JP2009243432A - Variable nozzle unit, variable capacity type turbocharger, nozzle side gap correction method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress fluctuation of performance of a variable capacity type turbocharger 1 while enhancing productivity of the variable capacity type turbocharger 1. <P>SOLUTION: A plurality of connection members 33 are arranged between a pair of base ring members 29, 31 to connect them, a plurality of nozzle vanes 37 are arranged between the pair of base ring members 29, 31 along a circumferential direction in an equally spaced manner and at least any one connection member 31 of the connection members 31 is plastically deformed by being pressed with a lateral and/or axial press. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a variable nozzle unit that varies the pressure of exhaust gas supplied to a turbine impeller side in a variable displacement turbocharger, a variable displacement turbocharger, and a nozzle side clearance correction method that corrects the nozzle side clearance of the variable nozzle unit. About.

  In recent years, a variable displacement turbocharger equipped with a variable nozzle unit that varies the pressure of exhaust gas supplied to the turbine impeller side has been developed so that high efficiency can be achieved even at low engine speeds (patent) Reference 1 and Patent Document 2). 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 connecting members are connected between the nozzle ring and 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 the shafts can be rotated. The plurality of nozzle vanes are configured to rotate synchronously while operating a synchronization mechanism by driving an appropriate actuator.

Therefore, when the engine speed is in the high speed range, the plurality of nozzle vanes are rotated in the opening direction while operating the synchronization mechanism by driving an appropriate actuator, and 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 the low speed range, the synchronizing mechanism is operated by driving an appropriate actuator, and the plurality of nozzle vanes are rotated synchronously in the direction of squeezing to be supplied to the turbine impeller side. Reduce the exhaust gas flow rate and increase the exhaust gas pressure. Therefore, even in the 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 JP 2003-27951 A

  By the way, as shown in FIG. 7, it is known that when the nozzle side gap of the variable nozzle unit determined by the dimensions of the connecting member and the nozzle vane is reduced, the efficiency (turbo efficiency) increases, and the variable capacity to be mass-produced. In order to suppress variations in the performance of the type turbocharger, it is necessary to increase the accuracy of the side gap of the variable nozzle unit and narrow the target efficiency range. On the other hand, if the accuracy of the nozzle side gap of the variable nozzle unit is to be increased, the tolerances of the connecting member and the nozzle vane must be strictly controlled, and the productivity of the variable capacity turbocharger decreases.

  That is, there is a problem that it is extremely difficult to suppress the variation in performance of the variable capacity turbocharger while increasing the productivity of the variable capacity turbocharger.

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

  According to a first aspect of the present invention, in the variable nozzle unit that varies the pressure of the exhaust gas supplied to the turbine impeller side in the variable displacement turbocharger, a pair of base ring members provided opposite to each other, A plurality of connecting members provided to be connected between the base ring members, and an axis provided between the pair of base ring members at equal intervals along the circumferential direction and parallel to the axis of the base ring member A plurality of nozzle vanes that can rotate around the center, and at least one of the plurality of connection members is plastically deformed by lateral and / or axial pressing. The gist.

  In the claims and specification of the present application, “provided” means not only directly provided but also indirectly provided via an intermediate member. The “lateral direction” is a direction orthogonal to the axial direction of the connecting 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).

  Since at least one of the plurality of connecting members is plastically deformed by lateral and / or axial pressing, the pair of base ring members are connected by the plurality of connecting members. By changing the axial length of any of the connecting members, the gap between the pair of base ring members can be adjusted to correct the nozzle side gap of the variable nozzle unit. Thereby, the tolerance of the nozzle side gap of the variable nozzle unit can be made smaller than the combination of the tolerances of the connecting member and the nozzle vane. In other words, the accuracy of the nozzle side gap of the variable nozzle unit can be sufficiently increased even if the tolerance between the connecting member and the nozzle vane is loosened (a characteristic action of the variable nozzle unit).

  According to a second aspect of the present invention, there is provided a variable displacement turbocharger that supercharges air supplied to the engine using energy of exhaust gas from the engine, comprising the variable nozzle unit having the first characteristic. This is the summary.

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

  A third feature of the present invention is a nozzle side gap correction method for correcting a nozzle side gap of a variable nozzle unit in a variable capacity turbocharger, wherein a plurality of nozzle vanes are disposed between a pair of opposed base ring members. Then, after connecting the pair of base ring members by a plurality of connecting members, at least one of the plurality of connecting members is subjected to plastic deformation by lateral and / or axial pressing, By changing the axial length of the connecting member, the distance between the pair of base ring members is adjusted to correct the nozzle side gap of the variable nozzle unit.

