Cooling unit

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2007-335909 filed on Dec. 27, 2007, the disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a cooling unit having a fan driven by a motor through a gear mechanism, which is, for example, used for generating air for cooling a heat exchanger, such as a radiator of a vehicle.

BACKGROUND OF THE INVENTION

A cooling unit having fans driven by a single motor through a gear-driving mechanism is, for example, described in Japanese Unexamined Patent Application Publication No. 2006-145177. In the described cooling unit, the fans are arranged in parallel with each other behind a core of a heat exchanger. The fans generate air for cooling the core when rotated. The motor has a driving shaft extending parallel to the core. The driving shaft is connected to rotation shafts of the fans through gears, so that the fans are rotated by rotation of the driving shaft.

The described cooling unit further has a fan shroud disposed adjacent to the motor and surrounding outer peripheries of the fans. The fan shroud is formed with through holes, and the driving shaft passes through the through holes. When the fans are rotated by the driving shaft through the gears, air around the motor is conducted to negative pressure sides of the fans through the through holes of the fan shroud while flowing around the motor, and hence the motor is cooled.

SUMMARY OF THE INVENTION

In such a cooling unit, the motor is cooled by air caused by negative pressure of the fans. However, when the amount of air generated by the fans is small, it is difficult to rely on the effect of the negative pressure. That is, because the fans are originally provided for cooling the core, it is difficult to normally and stably supply the motor with air for cooling the motor. If the amount of air for supplied to the motor is increased, it will be difficult to maintain the capacity of cooling the core.

The present invention is made in view of the foregoing matter, and it is an object of the present invention to provide a cooling unit having a fan driven by a motor through a gear, which is capable of stably providing the motor with cooling air.

According to an aspect of the present invention, a cooling unit includes a motor, a driving shaft, a first fan, a second fan, and a fan shroud. The driving shaft extends from the motor and is disposed parallel to a core of a heat exchanger. The first fan is opposed to the core for generating the air for cooling the core. The first fan has a first rotation shaft connected to the driving shaft through a gear to be rotated by the driving shaft. The fan shroud supports the first fan and is configured to conduct the air from the core toward the first fan. The second fan has a second rotation shaft and is configured to generate air for cooling the motor. The second rotation shaft is disposed coaxial with the driving shaft and rotatable with the driving shaft such that the second fan is rotated by the driving shaft when the first fan is rotated.

In such a construction, the second fan is coaxially coupled to the driving shaft for driving the first fan. Therefore, since the second fan is rotated by the driving shaft together with the first fan, a predetermined volume of air can be supplied to the body by the second fan, irrespective of the volume of air supplied to the heat exchanger. The capacity of cooling the motor improves.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and advantages of the present invention will become more apparent from the following detailed description made with reference to the accompanying drawings, in which like parts are designated by like reference numbers and in which:

FIG. 1 is a schematic cross-sectional view of a cooling unit, when viewed from a top, according to a first embodiment of the present invention;

FIG. 2 is a schematic cross-sectional view of a cooling unit according to a first example of a second embodiment of the present invention;

FIG. 3 is a schematic cross-sectional view of a cooling unit according to a second example of the second embodiment;

FIG. 4 is a schematic cross-sectional view of a cooling unit according to a third example of the second embodiment;

FIG. 5 is an end view of a motor of a cooling unit, when viewed along a longitudinal axis of a driving shaft, according to the second embodiment;

FIG. 6 is a schematic cross-sectional view of a cooling unit according to a third embodiment of the present invention;

FIG. 7 is a schematic cross-sectional view of a cooling unit according to a fourth embodiment of the present invention;

FIG. 8 is a schematic side view of a motor of the cooling unit, when viewed along a longitudinal axis of a driving shaft, according to the fourth embodiment;

FIG. 9 is a back view of the motor according to the fourth embodiment;

FIG. 10 is a schematic cross-sectional view of a cooling unit according to a fifth embodiment of the present invention;

FIG. 11 is a schematic cross-sectional view of a joint integrated into a boss part of a motor-cooling fan of a cooling unit according to a sixth embodiment of the present invention;

FIG. 12 is a plan view of an external gear of the joint according to the sixth embodiment;

FIG. 13 is a side view of the external gear, partly including a cross-section, when viewed along an arrow XIII in FIG. 12;

FIG. 14 is a plan view of an internal gear of the joint according to the sixth embodiment; and

FIG. 15 is a side view of the internal gear, partly including a cross-section, when viewed along an arrow XV in FIG. 14.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. Like parts are designated by like reference numbers, and a description thereof is not repeated. In the drawings, an arrow X denotes one direction parallel to a core 2 of a heat exchanger 1. The direction X corresponds to a width direction of a cooling unit, which corresponds to a left and right direction of a vehicle. An arrow Y denotes a direction parallel to axes of fans for cooling the core 2. The direction Y is a frontward direction of the cooling unit, which corresponds to a frontward direction of the vehicle.

