JP2013207957A - Motor cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cool down an electric motor while suppressing energy required for cooling.SOLUTION: A supplying oil path 19 and a discharging oil path 20 are connected to a housing 18 housing a motor generator M2. An electric oil pump 22 is connected to the supplying oil path 19, and a supply flow rate of cooling oil X is adjusted by the electric oil pump 22. In addition, a variable throttle valve 27 is provided to the discharging oil path 20, and a discharge flow rate of the cooling oil X is adjusted by the variable throttle valve 27. In the case that a predicted calorific value of the motor generator M2 is small, the supply flow rate and the discharge flow rate are controlled to a decrement side to reduce a circulation flow rate of the cooling oil X while keeping an oil surface height. On the other hand, in the case that the predicted calorific value of the motor generator M2 is large, the supply flow rate and the discharge flow rate are controlled to an increment side to increase the circulation flow rate of the cooling oil X while keeping the oil surface height. Thereby, the motor generator M2 is appropriately cooled down while suppressing energy.

Description

  The present invention relates to a motor cooling device that cools an electric motor mounted on a vehicle.

  Hybrid vehicles including an engine and an electric motor as drive sources, and electric vehicles including only an electric motor as a drive source have been developed. In order for these electric motors to function normally, it is important to prevent permanent magnets from demagnetizing and insulating coating deterioration by actively cooling the electric motors that generate heat when energized. Therefore, in order to cool the electric motor, a cooling device has been proposed in which the cooling oil scraped up by the gear is stored in a catch tank above the motor and the cooling oil is dropped from the catch tank to the electric motor (for example, , See Patent Document 1). Since the cooling device described in Patent Document 1 can supply cooling oil to an electric motor without using an oil pump, it is possible to reduce energy required for cooling.

JP 2011-250524 A

  By the way, in recent hybrid vehicles and electric vehicles, since the amount of heat generation has increased with the increase in the output of the electric motor, it is necessary to actively supply cooling oil using an oil pump. Yes. However, continuing to supply a large amount of cooling oil by the oil pump increases the energy required for cooling and causes a reduction in fuel consumption performance and power consumption performance of the vehicle. For this reason, it is desired to suppress energy required for cooling by appropriately controlling the oil pump in accordance with the operating state of the electric motor.

  An object of the present invention is to cool an electric motor while suppressing energy required for cooling.

  The motor cooling device of the present invention is a motor cooling device that cools an electric motor mounted on a vehicle, and is provided in a housing in which the electric motor is accommodated and a supply path that supplies cooling oil to the housing. Based on a supply-side adjustment mechanism that adjusts the supply flow rate of oil, a discharge-side adjustment mechanism that adjusts the discharge flow rate of cooling oil provided in a discharge path that discharges cooling oil from the housing, and a control target value of the electric motor A heat generation amount calculation unit that calculates a predicted heat generation amount of the electric motor, and a flow rate control unit that controls the supply side adjustment mechanism and the discharge side adjustment mechanism based on the predicted heat generation amount, The control unit increases or decreases the supply flow rate and the discharge flow rate based on the predicted calorific value, thereby cooling the oil level of the cooling oil in which the electric motor is immersed in a predetermined range. Wherein the increase or decrease of the circulation flow rate.

  In the motor cooling device of the present invention, when the predicted heat generation amount increases, the flow rate control unit increases the supply flow rate and the discharge flow rate to increase the circulation flow rate, while the predicted heat generation amount decreases. In this case, the circulation flow rate is decreased by decreasing the supply flow rate and the discharge flow rate. Further, in the motor cooling device of the present invention, the cooling oil supplied into the housing from the supply path is supplied to the coil end portion of the stator coil of the electric motor and travels downward along the outer periphery of the coil end portion. It is characterized by flowing. In the motor cooling device of the present invention, the flow rate controller increases the circulation flow rate by increasing the supply flow rate and the discharge flow rate when the temperature difference between the cooling oil and the electric motor decreases. On the other hand, when the temperature difference increases, the circulating flow rate is decreased by decreasing the supply flow rate and the discharge flow rate. Further, in the motor cooling device of the present invention, the flow rate control unit performs at least one of the supply flow rate decrease control and the discharge flow rate increase control when the electric motor tilts beyond a predetermined value. Performing cooling oil in the housing.

  According to the present invention, the supply flow rate of the cooling oil supplied to the housing and the discharge flow rate of the cooling oil discharged from the housing are controlled based on the predicted heat generation amount of the electric motor accommodated in the housing. Thereby, since the circulating flow rate of the cooling oil can be increased or decreased according to the predicted heat generation amount, it is possible to appropriately cool the electric motor while suppressing energy required for cooling. In addition, since the electric motor can be kept immersed in the cooling oil by keeping the oil level of the cooling oil immersed in the electric motor within a predetermined range, the circulating flow rate of the cooling oil is reduced while maintaining the cooling capacity. It becomes possible.