  In the specification and claims of the present application, the “nozzle side gap” refers to a gap between one wall surface of the base ring member and one end face of the nozzle vane, a wall surface of the other base ring member, and the nozzle vane. A gap obtained by combining the gaps of the other end surfaces of the two.

  According to the third feature, after the pair of base ring members are connected by the plurality of connecting members, plasticity is applied to at least one of the plurality of connecting members by lateral and / or axial pressing. Since the nozzle side gap of the variable nozzle unit is corrected by applying the deformation, the tolerance of the nozzle side gap of the variable nozzle unit can be made smaller than the combination of the tolerances of the connecting member and the nozzle vane. In other words, the accuracy of the nozzle side gap of the variable nozzle unit can be sufficiently increased even if the tolerance of the connecting member and the nozzle vane is loosened.

  According to the present invention, the accuracy of the nozzle side gap of the variable nozzle unit can be sufficiently increased even if the tolerances of the connecting member and the nozzle vane are loosened, thereby improving the productivity of the variable capacity turbocharger. The variation in performance of the variable capacity turbocharger can be suppressed.

  An embodiment of the present invention will be described with reference to FIGS.

  Here, FIG. 1 is a cross-sectional view of the variable nozzle unit along line II in FIG. 2, FIG. 2 is a front view of the variable nozzle unit according to the embodiment of the present invention, and FIG. 3 is an embodiment of the present invention. 4 is a rear view of the variable nozzle unit, FIG. 4 is a cross-sectional view of the variable nozzle unit in which the connecting pin is plastically deformed by a lateral press, and FIG. 5 is an enlarged cross-sectional view of the portion V in FIG. 6 is a cross-sectional view of a variable capacity turbocharger according to an embodiment of the present invention. In the drawings, “F” indicates the forward direction, and “R” indicates the backward direction.

  As shown in FIGS. 4 and 5, 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. An annular diffuser flow path 23 that pressurizes the compressed air is formed between the bearing housing 3 and the compressor housing 7 so as to surround the compressor impeller 15. The diffuser flow path 23 is formed of an air intake port. 21 is 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 pressure (flow rate and pressure) of exhaust gas supplied to the turbine impeller 13 side is provided in the turbine housing 5. The specific configuration of the variable nozzle unit 27 is as follows. become that way.

  As shown in FIGS. 1, 2, 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. Further, a shroud ring 31 as a second base ring member is provided at a position facing the nozzle ring 29 in the front-rear direction so as to surround the turbine impeller 13, and the shroud ring 31 is concentric with the nozzle ring 29. positioned. A plurality of connecting pins 33 (an example of a connecting member) are provided between the nozzle ring 29 and the shroud ring 31, in other words, one end portion (rear end portion) of each connecting pin 33. ) Are integrally connected to the nozzle ring 29, and the other end portions (front end portions) of the connection pins 33 are integrally connected to the shroud ring 31. Further, one end portion of each connecting pin 33 protrudes rearward (one direction) from the nozzle ring 29. In the illustrated example, the three connecting pins 33 are arranged at intervals along the circumferential direction of the nozzle ring 29 (the shroud ring 31), but the number of connecting pins 33 is limited to three. is not.

  A mounting ring 35 is integrally provided on the rear side of the nozzle ring 29 via a plurality of connecting pins 33 (one end portions of the plurality of connecting pins 33). It is sandwiched between the housing 5 and the bearing housing 3. In other words, the nozzle ring 29 is fixed to the bearing housing 3 via the mounting ring 35 and is provided in the turbine housing 5.

  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 has an axial center (in other words, the shroud ring 31 of the shroud ring 31). It can be rotated around an axis parallel to the axis or the axis of the turbine shaft 11. Further, a first vane shaft 39 is formed on one end surface (rear end surface) of each nozzle vane 37, and each first vane shaft 39 is rotatably supported by the nozzle ring 29. . Furthermore, a second vane shaft 41 is formed on the other end surface (front end surface) of each nozzle vane 37, and each second vane shaft 41 is rotatably supported by the shroud ring 31. .

