JP2010096110A - Turbocharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbocharger capable of preventing exhaust gas from leaking through a clearance between a nozzle ring and a bearing housing and improving efficiency of turbine operation. <P>SOLUTION: This turbocharger is provided with the bearing housing 2 for supporting a turbine impeller 23 rotatably and an exhaust nozzle 5 for changing flow rate of exhaust gas to be supplied into the turbine impeller 23. In this variable displacement turbocharger having an exhaust gas introducing wall 52 provided on a bearing housing 2 side, the exhaust nozzle 5 has a sealing member 63 being like a ring and sealing a clearance S3 formed between the bearing housing 2 and the exhaust gas introducing wall 52. This turbocharger has a configuration that an inner peripheral fringe part 63a of the sealing member 63 is pressed in the bearing housing 2 and an outer peripheral fringe part 63b of the sealing member 63 is pressed in the exhaust gas introducing wall 52. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

 The present invention relates to a turbocharger that supercharges air supplied to an engine using the energy of exhaust gas discharged from the engine, and more particularly to a variable displacement turbocharger.

Conventionally, a variable capacity turbocharger that can improve the performance of an engine over a wide range from a low rotation range to a high rotation range is known.
Here, Patent Document 1 discloses a variable capacity turbocharger.

The turbocharger has a structure in which a turbine housing and a compressor housing are integrally connected via a bearing housing, and a turbine impeller provided in the turbine housing and a compressor impeller provided in the compressor housing are connected. It is connected by a rotating shaft provided rotatably in the bearing housing.
The turbine housing is provided with an exhaust gas inlet, and the exhaust gas flowing in from the inlet is introduced into a turbine scroll passage in the turbine housing. On the turbine housing side of the bearing housing, there is provided a variable nozzle unit (exhaust nozzle) that guides the exhaust gas introduced into the turbine scroll passage to the turbine impeller and makes the flow rate variable.
The variable nozzle unit includes a shroud ring that is an exhaust introduction wall on the turbine housing side and a nozzle ring that is an exhaust introduction wall on the bearing housing side, and the nozzle ring and the shroud ring are connected in a state having a predetermined interval. ing. Between the nozzle ring and the shroud ring, a plurality of nozzle vanes for adjusting the flow rate of the exhaust gas are annularly arranged.

A predetermined gap is provided between the shroud ring of the variable nozzle unit and the turbine housing. This gap is essentially unnecessary, but is provided because the turbine housing undergoes thermal deformation between the cold time and the hot time, and the relative positional relationship with the shroud ring changes.
However, since the exhaust gas in the turbine scroll passage leaks to the outlet side of the turbine housing through the gap and reduces the turbine efficiency of the turbocharger, the turbine is removed from the inner peripheral edge of the shroud ring to close the gap. A sealing C-ring is disposed between the outer peripheral surface of the extending portion that has a substantially cylindrical shape that extends toward the housing and the inner peripheral surface of the turbine housing that faces the outer peripheral surface of the extending portion. The C-ring is formed of an elastic body, and can follow the thermal deformation of the turbine housing by its elastic force.
Japanese Patent Laying-Open No. 2006-125588 (page 14, FIG. 1)

On the other hand, a predetermined gap is also provided between the nozzle ring of the variable nozzle unit and the turbine housing to absorb a change in the position relative to the nozzle ring due to thermal deformation of the turbine housing.
Since this gap communicated with the turbine scroll flow path, the exhaust gas flowed into the gap, passed through the gap between the nozzle ring and the bearing housing, and leaked to the turbine impeller installation location.
Here, a shielding plate which is a ring-shaped flat plate is installed between the nozzle ring and the bearing housing. However, this shielding plate does not have a function of actively shielding the gap between the nozzle ring and the bearing housing, and the exhaust impeller leaks from the gap so that the turbine impeller is installed through the variable nozzle unit. There was a problem that the flow of exhaust gas introduced into the location was disturbed, resulting in a decrease in turbine efficiency of the turbocharger.

 The present invention has been made in view of such circumstances, and provides a turbocharger capable of preventing exhaust gas from leaking from a gap between a nozzle ring and a bearing housing and improving turbine efficiency. The purpose is to do.

