Motor generator cooling device and hybrid engine

Abstract

To provide a motor generator cooling device and a hybrid engine including the motor generator cooling device which can efficiently cool a motor generator while suppressing intrusion of foreign matters into the motor generator.SOLUTION: A motor generator cooling device 10 is disposed between an air cleaner 14 clarifying intake air AR supplied to an engine body 1A and the engine body 1A and includes a casing 12 which covers and accommodates a motor generator 11. The intake air AR flowing into the casing 12 through the air cleaner 14 cools the motor generator 11.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a motor-generator cooling device that cools a motor-generator and a hybrid engine equipped with the motor-generator cooling device. [Background technology]

[0002] Patent Document 1 discloses a motor-generator cooling device that uses an air pump to cool a motor-generator. Here, the air pump supplies air to the motor-generator through a pipe. This air cools the motor-generator. The motor-generator cooling device disclosed in Patent Document 1 has an air pump that corresponds to the amount of heat generated by the motor-generator, which has the advantage of being able to reliably cool the motor-generator, but has the disadvantage of making the device configuration complicated.

[0003] Patent Document 2 discloses a motor-generator cooling device that uses a cooling air passage to cool a motor-generator located between a clutch and a transmission mechanism. The cooling air passage is formed so that it runs from the clutch casing through the interior of the motor-generator to the transmission mechanism. Therefore, airflow generated by the rotation of the motor-generator passes through the cooling air passage. This air cools the motor-generator. The motor-generator cooling device disclosed in Patent Document 2 utilizes the airflow caused by the rotation of the motor-generator itself, which has the advantage of simplifying the device configuration compared to the device using an air pump as in Patent Document 1. However, there is room for improvement in that the cooling capacity cannot be set according to the heat generation of the motor-generator.

[0004] A motor generator typically includes a rotor with a permanent magnet that rotates, a stator with a coil that is fixed to rotatably house the rotor, and a motor case that covers the stator. To prevent the interior of the motor generator from becoming too hot, the motor case has an opening that connects the interior and exterior of the motor generator. This allows heat from the interior of the motor generator to be released to the outside through the opening in the motor case. This can allow foreign matter, such as dust, contained in the outside air to enter the motor generator through the opening in the motor case. In such cases, the motor generator may malfunction due to foreign matter, particularly in hybrid engines installed in industrial machinery used in environments more severe than those used in automobiles. Note that, in this specification, the term "hybrid engine" refers to a prime mover that includes an "electric motor" and an "internal combustion engine." Here, the term "electric motor" includes a "motor generator" that also functions as a generator. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-44406 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-83870 Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a motor-generator cooling device that can efficiently cool the motor-generator while preventing foreign matter from entering the interior of the motor-generator, and a hybrid engine equipped with a motor-generator cooling device. [Means for solving the problem]

[0007] The above problem is solved by a motor-generator cooling device that cools a motor-generator, the motor-generator cooling device comprising a casing that is arranged between the engine and an air cleaner that purifies the intake air supplied to the engine, and that covers and houses the motor-generator, and the intake air that passes through the air cleaner and flows into the casing cools the motor-generator.

[0008] According to the motor-generator cooling device of the present invention, clean intake air, from which dust and other foreign matter has been removed by passing through an air cleaner, passes through the interior of a casing that encases and houses the motor-generator. This allows the motor-generator to be cooled by the intake air while preventing foreign matter from entering the interior of the motor-generator. Furthermore, the motor-generator is cooled by the intake air that flows into the interior of the casing while being enclosed within the casing. Therefore, compared to a case in which the motor-generator is not housed in a casing, for example, the motor-generator is positioned in a position where it is exposed to cooling air blown by an engine cooling fan and is cooled by this cooling air, the motor-generator cooling device of the present invention allows the low-temperature intake air to come into contact with a wide area of ​​the high-temperature outer surface of the motor-generator at a high flow rate, thereby efficiently cooling the motor-generator.

[0009] In the motor-generator cooling device according to the present invention, the casing is preferably fixed to the engine. According to the motor-generator cooling device of the present invention, the casing is fixed to the engine, which makes it possible to suppress vibration of the casing relative to the engine and to suppress noise generation.

[0010] In the motor-generator cooling device according to the present invention, the casing preferably has heat-dissipating fins provided on an outer surface thereof. According to the motor-generator cooling device of the present invention, even if the motor-generator inside the casing generates heat, the motor-generator is cooled by the intake air flowing into the casing. Furthermore, the heat of the motor-generator is dissipated to the outside of the casing via the intake air and through heat-dissipating fins provided on the outer surface of the casing. Therefore, the motor-generator cooling device of the present invention can further prevent the motor-generator from becoming too hot, and can further prevent the motor-generator from being subject to output restrictions due to temperature increases.

