In-wheel motor cooling structure

Abstract

To provide a cooling structure of an in-wheel motor which can inhibit damage to a passage in which a refrigerant flows.SOLUTION: A cooling structure of an in-wheel motor of the invention is provided within a wheel of a vehicle wheel and comprises: a rotary electric machine which rotates a hub to which the wheel is fixed; a knuckle which rotatably supports the hub and in which multiple passages in which a refrigerant for cooling the rotary electric machine flows are provided; and a pump which circulates the refrigerant between itself and the rotary electric machine through the multiple passages provided within the knuckle.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cooling structure for an in-wheel motor. [Background technology]

[0002] Patent Document 1 discloses a cooling structure for an in-wheel motor that includes a knuckle having a tank portion for storing refrigerant, a pump that pressure-transfers the refrigerant in the tank portion to the motor using the rotational power of the motor, a first piping for sending the refrigerant in the tank portion to the pump, a first flow path for sending the refrigerant pressured from the pump to each component of the motor inside the housing, and a second piping for sending the refrigerant in the housing to the tank portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2009-226973 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the cooling structure for the in-wheel motor disclosed in Patent Document 1, there is a risk that the pipes (flow paths) through which the coolant flows may be damaged by flying stones or the like while the vehicle is traveling.

[0005] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a cooling structure for an in-wheel motor that can suppress damage to the flow path through which the coolant flows. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the cooling structure for an in-wheel motor of the present invention is a cooling structure for an in-wheel motor provided within the wheel of a vehicle, characterized in that it comprises a rotating electric machine that rotates a hub to which the wheel is fixed, a knuckle that rotatably supports the hub and has multiple flow paths provided therein through which a coolant that cools the rotating electric machine flows, and a pump that circulates the coolant between the rotating electric machine and the rotating electric machine via the multiple flow paths provided inside the knuckle.

[0007] As a result, since a flow passage for circulating the coolant between the pump and the rotating electric machine is provided inside the knuckle, damage to the flow passage caused by flying stones or the like can be suppressed.

[0008] In the above, the pump may be driven in conjunction with rotation of the hub.

[0009] This makes it possible to reduce costs by not having to provide a separate drive source dedicated to driving the pump.

[0010] In the above, the pump may have a fixed portion provided on an outer race of a hub bearing interposed between the hub and the knuckle, and a rotating portion provided on the hub.

[0011] This allows the pump to be driven by the rotation difference between the fixed portion and the rotating portion as the hub rotates. Effect of the Invention

[0012] The cooling structure for an in-wheel motor according to the present invention has an effect of suppressing damage to a flow path through which a coolant flows. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of an in-wheel motor according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a cooling structure for an in-wheel motor according to the present invention will be described. However, the present invention is not limited to the embodiment.

[0015] FIG. 1 is a cross-sectional view showing a schematic configuration of an in-wheel motor 1 according to an embodiment. The in-wheel motor 1 according to the embodiment has a stator 11 and a rotor 12, and is provided inside a wheel of a vehicle. The stator 11 has a stator core 111, a stator coil 112, and a stator spindle 113. Stator coils 112 are arranged at equal intervals around the stator 11, which is substantially ring-shaped. The stator coil 112 can generate a rotating magnetic field at a predetermined speed by receiving power supply from a battery. The stator spindle 113 is fixed by a bolt 14 to a knuckle 13 fixed to a suspension arm. The knuckle 13 rotatably supports a hub 16 via a hub bearing 15 in which a plurality of balls are arranged between an outer race (outer ring) 151 and an inner race (inner ring) 152.

[0016] A rotor 12 having a rim portion 121 and a disk portion 122 is rotatably arranged on the outside of the stator 11 at a predetermined interval from the stator 11. In the in-wheel motor 1 according to the embodiment, the rotor 12 has the rim portion 121 and the disk portion 122 as components constituting the wheel of the wheel. The rim portion 121 is located on the radial outside of the stator 11. The disk portion 122 is located on the outside in the axial direction of the stator 11. In this embodiment, the "axial direction" refers to the direction in which the axis AX of the axle 18, which will be described later, extends, unless otherwise specified. A magnet 123 such as a permanent magnet is arranged on the inner periphery side of the rim portion 121 so as to face the stator core 111 of the stator 11, and the rotor 12 rotates relative to the stator 11 as the rotating magnetic field moves. The rotor 12 is fixed to the hub 16 by the hub bolts 17, so that the wheel can be rotated at a predetermined speed by the rotation of the rotor 12.

[0017] The axle 18 corresponds to the rotation shaft of the wheel on which the in-wheel motor 1 is mounted, and is rotatable around the axis line AX. The end on the outer side of the vehicle is fixed to the hub 16 by a locking ring 19.

[0018] The mechanical pump 20 is, for example, an oil pump that pumps a coolant (oil) as a refrigerant, and an inner race 201, which is a fixed part constituting the pump 20, is attached to the outer race 151 of the hub bearing 15, and an outer race 202, which is a rotating part constituting the pump 20, is attached to the hub 16. Then, the outer race 202 rotates in conjunction with the rotation of the hub 16, and the pump 20 is driven by the rotation difference between the inner race 201 and the outer race 202. Note that an electric pump may be used instead of the mechanical pump 20. In this case, the electric pump may be provided on the outer race 151 of the hub bearing 15.