It is the schematic which shows the structure of the motor cooling device which is one embodiment of this invention. It is a flowchart which shows the control procedure of the electric oil pump and variable throttle valve by a control unit. (a) And (b) is explanatory drawing which shows an example of the torque map referred when setting target torque. It is explanatory drawing which shows an example of the efficiency map referred when calculating the predicted calorific value. It is explanatory drawing which shows an example of the flow map referred when setting a supply flow rate. It is explanatory drawing which shows an example of the opening degree map referred when setting a flow-path area. (a) And (b) is explanatory drawing which shows the supply condition of the cooling oil with respect to a housing. It is a flowchart which shows the other control procedure of the electric oil pump and variable throttle valve by a control unit. (a) And (b) is explanatory drawing which shows the supply condition of the cooling oil with respect to a housing. It is explanatory drawing which shows the supply condition of the cooling oil with respect to a housing. It is the schematic which shows a part of structure of the motor cooling device which is other embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a configuration of a motor cooling device 10 according to an embodiment of the present invention. In the illustrated motor cooling apparatus 10, two motor generators (electric motors) M1 and M2 mounted on the hybrid vehicle are to be cooled. As shown in FIG. 1, the hybrid vehicle includes an engine 11 as a drive source and two motor generators M1 and M2 as drive sources. The motor generator M1 mainly functions as a generator, and the motor generator M2 mainly functions as an electric motor. Further, the engine 11, the motor generator M1, and the motor generator M2 are connected to each other via a power split mechanism 12 constituted by a plurality of planetary gear trains. A drive wheel output shaft 14 is connected to the power split mechanism 12 via a gear train 13, and engine power and motor power are output from the drive wheel output shaft 14 to drive wheels (not shown).

  As shown in FIG. 1, the motor generator M <b> 1 is accommodated in the housing 15. A pair of supply oil passages 16 are connected to the upper portion of the housing 15, while a pair of discharge oil passages 17 are connected to the lower portion of the housing 15. Similarly, the motor generator M <b> 2 is accommodated in the housing 18. A pair of supply oil passages 19 are connected to the upper portion of the housing 18, while a pair of discharge oil passages 20 are connected to the lower portion of the housing 18. An upstream oil passage 21 is connected to each of the supply oil passages 16 and 19, and the upstream oil passage 21 is connected to a reservoir tank 23 via an electric oil pump 22. The reservoir tank 23 stores cooling oil X used for cooling the motor generators M1 and M2. Thus, the upstream oil passage 21 that is the supply path of the cooling oil X is provided with the electric oil pump 22 that functions as a supply-side adjustment mechanism. By controlling the rotational speed of the electric oil pump 22, the supply flow rate of the cooling oil X supplied to the housings 15 and 18 can be adjusted. Further, a downstream oil passage 24 is connected to each of the discharge oil passages 17 and 20, and the downstream oil passage 24 is connected to the reservoir tank 23 via an oil cooler 25. Further, variable oil restrictors 26 and 27 functioning as a discharge side adjusting mechanism are provided in the discharge oil passages 17 and 20 which are discharge paths of the cooling oil X. By controlling the flow passage areas of the variable throttle valves 26 and 27, the discharge flow rate of the cooling oil X discharged from the housings 15 and 18 can be adjusted. Further, an electric fan 28 that generates cooling air is installed opposite to the oil cooler 25.

  The motor generator M1 includes an annular stator 40 that is fixed to the housing 15 and a rotor 41 that is rotatably accommodated inside the stator 40. Further, a stator coil 42 is wound around the stator 40, and coil end portions 43 each including the stator coil 42 are provided at both ends of the stator 40 in the width direction. Furthermore, the supply oil passage 16 connected to the housing 15 opens above the coil end portion 43. Similarly, the motor generator M <b> 2 includes an annular stator 44 that is fixed to the housing 18, and a rotor 45 that is rotatably accommodated inside the stator 44. A stator coil 46 is wound around the stator 44, and a coil end portion 47 in which the stator coils 46 are gathered is provided at both ends of the stator 44 in the width direction. Further, the supply oil passage 19 connected to the housing 18 opens above the coil end portion 47. Further, an inverter 48 is connected to the stator coil 42 of the motor generator M1, and an inverter 49 is connected to the stator coil 46 of the motor generator M2. Further, a battery 50 is connected to both the inverters 48 and 49.

