Bearing structure and turbocharger

Abstract

A bearing structure (S) has: a shaft (15); a bearing (13a) having an inner ring (13a1), an outer ring (13a2), and rolling elements (13a3) provided between the inner ring (13a1) and the outer ring (13a2), and axially supporting the shaft (15); a bearing housing (3) accommodating the bearing (13a); a side wall section (3j) formed in the bearing housing (3) and facing the rolling elements (13a3) in an axial direction of the shaft over an entire area in a circumferential direction of the shaft (15); an annular groove (43) defined between the side wall section (3j) and the bearing (13a) and extending in the circumferential direction; an oil discharge port formed in the bearing housing (3); and a connecting passage (45) which allows the annular groove (43) and the oil discharge port to be connected to each other, and which passes through the bearing housing (3) in a direction that intersects the axial direction.

Description

Technical field

[0001] The present disclosure relates to a bearing structure and a turbocharger. This application claims the priority effect of Japanese patent application No. 2023-066482, which was filed on April 14, 2023, and whose contents are incorporated herein. Technical background

[0002] Various devices have used a bearing that axially supports a shaft. For example, patent literature 1 discloses a turbocharger that has rolling bearings which axially support a shaft. Citation list of patent literature

[0003] Patent literature 1: JP 6168739 B2 Summary Technical Problem

[0004] Lubricating oil is supplied to a rolling bearing used in a turbocharger or similar device. The lubricating oil supplied to the rolling bearing is released by the bearing and distributed around its circumference. Therefore, to prevent the lubricating oil from escaping to components surrounding the rolling bearing, an improvement in the oil seal's performance is desirable.

[0005] The purpose of the present disclosure is to provide a bearing structure and a turbocharger that can enable an improvement in oil sealing performance. Solution to the problem

[0006] To solve the aforementioned problem, a bearing structure is provided according to the present disclosure, comprising: a shaft; a bearing having an inner ring, an outer ring, and rolling elements provided between the inner ring and the outer ring, and axially supporting the shaft; a bearing housing accommodating the bearing; a side wall section formed in the bearing housing, which faces the rolling elements in an axial direction of the shaft over an entire area in a circumferential direction of the shaft; an annular groove defined between the side wall section and the bearing, extending in the circumferential direction; an oil discharge port formed in the bearing housing; and a connecting passage allowing the annular groove and the oil discharge port to be connected to each other, and which passes through the bearing housing in a direction intersecting the axial direction.

[0007] The bearing structure may further comprise: a bearing bore formed in the bearing housing; and a mating component, provided integrally with or separately from the outer ring, having an outer circumferential surface that is permitted to be fitted to an inner circumferential surface of the bearing bore. The side wall section may be axially adjacent to an outer circumferential edge of a side surface of the mating component over its entire circumferential area.

[0008] The ring-shaped groove can have an inner diameter that corresponds to the inner diameter of the outer ring.

[0009] The bearing structure may also have a guide section provided in the connecting passage, which guides lubricating oil discharged through the connecting passage in one direction towards the oil discharge port.

[0010] To solve the aforementioned problem, a turbocharger with the aforementioned bearing structure is provided according to the present disclosure. Advantageous effects of the invention

[0011] According to the present disclosure, the oil sealing performance can be improved. Brief description of the drawings Fig. Figure 1 is a schematic sectional view of a turbocharger according to an embodiment of the present disclosure. Fig. 2 is an extract view to show a section of Fig. 1, which is marked with single-dot dashed lines. Fig. Figure 3 is a sectional view showing a cross-section along line AA of Fig. 2. Fig. Figure 4 is a schematic sectional view of a storage structure according to a modification example. Description of exemplary implementations

[0012] An embodiment of the present disclosure will now be described with reference to the attached drawings. The dimensions, materials, and other specific numerical values ​​represented in the embodiment are merely examples used to facilitate understanding of the disclosure and do not limit the present disclosure unless specifically noted otherwise. Elements having essentially the same functions and configurations herein and in the drawings are designated with the same reference numerals to avoid redundant descriptions. Furthermore, representations of elements with no direct relation to the present disclosure have been omitted.