[0019] A first cooling flow passage 114 and a second cooling flow passage 115, which are flow passages through which a coolant flows and extend in the circumferential direction of the stator 11, are provided side by side in the axial direction inside the stator core 111. The first cooling flow passage 114 and the second cooling flow passage 115 are partially in communication with each other inside the stator core 111.

[0020] An outward flow path 131 and a return flow path 132, which are a plurality of flow paths for circulating the coolant between the first cooling flow path 114 and the second cooling flow path 115 in the stator core 111 and the pump 20, are provided in the inside of the knuckle 13 and the inside of the stator 11 (stator core 111 and stator spindle 113) so as to communicate with each other. The connection portions between the knuckle 13 and the stator 11 (stator spindle 113) in the outward flow path 131 and the return flow path 132 are located at positions where no bolts 14 fastening the knuckle 13 and the stator spindle 113 are present in the circumferential direction of the stator 11. In addition, gaskets (not shown) are inserted in the connection portions between the knuckle 13 and the stator 11 (stator spindle 113) in the outward flow path 131 and the return flow path 132 to ensure sealing at the connection portions.

[0021] An inflow end of the outflow passage 131 communicates with a discharge port of the pump 20, and an outflow end of the outflow passage 131 communicates with a first cooling passage 114 in the stator core 111. Moreover, an inflow end of the return passage 132 communicates with a second cooling passage 115 in the stator core 111, and an outflow end of the return passage 132 communicates with an inlet of the pump 20.

[0022] Note that, taking into consideration strength and the like, the knuckle 13 may be enlarged as necessary and provided with internal passages for flowing the coolant, such as the forward passage 131 and the return passage 132. As a method for providing the forward passage 131 and the return passage 132 in the knuckle 13, for example, grooves corresponding to the forward passage 131 and the return passage 132 may be dug in the wall surface of the knuckle 13 by drilling or the like, and then the grooves may be covered with a lid member, or a core may be provided in the portions corresponding to the forward passage 131 and the return passage 132 when the knuckle 13 is produced by casting.

[0023] In the cooling structure of the in-wheel motor 1 according to the embodiment, the pump 20 is driven in response to the rotation of the hub 16, and the coolant discharged from the pump 20 circulates so as to flow through the forward flow path 131, the first cooling flow path 114, the second cooling flow path 115, and the return flow path 132 in that order, before returning to the pump 20, as shown in FIG.

[0024] In the cooling structure of the in-wheel motor 1 according to the embodiment, the coolant is circulated by the pump 20, and the coolant flowing through the first cooling flow passage 114 and the second cooling flow passage 115 removes heat from the stator core 111, thereby cooling the stator core 111 and the stator 11. In addition, the coolant that has received heat from the stator core 111 flows out from the second cooling flow passage 115 to the return flow passage 132, flows through the return flow passage 132, the pump 20, and the outward flow passage 131 in this order, and during the time until it flows back into the first cooling flow passage 114, the heat of the coolant is transferred to the knuckle 13 in the outward flow passage 131 and the return flow passage 132, and is dissipated to the air flowing around the knuckle 13.

[0025] In this way, in the cooling structure of the in-wheel motor 1 of the embodiment, by driving the pump 20 in conjunction with the rotation of the hub 16, the coolant is circulated between the first cooling passage 114 and the second cooling passage 115 and the pump 20 via the forward flow passage 131 and the return flow passage 132, thereby lowering the temperature of the coolant while it flows through the forward flow passage 131 and the return flow passage 132, and the stator core 111 and ultimately the stator 11 can be cooled by the coolant.

[0026] Furthermore, in the cooling structure of the in-wheel motor 1 according to the embodiment, no external piping such as cooling hoses for circulating coolant between the pump 20 and the first cooling passage 114 and the second cooling passage 115 provided in the stator core 111 is required, which solves various problems such as space constraints for mounting the external piping and damage to the external piping due to flying stones, etc. [Explanation of symbols]

[0027] 1 In-wheel motor 11 Stator 12 Rotor 13 Knuckle 14 Volts 15 Hub bearing 16 Hub 17 Hub bolt 18 Axles 19 Locking ring 20 Pump 111 Stator core 112 Stator coil 113 Status Spindle 114 First cooling channel 115 Second cooling channel 121 Rim section 122 Disk section 123 Magnet 131 Outward Flow Path 132 Return flow path 151 Outer Race 152 Inner Race 201 Inner Race 202 Outer Race

Claims

[Claim 1] A cooling structure for an in-wheel motor provided in a wheel of a vehicle, comprising: a rotating electric machine that rotates a hub to which the wheel is fixed; a knuckle that supports the hub rotatably about an axis of an axle having an end fixed to the hub and has a plurality of flow paths formed therein through which a coolant for cooling the rotating electric machine flows; a pump that circulates the coolant between the rotating electric machine and the knuckle through the plurality of flow paths provided inside the knuckle; It is composed of The pump has a fixed portion provided on an outer race of a hub bearing interposed between the hub and the knuckle, and a rotating portion provided on the hub, and the fixed portion and the rotating portion are arranged to face each other in a direction perpendicular to the axis, 13. A cooling structure for an in-wheel motor, comprising: a pump that is driven by a rotational difference between the fixed portion and the rotating portion as the rotating portion rotates in conjunction with the rotation of the hub.

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