Bearing rust preventive device for variable capacity turbocharger

Abstract

A variable capacity turbocharger (1) includes a plurality of nozzle vanes (21) which are provided in a nozzle (13) of a turbine (2) in an openable and closable manner, a link mechanism (22) which is linked to the plurality of nozzle vanes, a mechanism chamber (23) which is formed in a turbine housing (4) and accommodates the link mechanism, a bearing (24) which is provided in the turbine housing so as to communicate the mechanism chamber with the outside of the turbine housing, and an operation shaft (25) which is rotatably provided in the bearing and has one end connected to the link mechanism. A bearing rust prevention device of the variable capacity turbocharger includes a gas supply device (50) which is configured to supply pressure gas from the outside of the turbine to contact portions (43), (44) of the bearing and the operation shaft.

Description

Technical Field

[0001] This disclosure relates to a bearing rust prevention device for a variable capacity turbocharger. Background Technology

[0002] Generally, in a variable displacement turbocharger, an operating shaft protruding outward from the turbine is rotated to open and close multiple movable nozzle blades, which are disposed at the turbine nozzles. The operating shaft is rotatably supported by bearings disposed in the turbine housing.

[0003] Prior technology documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2012-47090 Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] However, sometimes rust can seep into the contact area between the bearing and the operating shaft. When this rust intrusion occurs, the friction during the rotation of the operating shaft increases, which may lead to poor rotation.

[0008] Therefore, this disclosure was made in view of the above circumstances, and its object is to provide a bearing anti-rust device for a variable capacity turbocharger that can suppress the infiltration of rust at the contact portion between the bearing and the operating shaft.

[0009] Technical means for solving technical problems

[0010] According to one aspect of this disclosure, a bearing rust prevention device for a variable capacity turbocharger can be provided, comprising:

[0011] Multiple nozzle blades are closable and mounted on the nozzle of the turbine.

[0012] A linkage mechanism, which is connected to the plurality of nozzle blades,

[0013] The mechanism chamber, formed within the turbine housing, houses the linkage mechanism.

[0014] A bearing, which is disposed in the turbine housing, communicates the mechanism chamber with the outside of the turbine housing, and

[0015] An operating shaft, which is rotatably disposed within the bearing, has one end connected to the linkage mechanism;

[0016] The bearing rust prevention device of this variable capacity turbocharger is characterized by the following features:

[0017] It includes a gas supply device configured to supply pressurized gas from outside the turbine to the contact portion between the bearing and the operating shaft.

[0018] Preferably, the operating shaft includes: a first contact surface formed on the mechanism chamber side and in contact with the bearing; a second contact surface formed on the outer side and in contact with the bearing; and a reduced diameter portion formed between the first contact surface and the second contact surface and separated from the bearing.

[0019] The gas supply device supplies pressurized gas into the bearing at the axial position of the reduced diameter section.

[0020] Preferably, the gas supply device supplies pressurized gas at a higher pressure than that inside the mechanism chamber.

[0021] Preferably, the pressurized gas is compressed air generated by the compressor of the turbocharger.

[0022] Preferably, the pressurized gas is compressed air stored in a gas tank.

[0023] Preferably, the gas supply device includes a check valve to prevent backflow in the opposite direction of the pressurized gas supply.

[0024] Preferably, the gas supply device includes: a nozzle disposed on the bearing and supplying pressurized gas into the bearing; a gas supply source; and a piping connecting the nozzle and the gas supply source.

[0025] Invention Effects

[0026] According to this disclosure, it is possible to suppress the penetration of rust at the contact portion between the bearing and the operating shaft. Attached Figure Description

[0027] Figure 1 This is a schematic longitudinal sectional side view of a variable capacity turbocharger.

[0028] Figure 2 yes Figure 1 Enlarged view of the main parts.

[0029] Figure 3 From Figure 1 A rough front view when observing line III-III.

[0030] Figure 4 It is a rough longitudinal sectional side view showing the state before the pressurized gas is supplied.

[0031] Figure 5 It is a rough longitudinal sectional side view showing the state after the pressurized gas is supplied.

[0032] Figure 6 This is a schematic longitudinal sectional side view representing a modified example. Detailed Implementation

[0033] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should also be noted that the present disclosure is not limited to the following embodiments.

