Vehicle drive unit

Abstract

Disclosed is a vehicular drive device comprising a case, a power transmission mechanism that is positioned in the case and is supplied with oil, a rotary electric machine that is positioned radially outward of the power transmission mechanism in the case and has a stator coil at a position at which with the oil supplied to the power transmission mechanism is encountered, and a processing device that calculates the temperature of the stator coil on the basis of the loss in the rotary electric machine and the loss in the power transmission mechanism.

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle drive device. [Background technology]

[0002] There is known a technique for arranging a rotating electric machine radially outside a power transmission mechanism inside a case (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-151010 Summary of the Invention [Problem to be solved by the invention]

[0004] However, since the oil supplied to the power transmission mechanism is heated by losses in the power transmission mechanism, in a configuration in which a rotating electric machine is disposed radially outward of the power transmission mechanism, the oil heated by the power transmission mechanism may come into contact with the stator coil of the rotating electric machine. Therefore, with the above-described conventional technology, it is difficult to accurately calculate the temperature of the stator coil in a configuration in which a rotating electric machine is disposed radially outward of the power transmission mechanism.

[0005] Therefore, in one aspect, an object of the present disclosure is to accurately calculate the temperature of a stator coil in a configuration in which a rotating electric machine is disposed radially outside a power transmission mechanism. [Means for solving the problem]

[0006] In one aspect, the case and a power transmission mechanism disposed within the case and supplied with oil; a rotating electric machine having a stator coil disposed radially outside the power transmission mechanism in the case and positioned so as to be exposed to oil supplied to the power transmission mechanism; The vehicle drive system includes a processing device that calculates the temperature of the stator coil based on the loss in the rotating electric machine and the loss in the power transmission mechanism. [Effects of the Invention]

[0007] According to one aspect of the present disclosure, in a configuration in which a rotating electric machine is disposed radially outside a power transmission mechanism, it is possible to accurately calculate the temperature of a stator coil. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a skeleton diagram showing an entire drive system including a hybrid drive device according to an embodiment of the present invention. [Figure 2] 1 is a cross-sectional view showing a part of a hybrid drive device according to an embodiment of the present invention. [Figure 3] FIG. 2 is a block diagram showing an example of a processing device that realizes a coil temperature calculation function. [Figure 4] FIG. 4 is an explanatory diagram of a map used in a correction temperature calculation unit. [Figure 5] FIG. 10 is a block diagram showing an example of a processing device that realizes a coil temperature calculation function according to a first modified example. [Figure 6] FIG. 10 is a block diagram showing an example of a processing device that realizes a coil temperature calculation function according to a second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Each embodiment will be described in detail below with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples and are not intended to limit the scope of the invention. In addition, shapes and the like in the drawings may be partially exaggerated for the sake of explanation.

[0010] The hybrid drive system according to this embodiment will be described below with reference to Figures 1 and 2. The hybrid drive system according to this embodiment is suitable for installation in a vehicle of the FF (front engine, front drive) type, for example, and the left and right directions in Figures 1 and 2 correspond to the left and right directions (or the opposite left and right directions) when the hybrid drive system is actually installed in the vehicle, but for ease of explanation, the right side in the figures, which is the side of the drive source such as an engine, will be referred to as the "front side," and the left side in the figures will be referred to as the "rear side."

[0011] [Schematic configuration of hybrid drive system] 1, a vehicle 100 has a rotating electric machine (motor-generator) 3 (MG) in addition to an engine 2 (EG) as a drive source, and a hybrid drive system 1 as a vehicle drive system constituting the powertrain of the vehicle 100 is disposed in a power transmission path between the engine 2 and left and right drive shafts 72L, 72R that are drivingly connected to left and right wheels 90L, 90R. The hybrid drive system 1 includes, in this order from the engine 2 side in the power transmission path, an input unit 5 to which power from the engine 2 is input, a speed change mechanism 50 (TM) that changes the rotation from the input unit 5, a countershaft 60 that reverses the rotation of the speed change mechanism 50, and a differential unit 70 that transmits the rotation of the countershaft 60 to the wheels 90L, 90R via the drive shafts 72L, 72R while absorbing the differential rotation of the left and right wheels 90L, 90R.

[0012] An output shaft (crankshaft) 2a of the engine 2 is drivingly connected to an input shaft 1a of the hybrid drive unit 1, and the input shaft 1a serves as an input member of the engine 2 for the input section 5. Although not shown, a damper device that absorbs pulsation of the engine 2 is interposed between the input shaft 1a and the clutch K0 in the power transmission path.

