WO2022209131A1

WO2022209131A1 - Bearing and supercharger

Info

Publication number: WO2022209131A1
Application number: PCT/JP2022/000912
Authority: WO
Inventors: 英之小島; 朗弘上田
Original assignee: 株式会社Ihi
Priority date: 2021-04-02
Filing date: 2022-01-13
Publication date: 2022-10-06

Abstract

A bearing 13 comprising: a plurality of oil supply grooves 39 provided on a radial bearing surface 13d and extending in the axial direction of a main body 13a; and a plurality of chamfered sections 49-1–49-4 that are provided between the radial bearing surface 13d and a thrust bearing surface 13i, are mutually partitioned in the circumferential direction by the plurality of oil supply grooves 39, and have an area for each chamfered section 49-1–49-4 that is greater than half of the area of the oil supply grooves 39, when viewed from the axial direction.

Description

bearings and turbochargers

The present disclosure relates to bearings and superchargers. This application claims the benefit of priority based on Japanese Patent Application No. 2021-63731 filed on April 2, 2021, the content of which is incorporated herein by reference.

A variety of devices use bearings to support shafts. For example, Patent Literature 1 discloses a turbocharger that includes bearings that support a shaft. Lubricating oil is supplied to bearings used in turbochargers and the like.

Japanese Patent No. 5807436

As a bearing that supports a shaft, there is a bearing (that is, a thrust bearing) that has a thrust bearing surface that supports a member axially adjacent to the bearing. The lubricating oil supplied to the inside of the bearing is supplied to the thrust bearing surface of the bearing as the shaft rotates. A thrust load (that is, a load in the thrust direction) is supported by the oil film pressure of lubricating oil supplied to the thrust bearing surface. In such a bearing, it is desired to appropriately supply lubricating oil over the entire circumference of the thrust bearing surface.

An object of the present disclosure is to provide a bearing and a turbocharger that can appropriately supply lubricating oil over the entire circumference of the thrust bearing surface.

In order to solve the above problems, the bearing of the present disclosure includes an annular main body through which the shaft is inserted, a radial bearing surface provided on the inner peripheral surface of the main body and facing the shaft in the radial direction, and a radial bearing surface provided on the radial bearing surface. A plurality of oil supply grooves extending in the axial direction of the main body, a thrust bearing surface provided on the end surface of the main body, and a thrust bearing surface provided on the thrust bearing surface spaced apart from each other in the circumferential direction of the main body and extending in the rotational direction of the shaft. a partition wall provided on the thrust bearing surface and arranged between the plurality of tapered portions and the outer peripheral edge of the thrust bearing surface; and an oil supply groove and the outer peripheral edge provided on the thrust bearing surface. and a plurality of chamfered portions provided between the radial bearing surface and the thrust bearing surface and partitioned from each other in the circumferential direction by a plurality of oil supply grooves, when viewed from the axial direction and a plurality of chamfers, each of which has an area larger than half the area of the oil supply groove.

The oil drain groove may have an inclined portion on the forward side in the direction of rotation.

The bearing further includes a non-through groove provided in the tapered portion, the inner diameter end of the non-through groove being connected to the chamfered portion, and the outer diameter end of the non-through groove being positioned within the tapered portion. may

The non-through groove may be located on the rear side in the rotational direction with respect to the center of the tapered portion in the circumferential direction.

In order to solve the above problems, the turbocharger of the present disclosure includes the above bearings.

According to the present disclosure, lubricating oil can be appropriately supplied over the entire circumference of the thrust bearing surface.

1 is a schematic cross-sectional view of a turbocharger according to an embodiment of the present disclosure; FIG. FIG. 2 is an extraction diagram of the dashed-dotted line portion of FIG. 3 is a front view of a thrust bearing surface of a bearing according to an embodiment of the present disclosure; FIG. FIG. 4 is a cross-sectional view showing the AA cross section of FIG. FIG. 5 is an enlarged cross-sectional view of a thrust bearing surface side end of a bearing according to an embodiment of the present disclosure. FIG. 6 is a diagram showing the cross-sectional shape of the thrust bearing surface of the first modified example. FIG. 7 is a front view of the thrust bearing surface of the second modified example.

An embodiment of the present disclosure will be described below with reference to the accompanying drawings. Dimensions, materials, and other specific numerical values shown in the 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 of the turbocharger TC. In FIG. 1, the direction of arrow U is the vertically upward direction, and the direction of arrow D is the vertically downward direction. In the following description, the direction of arrow L shown in FIG. 1 is assumed to be the left side of turbocharger TC. The direction of the arrow R shown in FIG. 1 will be described as the right side of the supercharger TC. As shown in FIG. 1 , the supercharger TC includes a supercharger body 1 . The turbocharger body 1 includes a bearing housing 3, a turbine housing 5, and a compressor housing 7. The turbine housing 5 is connected to the left side of the bearing housing 3 by a fastening mechanism 9 . The compressor housing 7 is connected to the right side of the bearing housing 3 by fastening bolts 11 .

