Supercharging device and method for modifying supercharger

Abstract

Provided is a supercharging device comprising a supercharger, wherein the supercharger includes a compressor impeller, a turbine disk, a rotary shaft connecting the compressor impeller and the turbine disk, and a thrust bearing regulating axial-direction movement of the rotary shaft. The supercharger includes a compressed air supply line for supplying compressed air from outside the supercharger to the back surface of the turbine disk, a lubricating oil supply line for supplying lubricating oil to the thrust bearing, a lubricating oil pump provided in the lubricating oil supply line, and a valve provided in the compressed air supply line. The valve is opened to supply the compressed air from outside the supercharger to the back surface of the turbine disk when a power failure occurs and / or when the pressure of the lubricating oil in the lubricating oil supply line falls below a threshold value.

Description

Supercharger and Method for Modifying a Supercharger

[0001] This disclosure relates to a supercharger and a method for modifying a supercharger. This application claims priority based on Japanese Patent Application No. 2024-198754 filed with the Japan Patent Office on November 14, 2024, the content of which is incorporated herein by reference.

[0002] Generally, lubricating oil is supplied to the bearings of a supercharger using a lubricating oil pump. However, for example, when a power outage occurs (assuming a marine supercharger, when the ship's internal power supply is lost), the operation of the lubricating oil pump stops.

[0003] On the other hand, the engine connected to the supercharger may continue to operate in anticipation of a power outage being resolved in a short time even when a power outage occurs. In such a case, the state where the exhaust gas of the engine is supplied to the supercharger continues. Therefore, a strong thrust load is applied to the thrust bearing on the compressor side of the supercharger with insufficient supply of lubricating oil to the bearings, and there is a concern that the thrust bearing may be damaged.

[0004] Patent Document 1 discloses a supercharger configured to provide a lubricating oil tank above the supercharger and continue supplying lubricating oil from the lubricating oil tank to the thrust bearing even when the operation of the lubricating oil pump stops.

[0005] Japanese Patent No. 6503586

[0006] However, in the supercharger of Patent Document 1, even if the supply of lubricating oil from the lubricating oil tank to the thrust bearing is continued when the operation of the lubricating oil pump stops, the supply of lubricating oil to the thrust bearing is performed by the weight of the lubricating oil. Therefore, it is difficult to obtain a lubricating oil pressure sufficient to protect the thrust bearing, and there still remains a risk of damage to the thrust bearing.

[0007] In view of the above circumstances, at least one embodiment of the present disclosure aims to provide a supercharger and a method for modifying a supercharger that can reduce the risk of damage to the thrust bearing in at least one of the cases where a power outage occurs and the supply pressure of lubricating oil to the thrust bearing decreases.

[0008] To achieve the above objective, a supercharger according to at least one embodiment of the present disclosure is a supercharger comprising a supercharger, the supercharger comprising: a compressor impeller; a turbine disk; a rotating shaft connecting the compressor impeller and the turbine disk; and a thrust bearing restricting the axial movement of the rotating shaft, the supercharger comprising: a compressed air supply line for supplying compressed air from outside the supercharger to the back of the turbine disk; a lubricating oil supply line for supplying lubricating oil to the thrust bearing; a lubricating oil pump provided in the lubricating oil supply line; and a valve provided in the compressed air supply line, the supercharger is configured to open the valve and supply compressed air from outside the supercharger to the back of the turbine disk in at least one of the following cases: when a power outage occurs and when the pressure of the lubricating oil in the lubricating oil supply line falls below a threshold.

[0009] According to at least one embodiment of the present disclosure, with respect to a supercharger, and with respect to a supercharger equipped with a supercharger, a supercharger and a method for modifying a supercharger are provided that can reduce the risk of damage to the thrust bearing in at least one of the cases of a power outage and a decrease in the supply pressure of lubricating oil to the thrust bearing.

[0010] This is a schematic configuration diagram of a supercharger 2 according to one embodiment of the present disclosure. This is a schematic diagram showing a modified example of the supercharger 2. This is a view of the vacuum breaker 73 from the downstream side in the axial direction of the outer pipe 77.

[0011] Hereinafter, several embodiments of this disclosure will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative arrangements, etc., of the components described as embodiments or shown in the drawings are not intended to limit the scope of the invention, but are merely illustrative examples. For example, expressions describing relative or absolute arrangements such as "in a certain direction," "along a certain direction," "parallel," "orthogonal," "center," "concentric," or "coaxial" should not only strictly represent such arrangements, but also represent states where there is a tolerance, or a relative displacement of an angle or distance sufficient to achieve the same function. For example, expressions describing things as being in an equal state such as "identical," "equal," and "homogeneous" should not only strictly represent states of equality, but also represent states where there is a tolerance, or a difference sufficient to achieve the same function. For example, expressions describing shapes such as a square shape or a cylindrical shape should not only represent geometrically precise shapes such as square shapes or cylindrical shapes, but also represent shapes including concave and concave parts, chamfered parts, etc., to the extent that the same effect can be achieved. On the other hand, expressions such as "to possess," "to be equipped with," "to have," "to include," or "to have" a single component are not exclusive expressions that exclude the existence of other components.