[0034] Figure 1 This is a schematic longitudinal sectional side view of the variable capacity turbocharger of this embodiment. Figure 2 yes Figure 1 Enlarged view of the main parts Figure 3 It is to remove the shell cover described later, from Figure 1 A rough front view when observing line III-III. For ease of understanding, Figure 3 Represented using perspective views.

[0035] The internal combustion engine (also called engine) of the turbocharger used in this embodiment is a diesel engine for vehicles. The vehicle is a large vehicle such as a truck. However, there are no particular limitations on the type, form, or purpose of the internal combustion engine; for example, the engine can also be a gasoline engine.

[0036] For simplicity, the directions (front, back, left, right, up, down) are defined as shown in the diagram. However, it should be noted that these directions are only determined for ease of explanation.

[0037] The central axis of the turbine, or turbine shaft, is indicated by the reference numeral C in the attached drawing. Unless otherwise specified, the axial, radial, and circumferential directions with reference to the turbine shaft C will be referred to as the axial, radial, and circumferential directions, respectively.

[0038] Turbocharger 1 includes: a turbine 2 driven by exhaust gas; and a compressor 3 driven by turbine 2 to compress or boost intake air. Turbo 2 includes: a turbine housing 4; and a turbine impeller 5 rotatably disposed within turbine housing 4. Compressor 3 includes: a compressor housing 6; and an impeller 7 rotatably disposed within compressor housing 6. Turbo impeller 5 and impeller 7 are coaxially coupled to each other by turbine shaft 8. Turbo housing 4 and compressor housing 6 are coupled to a central housing 9 located between them. Turbo shaft 8 is supported by a central bearing 10 within central housing 9 so as to be rotatable coaxially with turbine shaft C. Thus, turbine impeller 5, turbine shaft 8, and impeller 7 are integrated, coaxially configured with turbine shaft C, and rotatable about turbine shaft C.

[0039] The turbine housing 4 has: a housing body 11 that houses the turbine impeller 5; and a housing cover 12 that is fixed to the front end of the housing body 11. Inside the housing body 11, there are: a nozzle 13 that supplies exhaust gas from the radial direction outward to the turbine impeller 5; and a turbine vortex chamber 14 that supplies exhaust gas introduced from the turbine inlet (not shown) to the nozzle 13 at a full circumference position.

[0040] Inside the compressor housing 6, there are: a diffuser 15 that guides the compressed air discharged from the impeller 7 outward in a radial direction; and a compressor scroll chamber 16 that guides the compressed air discharged from the diffuser 15 circumferentially toward the compressor outlet (not shown).

[0041] In addition, the turbocharger 1 includes: a plurality of nozzle blades 21 which are openably and closably disposed on nozzles 13; a linkage mechanism 22 which is connected to the plurality of nozzle blades 21; a mechanism chamber 23 which is formed within the turbine housing 4 and houses the linkage mechanism 22; a bearing 24 which is disposed within the turbine housing 4 to communicate the mechanism chamber 23 with the outside; and an operating shaft 25 which is rotatably disposed within the bearing 24 and has one end (front end) connected to the linkage mechanism 22.

[0042] The bearing 24 is formed as a sliding bearing. The bearing 24 is formed of a metal tube, such as a steel tube, having a predetermined length and a certain inner and outer diameter, and is configured to extend in the front-to-back direction parallel to the turbine shaft C. The bearing 24 passes through the housing body 11 and is fixed to the housing body 11, with its front end (inner end) located inside the mechanism chamber 23 and its rear end (outer end) located outside the turbine housing 4.

[0043] An operating shaft 25 is coaxially and rotatably disposed within the bearing 24. The operating shaft 25 is rotatable about its central axis C1. The front and rear ends of the operating shaft 25 protrude from the bearing 24. A drive plate 26 of a linkage mechanism 22 is fixed to the front end of the operating shaft 25. An operating lever 27 is fixed to the rear end of the operating shaft 25. The operating lever 27 is connected to a driver (not shown) via a link 28 and is driven to rotate about the central axis C1 by the driver. The driving force of the driver is ultimately transmitted to the nozzle blade 21 via the linkage mechanism 22. The driver is, for example, formed by a servo motor.