[0013] The input unit 5 is equipped with a clutch K0 as a first clutch, a rotating electric machine (hereinafter simply referred to as "motor") 3, and a clutch WSC as a second clutch. The clutch K0 is interposed between the engine 2 and the motor 3 in the power transmission path, and in an engaged state, the engine 2 is drivingly connected to the motor 3, and in a released state, the engine 2 is disconnected from the motor 3; in other words, the clutch K0 is configured as an engine disconnecting clutch that disconnects the driving force of the engine 2 from the hybrid drive system 1. The clutch K0 is engaged when the driving force of the engine 2 is used, and is released when the driving force of the motor 3 is used without using the driving force of the engine 2; in other words, the clutch K0 functions as a drive pattern switching clutch that switches the pattern in which the driving force is output as a drive source.

[0014] The motor 3 is configured with a stator 10 and a rotor 20, and the rotor 20 is drivingly connected to the clutch K0 and also to the clutch WSC. The clutch WSC is interposed in a power transmission path between the rotor 20 of the motor 3 and an input shaft 50a, which serves as an input member of the transmission mechanism 50. When engaged, the clutch WSC transmits the driving force of one or both of the engine 2 and the motor 3 to the transmission mechanism 50, and when disengaged, does not transmit the driving force of one or both of the engine 2 and the motor 3 to the transmission mechanism 50. The clutch WSC functions as a starting clutch that is disengaged when the vehicle 100 stops so that the engine 2 does not stop when the wheels 90L, 90R stop rotating, and that slips and engages when the vehicle 100 starts, starting the vehicle 100. In the case of so-called EV driving, in which the vehicle 100 is driven using the driving force of the motor 3, the clutch K0 is released, and therefore the clutch WSC is brought into an engaged state.

[0015] The input unit 5 configured as described above functions as a drive pattern switching unit that switches the pattern for outputting the drive force of the drive source, and also functions as a starting device that starts the vehicle in place of a fluid transmission device such as a torque converter.

[0016] The transmission mechanism 50 has a function of changing the gear ratio between the rotation from the input unit 5 (rotation of the drive source) and the rotation of the wheels 90L, 90R. That is, the rotation input to the input shaft 50a is changed in speed by a gear mechanism or the like (not shown) and output from the counter gear 51. Note that the transmission mechanism 50 may be any type of transmission mechanism, such as a stepped transmission mechanism having a gear mechanism in which a plurality of planetary gears or the like are combined, a belt-type or toroidal-type continuously variable transmission mechanism, or even a transmission mechanism in which a stepped gear and a continuously variable transmission mechanism are combined.

[0017] The countershaft 60 has a drive shaft 61 and a large-diameter gear 62 and a small-diameter gear 63 fixed to the drive shaft 61, and the large-diameter gear 62 meshes with the counter gear 51 of the transmission mechanism 50. Rotation input from the counter gear 51 to the large-diameter gear 62 is output to the small-diameter gear 63 via the drive shaft 61. The differential device 70 has a differential ring gear 71 meshing with the small-diameter gear 63, and rotation input from the small-diameter gear 63 to the differential ring gear 71 is output to left and right drive shafts 72L, 72R via a differential gear mechanism (not shown) and then to left and right wheels 90L, 90R. As a result, the drive rotation of one or both of the engine 2 and the motor 3 is output to the wheels 90L, 90R while being speed-shifted by the transmission mechanism 50. In other words, the rotation of the drive source is shifted in accordance with the vehicle speed and required driving force, allowing the vehicle 100 to travel efficiently.

[0018] [Input details] Next, a detailed structure of the input unit 5, which is a part of the hybrid drive system 1, will be described with reference to FIG. 2. As shown in FIG. 2, the input unit 5 of the hybrid drive system 1 is disposed in a space enclosed by a cylindrical portion 6a of the case 6, a first partition wall 6d on the front side, and a second partition wall 6b on the rear side. An input shaft 1a of the hybrid drive system 1 is rotatably supported by the first partition wall 6d of the case 6 via a ball bearing B1. An input shaft 50a of a transmission mechanism 50 is rotatably fitted in a hollow portion formed in the input shaft 1a. The input shaft 50a is further rotatably supported by a boss portion 6c extending in a boss-like shape from the second partition wall 6b. The input shaft 1a and the input shaft 50a form a central axis of the input unit 5. A clutch K0 and a clutch WSC are arranged axially on the outer peripheries of the input shaft 1a and the input shaft 50a. A motor 3 is further arranged on the outer periphery of the clutch K0 and the clutch WSC.

