Cooling structure for in-wheel motor

Abstract

The present application provides a kind of cooling structure of in-wheel motor, which is the cooling structure of in-wheel motor arranged in the wheel of vehicle wheel.The cooling structure of in-wheel motor is composed of: rotary motor, configured to rotate the wheel hub fixed with wheel;Knuckle, wheel hub is rotatably supported, and multiple flow paths for flowing refrigerant to cool rotary motor are provided in the interior;And pump, configured to circulate refrigerant between rotary motor via multiple flow paths provided in the interior of knuckle.

Description

Technical Field

[0001] This invention relates to a cooling structure for an in-wheel motor. Background Technology

[0002] Japanese Patent Application Publication No. 2009-226973 discloses a cooling structure for an in-wheel motor, which includes: a steering knuckle having a refrigerant storage compartment; a pump that uses the rotational power of the motor to pressurize the refrigerant in the storage compartment to the motor; a first piping for conveying the refrigerant in the storage compartment to the pump; a first flow path for conveying the refrigerant pressurized from the pump to the various components of the motor inside the housing; and a second piping for conveying the refrigerant in the housing to the storage compartment. Summary of the Invention

[0003] The problem that the invention aims to solve

[0004] However, in the cooling structure of the in-wheel motor disclosed in Japanese Patent Application Publication No. 2009-226973, the piping (flow path) that allows the refrigerant to flow may be damaged by flying stones or other objects during vehicle operation.

[0005] The present invention was made in view of the above-mentioned problems, and its object is to provide a cooling structure for an in-wheel motor that can suppress damage to the flow path through which the refrigerant flows.

[0006] Technical solutions for solving the problem

[0007] The cooling structure for the in-wheel motor according to the first aspect of the present invention is a cooling structure for an in-wheel motor disposed inside the wheel, the cooling structure for the in-wheel motor comprising:

[0008] A rotary motor configured to rotate a wheel hub to which the wheel is fixed;

[0009] A steering knuckle, which supports the wheel hub in a rotatable manner, and internally provides multiple flow paths for the refrigerant to cool the rotating motor; and

[0010] The pump is configured to circulate the refrigerant between itself and the rotary motor via the plurality of flow paths disposed inside the steering knuckle.

[0011] With this structure, since a flow path for circulating refrigerant between the pump and the rotary motor is provided in the steering knuckle, damage to the flow path due to flying stones or the like can be suppressed.

[0012] In the in-wheel motor cooling structure described in the first method above, the pump can also be driven as the wheel hub rotates.

[0013] With this structure, no separate dedicated drive source is needed to drive the pump, which correspondingly reduces costs.

[0014] In the in-wheel motor cooling structure described in the first embodiment above, the pump may also have: a fixed part disposed on the outer ring of a hub bearing between the wheel hub and the steering knuckle; and a rotating part disposed on the wheel hub.

[0015] With this structure, the pump can be driven by the rotational difference between the fixed part and the rotating part as the hub rotates.

[0016] The cooling structure of the in-wheel motor involved in this invention has the effect of suppressing damage to the flow path of the refrigerant. Attached Figure Description

[0017] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, wherein like symbols denote like elements, and wherein:

[0018] Figure 1 This is a cross-sectional view showing the schematic structure of the in-wheel motor involved in the embodiment. Detailed Implementation

[0019] The following describes embodiments of the cooling structure for the in-wheel motor according to the present invention. However, the present invention is not limited to these embodiments.

[0020] Figure 1 This is a cross-sectional view showing the schematic structure of the in-wheel motor 1 according to the embodiment. The in-wheel motor 1 according to the embodiment has a stator 11 and a rotor 12, and is disposed inside the wheel. The stator 11 has a stator core 111, stator coils 112, and a stator main shaft 113. In addition, stator coils 112 are arranged at equal intervals around the generally annular stator 11. The stator coils 112 are able to generate a rotating magnetic field at a predetermined speed by receiving power from a battery. The stator main shaft 113 is fixed to a steering knuckle 13 by bolts 14, and the steering knuckle 13 is fixed to a suspension arm. The steering knuckle 13 supports the wheel hub 16 in a rotatable manner via a hub bearing 15 in which a plurality of balls are arranged between an outer ring (outer ring) 151 and an inner ring (inner ring) 152.

[0021] A rotor 12, having a rim portion 121 and a disc portion 122, is rotatably disposed on the outside of the stator 11 at a predetermined interval from the stator 11. Furthermore, in the in-wheel motor 1 according to the embodiment, the rotor 12 has a rim portion 121 and a disc portion 122, which are components of a wheel. The rim portion 121 is located radially outward of the stator 11. The disc portion 122 is located outward in the axial direction of the stator 11. In this embodiment, unless otherwise specified, the "axial direction" refers to the direction in which the axis AX of the axle 18, described later, extends. On the inner circumference of the rim portion 121, permanent magnets or other magnets 123 are disposed opposite to the stator core 111 of the stator 11. As the rotating magnetic field moves, the rotor 12 rotates relative to the stator 11. Since the rotor 12 is fixed to the hub 16 by hub bolts 17, the rotation of the rotor 12 enables the wheel to rotate at a predetermined speed.

[0022] The axle 18 is equivalent to the rotating axle of the wheel that carries the in-wheel motor 1, and can rotate around the axis AX. The outer end of the axle 18 is fixed to the wheel hub 16 by a locking ring 19.

