JP5326415B2 - Motor cooling device - Google Patents

Description

  The present invention relates to a motor, and more particularly to a motor cooling device in which a magnetic force is reduced by an increase in temperature.

  The motor generates torque in the rotor by electromagnetic action between the stator and the rotor. As an example, there is known a motor configured to attach a permanent magnet to a rotor and generate a rotating magnetic field in a stator disposed on the outer periphery thereof.

  On the other hand, it is known that the magnetic force relatively decreases as the temperature of the coil or permanent magnet increases. Heat is also generated due to Joule loss in the coil and the rotor crossing the magnetic field. Conventionally, temperature rise due to this type of heat is suppressed. For example, Patent Document 1 describes that heat generated by an in-wheel motor is used to generate power by a thermoelectric element, and heat generated by energy loss is recovered as electric power.

JP-A-6-144021

  In the apparatus of Patent Document 1, a thermoelectric element is arranged on the outer surface of the casing of the in-wheel motor, and an electric fan is provided on the opposite side of the in-wheel motor with the thermoelectric element interposed therebetween, so A temperature difference is given, and it is comprised so that electric power generation may be performed by this. That is, the apparatus of Patent Document 1 is configured to generate heat by removing heat from the casing of the in-wheel motor. Therefore, in order to recover energy with the thermoelectric element, the temperature of the entire in-wheel motor needs to be raised to some extent. In other words, a sufficient temperature difference between the front and back surfaces of the thermoelectric element does not occur unless the temperature of the stator, rotor, or the like is significantly increased. As a result, there is a possibility that the magnetic force of the stator, the rotor or the like is reduced, or the power performance as a vehicle is reduced.

  The present invention has been made paying attention to the above technical problem, and an object of the present invention is to provide a motor cooling device capable of improving the power performance of a vehicle by avoiding thermal influence on output torque. To do.

In order to achieve the above object, a first aspect of the present invention is a motor cooling apparatus in which a stator that generates torque by electromagnetic action between the rotor and the rotor attached to the rotor shaft is disposed. A thermoelectric element is provided between the rotor shaft and the rotor, and when the thermoelectric element is energized, the rotor shaft side becomes a heat generating part and the rotor side becomes a heat absorbing part. A cooling mechanism for removing heat from the shaft is provided , and the rotor shaft or the rotor is attached with a power generating coil that generates electromotive force by relative rotation with the stator, and the power generated by the power generating coil is those characterized that you have been configured to be supplied to the thermoelectric element.

According to a second aspect of the present invention, in the first aspect of the present invention, the rotor includes a permanent magnet, the stator includes a coil that generates a rotating magnetic field, and the power generation coil is disposed between the rotor shaft or the rotor. Is provided with a transmission mechanism for transmitting torque from the rotor shaft or the rotor to the power generating coil and for making the rotational speed of the power generating coil different from the rotational speed of the rotor. is there.

According to a third aspect of the present invention, in the second aspect of the invention, the transmission mechanism includes three rotational elements that rotate differentially with each other, and any one rotational element is connected to the rotor shaft or the rotor. One rotating element is connected to the power generating coil, and another one rotating element is constituted by a differential rotating mechanism that is a reaction force element.

The invention of claim 4 is characterized in that in the invention of claim 3, a brake mechanism for selectively stopping the rotation of the rotating element is further provided.

According to a fifth aspect of the present invention, in the fourth aspect of the invention, the temperature determining means for determining that the temperature of the motor is equal to or higher than a predetermined threshold value, and the determining means that the temperature of the motor is equal to or higher than the threshold value. And a brake control means for stopping the rotation of the reaction force element by the brake mechanism when judged by.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the threshold value is a temperature that is predetermined as a temperature at which the magnetic force of the rotor decreases.

The invention of claim 7 is the invention according to any one of claims 1 to 6 , wherein the cooling mechanism includes a cooling passage through which the heat transport medium for cooling passes through the rotor shaft. It is.

