Patent Publication Number: US-2021184542-A1

Title: Motor housing with an integrated cooling passage

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Korean Patent Application No. 10-2019-0165710, filed Dec. 12, 2019, the entire contents of which are incorporated herein for all purposes by this reference. 
     BACKGROUND OF THE DISCLOSURE 
     Field of the Disclosure 
     The present disclosure relates to a cooling-passage integrated motor housing, i.e. a motor housing with an integrated cooling passage, in which a motor housing and a cooling pipe are integrally formed. 
     Description of the Related Art 
     An eco-friendly vehicle is equipped with an electric motor that drives the vehicle by the power of a high-voltage battery. A driving motor is composed of main components to generate output, such as a permanent magnet, a core, or a coil. Due to electric resistance or magnetic resistance generated in the components when a current or a magnetic force flows, heat is generated in the motor. This may result in irreversible deterioration of component performance under high-temperature conditions above a certain temperature. Such deterioration leads to damage to the components and degradation of motor performance. Therefore, in order to maintain the motor performance, cooling is essential to keep the motor temperature at a predetermined level. If the motor temperature may be kept low by cooling, a motor driving time can be increased and, consequently, the fuel efficiency and operability of the eco-friendly vehicle can be improved. 
     An air cooling method of cooling a motor may be used in which a heat dissipation fin is formed in a motor housing to perform a cooling operation by external cooling air. A water cooling method of cooling a motor may be used in which a cooling channel is formed inside the motor housing or outside a stator to perform a cooling operation by coolant. The motor to which the water cooling method is applied includes a support ring that connects a stator core and a housing and defines a path in which coolant circulates. The support ring is disposed between the stator core and the housing to connect the stator core and the housing. A cooling passage is formed between the support ring and the housing. However, this is problematic in that a process is complicated due to a support-ring coupling process and in that the support ring is additionally required. Thus, the cost for manufacturing the motor is increased. Furthermore, the cooling passage between the support ring and the housing is not manufactured in a sealed structure. As a result, coolant may leak out and thus the performance of the motor may be degraded. 
     SUMMARY OF THE DISCLOSURE 
     The present disclosure has been made in order to solve the above-mentioned problems in the related art. An objective of the present disclosure is to provide a motor housing with an integrated cooling-passage that cools a stator core through a cooling pipe inserted into a motor housing. 
     Another objective of the present disclosure is to provide a motor housing with an integrated cooling-passage that has a cooling pipe integrally provided in a motor housing so as to prevent the leakage of coolant. 
     In order to achieve the objectives of the present disclosure, the disclosure provides a cooling-channel integrated motor housing, i.e., a motor housing with an integrated cooling-channel. The cooling-channel integrated motor housing includes a motor housing, a plurality of stator cores press-fit into the motor housing, and a cooling pipe inserted into the motor housing and disposed in a circumferential direction of a circle along which the stator cores are arranged. The cooling pipe is disposed to overlap with the stator cores in a direction perpendicular to a direction in which a rotating shaft of a motor extends. 
     The cooling pipe may be connected to a coolant injection nipple and a coolant discharge nipple installed in the motor housing. The motor housing may include a first region between the coolant injection nipple and the coolant discharge nipple and may include a second region other than the first region. 
     The cooling pipe may be provided in two stages in a direction parallel to the rotating shaft of the motor. The coolant discharge nipple may be disposed on an upper stage of the motor housing in the direction in which the rotating shaft extends. The coolant injection nipple may be disposed on a lower stage of the motor housing. 
     The cooling pipe may be provided in one stage in the first region and the cooling pipe may be provided in two stages in the second region. 
     The cooling pipe in the second region may be disposed so as not to protrude above a height level of an upper surface of the stator core and below a height level of a lower surface thereof in a direction parallel to the rotating shaft of the motor. 
     The cooling pipe may include a bent part that is bent from the lower stage to the upper stage of the motor housing by a sensor connector provided in the first region. 
     A water pump and a clutch actuator may be attached to the motor housing. The water pump and the clutch actuator may be attached to the second region of the motor housing. 
