JP2010203239A - Variable displacement exhaust turbocharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable displacement exhaust turbocharger capable of preventing the deformation of a flange of a bearing housing even if excess engine oscillation acts on, and preventing the looseness or damage of a fastening bolt for fastening a variable nozzle mechanism to the bearing housing. <P>SOLUTION: The variable displacement exhaust turbocharger includes a turbine housing 1, a turbine rotor 3, a turbine shaft 3A, a bearing 5 for supporting the turbine shaft 3A, the bearing housing 4 having the flange 4a at an outer peripheral end side, and the variable nozzle mechanism 8. The variable nozzle mechanism 8 includes a nozzle 6, a nozzle mount 7, a lever plate 11 and a drive ring 10. The bearing housing 4 and the variable nozzle mechanism 8 are connected to each other with fastening bolts B penetrating the bearing housing 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a variable displacement exhaust turbocharger configured to be able to change the blade angle of a nozzle vane.

  2. Description of the Related Art Conventionally, in a relatively small exhaust turbocharger used for a vehicle internal combustion engine or the like, exhaust gas from the engine is filled in a scroll formed in a turbine housing and provided on the inner peripheral side of the scroll. A structure is adopted in which a plurality of nozzle vanes are allowed to act on a turbine rotor provided on the inner peripheral side of the nozzle vanes. The blade angles of the plurality of nozzle vanes are configured to be variable. A radial variable displacement exhaust turbocharger having such a variable nozzle mechanism is often used (see, for example, Patent Documents 1 to 3).

  FIG. 4 shows an example of a conventional exhaust turbocharger with a variable nozzle mechanism. These drawings are partial cross-sectional views along the rotation axis. As shown in the figure, a turbocharger is provided with a thick-walled and multi-tubular turbine housing 1, and a scroll 2 is formed in a spiral shape on the outer peripheral portion on the upstream side of the turbine housing 1. . On the other hand, a radial turbine rotor 3 is provided on the inner peripheral portion of the turbine housing 1 on the upstream side. In the turbine shaft 3A to which the turbine rotor 3 is attached, the center of rotation is a rotation axis K in the drawing, and is coaxial with a compressor (not shown). Further, the turbine shaft 3 </ b> A is rotatably supported by the bearing housing 4 via the bearing 5.

  An annular recess is formed on the back surface of the bearing housing 4, and a variable nozzle mechanism 8 that is a nozzle assembly including a nozzle 6 and a nozzle mount 7 is accommodated in the recess. Here, a plurality of nozzles 6 are provided around the rotation axis K at equal intervals. The nozzle 6 is located on the inner peripheral side of the scroll 2 at the radial position of the turbine. The nozzle 6 has a nozzle vane 6a and a nozzle shaft 6b. The nozzle shaft 6 b is supported by a nozzle mount 7 fixed to the bearing housing 4 so as to be rotatable about the rotation axis K. The variable nozzle mechanism 8 can change the blade angle of the nozzle vane 6a.

The nozzle vane 6 a is disposed between the nozzle mount 7 and an annular nozzle plate 9 connected to the nozzle mount 7, and the nozzle plate 9 is fitted on the distal end side of the inner cylinder portion of the turbine housing 1.
A disk-shaped drive ring 10 is rotatably provided on the raised portion on the tip end side of the nozzle mount 7. A lever plate 11 is engaged with the drive ring 10. As shown in an enlarged view in FIG. 5, the lever plate 11 has a curved portion 11 a and an engaging protrusion 11 b, and the engaging protrusion 11 b is engaged with the groove portion 10 a of the drive ring 10.
Further, a through hole is formed along the rotation axis K on the inner peripheral side of the lever plate 11, and a fixing portion 6c formed on the tip side of the nozzle shaft 6b is inserted into the through hole.
Further, as shown in an enlarged view in FIG. 6, the nozzle ring 7 is provided on the step of the nozzle mount 7 on which the drive ring 10 is provided, and a collar P <b> 1 is provided slightly below the step. The drive ring 10 is held by the flange-shaped head of the flange P1 so as not to drop off.

  FIG. 7 shows the shape viewed from the direction of arrow A in FIG. As shown in the figure, the disk-shaped nozzle mount 7 is provided with a drive ring 10 near the center in the radial direction. A lever blade 11 is connected to the drive ring 10, and a fixing portion 6 c of the nozzle 6 is engaged with the lever plate 11 on the rotation axis K side. In the figure, twelve lever plates 11 are provided around the rotation axis K. Then, the opening degree of the nozzle 6 can be adjusted by rotating the drive ring 10.

