JP2019035450A - Bearing unit and turbocharger - Google Patents

Abstract

An object of the present invention is to provide a bearing unit and a turbocharger with a simple arrangement of oil passages. A bearing unit 4 includes a thrust collar 40 including a cylindrical portion 400 fixed to a rotary shaft 50, flange portions 401f and 401r having shaft-side sliding surfaces 402f and 402r, and a diameter of the cylindrical portion 400. Ended annular thrust bearing 41 having bearing-side sliding surfaces 410f and 410r arranged on the outer side in the direction and facing shaft-side sliding surfaces 402f and 402r, shaft-side sliding surfaces 402f and 402r, and bearing-side sliding surfaces And oil passages 42 for supplying the lubricating oil O to the oil film gaps Cf and Cr partitioned between 410f and 410r. The oil passage 42 is recessed in at least one of the outer peripheral surface 400a of the cylindrical portion 400 and the inner peripheral surface 411 of the thrust bearing 41, and has oil grooves 421 that open to the oil film gaps Cf and Cr. [Selection] Figure 4

Description

  The present invention relates to a bearing unit and a turbocharger that support an axial thrust load acting on a rotating shaft.

  FIG. 7 is a sectional view in the axial direction in the vicinity of a bearing unit of a conventional turbocharger. For example, as shown in Patent Document 1, the turbocharger 100 includes a bearing unit 101. The bearing unit 101 includes a thrust collar 102, a thrust bearing 103, and an oil passage 104. The thrust collar 102 is fixed to the outer peripheral surface of the rotating shaft 105. The thrust bearing 103 has a partial arc shape (horse-shoe shape) that opens downward. An oil film gap c1 is defined between the bearing-side sliding surface 103a of the thrust bearing 103 and the shaft-side sliding surface 102a of the thrust collar 102. An oil film is formed in the oil film gap c1. The oil passage 104 is formed inside the thrust bearing 103. The oil film lubricating oil is supplied from the oil path 106 of the bearing housing to the pair of front and rear oil film gaps c <b> 1 through the oil path 104. The oil passage 104 includes an inclined oil hole 104a and a shaft oil hole 104b. The inclined oil hole 104 a is continuous with the outlet (downstream end) of the oil passage 106. The inclined oil hole 104a extends radially inward and forward from the rear surface of the thrust bearing 103. The shaft oil hole 104b is connected to the outlet of the inclined oil hole 104a. The shaft oil hole 104b extends in the front-rear direction. The outlet of the shaft oil hole 104b opens into a pair of front and rear oil film gaps c1.

Japanese Patent Laid-Open No. 9-41982

  However, according to the conventional turbocharger 100, it is necessary to connect two oil holes (inclined oil holes 104a and shaft oil holes 104b) having different extending directions inside the thrust bearing 103. Further, the endless annular outlet (downstream end) of the shaft oil hole 104b needs to be formed in the oil film gap c1, that is, the bearing side sliding surface 103a. For this reason, it is difficult to arrange the oil passage 104 with respect to the thrust bearing 103.

  Therefore, the present inventor has considered to eliminate the shaft oil hole 104b in order to simplify the arrangement work of the oil passage 104. Specifically, the inclined oil hole 104a extends to the inner peripheral surface of the thrust bearing 103, and the lubricating oil is fed back and forth through a gap c2 between the inner peripheral surface of the thrust bearing 103 and the outer peripheral surface of the thrust collar 102. The supply to the pair of bearing side sliding surfaces 103a was considered.

  However, as described above, the thrust bearing 103 has a horseshoe shape. For this reason, the inner peripheral surface, that is, the gap c <b> 2 has an end ring shape. Therefore, even if lubricating oil is supplied to the gap c2, the lubricating oil flows due to its own weight and flows down from the circumferential end of the gap c2. Thus, even if the inclined oil hole 104a is opened in the gap c2, it is difficult to supply a sufficient amount of lubricating oil to the pair of front and rear oil film gaps c1.