     One end and the other end of the cooling pipe connected to the coolant injection nipple and the coolant discharge nipple may be bent in a circumferential direction with respect to the rotating shaft of the motor. 
     A high-voltage connector and a sensor connector may be provided in the first region. 
     The cooling pipe may be formed of an aluminum material. 
     According to an embodiment of the present disclosure, a stator core is fixed to a motor housing through a press-fitting process, thus eliminating a separate component (existing support ring) for connecting the motor housing to the stator core. As the support ring is eliminated, a process of manufacturing a driving motor can be simplified and the cost of manufacturing the driving motor can be saved. 
     According to an embodiment of the present disclosure, the position of a cooling pipe may be disposed at a height similar to that of a stator core. In other words, the coolant circulating in the cooling pipe may approach the stator core as close as possible to cool the stator core. Therefore, the efficiency of cooling the stator core can be improved. 
     According to an embodiment of the present disclosure, since a cooling pipe is inserted into a motor housing, a space in which the motor housing and a peripheral component may be connected may be insufficient. Therefore, the peripheral component of a driving motor may be connected to a space between a coolant injection nipple and a coolant discharge nipple and in which the cooling pipe is wound relatively less. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing a driving motor according to an embodiment of the present disclosure; 
         FIG. 2  is a perspective view showing a cooling-channel integrated motor housing according to the embodiment of the present disclosure; 
         FIG. 3  is a plan view showing the cooling-channel integrated motor housing according to the embodiment of the present disclosure; 
         FIG. 4  is a diagram showing the driving motor and peripheral components attached to the driving motor according to the embodiment of the present disclosure; 
         FIG. 5  is a diagram showing a bent part of a cooling pipe according to the embodiment of the present disclosure; and 
         FIG. 6  is a diagram showing a cooling pipe according to a modification of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE 
     The above and other objects, features, and other advantages of the present disclosure will be more clearly understood from the following detailed description when taken in conjunction with the accompanying drawings. However, the disclosure should not be limited to embodiments set forth herein and may be implemented in a variety of forms. The embodiments described herein are provided to make the disclosure complete and to fully convey the spirit of the disclosure to those having ordinary skill in the art. The disclosure is defined merely by the scope of claims. The same reference numerals are used throughout the drawings to designate the same components. 
     The terms “ . . . part”, “ . . . unit”, “ . . . module” and the like described herein may mean a unit for processing at least one function or operation, and they may be implemented in hardware, software or a combination of hardware and software. 
     Furthermore, the terms “first”, “second” and the like are used herein to divide components in the same relationship but are not necessarily limited to a particular order in the following description. 
     The detailed description is for illustrative purpose only. In addition, the foregoing is intended to illustrate embodiments of the present disclosure. The present disclosure may be used in a variety of different combinations, modifications, and embodiments. In other words, changes or modifications may be made within the scope of the concept of the disclosure disclosed herein, equivalents of the disclosure, and/or the ordinary skill or knowledge in the art. The embodiments describe the best mode for implementing the technical spirit of the present disclosure, and various modifications are possible in the specific application field and use of the present disclosure. Therefore, the above description of the embodiments is not intended to limit the disclosure to the disclosed embodiments. Furthermore, the appended claims should be construed as including other embodiments. 
       FIG. 1  is a diagram showing a driving motor according to an embodiment of the present disclosure. 
     Referring to  FIG. 1 , the driving motor  1  may include a motor housing  100 , a cooling pipe  200 , a stator core  300 , a bobbin  400 , and a rotor core  500 . The driving motor  1  according to the embodiment of the present disclosure may be applied to a hybrid electric vehicle (HEV) or an electric vehicle (EV). The driving motor  1  may include the stator core  300  that is fixedly installed in the motor housing  100  to generate a magnetic flux. The driving motor  1  may also include the rotor core  500  that is disposed to be spaced apart from the stator core  300  by a predetermined gap and that rotates about a rotating shaft  50  as a driving shaft. 