[0019] A hollow, disc-shaped end plate 39 is fixed to the rear end of the input shaft 1a, and a hub member 38 is fixed to the end plate 39. An inner friction plate among the plurality of friction plates 31 of the clutch K0 is spline-engaged with the hub member 38, and one of the end plates 39 restricts axial movement of the friction plates 31 when they are pressed by a hydraulic servo 30, which will be described later.

[0020] The clutch K0 includes the plurality of friction plates 31 and a hydraulic servo 30 that engages or disengages the friction plates 31. An outer friction plate of the plurality of friction plates 31 is spline-engaged to splines 42Bs formed on a cylindrical portion 42B of a rotor hub 42 (described later). The hydraulic servo 30 includes a cylinder member 32 that constitutes a hydraulic cylinder, a piston member 33 that is axially movable relative to the cylinder member 32 and has a tip end facing the friction plates 31, a cancel plate 34 that is axially positioned relative to an end plate 39 (and the input shaft 1a), and a return spring 35 that is disposed between the piston member 33 and the cancel plate 34. A hydraulic oil chamber 36 is formed between the cylinder member 32 and the piston member 33, and a cancel oil chamber 37 that cancels the centrifugal hydraulic pressure of the hydraulic oil chamber 36 is formed between the piston member 33 and the cancel plate 34.

[0021] Meanwhile, the rotor hub 42 includes a cylinder member 42A that constitutes a hydraulic cylinder of the hydraulic servo 40 (described later) and a cylindrical portion 42B fixed to the cylinder member 42A, and is rotatably supported by the boss portion 6c of the case 6 via a ball bearing B2, and is rotatably supported by the first partition wall portion 6d of the case 6 via a ball bearing B3. Splines 42Bs are formed on the inner periphery of the cylindrical portion 42B, and a splined drum member 49 is splined to the splines 42Bs. Furthermore, an outer friction plate of the plurality of friction plates 41 of the clutch WSC is splined to the inner periphery of the drum member 49. An end plate 48 is splined to the splines 42Bs of the cylindrical portion 42B between the friction plate 41 and the end plate 39, and the end plate 48 is restricted by a snap ring SN1 so as to be immovable forward in the axial direction.

[0022] The clutch WSC includes the plurality of friction plates 41 and a hydraulic servo 40 that engages or disengages (engages or releases) the friction plates 41. An inner friction plate of the plurality of friction plates 41 is spline-engaged to a hub member 53 that is fixed to a connecting member 52 that is spline-engaged to an input shaft 50a. The hydraulic servo 40 includes a cylinder member 42A that constitutes a hydraulic cylinder, a piston member 43 that is axially movable relative to the cylinder member 42A and has a tip end that faces the friction plates 41, a cancel plate 44 that is axially positioned relative to the cylinder member 42A, and a return spring 45 that is disposed between the piston member 43 and the cancel plate 44. A hydraulic oil chamber 46 is formed between the cylinder member 42A and the piston member 43, and a cancel oil chamber 47 that cancels the centrifugal hydraulic pressure of the hydraulic oil chamber 46 is formed between the piston member 43 and the cancel plate 44.

[0023] The rotor 20 of the motor 3 is fixed to the outer periphery of the cylindrical portion 42B of the rotor hub 42. The rotor 20 includes a rotor core 21 formed by stacking laminated steel plates 21a in the axial direction, magnets 22 inserted into and fixed in slots in the rotor core 21, and a first end plate 23 and a second end plate 24 disposed on both axial sides of the rotor core 21 to prevent the magnets 22 from falling out of the slots in the rotor core 21. A circumferential hole 42Ba is formed in the cylindrical portion 42B on the outer periphery of the clutch K0 at a position overlapping with the clutch K0 in the axial direction as viewed from the circumferential direction. The oil passage structure for guiding cooling oil from this circumferential hole 42Ba will be described later.

[0024] A stator 10 is disposed facing the outer periphery of the rotor 20. The stator 10 is configured to include a stator core 11 having a plurality of teeth formed thereon, and a plurality of stator coils 12 arranged to pass through slots between the teeth of the stator core 11, with the plurality of stator coils 12 protruding from both sides of the stator core 11 in the axial direction to form first coil ends 12Ea and second coil ends 12Eb.