A protrusion 3 a is provided on the outer peripheral surface of the bearing housing 3 . The protrusion 3 a is provided near the turbine housing 5 . The protrusion 3a protrudes radially. A protrusion 5 a is provided on the outer peripheral surface of the turbine housing 5 . A protrusion 5 a is provided near the bearing housing 3 . The protrusion 5a protrudes radially. The bearing housing 3 and the turbine housing 5 are band-fastened by a fastening mechanism 9 . The fastening mechanism 9 is, for example, a G coupling. The fastening mechanism 9 clamps the protrusion 3a and the protrusion 5a.

A bearing hole 3 b is formed in the bearing housing 3 . The bearing hole 3b penetrates the bearing housing 3 in the lateral direction of the supercharger TC. A bearing 13 is arranged in the bearing hole 3b. Bearing 13 is a semi-floating bearing. However, the bearing 13 may be a bearing other than the semi-floating bearing, as will be described later. Bearing 13 rotatably supports shaft 15 . A turbine wheel 17 is provided at the left end of the shaft 15 . The turbine wheel 17 is rotatably housed in the turbine housing 5 . A compressor impeller 19 is provided at the right end of the shaft 15 . A compressor impeller 19 is rotatably housed in the compressor housing 7 . In this disclosure, "axial", "radial" and "circumferential" of bearing 13, shaft 15, turbine wheel 17 and compressor impeller 19 are simply referred to as "axial", "radial" and "circumferential" respectively. ” can be called. A lower portion of the bearing housing 3 is formed with an oil drain port 3c through which lubricating oil splashing from the bearing 13 is discharged.

An intake port 21 is formed in the compressor housing 7 . The intake port 21 opens on the right side of the supercharger TC. The intake port 21 is connected to an air cleaner (not shown). A diffuser flow path 23 is formed by the surfaces of the bearing housing 3 and the compressor housing 7 . The diffuser channel 23 pressurizes the air. The diffuser flow path 23 is formed in an annular shape. The diffuser flow path 23 communicates with the intake port 21 via the compressor impeller 19 on the radially inner side.

A compressor scroll flow path 25 is provided in the compressor housing 7 . The compressor scroll channel 25 is located radially outside the diffuser channel 23, for example. The compressor scroll channel 25 communicates with the intake port of the engine (not shown) and the diffuser channel 23 . When the compressor impeller 19 rotates, air is drawn into the compressor housing 7 through the intake port 21 . Intake air is pressurized and accelerated while flowing between the blades of the compressor impeller 19 . The pressurized and accelerated air is further pressurized in the diffuser passage 23 and the compressor scroll passage 25 . The pressurized air is directed to the engine intake.

A discharge port 27 is formed in the turbine housing 5 . The discharge port 27 opens on the left side of the supercharger TC. The discharge port 27 is connected to an exhaust gas purification device (not shown). A communication passage 29 and a turbine scroll passage 31 are formed in the turbine housing 5 . The turbine scroll passage 31 is located radially outside the communication passage 29, for example. The turbine scroll passage 31 communicates with a gas inlet (not shown). Exhaust gas discharged from an exhaust manifold of an engine (not shown) is guided to the gas inlet. The communication passage 29 connects the turbine scroll passage 31 and the discharge port 27 via the turbine wheel 17 . The exhaust gas guided from the gas inlet to the turbine scroll passage 31 is further guided to the discharge port 27 via the communication passage 29 and the turbine wheel 17 . The exhaust gas guided to the discharge port 27 rotates the turbine wheel 17 in the flow process.

The rotational force of the turbine wheel 17 is transmitted to the compressor impeller 19 via the shaft 15. As the compressor impeller 19 rotates, the air is pressurized as described above. Air is thus directed to the intake of the engine.

FIG. 2 is a diagram extracting the dashed-dotted line portion of FIG. As shown in FIG. 2, a bearing structure BS is provided inside the bearing housing 3 . Bearing structure BS includes bearing hole 3 b , bearing 13 , and shaft 15 .

An oil passage 3d is formed in the bearing housing 3. Lubricating oil is supplied to the oil passage 3d. The oil passage 3d opens (communicates) with the bearing hole 3b. The oil passage 3d guides the lubricating oil to the bearing hole 3b. The lubricating oil flows into the bearing hole 3b from the oil passage 3d.

A bearing 13 is arranged in the bearing hole 3b. The bearing 13 has an annular body 13a. An insertion hole 13b is formed in the main body 13a. The insertion hole 13b axially penetrates the main body 13a. The axial direction intersects (specifically, is perpendicular to) the vertical direction. The shaft 15 is inserted through the insertion hole 13b. The main body 13a extends in a direction intersecting (more specifically, perpendicular to) the vertical direction.

