JP2008095650A - Cooling structure of supercharger with electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling structure of a supercharger capable of reliably cooling an electric motor disposed therein. <P>SOLUTION: The cooling structure of the supercharger 1 with an electric motor 60 disposed therein includes a first lubricating oil passage 15 for supplying lubricating oil to bearings 40, 45 of the supercharger 1, and a second lubricating oil passage 16 for supplying lubricating oil for cooling to the electric motor 60. The electric motor is reliably cooled because the second lubricating oil passage for supplying lubricating oil for cooling to the electric motor is disposed separately from the first lubricating oil passage for supplying lubricating oil to the bearings of the supercharger. The cooling structure preferably has the second lubricating oil passage 16 with an on-off valve 51 disposed therein. Further, the cooling structure preferably has a control unit 8 for controlling a flow rate of lubricating oil for cooling by adjusting an opening of the on-off valve 51. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cooling structure for a supercharger (hereinafter referred to as a turbocharger) provided with an electric motor.

  In recent years, the proportion of internal combustion engines equipped with turbochargers is increasing. The turbocharger rotates an impeller on the turbine side with engine exhaust gas. An impeller on the compressor side is fixed coaxially with the rotation shaft of the impeller. Therefore, by rotating the turbine side with exhaust gas, compressed air can be sent to the engine on the compressor side to improve the output. However, when the engine is running at a low speed, that is, when the exhaust gas pressure is low, the amount of exhaust gas hitting the impeller of the turbine is small, or the pressure of the exhaust gas is low and the rotation shaft cannot be rotated at a high rotational speed. is there. For this reason, when the rotational speed is low, such as when the engine is started, the necessary compressed air cannot be sent to the compressor side and a desired output may not be obtained.

  Therefore, there is a proposal of a turbocharger equipped with an electric motor that assists the rotation of the rotating shaft. Thus, with a turbocharger equipped with an electric motor, when the engine speed is low, the electric motor can be driven to rotate the rotating shaft, compress the air with the compressor, and send it to the engine to increase the output. For example, Patent Document 1 proposes a bearing structure for a turbocharger that includes an electric motor (motor) as described above. This bearing structure has proposed a structure provided with a retainer ring that suppresses scattering of lubricating oil to the motor side of a radial bearing (floating bearing). This retainer ring prevents the lubricating oil that lubricates the bearing from flowing out in the direction of the motor, so that the increase in agitation resistance (rotational resistance) caused by the inflow of lubricating oil is suppressed, and the turbocharger rotates smoothly. Can do.

Japanese Patent Laid-Open No. 2005-232998

  By the way, since the rotating shaft of the turbocharger rotates at a high speed, a large amount of heat is generated. Therefore, in the turbocharger in which the electric motor is disposed, it is necessary to consider especially that the electric motor does not excessively increase the temperature. However, since the bearing structure disclosed in Patent Document 1 does not consider the cooling of the electric motor, improvement in this regard is necessary.

  Accordingly, an object of the present invention is to propose a cooling structure for a supercharger that can reliably cool an electric motor disposed therein.

  The object is a cooling structure for a supercharger equipped with an electric motor, wherein a first lubricating oil passage for supplying lubricating oil to a bearing of the supercharger, and a first lubricating oil for supplying cooling oil to the electric motor are provided. This can be achieved by a cooling structure for a supercharger with an electric motor, wherein two lubricating oil passages are provided.

  According to the present invention, the second lubricating oil passage for supplying the lubricating oil for cooling to the electric motor is provided separately from the first lubricating oil passage for supplying the lubricating oil to the bearing of the supercharger. Can be reliably cooled.

  In addition, the electric motor includes a coil winding portion protruding on both sides, and a discharge port of the second lubricating oil passage is provided so as to cool the coil winding portion from both sides, It may be provided with an oil intrusion prevention structure that prevents the cooled lubricating oil from entering between the stator and the rotor. In this case, the coil winding portion can be reliably cooled, and the lubricating oil entering between the stator and the rotor can be suppressed to prevent an increase in stirring resistance.

  The first lubricating oil passage and the second lubricating oil passage are connected to a single lubricating oil supply source, and an opening / closing valve is disposed in the second lubricating oil passage. More preferably. In this case, lubricating oil for cooling can be supplied when necessary. Accordingly, it is possible to prevent the cooling lubricant from flowing unnecessarily, and thus it is possible to prevent the stirring resistance of the electric motor from increasing.

