JP2007147204A - Cooling method of exothermic part, cooling device of exothermic part, and in-wheel motor using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cooling device of an exothermic part capable of eliminating restriction of a position relation of the exothermic part and a condenser and improving the degree of freedom in layout. <P>SOLUTION: The cooling device cools a stator 3 by allowing a coolant to flow in cooling passages 12a to 12f connected thermally to the stator 3, turns the coolant turned to vapor phase discharged from the cooling flow passages 12a to 12f to liquid phase in a condenser 19 and returns the coolant to a reservoir tank 21, and allows the coolant to self-circulate by arranging the reservoir tank further above in the perpendicular direction than the cooling flow passages 12a to 12f. On the other hand, a check valve 23 is provided on the further upstream side than the stator 3 of the cooling flow passages 12a to 12f and reverse flow of the coolant from the cooling flow passages 12a to 12f to the reservoir tank 21 is prevented, while, in the case the set temperature of the coolant of the cooling flow passages 12a to 12f is a saturated temperature or higher, the density of the coolant further on downstream side than the condenser 19 of the cooling flow passages 12a to 12f is lowered. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention belongs to the technical field of a cooling method for a heat generating portion, a cooling device for the heat generating portion, and an in-wheel motor using the same.

In the conventional heat generating part cooling device, the condenser is arranged vertically above the heat generating part, and the refrigerant liquidified by the condenser is dropped to the heat generating part below using the weight of the refrigerant, A pumpless cooling system is realized by pushing the liquid-phase refrigerant downstream of the condenser upward using the high-pressure refrigerant vaporized in the heat generating part (for example, Patent Document 1). reference).
JP 2005-195226 A

  However, in the above-described prior art, because the refrigerant is circulated using the density difference between the liquid-phase refrigerant and the gas-phase refrigerant, it is necessary to arrange the condenser vertically above the heat generating portion. There was a problem that the degree of freedom was low.

  The present invention has been made paying attention to the above object, and the purpose of the present invention is to eliminate the restriction on the positional relationship between the heat generating part and the condenser, and to improve the layout flexibility. An object is to provide a cooling method, a cooling device for a heat generating portion, and an in-wheel motor using the same.

In order to achieve the above object, the present invention provides:
The refrigerant is circulated through a cooling channel thermally connected to the heat generating unit to cool the heat generating unit, and the vaporized refrigerant discharged from the cooling channel is converted into a liquid phase by a condenser and returned to the reservoir tank. In addition, the reservoir tank is arranged vertically above the cooling flow path to allow the refrigerant to self-circulate,
A check valve is provided on the upstream side of the heat generating portion of the cooling flow path to prevent the reverse flow of the refrigerant from the cooling flow path to the reservoir tank, and the temperature of the refrigerant in the cooling flow path is equal to or higher than the saturation temperature. When the temperature rises to a set temperature, the density of the refrigerant on the downstream side of the condenser in the cooling flow path is reduced.

  In the heat generating part cooling method of the present invention, the liquid phase refrigerant stored in the reservoir tank is supplied to the cooling flow path by gravity, and the heat generating part is cooled by removing heat from the heat generating part. Since the high-pressure refrigerant vaporized in the heat generating part is prevented from moving upstream, that is, to the reservoir tank side by the first check valve, it moves to the condenser side and becomes liquid phase. At this time, the liquid-phase refrigerant on the downstream side of the condenser is pushed further downstream by the expanded gas-phase refrigerant, so that the liquid-phase refrigerant rises against gravity and is returned to the reservoir tank. Thereby, circulation of the refrigerant | coolant of a reservoir tank-> cooling flow path-> condenser-> reservoir tank is realizable.

  Here, the positional relationship between the heat generating part and the condenser, particularly when the heat generating part is arranged vertically above the condenser, the cooling flow path from the heat generating part to the reservoir tank becomes longer, so the pressure of the gas phase refrigerant Is small, the liquid-phase refrigerant cannot be pushed up, and the first check valve cannot be opened due to the residence of the gas-phase refrigerant. Therefore, the liquid phase refrigerant from the reservoir tank cannot be supplied to the heat generating part, and there is a possibility that a so-called “dry-out” may occur in which the heat generating part exceeds the design allowable temperature change and the temperature rises.

On the other hand, in this invention, when the temperature of the refrigerant | coolant of a cooling flow path rises to the setting temperature which is a temperature more than saturation temperature, the density of the refrigerant | coolant downstream from the condenser of a cooling flow path is reduced. That is, if the refrigerant exceeds the saturation temperature and dryout may occur, the first check valve cannot be opened by reducing the pressure required to push up the liquid-phase refrigerant. It is intended to suppress and prevent the occurrence of dryout.
As a result, even when the heat generating part is arranged vertically above the condenser, it is possible to prevent the occurrence of dryout. Therefore, there is no restriction on the positional relationship between the heat generating part and the condenser, and the degree of freedom in layout is reduced. Improvements can be made.

  Hereinafter, the best mode for carrying out the present invention will be described based on Examples 1 to 3.

First, the configuration will be described.
FIG. 1 is a side view of a rear part of a vehicle, showing a state in which an in-wheel motor incorporating a cooling device for a heat generating part of Example 1 is mounted on a vehicle. In FIG. 1, 101 is a vehicle body, 102 is a tire, 103 is a wheel, Reference numeral 105 denotes an in-wheel motor, and 110 denotes a tire house.

  FIG. 2 is a perspective view of the suspension device showing a vehicle body mounting state of the in-wheel motor 105 according to the first embodiment. The tire 102 is connected to the vehicle body 101 by a double wishbone suspension device 107 including a pair of upper and lower arms 107a and 107b and a shock absorber 107c. An in-wheel motor (hereinafter abbreviated as a motor) 105 has an output-side housing surface fixed to an axle (not shown).

3 is a cross-sectional view of the motor 105 of the first embodiment, and FIG. 4 is a cross-sectional view of S4-S4 in FIG.
The motor 105 includes a housing 1, end plates 2 a and 2 b, a stator 3, a rotor (heat generating part) 4, a motor shaft 7, and a motor bearing 8.

  The stator 3 is fixed to the inner periphery of the housing 1. On the inner periphery of the stator 3, six stator pole portions 3 ′ are projected at a circumferential direction pitch of 60 °. A motor coil 5 is wound around each stator convex pole portion 3 '.

  The rotor 4 is formed integrally with the motor shaft 7, and the outer periphery is surrounded by the stator 3. Both end portions of the motor shaft 7 are rotatably supported by the end plates 2a and 2b via the motor bearings 8. Four rotor magnets 6 are arranged on the peripheral edge of the rotor 4 along the axial direction of the motor shaft 7 at a pitch of 90 ° in the circumferential direction.