[0011] The motor-generator cooling device of the present invention is preferably characterized by further comprising: a first pipe provided between the air cleaner and the casing for guiding the intake air that has passed through the air cleaner into the inside of the casing; and a second pipe provided between the casing and the engine for guiding the intake air that has cooled the motor-generator inside the casing to the intake system of the engine. In the motor-generator cooling device according to the present invention, intake air passes through the air cleaner and flows into the casing through a first pipe provided between the air cleaner and the casing. After cooling the motor-generator inside the casing, the intake air is supplied to the engine's intake system through a second pipe provided between the casing and the engine. Therefore, after cooling the motor-generator inside the casing, the intake air, from which foreign matter has been removed by the air cleaner, is not discharged outside the engine but is instead supplied to the engine's intake system for effective use. Furthermore, the engine's intake negative pressure can be utilized, thereby increasing the flow rate of the intake air cooling the motor-generator inside the casing. This allows for efficient cooling of the motor-generator.

[0012] The motor-generator cooling device according to the present invention is preferably characterized by further comprising a filter provided inside the second pipe for removing foreign matter contained in the intake air that has cooled the motor-generator. According to the motor-generator cooling device of the present invention, a filter is provided inside the second pipe. The filter removes foreign matter contained in the intake air that has cooled the motor-generator. Therefore, even if foreign matter generated by the motor-generator gets mixed into the intake air that has cooled the motor-generator, the filter can remove the foreign matter mixed into the intake air that has cooled the motor-generator from the intake air. Therefore, the motor-generator cooling device of the present invention can supply intake air from which foreign matter has been removed to the intake system of the engine, thereby preventing foreign matter from getting into the intake system of the engine.

[0013] In the motor-generator cooling device according to the present invention, the second pipe preferably has a heat dissipation portion that dissipates heat inside the second pipe to the outside of the second pipe. According to the motor-generator cooling device of the present invention, a heat dissipation section is provided in the second pipe. The heat dissipation section can dissipate heat from the intake air that has been heated by cooling the motor-generator, i.e., heat inside the second pipe, to the outside of the second pipe. Therefore, the motor-generator cooling device of the present invention can supply intake air to the intake system of the engine at a lower temperature than the temperature immediately after passing through the motor-generator.

[0014] The motor-generator cooling device of the present invention is preferably characterized by further comprising a third pipe connected to the first pipe and the second pipe, for directing a portion of the intake air that has flowed through the first pipe to the second pipe without passing through the casing. In the motor-generator cooling device according to the present invention, because the casing houses the motor-generator, the pressure loss that occurs when the intake air passes through the third pipe is smaller than the pressure loss that occurs when the intake air passes through the casing. Therefore, when the third pipe is provided, the negative pressure of the intake air supplied to the engine's intake system is smaller than when the third pipe is not provided. Therefore, the third pipe can reduce the intake negative pressure of the engine, thereby improving the fuel efficiency of the engine.

[0015] In the motor-generator cooling device according to the present invention, preferably, the casing has a first hole through which the output shaft of the motor-generator passes and protrudes to the outside of the casing. The motor-generator cooling device according to the present invention is characterized in that it further includes a first seal member provided in the first hole to maintain airtightness between the casing and the output shaft. In the motor-generator cooling device according to the present invention, a first seal member is provided in a first hole portion of the casing. The first hole allows the output shaft of the motor-generator to pass through and protrude to the outside of the casing. The first seal member also maintains airtightness between the casing and the output shaft of the motor-generator. This makes it possible for the motor-generator cooling device according to the present invention to prevent foreign matter from outside the casing from entering the inside of the casing through a gap between the casing and the output shaft of the motor-generator.

[0016] In the motor-generator cooling device according to the present invention, preferably, the casing has a second hole through which a wire harness of the motor generator passes and leads to the outside of the casing. The motor-generator cooling device according to the present invention is characterized in that it further includes a second seal member provided in the second hole for maintaining airtightness between the casing and the wire harness. According to the motor-generator cooling device of the present invention, a second seal member is provided in the second hole portion of the casing. The second hole portion allows the motor-generator wire harness to pass through and lead to the outside of the casing. The second seal member also maintains airtightness between the casing and the motor-generator wire harness. This makes it possible for the motor-generator cooling device of the present invention to prevent foreign matter from outside the casing from entering the inside of the casing through a gap between the casing and the motor-generator wire harness.

[0017] In the motor-generator cooling device of the present invention, it is preferable that the air cleaner is a second air cleaner provided in an intake path separate from the intake path of a first air cleaner provided in the engine, and the intake air that has passed through the second air cleaner cools the motor-generator, then merges with the intake air that has passed through the first air cleaner and is supplied to the engine. According to the motor-generator cooling device of the present invention, the second air cleaner intake path, which is subject to pressure loss associated with cooling the motor-generator inside the casing, is provided as a dedicated intake path for intake air, separate from the first air cleaner intake path provided in the engine. After cooling the motor-generator, the intake air passing through the second air cleaner intake path merges with the intake air passing through the first air cleaner intake path. The merged intake air is supplied to the engine's intake system. Because the first air cleaner intake path has a pressure loss smaller than the pressure loss of the second air cleaner intake path, the negative pressure of the intake air supplied to the engine's intake system is smaller than when only the second air cleaner intake path is provided. Therefore, the engine's intake negative pressure can be reduced compared to when only the second air cleaner intake path is provided, thereby improving engine fuel efficiency.

