JP5462641B2 - In-wheel motor - Google Patents

Description

  The present invention relates to an in-wheel motor, and more particularly to an in-wheel motor having an efficient cooling structure.

  An in-wheel motor as a driving device for a vehicle is conventionally known. Since at least a part of the in-wheel motor is disposed in the wheel, it is difficult to sufficiently cool the in-wheel motor disposed in the wheel. For example, Patent Document 1 discloses a cooling structure for an in-wheel motor.

  The in-wheel motor 100 includes a motor 102, a speed reducer 104, a shaft 106, a hub 108, a brake disc 110, a brake caliper 112, a refrigerant pump 114, and a refrigerant pipe 116, as shown in the configuration diagram of FIG. . The motor 102 includes a stator 10, a rotor 12, a motor shaft 14, and a bearing 16, and generates a magnetic field by passing a current through a coil of the stator 10, and accordingly, the motor shaft fixed to the rotor 12. 14 is rotated. The motor shaft 14 is rotatably arranged by a bearing 16. The motor shaft 14 is connected to the shaft 106 via the speed reducer 104. A hub 108 is attached to the shaft 106, and a wheel 120 is fixed to the hub 108 with a bolt or the like. A tire (not shown) is attached to the wheel 120. Thereby, the rotational force of the motor 102 is transmitted as a driving force to the wheel 120 and the tire via the motor shaft 14, the speed reducer 104, the shaft 106, and the hub 108. A brake disc 110 is fixed to the hub 108. By sandwiching the brake disc 110 by the brake caliper 112, the rotation of the hub 108 is limited, and accordingly, the rotation of the wheel 120 and the tire is braked.

  Here, the in-wheel motor 100 is provided with a refrigerant pump 114 and a refrigerant pipe 116. The refrigerant pump 114 pressurizes and discharges the refrigerant (such as lubricating and cooling oil) accumulated in the casing of the motor 102 and flows it into the refrigerant pipe 116. The refrigerant pipe 116 is disposed in the casing of the motor 102, the bearing 16, and the speed reducer 104, and each part of the in-wheel motor 100 is cooled by the refrigerant flowing through the refrigerant pipe 116. The refrigerant used for cooling is returned again into the casing of the motor 102.

  The in-wheel motor 100 is also cooled by being exposed to cooling air generated as the vehicle travels. However, since a part of the in-wheel motor 100 is disposed in a state of being inserted into the wheel 120, it is difficult for cooling air to enter the wheel 120 and the cooling capacity is small.

  In addition, as shown in the configuration diagram of FIG. 11, in order to keep the temperature of the refrigerant lower, the refrigerant pipe 116 of the in-wheel motor 200 is provided with a heat exchanger 118, thereby cooling the refrigerant with cooling air. Structures that increase efficiency are also being considered.

  Furthermore, as shown in the configuration diagram of FIG. 12, a configuration in which a ventilation duct 122 that guides cooling air into the wheel 120 is provided outside the casing of the in-wheel motor 300 is also considered.

JP 2006-304543 A

  However, in the in-wheel motors 100, 200, and 300 as described above, it is difficult to release all the heat that has cooled the interior of the motor with the refrigerant. Even when the heat exchanger 118 is provided outside, it is difficult to effectively use the cooling air generated as the vehicle travels, and the heat exchanger 118 is also enlarged in order to increase the output of the motor 102. There is a need.

  Even when the ventilation duct 122 is provided, the casing wall of the motor 102 on the side facing the cooling air introduction port is cooled, but the internal pressure of the ventilation duct 122 is increased, so that the cooling air is supplied to the wheel 120. The inside of the casing wall and the wheel 120 on the opposite side of the inlet is difficult to cool, and the cooling air cannot be used effectively.

  This invention is made | formed in view of the above problems, and is providing the in-wheel motor which improved the cooling efficiency.

  One aspect of the present invention includes a cylindrical motor housing in which a rotor and a stator are housed, a ventilation port for taking in outside air from the outside of the motor housing toward the peripheral surface of the motor housing, and the motor housing. An inflow comprising a cooling air passage for flowing outside air taken in from the ventilation port with a circumferential surface directed in an axial direction of the motor housing, and an exhaust port disposed on the opposite side of the cooling air passage to the ventilation port. It is a wheel motor.

  Here, it is preferable that the area ratio of the total opening area of the exhaust port to the total opening area of the ventilation port is 5% or less.