[0012] Figure 1 is a schematic diagram of a supercharger 2 according to one embodiment. As shown in Figure 1, the supercharger 2 includes a supercharger 3. The supercharger 3 includes a compressor 4, a turbine 5, a rotating shaft 6 connecting the compressor 4 and the turbine 5, and a bearing device 7 supporting the rotating shaft 6. The supercharger 3 may be, for example, a marine supercharger. In the illustrated example, the compressor 4 is a centrifugal compressor and the turbine 5 is an axial flow turbine. Hereinafter, the radial direction of the rotating shaft 6 will be simply referred to as "radial direction," the axial direction of the rotating shaft 6 will be simply referred to as "axial direction," and the circumferential direction of the rotating shaft 6 will be simply referred to as "circumferential direction."

[0013] The compressor 4 is equipped with a compressor impeller 8, which includes a substantially frustoconical compressor disc 10 and a plurality of compressor blades 12 provided on the outer surface of the compressor disc 10 at circumferential intervals.

[0014] The turbine 5 is equipped with a turbine wheel 9, which includes a substantially disc-shaped turbine disk 18 and a plurality of turbine blades 20 arranged circumferentially on the outer surface of the turbine disk 18 at circumferential intervals. The compressor impeller 8 and the turbine disk 18 are connected by a rotating shaft 6 and arranged coaxially. Exhaust gas discharged from an engine (not shown) flows into the plurality of turbine blades 20 from the opposite side of the compressor impeller 8 in the direction F in Figure 1, causing the turbine wheel 9 to rotate. As a result, the compressor impeller 8, which is connected to the turbine wheel 9 via the rotating shaft 6, rotates integrally with the turbine wheel 9, compressing the air. The air (compressed air) that has passed through the compressor impeller 8 passes through a vortex-shaped chamber 19 provided on the outer surface of the compressor impeller 8, and is then supplied to an engine (not shown). The vortex chamber 19 is formed by a part of a casing (stationary wall) (not shown) of the supercharger 3.

[0015] The bearing device 7 includes a pair of journal bearings 22 that rotatably support the rotating shaft 6, and a thrust bearing 24 that restricts the axial movement of the rotating shaft 6. The pair of journal bearings 22 and the thrust bearing 24 are supported by a casing (stationary wall) of the supercharger 3 (not shown).

[0016] A pair of journal bearings 22 are arranged with an axial gap between them. In the illustrated exemplary embodiment, a thrust bearing 24 is configured to receive an axial thrust load L from the rotating shaft 6 via an annular thrust collar 26 fixed to the outer circumferential surface of the rotating shaft 6, and includes a pair of stationary disks 28 (thrust bearings) arranged to sandwich the thrust collar 26. One of the pair of stationary disks 28 is positioned on one side axially relative to the thrust collar 26, and the other of the pair of stationary disks 28 is positioned on the other side axially relative to the thrust collar 26. In the illustrated exemplary embodiment, when the supercharger 3 is in operation, the engine exhaust gas flows into the plurality of turbine blades 20 from the opposite side of the compressor impeller 8 in the direction F in Figure 1, and a thrust load L is applied to the stationary disks 28 between the thrust collar 26 and the compressor impeller 8 in a direction that biases toward the compressor impeller 8.

[0017] As shown in Figure 1, the supercharger 2 includes a lubricating oil supply line 30, a lubricating oil pump 32, a lubricating oil tank 34, and a pressure sensor 36. The lubricating oil supply line 30 is configured to supply lubricating oil to the bearing device 7 from outside the supercharger 3. The lubricating oil pump 32 is provided in the lubricating oil supply line 30 and is configured to pump the lubricating oil. The lubricating oil tank 34 is provided downstream of the lubricating oil pump 32 in the lubricating oil supply line 30 and is configured to store the lubricating oil supplied by the lubricating oil pump 32. The lubricating oil tank 34 is provided, for example, on top of the supercharger 3, and the lubricating oil stored in the lubricating oil tank 34 is supplied to the pair of journal bearings 22 and thrust bearings 24 by its own weight.

