supercharger

Abstract

A supercharger includes a rotor including a compressor impeller, a bearing rotatably supporting the rotor, and a bearing housing housing the bearing. The bearing housing is formed with a cooling space formed on a back surface side of the compressor impeller, a bearing housing space housing the bearing, a lubricating oil flow path communicating the cooling space with the bearing housing space for transporting lubricating oil from the cooling space to the bearing housing space, and a lubricating oil supply port formed on an outer surface of the bearing housing and communicating with the cooling space. The supercharger further includes a lubricating oil supply line configured to transport lubricating oil from outside the supercharger to the cooling space through the lubricating oil supply port.

Description

Technical Field

[0001] This invention relates to a booster equipped with a centrifugal compressor. Background Technology

[0002] Internal combustion engines (e.g., motors) may be equipped with turbochargers to increase output. Turbochargers include exhaust turbine turbochargers, which are configured such that exhaust gases from the internal combustion engine rotate a turbine rotor, thereby rotating a compressor impeller (hereinafter referred to as the impeller) and compressing the gas (e.g., combustion air) supplied to the internal combustion engine. As an exhaust turbine turbocharger, a centrifugal compressor is known to deliver the aforementioned gas supplied to the impeller radially outwards, orthogonal to the impeller's axis of rotation.

[0003] In recent years, with the increasing output of internal combustion engines, there has been a demand for higher pressure ratios in centrifugal compressors. To achieve this, the impeller's rotational speed has been increased. However, increasing the impeller's rotational speed leads to greater internal stress due to the centrifugal force generated by rotation. Furthermore, the temperature of the gas compressed by the impeller increases, and this high-temperature gas leaks into the space facing the back of the impeller, further heating it and causing it to become extremely hot. Impellers exposed to such high temperatures and pressures are at risk of reduced high-temperature creep strength and shortened lifespan.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2014-111905

[0007] Patent Document 2: Japanese Patent No. 6246847

[0008] Patent Document 3: Japanese Patent No. 3606293

[0009] The technical problem that the invention aims to solve

[0010] Conventionally, the impeller is cooled by supplying cooling air to the space facing the back of the compressor (see, for example, Patent Document 1). The cooling air used is combustion air that has been compressed by a centrifugal compressor and passed through an intercooler. In this case, a portion of the combustion air compressed by the centrifugal compressor is not supplied to the internal combustion engine, which may lead to a decrease in the overall efficiency of the internal combustion engine system.

[0011] In addition, the gas in the space facing the back of the impeller is cooled indirectly by supplying lubricating oil to the space formed on the back side of the impeller in the housing containing the impeller (for example, see Patent Documents 2 and 3). The lubricating oil supplied to the space formed on the back side of the impeller is discharged directly to the outside of the housing. Summary of the Invention

[0012] In view of the above, at least one embodiment of the present invention aims to provide a turbocharger capable of cooling the back side of a compressor impeller and improving the efficiency of an internal combustion engine system.

[0013] Technical means for solving technical problems

[0014] The booster according to the present invention comprises: a rotor including a compressor impeller, a bearing supporting the rotor for rotatability, and a bearing housing housing the bearing, characterized in that,

[0015] The bearing platform is formed as follows:

[0016] A cooling space is formed on the back side of the compressor impeller;

[0017] A bearing housing space that houses the bearing;

[0018] A lubricating oil flow path that connects the cooling space and the bearing housing space for supplying lubricating oil from the cooling space to the bearing housing space; and

[0019] A lubricating oil supply port is formed on the outer surface of the bearing housing and communicates with the cooling space.

[0020] The turbocharger also includes a lubricating oil supply line, which is configured to supply lubricating oil from the outside of the turbocharger to the cooling space through the lubricating oil supply port.

[0021] The effects of the invention

[0022] According to at least one embodiment of the present invention, a turbocharger is provided that can cool the back side of a compressor impeller and improve the efficiency of an internal combustion engine system. Attached Figure Description

[0023] Figure 1 This is an explanatory diagram illustrating the structure of an internal combustion engine system equipped with a turbocharger according to an embodiment of the present invention.

[0024] Figure 2 It is pulled out Figure 1 The diagram shows a schematic cross-sectional view of the turbocharger, represented by part A.

