Bearing structure and supercharger

Abstract

This bearing structure (S) is provided with: a shaft (15); a bearing (13a) that includes an inner ring (13a1), an outer ring (13a2), and rolling elements (13a3) provided between the inner ring (13a1) and the outer ring (13a2), and that supports the shaft (15); a bearing housing (3) that accommodates the bearing (13a); a side wall part (3j) which is provided in the bearing housing (3) and which faces the rolling body (13a3) in the axial direction of the shaft (15) across the entire region in the circumferential direction of the shaft (15); an annular groove (43) defined between the side wall portion (3j) and the bearing (13a) and extending in the circumferential direction; an oil discharge port provided in the bearing housing (3); and a communication path (45) that connects the annular groove (43) and the oil discharge port, and that penetrates the bearing housing (3) in a direction intersecting the axial direction.

Description

Technical Field

[0001] The present disclosure relates to a bearing structure and a supercharger. This application claims the benefit of priority based on Japanese Patent Application No. 2023-066482, filed on April 14, 2023, the contents of which are incorporated herein by reference. Background Art

[0002] Bearings that pivotally support a shaft are used in various devices. For example, Patent Document 1 discloses a supercharger equipped with a rolling bearing that pivotally supports a shaft.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6168739 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] Lubricating oil is supplied to rolling bearings used in superchargers and other applications. The lubricating oil supplied to the rolling bearings is discharged from the bearings and scattered around. Therefore, improving oil sealing is desirable to prevent the lubricating oil from leaking into components surrounding the rolling bearings.

[0008] An object of the present disclosure is to provide a bearing structure and a supercharger capable of improving oil sealing performance.

[0009] Solutions to Problems

[0010] In order to solve the above-mentioned problems, the bearing structure disclosed in the present invention includes: a shaft; a bearing, which includes an inner ring, an outer ring, and a rolling element arranged between the inner ring and the outer ring, and axially supports the shaft; a bearing housing, which accommodates the bearing; a side wall portion, which is arranged in the bearing housing and is opposite to the rolling element in the axial direction of the shaft over the entire circumferential area of ​​the shaft; an annular groove, which is divided between the side wall portion and the bearing and extends in the circumferential direction; an oil drain port, which is arranged in the bearing housing; and a connecting path, which connects the annular groove with the oil drain port and passes through the bearing housing in a direction intersecting with the axial direction.

[0011] It may also include: a bearing hole, which is arranged in the bearing housing; and a fitting component, which is provided integrally with or separately from the outer ring, and whose outer peripheral surface is fitted with the inner peripheral surface of the bearing hole, and the side wall portion is axially opposite to the outer peripheral edge of the side of the fitting component over the entire circumferential area.

[0012] The inner diameter of the annular groove may also be equivalent to the inner diameter of the outer ring.

[0013] A guide portion may be provided in the communication passage to guide the lubricating oil discharged through the communication passage toward the oil discharge port.

[0014] In order to solve the above-mentioned problems, the supercharger of the present disclosure includes the above-mentioned bearing structure.

[0015] The effects of the invention are as follows.

[0016] According to the present disclosure, oil sealing performance can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic cross-sectional view of a supercharger according to an embodiment of the present disclosure.

[0018] Figure 2 yes Figure 1 Extracted image of the dotted line part.

[0019] Figure 3 It shows Figure 2 Cross-sectional view of section AA.

[0020] Figure 4 This is a schematic cross-sectional view of a bearing structure according to a modified example. DETAILED DESCRIPTION

[0021] The following describes embodiments of the present disclosure with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values ​​shown in the embodiments are merely examples to facilitate understanding and, unless otherwise specified, do not limit the present disclosure. Furthermore, in this specification and the accompanying drawings, elements having substantially the same function or structure are denoted by the same reference numerals to avoid repeated descriptions, and illustrations of elements not directly related to the present disclosure are omitted.

[0022] Figure 1 This is a simplified cross-sectional view of the supercharger TC. Figure 1 The direction of arrow L shown is explained as the left side of the supercharger TC. Figure 1 The direction of arrow R shown is explained as the right side of the supercharger TC. Figure 1 As shown, the supercharger TC includes a supercharger body 1. The supercharger 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 a fastening bolt 11.