According to the first aspect of the present invention, the heat generated in the rotor can be taken away by the heat absorption part of the thermoelectric element, and the magnetic force of the rotor can be prevented or suppressed from decreasing due to the increase in the temperature of the rotor. Further, the heat generated by the thermoelectric element can be taken away from the rotor shaft by the cooling mechanism . Moreover, since the power generation coil is provided on the rotor shaft or the rotor, it is possible to generate electricity with the rotation of the rotor. Moreover, since it is not necessary to introduce the electric power supplied to a thermoelectric element from the outside, an external power supply is not required.

According to the invention of claim 2, in addition to the effect similar to the effect of the invention of claim 1, since the rotation speed of the power generation coil is not synchronized with the rotation speed of the rotor shaft or the rotor, A difference in rotational speed is generated between the two so that electricity can be generated.

According to the invention of claim 3, in addition to the same effect as that of the invention of claim 2, an electromotive force according to the combination of the three rotating elements can be obtained.

According to the invention of claim 4, in addition to the effect similar to the effect of the invention of claim 3 , for example, when the cooling of the rotor is not necessary, the power generation amount can be suppressed by making the brake mechanism free. Therefore, the drag loss of the motor caused by rotating the power generation coil can be reduced or suppressed.

According to the invention of claim 5, in addition to the effect similar to the effect of the invention of claim 4, the brake mechanism for regulating the rotation of the reaction force element controls the engagement or release of the brake according to the temperature of the motor. Since it is comprised so that electric power generation according to the calorie | heat amount can be performed. Further, the rotor can be appropriately cooled by the generated electric power.

According to the invention of claim 6, in addition to the same effect as that of the invention of claim 5, since the demagnetization temperature at which the magnetic force of the rotor is reduced is set as a threshold value, it is possible to perform control not exceeding the demagnetization temperature. It is possible to avoid the influence of heat on the output torque of the motor.

According to the invention of claim 7, in addition to the effect similar to the effect of any one of the first to sixth inventions, the heat quantity of the heat generating portion of the thermoelectric element is deprived by the cooling heat transport medium flowing through the cooling passage. Therefore, the stagnation of heat in the rotor or rotor shaft is suppressed or prevented. Moreover, since the heat which demagnetizes the magnetic force of a rotor can be moved, the cooling performance of a rotor improves.

Next, the present invention will be described more specifically. FIG. 1 schematically shows a reference example of a cooling device for a motor 1 according to the present invention. An example of the motor 1 according to the present invention is to provide a torque to the rotor 4 by generating a magnetic field by energizing the rotor 4 provided in the rotor shaft 2 and having the permanent magnet 3 disposed therein and the coil 5. This is a so-called permanent magnet type synchronous motor 1 composed of a stator 6. Although not shown, a motor 1 according to the present invention detects the motor temperature T _m sensors and required torque T _rq or current value A _M detects the temperature, includes an ECU for processing, so as to be electrically controlled It has become.

A thermoelectric element 10 according to the present invention is disposed between the rotor 4 and the rotor shaft 2. In addition, as a cooling mechanism in the present invention, a cooling passage 7 is formed through the rotor shaft 2 to circulate the cooling heat transport medium. Here the thermoelectric element 10 is a Peltier device 10 that is configured to produce a heat absorbing portion 8 and the heating portion 9 by being energized, the heat absorbing unit 8 the rotor 4 side, originating the heat unit 9 is cooling passage 7 side It is arranged to be. For example, a battery may be used as the power source 11 for energizing the Peltier element 10. The cooling heat transport medium may be oil for lubricating or cooling the motor 1, for example. In the example shown here, oil was used as the cooling heat transport medium. This oil is configured to forcibly flow through the cooling passage 7 by the oil pump 12. Oil is generally used in the past, and has a characteristic that the viscosity changes depending on the temperature and the viscosity increases as the temperature decreases.

