WO2022224491A1 - Supercharger - Google Patents

Abstract

A supercharger comprising: a shaft; a rolling bearing having an inner ring mounted on the shaft and an outer ring disposed around the inner ring; and a restriction member 40 including an end surface 41 facing a side surface 62a of the outer ring. When viewed from the center axis direction of the shaft, the end surface 41 includes an oil guide groove 45 extending inward from the outer side of the side surface 62a of the outer ring, and the entire oil guide groove 45 is positioned within a range Ar1 larger than 0 degrees and smaller than 90 degrees in a rotation direction R of the shaft with respect to a vertical axis Z extending upward from the center axis of the shaft.

Description

supercharger

This disclosure relates to turbochargers. This application claims the benefit of priority based on Japanese Patent Application No. 2021-73664 filed on April 23, 2021, the content of which is incorporated herein by reference.

The supercharger may have rolling bearings that support the shaft. For example, the turbocharger of Patent Document 1 includes a pair of rolling bearings. The side surface of the outer ring of one rolling bearing faces the side wall of the housing. A side wall of the housing has an oil supply groove. The oil groove extends radially of the shaft and is inclined with respect to a vertical axis extending upward from the shaft.

Also, for example, the turbocharger of Patent Document 2 includes a pair of rolling bearings. The side surface of the outer ring of one rolling bearing faces the damper retainer. The damper stop has a generally toroidal shape. However, the lower portion of the damper stop has a notch and is circumferentially discontinuous. The damper restrainer has an oil supply groove. The lubricating groove includes a generally arcuate groove. The arcuate groove is spaced from the inner peripheral edge of the damper stop by a projection.

WO2020/021908 Japanese Utility Model Laid-Open No. 60-43137

In a turbocharger, it is desirable to efficiently guide the oil in the discharge direction.

An object of the present disclosure is to provide a turbocharger that can efficiently guide oil in the discharge direction in consideration of the above problems.

In order to solve the above problems, a turbocharger according to one aspect of the present disclosure includes a rolling bearing having a shaft, an inner ring attached to the shaft, and an outer ring arranged around the inner ring; A regulating member including opposing end faces, the end faces including guide oil grooves extending inwardly from the outside of the side surface of the outer ring when viewed from the direction of the central axis of the shaft, the entire guide oil grooves extending along the central axis of the shaft. a regulating member positioned within a range of more than 0 degrees and less than 90 degrees in the rotational direction of the shaft with respect to a vertical axis extending upward from the shaft.

The turbocharger may further include a housing including a bearing hole that accommodates the rolling bearing, and a compressor impeller provided on the shaft outside the bearing hole, and the restricting member is positioned between the bearing hole and the compressor impeller. may be placed.

When the regulating member is arranged between the bearing hole and the compressor impeller, the end face of the regulating member is located inside the guide oil groove in the radial direction of the shaft and is connected to the guide oil groove. A groove, which is a circumferential oil groove extending along the circumferential direction of the shaft, and a projection located inside the circumferential oil groove in the radial direction of the shaft and protruding in the direction of the central axis of the shaft. may contain.

The turbocharger may further include a housing including a bearing hole that accommodates the rolling bearing, and a turbine impeller that is provided on the shaft outside the bearing hole, and the regulating member is positioned between the bearing hole and the turbine impeller. may be placed.

The guide oil groove may have a central axis extending along the radial direction of the shaft, and the central axis of the guide oil groove may be positioned at 45 degrees to the vertical axis in the direction of rotation of the shaft. good.

According to the present disclosure, oil can be efficiently guided in the discharge direction.

FIG. 1 is a schematic cross-sectional view showing a turbocharger according to an embodiment. FIG. 2 is a schematic enlarged cross-sectional view of part A in FIG. FIG. 3 is a schematic plan view showing a bearing retainer plate. FIG. 4 is a schematic cross-sectional view taken along line IV-IV in FIG. FIG. 5 is a schematic cross-sectional view taken along line VV in FIG. FIG. 6 is a schematic plan view showing a bearing retainer plate according to another embodiment. FIG. 7 is a schematic cross-sectional view taken along line VII-VII in FIG. FIG. 8 is a graph showing evaluation results of oil leakage.

Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. Specific dimensions, materials, numerical values, and the like shown in such embodiments are merely examples for facilitating understanding, and do not limit the present disclosure unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are given the same reference numerals to omit redundant description, and elements that are not directly related to the present disclosure are omitted from the drawings. do.

FIG. 1 is a schematic cross-sectional view showing the turbocharger TC according to the embodiment. For example, the supercharger TC is applied to an engine. The supercharger TC includes a housing 1 , a shaft 7 , a turbine impeller 8 and a compressor impeller 9 .

With respect to the orientation of the turbocharger TC, in this disclosure the central axial, radial and circumferential directions of the shaft 7 are simply referred to as "central axial", "radial" and "circumferential" respectively, unless otherwise indicated. may be referred to as "direction".

The housing 1 includes a bearing housing 2, a turbine housing 3 and a compressor housing 4. One end of the bearing housing 2 is connected to the turbine housing 3 in the central axis direction by a fastening mechanism 21a such as a G coupling. In the central axis direction, the other end of the bearing housing 2 is connected to the compressor housing 4 by a fastening mechanism 21b such as a fastening bolt.