[0023] A protrusion 3a is provided on the outer circumferential surface of the bearing housing 3. The protrusion 3a is provided on the turbine housing 5 side. The protrusion 3a protrudes radially from the bearing housing 3. A protrusion 5a is provided on the outer circumferential surface of the turbine housing 5. The protrusion 5a is provided on the bearing housing 3 side. The protrusion 5a protrudes radially from the turbine housing 5. The bearing housing 3 and the turbine housing 5 are fastened together 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.

[0024] A bearing hole 3b is formed in the bearing housing 3. The bearing hole 3b extends through the bearing housing 3 in the left-right direction. A pair of bearings 13 are housed in the bearing holes 3b. The bearings 13 are rolling bearings. The bearings 13 rotatably support the shaft 15. A turbine impeller 17 is provided at the left end of the shaft 15. The turbine impeller 17 is rotatably housed in the turbine housing 5. A compressor impeller 19 is provided at the right end of the shaft 15. The compressor impeller 19 is rotatably housed in the compressor housing 7. An oil drain port 3c is formed at the bottom of the bearing housing 3 to drain lubricating oil scattered from the bearings 13.

[0025] An air intake port 21 is formed in the compressor housing 7. The air intake port 21 opens to the right side of the supercharger TC. The air intake port 21 is connected to an air filter (not shown). A diffuser flow path 23 is formed by the opposing surfaces of the bearing housing 3 and the compressor housing 7. The diffuser flow path 23 boosts the air pressure. The diffuser flow path 23 is annular in shape. The diffuser flow path 23 communicates with the air intake port 21 radially inwardly via the compressor impeller 19.

[0026] A compressor scroll flow path 25 is provided in the compressor housing 7. The compressor scroll flow path 25 is formed in an annular shape. The compressor scroll flow path 25 is located radially outside the shaft 15, for example, compared to the diffuser flow path 23. The compressor scroll flow path 25 is connected to the air intake of the engine (not shown) and the diffuser flow path 23. If the compressor impeller 19 rotates, air is sucked into the compressor housing 7 from the air intake 21. The sucked air is pressurized and accelerated in the process of flowing between the blades of the compressor impeller 19. The pressurized and accelerated air is pressurized in the diffuser flow path 23 and the compressor scroll flow path 25. The pressurized air is guided to the air intake of the engine.

[0027] The turbine housing 5 is formed with a discharge port 27. 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). The turbine housing 5 is formed with a communication passage 29 and a turbine vortex flow path 31. The turbine vortex flow path 31 is formed in an annular shape. The turbine vortex flow path 31 is located radially outward of the turbine impeller 17, for example, relative to the communication passage 29. The turbine vortex flow path 31 is connected to a gas inlet (not shown). Exhaust gas discharged from the exhaust manifold of the engine (not shown) is guided to the gas inlet. The communication passage 29 connects the turbine vortex flow path 31 with the discharge port 27 via the turbine impeller 17. The exhaust gas guided from the gas inlet to the turbine vortex flow path 31 is guided to the discharge port 27 via the communication passage 29 and the turbine impeller 17. The exhaust gas guided to the discharge port 27 rotates the turbine impeller 17 during its circulation.

[0028] The rotational force of the turbine impeller 17 is transmitted to the compressor impeller 19 via the shaft 15. When the compressor impeller 19 rotates, the air pressure is increased as described above. In this way, the air is guided to the air intake of the engine.

[0029] Figure 2 It is extracted Figure 1 The dotted line part of the diagram. Figure 2 As shown, a bearing structure S is provided inside the bearing housing 3. The bearing structure S includes the bearing housing 3, the bearing 13, and the shaft 15. Hereinafter, the axial direction, the circumferential direction, and the radial direction of the shaft 15 are also simply referred to as the axial direction, the circumferential direction, and the radial direction, respectively.

[0030] Two bearings 13, bearing 13a and bearing 13b, are installed in the bearing hole 3b of the bearing housing 3. Bearing 13a and bearing 13b are separated in the axial direction. Bearing 13a is located to the left of bearing 13b. Bearing 13a is the bearing 13 on the turbine impeller 17 side. Bearing 13b is the bearing 13 on the compressor impeller 19 side. As described below, lubricating oil is supplied to the bearings 13.

[0031] The bearing 13a includes an inner ring 13a1, an outer ring 13a2, rolling elements 13a3, and a retainer 13a4. The inner circumferential surface of the inner ring 13a1 fits into the outer circumferential surface of the shaft 15. The inner ring 13a1 rotates integrally with the shaft 15. The outer ring 13a2 is coaxial with the inner ring 13a1. The outer ring 13a2 is positioned radially outward relative to the inner ring 13a1. Multiple rolling elements 13a3 are positioned between the inner ring 13a1 and the outer ring 13a2. The retainer 13a4 retains the multiple rolling elements 13a3.