[0013] Fig. Figure 1 is a schematic sectional view illustrating a turbocharger TC. The following is a description assuming a direction indicated by the arrow L, which points in Fig. Figure 1 is shown as the left side of the turbocharger TC. A description is given assuming a direction indicated by the arrow R, which points in Fig. Figure 1 shows the right side of the turbocharger TC. As shown in Fig. As shown in Figure 1, the turbocharger TC has a turbocharger main body 1. The turbocharger main body 1 has a bearing housing 3, a turbine housing 5, and a compressor housing 7. The turbine housing 5 is coupled to a left side of the bearing housing 3 by a fastening mechanism 9. The compressor housing 7 is coupled to a right side of the bearing housing 3 by fastening bolts 11.

[0014] A projection 3a is formed on an outer circumferential surface of the bearing housing 3. The projection 3a is formed on the side of the turbine housing 5. The projection 3a extends radially forward of the bearing housing 3. A projection 5a is formed on an outer circumferential surface of the turbine housing 5. The projection 5a is formed on the side of the bearing housing 3. The projection 5a extends radially forward of the turbine housing 5. The bearing housing 3 and the turbine housing 5 are strap-mounted by the fastening mechanism 9. The fastening mechanism 9 is, for example, a G-coupling. The fastening mechanism 9 clamps the projection 3a and the projection 5a.

[0015] The bearing housing 3 has a bearing bore 3b formed within it. The bearing bore 3b passes through the bearing housing 3 in a clockwise and counterclockwise direction. A pair of bearings 13 are housed in the bearing bore 3b. The bearing 13 is a rolling bearing. The bearing 13 axially supports a shaft 15 to allow it to rotate.

[0016] A turbine impeller 17 is provided at a left end section of the shaft 15. The turbine impeller 17 is housed in the turbine casing 5 to allow rotation. A compressor impeller 19 is provided at a right end section of the shaft 15. The compressor impeller 19 is housed in the compressor casing 7 to allow rotation. An oil discharge port 3c is provided at the bottom of the bearing housing 3 to discharge lubricating oil that has spread from the bearing 13.

[0017] An intake port 21 is formed in the compressor housing 7. The intake port 21 opens on the right side of the turbocharger TC. The intake port 21 is connected to an air filter (not shown). A diffuser flow passage 23 is defined by the opposing surfaces of the bearing housing 3 and the compressor housing 7. The diffuser flow passage 23 increases the air pressure. The diffuser flow passage 23 has an annular shape. The diffuser flow passage 23 is connected to the intake port 21 on a radially inner side via the compressor impeller 19.

[0018] A compressor screw flow passage 25 is provided in the compressor housing 7. The compressor screw flow passage 25 has an annular shape. The compressor screw flow passage 25 is located, for example, on an outer side with respect to the diffuser flow passage 23 in a radial direction of the shaft 15. The compressor screw flow passage 25 is connected to an intake port of a machine (not shown) and the diffuser flow passage 23. When the compressor impeller 19 rotates, air is drawn from the intake port 21 into the compressor housing 7. The intake air is pressurized and accelerated as it flows through the blades of the compressor impeller 19. The pressure of the pressurized and accelerated air is increased in the diffuser flow passage 23 and the compressor screw flow passage 25.The air, whose pressure has been increased, is directed to the machine's intake port.

[0019] A discharge port 27 is formed in the turbine housing 5. The discharge port 27 opens on the left side of the turbocharger TC. The discharge port 27 is connected to an exhaust gas cleaning device (not shown). A connecting passage 29 and a turbine screw flow passage 31 are formed in the turbine housing 5. The turbine screw flow passage 31 has an annular shape. The turbine screw flow passage 31 is located, for example, on an outer side with respect to the connecting passage 29 in a radial direction of the turbine impeller 17. The turbine screw flow passage 31 is connected to a gas inlet port (not shown). Exhaust gas discharged from an exhaust manifold of the machine (not shown) is directed to the gas inlet port. The connecting passage 29 allows a connection between the turbine screw flow passage 31 and the discharge port 27 via the turbine impeller 17.The exhaust gas, which has been routed from the gas inlet port to the turbine screw flow passage 31, is guided to the discharge port 27 via the connecting passage 29 and the turbine runner 17. The exhaust gas, which is routed to the discharge port 27, rotates the turbine runner 17 in the course of the flow.

