JP5088258B2 - Power transmission device cooling structure - Google Patents

Description

  The present invention relates to a structure for cooling a power generation source in a power transmission device that is mounted on a vehicle and transmits power generated by the power generation source to drive wheels.

  The electric motor is a power generation source of the vehicle alone or in combination with the internal combustion engine. In this case, generally, the power of the power generation means is transmitted to the drive wheels via a power transmission device that reduces the rotational speed of the internal combustion engine or the electric motor. Patent Document 1 discloses a structure for cooling an electric motor in a hybrid vehicle by flowing cooling oil from the upper part to the lower part of the electric motor.

JP 2004-180376 A (FIG. 2)

  In the technique disclosed in Patent Document 1, since cooling oil flows as it is from the upper part to the lower part of the electric motor, an air layer is generated between the electric motor and the housing, which may reduce the cooling efficiency of the electric motor. is there. This invention is made | formed in view of the above, Comprising: It aims at suppressing the fall of the cooling efficiency of an electric motor in the structure which cools an electric motor with oil.

  In order to solve the above-described problems and achieve the object, a cooling structure for a power transmission device according to the present invention includes an electric motor cooling means provided in a casing for storing an electric motor to cool the electric motor. Oil between the body and the electric motor, and between the casing and the motor in a portion where the motor cooling means is provided, the casing and the motor in a portion other than the portion where the motor cooling means is provided A passage resistance increasing means having a larger oil passage resistance than that between the two is provided.

  As a desirable aspect of the present invention, in the cooling structure of the power transmission device, the flow path resistance increasing means includes a gap formed between the housing and the electric motor in a portion where the electric motor cooling means is provided. It is preferable that the gap is smaller than a gap formed between the casing and the electric motor in a portion other than a portion where the cooling means is provided.

  As a desirable aspect of the present invention, in the cooling structure of the power transmission device, the flow path resistance increasing means is arranged between the casing and the motor in a portion where the motor cooling means is provided, in the direction of the rotation axis of the motor. It is preferable to provide a damming member directed toward the.

  As a desirable aspect of the present invention, in the cooling structure of the power transmission device, it is preferable that the damming member is a protrusion protruding from the housing toward the electric motor.

  As a desirable aspect of the present invention, in the cooling structure of the power transmission device, the motor cooling means has a cooling medium passage through which a cooling medium flows, and the dam member is more than the range in which the cooling medium passage is provided. It is preferable to provide on the downstream side in the oil flow direction.

  As a desirable aspect of the present invention, in the cooling structure of the power transmission device, a gap formed between the casing and the motor in a portion where the motor cooling means is provided is parallel to the rotating shaft of the motor. The opening in the direction is preferably provided with a sealing means.

  The present invention can suppress a reduction in cooling efficiency of an electric motor in a structure in which the electric motor is cooled with oil.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following description. In addition, constituent elements in the following description include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range.

  The present embodiment includes an electric motor cooling unit that is provided in the casing of the power transmission device and cools the electric motor stored in the casing, and includes the casing of the power transmission device and the electric motor stored in the casing. In the portion where the motor cooling means is provided, the passage resistance increasing means is provided in the portion formed between the casing and the motor in the portion where the motor cooling means is provided, and the casing other than the portion where the cooling means is provided It is characterized in that the flow path resistance is larger than between the motor and the motor. That is, the present embodiment is characterized in that the oil is less likely to flow between the housing and the motor in the portion where the motor cooling means is provided than between the housing and the motor in the portion other than the portion where the cooling means is provided. There is.

