JP2011114947A - Cooling apparatus for drive unit of right and left independent drive type vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce capacity and size of a cooler by leveling a cooling load. <P>SOLUTION: In a cooling apparatus for a drive unit of a right and left independent drive type vehicle having drive units DU1, DU2 capable of independently driving four wheels FL, FR, RL and RR on front and rear and right and left, the drive units include a first drive unit DU1 capable of independently driving the front left wheel FL and the rear right wheel RR respectively, and a second drive unit DU2 capable of independently driving the front right wheel FR and the rear left wheel RL respectively; and include a first cooler CS1 for dissipating heat from the first drive unit DU1 to cool the first drive unit DU1, and a second cooler CS2 for dissipating heat from the second drive unit DU2 to cool the second drive unit DU2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vehicle capable of independently driving front, rear, left and right wheels, and more particularly to an apparatus for cooling a drive unit of these wheels.

  With the improvement in performance of motors and power storage devices, motors are being used as driving force sources for vehicles. As an example, a so-called in-wheel motor vehicle is known in which a motor is arranged for each of the front, rear, left and right wheels, and these wheels can be driven individually. In general, motors provided for each wheel in this type of vehicle generally have the same specifications, and the invention described in Patent Document 1 provides controllability, vehicle safety, or fail-safety. For the purpose of establishment, etc., two power systems are provided by connecting the motors of the wheels whose front and rear and left and right sides are opposite to each other by a power bus, a power storage device is provided for each power system, and DC / The two power systems are connected by a power switching supply means such as a DC converter or a relay.

  Patent Document 2 describes a control device for an electric vehicle. The device described in Patent Document 2 is intended to reduce the size and cost of the configuration, and includes four electric motors. Two inverters are provided, and one inverter unit and a cooling unit are provided for the two electric motors. An apparatus for cooling this type of motor is described in Patent Document 3, and in the vehicle described in Patent Document 3, an oil pump is built in the in-wheel motor for each wheel, and the oil pump is used to add the oil pump. The compressed oil is supplied to the motor for cooling. Patent Document 4 describes a device configured to cool not only a motor but also an inverter with a coolant.

JP 2001-333508 A JP 2009-72049 A JP 2008-195233 A JP 2008-256313 A

  It is desired that each wheel of the vehicle has a complex lateral force as well as a longitudinal force when accelerating, decelerating, or turning left and right, and generating a torque suitable for the situation. In that respect, the device described in Patent Document 1 has a controllability improved by connecting wheel motors which are opposite to each other in the front and rear and left and right directions, and a torque suitable for the situation. Can control. However, since the load of each motor is not the same and there is a bias, when cooling the entire motor in response to a motor with a large load, the cooling device becomes large or the cooling efficiency is impaired. There is a risk.

  Moreover, in the apparatus described in Patent Document 2, since not only the inverter unit but also the cooling unit is provided for every two of the four motors, finer cooling control for the motors becomes possible. However, since two of the four electric motors are simply combined, it is not sufficient to perform cooling control that accurately reflects the torque or load of the electric motor according to the running state of the vehicle. There is still room for improvement in terms of improving energy efficiency.

  The present invention has been made paying attention to the above technical problem, and aims to reduce the size of the cooling device without impairing the cooling performance of the drive unit that independently drives the left and right wheels. is there.

  In order to achieve the above object, the invention of claim 1 is directed to a drive unit cooling apparatus for a left and right independent drive vehicle including a drive unit capable of independently driving each of the front, rear, left and right four wheels. The drive unit includes a first drive unit capable of independently driving the left front wheel and the right rear wheel, and a second drive unit capable of independently driving the right front wheel and the left rear wheel. A first cooler configured to take heat from the first drive unit and cool the first drive unit; and a second cooler to take heat from the second drive unit and cool the second drive unit. It is characterized by that.

  According to a second aspect of the present invention, in the first aspect of the invention, each of the drive units includes a motor provided for each wheel and a controller that controls a current or a voltage of the motor. When an abnormality occurs in one side and cooling by the one cooler cannot be performed, the load of the motor driven by the other drive unit is stopped while stopping one drive unit cooled by the one cooler, A drive unit cooling device for a left and right independent drive vehicle, wherein the drive unit is configured to increase in accordance with the disappearance of a load of a motor driven by the one drive unit by stopping one drive unit. is there.

