JP2009127437A - Supercharger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a supercharger without impairing performance by oil leaking-out, by preventing the leaking-out of oil into a compressor with a simple constitution, even if lubricating or cooling oil is supplied under high pressure. <P>SOLUTION: In this supercharger 1, a turbine housing 7 and a compressor housing 10 are arranged on both sides of a bearing housing 8; a driving shaft 4 is inserted inside these; a turbine impeller and a compressor impeller are arranged on the driving shaft 4; a bearing for supporting the driving shaft 4 is arranged between the bearing housing 8 and the driving shaft 5; and a flow passage of the cooling or lubricating oil O is formed in the bearing housing 10. At least one of the bearing is formed of a thrust bearing 30, and an oil drain passage 39 for introducing surplus oil O supplied by the flow passage in the direction separating from a sliding contact part 33a, is arranged in the vicinity of the sliding contact part 33a between the thrust bearing 30 and the driving shaft 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a supercharger that prevents oil supplied to a bearing housing positioned between a turbine housing and a compressor housing from leaking into the compressor housing.

  As is well known, in a turbocharger, a turbine and a compressor are arranged on the same rotation shaft, the turbine impeller in the turbine and the compressor impeller in the compressor are connected by a drive shaft, and the turbine impeller is rotated by exhaust gas or the like. When moved, the compressor impeller is rotated via the drive shaft, and air or the like is compressed. Further, in a bearing housing that is disposed between the turbine and the compressor and accommodates a drive shaft and the like, oil is supplied to smoothly rotate the drive shaft and a bearing that supports the drive shaft and cool them. However, various measures are taken so that the oil does not leak from the periphery of the drive shaft into the compressor and the performance of the supercharger is deteriorated.

  For example, in the seal structure described in Patent Document 1 below, a seal ring is provided in a drive shaft insertion portion of a sealing blade that is positioned between a bearing housing and a compressor housing and defines both, and the seal ring and the drive shaft The oil is sealed by the groove portion formed in the inner portion, and the clearance between the seal ring and the groove portion can be adjusted. That is, a screw part is formed on the drive shaft and a nut having an end surface that forms a part of the groove part is screwed, and the nut is screwed to adjust the clearance to obtain a high sealing performance. To prevent leakage.

Moreover, the seal structure described in the following Patent Document 2 describes a supercharger that employs a labyrinth structure for a sealing plate that partitions a compressor housing and a bearing housing. That is, a labyrinth brave having a hollow disk shape including a first plate-like body located on the compressor side and a second plate-like body located on the turbine side and having a gap formed therein by the two plate-like bodies. It is provided between the compressor housing and the bearing housing. With this configuration, the labyrinth blade is curved in the axial direction by utilizing the atmospheric temperature difference in each plate, and the clearance between the outer peripheral surface of the shaft and the circular hole portion of the labyrinth blade is adjusted to prevent oil leakage. ing.
Patent Documents 3 to 5 listed below are techniques for preventing oil leakage as disclosed in Patent Documents 1 and 2 below.
JP 2004-285887 A Japanese Patent Laid-Open No. 7-119477 JP 2005-30382 A JP 2004-68820 A JP 2006-837779 A

However, when the seal structure in Patent Document 1 is applied to a turbocharger in which a part of a thrust bearing near the compressor forms an oil flow path and oil is supplied at a high pressure, the seal ring and the groove Even if the clearance is adjusted moderately, because the oil supply pressure is high, a large amount of oil leaks from the sliding contact portion of the shaft (or the oil cutter) and the bearing, and the leaked oil may be sealed by the sealing mechanism. There was a problem that I could not.
In addition, since the structure of the seal structure in Patent Document 2 is complicated, it is difficult to employ it in a small turbocharger that has space constraints. In addition, the manufacturing cost and manufacturing process are disadvantageous.

  The present invention has been made in view of such circumstances, and its purpose is to prevent oil from leaking into the compressor with a simple configuration even when lubricating or cooling oil is supplied at high pressure. And providing a turbocharger whose performance is not impaired by oil leakage.

In order to achieve the above object, the present invention proposes the following means.
According to the first aspect of the present invention, a turbine housing and a compressor housing are provided on both sides of a bearing housing, and a drive shaft is inserted into each of the housings. An impeller is provided and a compressor impeller is provided on the drive shaft in the compressor housing, and a bearing is provided between the bearing housing and the drive shaft to support the drive shaft, and cooling or lubrication is provided in the bearing housing. In the turbocharger in which a flow path for circulating oil is formed, at least one of the bearings is a thrust bearing, and the front portion of the bearing is located near the sliding contact portion between the thrust bearing and the drive shaft. And it is characterized in that formed by providing an oil discharge passage for guiding in a direction away excess oil supplied from the sliding theory section by the channel.