  FIG. 1 is a schematic diagram illustrating a vehicle including a power transmission device according to the present embodiment. FIG. 2 is a schematic diagram of the power transmission device according to the present embodiment. The vehicle 100 on which the power transmission device 1 is mounted is a so-called hybrid vehicle that uses the internal combustion engine 10, the second electric motor 12, and the first electric motor 11 as power generation means. The internal combustion engine 10, the second electric motor 12, and the first electric motor 11 mounted on the vehicle 100 are power generation means of the vehicle 100. The power generated by the internal combustion engine 10 and the second electric motor 12 is transmitted to the drive shafts 8L and 8R of the vehicle 100 by the power transmission device 1 to drive the drive wheels 9L and 9R attached to the drive shafts 8L and 8R. Then, the vehicle 100 is caused to travel. An arrow A direction shown in FIG. 1 indicates a forward direction among the directions in which the vehicle 100 travels (the same applies hereinafter). The internal combustion engine 10 is controlled by an engine ECU (Electronic Control Unit) 21, and the first electric motor 11 and the second electric motor 12 are controlled by the electric motor ECU 22 via the inverter 23. The engine ECU 21 and the electric motor ECU 22 are controlled by the main ECU 20.

  The power transmission device 1 includes a housing 2, a planetary gear device 3, a counter gear 4, and a differential gear 6. The casing 2 includes a planetary gear unit 3, a counter gear 4, and a differential gear 6 that are components of the power transmission device 1, and a second motor 12 and a first motor 11 that are power generation units. Placed in. As shown in FIG. 2, the housing 2 includes a first housing 2A in which the first electric motor 11 is arranged and a second housing 2B in which the second electric motor 12 is arranged. A second motor cover 2C is attached to the second housing 2B. The second electric motor 12 and the first electric motor 11 serve as electric motors that generate power by electric power supplied via an inverter 23 from an electric power source (for example, a secondary battery or a capacitor) 24 having both an electric power supply function and an electric storage function. It has a function (power running function) and a function (regenerative function) as a generator that converts mechanical energy into electrical energy.

  The power generated by the internal combustion engine 10 and the power generated by the first electric motor 11 are respectively input to the planetary gear unit 3. In this embodiment, the output shaft (internal combustion engine output shaft) 10S of the internal combustion engine 10 is connected to the carrier of the planetary gear device 3, and the output shaft (first motor output shaft) 11S of the first electric motor 11 is connected to the planetary gear device 3. Connected to sun gear. The sun gear, the carrier, and the ring gear of the planetary gear device 3 have the same rotation axis. Therefore, the rotation shaft (internal combustion engine rotation shaft) Ze of the internal combustion engine 10 and the rotation shaft (first motor rotation shaft) Zm1 of the first electric motor 11 are the same. The internal combustion engine rotation axis Ze and the first motor rotation axis Zm1 are the same as the rotation axis Zp of the planetary gear unit 3. Since the first electric motor 11 is disposed between the planetary gear device 3 and the internal combustion engine 10, the internal combustion engine output shaft 10S passes through the hollow first electric motor rotation shaft 11S and serves as a carrier for the planetary gear device 3. Connected.

  A pinion gear 7 is attached to the output shaft (second motor output shaft) 12S of the second electric motor 12, and meshes with an outer peripheral gear formed on the outer peripheral portion of the annular member constituting the ring gear of the planetary gear device 3. As a result, the power generated by the second electric motor 12 is input to the planetary gear unit 3. The rotation shaft (second motor rotation shaft) of the second electric motor 12 is Zm2. The power generated by the internal combustion engine 10, the power generated by the first motor 11, and the power generated by the second motor 12 are combined by the planetary gear device 3 and output from the outer peripheral gear of the planetary gear device 3, It is transmitted to the counter gear 4 that meshes with the outer peripheral gear. Thus, the planetary gear device 3 functions as a power split mechanism.

  The counter gear 4 meshes with a first counter gear 4I that meshes with the outer peripheral gear of the planetary gear device 3 and a ring gear (differing gear) 6R of the differential gear 6, and is connected to the first counter gear 4I to be connected to the first counter gear 4I. 4I and a second counter gear 4T having a common rotating shaft. The rotation axis of the counter gear 4 is Zc.