Two radial bearing surfaces 13d and 13e are formed on the inner peripheral surface 13c of the main body 13a (insertion hole 13b). The two

radial bearing surfaces

13d, 13e are axially spaced apart. An oil hole 13f is formed in the main body 13a. The oil hole 13f penetrates from the inner peripheral surface 13c of the main body 13a to the outer peripheral surface 13g. The oil hole 13f is arranged between the two

radial bearing surfaces

13d, 13e. The oil hole 13f faces the opening of the oil passage 3d in the radial direction.

The lubricating oil flows from the outer peripheral surface 13g of the main body 13a to the inner peripheral surface 13c through the oil holes 13f. The lubricating oil that has flowed into the inner peripheral surface 13c of the main body 13a moves between the inner peripheral surface 13c and the shaft 15 along the circumferential direction. Further, the lubricating oil that has flowed into the inner peripheral surface 13c of the main body 13a moves between the inner peripheral surface 13c and the shaft 15 along the axial direction (horizontal direction in FIG. 2). Lubricating oil is supplied to the gap between the shaft 15 and the two

radial bearing surfaces

13d, 13e. An oil film is formed by lubricating oil supplied to the gap between the shaft 15 and the two radial bearing surfaces 13d and 13e. The shaft 15 is supported by the oil film pressure of the lubricating oil. The two radial bearing surfaces 13d and 13e receive the radial load of the shaft 15 (that is, the load in the radial direction).

A through hole 13h is formed in the main body 13a. The through hole 13h penetrates from the inner peripheral surface 13c of the main body 13a to the outer peripheral surface 13g. The through hole 13h is arranged between the two

radial bearing surfaces

13d, 13e. The through hole 13h is arranged on the opposite side of the main body 13a to the oil hole 13f. However, the position of the through hole 13h is not limited to this, and the position of the through hole 13h may be different from the position of the oil hole 13f in the circumferential direction.

A pin hole 3e is formed in the bearing housing 3. The pin hole 3e is formed at a position facing the through hole 13h in the bearing hole 3b. The pin hole 3e penetrates the wall forming the bearing hole 3b. The pin hole 3e connects the inner space and the outer space of the bearing hole 3b. A positioning pin 33 is inserted through the pin hole 3e. Specifically, the positioning pin 33 is press-fitted into the pin hole 3e. The tip of the positioning pin 33 is inserted through the through hole 13h of the main body 13a. The positioning pin 33 regulates the rotational and axial movement of the body 13a.

The shaft 15 includes a large diameter portion 15a, a medium diameter portion 15b, and a small diameter portion 15c. The large diameter portion 15a is positioned closer to the turbine wheel 17 (see FIG. 1) than the main body 13a. The large diameter portion 15a has a cylindrical shape. The outer diameter of the large diameter portion 15a is larger than the inner diameter of the inner peripheral surface 13c (radial bearing surface 13d) of the main body 13a. The outer diameter of the large diameter portion 15a is larger than the outer diameter of the outer peripheral surface 13g of the main body 13a. However, the outer diameter of the large diameter portion 15a may be equal to or smaller than the outer diameter of the outer peripheral surface 13g of the main body 13a. The large diameter portion 15a faces the main body 13a in the axial direction. The large diameter portion 15a has a constant outer diameter. However, the outer diameter of the large diameter portion 15a may not be constant.

The medium diameter portion 15b is positioned closer to the compressor impeller 19 (see FIG. 1) than the large diameter portion 15a. The medium diameter portion 15b has a cylindrical shape. The medium diameter portion 15b is inserted through the insertion hole 13b of the main body 13a. Therefore, the medium diameter portion 15b faces the inner peripheral surface 13c (

radial bearing surfaces

13d, 13e) of the insertion hole 13b in the radial direction. The medium diameter portion 15b has an outer diameter smaller than that of the large diameter portion 15a. The outer diameter of the medium diameter portion 15b is smaller than the inner diameter of the radial bearing surfaces 13d and 13e of the main body 13a. The medium diameter portion 15b has a constant outer diameter. However, the outer diameter of the medium diameter portion 15b may not be constant.

The small diameter portion 15c is positioned closer to the compressor impeller 19 (see FIG. 1) than the medium diameter portion 15b (main body 13a). The small diameter portion 15c has a cylindrical shape. The small diameter portion 15c has an outer diameter smaller than that of the medium diameter portion 15b. The small diameter portion 15c has a constant outer diameter. However, the outer diameter of the small diameter portion 15c may not be constant.

An annular oil draining member 35 is attached to the small diameter portion 15c. The oil slinger member 35 scatters the lubricating oil flowing toward the compressor impeller 19 along the shaft 15 radially outward. That is, the oil slinger member 35 suppresses leakage of lubricating oil to the compressor impeller 19 side.

