JP2014111904A - Turbocharger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turbocharger having a simpler structure to suppress the accumulation of esterified deposits on and near a sliding member which drives a variable nozzle.SOLUTION: A turbocharger 1 including a variable nozzle 63 has a storage space 15 formed by both of a bearing side housing 13 and an exhaust side housing 12, where a turbine impeller 22 and the variable nozzle 63 are stored, and it also has a sliding member 41 inserted through the outside of at least one of both housings to the inside of the storage space 15 for driving the variable nozzle 63. On at least a portion of the surface of the sliding member 41, an oil-repellent fluororesin layer is formed.

Description

  The present invention relates to a turbocharger having a variable nozzle.

An internal combustion engine mounted on a vehicle or the like in recent years is a turbocharger equipped with a variable nozzle capable of supercharging from a very low rotation region such as idling for the purpose of reducing the size and weight, improving the output and fuel consumption. The installed ones are increasing. Various proposals have been made for sliding portions of variable nozzle drive mechanisms in turbochargers having variable nozzles.
For example, in the prior art described in Patent Document 1, in a variable capacity supercharger in which the capacity of a turbine is variable by a variable nozzle mechanism, a sliding member that is in sliding contact with a mating member among members constituting the variable nozzle mechanism. A surface treatment structure of a variable capacity supercharger is described in which a carbon-based dry film is formed on one or both of two adjacent members forming a surface and a minute gap to reduce sliding resistance. .
Further, in the prior art described in Patent Document 2, physical vapor deposition consisting of Al, Cr, Si, and N on austenitic stainless steel as a base material is used as a pin for setting the blade angle of the nozzle vane of the variable nozzle mechanism. A turbocharger is described which uses highly wear-resistant pins coated with a hard coating.

JP 2004-138005 A JP 2008-95541 A

Depending on the structure of the internal combustion engine, even in Patent Literature 1 and Patent Literature 2, there is a case where the slidability of the drive mechanism of the variable nozzle cannot be sufficiently maintained. For example, some diesel engines include a fuel addition valve, a turbocharger, an oxidation catalyst, and a DPF (Diesel particulate filter) that collects particulate matter in the exhaust gas in the exhaust gas path. In such a diesel engine, fuel is added from the upstream side of the turbocharger in the exhaust gas path in order to regenerate the DPF collection capability, and the fuel stirred and homogenized by the turbocharger is oxidized on the oxidation catalyst. The temperature of the exhaust gas is raised by reaction, the particulate matter on the DPF is incinerated, the DPF clogging is prevented, and the collection ability is regenerated.
Soot, oil, unburned fuel, etc. contained in exhaust gas leaking from a slight gap in the sliding member that drives the variable nozzle when DPF regeneration with fuel added from the upstream of the turbocharger is performed in the exhaust gas path As a result, the esterified deposit may stick and deposit. As the deposit amount increases, the operation of the sliding member for driving the variable nozzle is affected.
Neither Patent Document 1 nor Patent Document 2 takes into consideration the fact that the sliding member that drives the variable nozzle and the esterified deposit accumulates in the vicinity of the sliding member. Neither a carbon-based dry film that reduces sliding resistance (Patent Document 1) nor a hard film that improves wear resistance (Patent Document 2) is an effective measure for depositing esterified deposits.
The present invention was devised in view of such a point, and a simpler structure in which esterified deposits are deposited in the vicinity of a sliding member that drives a variable nozzle and the sliding member. It is an object of the present invention to provide a turbocharger that can be suppressed at the same time.

In order to solve the above problems, the turbocharger according to the present invention takes the following means.
A first aspect of the present invention is a turbocharger including a variable nozzle, wherein the turbocharger is housed in a housing space formed by both the bearing-side housing and the exhaust-side housing. A sliding member that is inserted into the housing space from at least one outer side of both housings to drive the variable nozzle, and at least a part of the surface of the sliding member has oil repellency. A turbocharger in which a fluororesin layer is formed.

In the first aspect of the invention, a fluororesin layer having oil repellency is formed on at least a part of the surface of the sliding member that drives the variable nozzle.
As a result, even if the esterified deposit is fixed to the sliding member, the deposit is not firmly fixed to the sliding member by the fluororesin layer having oil repellency. Can be peeled off with low load. Therefore, it is possible to suppress the deposition of esterified deposits on the sliding member that drives the variable nozzle with a simpler structure.