  The hybrid vehicle is provided with a control unit 51, and the engine 11, the motor generators M 1 and M 2, the electric oil pump 22 and the variable throttle valves 26 and 27 are controlled by the control unit 51. The control unit 51 includes an accelerator pedal sensor 52 for detecting an accelerator pedal depression amount (hereinafter referred to as an accelerator operation amount), a brake pedal sensor 53 for detecting a brake pedal depression amount (hereinafter referred to as a brake operation amount), and a vehicle speed. A vehicle speed sensor 54 for detecting, a gradient sensor 55 for detecting road surface gradient, and an outside air temperature sensor 56 for detecting outside air temperature are connected. The control unit 51 includes a cooling oil temperature sensor 57 that detects the temperature of the cooling oil X in the reservoir tank 23 (hereinafter referred to as cooling oil temperature To), a motor temperature sensor 58 that detects the temperature of the stator coil 42, a stator. A motor temperature sensor 59 for detecting the temperature of the coil 46 (hereinafter referred to as motor temperature Tm2), an oil level sensor 60 for detecting the oil level of the cooling oil X stored in the housing 15, and stored in the housing 18. An oil level sensor 61 or the like for detecting the oil level height of the cooling oil X is connected. The control unit 51 includes a CPU that calculates control signals and the like, a ROM that stores control programs, arithmetic expressions and map data, and a RAM that temporarily stores data.

  Such a control unit 51 outputs control signals to the inverters 48 and 49 based on the driver's accelerator operation and brake operation, and controls the operating states of the motor generators M1 and M2. The control unit 51 controls the operating state of the engine 11 by outputting a control signal to a throttle valve (not shown) based on the driver's accelerator operation and brake operation. Further, the control unit 51 controls the electric oil pump 22 and the variable throttle valves 26 and 27 based on the predicted heat generation amounts of the motor generators M1 and M2, and cools the motor generators M1 and M2 within a predetermined temperature range. ing. That is, by controlling the electric oil pump 22 and the variable throttle valves 26 and 27, the supply flow rate of the cooling oil X supplied to the housings 15 and 18 and the discharge flow rate of the cooling oil X discharged from the housings 15 and 18. Can be controlled. Thereby, while maintaining the oil level height in the housing 15 in a predetermined range, the circulating flow rate of the cooling oil X can be freely increased and decreased while maintaining the oil level height in the housing 18 in a predetermined range. Thus, by adjusting the cooling capacity of the motor cooling device 10 by increasing / decreasing the circulating flow rate of the cooling oil X, the motor generators M1, M2 can be cooled within a predetermined temperature range.

  Hereinafter, a procedure for cooling control of the motor generators M1 and M2 by the control unit (heat generation amount calculation unit, flow rate control unit) 51 will be described. FIG. 2 is a flowchart showing a control procedure of the electric oil pump 22 and the variable throttle valve 27 by the control unit 51. As described above, the hybrid vehicle is provided with two motor generators M1 and M2 as objects to be cooled, and the cooling oil X is supplied from one electric oil pump 22 to these motor generators M1 and M2. Yes. Therefore, the control unit 51 predicts the heat generation amount of the motor generators M1 and M2, and controls the electric oil pump 22 and the variable throttle valves 26 and 27 based on the predicted heat generation amount (hereinafter referred to as the predicted heat generation amount H). doing. That is, the control unit 51 performs cooling control on the motor generators M1 and M2. In the following description, the case where the heat generation amount of motor generator M2 is larger than the heat generation amount of motor generator M1 will be described as an example. In this case, the control of the variable throttle valve 26 provided on the motor generator M1 side is simplified by controlling according to the discharge flow rate of the electric oil pump 22 so as to keep the oil level in the housing 15 within a predetermined range. Can be

  As shown in FIG. 2, in step S1, a predetermined torque map is referred to based on the accelerator operation amount, the brake operation amount, and the vehicle speed, and the target torque (control target value) of the motor generator M2 is set. Here, FIGS. 3A and 3B are explanatory diagrams illustrating an example of a torque map referred to when setting the target torque. During acceleration in which the accelerator pedal is depressed by the driver, the torque map in FIG. 3A is referred to based on the accelerator operation amount and the vehicle speed. As shown in FIG. 3A, a plurality of characteristic lines A0 to A4 corresponding to the accelerator operation amount are set in the torque map. The characteristic line A0 is a characteristic line corresponding to the accelerator operation amount “0%”, the characteristic line A1 is a characteristic line corresponding to the accelerator operation amount “25%”, and the characteristic line A2 is the accelerator operation amount “50%”. The characteristic line A3 is a characteristic line corresponding to the accelerator operation amount “75%”, and the characteristic line A4 is a characteristic line corresponding to the accelerator operation amount “100%”. That is, the target torque of motor generator M2 is set to be larger on the positive side (powering side) as the accelerator pedal is depressed by the driver. On the other hand, during braking in which the brake pedal is depressed by the driver, the torque map in FIG. 3B is referred to based on the brake operation amount and the vehicle speed. As shown in FIG. 3B, a plurality of characteristic lines B1 to B4 corresponding to the brake operation amount are set in the torque map. The characteristic line B1 is a characteristic line corresponding to the brake operation amount “25%”, the characteristic line B2 is a characteristic line corresponding to the brake operation amount “50%”, and the characteristic line B3 is the brake operation amount “75%”. "And a characteristic line B4 is a characteristic line corresponding to the brake operation amount" 100% ". That is, the target torque of the motor generator M2 is set to be larger on the negative side (power generation side) as the brake pedal is depressed by the driver.