  When the variable displacement exhaust turbocharger with a variable nozzle mechanism having the configuration described with reference to FIGS. 4 to 7 is operated, exhaust gas from the engine (not shown) enters the scroll 2 and swirls in the scroll 2. It flows into the nozzle vane 6a while circling along. The exhaust gas passes between the blades of the nozzle vane 6a, flows into the turbine rotor 3 from the outer peripheral side, flows radially toward the center side, and performs expansion work on the turbine rotor 3, and then in the axial direction. It flows along, is guided to the gas outlet, and is sent out of the machine.

In controlling the capacity of the variable displacement exhaust turbocharger, the blade angle of the nozzle vane 6a is set so that the exhaust gas flowing through the nozzle vane 6a has a required flow velocity, and the blade angle control means (not shown) is used. Change the wing angle. The reciprocating displacement of the actuator corresponding to the blade angle is transmitted to the drive ring 10, and the drive ring 10 is rotationally driven.
The rotation of the drive ring 10 causes the lever plate 11 to rotate about the nozzle shaft 6b via the engaging protrusion 11b engaged with the groove portion 10a formed on the drive ring 10, and the nozzle shaft 6b The nozzle vane 6a is rotated by the rotation, and the blade angle is changed.

JP 2008-128065 A JP 2008-215083 A US Pat. No. 2,860,827

  However, in the variable displacement type exhaust turbocharger shown in FIGS. 4 to 7, the fastening bolt B exists in the space enclosed by the turbine housing 1 and the bearing housing 4, so that the fastening bolt B becomes high temperature, and the engine If the vibration is excessive, there is a risk of bolt loosening due to thermal elongation and vibration, and further there is a risk of bolt breakage due to a decrease in strength due to temperature rise. If the fastening bolt B is loosened or broken, the fluctuation of the variable nozzle mechanism 8 increases, which may lead to breakage of the variable nozzle mechanism 8.

  SUMMARY OF THE INVENTION The present invention provides a variable displacement exhaust turbocharger that does not loosen or break a fastening bolt that fastens a variable nozzle mechanism to a bearing housing even when excessive engine vibration is applied. For the purpose.

The present invention has been made as a means for solving such a problem.
The present invention includes a turbine housing into which exhaust gas of an internal combustion engine is introduced, a turbine rotor provided in the turbine housing and driven to rotate by the exhaust gas, and one end inserted into the turbine housing. A turbine shaft to which the turbine rotor is attached, a bearing that supports the turbine shaft, a bearing housing that is connected to the turbine housing and accommodates the bearing therein, and has a flange formed on the outer peripheral end side; A variable nozzle mechanism that is fixed to the bearing housing and adjusts the flow of exhaust gas to the turbine rotor, wherein the variable nozzle mechanism includes a nozzle, a nozzle mount that holds the nozzle, and a lever that engages the nozzle. A variable displacement exhaust tab comprising a plate and a drive ring engaged with the lever plate A ball supercharger, characterized in that in the fastening member extending through the bearing housing and the bearing housing and the variable nozzle mechanism is coupled.
In this invention, when the heat in the charger chamber is transmitted to the fastening member, the heat is conducted along the axial direction of the fastening member, and the heat is transmitted to the atmosphere from the portion of the fastening member protruding from the outer wall of the bearing housing. Therefore, the fastening member functions as a transmission means for radiating the heat in the charger chamber to the outside, and the temperature of the fastening member itself is lower than that when not passing through the bearing housing, and excessive engine vibration acts. Even so, the fastening member (fastening bolt or the like) that fastens the variable nozzle mechanism to the bearing housing is less likely to be loosened or damaged. In the present invention, the charger chamber means a space enclosed by the bearing housing and the turbine housing.
Furthermore, in this invention, since the length of a fastening member becomes long, when a fastening member is fastened, the elongation of a fastening member becomes large and it is hard to produce looseness with respect to a thermal deformation.

According to the present invention, the fastening member is a fastening bolt, and a countersink hole in which a head of the fastening bolt is accommodated is formed on the turbine housing side on the outer peripheral end side of the nozzle mount, and the bearing housing Is characterized in that a through hole is formed on the same axis as the countersink hole, and a nut is attached to a tip of the fastening bolt inserted through the countersink hole and the through hole.
In this invention, since the nozzle mount and the flange portion of the bearing housing are sandwiched between the head of the fastening bolt in the charger chamber and the nut outside the charger chamber, deformation of the flange portion of the bearing housing being bent forward of the turbocharger is suppressed. Thus, the load applied to the turbine housing can be reduced.