  As shown in FIGS. 2, 3, and 5, a synchronization mechanism 43 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 45 is provided on the rear side of the nozzle ring 29 via a plurality of connecting pins 33 (one end portions of the plurality of connecting pins 33). The guide ring 45 includes a movable ring. 47 is rotatably provided. The movable ring 47 is located concentrically with the nozzle ring 29, and the same number of synchronization engaging recesses 49 as the nozzle vanes 37 are formed at equal intervals along the circumferential direction inside the movable ring 47. ing. Each first vane shaft 39 is integrally connected to the base end portion of the synchronization transmission link 51, and the distal end portion of each synchronization transmission link 51 is a corresponding synchronization engagement recess 49. Are engaged with each other.

  In addition to the plurality of synchronization engagement recesses 49, a drive engagement recess 53 is formed inside the movable ring 47. Further, as shown in FIG. 5, a drive shaft 55 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 of the drive shaft 55 is provided. A base end portion of the drive lever 57 is integrally connected to the portion (rear end portion), and an actuator (not shown) such as a cylinder is interlocked and connected to the drive lever 57. The other end portion (front end portion) of the drive shaft 55 is integrally connected to the base end portion of the drive transmission link 59, and the distal end portion of the drive transmission link 59 is engaged with the drive engagement recess 53. Yes.

  As shown in FIGS. 1 and 2, at least one of the plurality of connecting pins 33 is subjected to plastic deformation by pressing in the lateral direction (in other words, the direction orthogonal to the axial direction). Yes. Further, the connecting pin 33 that has been plastically deformed by the lateral press is extended from the initial axial length. The lateral pressing is performed between the nozzle ring 29 and the shroud ring 31 by sandwiching the side portion of the connecting pin 33 from the arrow direction in FIG. 2 by a pair of press dies (not shown). is there.

  As shown in FIG. 4, at least one of the plurality of connecting pins 33 may be plastically deformed by axial pressing, and plastic deformation may be caused by axial pressing. The applied connecting pin 33 is shortened from the initial axial length. The axial pressing is performed by holding both ends of the connecting pin 33 from the direction of the arrow in FIG. 4 by a pair of press dies (not shown) outside the nozzle ring 29 and the shroud ring 31. is there.

  One variable nozzle unit 27 may include a connecting pin 33 plastically deformed by a lateral axial press and a connecting pin 33 plastically deformed by an axial press. I do not care. Specifically, the connecting pin 33 whose initial axial length is shorter than the target value is subjected to plastic deformation by lateral pressing, so that the axial length of the connecting pin 33 is longer than the initial axial length. In addition, the connecting pin 33 whose initial axial length is longer than the target value is plastically deformed by axial pressing, so that the axial length of the connecting pin 33 is shorter than the initial axial length.

  The same connecting pin 33 may be plastically deformed by pressing in the lateral direction and the axial direction. Specifically, when the connecting pin 33 is plastically deformed by a lateral press, and the axial length of the connecting pin 33 is excessively extended, the same connecting pin 33 is plastically deformed by an axial press. As a result, the axial length of the connecting pin 33 may be finely adjusted.

  The axial center of each connecting pin 33 is located radially outside the rotation center of the nozzle vane 37 (outside in the radial direction of the nozzle ring 29 and the shroud ring 31).

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

  When the engine rotational speed is in the high speed range, the drive transmission link 59 is rotated in one direction via the drive lever 57 by driving the actuator, thereby operating the synchronization mechanism 43 and the plurality of nozzle vanes 37. Rotate synchronously in the opening direction. Thereby, the flow rate of the exhaust gas supplied to the turbine impeller 13 side is increased, and the pressure of the exhaust gas is lowered.

  On the other hand, when the engine speed is in the low speed range, the drive mechanism 57 rotates the drive transmission link 59 in the other direction via the drive lever 57 by driving the actuator, thereby operating the synchronization mechanism 43 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 is decreased, and the pressure of the exhaust gas is 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).

  In addition, since at least one of the plurality of connection pins 33 is plastically deformed by pressing in the lateral direction and / or the axial direction, the nozzle ring 29 and the shroud ring 31 are formed by the three connection pins 33. Of the connecting member 33 by changing the axial length of one of the connecting pins 33 (by extending by a lateral press or by shortening by an axial press). By changing the axial length, the gap between the pair of nozzle rings 29 and the shroud ring 31 can be adjusted, and the nozzle side gap of the variable nozzle unit 27 can be corrected. Thereby, the tolerance of the nozzle side gap of the variable nozzle unit 27 can be made smaller than the combination of the tolerances of the connecting pin 33 and the nozzle vane 37. In other words, even if the tolerances of the connecting pin 33 and the nozzle vane 37 are loosened, the accuracy of the nozzle side gap of the variable nozzle unit 27 can be sufficiently increased (characteristic action (1) of the variable nozzle unit 27).