First Embodiment

The cooling unit of the present embodiment generally includes first fans 10, a fan shroud 30, a motor device, and a second fan 20. The fans 10 are located to a rear side of the core 2 of the heat exchanger 1 of a vehicle, such as the radiator 1, and mainly generate air passing through the core 2, thereby to cool the core 2. Thus, the fans 10 are hereinafter also referred to as the core-cooling fans 10. The fan shroud 30 is located to the rear side of the core 2 and supports the core-cooling fans 10. The fan shroud 30 has air passage portions having a generally tubular shape for conducting the air passing through the core 2 to the core-cooling fans 10 in a direction opposite to the direction Y.

The core-cooling fans 10 have rotation shafts 13 driven by the motor device. The motor device has a motor 19 for generating a driving force and a driving shaft 17 connected to the rotation shafts 13 of the core-cooling fans 10 through gears 14, 15, 16 for transmitting the driving force to the core-cooling fans 10. The second fan 20 has a rotation shaft 18 that is coaxial with the driving shaft 17 of the motor device. The driving shaft 18 is rotated in accordance with the rotation of the driving shaft 17 so that the second fan 20 generates air for cooling the motor 19. Hereinafter, the second fan 20 is also referred to as the motor-cooling fan 20.

The radiator 1 serves to cool an internal fluid, such as an engine coolant. The radiator 1 generally includes the core 2, first and second tanks 3 and reinforcement members for reinforcing the core 2. The core 2 includes tubes through which the engine coolant flows and fins disposed between the tubes. The first and second tanks 3 are connected to opposite ends of the tubes. The first tank 3 serves to distribute the engine coolant into the tubes and the second tank 3 serves to collect the engine coolant from the tubes.

Further, an inlet pipe that is in communication with a radiator circuit through which the engine coolant circulates is coupled to the first tank 3 for introducing the engine coolant into the first tank 3. An outlet pipe that is in communication with the radiator circuit is coupled to the second tank 3 for introducing the engine coolant, which has passed through the radiator 1, from the second tank 3 into the radiator circuit. The inlet pipe and the outlet pipe extend from a rear side of the first tank 3 toward the engine.

The fan shroud 30 has a generally panel-like member and fixed to the radiator 1. The fan shroud 30 is configured to support and surround the core-cooling fans 10. In the present embodiment, two core-cooling fans 10 are disposed in parallel with each other with respect to the flow of air passing through the core 2. That is, the two core-cooling fans 10 are aligned in the direction X. The two core-cooling fans 10 are driven by the single motor device through a gear mechanism including the gears 14, 15, 16, which will be described later.

Each of the core-cooling fans 10 is an axial fan. The core-cooling fan 10 generally has a boss part 12 fixed to the rotation shaft 13 and blades 11 radially extending from the boss part 12.

The fan shroud 30 has ring portions each having a ring shape. The core-cooling fans 10 are correspondingly disposed in the ring portions of the fan shroud 30. In other words, the ring portions each surround an outer periphery of the blades 11 of the core-cooling fan 10. The air passage portions of the fan shroud 30 extend from an outer edge of the core 2 to the ring portions. The air passage portions define air passages from the rear side of the core 2 to the ring portions. The air passage portions are configured to efficiently conduct air, such as outside air, passing through the core 2 to the ring portions.

Each of the core-cooling fans 10 is disposed downstream of the radiator 1 with respect to the flow of air passing through the core 2. The rotation shaft 13 extends in a direction parallel to the direction Y, such as in a vehicle front and rear direction. The core-cooling fan 10 is rotated as the rotation shaft 13 is rotated by the driving shaft 17, thereby to draw air from an outside of an engine compartment of the vehicle through a front grill part of the vehicle in the vehicle rearward direction toward the engine.

The motor 19 is an electric motor, such as a ferrite d.c. motor. The motor 19 rotates the core-cooling fans 10 through the gear mechanism. The motor 19 is provided with a harness, which is electrically coupled to a battery of the vehicle through a connector or the like. Thus, electric power is supplied to an armature of the motor 19 through the harness.

The motor 19 is disposed at an end of the driving shaft 17 and is projected outside of the radiator 1 with respect to the right and left direction. That is, the motor 19 is offset from a side of the radiator 1 by a predetermined distance in a direction opposite to the direction X. In such a configuration, a thickness of the cooling unit with respect to the front and rear direction, such as the direction Y can be reduced.

The motor 9 is housed in a motor case 31. The motor case 31 has an air inlet opening 32 and an air outlet opening 33. The air inlet opening 32 is located to a side of the tank 3 of the radiator 1 and is open in the frontward direction Y. The air outlet opening 33 is open in the direction X, such as in a longitudinal direction of the driving shaft 17. For example, the motor case 31 can be configured such that a downstream end of the motor case 31 with respect to a flow of air in the motor case 31 constitutes a part of the air passage portion of the fan shroud 30.