The oil slinger member 35 has an outer diameter larger than that of the intermediate diameter portion 15b. The outer diameter of the oil slinger 35 is larger than the inner diameter of the inner peripheral surface 13c (radial bearing surface 13e) of the main body 13a. The outer diameter of the oil slinger 35 is smaller than the outer diameter of the outer peripheral surface 13g of the main body 13a. However, the outer diameter of the oil slinger 35 may be equal to or greater than the outer diameter of the outer peripheral surface 13g of the main body 13a. The oil slinger member 35 faces the main body 13a in the axial direction.

The main body 13a is axially sandwiched between the oil draining member 35 and the large diameter portion 15a.

Thrust bearing surfaces

13i and 13j are provided on the axial end surfaces of the main body 13a. The thrust bearing surface 13i is provided on the end surface of the main body 13a near the turbine wheel 17 (see FIG. 1). A thrust bearing surface 13j is provided on the end surface of the main body 13a near the compressor impeller 19 (see FIG. 1). Lubricating oil is supplied to the thrust bearing surface 13i through the inner peripheral surface 13c. As a result, lubricating oil is supplied to the gap between the thrust bearing surface 13i and the large diameter portion 15a. An oil film is formed by the lubricating oil supplied to the gap between the thrust bearing surface 13i and the large diameter portion 15a. Lubricating oil is supplied to the thrust bearing surface 13j through the inner peripheral surface 13c. As a result, the lubricating oil is supplied to the gap between the thrust bearing surface 13j and the oil slinger member 35. As shown in FIG. Lubricating oil supplied to the gap between the thrust bearing surface 13j and the oil slinger 35 forms an oil film.

When the shaft 15 moves in the axial direction (left side in FIG. 2), the load in the thrust direction (axial direction) is supported by the oil film pressure of the lubricating oil between the thrust bearing surface 13i and the large diameter portion 15a. When the shaft 15 moves in the axial direction (right side in FIG. 2), the oil film pressure of the lubricating oil between the thrust bearing surface 13j and the slinger member 35 supports the load in the thrust direction (axial direction). Thus, the two

thrust bearing surfaces

13i, 13j are subjected to thrust loads.

Damper portions

13k and 13m are formed on the outer peripheral surface 13g of the main body 13a. The

damper portions

13k and 13m are axially separated from each other. The

damper portions

13k and 13m are formed at both ends in the axial direction of the outer peripheral surface 13g. The outer diameters of the

damper portions

13k and 13m are larger than the outer diameters of other portions of the outer peripheral surface 13g. Lubricating oil is supplied to the gap between the

damper portions

13k, 13m and the inner peripheral surface 3f of the bearing hole 3b. An oil film is formed by lubricating oil supplied to the gap between the

damper portions

13k and 13m and the inner peripheral surface 3f of the bearing hole 3b. Vibration of the shaft 15 is suppressed by the oil film pressure of the lubricating oil.

FIG. 3 is a front view showing the thrust bearing surface 13i of the bearing 13 according to this embodiment. FIG. 3 is a view of the thrust bearing surface 13i viewed from the left side in FIG. The shape of the thrust bearing surface 13j is substantially the same as that of the thrust bearing surface 13i. Therefore, description of the shape of the thrust bearing surface 13j is omitted. The shape of the radial bearing surface 13e is substantially the same as the shape of the radial bearing surface 13d. Therefore, the description of the shape of the radial bearing surface 13e is omitted.

As shown in FIG. 3, a plurality of circular arc surfaces 37 and a plurality of oil supply grooves 39 are formed on the radial bearing surface 13d. In the example of FIG. 3, the radial bearing surface 13d has four arcuate surfaces 37 and four oil supply grooves 39. In the example of FIG. However, the number of arcuate surfaces 37 and oil supply grooves 39 is not limited to this, and may be other than four.

The plurality of arcuate surfaces 37 are radially separated from the shaft 15 (medium diameter portion 15b). A plurality of arcuate surfaces 37 are arranged side by side in the circumferential direction. The positions of the centers of curvature of the plurality of circular arc surfaces 37 are different from the central axis of the insertion hole 13b. The positions of the centers of curvature of the plurality of arcuate surfaces 37 are different from each other. The positions of the centers of curvature of the plurality of arcuate surfaces 37 are located on the same circle around the central axis of the insertion hole 13b. However, the positions of the centers of curvature of the plurality of circular arc surfaces 37 do not have to be positioned on the same circle. Also, the positions of the centers of curvature of the plurality of circular arc surfaces 37 may be at the same position as the central axis of the insertion hole 13b.

An oil supply groove 39 is formed between two circular arc surfaces 37 adjacent in the circumferential direction. The oil supply grooves 39 are formed in the radial bearing surface 13d at intervals in the circumferential direction. In this embodiment, four oil supply grooves 39 are provided in the circumferential direction. The oil supply groove 39 extends in the axial direction. The cross-sectional shape of the oil supply groove 39 (that is, the cross-sectional shape perpendicular to the axial direction) is a shape (specifically, a triangular shape) in which the width in the circumferential direction tapers toward the radially outer side. However, the cross-sectional shape of the oil supply groove 39 may be a polygonal shape (for example, a rectangular shape) other than a triangular shape, a semicircular shape, or the like.