[0018] The above problem is also solved by a hybrid engine equipped with a motor-generator cooling device that cools a motor-generator, wherein the motor-generator cooling device is arranged between the engine and an air cleaner that purifies the intake air supplied to the engine, and has a casing that covers and houses the motor-generator, and the intake air that passes through the air cleaner and flows into the casing cools the motor-generator.

[0019] In a hybrid engine equipped with a motor-generator cooling device according to the present invention, clean intake air, which has passed through an air cleaner to remove dust and other foreign matter, passes through the interior of a casing that encases and houses the motor-generator. This allows the motor-generator to be cooled by the intake air while preventing foreign matter from entering the interior of the motor-generator. Furthermore, the motor-generator is cooled by the intake air that flows into the casing while being enclosed within the casing. Therefore, compared to a case in which the motor-generator is not housed in a casing, for example, the motor-generator is positioned in a position where it is exposed to cooling air from the engine's cooling fan and is cooled by this cooling air, the motor-generator cooling device allows low-temperature intake air to flow at a high flow rate into contact with a wide area of ​​the high-temperature outer surface of the motor-generator, thereby efficiently cooling the motor-generator. This prevents the motor-generator from becoming too hot, thereby preventing output restrictions due to temperature increases from being imposed on the motor-generator and preventing a decrease in the motor-generator's ability to drive the hybrid engine. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a motor-generator cooling device that can efficiently cool a motor-generator while preventing foreign matter from entering the interior of the motor-generator, and a hybrid engine equipped with a motor-generator cooling device. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view showing a hybrid engine equipped with a motor-generator cooling device according to an embodiment of the present invention; [Figure 2] 1 is a side view showing a state in which a part of the motor-generator cooling device according to the present embodiment is cut away; [Figure 3] 1 is a front view showing a state in which a part of the motor-generator cooling device according to the present embodiment is cut away; [Figure 4] 1 is a plan view showing a motor-generator cooling device according to an embodiment of the present invention; [Figure 5] 1 is a block diagram schematically illustrating a hybrid engine according to an embodiment of the present invention. [Figure 6] 1 is a perspective view schematically showing a hybrid engine according to an embodiment of the present invention; [Figure 7] FIG. 4 is a block diagram schematically showing a hybrid engine according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] Preferred embodiments of the present invention will now be described in detail with reference to the drawings. The embodiments described below are preferred examples of the present invention, and therefore various technically preferable limitations are applied thereto, but the scope of the present invention is not limited to these aspects unless otherwise specified in the following description to the effect that the present invention is particularly limited. Furthermore, in each drawing, similar components are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0023] (First embodiment) (Example of hybrid engine 1 structure) FIG. 1 is a perspective view showing a hybrid engine equipped with a motor-generator cooling device according to a first embodiment of the present invention. FIG. 2 is a side view showing a state in which a part of the motor-generator cooling device according to this embodiment is cut away. FIG. 3 is a front view showing the motor-generator cooling device according to this embodiment with a portion cut away. FIG. 4 is a plan view showing the motor-generator cooling device according to this embodiment.

[0024] The hybrid engine 1 shown in FIGS. 1 to 4 is a hybrid engine mounted on an industrial machine, and includes an engine body 1A, a motor generator 11, and a motor generator cooling device 10. Examples of industrial machines include construction machines such as forklifts and tractors, and agricultural machines. The engine body 1A may be a multi-cylinder diesel engine such as a high-output turbocharged supercharged three-cylinder or four-cylinder engine. The industrial machine is not limited to a vehicle, and may be a fixed object such as a generator. The engine body 1A may also be a naturally aspirated diesel engine, a turbocharged supercharged gasoline engine, a naturally aspirated gasoline engine, or the like.

[0025] The hybrid engine 1 according to this embodiment is, for example, a parallel type. In the parallel type hybrid engine 1, when power is needed, such as when starting or accelerating, the driving force of the motor generator 11 shown in FIG. 2 assists the driving force of the engine body 1A via the transmission belt 34. That is, the motor generator 11 operates using voltage supplied from the hybrid battery and assists the engine body 1A when needed. For this reason, the motor generator 11 is larger and has higher output than a normal alternator.

[0026] As shown in Fig. 1, the engine body 1A has a cylinder block 2, a cylinder head 3, a head cover 4, an oil pan 5, an exhaust gas aftertreatment device 6, a turbocharger 7, and a cooling fan 9. The cylinder head 3 is mounted on the cylinder block 2. The head cover 4 is mounted on the cylinder head 3. The cylinder head 3 is equipped with the exhaust gas aftertreatment device 6 and the turbocharger 7.