[0020] A rotational force from 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 directed to the machine's intake port.

[0021] Fig. 2 is an extract view, to show a section of Fig. 1, which is marked with single-dot dashed lines. As in Fig. As shown in Figure 2, the bearing housing 3 contains a bearing structure S. The bearing structure S comprises the bearing housing 3, the bearings 13, and the shaft 15. The axial direction, the circumferential direction, and the radial direction of the shaft 15 are hereinafter also referred to simply as "axial direction," "circumferential direction," and "radial direction," respectively.

[0022] Two bearings 13, i.e., bearing 13a and bearing 13b, are provided in the bearing bore 3b of the bearing housing 3. Bearing 13a and bearing 13b are spaced apart axially. Bearing 13a is located on the left side of bearing 13b. Bearing 13a is the bearing 13 on the side of the turbine impeller 17. Bearing 13b is the bearing 13 on the side of the compressor impeller 19. As will be described later, lubricating oil is supplied to the bearings 13.

[0023] The bearing 13a has an inner ring 13a1, an outer ring 13a2, rolling elements 13a3, and a cage 13a4. An inner circumferential surface of the inner ring 13a1 is fitted to an outer circumferential surface of the shaft 15. The inner ring 13a1 rotates integrally with the shaft 15. The outer ring 13a2 is positioned coaxially with the inner ring 13a1. The outer ring 13a2 is provided on a radially outer side with respect to the inner ring 13a1. A plurality of rolling elements 13a3 are provided between the inner ring 13a1 and the outer ring 13a2. The cage 13a4 holds the plurality of rolling elements 13a3.

[0024] The bearing 13b has an inner ring 13b1, an outer ring 13b2, rolling elements 13b3, and a cage 13b4. An inner circumferential surface of the inner ring 13b1 is fitted to the outer circumferential surface of the shaft 15. The inner ring 13b1 rotates integrally with the shaft 15. The outer ring 13b2 is positioned coaxially with the inner ring 13b1. The outer ring 13b2 is provided on a radially outer side with respect to the inner ring 13b1. A plurality of rolling elements 13b3 are provided between the inner ring 13b1 and the outer ring 13b2. The cage 13b4 holds the plurality of rolling elements 13b3.

[0025] Fig. Figure 2 shows an example of the rolling elements 13a3 and 13b3, each of which has a spherical shape. However, the rolling elements 13a3 and 13b3 can each have a shape other than spherical, such as a columnar shape and a truncated cone shape.

[0026] The inner ring 13a1 is integrally fitted with a spacer component 33a. The spacer component 33a has a cylindrical shape. A left end portion of the spacer component 33a is connected to a right end portion of the inner ring 13a1. The shaft 15 is inserted through the spacer component 33a. The inner ring 13a1 rotates integrally with the spacer component 33a.

[0027] The inner ring 13b1 is integrally fitted with a spacer component 33b. The spacer component 33b has a cylindrical shape. A right end portion of the spacer component 33b is connected to a left end portion of the inner ring 13b1. The shaft 15 is inserted through the spacer component 33b. The inner ring 13b1 rotates integrally with the spacer component 33b. A left end portion of the spacer component 33b rests against a right end portion of the spacer component 33a.

[0028] The outer ring 13a2 and the outer ring 13b2 are integrally formed with a fitting component 35. The fitting component 35 has a cylindrical shape. The outer ring 13a2 is connected to a left end portion of an inner circumferential section of the fitting component 35. The outer ring 13b2 is connected to a right end portion of the inner circumferential section of the fitting component 35. An outer circumferential surface of the fitting component 35 is fitted to an inner circumferential surface of the bearing bore 3b. The outer ring 13a2, the outer ring 13b2, and the fitting component 35 are held in place to prevent rotation relative to the inner circumferential surface of the bearing bore 3b.