  The motor 105 according to the first embodiment includes a reservoir tank 21 in which a cooling refrigerant is stored. An air release port 22 is formed on the upper surface of the reservoir tank 21. The reservoir tank 21 is connected to the flow path 9, and the flow path 9 communicates with the flow path 10 via a check valve (first check valve) 23. The check valve 23 allows the flow of the refrigerant from the flow path 9 to the flow path 10 and blocks the flow of the refrigerant from the flow path 10 to the flow path 9.

  The flow path 10 includes six cooling flow paths 12a, 12b, 12c, 12d, 12e, and 12f provided in the stator 3 at a circumferential pitch of 60 ° via an arc-shaped flow path 11 provided in the end plate 2a. (Hereinafter abbreviated as 12a to 12f). Each of the cooling flow paths 12a to 12f has the same diameter and communicates with the flow path 14 via an arc-shaped flow path 13 provided in the end plate 2b. The flow path 14 communicates with a condenser (condenser) 19. The capacitor 19 communicates with the flow path 20 via the check valve 25.

The flow path 20 communicates with the reservoir tank 21. The check valve 25 is a check valve that permits the flow of refrigerant from the flow path 14 to the flow path 20 and prevents the flow of refrigerant from the flow path 20 to the flow path 14.
The flow paths 13, 14, and 20 constitute a refrigerant discharge flow path that returns the refrigerant discharged from the cooling flow paths 12 a to 12 f to the reservoir tank 21.

The flow path 9 branches from the position between the reservoir tank 21 and the check valve 23 to the flow path 15. The flow path 15 communicates with the flow path 16 via a check valve (second check valve) 24. The check valve 24 allows the flow of the refrigerant from the flow path 15 to the flow path 16 and blocks the flow of the refrigerant from the flow path 16 to the flow path 15.
The flow paths 9, 10 and 11 constitute a refrigerant supply flow path for supplying a refrigerant from the reservoir tank 21 to the cooling flow paths 12a to 12f.

  The flow channel 16 communicates with the flow channel 17 via the on-off valve 26. The on-off valve 26 opens and closes according to the temperature of the refrigerant in the flow path 17 (low density refrigerant supply flow path temperature). The flow path 17 is disposed in a space between the two stator convex pole portions 3 ′, and communicates with the flow path 18 via the check valve 27. The flow path 17 is disposed between the stator convex pole portions 3 ′, and is set so that the amount of heat received from the motor 105 is larger than the cooling flow paths 12 a to 12 f disposed inside the stator 3. Further, the flow path 17 is disposed at a position near the cooling flow path 12d at the lowest vertical position among the cooling flow paths 12a to 12f in order to obtain a large position head (gravity potential).

  Low density refrigerant supply that is thermally connected to the condenser 19 by the flow paths 15, 16, 17, and 18 and that communicates the upstream side of the check valve 23 of the flow path 9 and the downstream side of the condenser 19 of the flow path 20. A flow path is configured.

  The check valve 27 is a check valve that permits the flow of the refrigerant from the flow path 17 to the flow path 18 and blocks the flow of the refrigerant from the flow path 18 to the flow path 17. The flow path 18 communicates with the flow path 20 between the check valve 25 of the flow path 20 and the reservoir tank 21 and at the vertical lowest position of the flow path 20. The low-density refrigerant supply flow paths (flow paths 16, 17, 18) are not in communication with any of the flow paths 11, 12a to 12f, 13.

  Next, the opening / closing structure of the opening / closing valve 26 will be described. 5 and 6 show the closed state and the open state of the on-off valve 26, respectively. The on-off valve 26 is connected via a rod 28 to a temperature detection coil unit (low density refrigerant supply channel temperature detection means) 29 fixed at a predetermined position in the channel 17. The temperature detection coil unit 29 is formed of a bimetal, a shape memory alloy, or the like that expands when the temperature in the flow path becomes high and degenerates when the temperature becomes low. The on-off valve 26 is closed and set when the temperature in the flow path is equal to or lower than the set temperature. It is set to open when the temperature is higher. Here, the set temperature at which the on-off valve 26 opens is set to a temperature higher than the temperature range in which the refrigerant in the flow path 17 evaporates.

The rod 28 and the temperature detection coil unit 29 constitute valve opening / closing means for opening the opening / closing valve 26 when the temperature of the rotor 3 is equal to or higher than the set temperature.
Further, when the temperature of the refrigerant in the cooling flow paths 12a to 12f rises to the saturation temperature or higher by the flow path 17, the on-off valve 26, the rod 28, and the temperature detection coil 29, the downstream of the condenser 19 in the refrigerant discharge flow path. Refrigerant density lowering means for reducing the density of the refrigerant on the side is configured.

Next, the operation of the refrigerant density lowering means, which is the main component of the present invention, will be described.
[Refrigerant circulation operation]
FIG. 7 is a diagram illustrating the flow of the refrigerant of the first embodiment. In FIG. 7, when the flow F1 passes through the reservoir tank 21 and the flow path 9, the refrigerant is in a liquid phase. When the inside of the cooling flow paths 12a to 12f is not in a boiling state and the pressure of the internal refrigerant is low, the flow F1 in the flow path 9 passes through the check valve 23 and becomes the liquid phase flows F2 and F3 in the flow paths 10 and 11.

  The liquid phase flow F3 becomes the flows F4a to F4f in the cooling channels 12a to 12f provided in the stator 3. These flows are supplied to the cooling channels 12a to 12f by gravity acting on the liquid. Iron loss of the motor 105 (a combination of hysteresis loss and eddy current loss that occurs in the iron core when AC magnetic flux passes through the iron core, a general term for power loss that occurs in the iron core) and copper loss (as a coil) In the case where there is a large amount of heat generated due to the electric resistance of the wound electric wire, the flow F4a to F4f is liquid at the portion close to the stator heat source of the cooling channels 12a to 12f. Phase change from phase to gas phase.

  When the state changes from the liquid phase to the gas phase, the pressure in the flow path becomes larger than the liquid phase state due to the position head from the reservoir tank 21 and the flow resistance of the flow path. Since the flow of the vapor phase of the refrigerant is restricted in the direction of F4a to F4f by the valve 23, the vapor phase refrigerant does not flow backward to the upstream side (flow channel 9 side) from the check valve 23.

