JP2001173450A - Variable turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove exhaust gas supplied to a turbine from a back surface of a side plate by bypassing nozzle part of a variable turbocharger. SOLUTION: The nozzle part 100 of this variable turbocharger 10 is constituted by nozzle plate 102 and the side plate 104 which are separately arranged from each other in a rotation shaft direction of the turbine 28. The side plate is connected to the nozzle plate 102 by a plurality of support bolts 108 crossing the nozzle part 100. A back plate 116 which is in tight contact with an inner surface of an inner peripheral part of the side plate 106 is disposed, and the exhaust gas bypassing the nozzle part 100 through an outside of the side plate 106 is sealed by the tight contact between them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a variable turbocharger, and more particularly, to an improvement of a variable turbocharger.

[0002]

2. Description of the Related Art As means for increasing the output of an internal combustion engine,
Turbochargers that rotate a turbine with exhaust gas from an internal combustion engine and pressurize air supplied to the internal combustion engine with a compressor provided coaxially with the turbine are effective, and have already been installed in various internal combustion engines. However, since the flow rate of the exhaust gas varies depending on the engine speed of the internal combustion engine, a mismatch occurs between the flow rate of the exhaust gas actually supplied from the internal combustion engine and the flow rate of the exhaust gas that meets the optimal operating conditions of the turbocharger. In order to compensate for this inconsistency and to fully demonstrate the performance of the turbocharger, a variable turbocharger has been developed that can adjust the flow of exhaust gas in the turbine cabin of the turbocharger according to the operating state of the internal combustion engine. I have.

[0003] In such a variable turbocharger, a plurality of nozzle vanes are disposed in a nozzle portion of a turbine in a housing. FIG. 7 shows a partially enlarged sectional view of a turbine nozzle portion of a variable turbocharger according to the prior art.

[0004] In FIG. 7, a turbine 228 has a rotating shaft 232 whose housing 22 is connected to the variable turbocharger housing 22.
It is rotatably supported at zero. Exhaust gas from the internal combustion engine is introduced into the housing 220 from an intake port of the variable turbocharger, and a scroll passage 226 defined in the housing 220 and the turbine 22
8 through a nozzle section 210 forming an inlet to the turbine 2
28. The exhaust gas supplied to the turbine 228 is discharged from an exhaust port after driving the turbine 228.

[0005] The nozzle portion 210 includes a mount plate 202 fixed to a housing 220 and a support bolt 208.
And a side plate 206 attached to a mount plate 202, and a plurality of nozzle vanes 204 are disposed at equal intervals in the circumferential direction between the two. The nozzle vane 204 has its shaft portion 204a,
The shaft 204a is attached to the mount plate 202 so as to be rotatable between an open position and a closed position. The seal of the exhaust gas supplied to the turbine 228 and the heat thereof
A back plate 216 is provided for shielding the heat so as not to be transmitted to the bearing portion supporting the support 32.

[0006]

Conventionally, however, the side plate 206 has a gap between the side plate 206 and the housing 220 at a portion indicated by an arrow B in FIG. Is provided. For this reason, in the variable turbocharger according to the related art, a part of the exhaust gas supplied to the scroll passage 226 bypasses the nozzle portion 210 through the gap between the housing 220 and the outer peripheral portion of the side plate 206, so that the side plate Passing through the back side of the turbine 206, the turbine 22
8. As described above, in the related art, there is a problem that the efficiency of the variable turbocharger is reduced due to the exhaust gas supplied to the turbine 228 without passing through the nozzle unit 210.

An object of the present invention is to solve such problems of the prior art, and it is an object of the present invention to reduce or eliminate exhaust gas supplied to a turbine from a back surface of a side plate by bypassing a nozzle portion. The purpose is.

[0008]

According to a first aspect of the present invention, there is provided a turbine rotatably supported about a predetermined axis in a housing, and a turbine disposed in a nozzle portion of the turbine in the housing. A plurality of nozzle vanes connected to the plurality of nozzle vanes via a plurality of lever plates, and the rotation of the turbine in the housing for operating the nozzle vanes in a continuously synchronized manner between an open position and a closed position. A variable plate including a link plate rotatably provided around an axis and an actuator provided outside the housing and connected to the link plate via a transmission mechanism to adjust an opening degree of the nozzle vane; In a turbocharger, the nozzles are spaced apart from each other in the direction of the rotation axis of the turbine. A nozzle plate and a side plate, wherein the nozzle plate is fixed to the housing, and the side plate is connected to the nozzle plate by a plurality of support bolts traversing the nozzle portion. The variable turbocharger is
A back plate that comes into close contact with the inner surface of the inner peripheral portion of the side plate, and the inner peripheral portion of the side plate comes into close contact with the back plate,
The gist of the present invention is a variable turbocharger, wherein exhaust gas passing outside the side plate and bypassing the nozzle portion is sealed.