[0027] (Motor generator cooling device 10) Next, the motor-generator cooling device 10 according to this embodiment will be described. 1 and 2, the motor-generator cooling device 10 is fixed to the engine body 1A on the side of the front part of the engine body 1A, i.e., at a position close to the cooling fan 9. The motor-generator cooling device 10 has a casing 12, and cools the motor-generator 11 with the motor-generator 11 enclosed within the casing 12.

[0028] <Casing 12> FIG. 5 is a block diagram that schematically shows the hybrid engine according to this embodiment. FIG. 6 is a perspective view that schematically shows the hybrid engine according to this embodiment. 5 and 6, the motor-generator cooling device 10 has a casing 12. The casing 12 is made of a metal with excellent thermal conductivity, such as iron or aluminum, and covers and houses the motor-generator 11. As a result, the casing 12 prevents foreign matter such as dust, oil, and moisture from adhering to the motor-generator 11, thereby reducing the failure rate of the motor-generator 11.

[0029] The casing 12 is disposed between the air cleaner 14 and the intake system of the engine body 1A. For example, the casing 12 is attached to a plurality of locations on the side of the front part of the cylinder head 3 using bolts 15. This allows the casing 12 to be securely fixed to the engine body 1A, thereby suppressing vibration of the casing 12 relative to the engine body 1A and suppressing noise generated from the casing 12 when the hybrid engine 1 is operating.

[0030] As shown by the arrows in FIGS. 5 and 6, outside air flows into the engine compartment 13 as intake air AR. The outer shape of the casing 12 is made to be approximately cylindrical, taking into consideration the air resistance of the intake air AR. The tip end 12T of the casing 12 has a streamlined portion 12S with rounded corners. This allows the intake air AR to flow smoothly around the casing 12, even if the casing 12 is mounted on the side of the front part of the engine main body 1A. For this reason, the casing 12 of this embodiment teeth, Compared to a square casing, for example, a rectangular parallelepiped casing, the casing 12 can reduce air resistance and noise associated with the air resistance. In this way, the casing 12 is formed in a streamlined shape so as not to obstruct the flow of intake air AR inside the engine compartment 13.

[0031] <First pipe 20 and second pipe 21> 5, 6, and 1, the casing 12 is connected to a first pipe 20 that takes in intake air AR into the casing 12 and a second pipe 21 that discharges the intake air AR from the inside of the casing 12 to the outside. The first pipe 20 and the second pipe 21 are cylindrical pipes made of a metal with excellent heat dissipation properties, such as iron or aluminum. However, the material of the first pipe 20 and the second pipe 21 is not limited to metal, and they may be made of a resin such as rubber that has elasticity and flexibility.

[0032] One end 20A of the first pipe 20 is connected to the air cleaner 14. The other end 20B of the first pipe 20 is connected to the casing 12 and communicates with the internal space SP of the casing 12. In this way, the first pipe 20 is provided between the air cleaner 14 and the casing 12, and can guide the intake air AR that has passed through the air cleaner 14 into the internal space SP of the casing 12 (see FIG. 3).

[0033] 3 and 4, one end 21A of the second pipe 21 is connected to the internal space SP of the casing 12. The other end 21B of the second pipe 21 is connected to the inlet of the blow-by gas mixing joint 22. In this way, the second pipe 21 is provided between the casing 12 and the engine body 1A, and can guide the intake air AR discharged from the internal space SP of the casing 12 to the intake system of the engine body 1A.

[0034] 1 and 2, the middle section 21C of the second piping 21 is arranged in a detour so as not to come into contact with the engine body 1A. As shown in Fig. 1 and 3, the middle section 21C occupies a relatively long portion of the entire length of the second piping 21 and is arranged along the Y direction so as to cross the front side of the engine body 1A. As a result, the second piping 21 is forcibly cooled by cooling air sent from the cooling fan 9 inside the engine compartment 13.

[0035] 5 and 6, low-temperature intake air AR enters air cleaner 14 inside engine compartment 13, and after foreign matter such as dust has been removed and purified, passes through first piping 20 and flows into internal space SP of casing 12 as a cooling medium for motor generator 11. After cooling motor generator 11, the low-temperature intake air AR that has flowed into the inside of casing 12 is discharged from internal space SP of casing 12 through second piping 21 to blow-by gas mixing joint 22, which serves as the intake system of engine body 1A.

[0036] As shown in FIG. 5, a filter 23 different from the air cleaner 14 may be provided inside the second pipe 21. In this case, even if foreign matter such as dust is present in the intake air AR that has passed through the internal space SP of the casing 12, the filter 23 can remove the foreign matter from the intake air AR. As a result, even if foreign matter generated by the motor-generator 11 is mixed into the intake air AR that has cooled the motor-generator 11, the filter 23 can remove the foreign matter mixed into the intake air AR that has cooled the motor-generator 11 from the intake air AR. Therefore, the motor-generator cooling device 10 according to this embodiment can supply the intake air AR from which foreign matter has been removed to the intake system of the engine body 1A, thereby preventing foreign matter from being mixed into the intake system of the engine body 1A. Furthermore, malfunctions of the engine body 1A can be prevented.