  The flow of the refrigerant vaporized in the stator 3 is merged in the flow path 13 or the flow path 14 in the vapor phase, and flows into the capacitor 19 as the vapor flow F6 (F5 → F6 except for F4a) as described above (flow). F12). At this time, the liquid-phase refrigerant existing in the capacitor 19 and the flow path 20 becomes gravity after passing through the check valve 25 due to a pressure increase caused by vaporization of the liquid-phase refrigerant in the stator 3 as described above. Accordingly, the liquid phase flow F13 returns to the reservoir tank 21.

  Here, when the pressure when the liquid-phase refrigerant in the cooling flow paths 12 a to 12 f in the stator 3 is vaporized is not sufficient, the liquid-phased refrigerant existing in the flow path 20 is pushed up to the reservoir tank 21. The gas-phase refrigerant stays in the cooling flow paths 12a to 12f. At this time, the pressure on the flow path 10 side of the check valve 23 becomes higher than the pressure on the flow path 9 side, so that the check valve 23 does not open and no liquid-phase refrigerant exists in the cooling flow paths 12a to 12f. A state appears. As a result, a so-called “dry out” occurs in which the temperature of the cooling flow paths 12 a to 12 f exceeds the design allowable range of the motor 105 and the temperature rises. In order to avoid this dry-out, the liquid-phase refrigerant present in the flow path 20 is returned to the reservoir tank 21 to discharge the gas-phase refrigerant in the cooling flow paths 12a to 12f, and the check valve 23 is opened. It is necessary to take in liquid phase refrigerant.

  In the first embodiment, the liquid phase flow F2 ′ is caused to flow from the reservoir tank 21 through the flow path 9 to the flow path 15 branched on the reservoir tank side of the check valve 23, and into the flow path 16 via the check valve 24. Supply liquid phase flow F7. This liquid phase flow F7 is supplied into the flow path 17 via the on-off valve 26 that opens and closes in the temperature state of the flow path 17.

  In the first embodiment, the flow path 17 is disposed between the motor coils 5 that receive a larger amount of heat than the cooling flow paths 12a to 12f. For this reason, when the diameter and length of the pipes of the flow path 17 and the cooling flow paths 12a to 12f are the same, the refrigerant in the flow path 17 boils earlier in time than the refrigerant in the cooling flow paths 12a to 12f. To do. The temperature at which the on-off valve 26 opens is set higher than the temperature range in which the refrigerant in the flow path 17 evaporates.

  Therefore, the refrigerant supplied to the flow path 17 is vaporized before the cooling flow paths 12a to 12f are dried out and supplied to the flow path 20 (flow F8 → F9). Is pushed up to the reservoir tank 21. As a result, the pressure on the downstream side of the check valve 23 becomes lower than the pressure on the upstream side, so that the check valve 23 is opened and the liquid-phase refrigerant is supplied to the cooling channels 12a to 12f. Thereafter, since the temperature of the refrigerant in the flow path 17 is lower than the set temperature, the on-off valve 26 is closed and supply of the refrigerant into the flow path 17 is stopped.

  The gas-phase refrigerant discharged from the flow path 17 returns to the reservoir tank 21 after returning the liquid-phase refrigerant in the flow path 20 to come into contact with the liquid-phase refrigerant in the flow path 20 that is cooled by the capacitor 19 and sufficiently lower than the saturation temperature. By doing so, it rapidly condenses and changes to the liquid phase.

[Dry-out prevention principle]
Hereinafter, the refrigerant density lowering means (flow path 15, check valve 24, flow path 16, on-off valve 26, flow path 17, check valve 27, flow path 18) of Example 1 of FIG. 7 is not provided, and FIG. The open / close state of the check valve 23 is considered under the condition that the refrigerant is present below the Ho of the flow path 14 as shown in FIG. The pressure Pin on the upstream side of the check valve 23 shown in FIG. 7 is expressed by the following equation (1).
Pin = Pt + ρi · g · Hi (1)
Here, Pt is the pressure applied to the coolant level in the reservoir tank 21, ρi is the density of the coolant at the position of the pressure Pin, g is the acceleration of gravity, and Hi is the position from the position of the pressure Pin to the coolant level in the reservoir tank 21. It is height.

On the other hand, the pressure Pout on the downstream side of the check valve 23 is expressed by the following equation (2).
Pout = Pt + ΔPls + ρo · g · Ho (2)
Here, ρo is the density of the refrigerant in the flow path 20, g is the acceleration of gravity, Ho is the height from the position of the pressure Pout to the position where the flow path 20 communicates with the reservoir tank 21, ΔPls is the flow path 14, the capacitor 19 and This is the flow resistance when the refrigerant in the flow path 20 is made to flow.

If the resistance of the check valve 23 is ignored, Pin> Pout, that is, if ρi · g · Hi> ΔPls + ρo · g · Ho, the check valve 23 is opened, and if Pin <Pout, the valve is closed. Here, assuming that the coolant is water, the water temperature in the Pin and the water temperature in the channel 20 is 50 ° C., and Hi is 0.5 m and Ho is 0.6 m, the following equations (3) and (4) are established. To do.
ρi ・ g ・ Hi = 988 × 9.8 × 0.5 = 4.84 kPa (kN / m ² )… (3)
ρo ・ g ・ Ho = 988 × 9.8 × 0.6 = 5.81 kPa (kN / m ² )… (4)
When Pt is a standard atmospheric pressure of 101.3 kPa, the following equation (5) is obtained.
Pt ＋ ρo ・ g ・ Ho = 107.1 kPa (5)

The saturation temperature for a water saturation pressure of 107.1 kPa is approximately 101.3 ° C. According to the experimental results, the saturation temperature is about 102 ° C., and according to the saturated steam table of water, the saturation pressure for the saturation temperature of 102 ° C. is 109.6 kPa. From these results, the following equation (6) is established.
ΔPls = 109.6−107.1 = 2.5 kPa (6)

  ΔPls is in the same order as ρo · g · Ho. Accordingly, as in the first embodiment, the refrigerant in the flow path 20 returning from the capacitor 19 to the reservoir tank 21 is sent to the reservoir tank 21 using an external heat source (refrigerant gas-phased in the flow path 17). Pin> Pout can be achieved, and it can be seen that the check valve 23 opens even during dryout, and as a result, dryout can be avoided.

[Dry-out prevention]
FIG. 8 is a time chart showing the dryout prevention effect of the first embodiment. In addition, the broken line of Fig.8 (a) is a refrigerant density reduction means (flow path 15, check valve 24, flow path 16, on-off valve 26, flow path 17, check valve with respect to the structure of Example 1 as a comparative example. 27 shows a temperature change in the cooling channel 12a when the channel 18) is omitted.