  In step S2, a predetermined efficiency map is referred to based on the target torque and the current motor rotation speed (motor rotation speed), and the predicted heat generation amount H of the motor generator M2 is calculated. Here, FIG. 4 is an explanatory diagram showing an example of an efficiency map referred to when the predicted heat generation amount H is calculated. As shown in FIG. 4, the efficiency map shows the efficiency of the motor generator M2 with the target torque and the motor rotation speed as parameters. The numerical values shown in the efficiency map of FIG. 4 mean the efficiency of the motor generator M2. The control unit 51 refers to the efficiency map of FIG. 4 based on the target torque and the motor rotation speed, and predicts the efficiency of the motor generator M2. Subsequently, when the target torque is set to the positive side, the control unit 51 calculates the predicted heat generation amount H based on the efficiency and power consumption of the motor generator M2. On the other hand, when the target torque is set to the negative side, the predicted heat generation amount H is calculated based on the efficiency of the motor generator M2 and the generated power. When the efficiency of the motor generator M2 is good, that is, when the loss of the motor generator M2 is small, the predicted heat generation amount H of the motor generator M2 is calculated to be small. On the other hand, when the efficiency of the motor generator M2 is poor, that is, when the loss of the motor generator M2 is large, the predicted heat generation amount H of the motor generator M2 is calculated to be large. When the power consumption or generated power of motor generator M2 is small, predicted heat generation amount H of motor generator M2 is calculated to be small. On the other hand, when the power consumption or generated power of motor generator M2 is large, predicted heat generation amount H of motor generator M2 is calculated to be large.

  In the above description, after obtaining the efficiency of the motor generator M2 using the efficiency map, the predicted heat generation amount H of the motor generator M2 is calculated using this efficiency. However, the present invention is not limited to this procedure. . For example, the predicted heat generation amount H may be directly calculated by creating a heat generation amount map by experiment or simulation and referring to the heat generation amount map. Further, since the motor generator M2 shown in the figure has a structure in which the rotation speed is interlocked with the vehicle speed, the motor generator M2 is controlled not by the target rotation speed but by the target torque. For this reason, when referring to the efficiency map, the current motor speed that is actually measured or calculated is used instead of the target speed. However, when the motor generator is controlled using the target rotational speed, the efficiency map and the heat generation amount map may be referred to based on the target rotational speed that is the control target value. When the motor generator is controlled using the target torque and the target rotational speed, the efficiency map and the heat generation amount map may be referred to based on the target torque and the target rotational speed, which are control target values.

  In step S3, the cooling capacity C of the motor cooling device 10 is set based on the temperature difference ΔT between the cooling oil temperature To and the motor temperature Tm2 and the calculated predicted heat generation amount H. The cooling capacity C is a cooling capacity required for the motor cooling device 10 and is set to a capacity that exceeds at least the predicted heat generation amount H. Subsequently, in step S4, a predetermined flow rate map is referred to based on the cooling capacity C, and the discharge flow rate of the electric oil pump 22, that is, the supply flow rate of the cooling oil X is set. When the supply flow rate is set in step S4, the control unit 51 executes the rotational speed control of the electric oil pump 22 based on the supply flow rate. Here, FIG. 5 is an explanatory diagram showing an example of a flow rate map referred to when setting the supply flow rate. As shown in FIG. 5, a plurality of characteristic lines T1 to T3 corresponding to the temperature difference ΔT are set in the flow rate map. When the temperature difference ΔT is large, the supply flow rate is set based on the characteristic line T1, while when the temperature difference ΔT is small, the supply flow rate is set based on the characteristic line T3. That is, when the temperature difference ΔT is large, the amount of heat taken into the cooling oil X is large. Therefore, the supply flow rate of the electric oil pump 22 is set to be small, whereas when the temperature difference ΔT is small, the cooling oil X is Since the amount of heat taken in is small, a large supply flow rate of the electric oil pump 22 is set. A value obtained by multiplying the temperature difference ΔT by the supply flow rate is proportional to the cooling capacity C (or the predicted heat generation amount H).