  Accordingly, an object of the present invention is to provide a bearing unit and a turbocharger in which an oil passage can be easily arranged inside a thrust bearing and lubricating oil can be supplied to an oil film gap.

  In order to solve the above problems, a bearing unit according to the present invention is a thrust collar comprising: a cylindrical portion fixed to a rotary shaft; and a flange portion extending radially outward from the cylindrical portion and having a shaft-side sliding surface. And an annular thrust having a bearing-side sliding surface opposed to the shaft-side sliding surface and supporting an axial thrust load acting on the rotating shaft. A bearing unit comprising: a bearing; and an oil passage for supplying an oil for forming an oil film in an oil film gap defined between the shaft side sliding surface and the bearing side sliding surface, The oil passage is recessed in at least one of the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the thrust bearing, and has an oil groove that opens into the oil film gap.

  In order to solve the above problems, a turbocharger according to the present invention is a turbocharger including the bearing unit, wherein the rotating shaft connects a compressor impeller and a turbine impeller.

  When the thrust bearing has an end ring shape, the lubricating oil tends to flow out from the circumferential end of the thrust bearing. For this reason, it is difficult to supply a sufficient amount of lubricating oil to the oil film gap. In this regard, according to the bearing unit and the turbocharger of the present invention, the oil groove is recessed in at least one of the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the thrust bearing. The oil groove opens in the oil film gap. For this reason, a sufficient amount of lubricating oil can be introduced into the oil film gap through the oil groove, even though the thrust bearing has an end ring shape. Further, since the lubricating oil can be introduced into the oil film gap through the oil groove, it is not necessary to dare to arrange the oil hole (for example, the shaft oil hole 104b shown in FIG. 7) that opens in the oil film gap in the thrust bearing. For this reason, an oil path can be easily arrange | positioned inside a thrust bearing.

  Thus, according to the bearing unit and the turbocharger of the present invention, the oil passage can be easily arranged inside the thrust bearing. In addition, the lubricating oil can be supplied to the oil film gap.

It is an axial sectional view of the turbocharger of a first embodiment. It is an enlarged view in the frame II of FIG. It is the III-III direction sectional drawing of FIG. It is a development view in the circumferential direction of the inner circumferential surface of the thrust bearing of the bearing unit of the first embodiment. It is a development view in the circumferential direction of the inner peripheral surface of the thrust bearing of the bearing unit of the second embodiment. FIG. 6 is a circumferential development view of an outer peripheral surface of a cylindrical portion of a thrust collar of another bearing unit. It is an axial sectional view near the bearing unit of a conventional turbocharger.

  Embodiments of a bearing unit and a turbocharger according to the present invention will be described below.

<First embodiment>
[Configuration of turbocharger]
First, the configuration of the turbocharger of this embodiment will be described. In the following drawings, the front-rear direction corresponds to the “axial direction” of the present invention. FIG. 1 shows an axial sectional view of the turbocharger of the present embodiment. As shown in FIG. 1, the turbocharger 1 of the present embodiment includes a journal bearing 3, a bearing unit 4, a rotating part 5, a bearing housing 90, a compressor housing 91, and a turbine housing 92. .

  Oil passages 901a and 901b and bearing housing portions 902a and 902b are formed in the bearing housing 90. Lubricating oil flows through the oil passages 901a and 901b. When viewed from the front side or the rear side, the bearing housing portion 902 a is disposed at the radial center of the bearing housing 90. The bearing housing portion 902b is disposed on the front side of the bearing housing portion 902a.

  The journal bearing 3 has a cylindrical shape. The journal bearing 3 is accommodated in the bearing accommodating portion 902a. The bearing unit 4 is accommodated in the bearing accommodating portion 902b. The bearing unit 4 will be described in detail later. The compressor housing 91 is disposed on the front side of the bearing housing 90. The turbine housing 92 is disposed on the rear side of the bearing housing 90.