  Tsat1 in FIG. 8A represents the saturation temperature of the refrigerant in the cooling flow path 12a. When the temperature of the refrigerant in the cooling channel 12a is constant at Tsat1, the inside of the channel is in a boiling state, and the refrigerant is in a gas-liquid two-phase state. I indicates a normal operation state in which the temperature in the cooling flow path 12a is lowered by the supply of the refrigerant passing through the check valve 23 from the boiling state.

  II shows a state in which the temperature of the refrigerant in the cooling flow path 12a is lowered due to the supply of the refrigerant through the check valve 23 after the refrigerant in the cooling channel 12a changes from the boiling state to the gas phase only and becomes the dry-out state due to the temperature rise. Dryout is preferably avoided as much as possible because its maximum temperature may exceed the design tolerance. In addition, since III is a state where the boiling state is changed to the dry-out state and the temperature continues to rise, it must be avoided.

  FIG. 8C shows a temperature change in the flow path 17 of the first embodiment. Here, Tsat1 is the saturation temperature of the refrigerant in the cooling flow path 12a, Tsat2 is the saturation temperature of the refrigerant in the flow path 17, and Top is a preset valve opening temperature (set temperature) of the on-off valve 26. ing. The set temperature Top is set such that Top> Tsat1.

  As described above, since the flow path 17 is located between the motor coils 5 that receive a larger amount of heat than the cooling flow paths 12a to 12f, the flow path 17 reaches the boiling state (temperature Tsat2) earlier than the cooling flow paths 12a to 12f. Thereafter, only the gas phase is obtained, and the temperature in the flow path 17 starts to rise. That is, when the temperature in the flow path 17 reaches a temperature near Top, the refrigerant in the cooling flow path 12a starts to boil.

  At time t1 in FIG. 8 (b), the temperature in the flow path reaches Top and the on-off valve 26 opens, so that the flow path 15 goes to the flow path 17 via the check valve 24, the flow path 16 and the on-off valve 26. Refrigerant is supplied. When the refrigerant is supplied to the flow path 17, since the temperature in the flow path 17 is higher than the saturation temperature Tsat2 of the refrigerant, evaporation immediately starts and the temperature of the refrigerant in the flow path 17 becomes Tsat2. Thereafter, the state in which the refrigerant is supplied into the flow path 17 continues. In the first embodiment, the temperature Tcl at which the on-off valve 26 closes is Tcl≈Tsat2. Therefore, after the temperature in the flow path reaches Tcl, after the time delay necessary for the degeneration of the temperature detection coil unit 29, the on-off valve 26 is closed (time t2 in FIG. 8B).

  After the temperature in the cooling flow path 12a rises again and the flow path is in the gas-liquid two-phase state again, when the flow path temperature reaches Top, the on-off valve 26 opens (at the time of FIG. 8 (b)). t3) The above cycle is repeated.

  A solid line in FIG. 8A indicates a temperature change in the cooling flow path 12a in the first embodiment. In the first embodiment, when the cooling channel 12 a is in a gas-liquid two-phase state, the on-off valve 26 is opened to return the refrigerant present in the channel 20 to the reservoir tank 21. Therefore, even when the pressure of the refrigerant in the cooling flow paths 12a to 12f is low, the pressure on the flow path 10 side of the check valve 23 is made lower than the pressure on the flow path 9 side of the check valve 23 to open the check valve 23. can do. As a result, since the liquid phase refrigerant can be supplied to the cooling flow paths 12a to 12f, dryout of the cooling flow paths 12a to 12f can be avoided.

  In the first embodiment, since the cooling channels 12a to 12f have the same diameter, the refrigerant flows more easily as the distance from the liquid level of the reservoir tank to the channel becomes longer due to the influence of the position head of the refrigerant. The longer the distance from the liquid surface to the flow path, the higher the saturation temperature due to the pressure increase at the position head. That is, the cooling flow path with a short distance from the reservoir tank liquid surface is more likely to dry out, and a difference occurs in the dry out situation in the flow path depending on the positions of the cooling flow paths 12a to 12f.

  For example, when the temperature in the flow path 17 for opening the on-off valve 26 is the saturation temperature of the refrigerant in the cooling flow path 12d, the cooling positioned vertically above the cooling flow path 12d when the on-off valve 26 is opened. The flow paths 12a, 12b, 12c, 12e, and 12f are already saturated, and there is a possibility that dryout has started.

  On the other hand, in the first embodiment, the set temperature Top for opening the on-off valve 26 is set to the cooling channel 12a having the shortest distance from the liquid level of the reservoir tank 21 to the channel among the cooling channels 12a to 12f. Since the refrigerant is set at the saturation temperature, it is possible to prevent dryout from occurring in all the cooling flow paths 12a to 12f.

  In the first embodiment, since the flow path 17 is installed in the vicinity of the cooling flow path 12d having the longest distance from the reservoir tank liquid surface among the cooling flow paths 12a to 12f, the cooling flow path 12a starts to dry out. However, when the on-off valve 26 is in the open state, the refrigerant can be reliably supplied to the flow path 17 by the position head larger than the position head of the cooling flow path 12a, and dryout occurs in all the cooling flow paths 12a to 12f. Can be avoided.

  Further, as described above, the saturation temperature Tsat2 in the flow path 17 becomes higher than the saturation temperature Tsat1 of the refrigerant in the cooling flow path 12a due to the pressure increase at the position head. Therefore, the saturation pressure of the refrigerant in the flow path 17 is higher than the saturation pressure of the refrigerant in the cooling flow path 12a, and the open / close valve 26 is in the open state even under conditions where the cooling flow path 12a starts to dry out. The liquid phase refrigerant existing in the flow path 20 can be reliably returned to the reservoir tank 21 by a saturation pressure larger than that of the cooling flow path 12a. In particular, it is possible to prevent the occurrence of dry-out even when a force other than gravity is applied to the vehicle such as traveling on a slope or acceleration of the vehicle.

  Further, in the cooling device for the heat generating part of Example 1, it is possible to prevent the occurrence of dry-out in the cooling flow paths 12a to 12f regardless of the position of the condenser 19 or the running state of the vehicle by the refrigerant density reducing means. The capacitor 19 can be disposed at an arbitrary position with respect to the stator 3.

  Therefore, when applied as a cooling device for an in-wheel motor, the capacitor 19 can be arranged at a position with high cooling efficiency, so that a complicated piping system from the vehicle body to the motor is not required, and the unsprung load is suppressed by pumpless. The motor efficiency can be maintained during traveling by increasing the cooling efficiency of the motor.