[0037] As shown in Figure 6, the blow-by gas mixing joint 22 mixes intake air AR of the intake system with gas components G of the flow-by gas to create new intake air AS, which is supplied to the blower 25 of the turbocharger 7. Meanwhile, exhaust gas that has passed through the exhaust passage of the engine body 1A is supplied to the turbine 26 of the turbocharger 7, causing the turbine 26 and the blower 25 to rotate at high speed. As a result, the intake air AS is compressed by the blower 25 and supercharged into the intake passage of the intake system of the engine body 1A. In this way, the intake air AR that has passed through the inside of the casing 12 to cool the motor-generator 11 is mixed with the gas components G of the flow-by gas and used as intake air AS.

[0038] <Heat dissipation fins 30 and heat dissipation portion 33> As shown in FIG. 4 , the casing 12 has a plurality of heat dissipation fins 30. The plurality of heat dissipation fins 30 are provided on the outer surface of the casing 12 at intervals. The heat dissipation fins 30 can dissipate heat generated by the operation of the motor-generator 11 from the internal space SP of the casing 12 to the outside of the casing 12. At this time, the fins 30 come into contact with the cool air sent from the cooling fan 9, so that the heat generated by the operation of the motor-generator 11 can be efficiently dissipated to the outside of the casing 12. As a result, the fins 30 can prevent the motor-generator 11 housed in the casing 12 from becoming too hot during operation and can prevent output restrictions on the motor-generator 11 due to temperature increases. Furthermore, the heat dissipation fins 30 are preferably formed along the flow direction X of the intake air AR passing through the engine compartment 13, thereby suppressing the generation of wind noise.

[0039] As shown in FIG. 4 , the second pipe 21 has a heat dissipation section 33. The heat dissipation section 33 may be formed in a portion of the second pipe 21, for example, in the middle section 21C of the second pipe 21, or may be formed over the entire length of the second pipe 21. The heat dissipation section 33 has, for example, a bellows shape to increase the heat dissipation area, and dissipates heat inside the second pipe 21 to the outside of the second pipe 21. That is, when the intake air AR that has cooled the motor generator 11 passes through the second pipe 21, the heat dissipation section 33 dissipates the heat of the intake air AR that has been warmed by cooling the motor generator 11 to the outside of the second pipe 21. At this time, the heat dissipation section 33 comes into contact with the cool air sent from the cooling fan 9, and therefore the heat of the intake air AR that has been warmed by cooling the motor generator 11 can be efficiently dissipated to the outside of the second pipe 21. Therefore, the motor-generator cooling device 10 according to this embodiment can supply the intake air AR to the intake system of the engine body 1A at a temperature lower than the temperature of the intake air immediately after passing through the motor-generator 11. Therefore, the cooled intake air AR is supplied to the turbocharger 7 from the second pipe 21 via the blow-by gas mixing joint 22. This can increase the efficiency of the engine body 1A.

[0040] As shown in Fig. 5, the operation of the engine main body 1A is controlled by an engine ECU (Electronic Control Unit) 50. The motor generator 11 is operated by a voltage supplied from a hybrid battery 51. The drive voltage of the hybrid battery 51 is boosted by a boost converter 52 from, for example, 12 V to 48 V and supplied to the motor generator 11 via a wire harness 39. The operations of the hybrid battery 51 and the boost converter 52 are controlled by a hybrid ECU 53. Examples of the hybrid battery 51 include a lithium-ion battery, a nickel-metal hydride battery, and an all-solid-state battery.

[0041] As shown in FIG. 5, a pulley 11P is attached to the output shaft 11G of the motor generator 11. A pulley 1P is attached to the output shaft 1S of the engine body 1A. A transmission belt 34 is wound around the pulleys 1P and 11P. As a result, the driving force of the motor generator 11 is transmitted to the output shaft 1S of the engine body 1A via the transmission belt 34 as needed, for example, during starting, acceleration, or running, to assist the driving force of the output shaft 1S of the engine body 1A. The output shaft 1S of the engine body 1A transmits power to wheels 36 via a power transmission mechanism 35. In addition, a working device 37 is operated using the power of the output shaft 1S to perform a predetermined task. An example of the predetermined task of the working device 37 is plowing using a tractor.

[0042] The motor generator 11 is of a so-called belt-driven starter generator type (BSG) in which the driving force of the output shaft 11G of the motor generator 11 assists the output shaft 1S of the engine body 1A via a transmission belt 34. However, the type of the motor generator 11 is not limited to this, and may be of a so-called integrated starter generator type (ISG), in which the output shaft 11G of the motor generator 11 is coaxial with the output shaft 1S of the engine body 1A.

