WO2017018578A1 - Electric motor and manufacturing method thereof - Google Patents

Electric motor and manufacturing method thereof Download PDF

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Publication number
WO2017018578A1
WO2017018578A1 PCT/KR2015/008697 KR2015008697W WO2017018578A1 WO 2017018578 A1 WO2017018578 A1 WO 2017018578A1 KR 2015008697 W KR2015008697 W KR 2015008697W WO 2017018578 A1 WO2017018578 A1 WO 2017018578A1
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WO
WIPO (PCT)
Prior art keywords
case
cooling
oil
rib
path
Prior art date
Application number
PCT/KR2015/008697
Other languages
French (fr)
Inventor
Namhoon JUNG
Original Assignee
Lg Electronics Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to KR1020150105268A priority Critical patent/KR101700769B1/en
Priority to KR10-2015-0105268 priority
Application filed by Lg Electronics Inc. filed Critical Lg Electronics Inc.
Publication of WO2017018578A1 publication Critical patent/WO2017018578A1/en

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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K5/00Casings; Enclosures; Supports
    • H02K5/04Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/20Casings or enclosures characterised by the shape, form or construction thereof with channels or ducts for flow of cooling medium
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K9/00Arrangements for cooling or ventilating
    • H02K9/02Arrangements for cooling or ventilating by ambient air flowing through the machine
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K9/00Arrangements for cooling or ventilating
    • H02K9/19Arrangements for cooling or ventilating for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil
    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02KDYNAMO-ELECTRIC MACHINES
    • H02K9/00Arrangements for cooling or ventilating
    • H02K9/19Arrangements for cooling or ventilating for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil
    • H02K9/20Arrangements for cooling or ventilating for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil wherein the cooling medium vaporises within the machine casing

Abstract

Disclosed are an electric motor and a manufacturing method thereof. The electric motor comprises a case forming a receiving space therein; a stator received in the case; a rotor performing relative motion with respect to the stator; and a cooling path portion forming a path of a cooling fluid on an outer surface of the case, wherein the cooling path portion includes an outer rib projected toward the outer surface of the case and extended along a circumferential direction to form a receiving space of the cooling fluid therein; inner ribs projected from the outer surface of the case at an inner side of the outer rib, extended axially, and spaced apart from one another along a circumferential direction to form the path of the cooling fluid; and a cooling path cover arranged along a radius direction of the case to block the outsides of the outer rib and the inner rib to form the path of the cooling fluid together with the outer rib and the inner rib. In this case, a heat exchange area of the cooling fluid may be increased to raise cooling performance.

Description

ELECTRIC MOTOR AND MANUFACTURING METHOD THEREOF
The present disclosure relates to an electric motor and a manufacturing method thereof, and more particularly to, an electric motor and a manufacturing method thereof, which may raise power density by boosting cooling.
As is generally known, an electric motor is a device that converts electric energy to dynamic energy by using strength of a current-carrying conductor, which is received in a magnetic field.
The electric motor is categorized into a direct current electric motor and an alternating current electric motor depending on types of power sources.
The electric motor generally includes a stator, and a rotor arranged to enable relative motion with respect to the stator.
The rotor is configured to enable rotation or linear reciprocating motion with respect to the stator.
The electric motor includes a case that may receive the stator and the rotor therein.
A temperature of the electric motor rises due to heating action of the stator and the rotor when the electric motor is driven.
If the temperature of the electric motor rises excessively, output (power density) of the electric motor is deteriorated.
Considering the above aspect, the electric motor is provided with a cooling means.
Examples of the cooling means include an air cooling means based on the air and a water cooling means based on a cooling fluid (cooling water).
Also, a method for boosting cooling by sealing the inside of the case of the electric motor and injecting cooling oil into the case is used for some electric motors.
The water cooling means of which cooling capacity is relatively great is used for an electric motor having relatively high power density and/or heating capacity.
However, in the conventional electric motors described as above, as a helical path of a cooling fluid is formed around the case, a heat exchange area between the cooling fluid and the case is relatively small, whereby there is limitation in raising cooling performance.
As a result, a problem occurs in that the temperature of the stator and/or the rotor rises excessively, whereby output (power density) is deteriorated relatively.
Also, a cooling path is formed in such a manner that a helical pipe is inserted into the case to flow cooling water, whereby a wall thickness of the case becomes thick. As a result, a problem occurs in that appearance size and weight of the case are increased significantly.
Also, it is difficult to manufacture the electric motor in such a manner that a helical pipe is inserted into the case, whereby a problem occurs in that the manufacturing cost is increased.
[Prior Art Reference]
[Patent Reference]
(Patent Reference 1) KR101062191 B1 (laid-open on September 5, 2011)
(Patent Reference 2) KR1020121851 A (published on September 5, 2011)
Therefore, an object of the present invention is to provide an electric motor and a manufacturing method thereof, which may raise cooling performance by increasing a heat exchange area of a cooling fluid.
Another object of the present invention is to provide an electric motor and a manufacturing method thereof, which may facilitate manufacture and reduce the manufacturing cost.
Still another object of the present invention is to provide an electric motor and a manufacturing method thereof, which may boost cooling of components inside a case.
Further still another object of the present invention is to provide an electric motor and a manufacturing method thereof, which may simultaneously cool the inside and the outside of a case by using different fluids.
Further still another object of the present invention is to provide an electric motor and a manufacturing method thereof, which may quickly cool cooling oil inside a case.
Further still another object of the present invention is to provide an electric motor and a manufacturing method thereof, which may boost circulation of cooling oil inside a case.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described herein, there is provided an electric motor comprising a case forming a receiving space therein; a stator received in the case; a rotor performing relative motion with respect to the stator; and a cooling path portion forming a path of a cooling fluid on an outer surface of the case, wherein the cooling path portion includes an outer rib projected toward the outer surface of the case and extended along a circumferential direction to form a receiving space of the cooling fluid therein; inner ribs projected from the outer surface of the case at an inner side of the outer rib, extended axially, and spaced apart from one another along a circumferential direction to form the path of the cooling fluid; and a cooling path cover arranged along a radius direction of the case to block the outsides of the outer rib and the inner rib to form the path of the cooling fluid together with the outer rib and the inner rib.
In the embodiment, the outer rib may include circumferential section portions formed on the outer surface of the case along a circumferential direction and spaced apart from one another along an axial direction, and connecting section portions connecting both ends of the circumferential section portions with each other.
In this case, each of the inner rib may have a length reduced as compared with a distance between the circumferential section portions, and its one end may be connected to any one of the circumferential section portions and its other end may be spaced apart from the other one of the circumferential section portions to form a communication portion to which the cooling fluid is moved.
The outer rib may be provided with an inlet portion through which the cooling fluid flows into the outer rib, and an outlet portion through which the cooling fluid inside the outer rib flows out.
In the embodiment, cooling oil may be injected(introduced) into the case.
In the embodiment, the electric motor may further comprise an oil cooling portion for cooling the oil.
In this case, the oil cooling portion may include a pass-through portion formed to pass through the case, and an oil cooling grill coupled to the pass-through portion, having one side which is in contact with the oil inside the case and the other side which is in contact with the air outside the case.