[0018] In the illustrated exemplary configuration, the lubricating oil supply line 30 branches downstream of the lubricating oil tank 34 and supplies lubricating oil to a pair of journal bearings 22 and thrust bearings 24. In this case, a portion of the lubricating oil supply line 30 is formed by a conduit provided outside the casing (not shown) of the turbocharger 3, and the remainder of the lubricating oil supply line 30 is formed by an internal flow path formed inside the casing of the turbocharger 3.

[0019] The pressure sensor 36 is configured to measure the pressure of the lubricating oil in the lubricating oil supply line 30. In the illustrated exemplary embodiment, the pressure sensor 36 is located between the lubricating oil pump 32 and the lubricating oil tank 34 in the lubricating oil supply line 30, but the location of the pressure sensor 36 is not limited to this. The pressure sensor 36 may also be positioned at the same height as the axis of the turbocharger 3 (the axis of the rotation shaft 6). This reduces the influence of head pressure and allows for accurate measurement of the lubricating oil pressure.

[0020] Furthermore, as shown in Figure 1, the supercharger 2 includes a compressed air storage tank 40, a compressed air supply line 42, a solenoid valve 44, a check valve 46, a connection line 48, a check valve 49, and a control device 50.

[0021] The compressed air storage tank 40 is located outside the supercharger 3 and stores compressed air. The compressed air stored in the compressed air storage tank 40 may be starting air for starting an engine (not shown) connected to the supercharger 3, or, if the supercharger 3 is a marine supercharger, it may be general-purpose air used on board the ship.

[0022] The compressed air supply line 42 is configured to supply compressed air from outside the turbocharger 3 to the back surface 18a of the turbine disk 18. In the illustrated exemplary embodiment, the compressed air supply line 42 supplies compressed air stored in the compressed air storage tank 40 to the back surface 18a of the turbine disk 18. In this case, a portion of the compressed air supply line 42 may be configured as a conduit provided outside the casing (not shown) of the turbocharger 3, and the remainder of the compressed air supply line 42 may be configured as an internal flow path formed inside the casing of the turbocharger 3.

[0023] The solenoid valve 44 is installed in the compressed air supply line 42. In this embodiment, the solenoid valve 44 is a normally open type solenoid valve, and is in an open state when the solenoid valve 44 is not energized (when no current flows through the solenoid coil (not shown) provided in the solenoid valve 44), and is in a closed state when the solenoid valve 44 is energized (when current flows through the solenoid coil (not shown) provided in the solenoid valve 44).

[0024] The connection line 48 connects the vortex chamber 19 to a position P1 downstream of the solenoid valve 44 in the compressed air supply line 42. Here, the connection line 48 and the portion 42A downstream of the position P1 in the compressed air supply line 42 that connects to the connection line 48 are formed by an internal passage 60 formed inside the casing (not shown) of the turbocharger 3, and the portion 42B upstream of the position P1 in the compressed air supply line 42 that connects to the connection line 48 are formed by a pipeline provided outside the casing (not shown) of the turbocharger 3. When the turbocharger 3 is in operation, compressed air generated by the compressor impeller 8 is supplied from the vortex chamber 19 through the internal passage 60 (i.e., through the connection line 48 and the downstream portion 42A of the compressed air supply line 42) to the back of the turbine disk 18.

[0025] The check valve 46 is located upstream of the connection point P1 with the connection line 48 in the compressed air supply line 42. The check valve 46 is configured to allow compressed air to flow from the compressed air storage tank 40 to the back surface 18a of the turbine disk 18, and to prevent backflow of compressed air from the connection line 48 to the compressed air storage tank 40.

[0026] The check valve 49 is located upstream of the connection point P1 with the compressed air supply line 42 in the connection line 48. The check valve 49 is configured to allow the flow of compressed air from the vortex chamber 19 to the back surface 18a of the turbine disk 18, and to prevent the backflow of compressed air from the compressed air storage tank 40 to the vortex chamber 19.

[0027] The control device 50 controls the solenoid valve 44 such that when the pressure of the lubricating oil in the lubricating oil supply line 30, as measured by the pressure sensor 36, is above a threshold, it energizes the solenoid valve 44 to close it, and when the pressure of the lubricating oil in the lubricating oil supply line 30, as measured by the pressure sensor 36, falls below the threshold, it stops energizing the solenoid valve 44 to open it. For this reason, the normally open type solenoid valve 44 will be open when a power outage occurs (i.e., when the power supply to the supercharger 2 is stopped and the solenoid valve 44 is no longer energized) and when the pressure of the lubricating oil in the lubricating oil supply line 30, as measured by the pressure sensor 36, falls below the threshold, and will be closed when there is no power outage and the pressure of the lubricating oil in the lubricating oil supply line 30, as measured by the pressure sensor 36, is above the threshold. Here, the threshold is set so as to maintain a sufficient amount of lubricating oil supplied from the lubricating oil supply line 30 to the thrust bearing 24 from the viewpoint of suppressing damage to the thrust bearing 24.

