motor

Abstract

This invention provides an electric motor, comprising: a housing having an open end and a closed end; a water jacket fitted inside the housing, the water jacket having a first end and a second end opposite to the first end, the outer wall surface of the water jacket forming a recessed channel between the first end and the second end, the inner wall surface of the housing and the channel in the outer wall surface of the water jacket forming a water channel; a stator portion fitted inside the water jacket; a rotor portion inserted inside the stator portion; and an end cover configured to close the open end of the housing, wherein the water jacket and the housing form an interference fit, and the water jacket is welded to the housing by friction stir welding, thereby sealing the water channel formed by the channel in the inner wall surface of the housing and the outer wall surface of the water jacket. This invention simplifies the assembly process, improves dimensional and assembly accuracy, ensures reliable sealing of the water channel within the motor, and reduces motor manufacturing costs.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, and more specifically to a motor with a cooling water jacket. Background Technology

[0002] With the rapid development of electric motors, power density and lightweight design have received increasing attention. However, heat dissipation has become a major factor restricting further improvements in power density. Taking a common permanent magnet synchronous motor as an example, the stator windings generate a rotating magnetic field after an alternating current is applied. This rotating magnetic field couples with the permanent magnets on the rotor, driving the rotor to rotate. However, simultaneously, the rotating magnetic field induces eddy currents in the rotor and stator cores, causing them to heat up. The alternating current, in turn, causes the stator windings to heat up, with the stator windings generating the most heat and being the most difficult to dissipate. To increase the motor's power, a larger alternating current needs to be applied to the stator windings, but this also increases the heat generated by the stator core, stator windings, and rotor core. If this heat cannot be effectively dissipated, it may shorten the motor's lifespan or even cause it to overheat and burn out.

[0003] In existing technologies, a common solution for heat dissipation in motors is liquid cooling, where the stator is housed in a water jacket. A typical design uses pins and O-rings to mate the water jacket with the motor housing, ensuring torque transmission and sealing of the water channels. The motor assembly sequence is as follows: heat-fit the stator into the water jacket; after cooling, assemble the pins and O-rings into the water jacket; press the water jacket into the housing; install the housing seals; press the rotor into the housing; assemble the end caps with the housing; tighten the bolts; and assemble other accessories.

[0004] However, the current process of assembling the stator into the housing is cumbersome, requires high assembly precision, and necessitates equipment such as a press-fitting machine. The process of pressing the water jacket into the housing carries risks of water jacket tilting and cooling water leakage, and can also lead to O-ring cutting.

[0005] Therefore, how to simplify the assembly of the motor, improve the dimensional and assembly accuracy of the water jacket and the housing, and ensure the sealing of the water channel between the water jacket and the housing has become an urgent problem to be solved in the industry. Utility Model Content

[0006] The purpose of this invention is to solve the aforementioned problems existing in the prior art.

[0007] Therefore, according to one aspect of the present invention, an electric motor is provided, comprising: a housing having an open end and a closed end; a water jacket fitted inside the housing, the water jacket having a first end and a second end opposite to the first end, the outer wall surface of the water jacket forming a recessed channel between the first end and the second end, the inner wall surface of the housing and the channel in the outer wall surface of the water jacket forming a water channel; a stator portion fitted inside the water jacket; a rotor portion inserted into the stator portion; and an end cap configured to close the open end of the housing, wherein the water jacket forms an interference fit with the housing, and the water jacket is welded to the housing by friction stir welding, thereby sealing the water channel formed by the channel in the inner wall surface of the housing and the outer wall surface of the water jacket.

[0008] According to one embodiment of the present invention, a first interference fit position is formed between the outer wall surface of the water jacket at the first end and the inner wall surface of the housing, and a second interference fit position is formed between the outer wall surface of the water jacket at the second end and the inner wall surface of the housing. The water jacket forms the interference fit with the housing through the first interference fit position and the second interference fit position.

[0009] According to one embodiment of the present invention, the inner wall surface of the housing at the open end of the housing is provided with a recessed portion, the recessed portion having an axial surface and a radial surface, the radial surface of the recessed portion being flush with the end face of the first end of the water jacket, thereby forming a first stir friction welding position between the water jacket and the housing.

[0010] According to one embodiment of the present invention, the inner wall surface of the closed end of the housing is provided with a protrusion protruding axially into the housing, and the end of the second end of the water jacket is also provided with a radial extension extending radially into the water jacket. The radial extension of the second end abuts against the side of the protrusion along the inner wall surface of the closed end of the housing, and the inner wall surface of the water jacket of the radial extension is flush with the top surface of the protrusion of the closed end, thereby forming a second stir friction welding position between the water jacket and the housing.

[0011] According to one embodiment of the present invention, the water jacket is welded to the housing by friction stir welding performed at the first friction stir welding position and the second friction stir welding position.