  According to the cooling device configured as described above, the rotor 4 is cooled as follows. First, a current is supplied from the power supply 11 to the Peltier element 10 described above. In that case, the direction of the current is set so that the portion of the Peltier element 10 on the rotor 4 side becomes the heat absorbing portion 8 and the opposite rotor shaft 2 side becomes the heat generating portion 9. When heat is generated in the rotor 4 by driving the motor 1, the heat is transmitted to the heat absorbing portion 8 in the Peltier element 10 that is energized as described above, and further, a cooling passage disposed in contact with the heat generating portion 9. Heat is transferred to the oil that flows through 7. Therefore, since the heat generated in the rotor 4 is actively taken away, demagnetization of the permanent magnet 3 disposed in the rotor 4 can be prevented or suppressed. As a result, the performance degradation of the motor 1 due to heat can be prevented or suppressed.

FIG. 2 schematically shows an example of the cooling device for the motor 1 according to the present invention. A power generation coil 17 is disposed so as to cross the rotating magnetic field generated in the stator 6 as the power source 11 of the Peltier element 10. Further, by using a transmission mechanism having a differential action, a rotational speed difference ΔN _r is generated between the rotor 4 and the power generation coil 17 so that power is generated from the rotating magnetic field generated in the stator 6 and the power generation coil. It is configured. The transmission mechanism is a single pinion type differential rotation mechanism 13 composed of three rotation elements. In FIG. 2, the sun gear 14 is connected to the rotor shaft 2 as an input element, the ring gear 16 is a reaction force element, and the carrier 15 is connected to a power generation coil 17 as an output element. The power generating coil 17 is composed of a cage rotor 17 around which a coil is wound. Electric power generated from the cage rotor 17 and the rotating magnetic field generated in the stator 6 is configured to be supplied to the Peltier element 10 via the slip ring 18. In addition, in the permanent magnet type synchronous motor 1, the rotating magnetic field of the stator 6 and the rotor 4 are synchronized. Therefore, the differential rotation mechanism 13 generates a difference in rotational speed ΔN _r between the rotor and the squirrel-cage rotor 17, and power can be generated by causing the squirrel-cage rotor 17 to cross the rotating magnetic field generated in the stator 6. It is configured as follows. Here, the configuration example in which the cage rotor 17 is a power generation coil is shown, but any rotor having a coil that can generate power across the rotating magnetic field generated in the stator 6 may be used.

FIG. 3 is a collinear diagram of the differential rotation mechanism 13 described above. Since the rotation of the rotor 4 is synchronized with the rotating magnetic field which is generated in the stator 6 can be regarded as identical to the rotational speed N _stator of the rotating magnetic field generated in the rotational speed N _rotor and the stator 6 of the rotor 4. The sun gear 14 is connected to the rotor shaft 2, the rotational speed N _S is equal to the rotational speed N _rotor of the rotor 4. The ring gear 16 is a reaction force element. As a result, it is possible to decelerate the rotational speed N _C of the carrier 15 that cage rotor 17 is coupled to the rotational speed N _rotor of the rotor 4. That without rotational speed N _C and the synchronization of the rotational speed N _rotor and the carrier 15 of the rotor 4, the difference .DELTA.N _r speed between them occurs, cage type rotor rotating magnetic field generated in the stator 6 17 Electric power can be generated by crossing the coil.

  In the configuration shown in FIG. 2, the electric power generated in the coil of the cage rotor 17 by crossing the rotating magnetic field generated in the stator 6 is supplied to the Peltier element 10 through the slip ring 18. As a result, the heat generated in the rotor 4 is taken away by the heat absorbing portion 8 of the Peltier element 10 and the rotor 4 is cooled. The heat of the heat generating part 9 is transferred to oil flowing through the cooling passage 7 arranged in contact with the heat generating part 9. Therefore, since the configuration is such that the heat of the rotor 4 is actively taken away, demagnetization of the permanent magnet 3 inserted into the rotor 4 can be prevented or suppressed. Moreover, the performance fall of the motor 1 by heat can be prevented or suppressed.