[0028] The control device 50 may be composed of an electrical circuit or a computer. When the control device 50 is composed of a computer, it includes a storage device such as RAM (Random Access Memory) or ROM (Read Only Memory) and a processor such as a CPU (Central Processing Unit), and the processor realizes its function by executing a program stored in the storage device.

[0029] Here, we will explain the effects of the supercharger 2 described above. As mentioned above, if a power outage occurs, the operation of the lubricating oil pump 32 will stop, making it difficult to maintain the amount of lubricating oil supplied from the lubricating oil supply line 30 to the thrust bearing 24. In this state, if a thrust load L is applied from the rotating shaft 6 to the thrust bearing 24 in the direction toward the compressor impeller 8, there is a concern that the thrust bearing 24 on the compressor 4 side may be damaged. Furthermore, a similar problem may occur if the pressure of the lubricating oil in the lubricating oil supply line 30 decreases due to some other reason.

[0030] In contrast, with the supercharger 2 described above, in the event of a power outage and when the pressure of the lubricating oil in the lubricating oil supply line 30 falls below a threshold, the solenoid valve 44 provided in the compressed air supply line 42 is opened to supply compressed air to the back surface 18a of the turbine disk 18 from outside the supercharger 3, thereby biasing the turbine disk 18 toward the opposite side of the compressor impeller 8 with the compressed air. As a result, the thrust load L from the rotating shaft 6 to the thrust bearing 24 (thrust load in the direction that biases the thrust bearing 24 toward the compressor impeller 8) can be reduced, and the risk of damage to the thrust bearing 24 can be reduced. As a result, from the viewpoint of reducing the risk of damage to the thrust bearing 24, the dependence on the supply of lubricating oil from the lubricating oil tank 34 to the thrust bearing 24 can be reduced (for example, the supply pressure of lubricating oil from the lubricating oil tank 34 to the thrust bearing 24 can be reduced). As a result, for example, the height of the lubricating oil tank 34 can be reduced, and the design freedom of the lubricating oil tank 34 can be increased.

[0031] Furthermore, with the supercharger 2 described above, if a power outage occurs, the normally open type solenoid valve 44 will be de-energized, causing the solenoid valve 44 to open automatically. As a result, when a power outage occurs, compressed air is automatically supplied from outside the supercharger 3 to the back surface 18a of the turbine disk 18, eliminating the need for complex control circuits and effectively reducing the risk of damage to the thrust bearing 24 due to power outages with a simple configuration.

[0032] Furthermore, the supercharging device 2 includes a check valve 49 provided in the connection line 48 and a check valve 46 provided upstream of the compressed air supply line 42 from the position P1 where the compressed air supply line 42 and the connection line 48 are connected. Therefore, it is possible to prevent backflow of compressed air from the compressed air supply line 42 to the vortex chamber 19 and backflow of compressed air from the vortex chamber 19 to the compressed air storage tank 40.

[0033] Furthermore, when manufacturing the supercharger 2 shown in Figure 1, the supercharger 2 may be manufactured by modifying an existing supercharger 3 equipped with the internal flow path 60 by adding a portion 42B upstream of the position P1 where it connects to the connection line 48 in the compressed air supply line 42.

[0034] In this case, the modification method for the turbocharger 3 includes the steps of connecting one end of the first pipe 70 (pipe constituting part of the compressed air supply line 42) to the internal passage 60 and connecting the other end of the first pipe 70 to the outlet of a normally open type solenoid valve 44, and connecting one end of the second pipe 72 (pipe constituting another part of the compressed air supply line 42) to the inlet of the solenoid valve 44 and connecting the other end of the second pipe 72 to the compressed air storage tank 40. Furthermore, the above modification method for the turbocharger 3 includes the step of installing a check valve 46 at an intermediate position in the second pipe 72.

[0035] According to the turbocharger 3 manufactured by the above-described modification method, in the event of a power outage, the normally open type solenoid valve 44 will be de-energized, causing the solenoid valve 44 to open automatically. Therefore, in the event of a power outage, compressed air is automatically supplied from outside the turbocharger 3 to the back surface 18a of the turbine disk 18, effectively reducing the risk of damage to the thrust bearing 24 with a simple configuration. Furthermore, by performing the above two steps on a modification to an existing turbocharger 3 equipped with an internal passage 60 that supplies compressed air from the vortex chamber 19 to the back surface 18a of the turbine disk 18, a turbocharger 2 capable of reducing the risk of damage to the thrust bearing 24 in the event of a power outage can be easily manufactured.

