JPH0341063Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a turbocharger with a variable nozzle, and in particular to a support structure for a variable nozzle that can suppress thermal deformation of the variable nozzle support part and smoothly operate the variable nozzle. Regarding.

[Prior Art] A turbocharger with a variable nozzle has been known for a long time.
-114842 publication etc. are known. Since the variable nozzle of this variable nozzle-equipped turbocharger becomes hot, it is supported by a structure as shown in FIG. In FIG. 2, reference numeral 1 indicates a variable nozzle, and the variable nozzle 1 is arranged between the turbine housing 2 and a back plate 4 forming a wall on the center housing 3 side. The shaft 1a of the variable nozzle 1 is supported by a bush 5 provided on the back plate 4 side, and the variable nozzle 1 is driven by a link 6 so as to be rotatable around an axis.

[Problems to be solved by the invention] However, in the variable nozzle support structure described above, the back plate of the variable nozzle support part is only fitted to the turbine housing, so when the turbocharger is operated, the back plate is heated. There was a problem in that the variable nozzle was deformed and protruded toward the turbine housing, and the variable nozzle was pinched between the back plate and the turbine housing, impeding the operation of the variable nozzle. Therefore, there is a problem that damage occurs due to interference between the variable nozzle and the back plate, and in some cases, the variable nozzle and the back plate are welded together, making it impossible to operate the variable nozzle.

In order to solve these problems, this invention
An object of the present invention is to provide a support structure for a variable nozzle that can suppress thermal deformation of the back plate to a small extent, prevent damage due to interference between the variable nozzle and the back plate, and improve the durability of the variable nozzle and the back plate. shall be.

[Means for Solving the Problems] The nozzle support structure of the variable nozzle-equipped turbocharger of the present invention, which meets this objective, has a plurality of In a turbocharger with a variable nozzle,
A bush that supports the shaft of each of the variable nozzles is passed through the back plate and the center housing, and this bush is composed of two divided parts consisting of a first bush and a second bush, and the first bush is attached to the back plate. By engaging the first bushing from the plate side toward the center housing side and engaging the second bushing with the center housing from the center housing side toward the back plate side, the first bushing and the second bushing are combined. It consists of a plate supported by a center housing.

[Function] In the nozzle support structure of the turbocharger with variable nozzle configured as described above, the bushing supporting the shaft of the variable nozzle is the first bushing and the second bushing.
Since the bushing has a two-part structure, the first bushing can be engaged with the back plate from the back plate side toward the center housing side, and the second bush can be engaged with the center housing from the center housing side. It becomes possible to engage toward the back plate side. That is, by connecting the first bushing and the second bushing 2, the back plate is supported by the highly rigid center housing. Therefore, even if the back plate is subjected to high heat, thermal deformation of the back plate is restrained by the support of the center housing, and the amount of deformation of the back plate is suppressed to a small amount.

[Embodiments] Hereinafter, preferred embodiments of the nozzle support structure for a turbocharger with a variable nozzle according to the present invention will be described with reference to the drawings.

FIG. 1 shows a nozzle support structure of a turbocharger with a variable nozzle according to an embodiment of the present invention. In the figure, 7 indicates a turbine housing, and the turbine housing 7 is attached adjacent to the center housing 8. A back plate 9 forming a wall on the center housing 8 side is provided between the turbine housing 7 and the center housing 8.
is provided. The back plate 9 has a large diameter hole 9a and a small diameter hole 9b at the variable nozzle shaft insertion part.
are formed coaxially with each other. The large diameter hole 9a is located closer to the turbine housing 7 than the small diameter hole 9b. A hole 8a is formed in the center housing 8 coaxially with a large diameter hole 9a and a small diameter hole 9b.

A plurality of variable nozzles 10 for adjusting the inflow speed of exhaust gas are rotatably provided between the turbine housing 7 and the back plate 9 around a shaft 10a.
It extends through the back plate 9 and the center housing 8 from the back plate 9 side toward the center housing 8 side. A bush 11 for supporting the shaft 10a of the variable nozzle 10 is provided in the hole 8a of the center housing 8 and the large diameter hole 9a and small diameter hole 9b of the back plate 9 so as to penetrate through the center housing 8 and the back plate 9. .

The bush 11 is constructed from a threaded structure in which two parts are divided into two parts in the axial direction, including a first bush 12 and a second bush 13.