[0044] The operating shaft 25 includes: an inner contact surface 29 serving as a first contact surface; an outer contact surface 30 serving as a second contact surface; and a reduced-diameter portion 31 formed between the inner contact surface 29 and the outer contact surface 30. The inner contact surface 29 is formed on the mechanism chamber 23 side in the direction of the central shaft C1 and contacts the inner circumferential surface of the bearing 24. The outer contact surface 30 is formed on the outer side in the direction of the central shaft C1 and contacts the inner circumferential surface of the bearing 24. The reduced-diameter portion 31 is formed to have a smaller diameter than both the inner contact surface 29 and the outer contact surface 30 and is separated from the inner circumferential surface of the bearing 24. Thus, a gap 32 is formed between the bearing 24 and the reduced-diameter portion 31.

[0045] In the linkage mechanism 22, the drive plate 26 rotates integrally with the operating shaft 25. The drive plate 26 is formed in the shape of two downward-pointing prongs, with a quadrilateral connector plate 33 slidably clamped in its prong portion. The rear end of a pin 34 is rotatably mounted on the connector plate 33. The front end of the pin 34 is rotatably mounted to the input arm 36 of the coordinating ring 35. The coordinating ring 35 is formed in the shape of a ring plate surrounding the turbine shaft C and is rotatably supported by the housing body 11 around the turbine shaft C.

[0046] The coordinating ring 35 is connected to a plurality of nozzle blades 21 (15 in this embodiment) as described below, the plurality of nozzle blades 21 being arranged at equal intervals in the circumferential direction. First, each nozzle blade 21 integrally has a blade shaft 37 serving as its axis of rotation. The blade shaft 37 is slidably and rotatably inserted through a bearing hole 38 in the housing body 11 and protrudes into the mechanism chamber 23. A blade arm 39 is fixed to the front end of the protruding blade shaft 37.

[0047] The blade arm 39 is formed into a fork shape with two prongs pointing outward in the radial direction. A generally quadrilateral connector plate 40 is slidably clamped in its fork portion. The rear end of a pin 41 is rotatably mounted on the connector plate 40. The front end of the pin 41 is rotatably mounted on the coordinating ring 35.

[0048] Therefore, the rotation of the operating shaft 25 is transmitted to the nozzle blade 21 through the linkage mechanism 22, and the nozzle blade 21 is rotated. Figure 3 As shown, when the operating shaft 25 rotates along the A1 direction, the coordinating ring 35 rotates along the B1 direction, and the nozzle blade 21 rotates along the V1 direction, i.e., the valve closing direction. Conversely, when the operating shaft 25 rotates along the A2 direction, the coordinating ring 35 rotates along the B2 direction, and the nozzle blade 21 rotates along the V2 direction, i.e., the valve opening direction.

[0049] exist Figure 3 In the figure, reference numeral 42 indicates multiple internal threaded holes used to bolt the housing cover 12 to the housing body 11. Reference numeral 43 indicates an elongated hole provided in the coordinating ring 35 to avoid interference from the blade shaft 37.

[0050] When the housing cover 12 is installed on the housing body 11, a sealed mechanism chamber 23 is formed between them. The linkage mechanism 22 is disposed within this mechanism chamber 23.

[0051] In such a turbocharger 1, rust can seep into the contact area between the bearing 24 and the operating shaft 25, increasing friction during the rotation of the operating shaft 25 and potentially causing poor rotation.

[0052] Therefore, in this embodiment, a bearing rust prevention device is provided to suppress the penetration of such rust. The bearing rust prevention device includes a gas supply device 50, which is configured to supply pressurized gas from outside the turbine 2 to the contact portion between the bearing 24 and the operating shaft 25.

[0053] The gas supply device 50 includes: a nozzle 51 disposed on a bearing 24 and supplying pressurized gas into the bearing 24; a compressor 3 serving as a gas supply source; and a piping 52 connecting the nozzle 51 and the compressor 3. In this embodiment, the compressor 3 is used as the gas supply source, and the compressed air generated by the compressor 3 is used as the pressurized gas.

[0054] Nozzle 51 is formed by a pipe fitting (e.g., a threaded fitting) that passes through the inside and outside of bearing 24 and is fixed to bearing 24. Nozzle 51 is positioned perpendicular to the central axis C1 where the reduced diameter portion 31 is located and is located outside the turbine housing 4. Nozzle 51 discharges high-pressure compressed air into the gap 32 between bearing 24 and reduced diameter portion 31. Thus, gas supply device 50 supplies pressurized gas to bearing 24 at the axial position of reduced diameter portion 31.