[0025] A sprocket 81 is splined to the rear side of the rotor hub 42, and a sprocket 83 splined to a drive shaft 84 of an oil pump (not shown) is disposed on another axis parallel to the rotor hub 42 (input shaft 50a) and rotatably supported by ball bearings B4 relative to the case 6, with a chain 82 suspended between the sprockets 81 and 83. As a result, the driving rotation of the rotor hub 42 is transmitted to the drive shaft 84 of the oil pump, and the oil pump (not shown) is driven in conjunction with the rotor hub 42 (motor 3).

[0026] [Hydraulic supply details] Next, the supply of each hydraulic pressure will be described in detail. The hydraulic pressure of the clutch K0 is supplied from a hydraulic control device (not shown) to an oil passage (not shown) in the boss portion 6c of the case 6, and then is conducted from an oil passage (not shown) in the input shaft 50a to an oil passage a11 and then to the hydraulic oil chamber 36 through an oil passage a12 in the input shaft 1a. This causes the piston member 33 to move against the biasing force of the return spring 35, pressing against the friction plates 31 and engaging the clutch K0. When the clutch K0 is engaged, the input shaft 1a, end plate 39, and hub member 38 are drivably coupled to the rotor hub 42, i.e., the engine 2 and the motor 3 are drivably coupled as described above. Furthermore, when the hydraulic pressure in the hydraulic oil chamber 36 is reduced, the biasing force of the return spring 35 releases the piston member 33 from pressing against the friction plates 31, and the clutch K0 is released. This disengages the drivably coupled between the engine 2 and the motor 3.

[0027] The hydraulic oil pressure for the clutch WSC is supplied from a hydraulic control device (not shown) to an oil passage a21 in the boss portion 6c of the case 6, then to an oil passage a22, and then to the hydraulic oil chamber 46 through an oil passage a23 in the rotor hub 42. This causes the piston member 43 to move against the biasing force of the return spring 45, pressing against the friction plates 41 and engaging the clutch WSC. When the clutch WSC is engaged, the rotor hub 42 and the drum member 49 are drivingly connected to the hub member 53 and the connecting member 52, which means that the motor 3 (and the engine 2 when the clutch K0 is engaged) and the input shaft 50a of the transmission mechanism 50 are drivingly connected, as described above. In particular, when the vehicle 100 starts, the axial position of the piston member 43 is controlled by the magnitude of the hydraulic oil pressure against the biasing force of the return spring 45, causing the friction plates 41 to slip-engage. This allows the driving force of one or both of the motor 3 and the engine 2 to be gradually transmitted to the transmission mechanism 50, allowing the vehicle 100 to start moving smoothly.

[0028] On the other hand, when the hydraulic oil pressure in the hydraulic oil chamber 46 is reduced, the biasing force of the return spring 45 releases the piston member 43 from pressing the friction plate 41, and the clutch WSC is released. This releases the driving connection between the motor 3 (and the engine 2 when the clutch K0 is engaged) and the input shaft 50a of the transmission mechanism 50. In particular, when the clutch K0 is engaged, even if the vehicle 100 stops and the rotation of the input shaft 50a stops, the rotation of the input shaft 1a is not stopped by releasing the clutch WSC, i.e., the engine 2 is not stopped, and the vehicle 100 can be stopped.

[0029] [Cooling oil supply] Next, the supply of lubricating oil (cooling oil) will be described. Lubricating oil for the clutch WSC is supplied from a hydraulic control device (not shown) to an oil passage (not shown) in the boss portion 6c of the case 6, and then to the cancel oil chamber 47 via an oil passage (not shown) in the rotor hub 42. When the cancel oil chamber 47 is filled with lubricating oil, the lubricating oil overflowing from the cancel oil chamber 47 is guided from between the front end of the rotor hub 42 and the connecting member 52 to the inner periphery of the friction plates 41 and supplied to the friction plates 41 by centrifugal force. The lubricating oil supplied to the friction plates 41 is discharged to the outer periphery of the drum member 49 and guided to the splines 42Bs of the cylindrical portion 42B of the rotor hub 42. The forward flow is blocked by the snap ring SN1, and the lubricating oil is discharged rearward from a hole (not shown) formed in the cylinder member 42A of the rotor hub 42 and returned to the oil pan (not shown).