  It is more preferable to further include a control means for adjusting the flow rate of the cooling lubricant by adjusting the opening of the on-off valve. If it does in this way, a suitable quantity of lubricating oil can be poured according to the temperature rising state (heating state) of an electric motor.

  The apparatus may further include first temperature detection means for detecting the temperature of the electric motor, and the control means may control the opening degree of the on-off valve based on the output of the first temperature detection means. . Further, the apparatus further comprises second temperature detection means for detecting the temperature of the exhaust gas supplied to the turbine side of the supercharger, wherein the control means is configured to output the electric motor based on the output of the second temperature detection means. The opening degree of the on-off valve may be controlled by estimating the temperature of the valve.

  ADVANTAGE OF THE INVENTION According to this invention, the cooling structure of the supercharger which can cool the electric motor arrange | positioned inside reliably can be provided.

  Hereinafter, an example as a preferred embodiment according to the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of a turbocharger 1 to which a cooling structure according to an embodiment is applied. FIG. 2 is an enlarged view of a part of FIG. In the following description, the radial direction RD is a radial direction that is perpendicular to the rotation axis of the turbocharger and centered on the rotation axis, and the axial direction AD is a direction along the axis of the rotation axis. .

  The turbocharger 1 has a compressor section 20 formed on one side (left side in FIG. 1) in the axial direction AD, and a turbine section 30 formed on the other side. More specifically, a turbine impeller 31 is integrally formed at the end of the rotating shaft 3 on the turbine unit 30 side, and a plurality of members to be described later are interposed on the end of the compressor unit 20 side. A compressor impeller 21 is fitted and fixed by a nut 25. A compressor housing 22 is provided on the outer periphery of the compressor impeller 21, and a turbine housing 32 is provided on the outer periphery of the turbine impeller 31.

  A bearing housing 10 is disposed between the compressor unit 20 side and the turbine unit 30 side, and a water passage 11 and the like for flowing cooling water are formed in the bearing housing 10. A space is formed inside the bearing housing 10, and a motor 60 serving as an electric motor is disposed in the space. A stator 61 of the motor 60 is fixed to the inner wall of the bearing housing 10, and a rotor 65 is fixed to the rotating shaft 3. The stator 61 and the rotor 65 are substantially at the same position in the axial direction AD, and are opposed to each other with a predetermined gap in the radial direction RD. A coil 62 is wound around the stator 61, and a part of the coil 62 is wound so as to protrude outward from the stator 61. The rotor 65 includes a cylindrical magnet 66 fixed to the rotating shaft 3 and a magnet holding tube 67 provided so as to cover the outer periphery of the magnet 66. When the coil 62 is excited by supplying a predetermined current via a wiring (not shown), the rotating shaft 3 to which the rotor 65 is fixed can be rotated. Therefore, the rotating shaft 3 can be auxiliary driven by supplying current to the coil 62 when necessary.

  Radial bearings 40 and 45 that support the rotary shaft 3 in the radial direction RD are disposed on both sides of the rotor 65. The turbine-side radial bearing 40 includes a radial bearing portion 42, and the radial bearing portion 42 is positioned in the axial direction AD by snap rings 43 arranged on both sides. Lubricating oil is supplied to the back side (upper side in FIG. 1) of the radial bearing portion 42 through an oil passage 15 formed in the bearing housing 10.

  Further, the peripheral structure on the compressor side radial bearing 45 side is slightly different from that on the turbine side. The radial bearing 45 includes a radial bearing portion 46, and a snap ring 43 is disposed on the turbine side of the radial bearing portion 46. On the opposite side, a thrust bearing 70 that receives a load (thrust force) in the axial direction AD is provided. Is provided. Lubricating oil is also supplied from the oil passage 15 to the back side (upper side in FIG. 1) of the radial bearing portion 42.