  In the present embodiment, the number of teeth of the second counter gear 4T is smaller than the number of teeth of the first counter gear 4I. The differential gear 6 is attached with the drive shafts 8L and 8R of the vehicle 100, respectively. The power of the internal combustion engine 10 and the second electric motor 12 input from the planetary gear unit 3 to the first counter gear 4I of the counter gear 4 is input from the second counter gear 4T to the differential gear 6. This power is output from the differential gear 6 to the drive shafts 8L and 8R to drive the drive wheels 9L and 9R.

  FIG. 3 is an explanatory diagram illustrating a cooling structure of the power transmission device according to the present embodiment. FIG. 4 is an enlarged view showing a cooling structure of the power transmission device according to this embodiment. The diagram shown on the left side of FIG. 3 represents a side view of the diagram shown on the right side. A power transmission device cooling structure (hereinafter referred to as a cooling structure as needed) 200 is stored in a second housing 2B of the power transmission device 1 shown in FIGS. The motor 12 is cooled.

  An electric motor cooling means 50 is provided in the second housing 2B outside the second electric motor 12. In this embodiment, the motor cooling means 50 is provided integrally with the second casing 2B in a part of the second casing 2B, but the motor cooling means 50 is configured separately from the second casing 2B. You may attach to the 2nd housing | casing 2B.

  The electric motor cooling means 50 is of a liquid cooling type that cools the second electric motor 12 with a cooling medium (for example, cooling water of the internal combustion engine 10 shown in FIG. 1). The motor cooling means 50 has a space filled with a cooling medium, and includes a cooling medium passage 54 formed by partitioning the space with a plate-shaped partition member 53. The cooling medium flows in the cooling medium passage 54 in the direction of the arrow W, and cools the second electric motor 12 in the process.

  As shown in FIG. 3, a gap is formed between the second electric motor 12 and the second housing 2B. During operation of the vehicle 100 (particularly during driving of the second electric motor 12), oil is supplied to the gap from the first oil supply port 51A and the second oil supply port 51B provided above the second electric motor 12. . This oil is used to lubricate the planetary gear unit 3 and the differential gear 6 constituting the power transmission device 1 and the sliding parts (for example, bearings) of the power transmission device 1 and to cool the second motor 12 and the first motor 11. Used.

  The oil supplied from the first oil supply port 51A flows through the gap between the second motor 12 and the second housing 2B in the part where the motor cooling means 50 is provided (arrow LA in FIG. 3), and the second motor 12 flows out from an oil recovery port 52 formed below the oil. The oil supplied from the second oil supply port 51B flows through the gap between the second electric motor 12 and the second housing 2B in the part where the electric motor cooling means 50 is not provided (arrow LB in FIG. 3). It flows out from an oil recovery port 52 formed below the electric motor 12. Thus, during operation of the vehicle 100, oil exists between the second housing 2B and the second electric motor 12.

  The oil flowing out from the oil recovery port 52 returns to the space where the planetary gear device 3 and the differential gear 6 shown in FIGS. 1 and 2 are arranged. Here, the downward direction refers to the direction of gravity (vertical direction, the direction indicated by the arrow G in FIG. 3) in a state where the power transmission device 1 is mounted on the vehicle 100 and the vehicle 100 is stopped on a horizontal road surface. ) Side. Further, upward refers to the side opposite to the direction of action of gravity when the power transmission device 1 is mounted on the vehicle 100 and the vehicle 100 is stopped on a horizontal road surface.

  By making oil exist in the gap (cooling means side gap) between the second housing 2B and the second electric motor 12 in the portion where the motor cooling means 50 is provided, the air layer in the cooling means side gap is filled, (2) The thermal resistance from the electric motor 12 to the electric motor cooling means 50 is reduced. However, since oil flows from the upper side to the lower side of the second electric motor 12 due to the action of gravity, an air layer is easily generated in the gap on the cooling means side, and the thermal resistance from the second electric motor 12 to the electric motor cooling means 50 is high. Prone. As a result, the cooling efficiency of the second electric motor 12 may be reduced.