[0029] The bearing housing 3 has a partition 3d. The partition 3d separates an interior space of the bearing housing 3 from a space in the turbine housing 5, which accommodates the turbine impeller 17. A through-hole 3d1 is formed in the partition 3d. The through-hole 3d1 extends through the partition 3d in both clockwise and counterclockwise directions. A sealing ring 37 is attached to an inner circumferential surface of the through-hole 3d1. The left end section of the shaft 15 is fitted to an inner circumferential surface of the sealing ring 37. The turbine impeller 17, which is attached to the left end section of the shaft 15, is positioned on the left side of the partition 3d.

[0030] As will be described later, lubricating oil is released from the bearing 13a to the side of the turbine impeller 17. The sealing ring 37 prevents the lubricating oil from being released from the bearing 13a without escaping to the turbine impeller 17. However, it can be difficult to adequately prevent the lubricating oil from escaping from the bearing 13a to the turbine impeller 17 solely by means of the sealing ring 37. The bearing structure S according to this embodiment has been designed to effectively prevent such escape of the lubricating oil, as will be described later.

[0031] A branch oil origin passage 3e is formed in the bearing housing 3. The branch oil origin passage 3e extends in the axial direction of the shaft 15. The branch oil origin passage 3e extends substantially parallel to the bearing bore 3b. The branch oil origin passage 3e is located vertically above the bearing bore 3b.

[0032] The branch oil passage 3e opens to the right. A sealing plate 39 is attached to the opening of the branch oil passage 3e. The sealing plate 39 has a substantially ring-shaped form. The sealing plate 39 closes the opening of the branch oil passage 3e. The sealing plate 39 has an inner diameter that is smaller than the inner diameter of the bearing hole 3b. A portion of the sealing plate 39 on a radially inner side projects towards a radially inner side of the bearing hole 3b.

[0033] A through-hole 3f opens to the branch oil outlet 3e. The through-hole 3f is formed in the bearing housing 3. The through-hole 3f extends from an outer surface of the bearing housing 3 to the branch oil outlet 3e. Oil pumped out by an oil pump (not shown) is supplied through the through-hole 3f to the branch oil outlet 3e.

[0034] A through-hole 3g and a through-hole 3h are formed in the bearing housing 3. Each through-hole 3g and through-hole 3h extends through the bearing housing 3 from an inner circumferential surface of the branch oil passage 3e to the inner circumferential surface of the bearing hole 3b. Each through-hole 3g and through-hole 3h allows the branch oil passage 3e and the bearing hole 3b to communicate with each other. The through-hole 3g and the through-hole 3h are spaced apart axially.

[0035] A through-hole 35a and a through-hole 35b are formed in the fitting component 35. Each through-hole 35a and through-hole 35b extends through the fitting component 35 from the outer circumferential surface of the fitting component 35 to an inner circumferential surface of the fitting component 35. Each through-hole 35a and through-hole 35b allows the outer circumferential surface and the inner circumferential surface of the fitting component 35 to be in contact with each other. The through-hole 35a and the through-hole 35b are spaced apart from each other in the axial direction.

[0036] The through-hole 3g of the bearing housing 3 and the through-hole 35a of the mating component 35 are connected. Thus, lubricating oil is supplied from the branch oil source passage 3e to an inner side of the mating component 35 through through-hole 3g and through-hole 35a. The through-hole 3h of the bearing housing 3 and the through-hole 35b of the mating component 35 are connected. Thus, lubricating oil is supplied from the branch oil source passage 3e to the inner side of the mating component 35 through through-hole 3h and through-hole 35b.

[0037] For example, in Fig. 2 A state in which lubricating oil is supplied from the branch origin oil passage 3e to the inner side of the fitting component 35 through the through-hole 3g and the through-hole 35a, indicated by the through arrows. The lubricating oil supplied to the inner side of the fitting component 35 passes between the inner ring 13a1 and the outer ring 13a2 of the bearing 13a to be discharged to the side of the turbine impeller 17. The lubricating oil supplied to the inner side of the fitting component 35 passes between the inner ring 13b1 and the outer ring 13b2 of the bearing 13b to also be discharged to the side of the compressor impeller 19.