[0025] Figure 3 This is a schematic cross-sectional view of a turbocharger according to an embodiment of the present invention, showing the equivalent of pulling out... Figure 1 The diagram shows a partial schematic cross-sectional view of the turbocharger, represented by part A.

[0026] Figure 4 It is used for explanation Figure 2 A diagram illustrating the lubrication system within the turbocharger.

[0027] Figure 5 It is used for explanation Figure 2 A diagram illustrating a modified example of the lubrication system within the turbocharger.

[0028] Figure 6 It is used for explanation Figure 3 A diagram illustrating the lubrication system within the turbocharger. Detailed Implementation

[0029] Hereinafter, several embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, and relative arrangements of the constituent components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0030] For example, terms such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" indicate relative or absolute configurations. They do not mean that the configuration is strictly like this, but rather that there are tolerances or that the relative displacement is achieved by angle or distance to the extent that the same function can be obtained.

[0031] For example, terms like "same," "equivalent," and "equal" indicate that things are in an equal state, but they do not necessarily mean a strictly equal state. They also indicate a difference in degree, such as the existence of tolerances or the degree to which the same function can be obtained.

[0032] For example, the expressions for shapes such as quadrilaterals and cylinders, in addition to referring to the geometrically strict meaning of quadrilaterals and cylinders, also indicate shapes that include concave and convex parts, chamfered parts, etc., within the range that can achieve the same effect.

[0033] On the other hand, expressions such as “possess,” “include,” or “have” are not exclusive expressions that exclude the existence of other constituent elements.

[0034] Furthermore, the same symbols may be used to label the same structures and the explanations may be omitted.

[0035] (Turbocharger, internal combustion engine system)

[0036] Figure 1This is an explanatory diagram illustrating the structure of an internal combustion engine system equipped with a turbocharger according to an embodiment of the present invention. Figure 2 It is pulled out Figure 1 The diagram shows a schematic cross-sectional view of the turbocharger, represented by part A. Figure 3 This is a schematic cross-sectional view of a turbocharger according to an embodiment of the present invention, showing the equivalent of pulling out... Figure 1 The diagram shows a partial schematic cross-sectional view of the turbocharger, represented by part A. Figure 1 and the following Figures 2-6 In each of the figures, the up and down directions correspond to the vertical direction, and the top direction corresponds to the top of the vertical direction.

[0037] like Figure 1 As shown, the turbocharger 10 according to several embodiments includes: a rotor 3 comprising a compressor impeller 2 (hereinafter simply referred to as impeller 2), a bearing 4 configured to support the rotor 3 for rotation, and a bearing housing 7 configured to house the bearing 4. The turbocharger 10 can be applied to turbochargers for marine engines, turbochargers for land-based power generation engines, etc. Furthermore, the turbocharger 10 can also be applied to turbochargers for automobiles that are smaller than turbochargers for marine engines.

[0038] The following, for example Figure 1 As shown, the direction in which the axis CA of the booster 10 extends is defined as the axial direction X, and the direction orthogonal to the axis CA is defined as the radial direction Y. The side of the intake port 61 in the axial direction X relative to the impeller 2 (left side in the figure) is defined as the front side XF, and the side opposite to the intake port 61 (right side in the figure) is defined as the rear side XR.

[0039] In the illustrated embodiment, the rotor 3 includes: a rotating shaft 31 having a long side along the axial direction X; an impeller 2 mechanically connected to the front end 311 (XF) of the rotating shaft 31; and a turbine 32 mechanically connected to the rear end 312 (XR) of the rotating shaft 31. The impeller 2 and the turbine 32 are arranged coaxially. Figure 1 As shown, the impeller 2 is disposed in a supply line 12 that supplies gas (e.g., combustion gas such as air) to an internal combustion engine 11 (e.g., an engine). The turbine 32 is disposed in an exhaust line 13 that supplies exhaust gas from the internal combustion engine 11. The internal combustion engine system 1 includes: a turbocharger 10, an internal combustion engine 11, a supply line 12, an exhaust line 13, and an intercooler 14.

[0040] In the illustrated embodiment, the turbocharger 10 further includes a compressor housing 6 and a turbine housing 8. The compressor housing 6 is configured to house the impeller 2 for rotation, and the turbine housing 8 is configured to house the turbine 32 for rotation. A bearing housing 7 is disposed between the compressor housing 6 and the turbine housing 8, and is mechanically connected to the compressor housing 6 and the turbine housing 8, for example, by fastening components such as bolts.