  Further, when T1 <T2 <T3, where T1 is the temperature of the cooling medium flowing through the motor cooling means 50, T2 is the temperature of the oil existing in the cooling means side gap, and T3 is the temperature of the second motor 12. The second electric motor 12 can be cooled by the cooling medium flowing through the electric motor cooling means 50. However, when T1 <T3 <T2 depending on the driving conditions of the vehicle 100, the heat of the oil moves to the second electric motor 12 and the cooling medium, and thus the second electric motor 12 cannot be cooled.

  In order to cool the second electric motor 12, it is necessary to satisfy T1 <T2 <T3. Therefore, it is necessary to lower the temperature of the oil existing in the cooling means side gap. However, since the amount of oil used in the power transmission device 1 is large, it takes time to lower the temperature of the whole oil by an oil cooling means such as an oil cooler. In this embodiment, oil is retained in the cooling means side gap, so that an air layer is hardly generated in the cooling means side gap. Accordingly, the heat of the oil is easily transmitted to the electric motor cooling means 50, and the temperature of the oil can be lowered, so that a decrease in the cooling efficiency of the second electric motor 12 can be suppressed.

  Further, since the amount of oil staying in the cooling means side gap is very small compared to the total amount of oil used in the power transmission device 1, the temperature T2 of the oil staying in the cooling means side gap is quickly determined by the motor cooling means 50. It becomes about the same as the temperature T1 of the cooling medium. That is, T1≈T2 <T3. As a result, even when the oil temperature T2 is higher than the temperature T3 of the second electric motor 12, the second electric motor 12 can be cooled.

  In order to make oil stay in the cooling means side gap, in this embodiment, the cooling means side gap is a gap between the second electric motor 12 and the second housing 2B in a portion where the electric motor cooling means 50 is not provided (non-cooling). Make the oil difficult to flow into the gap on the means side. That is, the cooling means side gap has a larger flow resistance than the non-cooling means side gap. More specifically, the flow path resistance increasing means is provided in the cooling means side gap by making the size tc1 of the cooling means side gap smaller than the non-cooling means side gap tc2. For this reason, a projecting portion 60 that projects toward the outer surface 12W of the second electric motor 12 is formed on the inner surface 2W of the second housing 2B at a portion where the electric motor cooling means 50 is provided (FIG. 4). The overhang portion 60 is a channel resistance increasing means, and extends over the entire area of the second electric motor 12 in the direction parallel to the second electric motor rotation axis Zm2 toward the second electric motor rotation axis Zm2.

  As a result, tc1 <tc2, and the cooling means side gap is less likely to flow oil than the non-cooling means side gap. As a result, the oil stays in the cooling unit side gap, so that the heat of the oil is easily transmitted to the electric motor cooling unit 50 and the temperature of the oil can be lowered, so that the cooling efficiency of the second electric motor 12 is reduced. Can be suppressed.

  The overhanging portion 60 formed in the cooling means side gap is formed, for example, by cutting the second housing 2B. When the overhang portion 60 is formed in the cooling means side gap, the second casing 2B is manufactured because the material scraped off and discarded is reduced as compared with the case of cutting the entire circumference of the second electric motor 12. The cost for doing so can be reduced.

  FIG. 5 is a cross-sectional view of the cooling structure of the power transmission device according to this embodiment. 6 and 7 are cross-sectional views showing a cooling structure of a power transmission device according to a modification of the present embodiment. FIGS. 5-7 is a XX arrow directional view of FIG. 3, and has shown the state which cut | disconnected the cooling structure in the plane which passes along 2nd motor rotating shaft Zm2. As shown in FIG. 5, the second electric motor 12 is attached to the second housing 2 </ b> B, and then the second electric motor cover (electric motor cover) 2 </ b> C is attached. In the second electric motor 12, a stator 12ST is disposed around the rotor 12C. A gap formed between the stator 12ST of the second motor 12 and the second housing 2B is a cooling means side gap, and the oil L stays there.