  According to a third aspect of the invention, in the second aspect of the invention, the controller includes an inverter capable of changing a load factor, and the motor controlled by the inverter when the load factor of the inverter in any one of the drive units is changed. When the torque of the vehicle is changed, the torque distribution ratio for the motor controlled by the inverter whose load factor is changed is controlled so that the traveling direction of the vehicle before the load factor is changed is maintained. A drive unit cooling device for a left and right independent drive vehicle, characterized in that the drive unit is cooled.

  According to the first aspect of the present invention, the two wheels driven by each drive unit are wheels having a relationship in which the magnitudes of loads are opposite to each other when the vehicle turns or accelerates / decelerates. If the load by controlling the wheel is large, the load by controlling the other wheel is small. Since the relationship between the magnitudes of the loads is the same for all the drive units, the heat generation of the drive units is leveled, and therefore the cooling capacity required for each cooler is also leveled. There is no need to increase the capacity or the size of the cooler in particular, and the overall configuration of the apparatus can be reduced without impairing the cooling performance.

  Further, in the invention of claim 2, when a situation in which cooling by any one of the coolers cannot be performed occurs, the drive unit to be cooled by the cooler stops, and either the left or right wheel and either the left or right Although the rear wheel loses driving force, the lost amount is compensated by the other driving unit and wheels, so that the running stability is not impaired, and at the same time, the other driving unit is cooled by the corresponding cooler. Therefore, it is avoided or suppressed that the obstacle of driving | running | working of a vehicle also arises at the point.

  According to the invention of claim 3, when the torque distribution of any two motors is changed by changing the load factor of any of the inverters or the like, the changed load factor is maintained. However, since the torque distribution is changed so as to maintain the traveling direction of the vehicle, it is possible to avoid the generation of heat exceeding the cooling capacity of each drive unit and to maintain the behavior or stability of the vehicle.

It is a block diagram which shows typically a specific example of this invention. It is a graph which shows collectively the magnitude relationship of the load of each motor about the time of acceleration, deceleration, left turn, and right turn. It is a block diagram which shows typically another specific example of this invention. It is a block diagram which shows the torque distribution ratio when it becomes impossible to cool with a 2nd cooler. It is a block diagram which shows the torque distribution ratio when it becomes impossible to drive the motor of a right front wheel. It is a block diagram which shows the torque distribution ratio when the load factor of a 2nd controller is reduced by half, Comprising: (a) at the time of straight power running, (b) at the time of straight regenerative braking, (c) at the time of right turn Is shown. It is a block diagram which shows the example which used the oil pump as a cooler.

  Next, the present invention will be described more specifically. The left and right independent drive vehicles that are the subject of the present invention are vehicles that can independently control the driving force and braking force at the respective wheels such as the left and right front wheels and the rear wheels, and a driving force source corresponding to these wheels. A typical example is a vehicle provided. The vehicle may not be a four-wheeled vehicle, and may have four or more wheels. In this case, at least the four wheels on the front, rear, left, and right are individually and independently driven. Just do it. The driving force source may be a power device that generates torque by some energy, and a motor is the most common because of demands for controllability and in-vehicle performance. In the case of using a motor as a driving force source for each wheel, it is essential that a motor is provided for each of the front, rear, left and right wheels and that each motor drives one wheel. Therefore, the position where the motor is provided and the transmission mechanism between the motor and the wheel may be variously configured as necessary.

  A so-called in-wheel motor so-called left and right independent drive type is a drive type in which a traction motor is incorporated in a wheel to which a tire is attached, and is an example of a vehicle to which the present invention can be applied. This is schematically shown in FIG. 1, and includes front, rear, left and right four wheels FL, FR, RL, RR, and a traction motor for traveling on each of these wheels FL, FR, RL, RR. MFL, MFR, MRL, and MRR (hereinafter simply referred to as a motor) are provided. These motors MFL, MFR, MRL, and MRR generate torque and function as a so-called motor that rotates the wheels FL, FR, FL, and RR, and are forcibly rotated by the traveling inertia force of the vehicle to generate electric power. What has the function as the generator to generate | occur | produce is preferable. Therefore, as the motors MFL, MFR, MRL, and MRR, permanent magnet type AC synchronous motors can be employed.