  The rotating part 5 is rotatable with respect to the bearing housing 90. The rotating unit 5 includes a rotating shaft 50, a compressor impeller 51, and a turbine impeller 52. The rotating shaft 50 penetrates the bearing housing 90 in the front-rear direction. The rotating shaft 50 is rotatably supported by the journal bearing 3 from the radially outer side. The compressor impeller 51 is attached to the front end of the rotating shaft 50. The turbine impeller 52 is connected to the rear end of the rotary shaft 50. That is, the rotating shaft 50 connects the compressor impeller 51 and the turbine impeller 52.

[Configuration of bearing unit]
Next, the structure of the bearing unit of this embodiment is demonstrated. FIG. 2 shows an enlarged view in the frame II of FIG. FIG. 3 shows a cross-sectional view in the III-III direction of FIG. FIG. 4 shows a development in the circumferential direction of the inner peripheral surface of the thrust bearing of the bearing unit of the present embodiment. The angle in FIG. 4 is a central angle around the axis A of the rotation shaft 50 as shown in FIG. The central angle advances from the upstream side in the flow direction of the lubricating oil O toward the downstream side, with the position immediately below being 0 °.

  As shown in FIGS. 2 and 3, the bearing unit 4 includes a thrust collar 40, a thrust bearing 41, and an oil passage 42. The thrust collar 40 is an integral object and is fixed to the outer peripheral surface of the rotating shaft 50. The thrust collar 40 can rotate around the axis A of the rotation shaft 50 together with the rotation shaft 50. The thrust collar 40 includes a cylindrical portion 400 and a pair of front and rear flange portions 401f and 401r. The cylinder part 400 has a cylindrical shape extending in the front-rear direction. The pair of front and rear flange portions 401f and 401r project radially outward from both front and rear ends of the cylindrical portion 400. The flange portions 401f and 401r have an annular shape. A shaft side sliding surface 402f is disposed on the rear surface (inner surface in the axial direction) of the front flange portion 401f. Similarly, a shaft side sliding surface 402r is disposed on the front surface (inner surface in the axial direction) of the rear flange portion 401r.

  As shown in FIG. 2, the thrust bearing 41 supports a thrust load that acts on the rotating shaft 50. As shown in FIG. 3, the thrust bearing 41 has a partial arc shape (horse-shoe shape) that opens downward. The thrust bearing 41 is disposed on the radially outer side of the cylindrical portion 400. As shown in FIG. 2, a pair of front and rear bearing-side sliding surfaces 410 f and 410 r are disposed on both front and rear surfaces (axially outer surfaces) of the central portion in the radial direction of the thrust bearing 41.

  As shown in FIGS. 3 and 4, the front bearing-side sliding surface 410 f includes three pad portions Pf. The three pad portions Pf are arranged in a circumferential direction (a circumferential direction centered on the rotation shaft 50. That is, a flow direction of the lubricating oil O in oil film gaps Cf and Cr and an oil supply gap Co to be described later. Are arranged side by side (clockwise direction in FIG. 3). The pad portion Pf includes a tapered portion Tf and a land portion Lf. The taper portion Tf has an inclined surface shape in which the altitude in the front-rear direction increases from the upstream side in the flow direction of the lubricating oil O (rear side in the rotational direction) to the downstream side (front side in the rotational direction). The land portion Lf continues to the downstream side of the tapered portion Tf. The land portion Lf has a planar shape with a constant altitude in the front-rear direction. The bearing side sliding surface 410f faces the shaft side sliding surface 402f. An oil film gap Cf is defined between the bearing side sliding surface 410f and the shaft side sliding surface 402f.

  As shown in FIG. 4, the rear bearing side sliding surface 410r includes three pad portions Pr. The configuration of the pad portion Pr is the same as the configuration of the pad portion Pf. That is, the pad portion Pr includes a tapered portion Tr and a land portion Lr. The bearing side sliding surface 410r faces the shaft side sliding surface 402r. An oil film gap Cr is defined between the bearing side sliding surface 410r and the shaft side sliding surface 402r. Oil films are formed in the oil film gaps Cf and Cr. For this reason, the thrust collar 40 is slidable with respect to the thrust bearing 41.