[0030] Lubricating oil for the clutch K0 is supplied from a hydraulic control device (not shown) to an oil passage (not shown) in the boss portion 6c of the case 6, passes through oil passages a1, a2, and a3 in the input shaft 50a and oil passage a4 in the input shaft 1a, and is supplied to the cancel oil chamber 37. When the cancel oil chamber 37 is filled with lubricating oil, the lubricating oil that overflows from the cancel oil chamber 37 is guided between the cancel plate 34 and the end plate 39 and is supplied by centrifugal force to the friction plates 31. The lubricating oil supplied to the friction plates 31 is discharged to the splines 42Bs in the cylindrical portion 42B of the rotor hub 42, and is introduced into a plurality of circumferential holes 42Ba that are formed penetrating the cylindrical portion 42B in the inner and outer circumferential directions from the inner circumferential surface to the outer circumferential surface at positions in different phases in the circumferential direction of the cylindrical portion 42B. The circumferential hole 42Ba is formed at a position where the distance from its center to the axial front end (one side) of the rotor 20 is shorter than the distance to the axial rear end (the other side) of the rotor 20; in other words, in this embodiment, the circumferential hole 42Ba of the cylindrical portion 42B of the rotor hub 42 is not formed in the axial center with respect to the rotor 20.

[0031] [Coil temperature calculation function] Next, a processing device having a coil temperature calculation function suitable for the hybrid drive system 1 described above will be described with reference to FIG. 3 and subsequent figures.

[0032] The coil temperature calculation function described below is suitable for the hybrid drive system 1 described above, but the detailed configuration of the hybrid drive system 1 may differ from that described above, and the function can also be applied to various drive systems other than the hybrid drive system 1. For example, the coil temperature calculation function described below can also be applied to a drive system that does not include an engine. Specifically, the coil temperature calculation function described below can be applied to any drive system as long as the drive system has a rotating electric machine disposed radially outside a power transmission mechanism within the case 6. In this case, the power transmission mechanism does not have to be a mechanism that transmits power from a power source (for example, the motor 3) to wheels, but may be a mechanism that transmits power to another driven object.

[0033] 3 is a block diagram showing an example of a processing device 90 that realizes the coil temperature calculation function. The processing device 90 may be realized by a processing device that controls the motor 3 described above. The processing device 90 may be realized by a computer such as a microcomputer. In FIG. 3, the left side of line L1 represents input to the processing device 90, and the right side of line L2 represents output from the processing device 90, with the configuration between lines L1 and L2 being realized by the processing device 90.

[0034] As shown in FIG. 3, the processing device 90 includes a motor loss calculation unit 900, a cooling ON / OFF determination unit 902, a coil temperature estimation unit 904, a filter 906, and a correction temperature calculation unit 908.

[0035] The motor loss calculation unit 900 calculates the loss in the motor 3 based on a motor torque command, the motor rotation speed, and the battery voltage. The motor torque command may be a command value from a host ECU (Electronic Control Unit). The motor rotation speed and the battery voltage may be sensor information. The battery voltage is the voltage of a high-voltage battery that supplies power to the motor 3. The method of calculating the motor loss based on these parameters is arbitrary, and a widely known method may be used.

[0036] The cooling ON / OFF determination unit 902 determines whether oil is being supplied to the stator coil 12 based on cooling oil temperature information (indicated as "cooling oil temperature" in FIG. 3). The cooling oil temperature may be a value based on sensor information. For example, when the cooling oil temperature is relatively low, the cooling ON / OFF determination unit 902 may determine that oil is not being supplied to the stator coil 12. Alternatively, the cooling ON / OFF determination unit 902 may determine whether oil is being supplied to the stator coil 12 based on operation information of an oil pump (not shown).

[0037] The coil temperature estimation unit 904 estimates the temperature of the stator coil 12 based on the loss calculation value from the motor loss calculation unit 900, the motor rotation speed, the determination result from the cooling ON / OFF determination unit 902, and sensor information from a coil temperature sensor (not shown) (denoted as "coil temperature sensor" in FIG. 3). The temperature of the stator coil 12 may vary depending on the position (location) of the stator coil 12. In this embodiment, the coil temperature estimation unit 904 estimates the temperature of the hottest location in the stator coil 12 (i.e., the maximum temperature of the stator coil 12 at that time). In this case, even if, for example, the coil temperature sensor cannot be placed in the hottest location in the stator coil 12 due to layout constraints or even if the influence of the time constant of the coil temperature sensor is relatively large, the maximum temperature of the stator coil 12 can be estimated with relatively high accuracy. Note that such estimation of the maximum temperature of the stator coil 12 is useful from the perspective of protecting the stator coil 12. Note that the coil temperature sensor may be in the form of, for example, a thermistor.