The bearing housing 2 includes bearing holes 22 . The bearing hole 22 extends in the center axis direction inside the bearing housing 2 . One end of the bearing hole 22 is defined by a side wall 30 of the bearing housing 2 in the central axis direction. The side wall 30 is positioned between the turbine impeller 8 and the bearing hole 22 in the central axis direction. The other end of the bearing hole 22 is defined by a bearing retainer plate 40 in the central axis direction. The bearing retainer plate 40 is positioned between the compressor impeller 9 and the bearing hole 22 in the central axis direction.

The side wall 30 protrudes radially inward with respect to the inner peripheral surface of the bearing hole 22 . Side wall 30 is integral with bearing housing 2 . However, in other embodiments, sidewall 30 may be separate from bearing housing 2 or attached to bearing housing 2 . Sidewall 30 includes an end surface 31 . The end face 31 defines one end of the bearing hole 22 in the central axis direction. Details of the side wall 30 will be described later.

The bearing retainer plate 40 is separate from the bearing housing 2 and attached to the surface 24 of the bearing housing 2 . Surface 24 extends perpendicular to the inner peripheral surface of bearing hole 22 . For example, the bearing retainer plate 40 is fitted to the bearing housing 2 . Bearing retainer plate 40 includes a first end surface 41 . The first end surface 41 defines the other end of the bearing hole 22 in the center axis direction. The details of the bearing retainer plate 40 will be described later.

The bearing hole 22 accommodates a pair of rolling bearings 50,60. Rolling bearings 50 and 60 rotatably support shaft 7 . The pair of rolling bearings 50, 60 are separated from each other in the central axis direction. In this disclosure, the rolling bearing adjacent sidewall 30 may be referred to as primary bearing 50 . In the present disclosure, the rolling bearing adjacent bearing retainer plate 40 may be referred to as secondary bearing 60 .

A turbine impeller 8 is provided at a first end of the shaft 7 in the central axis direction. The turbine impeller 8 is positioned outside the bearing hole 22 in the central axis direction. A turbine impeller 8 is rotatably housed in the turbine housing 3 . A compressor impeller 9 is provided at a second end of the shaft 7 opposite to the first end in the central axis direction. The compressor impeller 9 is positioned outside the bearing hole 22 in the central axis direction. A compressor impeller 9 is rotatably housed in the compressor housing 4 .

The compressor housing 4 includes an air intake 10 at the end opposite to the bearing housing 2 in the central axis direction. The intake port 10 is connected to an air cleaner (not shown). Bearing housing 2 and compressor housing 4 define a diffuser flow path 11 therebetween. The diffuser flow path 11 expands from the inner side to the outer side in the radial direction. The diffuser channel 11 has an annular shape. The diffuser flow path 11 communicates with the intake port 10 via the compressor impeller 9 .

The compressor housing 4 includes a compressor scroll flow path 12. The compressor scroll passage 12 is located radially outside the compressor impeller 9 . The compressor scroll channel 12 communicates with the diffuser channel 11 . Further, the compressor scroll flow path 12 communicates with an intake port of an engine (not shown). When the compressor impeller 9 rotates, air is drawn into the compressor housing 4 through the intake port 10 . The intake air is accelerated by centrifugal force while passing through the spaces between the blades of the compressor impeller 9 . The accelerated air is pressurized in diffuser passage 11 and compressor scroll passage 12 . The pressurized air flows out from a discharge port (not shown) and is led to the intake port of the engine.

The turbine housing 3 includes a discharge port 13 at the end opposite to the bearing housing 2 in the center axis direction. The discharge port 13 is connected to an exhaust gas purification device (not shown). Turbine housing 3 includes flowpath 14 and turbine scroll flowpath 15 . The turbine scroll passage 15 is located radially outside the turbine impeller 8 . The flowpath 14 is located between the turbine impeller 8 and the turbine scroll flowpath 15 .

The turbine scroll passage 15 communicates with a gas inlet (not shown). The gas inlet receives exhaust gas discharged from an exhaust manifold of an engine (not shown). Turbine scroll channel 15 communicates with channel 14 . The flow path 14 communicates with the discharge port 13 via the turbine impeller 8 . Exhaust gas is led from the gas inlet to the turbine scroll passage 15 and then to the discharge port 13 via the passage 14 and the turbine impeller 8 . The exhaust gases rotate the turbine impeller 8 while passing through the spaces between the blades of the turbine impeller 8 .

The rotational force of the turbine impeller 8 is transmitted to the compressor impeller 9 via the shaft 7. As the compressor impeller 9 rotates, the air is pressurized as described above. Thus, pressurized air is directed to the intake of the engine.

FIG. 2 is a schematic enlarged cross-sectional view of part A in FIG. Bearing housing 2 includes a main oil passage 23 . The main oil passage 23 extends in the central axis direction. The main oil passage 23 extends parallel to the bearing hole 22 . The main oil passage 23 is positioned above the bearing hole 22 .

The bearing hole 22 and the main oil passage 23 open onto the surface 24 of the bearing housing 2 . As noted above, the surface 24 is fitted with a bearing retainer plate 40 . The bearing restraining plate 40 closes the opening of the main oil passage 23 .

The main oil passage 23 communicates with the through hole 25 . A through hole 25 is formed in the bearing housing 2 . The through hole 25 extends from the outer wall of the bearing housing 2 to the main oil passage 23 . Oil is supplied to the main oil passage 23 from an oil pump (not shown) through a through hole 25 .

The bearing housing 2 includes a first oil passage 26 and a second oil passage 27. Each of first oil passage 26 and second oil passage 27 opens into main oil passage 23 . Also, each of the first oil passage 26 and the second oil passage 27 opens into the bearing hole 22 . Each of first oil passage 26 and second oil passage 27 connects main oil passage 23 and bearing hole 22 . The first oil passage 26 is provided at a position corresponding to the first bearing 50 in the central axis direction and opens toward the first bearing 50 . The second oil passage 27 is provided at a position corresponding to the second bearing 60 in the central axis direction and opens toward the second bearing 60 .