  For example, if the thickness of the second motor cover 2C is reduced for weight reduction or the like, the second motor cover 2C has a shape as indicated by a dotted line Q in FIG. In this case, a cooling means side gap is opened on the second motor cover 2C side. The opening of the cooling means side clearance is formed in a direction parallel to the second motor rotation axis Zm2. The amount of oil L supplied from the first oil supply port 51A shown in FIG. 3 to the cooling means side gap flows into the second electric motor cover 2C from the opening and stays in the cooling means side gap. May decrease.

  In the cooling structure 200a shown in FIG. 5, a sealing means is provided in the opening of the cooling means side gap. In the cooling structure 200a, the thick portion 2CS obtained by increasing the thickness of the second motor cover 2C in the portion where the opening is formed is used as the sealing means. Since the opening is closed by the thick portion 2CS, the outflow of the oil L from the opening into the second electric motor cover 2C is reduced, and the amount of the oil L staying in the cooling means side gap is reduced. Can be suppressed. As a result, the generation of an air layer in the cooling means side gap is suppressed and the temperature of the oil L can be lowered, so that the second electric motor 12 can be efficiently cooled.

  In the cooling structure 200b shown in FIG. 6, a filler (for example, resin) 12P is disposed between the stator 12ST of the second electric motor 12 and the second electric motor cover 2C, and the opening is closed. Thereby, the effect of improving the cooling efficiency of the second motor 12 by the action of the filler 12P that reduces the outflow of the oil L from the opening into the second motor cover 2C can be obtained. Further, since the stator 12ST and the second motor cover 2C are thermally connected via the filler 12P, the heat of the second motor 12 is transmitted through the filler 12P and radiated from the second motor cover 2C. Can also be obtained. Thereby, the 2nd electric motor 12 can be cooled more efficiently.

  In the cooling structure 200c shown in FIG. 7, a flange 12F is provided on the annular member 12R fitted into the stator 12ST of the second electric motor 12, and the opening is closed by the flange 12F. At this time, it is preferable that the flange 12F and the second motor cover 2C are configured to be thermally connected. In this cooling structure 200c, the effect of improving the cooling efficiency of the second electric motor 12 by the action of the flange 12F that reduces the outflow of the oil L from the opening into the second electric motor cover 2C is obtained. Further, by thermally connecting the stator 12ST and the second motor cover 2C via the flange 12F, the effect that the heat of the second motor 12 is transmitted from the second motor cover 2C through the flange 12F is also obtained. It is done. Thereby, the 2nd electric motor 12 can be cooled more efficiently. In particular, since the annular member 12R and the flange 12F are metal materials having excellent thermal conductivity, the heat of the second motor 12 can be more efficiently transmitted to the second motor cover 2C.

  By providing the above-described configuration for closing the opening of the cooling means side gap, the oil can be reliably retained in the cooling means side gap, which is preferable because the cooling efficiency of the oil and the second electric motor 12 is improved. However, oil is retained in the cooling means side gap even if only the structure in which the flow path resistance of the cooling means side gap is larger than the flow resistance of the non-cooling means side gap is not provided. By this action, the cooling efficiency of the oil and the second electric motor 12 can be improved. As described above, in this embodiment and the modification thereof, it is only necessary to have a configuration in which at least the flow path resistance of the cooling means side gap is larger than the flow path resistance of the non-cooling means side gap. Moreover, the structure which closes the opening part of the cooling device side clearance mentioned above is applicable also to the modification demonstrated below.