The present invention is further characterized in that the thickness of the incomplete screw portion of the fastening bolt is made thinner than that of a fastening bolt of the same size as a standard product.
In such an invention, compared with a fastening bolt of the same size as a standard product, the extension / contraction of the bolt with respect to vibration is increased, and vibration energy is easily absorbed. Here, standard products are JIS standards (Japan), DIN standards (Germany), BS standards (UK), CSA standards (Canada), NF standards (France) and GB standards (China), It shall widely include standards of specific industries or specific organizations.

The present invention further includes a flange connecting the nozzle mount and the bearing housing, the flange being inserted into a through hole of the bearing housing when assembled, and a male screw at least at one end of the flange. One end of the flange is fixed to the nozzle mount, and a nut is screwed and fastened to the other end of the flange protruding from the bearing housing.
In this invention, since the long hook is passed through the through hole of the bearing housing, the hook can be greatly stretched when the nut is tightened. Thereby, loosening of the wrinkles due to thermal deformation is unlikely to occur. Therefore, the highly reliable nozzle mount and bearing housing can be fastened.
Moreover, in this invention, the shear force and bending force which generate | occur | produce in the wrinkles by the thermal expansion of a nozzle mount can be reduced by making the position of a wrinkle into the side near the center side of a nozzle mount. Here, the scissors refer to bolts, screws, pins, other rod-like members, or combinations thereof, and widely include those formed with flanges or the like.
In this invention, since the soot is penetrated through the bearing housing, the heat transmitted or conducted in the turbocharger can be transmitted to the outside along the axial direction of the soot, and the heat deformation of the soot is suppressed. Is done.
In the first place, the rod is for holding the drive ring of the variable nozzle mechanism so as not to drop off.

The present invention is further characterized in that the flange is formed with a flange portion for restricting the axial movement of the drive ring.
In this invention, since the flange part which controls the movement of the axial direction of the said drive ring is formed in the collar, the drop-off from the nozzle mount of a drive ring can be prevented.

  In the variable displacement exhaust turbocharger according to the present invention, the flange of the bearing housing is not deformed even when excessive engine vibration is applied, and the fastening bolt that fastens the variable nozzle mechanism to the bearing housing does not loosen or break. .

FIG. 1 is an explanatory view showing a first embodiment of a variable capacity exhaust turbocharger of the present invention. FIG. 2 is an explanatory view showing a second embodiment of the variable displacement exhaust turbocharger of the present invention. FIG. 3 is an explanatory view showing a form of the variable displacement exhaust turbocharger of FIG. 2 viewed in another cross section. FIG. 4 is an explanatory view showing a conventional variable displacement exhaust turbocharger. FIG. 5 is an enlarged view showing the vicinity of the nozzle mount of FIG. FIG. 6 is an enlarged view of the vicinity of the nozzle mount of FIG. FIG. 7 is an explanatory diagram showing a form viewed from the direction of arrow A in FIG.

  Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings. However, the dimensions, materials, shapes, relative positions, and the like of the component parts described in this embodiment are not intended to limit the scope of the present invention to that unless otherwise specified.

[First Embodiment]
FIG. 1 shows a first embodiment of a variable displacement exhaust turbocharger according to the present invention. This figure is a partial cross-sectional view along the rotational axis K. As shown in the figure, a turbocharger is provided with a thick multi-tubular turbine housing 1 into which exhaust gas of an internal combustion engine is introduced, and inside the turbine housing 1 is spirally formed. A scroll 2 is formed. Further, inside the turbine housing 1, a radial turbine rotor 3 that is rotationally driven by exhaust gas is provided. The turbine rotor 3 is provided at one end of the turbine shaft 3A. One end of the turbine shaft 3 </ b> A is inserted into the turbine housing 1. The rotation center of the turbine shaft 3A is a rotation axis K in the drawing, and is coaxial with a compressor (not shown). Further, the turbine shaft 3 </ b> A is rotatably supported by the bearing housing 4 via the bearing 5.

An annular recess is formed on the back surface of the bearing housing 4, and the nozzle 6, the nozzle mount 7 that holds the nozzle 6, the nozzle plate 9, the drive ring 10, and the nozzle 6 and the drive ring 10 are engaged with the recess. A variable nozzle mechanism 8 is provided as a nozzle assembly including the lever plate 11 and the like. The variable nozzle mechanism 8 is fixed to the bearing housing 4 and has a function of adjusting the flow of exhaust gas.
A plurality of nozzles 6 are provided around the rotation axis K at equal intervals. The nozzle 6 is located on the inner peripheral side of the scroll 2 at the radial position of the turbocharger. The nozzle 6 has a nozzle vane 6a and a nozzle shaft 6b. The nozzle shaft 6 b is supported by a nozzle mount 7 fixed to the bearing housing 4 so as to be rotatable about the rotation axis K. In the variable nozzle mechanism 8, the blade angle of the nozzle vane 6a can be changed.