The motor case 31 can be made of a resin, such as polypropylene, containing glass fiber, talc and the like so as to have sufficient strength. The motor case 31 can be integrally formed with the fan shroud 30. For example, the motor case 31 can be integrally molded with the fan shroud 30 such as by injection molding using a predetermined mold.

Alternatively, the motor case 31 can be provided as an individual member. In such a case, the motor case 31 and the fan shroud 30 are separately formed, and then the motor case 31 is fixed to the fan shroud 30, another member mounted in the vehicle, or a part of a vehicle body.

The driving shaft 17 extends from the motor 19 in the direction X. The driving shaft 17 is parallel to the core 2 and located to rear sides of the blades 11 of the core-cooling fans 10. The rotation shafts 13 of the core-cooling fans 10 are provided with driven gears 14. A first driving gear 15 is fixed to the driving shaft 17, and engages with the driven gear 14 of the rotation shaft 13 of the core-cooling fan 10, which is located closer to the motor 19 than the other fan 10, such as, a left fan 10 in FIG. 1. A second driving gear 16 is fixed to an end of the driving shaft 17 opposite to the motor 19, and engages with the driven gear 14 of the rotation shaft 13 of the core-cooling fan 10, which is located further from the motor 19 than the other fan 10, such as, a right fan 10 in FIG. 1.

The first driving gear 15 is rotated with the driving shaft 17, and the driven gear 14 is engaged with the first driving gear 15. Thus, the driving force generated by the motor 19 is transmitted to the core-cooling fan 10, which is located closer to the motor 19, through the driving shaft 17, the first driving gear 15, the driven gear 14, and the rotation shaft 13. Likewise, the second driving gear 16 is rotated with the driving shaft 17, and the driven gear 14 is engaged with the second driving gear 16. Thus, the driving force generated by the motor 19 is also transmitted to the core-cooling fan 10, which is located further from the motor 19, through the driving shaft 17, the second driving gear 16, the driven gear 14 and the rotation shaft 13. That is, the two core-cooling fans 10 are rotated by the rotation of the driving shaft 17 through the gears 14, 15, 16.

For example, the first and second driving gears 15, 16 and the driven gears 14 are constructed of a bevel gear, a helical gear, and the like. A gear ratio of the driving gear 15, 16 to the driven gear 14 can be arbitrarily set in a predetermined range. The gear ratio of the first driving gear 15 to the corresponding driven gear 14 and the gear ratio of the second driving gear 16 to the corresponding driven gear 14 can be differentiated such that the volumes of air blown the two core-cooling fans 10 are different. Also, the volume of air for cooling the motor 19 and the volume of air for cooling the radiator 1 can be adjusted to have a suitable relationship by adjusting the gear ratios.

The motor-cooling fan 20 has blades 21 and a boss part 22 including the rotation shaft 18 and supporting the blades 21. The blades 21 radially extend from the boss part 22. The boss part 22 is formed with the rotation shaft 18. The motor-cooling fan 20 is disposed such that the rotation shaft 18 is coaxial with the driving shaft 17. In the present embodiment, the motor-cooling fan 20 is an axial fan. For example, the motor-cooling fan 20 can be a propeller fan.

The rotation shaft 18 of the motor-cooling fan 20 rotates with the rotation of the driving shaft 17. When rotated, the motor-cooling fan 20 causes air to flow from an upstream location of the blades 21 facing the motor 19 in the direction X. As such, the outside air is suctioned into the motor case 31 from the air inlet opening 32, which is open to a side of the tank 3. The suctioned air flows around the motor 19 inside of the motor case 31 and then flows out from the motor case 31 through the air outlet 33 in the direction X. As such, the motor 19 is cooled.

That is, as the driving shaft 17 rotates, the motor-cooling fan 20 and the core-cooling fans 10 are respectively rotated at predetermined gear ratios. Thus, cooling operation of the radiator 1 and the motor 19 are simultaneously performed.

Recently, the number of electric components mounted in an engine compartment of the vehicle has been increased in accordance with improvement of performance of the vehicle. On the other hand, it has been required to reduce the size of vehicle. As such, allowable spaces for mounting the components in the engine compartment tend to be reduced. With this, it is required to reduce the size of the cooling unit as small as possible. In the present embodiment, the dimension of the cooling unit in the front and rear direction can be reduced by the above-described arrangement while improving the capacity of cooling the heat exchanger 1 and the motor 19.