FIG. 4 schematically shows another example of the cooling device for the motor 1 according to the present invention. A power generation coil 17 is disposed so as to cross the rotating magnetic field generated in the stator 6 as the power source 11 of the Peltier element 10. Further, by using a transmission mechanism having a differential action, a rotational speed difference ΔN _r is generated between the rotor 4 and the power generation coil 17 so that power is generated from the rotating magnetic field generated in the stator 6 and the power generation coil. It is configured. The power generating coil 17 includes a cage rotor 17 around which a coil is wound. The sun gear 14 of the differential rotation mechanism 13 is connected to B over data shaft 2 as an input element, the ring gear 16 is connected to your type rotor 17 whether as an output element, the carrier 15 is the reaction element Yes. Further, the rotating magnetic field generated in the stator 6 by the slip ring 18 and the electric power generated by the cage rotor 17 can be supplied to the Peltier element 10. In addition, in the permanent magnet type synchronous motor 1, the rotating magnetic field of the stator 6 and the rotor 4 are synchronized. Therefore, the differential rotation mechanism 13 generates a rotational speed difference ΔN _r between the rotor 4 and the squirrel-cage rotor 17 and causes the squirrel-cage rotor 17 to cross the rotating magnetic field generated in the stator 6 to generate power. It is configured to be able to. Here, the configuration example in which the cage rotor 17 is a power generation coil is shown, but any rotor having a coil that can generate power across the rotating magnetic field generated in the stator 6 may be used.

6 is a collinear diagram of the differential rotation mechanism 13 shown in FIG. Since the rotation of the rotor 4 is synchronized with the rotating magnetic field which is generated in the stator 6 can be regarded as identical to the rotational speed N _stator of the rotating magnetic field generated in the rotational speed N _rotor and the stator 6 of the rotor 4. The sun gear 14 is connected to the rotor shaft 2, the rotational speed N _S is equal to the rotational speed N _rotor of the rotor 4. The carrier 15 is a reaction force element. As a result, it is possible to decelerate the rotational speed N _R of the ring gear 16 which cage rotor 17 is coupled to the rotational speed N _rotor of the rotor 4. That does not speed N and _R are synchronous rotational speed N _rotor and the ring gear 16 of the rotor 4, the difference .DELTA.N _r speed between them occurs, cage type rotor rotating magnetic field generated in the stator 6 Electricity can be generated by crossing 17 coils.

In the configuration shown in FIG. 4, the difference in rotational speed ΔN _r between the rotor 4 and the squirrel-cage rotor 17 is larger than that in the example shown in FIG. That is, the planetary shown in FIG. 4 fixes the carrier 15 so that the rotational speed of the torque input to the sun gear 14 is decelerated and reversed and output from the ring gear 16. Therefore, the amount of power that can be supplied to the Peltier element 10 can be increased as compared to the configuration example shown in FIG. The electric power generated in the coil of the cage rotor 17 by crossing the rotating magnetic field generated in the stator 6 is supplied to the Peltier element 10 via the slip ring 18. As a result, the heat generated in the roller 3 is taken by the heat absorbing portion 8 of the Peltier element 10 and cooled. The heat of the heat generating part 9 is transferred to oil flowing through the cooling passage 7 arranged in contact with the heat generating part 9. Therefore, since the configuration is such that the heat of the rotor 4 is actively taken away, demagnetization of the permanent magnet 3 inserted into the rotor 4 can be prevented or suppressed. Moreover, the performance fall of the motor 1 by heat can be prevented or suppressed.

  In the configuration shown in FIG. 2 or 4, the differential rotation mechanism 13 is always rotated while the rotor 4 is rotating, and drag loss occurs in the motor. Further, since electric power is generated while the rotor 4 is rotating, cooling by the Peltier element 10 is continued, and there is a possibility that an increase in oil agitation loss due to an increase in oil viscosity may occur.