The invention according to claim 2 is characterized in that, in the supercharger according to claim 1, the oil discharge hole is provided in an inner surface of the thrust bearing.
According to a third aspect of the present invention, in the turbocharger according to the second aspect, a thrust collar that is in sliding contact with the inner surface of the thrust bearing is fixed to the drive shaft, and one of the flow paths is formed on the inner surface of the thrust bearing. And an oil storage part that temporarily stores oil supplied between the inner surface and the thrust collar, and the oil discharge passage communicates the inside of the oil storage part with the outside of the thrust bearing. It is characterized by being provided.

  According to a fourth aspect of the present invention, in the turbocharger according to the third aspect, an oil cooling chamber for cooling is provided in an upper portion of the bearing housing on the turbine housing side, and the thrust bearing is provided by the oil cooling chamber. A part of the flow path corresponding to the downstream side of the flow path formed by the inner surface of the oil discharge path is formed, and the flow path cross section of the oil discharge path ensures the predetermined flow rate of the oil flowing to the oil cooling chamber. A part of the oil is discharged to the outside, and the oil pressure in the vicinity of the sliding contact portion is set so as to prevent the oil from moving to the sliding contact portion side.

  According to the present invention, a turbine housing and a compressor housing are provided with a bearing housing interposed therebetween, and a drive shaft provided with a turbine impeller and a compressor impeller is inserted into these, and the bearing housing and the drive shaft are inserted into the drive shaft. In the turbocharger in which a bearing for supporting the drive shaft is provided between them and an oil passage for cooling or lubrication is formed in the bearing housing, at least one of the bearings is a thrust bearing, and the thrust bearing In the vicinity of the slidable contact portion between the drive shaft and the drive shaft, an oil discharge passage is provided in this portion to guide the excess oil supplied by the flow path in a direction away from the sliding portion. Even if there are many Without reaching the sliding contact portion between the bets bearing and the drive shaft, can be a large amount of oil from the sliding contact portion is prevented from leaking. Thereby, it is possible to prevent oil from leaking into the compressor.

  In the invention described in claim 2, since the oil discharge passage is provided on the inner surface of the thrust bearing, machining is performed on the thrust bearing, which is a small part, and the internal structure of the compressor can be achieved with a simple configuration and machining. Oil leakage to the can be prevented. Also, the production cost can be reduced.

  In the invention described in claim 3, a thrust collar is fixed so that the drive shaft is in sliding contact with the inner surface of the thrust bearing, and a part of the flow path is formed on the inner surface of the thrust bearing so that the inner surface and the thrust collar An oil reservoir that temporarily stores the oil supplied therebetween is provided, and an oil discharge path is provided so as to communicate the inside of the oil reservoir and the outside of the thrust bearing. The excess oil can be discharged to the outside of the thrust bearing, the oil capacity of the oil reservoir can be optimally secured, and oil leakage can be effectively prevented.

In the invention described in claim 4, the flow passage cross section of the oil discharge passage discharges a part of the oil to the outside while ensuring a predetermined flow rate of the oil flowing to the oil cooling chamber. Since the oil pressure in the vicinity of the part is set to prevent the oil from moving to the sliding contact part side, the oil necessary and sufficient for cooling can be flown into the oil cooling chamber and oil leakage is prevented. be able to. This makes it possible to achieve both the cooling performance and the sealing performance that have been difficult to achieve in the past.
Further, oil leakage can be prevented without changing the flow of the oil flow path and without disturbing the circulation of the oil.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view showing an overall configuration of a supercharger 1 according to an embodiment of the present invention, and FIG. 2 is a partially enlarged view of the supercharger 1. The supercharger 1 is applied to an internal combustion engine of a vehicle.

  As shown in FIG. 1, the supercharger 1 is schematically composed of a turbine impeller 2, a compressor impeller 3, a drive shaft 4 to which the turbine impeller 2 and the compressor impeller 3 are fixed, and a housing 5 that houses them. It is configured.