In the present embodiment, the cooling unit includes the two core-cooling fans 10 for cooling the core 2 of the radiator 1, the fan shroud 30, the motor 19, the driving shaft 17 and the motor-cooling fan 20 for cooling the motor 19. The two core-cooling fans 10 are arranged in parallel with each other behind the core 2, and generate the air passing through the core 2 for cooling the core 2. The fan shroud 30 is arranged behind the core 2 and configured to conduct the air passing through the core 2 toward the downstream positions of the core-cooling fans 10. The driving shaft 17 is disposed behind the core 2 and extends parallel to the core 2. The driving shaft 17 is connected to the rotation shafts 13 of the core-cooling fan 10 through the gears 14, 15, 16. The motor-cooling fan 20 is arranged such that the rotation shaft 18 thereof is coaxial with the driving shaft 17. The rotation shafts 13, 18 are rotated by the rotation of the driving shaft 17.

Accordingly, the motor-cooling fan 20 can be driven together with the core-cooling fans 10. The predetermined volume of air is supplied to the motor 19 irrespective of the volume of the air supplied to the radiator 1. Therefore, the cooling unit ensures the predetermined cooling capacity for cooling the motor 19.

Second Embodiment

A second embodiment will now be described with reference to FIGS. 2 to 5. In the present embodiment, the motor 19 is arranged to a rear side of the radiator 1. FIGS. 2 to 4 show first, second third examples of the present embodiment, respectively. FIG. 5 shows the motor device when viewed along the longitudinal direction of the driving shaft 17, such as in the direction X.

In the first example of the present embodiment shown in FIG. 2, the location of the motor 19 is different from that of the first embodiment shown in FIG. 1. Specifically, the motor 19 is located behind the tank 3 of the radiator 1. Also, the motor 19 is located to a side of a vehicle body member 4, such as a member supporting the radiator 1 with respect to the direction X. That is, the motor 19 is overlapped with the radiator 1 with respect to the left and right direction. Other structures are similar to the first embodiments, and thus the similar effects are achieved by those similar structures.

In the first example of the second embodiment, the cooling unit has a motor case 31A and a motor-cooling fan 20A, in place of the motor case 31 and the motor-cooling fan 20 of the first embodiment.

The motor 19 is housed in the motor case 31A. The motor case 31A has an air inlet opening 32A and an air outlet opening 33A. The air inlet opening 32A is provided on a plane perpendicular to a longitudinal axis of the driving shaft 17, and is open in the direction opposite to the direction X. The air inlet opening 32A is widely open in the direction opposite to the direction X such that an axial end of the motor 19 is not covered. For example, the air inlet opening 32A is formed on an entirety of an axial end of the motor case 31A, and has a cross-sectional area that is substantially equal to a cross-sectional area of a main part of the motor case 31A surrounding the motor 19. The air outlet opening 33A is located to the rear side of the tank 3 and in an air-blowing region of the core-cooling fan 10. That is, the air outlet opening 33A is open to a downstream location of the fan 10 behind the tank 3. Further, the air outlet opening 33A is open in the direction X.

The motor case 31A can be configured such that the downstream end thereof constitutes a part of the air passage portion of the fan shroud 30. The motor case 31A can be integrally formed with the fan shroud 30. In such a case, the motor case 31A can be made of a resin, such as polypropylene, containing glass fiber, talc and the like so as to have sufficient strength. Alternatively, the motor case 31A can be an individual member. In such a case, the motor case 31A and the fan shroud 30 are separately formed, and then the motor case 31A can be fixed to the fan shroud 30, another member mounted in the vehicle, or a part of the vehicle body.

The motor-cooling fan 20A has a rotation shaft 18 disposed to be coaxial with the driving shaft 17, similar to the rotation shaft 18 of the first embodiment. In the first example of the present embodiment, the motor 19 is located immediately behind the tank 3 of the radiator 1, and the motor-cooling fan 20A is offset from the tank 3, such as in the direction X. Therefore, a diameter of the motor-cooling fan 20A including blades 21A and a boss part 22A can be increased greater than a diameter of the motor-cooling fan 20 of the first embodiment. For example, the diameter of the motor-cooling fan 20A can be increased to be equal to a dimension of the motor 19 in the front and rear direction. As such, the volume of air generated by the motor-cooling fan 20A is increased, and thus cooling capacity for cooling the motor 19 improves. Other structures of the first example of the second embodiment are similar to the first embodiment, and thus the similar effects are achieved.

In the second example of the present embodiment shown in FIG. 3, the motor 19 is arranged behind the tank 3 of the radiator 1, similar to the first example shown in FIG. 2. The motor 19 and the motor-cooling fan 20A are housed in a motor case 31B, in place of the motor case 31A. The motor case 31B has an air inlet opening 32B at a similar location as the air inlet opening 32A of the motor case 31A. However, the motor case 31B has an air outlet opening 33B at a location different from the air outlet opening 33A of the motor case 31A. Other structures of the second example shown in FIG. 3 are similar to the first embodiment, and thus the similar effects are achieved by those similar structures.

Specifically, the air outlet opening 33B is located more to a front position than the blades 11 of the core-cooling fan 10 with respect to the front and rear direction. The air outlet opening 33B is located in a negative pressure region, that is, in an air suctioning region of the core-cooling fan 10.