[0036] Figure 2 is a schematic diagram showing a modified example of the supercharger 2 described above. In the supercharger 2 shown in Figure 2, the reference numerals common to the components of the supercharger 2 shown in Figure 1 indicate the same components as those shown in the supercharger 2 shown in Figure 1, unless otherwise specified, and their explanation is omitted.

[0037] In some embodiments, the supercharger 2 may further include a vacuum breaker 73, as shown in Figure 2, for example. In the exemplary embodiment shown in Figure 2, the vacuum breaker 73 is fixed to the side wall of the bearing base 74 of the supercharger 3 (a casing that houses the thrust bearing 24, etc., in the supercharger 3).

[0038] The vacuum breaker 73 has a double-pipe structure and includes an inner pipe 76 for guiding compressed air from outside the supercharger 3 to the downstream side of the check valve 49 in the internal passage 60, and an outer pipe 77 that covers the inner pipe 76. An opening 78 communicating with the vortex chamber 19 is formed in the side wall of the outer pipe 77. This opening 78 is located upstream of the check valve 49. One end 80 (downstream end) of the outer pipe 77 is divided into two parts, and as shown in Figure 3, when the vacuum breaker 73 is viewed from the downstream side in the axial direction of the outer pipe 77, one end 82 of the inner pipe 76 that opens to the internal passage 60 (see Figure 2) is provided on a part of the one end 80 of the outer pipe 77, and the remaining part of the one end 80 of the outer pipe 77 is provided with a check valve 49 that closes when the pressure at the opening 78 becomes negative (when the pressure in the vortex chamber 19 becomes negative).

[0039] As shown in Figure 2, one end 82 of the inner pipe 76 of the vacuum breaker 73 is connected to the downstream side of the check valve 49 in the internal flow path 60, bypassing the opening 78 in the side wall of the outer pipe 77. The other end 83 of the inner pipe 76 is positioned at the center of the outer pipe 77 on the flange 75 of the vacuum breaker 73, and the one end 82 of the inner pipe 76 that opens into the internal flow path 60 is offset from the center of the outer pipe 77. Therefore, the inner pipe 76 extends inside the outer pipe 77 from the flange 75 side toward the one end 82 side of the inner pipe 76 in a direction inclined with respect to the axis of the outer pipe 77.

[0040] The check valve 49 is closed when the pressure at the opening 78 is negative, and is open when the pressure at the opening 78 is higher than the pressure in the portion 42A downstream of the check valve 49 in the internal flow path 60.

[0041] A flange 86, provided on one end 85 of the first pipe 70 (a pipe that constitutes part of the compressed air supply line 42), is fastened to the flange 75 of the vacuum breaker 73 by a bolt (not shown). By fastening flange 75 and flange 86, the other end 83 of the inner pipe 76 is connected to one end 85 of the first pipe 70. As a result, one end 85 of the first pipe 70 is connected to the downstream side of the check valve 49 in the internal flow path 60 via the inner pipe 76. Therefore, the compressed air introduced from the first pipe 70 is guided directly to the downstream side of the check valve 49 in the internal flow path 60 without passing through the check valve 49 from the inner pipe 76.

[0042] On the other hand, during normal operation of the turbocharger 3 (for example, during rated operation of the turbocharger 3), the pressure of the compressed air introduced from the vortex chamber 19 into the outer tube 77 through the opening 78 of the outer tube 77 (i.e., the pressure of the compressed air in the space formed between the inner circumferential surface of the outer tube 77 and the outer circumferential surface of the inner tube 76) is higher than the pressure downstream of the check valve 49 in the internal flow path 60. As a result, the compressed air introduced from the vortex chamber 19 into the outer tube 77 through the opening 78 pushes open the check valve 49 of the vacuum breaker 73. This causes the compressed air from the vortex chamber 19 to be introduced through the check valve 49 to the downstream side of the check valve 49 in the internal flow path 60 and supplied to the back surface 18a of the turbine disk 18.

[0043] In the supercharger 2 shown in FIG. 2, for the existing supercharger 3 provided with a vacuum breaker 73, one end 85 of the first pipe 70 is connected to the other end 83 of the inner pipe 76 by fastening the flange 75 of the vacuum breaker 73 and the flange 86 of the first pipe 70, the other end of the first pipe 70 is connected to the outlet of the solenoid valve 44, one end of the second pipe 72 is connected to the inlet of the solenoid valve 44, and the other end of the second pipe 72 is connected to the compressed air storage tank 40. Thus, the existing supercharger 3 can be modified to easily manufacture the supercharger 2. Therefore, for the supercharger 3 provided with the vacuum breaker 73, a supercharger 2 capable of reducing the risk of damage to the thrust bearing 24 in case of a power failure can be easily manufactured. Further, by providing the vacuum breaker 73, it is possible to prevent the bearing lubricating oil from being sucked into the vortex chamber 19 which becomes negative pressure during engine startup or during low engine load. In addition, if it is a modification method that does not use the vacuum breaker 73, a process of providing a through hole for connecting the compressed air supply line 42 to the bearing pedestal 74 newly becomes necessary.