  As shown in FIGS. 3 and 4, the inner peripheral surface 411 of the thrust bearing 41 has an end ring shape. On the other hand, the outer peripheral surface 400a of the cylindrical part 400 has an endless annular shape. An oil supply gap Co is defined between the inner peripheral surface 411 and the outer peripheral surface 400a.

  As shown in FIGS. 3 and 4, the oil passage 42 includes an inclined oil hole 420 and an oil groove 421. As shown by a dotted line in FIG. 3, the inclined oil hole 420 is disposed inside the thrust bearing 41. As shown in FIG. 2, the inlet (upstream end) of the inclined oil hole 420 opens on the rear surface of the thrust bearing 41. The inlet is connected to the outlet of the oil passage 901 a of the bearing housing 90. As shown in FIG. 4, the outlet (downstream end) of the inclined oil hole 420 opens to the inner peripheral surface 411 of the thrust bearing 41.

  As shown in FIG. 4, the oil groove 421 is recessed in the inner peripheral surface 411. The oil groove 421 extends in a dendritic shape. The oil groove 421 includes a plurality of first sections 421af and 421ar and a single second section 421b. The second section 421b is disposed at the center in the front-rear direction of the inner peripheral surface 411. The second section 421b extends over substantially the entire length in the circumferential direction of the inner peripheral surface 411. The inlet (upstream end) of the second section 421b is connected to the outlet of the inclined oil hole 420.

  The entrances (upstream ends) of the plurality of first sections 421af on the front side are each connected to the second section 421b. As shown in FIG. 3, the outlets (downstream ends) of the plurality of first sections 421af each open to the radially inner end of the bearing side sliding surface 410f. As shown in FIG. 4, the first section 421af extends in a direction including the front-rear direction and the circumferential direction. The outlet is arranged to be shifted downstream with respect to the inlet. The plurality of first sections 421af are juxtaposed in parallel with each other. The plurality of first sections 421af include a plurality of taper section 421af1 and a plurality of land section 421af2. The plurality of taper section 421af1 and the plurality of land section 421af2 are alternately arranged in the circumferential direction. The outlet of the taper section 421af1 opens to the upstream portion of the taper section Tf. The exit of the land section 421af2 opens to the upstream portion of the land section Lf.

  The entrances of the plurality of first sections 421ar on the rear side are each connected to the second section 421b. The outlets of the plurality of first sections 421ar each open to the radially inner end of the bearing side sliding surface 410r. As shown in FIG. 4, the first section 421ar extends in a direction including the front-rear direction and the circumferential direction. The outlet is arranged to be shifted downstream with respect to the inlet. The plurality of first sections 421ar are juxtaposed in parallel with each other. The plurality of first sections 421ar include a plurality of taper section 421ar1 and a plurality of land section 421ar2. The plurality of taper section 421ar1 and the plurality of land section 421ar2 are alternately arranged in the circumferential direction. The outlet of the taper section 421ar1 is open to the upstream portion of the taper section Tr. The exit of the land section 421ar2 opens to the upstream portion of the land section Lr. Thus, the rear first section 421ar and the front first section 421af are arranged line-symmetrically with the second section 421b as a boundary.

[Lubricant oil flow]
Next, the flow of the lubricating oil in the bearing unit of this embodiment will be described. When the turbocharger 1 is driven, as shown in FIG. 2, the lubricating oil O flows into the inclined oil hole 420 of the oil passage 42 through the oil passage 901a. As shown in FIG. 3, the lubricating oil O that has flowed flows through the inclined oil holes 420 from the radially outer side toward the radially inner side, and then flows into the oil supply gap Co. As shown in FIG. 4, the lubricating oil O that has flowed into the oil supply gap Co flows along the oil groove 421 as the rotary shaft 50, that is, the thrust collar 40 rotates. Specifically, the lubricating oil O flows in the second section 421b from the upstream side toward the downstream side.