[0041] The turbocharger 10 rotates the turbine 32 by drawing exhaust gas from the internal combustion engine 11 into the turbine housing 8 through the exhaust line 13. The impeller 2 is mechanically connected to the turbine 32 via a rotating shaft 31, and thus rotates integrally with the turbine 32. The turbocharger 10 compresses the gas drawn into the compressor housing 6 through the supply line 12 and delivers it to the internal combustion engine 11 by rotating the impeller 2. The compressed gas is cooled by an intercooler 14 located between the impeller 2 and the internal combustion engine 11 in the supply line 12 before being supplied to the internal combustion engine 11.

[0042] The impeller 2 has a hub 21 and a plurality of impeller blades 23 disposed on the outer surface 22 of the hub 21. The hub 21 is mechanically fixed to the end 311 of the front side XF of the rotating shaft 31. Therefore, the hub 21 and the plurality of impeller blades 23 can rotate integrally with the rotating shaft 31 about the axis CA of the booster 10. In the illustrated embodiment, the impeller 2 is configured as a centrifugal impeller, which is configured to guide the gas delivered from the front side XF in the axial direction X to the outer side in the radial direction Y.

[0043] The compressor housing 6 has an intake port 61 for introducing gas from the outside of the compressor housing 6 and an outlet (not shown) for discharging gas that has passed through the impeller to the outside of the compressor housing and sending it to the internal combustion engine. The turbine housing 8 has an exhaust gas inlet (not shown) for introducing exhaust gas into the inside of the turbine housing 8 and an exhaust gas outlet 81 for discharging the exhaust gas after rotating the turbine 32 to the outside of the turbine housing 8.

[0044] The compressor housing 6 includes: an intake section 620 forming an intake flow path 62 for guiding gas from the intake port 61 into the interior of the compressor housing 6 into the impeller 2; a shield section 630 having a shield surface 63 that is convexly curved toward the tip 231 of the impeller blades 23 of the impeller 2; and a vortex section 640 forming a vortex flow path 64 that guides gas passing through the impeller 2 to the exterior of the compressor housing 6. The intake flow path 62 and the vortex flow path 64 are respectively formed inside the compressor housing 6.

[0045] In the illustrated embodiment, the compressor housing 6 is configured, by combining with the bearing base 7, to form an impeller chamber 65 that houses the impeller 2 and is rotatable, and a diffuser flow path 66 that guides gas from the impeller 2 into a vortex flow path 64. The aforementioned shroud surface 63 divides the front XF portion of the impeller chamber 65. Figures 1-3 As shown, when the impeller 2 is housed in the impeller chamber 65, a gap 65A is formed between the back surface 24 (the rear XR side surface) of the impeller 2 and the front XF side end face 71 of the bearing platform 7.

[0046] Hereinafter, the upstream side of the gas flowing inside the compressor housing 6 may be referred to simply as the "upstream side" and the downstream side of the gas flow direction may be referred to simply as the "downstream side".

[0047] like Figure 1 As shown, the intake flow path 62 extends along the axial direction X. The intake flow path 62 communicates with the intake port 61 located on its upstream side XF and the inlet side of the impeller chamber 65 located on its downstream side XR. The diffuser flow path 66 extends in a direction intersecting (e.g., orthogonal) the axis CA of the booster 10. The diffuser flow path 66 communicates with the outlet side of the impeller chamber 65 located on the upstream side and the vortex flow path 64 located on the downstream side. The vortex flow path 64 has a vortex shape surrounding the impeller 2 (outer side in the radial Y direction). The vortex flow path 64 communicates with the diffuser flow path 66 located on the upstream side and an outlet (not shown) located on the downstream side.

[0048] Gas introduced into the compressor housing 6 from the intake port 61 flows axially X-rearward XR in the intake flow path 62 and is then sent to the impeller 2 where it is compressed. The gas compressed by the impeller 2 flows radially outward through the diffuser flow path 66 and the vortex flow path 64 in sequence, and is then discharged to the outside of the compressor housing 6 through the outlet (not shown). A portion of the gas compressed by the impeller 2 flows into the aforementioned gap 65A.