The oil cooling grill may include a grill body coupled to the pass-through portion, and cooling plates which are projected from the grill body, in contact with the oil inside the case through the pass-through portion, and spaced apart from one another at a predetermined distance.
Each cooling plate may be provided with an air path cut in a thickness direction to move the air therethrough.
In the embodiment, an oil receiving portion for temporarily receiving the oil may be formed at a lower side of the case, the pass-through portion may be formed in the oil receiving portion, and the cooling plates may be inserted into the oil receiving portion through the pass-through portion.
The outer rib may be arranged above the pass-through portion.
In the embodiment, the oil cooling portion may includes an oil cooling path through which the oil inside the case is cooled while circulating by passing through the outside of the case, and an oil pump provided in the oil cooling path to circulate the oil.
The oil cooling path may be provided with an oil heat exchanger for heat-exchanging the oil ejected from the case with the air or water.
In the embodiment, the electric motor may further comprise an oil feeding portion provided in the rotor to feed the oil accommodated in a lower side of the case to an upper area when the rotor is rotated.
The oil feeding portion may include a plate portion having a disk shape and a plurality of blades projected from the plate portion and spaced apart from one another along a circumferential direction.
In the embodiment, the stator may include a stator core, and a stator coil wound in the stator core, and the electric motor may further comprise an oil guide provided in the case to guide the oil, which is upwardly fed by the oil feeding portion when the rotor is rotated, between a coil end of the stator coil and the case.
The case may include a cylindrical portion and a bracket blocking both ends of the cylindrical portion, and the oil guide may be projected from an inner surface of the bracket and may have a projected end arranged between the coil end and the cylindrical portion.
In the embodiment, the electric motor may further comprise a heat pipe having one end which is in contact with the stator and the other end which is exposed to the outside of the case to radiate heat of the stator to the outside of the case.
In this case, the electric motor may further comprise a radiating fin coupled to the exposed end of the heat pipe to boost heat exchange.
In the embodiment, the heat pipe may be configured as a plurality of heat pipes spaced apart from one another along a circumferential direction of the case, and the radiating fin may have an arc shape to be coupled to the heat pipes.
In the embodiment, the heat pipe may include a heat conducting portion having one end connected to the heat pipe and the other end which is in contact with the coil end of the stator coil to enable heat transfer.
In the embodiment, the electric motor may further comprise a heat conducting member inserted into between the coil end of the stator coil and the heat pipe to enable heat transfer.
In another aspect of the present invention, according to another embodiment, there is provided a method of manufacturing an electric motor, which comprises the steps of preparing a case that forms a receiving space therein; forming a cooling path portion that forms a path of a cooling fluid on an outer surface of the case; arranging a stator inside the case; and arranging a rotor, which performs relative motion with respect to the stator, inside the case, wherein the cooling path portion includes an outer rib projected toward the outer surface of the case and extended along a circumferential direction to form a receiving space of the cooling fluid therein, inner ribs projected from the outer surface of the case at an inner side of the outer rib, extended axially, and spaced apart from one another along a circumferential direction to form the path of the cooling fluid, and a cooling path cover arranged along a radius direction of the case to block the outsides of the outer rib and the inner rib to form the path of the cooling fluid together with the outer rib and the inner rib, and the step of forming the cooling path portion includes forming the inner ribs on the outer surface of the case; forming the outer rib on an inner surface of the cooling path cover; and coupling the cooling path cover to the outer surface of the case to form the path of the cooling fluid.
In other aspect of the present invention, there is provided a method of manufacturing an electric motor, which comprises the steps of preparing a case that forms a receiving space therein; forming a cooling path portion that forms a path of a cooling fluid on an outer surface of the case; arranging a stator inside the case; and arranging a rotor, which performs relative motion with respect to the stator, inside the case, wherein the cooling path portion includes an outer rib projected toward the outer surface of the case and extended along a circumferential direction to form a receiving space of the cooling fluid therein, inner ribs projected from the outer surface of the case at an inner side of the outer rib, extended axially, and spaced apart from one another along a circumferential direction to form the path of the cooling fluid, and a cooling path cover arranged along a radius direction of the case to block the outsides of the outer rib and the inner rib to form the path of the cooling fluid together with the outer rib and the inner rib, and the step of forming the cooling path portion includes forming the cooling path cover; forming the outer rib and the inner ribs on the outer surface of the case or an inner surface of the cooling path cover; and coupling the cooling path cover to the outer surface of the case to form the path of the cooling fluid.
In the embodiment, the step of forming the outer rib may include forming an inlet portion through which the cooling fluid flows into the outer rib; and forming an outlet portion through which the cooling fluid inside the outer rib flows out.
In the embodiment, the method may further comprise the step of arranging a sealing member, which prevents the cooling fluid from leaking out, at a contact area between the cooling path cover and the case before the step of coupling the cooling path cover to the outer surface of the case.
As described above, according to one embodiment of the present invention, the electric motor is provided with the outer rib projected toward the outer surface of the case, the inner ribs, and the cooling path cover for blocking the outer rib and the inner ribs, whereby a heat exchange area of the cooling fluid may be increased to raise cooling performance.
Also, as the outer rib and the inner ribs are simultaneously formed on the outer surface of the case when the case is manufactured, manufacture may be facilitated and the manufacturing cost may be reduced.
Also, the outer surface of the case forms a part (one sidewall) of the cooling path and the communication portion is formed between the outer rib and the inner rib, whereby flow resistance of the cooling fluid may be reduced to reduce a dynamic power required for pumping of the cooling fluid.
Also, as the outside and the inside of the case are cooled using different cooling fluids, the inside and the outside of the case may be cooled quickly at the same time.
Also, as the cooling oil is injected into the case, a component inside the case, which is in contact with the air to be difficult for cooling, is in contact with the cooling oil, whereby cooling may be made quickly.
Also, as the oil cooling portion for cooling the cooling oil inside the case is provided, the cooling oil may be cooled quickly.
Also, as the oil circulating portion for boosting circulation of the cooling oil inside the case is provided, circulation of the oil is boosted, whereby cooling of the component inside the case may be more boosted by the oil.
Also, as the oil guide for guiding the oil between the coil end of the stator coil and the cylindrical portion of the case is provided, cooling of the coil end of the stator coil may be boosted.
Also, as the heat pipe having one end which is in contact with the stator coil and the other end which is exposed to the outside of the case is provided, radiating of the stator coil, especially radiating of the coil end of the stator coil may be more boosted.
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments and together with the description serve to explain the principles of the invention.