  Further, the lubricating oil O flows from the rear side to the front side and from the upstream side to the downstream side along the first section 421af on the front side, and flows into the oil film gap Cf. By the flow, the lubricating oil O is supplied to all the taper portions Tf and all the land portions Lf. The lubricating oil O supplied to the taper portion Tf via the taper portion section 421af1 flows through the taper portion Tf from the rear side to the front side and from the upstream side to the downstream side. Due to the flow, the oil pressure of the lubricating oil O increases. The lubricating oil O supplied to the land portion Lf through the taper portion Tf and the land portion section 421af2 flows through the land portion Lf from the upstream side toward the downstream side. At this time, the lubricating oil O forms an oil film. By the oil film, the bearing side sliding surface 410f supports the shaft side sliding surface 402f in a rotatable manner.

  Similarly, the lubricating oil O flows from the front side to the rear side and from the upstream side to the downstream side along the rear first section 421ar and flows into the oil film gap Cr. By this flow, the lubricating oil O is supplied to all the taper portions Tr and all the land portions Lr. The lubricating oil O supplied to the tapered portion Tr via the tapered portion section 421ar1 flows through the tapered portion Tr from the front side to the rear side and from the upstream side to the downstream side. Due to the flow, the oil pressure of the lubricating oil O increases. The lubricating oil O supplied to the land portion Lr via the taper portion Tr and the land portion section 421ar2 flows in the land portion Lr from the upstream side toward the downstream side. At this time, the lubricating oil O forms an oil film. With the oil film, the bearing side sliding surface 410r supports the shaft side sliding surface 402r in a rotatable manner. The lubricating oil O used in the oil film is discharged to the outside of the bearing housing 90 through an oil passage 901b shown in FIG.

[Function and effect]
Next, functions and effects of the bearing unit and the turbocharger of this embodiment will be described. As shown in FIG. 4, when the thrust bearing 41, that is, the oil supply gap Co has an end ring shape, even if the lubricant oil O is supplied to the oil supply gap Co, the lubricant oil O flows by its own weight and is used for oil supply. It tends to flow down from the circumferential end of the gap Co. For this reason, it is difficult to supply a sufficient amount of the lubricating oil O to the oil film gaps Cf and Cr. In this regard, an oil groove 421 is recessed in the inner peripheral surface 411. The oil groove 421 opens to the oil film gaps Cf and Cr. For this reason, a sufficient amount of the lubricating oil O can be introduced into the oil film gaps Cf and Cr through the oil groove 421, even though the oil supply gap Co has an end ring shape.

  Further, since the lubricating oil O can be introduced into the oil film gaps Cf and Cr via the oil groove 421, oil holes (for example, shaft oil holes 104b shown in FIG. 7) opened in the oil film gaps Cf and Cr in the thrust bearing 41. There is no need to place it. The oil hole disposed inside the thrust bearing 41 is only the inclined oil hole 420. For this reason, a part of the oil passage 42 can be easily arranged inside the thrust bearing 41.

  The oil groove 421 includes first sections 421af and 421ar extending in a direction including at least the axial direction. For this reason, the lubricating oil O can be flowed in the direction including the axial direction. Further, the outlets of the first sections 421af and 421ar are opened to the oil film gaps Cf and Cr. Therefore, the lubricating oil O can be supplied to the oil film gaps Cf and Cr. Moreover, the supply position of the lubricating oil O to the oil film gaps Cf and Cr can be adjusted by adjusting the circumferential position of the outlet.

  The oil groove 421 includes a second section 421b extending in a direction including at least the circumferential direction. For this reason, the lubricating oil O can be flowed in the direction including the circumferential direction. The second section 421b is connected to the first sections 421af and 421ar. For this reason, the lubricating oil O can be supplied to the first sections 421af and 421ar. Further, the lubricating oil O can be distributed to the plurality of first sections 421af and 421ar arranged in the circumferential direction.

  Out of the first sections 421af and 421ar, the outlets of the taper section 421af1 and 421ar1 open to the tapered sections Tf and Tr. For this reason, the lubricating oil O can be supplied to the land portions Lf and Lr via the tapered portions Tf and Tr. That is, the lubricating oil O can be supplied to the land portions Lf and Lr after being boosted by the taper portions Tf and Tr.