[0049] like Figures 1-3 As shown, inside the bearing housing 7, there are a cooling space 72 for lubricating oil, which serves as a cooling medium, to flow to the back surface 24 of the impeller 2, and a bearing housing space 73 for housing the aforementioned bearing 4. The cooling space 72 is formed on the front side XF compared to the bearing housing space 73; in other words, it is formed in the axial direction X between the clearance 65A and the bearing housing space 73.

[0050] In the illustrated implementation, such as Figure 1As shown, the distance D1 between the cooling space 72 and the gap 65A is shorter than the distance D2 between the cooling space 72 and the bearing housing space 73. The cooling space 72 extends circumferentially around the axis CA of the turbocharger 10 and is formed on the outer side in the radial Y direction compared to the bearing housing space 73. Furthermore, the outer peripheral end 721 of the cooling space 72 is located on the outer side in the radial Y direction compared to the trailing edge 25 of the impeller blade 23, and the inner peripheral end 722 of the cooling space 72 is located on the inner side in the radial Y direction compared to the trailing edge 25 of the impeller blade 23. Moreover, the illustrated embodiment represents one example of the lubrication system within the turbocharger 10, and the cooling space 72, bearing housing space 73, lubrication supply flow path 750 (described later), and lubrication flow path 76 constituting this lubrication system are not limited to the structures shown.

[0051] At least one lubricating oil supply port 75 and at least one lubricating oil flow path 76 are formed in the bearing housing 7. The at least one lubricating oil supply port 75 is formed on the externally exposed outer surface 74 and communicates with the cooling space 72. The at least one lubricating oil flow path 76 connects the cooling space 72 with the bearing housing space 73. At least one lubricating oil supply flow path 750 for supplying lubricating oil from the outside to the cooling space 72 is formed inside the bearing housing 7. The lubricating oil supply port 75 is formed at one end of the lubricating oil supply flow path 750, and a communication port 723 communicating with the cooling space 72 is formed at the other end. The lubricating oil flow path 76 has an inlet opening 761 communicating with the cooling space 72 at one end and an outlet opening 762 communicating with the bearing housing space 73 at the other end. Furthermore, the "externally exposed outer surface 74" includes a surface that can be contacted from the outside of the bearing housing 7 in the assembled turbocharger 10, and the lubricating oil supply port 75 can also be formed on such a surface. In addition, in the example shown, lubricating oil is supplied from the upper part of the bearing housing 7 to the interior of the bearing housing 7, but it can also be supplied from the lower part of the bearing housing 7 to the interior of the bearing housing 7.

[0052] like Figure 1As shown, the turbocharger 10 also includes a lubricating oil supply line 9, which is configured to supply lubricating oil from the outside of the bearing housing 7 to the cooling space 72 through a lubricating oil supply port 75. The lubricating oil supply line 9 includes at least a lubricating oil pipe 91 connected to the lubricating oil supply port 75 at one end and a lubricating oil pump 92 located at the other end of the lubricating oil pipe 91. The lubricating oil pump 92 is configured to generate power to pressurize the lubricating oil using electricity. By driving the lubricating oil pump 92, lubricating oil is supplied from the other end of the lubricating oil pipe 91 to one end, and then supplied to the cooling space 72 through the lubricating oil supply port 75. The lubricating oil supplied to the cooling space 72 cools the region 71A of the bearing housing 7, which includes the aforementioned end face 71 compared to the cooling space 72, thereby indirectly cooling the gas present in the aforementioned gap 65A. By cooling the gas present in the gap 65A, heat can be suppressed from being transferred from the gap 65A to the back surface 24 of the impeller 2, thereby suppressing the rise in the metal temperature of the impeller 2 when the booster 10 is driven.

[0053] Lubricating oil in the cooling space 72 is pumped by the lubricating oil pump 92 through the lubricating oil flow path 76 to the bearing housing space 73, thereby supplying the bearing 4 housed in the bearing housing space 73. In the illustrated embodiment, the outlet opening 762 of the lubricating oil flow path 76 is formed on the inner wall surface 731A of the inner wall surface 731 of the bearing housing space 73, facing the outer surface 41 of the bearing 4. The lubricating oil is supplied to the bearing 4 from the outer surface 41 side. Here, the lubricating oil in the cooling space 72 is heated by the gas present in the gap 65A, and its viscosity decreases compared to before heating. As a result, lubricating oil with reduced viscosity is supplied to the bearing 4, thus reducing the friction caused by the viscous resistance of the lubricating oil and suppressing mechanical loss of the bearing 4.

