CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 10-2020-0010427, filed on Jan. 29, 2020, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

BACKGROUND

1. Field

This disclosure relates to a motor housing assembly for cooling a motor assembly.

2. Background

A motor is a power device that applies a current to rotate a rotor. The rotor rotates through electromagnetic interaction with a stator. For this, a coil is wound on the stator and the rotor includes a permanent magnet (or vice versa). In response to the current being applied, a magnetic field may be formed around the coil. The magnetic field may lead to electromagnetic interaction between the coil and the permanent magnet so that a rotational force for driving mechanical load is assigned to the rotor.

The motor is used in various fields. Recently, with increasing necessity and demand for hybrid vehicles and electric vehicles, interests in motors required for the vehicles are also increasing.

A vehicle motor may be required to rotate at high speed and often exposed to a situation in which it is driven for a long time, so a technology for effectively discharging heat generated from the motor is required.

Also, it is also required to reduce weights of the motor and components of the motor to increase the energy efficiency of the vehicle.

Typically, a cooling structure for heat dissipation of the motor may be implemented through an oil flow channel and a water flow channel. Since the two cooling materials have different properties, the two channels may be provided independently of each other. Also, a motor housing structure forming each of the channels may be required.

A motor housing implementing such cooling channel may be implemented with metal, in particular, aluminum material to satisfy requirements of heat resistance, shock resistance, wear resistance, and the like in general.

However, such metal housing may hinder the weight reduction of the motor structure and may increase a manufacturing cost.

SUMMARY

An aspect is to solve the issues of an increase in total weight, an increase in manufacturing cost, and the like due to a cooling structure in a motor structure.

According to an aspect, there is provided a motor housing assembly including an aluminum housing coupled to an outer circumferential surface of a motor assembly and configured to form a first space between the aluminum housing and the motor assembly, the first space including an oil flow channel and a plastic housing coupled to an outer circumferential surface of the aluminum housing and configured to form a second space between the plastic housing and the aluminum housing, the second space including a water flow channel.

The plastic housing may be coupled to the aluminum housing through press-fitting.

The motor housing assembly may further include an insertion chamfer at one axial end of the aluminum housing, the insertion chamfer including a surface inclined in a radially inward direction.

A first joining surface may be provided to be in contact with an inner circumferential surface of the plastic housing at one axial end of the outer circumferential surface of the aluminum housing.

The aluminum housing may further include a partition that protrudes from the outer circumferential surface in a radially outward direction, the partition being configured to form the water flow channel. The partition may include a second joining surface to be in contact with an inner circumferential surface of the plastic housing.

The partition may include a plurality of partitions, each of the partition being configured to extend to a predetermined length in an axial direction of the motor assembly. a first partition of a pair of adjacent partitions selected from the plurality of partitions extends axially from one axial end of the aluminum housing, and a second partition of the pair of adjacent partitions extends axially from an opposite axial end of the aluminum housing.

The plurality of partitions may include a shield wall that extends from the one end to the opposite end in the axial direction to block a flow of a cooling fluid. One of two channels adjacent to both sides of the shield wall may form an inlet channel and the other of the two channels may form an outlet channel.

An inner circumferential surface of the plastic housing may have a generally uniform diameter.

The motor housing assembly may further include a rear bracket coupled to the aluminum housing at one axial end of the aluminum housing and a rib configured to radially extend from an opposite axial end of the aluminum housing. One axial end of the plastic housing is in contact with the rear bracket and an opposite axial end of the plastic housing is in contact with the rib.

The rear bracket, the plastic housing, and the rib may be in contact with one another in an axial direction.

The motor housing assembly may further include a first O-ring provided between the plastic housing and the rear bracket, a second O-ring provided between the rear bracket and the aluminum housing, and a third O-ring provided between the aluminum housing and the plastic housing.

The motor housing assembly may further include a first recessed groove extending in an axial direction from a first surface of the rear bracket where the plastic housing and the rear bracket contact each other, the first recessed groove being configured to receive the first O-ring, a second recessed groove extending in a radial direction from a second surface of the rear bracket where the rear bracket and the aluminum housing contact each other, the second raises groove being configured to receive the second O-ring and a third recessed groove extending in the radial direction from a surface of the aluminum housing where the aluminum housing and the plastic housing contact each other, the third recessed groove being configured to receive the third O-ring.

The motor housing assembly may further include a water-cooling gate in the rear bracket, the water-cooling gate including a through-hole extending toward the second space.

The rear bracket may further include an insertion groove into which the aluminum housing is inserted.

The aluminum housing may be die-cast and the plastic housing may be injection-molded.

The aluminum housing may further include an oil-cooling gate formed in one side surface and connecting the first space with an external area to receive or discharge a cooling fluid.

The oil-cooling gate may include an oil-cooling inlet and an oil-cooling outlet. The oil-cooling inlet may be formed in an upper portion of one side surface of the aluminum housing. The oil-cooling outlet may be formed in a lower portion of the one side surface of the aluminum housing.

The aluminum housing may further include an extended channel configured to move the cooling fluid introduced through the oil-cooling inlet, toward one axial end of the motor assembly by a predetermined distance from an opposite axial end of the motor assembly.

The extended channel may include a drop hole through which a portion of the cooling fluid is configured to enter the first space after traveling by the predetermined distance toward the one axial end and a guide plate configured to direct a remaining portion of the cooling to enter the first space after traveling farther than the predetermined distance toward the one axial end.

The plastic housing may be cut by a first distance at the other end and the aluminum housing may be cut by the first distance at one end, so that the plastic housing and the aluminum housing are coupled.