  Next, according to a second aspect of the present invention, there is provided a turbocharger including a variable nozzle, wherein the turbocharger includes a turbine impeller and the variable nozzle in a housing space formed by both the bearing side housing and the exhaust side housing. At least one of the two housings that is accommodated and has a sliding member that is inserted from at least one outside of the two housings into the inside of the accommodating space and drives the variable nozzle, and that is in contact with or close to the sliding member. A turbocharger in which a fluororesin layer having oil repellency is formed on at least a part of one surface.

In the second aspect of the invention, a fluororesin layer having oil repellency is formed on at least a part of at least one surface of both housings in contact with or close to the sliding member.
Thus, by forming the fluororesin layer at an appropriate location, it is possible to suppress the deposit of esterified deposits in the vicinity of the sliding member and the sliding member with a simpler structure. it can.

It is the schematic explaining the whole structure of a turbocharger. It is a perspective view explaining the example of the mechanism which drives a variable nozzle in a turbocharger. It is sectional drawing explaining the circumference | surroundings of a 3rd link (equivalent to a sliding member) and a 3rd link, and is a figure explaining the example of the position which forms a fluororesin layer. It is a perspective view of the 3rd link, and is a figure explaining other examples in the position which forms a fluororesin layer.

EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated using drawing.
● [Overall structure of turbocharger 1 (Figs. 1 and 2)]
First, the overall structure of the turbocharger 1 will be described with reference to the schematic diagram of FIG.
The turbocharger 1 includes a turbine shaft 23, an intake side impeller 21, an exhaust side impeller 22 (corresponding to a turbine impeller), an intake side housing 11, an exhaust side housing 12, a bearing side housing 13, a variable nozzle 63, and the like. As a mechanism for driving the variable nozzle 63, the actuator 50, the power transmission member (the first link 53, the second link 43, the third link 41, the turning ring 42), the opening of the variable nozzle 63 (the amount of operation of the actuator 50). Is provided with an opening degree detection means 51 and the like. The third link corresponds to a sliding member.

An intake side impeller 21 is provided at one end of the turbine shaft 23 in the axial direction, and an exhaust side impeller 22 is provided at the other end of the turbine shaft 23.
The intake-side housing 11 covers the periphery of the intake-side impeller 21 and directs the intake-side inlet 31A into which air from an air cleaner or the like flows and the air supercharged by the intake-side impeller 21 to the engine (corresponding to an internal combustion engine). Are connected to the intake side outlet 31B.
The exhaust-side housing 12 covers the periphery of the exhaust-side impeller 22 and directs the exhaust-side inlet 32A into which exhaust gas from the engine flows, and the exhaust gas after the exhaust-side impeller 22 is rotationally driven to a purification device such as the DPF 70. Are connected to the exhaust outlet 32B.
In addition, a DPF 70 that collects particulate matter in the exhaust gas is provided at the tip of the exhaust side outlet 32B, and the exhaust side inlet 32A is used to raise the temperature to regenerate the collection capability of the DPF 70. A fuel addition valve 71 for adding fuel is provided. In this embodiment, an oxidation catalyst is supported on the DPF 70.
The bearing-side housing 13 rotatably supports the turbine shaft 23 and covers the periphery of the turbine shaft 23. One end in the axial direction is connected to the intake-side housing 11 and the other end is connected to the exhaust-side housing 12. .

The variable nozzle 63 is provided in the exhaust side housing 12 or the rear end of the bearing side housing 13 and adjusts the area of the flow path from the exhaust side inflow port 32 </ b> A to the exhaust side impeller 22.
The exhaust side impeller 22 and the variable nozzle 63 are accommodated in an accommodation space 15 formed by both the bearing side housing 13 and the exhaust side housing 12.
The actuator 50 is, for example, an electric motor, is provided in the intake side housing 11, and drives the variable nozzle 63 via a power transmission member (the first link 53, the second link 43, the third link 41, the turning ring 42). .
The opening degree detecting means 51 is a sensor for detecting the opening degree of the variable nozzle 63. For example, the opening degree detecting means 51 detects the operation amount (rotation angle, etc.) of the actuator 50 and indirectly detects the opening degree of the variable nozzle 63. To do.

