JPH1037754A - Variable nozzle turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable nozzle turbocharger which has a nozzle vane opening/closing mechanism with little abrasion and stable operation. SOLUTION: A variable nozzle turbocharger has a guide 23 composed of an arcuate hole or groove formed on a unison ring 13 and a stopper 24 fixed to a static member and projected into the guide 23. When the stopper 24 is abutted against one end in the longitudinal direction of the guide 23, a full open position of a nozzle vane 17 is shown. When the stopper 24 is abutted against the other end in the longitudinal direction of the guide 23, a full close position of the nozzle vane 17 is shown.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbocharger having a variable opening nozzle (hereinafter referred to as a variable nozzle turbocharger).

[0002]

2. Description of the Related Art A variable nozzle turbocharger is known, for example, from JP-A-62-139931. As shown in FIG. 9, the opening and closing structure of the nozzle vane in the conventional variable nozzle turbocharger rotates the nozzle vane 2 through the arm 2 fixed to the nozzle vane by rotating the unison ring 1,
The nozzle vanes are provided with stoppers 3 and 4 provided on both sides of the nozzle vane and fixed to the nozzle plate, which is a stationary member, so that the nozzle vane can be fully opened and fully closed. The unison ring 1 is rotatably supported by a plurality of rollers 5 provided in contact with the inner peripheral side thereof, and has a center of rotation.

[0003]

However, the conventional variable nozzle turbocharger has the following problems. Since the open / close position of the nozzle vane is determined by contacting the arm and the stopper, the line contact portion that hits the stopper of the arm is likely to be worn due to engine vibration or exhaust pulsation to the nozzle vane. As the position of the unison ring is supported by pins or rollers on the inside of the unison ring, when the pin or roller position and the inner diameter position of the unison ring change due to the difference in thermal expansion, if the gap is reduced at low temperatures, warm In some cases, there is no gap and the stick is concerned. Conversely, when the gap is just right during warming, the gap becomes too large at low temperatures to promote wear and unstable operation. However, when the relationship of thermal expansion is reversed, the phenomenon is also reversed. Since the unison ring stopper structure and the unison ring centering support structure are separate structures, the number of parts is increased, the number of assembling steps is increased, and the cost is increased. The object of the present invention is to make it possible to reduce the degree of undulation of the nozzle vane opening / closing position due to wear of members, to maintain an appropriate gap even at low temperatures and at warm times, to be able to support the centering of the stopper and the unison ring with the same member, It is an object of the present invention to provide a variable nozzle turbocharger capable of satisfying at least one of the above.

[0004]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a plurality of nozzle vanes rotatably supported by a stationary member of a turbocharger, and a plurality of nozzle vanes which are rotatable integrally with the nozzle vanes on a rotating shaft of the nozzle vanes. A plurality of fixed arms, a unison ring engaged with the arms so as to simultaneously change the opening of all the nozzle vanes via the arms when rotating about the ring center, and the unison ring formed on the unison ring. A guide formed of an arc-shaped hole or groove having an arc centered on a ring center; and at least one guide fixed to a stationary member of the turbocharger and entering the guide.
A stopper having a plurality of pins, and a stopper for projecting a fully open position of the nozzle vane when hitting one end of the guide and projecting a fully closed position of the nozzle vane when hitting the other end of the guide. Consists of

In the variable nozzle turbocharger according to the present invention, the open / close position of the nozzle vane is set by contact between the end of the guide formed of a hole or a groove and the stopper having a pin. The ability to convert to surface contact, and to reduce the collision speed at the contact surface due to the inertia of the unison ring, reduce the wear of the contact portion with the stopper of the guide to the contact portion with the stopper of the conventional arm. Wear can be reduced as compared with wear, and the roundness of the opening / closing position of the nozzle vane due to wear is reduced. In addition, the stopper is inserted into the guide, so that the stopper slides or rolls on the curved side on the arc center side of the guide hole or groove when the temperature is low. By setting the gap between the guide and the stopper so that the stopper slidably or rollably contacts the curved side of the groove outside the arc, a large gap is generated both at low temperature and at warm time. Instead, the unison ring can be rotatably supported by the stopper. As a result, an increase in wear and operation instability caused by a large gap are suppressed. Also,
The mechanism consisting of the stopper and the guide doubles as the nozzle vane opening / closing positioning mechanism and the unison ring center positioning mechanism, eliminating the need for a separate mechanism as in the past, reducing the number of parts and assembling. Improvement and cost reduction can be achieved.