  In step S5, the flow passage area of the variable throttle valve 27 is set based on the supply flow rate and the predetermined oil level height. The predetermined oil level height used in step S5 is a target value of the oil level in the housing 18, and is set within a predetermined range where the rotor 45 of the motor generator M2 is not immersed in the cooling oil X. Yes. When the flow path area is set in step S5, the control unit 51 controls the variable throttle valve 27 based on the flow path area. Here, FIG. 6 is an explanatory diagram showing an example of an opening degree map that is referred to when setting the channel area. As shown in FIG. 6, a plurality of characteristic lines F1 to F3 corresponding to the supply flow rate are set in the opening degree map. When the supply flow rate is high, the flow path area is set based on the characteristic line F1, while when the supply flow rate is low, the flow path area is set based on the characteristic line F3. That is, when the supply flow rate is large, the flow area is set to be large in order to increase the discharge flow rate accordingly, whereas when the supply flow rate is small, the discharge flow rate is decreased accordingly The channel area is set small. As described above, with respect to the variable throttle valve 26 provided on the motor generator M1 side, the flow path area is controlled so that the oil level in the housing 15 is kept within a predetermined range. The target value of the oil level in the housing 15 is also set within a predetermined range in which the rotor 41 of the motor generator M1 is not immersed in the cooling oil X.

  Here, FIGS. 7A and 7B are explanatory views showing the supply state of the cooling oil X to the housing 18. FIG. 7A shows the supply status when the predicted heat generation amount H is small or when the temperature difference ΔT is large. FIG. 7B shows the supply status when the predicted heat generation amount H is large or when the temperature difference ΔT is small. In FIGS. 7A and 7B, the flow of the cooling oil X is indicated by white arrows. First, as shown in the flow rate map of FIG. 5 described above, when the cooling capacity C is small, that is, when the predicted heat generation amount H is small, the motor generator M2 can be sufficiently cooled with a small flow rate. The supply flow rate of 22 is controlled to the decreasing side. Even when the temperature difference ΔT between the cooling oil temperature To and the motor temperature Tm2 is large, the amount of heat absorbed by the cooling oil X is large, so that the supply flow rate of the electric oil pump 22 is controlled to the decreasing side. Furthermore, as shown in the opening degree map of FIG. 6, when the supply flow rate of the electric oil pump 22 is decreased, it is variable in order to avoid a decrease in the oil level of the cooling oil X stored in the housing 18. The throttle valve 27 is controlled to the throttle side, and the discharge flow rate of the cooling oil X is reduced. Thus, when the predicted heat generation amount H is small or when the temperature difference ΔT is large, the supply flow rate and the discharge flow rate of the cooling oil X are controlled to the decreasing side. As a result, as shown in FIG. 7A, the circulating flow rate of the cooling oil X circulating between the housing 18 and the reservoir tank 23 is reduced while the oil level in the housing 18 is maintained at a predetermined value L1. It becomes possible to make it.

  As described above, when the motor generator M2 is easily cooled, the circulation flow rate can be reduced to reduce the load on the electric oil pump 22, so that the energy required for cooling can be suppressed. . In addition to reducing the load on the electric oil pump 22 simply by reducing the supply flow rate, the discharge flow rate is reduced to maintain the oil level height in the housing 18 at a predetermined value L1. Thereby, since the lower part of the stator coil 46 can always be immersed in the cooling oil X, the circulating flow rate of the cooling oil X can be further reduced while maintaining the cooling performance. Further, by performing the cooling control using the predicted heat generation amount H, the circulation flow rate can be reduced in advance in a vehicle situation where the motor temperature Tm2 is lowered. Also from these points, the load on the electric oil pump 22 can be reduced, so that the motor generator M2 can be appropriately cooled while suppressing energy.

  On the other hand, as shown in the flow map of FIG. 5, when the cooling capacity C is large, that is, when the predicted heat generation amount H is large, a large amount of cooling oil X is required for cooling the motor generator M2, and therefore the electric oil pump 22 Is controlled to increase. Even when the temperature difference ΔT between the cooling oil temperature To and the motor temperature Tm2 is small, the amount of heat absorbed by the cooling oil X is small, so that the supply flow rate of the electric oil pump 22 is controlled to the increase side. Further, as shown in the opening degree map of FIG. 6, when the supply flow rate of the electric oil pump 22 is increased, it is variable in order to avoid an increase in the oil level of the cooling oil X stored in the housing 18. The throttle valve 27 is controlled to the open side, and the discharge flow rate of the cooling oil X is controlled to the increase side. Thus, when the predicted heat generation amount H is large or when the temperature difference ΔT is small, the supply flow rate and the discharge flow rate of the cooling oil X are controlled to the increase side. As a result, as shown in FIG. 7B, the circulating flow rate of the cooling oil X circulated between the housing 18 and the reservoir tank 23 is increased while the oil level in the housing 18 is maintained at a predetermined value L1. It becomes possible to make it.