[0038] The coil temperature estimation unit 904 may change the constants of the equation for estimating the temperature of the stator coil 12 based on the determination result by the cooling ON / OFF determination unit 902. For example, the constants may be adapted so that the temperature of the stator coil 12 is estimated to be lower when oil is supplied to the stator coil 12 than when oil is not supplied to the stator coil 12. Alternatively, separate maps may be used for the state when oil is supplied to the stator coil 12 and the state when oil is not supplied to the stator coil 12.

[0039] The temperature of the stator coil 12 estimated by the coil temperature estimation unit 904 in this manner has a certain degree of accuracy as a base value for the temperature of the stator coil 12, but does not reflect the influence of heat received from the oil that becomes hot due to losses in the clutch WSC.

[0040] That is, as described above, although the oil flowing through the clutch WSC is returned to the oil pan (not shown), a portion of the oil takes a path that will apply to the second coil end 12Eb before reaching the oil pan. In this case, if the clutch WSC slips, such as when starting, the oil, which has become hot as a result of lubrication, will apply to the second coil end 12Eb. In this way, if some of the oil that has been supplied to the clutch WSC and heated up, applies to the second coil end 12Eb (see arrow R1 in FIG. 2), this will cause the temperature of the second coil end 12Eb to rise. In this way, in this embodiment, the second coil end 12Eb is positioned so that it will be exposed to the oil supplied to the clutch WSC, and therefore is prone to becoming hot due to the heat it receives from the oil that has been supplied to the clutch WSC and heated up.

[0041] Therefore, in this embodiment, the processing device 90 includes a correction temperature calculation unit 908 as a component for reflecting the influence of such heat reception in the calculated value of the temperature of the stator coil 12 .

[0042] The correction temperature calculation unit 908 derives the temperature rise of the stator coil 12 caused by the clutch loss as an additional value (correction value) based on the clutch loss input via the filter 906. The filter 906 is a filter for reducing noise in the input (clutch loss), and may be configured as, for example, a low-pass filter.

[0043] The clutch loss is a loss in the clutch WSC, and may be, for example, a slip loss in the clutch WSC. In this case, the slip loss may be calculated as: Slip Loss = Transmission Torque x Differential Rotation x 2π x 1 / 60. In this case, the transmission torque may be a value based on a command value, and is the combined value of both the motor 3 and the engine 2. The differential rotation is the difference in rotation speed between the rotor 20 and the input shaft 50a, and may be a value based on sensor information from the respective rotation angle sensors.

[0044] Here, the loss in the clutch WSC first causes the oil flowing through the clutch WSC to become hot. That is, the oil flowing through the clutch WSC becomes hot as it receives heat from the clutch WSC. Then, the stator coil 12 receives heat from the hot oil, causing the stator coil 12 to become hot. The temperature of the second coil end 12Eb, which increases due to the heat received from the hot oil (hereinafter also referred to as the "clutch heat reception temperature"), tends to increase as the clutch loss increases.

[0045] For this reason, in this embodiment, the correction temperature calculation unit 908 calculates the correction temperature in such a manner that the calculated temperature of the stator coil 12 increases as the clutch loss increases. Specifically, the correction temperature calculation unit 908 calculates the clutch heat reception temperature as the correction temperature using a map such as that shown in FIG. 4. In this case, the relationship between the clutch loss and the clutch heat reception temperature is defined in such a manner that the clutch heat reception temperature increases nonlinearly as the clutch loss increases. Note that the relationship between the clutch loss and the clutch heat reception temperature (correction temperature) may be adapted using testing, analysis, etc.

[0046] The corrected temperature calculated in this manner by the corrected temperature calculation unit 908 is added to the temperature of the stator coil 12 calculated by the coil temperature estimation unit 904 as described above, and output as the final temperature of the stator coil 12 (hereinafter also referred to as the "coil temperature estimation value for motor protection").

[0047] Incidentally, the loss in the clutch WSC includes slip loss and therefore is a relatively large value (for example, significantly larger than the loss in the clutch K0). For this reason, the clutch heat receiving temperature tends to be a relatively large value.