[0032] Bearing 13b includes an inner ring 13b1, an outer ring 13b2, rolling elements 13b3, and a retainer 13b4. The inner circumference of inner ring 13b1 fits into the outer circumference of shaft 15. Inner ring 13b1 rotates integrally with shaft 15. Outer ring 13b2 is coaxial with inner ring 13b1 and radially outward of inner ring 13b1. Multiple rolling elements 13b3 are positioned between inner ring 13b1 and outer ring 13b2. Retainer 13b4 retains these rolling elements 13b3.

[0033] Figure 2 , an example is shown in which the rolling elements 13a3 and 13b3 are spherical. However, the rolling elements 13a3 and 13b3 may be shaped other than spherical, such as cylindrical or truncated cone shapes.

[0034] The inner ring 13a1 is integrally formed with the spacer 33a. The spacer 33a has a cylindrical shape. The left end of the spacer 33a is connected to the right end of the inner ring 13a1. The shaft 15 is inserted through the spacer 33a. The inner ring 13a1 and the spacer 33a rotate integrally.

[0035] The inner ring 13b1 is integrally formed with the spacer 33b. The spacer 33b has a cylindrical shape. The right end of the spacer 33b is connected to the left end of the inner ring 13b1. The shaft 15 is inserted through the spacer 33b. The inner ring 13b1 and the spacer 33b rotate integrally. The left end of the spacer 33b abuts the right end of the spacer 33a.

[0036] The outer rings 13a2 and 13b2 are integrally formed with the fitting member 35. The fitting member 35 has a cylindrical shape. The outer ring 13a2 is connected to the left end of the inner circumference of the fitting member 35. The outer ring 13b2 is connected to the right end of the inner circumference of the fitting member 35. The outer circumferential surface of the fitting member 35 fits into the inner circumferential surface of the bearing hole 3b. The outer rings 13a2, 13b2, and fitting member 35 are held so as to prevent relative rotation with respect to the inner circumferential surface of the bearing hole 3b.

[0037] The bearing housing 3 is provided with a partition wall 3d. The partition wall 3d separates the interior space of the bearing housing 3 from the space within the turbine housing 5 that houses the turbine impeller 17. A through-hole 3d1 is provided in the partition wall 3d. The through-hole 3d1 extends horizontally through the partition wall 3d. A sealing ring 37 is mounted on the inner circumferential surface of the through-hole 3d1. The left end of the shaft 15 engages with the inner circumferential surface of the sealing ring 37. The turbine impeller 17, mounted on the left end of the shaft 15, is positioned to the left of the partition wall 3d.

[0038] As described below, lubricating oil is discharged from the bearing 13a toward the turbine impeller 17. The seal ring 37 suppresses leakage of the lubricating oil discharged from the bearing 13a toward the turbine impeller 17. However, using only the seal ring 37 may not adequately suppress leakage of lubricating oil from the bearing 13a toward the turbine impeller 17. As described below, the bearing structure S of this embodiment has been studied to effectively suppress such leakage of lubricating oil.

[0039] A branch oil passage 3e is formed in the bearing housing 3. The branch oil passage 3e extends in the axial direction of the shaft 15. The branch oil passage 3e extends substantially parallel to the bearing hole 3b. The branch oil passage 3e is located vertically above the bearing hole 3b.

[0040] The branch oil source passage 3e opens on the right side. A sealing plate 39 is attached to the opening of the branch oil source passage 3e. The sealing plate 39 is generally annular. It seals the opening of the branch oil source passage 3e. The inner diameter of the sealing plate 39 is smaller than that of the bearing hole 3b. A radially inner portion of the sealing plate 39 protrudes radially inward from the bearing hole 3b.

[0041] The through hole 3f opens into the branch source oil passage 3e. The through hole 3f is formed in the bearing housing 3. The through hole 3f extends from the outside of the bearing housing 3 to the branch source oil passage 3e. Oil delivered from an oil pump (not shown) is supplied to the branch source oil passage 3e through the through hole 3f.