The oil supply groove 39 extends from the end of the radial bearing surface 13d on the side where the two radial bearing surfaces 13d and 13e (see FIG. 2) are close to the end on the side where the two radial bearing surfaces 13d and 13e are separated. extended. The oil supply groove 39 opens to the thrust bearing surface 13i (that is, the axial end surface of the main body 13a). The oil supply groove 39 allows lubricating oil to flow. The oil supply groove 39 supplies lubricating oil to the radial bearing surface 13d. Further, the oil supply groove 39 supplies lubricating oil to the thrust bearing surface 13i.

The lubricating oil between the shaft 15 and the radial bearing surface 13d moves in the rotation direction RD as the shaft 15 rotates. At this time, the lubricating oil is compressed between the arc surface 37 of the radial bearing surface 13 d and the shaft 15 . The compressed lubricating oil presses the shaft 15 radially inward (wedge effect). Thereby, the radial load is supported by the radial bearing surface 13d.

As shown in FIG. 3, the thrust bearing surface 13i includes a plurality of tapered portions 41 (specifically, tapered portions 41-1, 41-2, 41-3, and 41-4) and a plurality of land portions 43. , a plurality of oil drain grooves 45, a partition wall portion 47, and a chamfered portion 49 are formed. The tapered portion 41 is a portion of the thrust bearing surface 13i that is recessed with respect to a plane orthogonal to the axial direction. The land portion 43 is a planar portion formed between a pair of tapered portions 41 adjacent in the circumferential direction and perpendicular to the axial direction. The land portion 43 is located on the side where the pair of radial bearing surfaces 13d and 13e are separated from the tapered portion 41. As shown in FIG. That is, the tapered portion 41 is a portion that is recessed with respect to the land portion 43 . In the example of FIG. 3, the thrust bearing surface 13i has four tapered portions 41. As shown in FIG. However, it is not limited to this, and the number of tapered portions 41 may be other than four.

The tapered portion 41 is separated from the outer peripheral edge of the thrust bearing surface 13i. A partition wall portion 47 exists radially outside the taper portion 41 on the thrust bearing surface 13i. The partition wall portion 47 has a surface that is at the same axial position as the land portion 43 . Here, "equal" includes the case of being completely equal and the case of being deviated from the case of being completely equal within the range of allowable error (processing accuracy, assembly error, etc.). The partition wall portion 47 is located on the side where the pair of radial bearing surfaces 13d and 13e are separated from the tapered portion 41 . That is, the tapered portion 41 is a portion that is recessed with respect to the partition wall portion 47 . The partition wall portion 47 is arranged between the tapered portion 41 and the outer peripheral edge of the thrust bearing surface 13i. The partition wall portion 47 restricts movement of the lubricating oil radially outward from the tapered portion 41 . This makes it easier to maintain the required amount of oil and hydraulic pressure for the thrust bearing surface 13i. The tapered portion 41 extends in the circumferential direction. The length of the tapered portion 41 in the radial direction is constant. However, the radial length of the tapered portion 41 may not be constant.

The plurality of tapered portions 41 are provided at intervals in the circumferential direction. The tapered portions 41-1, 41-2, 41-3, and 41-4 are arranged in this order at regular intervals. The tapered portions 41-1, 41-2, 41-3, 41-4 have the same shape. However, the tapered portions 41-1, 41-2, 41-3, and 41-4 may be arranged at uneven intervals. The tapered portions 41-1 and 41-4 are formed on the vertical upper side (specifically, the vertical upper half) of the thrust bearing surface 13i. The tapered portion 41-4 is closer to the vertical uppermost portion of the thrust bearing surface 13i than the tapered portion 41-1. The tapered portions 41-2 and 41-3 are formed on the vertically lower side (specifically, the vertically lower half) of the thrust bearing surface 13i. The tapered portion 41-2 is closer to the lowermost portion in the vertical direction of the thrust bearing surface 13i than the tapered portion 41-3.

The oil drain groove 45 communicates with the oil supply groove 39 . One oil drain groove 45 is formed in each of the tapered portions 41-1, 41-2, 41-3, 41-4. That is, in this embodiment, four oil drain grooves 45 are provided in the circumferential direction of the thrust bearing surface 13i. The oil drain groove 45 extends radially. However, the oil drain groove 45 may extend in a direction that is inclined with respect to the radial direction. The oil drain groove 45 is a through groove radially penetrating the thrust bearing surface 13i. The oil drain groove 45 is formed at the rear end of the tapered portion 41 in the rotational direction RD. In this embodiment, the oil drain groove 45 is positioned between the land portion 43 and the tapered portion 41 .