In the drawings:
FIG. 1 is a perspective view illustrating an electric motor according to one embodiment of the present invention;
FIG. 2 is a front view of FIG. 1;
FIG. 3 is a side view of FIG. 1;
FIG. 4 is a perspective view illustrating the inside of a case of FIG. 1;
FIG. 5 is a cross-sectional view of FIG. 1;
FIG. 6 is an exploded perspective view of FIG. 1;
FIG. 7 is a cross-sectional view taken along line VII-VII of FIG. 2;
FIG. 8 is a perspective view illustrating the inside of a case of FIG. 6;
FIG. 9 is a planar elevation view illustrating an outer rib and an inner rib of FIG. 8;
FIG. 10 is a cross-sectional view illustrating an inner rib of FIG. 9;
FIG. 11 is an exploded perspective view illustrating an electric motor according to another embodiment of the present invention;
FIG. 12 is a planar view illustrating an inner side of a cooling path cover of FIG. 11;
FIG. 13 is a perspective view illustrating an oil feeding portion of FIG. 1;
FIG. 14 is a perspective view illustrating an oil cooling grill of FIG. 1;
FIG. 15 is a cross-sectional view illustrating a cooling plate taken along line XV-XV of FIG. 14;
FIG. 16 is a cross-sectional view illustrating an oil cooling grill taken along line XVI-XVI of FIG. 15;
FIG. 17 is an enlarged cross-sectional view illustrating a main part of FIG. 16;
FIG. 18 is an enlarged view illustrating an oil guide area of FIG. 5;
FIG. 19 is a cross-sectional view illustrating an electric motor according to still another embodiment of the present invention;
FIG. 20 is a control block view illustrating an electric motor of FIG. 19;
FIG. 21 is a cross-sectional view illustrating an electric motor according to further still another embodiment of the present invention;
FIG. 22 is an enlarged view illustrating a main part of FIG. 21;
FIG. 23 is a front view illustrating a radiating fin of FIG. 21;
FIG. 24 is a partially enlarged view illustrating an area where a heat pipe of FIG. 21 is installed; and
FIGS. 25 and 26 are views illustrating modified examples of a heat pipe of FIG. 21.
Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts, and their description will be replaced with first description. The singular expression used in this specification includes the plural expression unless mentioned otherwise on the context. Also, in the description of the embodiments disclosed in this specification, if detailed description of elements or functions known in respect of the present invention is determined to make the subject matter of the embodiments disclosed in this specification unnecessarily obscure, the detailed description will be omitted. Also, it is to be understood that the accompanying drawings are only intended to facilitate understanding the embodiments disclosed in this specification, and it is not to be understood that technical spirits disclosed in this specification should be restricted by the accompanying drawings.
As shown in FIGS. 1 to 5, an electric motor according to one embodiment of the present invention includes a case 110 forming a receiving space therein, a stator 130 received in the case 110, a rotor 160 performing relative motion with respect to the stator 130, and a cooling path portion 190 forming a path 198 of a cooling fluid on an outer surface of the case 110. The cooling path portion 190 may include an outer rib 192 projected toward the outer surface of the case 110 and extended along a circumferential direction to form the receiving space of the cooling fluid therein, inner ribs 195 projected from the outer surface of the case 110 at an inner side of the outer rib 192, extended axially, and spaced apart from one another along a circumferential direction to form the path 198 of the cooling fluid, and a path formation cover or cooling path cover 210 (hereinafter, referred to as 'cooling path cover 210') arranged along a radius direction of the case 110 to block the outsides of the outer rib 192 and the inner rib 195 to form the path 198 of the cooling fluid together with the outer rib 192 and the inner rib 195.
The case 110 may be provided in a cylindrical shape.
For example, the case 110 may include a cylindrical portion 112 forming a cylindrical receiving space of which both sides are opened, and a bracket 114 coupled to both ends of the cylindrical portion 112.
The case 110 may be formed of a metal member, for example.
The stator 130 and the rotor 160 may be provided inside the case 110.
The stator 130 may include a stator core 131 provided with a plurality of slots 133, and a stator coil 141 wound in the stator core 131.
The stator core 131 may be formed by insulating and depositing a plurality of electric steels 132, for example.
A rotor receiving hole 134 for rotatably receiving the rotor 160 may be provided at the center of the electric steels 131 of the stator core 131.
The slots 134 may be formed to be circumferentially spaced apart from one another around the rotor receiving hole 134.
The rotor 160 may include, for example, a rotor core 161, and a rotor coil 171 wound in the rotor core 161.
A rotation shaft 165 is coupled to the center of the rotor core 161.
The rotation shaft 165 may be provided with a hollow portion 166 which passes through along an axis center.
Both sides of the rotation shaft 165 may rotatably be supported.
The rotation shaft 165 may rotatably be supported by a bearing 167 provided in the bracket 114.
As shown in FIG. 6, an oil seal 168 may be provided at one side of the bearing 167 to prevent cooling oil 231, which will be described later, from leaking out.
Meanwhile, the electric motor according to this embodiment may include a power supply portion 180 for supplying a power source to the rotor coil 171.
The power supply portion 180 may include, for example, a slip ring 184 rotated by being coupled to the rotation shaft 165, and a brush 186 which is electrically in contact with the slip ring 184.
For example, the power supply portion 180 may be provided outside or inside the case 110.
In this embodiment, the power supply portion 180 is provided inside the case 110. However, the power supply portion 180 may be provided outside the case 110.
The power supply portion 180 may further include, for example, a power supply case 182 surrounding the slip ring 184 and the brush 186.
The power supply case 182 may be configured in such a manner that the inside and the outside of the power supply case 182 are disconnected from each other hermetically.
That is, the power supply case 182 may be configured such that gaseous transport between the inside and the outside may be restricted.
As a result, if the cooling oil 231 which will be describe later is injected into the case 110, the power supply case 182 may prevent the cooling oil 231 from accessing the slip ring 184.
In this embodiment, a field winding type rotor provided with the rotor coil 171 is used as the rotor 160. This embodiment is only exemplary, and an induction type rotor provided with a conducting bar inserted into the rotor core and a short-circuit ring connecting with the conducting bar may be used as the rotor 160 in another embodiment.
Also, in still another embodiment, it will be apparent that a permanent magnet type rotor provided with a permanent magnet coupled to and/or inserted into the rotor core may be used as the rotor.
Meanwhile, a cooling path portion 190 for forming the path 198 of the cooling fluid may be provided on the outer surface of the case 110.
The cooling path portion 190, as shown in FIGS. 7 to 9, may include an outer rib 192 projected toward the outer surface of the case 110 and extended along a circumferential direction to form the receiving space of the cooling fluid therein, inner ribs 195 projected from the outer surface of the case 110 at an inner side of the outer rib 192, extended axially, and spaced apart from each other along a circumferential direction to form the path 198 of the cooling fluid, and a cooling path cover 210 arranged along a radius direction of the case 110 to block the outsides of the outer rib 192 and the inner rib 195 to form the path 198 of the cooling fluid together with the outer rib 192 and the inner rib 195.
The outer rib 192 may include, for example, circumferential section portions 193a outwardly projected from the outer surface of the case 110 toward the outside, extended along a circumferential direction and spaced apart from one another along an axial direction, and connecting section portions 193b connecting both ends of the circumferential section portions 193a with each other.
The outer rib 192 may be provided, for example, in a rectangular ring shape.
The connecting section portions 193b may respectively be arranged, for example, along the axial direction.