[0012] According to one embodiment of the present invention, the housing is provided with a water inlet and a water outlet. The water inlet is connected to one end of the water channel, and the water outlet is connected to the other end of the water channel. Water flows into the water channel through the water inlet and flows out of the water channel through the water outlet.

[0013] According to one embodiment of the present invention, the channel formed on the outer wall of the water jacket between the first end and the second end is a spiral channel.

[0014] According to one embodiment of the present invention, the channel formed on the outer wall of the water jacket between the first end and the second end is a straight groove type channel.

[0015] According to one embodiment of the present invention, the housing is formed by die casting, and the water jacket is formed by aluminum drawing.

[0016] According to one embodiment of the present invention, the end cap has an annular flange, and when the end cap closes the open end of the housing, the annular flange of the end cap engages with the recess at the open end of the housing.

[0017] By using friction stir welding to weld the water jacket to the housing, the motor of this invention avoids the need to use O-rings to seal the spiral water channel formed by the spiral groove in the outer wall of the water jacket and the inner wall of the housing.

[0018] By using an interference fit between the water jacket and the housing, the motor of this invention avoids the need for pins to transmit the torque received by the stator in the opposite direction of rotation to the housing.

[0019] By welding the water jacket to the housing and then performing precision machining, the motor of this invention improves the dimensional accuracy and assembly accuracy of the housing with the water jacket.

[0020] The motor of this invention simplifies the assembly process, improves dimensional and assembly accuracy, ensures reliable sealing of the water channels inside the motor, and reduces the manufacturing cost of the motor. Attached Figure Description

[0021] The above and other features and advantages of this utility model will be better understood from the embodiments of this utility model described below with reference to the accompanying drawings. Wherein:

[0022] Figure 1 A cross-sectional view of a motor according to one embodiment of the present invention is shown; and

[0023] Figure 2 A three-dimensional cross-sectional view of the water jacket of an electric motor according to one embodiment of the present invention is shown. Detailed Implementation

[0024] The motor according to one embodiment of the present invention will now be described with reference to the accompanying drawings.

[0025] Please refer to Figure 1As shown, one embodiment of the motor of this utility model may include a housing 1, a water jacket 2, a stator portion 3, a rotor portion 4, and an end cover 5. The housing 1 is a generally cylindrical shell component used to house components such as the water jacket 2, stator portion 3, and rotor portion 4. The housing 1 includes an open end 11 and a closed end 12, through which the water jacket 2, stator portion 3, and rotor portion 4 can be assembled into the housing 1. The water jacket 2 is fitted into the housing 1 along the inner wall surface 13, and the water jacket 2 and housing 1 form an interference fit. The stator portion 3 typically includes a stator core formed by stacking cold-rolled sheets and windings formed by connecting several coils. The stator portion 3 is fixedly fitted into the water jacket 2. The rotor portion 4 is rotatably inserted at the center of the stator portion 3 for rotating within the electromagnetic field formed by the stator portion 3, thereby driving the output shaft of the motor to rotate. The end cover 5 is used to close the open end 11 of the housing 1. The end cover 5 is further used to fix the stator part 3 and the rotor part 4 of the motor, ensuring the stability of the motor's mechanical structure and preventing displacement or damage during operation. In addition, the end cover 5 is also used to seal the inside of the motor, preventing dust, moisture and other contaminants from entering the motor and protecting the internal components of the motor from the influence of the external environment.

[0026] Please refer to Figure 1 and Figure 2 As shown, the water jacket 2 is a generally cylindrical shell component, arranged coaxially with the housing 1. The water jacket 2 has a first end 21 and a second end 22 opposite to the first end 21. A recessed spiral channel 24 is formed on the cylindrical outer wall surface 23 of the water jacket 2 between the first end 21 and the second end 22. The spiral channel 24 is a channel that extends spirally along the axial direction of the water jacket 2 on the cylindrical outer wall surface 23 of the water jacket 2. The inner wall surface 13 of the motor housing 1 and the spiral channel 24 in the cylindrical outer wall surface 23 of the water jacket 2 form a water channel. An inlet and an outlet (not shown in the figure) are provided on the housing 1. The inlet is connected to one end of the spiral channel 24, and the outlet is connected to the other end of the spiral channel 24. Water can enter the spiral channel 24 through the inlet and finally flow out from the outlet. During the process of water flowing through the water channel, the motor can be cooled down. Although the water jacket 2 shown in the figure has a spiral channel 24, the cooling channel type of the water jacket 2 of this utility model is not limited to this. For example, according to actual design needs, the outer wall surface 23 of the water jacket 2 can be formed with a straight groove between the first end 21 and the second end 22.