[0044] The present disclosure is not limited to the above-described embodiments, and includes forms obtained by modifying the above-described embodiments and forms obtained by appropriately combining these forms.

[0045] For example, in the embodiment described above, the supercharger 2 was configured to open a solenoid valve 44 provided in the compressed air supply line 42 to supply compressed air to the back surface 18a of the turbine disk 18 from outside the supercharger 3 in the event of a power outage and in the event that the pressure of the lubricating oil in the lubricating oil supply line 30 falls below a threshold. However, the supercharger 2 only needs to be configured to open a solenoid valve 44 provided in the compressed air supply line 42 to supply compressed air to the back surface 18a of the turbine disk 18 from outside the supercharger 3 in at least one of the events of a power outage and in the event that the pressure of the lubricating oil in the lubricating oil supply line 30 falls below a threshold. In other words, the supercharger 2 may be configured to open a solenoid valve 44 provided in the compressed air supply line 42 and supply compressed air to the back surface 18a of the turbine disk 18 from outside the supercharger 3 only when a power outage occurs, or it may be configured to open a solenoid valve 44 provided in the compressed air supply line 42 and supply compressed air to the back surface 18a of the turbine disk 18 from outside the supercharger 3 only when the pressure of the lubricating oil in the lubricating oil supply line 30 falls below a threshold.

[0046] The contents described in each of the above embodiments can be understood, for example, as follows:

[0047] [1] The supercharger according to at least one embodiment of the present disclosure is a supercharger (e.g., the supercharger 2 described above) including a supercharger (e.g., the supercharger 3 described above), and the supercharger includes: a compressor impeller (e.g., the compressor impeller 8 described above); a turbine disk (e.g., the turbine disk 18 described above); a rotating shaft (e.g., the rotating shaft 6 described above) connecting the compressor impeller and the turbine disk; and a thrust bearing (e.g., the thrust bearing 24 described above) that restricts axial movement of the rotating shaft. The supercharger further includes a compressed air supply line (e.g., the compressed air supply line 42 described above) for supplying compressed air from the outside of the supercharger to the back surface of the turbine disk, a lubricating oil supply line (e.g., the lubricating oil supply line 30 described above) for supplying lubricating oil to the thrust bearing, a lubricating oil pump (e.g., the lubricating oil pump 32 described above) provided in the lubricating oil supply line, and a valve (e.g., the solenoid valve 44 described above) provided in the compressed air supply line. The supercharger is configured to open the valve and supply the compressed air from the outside of the supercharger to the back surface of the turbine disk at least when a power failure occurs or when the pressure of the lubricating oil in the lubricating oil supply line drops below a threshold value.

[0048] As described above, when a power failure occurs, the operation of the lubricating oil pump stops, making it difficult to maintain the supply amount of lubricating oil from the lubricating oil supply line to the thrust bearing. In such a state, if a thrust load in the direction from the rotating shaft to the thrust bearing toward the compressor impeller side is applied, there is a concern that the thrust bearing may be damaged. The same problem may also occur when the pressure of the lubricating oil in the lubricating oil supply line decreases due to some other cause.

[0049] In contrast, with the supercharger described in [1] above, in at least one of the following cases, a valve provided in the compressed air supply line is opened to supply compressed air to the back of the turbine disk from outside the supercharger, thereby biasing the turbine disk toward the opposite side of the compressor impeller with compressed air. This reduces the thrust load from the rotating shaft toward the compressor impeller to the thrust bearing in at least one of the following cases: when a power outage occurs or when the supply pressure of lubricating oil to the thrust bearing decreases, thereby reducing the risk of damage to the thrust bearing.

[0050] [2] In some embodiments, in the supercharging device described in [1] above, the valve is a normally open type solenoid valve.

[0051] According to the supercharging system described in [2] above, in the event of a power outage, the normally open type solenoid valve will be unpowered, causing the solenoid valve to open automatically. Therefore, in the event of a power outage, compressed air is automatically supplied from outside the supercharger to the back of the turbine disk, effectively reducing the risk of thrust bearing damage caused by power outages with a simple configuration.

[0052] [3] In some embodiments, the supercharger described in [1] or [2] above further comprises: a pressure sensor (for example, the pressure sensor 36 described above) for measuring the pressure of the lubricating oil in the lubricating oil supply line; and a control device (for example, the control device 50 described above) configured to open the valve when the pressure measured by the pressure sensor falls below a threshold.