  An oil passage 15 for supplying lubricating oil to the radial bearing 40 and the radial bearing 45 is connected to an oil tank (not shown) via an oil pump 50. The oil passage 15 is a passage for supplying lubricating oil to smoothly rotate the radial bearing 40 and the radial bearing 45 and serves as a first lubricating oil passage. Oil drain portions 17 and 18 are provided at predetermined positions on the lower end of the bearing housing 10. Accordingly, the dropped lubricating oil is discharged from the lower side of the bearing housing 10 and is collected and circulated in an oil pan of an internal combustion engine (not shown). Since the lubricating oil after lubricating the radial bearing 40 and the radial bearing 45 scatters in the space and adheres to the motor 60, the function of cooling the motor 60 can also be achieved. Oil drain portions 17 and 18 are provided at predetermined positions on the lower end of the bearing housing 10. Accordingly, the dropped lubricating oil is discharged from the lower side of the bearing housing 10 and is collected and circulated in an oil pan of an internal combustion engine (not shown). However, since the lubricating oil that has passed through the radial bearing 40 and the radial bearing 45 is often heated, the expected cooling may not be performed.

  Therefore, the turbocharger 1 of this embodiment is provided with a cooling structure for supplying lubricating oil for cooling the motor 60. This cooling structure is formed as an oil passage 16 serving as a second lubricating oil passage provided in the bearing housing 10 separately from the oil passage 15. The cooling oil flowing through the oil passage 16 can also be used as the lubricating oil supplied to the oil passage 15. The oil passage 16 for supplying the cooling lubricating oil is also connected to the oil pump 50 as in the case of the oil passage 15. Therefore, the cooling oil can flow toward the motor 60 with a simple structure.

  FIG. 2 is an enlarged view of a portion of FIG. 1 so that the discharge port portion of the oil passage 16 can be easily confirmed. In FIG. 2, the bearing housing 10 is hatched so that it can be easily confirmed. As shown in this figure, the coil 62 wound around the stator 61 of the motor 60 protrudes left and right. The oil passage 16 is branched left and right in the bearing housing 10, and the left and right discharge ports 16 DS-R and 16 DS-L are arranged to face both sides of the coil 62. Therefore, it can cool by injecting lubricating oil from both sides of coil 62 (coil winding part).

  The state of the right discharge port 16DS-R is shown enlarged in a circle CR. Near the outlet, a needle (needle-like member) ND that expands the spray is fixedly arranged. Thereby, the lubricating oil LU to be injected can be spread and sprayed on the coil 62. The left discharge port 16DS-L has a similar structure. Therefore, the lubricating oil induced in the cooling oil passage 16 can be sprayed onto the coil 62 for cooling.

  As can be seen in FIG. 2, annular projections projecting outward in the radial direction RD are provided at both ends (turbine side end and compressor side end) of the magnet holding tube 67 disposed on the outer periphery of the rotor 65. 68 is formed. Providing such a protrusion 68 can prevent the lubricating oil LU from entering between the stator 61 and the rotor 65 of the motor 60. If the lubricating oil LU enters between the stator 61 and the rotor 65, agitation resistance is generated by the lubricating oil LU, and mechanical loss increases. On the other hand, in the present embodiment, the protrusion 68 that prevents the lubricant LU from entering the outer side of the rotor 65 is provided, so that the oil that prevents the lubricant 61 from entering between the stator 61 and the rotor 65 is provided. An intrusion prevention structure is provided. Therefore, generation | occurrence | production of the stirring resistance (rotation resistance) when the rotating shaft 3 rotates can be suppressed.

  If the amount of cooling lubricant injected from the oil passage 16 can be adjusted according to the temperature rise state of the turbocharger 1, it is more preferable that the motor 60 can be efficiently cooled. The cooling structure according to the embodiment has the configuration. This configuration will be further described with reference to FIG. FIG. 3 is a block diagram including the configuration around the engine (E / G) 2 to which the turbocharger 1 is applied.

  The intake air TA is supplied to the intake manifold 2TM of the engine 2 through the air cleaner (A / C) 4, the compressor unit 20 of the turbocharger 1, the intercooler (I / C) 5, and the throttle valve 6. On the other hand, the exhaust gas EA generated in the engine 2 is discharged from the exhaust manifold 2EM and is discharged to the outside of the apparatus through the turbine section 30 of the turbocharger 1 and the exhaust purification catalyst 7. Such a configuration is the same as a general one.

  The drive of the engine 2 is controlled by an ECU (Electronic Control Unit) 8. The ECU 8 receives output signals from various sensors such as a crank angle sensor, an accelerator opening sensor, and an exhaust gas temperature sensor in order to detect (monitor) the state of the engine 2. The ECU 8 appropriately controls the driving of the engine 2 based on these output signals. Such a configuration is the same as a general one.