[0038] The lubricating oil supplied from the branch origin oil passage 3e to the bearing hole 3b is also supplied to the outer circumferential surface of the fitting component 35. For example, in Fig. 2 A state in which the lubricating oil is supplied from the branch origin oil passage 3e to the outer circumferential surface of the fitting component 35 through the through-hole 3g, indicated by the dashed arrows. The lubricating oil supplied to the outer circumferential surface of the fitting component 35 is delivered to the left along the axial direction to be discharged towards the side of the turbine impeller 17. The lubricating oil supplied to the outer circumferential surface of the fitting component 35 is delivered to the right along the axial direction to also be discharged towards the side of the compressor impeller 19.

[0039] An oil slinger component 41 is provided on a radially inner side with respect to the sealing plate 39. The oil slinger component 41 has an annular shape. The oil slinger component 41 is fitted to the outer circumferential surface of the shaft 15. A left end portion of the oil slinger component 41 rests against a right end portion of the inner ring 13b1 of the bearing 13b. The oil slinger component 41 distributes the lubricating oil, which has lubricated the bearing 13b on the side of the compressor impeller 19, to a radially outer side. As a result, the escape of lubricating oil from the bearing 13b to the compressor impeller 19 is prevented.

[0040] A through-hole 35c is formed in a lower part of the fitting component 35. The through-hole 35c is located axially between the bearing 13a and the bearing 13b. The through-hole 35c extends through the fitting component 35 from the outer circumferential surface of the fitting component 35 to the inner circumferential surface of the fitting component 35. The through-hole 35c allows the outer circumferential surface and the inner circumferential surface of the fitting component 35 to be in contact with each other.

[0041] A through-hole 3i is formed in the bearing housing 3 at a position that faces the through-hole 35c of the fitting component 35 in the radial direction. The through-hole 3i extends through the bearing housing 3 in the radial direction. The through-hole 3i allows the bearing hole 3b and the oil discharge port 3c (see Fig. 1) are connected to each other.

[0042] The through-hole 35c of the fitting component 35 and the through-hole 3i of the bearing housing 3 are connected. Thus, some of the lubricating oil supplied from the branch oil source passage 3e to the inner side of the fitting component 35 is discharged downwards through the through-hole 35c and the through-hole 3i. Some of the lubricating oil supplied from the branch oil source passage 3e to the outer circumferential surface of the fitting component 35 is discharged downwards through the through-hole 3i.

[0043] Fig. Figure 3 is a sectional view showing a cross-section along line AA of Fig. 2. As in Fig. 2 and Fig. As shown in Figure 3, a side wall section 3j is formed in the bearing housing 3. The side wall section 3j projects from the inner circumferential surface of the bearing bore 3b to a radially inner side. The side wall section 3j is located on the left side of the bearing 13a on the side of the turbine impeller 17. The side wall section 3j is axially opposite a left side surface of the bearing 13a on the side of the turbine impeller 17.

[0044] The side wall section 3j has an annular shape. The side wall section 3j covers the outer circumferential surface of the shaft 15 over its entire circumference. An annular groove 43 is defined between the side wall section 3j and the bearing 13a. The annular groove 43 is a space that has a width in the axial direction of the shaft 15 between a right-hand face of the side wall section 3j and a left-hand side of the bearing 13a. The annular groove 43 extends in the circumferential direction. The annular groove 43 is coaxial with the shaft 15.

[0045] A contact surface 3j1 is provided on a section of the right surface of the side wall section 3j on the radially outer side of the annular groove 43. The contact surface 3j1 rests axially against a left side surface of the outer ring 13a2 of the bearing 13a and a left side surface 35d of the fitting component 35. The annular groove 43 is continuous with an inner circumferential edge of the contact surface 3j1. The annular groove 43 is defined between a section, excluding the contact surface 3j1, of the right surface of the side wall section 3j and the left side of the bearing 13a.

[0046] The annular groove 43 has an inner diameter that corresponds to the inner diameter of the outer ring 13a2. This inner diameter can be not only an exact match, but also a diameter that deviates from it by a value within a predetermined range. However, it is not always necessary for the inner diameter of the annular groove 43 to match the inner diameter of the outer ring 13a2.