     The motor housing  100  may be disposed to surround a plurality of stator cores  300 . The stator cores  300  may be fixed to the motor housing  100  by press-fitting. The stator cores  300  may be fixed to be in direct contact with an inner surface of the motor housing  100 . The bobbin  400  may be installed in each of the stator cores  300 . A coil  450  may be wound around each bobbin  400 . 
     The rotor core  500  may be disposed to be spaced apart from the stator core  300  by the predetermined gap. The rotor core  500  may be rotated by the rotation of the rotating shaft  50 . The magnetic flux may be generated in the coil wound around the stator core  300  by the rotation of the rotor core  500 . 
     The cooling pipe  200  may be inserted into the motor housing  100 . The cooling pipe  200  may be disposed in the circumferential direction of a circle where the stator cores  300  are arranged. In other words, the cooling pipe  200  may be disposed to surround the stator cores  300  that are arranged about the rotating shaft  50  in the circumferential direction. The cooling pipe  200  may be disposed to overlap with the stator cores  300  in a direction perpendicular to a direction in which the rotating shaft  50  extends, thus serving as a path in which coolant for cooling the stator cores  300  flows. For example, the cooling pipe  200  may be formed of an aluminum material. The cooling pipe  200  may have a circular section. However, the sectional shape of the cooling pipe  200  may not be particularly limited. 
     The cooling pipe  200  may be provided in two stages in a direction parallel to the rotating shaft  50 . When referring to the sectional shape of  FIG. 1 , two cooling pipes  200  may be disposed to overlap with each other in a vertical direction. The cooling pipe  200  may be disposed to surround the stator cores  300  in the motor housing  100  multiple times. The cooling pipe  200  may be disposed within a range defined by one surface and the other surface of the bobbin  400  in a direction parallel to the rotating shaft  50 . The one surface of the bobbin  400  may be a surface having the highest level in a direction parallel to the rotating shaft  50 . The other surface of the bobbin  400  may be a surface having the lowest level in a direction parallel to the rotating shaft  50 . 
     According to the embodiment of the present disclosure, the stator core  300  is fixed to the motor housing  100  through a press-fitting process. Thus, a separate component (existing support ring) for connecting the motor housing  100  to the stator core  300  may be eliminated. As the support ring is eliminated, a process of manufacturing the driving motor  1  may be simplified, and the cost of manufacturing the driving motor  1  may be reduced. 
     According to the embodiment of the present disclosure, the cooling pipe  200  may be inserted into the motor housing  100  as close as possible to the stator core  300 . Furthermore, a designer can design the diameter of the cooling pipe  200  as large as possible in the motor housing  100 , thus improving the performance of cooling the stator core  300 . 
       FIG. 2  is a perspective view showing a cooling-channel integrated motor housing, i.e., a motor housing with an integrated cooling channel, according to the embodiment of the present disclosure. 
     Referring to  FIGS. 1 and 2 , the cooling pipe  200  may be disposed in the motor housing  100  to be wound multiple times. As the cooling pipe  200  is disposed to be wound multiple times, a portion of the cooling pipe  200  may be disposed relatively on an upper portion, and another portion of the cooling pipe  200  may be disposed relatively on a lower portion. In order to clearly describe the arrangement of the cooling pipe  200 , the motor housing  100  is described in a two-layer structure. 
     The motor housing  100  may be formed in the two-layer structure in a direction in which the rotating shaft  50  extends. A coolant discharge nipple  230  may be disposed on an upper stage  100   a  of the motor housing  100 . A coolant injection nipple  210  may be disposed on a lower stage  100   b  of the motor housing  100 . The coolant injection nipple  210  and the coolant discharge nipple  230  are configured to be connected to the cooling pipe  200 . The coolant injection nipple  210  and the coolant discharge nipple  230  may be connected to one end and the other end of the cooling pipe  200 . The coolant injection nipple  210  and the coolant discharge nipple  230  may protrude in the circumferential direction of the motor housing  100  with respect to the rotating shaft  50 . Therefore, one end and the other end of the cooling pipe  200  connected to the coolant injection nipple  210  and the coolant discharge nipple  230  may be bent in the circumferential direction with respect to the rotating shaft  50  within the motor housing  100 . 