[0053] According to the supercharging system described in [3] above, even if the pressure of the lubricating oil in the lubricating oil supply line falls below a threshold due to any reason other than a power outage, the thrust load from the rotating shaft toward the compressor impeller can be reduced by opening a valve provided in the compressed air supply line and supplying compressed air to the back of the turbine disk from outside the supercharger, thereby reducing the thrust load toward the compressor impeller from the rotating shaft toward the thrust bearing, and thus reducing the risk of damage to the thrust bearing.

[0054] [4] In some embodiments, the supercharger described in any of [1] to [3] above, the supercharger includes a tank for storing compressed air (for example, the compressed air storage tank 40 described above), and the compressed air supply line is configured to supply the compressed air stored in the tank to the back surface of the turbine disk.

[0055] According to the supercharging system described in [4] above, the risk of damage to the thrust bearing can be reduced by utilizing the compressed air stored in the tank. The compressed air stored in this tank may be starting air used to start the engine connected to the supercharger, or, if the supercharger is a marine supercharger, it may be general-purpose air used on board the ship.

[0056] [5] In some embodiments, the supercharger described in any of [1] to [4] above further comprises: a vortex chamber provided on the outer circumference of the compressor impeller (for example, the vortex chamber 19 described above); and a connecting line (for example, the connecting line 48 described above) connecting the vortex chamber to a position downstream of the valve in the compressed air supply line (for example, the position P1 described above).

[0057] According to the supercharging system described in [5] above, compressed air can be supplied from the vortex chamber to the back of the turbine disk when the supercharger is in operation. Furthermore, since the connecting line is located downstream of the valve in the compressed air supply line, for example, when there is no power outage and the pressure in the lubricating oil supply line is not below the threshold, the valve can be kept closed to prevent backflow of compressed air from the vortex chamber to the upstream side of the valve in the compressed air supply line (the tank side where compressed air is stored).

[0058] [6] In some embodiments, the supercharging device described in [5] further comprises: a first check valve (for example, the check valve 49 described above) provided in the connection line; and a second check valve (for example, the check valve 46 described above) provided upstream of the compressed air supply line from the point where the compressed air supply line and the connection line are connected.

[0059] According to the supercharging device described in [6] above, it is possible to prevent backflow of compressed air from the compressed air supply line to the vortex chamber side and backflow of compressed air from the vortex chamber to the upstream side of the second check valve in the compressed air supply line (the tank side for storing compressed air).

[0060] [7] A method for modifying a supercharger according to at least one embodiment of the present disclosure, wherein the supercharger comprises: a compressor impeller (for example, the compressor impeller 8 described above); a turbine disk (for example, the turbine disk 18 described above); a rotating shaft (for example, the rotating shaft 6 described above) connecting the compressor impeller and the turbine disk; a vortex chamber (for example, the vortex chamber 19 described above) provided on the outer circumference side of the compressor impeller; and an internal passage (for example, the internal passage 60 described above) for supplying compressed air from the vortex chamber to the back of the turbine disk, wherein the modification method comprises: connecting one end of a first pipe (for example, the first pipe 70 described above) to the internal passage and connecting the other end of the first pipe to the outlet of a normally open type solenoid valve (for example, the solenoid valve 44 described above); and connecting one end of a second pipe (for example, the second pipe 72 described above) to the inlet of the solenoid valve and connecting the other end of the second pipe to a tank for storing compressed air (for example, the compressed air storage tank 40 described above).

[0061] According to the turbocharger manufactured by the turbocharger modification method described in [7] above, in the event of a power outage, the normally open type solenoid valve will be unpowered, causing the solenoid valve to open automatically. Therefore, in the event of a power outage, compressed air is automatically supplied from outside the turbocharger to the back of the turbine disk, thus reducing the risk of thrust bearing damage with a simple configuration. Furthermore, by performing the above two steps on a modification to an existing turbocharger equipped with an internal passage for supplying compressed air from the vortex chamber to the back of the turbine disk, a turbocharger capable of reducing the risk of thrust bearing damage in the event of a power outage can be easily manufactured.

[0062] [8] In some embodiments, in the method for modifying a supercharger described in [7] above, the supercharger is equipped with a vacuum breaker (for example, the vacuum breaker 73 described above), the vacuum breaker is equipped with an inner pipe (for example, the inner pipe 76 described above) for guiding compressed air from outside the supercharger into the internal passage, and an outer pipe (for example, the outer pipe 77 described above) covering the inner pipe, an opening (for example, the opening 78 described above) communicating with the vortex chamber is formed on the side of the outer pipe, one end of the outer pipe is connected to the internal passage, a part of the one end of the outer pipe is provided with an end of the inner pipe that opens into the internal passage, the remainder of the one end of the outer pipe is provided with a check valve (for example, the check valve 49 described above) that closes when the pressure at the opening becomes negative, and in the step of connecting one end of the first pipe to the internal passage, one end of the first pipe is connected to the other end of the inner pipe.