[0055] Piping 52 includes: an outlet pipe 53, which is installed in the compressor housing 6; and a connecting pipe 54, which connects the nozzle 51 and the outlet pipe 53. Like the nozzle 51, the outlet pipe 53 is formed by a pipe fitting (e.g., a threaded fitting) that penetrates both the inside and outside of the compressor housing 6 and is fixed to the compressor housing 6. The outlet pipe 53 communicates with the compressor scroll chamber 16 downstream of the impeller 7, drawing compressed air from the compressor scroll chamber 16.

[0056] The connecting tube 54 is formed of a rubber hose or tube. However, the material of the connecting tube 54 is arbitrary and can also be metal or resin. The upstream end of the connecting tube 54 is connected to the outlet tube 53, and the downstream end is connected to the nozzle 51.

[0057] Furthermore, the gas supply device 50 includes a check valve 55 to prevent backflow in the opposite direction to the pressurized gas supply. In this embodiment, the check valve 55 is installed on the piping 52 and midway through the connecting pipe 54. However, its location is arbitrary; for example, it can be integrally assembled with the nozzle 51 or the outlet pipe 53. The check valve 55 only allows flow from the compressor 3 side to the bearing 24 side and prohibits reverse flow.

[0058] Next, as mentioned earlier, sometimes rust can seep into the contact area between the bearing 24 and the operating shaft 25, resulting in what is known as corrosion. This contact area refers to the contact area between the inner contact surface 29 and the bearing 24 (referred to as the inner contact area) 43, and the contact area between the outer contact surface 30 and the bearing 24 (referred to as the outer contact area) 44.

[0059] Rust can be caused by a variety of factors, but one of the most significant is the rust that forms within the mechanism chamber 23 of the turbine housing 4. Exhaust gas passing through the nozzle 13 passes through a tiny gap between the blade shaft 37 and the bearing bore 38, and although only a small amount, it leaks into the mechanism chamber 23. This exhaust gas causes rust to form within the mechanism chamber 23.

[0060] In particular, when the engine is operating under low load and at low temperatures, and in environments with low external atmospheric temperatures, the exhaust temperature is low. Therefore, the water vapor contained in the exhaust may condense below the dew point, producing condensate. This condensate contains dissolved sulfuric acid, nitric acid, and organic acids generated during fuel combustion, making it a highly corrosive acidic solution. Consequently, when condensate adheres to the interior of the engine compartment 23, it can easily lead to rust formation.

[0061] During engine operation, exhaust gas leaks into the mechanism chamber 23, causing the pressure inside the chamber to be higher than the external atmospheric pressure. This creates a flow of exhaust gas leaking from the mechanism chamber 23 through the bearing 24 and the operating shaft 25 to the outside. As this flow occurs, rust within the mechanism chamber 23 also moves.

[0062] Some of the rust generated inside the mechanism chamber 23 peels off, moves within the chamber, passes through the gap between the drive plate 26 and the front end face of the bearing 24, and seeps into the inner contact portion 43. Then, it moves to the outer side in the direction of the central shaft C1, and passes through the gap 32 and the outer contact portion 44 in sequence, finally being discharged to the outside. Additionally, sometimes other foreign matter may also seep in and move along with the rust.

[0063] On the other hand, another reason for rust formation on the outer surface of the turbocharger 1, particularly near the outer contact portion 44, can be cited. In winter, salt (rock salt or de-icing agents such as calcium chloride) is sometimes spread on the road surface as an antifreeze. This salt mixes with rainwater or condensation adhering to the outer surface of the turbocharger 1, forming a highly corrosive brine. This brine causes rust to form on the outer surface of the turbocharger 1.

[0064] Part of the rust will peel off, approaching the outer contact portion 44. Then, after passing through the gap between the operating lever 27 and the rear end face of the bearing 24, the rust will penetrate into the outer contact portion 44. Then, it may sometimes move further inward toward the central axis C1, successively penetrating the gap 32 and the inner contact portion 43.

[0065] During the movement of the rust described above, the rust will stop and accumulate at the inner contact portion 43 and the outer contact portion 44. Sometimes, the rust will be discharged from the contact portions 43 and 44 by the rotation of the operating shaft 25, but when the accumulation rate is greater than the discharge rate, the amount of accumulation will gradually increase.