Moreover, the cooling air passage path by a plurality of partition walls, it is preferable that it is divided into a plurality of passages.

  Further, it is preferable that the partition wall is arranged in a direction that intersects the direction of the cooling air flowing radially through the cooling air passage with respect to the motor shaft.

  Moreover, it is preferable that the partition wall is arranged with a twist angle θ of 10 ° or more and 20 ° or less with respect to the axial direction of the motor shaft.

  According to the present invention, the cooling efficiency of the in-wheel motor can be improved.

1 is a structural diagram showing a configuration of an in-wheel motor in an embodiment of the present invention. It is a perspective view which shows the structure of the in-wheel motor in embodiment of this invention. It is a figure which shows the relationship between the area ratio of a ventilation port and an exhaust port, and a flow rate increase rate in embodiment of this invention. It is the top view and side view which show an example of arrangement | positioning of the partition wall in embodiment of this invention. It is the top view and side view which show another example of arrangement | positioning of the partition wall in embodiment of this invention. It is the top view and side view which show another example of arrangement | positioning of the partition wall in embodiment of this invention. 1 is a structural diagram showing a configuration of an in-wheel motor in an embodiment of the present invention. It is an enlarged structure figure showing composition of an in-wheel motor in an embodiment of the invention. It is a perspective view which shows the structure of the in-wheel motor in embodiment of this invention. It is structural drawing which shows the structure of the conventional in-wheel motor. It is structural drawing which shows the structure of the conventional in-wheel motor. It is structural drawing which shows the structure of the conventional in-wheel motor.

  The in-wheel motor 400 in the embodiment of the present invention includes a motor 102, a speed reducer 104, a shaft 106, a hub 108, a brake disc 110, a brake caliper 112, a refrigerant pump 114, and refrigerant piping as shown in the structural diagram of FIG. 116 and the ventilation duct 124 are comprised. In the in-wheel motor 400, the motor 102, the speed reducer 104, and the refrigerant pump 114 are stored in the housing 126. In addition, the block diagram of FIG. 1 shows the cross section of the in-wheel motor 400 typically.

  The motor 102 includes the stator 10, the rotor 12, the motor shaft 14, and the bearing 16 as in the prior art. The stator 10 includes a stator coil and a stator core, and generates a magnetic field in the housing 126 by passing a current through the stator coil. For example, when the motor 102 is a three-phase motor, a three-phase magnetic field of U phase, V phase, and W phase is generated from the stator 10. The rotor 12 is disposed so as to be surrounded by the stator 10, and a rotational force is generated in the rotor 12 due to the influence of a field formed by the stator 10. The rotor 12 is fixed to a motor shaft 14 that is rotatably provided by a bearing 16, and the motor shaft 14 is also rotated by the rotational force generated in the rotor 12. The rotation of the motor shaft 14 is transmitted to the speed reducer 104.

  The reduction gear 104 includes a planetary gear, a sun gear, a pinion gear, a ring gear, and a planetary carrier (not shown). The sun gear shaft is rotatably supported and is connected to the motor shaft 14 of the motor 102. The sun gear is coupled to the sun gear shaft. The pinion gear meshes with the sun gear and is rotatably supported. The ring gear is fixed to the housing 126. The planetary carrier is connected to the pinion gear and is splined to the shaft 106. The planetary carrier is supported rotatably.

  When the rotor 12 rotates, the motor shaft 14 also rotates. The rotation of the motor shaft 14 is transmitted to the planetary gear through the sun gear shaft. The planetary gear changes the speed (deceleration) of the rotation received from the sun gear shaft by the sun gear and the pinion gear and transmits it to the planetary carrier. The planetary carrier transmits the rotation transmitted to the planetary gear to the shaft 106.

  A hub 108 is fixed to the distal end portion of the shaft 106. Further, the wheel 120 is fixed to the hub 108 by bolts or the like. A tire (not shown) is attached to the outer periphery of the wheel 120. Thereby, the rotational force of the motor shaft 14 of the motor 102 is transmitted to the wheel 120 and the tire via the speed reducer 104, the shaft 106, and the hub 108.

  The wheel 120 has a cup shape that covers at least part of the outer periphery of the motor 102 or the speed reducer 104 from the hub 108. The wheel 120 includes a disc part 120a and a rim part 120b. A tire (not shown) is attached to the outer edge of the rim portion 120b.