  Thus, when it becomes difficult to cool the motor generator M2, the motor generator M2 can be appropriately cooled by increasing the circulating flow rate of the cooling oil X. Further, by performing cooling control using the predicted heat generation amount H, in a vehicle situation in which the motor temperature Tm2 increases, the circulation flow rate can be increased in advance, and an excessive temperature increase of the motor generator M2 is prevented in advance. It becomes possible to do. In addition, by maintaining the oil level in the housing 18 at the predetermined value L1, the cooling performance of the motor generator M2 can be improved, and the stirring of the cooling oil X that causes an increase in the rotational resistance of the rotor 45 can be avoided. It becomes possible.

  7A and 7B, the supply oil passage 16 of the housing 15 is opened above the coil end portion 43, and the supply oil passage 19 of the housing 18 is above the coil end portion 47. Is open. As a result, the cooling oil X flowing out from the supply oil passages 16 and 19 serving as supply passages into the housings 15 and 18 is dropped onto the coil end portions 43 and 46 and then travels around the outer periphery of the coil end portions 43 and 46. It will flow downward. Thus, the cooling oil X can be reliably supplied to the coil end portions 43 and 46 that are at the highest temperature, and the cooling performance of the motor cooling device 10 can be improved.

  Next, another procedure for controlling the cooling of the motor generators M1 and M2 by the control unit 51 will be described. FIG. 8 is a flowchart showing another control procedure of the electric oil pump 22 and the variable throttle valve 27 by the control unit 51. In FIG. 8, the same steps as those shown in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted. As shown in FIG. 8, when the electric oil pump 22 is controlled in step S4 and the variable throttle valve 27 is controlled in step S5, the process proceeds to step S6, and the cooling oil temperature To and the oil level are evaluated. In step S6, if the cooling oil temperature To is out of the predetermined range, or the oil level height is out of the predetermined range, in the subsequent step S7, the supply flow rate is corrected and the electric oil pump 22 is controlled again. In subsequent step S8, the flow passage area is corrected and the variable throttle valve 27 is controlled again.

  That is, in step S6, when it is determined that the cooling oil temperature To exceeds the predetermined upper limit, the electric oil pump 22 and the variable throttle valve 27 are controlled so as to increase the supply flow rate and the discharge flow rate. On the other hand, when it is determined that the cooling oil temperature To is below the predetermined lower limit, the electric oil pump 22 and the variable throttle valve 27 are controlled so as to decrease the supply flow rate and the discharge flow rate. In Step S6, when it is determined that the oil level height exceeds the predetermined upper limit, the electric oil pump 22 is controlled to decrease the supply flow rate, and the variable throttle valve 27 is set to increase the discharge flow rate. Be controlled. On the other hand, when it is determined that the oil level is below the predetermined lower limit, the electric oil pump 22 is controlled to increase the supply flow rate, and the variable throttle valve 27 is controlled to decrease the discharge flow rate.

  As described above, the feedback control of the electric oil pump 22 and the variable throttle valve 27 is performed while determining the cooling oil temperature To and the oil surface height, thereby performing the control accuracy while performing the feedforward control based on the predicted heat generation amount H. Can be increased. In the above description, the supply flow rate and the discharge flow rate are adjusted when raising and lowering the oil level, but the present invention is not limited to this. For example, when lowering the oil level, only the supply flow rate may be decreased or only the discharge flow rate may be increased. Moreover, when raising the oil level, only the supply flow rate may be increased or only the discharge flow rate may be decreased. In the above description, the supply flow rate and the discharge flow rate are controlled based on the cooling oil temperature To, but the present invention is not limited to this, and the supply flow rate and the discharge flow rate may be controlled based on the motor temperature Tm2.

  As shown in FIG. 1, a gradient sensor 55 is connected to the control unit 51, and a road surface gradient during traveling is input to the control unit 51. Therefore, the control unit 51 controls the electric oil pump 22 and the variable throttle valve 27 according to the road surface gradient from the viewpoint of suppressing the rotational resistance of the motor generator M2. Note that the transaxle is mounted vertically on the hybrid vehicle, and the rotation shafts of the motor generators M1, M2 are in the traveling direction. That is, the road surface gradient output from the gradient sensor 55 is information indicating the inclination angles of the motor generators M1 and M2.