  The turbine impeller 2 and the drive shaft 4 are integrated by welding, and the compressor impeller 3 and the drive shaft 4 are coupled via a nut 6. The housing 5 includes a turbine housing 7 in which the turbine impeller 2 is accommodated, a bearing housing 8 in which a bearing of the drive shaft 4 and the like are accommodated, a seal plate 9 that partitions the bearing housing 8 and the compressor housing 10, and a compressor The compressor housing 10 in which the impeller 3 is accommodated is connected in order.

  In the supercharger 1, oil O is supplied to the inside of the bearing housing 8 in order to smoothly slide the drive shaft 4 and the bearings that support the drive shaft 4 and to cool the drive shaft 4 and the housing 5. . Therefore, an oil supply port 11 for supplying oil O from the outside is provided in the upper portion of the bearing housing 8, and an oil discharge port 12 for discharging the oil O from the inside is provided in the lower portion of the bearing housing 8. . In the figure, the dashed arrow indicates the flow of the oil O.

  Inside the bearing housing 8, there is a shaft support portion 13 through which the drive shaft 4 is inserted to form a large diameter on the compressor side, an oil discharge chamber 14 surrounding the shaft support portion 13, and the shaft support portion 13. A first oil supply hole 15 that is perforated along the shaft support portion 13 in the upper part and communicates perpendicularly to the oil supply port 11 is provided.

  The shaft support portion 13 is provided with a floating metal (bearing) 16 on the turbine side and a floating metal 17 on the compressor side. The floating metals 16 and 17 are cylindrical members having a plurality of through holes on the peripheral surface, and the drive shaft 4 is supported in the radial direction via these so as to be rotatable. That is, when oil O is supplied to the floating metals 16 and 17 from the second oil supply hole 22 and the third oil supply hole 23 which will be described later, between the floating metals 16 and 17 and the shaft support portion 13 and between the drive shaft 4 and the floating metal 16. , 17, and the oil O spreads between them, and the drive shaft 4 can be smoothly rotated even at a high rotational speed. The floating metals 16 and 17 cannot be moved in the axial direction by a retaining ring 16a or a bearing spacer 17a provided on the shaft support portion 13.

The oil discharge chamber 14 includes a lower oil discharge space 18 that communicates with the oil discharge port 12, an upper cooling space (oil cooling chamber) 19 that surrounds the upper portion of the shaft support 13 on the turbine side, the drive shaft 4, and the turbine impeller 2. A turbine-side seal space 21 surrounding the slinger 20 provided on the outer periphery of the connecting portion is provided.
The first oil supply hole 15 includes a second oil supply hole 22 and a third oil supply hole 23 that supply oil O from the first oil supply hole 15 to the floating metals 16 and 17, and the oil O supplied to the floating metals 16 and 17 at the bottom. An oil drain hole 24 for discharging to the oil drain space 18 is provided.

  3 is a sectional view taken along line III-III in FIG. 2, and FIG. 4 is a sectional view taken along line IV-IV in FIG. In addition to the above-described components, the bearing housing 8 is provided with oil return holes 25 a and 25 b that communicate obliquely from the vicinity of the center of the thrust bearing mounting surface 8 a toward the upper cooling space 19. The oil return holes 25a and 25b are opened at the same distance from the rotation center axis of the drive shaft 4 and at the same position in the vertical direction.

  Referring back to FIGS. 1 and 2, the load in the thrust direction of the drive shaft 4 is the turbine side thrust bearing (hereinafter referred to as “T side thrust bearing”) 26, the thrust collar 27, and the compressor side thrust bearing (hereinafter referred to as C side). This is called a thrust bearing.

The T-side thrust bearing 26 is attached to the shaft support portion 13 from the compressor side, and is disposed so as to contact the compressor-side end surface of the floating metal 17 and the flat surface 8 b of the bearing housing 8.
The thrust collar 27 fixed to the drive shaft 4 has a C-side thrust bearing 30 and a C-side thrust bearing 30 which are fixed to the thrust bearing mounting surface 8a by a screw (not shown). It is arranged so as to be sandwiched between.
That is, the thrust collar 27 transmits the axial load generated on the drive shaft 4 to the T-side thrust bearing 26 and the C-side thrust bearing 30, and the air pressure applied to the drive shaft 4 by the T-side thrust bearing 26 and the C-side thrust bearing 30. It is configured to support axial force due to gas pressure and vibration.

  5A and 5B are views showing the thrust bearing 30. FIG. 5A is a top view, FIG. 5B is a front view, and FIG. 5C is a cross-sectional view taken along line cc in FIG. FIG. 6 is a cross-sectional view taken along line VI-VI in FIG.