  The housing 126 is formed in a substantially cylindrical shape along the axial direction of the motor shaft 14 of the motor 102.

  The brake disc 110 is a donut plate-like member fixed to the hub 108 so as to protrude from the outer periphery of the hub 108. A brake caliper 112 is disposed at the outer peripheral end of the brake disc 110 so as to sandwich the outer peripheral end of the brake disc 110. By sandwiching the outer peripheral end of the brake disc 110 by the brake caliper 112, the rotation of the wheel 120 and the tire can be braked.

  The in-wheel motor 400 is provided with a cooling structure. As one of the cooling structures, a cooling system using a refrigerant is provided. The refrigerant pump 114 applies pressure to the refrigerant (such as lubricating and cooling oil) accumulated at the bottom of the housing 126 that houses the motor 102 and sends the refrigerant into the refrigerant pipe 116. The refrigerant is supplied to the bearing 16 of the motor 102 and the speed reducer 104 through the refrigerant pipe 116, cools each part of the in-wheel motor 400, and returns to the bottom part of the motor 102. In FIG. 1, the flow of the refrigerant is indicated by black arrows.

  The in-wheel motor 400 is further provided with a cooling system using cooling air. FIG. 2 is a perspective view showing an external structure of the in-wheel motor 400. In FIG. 2, in order to clearly show a cooling system using cooling air, a part (upper right part in the drawing) of the in-wheel motor 400 is cut out to show an internal structure in which the housing 126 is exposed. In FIG. 1, the flow of the cooling air is indicated by white arrows.

  The cooling system using the cooling air of the in-wheel motor 400 has a ventilation duct 124. The ventilation duct 124 includes a ventilation opening 124a and a cooling air passage 124b. The ventilation opening 124a is arranged in the traveling direction of the vehicle to which the in-wheel motor 400 is attached, that is, in the radial direction of the housing 126, and takes in cooling air generated as the vehicle travels from the outside into the cooling air passage 124b. The cooling air passage 124 b is formed by providing an external wall 124 c so as to surround the outer surface of the housing 126 as a gap between the peripheral surface of the housing 126 that houses the motor 102 and the speed reducer 104. That is, the cooling air passage 124 b is formed as a space inside the outer wall 124 c or a space between the inner surface of the outer wall 124 c and the outer surface of the housing 126. The cooling air passage 124b is connected to the ventilation opening 124a. Further, the cooling air passage 124 b is opened toward the hub 108 or the brake disc 110 in the vicinity of the speed reducer 104. Further, an air hole 120c for passing cooling air through the wheel 120 may be provided.

  In the in-wheel motor 400, the outer wall 124c is also provided with a refrigerant passage 124d constituting a part of the refrigerant pipe 116 for circulating the refrigerant. That is, as shown in FIG. 2, the outer wall 124c is provided with an outer peripheral wall 124e and an inner peripheral wall 124f, and at least a part of the refrigerant supplied from the refrigerant pump 114 is passed through the refrigerant passage 124d that is a space therebetween. The Then, at least part of the refrigerant that has passed through the refrigerant passage 124d is supplied to the bearing 16 of the motor 102, the speed reducer 104, and the like, thereby cooling each part of the in-wheel motor 400.

  Furthermore, it is preferable to provide an exhaust port 124g on the outer wall 124c opposite to the ventilation port 124a with respect to the axis of the motor shaft 14. In this case, since the ventilation opening 124a is disposed toward the traveling direction of the vehicle, the exhaust opening 124g is provided toward the opposite direction of the traveling of the vehicle. It is also preferable to provide an exhaust port 124h in the vicinity of the opening of the cooling air passage 124b opened toward the hub 108 or the brake disc 110. The exhaust port 124h is also preferably provided on the outer wall 124c on the opposite side of the ventilation port 124a. Note that at least one of the exhaust ports 124g and 124h may be provided.

  Thereby, the cooling air taken in from the ventilation port 124a can be exhausted from the exhaust port 124g or the exhaust port 124h, and the internal pressure of the ventilation duct 124 can be kept moderate. Therefore, it becomes possible to more effectively take in the cooling air from the ventilation port 124a. Further, by providing the exhaust ports 124g and 124h on the downstream side of the cooling air, it is possible to make it difficult for water, mud and the like to enter the in-wheel motor 400.

  In particular, the total opening area of the exhaust port 124g and the exhaust port 124h is preferably 5% or less of the total opening area of the ventilation port 124a.