  By the way, when the lubricating oil O is supplied to the land portions Lf and Lr via the tapered portions Tf and Tr, the lubricating oil O may escape from the tapered portions Tf and Tr during the pressure increase. In this case, the amount of lubricating oil O supplied to the land portions Lf and Lr is reduced. In this regard, out of the first sections 421af and 421ar, the outlets of the land sections 421af2 and 421ar2 are open to the land sections Lf and Lr. For this reason, the lubricating oil O can be directly supplied to the land portions Lf and Lr without passing through the taper portions Tf and Tr. Therefore, a sufficient amount of lubricating oil O can be reliably supplied to the land portions Lf and Lr.

  The outlet of the inclined oil hole 420 opens at the upstream end of the second section 421b. For this reason, the lubricating oil O can be spread over the entire circumferential length of the second section 421b. Therefore, the lubricating oil O can be spread over all the pad portions Pf and Pr.

<Second embodiment>
The only difference between the bearing unit and turbocharger of the present embodiment and the bearing unit and turbocharger of the first embodiment is the shape of the first section. Here, only differences will be described.

  FIG. 5 shows a development in the circumferential direction of the inner peripheral surface of the thrust bearing of the bearing unit of the present embodiment. In addition, about the site | part corresponding to FIG. 4, it shows with the same code | symbol. As shown in FIG. 5, groove-side tapered portions tf and tr are arranged in the first sections 421af and 421ar over the entire length. The groove widths of the groove-side taper portions tf and tr are gradually narrowed toward the outlet.

  The bearing unit and the turbocharger of the present embodiment and the bearing unit and the turbocharger of the first embodiment have the same operational effects with respect to the parts having the same configuration. The first sections 421af and 421ar include groove-side tapered portions tf and tr. For this reason, after the pressure of the lubricating oil O is increased, it can be supplied to the oil film gaps Cf and Cr. Therefore, it is possible to prevent the lubricating oil O from flowing backward from the oil film gaps Cf and Cr to the first sections 421af and 421ar.

<Others>
The embodiments of the bearing unit and the turbocharger according to the present invention have been described above. However, the embodiment is not particularly limited to the above embodiment. Various modifications and improvements that can be made by those skilled in the art are also possible.

  FIG. 6 shows a circumferential development of the outer peripheral surface of the cylindrical portion of the thrust collar of the other bearing unit. In addition, about the site | part corresponding to FIG. 4, it shows with the same code | symbol. As shown in FIG. 6, an oil groove 421 may be disposed on the outer peripheral surface 400 a of the cylindrical portion 400. The thrust collar 40 rotates together with the rotating shaft 50 shown in FIG. For this reason, the outlets of the first sections 421af and 421ar are shifted from the inlet toward the upstream side. When passing the radially inner side of the outlet of the inclined oil hole 420, the lubricating oil O is supplied to the second section 421b.

  As in the bearing unit of the present embodiment, the oil groove 421 may be disposed on the outer peripheral surface 400a of the cylindrical portion 400. This simplifies the operation of disposing the oil groove 421 as compared to the case of disposing the oil groove 421 on the inner peripheral surface 411 of the thrust bearing 41. Further, the lubricating oil O can be spread over the entire circumferential length of the second section 421b regardless of the position of the outlet of the inclined oil hole 420. Therefore, the lubricating oil O can be spread over all the pad portions Pf and Pr (see FIG. 4).

  Further, the oil groove 421 may be disposed in the thrust bearing 41 and the thrust collar 40. For example, you may arrange | position the 2nd area 421b in the outer peripheral surface 400a of the cylinder part 400. FIG. In addition, the first sections 421af and 421ar may be disposed on the inner peripheral surface 411 of the thrust bearing 41.