[0063] According to the turbocharger modification method described in [8] above, a turbocharger equipped with the vacuum breaker can be easily manufactured that reduces the risk of thrust bearing damage in the event of a power outage. Furthermore, by incorporating a vacuum breaker, it is possible to prevent bearing lubricating oil from being drawn into the vortex chamber when the engine is running or under low engine load, as negative pressure is generated. If the modification method does not utilize a vacuum breaker, it will be necessary to create a through-hole in the bearing base to connect the compressed air supply line.

[0064] 2. Supercharger 3. Supercharger 4. Compressor 5. Turbine 6. Rotating shaft 7. Bearing device 8. Compressor impeller 9. Turbine wheel 10. Compressor disc 12. Compressor blade 18. Turbine disc 18a (back view) 19. Vortex chamber 20. Turbine blade 22. Journal bearing 24. Thrust bearing 26. Thrust collar 28. Static disc 30. Lubrication oil supply line 32. Lubrication oil pump 34. Lubrication oil tank 36. Pressure sensor 40. Compressed air storage tank 42. Compressed air supply line 42A, 42B section 44. Solenoid valve 46, 49. Check valve 48. Connection line 50. Control device 60. Internal flow path 70. First piping 72. Second piping 73. Vacuum breaker 74. Bearing base 75, 86. Flange 76. Inner pipe 77. Outer pipe 78. Opening 80, 82, 85 One end 83 Other end

Claims

1. A supercharger comprising a supercharger, wherein the supercharger comprises a compressor impeller, a turbine disk, a rotating shaft connecting the compressor impeller and the turbine disk, and a thrust bearing restricting the axial movement of the rotating shaft, and the supercharger comprises a compressed air supply line for supplying compressed air from outside the supercharger to the back of the turbine disk, a lubricating oil supply line for supplying lubricating oil to the thrust bearing, a lubricating oil pump provided on the lubricating oil supply line, and a valve provided on the compressed air supply line, and is configured to open the valve to supply compressed air from outside the supercharger to the back of the turbine disk in at least one of the following cases: when a power outage occurs and when the pressure of the lubricating oil in the lubricating oil supply line falls below a threshold.

2. The supercharging device according to claim 1, wherein the valve is a normally open type solenoid valve.

3. The supercharging device according to claim 1, further comprising: a pressure sensor for measuring the pressure of lubricating oil in the lubricating oil supply line; and a control device configured to open the valve when the pressure measured by the pressure sensor falls below a threshold.

4. The supercharger according to claim 1, wherein the supercharger comprises a tank for storing compressed air, and the compressed air supply line is configured to supply the compressed air stored in the tank to the back surface of the turbine disk.

5. The supercharger according to claim 1, further comprising: a vortex chamber provided on the outer circumference of the compressor impeller; and a connecting line connecting the vortex chamber to a position downstream of the valve in the compressed air supply line.

6. The supercharging device according to claim 5, further comprising: a first check valve provided in the connection line; and a second check valve provided upstream of the compressed air supply line at the point where the compressed air supply line and the connection line are connected.

7. A method for modifying a turbocharger, wherein the turbocharger comprises: a compressor impeller; a turbine disc; a rotating shaft connecting the compressor impeller and the turbine disc; a vortex chamber provided on the outer circumference of the compressor impeller; and an internal passage for supplying compressed air from the vortex chamber to the back of the turbine disc, and the modification method comprises: connecting one end of a first pipe to the internal passage and connecting the other end of the first pipe to the outlet of a normally open type solenoid valve; and connecting one end of a second pipe to the inlet of the solenoid valve and connecting the other end of the second pipe to a tank for storing compressed air.

8. The method for modifying a supercharger according to claim 7, wherein the supercharger is equipped with a vacuum breaker, the vacuum breaker comprises an inner tube for guiding compressed air from outside the supercharger into the internal passage, and an outer tube covering the inner tube, an opening communicating with the vortex chamber is formed on the side of the outer tube, one end of the outer tube is connected to the internal passage, a part of the one end of the outer tube is provided with one end of the inner tube that opens into the internal passage, the remainder of the one end of the outer tube is provided with a check valve that closes when the pressure at the opening becomes negative, and in the step of connecting one end of the first piping to the internal passage, one end of the first piping is connected to the other end of the inner tube.

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