[0047] A connecting passage 45 is formed in the bearing housing 3. The connecting passage 45 is connected to the annular groove 43 and extends through the bearing housing 3 in a direction that intersects the axial direction of the shaft 15. In the example of Fig. 2 and Fig. 3 The connecting passage 45 extends downwards from the annular groove 43 to pass through the bearing housing 3 in the radial direction of the shaft 15. However, the direction of extension of the connecting passage 45 can be inclined with respect to the radial direction, viewed in a direction perpendicular to the axial direction, or it can be inclined with respect to a vertical direction, viewed in the axial direction. The connecting passage 45 allows the annular groove 43 and the oil discharge port 3c (see Fig. 1) are connected to each other.

[0048] The side wall section 3j lies opposite the rolling elements 13a3 in the axial direction of the shaft 15 over an entire area in the circumferential direction of the shaft 15. Therefore, as indicated by the continuous arrows in Fig. As indicated in Figure 2, the lubricating oil that has passed between the inner ring 13a1 and the outer ring 13a2 of the bearing 13a on the side of the turbine impeller 17, in order to be discharged to that side of the turbine impeller 17, is directed onto the side wall section 3j. This prevents the lubricating oil discharged from the bearing 13a to the side of the turbine impeller 17 from escaping to the side of the side wall section 3j located at the turbine impeller 17. Then, after striking the side wall section 3j, the lubricating oil discharged from the bearing 13a to the side of the turbine impeller 17 passes through the annular groove 43 and the connecting passage 45 in the aforementioned sequence to be discharged downwards.

[0049] The side wall section 3j also lies opposite an outer circumferential edge of the side surface 35d of the fitting component 35 in the axial direction of the shaft 15 over the entire area in the circumferential direction of the shaft 15. Consequently, as indicated by the dashed arrows in Fig. As indicated in section 2, the lubricating oil that has passed through the outer circumferential surface of the fitting component 35 to be discharged towards the side of the turbine impeller 17 is directed onto the side wall section 3j. This prevents the lubricating oil, which is discharged from the outer circumferential surface of the fitting component 35 to the side of the turbine impeller 17, from escaping to the side of the side wall section 3j located at the turbine impeller 17. Then, after impacting the side wall section 3j, the lubricating oil that has been discharged from the outer circumferential surface of the fitting component 35 to the side of the turbine impeller 17 passes through the connecting passage 45 to be discharged downwards.

[0050] A radially flared section 15a is formed on the left side of the bearing 13a on the side of the turbine impeller 17 in the shaft 15. The radially flared section 15a has an outer diameter that is flared relative to its circumference. A left end portion of the inner ring 13a1 of the bearing 13a abuts a right end portion of the radially flared section 15a. A portion of an inner circumferential surface of the side wall section 3j and a portion of an outer circumferential surface of the radially flared section 15a are opposite each other in the radial direction.

[0051] A narrowed section 47a is defined by the side wall section 3j and the radially widened section 15a. The narrowed section 47a is a section in which a gap between an inner circumferential surface of the bearing housing 3 and the outer circumferential surface of the shaft 15 is narrowed with respect to the circumference of the section. Since the narrowed section 47a is defined between the side wall section 3j and the shaft 15, the lubricating oil supplied from the bearing 13a or the outer circumferential surface of the mating component 35 to the side of the turbine impeller 17 is more effectively prevented from escaping to the side of the side wall section 3j located at the turbine impeller 17.

[0052] A radially expanded section 15b, distinct from the radially expanded section 15a, is formed on the left side of the radially expanded section 15a in the shaft 15. The radially expanded section 15b is a section of the shaft 15 whose outer diameter is expanded relative to the circumference of the section in the same manner as the radially expanded section 15a. Furthermore, a narrowed section 47b, distinct from the narrowed section 47a, is defined by the inner circumferential surface of the bearing housing 3 and the radially expanded section 15b. As described above, a plurality of narrowed sections, i.e., the narrowed sections 47a and 47b, are defined in the bearing structure S, spaced apart from one another in the axial direction of the shaft 15 between the bearing 13a on the side of the turbine impeller 17 and the sealing ring 37.This design more effectively prevents the lubricating oil, which is supplied from the bearing 13a or the outer circumferential surface of the fitting component 35 to the side of the turbine impeller 17, from escaping to the side of the turbine impeller 17 of the side wall section 3j.