[0009]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. First, referring to FIG. 1, the appearance of a variable turbocharger 10 to which the present invention is applied is shown. The variable turbocharger 10 includes a turbine housing 20 and a compressor housing 40.
And a main housing 30 between the turbine housing 20 and the compressor housing 40. The turbine housing 20 is located at the intake port 2
2 and the exhaust port 24, and the compressor housing 40 includes a suction port 44 and a discharge port 42.

An actuator 50 for driving a nozzle vane, which will be described later, is provided outside the housings 20, 30, and 40. The actuator 50 uses the air pressure, in particular, the intake negative pressure of the internal combustion engine (not shown) to which the variable
2 is an actuator that reciprocates back and forth.

Next, referring to FIG. 2, a rotating shaft 32 is rotatably supported by a main housing 30, and a turbine 28 attached to one end of the rotating shaft 32 is disposed in the turbine housing 20. ing. Needless to say, a compressor impeller (not shown) provided in the compressor housing 40 is attached to the other end of the rotating shaft 32. Exhaust gas from the internal combustion engine,
The gas is introduced into the turbine housing 20 from the intake port 22, and is supplied to the turbine 28 through a scroll passage 26 defined in the turbine housing 20 and a nozzle portion 100 that forms an inlet to the turbine 28. The exhaust gas supplied to the turbine 28 is exhausted from the exhaust port 24 after driving the turbine 28.

The nozzle portion 100 is provided in the turbine housing 2.
0, and a side plate 106 attached to the mount plate 102 by support bolts 108, and a plurality of nozzle vanes 104 are arranged at equal intervals in the circumferential direction between the two.

The side plate 106 is disposed in the turbine housing 20 so as to be spaced from the nozzle plate 102 in the axial direction toward the main housing 30. The side plate 106 has an annular plate portion 106a that radially expands in a plane perpendicular to the central axis of the turbine 28.
And a cylindrical portion 106 extending from the inner edge of the plate portion 106a to the compressor side of the turbocharger 10 in the axial direction.
b, and the cylindrical portion 106b is fitted to the inner peripheral surface of the cutout portion 20b formed in the turbine housing 20. The plate portion 106a of the side plate 106 is disposed in a side plate receiving recess 20a formed inside the turbine housing 20. As described in the description of the related art, the outer peripheral surface of the plate portion 106a of the side plate 106 and the inner peripheral surface of the side plate receiving recess 20a are taken into consideration in consideration of thermal deformation of the side plate 106, particularly thermal expansion in the radial direction. A gap is provided between the surfaces, and between the outer peripheral surface of the cylindrical portion 106b of the side plate 106 and the inner peripheral surface of the notch 20b.

A back plate 11 made of a sheet metal member is provided between the main housing 30 and the turbine housing 20.
6 are provided. The back plate 116 includes an annular flange portion 116a that radially expands in a plane substantially perpendicular to the central axis of the turbine 28, and the flange portion 116a.
And a cylindrical portion 116b extending axially toward the turbine 28 from the inner edge of the cylindrical portion 116b and closely contacting the outer peripheral surface of the cylindrical portion 106b of the side plate 106, and being connected to an end of the cylindrical portion 116b opposite to the flange portion 116a. Part 116
and a ring-shaped shielding portion 116c provided substantially parallel to a. As shown in FIG. 2, the shielding portion 116c may not be parallel to the flange portion 116a, but may be slightly recessed toward the compressor. The back plate 116 sandwiches and fixes the flange portion 116 a between the main housing 30 and the turbine housing 20, prevents the exhaust gas in the turbine housing 20 from flowing out, and prevents the exhaust gas from flowing out of the turbine housing 20 from the main housing 30. Prevent heat transfer to

The nozzle vane 104 has a shaft 104a at its base end, and is attached to the mount plate 102 by the shaft 104a so as to be rotatable between an open position and a closed position. Shaft 1 of each nozzle vane 104
4a penetrates the mount plate 102 in the axial direction to form a plurality of lever plates 114 (FIGS. 3 and 4).
). Lever plate 114
Have a through hole 114b for receiving the tip portion 104b of the shaft portion 104a, and a boss or shaft portion 114a formed on the opposite side of the through hole 114b.