As shown in FIG. 5A, the thrust bearing 30 is a disk-shaped member, and an insertion hole 33 into which the drive shaft 4 is inserted through an oil drill 42 described later in the vicinity of the center of the inner surface 31 and the outer surface 32. Has penetrated. That is, the sliding surface of the insertion hole 33 and the oil drill 42 becomes the sliding contact portion 33 a of the thrust bearing 30 and the drive shaft 4.
Further, the inner surface 31 is positioned on the outer peripheral side and is in contact with the thrust bearing mounting surface 8a of the bearing housing 8 and is in contact with the thrust collar 27 which is positioned around the insertion hole 33 and slides therewith. Four pads 31b are provided.

  A first oil groove 34 is formed in a substantially semicircular arc shape along the outer periphery of the thrust bearing 30 at the upper portion of the abutting surface 31a. The first oil groove 34 is an oval groove deeper than the first oil groove 34. Five pocket grooves 35 (35a, 35b) are provided along the first oil groove 34 at substantially equal intervals. Of the five pocket grooves 35, the pocket grooves 35b other than the pocket groove 35a provided at a position corresponding to the first oil supply hole 15 (see FIG. 3) above the thrust bearing 30 are shown in FIG. As shown in FIG. 6 and FIG. 6, an oil supply port 36 communicating with the pad 31b is provided.

  Further, as shown in FIG. 5 (a), an oil storage portion 37 formed in a fan shape and in a taper shape in the thickness direction as shown in FIG. 6 is provided below the contact surface 31a. . Further, an oil discharge path 39 communicating with the oil discharge chamber 15 (lower oil discharge space 18) is provided at the lower portion of the oil storage portion 37. The oil discharge path 39 is configured so that the pressure and flow rate in the flow path of the oil O formed by the inner surface 31 of the C-side thrust bearing 30, the thrust collar 27, and the like are optimized based on the supply pressure and flow rate of the oil O. The amount of oil O necessary and sufficient for cooling flows from the flow path to the downstream side (upper cooling space 19).

  The pad 31b has a fan shape that contacts and slides on the thrust collar 27, and the oil supply port 36 is opened on the sliding surface of the pad 31b. Four pads 31b are provided point-symmetrically with respect to the center of the thrust bearing 30, and grooves formed in two stages are provided between the pads 31b.

  A second oil groove 38 is formed in a substantially arc shape between the contact surface 31a and the pad 31b, and communicates with the four grooves between the oil reservoir 37 and each pad 31b. Further, the second oil groove 38 is provided with two oil passage grooves 38a and 38b whose areas are increased at positions corresponding to the two oil return holes 25a and 25b in the bearing housing 8.

  As shown in FIG. 5A, the C-side thrust bearing 30 abuts on the thrust bearing mounting surface 8a to form a bearing flow path r. That is, the bearing channel r is formed in the pocket groove 35b after the oil O supplied from the first oil supply hole 15 to the pocket groove 35a of the thrust bearing 30 reaches the pocket groove 35b via the first oil groove 34. The oil flows into the formed oil supply port 36 and flows out from the oil supply port 36 of the pad 31b. The second oil groove 38 and the second oil groove 38 are formed mainly through two grooves formed between the pads 31b. These are a series of flow paths that flow through an annular flow path r1 formed by the oil reservoir 37.

Further, the first flow path R1 and the second flow path R2 are formed in the bearing housing 8 by the configuration described above.
As shown in FIG. 2, the first flow path R <b> 1 is formed in the shaft support portion 13 after the oil O supplied from the oil supply port 11 to the first oil supply hole 15 passes through the second oil supply hole 22 and the third oil supply hole 23. Into the lower oil discharge space 18 through the oil discharge hole 24 and discharged from the oil discharge port 12.
In the second flow path R2, the oil O flowing in the compressor direction of the first oil supply hole 15 flows into the oil return hole 25 after passing through the bearing flow path r formed by the thrust bearing 30 and the bearing housing 8, and is cooled by the upper part. After reaching the use space 19, it flows down to the lower oil discharge space 18 and is discharged from the oil discharge port 12.

Returning to FIG. 1, reference numeral 40 is a seal portion formed on the turbine side of the bearing housing 8, and 41 is a seal portion formed on the compressor side of the bearing housing 8.
The seal portion 41 is fixed so that a cylindrical oil cutter 42 having a flange portion comes into contact with the compressor impeller 3, and a seal groove formed in the oil cutter 42 and a seal ring 43 fixed to the seal plate Oil O does not leak into the compressor.