  In the case of the present embodiment, the ECU 8 is configured to function also as a control means for cooling the motor 60 in the turbocharger 1 reliably and efficiently. This point will be described. In FIG. 3, the same components as those in FIGS. 1 and 2 are denoted by the same reference numerals, and redundant description is omitted.

  If a sensor for detecting the temperature of the motor 60 in the turbocharger 1 is arranged and based on the output of this sensor, the cooling control can be performed more reliably. In this embodiment, a coil temperature sensor 55 (first temperature detecting means) for directly detecting the temperature of the coil 62 is arranged. The output of the coil temperature sensor 55 is also supplied to the ECU 8. Further, as described above, the exhaust gas temperature sensor 56 for detecting the exhaust gas temperature is disposed on the inlet side of the turbine unit 30 of the turbocharger 1 in order to monitor the state of the engine 2. Based on the exhaust gas temperature detected by the exhaust gas temperature sensor 56, the temperature of the motor 60 can be estimated (predicted). Therefore, the exhaust gas temperature sensor 56 can be used as a second temperature detecting means for indirectly detecting the temperature of the coil 62.

  The ECU 8 refers to the temperature of the motor 60 acquired directly or indirectly as described above, and adjusts the opening of the oil control valve 51 serving as an on-off valve to adjust the flow rate of the lubricating oil flowing through the oil passage 16. adjust. As described above, in the cooling structure of the present embodiment, the oil passage 16 through which lubricating oil for cooling the motor 60 is disposed is disposed, so that the motor 60 can be reliably cooled when necessary. Then, by arranging the oil control valve 51 in the oil passage 16 and opening and closing according to the temperature rise state of the motor 60, the motor 60 can be efficiently cooled when necessary.

  FIG. 4 is a flowchart showing an example of a routine when the ECU 8 cools the motor 60. However, this flowchart illustrates a case where the ECU 8 adjusts the opening degree of the oil control valve 51 with reference to the outputs of both the coil temperature sensor 55 and the exhaust gas temperature sensor 56.

  The ECU 8 activates this routine when, for example, the ignition key of the engine 2 is turned on. The ECU 8 reads the motor temperature from the output of the coil temperature sensor 55 (S101), and further reads the exhaust gas temperature at the turbine inlet from the output of the exhaust gas temperature sensor 56 (S102). Then, the ECU 8 determines whether or not the read temperature is equal to or higher than the allowable temperature TH (S103). The allowable temperature TH here is a predetermined value, and may be stored in a memory area in the ECU 8 so that it can be read out at any time. For example, the predetermined allowable temperature TH1 and the allowable temperature TH2 are set for each of the motor temperature directly detected by the coil temperature sensor 55 and the expected motor temperature indirectly detected by the exhaust gas temperature sensor 56.

  Then, the oil control valve 51 may be set to open when the temperature detected by any one of the sensors exceeds the allowable temperature (S104). Further, for example, an allowable temperature TH3 for the total temperature of the motor temperature and the expected motor temperature may be set, and the oil control valve 51 may be set to open when the total temperature exceeds the allowable temperature.

  As is clear from the above description, when the ECU 8 executes the routine shown in FIG. 4, the temperature of the motor 60 can be confirmed directly or indirectly, and the timing at which cooling is required can be detected and reliably cooled. On the other hand, when the cooling of the motor 60 is not necessary, the ECU 8 executes control not to flow cooling oil (S105). As described above, if lubricating oil enters between the stator 61 and the rotor 65 of the motor 60, the agitation resistance increases and mechanical loss occurs, which is not preferable. Since the structure of the present embodiment can refrain from supplying unnecessary lubricating oil as described above, the stirring resistance of the motor 60 can be reliably suppressed from increasing.

  The flowchart shown in FIG. 4 shows an example of simple opening / closing control in which the oil control valve 51 is opened when the detected motor temperature is equal to or higher than the allowable temperature TH. However, the cooling control of the ECU 8 that controls the driving of the oil control valve 51 is not limited to such a simple one. The flow rate of the lubricating oil for cooling may be adjusted by adjusting the opening degree of the oil control valve 51 in accordance with the detected temperature of the motor 60. In this case, since an optimal amount of lubricating oil can be flowed according to the changing temperature of the motor 60, cooling can be performed more efficiently. FIG. 5 shows an example of an opening map that defines the opening of the oil control valve 51 with respect to the exhaust gas temperature at the turbine inlet. Such an opening map may be stored in a storage area in the ECU 8 in advance. When the temperature of the exhaust gas is high (when the load of the engine 2 is high), it can be easily predicted that the temperature of the motor disposed in the turbocharger 1 will also increase. Therefore, efficient cooling can be performed by adjusting the flow rate of the lubricating oil for cooling based on the exhaust gas temperature at the turbine inlet. Of course, the same opening degree control can be executed by defining an opening degree map that defines the opening degree of the oil control valve 51 with respect to the motor temperature detected by the coil temperature sensor 55.