[0006]

Embodiments of the present invention will be described below. 1 to 7 show a first embodiment of the present invention, and FIG. 8 shows a part of the second embodiment of the present invention which is different from the first embodiment of the present invention. Portions common to the first and second embodiments of the present invention are denoted by the same reference numerals in both embodiments.

First, portions common to the first and second embodiments of the present invention will be described with reference to, for example, FIGS. As shown in FIGS. 1 to 3, the variable nozzle turbocharger according to the embodiment of the present invention includes a stationary member including a turbine housing 10, a bearing housing 11, a nozzle plate 12, and the like. A turbine impeller 18 is arranged in the turbine housing 10, and a compressor impeller 19 is arranged in the compressor housing. Turbine impeller 18 and compressor impeller 19
Are connected by a rotating shaft 20, and the rotating shaft 20 is rotatably supported from a bearing housing 11 via a bearing.

The variable nozzle turbocharger according to the embodiment of the present invention is disposed on the inlet side of a turbine impeller 18 and supported by a nozzle plate 12 which is a stationary member of the turbocharger so as to be rotatable around a rotation shaft 16. Nozzle vanes 17, a plurality of arms 15 fixed to the rotation shaft 16 of the nozzle vanes 17 so as to rotate integrally with the nozzle vanes 17, and all the nozzle vanes 17 are opened via the arms 15 when rotating around the center of the ring. And a unison ring 13 slidably and / or rotatably engaged with the arm 15 so as to change the degree simultaneously. A rotating piece 14 is connected to the unison ring 13 so as to be rotatable around a rotating piece rotating center. A forked portion is formed on one of the rotating piece 14 and the arm 15, and the other of the rotating piece 14 and the arm 15 where the forked portion is not formed is slidably held by the forked portion. I have it. The nozzle plate 12 divides an engine exhaust passage in which the nozzle vanes 17 are arranged, and a chamber in which the unison ring 13 and the arm 15 are arranged.
2 is inserted.

The rotation drive mechanism of the unison ring 13 has a rotation shaft 22 rotatably supported by the bearing housing 11, and is fixed to one end of the rotation shaft 22 and rotates integrally with the rotation shaft 22. A drive arm 21 that is rotated by an actuator (not shown), an arm 15A that is fixed to the other end of the rotation shaft 22 and rotates integrally with the rotation shaft 22, and is rotatably connected to the unison ring 13. And a turning piece 14A slidably and rotatably engaged with the arm 15A. The engagement between the arm 15A and the rotating piece 14A is based on the engagement between the arm 15 and the rotating piece 14. In this mechanism, the rotation shaft 22 is rotated by the actuator, the arm 15A is rotated about the rotation shaft 22, and the unison ring 13 is rotated.

The variable nozzle turbocharger according to the embodiment of the present invention further includes a hole formed in the unison ring 13 and extending in an arc shape with the unison ring rotation center (also the ring center) as the center of the arc (the thickness of the unison ring 13 is set to the thickness). The guide 23 includes a guide plate 23 which penetrates in a direction, a illustrated example shows a hole) or a groove (a plate which does not penetrate the unison ring 13 in a thickness direction), and a nozzle plate 12 which is a stationary member of a turbocharger. And bearing housing 1
1 and a stopper 24 having at least one pin extending between the nozzle plate 12 and the bearing housing 11. The stopper 24 is inserted into the guide 23, and for example, passes through the guide 23. A plurality of combinations of the stopper 24 and the guide 23 are provided in the circumferential direction of the unison ring 13 (for example, 3 sets).
Set or more). Stopper 24
Is fixed to a stationary member and is stationary, but the guide 23 moves relative to the stopper 24,
Side of the hole or groove slidably comes into contact with the stopper 24 (including a case where there is a minute gap allowing sliding between the side of the hole or groove of the guide 23 and the stopper 24). Stopper 24
Is located at the fully open position of the nozzle vane 17 when it comes into contact with one end 23a in the longitudinal direction of the arcuate guide 23 (see FIG. 4), and is fully closed at the other end 23b in the longitudinal direction of the arcuate guide 23. (See FIG. 5), the relationship between the arc length and position of the guide 23 and the position of the stopper 24 is set in advance.