In order to solve the above problems, the present invention employs the following means.
A turbocharger according to the present invention includes a bearing housing that rotatably supports a turbine impeller, and an exhaust nozzle that varies a flow rate of exhaust gas supplied to the turbine impeller, and the exhaust nozzle is an exhaust provided on the bearing housing side. A variable capacity turbocharger having an introduction wall has a ring-shaped seal member that shields a gap formed between the bearing housing and the exhaust introduction wall, and the inner peripheral edge of the seal member is crimped to the bearing housing. And the structure that the outer peripheral edge part of a sealing member is crimped | bonded to the exhaust introduction wall is employ | adopted.
In the present invention employing such a configuration, the inner peripheral edge and the outer peripheral edge of the ring-shaped seal member are respectively crimped to the bearing housing and the exhaust introduction wall, so that the gap between the bearing housing and the exhaust introduction wall is It is shielded, and leakage of exhaust gas from the gap can be prevented. Therefore, it is possible to keep the exhaust gas flowing in the installation location of the turbine impeller through the variable nozzle unit without disturbing the flow.

Moreover, the turbocharger of this invention employ | adopts the structure that a sealing member is a disk spring.
In the present invention employing such a configuration, since the disc spring has an elastic force, the inner peripheral edge portion and the outer peripheral edge portion of the disc spring can be pressed against the bearing housing and the exhaust introduction wall, respectively. In the present invention, even if the bearing housing and the exhaust introduction wall are thermally deformed due to the heat of the exhaust gas, the disk spring can follow the thermal deformation because of the elastic force.

Further, the turbocharger of the present invention employs a configuration in which the outer peripheral edge of the disc spring has a curved portion that curves toward the side away from the exhaust introduction wall.
In the present invention that employs such a configuration, the outer peripheral edge portion has a curved portion, so that it can uniformly contact the exhaust introduction wall in the circumferential direction of the disc spring, and the exhaust gas from the contact portion can be contacted. Leakage can be reliably prevented.

The turbocharger of the present invention employs a configuration in which a heat shield plate that is a ring-shaped flat plate is disposed on the turbine impeller side of the bearing housing, and the disc spring is installed between the heat shield plate and the bearing housing. .
In the present invention employing such a configuration, the heat shield plate prevents the heat of the exhaust gas introduced into the installation location of the turbine impeller from being transmitted to the disc spring, so that it is possible to prevent thermal deterioration of the disc spring.

Further, in the turbocharger of the present invention, a protrusion protruding toward the turbine impeller side from the surface of the bearing housing facing the turbine impeller is fitted to the inner peripheral edge of the heat shield plate, and the heat shield plate and the bearing housing are disc springs. The structure which clamps the inner peripheral part of this is employ | adopted.
In the present invention adopting such a configuration, the heat shield plate and the bearing housing sandwich the inner peripheral edge of the disc spring, so that the exhaust gas can be reliably prevented from leaking from the sandwiching section.

According to the present invention, the following effects can be obtained.
According to the present invention, the exhaust gas can be prevented from leaking from the gap between the nozzle ring and the bearing housing, so that the turbine efficiency of the turbocharger can be improved.

Hereinafter, a turbocharger according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing the overall configuration of a turbocharger 1 according to the present embodiment, FIG. 2 is an enlarged view of the periphery of the variable nozzle unit 5 in FIG. 1, and FIG. 3 is a schematic diagram of a disc spring 63 in the present embodiment. (A) is a plan view of the disc spring 63, and (b) is a sectional view taken along line XX of (a). In addition, the arrow F in the said drawing shows a front direction.

First, the overall configuration of the turbocharger 1 according to the present embodiment will be described with reference to FIG.
As shown in FIG. 1, a turbocharger 1 according to this embodiment is a variable capacity turbocharger that supercharges air supplied to an engine using energy of exhaust gas guided from an engine (not shown). .
The turbocharger 1 includes a bearing housing 2, a turbine housing 3 connected to the front peripheral edge of the bearing housing 2 by fastening bolts 2a, and a compressor housing 4 connected to the rear peripheral edge of the bearing housing 2 by fastening bolts 2b. It has.

 A turbine shaft 21 extending in the front-rear direction is rotatably supported in the bearing housing 2 via a bearing 22. A turbine impeller 23 is integrally connected to the front end portion of the turbine shaft 21, and a compressor impeller 24 is integrally connected to the rear end portion. The turbine impeller 23 is installed in the turbine housing 3, and the compressor impeller 24 is installed in the compressor housing 4.

 A variable nozzle unit (exhaust nozzle) 5 having a substantially annular shape is installed inside the turbine housing 3 and outside the turbine impeller 23 in the radial direction.