[0042] The bearing housing 3 has a through-hole 3g and a through-hole 3h formed therein. Each of the through-holes 3g and 3h extends through the bearing housing 3, extending from the inner circumferential surface of the branch oil passage 3e to the inner circumferential surface of the bearing hole 3b. The through-holes 3g and 3h connect the branch oil passage 3e to the bearing hole 3b, respectively. The through-holes 3g and 3h are spaced apart in the axial direction.

[0043] The fitting member 35 has a through-hole 35a and a through-hole 35b. The through-hole 35a and the through-hole 35b extend through the fitting member 35 from the outer circumferential surface to the inner circumferential surface of the fitting member 35. The through-hole 35a and the through-hole 35b connect the outer circumferential surface of the fitting member 35 to the inner circumferential surface of the fitting member 35. The through-hole 35a and the through-hole 35b are separated in the axial direction.

[0044] The through-hole 3g of the bearing housing 3 communicates with the through-hole 35a of the fitting component 35. Therefore, lubricating oil is supplied from the branch source oil passage 3e through the through-hole 3g and the through-hole 35a to the interior of the fitting component 35. The through-hole 3h of the bearing housing 3 communicates with the through-hole 35b of the fitting component 35. Therefore, lubricating oil is supplied from the branch source oil passage 3e through the through-hole 3h and the through-hole 35b to the interior of the fitting component 35.

[0045] For example, Figure 2 In the figure, the solid arrows indicate the supply of lubricating oil from the branch source oil passage 3e through the through-hole 3g and the through-hole 35a to the interior of the fitting component 35. The lubricating oil supplied to the interior of the fitting component 35 passes between the inner race 13a1 and the outer race 13a2 of the bearing 13a and is discharged toward the turbine impeller 17. The lubricating oil supplied to the interior of the fitting component 35 passes between the inner race 13b1 and the outer race 13b2 of the bearing 13b and is also discharged toward the compressor impeller 19.

[0046] The lubricating oil supplied from the branch source oil passage 3e to the bearing hole 3b is also sent to the outer peripheral surface of the fitting component 35. For example, Figure 2 In FIG, the dotted arrows indicate that lubricating oil is supplied from the branch source oil passage 3e through the through-hole 3g to the outer peripheral surface of the fitting member 35. The lubricating oil supplied to the outer peripheral surface of the fitting member 35 is sent to the left side in the axial direction and discharged toward the turbine impeller 17. The lubricating oil supplied to the outer peripheral surface of the fitting member 35 is sent to the right side in the axial direction and also discharged toward the compressor impeller 19.

[0047] An oil baffle member 41 is provided radially inward of the sealing plate 39. The oil baffle member 41 is annular and fits into the outer circumferential surface of the shaft 15. The left end of the oil baffle member 41 abuts the right end of the inner race 13b1 of the bearing 13b. The oil baffle member 41 disperses the lubricating oil that has lubricated the bearing 13b on the compressor impeller 19 side radially outward. This prevents leakage of lubricating oil from the bearing 13b into the compressor impeller 19.

[0048] A through-hole 35c is formed in the lower portion of the fitting member 35. The through-hole 35c is axially positioned between the bearings 13a and 13b. The through-hole 35c extends through the fitting member 35 from its outer circumferential surface to its inner circumferential surface. The through-hole 35c connects the outer circumferential surface of the fitting member 35 with the inner circumferential surface of the fitting member 35.

[0049] A through hole 3i is formed in the bearing housing 3 at a position radially opposed to the through hole 35c of the fitting member 35. The through hole 3i penetrates the bearing housing 3 in the radial direction. The through hole 3i connects the bearing hole 3b with the oil drain port 3c (see Figure 1 ) connected.

[0050] The through-hole 35c of the fitting component 35 communicates with the through-hole 3i of the bearing housing 3. Therefore, a portion of the lubricating oil supplied from the branch source oil passage 3e to the interior of the fitting component 35 is discharged downward through the through-hole 35c and the through-hole 3i. A portion of the lubricating oil supplied from the branch source oil passage 3e to the outer peripheral surface of the fitting component 35 is discharged downward through the through-hole 3i.

[0051] Figure 3 It shows Figure 2 The sectional view of the AA section. Figure 2 and Figure 3 As shown, the bearing housing 3 is formed with a side wall portion 3j. The side wall portion 3j protrudes radially inward from the inner circumferential surface of the bearing hole 3b. The side wall portion 3j is provided to the left of the bearing 13a on the turbine impeller 17 side. The side wall portion 3j is axially opposed to the left side surface of the bearing 13a on the turbine impeller 17 side.