  In the turbocharger 1 to which the cooling structure for cooling the motor 60 described above is applied, the second lubricating oil passage (oil passage 16) for supplying the lubricating oil for cooling supplies the lubricating oil to the bearing. Since the first lubricating oil passage (oil passage 15) is provided separately, the motor 60 can be reliably cooled. Therefore, for example, even when the engine 2 is stopped, the motor 60 can be cooled if necessary. Further, since the oil pump 16 (lubricating oil supply source) 50 for supplying the lubricating oil to the bearing is simply provided with the oil passage 16 through which the cooling lubricating oil flows, this can be realized easily.

  Then, by providing the oil control valve 51 in the middle of the oil passage 16, the oil control valve 51 can be opened only when necessary to supply the cooling lubricant to the motor 60. Thereby, since unnecessary supply of lubricating oil can be prevented, occurrence of mechanical loss of the motor 60 due to an increase in stirring resistance can be suppressed. Furthermore, by providing the ECU 8 that adjusts the opening degree of the oil control valve 51, a necessary amount of lubricating oil can be supplied in accordance with the temperature rise state of the motor 60 to efficiently perform cooling.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

It is the figure which showed the structure of the turbocharger to which the cooling structure which concerns on an Example is applied. It is the figure which expanded and showed a part of FIG. 1 is a block diagram showing a configuration around an engine to which a turbocharger 1 is applied. FIG. It is the flowchart which showed an example of the routine when ECU cools a motor. It is the figure which showed an example of the opening degree map which prescribes | regulates the opening degree of the oil control valve with respect to the exhaust gas temperature of a turbine inlet.

Explanation of symbols

1 Turbocharger (supercharger)
2 Engine 8 ECU (control means)
15 Oil passage (first lubricating oil passage)
16 Oil passage (second lubricating oil passage)
16DS-R, 16DS-L Discharge port 40, 45 Bearing 60 Motor (electric motor)
61 Stator 62 Coil 65 Rotor 68 Protrusion (Oil intrusion prevention structure)
50 Oil pump 51 Oil control valve (open / close valve)
55 Coil temperature sensor (first temperature detection means)
56 Exhaust gas temperature sensor (second temperature detection means)
LU lubricant

Claims (6)

A supercharger cooling structure equipped with an electric motor,
With a motor, characterized in that a first lubricating oil passage for supplying lubricating oil to the bearing of the supercharger and a second lubricating oil passage for supplying lubricating oil for cooling to the electric motor are provided. Turbocharger cooling structure. The electric motor includes a coil winding portion protruding on both sides;
A discharge port of the second lubricating oil passage is provided so as to cool the coil winding part from both sides,
The supercharger with an electric motor according to claim 1, wherein the electric motor includes an oil intrusion prevention structure that prevents the cooled lubricating oil from entering between the stator and the rotor. Machine cooling structure. The first lubricating oil passage and the second lubricating oil passage are connected to one lubricating oil supply source, and an opening / closing valve is disposed in the second lubricating oil passage. The cooling structure for a supercharger with an electric motor according to claim 1 or 2. The cooling structure for a supercharger with an electric motor according to claim 3, further comprising control means for adjusting the opening of the on-off valve to control the flow rate of the cooling lubricant. A first temperature detecting means for detecting the temperature of the electric motor;
5. The cooling structure for a supercharger with an electric motor according to claim 4, wherein the control means controls the opening degree of the on-off valve based on an output of the first temperature detection means. A second temperature detecting means for detecting the temperature of the exhaust gas supplied to the turbine side of the supercharger;
5. The overload with an electric motor according to claim 4, wherein the control unit estimates the temperature of the electric motor based on an output of the second temperature detection unit and controls an opening degree of the on-off valve. Cooling structure of the feeder.

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