The bearing housing 2 includes a lower wall 29. The lower wall 29 defines the lower portion of the bearing hole 22 in the radial direction. The lower wall 29 includes an oil drain hole 29a. The oil drain hole 29a penetrates the lower wall 29 in the vertical direction. For example, the oil drain hole 29a is positioned between the first oil passage 26 and the second oil passage 27 in the central axis direction. That is, the oil drain hole 29a is located between the first bearing 50 and the second bearing 60 in the center axis direction.

A part of the shaft 7 is accommodated in the bearing hole 22 . The shaft 7 includes a large diameter portion 7a, a medium diameter portion 7b and a small diameter portion 7c. The medium-diameter portion 7b is located between the side wall 30 and the bearing retainer plate 40 in the central axis direction. The large-diameter portion 7a is positioned between the first end portion of the shaft 7 and the medium-diameter portion 7b in the central axis direction. The small diameter portion 7c is located between the second end of the shaft 7 and the medium diameter portion 7b in the central axis direction. The outer diameter of the medium diameter portion 7b is smaller than the outer diameter of the large diameter portion 7a. The outer diameter of the small diameter portion 7c is smaller than the outer diameter of the medium diameter portion 7b.

The shaft 7 includes a first step surface 7d and a second step surface 7e. The first stepped surface 7d is located between the large diameter portion 7a and the medium diameter portion 7b in the central axis direction. The first step surface 7d radially extends from the outer peripheral surface of the large diameter portion 7a to the outer peripheral surface of the intermediate diameter portion 7b. The second stepped surface 7e is positioned between the medium diameter portion 7b and the small diameter portion 7c in the central axis direction. The second step surface 7e radially extends from the outer peripheral surface of the medium diameter portion 7b to the outer peripheral surface of the small diameter portion 7c.

The first bearing 50 includes an inner ring 51, an outer ring 52, multiple rolling elements 53, and a retainer 54. The inner ring 51 is attached to the outer peripheral surface of the medium diameter portion 7 b of the shaft 7 . The inner ring 51 rotates together with the shaft 7 . The outer ring 52 is provided radially outside the inner ring 51 . The outer ring 52 faces the inner peripheral surface of the bearing hole 22 . A plurality of rolling elements 53 are arranged between the inner ring 51 and the outer ring 52 . The retainer 54 retains the plurality of rolling elements 53 .

The second bearing 60 includes an inner ring 61, an outer ring 62, multiple rolling elements 63, and a retainer 64. The inner ring 61 is attached to the outer peripheral surface of the medium diameter portion 7 b of the shaft 7 . The inner ring 61 rotates together with the shaft 7 . The outer ring 62 is provided radially outside the inner ring 61 . The outer ring 62 faces the inner peripheral surface of the bearing hole 22 . A plurality of rolling elements 63 are arranged between the inner ring 61 and the outer ring 62 . A retainer 64 retains a plurality of rolling elements 63 .

In the present disclosure, of the side surfaces 51a, 51b, 61a, 61b of the inner ring 51 of the first bearing 50 and the inner ring 61 of the second bearing 60, the side surfaces facing each other in the direction of the central axis are referred to as "inner side surfaces" 51b, 61b. and the side opposite the inner side 51b, 61b may be referred to as the "outer side" 51a, 61a.

Similarly, in the present disclosure, of the side surfaces 52a, 52b, 62a, and 62b of the outer ring 52 of the first bearing 50 and the outer ring 62 of the second bearing 60, the side surfaces facing each other in the direction of the central axis are referred to as the "inner side surface" 52b, 62b, and the side opposite the inner surface 52b, 62b may be referred to as the "outer surface" 52a, 62a.

The outer side surface 51a of the inner ring 51 of the first bearing 50 contacts the first stepped surface 7d of the shaft 7 in the central axis direction. Further, the outer surface 52a of the outer ring 52 of the first bearing 50 faces the end surface 31 of the side wall 30 in the center axis direction.

A spacer 70 is provided between the inner ring 51 and the inner ring 61 in the middle diameter portion 7 b of the shaft 7 . Spacer 70 has a generally cylindrical shape. The shaft 7 is inserted into the spacer 70 . In other embodiments, instead of spacer 70, a spring and spring receiver may be provided.

The inner side surface 51b of the inner ring 51 of the first bearing 50 contacts one end of the spacer 70 in the center axis direction. The inner side surface 61b of the inner ring 61 of the second bearing 60 contacts the other end of the spacer 70 in the center axis direction.

An oil slinger 80 is attached to the small diameter portion 7c of the shaft 7. The oil slinger 80 scatters the oil radially outward. The oil slinger member 80 is provided radially inside the bearing retainer plate 40 . The oil slinger member 80 and the bearing retainer plate 40 are spaced apart in the radial direction.

The outer side surface 61a of the inner ring 61 of the second bearing 60 contacts the oil slinger member 80 in the central axis direction. Further, the outer side surface 62a of the outer ring 62 of the second bearing 60 faces the bearing restraining plate 40 in the center axis direction.