A flange portion 12a that bulges radially outward is formed on the outer periphery of the end of the first bushing 12 on the turbine housing 7 side.
A threaded portion 12 is located closer to the center housing 8 than 2a.
b is formed. In the first bushing 12,
A hole 12c extending in the axial direction is formed through which the shaft 10a of the variable nozzle 10 is inserted.
On the back plate 9 side of 2c, a hole 12d larger than the hole 12c is formed in a stepped shape with respect to the hole 12c.

A hexagonal flange portion 13a for tightening that bulges outward in the radial direction is formed at the end of the second bushing 13 on the center housing 8 side. A threaded portion 13b that can be screwed together with the twelve threaded portions 12b is formed.

The first bush 12 is inserted into the large diameter hole 9 and small diameter hole 9b of the back plate 9 from the back plate 9 side toward the center housing 8 side. 9 is in contact with the stepped portion of the large diameter hole 9a. The second bush 13 is located in the center housing 8
is inserted into the hole 8a from the center housing 8 side toward the back plate 9 side, and the threaded portion 13b
is screwed into the threaded portion 12b of the first bush 2. By tightening this case, the flange portion 13a of the second bushing 13 is brought into contact with the end surface of the center housing 8, and the tip end portion 13c of the second bushing 13 is also brought into contact with the end surface of the back plate 9.

In the holes 12c and 12d of the first bushing 12,
A shaft 10a of the variable nozzle 10 is rotatably inserted. Shaft 10a of variable nozzle 10
A link 14 for operating the variable nozzle 10 is connected to the end of the variable nozzle 10, and the variable nozzle 10 can smoothly rotate around the shaft 10a depending on the operating state of the engine.

Next, the operation of the nozzle support structure of the variable nozzle-equipped turbocharger described above will be explained.

When the first bush 12 inserted from the back plate 9 side is screwed into the second bush 13 inserted from the center housing side and tightened, each bush is integrated and fixed to the back plate 9 and center housing 8. Ru. At the same time, the back plate 9 and the highly rigid center housing 8 are also fastened together. Therefore, when the back plate 9 tries to thermally deform toward the turbine housing 7, the flange portion 13a of the second bush 13 screwed into the first bush 12 is brought into contact with the highly rigid center housing 8. , deformation of the back plate 9 is suppressed by the flange portion 12a of the first bush 12. Therefore, the back plate 9 at the portion facing the variable nozzle 10
The amount of deformation is kept small, and interference between the back plate 8 and the variable nozzle 10 is prevented.

Also, the length of the second bush 13, that is,
The length from the lower surface of the flange 13a to the tip 13c that is in contact with the center housing 9 side is the second
Since it is formed to have approximately the same length as the thickness of the center housing 8 that holds the bush 13,
Excessive tightening of the second bushing 13 during assembly is prevented.

By configuring the bush 11 with a threaded structure of two divided parts, it is possible to easily adjust the tightening force of the second bush 13, and the back plate 9 can be adjusted with an appropriate tightening force. It is supported by the center housing 8.

[Effect of the invention] As explained above, in the nozzle support structure of the turbocharger with a variable nozzle of the invention, the bush that supports the shaft of each variable nozzle is
The back plate is made up of two separate parts consisting of a bush and a second bush, and the back plate is supported by the center housing by connecting the first bush and the second bush, so the amount of deformation of the back plate due to heat can be reduced. It becomes possible to suppress it. As a result, welding and damage due to interference between the back plate and the variable nozzle can be prevented, and the durability of the variable nozzle and the back plate can be improved.

Further, since the back plate is tightened by the first bush and the second bush 1, there is no gap between the bush and the back plate, eliminating air leakage from this portion.

Further, in the nozzle support structure of the present invention, only compressive stress is applied to the back plate, so it is also possible to use a material such as ceramic for the back plate.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing a nozzle support structure of a turbocharger with a variable nozzle according to an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing a nozzle support structure of a conventional turbocharger with a variable nozzle. 7... Turbine housing, 8... Center housing, 9... Back plate, 10... Variable nozzle, 11... Bush, 12... First bush, 13... Second bush.

Claims (1)

[Scope of utility model registration request] In a turbocharger having a plurality of variable nozzles between a turbine housing and a back plate constituting a wall on the center housing side of the turbine housing, a bush that supports the shaft of each variable nozzle is passed through the back plate and the center housing, The bushing is composed of two parts consisting of a first bushing and a second bushing, and the first bushing is engaged with the back plate from the back plate side toward the center housing side, and the second bush is engaged with the center housing side. A nozzle support for a turbocharger with a variable nozzle, characterized in that the back plate is supported on the center housing by engaging the first bushing and the second bushing from the center housing side toward the back plate side. structure.