[0066] When rust adheres to and accumulates at the contact points 43 and 44, the friction during the rotation of the operating shaft 25 will increase. In the worst case, the operating shaft 25 will be fixed to the bearing 24 and will not move. Therefore, the following may occur: the operating shaft 25 may not rotate properly, and the rotation of the operating shaft 25, and even the opening and closing of the nozzle blades 21, will not proceed normally.

[0067] Therefore, in this embodiment, in order to suppress the adhesion of rust to the contact portions 43 and 44, compressed air is supplied to the bearing 24 via the gas supply device 50. (Refer to...) Figure 4 and Figure 5 This section explains the actions taken at this time.

[0068] Figure 4 This indicates the state of rust R adhesion before compressed air supply. Rust R adheres not only to the inner contact portion 43 and the outer contact portion 44, but also to various other areas.

[0069] In this state, when the pressure inside the compressor scroll chamber 16 becomes higher than the pressure inside the mechanism chamber 23, the check valve 55 will open, such as... Figure 5 As indicated by the arrow, compressed air in the compressor scroll chamber 16 passes through the outlet pipe 53 and the connecting pipe 54 in sequence, and is supplied from the nozzle 51 into the gap 32.

[0070] The compressed air is divided into two streams: airflow F1, which flows towards the inside of the turbine housing 4, and airflow F2, which flows towards the outside. The airflow F1 flowing towards the inside pushes out the rust R adhering to the inner contact portion 43 and discharges it into the mechanism chamber 23. The airflow F2 flowing towards the outside pushes out the rust R adhering to the outer contact portion 44 and discharges it to the outside. In this way, the rust adhering to the inner contact portion 43 and the outer contact portion 44 can be removed. At the same time, the rust adhering to the gap 32 can also be removed.

[0071] Furthermore, when the pressure inside the compressor scroll chamber 16 is higher than the pressure inside the mechanism chamber 23, compressed air is always supplied, thus suppressing the infiltration of new rust R into the inner contact portion 43 and the outer contact portion 44 through the aforementioned airflows F1 and F2. Therefore, the adhesion of rust R can be prevented.

[0072] Thus, the gas supply device 50 supplies pressurized gas at a higher pressure than that inside the mechanism chamber 23.

[0073] On the other hand, when the pressure inside the compressor scroll chamber 16 is lower than the pressure inside the mechanism chamber 23, the check valve 55 will be closed. Therefore, it is possible to prevent the backflow of exhaust gas from the mechanism chamber 23 into the compressor scroll chamber 16.

[0074] Thus, according to this embodiment, because the gas supply device 50 is provided, the infiltration of rust R at the contact portions 43 and 44 between the bearing 24 and the operating shaft 25 can be suppressed.

[0075] Furthermore, according to this embodiment, even when two contact portions such as the inner contact portion 43 and the outer contact portion 44 are provided, the infiltration of rust into the two contact portions can be effectively suppressed.

[0076] Furthermore, according to this embodiment, since compressed air with a higher pressure than that inside the mechanism chamber 23 is supplied, rust that has penetrated into the inner contact portion 43 can be reliably discharged into the mechanism chamber 23.

[0077] Furthermore, according to this embodiment, since the compressed air generated by the compressor 3 of the turbocharger 1 is used as a pressurized gas, a separate gas supply source is not required, thus simplifying the configuration. Additionally, the distance from the gas supply source to the gas supply position (nozzle 51) can be shortened, reducing pressure loss.

[0078] Furthermore, according to this embodiment, since pressurized gas is supplied from outside the turbine 2, it is advantageous for suppressing rust adhesion at the contact portion. That is, when pressurized gas from inside the turbine 2, i.e., exhaust gas, is supplied to the contact portion, as described above, the contact portion will rust more easily due to the acidic water condensed from the exhaust gas. However, in this embodiment, since pressurized gas is supplied from outside the turbine 2, such rusting can be avoided, and the rust prevention effect can be improved.

[0079] The embodiments of this disclosure have been described in detail above, but various embodiments and variations of this disclosure are also possible.