The first bearing 50, the spacer 70, the second bearing 60, the oil slinger member 80, and the compressor impeller 9 are attached to the shaft 7 in this order from the end of the shaft 7 on the compressor impeller 9 side. A tightening bolt attached to the second end of the shaft 7 applies a compressive stress to these members in the central axis direction, thereby applying an axial force to the shaft 7 . The inner ring 51 of the first bearing 50 , the spacer 70 , the inner ring 61 of the second bearing 60 , the oil slinger member 80 and the compressor impeller 9 rotate integrally with the shaft 7 .

The outer peripheral surface 52c of the outer ring 52 of the first bearing 50 includes a notch 55. The notch 55 has an annular shape. The notch 55 adjoins the outer surface 52a. The outer diameter of the outer surface 52a is smaller than the diameter of the outer peripheral surface 52c by the length of the notch 55 in the radial direction.

The outer peripheral surface 62c of the outer ring 62 of the second bearing 60 includes a notch 65. The notch 65 has an annular shape. The notch 65 is adjacent to the outer surface 62a. The outer diameter of the outer surface 62a is smaller than the diameter of the outer peripheral surface 62c by the length of the notch 65 in the radial direction.

When a thrust load directed toward the turbine impeller 8 acts on the shaft 7 , the outer ring 52 of the first bearing 50 presses the side wall 30 . Therefore, the side wall 30 functions as a restricting member that restricts axial movement of the outer ring 52 . Further, when a thrust load directed toward the compressor impeller 9 acts on the shaft 7 , the outer ring 62 of the second bearing 60 presses the bearing restraining plate 40 . Therefore, the bearing retainer plate 40 functions as a restricting member that restricts axial movement of the outer ring 62 . According to the configuration as described above, the movement of the shaft 7 due to the thrust load is stopped by the side wall 30 and the bearing restraining plate 40 .

In the present embodiment, the supercharger TC does not have rotation stoppers for the outer rings 52 and 62 . The outer ring 52 is circumferentially rotatable with respect to the bearing housing 2 when not pressing against the side wall 30 . Similarly, the outer ring 62 is circumferentially rotatable with respect to the bearing housing 2 when the bearing retaining plate 40 is not pressed. When the shaft 7 rotates, the inner rings 51 and 61 rotate together with the shaft 7 . The rolling elements 53 and 63 rotate as the inner rings 51 and 61 rotate. The rolling elements 53, 63 move in the circumferential direction. The outer rings 52, 62 rotate in the circumferential direction as the rolling elements 53, 63 rotate and move, or as the oil flows. The rotation speed of the outer ring 52 is slower than the rotation speed of the inner ring 51 . Moreover, in this embodiment, the pair of rolling bearings 50 and 60 are face-to-face. Therefore, no spacer is required between the outer ring 52 and the outer ring 62 . Therefore, no preload is applied to the outer rings 52,62. Therefore, the outer rings 52 and 62 are easily rotated with respect to the bearing housing 2 .

Next, the bearing retainer plate 40 will be described in detail.

FIG. 3 is a schematic plan view showing the bearing retainer plate 40, and the bearing retainer plate 40 is viewed from the bearing hole 22 in the central axis direction. That is, FIG. 3 is obtained along line III-III in FIG. In FIG. 3, the inner diameter of bearing hole 22 is indicated by a dashed line. Also, the outer diameter of the outer side surface 62a of the second bearing 60 is indicated by a dashed line. Arrow R indicates the direction of rotation of shaft 7 . A symbol Z indicates a vertical axis extending upward from the center axis of the shaft 7 .

The bearing retainer plate 40 has a generally annular shape or disk shape. The bearing retainer plate 40 includes an inner peripheral edge 43 and an outer peripheral edge 44 .

With reference to FIG. 2, for example, the diameter of the inner peripheral edge 43 is smaller than the innermost diameter of the outer ring 62 of the second bearing 60 and larger than the outer diameter of the oil slinger member 80 . Also, for example, the diameter of the outer peripheral edge 44 is larger than the inner diameter of the bearing hole 22 . The bearing retainer plate 40 includes a first end surface 41 and a second end surface 42 in the center axis direction. As described above, the first end face 41 defines the end of the bearing hole 22 in the central axis direction. The first end surface 41 faces the outer side surface 62a of the outer ring 62 in the central axis direction. The second end face 42 is located on the opposite side of the first end face 41 .

Referring to FIG. 3, the first end surface 41 includes a guide oil groove 45, a circumferential oil groove 46, and an oil drain surface 47.

The guide oil groove 45 connects the gap between the outer ring 62 and the bearing hole 22 and the circumferential oil groove 46 and guides the oil in this gap to the circumferential oil groove 46 . The guide oil groove 45 extends radially inward from the outside of the outer surface 62a of the outer ring 62 when viewed from the center axis direction. In this embodiment, the guide oil groove 45 has a generally linear shape along the radial direction. In this embodiment, the guide oil groove 45 has a central axis 45a extending in the radial direction. In other embodiments, the guide oil groove 45 does not have to extend radially as long as it extends inward from the outside of the side surface 62a. That is, in other embodiments, the central axis 45a may not extend toward the central axis of the shaft 7. FIG. The guide oil groove 45 extends to the circumferential oil groove 46 and is connected to the circumferential oil groove 46 .

The guide oil groove 45, including the radially outermost portion and the innermost portion, is positioned in a range Ar1 of greater than 0 degrees and less than 90 degrees in the rotational direction R with respect to the vertical axis Z. . In FIG. 3, the cross-hatched area indicates range Ar1. In this embodiment, the central axis 45a is positioned at 45 degrees in the rotation direction R with respect to the vertical axis Z. As shown in FIG. That is, the angle α between the central axis 45a and the vertical axis Z is 45 degrees. In other embodiments, the angle α can be greater than 0 degrees and less than 90 degrees as long as the entire guide oil groove 45 is positioned within the range Ar1.