[0054] like Figures 1-3 As shown, the turbocharger 10 according to several embodiments includes the impeller 2, the bearing housing 7, and the lubricating oil supply line 9 described above. The bearing housing 7 has the cooling space 72, the bearing housing space 73, the lubricating oil supply port 75, and the lubricating oil flow path 76 described above.

[0055] According to the above structure, the back surface 24 of the impeller 2 is cooled by lubricating oil supplied to the cooling space 72 through the lubricating oil supply port 75 via the lubricating oil supply line 9, thereby suppressing the temperature rise of the impeller 2. By suppressing the temperature rise of the impeller 2, the centrifugal compressor of the booster 10 can operate at a high pressure ratio.

[0056] Furthermore, according to the above structure, the lubricating oil, which has been heated and its temperature increased in the cooling space 72, flows through the lubricating oil flow path 76 to the bearing housing space 73 that houses the bearing 4. The lubricating oil, whose temperature has increased and viscosity has decreased in the cooling space 72, is supplied to the bearing 4, thereby improving the mechanical efficiency of the bearing 4, and further improving the efficiency of the internal combustion engine system 1 equipped with the turbocharger 10.

[0057] In several implementations, such as Figure 1 As shown, the aforementioned lubricating oil supply line 9 also includes a lubricating oil recovery line 93 configured to deliver the lubricating oil supplied to the aforementioned bearing 4 to the lubricating oil pump 92. In this case, since the internal combustion engine system 1 has a lubricating oil supply line 9 including the lubricating oil recovery line 93, the lubricating oil can be circulated via the lubricating oil supply line 9.

[0058] In several implementations, such as Figure 1 As shown, the aforementioned lubricating oil supply line 9 also includes an oil cooler 94 disposed at one end of the lubricating oil pipe 91 relative to the lubricating oil pump 92 (the lubricating oil supply port 75 side). The oil cooler 94 is configured to cool the lubricating oil passing through it. The lubricating oil is heated and its temperature rises when it circulates within the bearing housing 7. When the temperature of the lubricating oil supplied to the cooling space 72 becomes too high, the cooling performance of the lubricating oil may decrease. According to the above structure, by cooling the lubricating oil supplied from the lubricating oil pipe 91 to the cooling space 72 by the oil cooler 94, the decrease in the cooling performance of the lubricating oil can be suppressed, thereby enabling proper cooling of the back surface 24 of the impeller 2 using the lubricating oil within the cooling space 72.

[0059] Generally, the internal combustion engine system 1, which includes a turbocharger 10 and an internal combustion engine 11, has a lubricating oil circulation system for circulating lubricating oil. The oil cooler 94 described above can also be used in the aforementioned lubricating oil circulation system. In this case, the back surface 24 of the impeller 2 can be adequately cooled without requiring significant modifications to the internal combustion engine system 1.

[0060] Figure 4 It is used for explanation Figure 2 A diagram illustrating the lubrication system within the turbocharger. Figure 5 It is used for explanation Figure 2 A diagram illustrating a modified example of the lubrication system within the turbocharger. Figure 4 , Figure 5 And as will be discussed later Figure 6 The following is a rough representation of the state of the lubrication system inside the turbocharger when viewed from the front side in the axial direction. The lubrication system inside the turbocharger 10 includes a cooling space 72, a bearing housing space 73, and a lubrication flow path 76, etc.

[0061] In several implementations, such as Figure 4, 5 As shown, the cooling space 72 is formed in an annular shape extending circumferentially along the turbocharger 10. At least one communication port 723 and at least one inlet opening 761 are formed on the inner wall surface 720 defining the cooling space 72.

[0062] For example, in Figure 4 In the illustrated embodiment, at least one communication port 723 includes a communication port 723A communicating with one of the two lubricating oil supply ports 75 formed on the bearing housing 7 and a communication port 723B communicating with the other of the two lubricating oil supply ports 75. The two communication ports 723A and 723B are respectively formed on the upper part of the inner wall surface 720 and are located at positions that are circumferentially separated from each other in the turbocharger 10. One communication port 723A is located on one side in the width direction (a direction orthogonal to both the direction extending from the axis CA of the turbocharger 10 and the vertical direction, respectively) (e.g., the left side in the figure), and the other communication port 723B is located on the other side in the same width direction (e.g., the right side in the figure). Additionally, an inlet opening 761 is formed on the lower part of the inner wall surface 720.