The nozzle vane 6 a is disposed between the nozzle mount 7 and an annular nozzle plate 9 coupled to the nozzle mount 7, and the nozzle plate 9 is fitted on the distal end side of the inner cylinder portion 1 a of the turbine housing 1. Yes.
A disk-shaped drive ring 10 is rotatably provided on the raised portion on the tip end side of the nozzle mount 7. A lever plate 11 is engaged with the drive ring 10.
Further, a through hole is formed along the rotation axis K on the inner peripheral side of the lever plate 11, and a fixing portion 6c formed on the tip side of the nozzle shaft 6b is inserted into the through hole.

  When the variable displacement exhaust turbocharger with the variable nozzle mechanism having the above-described configuration is operated, exhaust gas from the engine (not shown) enters the scroll 2 and circulates along the spiral of the scroll 2 to the nozzle vane 6a. Inflow. The exhaust gas passes between the blades of the nozzle vane 6a, flows into the turbine rotor 3 from the outer peripheral side, flows radially toward the center side, and performs expansion work on the turbine rotor 3, and then in the axial direction. It flows along, is guided to the gas outlet, and is sent out of the machine.

In controlling the capacity of the variable displacement exhaust turbocharger, the blade angle of the nozzle vane 6a is set so that the exhaust gas flowing through the nozzle vane 6a has a required flow velocity, and the blade angle control means (not shown) is used. Change the wing angle. The reciprocating displacement of the actuator corresponding to the blade angle is transmitted to the drive ring 10, and the drive ring 10 is rotationally driven.
The lever ring 11 engaged with the drive ring 10 is rotated about the nozzle shaft 6b by the rotation of the drive ring 10, and the nozzle vane 6a is rotated by the rotation of the nozzle shaft 6b. Changes.

  In the present embodiment, a countersink hole 7 a that houses the head of the fastening bolt B that is a fastening member is formed on the turbine housing side on the outer peripheral end side of the nozzle mount 7. A through hole 4b is formed on the same axis as the counter hole 7a, and a nut N is attached to the tip of the fastening bolt B inserted through the counter hole 7a and the through hole 4b.

  In this configuration, the nozzle mount 7 and the flange 4a of the bearing housing 4 are sandwiched between the head of the fastening bolt B in the charger chamber enclosed by the bearing housing 4 and the turbine housing 1 and the nut N outside the charger chamber. Deformation such that the flange portion 4a of the bearing housing 4 is bent forward of the supercharger is suppressed, and the load applied to the turbine housing 1 can be reduced. Further, since the fastening bolt B is penetrated through the bearing housing 4, even if heat in the charger chamber is transmitted or conducted to the fastening bolt B, the heat can be released to the outside of the charger chamber, and the thermal deformation of the fastening bolt B is achieved. Is suppressed. For this reason, the fastening bolt B is unlikely to be loosened or damaged. Furthermore, in this embodiment, since the length of the fastening bolt B is increased, the elongation of the fastening bolt B at the time of bolt fastening is increased, and it is difficult for loosening to occur due to thermal deformation.

[Second Embodiment]
2 and 3 show a second embodiment of the variable displacement exhaust turbocharger of the present invention. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.
In the present embodiment, a nail pin P <b> 1 is provided as a rod that connects the nozzle mount 7 and the bearing housing 4. The nail pin P1 is inserted through the through hole of the bearing housing 4 when assembled. A male screw is formed on the end of the nail pin P1 on the bearing housing insertion side. The other end side of the nail pin P1 is press-fitted into the nozzle mount 7. Here, screwing or other fixing may be used instead of press-fitting. A nut N is screwed to the other end of the nail pin P1 protruding from the bearing housing 4, and the nozzle mount 7 and the bearing housing 4 are fastened by tightening the nut. Moreover, since the flange part P1a which controls the movement of the axial direction of the drive ring 10 is formed in the nail pin P1 of this embodiment, the drop-off from the nozzle mount 7 of the drive ring 10 can be prevented. Specifically, since the nail pin P1 protrudes radially outward from the inscribed ring of the drive ring 10, the movement of the drive ring 10 is restricted. The flange portion P1a corresponds to the flange-shaped head portion of the flange P1 described in the background art with reference to FIG.