In such a construction, a suction force generated by the core-cooling fan 10 is also exerted to the air inside of the motor case 31B. Accordingly, the air blown by the motor-cooling fan 20A can be drawn to the negative pressure region of the core-cooling fan 10 and further conducted to the downstream location of the core-cooling fans 10, with the air passing through the core 2 of the radiator 1 in the rearward direction, by means of the core-cooling fan 10. Because the volume of air flowing around the motor 19 can be further increased by the suction force of the core-cooling fan 10, the cooling capacity for cooling the motor 19 is further improved.

The motor case 31B is configured such that a downstream portion thereof downstream of the motor 19 constitutes a part of the air passage portion of the fan shroud 30. In such a case, the air outlet opening 33B is disposed to open to the inside of the fan shroud 30, particularly, to open to the air passage portion of the fan shroud 30.

The air inlet opening 32B is widely open on a side of the motor case 31B such that the entirety of the axial end of the motor 19 facing the direction opposite to the direction X is not covered. The air outlet opening 33B is located at the downstream portion of the motor case 31B constituting the part of the air passage portion of the fan shroud 30 to allow communication between the inside of the motor case 31B and the negative pressure region of the fan shroud 30.

According to the above configurations of the air inlet opening 32B and the air outlet opening 33B, as the motor-cooling fan 20A is rotated by rotation of the driving shaft 17, the air is suctioned to the inside of the motor case 31B from the air inlet opening 32B. The air flows around the entire circumference of the motor 19 and toward a downstream location of the motor-cooling fan 20A. Further, the air flows in the frontward direction toward the air outlet opening 33B and then flows out from the air outlet opening 33B to the negative pressure region of the core-cooling fan 10.

Particularly, since the air inlet opening 32B is widely open, the air flows to surround the motor 19 inside of the motor case 31B. Inside of the motor case 31B, a part of the air flows along a rear surface of the motor 19. The part of the air further moves to a front side of the motor 19 and flows along a front surface of the motor 19 while flowing toward the air outlet opening 33B. Therefore, the distance of the airflow path within the motor case 31B is increased. An entire outer surface of the motor 19 is efficiently cooled.

The motor case 31B can be integrally formed with the fan shroud 30, similar to the motor case 31 of the first embodiment. In such a case, the motor case 31B is formed of a resin, such as polypropylene, containing glass fiber, talc, and the like so as to have sufficient strength. Alternatively, the motor case 31B and the fan shroud 30 can be separately formed. In such a case, the motor case 31B is fixed to the fan shroud 30, another member mounted in the vehicle, or a part of the vehicle body.

In the third example of the second embodiment shown in FIG. 4, the motor case 31B is modified to a motor case 31C. The motor case 31C has two air outlet openings, such as a first air outlet opening 33C and a second air outlet opening 34C. Other structures are similar to the second example shown in FIG. 3, and thus the similar effects are achieved by those similar structures.

The first air outlet opening 33C is similar to the air outlet opening 33B of the second example shown in FIG. 3. The first air outlet opening 33C is located more to a front position than the blades 11 of the core-cooling fan 10. The first air outlet opening 33C is open to the negative pressure region of the core-cooling fan 10.

The second air outlet opening 34C is located at the downstream portion of the motor case 31C and more to a rear position than the driving shaft 17. Also in the third example, the motor case 31C is configured to constitute a part of the air passage portion of the fan shroud 30. In other words, the first air outlet opening 33C is open to the inside of the fan shroud 30, particularly, open to the air passage portion of the fan shroud 30.

The motor case 31C has an air inlet opening 32C, similar to the air inlet opening 32A of the first example shown in FIG. 2. In the third example, the first and second air outlet openings 33C, 34C can be connected to each other. That is, the first and second air outlet openings 33C, 34C can be provided by a single opening. For example, the first and second air outlet openings 33C, 34C can be provided by at least one opening provided on a side wall of the motor case 31C, the side wall facing in the direction X.

Accordingly, the air suctioned inside of the motor case 31C from the air inlet opening 32C is divided into a first path P1 and a second path P2, the first path P1 passing along a front outer surface of the motor 19 and communicating with the negative pressure region of the core-cooling fan 10 through the first air outlet opening 33C, and the second path P2 passing along a rear outer surface of the motor 19 and communicating with the downstream region of the core-cooling fan 10 through the second air outlet opening 34C.

Therefore, when the volume of air generated by the core-cooling fan 10 is large, the volume of air passing through the first path P1 can be effectively increased by means of the suction force of the core-cooling fan 10. When the volume of air generated by the core-cooling fan 10 is small or an area of the first air outlet opening 33C is small due to the space of the first air outlet opening 33C being limited in accordance with the requirement of the vehicle size reduction, the volume of air cooling the motor 19 can be ensured by the suction force of the motor-cooling fan 20A without largely relying on the suction force of the core-cooling fan 10. In the third example, therefore, the cooling capacity for cooling the motor 19 is stably ensured.