Next, the operation of the supercharger 1 having the above-described configuration will be described. When the turbine impeller 2 is rotated by the relatively high temperature exhaust gas of the internal combustion engine, the rotational force is transmitted to the compressor impeller 3 via the drive shaft 4. . And the air compressed with rotation of the compressor impeller 3 is supplied to an internal combustion engine. The rotation speed of the drive shaft 4 is, for example, tens of thousands to several hundred thousand rpm.

As the turbine impeller 2 rotates, oil O is supplied into the bearing housing 8 by a pressure device (not shown) provided in the vehicle.
First, as shown in FIG. 1, the oil O reaches the first oil supply hole 15 after flowing into the oil supply port 11, and the flow is divided into the first flow path R1 and the second flow path R2. As described above, the oil O that has flowed into the first flow path R1 flows into the shaft support portion 13 through the second oil supply hole 22 and the third oil supply hole 23, and then flows into the lower oil discharge space 18 through the oil discharge hole 24. And is discharged from the oil discharge port 12.

  On the other hand, the oil O that has flowed into the second flow path R2 reaches the bearing flow path r from the first oil supply hole 15 as shown in FIG. That is, the oil O that has flowed into the pocket groove 35a flows from the pocket groove 35a to the first oil groove 34 and reaches each pocket groove 35b. The oil O reaches the pad 31b through the oil supply port 36 formed in each pocket groove 35b, and lubricates the pad 31b and the thrust collar 27. Thereafter, the oil O flowing out between the pad 31b and the thrust collar 27 mainly reaches the two-stage groove formed in the pad 31b and flows out into the annular flow path r1. The oil O also reaches between the T-side thrust bearing 26 and the thrust collar 27 via the periphery of the thrust collar 27.

At this time, a part of the oil O that has flowed out into the second oil groove 38 reaches the sliding contact portion 33a, but the supply pressure of the oil O is high, and even if the flow rate of the oil O is large, surplus The oil O is discharged from the oil discharge passage 39 to the lower oil discharge space 18. That is, excess oil O is guided in the direction in which the sliding contact portion 33a is separated from the oil discharge passage 39, so that a large amount of oil O does not leak from the sliding contact portion 33a, and a small amount of oil O reaches the seal portion 41. It becomes.
On the other hand, even if surplus oil O is discharged from the oil discharge passage 39, the flow rate of the oil O on the downstream side of the bearing flow passage r does not become insufficient, and the upper cooling space 19 is cooled. Thus, a necessary and sufficient amount of oil O flows in, and the bearing housing 8 and the like are sufficiently cooled.

  In this way, the supercharger 1 operates continuously and stably without the oil O leaking into the compressor housing 10, and the compressed air is sequentially supplied to the internal combustion engine.

  As described above, according to the supercharger 1, the oil discharge passage 39 is formed in the oil storage portion 37 that is a part of the flow path of the oil O formed by the C-side thrust bearing 30 and the bearing housing 8. Therefore, even when the supply pressure of the oil O is high and the flow rate of the oil O is large, the excess oil O is discharged from the oil discharge path 39 to the lower oil discharge space 18. Thereby, the pressure of the flow path formed by the C-side thrust bearing 30 and the flow rate of the oil O become appropriate, and a large amount of oil O can be prevented from leaking from the sliding contact portion 33a. In other words, the excess oil O is guided in the direction in which the sliding contact portion 33a is separated from the oil discharge passage 39, so that a large amount of oil O does not leak from the sliding contact portion 33a, and the oil O reaching the seal portion 41 is obtained. Becomes a small amount. Thereby, leakage of the oil O into the compressor can be prevented with a simple configuration, and the supercharger 1 that does not impair the performance even when the oil O is supplied at a high pressure can be realized.

  Further, the flow passage cross section of the oil discharge passage 39 allows the oil O having a flow rate sufficient for cooling to flow into the upper cooling space 19 and discharges a part of the surplus oil O to the outside. Since the movement to the portion 33a is set to be prevented, the bearing housing 8 can be sufficiently cooled and the oil O can be prevented from leaking out. Thereby, the high performance supercharger 1 can be realized by satisfying both the cooling performance and the sealing performance that have been difficult to achieve in the past.