     According to the embodiment of the present disclosure, as the coolant is introduced and discharged by the coolant injection nipple  210  and the coolant discharge nipple  230 , there is no risk that the coolant will leak into the driving motor  1 . Thus, the performance of the driving motor is prevented from being deteriorated due to the leakage of the coolant. 
       FIG. 3  is a plan view showing the cooling-channel integrated motor housing according to the embodiment of the present disclosure. 
     Referring to  FIGS. 1 and 3 , the motor housing  100  may be divided into a first region  110  and a second region  130  according to the wound state of the cooling pipe  200 . The first region  110  may mean a space between the coolant injection nipple  210  and the coolant discharge nipple  230 , and the second region  130  may be a space other than the first region  110 . For example, the first region  110  may mean a space that is relatively smaller than the second region  130 . 
     The cooling pipe  200  may be provided in one stage in the first region  110 , and the cooling pipe  200  may be provided in two stages in the second region  130 . In other words, the second region  130  of the motor housing  100  may mean a portion where the cooling pipe  200  is wound several times, and the first region  110  of the motor housing  100  may mean a portion where the cooling pipe  200  is wound once. The cooling pipe  200  may be provided in two stages to overlap in a direction parallel to the rotating shaft  500 . The cooling pipe  200  may be connected to the coolant injection nipple  210  into which the coolant flows and to the coolant discharge nipple  230  out of which the coolant flows. Also, the coolant injection nipple  210  and the coolant discharge nipple  230  may protrude out from the motor housing  100 . As a result, there may be a portion where the cooling pipe  200  is relatively less wound about the rotating shaft  50 . In the embodiment of the present disclosure, the portion where the cooling pipe  200  is wound a relatively small number of times is defined as the first region  110 . 
     A high-voltage connector  600  and a sensor connector  700  may be attached to the first region  110  of the motor housing  100 . The high-voltage connector  600  may be a component for supplying power to the driving motor  1 . The sensor connector  700  may be a component that is connected to a component (e.g. a resolver) for reading the position of the rotor  500  of the driving motor  1  and that is used to input and output a signal. The high-voltage connector  600  and the sensor connector  700  should be essentially connected to the driving motor  1 . As a result, they may be connected to the motor housing  100  between the coolant injection nipple  210  and the coolant discharge nipple  230 . Portions at which the high-voltage connector  600  and the sensor connector  700  are connected to the motor housing  100  may be limited by the cooling pipe  200  that is inserted into the motor housing  100  to surround the stator core  300 . Therefore, the high-voltage connector  600  and the sensor connector  700  may be connected to the first region  110 . The first region  110  can have a relatively large space in the motor housing  100  because the cooling pipe  200  is wound a relatively small number of times. 
     In the embodiment of the present disclosure, since the cooling pipe  200  is inserted into the motor housing  100 , a space in which the motor housing  100  and a peripheral component may be connected may be insufficient. Therefore, the peripheral component of the driving motor  1  may be connected to a space between the coolant injection nipple  210  and the coolant discharge nipple  230  and in which the cooling pipe  200  is wound relatively less. Thus, even if an area of the cooling pipe  200  occupied in the motor housing  100  is increased, the peripheral component of the driving motor  1  and the motor housing  100  may be easily connected to each other. 
       FIG. 4  is a diagram showing the driving motor and peripheral components attached to the driving motor according to the embodiment of the present disclosure. 
     Referring to  FIGS. 3 and 4 , the peripheral components may be attached to the driving motor  1 . The peripheral components may be divided into a component that applies power or a control signal to the driving motor  1  and into a component that is attached to the motor housing  100  on a fastening structure of an engine and a transmission. 
     The high-voltage connector  600  and the sensor connector  700  may be attached to the first region  110  of the motor housing  100 . The high-voltage connector  600  may be the component for supplying power to the driving motor  1 . The sensor connector  700  may be the component that is connected to the component (e.g. a resolver) for reading the position of the rotor  500  and is used to input and output the signal. Since the high-voltage connector  600  and the sensor connector  700  are components that are directly associated with the driving of the driving motor  1 , they may be physically/electrically connected to components disposed in the driving motor  1 . Therefore, an interior of a portion of the motor housing  100  requires a space in which components for physical/electrical connection are disposed and to which the high-voltage connector  600  and the sensor connector  700  are connected. 