In a cross section perpendicular to the radial direction, the guide oil groove 45 may have various cross-sectional shapes such as a semicircular shape, a triangular shape, or a square shape. Dimensions such as the width and depth of the guide oil groove 45 are determined according to factors such as the flow rate of the oil supplied to the second bearing 60, for example.

The circumferential oil groove 46 receives oil from the guide oil groove 45 and guides the received oil in the circumferential direction. The circumferential oil groove 46 is positioned inside the guide oil groove 45 in the radial direction. The circumferential oil groove 46 is connected to the guide oil groove 45 . The circumferential oil groove 46 extends along the circumferential direction. In this embodiment, the circumferential oil groove 46 is continuous in the entire circumferential direction and has an annular shape. In this embodiment, the circumferential oil groove 46 is formed continuously with respect to the inner peripheral edge 43 . The circumferential oil groove 46 is integrally formed with the oil drain surface 47 at the lower portion.

Referring to FIG. 2, in this embodiment, the outer diameter of the circumferential oil groove 46 is the same as or substantially the same as the inner diameter of the outer surface 62a of the outer ring 62. In other embodiments, the outer diameter of the circumferential oil groove 46 may be smaller or larger than the inner diameter of the outer surface 62a.

FIG. 4 is a schematic cross-sectional view taken along line IV-IV in FIG. In this embodiment, the depth d1 of the circumferential oil groove 46 is deeper than the depth d2 of the guide oil groove 45. As shown in FIG. In other embodiments, the depth d1 of the circumferential oil groove 46 may be the same as the depth d2 of the guide oil groove 45. In a cross section perpendicular to the circumferential direction, the circumferential oil groove 46 may have various cross-sectional shapes such as a generally rectangular shape. Dimensions such as the width and depth of the circumferential oil groove 46 are determined according to factors such as the flow rate of oil supplied to the second bearing 60, for example.

The oil drain surface 47 is provided in the area below the first end surface 41 . The oil drain surface 47 guides oil below the shaft 7 toward the lower wall 29 . The oil drain surface 47 is formed continuously in the circumferential oil groove 46 . Therefore, the depth of the oil drain surface 47 is the same as the depth d2 of the circumferential oil groove 46 .

Referring to FIG. 3, the oil drain surface 47 has a sector shape coaxial with the shaft 7 when viewed from the central axis direction. For example, the oil drain surface 47 may be provided only within a range of 90 degrees or more and 270 degrees or less with respect to the vertical axis Z in the rotational direction. That is, the oil drain surface 47 can be provided only on the lower half of the bearing retainer plate 40 .

Next, the sidewall 30 will be described in detail.

FIG. 5 is a schematic cross-sectional view taken along line V-V in FIG. 2, looking at the side wall 30 of the bearing housing 2 from the bearing hole 22 in the direction of the central axis. In FIG. 5 only the bearing housing 2 is shown for better understanding. In FIG. 5, the outer diameter of the outer side surface 52a of the first bearing 50 is indicated by a dashed line. Arrow R indicates the direction of rotation of shaft 7 . A symbol Z indicates a vertical axis extending upward from the center axis of the shaft 7 .

As mentioned above, the side wall 30 includes an end surface 31 . In this embodiment, the end surface 31 is continuously formed in the circumferential direction and has a generally annular shape. In other embodiments, part of the end surface 31 may be cut out.

Referring to FIG. 2, the end surface 31 faces the outer side surface 52a of the outer ring 52 in the central axis direction. The inner diameter of the end surface 31 is smaller than the inner diameter of the outer surface 52 a and larger than the diameter of the large diameter portion 7 a of the shaft 7 .

With reference to FIG. 5, the end surface 31 includes a guide oil groove 32. The guide oil groove 32 connects the gap between the outer ring 52 and the bearing hole 22 and the space around the shaft 7 and guides the oil in this gap to the space around the shaft 7 . The guide oil groove 32 extends radially inward from the outside of the outer surface 52a of the outer ring 52 when viewed from the center axis direction. In this embodiment, the guide oil groove 32 has a central axis 32a extending in the radial direction. In other embodiments, the guide oil groove 32 does not have to extend radially as long as it extends inward from the outside of the side surface 52a. That is, in other embodiments, the central axis 32a may not extend toward the central axis of the shaft 7.

The guide oil groove 32, including the radially outermost portion and the innermost portion, is positioned in a range Ar2 of greater than 0 degrees and less than 90 degrees in the rotational direction R with respect to the vertical axis Z. . In FIG. 5, the cross-hatched area indicates range Ar2. In this embodiment, the center axis 32a is positioned at 45 degrees in the rotation direction R with respect to the vertical axis Z. As shown in FIG. That is, the angle β between the central axis 32a and the vertical axis Z is 45 degrees. In other embodiments, the angle α can be greater than 0 degrees and less than 90 degrees as long as the entire guide oil groove 32 is positioned within the range Ar2.

In a cross-section perpendicular to the radial direction, the guide oil groove 32 may have various cross-sectional shapes such as a generally rectangular shape or an arc shape. Dimensions such as the width and depth of the guide oil groove 32 are determined according to factors such as the flow rate of the oil supplied to the first bearing 50, for example. For example, the turbine impeller 8 receives high-temperature exhaust gas, so components around the first bearing 50 are exposed to high temperatures. Therefore, the size of the guide oil groove 32 is larger than the size of the guide oil groove 45 of the bearing retainer plate 40 to provide a higher oil flow rate.