  In the example shown in FIG. 1, these wheels FL, FR, FL, RR and motors MFL, MFR, MRL, MRR are divided into two sets. Specifically, the left front wheel FL and its motor MFL and right rear The wheel RR and its motor MRR are one set, and the right front wheel FR and its motor MFR, the left rear wheel RL and its motor MRL are one set. A pair of wheels and motors located on a so-called diagonal line constitute one set. Here, the “set” means that the controller and the cooler are shared, and therefore the controllers INV1 and INV2 are provided for each of the above-described sets. That is, the first controller INV1 controls the motor MFL of the left front wheel FL and the motor MRR of the right rear wheel RR, and the second controller INV2 controls the motor MFR of the right front wheel FR and the motor MRL of the left rear wheel RL. Is configured to do.

  These controllers INV1 and INV2 are electrically connected to a power storage device BAT such as a battery. Therefore, each controller INV1, INV2 drives each motor MFL, MFR, MRL, MRR using the electric power of power storage device BAT, and the power generated by each motor MFL, MFR, MRL, MRR is supplied to power storage device BAT. It is comprised so that control which charges may be performed. When each motor MFL, MFR, MRL, MRR is constituted by a permanent magnet type AC synchronous motor as described above, each controller INV1, INV2 is constituted mainly by an inverter.

  The first controller INV1 and the motor MFL of the left front wheel FL and the motor MRR of the right rear wheel RR controlled thereby constitute the first drive unit DU1, and are also controlled by the second controller INV2 and the same. The motor MFR for the right front wheel FR and the motor MRL for the left rear wheel RL constitute a second drive unit DU2. The drive units DU1 and DU2 are cooled so that the operations of the motors MFL, MFR, MRL, and MRR are not limited by temperature. Specifically, a first cooler CS1 for cooling the first drive unit DU1 and a second cooler CS2 for cooling the second drive unit DU2 are provided. In other words, a pair of motors and their controllers located on opposite sides in the front-rear direction and the left-right direction are combined into one set, and coolers CS1 and CS2 are provided for each set, and cooling is performed for each set. ing.

  These coolers CS1 and CS2 are configured to cool the drive units DU1 and DU2 by taking heat from the controllers (inverters) INV1 and INV2 and / or the motors MFL, MFR, MRL and MRR and releasing them to the outside. For example, a forced air-cooled cooler that blows cooling air, a cooler that takes heat away with lubricating oil or an appropriate coolant, and the like can be employed. FIG. 1 shows coolers CS1 and CS2 configured to take heat with a lubricating oil or an appropriate coolant and release the heat to the outside air by heat exchangers (radiators) Rd1 and Rd2. That is, the heat of the motor MFL of the left front wheel FL and the motor MRR of the right rear wheel RR and the heat of the controller INV1 controlling these motors MFL and MRR are released from the first cooler CS1 to the atmosphere, and the right front wheel FR. The drive units DU1 and DU2 are cooled by releasing the heat of the motor MFR of the motor MFR and the motor MRL of the left rear wheel RL and the heat of the controller INV2 controlling these motors MFR and MRL from the second cooler CS2 to the atmosphere. Is configured to do.

  In the vehicle configured as described above, each motor MFL, MFR, MRL, MRR travels by outputting torque, and during deceleration, each motor MFL, MFR, MRL, MRR functions as a generator for power generation. The accompanying reaction force torque is caused to function as a braking force, and during turning, the output torque of the motor on the outer ring side is set to be relatively large with respect to the output torque of the motor on the inner ring side to assist turning. In any of these cases, current flows through the coils of the motors MFL, MFR, MRL, and MRR, so heat is inevitably generated, and heat is generated by stirring or shearing of the lubricating oil. Further, the controllers INV1 and INV2 Heat is generated with the general control. The amount of generated heat is an amount corresponding to the load (or load factor) of each motor MFL, MFR, MRL, MRR or controllers INV1, INV2. Then, the heat is dissipated into the atmosphere by the coolers CS1 and CS2, and the drive units DU1 and DU2 are cooled so as not to exceed a predetermined temperature.