FIG. 4 is a sectional view showing the AA section of FIG. AA cross section in FIG. 3 is a cross section along the circumferential direction passing through the tapered portion 41-2. That is, FIG. 4 shows the cross-sectional shape along the circumferential direction of the tapered portion 41-2.

As shown in FIG. 4, the tapered portion 41 becomes shallower as it progresses in the circumferential direction (specifically, forward in the rotational direction RD). The tapered portion 41 is inclined with respect to the circumferential direction at a constant inclination angle. However, the inclination angle of the tapered portion 41 may vary depending on the position in the circumferential direction. The lubricating oil supplied to the thrust bearing surface 13i moves in the rotational direction RD as the shaft 15 rotates. At this time, the lubricating oil is compressed between the tapered portion 41 of the thrust bearing surface 13i and the large diameter portion 15a (see FIG. 2). The compressed lubricating oil presses the large diameter portion 15a in the axial direction (thrust direction) (wedge effect). As a result, oil film pressure is likely to be generated, and the load capacity in the thrust direction by the thrust bearing surface 13i is increased.

As shown in FIGS. 3 and 4, the oil drain groove 45 connects the oil supply groove 39 and the outer peripheral edge of the thrust bearing surface 13i. The lubricating oil supplied to the thrust bearing surface 13i passes through the oil drain groove 45 and flows through an opening 45a on the outer peripheral edge side of the thrust bearing surface 13i (hereinafter also referred to as an outer peripheral edge side opening 45a of the oil drain groove 45). called). The oil drain groove 45 promotes the flow of the lubricating oil on the thrust bearing surface 13i by discharging the lubricating oil supplied to the thrust bearing surface 13i from the thrust bearing surface 13i. As a result, the temperature rise of the oil film formed on the thrust bearing surface 13i is suppressed, and the decrease in viscosity accompanying the temperature rise is suppressed. Therefore, a decrease in load capacity in the thrust direction due to the thrust bearing surface 13i is suppressed.

The shape of the cross section of the oil drain groove 45 (that is, the shape of the cross section perpendicular to the extending direction of the oil drain groove 45) is semicircular. However, the shape of the cross section of the oil drain groove 45 may be an arc shape, an elliptical arc shape, a rectangular shape, a polygonal shape (for example, a triangular shape), or the like.

In the examples of FIGS. 3 and 4, the oil drain groove 45 is located adjacent to the front side of the land portion 43 in the rotation direction RD. Also, the tapered portion 41 is positioned adjacent to the rear side of the oil drain groove 45 in the rotational direction RD. However, it is not limited to this, and the oil drain groove 45 may be separated from the land portion 43 forward in the rotation direction RD. For example, the oil drain groove 45 is arranged on the rear side in the rotational direction RD with respect to the center of the tapered portion 41 in the circumferential direction. The lubricating oil flows in the rotation direction RD as the shaft 15 rotates. Therefore, by arranging the oil drain groove 45 on the rear side in the rotational direction RD with respect to the center in the circumferential direction of the tapered portion 41, more lubricating oil can be supplied to the tapered portion 41 than in the case of arranging it on the front side in the rotational direction RD. can supply. As a result, it is possible to easily maintain the necessary amount of oil and hydraulic pressure for the thrust bearing surface 13i.

The chamfered portion 49 is formed between the radial bearing surface 13d and the thrust bearing surface 13i. The chamfered portion 49 is formed along the entire circumference of the main body 13a. In this embodiment, the chamfered portion 49 is chamfered. However, it is not limited to this, and the chamfered portion 49 may be R-chamfered.

As shown in FIG. 3, when the thrust bearing surface 13i is viewed in the axial direction, the chamfered portion 49 is formed by the four oil supply grooves 39 and the four oil discharge grooves 45 in the circumferential direction. -2, 49-3, 49-4. The tapered portion 41-1 is adjacent to the chamfered portion 49-1 radially outwardly. The tapered portion 41-2 is adjacent to the chamfered portion 49-2 radially outwardly. The tapered portion 41-3 is adjacent to the chamfered portion 49-3 radially outwardly. The tapered portion 41-4 is adjacent to the chamfered portion 49-4 radially outwardly. When the thrust bearing surface 13i is viewed in the axial direction, the area of the chamfered portion 49 is larger than the area of the oil supply groove 39 .