  FIG. 3 shows the relationship between the area ratio of the total opening area of the exhaust port 124g and the exhaust port 124h to the total opening area of the ventilation port 124a and the rate of increase in the flow rate of the cooling air flowing from the ventilation port 124a. Compared with the case where the area ratio was 0 (that is, when the exhaust port 124g and the exhaust port 124h were not provided), the flow rate increased by 10% or more when the area ratio was 5% or less. On the other hand, although the effect of providing the exhaust port 124g or the exhaust port 124h is not without, when the area ratio is larger than 5%, the increase in the flow rate is less than 10%.

  In this way, by circulating the refrigerant through the refrigerant passage 124d formed in the outer wall 124c, which is a component of the ventilation duct 124, the refrigerant is cooled by the cooling air taken into the ventilation duct 124, with higher cooling efficiency. The in-wheel motor 400 can be cooled. In particular, by providing the exhaust port 124g or the exhaust port 124h, the flow rate of the cooling air taken from the ventilation port 124a can be increased, and the in-wheel motor 400 can be cooled with higher cooling efficiency.

  Further, in order to determine the positions of the housing 126 and the cooling air passage 124b and increase the mechanical strength, as shown in the perspective view of FIG. 2, the cooling air passage 124b is radially partitioned from the motor shaft 14 on the outer wall 124c. A partition wall 124i may be provided. As described above, by providing the partition wall 124i that partitions the cooling air passage 124b, the mechanical strength of the cooling air passage 124b can be increased, and the cooling efficiency of the refrigerant by the cooling air can be further increased as cooling fins. it can.

  FIG. 4 is a plan view and an internal configuration diagram showing the arrangement of the partition walls 124i. FIG. 4A is a plan view of the in-wheel motor 400 as viewed from above, and FIG. 4B is a side view schematically showing the structure of the ventilation duct 124 provided inside the in-wheel motor 400. . In FIG. 4, the flow of the cooling air is indicated by black arrows. As shown in FIG. 4, in this example, the partition wall 124 i is arranged in parallel along the axial direction of the motor shaft 14 (and the shaft 106).

  FIG. 5 is a plan view and an internal configuration diagram showing an arrangement of another example of the partition wall 124i. FIG. 5A is a plan view of the in-wheel motor 400 as viewed from above, and FIG. 5B is a side view schematically showing the structure of the ventilation duct 124 provided inside the in-wheel motor 400. . In FIG. 5, the flow of the cooling air is indicated by black arrows. As shown in FIG. 5, in this example, the partition wall 124 i is arranged in a state twisted with respect to the axial direction of the motor shaft 14 (and the shaft 106) so as to follow the flow of cooling air in the ventilation duct 124. . At this time, it is preferable that the twist angle θ is 10 ° or more and 20 ° or less with respect to the axial direction of the motor shaft 14 (and the shaft 106). In particular, the twist angle θ is preferably about 15 °.

  Furthermore, a refrigerant passage 124d may be provided inside the partition wall 124i. By passing the refrigerant through the partition walls 124i functioning as cooling fins, the cooling efficiency of the refrigerant by the cooling air can be further increased.

  FIG. 6 is a plan view and an internal configuration diagram showing an arrangement of another example of the partition wall 124i. FIG. 6A is a plan view of the in-wheel motor 400 as viewed from above, and FIG. 6B is a side view schematically showing the structure of the ventilation duct 124 provided inside the in-wheel motor 400. . In FIG. 6, the flow of the cooling air is indicated by black arrows. In the example of FIGS. 4 and 5, the partition wall 124 i is arranged radially from the motor shaft 14 (and the shaft 106). However, in this example, the partition wall 124 i extends along the direction intersecting the flow of the cooling air in the ventilation duct 124. A partition wall 124i is disposed. Since the cooling air taken in from the ventilation opening 124a tends to flow along the traveling direction of the vehicle, the partition wall 124i is disposed along the direction intersecting the traveling direction of the vehicle. At this time, it is more preferable to arrange the partition wall 124 i along a direction substantially perpendicular to the flow of the cooling air in the ventilation duct 124.

  Furthermore, in this example, it is preferable that the partition wall 124i is arranged in a state twisted with respect to the axial direction of the motor shaft 14 (and the shaft 106) so as to follow the flow of cooling air in the ventilation duct 124. Also in this case, it is preferable that the twist angle θ is 10 ° or more and 20 ° or less with respect to the axial direction of the motor shaft 14 (and the shaft 106). In particular, the twist angle θ is preferably about 15 °.