As shown in FIG. 6, a plurality of stoppers 24 may be inserted through one guide 23. In this way, the rotation angle of the unison ring 13 can be easily selected by selecting the interval between the stoppers 24 at both ends of the plurality of stoppers 24. As a result, the rotation of the unison ring 13 is changed to the opening / closing position of the nozzle vane 17. Can be easily matched.

Further, as shown in FIG. 7, the end of the guide 23 is shaped so as to come into surface contact with the stopper 24 when it comes into contact with the stopper 24. For example, when the stopper 24 is formed of a pin having a circular cross section, the ends 23a, 2
Reference numeral 3b denotes a shape in which two arcs Ri and Ro having the same radius R as the stopper 24 and having a 1/4 circumference are connected by a linear portion having a length e. By this surface contact, a load can be received in a larger area than in the case of line contact, the load applied to a unit area is reduced, and the wear of the guide 23 and the deformation of the end are greatly reduced.

The reason why the straight portion e is provided between the two arcs Ri and Ro is that the guide 23 and the stopper 2 are formed by the difference in thermal expansion between the unison ring 13 and the rotating shaft 15 of the arm 15.
This is because the unison ring is relatively displaced in the radial direction between the unison ring 4 and the unison ring 4. That is, when the temperature is low (immediately after the engine is started and the turbocharger is not warmed up yet), the unison ring 13 and the nozzle plate 12 are at substantially the same temperature, but when the engine is warmed up (the turbocharger is sufficiently warmed up). The nozzle plate 12 that comes in contact with the high-temperature exhaust gas is
The temperature is higher than 3, and the stopper 24 is displaced outward in the radial direction of the unison ring in the guide 23, so that the stopper 24 escapes.

As shown in FIG. 7, when the temperature is low, the stopper 24 is in sliding contact with the inner side 23c of the guide 23 (the side closer to the center of the arc of the guide). In the warm state, the stopper 24 makes sliding contact with the outer side 23d of the guide 23 (the side opposite to the arc center side of the guide arc) (smooth sliding is performed). The position of the stopper 24 and the guide 23 in the unison ring radial direction is set so as to include a minute gap necessary for the operation. However, when the relationship of thermal expansion is reversed, the phenomenon is also reversed.

Next, components specific to each embodiment of the present invention will be described. In the first embodiment of the present invention, the stopper 24 comprises a pin, which is
And extends between the bearing housing 11 in parallel with the axis of the turbocharger. The outer peripheral surface of the pin slidably contacts the inner surface of the guide 23. In the second embodiment of the present invention, the stopper 24 includes a pin and a roller 25 rotatably fitted on the outer periphery of the pin, and the pin extends between the nozzle plate 12 and the bearing housing 11 so as to be a turbocharger. It extends parallel to the axis. The outer peripheral surface of the roller 25 slidably contacts the inner surface of the guide 23.

Next, the operation will be described. The operation common to both embodiments of the present invention will be described. In the variable nozzle turbocharger according to the present invention, the guide 23 comprising a hole or a groove is used.
The end portions 23a and 23b of the nozzle vane 17 and the stopper 24 having a pin bring the nozzle vane 17 into the fully open and fully closed positions. Then, the shape of the contact surface is set so that the contact surface makes contact with the contact surface (in the illustrated example, an arc surface having the same radius).
Thus, the hit is changed from conventional line contact to surface contact. As a result, the load receiving area increases, and the load per unit area decreases. In addition, since the inertia of the unison ring 13 is large, the collision speed between the guide 23 and the stopper 24 at the contact surface is reduced. This also makes it possible to reduce the wear of the contact portion of the guide 23 with the stopper 24 as compared with the conventional wear of the contact portion with the stopper of the arm, and reduces the roundness of the opening and closing position of the nozzle vane due to the wear. You.