The inner rib 195 has a length reduced as compared with a distance between the circumferential section portions 193a, and may be configured in such a manner that its one end is connected to any one of the circumferential section portions 193a and its other end is spaced apart from the other one of the circumferential section portions 193a to form a communication portion 197 between the other end of the inner rib 195 and the other one of the circumferential section portions 193a to move the cooling fluid therebetween.
Each of the outer rib 192 and the inner rib 195 may be formed in such a manner that its sectional area is reduced gradually along the projected direction.
In more detail, as shown in FIG. 10, the inner rib 195 (for example, second rib 196g) may be configured in such a manner that the inner rib 195 has a maximum width w1 at the end connected with the outer surface of the case 110 and a minimum width w2 at the projected end as its width is reduced gradually along the projected direction.
The end surface of each of the outer rib 192 and the inner rib 195 may have a planarization surface.
As a result, the end surface of each of the outer rib 192 and the inner rib 195 may be in surface contact with the cooling path cover 210, whereby the cooling fluid inside the cooling path cover 210 may effectively be prevented from leaking out.
The circumferential section portions 193a of the outer rib 192 may be provided in a substantially arc shape.
The circumferential section portions 193a of the outer rib 192 may have a length reduced as compared with the circumference of the cylindrical portion 112.
The circumferential section portions 193a of the outer rib 192 may have a length reduced as compared with a circumference of the cylindrical portion 112.
The circumferential section portions 193a of the outer rib 192 may have a length greater than a half of the circumference of the cylindrical portion 112.
The circumferential section portions 193a of the outer rib 192 may have a length in such a manner that both ends may respectively be arranged below a horizontal center line of the case 110.
The connecting section portions 193b of the outer rib 192 may respectively be arranged below the horizontal center line of the case 110.
The inner rib 195 may include, for example, first to thirteenth ribs 196a to 196m of which one ends are connected to the circumferential section portion 193a of one side along the axial direction and the other ends are spaced apart from the circumferential section portion 193a of one side.
In this embodiment, the inner rib 195 arranged at one side (upper side) of the connecting section portion 193b at a right side on the drawing, having one end formed to be connected with the circumferential section portion 193a at the front is the first rib 196a, and the inner rib 195 arranged at one side (upper side) of the first rib 196a along the circumferential direction, having an end connected to the circumferential section portion 193a at the rear on the drawing and spaced apart from the circumferential section portion 193a at the front is the second rib 196b.
In this way, the odd numbered ribs of the inner ribs 195 are connected with the circumferential section portion 193a at the front to form the communication portion 197 at the rear, and the even numbered ribs of the inner ribs 195 are connected with the circumferential section portion 193a at the rear to form the communication portion 197 at the front.
In other words, the first rib 196a, the third rib 196c, the fifth rib 196e, the seventh rib 196g, the ninth rib 196i, the eleventh rib 196k and the thirteenth rib 196m are connected with the circumferential section portion 193a at the front on the drawing, and their rear ends are spaced apart from the circumferential section portion 193a at the rear, whereby the communication portion 197 may be formed between each of the rear ends of the ribs and the circumferential section portion 193a at the rear.
Also, the second rib 196b, the fourth rib 196d, the sixth rib 196f, the eighth rib 196h, the tenth rib 196j and the twelfth rib 196e are connected with the circumferential section portion 193a at the rear and spaced apart from the circumferential section portion 193a at the front, whereby the communication portion 197 may be formed between each of the ribs and the circumferential section portion 193a at the front.
According to this configuration, a single path 198 may be formed at the inner side of the outer rib 192, and in the path 198, for example, a first section 199a of the path 198 of the cooling fluid may be formed between the connecting section portion 193b and the first rib 196a, and a second section 199b of the path 198 may be formed between the first rib 196a and the second rib 196b.
Also, a third section 199c of the path 198 may be formed between the second rib 197b and the third rib 196c, and a fourth section 199d may be formed between the third rib 196c and the fourth rib 196d.
In this way, fifth to thirteenth sections 199e to 199m of the path 198 may respectively be formed between the fourth rib 196 and the thirteenth rib 196m, and a fourteenth section 199n of the path 198 may be formed between the thirteenth rib 196m and the connecting section portion 193b.
The first to fourteenth sections 199a to 199n of the path 198 may respectively be communicated with one another by the communication portions 197 formed between the first to thirteenth ribs 196a to 196m and the circumferential section portions 193a.
In this embodiment, the first to thirteenth ribs 196a to 196m are arranged inside the outer rib 192. However, the number of the inner ribs 195, the spacing of the inner ribs 195, and the projected length (height) of each rib may be controlled appropriately considering radiating capacity of the stator 130 and the rotor 160.
In this embodiment, the outer rib 192 is formed at some area of the circumference of the case 110 along the circumferential direction of the case 110. However, this embodiment is only exemplary, and the outer rib 192 of the cooling path portion 190 may be formed over almost of the circumference along the circumferential direction of the case 110.
Also, in this embodiment, the outer rib 192 is provided with two circumferential section portions 193a and two connecting section portions 193b to form a single ring shape so that the single path 198 of the cooling fluid is formed therein. However, this embodiment is only exemplary, and a plurality of outer ribs may be provided on the outer surface of the case 110, whereby paths of cooling fluid may be formed independently inside each of the outer ribs.
Also, the inside of the single outer rib 192 may be partitioned into a plurality of spaces which are independent from one another, and a plurality of inner ribs may be arranged inside each partitioned space, whereby a plurality of paths of the cooling fluid may be formed in parallel.
In more detail, the inner rib 195, for example, the length of the seventh rib 196g may be extended such that both ends may respectively be connected with the two circumferential section portions 193a to partition the inside of the seventh rib 196g into two spaces spaced apart from each other, and the first to sixth ribs 196a to 196f may be arranged inside the space at one side and the eighth to thirteenth ribs 196h to 196m may respectively be arranged inside the space at the other side, whereby two paths of the cooling fluid may be arranged in parallel at both ends of the second rib 196g.
Meanwhile, the cooling path cover 210 may be provided in an arc shape.
The cooling path cover 210 is arranged in such a manner that its inner surface is in contact with the outer rib 192 and the inner rib 105, whereby open sides (outsides) of the outer rib 192 and the inner rib 195 may be blocked.
A mutual contact area between the cooling path cover 210 and the outer rib 192 may be provided with a sealing member 216 to prevent the cooling fluid from leaking out.
The cooling path cover 210 may be coupled to the case 110 in a single piece by a plurality of fastening members 214, for example.
The fastening members 214 may be comprised of, for example, bolts or screws that may be coupled to the case 110.
The cooling path cover 210 may be provided with a fastening member insertion hole 212 into which the fastening member may be inserted.
The case 110 may be provided with female screws 215 to which the fastening members 214 may be coupled.
The female screws 215 may respectively be formed at the outer rib 192 and/or the inner rib 195.
The outer rib 192 may be provided with an inlet portion 222 that may flow the cooling fluid into the outer rib 192.
The outer rib 192 may be provided with an outlet portion 224 that may flow the cooling fluid inside the outer rib 192 out.
The inlet portion 222 and the outlet portion 224 may respectively be formed to pass through the circumferential section portions 193a of the outer rib 192.