  Each of the coolers CS1 and CS2 cools by taking away heat generated by two motors MFL and MRR (or MFR and MRL) located on a so-called diagonal line or by controlling the heat generated by the controller INV1 (or INV2). However, if one of the two motors MFL, MRR (or MFR, MRL) targeted by each cooler CS1, CS2 is large, the other load is small, so each cooler CS1, CS2 only needs to have a cooling capacity corresponding to a load that is twice or close to the average value of the load of these two motors. When cooling the front two-wheel or rear two-wheel motor with a single cooler. In comparison, the cooler can be reduced in capacity or size.

  Specifically, FIG. 2 is a chart collectively showing the relative magnitudes of the loads of the motors MFL, MFR, MRL, and MRR during acceleration / deceleration and turning, and during acceleration, the rear wheels RL and RR The driving torque is made relatively larger than the driving torque of the front wheels FL and FR. Therefore, of the two motors in the first drive unit DU1 and the second drive unit DU2, the drive torque or load of one motor is large and the drive torque load of the other motor is small. At the time of deceleration, contrary to acceleration, the braking torque at the front wheels FL and FR is made relatively larger than the braking torque at the rear wheels RL and RR. Since one motor in each of the drive units DU1 and DU2 is a front wheel side motor and the other motor is a rear wheel side motor, the first drive unit DU1 and the second drive unit DU2 are the same as in acceleration. Of these two motors, the driving torque or load of one motor is large and the driving torque or load of the other motor is small.

  At the time of turning, the driving torque of the outer ring is relatively increased with respect to the driving torque of the inner ring. On the other hand, one motor in each driving unit DU1, DU2 is a motor on the inner ring side, and the other motor. Is a motor on the outer ring side, so that the driving torque or load of one of the two motors in the first drive unit DU1 and the second drive unit DU2 is large, as in acceleration and deceleration. And the driving torque or load of the other motor is reduced.

  Thus, in the configuration according to the present invention, when the load on one of the two motors targeted by each of the coolers CS1 and CS2 is large, the load on the other motor becomes relatively small. The coolers CS1 and CS2 having the cooling capacity corresponding to the load of the doubled value may be used, and the coolers CS1 and CS2 can be downsized.

  In the drive unit cooling device according to the present invention, the drive unit of the left front wheel FL and the right rear wheel RR is cooled by one cooler, and the drive unit of the right front wheel FR and the left rear wheel RL is replaced by another one. It is only necessary to be configured to cool with a cooler. Therefore, a controller is provided for each motor MFL, MFR, MRL, MRR as well as a vehicle configured to control two motors with one controller. The motors MFL, MFR, MRL, MRR and the controller may be divided into two sets as described above, and a cooler may be provided for each set. An example thereof is shown in FIG. 3, where the first controller INV1 is configured to control the motor MFL of the left front wheel FL, and the second controller INV2 is configured to control the motor MFR of the right front wheel FR. In addition, a third controller INV3 for controlling the motor MRL for the left rear wheel RL and a fourth controller INV4 for controlling the motor MRR for the right rear wheel RR are provided. The first cooler CS1 is configured to cool the motors MFL and MRR of the left front wheel FL and the right rear wheel RR and / or the controllers INV1 and INV4, and the second cooler CS2 includes the right front wheel FR and The motors MFR and MRL and / or the controllers INV2 and INV3 with the left rear wheel RL are configured to be cooled.

  Even in such a case, the two motors in the drive units DU1 and DU2 targeted by the respective coolers CS1 and CS2 have a relationship in which the other load decreases when one load is large. Thus, similarly to the specific example described above, the cooling loads of the respective coolers CS1 and CS2 are leveled, and the size can be reduced.