[0027] According to one embodiment of the present invention, after the water jacket 2 is assembled onto the housing 1, a first interference fit position A is formed between the outer wall surface 23 of the water jacket 2 at the first end 21 and the inner wall surface 13 of the housing 1, and a second interference fit position B is formed between the outer wall surface 23 of the water jacket 2 at the second end 22 and the inner wall surface 13 of the housing 1.

[0028] During the process of the motor converting electrical energy into mechanical energy, when the current passes through the coils of the stator section 3 and generates a magnetic field, this magnetic field interacts with the magnetic field of the rotor section 4, producing a torque that drives the rotor section 4 to rotate. The stator section 3 experiences a torque in the opposite direction to the rotation of the rotor section 4. The water jacket 2, located between the stator section 3 and the housing 1, can transmit the torque in the opposite direction to the rotation of the rotor section 4 to the housing 1 at the first interference fit position A and the second interference fit position B.

[0029] The cylindrical inner wall surface 13 of the open end 11 of the housing 1 is provided with a recess 14, which has an axial surface 141 and a radial surface 142. The radial surface 142 of the recess 14 is flush with the end face 211 of the first end 21 of the water jacket 2, thereby forming the first friction stir welding position C between the water jacket 2 and the housing 1.

[0030] A protrusion 121 protruding axially into the interior of the housing 1 is provided on the inner wall surface of the closed end 12 of the housing 1. The end of the second end 22 of the water jacket 2 is also provided with a radial extension 221 extending radially into the interior of the housing 1. This radial extension 221 abuts against the side of the protrusion 121 of the closed end 12 along the inner wall surface of the housing 1. The inner wall surface of the radial extension 221 of the second end 22 of the water jacket 2 is flush with the top surface 1211 of the protrusion 121 of the closed end 12 of the housing 1, thereby forming the second friction stir welding position D between the water jacket 2 and the housing 1.

[0031] During the friction stir welding process between the water jacket 2 and the housing 1 at the first friction stir welding position C, the stirring head, while rotating at high speed, extends into the joint formed between the end face 211 of the first end 21 of the water jacket 2 and the radial surface 142 of the recess 14 of the housing 1. The heat generated by the friction between the stirring head and the end face 211 of the first end 21 of the water jacket 2 and the radial surface 142 of the recess 14 of the housing 1 causes localized melting of the welded material. As the rotating head moves forward along the joint formed by the flush end faces of the water jacket 2 and the housing 1, the plasticized material flows from the front to the rear of the rotating head under the rotational friction force, and forms a dense solid-phase weld under the pressure of the rotating head. Those skilled in the art will understand that, since both the water jacket 2 and the housing 1 are cylindrical shell components, the weld formed between the water jacket 2 and the housing 1 appears annular when viewed from the open end 11 of the housing 1.

[0032] Similarly, at the second friction stir welding position D, friction stir welding is performed on the inner wall surface of the radial extension 221 of the second end 22 of the water jacket 2 and the top surface 1211 of the protrusion 121 of the closed end 12 of the housing 1.

[0033] The advantages of using friction stir welding to weld the water jacket 2 and the housing 1 are that the microstructure changes in the heat-affected zone of the weld joint are small, the residual stress is low, and the welded workpiece is not easily deformed, thus ensuring the structural integrity of the water jacket 2 and the housing 1 after welding and avoiding deformation.

[0034] The following describes the assembly steps of a motor according to one embodiment of the present invention:

[0035] First, the housing 1 is heated to expand it, and then the water jacket 2 is pressed into the housing 1. After cooling, the water jacket 2 and the housing 1 form an interference fit. Specifically, the water jacket 2 forms a first interference fit position A between the outer wall surface 23 at the first end 21 and the inner wall surface 13 of the housing 1, and the water jacket 2 forms a second interference fit position B between the outer wall surface 23 at the second end 22 and the inner wall surface 13 of the housing 1.

[0036] Next, friction stir welding is performed at the first friction stir welding position C formed by the first end 21 of the water jacket 2 and the recess 14 of the open end 11 of the housing 1, and at the second friction stir welding position D formed by the radial extension 221 of the second end 22 of the water jacket 2 and the protrusion 121 of the closed end 12 of the housing 1, so as to seal the spiral water channel formed by the spiral channel 24 in the outer wall surface 23 of the water jacket 2 and the inner wall surface 13 of the housing 1.

[0037] Next, after completing the friction stir welding of the water jacket 2 and the housing 1, an aging treatment is performed to release the welding stress, thereby ensuring the welding strength and the dimensional stability of subsequent finishing.

[0038] Next, the housing with water jacket formed by welding water jacket 2 and housing 1 is precision machined to ensure the dimensional accuracy of water jacket 2 and housing 1 after assembly.