[0043] <First seal member 40 and second seal member 41> 5, the casing 12 has a first hole 12H for passing the output shaft 11G. The output shaft 11G protrudes to the outside of the casing 12 through the first hole 12H. A first seal member 40 that maintains airtightness between the casing 12 and the output shaft 11G is provided in the first hole 12H. The first seal member 40 can prevent foreign matter from outside the casing 12 from entering the internal space SP of the casing 12 through a gap between the casing 12 and the output shaft 11G.

[0044] 5, the casing 12 has a second hole 12R for passing a wire harness 39 therethrough. The wire harness 39 is led to the outside of the casing 12 through the second hole 12R. A second seal member 41 is provided in the second hole 12R to maintain airtightness between the casing 12 and the wire harness 39. The second seal member 41 can prevent foreign matter from outside the casing 12 from entering the internal space SP of the casing 12 through a gap between the casing 12 and the wire harness 39.

[0045] The casing 12 also serves as part of an intake piping system that draws in and passes intake air AR. The first seal member 40 fills the first hole 12H of the casing 12, and the second seal member 41 fills the second hole 12R of the casing 12, thereby maintaining the internal space SP of the casing 12 airtight. Therefore, the first seal member 40 and the second seal member 41 prevent foreign matter from entering the motor-generator 11 housed in the internal space SP of the casing 12, thereby reducing the failure rate of the motor-generator 11.

[0046] The motor-generator cooling device 10 according to this embodiment may further include a third pipe 24 indicated by a two-dot chain line in FIGS. 2 and 6. One end of the third pipe 24 is connected to the other end 20B of the first pipe 20. The other end of the third pipe 24 is connected to one end 21A of the second pipe 21. That is, the third pipe is connected to the first pipe 20, which is located upstream of the casing 12 in the flow of the intake air AR, and the second pipe 21, which is located downstream of the casing 12 in the flow of the intake air AR. The third pipe 24 functions as a bypass pipe and guides a portion of the intake air AR that has flowed through the first pipe 20 to the second pipe 21 without passing through the casing 12, as indicated by the arrows in FIG. 6. The other portion of the intake air AR flows into the internal space SP of the casing 12, as described above. The intake air AR that passes through the third pipe 24 merges with the intake air AR that has cooled the motor generator 11 in the internal space SP of the casing 12 at the connection between the second pipe 21 and the third pipe 24, and is supplied to the intake system of the engine main body 1A.

[0047] According to this, because the casing 12 accommodates the motor-generator 11 in the internal space SP, the pressure loss that occurs when the intake air AR passes through the third pipe 24 is smaller than the pressure loss that occurs when the intake air AR passes through the casing 12. Therefore, when the third pipe 24 is provided, the negative pressure of the intake air AR supplied to the intake system of the engine body 1A is smaller than when the third pipe 24 is not provided. Therefore, the third pipe 24 can reduce the intake negative pressure of the engine body 1A, thereby improving the fuel efficiency of the engine body 1A.

[0048] As described above, with the motor-generator cooling device 10 according to this embodiment, clean intake air AR, which has passed through the air cleaner 14 and from which foreign matter such as dust has been removed, passes through the interior of the casing 12 that encases and houses the motor-generator 11. This allows the motor-generator 11 to be cooled by the intake air AR while preventing foreign matter from entering the interior of the motor-generator 11. Furthermore, the motor-generator 11 is cooled by the intake air AR that flows into the interior of the casing 12 while being enclosed within the casing 12. Therefore, the motor-generator cooling device 10 according to this embodiment can bring low-temperature intake air into contact with a wide area of ​​the high-temperature outer surface of the motor-generator at a high flow rate, thereby efficiently cooling the motor-generator 11, compared to a case in which the motor-generator 11 is not housed in the casing 12, for example, a case in which the motor-generator 11 is positioned in a position where it is exposed to cooling air blown by an engine cooling fan and is cooled by this cooling air. This prevents the motor-generator 11 from becoming too hot, thereby preventing output restrictions on the motor-generator 11 due to temperature increases and preventing a decrease in the motor-generator 11's ability to drive the hybrid engine 1.

[0049] Furthermore, the casing 12 is fixed to the engine body 1A, which prevents the casing 12 from vibrating relative to the engine body 1A, thereby suppressing noise generation.

[0050] Furthermore, the intake air AR that has passed through the air cleaner 14 flows into the inside of the casing 12 through a first pipe 20 provided between the air cleaner 14 and the casing 12. The intake air AR that has cooled the motor-generator 11 inside the casing 12 is supplied to the intake system of the engine body 1A through a second pipe 21 provided between the casing 12 and the engine body 1A. Therefore, after cooling the motor-generator 11 inside the casing 12, the intake air AR from which foreign matter has been removed by the air cleaner 14 is not discharged to the outside of the engine body 1A but is instead supplied to the intake system of the engine body 1A and used effectively. Furthermore, because the intake negative pressure of the engine body 1A can be utilized, the flow rate of the intake air AR that cools the motor-generator 11 inside the casing 12 can be increased. This allows the motor-generator 11 to be cooled efficiently.