[0052] The side wall portion 3j is annular in shape. It covers the entire outer circumference of the shaft 15. An annular groove 43 is defined between the side wall portion 3j and the bearing 13a. The annular groove 43 is a space between the right side of the side wall portion 3j and the left side of the bearing 13a, with the width of the shaft 15 in the axial direction. The annular groove 43 extends circumferentially and is coaxial with the shaft 15.

[0053] An abutment surface 3j1 is provided on the right side of the side wall portion 3j, radially outward of the annular groove 43. This abutment surface 3j1 axially abuts the left side surface of the outer ring 13a2 of the bearing 13a and the left side surface 35d of the fitting component 35. The annular groove 43 is continuous with the inner circumference of the abutment surface 3j1. The annular groove 43 is defined between the right side surface of the side wall portion 3j, excluding the abutment surface 3j1, and the left side portion of the bearing 13a.

[0054] The inner diameter of the annular groove 43 corresponds to the inner diameter of the outer ring 13a2. This term "corresponding to the inner diameter of the outer ring 13a2" does not necessarily mean that the inner diameter is exactly the same as that of the outer ring 13a2. It also includes cases where the inner diameter deviates from the inner diameter of the outer ring 13a2 by a value within a predetermined range. However, the inner diameter of the annular groove 43 does not necessarily have to correspond to the inner diameter of the outer ring 13a2.

[0055] A communication passage 45 is formed in the bearing housing 3. The communication passage 45 is connected to the annular groove 43 and passes through the bearing housing 3 in a direction intersecting the axial direction of the shaft 15. Figure 2 and Figure 3 In the example shown in FIG. 1 , the communication passage 45 extends downward from the annular groove 43 and penetrates the bearing housing 3 in the radial direction of the shaft 15. The extending direction of the communication passage 45 may be inclined relative to the radial direction when viewed in a direction perpendicular to the axial direction, and may be inclined relative to the vertical direction when viewed in the axial direction. The communication passage 45 connects the annular groove 43 with the oil discharge port 3c (see FIG. 1 ). Figure 1 ) connected.

[0056] The side wall portion 3j is opposed to the rolling element 13a3 in the axial direction of the shaft 15 over the entire circumferential area of ​​the shaft 15. Figure 2 As indicated by the solid arrows, the lubricating oil that passes between the inner race 13a1 and outer race 13a2 of the bearing 13a on the turbine impeller 17 side and is discharged toward the turbine impeller 17 collides with the side wall portion 3j. This prevents the lubricating oil discharged from the bearing 13a toward the turbine impeller 17 from leaking to a position closer to the turbine impeller 17 than the side wall portion 3j. Furthermore, the lubricating oil discharged from the bearing 13a toward the turbine impeller 17 collides with the side wall portion 3j and then is discharged downward through the annular groove 43 and the communication passage 45.

[0057] The side wall portion 3j also faces the outer peripheral edge of the side surface 35d of the fitting component 35 in the axial direction of the shaft 15 over the entire circumferential region of the shaft 15. Figure 2As shown by the dashed arrows, the lubricating oil discharged toward the turbine impeller 17 from the outer peripheral surface of the fitting member 35 collides with the side wall portion 3j. This prevents the lubricating oil discharged from the outer peripheral surface of the fitting member 35 toward the turbine impeller 17 from leaking to a position closer to the turbine impeller 17 than the side wall portion 3j. Furthermore, the lubricating oil discharged from the outer peripheral surface of the fitting member 35 toward the turbine impeller 17 collides with the side wall portion 3j and is then discharged downward through the communication passage 45.

[0058] An expanded diameter portion 15a, whose outer diameter is larger than the surrounding area, is provided on the shaft 15 to the left of the bearing 13a on the turbine impeller 17 side. The right end of the expanded diameter portion 15a contacts the left end of the inner ring 13a1 of the bearing 13a. A portion of the inner circumferential surface of the side wall portion 3j radially opposes a portion of the outer circumferential surface of the expanded diameter portion 15a.

[0059] The side wall portion 3j and the expanded diameter portion 15a form a narrowed portion 47a. The narrowed portion 47a is where the gap between the inner circumferential surface of the bearing housing 3 and the outer circumferential surface of the shaft 15 becomes narrower relative to the surrounding area. Forming the narrowed portion 47a between the side wall portion 3j and the shaft 15 more effectively prevents lubricating oil discharged from the outer circumferential surface of the bearing 13a or the fitting component 35 toward the turbine impeller 17 from leaking to a position closer to the turbine impeller 17 than the side wall portion 3j.