[0063] Lubricating oil flowing into the cooling space 72 from one of the connection ports 723A flows downward across one side of the cooling space 72 in the width direction and then flows out through the inlet opening 761 into the lubricating oil flow path 76. Conversely, lubricating oil flowing into the cooling space 72 from the other connection port 723B flows downward across the other side of the cooling space 72 in the width direction and then flows out through the inlet opening 761 into the lubricating oil flow path 76. In this case, the gas present in the aforementioned gap 65A can be cooled by the lubricating oil that fills approximately the entire circumference of the annular cooling space 72 in the circumferential direction.

[0064] In addition, Figure 5 In the illustrated embodiment, at least one communication port 723 includes a communication port 723C formed on the upper part of the inner wall surface 720. Additionally, an inlet opening 761 is formed on the upper part of the inner wall surface 720. The communication port 723C and the inlet opening 761 are respectively formed at positions that are circumferentially separated from each other in the booster 10. The communication port 723C is located on one side of the aforementioned width direction (e.g., the left side in the figure), and the inlet opening 761 is located on the other side of the aforementioned width direction (e.g., the right side in the figure). The bearing platform 7 has a partition wall 79 that encloses a portion of the circumferential cooling space 72. For example, the partition wall 79 is located on the upper part of the cooling space 72, which is the side with a narrower gap between the communication port 723C and the inlet opening 761 in the circumferential direction of the cooling space 72. Lubricating oil flowing into the cooling space 72 from the communication port 723C flows circumferentially past the side opposite to the side with the partition wall 79 in the circumferential direction (the lower part of the cooling space 72) and then flows out from the inlet opening 761 into the lubricating oil flow path 76.

[0065] According to the above structure, by supplying lubricating oil to the annular cooling space 72, the lubricating oil is filled approximately around the entire circumference of the cooling space 72, thus enabling proper cooling of the back surface 24 of the impeller 2 around the entire circumference. In this case, the impeller 2 can be cooled more effectively than when the cooling space 72 is formed only in a portion of the circumference.

[0066] Figure 6 It is used for explanation Figure 3 A diagram illustrating the lubrication system within the turbocharger.

[0067] In several implementations, such as Figure 3 , 6 As shown, the aforementioned cooling space 72 is located above the axis CA of the turbocharger 10.

[0068] For example, such as Figure 6 As shown, in the illustrated embodiment, the cooling space 72 is curved in an upwardly projecting arc shape. The cooling space 72 is not formed below the axis CA of the turbocharger 10. At least one connection port 723 includes a connection port 723D formed in the upper part of the inner wall surface 720. Furthermore, below the connection port 723D of the inner wall surface 720, inlet openings 761 for two lubricating oil flow paths 76 are formed. Each of the two inlet openings 761 is formed at the top (lower end) of the arc-shaped curved cooling space 72. One of the two inlet openings 761 is located on one side in the aforementioned width direction (e.g., the right side in the figure), and the other of the two inlet openings 761 is located on the other side in the aforementioned width direction (e.g., the left side in the figure). Furthermore, the two lubricating oil flow paths 76 can be provided completely independently, or they can merge midway.

[0069] In addition, such as Figure 3 As shown, in the illustrated embodiment, the inlet opening 761 of the lubricating oil flow path 76 is located above its outlet opening 762, and the lubricating oil flow path 76 slopes downward from the inlet opening 761 toward the outlet opening 762.

[0070] As described above, the viscosity of the lubricating oil decreases after the temperature rises in the cooling space 72, thus improving its fluidity. According to the above structure, since the cooling space 72 is located above the axis CA of the turbocharger 10, the lubricating oil can easily flow through the lubricating oil flow path 76 and into the bearing housing space 73 formed in the region containing the axis CA of the turbocharger 10 by its own weight. Furthermore, according to the above structure, compared to the case where the cooling space 72 is formed in an annular shape, the flow distance of the lubricating oil in the cooling space 72 can be shortened. Therefore, the capacity of the lubricating oil pump 92 used for conveying lubricating oil can be miniaturized, thus reducing the manufacturing cost of the internal combustion engine system 1. In addition, since the impeller 2 rotates when driven by the turbocharger 10, a portion of the circumferential portion of the gap 65A facing the back surface 24 of the impeller 2 is cooled by the cooling space 72 formed in a circumferential direction, thereby achieving full circumferential cooling of the back surface 24 of the impeller 2.