  Here, FIGS. 9A and 9B are explanatory views showing the supply state of the cooling oil X to the housing 18. As shown in FIG. 9A, when the road surface gradient is changed and the housing 18 is inclined, the cooling oil X stored in the housing 18 is shifted to one side, so that the rotor 45 may agitate the cooling oil X. There is. Therefore, when a road surface gradient exceeding a predetermined value is detected, the control unit 51 controls the electric oil pump 22 and the variable throttle valve 27 as shown by an arrow α in FIG. The oil level is lowered to a position where the cooling oil X does not contact the cooling oil X. Thereby, stirring of cooling oil X by rotor 45 can be avoided, and an increase in rotational resistance of motor generator M2 can be suppressed. In the above description, the gradient sensor 55 is used. However, the present invention is not limited to this, and an inclination angle sensor that detects the inclination angles of the motor generators M1 and M2 may be used. Further, when the oil level height is lowered, the supply flow rate may be decreased and the discharge flow rate may be increased, only the supply flow rate may be decreased, or only the discharge flow rate may be increased. That is, when the cooling oil X in the housing 18 is decreased, at least one of the supply flow rate decrease control and the discharge flow rate increase control may be executed.

  As shown in FIG. 1, an outside air temperature sensor 56 is connected to the control unit 51, and the outside air temperature is input to the control unit 51. Therefore, the control unit 51 performs the rotational speed control of the electric fan 28 based on the outside air temperature and the cooling oil temperature To from the viewpoint of improving the cooling performance of the motor cooling device 10. That is, when the outside air temperature is lower than a predetermined value or when the cooling oil temperature To is lower than the predetermined value, the electric fan 28 is stopped or controlled at a low rotational speed to reduce the cooling air volume and reduce the oil cooler. The heat radiation amount of 25 is reduced. On the other hand, when the outside air temperature is higher than the predetermined value or when the cooling oil temperature To is higher than the predetermined value, the electric fan 28 is controlled at a high speed, thereby increasing the cooling air volume and releasing the oil cooler 25. The amount of heat is raised. As a result, the load of electric fan 28 can be adjusted according to the heat generation status of motor generators M1 and M2, so that motor generators M1 and M2 can be appropriately cooled while suppressing energy. Note that the rotational speed control of the electric fan 28 may be executed based on the motor temperature Tm2.

  In the above description, the oil level is adjusted to a position where the rotor 45 does not contact the cooling oil X in order to suppress an increase in the rotational resistance of the motor generator M2. However, when the predicted heat generation amount H is excessively large, the motor generator M2 may be actively cooled by raising the oil level. Here, FIG. 10 is an explanatory view showing a supply state of the cooling oil X to the housing 18. As indicated by an arrow α in FIG. 10, when the predicted heat generation amount H is excessively large or the motor temperature Tm2 is excessively high, the electric oil pump 22 and the variable throttle valve 27 are controlled to control the rotor 45. The oil level is raised beyond the lower end. Thereby, since most of the stator coils 46 can be immersed in the cooling oil X, the cooling performance of the motor cooling device 10 can be significantly increased. When the oil level is raised, the rotational resistance of motor generator M2 increases, so it is desirable to allow the oil level to be raised when the number of revolutions of motor generator M2 is low.

  Next, a motor cooling device 70 according to another embodiment of the present invention will be described. FIG. 11 is a schematic view showing a part of the configuration of a motor cooling device 70 according to another embodiment of the present invention. In FIG. 11, the same members as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. In the above description, the rotational speed of the electric oil pump 22 is controlled to adjust the supply flow rate of the cooling oil X, and the flow area of the variable throttle valves 26 and 27 is controlled to adjust the discharge flow rate of the cooling oil X. However, it is not limited to this. As shown in FIG. 11, an oil pump 71 that is driven by the crankshaft of the engine 11 is provided in the upstream oil passage 21 that connects the housings 15 and 18 and the reservoir tank 23. Further, a bypass oil passage 72 that bypasses the oil pump 71 is connected to the upstream oil passage 21, and a switching valve 73 is provided in the bypass oil passage 72. As described above, even if the oil pump 71 is difficult to control the rotational speed, the supply flow rate of the cooling oil X can be increased by shutting off the switching valve 73 of the bypass oil passage 72. By opening the valve 73, the supply flow rate of the cooling oil X can be reduced. That is, the supply side adjustment mechanism 74 is configured by the oil pump 71, the bypass oil passage 72, and the switching valve 73. Further, a switching valve 75 is provided on one side of the drain oil passage 17 connected to the housing 15. Similarly, a switching valve 76 is provided on one side of the discharge oil passage 20 connected to the housing 18. Even in such a configuration, the discharge flow rate of the cooling oil X can be reduced by shutting off the switching valves 75 and 76, and the discharge flow rate of the cooling oil X can be increased by opening the switching valves 75 and 76. Is possible. That is, the discharge oil path 17 and the switching valve 75 constitute a discharge side adjustment mechanism 77, and the discharge oil path 20 and the switching valve 76 constitute a discharge side adjustment mechanism 78. As described above, even when the supply side adjustment mechanism 74 and the discharge side adjustment mechanisms 77 and 78 are configured by the switching valves 73, 75 and 76, the supply flow rate and the discharge flow rate of the cooling oil X can be controlled. Therefore, it is possible to obtain the same effect as that of the motor cooling device 10 described above.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the illustrated motor cooling devices 10 and 70, two motor generators M1 and M2 are targeted for cooling. However, the present invention is not limited to this, and one electric motor may be targeted for cooling. The motor may be a cooling target. In the above description, the cooling oil X is supplied from one electric oil pump 22 or oil pump 71 to the two motor generators M1 and M2. However, the present invention is not limited to this. A dedicated oil pump may be provided for generators M1 and M2. Furthermore, in the above description, the motor cooling devices 10 and 70 are applied to a hybrid vehicle (vehicle). However, the present invention is not limited to this, and the motor cooling devices 10 and 70 of the present invention are driven only by an electric motor. You may apply to the electric vehicle (vehicle) provided as. In addition, although an example of each map used for cooling control is shown in FIGS. 3-6, it is not restricted to these maps, It changes suitably according to a specification etc. to the electric motor used as cooling object. Needless to say.