[0048] Therefore, if the temperature of the stator coil 12 calculated by the coil temperature estimation unit 904 as described above is output as the final temperature of the stator coil 12 (coil temperature estimation value for motor protection) without adding the correction temperature calculated by the correction temperature calculation unit 908, the error in the coil temperature estimation value for motor protection will be relatively large.

[0049] In this regard, according to this embodiment, as described above, it is possible to calculate a coil temperature estimate for motor protection that takes into account the clutch heat reception temperature by providing the correction temperature calculation unit 908. That is, according to this embodiment, the influence of heat received by the stator coil 12 (particularly the second coil end 12Eb) from oil that has become hot due to losses in the clutch WSC is taken into account as described above, and therefore the accuracy of the coil temperature estimate for motor protection (accuracy relative to the temperature at the actual hottest part of the stator coil 12) can be effectively improved.

[0050] The coil temperature estimate for motor protection represents the temperature at the hottest part of the stator coil 12 at that time (for example, the part at the second coil end 12Eb), and can therefore be effectively used to protect the motor 3. For example, if the coil temperature estimate for motor protection exceeds a threshold, the operation of the motor 3 can be restricted to appropriately prevent the temperature of the stator coil 12 from becoming excessively high. According to this embodiment, by improving the accuracy of the coil temperature estimate for motor protection, protection of the motor 3 can be started or ended at an appropriate stage depending on the temperature of the stator coil 12, and the motor 3 can be operated efficiently.

[0051] In this embodiment, the coil temperature estimation unit 904 performs calculation processing separately from the correction temperature calculation unit 908, and therefore can realize calculations that take into account differences in their respective time constants (for example, the time constant of the increase in the clutch heat reception temperature in response to an increase in clutch loss is significantly greater than the time constant of the increase in the temperature of the stator coil 12 in response to an increase in motor loss, etc.). However, the coil temperature estimation unit 904 may incorporate the function of the correction temperature calculation unit 908. That is, the coil temperature estimation unit 904 may derive a coil temperature estimate for motor protection based on the loss calculation value from the motor loss calculation unit 900, the motor rotation speed, the determination result by the cooling ON / OFF determination unit 902, sensor information from a coil temperature sensor (not shown), and the clutch loss.

[0052] Furthermore, the coil temperature estimation unit 904 may estimate the temperature of the stator coil 12 using machine learning results. For example, when using artificial intelligence, this can be achieved by implementing a convolutional neural network obtained by machine learning. In machine learning, for example, actual data related to various input information (motor loss, motor rotation speed, sensor information from a coil temperature sensor, clutch loss) may be used to learn weights of a convolutional neural network that minimizes the error (error from the actual temperature) of the coil temperature estimate value for motor protection.

[0053] Next, a modified example of the coil temperature calculation function will be described with reference to FIGS.

[0054] FIG. 5 is a block diagram showing an example of a processing device 90A that realizes the coil temperature calculation function according to the first modified example.

[0055] The processing device 90A shown in FIG. 5 differs from the processing device 90 shown in FIG. 3 in that the corrected temperature calculation unit 908 is replaced with a corrected temperature calculation unit 908A.

[0056] The correction temperature calculation unit 908A derives the increase in temperature of the stator coil 12 caused by the clutch loss as an additional value (correction value) based on the loss in the clutch WSC and the amount of oil supplied to the clutch WSC.

[0057] Here, the greater the amount of oil supplied to the clutch WSC, the greater the increase in temperature of the stator coil 12 due to clutch loss. This is because the greater the amount of oil supplied to the clutch WSC, the greater the likelihood that the oil will absorb heat due to clutch loss.

[0058] Therefore, in this modification, the correction temperature calculation unit 908A may calculate the correction temperature in such a manner that the greater the clutch loss, the higher the calculated value of the temperature of the stator coil 12, and the greater the amount of oil supplied to the clutch WSC, the higher the calculated value of the temperature of the stator coil 12. Note that the relationship between the amount of oil supplied to the clutch WSC, the clutch loss, and the clutch heat receiving temperature (correction temperature) may be adapted using testing, analysis, etc.

[0059] In this way, according to this embodiment, the coil temperature estimate for motor protection can be derived taking into account not only the clutch loss but also the amount of oil supplied to the clutch WSC, thereby making it possible to further improve the accuracy of the coil temperature estimate for motor protection.

[0060] FIG. 6 is a block diagram showing an example of a processing device 90B that realizes the coil temperature calculation function according to the second modified example.