  8 and 9 are enlarged views showing a cooling structure of the power transmission device according to a modification of the present embodiment. The cooling structure 200d shown in FIG. 8 sets the size tc1 of the cooling means side gap toward the flow direction of oil flowing into the cooling means side gap from the first oil supply port 51A (the direction indicated by the arrow LA in FIG. 8). The feature is that it is gradually reduced. In this cooling structure 200d, the cooling means side gap is more than the non-cooling means side gap from the position where the size tc1 of the cooling means side gap starts to decrease to the position where the size tc1 of the cooling means side gap becomes the smallest. Get smaller.

  In order to gradually reduce the size tc1 of the cooling means side gap, an overhanging portion that protrudes toward the outer surface 12W of the second electric motor 12 on the inner surface 2W of the second housing 2B on the portion where the electric motor cooling means 50 is provided. 61 is formed (FIG. 4). The overhanging portion 61 is a flow path resistance increasing unit, and is configured to gradually approach the outer surface 12W of the second electric motor 12 in the oil flowing direction. Further, the overhang portion 61 extends over the entire area of the second electric motor 12 in the direction parallel to the second electric motor rotation axis Zm2 toward the second electric motor rotation axis Zm2. As a result, oil is less likely to flow in the cooling means side gap than in the non-cooling means side gap, so that oil stays in the cooling means side gap. As a result, the heat of the oil is easily transmitted to the electric motor cooling means 50, and the temperature of the oil can be reduced, so that a decrease in the cooling efficiency of the second electric motor 12 can be suppressed.

  In heat conduction, generally, the larger the temperature difference, the larger the heat conduction amount, and the smaller the temperature difference, the smaller the heat conduction amount. In the relationship between the oil and the cooling medium of the electric motor cooling means 50, the oil is cooled earlier as the temperature difference between the oil and the cooling medium is larger. The high-temperature oil that has flowed into the cooling means side gap of the cooling structure 200d has a large temperature difference from the cooling medium, and thus is quickly cooled even if the amount is large, that is, even if the cooling means side gap is large. On the other hand, as the oil flows, the size of the cooling means side gap decreases, so the amount of oil passing through the cooling means side gap decreases, and even if the temperature difference between the oil and the cooling medium decreases, it is efficient. Heat exchange. In this way, the cooling structure 200d can uniformly and efficiently reduce the temperature of the oil while ensuring the amount of oil for cooling. As a result, the second electric motor 12 can be cooled more efficiently.

  The cooling structure 200e shown in FIG. 9 is characterized in that a damming member 62 is provided in the gap on the cooling means side. The dam member 62 is a flow path resistance increasing means, and is a protrusion protruding from the inner surface 2W of the second housing 2B toward the outer surface 12W of the second electric motor 12, and an end thereof is connected to the outer surface 12W of the second electric motor 12. Configured to touch. The dam member 62 may be provided with a protrusion on the outer surface 12W of the second electric motor 12 so that the protrusion protrudes toward the inner surface of the second housing 2B.

  The dam member 62 extends over the entire area of the second motor 12 in the direction parallel to the second motor rotation axis Zm2 toward the second motor rotation axis Zm2. Moreover, it is preferable that the dam member 62 is provided on the downstream side in the oil flowing direction, rather than the range where the cooling medium passage 54 of the electric motor cooling means 50 is provided (the range indicated by the double diagonal lines in FIG. 9). Thus, it is preferable to provide the damming member 62 in the gap on the cooling means side avoiding the range where the motor cooling means 50 is provided. Accordingly, since the heat of the oil staying in the cooling means side gap can be transmitted to the cooling medium using the entire portion where the cooling medium passage 54 is formed, the temperature of the oil is efficiently reduced, and the second The electric motor 12 can be cooled.

  In this way, by forming the damming member 62 in the cooling means side gap, oil is less likely to flow in the cooling means side gap than in the non-cooling means side gap, so that oil stays in the cooling means side gap. To come. As a result, the heat of the oil is easily transmitted to the electric motor cooling means 50, and the temperature of the oil can be reduced, so that a decrease in the cooling efficiency of the second electric motor 12 can be suppressed. Further, since only the clogging member 62 needs to be processed, it is possible to reduce processing labor and discarded materials.