Referring to FIG. 2 , in the turbocharger TC as described above, when oil is supplied from the through hole 25 to the main oil passage 23 , the oil flows from the second oil passage 27 to the outer ring 62 of the second bearing 60 . and the bearing hole 22. Oil is supplied to the space around the shaft 7 from this gap via the outer surface 62a and the inner surface 62b. With such a configuration, oil is supplied to the space between the inner ring 61 and the outer ring 62 .

Referring to FIG. 3 , particularly when the outer surface 62 a of the outer ring 62 contacts the first end surface 41 of the bearing retainer plate 40 , the oil passes through the guide oil groove 45 of the bearing retainer plate 40 and flows around the shaft 7 . supplied to the space. As described above, the guide oil groove 45 is generally positioned in the range Ar1 of greater than 0 degrees and less than 90 degrees with respect to the vertical axis Z in the rotational direction R. Oil is therefore supplied to the space around the shaft 7 in the range Ar1. In this case, both gravity and rotational forces from shaft 7 act downward on the oil. Therefore, the oil quickly flows downward toward the lower wall 29 including the oil drain hole 29a. Therefore, the oil can be efficiently guided in the discharge direction.

Further, referring to FIG. 2 , the gap between the bearing retainer plate 40 near the compressor impeller 9 and the oil slinger member 80 is the space between the side wall 30 near the turbine impeller 8 and the large diameter portion 7 a of the shaft 7 . smaller than Around such a small gap between the bearing restraining plate 40 and the oil slinger member 80, the oil is efficiently guided in the discharge direction, so oil leakage into the gap is reduced. For example, when the distance between the bearing hole 22 and the compressor impeller 9 is shortened for size reduction, oil leakage from the bearing hole 22 to the accommodation space of the compressor impeller 9 may become a problem. According to the configuration as described above, such oil leakage can be reduced.

Further, when oil is supplied from the through hole 25 to the main oil passage 23, the oil flows from the first oil passage 26 into the gap between the outer peripheral surface 52c of the outer ring 52 of the first bearing 50 and the bearing hole 22. flow. From this gap, the oil flows into the space around the shaft 7 via the outer surface 52a and the inner surface 52b. With such a configuration, oil is supplied to the space between the inner ring 51 and the outer ring 52 and the space between the side wall 30 and the large diameter portion 7 a of the shaft 7 .

Referring to FIG. 5 , particularly when the outer surface 52 a of the outer ring 52 contacts the end surface 31 of the side wall 30 , oil is supplied to the space around the shaft 7 through the guide oil groove 32 of the side wall 30 . As described above, the guide oil groove 32 is positioned in the range Ar2, which is greater than 0 degrees and less than 90 degrees with respect to the vertical axis Z, in the rotational direction R as a whole. Oil is therefore supplied to the space around the shaft 7 in the range Ar2. In this case, both gravity and rotational forces from shaft 7 act downward on the oil. Therefore, the oil quickly flows downward toward the lower wall 29 including the oil drain hole 29a. Therefore, the oil can be efficiently guided in the discharge direction.

The turbocharger TC as described above includes a second bearing 60 having a shaft 7, an inner ring 61 attached to the shaft 7, and an outer ring 62 arranged around the inner ring 61, and an outer surface 62a of the outer ring 62. A bearing retainer plate 40 including first end faces 41 facing each other, the first end faces 41 forming guide oil grooves 45 extending inwardly from the outside of the outer surface 62 a of the outer ring 62 when viewed from the direction of the central axis of the shaft 7 . and the entire guide oil groove 45 is positioned within a range Ar1 greater than 0 degrees and less than 90 degrees in the rotational direction R of the shaft 7 with respect to the vertical axis Z extending upward from the central axis of the shaft 7. a plate 40; According to such a configuration, as described above, both gravitational force and rotational force act downward on the oil supplied to the space around the shaft 7 through the guide oil groove 45 . Therefore, the oil quickly flows downward. Normally, the oil drain hole 29a is provided in the lower part of the supercharger TC. Therefore, the oil can be efficiently guided in the discharge direction.

In addition, the supercharger TC includes a bearing housing 2 including a bearing hole 22 that accommodates the second bearing 60, and a compressor impeller 9 that is provided on the shaft 7 outside the bearing hole 22. It is arranged between the bearing hole 22 and the compressor impeller 9 . As described above, for example, when the distance between the bearing hole 22 and the compressor impeller 9 is shortened for size reduction, oil leakage from the bearing hole 22 to the accommodation space of the compressor impeller 9 may become a problem. . According to the configuration as described above, since the oil is efficiently guided in the discharge direction in the vicinity of the gap between the bearing restraining plate 40 and the oil slinger member 80, oil leakage from the bearing hole 22 into the gap is reduced. be. Therefore, oil leakage can be reduced.

Further, in the turbocharger TC, the guide oil groove 45 has a central axis 45a extending along the radial direction of the shaft 7, and the central axis 45a extends in the rotational direction R of the shaft 7 with respect to the vertical axis Z. is located at 45 degrees to . In order to lead the oil downward more quickly, the oil is preferably supplied to a lower position within the range Ar1. However, in order to uniformly supply oil between the inner ring 61 and the outer ring 62 in the circumferential direction, it is desirable that the oil be supplied from a higher position within the range Ar1. According to the above configuration, the oil is supplied around the shaft 7 from the intermediate position of 45 degrees in the range Ar1. Thus, a better balance can be struck between directing the oil downwards quickly and supplying the oil evenly in the circumferential direction.