In more detail, the inlet portion 222 may be formed at one end of the circumferential section portion 193a of the outer rib 192, and the outlet portion 224 may be formed at the other end of the circumferential section portion 193a of the outer rib 192.
For example, the inlet portion 222 may be formed at a first end (right end) of the circumferential section portion 193a at the front on the drawing, and the outlet portion 224 may be formed at a second end (left end) of the circumferential section portion 193a at the front on the drawing.
Each of the inlet portion 222 and the outlet portion 224 may be provided with a connecting member 225 that may be connected with each of cooling fluid pipes 228 and 229.
Each connecting member 225 may include, for example, an insertion portion 226 inserted into each of the inlet portion 222 and the outlet portion 222 for communication with each of the inlet portion 222 and the outlet portion 224, and an extension portion 227 extended by being bent from the insertion portion 226.
For example, each extension portion 227 may be configured to be extended by being bent toward the upper side of the case 110.
Meanwhile, FIG. 11 is an exploded perspective view illustrating an electric motor according to another embodiment of the present invention, and FIG. 12 is a planar elevation view illustrating an inner side of a cooling path cover of FIG. 11.
As shown in FIG. 11, a plurality of inner ribs 195 projected along a radius direction and extended axially may be provided on the outer surface of the case 110.
The inner ribs 195 may be formed in a single piece when the case 110 is formed.
The inner ribs 195 may be arranged in a zigzag shape to form the communication portion 197 at one side as described above.
The case 110 may be formed by extrusion, for example.
As a result, mass production of the case 110 may be made, whereby the manufacturing cost may be reduced.
For example, the cooling path cover 210 may be provided with the outer ribs 192 formed in a single piece.
The outer ribs 192 may include, for example, circumferential section portions 193a arranged along the circumferential direction of the cooling path cover 210 and connecting section portions 193b connecting the circumferential sections 193a with each other, as shown in FIG. 12.
The sealing member 216 may be provided at the end of the outer rib 192.
In this case, the sealing member 216 is in contact with the outer surface of the case 110 when the cooling path cover 210 is coupled to the case 110, whereby the cooling fluid inside the case 110 may be prevented from leaking out.
The sealing member 216 may have a rectangular ring shape to correspond to the shape of the outer rib 192.
The outer rib 192 may be provided with the inlet portion 22 for inflow of the cooling fluid and the outlet portion 224 for outflow of the cooling fluid.
In this embodiment, the outer rib 192 is provided in the cooling path cover 210. However, the outer rib 192 and the inner ribs 195 may be provided inside the cooling path cover 210.
Also, the inner rib 195 may be provided inside the cooling path cover 210, and the outer rib 192 may be formed separately from the case 110 and the cooling path cover 210 and then coupled to the case 110 and the cooling path cover 210.
Also, the connecting section portions 193b of the inner rib 195 and the outer rib 192 may be formed in a single piece on the outer surface of the case 110, and the circumferential section portions 193a of the outer rib 192 may be formed in the cooling path cover 210.
Meanwhile, the cooling oil 231 may be injected into the case 110.
It is preferable that the cooling oil 231 has excellent flexibility at a low temperature and has excellent heat resistance and excellent oxidation resistance.
For example, transmission oil of a vehicle may be used as the cooling oil 231.
The cooling oil 231 may be filled with a height or more of oil that may simultaneously be in contact with a part of the inside of the case 110, a part of the stator 130 and a part of the rotor 160.
Therefore, heat exchange among the case 110, the stator 130 and the rotor 160 may be boosted.
For example, it is preferable that the cooling oil 231 has an oil height higher than a bottom surface of a coil end 172 of the rotor coil 171 arranged at a lower portion on the drawing (sectional view), whereby the cooling oil 231 may be filled in the case 110.
As a result, a part of the inside of the case 110, a part of the stator 130 and a part of the rotor 160 may simultaneously be in contact with the cooling oil 231.
Preferably, the cooling oil 231 may be filled in the case 110 such that its height may be formed between a lower end surface and an upper end surface of the coil end 172 of the rotor coil 171.
An oil cooling portion 240 for cooling of the cooling oil 231 may be provided.
The oil cooling portion 240 may include, for example, a pass-through portion 245 formed to pass through the case 110, and an oil cooling grill 250 coupled to the pass-through portion 245 such that one side is in contact with oil inside the case 110 and the other side is in contact with the external air of the case 110.
An oil receiving portion 241 in which the cooling oil 231 is temporarily received may be provided at the bottom of the case 110.
For example, the oil receiving portion 241 may be formed to be projected toward one side at the lower portion of the case 110.
The oil receiving portion 241 may be formed in a horizontal direction (for example, vertical direction) with respect to the axial direction.
The oil receiving portion 241 may be provided in a rectangular sectional shape, for example.
The pass-through portion 245 may be formed to be opened in a rectangular shape at the end where the oil receiving portion 241 is projected.
The oil receiving portion 241 may have a circumferential shape portion 243 having a curvature radius corresponding to an inner diameter surface of the case 110.
A circumferential opening 246 may be formed at an inner area (the circumferential shape portion 243) of the oil receiving portion 241 to communicate with the inside of the case 110.
A bottom opening 248 may be formed at the bottom surface of the oil receiving portion 241.
The oil cooling grill 250 may include, for example, as shown in FIGS. 12 to 15, a grill body 252 coupled to the pass-through portion 245, and cooling plates 261 projected from the grill body 252, in contact with the oil inside the case 110 through the pass-through portion 245, and spaced apart from one another at a predetermined distance.
For example, the grill body 252 may be configured to block the pass-through portion 245 and the bottom opening 248.
The grill body 252 may include a vertical block portion 254 for blocking the pass-through portion 245.
The vertical block portion 254 may have, for example, a rectangular plate shape greater than the pass-through portion 245.
A sealing member 258 for preventing the oil 231 from leaking out may be provided between the vertical block portion 254 and the pass-through portion 245.
The grill body 252 may include, for example, a horizontal block portion 256 for blocking the bottom opening 248.
The horizontal block portion 256 may be projected from the bottom of the vertical block portion 254 toward a horizontal direction and may have a rectangular plate shape.
The sealing member 258 for preventing the oil 231 from leaking out may be provided at a mutual contact area between the horizontal block portion 256 and the bottom of the oil receiving portion 241.
The cooling plates 261 may be projected from the grill body 252 and may be spaced apart from one another at a predetermined interval.
Therefore, each cooling plate 261 may be inserted into the oil receiving portion 241 through the pass-through portion 245.
For example, each cooling plate 261 may be configured to include an arc shaped end portion 264 having a curvature radius corresponding to the inner diameter surface of the case 110.
Each cooling plate 261 may be formed to include an air path 263 cut in a thickness direction to move the air therethrough.
In more detail, each cooling plate 261 has a predetermined thickness, and the air path 263 may be cut inwardly along a plate surface direction from one side end to have a width (thickness) more reduced than the thickness of each cooling plate 261.
The air path 263 of each cooling plate 261 may be formed to open an end portion and a bottom portion at the pass-through portion 245 of each cooling plate 261.