  Further, since the oil discharge passage 39 is provided on the inner surface of the C-side thrust bearing 30 on the bearing housing 8 side, the C-side thrust bearing 30 which is a small part is machined, and the compressor housing 10 can be simply structured and machined. Oil leakage into the inside can be prevented. In addition, machining can be performed more simply than machining the bearing housing 8, which is advantageous in terms of production cost.

  Further, since the oil reservoir 37 is provided in the oil reservoir 37, the excess oil O stored in the oil reservoir 37 is discharged to the outside of the C-side thrust bearing 30 to optimize the oil capacity of the oil reservoir 37. The oil O can be effectively prevented from leaking out.

  Further, since the oil discharge passage 39 is provided below the C-side thrust bearing 30, the oil O can be discharged using gravity in addition to the pressure, and the second oil groove 36 and the oil reservoir 37 can be discharged. The oil can be circulated well without obstructing the flow of the oil O.

  Note that the operation procedures shown in the above-described embodiments, the shapes and combinations of the constituent members, and the like are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

For example, in the above embodiment, the oil discharge passage 39 is provided in the C-side thrust bearing 30, but a groove or hole communicating with the lower oil discharge space 18 may be provided in the bearing housing 8.
In the above embodiment, only one oil discharge path 39 is provided, but a plurality of oil discharge paths 39 may be provided.

It is sectional drawing which shows the whole structure of the supercharger 1 in one Embodiment of this invention. 1 is a partially enlarged view of a supercharger 1 according to an embodiment of the present invention. It is sectional drawing of the supercharger 1 in one Embodiment of this invention, Comprising: It is III-III sectional drawing in FIG. It is sectional drawing of the supercharger 1 in one Embodiment of this invention, Comprising: It is IV-IV sectional drawing in FIG. It is a figure which shows the compressor side thrust bearing 30 of the supercharger 1 in one Embodiment of this invention. It is sectional drawing of the compressor side thrust bearing 30 in one Embodiment of this invention, Comprising: It is VI-VI sectional drawing in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Supercharger 2 ... Turbine impeller 3 ... Compressor impeller 4 ... Drive shaft 7 ... Turbine housing 8 ... Bearing housing 10 ... Compressor housing 16, 17 ... Floating metal (bearing)
19 ... Upper space for cooling (oil cooling chamber)
27 ... Thrust collar 30 ... C side thrust bearing (thrust bearing)
31 ... Inner surface 33a ... Sliding contact portion 39 ... Oil discharge path O ... Oil R1 ... First flow path (flow path)
R2 ... Second channel (channel)
r ... Bearing flow path (flow path)
r1 ... Annular channel (channel)

Claims (4)

A turbine housing and a compressor housing are provided on both sides of the bearing housing, and a drive shaft is inserted into each of the housings. A turbine impeller is provided on the drive shaft in the turbine housing and the compressor housing. A compressor impeller is provided on the drive shaft in the inside,
In the supercharger in which a bearing for supporting the drive shaft is provided between the bearing housing and the drive shaft, and a flow path for circulating cooling or lubricating oil is formed in the bearing housing.
At least one of the bearings is a thrust bearing, and in the vicinity of the sliding contact portion between the thrust bearing and the drive shaft, excess oil supplied to the portion by the flow path is separated from the sliding contact portion. A turbocharger characterized in that an oil discharge passage is provided. The turbocharger according to claim 1, wherein
The supercharger, wherein the oil discharge path is provided on an inner surface of the thrust bearing. The turbocharger according to claim 2,
A thrust collar that is in sliding contact with the inner surface of the thrust bearing is fixed to the drive shaft, and oil supplied between the inner surface and the thrust collar by forming a part of the flow path on the inner surface of the thrust bearing. The turbocharger is characterized in that an oil reservoir is provided for temporarily storing the oil, and the oil discharge passage is provided so as to communicate the inside of the oil reservoir with the outside of the thrust bearing. The supercharger according to claim 3,
An oil cooling chamber for cooling is provided in an upper portion of the bearing housing on the turbine housing side, and a part of the flow path corresponding to the downstream side of the flow path formed by the inner surface of the thrust bearing is formed by the oil cooling chamber. Formed,
The cross section of the oil discharge passage is configured to discharge a part of the oil to the outside while ensuring a predetermined flow rate of the oil flowing to the oil cooling chamber, and to reduce the oil pressure in the vicinity of the sliding contact portion. The turbocharger is set so as to prevent the oil from moving to the sliding contact portion side.

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