Next, the effect will be described.
In the cooling device for the heat generating portion of the first embodiment, the effects listed below can be obtained.

  (1) A cooling device that cools the stator 3 with a refrigerant, which is thermally connected to the stator 3 and that circulates the refrigerant, and is disposed vertically above the cooling channels 12a to 12f. A reservoir tank 21 for storing the refrigerant, a refrigerant supply channel (channels 9, 10 and 11) for supplying the refrigerant from the reservoir tank 21 to the cooling channels 12a to 12f, and an exhaust from the cooling channels 12a to 12f. A refrigerant discharge passage (flow passages 13, 14 and 20) for returning the generated refrigerant to the reservoir tank 21, a capacitor 19 provided in the refrigerant discharge passage for converting the vaporized refrigerant into a liquid phase, and a refrigerant supply flow A check valve 23 provided in the passage for preventing the reverse flow of the refrigerant from the cooling flow paths 12a to 12f to the reservoir tank 21, and the temperature of the refrigerant in the cooling flow paths 12a to 12f is equal to or higher than a saturation temperature. When the temperature is equal to or higher than the set temperature Top, refrigerant density lowering means (flow path 17, on-off valve 26, rod 28, and temperature detection coil 29) reduces the density of the refrigerant downstream of the condenser 19 in the refrigerant discharge flow path. And comprising. Thereby, there is no restriction on the positional relationship between the stator 3 and the capacitor 19, and the layout flexibility can be improved.

  (2) Refrigerant density lowering means is a low density refrigerant supply that is thermally connected to the stator 3 and communicates the upstream side of the check valve 23 in the refrigerant supply flow path and the downstream side of the condenser 19 in the refrigerant discharge flow path. The flow path (flow paths 15, 16, 17 and 18), the normally closed on-off valve 26 provided on the upstream side of the stator 3 of the low density refrigerant supply flow path, and the refrigerant temperature in the flow path 17 are set. When the temperature is equal to or higher than the temperature Top, valve opening / closing means (rod 28 and temperature detection coil unit 29) for opening the opening / closing valve 26 is provided. Accordingly, the refrigerant in the refrigerant discharge passage can be returned to the reservoir tank 21 using the heat of the stator 3 without adding another device as a refrigerant density lowering means, and the cooling effect of the stator 3 can be enhanced. Can do.

  (3) Since the low-density refrigerant supply flow path (flow path 17) is disposed at a position that receives a larger amount of heat from the stator 3 than the cooling flow paths 12a to 12f, before the cooling flow paths 12a to 12f cause dryout. In addition, the refrigerant in the flow path 17 can be vaporized to reliably return the refrigerant in the flow path 20 to the reservoir tank 21.

  (4) Since the low density refrigerant supply channel (channel 17) is arranged vertically below the other cooling channels 12a, 12b, 12c, 12e, and 12f excluding the cooling channel 12d, The refrigerant can be reliably supplied to the flow path 17 by the position head larger than the position head, and the occurrence of dry-out can be avoided in all the cooling flow paths 12a to 12f.

  (5) A temperature detection coil unit 29 for detecting the temperature of the flow path 17 is provided, and the valve opening / closing means opens the open / close valve 26 when the temperature of the flow path 17 is equal to or higher than the set temperature Top, so accurate temperature detection The refrigerant can be supplied to the flow path 17 based on the value, and the reliability of avoiding the dry-out can be improved.

  (6) Six cooling channels 12a to 12f are provided, and the valve opening / closing means opens the on-off valve 26 when the temperature of the channel 17 is equal to or higher than the saturation temperature of the refrigerant in the cooling channel 12a positioned at the uppermost vertical position. Since it is made to valve, dryout can be avoided in all the cooling flow paths 12a to 12f.

  (7) Check that is provided vertically below the check valve 23 and upstream of the opening / closing valve 26 of the low density refrigerant supply flow path to prevent the reverse flow of the refrigerant from the low density refrigerant supply flow path to the reservoir tank 21 A valve 24 was provided. Thereby, even when the check valve 23 cannot be opened by the pressure in the cooling flow paths 12a to 12f, the check valve 24 can be opened and the refrigerant can be supplied to the flow path 17. it can.

  (8) In the in-wheel motor in which the motor is incorporated in the wheel as a drive source of the wheel, the cooling device for the heat generating portion of Example 1 is incorporated in the wheel 103 as a cooling device for cooling the stator 3 of the motor 105. This eliminates the need for a complicated piping system from the vehicle body to the motor, and suppresses the unsprung load without a pump, while increasing the motor cooling efficiency and maintaining the motor efficiency during travel.

  (9) A cooling device that cools the stator 3 with a refrigerant, the reservoir tank 21 disposed in the cooling channels 12a to 12f thermally connected to the stator 3 vertically above the cooling channels 12a to 12f. The refrigerant stored in the refrigerant is vaporized in the cooling passages 12a to 12f and passed through the condenser 19 to become a liquid phase, and the refrigerant converted into a liquid phase in the condenser 19 is vaporized in the stator 3. The pressure is pushed up to the reservoir tank 21, and a first check valve 23 is provided in the refrigerant supply flow paths 12a to 12f to prevent the reverse flow of the refrigerant from the cooling flow paths 12a to 12f to the reservoir tank 21, and the cooling flow paths 12a to 12f. When the temperature of the refrigerant rises to a set temperature Top that is equal to or higher than the saturation temperature, the density of the refrigerant on the downstream side of the condenser 19 in the flow path 20 is reduced. Thereby, there is no restriction on the positional relationship between the stator 3 and the capacitor 19, and the layout flexibility can be improved.

  (10) A cooling device that cools the stator 3 with a refrigerant, the reservoir 3 thermally connecting the stator 3 and the cooling channels 12a to 12f, and storing the refrigerant vertically above the cooling channels 12a to 12f. 21 is arranged, a refrigerant is supplied from the reservoir tank 21 to the cooling passages 12a to 12f via the refrigerant supply circuit, and a check valve 23 is interposed between the refrigerant supply passage and the cooling passages 12a to 12f. Thus, the reverse flow of the refrigerant from the cooling flow paths 12a to 12f to the refrigerant supply circuit is prevented, the refrigerant vaporized in the cooling flow paths 12a to 12f is liquefied by the condenser 19, and the liquid phase refrigerant is discharged to the refrigerant. When returning to the reservoir tank 21 through the circuit and the temperature of the refrigerant in the cooling flow paths 12a to 12f rises to a set temperature Top that is equal to or higher than the saturation temperature, the density of the refrigerant that has been liquefied by the capacitor 19 is reduced. . Thereby, there is no restriction on the positional relationship between the stator 3 and the capacitor 19, and the layout flexibility can be improved.