Next, the power transmission member (the first link 53, the second link 43, the third link 41, the turning ring 42) and the like will be described with reference to FIG. FIG. 2 is a perspective view in which a part of the bearing-side housing 13 is omitted for explanation.
The bearing-side housing 13 is provided with a variable nozzle 63 that can turn around the exhaust-side impeller 22 and the support shaft 63A. A driven arm 63B is connected to the support shaft 63A, and the driven arm 63B is engaged with the turning ring 42. When the swivel ring 42 is swung to the (open side) or (closed side) in FIG. 2, the support shaft 63A is swung via the driven arm 63B, and the respective variable nozzles 63 are swung. By changing the interval, the area of the flow path of the exhaust gas is adjusted.
Further, in the bearing side housing 13, the turning shaft portion 41 </ b> A of the third link 41 is inserted into the through hole 13 </ b> K (see FIG. 3), and the driving arm 41 </ b> C is connected to the turning shaft portion 41 </ b> A. Is engaged. The rotational power of the actuator 50 is transmitted to the third link 41 via the first link 53 and the second link 43, and the third link 41, the drive arm 41C, and the turning ring 42 are turned around the turning shaft portion 41A. Then, the variable nozzle 63 is turned.

● [Position of fluororesin layer (Fig. 3)]
Next, the position of the fluororesin coating (formation position of the fluororesin layer) will be described with reference to FIG. 3 showing a cross-sectional view around the third link 41.
As shown in FIG. 1, the fuel added (injected) from the fuel addition valve 71 provided at the exhaust side inlet 32A is agitated and uniformed by the exhaust side impeller 22 and discharged to the exhaust side outlet 32B. The DPF 70 reaches the DPF 70 and burns at the position of the DPF 70 to raise the temperature of the DPF 70 and regenerate the particulate matter collecting ability of the DPF 70.

Here, as shown in FIGS. 1 and 3, the third link 41, which is one of the power transmission members that drive the variable nozzle, is inserted from the outside of the bearing-side housing 13 to the inside of the accommodation space 15. Therefore, a through-hole 13K (see FIG. 3) that communicates the outside and the inside of the bearing-side housing 13 is formed at this position.
Therefore, as shown in FIG. 3, a minute gap is formed between the through hole 13K and the third link 41, and a small amount of soot, oil, unburned fuel, etc. in the exhaust gas passes through this gap on the bearing side. There is a possibility of leakage from the inside of the housing 13 to the outside.
In particular, when the temperature of the third link 41 in the gap is around 200 [° C.], the adhesion of the deposit in which the unburned fuel component is esterified is almost maximized, and the deposit turns the third link 41. This deposit may be firmly fixed to the surface of the shaft portion 41A, and this deposit may be deposited. As the fixed deposit accumulates, the turning shaft portion 41A of the third link 41 may eventually be fixed in the through hole 13K, so that the deposit is not fixed to the third link 41, or even if the deposit is the first Even if it adheres to the three links 41, it must be peeled off (relatively easily) with a low load.
Therefore, in order to avoid that the deposit is firmly fixed, a coating having oil repellency is applied in advance to the portion where the deposit is fixed. Note that in this embodiment, the coating having oil repellency is coated with a fluororesin in consideration of heat resistance (a fluororesin layer is formed).
By coating with a fluororesin having oil repellency, the deposit is prevented from sticking to the third link 41 (to make it difficult to stick). Even if the deposit is fixed to the third link 41, the fixing force is reduced due to the oil repellency of the fluororesin layer. it can.

Various positions can be considered as the positions where the fluororesin is coated. For example, in FIG. 3, the sliding surface 41 </ b> H that is in contact with or close to the inner wall of the through-hole 13 </ b> K in the turning shaft 41 </ b> A of the third link 41. What is necessary is just to coat a fluororesin on the surface. In this case, at least a part of the surface of the third link 41 is coated, but the entire surface of the third link 41 may be coated with a fluororesin.
As another position, as shown in FIG. 3, a fluororesin may be coated on the inner wall surface 13 </ b> H that is in contact with or close to the turning shaft portion 41 </ b> A on the inner wall of the through hole 13 </ b> K of the bearing-side housing 13. In this case, the third link 41 inserted through the through-hole 13K and the bearing-side housing 13 including the inner wall of the through-hole 13K are in contact with or close to the surface, and the surface of the third link 41 or the bearing side At least a part of the surface of the housing 13 is coated with a fluororesin (a fluororesin layer is formed on at least a part).
Further, as shown in FIG. 4, in the third link 41 having the turning shaft portion 41A and the arm 41B, the surface 41M of the turning shaft portion 41A and the surface 41N on the turning shaft portion 41A side of the arm member 41B are made of fluororesin. May be coated. In this case, at least a part of the third link 41 is coated with a fluororesin (a fluororesin layer is formed on at least a part).