[0071] The present invention is not limited to the embodiments described above, but also includes modifications to the embodiments described above, and combinations thereof.

[0072] The contents described in the above-described embodiments should be understood as follows.

[0073] 1) The booster 10 according to at least one embodiment of the present invention includes: a rotor 3 comprising a compressor impeller 2, a bearing 4 supporting the rotor 3 to be rotatable, and a bearing housing 7 housing the bearing 4. In this booster 10,

[0074] The bearing platform 7 is formed as follows:

[0075] Cooling space 72, which is formed on the back side 24 of the compressor impeller 2;

[0076] Bearing housing space 73, which houses the bearing 4;

[0077] A lubricating oil flow path 76, which connects the cooling space 72 and the bearing housing space 73 for supplying lubricating oil from the cooling space 72 to the bearing housing space 73; and

[0078] A lubricating oil supply port 75 is formed on the outer surface 74 of the bearing base 7 and communicates with the cooling space 72.

[0079] The turbocharger 10 also includes a lubricating oil supply line 9, which is configured to supply lubricating oil from the outside of the turbocharger 10 to the cooling space 72 through the lubricating oil supply port 75.

[0080] According to the structure described in 1), by using lubricating oil supplied to the cooling space 72 through the lubricating oil supply port 75 via the lubricating oil supply line 9 to cool the back surface 24 of the impeller 2, the temperature rise of the impeller 2 can be suppressed. By suppressing the temperature rise of the impeller 2, it becomes possible for the centrifugal compressor of the booster 10 to operate at a high pressure ratio.

[0081] Furthermore, according to the structure described in 1) above, the lubricating oil, after being heated in the cooling space 72 and its temperature rises, flows through the lubricating oil flow path 76 to the bearing housing space 73 that houses the bearing 4. Since the lubricating oil, after its temperature rises in the cooling space 72 and its viscosity decreases, is supplied to the bearing 4, the mechanical efficiency of the bearing 4 can be improved, thereby improving the efficiency of the internal combustion engine system 1 equipped with the turbocharger 10.

[0082] 2) In several embodiments, in the booster 10 described in 1) above,

[0083] The cooling space 72 is formed in a ring shape extending circumferentially along the rotor 3.

[0084] According to the structure described in 2), by supplying lubricating oil to the annular cooling space 72, the lubricating oil is filled approximately the entire circumference of the cooling space 72, thus enabling proper cooling of the back surface 24 of the impeller 2 throughout the entire circumference. In this case, the impeller 2 can be cooled more effectively than when the cooling space 72 is formed only in a portion of the circumference.

[0085] 3) In several embodiments, in the booster 10 described in 1) above,

[0086] The cooling space 72 is located above the axis CA of the turbocharger 10.

[0087] As described above, the viscosity of the lubricating oil decreases after the temperature rises in the cooling space 72, thus improving its fluidity. According to the structure in 3) above, since the cooling space 72 is located above the axis CA of the turbocharger 10, the lubricating oil can easily flow through the lubricating oil flow path 76 and into the bearing housing space 73 formed in the region containing the axis CA of the turbocharger 10 by its own weight. Furthermore, according to the structure in 3) above, compared to the case where the cooling space 72 is formed in a ring shape, the flow distance of the lubricating oil in the cooling space 72 can be shortened. Therefore, the capacity of the lubricating oil pump 92 used to transport the lubricating oil is miniaturized, thereby reducing the manufacturing cost of the internal combustion engine system 1.