That is, the air path 263 has a channel (U section) shape surrounded by an upper end surface 262a, both side walls 262b and the arc shaped end portion 264 of each cooling plate 261.
The electric motor according to this embodiment may be installed to be arranged in parallel with a moving direction of a vehicle. In this case, the pass-through portion 245 may be arranged at a front end portion of the moving direction. Therefore, the end portion at the pass-through portion 245 of each cooling plate 261 is arranged at the forefront with respect to the moving direction of the vehicle, whereby the end portion becomes an inlet of the air path 263, and the bottom side of the cooling plate 261 may be an outlet of the air path 263.
Meanwhile, the rotor 160 may be provided with an oil feeding portion 280 for feeding the oil accommodated in a lower side of the case 110 to an upper portion when the rotor 160 is rotated.
As a result, a contact between the oil 231 inside the case 110 and the stator 130 and a contact between the oil 231 and the rotor 160 are increased (boosted), whereby heat exchange between the stator 130 and the oil 231 and between the rotor 160 and the oil 231 may be boosted.
According to this configuration, local temperature increase of the stator 130 and the rotor 160, which are heat sources, may be reduced remarkably.
In more detail, the coil end 142 of the stator coil 141 is in contact with the air inside the case 110 of which heat transfer is relatively insufficient than the stator coil 131 which is in contact with the case 110 to enable heat transfer, radiating is insufficient. For this reason, local temperature increase of the coil end 142 of the stator coil 141 is generated. In general, if the temperature of the coil end 142 of the stator coil 141 is increased excessively, electric resistance of the stator coil 141 is increased, whereby magnetic flux is reduced. For this reason, output (performance) of the electric motor may be deteriorated.
As the oil 231 scattered by the oil feeding portion 280 is in contact with the coil end 142 of the stator coil 141, cooling of the coil end 142 of the stator coil 141 is boosted, whereby excessive temperature increase of the coil end 142 may be reduced.
As a result, local temperature increase of the coil end 142 of the stator coil 141 is reduced, whereby power density may be raised.
The oil feeding portion 280 may include, for example, as shown in FIG. 11, a disk shaped plate portion 282 and a plurality of blades 291 projected from the plate portion 282 and spaced apart from one another in a circumferential direction.
In more detail, each blade 291 may be configured to have a projection length axially projected from at least one surface of the plate portion and a width based on a radius direction.
For example, the axial projection length of each blade 291 may be configured at a length that may be outwardly projected to be smaller than (smaller width) the end portion of the stator coil 141.
As a result, the oil 231 may easily be scattered toward the inner diameter surface of the case 110.
The plate portion 282 may be provided with a support portion 284 projected to correspond to the width of each blade 291, having a ring shape.
An axial hole 285 that may receive the rotation shaft 165 therein may be formed in the plate portion 282 to pass through the plate portion 282.
A reinforcing rib 286 of which thickness is increased at a predetermined width in a circumferential direction and a radius direction may be provided around the axial hole 285.
The reinforcing rib 286 may include, for example, a circumferential rib 287 arranged in a circumferential direction and a radius rib 288 arranged in a radius direction.
Meanwhile, the case 110 may include, for example, as shown in FIG. 16, an oil guide 295 that guides the oil 231, which is moving upwardly, between the coil end 142 of the stator coil 141 and the inner diameter surface of the case 110.
The cooling oil 231 inside the case 110 may be fed to the upper area inside the case 110 by the oil feeding portion 280 when the rotor 160 is rotated.
For example, the oil guide 295 may be projected from the inner surface of the bracket 114 to arrange its projection end between the coil end 142 of the stator coil 141 and the cylindrical portion 112.
The oil guide 295 may be formed of a synthetic resin member or rubber member, for example.
The oil guide 295 may include a curvature shaped guide surface 297 surrounding the coil end 142 of the stator coil 141.
In this case, the oil guide 295 may be configured to have an arc shape to surround the coil end 142 of the upper area of the stator coil 141.
According to this configuration, if the electric motor is driven, a power source may be supplied to each of the stator 130 and the rotor 160.
If the power source is applied to each of the stator coil 141 and the rotor coil 171, magnetic flux is generated in each of the stator coil 141 and the rotor coil 171, whereby the rotor 160 may be rotated based on the rotation shaft 165 by attraction and/or repulsion between the stator coil 141 and the rotor coil 171.
If the power source is supplied to each of the stator coil 141 and the rotor coil 171, each temperature of the stator coil 141 and the rotor coil 171 may be increased by heating.
The heat generated by the stator coil 141 may be transferred to the stator coil 131, and the heat generated by the stator core 131 may be transferred to the case 110.
The heat generated by the rotor coil 171 may be transferred to the rotor core 161.
Meanwhile, if the electric motor is driven, the cooling fluid may be supplied to the cooling path portion 190.
In more detail, the cooling fluid flowing through the inlet portion 222 may be heat-exchanged with the case 110 by sequentially passing through the first section 199a to the fourteenth section 199n of the path.
As a result, the case 110 may be cooled, and each of the stator core 131 and the stator coil 141, which are in contact with the case 110 to enable heat transfer, may be cooled.
The cooling fluid moving along the first section 199a to the fourteenth section 199n of the path may be subjected to outflow through the outlet portion 224.
The oil feeding portion 280 may be rotated in a single piece with the rotation shaft 165 when the rotor 160 is rotated.
The blade 291 disposed at a lower side of the oil feeding portion 280 is immersed inside (below oil scum) the oil, and rises above the surface of the oil 231 during rotation.
At this time, the blade 291 upwardly pressurizes the oil 231 and the oil 231 attached to the surface of the blade 291 may be scattered outwardly by a centrifugal action.
As a result, circulation of the cooling oil 231 inside the case 110 may be boosted.
The oil 231 scattered by the oil feeding portion 280 is in contact with each of the coil end 142 of the stator coil 141 and the inner diameter surface of the case 110, whereby heat exchange may be made.
In more detail, the oil 231 which is in contact with the coil end 142 of which temperature is relatively high cools the coil end 142, and the oil 231 which is in contact with the case 110 of which temperature is relatively low may be cooled by heat-exchange with the case 110.
That is, the oil 231 repeatedly performs a process of cooling the coil end 142 of which temperature is higher than the temperature of the oil 231 and a process of being cooled by the case 110 of which temperature is lower than the temperature of the oil 231 while circulating the inside of the case 110, thereby boosting heat exchange between the respective components.
The oil feeding portion 280 may prevent a local temperature from rising by boosting circulation of the oil 231 while rotating together with the rotor 160 when the rotor 160 is rotated and boosting heat exchange between a high temperature area and a low temperature area inside the case 110 during driving.
The oil 231 scattered by the oil feeding portion 280 descends by mean of self load after heat exchange with another component, whereby the oil 231 is collected to a lower area inside the case 110, and is scattered to an upper area by the oil feeding portion 280. This process may be repeated.
Meanwhile, some of the oil 231 at a lower portion inside the case 110 may temporarily be received in the oil receiving portion 241 and then cooled therein.
The oil of the oil receiving portion 241 may be in contact with the oil cooling grill 250.