     A water pump  800  and a clutch actuator  900  may be disposed in the second region  130  of the motor housing  100 . The water pump  800  and the clutch actuator  900  may not be components that are directly associated with the driving of the driving motor  1 . In other words, the water pump  800  and the clutch actuator  900  may be components that are driven independently of the driving motor  1 . Therefore, even if the water pump  800  and the clutch actuator  900  are attached to the second region  130 , which has a relatively small space in the motor housing  100 , they may not affect the driving of the driving motor  1 . 
       FIG. 5  is a diagram showing a bent part of the cooling pipe according to the embodiment of the present disclosure. 
     Referring to  FIGS. 2, 3, and 5 , the cooling pipe  200  may have the bent part  250  that is bent from a lower stage  100   b  to an upper stage  100   a  of the motor housing  100  by the sensor connector  700  provided in the first region  110  of the motor housing  100 . The bent part  250  may mean a portion of the cooling pipe  200 . The sensor connector  700  is attached to the first region  110 , and the sensor connector  700  and the cooling pipe  200  should be spaced apart from each other. However, because the cooling pipe  200  is disposed on the lower stage  100   b  of the motor housing  100  in the first region  110 , and because the sensor connector  700  is also spaced apart from the high-voltage connector  600 , the bent part may be disposed on the lower stage  100   b  of the motor housing  100 . Therefore, a portion of the cooling pipe  200  may be bent to be spaced apart from the sensor connector  700 . According to the embodiment of the present disclosure, the bent part  250  of the cooling pipe  200  may be disposed on a portion adjacent to the high-voltage connector  600  and the sensor connector  700 . The cooling pipe  200  may be bent towards the upper stage  100   a  of the motor housing  100  to avoid the sensor connector  700  disposed on the lower stage  100   b  of the motor housing  100 . This part of the cooling pipe  200  may be defined as the bent part  250 . 
       FIG. 6  is a diagram showing a cooling pipe according to a modification of the present disclosure. 
     Referring to  FIGS. 1 and 6 , the arrangement relationship between the cooling pipe  200  and the stator core  300  may be changed to increase the efficiency of cooling the stator core  300 . To be more specific, the cooling pipe  200  may be disposed to overlap with the stator cores  300  in a direction perpendicular to a direction in which the rotating shaft  50  of the driving motor  1  extends. The cooling pipe  200  may be located at the same height level as the stator cores  300  in the direction in which the rotating shaft  50  extends. A portion of the cooling pipe  200  may be disposed on the upper stage  100   a  of the motor housing  100 , and another portion of the cooling pipe  200  may be disposed on the lower stage  100   b  of the motor housing  100 . 
     By way of example, the cooling pipe  200  in the second region of the motor housing  100  may be arranged so as not to protrude above a height level H 1  of an upper surface of the stator core  300  and below a height level H 2  of a lower surface thereof in a direction parallel to the rotating shaft  500  of the driving motor  1 . 
     Unlike the above-described example, the cooling pipe  200  in the second region of the motor housing  100  may be arranged so as not to protrude above a height level of an upper surface of the bobbin  400  and below a height level of a lower surface thereof in the direction parallel to the rotating shaft  500  of the driving motor  1 . 
     According to the embodiment of the present disclosure, the position of the cooling pipe  200  may be disposed at a height similar to that of the stator core  300 . In other words, the coolant circulating in the cooling pipe  200  may approach the stator core  300  as close as possible to cool the stator core  300 . Therefore, the efficiency of cooling the stator core  300  can be improved. 
     Although the present disclosure has been described with reference to specific embodiments shown in the drawings, it should be apparent to those having ordinary skill in the art that the present disclosure may be changed and modified in various ways without departing from the scope of the present disclosure, which is described in the following claims. Therefore, it should be understood that the above-described embodiments are illustrative in all aspects but are not restrictive.