The motor case 31C can be integrally formed with the fan shroud 30, similar to the motor case 31. For example, the motor case 31C can be formed of a resin material, such as polypropylene, containing glass fiber talc and the like so as to have sufficient strength. Alternatively, the motor case 31C and the fan shroud 30 can be separately formed. In such a case, the motor case 31C can be fixed to the fan shroud 30, another member mounted in the vehicle, or a part of the vehicle body.

In the present embodiment, a dimension of the cooling unit with respect to the right and left direction is reduced by the above configuration. Therefore, the dimension of the core 2 in the right and left direction can be increased as much as possible within an allowed space. Accordingly, in addition to the improvement of the motor cooling capacity, the cooling capacity of the radiator 1 can be improved. The cooling unit of the present embodiment will be effectively used in a case where the space for the cooling unit is limited in the right and left direction, but relatively allowed in the front and rear direction.

Further, as shown in FIG. 5, the air suctioned inside of the motor case 31A, 31B, 31C from the air suction opening 32A, 32B, 32C flows through the entire circumference of the motor 19. Therefore, the cooling effect for cooling the motor 19 further improves.

Third Embodiment

A third embodiment of the present invention will now be described with reference to FIG. 6. In the present embodiment, the cooling unit has a centrifugal motor-cooling fan 20B, in place of the axial fan.

Structures other than the motor-cooling fan 20B are similar to the structures of the second example of the second embodiment shown in FIG. 3, and thus the similar effects are achieved by those similar structures.

The motor-cooling fan 20B is a centrifugal fan having a boss part 22B and blades 21B. The boss part 22B is formed with the rotation shaft 18, and the rotation shaft 18 is disposed to be coaxial with the driving shaft 17. The blades 21B are arranged around the boss part 22B across a predetermined distance in the radial direction. The motor-cooling fan 20B has a generally disc-like shape with a predetermined diameter and a predetermined axial dimension. The motor-cooling fan 20B is, for example, a sirocco fan or a turbo fan.

In general, pressure loss is likely to increase in a case where a path of cooling air for cooling the motor 19 is complex, a passage area of the path of the cooling air is small, and/or a space downstream of the fan is small. Even in such a case, the volume of air for cooling the motor 19 is ensured by employing the centrifugal fan.

The rotation shaft 18 of the motor-cooling fan 20B is rotated with the rotation of the driving shaft 17. The air outside of the cooling unit is suctioned in the motor case 31B from the air inlet opening 32B with the rotation of the motor-cooling fan 20B. Inside of the motor case 31B, the air is suctioned to a radially inner space of the motor-cooling fan 20B in the direction X from an air suction port thereof, which is provided at a middle of an axial end of the centrifugal fan 20B and faces the motor 19. The air is then blown out in a centrifugal direction, such as in a radial direction, through the blades 21B. The air is further introduced to the negative pressure region of the core-cooling fan 10 through the air outlet opening 33B.

Accordingly, the air inside of the motor case 31B receives the suction force of the core-cooling fan 10, in addition to the suction force of the motor-cooling fan 20B. As such, the air flowing out of the motor case 31B is introduced to the downstream position of the core-cooling fans 10 with the air passing through the core 2 in the rearward direction. Therefore, even if the pressure loss in the air path for cooling the motor 19 is large, the volume of air for cooling the motor 19 is ensured. Further, the volume of air for cooling the motor 19 is increased by means of the suction force generated by the core-cooling fan 10. As such, the capacity of cooling the motor 19 further improves.

In the present embodiment, even in a case where the space for mounting the cooling unit in the engine compartment is limited in the right and left direction, it is less likely that heated air passing through the core 2 will flow into the motor case 31B since the centrifugal fan 20B can resist to high pressure loss.

Fourth Embodiment

A fourth embodiment of the present invention will now be described with reference to FIGS. 7 to 9. In the present embodiment, the cooling unit is configured such that air generated by the motor-cooling fan 20A passes through a control device 40 and the motor 19 for cooling the control device 40. FIG. 8 shows an internal structure of a motor case 31D for explaining airflow therein, when viewed in the direction X. FIG. 9 shows a back view of the motor case 31D, when viewed in the direction Y. In FIGS. 8 and 9, the direction Z corresponds to an upward direction of the cooling unit, such as a direction perpendicular to a paper surface of FIG. 7.

As shown in FIGS. 7 to 9, the motor 19 and the control device 40 are housed in the motor case 31D. Inside of the motor case 31D, a separation wall 35 is provided between the motor 19 and the control device 40. The control device 40 serves to control an operation of the motor 19. The control device 40 includes a control circuit board, electric components and heat radiation fins 41. The heat radiation fins 41 are exposed to the air passage inside of the motor case 31D for radiating heat. The separation wall 35 is disposed above the motor 19 and under the control device 40.