The oil of the oil receiving portion 241 may be in contact with each cooling plate 261 of the oil cooling grill 250.
The air may be supplied to the air path 263 of the cooling plate 261 of the oil cooling grill 250.
As a result, cooling of the oil may be boosted.
If a flow speed of the air supplied to the air path 263 is increased, cooling of the oil cooling grill 250 is boosted, whereby cooling of the oil may be more boosted.
For example, since the electric motor is arranged in parallel with a driving direction of a vehicle and the oil cooling grill 250 is arranged at a front area of the case 110 along the driving direction of the vehicle, the air of a relatively fast speed flows into and flows out of the air path 263 of each cooling plate 261 if the vehicle is driving, whereby cooling of the cooling plate 261 may be boosted and thus cooling of the oil may be boosted.
If the oil accommodated in the lower side of the case 110 is upwardly moved by rotation of the oil feeding portion 280, the oil cooled inside the oil receiving portion 241 flows out, and some of the oil of which temperature is increased by heat exchange at the upper area inside the case 110 may flow into the oil receiving portion 241 and may be cooled therein.
Meanwhile, the oil guide 295 may allow the oil fed upwardly by the oil feeding portion 280 to move between the outer surface of the coil end 142 of the stator coil 141 and the inner diameter surface of the case 110.
As a result, the outer surface of the coil end 142 of the stator coil 141, of which cooling is relatively insufficient as it is difficult for the oil to access the coil end 142 during rotation of the oil feeding portion 280, may easily be cooled.
Particularly, the oil guide 295 guides the oil 231 upwardly fed (scattered) by the oil feeding portion 280 to be in contact with the inner diameter surface of the case 110 of which temperature is relatively low, whereby the temperature of the oil 231 may be more lowered. As a result, a temperature difference between the oil 231 and the coil end 142 may be more increased, whereby the coil end 142 of the stator coil 141 may be cooled more effectively.
Meanwhile, FIG. 17 is a cross-sectional view illustrating an electric motor according to another embodiment of the present invention, and FIG. 18 is a control block view illustrating the electric motor of FIG. 17.
As shown in FIG. 17, the electric motor according to this embodiment may include a case 110 forming a receiving space therein, a stator 130 received in the case 110, a rotor 160 performing relative motion with respect to the stator 130, cooling oil 231 injected into the case 110, an oil cooling portion 240 cooling the cooling oil 231, and a cooling path portion 190 forming a path 198 of a cooling fluid on an outer surface of the case 110.
In this case, the cooling path portion 190 may include an outer rib 192 projected toward the outer surface of the case 110 and extended along a circumferential direction to form a receiving space of the cooling fluid therein, inner ribs 195 projected from the outer surface of the case 110 at an inner side of the outer rib 192, extended axially, and spaced apart from one another other along a circumferential direction to form the path 198 of the cooling fluid, and a cooling path cover 210 arranged along a radius direction of the case 110 to block the outsides of the outer rib 192 and the inner rib 195 to form the path 198 of the cooling fluid together with the outer rib 192 and the inner rib 195.
The outer rib 192 may be provided with an inlet portion 222 and an outlet portion 224, which are respectively intended for inflow and outflow of the cooling fluid.
The inner rib 195 may include, for example, first to thirteenth ribs 196a to 196m arranged inside the outer rib 192 and spaced apart from one another along a circumferential direction.
The path 198 of the cooling fluid may be configured to include a connecting section portion 193b of the outer rib 192 and first to fourteenth sections 199a to 199n formed by the first to thirteenth ribs 196a to 196m.
The cooling oil 231 may be injected into the case 110.
The rotor 160 may be provided with an oil feeding portion 280 for feeding the oil to an upper portion when the rotor 160 is rotated.
Meanwhile, the oil cooling portion 240 may include, for example, an oil cooling path 302 through which the oil inside the case 110 is cooled while circulating via the outside of the case 110.
As a result, the cooling oil 231 is circulated via the outside of the case 110 of which temperature is relatively lower than the temperature of the inside of the case 110, of which temperature is increased during driving, whereby the coil 231 may be cooled.
The oil cooling path 302 may be configured in such a manner that an oil outlet portion 303 is formed at the bottom of the case 110 to flow out the oil and an oil inlet portion 304 is formed above the oil outlet portion 303 to flow the oil into the case 110.
In this case, the oil of which temperature is relatively increased by being moved to the upper area by the oil feeding portion 280 and heat- exchanged there may be cooled by flowing out of the case 110.
The oil cooling portion 240 may further include an oil pump 311 provided at the oil cooling path 302 to circulate the oil.
Therefore, circulation of the cooling oil 231 via the outside of the case 110 of which temperature is relatively low is boosted, whereby cooling of the oil 231 may be boosted.
The oil cooling path 302 may further include an oil heat exchanger 315 for allowing the oil flowing out of the case 110 to be subjected to heat exchange with the air or water.
In this case, the cooling of the cooling oil 231 may be more boosted.
The oil heat exchanger 315 may include, for example, an oil pipe 316 through which the oil flows.
The oil pipe 316 of the oil heat exchanger 315 may be provided in a zigzag shape, for example.
The oil pipe 316 of the oil heat exchanger 315 may further include, for example, a radiating fin 317 that may increase a heat exchange area of the oil pipe 316.
A cooling fan 320 for cooling the oil heat exchanger 315 by forcibly sending the air to the oil heat exchanger 315 may be provided at one side of the oil heat exchanger 315.
The oil cooling portion 240 may be configured to include the aforementioned oil cooling grill 250.
The case 110 may be provided with an oil guide 295 that guides the oil moved by the oil feeding portion 280 between the coil end 142 of the stator coil 141 and the inner diameter surface of the case 110.
Meanwhile, the electric motor of this embodiment may include, for example, a controller 330 for boosting cooling of the oil 231 by sensing the temperature of the oil 231.
A temperature sensing portion 335, which senses the temperature of the cooling oil 231, may be connected to the controller 330 to enable communication.
The oil pump 311 may be connected with the controller 330 to be controlled by the controller 330, thereby boosting circulation of the cooling oil 231.
The cooling fan may be connected with the controller 330 to be controlled by the controller 330, thereby boosting cooling of the oil if the temperature of the oil is a predetermined temperature or more.
In accordance with the above configuration, if the power source is applied to the stator 130 and the rotor 160 as driving of the electric motor is initiated, temperatures of the stator coil 141 and the rotor coil 171 may be increased respectively.
The cooling fluid may be supplied to the cooling path portion 190 to cool the case 110.
If the rotor 160 is rotated, the oil feeding portion 280 is rotated to upwardly fed the oil at the bottom of the case 110.
The oil scattered by the oil feeding portion 280 may descend by means of self load after being in contact with the stator coil 141 and the case 110 and then being heat-exchanged therewith.
The oil may be cooled by the oil cooling grill 250 of the oil receiving portion 241.
As a result of the temperature of the oil 231 sensed by the temperature sensing portion 335, if the cooling oil 231 is a predetermined temperature or more, the controller 330 may allow the oil inside the case 110 to circulate along the oil cooling path 302 by driving the pump.