FIG. 6 schematically shows an example in which the power generation amount of the cage rotor 17 can be adjusted. The brake mechanism 19 according to the present invention is configured so that the rotation of the squirrel-cage rotor 17 is restricted and the amount of power generation can be adjusted. That is provided a rotational speed N _R of the ring gear 16 so that it can be controlled by engaging or releasing the braking mechanism 19. The carrier 15 is a reaction force element. Further, the rotating magnetic field generated in the stator 6 by the slip ring 18 and the electric power generated by the cage rotor 17 can be supplied to the Peltier element 10. In addition, an ECU 20 is provided for adjusting the electric power generated from the rotating magnetic field generated in the stator 6 and the cage rotor 17 by controlling the engagement or release of the brake mechanism 19.

FIG. 7 shows an alignment chart of the differential rotation mechanism 13 shown in FIG. Since the rotation of the rotor 4 is synchronized with the rotating magnetic field which is generated in the stator 6 can be regarded as identical to the rotational speed N _stator of the rotating magnetic field generated in the rotational speed N _rotor and the stator 6 of the rotor 4. The sun gear 14 is connected to the rotor shaft 2, the rotational speed N _S is equal to the rotational speed N _rotor of the rotor 4. Therefore it is possible to decelerate the rotational speed N _R of the ring gear 16 which cage rotor 17 is coupled to the rotational speed N _rotor of the rotor 4. That does not speed N and _R are synchronous rotational speed N _rotor and the ring gear 16 of the rotor 4, the difference .DELTA.N _r speed between them occurs, cage type rotor rotating magnetic field generated in the stator 6 Electricity can be generated by crossing 17 coils. Also for example, when the rotational speed N _C of the carrier 15 by the brake mechanism 19 is not controlled, the rotational speed difference .DELTA.N _r between the rotational speed N _R of the rotational speed N _rotor and the ring gear 16 of the rotor 4 is reduced, the motor 1 The drag loss can be reduced or suppressed. If the rotational speed N _C of the carrier 15 is controlled, the rotational speed difference .DELTA.N _r between the rotational speed N _R of the rotational speed N _rotor and the ring gear 16 of the rotor 4 is increased by the brake mechanism 19 to the contrary Therefore, the electromotive force can be obtained by the difference ΔN _r between the rotation speeds.

  FIG. 8 shows an example of control of the brake mechanism 19. First, it is determined whether or not the absolute value of the required torque capacity value for the motor 1 is 0 (step S1).

  If a negative determination is made in step S1, this routine is temporarily terminated without performing any particular control. On the other hand, if a positive determination is made in step S1, it is determined whether or not the motor 1 temperature exceeds the demagnetization temperature (step S2).

If a negative determination is made in step S2, this routine is temporarily terminated without performing any particular control. On the contrary, if the determination in step S2 is affirmative, since the demagnetization occurs due to the high temperature of the motor 1 and the performance of the motor 1 deteriorates, the engagement state of the brake is controlled to control the ring. The rotational speed N _R of the gear 16 is controlled (step S3).

For example the absolute value of the required torque T _rq to the motor 1 is 0, or if the temperature of the rotor 4 is equal to or less than the demagnetization temperature T _mf, the rotational speed N _C of the carrier 15 by the brake mechanism 19 is not restricted. Therefore the rotational speed difference .DELTA.N _r between the rotational speed N _R of the rotational speed N _rotor and the ring gear 16 of the rotor 4 is reduced, the drag loss motor 1 can be reduced or be suppressed. On the contrary, when the absolute value of the required torque T _rq to the motor 1 is not 0 and the temperature of the rotor 4 exceeds the demagnetization temperature T _mf , the rotation speed N of the ring gear 16 is controlled by the brake mechanism 19. _R is regulated. Therefore the rotational speed difference .DELTA.N _r between the rotational speed N _R of the rotational speed N _rotor and the ring gear 16 of the rotor 4 is increased, it is possible to obtain an electromotive force by a difference .DELTA.N _r of the rotation speed.