The motor case 31D is configured such as a first side wall thereof facing the core-cooling fan 10 constitutes a part of the air passage portion of the fan shroud 30. The motor case 31D has an air inlet opening 32D for introducing the air outside of the cooling unit into the motor case 31D, and first and second air outlet openings 33D, 34D for discharging the air from the motor case 31D.

The air inlet opening 32D is provided on an upper portion of a second side wall of the motor case 31D, the second side wall being opposite to the driving shaft 17. The air inlet opening 32D is open to the direction opposite to the direction X. The first air outlet opening 33D is provided in the first side wall, which forms the downstream portion of the motor case 31D. The first air outlet opening 33D is provided to allow communication between the inside of the motor case 31D and the negative pressure region of the core-cooling fan 10, that is, the front area of the core-cooling fan 10. In other words, the first air outlet 33D is provided to open to the inside of the fan shroud 30, particularly, to the air passage portion of the fan shroud 30. The second air outlet opening 34D is located at a rear portion of the motor case 31D. The second air outlet opening 34D is located more to a rear position than the driving shaft 17.

According to the above-described positions of the air inlet opening 32D and the first and second air outlet openings 33D, 34D, the air outside of the motor case 31D is suctioned to the inside of the motor case 31D from the air inlet opening 32D when the motor-cooling fan 20A is operated. Inside of the motor case 31D, the suctioned air flows in the rearward direction. While flowing along the fins 41, which extend in the direction X, the suctioned air cools the control device 40. Then, the air collides with the rear wall of the motor case 31D and thus flows downwardly. The air flows around the motor 19 and further flows toward the downstream location of the motor-cooling fan 20A. Then, the air flows out from the motor case 31D through the first and second air outlet openings 33D, 34D. The air flowing out from the first air outlet opening 33D is blown out to the negative pressure region of the core-cooling fan 10. The air flowing out from the second air outlet opening 34D is blown out to the downstream location of the core-cooling fan 10.

The motor case 31D can be made of a resin material, such as polypropylene, containing glass fiber, talc, and the like so as to have sufficient strength. The motor case 31D can be integrally formed with the fan shroud 30. Alternatively, the motor case 31D can be formed separately from the fan shroud 30. In such a case, the motor case 31D is fixed to the fan shroud 30, another member mounted in the vehicle, or a par of the vehicle body.

In the present embodiment, the air inlet opening 32D is formed at a part of the second side wall of the motor case 31D and is smaller than the air inlet opening 32A, 32B, 32C of the second embodiment. Inside of the motor case 31D, the separation wall 35 is provided to separate a first space 36 where the control device 40 is arranged from a second space 37 where the motor 19 is arranged.

The air suctioned from the air inlet opening 32D first flows in the first space 36. In the first space 36, the air flows around the control device 40. Then, the air enters the second space 37 and flows around the motor 19. Thereafter, the air flows out from the motor case 31D from the first and second air outlet openings 33D, 34D. For example, the separation wall 35 forms an opening for allowing communication between the first space 36 and the second space 37 with the rear wall of the motor case 31D, as shown in FIG. 8.

Since the air inlet opening 32D is formed at a part of the second side wall of the motor case 31D, the velocity of air supplied to the control device 40 is increased. As such, the cooling effect further improves. In addition, the control device 40 is located upstream of the motor 19 with respect to the flow of air. Therefore, the control device 40 can be cooled prior to the motor 19.

Fifth Embodiment

A fifth embodiment of the present invention will now be described with reference to FIG. 10. In the present embodiment, the rotation shaft 18 of the motor-cooling fan 20A is coupled to a rotation shaft 17a of the motor device through a joint 50.

The cooling unit of the present embodiment is similar to the cooling unit of the second embodiment, except that the motor device has a first shaft part 17a and a second shaft part 17b, in place of the driving shaft 17, and the first shaft part 17a is coupled to the rotation shaft 18 of the motor-cooling fan 20A through the joint 50. The effects similar to the second embodiment are achieved by the similar structures.

Here, the first shaft part 17a is directly connected to the motor 19. The joint 50 is not limited to one embodiment, but can have any joint structure capable of coaxially connecting the first shaft part 17a and the rotation shaft 18. For example, the joint 50 can be constructed of a motor-side gear fixed to the first shaft part 17a and a fan-side gear fixed to the rotation shaft 18 of the motor-cooling fan 20A. The motor-side gear and the fan-side gear are engaged with each other, thereby to connect the first shaft part 17a to the rotation shaft 18.

In the present embodiment, the first driving gear 15 and the second driving gear 16 are fixed to the second shaft part 17b. The second shaft part 17b extends parallel to the core 2, similar to the driving shaft 17. The shaft 17b, the rotation shaft 18 of the motor-cooling fan 20A, and the first shaft part 17a are coaxially aligned.