[0080] (1) For example, such as Figure 6 As shown, the air tank 61, which is separately provided with the turbocharger 1, can also be used as a source of pressurized gas, and the compressed air stored in the air tank 61 can be used as pressurized gas. In the case of the vehicle of this embodiment, such an air tank 61 is provided for the operation of the brakes, etc., so by utilizing it, it is not necessary to provide a separate gas supply source.

[0081] (2) As a pressurized gas, gases other than air can also be used, such as nitrogen, argon and other non-flammable gases.

[0082] (3) There may also be one contact portion between the bearing and the operating shaft. In this case, it is preferable to supply pressurized gas directly to the contact portion.

[0083] (4) Alternatively, a solenoid valve can be installed instead of a check valve, and controlled by a control unit. In this case, the bearing rust prevention device includes: a gas supply device comprising a solenoid valve; a control unit; a first pressure sensor that detects the pressure inside the mechanism chamber; and a second pressure sensor that detects the gas pressure of the gas supply source. The control unit opens the solenoid valve when the gas pressure detected by the second pressure sensor is higher than the pressure inside the mechanism chamber detected by the first pressure sensor, and closes the solenoid valve otherwise. For example, an electronic control unit (ECU) mounted in the vehicle for engine control can be used.

[0084] The embodiments described herein are not limited to those described above. All modifications, applications, and equivalents of the ideas contained in this disclosure as defined by the scope of protection are included in this disclosure. Therefore, this disclosure should not be interpreted restrictively and can be applied to any other technology falling within the scope of this disclosure.

[0085] This application is based on Japanese Patent Application No. 2020-121558, filed on July 15, 2020, the contents of which are incorporated herein by reference.

[0086] Explanation of reference numerals in the attached figures

[0087] 1. Turbocharger

[0088] 2 turbos

[0089] 3. Compressor

[0090] 4. Turbine housing

[0091] 13 Nozzles

[0092] 21 Nozzle blades

[0093] 22-linkage mechanism

[0094] 23 Institutional Office

[0095] 24 bearings

[0096] 25 operating axes

[0097] 29 Inner contact surface

[0098] 30 Outer contact surface

[0099] 31. Reduction section

[0100] 43 Inner contact area

[0101] 44 Outer contact area

[0102] 50 Gas supply device

[0103] 51 Nozzle

[0104] 52 Piping

[0105] 55 Check valve

[0106] 61 gas cylinders

Claims

1. A bearing rust prevention device for a variable displacement type turbocharger, comprising: a plurality of nozzle vanes provided in a nozzle of a turbine in an openable and closable manner; a link mechanism coupled to the plurality of nozzle vanes; a mechanism chamber formed in a turbine housing and accommodating the link mechanism; a bearing provided in the turbine housing to communicate the mechanism chamber with an outside of the turbine housing; and an operation shaft provided in the bearing in a rotatable manner, having one end coupled to the link mechanism, the bearing rust prevention device for the variable displacement type turbocharger characterized by comprising a gas supply device configured to supply a pressure gas to a contact portion of the bearing and the operation shaft from the outside of the turbine.

2. The bearing rust prevention device for the variable displacement type turbocharger according to claim 1, wherein the operation shaft includes a first contact surface formed on the mechanism chamber side and contacting the bearing, a second contact surface formed on the outside side and contacting the bearing, and a reduced diameter portion formed between the first contact surface and the second contact surface and separated from the bearing, and the gas supply device supplies the pressure gas into the bearing at an axial position of the reduced diameter portion.

3. The bearing rust prevention device for the variable displacement type turbocharger according to claim 1 or 2, wherein the gas supply device supplies the pressure gas having a higher pressure than a pressure in the mechanism chamber.

4. The bearing rust prevention device for the variable displacement type turbocharger according to claim 1 or 2, wherein the pressure gas is compressed air generated by a compressor of the turbocharger.

5. The bearing rust prevention device for the variable displacement type turbocharger according to claim 1 or 2, wherein the pressure gas is compressed air stored in a gas tank.

6. The bearing rust prevention device for the variable displacement type turbocharger according to claim 1 or 2, wherein the gas supply device includes a check valve for preventing a backflow in a direction opposite to a pressure gas supply direction.

7. The bearing rust prevention device for the variable displacement type turbocharger according to claim 1 or 2, wherein the gas supply device includes the nozzle provided in the bearing to supply the pressure gas into the bearing, a gas supply source, and a pipe connecting the nozzle and the gas supply source. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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