[0088] Symbol Explanation

[0089] 1. Internal Combustion Engine System

[0090] 2 Impeller

[0091] 21-inch wheels

[0092] 22 Outer surface

[0093] 23 Impeller blades

[0094] 231 Top

[0095] 24 Back

[0096] 25. Trailing edge

[0097] 3 rotors

[0098] 31 Rotating shaft

[0099] 311 Front end

[0100] 312 Rear end

[0101] 32 turbochargers

[0102] 4 bearings

[0103] 41 Outer surface

[0104] 6. Compressor housing

[0105] 61 Intake port

[0106] 62 Inhalation airflow path

[0107] 620 Inhalation Inlet Section

[0108] 63 Protective Surface

[0109] 630 Protective Shield Section

[0110] 64 Vortex Flow Path

[0111] 640 Vortex section

[0112] 65 Impeller Chamber

[0113] 65A clearance

[0114] 66 Diffuser Flow Path

[0115] 7 Bearing Stand

[0116] 71 End face

[0117] Area 71A

[0118] 72 Cooling Space

[0119] 720 inner wall

[0120] 721 Peripheral end

[0121] 722 inner peripheral end

[0122] 723, 723A~723D Connecting Port

[0123] 73 Bearing Reception Space

[0124] 731, 731A inner wall surface

[0125] 74 Outer Surface

[0126] 75 Lubricating oil supply port

[0127] 750 Lubricating Oil Supply Flow Path

[0128] 76 Lubricating oil flow path

[0129] 761 Entrance opening

[0130] 762 Exit Opening

[0131] 79 Next door

[0132] 8. Turbine housing

[0133] 81 Exhaust Gas Discharge Outlet

[0134] 9. Lubricating oil supply line

[0135] 91 Lubricating oil piping

[0136] 92 Lubricating oil pump

[0137] 93 Lubricating oil recovery line

[0138] 94 Oil Cooler

[0139] 10. Supercharger

[0140] 11 Internal Combustion Engine

[0141] 12 Supply Lines

[0142] 13. Drainage circuit

[0143] 14 Intercooler

[0144] CA axis

[0145] X-axis

[0146] XF (axial) front side

[0147] XR (axial) rear side

[0148] Y radial

Claims

1. A booster comprising: a rotor including a compressor impeller, a bearing supporting the rotor for rotatability, and a bearing housing housing the bearing, characterized in that, The bearing platform is formed as follows: A cooling space is formed in a ring shape extending circumferentially along the back side of the compressor impeller; A bearing housing space that houses the bearing; A lubricating oil flow path that connects the cooling space and the bearing housing space for supplying lubricating oil from the cooling space to the bearing housing space; and A lubricating oil supply port is formed on the outer surface of the bearing housing and communicates with the cooling space. The turbocharger also includes a lubricating oil supply line configured to supply lubricating oil from outside the turbocharger to the cooling space through the lubricating oil supply port. The lubricating oil supply port includes: A first lubricating oil supply port is connected to a communication port located on one side of the width direction of the turbocharger, one of two communication ports formed on the inner wall surface defining the cooling space at a position separated from each other in the circumferential direction of the turbocharger. as well as The second lubricating oil supply port is connected to the connecting port located on the other side of the width direction among the two connecting ports. The lubricating oil flow path has an inlet opening formed on the inner wall surface defining the cooling space, for guiding the lubricating oil that has been directed to the cooling space from the first lubricating oil supply port and the second lubricating oil supply port to the lubricating oil flow path.

2. The booster according to claim 1, characterized in that, The first lubricating oil supply port and the second lubricating oil supply port are formed on the upper part of the inner wall surface that defines the cooling space. The lubricating oil flow path has the inlet opening and the outlet opening, the inlet opening being formed at the lower part of the inner wall surface defining the cooling space, and the outlet opening being located above the axis of the turbocharger and communicating with the bearing housing space.

3. The booster according to claim 1, characterized in that, The cooling space is formed only above the axis of the turbocharger and is curved into an upward-convex arc shape. The lubricating oil flow path slopes downward from the inlet opening formed on the inner wall surface defining the cooling space toward the outlet opening formed on the inner wall surface defining the bearing receiving space. The inlet opening and the outlet opening are located below the communication port and above the axis of the booster.

4. The booster according to claim 3, characterized in that, The lubricating oil flow path includes a first lubricating oil flow path and a second lubricating oil flow path. The inlet opening of the first lubricating oil flow path is located on one side of the width direction of the turbocharger, and the inlet opening of the second lubricating oil flow path is located on the other side of the width direction.

5. The turbocharger according to any one of claims 1 to 4, characterized in that, The axial distance between the cooling space and the bearing housed in the bearing housing space is greater than the axial distance between the cooling space and the gap formed between the back surface of the compressor impeller and the end face of the bearing housing.

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