A cylindrical boss portion 102a is formed on the mount plate 102 on the opposite side of the nozzle portion 100. The boss portion 102a has an annular link plate 1a.
12 (see FIG. 5) is mounted so as to be rotatable about the rotation axis of the turbine 28. Link plate 112
In order to receive the shaft portion 114a of the lever plate 114, the peripheral portion of the link plate 112 has elongated holes 112d arranged at equal intervals in the circumferential direction. Further, the link plate 112 has an extension 112a protruding in a trapezoidal shape on one side in the same plane.
12a is a pair of bifurcated engagement arms 1 at its tip.
12c, and a rectangular receiving recess 112b is formed between the pair of engaging arms 112c.

Variable turbocharger 1 according to the present embodiment
0 further includes a transmission mechanism for transmitting the operation of the actuator 50 to the link plate 112. The transmission mechanism includes a rod 52 of the actuator 50,
A link member 54 (see FIG. 1) connected to the distal end of the rod 52 via the pin 50a, a swing member 120 (see FIGS. 2 and 6) connected to the link member 54, a swing member 120
And a roller member 140 and a piece 130 which are disposed between the transmission mechanism and the link plate 112 and form an engaging portion between the transmission mechanism and the link plate 112.

Referring to FIG. 6, a swinging member 120 extends along a predetermined axis O from a swinging arm 122 and one end face of the swinging arm 122, and rotates on a turbine housing 20 via a sleeve 118. A shaft 124 that is freely supported;
A connecting portion 128 provided coaxially at the tip of the shaft portion 124 and connected so as not to move relative to the link member 54;
The swing arm 122 includes a pin portion 126 extending in parallel with the shaft portion 124 from an end surface opposite to the shaft portion 124. The swing member 120 can be integrally formed of a metal material, for example, stainless steel, preferably, austenitic stainless steel. The swing member 120 is
The swing arm 122, the shaft portion 124, the connecting portion 128, and the pin portion 126 may be separately formed and welded to each other.

The piece 130 has a pair of flat plates 132 spaced apart in parallel with each other, and a central portion 134 provided between the pair of flat plates 132 and connecting the flat plates 132. The link plate 112 is provided between the pair of flat portions 132.
A circumferential groove 136 for receiving the engaging arm portion 112c is formed. Further, the piece 130 has a cutout 138 which is cutout inward from the one side in the radial direction including the central portion 134, and the opposing side surfaces form sliding surfaces parallel to each other. I have. As shown in FIG. 6, when the transmission mechanism is assembled, the notch 138 is
To receive the roller member 140 attached thereto and form the engaging portion. The bridge 130 can be formed from a metal material, for example, austenitic stainless steel.

As shown in FIG. 6, the roller member 140
Center hole 1 having an inner diameter slightly larger than the outer diameter of pin portion 126
42 is formed into a generally cylindrical shape having
Has an outer diameter slightly smaller than the interval between the sliding surfaces 138a. The roller member 140 can be formed from a metal material, for example, martensitic stainless steel.

Hereinafter, the operation of the present embodiment will be described. When the internal combustion engine operates, the pressure of the negative pressure pump of the engine is controlled by an electromagnetic valve according to the rotation speed, the accelerator opening, and the like, and is sent to the actuator 50 so that the actuator 50 operates. The rod 52 moves forward and backward (moves right and left in FIG. 1) in its axial direction. Rod 52
Operates, the link member 54 rotates about the shaft 124 of the swinging member 120 accordingly. Referring to FIG. 1, a link member 54 indicated by a solid line includes a stop member 56.
At this time, the nozzle vane 104 is in the open position which gives the largest nozzle opening. When the rotational speed of the internal combustion engine is low and the accelerator opening is small, the actuator 50 moves the rod 52 backward. When the rod 52 retreats most, the link member 5
4 moves to a position where it contacts the lower bolt 56b of the stop member 56 as shown by the dashed line, and at this time, the nozzle vane 104 is at the position giving the smallest nozzle opening.

In this manner, the linear motion of the rod 52 is converted into the rocking motion of the rocking member 120 via the link member 54, and the pin 126 of the rocking member 120 is turned into an arc around the axis O of the shaft 122. Move up. At this time, the pin 1
26 and the roller member 140
8, the link plate 112 slides in the vertical direction, that is, in the rotation axis direction of the turbine 28 in the positional relationship shown in FIG. Is rotated around the rotation axis of the turbine 28 along the outer peripheral surface of the boss 102 a of the mount plate 102. When the link plate 112 rotates, the lever plate 114 connected to the link plate 112 moves the shaft portion 104 of the nozzle vane 104.
The nozzle vane 104 rotates together with the nozzle vane 104 about a, and the nozzle vane 104 operates between its open position and the closed position.