The turbine housing 3 includes a turbine scroll passage 31 provided on the radially outer side of the turbine impeller 23 and a turbine housing outlet 32 that is an exhaust gas exhaust port.
The turbine scroll passage 31 is formed in a substantially annular shape surrounding the turbine impeller 23 and communicates with a gas inlet (not shown) for introducing exhaust gas. Further, the turbine scroll channel 31 communicates with a later-described nozzle channel 5 </ b> A in the variable nozzle unit 5. The gas inlet is connected to an exhaust port in an engine (not shown).
The turbine housing outlet 32 opens to the front side of the turbine housing 3, and communicates with the nozzle flow path 5 </ b> A through the installation location of the turbine impeller 23. The turbine housing outlet 32 is connected to an exhaust gas purification device (not shown).

The compressor housing 4 is formed with an intake port 41 that opens to the rear side and is connected to an air cleaner (not shown). Further, between the bearing housing 2 and the compressor housing 4, a diffuser flow path 42 that compresses and pressurizes air is formed in a substantially annular shape on the radially outer side of the compressor impeller 24. In addition, the diffuser flow path 42 communicates with the intake port 41 through the installation location of the compressor impeller 24.
Further, the compressor housing 4 has a compressor scroll passage 43 formed in a substantially annular shape on the radially outer side of the compressor impeller 24, and the compressor scroll passage 43 communicates with the diffuser passage 42. The compressor scroll passage 43 communicates with an intake port in an engine (not shown).

Next, the configuration of the variable nozzle unit 5 will be described with reference to FIGS.
As shown in FIG. 2, the variable nozzle unit 5 includes a shroud ring 51 installed on the turbine housing 3 side, and a nozzle ring (exhaust introduction wall) 52 installed on the bearing housing 2 side facing the shroud ring 51. And a plurality of nozzle vanes 53 held between the shroud ring 51 and the nozzle ring 52. The nozzle flow path 5 </ b> A is formed between the shroud ring 51 and the nozzle ring 52.

 The shroud ring 51 has a shape in which a substantially cylindrical extending portion 51 </ b> E extending toward the turbine housing outlet 32 is connected to an inner peripheral edge of a plate-like member formed in a substantially ring shape. The shroud ring 51 is formed with a plurality of first holes 51a that penetrates in the thickness direction of the plate-like member.

 The nozzle ring 52 is a plate-like member formed in a substantially ring shape, and has a plurality of second hole portions 52a penetrating in the thickness direction.

As shown in FIG. 1, the shroud ring 51 and the nozzle ring 52 are connected via a plurality of connecting pins 57 so as to form a predetermined interval. The connecting pin 57 penetrates the shroud ring 51 and penetrates the nozzle ring 52 to protrude rearward.
A mounting ring 58 is integrally provided on the rear side of the nozzle ring 52 via a connecting pin 57, and an outer peripheral edge portion of the mounting ring 58 is sandwiched and supported by the turbine housing 3 and the bearing housing 2. ing. That is, the nozzle ring 52 is supported by the bearing housing 2 and the turbine housing 3 via the attachment ring 58.

A plurality of nozzle vanes 53 are provided at equal intervals in the circumferential direction between the nozzle ring 52 and the shroud ring 51, and are each rotatable about an axis parallel to the rotation axis of the turbine impeller 23.
Each nozzle vane 53 includes a nozzle vane main body 54 that is a plate-like member having a substantially rectangular shape, a first vane shaft 55 protruding from one side of the nozzle vane main body 54, and a second vane shaft 56 protruding from a side opposite to the one side. Have.
The first vane shaft 55 is rotatably inserted into the first hole 51 a of the shroud ring 51, and the second vane shaft 56 is rotatably passed through the second hole 52 a of the nozzle ring 52 and the nozzle ring 52. Protrudes to the rear side.

 As shown in FIG. 2, a gap S <b> 1 is formed between the shroud ring 51 and the turbine housing 3 to absorb relative movement with respect to the shroud ring 51 when the turbine housing 3 undergoes thermal deformation. In order to prevent the exhaust gas from leaking from the gap S1, two sheets for shielding the gap S1 are provided between the outer peripheral surface of the extending portion 51E of the shroud ring 51 and the inner peripheral surface of the turbine housing 3. A C-ring 61 is provided.

 Further, a second gap S <b> 2 is formed between the nozzle ring 52 and the turbine housing 3 for absorbing relative movement with respect to the nozzle ring 52 when the turbine housing 3 undergoes thermal deformation. Further, a third gap S3 is formed between the nozzle ring 52 and the bearing housing 2, and the third gap S3 communicates with the second gap S2 and opens at a place where the turbine impeller 23 is installed. Communicate.