  By the way, when one of the above-described coolers CS1 and CS2 cannot be cooled due to a failure or the like, any two motors MFL and MRR (or MFR) that have received cooling in the coolers CS1 and CS2 in which the abnormality has occurred. , MRL) cannot be driven. In that case, the control may be performed as follows. FIG. 4 shows a state in which the second drive unit DU2 cannot be cooled due to an abnormality in the second cooler CS2, and the second controller INV2 is coupled with the fact that the second controller INV2 itself is not cooled. Control of the motor MFR and the motor MRL of the left rear wheel RL is stopped, and the driving torque or braking torque of these wheels FR and RL is set to “0”. Note that the numbers shown in brackets in FIG. 4 indicate the relative load ratio or torque distribution ratio. Therefore, “0” for the second controller INV2 indicates that the second controller INV2 is stopped.

  On the other hand, the motor MFL of the left front wheel FL and the motor MRR of the right rear wheel RR are controlled so as to handle the driving torque or the braking torque by “1” respectively. This control is such that the left front wheel FL is also responsible for the lost torque of the left rear wheel RL, and the right rear wheel RR is also responsible for the lost torque of the right front wheel FR, and therefore the first controller INV1. The load of “2” is “2”. Since the first cooler CS1 for cooling the first drive unit DU1 including the controller INV1 is functioning normally, the left front wheel FL and the right rear wheel RR generate the same drive torque during straight running, The same braking torque is generated during braking, and the behavior of the vehicle becomes stable. That is, the stability and driving performance or braking performance of the vehicle can be maintained even if either one of the coolers CS1 and CS2 fails.

  On the other hand, when a situation occurs in which drive torque and braking torque cannot be generated, such as when one of the motors fails, control of the other motor paired on the left and right with respect to the failed motor is stopped, and The torque lost by stopping the motor is handled by another motor that can function normally. FIG. 5 shows an example in which a failure occurs in the motor MFR of the right front wheel FR, and because the driving torque or braking torque cannot be generated in the right front wheel FR, it is paired with the right front wheel FR in the left-right direction. The motor MFL of the left front wheel FL is stopped so that driving torque and braking torque are not generated even in the left front wheel FL. That is, the loads on the front wheels FL and FR are controlled to “0”.

  The loads (torque distribution ratios) of the motors MRR and MRL of the rear wheels RR and RL are set to “1” so that the loads on the front wheels FL and FR that will disappear in this way are handled by the left and right rear wheels RL and RR. To control. Therefore, since the load in each drive unit DU1, DU2 is “1”, the cooling load in each cooler CS1, CS2 is “1”, which is the same as before the occurrence of a failure in the motor. That is, with the configuration according to the present invention, even if a failure occurs in any one of the motors, the load on the coolers CS1 and CS2 does not increase particularly. Therefore, the coolers CS1 and CS2 are downsized. can do. At the same time, the stability of the vehicle can be maintained.

  As described above, in the cooling device according to the present invention, cooling is performed for each of the drive units DU1 and DU2, but the temperature of any of the drive units DU1 and DU2 may rise due to some factor. In that case, heat generation is suppressed by changing the limit value of the load factor of the controllers (inverters) INV1 and INV2 in the drive units DU1 and DU2 whose temperature has risen. Since the torques of the motors MFL, MFR, MRL, and MRR controlled by the controllers INV1 and INV2 change as the load factor limit value is changed, in the present invention, the motors MFL and MFR whose torques are limited. , MRL, and MRR, the torque distribution ratio is changed so as to maintain the behavior of the vehicle (particularly the traveling direction) without simply changing the torque distribution ratio according to the change in the load factor limit value.