  (11) Refrigerant is supplied to the cooling flow paths 12a to 12f that are thermally connected to the stator 3 from the reservoir tank 21 disposed vertically above the cooling flow paths 12a to 12f to cool the stator 3, and the stator 3 The refrigerant vaporized in step 1 is liquid-phased by the condenser 19 and then pushed up to the reservoir tank 21 using the pressure of the refrigerant vaporized in the stator 3, while the refrigerant vaporized in the stator 3 side When the temperature of the refrigerant in the cooling flow paths 12a to 12f rises to a set temperature Top that is a temperature equal to or higher than the saturation temperature, the density of the refrigerant that has been liquefied by the capacitor 19 is reduced. Thereby, there is no restriction on the positional relationship between the stator 3 and the capacitor 19, and the layout flexibility can be improved.

First, the configuration will be described.
FIG. 9 is a cross-sectional view of the motor 105 according to the second embodiment. In the heat generating unit cooling apparatus according to the second embodiment, the check valve 24 of the flow path 16 is omitted from the configuration of the first embodiment illustrated in FIG. It is a configuration. Other configurations are the same as those of the first embodiment.

Next, the operation of the refrigerant density lowering means, which is the main component of the present invention, will be described.
[Dry-out prevention]
FIG. 10 is a time chart showing the dryout prevention effect of the second embodiment. In addition, the broken line of Fig.10 (a) is a refrigerant density reduction means (the flow path 15, the flow path 16, the on-off valve 26, the flow path 17, the check valve 27, a flow path with respect to the structure of Example 2 as a comparative example. The temperature change in the cooling flow path 12a when 18) is omitted is shown.

  In FIG. 10 (c), since the flow path 17 is located between the motor coils 5 having a larger amount of heat than the cooling flow paths 12a to 12f, the flow path 17 is brought into a boiling state (temperature Tsat2) earlier than the cooling flow paths 12a to 12f. After that, only in the gas phase, the flow path temperature starts to rise. Here, Top is set in the same manner as in the first embodiment.

  When the temperature in the flow path reaches Top, the open / close valve 26 opens (time t1 in FIG. 10B), and the refrigerant is supplied to the flow path 17 via the flow paths 15 and 16 and the open / close valve 26. When the refrigerant is supplied, since the temperature in the flow path 17 is high, evaporation immediately starts and the flow path temperature becomes Tsat2. Thereafter, the state in which the refrigerant is supplied into the flow path 17 continues.

  Here, since the temperature Tcl in the flow path at which the on-off valve 26 is closed is Tcl> Tsat2, Tcl <Top, the time required for the temperature detection coil unit 29 to degenerate after the inside of the pipe reaches Tcl. After the delay, the on-off valve 26 is closed (time t2 in FIG. 10 (b)), and after the inside of the flow path 17 is in a gas-liquid two-phase state, the temperature of the flow path 17 rises and the temperature in the flow path is increased. Reaching Top again, the on-off valve 26 opens (time point t3 in FIG. 10B), and the above-described cycle is repeated.

  In the second embodiment, the check valve (the check valve 24 of the first embodiment) does not exist in the flow path 16, so that the cracking pressure (the pressure on the inlet side of the check valve is increased and a certain flow rate to the outlet side is recognized. The resistance is low by the amount of pressure). For this reason, compared with the cooling flow path 12d whose height from the flow path 17 and the reservoir tank 21 is substantially the same, the refrigerant is easily supplied to the flow path 17. As a result, even if the cooling flow path 12d is dried out for some reason, the refrigerant can be reliably supplied into the flow path 17 and the dry out of the cooling flow paths 12a to 12f is avoided. be able to.

Next, the effect will be described.
In addition to the effects (1) to (7), (9), and (10) of the first embodiment, the cooling device for the heat generating part of the second embodiment can obtain the following effects.

  (1) Since the low density refrigerant supply flow path (flow paths 15, 16, 17 and 18) includes only the opening / closing valve 26 as a valve body for increasing the flow resistance, the resistance of the low density refrigerant supply flow path is kept small. Thus, the supply of the refrigerant into the flow path 17 can be promoted, and the certainty of avoiding the dryout can be increased.

First, the configuration will be described.
FIG. 11 is a cross-sectional view of the motor 105 according to the third embodiment.
The cooling device for the heat generating portion of the third embodiment is different from the configuration of the second embodiment shown in FIG. 9 in that a three-way valve 31 is provided instead of the on-off valve 26 and a three-way valve 31 instead of the on-off valve 26, and a flow path 32, The configuration is different in that a temperature sensor (low density refrigerant supply flow path temperature detection means) 43, a temperature sensor (cooling flow path temperature detection means) 44, a controller 45 and an actuator 46 are added.

  The on-off valve 30 opens and closes by driving the actuator 46 and switches the communication state between the flow path 16 and the flow path 17. The three-way valve 31 is provided at a position between the flow path 17 and the flow path 18, and switches the communication path of the flow path 17 between the flow path 18 and the flow path 32 by driving the actuator 46. The flow path 32 communicates with the flow path 14 and the three-way valve 31. As shown in FIG. 11, the flow of the refrigerant when the flow path 17 and the flow path 18 communicate with each other is referred to as a path A, and the flow of the refrigerant when the flow path 17 and the flow path 32 communicate with each other is referred to as a path B.

  The temperature sensor 43 is installed in the flow path 17 and outputs the temperature in the flow path to the controller 45. The temperature sensor 44 is installed in the cooling channel 12 a and outputs the temperature in the channel (cooling channel temperature) to the controller 45. The controller 45 outputs a drive signal to the actuator 46 based on the temperature input signals from the temperature sensors 43 and 44, and controls the opening / closing of the on-off valve 30 and the switching of the communication path of the three-way valve 31, respectively.

  The controller 45 opens the on-off valve 30 when the temperature of the refrigerant in the flow path 17 is equal to or higher than the set temperature. In addition, the controller 45 switches the three-way valve 31 to the path B when the temperature of the refrigerant in the flow path 12a is lower than the heat resistant temperature set value that is higher than the set temperature and lower than the heat resistant temperature of the motor 105. When the temperature of the refrigerant in the flow path 12a is equal to or higher than the heat resistant temperature set value, the three-way valve 31 is switched to the path A.