[0039] Next, the stator part 3 is pressed into the water jacket 2 from the first end 21 of the water jacket 2 along the inner wall surface of the water jacket 2, and then the rotor part 4 is inserted into the stator part 3.

[0040] Next, assemble the end cap 5 to the open end 11 of the housing 1 and tighten the bolts; and

[0041] Next, assemble the other accessories for the motor.

[0042] In some embodiments, the minimum cross-sectional dimension of the soft copper wire 6 inside the motor is 50 mm, so that when the end cover 5 is assembled to the open end 11 of the housing 1, it will not come into contact with the soft copper wire 6 and the winding 31 of the stator portion 3.

[0043] In some embodiments, the motor housing 1 is die-cast and the water jacket 2 is drawn aluminum.

[0044] In some embodiments, the end cover 5 of the motor has an annular flange 51. When the end cover 5 closes the open end 11 of the housing 1, the annular flange 51 of the end cover 5 engages with the recess 14 at the open end 11 of the housing 1.

[0045] By welding the water jacket 2 to the housing 1 using friction stir welding, the motor of this invention avoids the need to use O-rings to seal the spiral water channel formed by the spiral groove 24 in the outer wall surface 23 of the water jacket 2 and the inner wall surface 13 of the housing 1.

[0046] By forming an interference fit between the water jacket 2 and the housing 1, the motor of this invention avoids the use of pins to transmit the torque received by the stator part 3, which is opposite to the rotation direction of the rotor part 4, to the housing 1.

[0047] By welding the water jacket 2 to the housing 1 and then performing precision machining, the dimensional accuracy and assembly accuracy of the housing 1 with the water jacket 2 in this invention are improved.

[0048] The motor of this invention simplifies the assembly process, improves dimensional and assembly accuracy, ensures reliable sealing of the water channels inside the motor, and reduces the manufacturing cost of the motor.

[0049] While specific embodiments of the present invention have been described, they are presented by way of example only and are not intended to limit the scope of the invention. Rather, the structures described herein can be embodied in many other forms; furthermore, various substitutions and variations can be made to the structural forms described herein without departing from the spirit and scope of the invention.

Claims

1. An electric machine characterized in that, The motor includes: The housing has an open end and a closed end; A water jacket is fitted inside the housing. The water jacket has a first end and a second end opposite to the first end. A recessed groove is formed on the outer wall surface of the water jacket between the first end and the second end. The inner wall surface of the housing and the groove in the outer wall surface of the water jacket together form a water channel. The stator section is fitted inside the water jacket; The rotor portion, which is inserted into the stator portion; and An end cap, configured to close the open end of the housing. The water jacket is interference-fitted with the housing, and the water jacket is welded to the housing by friction stir welding, thereby sealing the water channel formed by the groove in the inner wall of the housing and the outer wall of the water jacket.

2. The electric machine of claim 1, wherein, The water jacket forms a first interference fit position between the outer wall surface of the water jacket at the first end and the inner wall surface of the housing, and forms a second interference fit position between the outer wall surface of the water jacket at the second end and the inner wall surface of the housing. The water jacket forms the interference fit with the housing through the first interference fit position and the second interference fit position.

3. The electric machine of claim 1, wherein, The inner wall surface of the housing at the open end of the housing is provided with a recess, the recess having an axial surface and a radial surface. The radial surface of the recess is flush with the end face of the first end of the water jacket, thereby forming the first stir friction welding position between the water jacket and the housing.

4. The electric machine of claim 3, wherein, The inner wall surface of the closed end of the housing is provided with a protrusion protruding axially into the housing. The end of the second end of the water jacket is also provided with a radial extension extending radially into the water jacket. The radial extension of the second end abuts against the side of the protrusion along the inner wall surface of the closed end of the housing. The inner wall surface of the water jacket of the radial extension is flush with the top surface of the protrusion of the closed end, thereby forming the second friction stir welding position between the water jacket and the housing.

5. The electric machine of claim 4, wherein, The water jacket is welded to the housing by friction stir welding performed at the first and second friction stir welding positions.

6. The electric machine of claim 1, wherein, The casing is provided with a water inlet and a water outlet. The water inlet is connected to one end of the water channel, and the water outlet is connected to the other end of the water channel. Water flows into the water channel through the water inlet and flows out of the water channel through the water outlet.

7. The electric machine of claim 1, wherein, The channel formed on the outer wall of the water jacket between the first end and the second end is a spiral channel.

8. The electric machine of claim 1, wherein, The channel formed on the outer wall of the water jacket between the first end and the second end is a straight groove type.

9. The electric machine of claim 1, wherein, The housing is formed by die casting, and the water jacket is formed by aluminum drawing.

10. The electric machine of claim 3, wherein, The end cover of the motor has an annular flange. When the end cover closes the open end of the housing, the annular flange of the end cover engages with the recess at the open end of the housing.

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