As shown in FIG. 3, when the thrust bearing surface 13i is viewed in the axial direction, a pair of chamfered portions 49 (for example, chamfered portions 49-2 and 49-3) are provided on both sides of the oil supply groove 39 in the circumferential direction. be done. The lubricating oil that has flowed through the oil supply groove 39 branches in the circumferential direction at the chamfered portion 49 . Specifically, the lubricating oil circulating on the front side of the oil supply groove 39 in the rotational direction RD reaches the chamfered portion 49 (for example, the chamfered portion 49-2) adjacent to the front side of the oil supply groove 39 in the rotational direction RD. Further, the lubricating oil that flows in the rear side of the oil supply groove 39 in the rotation direction RD reaches the chamfered portion 49 (for example, the chamfered portion 49-3) adjacent to the rear side of the oil supply groove 39 in the rotation direction RD. Here, the area of the oil supply groove 39 on the front side in the rotation direction RD, that is, the half area of the oil supply groove 39 is the chamfered portion 49 adjacent to the oil supply groove 39 on the front side in the rotation direction RD (for example, the chamfered portion 49-2). ). Further, the area of the oil groove 39 on the rear side in the rotational direction RD, that is, the half area of the oil groove 39 is the chamfered portion 49 (for example, the chamfered portion 49-3) adjacent to the oil groove 39 on the rear side in the rotational direction RD. smaller than the area of In other words, the area of each chamfered portion 49 is larger than half the area of the oil supply groove 39 . Thus, the area of one chamfered portion 49 partitioned in the circumferential direction by the plurality of oil grooves 39 is larger than half the area of the oil groove 39 .

If the area of each chamfered portion 49 is smaller than half the area of the oil supply groove 39 , most of the lubricating oil flowing through the oil supply groove 39 flows into the oil drain groove 45 . becomes difficult to flow. On the other hand, when the area of each chamfered portion 49 is larger than half the area of the oil groove 39, compared to the case where the area of each chamfered portion 49 is smaller than half the area of the oil groove 39, the oil groove 39 extends from the chamfered portion. The lubricating oil can easily flow to the taper portion 41 via 49 . As a result, lubricating oil can be appropriately supplied to the entire circumference of the thrust bearing surface 13i, and wear of the thrust bearing surface 13i can be prevented.

FIG. 5 is an enlarged cross-sectional view of the end of the bearing 13 on the thrust bearing surface 13i side according to the embodiment of the present disclosure. FIG. 5 shows a cross section including the central axis of bearing 13 . As shown in FIG. 5 , the radial width of chamfered portion 49 is greater than the radial width of oil supply groove 39 . The channel cross-sectional area S<b>1 of the chamfered portion 49 is larger than the channel cross-sectional area S<b>2 of the oil supply groove 39 . This makes it easier to supply the lubricating oil to the tapered portion 41 than when the channel cross-sectional area S<b>1 of the chamfered portion 49 is smaller than the channel cross-sectional area S<b>2 of the oil supply groove 39 .

As described above, in the bearing 13 according to the present embodiment, the chamfered portion 49-1 having an area larger than half the area of the oil supply groove 39 is provided between the

radial bearing surfaces

13d, 13e and the thrust bearing surfaces 13i, 13j. , 49-2, 49-3 and 49-4. As a result, lubricating oil can be appropriately supplied to the entire circumference of the

thrust bearing surfaces

13i and 13j, and wear of the

thrust bearing surfaces

13i and 13j can be prevented.

(First modification)
FIG. 6 is a diagram showing the cross-sectional shape of the thrust bearing surface 113i of the first modified example. Constituent elements that are substantially the same as those of the supercharger TC of the above-described embodiment are given the same reference numerals, and descriptions thereof are omitted. As shown in FIG. 6, the thrust bearing surface 113i of the first modified example includes oil drain grooves 145. As shown in FIG. A thrust bearing surface 113i of the first modified example differs from the thrust bearing surface 13i of the above embodiment only in the shape of the oil drain groove 145 .

The oil drain groove 145 includes an inclined portion 145a. The inclined portion 145a is formed on the side surface of the oil drain groove 145 on the forward side in the rotation direction RD. The inclined portion 145 a is formed between the groove bottom of the oil drain groove 145 and the tapered portion 41 . The axial height of the inclined portion 145 a gradually increases from the groove bottom of the oil drain groove 145 toward the tapered portion 41 . That is, the axial height of the inclined portion 145a gradually increases toward the front side in the rotational direction RD. The inclined portion 145a has a certain angle with respect to a plane orthogonal to the axial direction. The inclination angle of the inclined portion 145a is smaller than the inclination angle of the end portion of the oil drain groove 45 of the above-described embodiment on the front side in the rotational direction RD.

Thus, the thrust bearing surface 113i of the first modification includes the oil drain groove 145 having the inclined portion 145a. This makes it easier for the lubricating oil flowing through the oil drain groove 145 to flow toward the tapered portion 41 . As a result, more lubricating oil can be supplied to the tapered portion 41 than in the above embodiment.

(Second modification)
FIG. 7 is a front view of a thrust bearing surface 213i of a second modified example. Constituent elements that are substantially the same as those of the supercharger TC of the above-described embodiment are given the same reference numerals, and descriptions thereof are omitted. As shown in FIG. 7, the thrust bearing surface 213i of the second modification includes non-through grooves 220. As shown in FIG. The thrust bearing surface 213i of the second modification differs from the thrust bearing surface 13i of the above embodiment only in that non-through grooves 220 are provided.