  The controller 45 and the actuator 46 constitute valve opening / closing means for opening the opening / closing valve 30 when the temperature of the rotor 3 is equal to or higher than the set temperature. Further, the three-way valve 31 and the flow path 32 constitute route switching means.

Next, the operation of the refrigerant density lowering means, which is the main component of the present invention, will be described.
[Valve open / close control processing]
FIG. 12 is a flowchart showing the flow of a valve opening / closing control process executed by the controller 45 of the third embodiment. Each step will be described below. In this process, the operation signal ON of the motor 105 is set as a start trigger.

  In step S1, temperature signals T1 and T2 from the temperature sensor 43 installed in the flow path 17 and the temperature sensor 44 installed in the cooling flow path 12a are read, and the process proceeds to step S2.

  In step S2, it is determined whether or not the temperature T1 in the flow path 17 read in step S1 is equal to or higher than Top which is the saturation temperature in the cooling flow path 12a. If YES, the process proceeds to step S3. If NO, the process proceeds to step S6.

  In step S3, it is determined whether or not the temperature T2 of the cooling flow path 12a read in step S1 is equal to or higher than a preset heat-resistant temperature setting value Td. If YES, the process proceeds to step S4. If NO, the process proceeds to step S5. Here, the heat-resistant temperature set value Td is equal to or higher than a saturation temperature Tsat1 (Td ≧ Tsat1) known in advance by an experiment of the cooling flow path 12a and the heat-resistant temperature that the motor 105 can withstand is Tm. = Α · Tm (α <1, for example, 0.8).

  In step S4, a drive signal is output to the actuator 46 so that the on-off valve 30 is opened and the three-way valve 31 is in the path A, and the process proceeds to step S7.

  In step S5, a drive signal is output to the actuator 46 so that the on-off valve 30 is opened and the three-way valve 31 is in path B, and the process proceeds to step S7.

  In step S6, a drive signal is output to the actuator 46 so that the on-off valve 30 is closed and the three-way valve 31 is in the path B, and the process proceeds to step S7.

  In step S7, it is determined whether or not the motor 105 is OFF. If YES, the process proceeds to return, and if NO, the process proceeds to step S1.

[Valve open / close control operation]
When the temperature T1 in the cooling channel 12a is equal to or higher than the saturation temperature Top, the process proceeds from step S1 to step S2 to step S3 in the flowchart of FIG. 12, and the temperature T2 in the cooling channel 12a is set to the heat resistant temperature setting value. If it is equal to or greater than Td, the process proceeds from step S3 to step S4. In step S4, the on-off valve 30 is opened and the three-way valve 31 is switched to the path A. On the other hand, when the temperature T2 in the cooling flow path 12a is smaller than the heat resistant temperature set value Td, the process proceeds from step S3 to step S5, the on-off valve 30 is opened, and the three-way valve 31 is switched to the path B.

  When the temperature T1 in the flow path 17 is lower than the saturation temperature Top, the process proceeds from step S1 to step S2 to step S6. In step S6, the on-off valve 30 is closed and the three-way valve 31 is switched to the path B.

[Dry-out prevention]
As described in the first embodiment, when T1 ≧ Top, the flow path 17 has a vapor phase and a high temperature. Therefore, in the flowchart of FIG. 12, step S1, step S2, step S3, step S4 (or step S4). Proceeding to S5), the on-off valve 30 is opened and the refrigerant is supplied to the flow path 17. On the other hand, when T1 <Top, the on-off valve 30 is closed.

  Here, in step S3, when T2 ≧ Td, the cooling flow path 12a is in a dry-out state, and the motor temperature state greatly exceeds an appropriate temperature range. In this case, the process proceeds from step S3 to step S4, and the three-way valve 31 is switched to the path A. That is, similarly to the first and second embodiments, the flow path 17 and the flow path 20 are communicated with each other via the flow path 18, and the refrigerant existing in the flow path 20 is returned to the reservoir tank 21. Therefore, the pressure on the flow path 10 side of the check valve 23 can be made lower than the pressure on the flow path 9 side of the check valve 23 to open the check valve 23. Thereby, the refrigerant | coolant of the flow path 9 is supplied to the cooling flow paths 12a-12f, and the dry out of the cooling flow paths 12a-12f can be avoided.

  On the other hand, if T2 <Td, it is determined that the temperature is not in an appropriate temperature range, the process proceeds from step S3 to step S5, and the three-way valve 31 is switched to the path B. That is, the high-pressure steam in the flow path 17 is moved to the flow path 20 via the flow path 14 and the condenser 19 and returned to the reservoir tank 21. Therefore, the check valve 23 can be opened by making the pressure on the flow path 10 side of the check valve 23 lower than the pressure on the flow path 9 side of the check valve 23 without the vapor reaching the reservoir tank 21. Thereby, the refrigerant | coolant of the flow path 9 is supplied to the cooling flow paths 12a-12f, and the dryout of the cooling flow paths 12a-12f can be avoided.

Next, the effect will be described.
In addition to the effects (1) to (7), (9), (10) of the first embodiment and the effect (11) of the second embodiment, the cooling device for the heat generating part of the third embodiment has the following effects. can get.

  (1) The temperature sensor 44 that detects the temperature T2 of the cooling flow path 12a, and the flow path 17 when the temperature T2 is lower than the heat resistant temperature set value Td that is higher than the set temperature and lower than the heat resistant temperature of the rotor 3. And a path switching means for switching the communication position of the flow path 17 to the flow path 20 when the temperature T2 is equal to or higher than the heat resistant temperature set value Td. Therefore, when the temperature of the rotor 3 is not in an appropriate temperature range, the vapor phase refrigerant discharged from the flow path 17 directly reaches the reservoir tank 21 while avoiding the dry out of the cooling flow paths 12a to 12f. It is possible to prevent a decrease in cooling efficiency due to the above.