Further, the stopper 24 is inserted into the guide 23, and the stopper 24 is slidably or rollably contacted with the side 23c on the arc center side of the hole or groove of the guide 23 at a low temperature. Since the stopper 24 is slidably or rollably in contact with the outer side 23d of the arc of the hole or groove of the guide 23 at the time of warming, the guide 23 and the stopper 24 are kept at the time of low temperature and at the time of warming. The unison ring 13 can be rotatably supported by the stopper 24 stably without generating a large gap between them (the gap e is small). As a result, an increase in wear and operation instability caused by a large gap are suppressed.

In addition, a single type of mechanism including the stopper 24 and the guide 23 serves both as a mechanism for positioning the nozzle vane 17 fully open and fully closed and a mechanism for supporting the unison ring 13 at the center position. As described above, there is no need to provide a separate mechanism, so that the number of parts can be reduced, an assembly factory can be reduced, and costs can be reduced.

The operation unique to each embodiment of the present invention will be described. In the first embodiment of the present invention, since the stopper 24 is formed of a pin, there is no gap between the pin and the roller as compared with the case where the stopper is formed of a pin and a roller.
The positioning accuracy of the fully closed position increases. However, since the contact between the stopper 24 and the guide 23 becomes a sliding contact and does not involve a rotating contact, the rotation of the unison ring 13 is slightly heavier than in the case of a pin and a roller. On the other hand, in the second embodiment of the present invention, the stopper 24 is
5, there is a gap between the pin and the roller as compared with the case where only the pin is provided, so that the positioning accuracy of the fully opened and fully closed nozzle vanes 17 is slightly reduced. However, since the contact between the stopper 24 and the guide 23 is a rolling contact, the rotation of the unison ring 13 is lighter than in the case where only the pins are used.

[0020]

According to the variable nozzle turbocharger of the present invention, the guide is formed in the unison ring, and the stopper fixed to the stationary member enters the guide, so that at least one of the following can be satisfied. it can. The contact between the stopper and the guide can be easily brought into surface contact, whereby the roundness of the nozzle vane opening / closing position due to wear of the member can be reduced. A structure that can maintain an appropriate gap at both a low temperature and a warm time, thereby stabilizing the operation of the unison ring. The centering of the stopper and unison ring can be supported by the same member, thereby reducing the number of assembly steps.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view (along line 1-1 in FIG. 3) of a variable nozzle turbocharger according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view (along line 2-2 in FIG. 3) of the variable nozzle turbocharger according to the first embodiment of the present invention.

FIG. 3 is a front view of the variable nozzle turbocharger according to the first embodiment of the present invention, in which the opening degree of the nozzle vanes is halfway.

FIG. 4 is a front view of the variable nozzle turbocharger according to the first embodiment of the present invention with the nozzle vanes fully opened.

FIG. 5 is a front view of the variable nozzle turbocharger according to the first embodiment of the present invention with the nozzle vanes fully closed.

FIG. 6 is a front view of the unison ring and the stopper of the variable nozzle turbocharger according to the first embodiment of the present invention when a plurality of stoppers are provided in one guide.

FIG. 7 is a front view of the guide and stopper of the variable nozzle turbocharger according to the first embodiment of the present invention, in a state where the guide end and the stopper are in contact with each other.

FIG. 8 is a sectional view of a stopper of the variable nozzle turbocharger according to the first embodiment of the present invention.

FIG. 9 is a partial front view of a unison ring, an arm, and a stopper of a conventional variable nozzle turbocharger.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Turbine housing 11 Bearing housing 12 Nozzle plate 13 Unison ring 14 Rotating piece 15 Arm 16 Rotating shaft 17 Nozzle vane 23 Guide 23a, 23b Guide end 24 Stopper 25 Roller

Claims (1)

[Claims] A plurality of nozzle vanes rotatably supported by a stationary member of a turbocharger; a plurality of arms fixed to a rotation axis of the nozzle vane so as to rotate integrally with the nozzle vane; A unison ring engaged with the arm so as to simultaneously change the opening of all the nozzle vanes via the arm when moving, an arc-shaped hole or groove formed in the unison ring and having the ring center as the center of the arc A guide comprising at least one pin fixed to a stationary member of the turbocharger and entering the guide, and when hitting one end of the guide, takes out the fully open position of the nozzle vane and the other end of the guide. A variable nozzle turbocharger comprising: a stopper that projects a fully closed position of the nozzle vane when hit.