According to the present embodiment, when the linear motion of the rod 52 is converted into the rocking motion of the rocking member 120, and this is converted into the turning motion of the link plate 112, the pin 126 of the rocking member 120 is rotated. Roller member 14 between
0, the pin 126 and the piece 130
Is reduced, the operation of the link plate becomes smooth, and the pin portion 126 and the sliding surface 138a are prevented from being worn.

As already described in the description of the prior art,
A gap is provided between the outer peripheral surface of the side plate 106 and the inner peripheral surface of the side plate receiving recess 20a in consideration of thermal deformation of the side plate 106, particularly thermal expansion in the radial direction. Therefore, in the related art, a part of the exhaust gas, which should originally flow entirely from the scroll passage 26 to the nozzle portion 100, flows from the outer peripheral surface of the side plate 106 to the inner peripheral surface of the side plate receiving recess 20a.
06 along the outer side or the back side, that is, the side surface of the side plate 106 on the main housing 30 side.
0 and is supplied to the turbine 28,
This is one cause of reducing the efficiency of the variable turbocharger 10.

According to this embodiment, the back plate 11
6, the outer peripheral surface of the cylindrical portion 116b is brought into close contact with the inner peripheral surface of the cylindrical portion 106b of the side plate 106, or
The close fitting prevents a part of the exhaust gas from bypassing the nozzle part 100. The back plate 116 can be formed by sheet processing such as sheet metal processing. By forming the back plate 116 from a thin plate, when the temperature of the back plate 116 rises, the outer peripheral surface of the cylindrical portion 116 b and the side plate 106 It is possible to flexibly deform while maintaining close contact with the inner peripheral surface of the cylindrical portion 106b. Back plate 11
6 is not a sheet metal processing, but a flange portion 116a and a cylindrical portion 1;
16b and at least a part of the shielding part 116c may be formed as separate members and welded to each other.

[Brief description of the drawings]

FIG. 1 is an external side view of a variable turbocharger to which the present invention is applied.

FIG. 2 is a sectional view of a turbine casing portion of the variable turbocharger of FIG.

FIG. 3 is a front view showing a part of the variable turbocharger shown in FIG.

FIG. 4 is a partially enlarged view of FIG. 3, showing a transmission mechanism that transmits an operation of an actuator to a link plate, and an engagement portion between the link plate and the transmission mechanism.

FIG. 5 is a plan view of a link plate.

FIG. 6 is an exploded view of a transmission mechanism for transmitting the operation of the actuator to the link plate.

FIG. 7 is a partially enlarged cross-sectional view of a nozzle portion according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Variable turbocharger 50 ... Actuator 52 ... Rod 54 ... Link member 104 ... Nozzle vane 106 ... Side plate 112 ... Link plate 116 ... Back plate 114 ... Lever plate 120 ... Swing member 130 ... Piece 140 ... Roller member

Claims (2)

[Claims] A turbine rotatably supported about a predetermined axis in a housing; a plurality of nozzle vanes disposed in a nozzle portion of the turbine in the housing; and a plurality of lever plates via a plurality of lever plates. A link plate connected to the plurality of nozzle vanes and rotatably provided around the rotation axis of the turbine in the housing for operating the nozzle vanes in a continuously synchronized manner between the open position and the closed position; A variable turbocharger having an actuator provided outside the housing and connected to the link plate via a transmission mechanism so that the opening of the nozzle vane can be adjusted, wherein the nozzle portion is in the rotation axis direction of the turbine. Nozzle plate and side plate, which are spaced apart from each other Wherein the nozzle plate is fixed to the housing, the side plate is connected to the nozzle plate by a plurality of support bolts traversing the nozzle portion, and the variable turbocharger comprises: A back plate that is in close contact with the inner surface of the inner peripheral portion of the side plate, and by tight contact between the inner peripheral portion of the side plate and the back plate, the nozzle portion passes through the outside of the side plate and passes through the nozzle portion. A variable turbocharger characterized by sealing off bypass gas. 2. The side plate includes an annular plate portion extending in a radial direction in a plane perpendicular to a center axis of the turbine, and a cylinder extending axially from an inner edge of the plate portion to a compressor side of the turbocharger. The variable turbocharger according to claim 1, wherein the cylindrical portion is fitted into an inner peripheral surface of a notch formed inside the housing.