In the present embodiment, since the long nail pin P1 is passed through the through hole of the bearing housing 4, the nail pin P1 can be greatly stretched when the nut is tightened. Thereby, the nail pin P1 is hardly loosened due to thermal deformation. Therefore, the highly reliable nozzle mount 7 and the bearing housing 4 can be fastened.
Further, in the present embodiment, the nail pin P <b> 1 is generated on the nail pin P <b> 1 due to the thermal expansion of the nozzle mount 7 by setting the position of the nail pin P <b> 1 closer to the center side of the nozzle mount 7 than when the nail pin P <b> 1 is disposed on the outer peripheral side of the nozzle mount 7. Shear force and bending force can be reduced. In the present embodiment, an example in which the nail pin P1 is used as a bag has been described, but the present invention is not limited to this. For example, a bolt, a screw, a pin, other rod-shaped members, or a combination of these can be used as the rod. Moreover, the thing in which the flange etc. were formed shall be included widely.
Moreover, in this embodiment, since the nail pin P1 is penetrated to the bearing housing 4, the heat transmitted or conducted in the turbocharger can be transmitted to the outside along the axial direction of the soot. Thermal deformation is suppressed.

Although the present invention has been described above, the present invention is not limited to the above-described embodiments, and it goes without saying that other various modifications are possible without departing from the essence thereof.
For example, in the embodiment described above, a bolt having a standard diameter is used as the fastening bolt B, but the thickness of the incomplete screw portion of the fastening bolt B is smaller than the thickness of the fastening bolt of the same size as the standard product. May be. In this way, the bolts are more stretched and shrunk with respect to vibration than standard fastening bolts, and vibration energy is easily absorbed.

  In the variable displacement exhaust turbocharger according to the present invention, the flange of the bearing housing is not deformed even when excessive engine vibration is applied, and the fastening bolt that fastens the variable nozzle mechanism to the bearing housing does not loosen or break. . The configuration of the characterizing portion of the present invention can be applied to the entire turbocharger including the turbine housing, the bearing housing, and the nozzle mount.

DESCRIPTION OF SYMBOLS 1 Turbine housing 1a Inner cylinder part 2 Scroll 3 Turbine rotor 3A Turbine shaft 4 Bearing housing 4a collar part 4b Through-hole 5 Bearing 6 Nozzle 6a Nozzle vane 6b Nozzle shaft 6c Fixed part 7 Nozzle mount 7a Countersink hole 8 Variable nozzle mechanism 9 Nozzle plate 10 Drive ring 10a Groove part 11 Lever plate 11a Bending part 11b Engaging protrusion B Fastening bolt K Rotating shaft center N Nut P1 Nail pin P1a Flange part

Claims (5)

A turbine housing into which exhaust gas of the internal combustion engine is introduced;
A turbine rotor provided in the turbine housing and driven to rotate by exhaust gas;
A turbine shaft having one end inserted into the turbine housing and the turbine rotor attached to the one end;
A bearing supporting the turbine shaft;
A bearing housing connected to the turbine housing and housing the bearing therein, and having a flange formed on the outer peripheral end;
A variable nozzle mechanism fixed to the bearing housing for adjusting the flow of exhaust gas to the turbine rotor;
With
The variable nozzle mechanism includes a nozzle, a nozzle mount that holds the nozzle, a lever plate that engages with the nozzle,
A drive ring engaged with the lever plate;
A variable capacity exhaust turbocharger comprising:
A variable displacement exhaust turbocharger, wherein the bearing housing and the variable nozzle mechanism are coupled by a fastening member penetrating the bearing housing. The fastening member is a fastening bolt;
On the turbine housing side on the outer peripheral end side of the nozzle mount, a countersink hole for accommodating the head of the fastening bolt is formed,
The bearing housing has a through hole formed on the same axis as the counterbore,
The variable capacity exhaust turbocharger according to claim 1, wherein a nut is attached to a tip of the fastening bolt inserted through the counterbore and the through hole.   3. The variable displacement exhaust turbocharger according to claim 2, wherein a thickness of the incomplete screw portion of the fastening bolt is smaller than a thickness of a fastening bolt of the same size as a standard product.   A flange that connects the nozzle mount and the bearing housing is provided, and the flange is inserted into a through hole of the bearing housing when assembled, and a male screw is formed at least at one end of the flange. 2. The variable displacement exhaust turbocharger according to claim 1, wherein one end is fixed to the nozzle mount, and a nut is screwed and fastened to the other end of the rod protruding from the bearing housing. Machine.   The variable capacity exhaust turbocharger according to claim 4, wherein a flange portion for restricting movement of the drive ring in the axial direction is formed on the saddle.

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