  Examples thereof are shown in FIGS. 6A, 6B and 6C. The example shown in FIG. 6A shows an example in which the load factor limit value of the controller INV2 in the second drive unit DU2 is reduced by half when the vehicle is powering in a straight traveling state. In FIG. 6, the numerical values indicated with brackets for the controllers INV1 and INV2 indicate the load factor (1 = 100%), and the brackets for the motors MFL, MFR, MRL, and MRR. The numerical value attached and described indicates the torque distribution ratio. In a normal state where the load factor is not particularly limited, the load factor of each controller (inverter) INV1 and INV2 is “1”. Each of the torque distribution ratios is “0.5”. From this state, when the load factor of the second controller INV2 is limited (the load factor limit value becomes large) and the load factor becomes “0.5”, the torque of each motor MFR, MRL in the second drive unit DU2 The distribution ratio is halved in the same manner as the change rate of the load factor, and becomes “0.25”.

  In this state, the sum of the torque distribution ratios of the motors MFL and MRL on the left side of the vehicle is “0.75”. Similarly, the sum of the torque distribution ratios of the motors MFR and MRR on the right side of the vehicle is “0. 75 ", the left and right torques of the vehicle are equal and the straight traveling state can be maintained. In other words, since the moment for turning the vehicle does not occur, the previous driving state (traveling direction) can be maintained while maintaining the load factor and suppressing heat generation.

  When powering in the straight direction as described above, the torque distribution ratio for the motors MFL, MFR, MRL, and MRR may be changed to be equal to the rate of change of the load factor. When the vehicle is turning or turning, the torque distribution ratio is changed so as to maintain the previous driving state (traveling direction) without simply changing the torque distribution ratio according to the change rate of the load factor. Specifically, FIG. 6 (b) shows the second controller INV2 in a state where the torque distribution ratio at the front wheels FL and FR is relatively large ("0.7") and regenerative braking is performed. In this example, the load factor is limited (the load factor limit value increases) and the load factor becomes “0.5”. In this case, if the torque distribution ratio of the motors MFR and MRL in the second drive unit DU2 is changed according to the change rate of the load factor, the torque distribution ratio of the right front wheel FR at the motor MFR is halved to “0.35”. In addition, the torque distribution ratio of the left rear wheel RL in the motor MRL is halved to “0.15”. However, if this is done, the total torque distribution ratio on the left side of the vehicle will be “0.85”, whereas the total torque distribution ratio on the right side will be “0.65”. It may change. Therefore, in the present invention, the torque distribution ratios of the motor MFR of the right front wheel FR and the motor MRL of the left rear wheel RL are not halved, and the sum of the torque distribution ratios on the left and right sides of the vehicle is equalized. The torque distribution ratio of the motor MFR of the right front wheel FR and the motor MRL of the left rear wheel RL is changed. In the example shown in FIG. 6B, the torque distribution ratio of the motor MFR of the right front wheel FR is changed to “0.45”, and the torque distribution ratio of the motor MRL of the left rear wheel RL is “0.05”. Change to

  By doing this, the sum of the torque distribution ratios of the motors MFL and MRL on the left side of the vehicle becomes “0.75”, and similarly, the sum of the torque distribution ratios of the motors MFR and MRR on the right side of the vehicle is also “0”. .75 ", the left and right torques of the vehicle are equal and the straight traveling state can be maintained. In addition, the torque distribution ratio of the motors MFL, MFR on the front wheels FL, FR side becomes larger than the torque distribution ratio of the motors MRL, MRR of the rear wheels RL, RR, and desired energy regeneration can be performed. In other words, since the moment for turning the vehicle does not occur, it is possible to maintain the conventional traveling state (traveling direction and regenerative state) while maintaining the load factor and suppressing heat generation.

  Next, the control during turning will be described. FIG. 6C shows a case where the load factor is limited when turning right, and the motors MFL and MRL of the left wheels FL and RL of the vehicle. The load ratio of the controller INV2 in the second drive unit DU2 is set with the torque distribution ratio of the right wheel RL and RR set to “0.3” and the right wheel RL and RR respectively set to “0.3”. This is an example of a case where a restriction of halving occurs. That is, the difference between the torque distribution ratio on the left side and the torque distribution ratio on the right side is “0.8”. In this state, the torque distribution ratio of the motor MFR of the right front wheel FR is set according to the load factor limit value of the controller INV2. The torque distribution ratio is “0.15”, and similarly, the torque distribution ratio of the motor MRL of the left rear wheel RL is “0.35”. However, when this is done, the total torque ratio on the left side is “1.05”, whereas the total torque ratio on the right side is “0.45”, and the difference is “0.6”. . That is, “0.2” is reduced from the immediately preceding traveling state. If the moment to turn the vehicle in the right direction is proportional to the difference in torque between the left and right sides of the vehicle, the turning performance may decrease and the driving direction may change, or the turning state will be maintained. In order to do so, it is necessary to perform steering.