[0023] Mechanical pump 20 is, for example, an oil pump that pumps coolant (oil) as a refrigerant. The inner ring 201, which forms the fixed part of pump 20, is mounted on the outer ring 151 of hub bearing 15, and the outer ring 202, which forms the rotating part of pump 20, is mounted on hub 16. Furthermore, the outer ring 202 rotates as hub 16 rotates, thereby driving pump 20 through the rotational difference between the inner ring 201 and outer ring 202. Alternatively, an electric pump can be used instead of a mechanical pump 20. In this case, the electric pump only needs to be mounted on the outer ring 151 of hub bearing 15.

[0024] Inside the stator core 111, the flow paths for coolant to flow, namely the first cooling flow path 114 and the second cooling flow path 115, extend circumferentially along the stator 11 and are arranged in the axial direction. The first cooling flow path 114 and the second cooling flow path 115 are partially connected to each other within the stator core 111.

[0025] Inside the steering knuckle 13 and the stator 11 (stator core 111 and stator spindle 113), multiple flow paths, namely the outgoing flow path 131 and the returning flow path 132, are interconnected to circulate the coolant between the first cooling flow path 114 and the second cooling flow path 115 within the stator core 111 and the pump 20. The connection between the steering knuckle 13 and the stator 11 (stator spindle 113) in the outgoing flow path 131 and the returning flow path 132 is located where there are no bolts 14 securing the steering knuckle 13 to the stator spindle 113 in the circumferential direction of the stator 11. Furthermore, a gasket (not shown) is inserted at the connection between the steering knuckle 13 and the stator 11 (stator spindle 113) in the outgoing flow path 131 and the returning flow path 132 to ensure a tight seal at the connection point.

[0026] The inflow end of the outflow path 131 is connected to the outlet of the pump 20, and the outflow end of the outflow path 131 is connected to the first cooling path 114 inside the stator core 111. In addition, the inflow end of the return path 132 is connected to the second cooling path 115 inside the stator core 111, and the outflow end of the return path 132 is connected to the inlet of the pump 20.

[0027] Furthermore, considering factors such as strength, the steering knuckle 13 can be enlarged as needed, and internal flow paths such as a outflow path 131 and a return path 132 can be provided to allow coolant to flow. As a method for providing the outflow path 131 and the return path 132 within the steering knuckle 13, for example, grooves corresponding to the outflow path 131 and the return path 132 can be drilled into the wall of the steering knuckle 13 and then covered with a cover member; or, during the casting of the steering knuckle 13, a core can be provided in the portion corresponding to the outflow path 131 and the return path 132.

[0028] In the cooling structure of the in-wheel motor 1 according to the embodiment, it is driven by the pump 20 as the wheel hub 16 rotates, such as Figure 1 As shown, the coolant sprayed from pump 20 circulates by flowing through each flow path in the order of outgoing flow path 131, first cooling flow path 114, second cooling flow path 115 and return flow path 132 and returning to pump 20.

[0029] In the cooling structure of the in-wheel motor 1 according to the embodiment, the coolant is circulated by the pump 20. The coolant flowing through the first cooling flow path 114 and the second cooling flow path 115 carries away heat from the stator core 111, thereby cooling the stator core 111 and even the stator 11. In addition, the coolant that has received heat from the stator core 111 flows out from the second cooling flow path 115 to the return flow path 132, and flows through the return flow path 132, the pump 20, and the outgoing flow path 131 in sequence. Before flowing back into the first cooling flow path 114, the heat of the coolant is transferred to the steering knuckle 13 through the outgoing flow path 131 and the return flow path 132, and dissipates heat to the air flowing around the steering knuckle 13.

[0030] Thus, in the cooling structure of the in-wheel motor 1 according to the embodiment, the pump 20 is driven by the rotation of the hub 16, and the coolant is circulated between the first cooling flow path 114 and the second cooling flow path 115 and the pump 20 via the outgoing flow path 131 and the return flow path 132. This allows the temperature of the coolant to be reduced during the flow of the coolant through the outgoing flow path 131 and the return flow path 132, and the coolant is used to cool the stator core 111 and even the stator 11.

[0031] Furthermore, in the cooling structure of the in-wheel motor 1 according to the embodiment, since there is no need for external piping such as cooling hoses for circulating coolant between the first cooling flow path 114 and the second cooling flow path 115 provided in the stator core 111 and the pump 20, various problems such as the limitation of mounting space for mounting external piping and damage to external piping caused by flying stones can be solved.

Claims

1. A cooling structure for an in-wheel motor, wherein the in-wheel motor is disposed inside a wheel, the cooling structure for the in-wheel motor comprising: A rotary motor configured to rotate a hub to which the wheel is fixed; A steering knuckle supports the wheel hub in a manner rotatable about the axis of an axle whose ends are fixed to the wheel hub, and internally provides multiple flow paths for the refrigerant to cool the rotary motor; and The pump is configured to circulate the refrigerant between itself and the rotary motor via the plurality of flow paths disposed inside the steering knuckle. The pump is configured to be driven as the hub rotates. The pump has: a fixed portion disposed on the outer ring of a hub bearing located between the wheel hub and the steering knuckle; and a rotating portion disposed on the wheel hub. The fixed part and the rotating part are configured to face each other in a direction orthogonal to the axis. The pump rotates along with the hub via the rotating part, thereby being driven by the rotational difference between the fixed part and the rotating part.

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