[0053] As described above, the bearing structure S according to this embodiment has the following: the side wall section 3j, which is opposite the rolling elements 13a3 in the axial direction of the shaft 15 over the entire area in the circumferential direction of the shaft 15; the annular groove 43, which is defined between the side wall section 3j and the bearing 13a and extends in the circumferential direction; and the connecting passage 45, which allows a connection between the annular groove 43 and the oil discharge port 3c and passes through the bearing housing 3 in the direction that intersects the axial direction.With this design, the lubricating oil that has passed between the inner ring 13a1 and the outer ring 13a2 of the bearing 13a, intending to be discharged towards the side of the turbine impeller 17, is instead directed onto the side wall section 3j. From there, it is discharged downwards through the annular groove 43 and the connecting passage 45, and can then be discharged to an external surface through the oil discharge port 3c. This prevents the lubricating oil from escaping towards the side of the turbine impeller 17. As described above, the bearing structure S according to this embodiment improves oil sealing performance. Furthermore, it prevents the lubricating oil from stagnating around the bearing 13a. This also prevents mechanical losses caused by lubricating oil stagnation.

[0054] In the example of Fig. 2 and Fig. 3. The side wall section 3j is provided as a single piece with the bearing housing 3. However, the side wall section 3j can be provided separately from the bearing housing 3 and can be attached to the bearing housing 3.

[0055] Specifically, the side wall section 3j lies opposite the outer circumferential edge of the side surface 35d of the fitting component 35 in the axial direction of the shaft 15 over its entire circumference. This design causes the lubricating oil, which has passed through the outer circumferential surface of the fitting component 35 to be delivered to the turbine impeller 17, to strike the side wall section 3j and be discharged downwards through the connecting passage 45, and can then be discharged to the outside through the oil discharge port 3c. This more effectively prevents the lubricating oil from escaping towards the side of the turbine impeller 17. Consequently, the oil sealing performance can be significantly improved.

[0056] However, it is not always required that a part of the side wall section 3j in the circumferential direction of the shaft 15 is opposite the outer circumferential edge of the side surface 35d of the fitting component 35 in the axial direction of the shaft 15.

[0057] In the example of Fig. 2 and Fig. In section 3, the fitting component 35 is integrally formed with the outer ring 13a2. However, the fitting component 35 can 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. Then, an outer circumferential surface of the outer ring 13a2 and an outer circumferential surface of the outer ring 13b2 are fitted to the inner circumferential surface of the fitting component 35.

[0058] In the example of Fig. 2 and Fig. In section 3, the inner ring 13a1 is provided as a single piece with the spacer component 33a. However, the inner ring 13a1 can be provided separately from the spacer component 33a. In the example of Fig. 2 and Fig. In section 3, the inner ring 13b1 is provided as a single piece with the spacer component 33b. However, the inner ring 13b1 can be provided separately from the spacer component 33b.

[0059] Specifically, the inner diameter of the annular groove 43 corresponds to the inner diameter of the outer ring 13a2. This design prevents the lubricating oil, which has passed between the inner ring 13a1 and the outer ring 13a2 of the bearing 13a to be discharged to the side of the turbine impeller 17, from coming into contact with the contact surface 3j1. Thus, the lubricating oil discharged from the bearing 13a to the side of the turbine impeller 17 can be guided smoothly and evenly to the annular groove 43. Furthermore, compared to a case where the inner diameter of the annular groove 43 is larger than the inner diameter of the outer ring 13a2, the contact surface 3j1 has a larger area. Consequently, the outer ring 13a2 can be stably positioned by the contact surface 3j1.

[0060] Fig. Figure 4 is a schematic sectional view of a bearing structure SA according to a modification example. The bearing structure SA according to the modification example differs from the bearing structure S according to the aforementioned embodiment in that a guide section 49 is provided in the connecting passage 45.