[0051] (Second embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. In addition, in cases where the components of the motor-generator cooling device 10A of the second embodiment are similar to the components of the motor-generator cooling device 10 of the first embodiment described above with reference to Figures 1 to 6, duplicate explanations will be omitted as appropriate, and the following explanation will focus on the differences.

[0052] FIG. 7 is a block diagram that schematically shows a hybrid engine according to a second embodiment of the present invention. In the first embodiment described above, one air cleaner is provided. That is, the air cleaner 14 shown in FIG. 5 is provided in the engine body 1A to supply fresh intake air AR to the engine body 1A. In the first embodiment, the entire amount of intake air AR supplied from the air cleaner 14 is introduced into the internal space SP of the casing 12, which serves as part of the intake system, to cool the motor-generator 11, and is then supplied to the intake system of the engine body 1A as intake air AS. Note that, as described above with reference to FIGS. 2 and 6, when the third piping 24 is provided, a portion of the intake air AR supplied from the air cleaner 14 passes through the third piping 24 and is guided to the second piping 21 without passing through the casing 12. In addition, another portion of the intake air AR supplied from the air cleaner 14 is guided into the internal space SP of the casing 12 to cool the motor-generator 11, and is then guided to the second piping 21.

[0053] In contrast, a motor-generator cooling device 10A of a second embodiment shown in FIG. 7 is provided with two air cleaners: a first air cleaner 14T and a second air cleaner 70. The first air cleaner 14T corresponds to the air cleaner 14 of the first embodiment. The second air cleaner 70 is provided in addition to the first air cleaner 14T provided in the engine body 1A. In other words, the second air cleaner 70 is provided in an intake path separate from the intake path of the first air cleaner 14T. The second air cleaner 70 is a smaller device than the first air cleaner 14T. The intake air AT purified by the first air cleaner 14T is supplied to the blow-by gas mixing joint 22 via the main pipe 60.

[0054] One end 20A of the first piping 20 is connected to the second air cleaner 70. The other end 20B of the first piping 20 is connected to the casing 12 and communicates with the internal space SP of the casing 12. In this way, the first piping 20 is provided between the second air cleaner 70 and the casing 12, and can guide the intake air AR that has passed through the second air cleaner 70 into the internal space SP of the casing 12 (see FIG. 3).

[0055] On the other hand, one end 21A of the second pipe 21 is connected to the internal space SP of the casing 12. The other end 21B of the second pipe 21 is connected to the middle of the main pipe 60. In this way, the second pipe 21 is provided between the casing 12 and the main pipe 60 of the engine body 1A, and can guide the intake air AR discharged from the internal space SP of the casing 12 to the intake system of the engine body 1A.

[0056] Specifically, the low-temperature clean intake air AT that has passed through the first air cleaner 14T merges with the clean intake air AR that has passed through the second pipe 21 in the main pipe 60, and is supplied to the blow-by gas mixing joint 22 and the turbocharger 7. In other words, the intake air AR that has passed through the second air cleaner 70 cools the motor generator 11, and then merges with the intake air AT that has passed through the first air cleaner 14T, and is supplied to the engine body 1A.

[0057] In the motor-generator cooling device 10A according to this embodiment, the intake path of the second air cleaner 70, which is subject to pressure loss associated with cooling the motor-generator 11 inside the casing 12, is provided as a dedicated intake path for intake air, separate from the intake path of the first air cleaner 14T provided in the engine body 1A. After cooling the motor-generator 11, the intake air AR passing through the intake path of the second air cleaner 70 merges with the intake air AT passing through the intake path of the first air cleaner 14T. The merged intake air is further merged with gas component G of the flow-by gas at the blow-by gas mixing joint 22 and supplied as intake air AS to the intake system of the engine body 1A. Because the intake path of the first air cleaner 14T has a pressure loss smaller than the pressure loss of the intake path of the second air cleaner 70, the negative pressure of the intake air supplied to the intake system of the engine body 1A is smaller than when only the intake path of the second air cleaner 70 is present. Therefore, compared to the case where only the intake path of the second air cleaner 70 exists, the intake negative pressure of the engine body 1A can be made smaller, and accordingly, the fuel efficiency of the engine body 1A can be improved.

[0058] Also, the same effects as those described above for the motor-generator cooling device 10 according to the first embodiment can be obtained. Furthermore, the motor-generator cooling device 10A according to this embodiment may have the third piping 24 described above with reference to Figures 2 and 6. As a result, as described above with reference to the first embodiment, the third piping 24 can reduce the intake negative pressure of the engine body 1A, thereby improving the fuel efficiency of the engine body 1A.