As described above, the turbocharger 1 described in the present embodiment affects the sliding of the third link 41 by adhering deposits esterified with unburned fuel around the third link 41 and the third link 41. Depositing deposits can be suppressed with a very simple structure of coating a fluororesin having oil repellency (forming a fluororesin layer) at a place where there is a possibility of the effect.
Thereby, the malfunction of the 3rd link 41 can be prevented beforehand.

The turbocharger 1 of the present invention is not limited to the configuration, structure, operation, etc. described in the present embodiment, and various modifications, additions, and deletions can be made without changing the gist of the present invention.
Various fluororesins can be used for coating, but those having higher heat resistance are preferred.
Moreover, although the coating method of a fluororesin is not specifically limited, In order to improve the durability of coating more, it is more preferable to coat a fluororesin by double coating such as double or triple.
The numerical values used in the description of the present embodiment are examples, and are not limited to these numerical values.
In the present embodiment, the fuel addition valve is disposed upstream of the turbocharger, but the fuel addition valve is not essential. For example, some engines inject fuel in a combustion chamber and supply unburned fuel in exhaust gas at the end of the expansion stroke of the engine body or in the exhaust stroke. In the present invention, the operation of the third link (sliding member) is poor even in an engine supplied with unburned fuel from the upstream side of the turbocharger in the exhaust gas path regardless of the presence or absence of the fuel addition valve. Can be prevented.
Further, in the present embodiment, the example in which the pivot shaft of the third link as a sliding member is inserted into the through hole of the bearing side housing has been described. The third link may be inserted through the through-hole, or a through-hole penetrating both the bearing-side housing and the exhaust-side housing may be formed, and the third link inserted through the through-hole. Good. Thus, the third link only needs to be inserted from the outside of at least one of the bearing-side housing and the exhaust-side housing into the accommodation space.
In the present embodiment, the example in which the fluororesin layer is formed on at least a part of the surface of the third link and the surface of the bearing-side housing in contact with or close to the third link has been described. Further, a fluororesin layer may be formed on at least a part of the surface and at least one surface of the bearing-side housing and the exhaust-side housing that are in contact with or close to the third link.

DESCRIPTION OF SYMBOLS 1 Turbocharger 11 Intake side housing 12 Exhaust side housing 13 Bearing side housing 13K Through-hole 15 Accommodating space 21 Intake side impeller 22 Exhaust side impeller (turbine impeller)
23 Turbine shaft 31A Inlet side inlet 31B Inlet side outlet 32A Exhaust side inlet 32B Exhaust side outlet 41 Third link (sliding member)
41A Rotating shaft part 41B Arm 50 Actuator 63 Variable nozzle 70 DPF
71 Fuel addition valve

Claims (2)

In turbocharger with variable nozzle,
In the turbocharger, a turbine impeller and the variable nozzle are accommodated in an accommodation space formed by both the bearing-side housing and the exhaust-side housing, and the turbocharger is inserted from at least one outer side of the two housings to the inside of the accommodation space. A sliding member for driving the variable nozzle,
At least a part of the surface of the sliding member is formed with a fluororesin layer having oil repellency,
Turbocharger. In turbocharger with variable nozzle,
In the turbocharger, a turbine impeller and the variable nozzle are accommodated in an accommodation space formed by both the bearing-side housing and the exhaust-side housing, and the turbocharger is inserted from at least one outer side of the two housings to the inside of the accommodation space. A sliding member for driving the variable nozzle,
A fluororesin layer having oil repellency is formed on at least a part of at least one surface of each of the housings in contact with or close to the sliding member.
Turbocharger.

Images