 A heat shield plate 62 is provided between the bearing housing 2 and the turbine impeller 23 to prevent the heat of the exhaust gas introduced into the installation location of the turbine impeller 23 from being transmitted to the bearing housing 2 side. The heat shield plate 62 is a plate-like member that surrounds the turbine shaft 21 and has a ring shape. A protrusion 2B that protrudes forward from the facing surface 2A of the bearing housing 2 that faces the turbine impeller 23 is formed on the inner peripheral edge thereof. The outer peripheral edge is in contact with the inner peripheral surface of the nozzle ring 52.

A disc spring (seal member) 63 is provided on the rear side of the heat shield plate 62, that is, on the opening portion of the third gap S3 with respect to the installation location of the turbine impeller 23.
As shown in FIG. 3, the disc spring 63 is a plate-like member formed in a ring shape, and the inner peripheral edge portion 63 a and the outer peripheral edge portion 63 b of the disc spring 63 are displaced with respect to the central axis direction of the disc spring 63. A spring member having a shape and having an elastic force in the direction of the central axis.

As shown in FIG. 2, the protrusion 2 </ b> B of the bearing housing 2 passes through the central opening of the disc spring 63, and the inner peripheral edge 63 a of the disc spring 63 is opposed to the heat shield plate 62 and the facing surface 2 </ b> A of the bearing housing 2. It is clamped without gaps. On the other hand, the outer peripheral edge 63b of the disc spring 63 is in contact with the second facing surface 52B of the nozzle ring 52 facing the bearing housing 2 without any gap.
Here, the disc spring 63 is disposed between the nozzle ring 52 and the bearing housing 2 in a compressed state from its natural length (the length when no load is applied). The peripheral edge 63 a is pressed against the facing surface 2 A of the bearing housing 2, and the outer peripheral edge 63 b of the disc spring 63 is pressed against the second opposing surface 52 B of the nozzle ring 52.

Next, the configuration of the synchronization mechanism 7 that rotates each nozzle vane 53 in the present embodiment in synchronization will be described with reference to FIG.
As shown in FIG. 1, on the rear side of the variable nozzle unit 5, a synchronization mechanism 7 for rotating each nozzle vane 53 in synchronization is provided.
The synchronization mechanism 7 has an annular shape surrounding the turbine impeller 23 and is connected to the second vane shaft 56 of each nozzle vane 53. The synchronization mechanism 7 is connected to an actuator such as a cylinder (not shown) for operating the synchronization mechanism 7 via a drive shaft 71 and a drive lever 72.

Next, the operation of the turbocharger 1 according to this embodiment will be described.
First, the operation of supercharging the air supplied to the engine using the energy of the exhaust gas of the turbocharger 1 will be described.

Exhaust gas discharged from the exhaust port of the engine is introduced into the turbine scroll passage 31 through the gas inlet of the turbine housing 3. Subsequently, the exhaust gas is introduced from the turbine scroll passage 31 into the nozzle passage 5A.
At this time, each nozzle vane 53 is rotated by the operation of an actuator (not shown) and the synchronization mechanism 7 according to the number of revolutions of the engine, that is, the flow rate of exhaust gas introduced into the nozzle channel 5A, and the opening area of the nozzle channel 5A To change. The flow rate of the exhaust gas passing through the nozzle flow path 5A is adjusted by the change in the opening area, and as a result, the engine performance can be improved over a wide range from the low rotation range to the high rotation range.
The exhaust gas that has passed through the nozzle flow path 5A is introduced into the installation location of the turbine impeller 23, and rotates the turbine impeller 23. Thereafter, the exhaust gas is discharged from the turbine housing outlet 32.

Since the turbine impeller 23 is connected to the compressor impeller 24 via the turbine shaft 21, the compressor impeller 24 rotates as the turbine impeller 23 rotates.
As the compressor impeller 24 rotates, the air introduced from the intake port 41 is supplied to the diffuser flow path 42. The air is compressed and pressurized by passing through the diffuser flow path 42. The pressurized air is supplied to the intake port of the engine through the compressor scroll passage 43. As a result, the engine can be supercharged with air and the engine output can be improved.
Thus, the supercharging operation of the turbocharger 1 is completed.

Next, the operation in which the disc spring 63 shields the opening with respect to the installation location of the turbine impeller 23 in the third gap S3 will be described.
Since the second gap S2 communicates with the turbine scroll flow path 31 and the third gap S3 communicates with the second gap S2, the exhaust gas passes from the turbine scroll flow path 31 through the second gap S2 to the third gap S3. Flow into.