Similarly, the turbocharger TC includes a first bearing 50 having a shaft 7, an inner ring 51 attached to the shaft 7, and an outer ring 52 arranged around the inner ring 51, and an outer side surface 52a of the outer ring 52. The end surface 31 includes a guide oil groove 32 extending inwardly from the outside of the outer surface 52a of the outer ring 52 when viewed from the center axis direction of the shaft 7. and a side wall 30 located within a range Ar1 larger than 0 degrees and smaller than 90 degrees in the rotational direction R of the shaft 7 with respect to the vertical axis Z extending upward from the center axis of the shaft 7 . According to such a configuration, as described above, both gravitational force and rotational force act downward on the oil supplied to the space around the shaft 7 through the guide oil groove 45 . Therefore, the oil quickly flows downward. Normally, the oil drain hole 29a is provided in the lower part of the supercharger TC. Therefore, the oil can be efficiently guided in the discharge direction.

Further, the turbocharger TC includes a bearing housing 2 including a bearing hole 22 that accommodates the first bearing 50, and a turbine impeller 8 that is provided on the shaft 7 outside the bearing hole 22. Said side wall 30 including the grooved guide oil groove 32 is arranged between the bearing bore 22 and the turbine impeller 8 . The turbine impeller 8 is exposed to hot exhaust gases. According to the above-described configuration including the guide oil groove 32 inclined with respect to the vertical direction in the side wall 30, as described above, the oil can be efficiently guided in the discharge direction, so that the heat-absorbed oil can be quickly discharged into the turbine. It can be discharged from the space near the impeller 8. Therefore, cooling efficiency can be improved.

Further, in the turbocharger TC, the guide oil groove 32 has a central axis 32a extending along the radial direction of the shaft 7, and the central axis 32a extends in the rotational direction R of the shaft 7 with respect to the vertical axis Z. is located at 45 degrees to . Therefore, for the same reasons as above, a better balance can be struck between directing the oil downwards quickly and supplying the oil uniformly in the circumferential direction.

Next, a bearing retainer plate according to another embodiment will be described.

FIG. 6 is a schematic plan view showing a bearing retainer plate 90 according to another embodiment. FIG. 7 is a schematic cross-sectional view taken along line VII-VII in FIG. Referring to FIG. 6, bearing restraining plate 90 differs from bearing restraining plate 40 described above in that projections 48 are included. In other respects, the bearing retainer plate 90 may be the same as the bearing retainer plate 40 .

The projection 48 is located inside the circumferential oil groove 46 in the radial direction. That is, in this embodiment, the circumferential oil groove 46 is separated from the inner peripheral edge 43 by the protrusion 48 . In this embodiment, the protrusions 48 extend continuously along the entire circumference. That is, in this embodiment, the projection 48 has an annular shape. In another embodiment, for example, the protrusion 48 may be provided only within a range of -90 degrees or more and 90 degrees or less in the rotation direction R with respect to the vertical axis Z. That is, in other embodiments, the projections 48 may be provided only on the upper half of the bearing retainer plate 40 .

With reference to FIG. 7, the protrusion 48 protrudes from the circumferential oil groove 46 toward the second bearing 60 in the central axis direction. Regarding the height of the protrusion 48 , for example, the protrusion 48 may be flush with the first end surface 41 .

The turbocharger TC including the bearing restraining plate 90 as described above can achieve substantially the same effects as the turbocharger TC including the bearing restraining plate 40.

In particular, the first end surface 41 of the bearing retainer plate 90 is a circumferential oil groove 46 located inside the guide oil groove 45 in the radial direction and connected to the guide oil groove 45, and extends along the circumferential direction. , a circumferential oil groove 46, and a projection 48 positioned radially inside the circumferential oil groove 46 and projecting in the central axis direction. With such a configuration, the projection 48 can reduce oil leakage into the gap between the bearing restraining plate 90 and the oil slinger member 80 . Therefore, oil leakage can be reduced. Moreover, the projections 48 can efficiently guide the oil to the space between the inner ring 61 and the outer ring 62 . Therefore, the lubrication of the second bearing 60 can be improved.

Next, we will explain the evaluation of oil leakage.

FIG. 8 is a graph showing the evaluation results of oil leakage. In the evaluation of FIG. 8, the following four types of bearing restraining plates were used in the supercharger TC.

Comparative Example 1: The guide oil groove 45 is positioned at 0 degrees in the rotation direction R with respect to the vertical axis Z.
That is, the guide oil groove 45 is positioned on the vertical axis Z.
Other points are the same as those of the bearing restraining plate 40 .
No protrusion is provided.

Comparative Example 2: The guide oil groove 45 is positioned at 0 degrees in the rotation direction R with respect to the vertical axis Z.
That is, the guide oil groove 45 is positioned on the vertical axis Z.
Other points are the same as those of the bearing restraining plate 90 .
A protrusion is provided.

Example 1: The guide oil groove 45 is located at 60 degrees in the rotation direction R with respect to the vertical axis Z.
A protrusion is provided.

Example 2: The guide oil groove 45 is positioned at 45 degrees to the vertical axis Z in the rotational direction R.
A protrusion is provided.

The following evaluations were carried out using each of the four types of bearing retainer plates.