It is a vehicle rear part side view which shows the state which mounted the in-wheel motor to which the cooling device of the heat generating part of Example 1 was mounted in the vehicle. It is a perspective view of a suspension device showing a vehicle body attachment state of in-wheel motor 105 of Example 1. 1 is a cross-sectional view of a motor 105 according to a first embodiment. It is S4-S4 sectional drawing of FIG. It is a figure which shows the closed state of the on-off valve 26 of Example 1. FIG. It is a figure which shows the open state of the on-off valve 26 of Example 1. FIG. FIG. 3 is a diagram illustrating a refrigerant flow of Example 1. 3 is a time chart showing the dryout prevention effect of Example 1. FIG. 6 is a cross-sectional view of a motor 105 according to a second embodiment. 6 is a time chart showing the dryout prevention effect of Example 2. FIG. 6 is a cross-sectional view of a motor 105 according to a third embodiment. 10 is a flowchart illustrating a flow of a valve opening / closing control process executed by a controller 45 of the third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 2a, 2b End plate 3 Stator 3 'Stator convex pole part 4 Rotor 5 Motor coil 6 Rotor magnet 7 Motor shaft 8 Motor bearing 9 Flow path 10 Flow path 11 Flow paths 12a, 12b, 12c, 12d, 12e, 12f Cooling Flow path 13 Flow path 14 Flow path 15 Flow path 16 Flow path 17 Flow path 18 Flow path 19 Capacitor 20 Flow path 21 Reservoir tank 22 Air release port 23 Check valve 24 Check valve 25 Check valve 26 On-off valve 27 Check valve 28 Rod 29 Temperature detection coil unit 30 Open / close valve 31 Three-way valve 32 Flow path 43 Temperature sensor 44 Temperature sensor 45 Controller 46 Actuator 102 Tire 105 In-wheel motor 107 Suspension devices 107a and 107b Arm 107c Shock absorber

Claims (12)

A cooling device for cooling the heat generating part with a refrigerant,
A cooling passage that is thermally connected to the heat generating portion and circulates the refrigerant;
A reservoir tank that is arranged vertically above the cooling flow path and stores the refrigerant;
A refrigerant supply channel for supplying a refrigerant from the reservoir tank to the cooling channel;
A refrigerant discharge flow path for returning the refrigerant discharged from the cooling flow path to the reservoir tank;
A condenser that is provided in the refrigerant discharge passage and liquefies the vaporized refrigerant;
A first check valve provided in the refrigerant supply flow path, for preventing a reverse flow of the refrigerant from the cooling flow path to the reservoir tank;
When the temperature of the refrigerant in the cooling channel rises to a set temperature that is equal to or higher than a saturation temperature, refrigerant density lowering means for lowering the density of the refrigerant on the downstream side of the condenser in the refrigerant discharge channel;
A cooling device for a heat generating part. In the cooling device of the heat generating part according to claim 1,
The refrigerant density lowering means is
A low-density refrigerant supply flow that is thermally connected to the heat generating section and communicates the upstream side of the refrigerant check passage with respect to the first check valve and the downstream side of the condenser with respect to the condenser discharge passage. Road,
A normally closed on-off valve provided on the upstream side of the heat generating portion of the low density refrigerant supply flow path;
A valve opening / closing means for opening the opening / closing valve when the temperature of the refrigerant in the cooling channel rises to a set temperature that is a temperature equal to or higher than a saturation temperature;
A cooling device for a heat generating part. In the heat generating unit cooling device according to claim 2,
The low-density refrigerant supply channel is disposed at a position that receives a larger amount of heat from the heat generating unit than the cooling channel. In the cooling device of the heat generating part according to claim 2 or claim 3,
The heat generating part cooling device, wherein the low-density refrigerant supply flow path is disposed near a vertical lowest position of the cooling flow path. In the cooling device of the heat generating part according to any one of claims 2 to 4,
A low density refrigerant supply channel temperature detecting means for detecting the temperature of the low density refrigerant supply channel as a low density refrigerant supply channel temperature;
The heating / cooling device according to claim 1, wherein the valve opening / closing means opens the opening / closing valve when the low-density refrigerant supply flow path temperature is equal to or higher than the set temperature. In the cooling device of the heat generating part according to claim 5,
Cooling channel temperature detecting means for detecting the temperature of the cooling channel as a cooling channel temperature;
When the cooling channel temperature is higher than the set temperature and lower than a heat-resistant temperature setting value that is lower than the heat-resistant temperature of the heat generating portion, the communication position of the low-density refrigerant supply channel with the refrigerant discharge channel Is switched from the downstream side to the upstream side of the condenser, and when the cooling channel temperature is equal to or higher than the heat resistant temperature setting value, the communication position of the low density refrigerant supply channel with the refrigerant discharge channel is Path switching means for switching from the upstream side to the downstream side of the water device;
An apparatus for cooling a heat generating portion. In the cooling device of the heat generating part according to claim 5 or 6,
A plurality of the cooling channels are provided,
The valve opening / closing means opens the opening / closing valve when the temperature of the low-density refrigerant supply channel is equal to or higher than the saturation temperature of the refrigerant in the cooling channel that is located at the uppermost vertical position among the plurality of cooling channels. A cooling device for a heat generating part. In the cooling device of the heat generating part of the heat generating part according to any one of claims 2 to 7,
Provided vertically below the first check valve and upstream of the open / close valve of the low density refrigerant supply flow path to prevent reverse flow of refrigerant from the low density refrigerant supply flow path to the reservoir tank A cooling device for a heat generating part, wherein a second check valve is provided. In the cooling device of the heat generating part according to any one of claims 2 to 8,
The low-density refrigerant supply flow path includes only the open / close valve as a valve body that increases flow path resistance upstream of the open / close valve. In-wheel motor with a built-in motor in the wheel as the drive source of the wheel,
An in-wheel motor comprising the heating unit cooling device according to any one of claims 1 to 9 built in the wheel as a cooling device for cooling the heating unit of the motor. A cooling device for cooling the heat generating part with a refrigerant,
Thermally connecting the heat generating part and the cooling flow path,
A reservoir tank for storing the refrigerant vertically above the cooling flow path;
The refrigerant is supplied from the reservoir tank to the cooling flow path via the refrigerant supply circuit,
A first check valve is interposed between the refrigerant supply flow path and the cooling flow path to prevent the reverse flow of the refrigerant from the cooling flow path to the refrigerant supply circuit;
The refrigerant vaporized in the cooling channel is liquefied with a condenser,
The liquid phase refrigerant is returned to the reservoir tank through the refrigerant discharge circuit,
The cooling device for a heat generating portion, wherein when the temperature of the refrigerant in the cooling channel rises to a set temperature that is a temperature equal to or higher than a saturation temperature, the density of the refrigerant liquidified by the condenser is reduced. Cooling the heat generating part by supplying a refrigerant from a reservoir tank arranged vertically above the cooling flow path to the cooling flow path thermally connected to the heat generating part, After the liquid phase in the condenser, while pushing up to the reservoir tank using the pressure of the refrigerant vaporized in the heat generating part,
When the temperature of the refrigerant in the cooling channel rises to a set temperature that is equal to or higher than the saturation temperature while preventing the refrigerant vaporized in the heat generating part from flowing back to the reservoir tank side, A method for cooling a heat generating portion, characterized by reducing the density of a liquid phase refrigerant.

Images