  Further, since the axial center of each connecting pin 33 is located radially outside the rotational center of the nozzle vane 37, the press die is not brought into contact with the nozzle vane 37, so that the nozzle ring 29 and the shroud ring 31 are not in contact with each other. In FIG. 2, the side portion of the connecting pin 33 can be clamped from the direction of the arrow in FIG. This facilitates plastic deformation of the connecting pin 33 by a lateral press (characteristic action (2) of the variable nozzle unit 27).

  As described above, according to the embodiment of the present invention, the accuracy of the nozzle side gap of the variable nozzle unit 27 can be sufficiently increased even if the tolerance of the connecting pin 33 and the nozzle vane 37 is loosened. As a result, the variation in performance of the variable capacity turbocharger 1 can be suppressed. In particular, since it becomes easy to plastically deform the connecting pin by a lateral press, the productivity of the variable capacity turbocharger can be further improved.

(Modification)
As described above, in addition to capturing the invention according to the embodiment as the variable nozzle unit 27 in which any one of the connecting pins 33 is plastically deformed by pressing in the lateral direction and / or the axial direction, in the variable capacity turbocharger 1 The invention according to the embodiment can be understood as a nozzle side gap correction method for correcting the nozzle side gap of the variable nozzle unit 27.

  That is, in the nozzle side gap correction method according to the modification of the embodiment of the present invention, a plurality of nozzle vanes 37 are arranged between the nozzle ring 29 and the shroud ring 31 at regular intervals along the circumferential direction. After the nozzle ring 29 and the shroud ring 31 are connected by the connecting pin 33, any one of the plurality of connecting pins 33 is subjected to plastic deformation by lateral and / or axial pressing. By changing the axial length of the connecting pin 33, the interval between the nozzle ring 29 and the shroud ring 31 is adjusted to correct the nozzle side gap of the variable nozzle unit.

  In the nozzle side gap correction method according to the modification of the embodiment of the present invention, the same operation / effect as the unique operation / effect of the variable nozzle unit according to the embodiment of the present invention is exhibited.

  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 sectional drawing of the variable nozzle unit along the II line | wire in FIG. 2, Comprising: The shroud ring is abbreviate | omitted partially. 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 sectional drawing of the variable nozzle unit by which the plastic pin was laterally pressed by the connecting pin, Comprising: The shroud ring is partially abbreviate | omitted. It is an expanded sectional view of the arrow view part V in FIG. 1 is a cross-sectional view of a variable capacity turbocharger according to an embodiment of the present invention. It is a figure which shows the relationship between a nozzle side clearance gap and turbo efficiency.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Variable capacity type turbocharger 13 Turbine impeller 27 Variable nozzle unit 29 Nozzle ring 31 Shroud ring 33 Connecting pin 37 Nozzle vane 37 Variable nozzle unit 39 First vane shaft 41 Second vane shaft 43 Synchronization mechanism

Claims (5)

In the variable nozzle unit that varies the pressure of the exhaust gas supplied to the turbine impeller side in the variable displacement turbocharger,
A pair of base ring members provided facing each other;
A plurality of connecting members provided to connect between the pair of base ring members;
A plurality of nozzle vanes provided between the pair of base ring members at equal intervals along the circumferential direction and rotatable about an axis parallel to the axis of the base ring member;
A variable nozzle unit, wherein at least one of the plurality of connecting members is plastically deformed by pressing in a lateral direction and / or an axial direction.   2. The variable nozzle unit according to claim 1, wherein the shaft center of each connecting member is located radially outside the rotation center of the nozzle vane.   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 the variable capacity turbocharger that uses the energy of the exhaust gas from the engine to supercharge the air supplied to the engine,
A variable displacement turbocharger comprising the variable nozzle unit according to any one of claims 1 to 3. In a nozzle side gap correction method for correcting a nozzle side gap of a variable nozzle unit in a variable capacity turbocharger,
After connecting the pair of base ring members by a plurality of connecting members in a state where a plurality of nozzle vanes are disposed between the pair of opposed base ring members,
By subjecting at least one of the plurality of connecting members to plastic deformation by lateral and / or axial pressing, and changing the axial length of any of the connecting members, a pair of the bases A nozzle side gap correction method, comprising: adjusting a gap between ring members to correct a nozzle side gap of the variable nozzle unit.

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