  In the present invention, in order to avoid such an inconvenience, the torque distribution ratios on the left and right sides of the vehicle are not simply halved, but the torque distribution ratios of the motor MFR of the right front wheel FR and the motor MRL of the left rear wheel RL are simply halved. The torque distribution ratio of the motor MFR of the right front wheel FR and the motor MRL of the left rear wheel RL is changed so that the total difference between the two becomes equal to the difference in the previous running state. In the example shown in FIG. 6C, the torque distribution ratio of the motor MFR of the right front wheel FR is changed to “0.05”, and the torque distribution ratio of the motor MRL of the left rear wheel RL is “0.45”. Change to

  By doing this, the sum of the torque distribution ratios of the motors MFL and MRL on the left side of the vehicle is “1.15”, and the sum of the torque distribution ratios of the motors MFR and MRR on the right side of the vehicle is “0.35”. The difference is “0.8” as before. That is, since the same moment as before the load factor is restricted can be applied to the vehicle, the conventional turning state or traveling direction can be maintained. In other words, it is possible to maintain the previous traveling state (traveling direction or turning state) while maintaining the load factor and suppressing heat generation.

  In each of the specific examples described above, an example using a cooler configured to dissipate heat into the atmosphere by means of heat exchangers (radiators) Rd1 and Rd2 has been described. Any structure may be used as long as it is provided for each drive unit including a motor arranged on a diagonal line and can be cooled for each drive unit, and is not limited to the structure shown in the above-described specific example. For example, as shown in FIG. 7, a first oil pump OP1 that supplies cooling oil to the motor MFL of the left front wheel FL and the motor MRR of the right rear wheel RR by circulating, and the motor MFR of the right front wheel FR and the left rear Each of the coolers may be configured by a second oil pump OP2 that circulates and supplies cooling oil to the motor MRL of the wheel RL.

  FL, FR, RL, RR ... wheels, MFL, MFR, MRL, MRR ... traction motor (motor), INV1, INV2, INV3, INV4 ... controller (inverter), BAT ... power storage device, DU1 ... first drive unit, DU2 ... second drive unit, CS1 ... first cooler, CS2 ... second cooler, Rd1, Rd2 ... heat exchanger (radiator), OP1 ... first oil pump, OP2 ... second oil pump.

Claims (3)

In a drive unit cooling device for a left and right independent drive vehicle provided with a drive unit that can drive each of the front, rear, left and right wheels independently of each other,
The drive unit includes a first drive unit capable of independently driving the left front wheel and the right rear wheel, and a second drive unit capable of independently driving the right front wheel and the left rear wheel. Consisting of
A first cooler for removing heat from the first drive unit and cooling the first drive unit;
A drive unit cooling device for a left and right independent drive vehicle, comprising: a second cooler for removing heat from the second drive unit and cooling the second drive unit. Each drive unit includes a motor provided for each wheel, and a controller for controlling the current or voltage of the motor,
When any one of the coolers is abnormal and cannot be cooled by the one cooler, the one drive unit cooled by the one cooler is stopped and driven by the other drive unit. The load of the motor is configured to increase in accordance with the disappearance of the load of the motor driven by the one drive unit by stopping the one drive unit. The drive unit cooling apparatus of the left-right independent drive vehicle of description. The controller includes an inverter whose load factor is changed,
When the load factor of the inverter in any one of the drive units is changed to change the torque of the motor controlled by the inverter, so as to maintain the traveling direction of the vehicle before the load factor is changed, The drive unit cooling apparatus for a left and right independent drive vehicle according to claim 2, wherein a torque distribution ratio to a motor controlled by an inverter whose load factor is changed is controlled.

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