Sixth Embodiment

A sixth embodiment of the present invention will now be described with reference to FIGS. 11 to 15. In the sixth embodiment, the cooling unit has a motor-cooling fan 20C into which a joint 60 is integrated, in place of the joint 50 of the fifth embodiment. Other structures of the cooling unit are similar to the above embodiments.

As shown in FIG. 11, the motor-cooling fan 20C has a boss part 22C and blades 21C radially extending from the boss part 22C. The boss part 22C includes an external gear member 61 and an internal gear member 65. The external gear member 61 is disposed closer to the first shaft part 17a than the internal gear member 65, and is formed with the rotation shaft 18 at its center. The internal gear member 65 is disposed on an outer side of the external gear member 61 and is engaged with the external gear member 61. That is, the boss part 22C is constructed of the external gear member 61 and the internal gear member 65.

As shown in FIGS. 12 and 13, the external gear member 61 includes a disc portion 62 and external teeth 63 projecting from an outer circumference of the disc portion 62 in a radial outward direction. The external teeth 63 are arranged at equal intervals along the circumference of the disc portion 62. For example, the external gear member 61 has eight external teeth 63. The disc portion 62 is integrally connected to the first shaft part 17a at its center.

As shown in FIGS. 14 and 15, the internal gear member 65 includes a cylindrical portion 68 and internal teeth 67. The cylindrical portion 68 has an end wall, and an end of the shaft 17b carrying the first and second driving gears 15, 16 is integrally connected to a center of the end wall. The internal teeth 67 project from an inner surface of the cylindrical portion 68 in a radially inward direction. The internal teeth 67 are arranged at equal intervals in a circumferential direction. For example, the internal gear member 65 has eight internal teeth 67. The blades 21C extends from an outer surface of the cylindrical portion 68.

The internal teeth 67 of the internal gear member 65 are arranged to correspond to grooves between the external teeth 63 of the disc portion 62 of the external gear member 61. The internal teeth 67 are capable of contacting the outer surface of the disc portion 62 between the external teeth 63. The external teeth 63 of the external gear member 61 are arranged to correspond to grooves between the internal teeth 67 of the cylindrical portion 68. The external teeth 63 are capable of contacting the inner surface of the cylindrical portion 68 between the internal teeth 67.

In the present embodiment, the joint 60 is integrated into the motor-cooling fan 20C, particularly, into the boss part 22C. The motor-cooling fan 20C having the joint 60 is formed of a resin material such as by injection molding using a predetermined die. The joint 60 is, for example, made of polypropylene, nylon or the like, containing glass fiber, talc and the like so as to have sufficient strength.

The structure of the shaft and the joint 60 of the present embodiment can be employed in the cooling units of the above-described embodiments.

In the present embodiment, the cooling unit has the joint 60 coaxially connecting the second shaft part 17b, which is connected to the rotation shafts 13 of the core-cooling fans 10 through the gears 14, 15, 16, and the first shaft part17a directly connected to the motor 19. The joint 60 is integrally formed into the motor-cooling fan 20C.

In such a construction, the size of the cooling unit in the longitudinal direction of the shafts 17a, 17b, 18 can be reduced, and axial displacements of the shafts 17a, 17b, 18 are reduced. Further, the entire size of the cooling unit is reduced. In addition, the number of component parts and the number of assembling steps are reduced. Since the joint 60 is integrally formed with the boss part 22C of the motor-cooling fan 20C, arrangement spaces and manufacturing costs are reduced.

Other Embodiments

The various exemplary embodiments of the present invention are described hereinabove. However, the present invention is not limited to the above described exemplary embodiments, but may be implemented in various other ways without departing from the spirit of the invention. Further, the present invention can be implemented by partly combining the above exemplary embodiments in various ways.

In the above embodiments, the fan shroud 30 is made of resin. Alternatively, the fan shroud 30 can be made of a metal. In such a case, the fan shroud 30 can be made by pressing using a die, welding, and the like.

In the above embodiments, the motor-cooling fans 20, 20A, 20B, 20C are disposed downstream of the motor 19 with respect to the flow of air. Alternatively, the motor-cooling fans 20, 20A, 20B, 20C can be disposed upstream of the motor 19.

The number of the core-cooling fans 10 is not limited to two. The fan shroud 30 can be configured to support one core-cooling fan 10 or three or more core-cooling fans 10.

In the above embodiments, each of the core-cooling fans (blowers) 10 includes the single fan with respect to the front and rear direction. However, the core-cooling fan 10 can be constructed of a contra-rotating blower in which two fans are aligned in the front and rear direction and rotated in contra-directions. The contra-rotating blower has high fan efficiency. The rotation shafts of the fans are aligned in the front and rear direction and coupled to the driving shaft 17 through gears.

The fan shroud 30 and the radiator 1 can be fixed in various ways, such as by screws, clips, brackets, and the like.

Additional advantages and modifications will readily occur to those skilled in the art. The invention in its broader term is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described.

Cooling unit

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CPC

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Priority Claims (1)