  As described above, in this embodiment and the modified example thereof, oil exists between the casing of the power transmission device and the electric motor stored in the casing, and the cooling means side gap is more than the non-cooling means side gap. Makes oil difficult to flow. As a result, oil can be retained in the cooling means side gap, so that an air layer is hardly generated in the cooling means side gap. As a result, the heat of the oil is easily transmitted to the electric motor cooling means, and the temperature of the oil can be reduced, so that a reduction in the cooling efficiency of the electric motor can be suppressed.

  As described above, the cooling structure of the power transmission device according to the present invention is useful for a structure that cools the electric motor disposed in the casing of the power transmission device with oil, and particularly suppresses a decrease in the cooling efficiency of the electric motor. Suitable for that.

It is a schematic diagram which shows a vehicle provided with the power transmission device which concerns on a present Example. It is a schematic diagram of the power transmission device according to the present embodiment. It is explanatory drawing which shows the cooling structure of the power transmission device which concerns on a present Example. It is an enlarged view which shows the cooling structure of the power transmission device which concerns on a present Example. It is sectional drawing of the cooling structure of the power transmission device which concerns on a present Example. It is sectional drawing which shows the cooling structure of the power transmission device which concerns on the modification of a present Example. It is sectional drawing which shows the cooling structure of the power transmission device which concerns on the modification of a present Example. It is an enlarged view which shows the cooling structure of the power transmission device which concerns on the modification of a present Example. It is an enlarged view which shows the cooling structure of the power transmission device which concerns on the modification of a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power transmission device 2 Case 2C 2nd motor cover 2CS Thick part 2W Inner surface 2A 1st case 2B 2nd case 3 Planetary gear device 4 Counter gear 6 Differential gear 7 Pinion gear 8L, 8R Drive shaft 9L, 9R Drive wheel DESCRIPTION OF SYMBOLS 10 Internal combustion engine 11 1st electric motor 12 2nd electric motor 12C rotor 12F flange 12ST stator 12R annular member 12P filler 12W outer surface 50 Electric motor cooling means 51A 1st oil supply port 51B 2nd oil supply port 52 Oil recovery port 53 Partition member 54 Cooling Medium passage 60, 61 Overhang portion 62 Damping member 100 Vehicle 200, 200a, 200b, 200c, 200d, 200e Cooling structure

Claims (6)

Electric motor cooling means provided in a housing for storing the electric motor to cool the electric motor;
Oil is present between the casing and the electric motor, and between the casing and the motor in a portion where the electric motor cooling means is provided, the casing in a portion other than the portion where the electric motor cooling means is provided A cooling structure for a power transmission device, characterized in that a flow path resistance increasing means having a flow path resistance of the oil larger than that between the motor and the motor is provided.   The flow path resistance increasing means has a gap formed between the casing and the motor in a portion where the motor cooling means is provided, between the casing and the motor in a portion other than the portion where the cooling means is provided. The cooling structure for a power transmission device according to claim 1, wherein the cooling structure is smaller than a gap formed in the power transmission device.   The flow path resistance increasing means is provided with a damming member provided in the direction of the rotation axis of the electric motor between the casing and the electric motor in a portion where the electric motor cooling means is provided. Cooling structure of power transmission device.   The cooling structure for a power transmission device according to claim 3, wherein the damming member is a protrusion protruding from the housing toward the electric motor. The motor cooling means has a cooling medium passage through which a cooling medium flows,
5. The cooling structure for a power transmission device according to claim 3, wherein the dam member is provided on a downstream side in a direction in which the oil flows than a range in which the cooling medium passage is provided.   A sealing means is provided in an opening in a direction parallel to the rotation axis of the motor in a gap formed between the casing and the motor in a portion where the motor cooling means is provided. The cooling structure of the power transmission device according to any one of claims 1 to 5.

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