  In the above description, the electric oil pump 22 and the variable throttle valves 26 and 27 are controlled based on the predicted heat generation amount H of the motor generator M2, but the present invention is not limited to this. For example, the electric oil pump 22 and the variable throttle valves 26 and 27 may be controlled based on the predicted heat generation amount of the motor generator M1. Alternatively, the predicted heat generation amount of the motor generator M1 and the predicted heat generation amount of the motor generator M2 may be added together, and the electric oil pump 22 and the variable throttle valves 26 and 27 may be controlled based on the calculated predicted heat generation amount H. Needless to say, the cooling oil X may be used not only for cooling the motor generators M1 and M2, but also for lubrication of gears and hydraulic oil for clutches and the like.

DESCRIPTION OF SYMBOLS 10 Motor cooling device 15 Housing 16 Supply oil path (supply path)
17 Discharge oil passage (discharge passage)
18 Housing 19 Supply oil path (Supply path)
20 Discharge oil path (discharge path)
21 Upstream oil passage (supply route)
22 Electric oil pump (Supply side adjustment mechanism)
26 Variable throttle valve (Discharge side adjustment mechanism)
27 Variable throttle valve (Discharge side adjustment mechanism)
42 Stator coil 43 Coil end portion 46 Stator coil 47 Coil end portion 51 Control unit (heat generation amount calculation unit, flow rate control unit)
70 Motor Cooling Device 74 Supply Side Adjustment Mechanism 77 Discharge Side Adjustment Mechanism 78 Discharge Side Adjustment Mechanism M1 Motor Generator (Electric Motor)
M2 motor generator (electric motor)
X Cooling oil H Predicted calorific value ΔT Temperature difference

Claims (5)

A motor cooling device for cooling an electric motor mounted on a vehicle,
A housing that houses the electric motor;
A supply side adjustment mechanism that is provided in a supply path for supplying cooling oil to the housing and adjusts a supply flow rate of the cooling oil;
A discharge side adjusting mechanism that is provided in a discharge path for discharging the cooling oil from the housing and adjusts a discharge flow rate of the cooling oil;
A calorific value calculation unit that calculates a predicted calorific value of the electric motor based on a control target value of the electric motor;
A flow rate control unit that controls the supply side adjustment mechanism and the discharge side adjustment mechanism based on the predicted heat generation amount;
The flow rate control unit increases or decreases the supply flow rate and the discharge flow rate based on the predicted calorific value, thereby maintaining the oil level height of the cooling oil immersed in the electric motor within a predetermined range while circulating the cooling oil circulation flow rate Motor cooling device characterized by increasing or decreasing the amount. The motor cooling device according to claim 1,
The flow rate control unit increases the supply flow rate and the exhaust flow rate to increase the circulation flow rate when the predicted heat generation amount increases, while the supply flow rate when the predicted heat generation amount decreases. And a motor cooling device that reduces the circulation flow rate by reducing the discharge flow rate. The motor cooling device according to claim 1 or 2,
The cooling oil supplied into the housing from the supply path is supplied to the coil end portion of the stator coil of the electric motor and flows downward along the outer periphery of the coil end portion. In the motor cooling device according to any one of claims 1 to 3,
When the temperature difference between the cooling oil and the electric motor decreases, the flow rate controller increases the supply flow rate and the discharge flow rate to increase the circulation flow rate, while the temperature difference increases. In the motor cooling device, the circulating flow rate is decreased by decreasing the supply flow rate and the discharge flow rate. In the motor cooling device according to any one of claims 1 to 4,
The flow rate control unit executes at least one of the supply flow rate decrease control and the exhaust flow rate increase control when the electric motor is tilted beyond a predetermined value, and supplies the cooling oil in the housing. A motor cooling device characterized by being reduced.

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