism that synchronizes the rotation operations of the plurality of nozzle vanes. In a variable capacity turbocharger that uses the energy of exhaust gas from the engine to supercharge the air supplied to the engine,
A variable displacement turbocharger comprising a variable nozzle unit comprising the invention-specifying matters according to any one of claims 1 to 3.

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