  The shape (extended shape, cross-sectional shape), extending direction, position, and number of arrangements of the inclined oil hole 420, the first sections 421af and 421ar, and the second section 421b are not particularly limited. The outlet of the inclined oil hole 420 may open to a place other than the upstream end of the second section 421b (for example, the 120 ° position, 180 ° position, 240 ° position, etc. shown in FIG. 4). The total circumferential length of the inner peripheral surface 411 shown in FIG. 4 is not particularly limited. For example, it may be 210 °, 240 °, 300 °, 330 °, and the like. The extending direction of the first sections 421af and 421ar may be only the axial direction. The extending direction of the second section 421b may be a direction including the circumferential direction and the axial direction. The groove side taper portions tf and tr shown in FIG. 5 may be arranged only in a part of the first sections 421af and 421ar. For example, it may be arranged only in the vicinity of the exits of the first sections 421af and 421ar.

  The thrust bearing 41 may have an endless annular shape. That is, the total circumferential length of the inner peripheral surface 411 shown in FIG. 4 may be 360 °. Even in this case, the lubricating oil O can be supplied to the oil film gaps Cf and Cr through the oil passage 42.

  The oil groove 421 may not include the second section 421b. In this case, the lubricating oil O can be moved in the circumferential direction as the thrust collar 40 rotates through the oil supply gap Co. The first sections 421af and 421ar may include only the taper section 421af1 and 421ar1. Further, the first sections 421af and 421ar may include only the land section 421af2 and 421ar2.

  1: turbocharger, 3: journal bearing, 4: bearing unit, 5: rotating part, 40: thrust collar, 41: thrust bearing, 42: oil passage, 50: rotating shaft, 51: compressor impeller, 52: turbine impeller, 90: bearing housing, 91: compressor housing, 92: turbine housing, 400: tube portion, 400a: outer peripheral surface, 401f: flange portion, 401r: flange portion, 402f: shaft side sliding surface, 402r: shaft side sliding surface , 410f: bearing side sliding surface, 410r: bearing side sliding surface, 411: inner peripheral surface, 420: inclined oil hole, 421: oil groove, 421af: first section, 421af1: section for taper portion, 421af2: land Section section, 421ar: first section, 421ar1: section for taper section, 421ar2: section for land section, 421b: Two sections, 901a: oil passage, 901b: oil passage, 902a: bearing housing portion, 902b: bearing housing portion, A: shaft center, Cf: oil film gap, Co: oil supply gap, Cr: oil film gap, Lf: Land part, Lr: Land part, O: Lubricating oil, Pf: Pad part, Pr: Pad part, Tf: Tapered part, Tr: Tapered part, tf: Groove side taper part, tr: Groove side taper part

Claims (7)

A thrust collar comprising: a cylindrical portion fixed to the rotating shaft; and a flange portion extending radially outward from the cylindrical portion and having a shaft-side sliding surface;
An endless annular thrust bearing disposed on a radially outer side of the cylindrical portion, having a bearing-side sliding surface facing the shaft-side sliding surface, and supporting an axial thrust load acting on the rotating shaft; ,
An oil passage for supplying lubricating oil for forming an oil film in an oil film gap defined between the shaft side sliding surface and the bearing side sliding surface;
A bearing unit comprising:
The bearing is characterized in that the oil passage has an oil groove that is recessed in at least one of the outer peripheral surface of the cylindrical portion and the inner peripheral surface of the thrust bearing and opens into the oil film gap.   2. The bearing unit according to claim 1, wherein the oil groove has a first section extending at least in a direction including the axial direction and having an outlet opening to the oil film gap.   The bearing unit according to claim 2, wherein the oil groove has a second section that extends at least in a direction including a circumferential direction and continues to the first section. The bearing-side sliding surface has a pad portion having a tapered portion and a land portion connected to the tapered portion,
The bearing unit according to claim 2 or 3, wherein the outlet of the first section opens in the tapered portion. The bearing-side sliding surface has a pad portion having a tapered portion and a land portion connected to the tapered portion,
The bearing unit according to claim 2 or 3, wherein the outlet of the first section opens in the land portion.   The bearing unit according to any one of claims 2 to 5, wherein the first section has a groove-side taper portion whose groove width becomes narrower toward the outlet. A turbocharger comprising the bearing unit according to any one of claims 1 to 6,
The rotating shaft is a turbocharger that connects a compressor impeller and a turbine impeller.

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