  As described above, by arranging the partition wall 124i, the cooling air can flow more efficiently in the ventilation duct 124, and the cooling efficiency of the in-wheel motor 400 can be increased. In particular, by arranging the partition wall 124i at an angle θ so as to be twisted, the flow resistance of the cooling air in the ventilation duct 124 can be reduced, and an appropriate air flow for heat exchange with the refrigerant can be reduced. The efficiency of cooling utilizing flow formation and metal heat transfer can be improved.

  Furthermore, a refrigerant passage 124d may be provided inside the partition wall 124i. By passing the refrigerant through the partition walls 124i functioning as cooling fins, the cooling efficiency of the refrigerant by the cooling air can be further increased.

  Further, as shown in the structural diagram of FIG. 7, an in-wheel motor 402 may be provided in which a refrigerant passage 124d is provided on a side closer to the housing 126 of the outer wall 124c constituting the cooling air passage 124b. Accordingly, there is an advantage that the housing 126 is cooled more efficiently by the refrigerant when passing through the refrigerant passage 124d.

  Further, as shown in the enlarged structural diagram of FIG. 8, in the in-wheel motors 400 and 402, a refrigerant passage partition wall 124j for partitioning the refrigerant passage 124d into a plurality of passages may be provided. Thereby, the mechanical strength of the refrigerant passage 124d can be increased, and the cooling efficiency by the refrigerant can be increased.

  Moreover, as shown in the perspective view of FIG. 9, you may comprise as the in-wheel motor 404 which made the lower part of the ventilation duct 124 the refrigerant | coolant tank 124k. That is, a part of the ventilation duct 124 is formed as a space independent of the cooling air passage 124b, and this space is used as the refrigerant tank 124k. That is, the formed space and the housing 126 of the motor 102 are connected by a refrigerant passage, and the refrigerant circulated through each part of the in-wheel motor 404 and returned to the housing 126 is stored from the housing 126 into the refrigerant tank 124k. From there, the refrigerant pump 114 is supplied to each part of the in-wheel motor 404 again. Thereby, a refrigerant | coolant and air can be isolate | separated and the circulation of a refrigerant | coolant can be performed more smoothly.

  As mentioned above, although embodiment of this invention was described, you may combine the characteristic part of each embodiment mentioned above suitably.

  10 Stator, 12 Rotor, 14 Motor shaft, 16 Bearing, 100, 200, 300, 400, 402, 404 In-wheel motor, 102 Motor, 104 Reducer, 106 Shaft, 108 Hub, 110 Brake disc, 112 Brake caliper, 114 Refrigerant pump, 116 Refrigerant piping, 118 Heat exchanger, 120 Wheel, 120a Disc part, 120b Rim part, 120c Air hole, 122 Ventilation duct, 124 Ventilation duct, 124a Ventilation opening, 124b Cooling air passage, 124c External wall, 124d Refrigerant Passage, 124e outer peripheral wall, 124f inner peripheral wall, 124g, 124h exhaust port, 124i partition wall, 124j refrigerant passage partition wall, 124k refrigerant tank, 126 housing.

Claims (4)

A cylindrical motor housing containing a rotor and a stator inside;
A ventilation port for taking outside air from the outside of the motor housing toward the peripheral surface of the motor housing;
A cooling air passage for flowing the outside air taken in from the ventilation port with the peripheral surface of the motor housing facing the axial direction of the motor housing;
An exhaust port disposed on the opposite side of the cooling air passage from the ventilation port;
Equipped with a,
An in-wheel motor in which an area ratio of a total opening area of the exhaust port to a total opening area of the ventilation port is 5% or less . The in-wheel motor according to claim 1 ,
The cooling air passing path, in-wheel motors, wherein a by a plurality of partition walls, is divided into a plurality of passages. The in-wheel motor according to claim 2 ,
The in-wheel motor is characterized in that the partition wall is arranged in a direction that intersects the direction of the cooling air flowing radially through the cooling air passage with respect to the motor shaft. The in-wheel motor according to claim 3 ,
The in-wheel motor, wherein the partition wall is disposed with a twist angle θ of 10 ° or more and 20 ° or less with respect to an axial direction of the motor shaft.

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