The shaft 7 was rotated at multiple rotation speeds. Oil was supplied from the oil pump to the supercharger TC at a plurality of flow rates at each of a plurality of rotational speeds. The flow rate was measured when oil leakage from the gap between the bearing retainer plate and the oil slinger was confirmed. Regarding the flow rate when oil leakage was confirmed at each rotational speed, the ratio of the flow rate of each of the four types of bearing restraining plates to the flow rate of Comparative Example 1 was calculated. The calculated value is indicated as "improvement rate" on the vertical axis of FIG. When the improvement rate is greater than 1, oil leakage is reduced relative to Comparative Example 1. In contrast, when the improvement rate is less than 1, oil leakage increases relative to Comparative Example 1. The solid line indicates the percent improvement of Comparative Example 1 over Comparative Example 1 and therefore always indicates 1. A two-dot chain line indicates the improvement rate of Comparative Example 2 with respect to Comparative Example 1. The dashed line indicates the improvement rate of Example 1 with respect to Comparative Example 1. A dashed-dotted line indicates the improvement rate of Example 2 with respect to Comparative Example 1.

　Lubrication can be a problem in the high rpm range, so oil leakage can also be a problem in the high rpm range. Therefore, attention is paid to the improvement rate in the high rotational speed region.

By comparing Comparative Examples 1 and 2, it can be seen whether or not the projections contribute to the reduction of oil leakage. As can be clearly seen from FIG. 8, the improvement rate of Comparative Example 2 is greater than one. Therefore, it can be seen that the projection contributes to the reduction of oil leakage.

By comparing Comparative Example 2, Example 1, and Example 2, it can be seen whether or not inclining the guide oil groove 45 in the rotational direction contributes to reducing oil leakage. As can be clearly seen from FIG. 8, the improvement rate of Example 1 is higher than the improvement rate of Comparative Example 2. Moreover, the improvement rate of Example 2 is higher than the improvement rate of Comparative Example 2. Therefore, it can be seen that inclining the guide oil groove 45 in the rotational direction contributes to the reduction of oil leakage. Further, the improvement rate of Example 2 is substantially the same as the improvement rate of Example 1. Therefore, even if the guide oil groove 45 is inclined by more than 45 degrees, the improvement rate is substantially the same as when the guide oil groove 45 is inclined by 45 degrees. Therefore, it can be seen that the oil leakage can be sufficiently reduced by inclining the guide oil groove 45 by 45 degrees.

Although the embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to the above embodiments. It is clear that a person skilled in the art can conceive of various modifications or modifications within the scope of the claims, and it is understood that these also belong to the technical scope of the present disclosure. be done.

For example, in the above embodiment, the turbocharger TC includes two rolling bearings 50, 60 in the bearing hole 22, spaced apart in the central axis direction. However, in other embodiments the supercharger TC may comprise more than two rolling bearings.

In the above embodiment, the outer rings 52, 62 are rotatable with respect to the bearing housing 2. However, in other embodiments the outer rings 52 , 62 may be rotationally fixed with respect to the bearing housing 2 .

In the above embodiment, the pair of rolling bearings 50, 60 are angular bearings and face-to-face. However, in other embodiments, the rolling bearings may be rolling bearings other than angular bearings (eg, deep groove ball bearings or self-aligning ball bearings). Also, the pair of rolling bearings 50 and 60 may be a back-to-back combination.

Since the present disclosure can reduce oil leakage into the intake and promote cleaner exhaust gas, the United Nations Sustainable Development Goals (SDGs) Goal 13 "Climate change and its impacts It will be possible to contribute to "taking emergency measures to confront".

2 bearing housing 7 shaft 8 turbine impeller 9 compressor impeller 22 bearing hole 30 side wall (restricting member)
31 end face 32 guide oil groove 32a central axis 40 bearing restraining plate (restricting member)
41 First end surface 45 Guide oil groove 45a Center axis 46 Circumferential oil groove 48 Protrusion 50 First bearing (rolling bearing)
51 inner ring 52 outer ring 52a outer surface (side surface)
60 Second bearing (rolling bearing)
61 inner ring 62 outer ring 62a outer surface (side surface)
90 bearing restraining plate (restricting member)
R Direction of rotation TC Turbocharger Z Vertical axis

Claims (5)

1. a shaft;
   a rolling bearing having an inner ring attached to the shaft and an outer ring arranged around the inner ring;
   A regulating member including an end surface facing a side surface of the outer ring, the end surface including a guide oil groove extending inwardly from the outside of the side surface of the outer ring when viewed from the axial direction of the shaft. a regulating member in which the entire oil groove is positioned in a range of greater than 0 degrees and less than 90 degrees in the rotational direction of the shaft with respect to a vertical axis extending upward from the central axis of the shaft;
   A supercharger.
2. a housing including a bearing hole that accommodates the rolling bearing;
   a compressor impeller provided on the shaft outside the bearing hole;
   further comprising
   2. The turbocharger according to claim 1, wherein said restricting member is arranged between said bearing hole and said compressor impeller.
3. The end surface of the regulating member is
   a circumferential oil groove located inside the guide oil groove in the radial direction of the shaft and connected to the guide oil groove, the oil groove extending along the circumferential direction of the shaft; ,
   a projection located inside the circumferential oil groove in the radial direction of the shaft and protruding in the direction of the central axis of the shaft;
   3. A supercharger according to claim 2, comprising:
4. a housing including a bearing hole that accommodates the rolling bearing;
   a turbine impeller mounted on the shaft outside the bearing hole;
   further comprising
   The turbocharger according to claim 1, wherein said regulating member is arranged between said bearing hole and said turbine impeller.
5. The guide oil groove has a central axis extending along the radial direction of the shaft,
   The supercharger according to any one of claims 1 to 4, wherein the central axis of the guide oil groove is positioned at 45 degrees with respect to the vertical axis in the direction of rotation of the shaft.

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