[0060] An expanded diameter portion 15b, different from the expanded diameter portion 15a, is provided on the shaft 15 to the left of the expanded diameter portion 15a. Like the expanded diameter portion 15a, the expanded diameter portion 15b is a portion of the shaft 15 whose outer diameter is enlarged relative to the surrounding area. Furthermore, a narrow portion 47b, different from the narrow portion 47a, is formed by the inner circumferential surface of the bearing housing 3 and the expanded diameter portion 15b. As described above, in the bearing structure S, a plurality of narrow portions 47a and 47b are provided at intervals in the axial direction of the shaft 15 between the bearing 13a and the seal ring 37 on the turbine impeller 17 side. This further effectively prevents lubricating oil discharged from the outer circumferential surface of the bearing 13a or the mating component 35 toward the turbine impeller 17 from leaking to a position closer to the turbine impeller 17 than the side wall portion 3j.

[0061] As described above, the bearing structure S of this embodiment includes a side wall portion 3j that faces the rolling element 13a3 in the axial direction of the shaft 15, extending across the entire circumference of the shaft 15; an annular groove 43 extending circumferentially between the side wall portion 3j and the bearing 13a; and a communication passage 45 that connects the annular groove 43 with the oil discharge port 3c and extends through the bearing housing 3 in a direction intersecting the axial direction. This allows lubricating oil that passes between the inner ring 13a1 and the outer ring 13a2 of the bearing 13a and is discharged toward the turbine impeller 17 to collide with the side wall portion 3j, be discharged downward through the annular groove 43 and the communication passage 45, and be discharged to the outside through the oil discharge port 3c. Consequently, leakage of lubricating oil toward the turbine impeller 17 is suppressed. As described above, the bearing structure S of this embodiment can improve oil sealing performance. Furthermore, since lubricating oil can be prevented from accumulating around the bearing 13a, mechanical losses caused by this accumulation of lubricating oil can also be reduced.

[0062] exist Figure 2 and Figure 3 In the example of FIG, the side wall portion 3j is provided as a whole with the bearing housing 3. The side wall portion 3j may also be provided separately from the bearing housing 3 and mounted on the bearing housing 3.

[0063] In particular, the side wall portion 3j, extending across the entire circumference of the shaft 15, faces the outer peripheral edge of the side surface 35d of the fitting component 35 in the axial direction of the shaft 15. This allows lubricating oil that passes through the outer peripheral surface of the fitting component 35 and is discharged toward the turbine impeller 17 to collide with the side wall portion 3j, be discharged downward through the communication passage 45, and be discharged to the outside through the oil discharge port 3c. This effectively suppresses leakage of lubricating oil toward the turbine impeller 17, thereby further improving oil sealing performance.

[0064] However, the side wall portion 3 j may not face the outer peripheral edge of the side surface 35 d of the fitting member 35 in the axial direction of the shaft 15 in a portion of the circumference of the shaft 15 .

[0065] exist Figure 2 and Figure 3 In the example shown, the fitting component 35 is integral with the outer ring 13a2. However, the fitting component 35 may also be provided separately from the outer ring 13a2. In this case, for example, the fitting component 35 is also provided separately from the outer ring 13b2. Furthermore, the outer circumferential surface of the outer ring 13a2 and the outer circumferential surface of the outer ring 13b2 fit together with the inner circumferential surface of the fitting component 35.

[0066] exist Figure 2 and Figure 3 In the example of FIG, the inner ring 13a1 and the spacer member 33a are provided as a whole. However, the inner ring 13a1 and the spacer member 33a may also be provided separately. Figure 2 and Figure 3In the example of FIG, the inner ring 13b1 and the spacer member 33b are provided as a single body. However, the inner ring 13b1 may also be provided as a separate body from the spacer member 33b.

[0067] In particular, the inner diameter of the annular groove 43 is comparable to that of the outer ring 13a2. This prevents the lubricating oil that passes between the inner ring 13a1 and the outer ring 13a2 of the bearing 13a and is discharged toward the turbine impeller 17 from colliding with the abutment surface 3j1. Consequently, the lubricating oil discharged from the bearing 13a toward the turbine impeller 17 can be smoothly guided to the annular groove 43. Furthermore, compared to a case where the inner diameter of the annular groove 43 is larger than that of the outer ring 13a2, the area of ​​the abutment surface 3j1 is increased, enabling the outer ring 13a2 to be stably positioned by the abutment surface 3j1.