The non-through groove 220 is formed in the tapered portion 41 . The non-through groove 220 is separated from the oil drain groove 45 forward in the rotational direction RD. However, the non-through groove 220 may be adjacent to the oil drain groove 45 in the circumferential direction and communicate with each other. The non-through groove 220 communicates with the chamfered portion 49 and extends in the radial direction. The inner diameter end of the non-through groove 220 opens to the chamfered portion 49, and the outer diameter end does not open to the outer peripheral edge of the thrust bearing surface 13i. The inner diameter end of the non-through groove 220 is connected to the chamfered portion 49 , and the outer diameter end of the non-through groove 220 is located within the tapered portion 41 . That is, the non-through groove 220 does not radially penetrate the thrust bearing surface 213i.

A portion of the lubricating oil that has flowed into the chamfered portion 49 from the oil supply groove 39 is introduced into the non-through groove 220 . The lubricating oil introduced into the non-through groove 220 is supplied from the non-through groove 220 to the tapered portion 41 . The non-through groove 220 is arranged on the rear side in the rotational direction RD with respect to the center of the tapered portion 41 in the circumferential direction. The lubricating oil flows in the rotation direction RD as the shaft 15 rotates. Therefore, by arranging the non-penetrating groove 220 on the rear side in the rotational direction RD with respect to the center in the circumferential direction of the tapered portion 41, more lubricating oil is supplied to the tapered portion 41 than in the case of arranging it on the front side in the rotational direction RD. can do. As a result, it is possible to easily maintain the necessary amount of oil and hydraulic pressure for the thrust bearing surface 13i.

Thus, the thrust bearing surface 213i of the second modified example has the non-through groove 220 in the tapered portion 41. As shown in FIG. As a result, more lubricating oil can be supplied to the taper portion 41 than in the above-described embodiment. As a result, lubricating oil can be appropriately supplied to the entire circumference of the thrust bearing surface 213i, and wear of the thrust bearing surface 213i can be prevented.

Although the embodiments of the present disclosure have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to such 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.

An example in which the bearing 13 is provided in the supercharger TC has been described above. However, the bearing 13 may be provided in a device other than the supercharger TC.

An example in which the bearing 13 is a semi-floating bearing has been described above. However, the bearing 13 may be a bearing other than the semi-floating bearing as long as it has a thrust bearing surface.

An example in which the non-penetrating groove 220 is located on the rear side in the rotational direction with respect to the center of the tapered portion 41 in the circumferential direction has been described above. However, without being limited to this, the non-penetrating groove 220 may be positioned forward in the rotational direction with respect to the center of the tapered portion 41 in the circumferential direction.

13 Bearing 13a Body 13i Thrust bearing surface 13j Thrust bearing surface 15 Shaft 39 Oil supply groove 41 Tapered portion 41-1 Tapered portion 41-2 Tapered portion 41-3 Tapered portion 41-4 Tapered portion 45 Drainage groove 47 Partition wall portion 49 Chamfered portion 49-1 Chamfered portion 49-2 Chamfered portion 49-3 Chamfered portion 49-4 Chamfered portion 145 Oil drainage groove 145a Inclined portion 220 Non-through groove TC Turbocharger

Claims

an annular body through which the shaft is inserted;
a radial bearing surface provided on the inner peripheral surface of the main body and radially facing the shaft;
a plurality of oil supply grooves provided in the radial bearing surface and extending in the axial direction of the main body;
a thrust bearing surface provided on the end surface of the main body;
a plurality of tapered portions provided on the thrust bearing surface at intervals in the circumferential direction of the main body and becoming shallower in the rotational direction of the shaft;
a partition wall provided on the thrust bearing surface and arranged between the plurality of tapered portions and an outer peripheral edge of the thrust bearing surface;
an oil drain groove provided in the thrust bearing surface and connecting the oil supply groove and the outer peripheral edge;
A plurality of chamfered portions provided between the radial bearing surface and the thrust bearing surface and partitioned from each other in the circumferential direction by the plurality of oil supply grooves, wherein when viewed from the axial direction, each chamfered portion a plurality of chamfers each having an area larger than half the area of the oil supply groove;
comprising a
bearing.
The oil drain groove has an inclined portion on the forward side in the rotational direction,
A bearing according to claim 1.
It further comprises a non-through groove provided in the tapered portion, wherein an inner diameter end of the non-through groove is connected to the chamfered portion, and an outer diameter end of the non-through groove is positioned within the tapered portion. ,
3. A bearing according to claim 1 or 2.
The non-through groove is located on the rear side in the rotational direction with respect to the center of the tapered portion in the circumferential direction,
4. A bearing according to claim 3.
A turbocharger comprising the bearing according to any one of claims 1 to 4.