[0059] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the claims. The configurations of the above embodiments can be partially omitted or arbitrarily combined in a different manner from the above. [Explanation of symbols]

[0060] 1: Engine, 1A: Engine body, 1P: Pulley, 1S: Output shaft, 2: Cylinder block, 3: Cylinder head, 4: Head cover, 5: Oil pan, 6: Exhaust gas aftertreatment device, 7: Turbocharger, 8: Radiator, 9: Cooling fan, 10: Motor generator cooling device, 10A: Motor generator cooling device, 11: Motor generator, 11G: Output shaft, 11P: Pulley, 12: Casing, 12H: First hole portion, 12R: Second hole portion, 12S: Streamlined portion, 12T: Tip portion, 13: Engine compartment, 14: Air cleaner, 14T: First air cleaner, 15: Bolt, 20: First piping, 20A: One end portion, 20B: Other end portion, 21: Second piping, 21A: One end portion, 21B: Other end portion, 21C: Intermediate section, 22: Blow-by gas mixing joint, 23: Filter, 24: Third pipe, 25: Blower, 26: Turbine, 30: Fin, 33: Heat dissipation section, 34: Transmission belt, 35: Power transmission mechanism, 36: Wheel, 37: Work device, 39: Harness, 40: First seal member, 41: Second seal member, 50: Engine ECU, 51: Hybrid battery, 52: Boost converter, 53: Hybrid ECU, 60: Main pipe, 70: Second air cleaner, AR: Intake air, AS: Intake air, AT: Intake air, G: Gas component, SP: Internal space

Claims

1. A motor-generator cooling device that cools a motor-generator, a casing that covers and houses the motor generator; The casing is disposed between the engine and an air cleaner that purifies intake air supplied to the engine, a first pipe that guides the intake air that has passed through the air cleaner into the inside of the casing; a second pipe provided between the casing and the engine, for guiding the intake air discharged from inside the casing to an intake system of the engine; Furthermore, The first pipe is provided between the air cleaner and the casing, One end of the first pipe is connected to the air cleaner, the other end of the first pipe is connected to the casing and communicates with the inside of the casing, the intake air that passes through the air cleaner and flows into the inside of the casing via the first piping cools the motor generator, and the intake air that has cooled the motor generator inside the casing is led to an intake system of the engine via the second piping, The tip of the casing has a streamlined portion, A motor-generator cooling device characterized in that an intermediate portion of the second pipe is arranged to bypass the engine so as not to come into contact with the engine, and is arranged to cross the front side of the engine.

2. 2. The motor-generator cooling device according to claim 1, wherein the casing is fixed to the engine.

3. 3. The motor-generator cooling device according to claim 1, wherein the casing has heat-dissipating fins provided on an outer surface thereof.

4. 2. The motor-generator cooling device according to claim 1, further comprising a filter provided inside the second pipe for removing foreign matter contained in the intake air that has cooled the motor-generator.

5. 5. The motor-generator cooling device according to claim 1, wherein the second pipe has a heat dissipation portion that dissipates heat inside the second pipe to the outside of the second pipe.

6. a third pipe connected to the first pipe and the second pipe, for guiding a portion of the intake air that has flowed through the first pipe to the second pipe without passing through the casing; The motor-generator cooling device according to any one of claims 1 to 5, characterized in that the intake air that passes through the third pipe merges with the intake air that has cooled the motor-generator inside the casing at the connection between the second pipe and the third pipe, and is led to the intake system of the engine.

7. the casing has a first hole portion through which the output shaft of the motor generator passes and which projects to the outside of the casing; The motor-generator cooling device according to any one of claims 1 to 6, further comprising a first seal member provided in the first hole portion to maintain airtightness between the casing and the output shaft.

8. the casing has a second hole portion through which a wire harness of the motor generator passes and is led to the outside of the casing, The motor-generator cooling device according to any one of claims 1 to 7, further comprising a second seal member provided in the second hole portion to maintain airtightness between the casing and the wire harness.

9. the air cleaner is a second air cleaner provided in an intake path separate from an intake path of a first air cleaner provided in the engine, a pressure loss in the intake path of the first air cleaner is smaller than a pressure loss in the intake path of the second air cleaner; 9. The motor-generator cooling device according to claim 1, wherein the intake air that has passed through the second air cleaner cools the motor-generator, and then merges with the intake air that has passed through the first air cleaner and is supplied to the engine.

10. A hybrid engine equipped with a motor-generator cooling device that cools a motor-generator, The motor generator cooling device includes: a casing that covers and houses the motor generator; The casing is disposed between the engine and an air cleaner that purifies intake air supplied to the engine, a first pipe that guides the intake air that has passed through the air cleaner into the inside of the casing; a second pipe provided between the casing and the engine, for guiding the intake air discharged from inside the casing to an intake system of the engine; and The first pipe is provided between the air cleaner and the casing, One end of the first pipe is connected to the air cleaner, the other end of the first pipe is connected to the casing and communicates with the inside of the casing, the intake air that passes through the air cleaner and flows into the inside of the casing via the first piping cools the motor generator, and the intake air that has cooled the motor generator inside the casing is led to an intake system of the engine via the second piping, The tip of the casing has a streamlined portion, A hybrid engine, characterized in that an intermediate portion of the second pipe is arranged to bypass the engine so as not to come into contact with the engine, and is arranged to cross a front side of the engine.

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