[0061] The processing device 90B shown in FIG. 6 differs from the processing device 90 shown in FIG. 3 in that the corrected temperature calculation unit 908 is replaced with a corrected temperature calculation unit 908B.

[0062] The correction temperature calculation unit 908B derives the temperature rise of the stator coil 12 caused by the clutch loss as an addition value (correction value) based on the loss in the clutch WSC and the motor torque command. In the example shown in Fig. 6, the motor torque command is converted into an absolute value and input to the correction temperature calculation unit 908B.

[0063] Here, when the motor torque command becomes relatively large, the increase in temperature of the stator coil 12 due to the motor loss becomes significant, and the effect of the increase in temperature of the stator coil 12 due to the clutch loss may be reduced accordingly.

[0064] Therefore, in this modification, the correction temperature calculation unit 908B may calculate the correction temperature in such a manner that the larger the absolute value of the motor torque command is under the condition that the clutch loss is the same, the lower the correction temperature becomes. Note that the relationship between the absolute value of the motor torque command and the clutch loss and the clutch heat receiving temperature (correction temperature) may be adapted using testing, analysis, etc.

[0065] In this way, according to this embodiment, the coil temperature estimate for motor protection can be derived taking into account not only the clutch loss but also the magnitude of the motor torque command, thereby making it possible to further improve the accuracy of the coil temperature estimate for motor protection.

[0066] Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or a plurality of components of the above-described embodiments. Furthermore, among the effects of each embodiment, the effects related to the dependent claims are additional effects that are distinct from the generic concept (independent claim).

[0067] For example, in the above-described embodiment, the correction temperature calculation unit 908 calculates the correction temperature based on the loss in the clutch WSC, but the correction temperature may also be calculated taking into consideration losses in other mechanisms of the power transmission mechanism. For example, the correction temperature calculation unit 908 may calculate the sum of a first correction temperature calculated based on the loss in the clutch WSC and a second correction temperature calculated based on the loss in the clutch K0 as the correction temperature (the temperature to be added to the temperature of the stator coil 12 calculated by the coil temperature estimation unit 904). [Explanation of symbols]

[0068] 1··· Hybrid drive device (vehicle drive device), 3··· Motor (rotating electric machine), 6··· Case, WSC··· Clutch, 12··· Stator coil, 12Eb··· Coil end (axial end), 50··· Transmission mechanism, 90, 90A, 90B··· Processing device, 904··· Coil temperature estimation unit (base value calculation unit), 908, 908A, 908B··· Correction temperature calculation unit (addition value calculation unit)

Claims

1. Case and a power transmission mechanism disposed within the case and supplied with oil; a rotating electric machine having a stator coil disposed radially outside the power transmission mechanism in the case and positioned so as to be exposed to oil supplied to the power transmission mechanism; a coil temperature sensor; a processing device that calculates a temperature of the stator coil based on the coil temperature sensor, a loss in the rotating electric machine, and a loss in the power transmission mechanism, The stator coil receives heat from the oil in contact with the stator coil.

2. 2. The vehicle drive system according to claim 1, wherein the processing unit calculates the temperature of the stator coil in such a manner that the calculated value of the temperature of the stator coil increases as the loss in the power transmission mechanism increases.

3. The vehicle drive system according to claim 1 , wherein the processing unit calculates the temperature of the stator coil further based on a flow rate of oil supplied to the power transmission mechanism.

4. The processing device includes: a base value calculation unit that derives a base value of the temperature of the stator coil based on a loss in the rotating electric machine; 4. The vehicle drive device according to claim 1, further comprising: an additional value calculation unit that derives an additional value of the temperature of the stator coil based on losses in the power transmission mechanism, the additional value being added to the base value derived by the base value calculation unit.

5. The vehicle drive device according to claim 1 , wherein the power transmission mechanism includes a clutch provided between a speed change mechanism and the rotating electric machine.

6. 2. The vehicle drive system according to claim 1, wherein the loss in the power transmission mechanism includes a loss in a clutch.

7. 7. The vehicle drive device according to claim 5, wherein oil supplied to the power transmission mechanism is discharged through the clutch toward an axial end of the stator coil.

8. 2. The vehicle drive system according to claim 1, wherein the processing unit calculates the temperature of the stator coil in such a manner that the calculated value of the temperature of the stator coil increases nonlinearly as the loss in the power transmission mechanism increases.

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