[0068] Figure 4 1 is a schematic cross-sectional view of a bearing structure SA according to a modified example. The bearing structure SA according to the modified example differs from the bearing structure S according to the present embodiment in that a guide portion 49 is provided in the communication passage 45 .

[0069] like Figure 4 As shown in FIG. 4 , the bearing structure SA includes a guide portion 49. The guide portion 49 is provided in the communication passage 45. The guide portion 49 guides the lubricating oil discharged through the communication passage 45 toward the oil discharge port 3 c. Figure 4 In the example of FIG, the guide portion 49 is provided in a portion of the side wall portion 3j facing the communication path 45. The guide portion 49 protrudes from the lower end portion of the side wall portion 3j toward the oil discharge port 3c. Figure 4 In the example shown in FIG. 4 , the protruding direction of the guide portion 49 is the lower right direction.

[0070] The guide portion 49 includes a guide surface 49a facing the communication passage 45. The guide surface 49a extends in a direction perpendicular to the horizontal and vertical directions and extends in a direction toward the oil discharge port 3c, that is, in a lower right direction. Lubricating oil discharged from the outer peripheral surface of the bearing 13a or the fitting component 35 toward the turbine impeller 17 collides with the sidewall portion 3j, is then transported to the communication passage 45, and is guided toward the oil discharge port 3c by the guide surface 49a of the guide portion 49. This allows the lubricating oil discharged through the communication passage 45 to be dispersed toward the oil discharge port 3c, thereby more effectively preventing the lubricating oil from leaking toward the turbine impeller 17.

[0071] While the embodiments of the present disclosure have been described above with reference to the accompanying drawings, it is self-evident that the present disclosure is not limited to the embodiments. It is clear to those skilled in the art that various variations or modifications can be envisioned within the scope of the claims, and such variations or modifications naturally fall within the technical scope of the present disclosure.

[0072] For example, in the above example, the side wall portion 3j, the annular groove 43, and the communication passage 45 are provided on the bearing 13a on the turbine impeller 17 side of the supercharger TC. However, the side wall portion 3j, the annular groove 43, and the communication passage 45 may also be provided on other bearings 13 in the supercharger TC other than the bearing 13a. This can prevent the lubricating oil from leaking into components other than the turbine impeller 17 disposed around the bearing 13.

[0073] For example, in the above-mentioned example, the supercharger TC is provided with the bearing structures S and SA. However, the bearing structures S and SA can also be applied to devices other than the supercharger TC that have rolling bearings.

[0074] Explanation of symbols

[0075] 3—bearing housing, 3b—bearing hole, 3c—oil drain port, 3j—side wall portion, 13a—bearing, 13a1—inner ring, 13a2—outer ring, 13a3—rolling element, 15—shaft, 35—fitting component, 35d—side surface, 43—annular groove, 45—connecting passage, 49—guide portion, S—bearing structure, SA—bearing structure, TC—supercharger.

Claims

1. A bearing structure, characterized in that: have: axis; a bearing comprising an inner ring, an outer ring, and rolling elements disposed between the inner ring and the outer ring, and axially supporting the shaft; a bearing housing for housing the bearing; a side wall portion provided in the bearing housing and facing the rolling element in the axial direction of the shaft over the entire circumference of the shaft; an annular groove defined between the side wall portion and the bearing and extending in the circumferential direction; an oil drain port, which is provided on the bearing housing; and A communication passage connects the annular groove with the oil discharge port and penetrates the bearing housing in a direction intersecting the axial direction.

2. The bearing structure according to claim 1, characterized in that: The invention comprises: a bearing hole provided in the bearing housing; and a fitting member provided integrally with or separately from the outer ring, the outer peripheral surface of the fitting member being fitted with the inner peripheral surface of the bearing hole. The side wall portion faces the outer peripheral edge of the side surface of the fitting member in the axial direction over the entire region in the circumferential direction.

3. The bearing structure according to claim 1, characterized in that: The inner diameter of the annular groove corresponds to the inner diameter of the outer ring.

4. The bearing structure according to claim 1, characterized in that: A guide portion is provided in the communication passage and guides the lubricating oil discharged through the communication passage toward the oil discharge port.

5. A supercharger, characterized in that: A bearing structure according to any one of claims 1 to 4 is provided.

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