[0061] As in Fig. As shown in Figure 4, the bearing structure SA has the guide section 49. The guide section 49 is provided in the connecting passage 45. The guide section 49 directs the lubricating oil, which is discharged through the connecting passage 45, towards the oil discharge port 3c. In the example of Fig. 4. The guide section 49 is provided at a section of the side wall section 3j that faces the connecting passage 45. The guide section 49 projects from a lower end part of the side wall section 3j in the direction of the oil discharge port 3c. In the example of Fig. 4 is the forward direction of the guide section 49, a direction downwards to the right.

[0062] The guide section 49 has a guide surface 49a facing the connecting passage 45. The guide surface 49a extends in a direction perpendicular to both the left and right directions and the top and bottom directions, and extends downwards and to the right, in the direction towards the oil discharge port 3c. After impacting the side wall section 3j, the lubricating oil, which has been discharged from the bearing 13a or the outer circumferential surface of the fitting component 35 to the side of the turbine impeller 17, is delivered to the connecting passage 45 and then guided through the guide surface 49a of the guide section 49 towards the oil discharge port 3c. This design allows the lubricating oil discharged through the connecting passage 45 to be distributed to the oil discharge port 3c. This effectively prevents the lubricating oil from escaping to the side of the turbine impeller 17.

[0063] An embodiment of the present disclosure has been described above with reference to the attached drawings, but it is unnecessary to say that the present disclosure is not limited to the embodiment mentioned above. It is obvious that the person skilled in the art may arrive at various modifications and alterations within the scope of the claims, and these are to be interpreted as naturally falling within the technical scope of the present disclosure.

[0064] For example, in the examples mentioned above, the side wall section 3j, the annular groove 43, and the connecting passage 45 for bearing 13a are formed on the side of the turbocharger TC located near the turbine impeller 17. However, the side wall section 13j, the annular groove 43, and the connecting passage 45 can be designed for a different bearing 13 instead of bearing 13a in the turbocharger TC. This design prevents the escape of lubricating oil to components other than the turbine impeller 17 that are located around the bearing 13.

[0065] For example, in the examples mentioned above, the bearing structure S or SA is provided on the turbocharger TC. However, the bearing structure S or SA can be applied to devices, including rolling bearings, that are different from the turbocharger TC. Reference symbol list 3 bearing housings 3b Bearing hole 3c Oil discharge port 3j side wall section 13a Warehouse 13a1 Inner ring 13a2 Outer ring 13a3 Rolling element 15 wave 35 Fitting component 35d side surface 43 ring-shaped groove 45 Connecting passage 49 Leadership section S storage structure SA warehouse structure TC turbocharger QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2023-066482

[0001] JP 6168739 B2

[0003]

Claims

[1] Warehouse structure with: a wave; a bearing which has an inner ring, an outer ring and rolling elements provided between the inner ring and the outer ring, and which axially supports the shaft; a bearing housing that accommodates the bearing; a side wall section that is formed in the bearing housing and is opposite the rolling elements in an axial direction of the shaft over an entire area in a circumferential direction of the shaft; a ring-shaped groove defined between the side wall section and the bearing, extending in the circumferential direction; an oil discharge port formed in the bearing housing; and a connecting passage that allows the annular groove and the oil discharge port to be connected to each other, and which passes through the bearing housing in a direction that intersects the axial direction. [2] Storage structure according to claim 1, further comprising: a bearing hole formed in the bearing housing; and a fitting component that is provided integrally with or separately from the outer ring and has an outer circumferential surface which is permitted to be fitted to an inner circumferential surface of the bearing bore, wherein the side wall section is opposite an outer circumferential edge of a side surface of the fitting component in the axial direction over the entire area in the circumferential direction. [3] Bearing structure according to claim 1, wherein the annular groove has an inner diameter corresponding to an inner diameter of the outer ring. [4] Bearing structure according to claim 1, further comprising a guide section provided in the connecting passage and guiding lubricating oil that has been discharged through the connecting passage in a direction towards the oil discharge port. [5] Turbocharger with the bearing structure according to one of claims 1 to 4.

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