Configuration shown in FIG. 6, it is possible to cool the rotor 4 when exceeding the demagnetization temperature T _mf, it is possible to prevent or suppress the performance degradation of the motor 1 due to heat. Further, when the demagnetization temperature is equal to or lower than T _mf , the rotational speed difference ΔN _r can be reduced, so that the drag loss of the motor 1 can be reduced.

As a control parameter of the brake mechanism 19, a current value A _M energized to the motor 1 may be used instead of the demagnetization temperature T _mf . That is, the amount of work of the motor 1 and the amount of heat generated in the motor 1 can be obtained in advance from experiments, simulations, and the like from the current value A _M energized to the motor 1, so that the same control as in the above example can be performed. .

It is a figure which shows typically the reference example of the cooling device of the motor which concerns on this invention. It is a figure which shows typically an example of the cooling device of the motor which concerns on this invention. It is an alignment chart at the time of connecting a power generation coil to a carrier of a differential rotation mechanism. It is a figure which shows typically the other structural example of the cooling device of the motor which concerns on this invention. It is an alignment chart at the time of connecting the coil for power generation to the ring gear of a differential rotation mechanism. It is a figure which shows typically the structural example which enabled adjustment of the electric power generation amount by the coil for electric power generation. It is a collinear diagram when the ring gear of the differential rotation mechanism is a coil for power generation. Is a flowchart illustrating an example control of the brake mechanism.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Motor, 2 ... Rotor shaft, 4 ... Rotor, 6 ... Stator, 10 ... Peltier element, 13 ... Differential rotation mechanism, 16 ... Cage type rotor, 18 ... Brake mechanism

Claims (7)

In a motor cooling device in which a stator that generates torque by electromagnetic action between the rotor and an outer peripheral side of the rotor attached to the rotor shaft is disposed.
A thermoelectric element is provided between the rotor shaft and the rotor, and the thermoelectric element is configured such that when energized, the rotor shaft side becomes a heat generating portion and the rotor side becomes a heat absorbing portion, and the rotor shaft A cooling mechanism that takes heat away from the
Said rotor shaft or said rotor, the stator and the power generation coil to produce an electromotive force mounted by the relative rotation of, be configured to power generated by the power generating coil is supplied to the thermoelectric element Rukoto A motor cooling device. The rotor includes a permanent magnet, and the stator includes a coil that generates a rotating magnetic field,
Wherein between the generating coil and before Symbol rotor shaft or said low data, the rotation from the rotor shaft or the rotor of the rotor rotation speed of the generator coil with transmitting torque to the coils for the power generation The motor cooling device according to claim 1, further comprising a transmission mechanism that is different from the number . The transmission mechanism includes three rotary elements for differentially rotate relative to each other, any one of the rotating element is connected to the rotor shaft or said rotor, the other one of the rotary elements is connected before Symbol power generating coil 3. The motor cooling apparatus according to claim 2 , further comprising a differential rotating mechanism in which the other rotating element is a reaction force element . Motor cooling device according to claim 3, characterized in that it comprises further a braking mechanism for selectively stopping the rotation of the front Symbol rotating element. And temperature determining means for determining the temperature of the pre-SL motor is a predetermined threshold value or more,
And brake control means for stopping the rotation of the reaction element by the brake Organization when the temperature of the motor is greater than or equal to the threshold value is determined by said determining means
Motor cooling device according to claim 4, characterized in that it further comprises a. Before SL threshold, the motor of the cooling device according to claim 5, wherein the magnetic force of the rotor is a predetermined temperature as a temperature decrease. Before SL cooling mechanism, a motor cooling device according to any one of claims 1 to 6, wherein the this include a cooling passage for circulating the cooling heat transport medium through said rotor shaft.

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