Here, since the disc spring 63 is installed between the nozzle ring 52 and the bearing housing 2, the disc spring 63 shields the opening portion of the third gap S <b> 3 with respect to the installation location of the turbine impeller 23.
Therefore, the disc spring 63 prevents the exhaust gas flowing into the third gap S3 from leaking to the installation location of the turbine impeller 23. As a result, the flow of the exhaust gas introduced into the installation location of the turbine impeller 23 through the variable nozzle unit 5 can be maintained in an organized state without being disturbed.
Further, even if the nozzle ring 52 and the bearing housing 2 are thermally deformed by the heat of the exhaust gas, the disk spring 63 can follow the thermal deformation because of the elastic force.

 The heat shield plate 62 prevents the heat of the exhaust gas introduced into the installation location of the turbine impeller 23 from being transmitted to the disc spring 63, so that the elastic force of the disc spring 63 is lost by heat (so-called thermal deterioration). Can be prevented.

Therefore, according to the present embodiment, the following effects can be obtained.
In the present embodiment, since exhaust gas can be prevented from leaking from the gap between the nozzle ring 52 and the bearing housing 2, there is an effect that the turbine efficiency of the turbocharger 1 can be improved.

 Note that the operation procedures shown in the above-described embodiment, or the shapes and combinations of the components are examples, and can be variously changed based on process conditions, design requirements, and the like without departing from the gist of the present invention. is there.

 For example, in the above-described embodiment, the disc spring 63 is employed as a seal member that shields the gap between the nozzle ring 52 and the bearing housing 2, but the seal member is a member having an elastic force in the front-rear direction. For example, a member having a bellows-like substantially cylindrical shape that expands and contracts in the front-rear direction may be used.

Further, in the above embodiment, the outer peripheral edge 63b of the disc spring 63 is crimped to the second facing surface 52B of the nozzle ring 52 at its end edge, but as shown in FIG. You may have the curved part 63c which curves to the side spaced apart from 52. As shown in FIG.
FIG. 4 is a schematic view showing another configuration of the disc spring 63.
By adopting such a configuration, the curved portion 63c can be formed so as to be in uniform contact with the second opposing surface 52B of the nozzle ring 52 in the circumferential direction of the disc spring 63. Exhaust gas leakage can be reliably prevented.

1 is a schematic diagram illustrating an overall configuration of a turbocharger 1 according to the present embodiment. FIG. 2 is an enlarged view around a variable nozzle unit 5 in FIG. 1. It is the schematic of the disc spring 63 in this embodiment. 6 is a schematic view showing another configuration of the disc spring 63. FIG.

Explanation of symbols

 DESCRIPTION OF SYMBOLS 1 ... Turbocharger, 2 ... Bearing housing, 2A ... Opposite surface, 2B ... Projection, 5 ... Variable nozzle unit (exhaust nozzle), 23 ... Turbine impeller, 52 ... Nozzle ring (exhaust introduction wall), 62 ... Heat shield 63 ... Disc spring (seal member), 63a ... Inner peripheral edge, 63b ... Outer peripheral edge, 63c ... Curved part

Claims (5)

A bearing housing that rotatably supports the turbine impeller, and an exhaust nozzle that makes the flow rate of exhaust gas supplied to the turbine impeller variable. The exhaust nozzle has an exhaust introduction wall provided on the bearing housing side. In variable capacity turbochargers,
A seal member that has a ring shape and shields a gap formed between the bearing housing and the exhaust introduction wall;
The turbocharger, wherein an inner peripheral edge of the seal member is crimped to the bearing housing, and an outer peripheral edge of the seal member is crimped to the exhaust introduction wall.  The turbocharger according to claim 1, wherein the seal member is a disc spring.  3. The turbocharger according to claim 2, wherein an outer peripheral edge portion of the disc spring has a curved portion that curves toward a side away from the exhaust introduction wall.  3. A heat shield plate, which is a ring-shaped flat plate, is disposed on the turbine impeller side of the bearing housing, and the disc spring is installed between the heat shield plate and the bearing housing. 3. The turbocharger described in 3.  A protrusion projecting from the surface of the bearing housing facing the turbine impeller toward the turbine impeller is fitted to the inner peripheral edge of the heat shield plate, and the heat shield plate and the bearing housing are located inside the disc spring. The turbocharger according to claim 4, wherein the peripheral portion is sandwiched.

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