The oil flowing out of the case 110 through the oil outlet portion 303 may be cooled while passing through the oil heat exchanger 315.
The oil cooled by the oil heat exchanger 315 may flow into the case 110 through the oil inlet portion 304.
Meanwhile, cooling of the oil by means of the oil cooling grill 250 and/or the oil heat exchanger 315 may be insufficient due to speed reduction and/or stop of the vehicle.
As a result of the temperature of the oil 231 sensed by the temperature sensing portion 335, if the oil 231 is a predetermined temperature or more, the controller 330 may allow the cooling fan 320 to be rotated.
The oil flowing out of the case 110 and moving along the oil cooling path 302 may be cooled by being heat exchanged with the air, which is forcibly ventilated by the cooling fan 320, at the oil heat exchanger 315.
Meanwhile, FIG. 19 is a cross-sectional view illustrating an electric motor according to still another embodiment of the present invention, FIG. 20 is an enlarged view illustrating a main part of FIG. 19, FIG. 21 is a front view illustrating a radiating fin of FIG. 19, FIG. 22 is a partially enlarged view illustrating that a heat pipe of FIG. 19 is installed, and FIGS. 23 and 24 are modification examples of the heat pipe of FIG. 19.
As illustrated in FIG. 19, the electric motor of this embodiment may include a case 110 forming a receiving space therein, a stator 130 received in the case 110, a rotor 160 performing relative motion with respect to the stator 130, a cooling path portion 190 forming a path 198 of a cooling fluid on an outer surface of the case 110, and a heat pipe 350 having one end which is in contact with the stator 130 and the other end which is exposed to the outside of the case 110 to radiate heat of the stator 130 to the outside of the case 110.
As described above, the cooling path portion 190 may include an outer rib 192 projected toward the outer surface of the case 110 and extended along a circumferential direction to form a receiving space of the cooling fluid therein, inner ribs 195 projected from the outer surface of the case 110 at an inner side of the outer rib 192, extended axially, and spaced apart from one another other along a circumferential direction to form the path 198 of the cooling fluid, and a cooling path cover 210 arranged along a radius direction of the case 110 to block the outsides of the outer rib 192 and the inner rib 195 to form the path 198 of the cooling fluid together with the outer rib 192 and the inner rib 195.
The electric motor according to this embodiment may include cooling oil 231 injected into the case 110.
An oil cooling portion 240 for cooling the cooling oil 231 may be provided at one side of the case 110.
An oil receiving portion 241 may be formed at one side of the case 110.
The oil cooling portion 240 may include an oil cooling grill 250 having one side which is in contact with the oil inside the case 110 and the other side which is in contact with the air outside the case 110.
The rotor 160 may be provided with an oil feeding portion 280 for upwardly feeding the cooling oil 231 during rotation.
Meanwhile, the electric motor of this embodiment may include a heat pipe 350 for radiating heat of the stator 130 from the outside of the case 110.
The heat pipe 350 may include, for example, a vessel 352 forming a sealing space, a working fluid 354 received in the vessel 352, and a wick 356 moving the working fluid 354 in accordance with a capillary phenomenon.
The vessel 352 of the heat pipe 350 may include, for example, a circular pipe shape.
The working fluid 354 may be comprised of, for example, a phase transformation material.
Preferably, the working fluid 354 may be comprised of a phase transformation material of which freezing point is relatively low.
For example, the working fluid 350 may be comprised of a refrigerant used for a vapor compression type cooling cycle.
The wick 356 may be formed of a mesh member, for example.
The wick 356 may be comprised of a groove formed to be recessed inside the vessel 352.
One end of the heat pipe 350 may be arranged to be in contact with the outer surface of the coil end 142 of the stator coil 141.
The other end of the heat pipe 350 may be ejected toward the outside of the case 110, for example.
For example, the other end of the heat pipe 350 may be arranged to be outwardly projected (extended) along a length direction of the case 110 by passing through the bracket 114.
A plurality of heat pipes 350 may be provided.
The plurality of heat pipes 350 may be arranged to be spaced apart from one another along a circumferential direction of the stator 130.
The number of heat pipes 350 and a spacing distance of the heat pipes 350 may be controlled appropriately considering heating capacity of the stator 130 and/or the rotor 160.
A radiating fin 361 may be provided at an exposed end of the heat pipe 350 to boost heat exchange.
The radiating fin 361 may have an arc shape, for example.
For example, the radiating fin 361 may have an arc shape extended along a circumferential direction, whereby the plurality of heat pipes 350 may simultaneously be combined with the radiating fin 361.
A plurality of radiating fins 361 may be provided.
The plurality of radiating fins 361 may be spaced apart from one another at a predetermined spacing along a length direction of the heat pipe 350.
Meanwhile, a heat conductive member 371 that enables heat conduction may be provided between the coil end 142 of the stator coil 141 and the heat pipe 350.
In this case, heat exchange between the coil end 142 of the stator coil 141 and the heat pipe 350 may be boosted.
The heat conductive member 371 may have, for example, an arc shape having a curvature radius corresponding to an outer diameter surface of the coil end 142, whereby the heat conductive member 371 may be in surface contact with the coil end 142 of the stator coil 141.
The heat conductive member 371 may have, for example, a length extended along a circumferential direction, whereby the heat conductive member 371 may be in contact with the plurality of heat pipes 350.
Of course, the length of the heat conductive member 371 may be controlled appropriately.
A heat transfer material (for example, thermal compound or thermal grease) 373 may be inserted between the heat conductive member 371 and the coil end 142 to boost heat transfer between the heat conductive member 371 and the coil end 142.
As a result, the amount of the air between the heat conductive member 371 and the coil end 142 may be reduced, whereby heat transfer may be boosted.
A periphery (for example, open area) of the heat transfer material 373 may be sealed to prevent the heat transfer material 373 from being lost, or may be treated to prevent the heat transfer material 373 from being lost.
Meanwhile, the heat pipe 350 may include, for example, as shown in FIG. 23, a heat conducting portion 381a having one end connected to the heat pipe 350 and the other end which is in contact with the coil end 142 of the stator coil 141 to enable heat transfer.
For example, the heat conducting portion 381a may be formed in a single piece with the vessel 352 of the heat pipe 350.
For example, the heat conducting portion 381a may include an arc type contact surface 383 to be in surface contact with an outer surface of the coil end 142 of the stator coil 141.
As a result, a contact area between the coil end 142 of the stator coil 141 and the vessel 352 is increased, whereby heat exchange with the working fluid 354 may be boosted.
The heat conducting portion 381a may be configured to have an arc shape.
In this embodiment, the heat conducting portion 381a is formed in a single piece with the vessel 352 of the heat pipe 350. However, this embodiment is only exemplary, and as shown in FIG. 24, a heat conducting portion 381b may be formed to have a length more extended along a circumferential direction, whereby the heat conducting portion 381b may simultaneously be connected with the vessel 352 of the plurality of heat pipes 350.
The heat conducting portion 381b may include, for example, an arc type contact surface 383 to be in surface contact with the outer surface of the coil end 142.
In accordance with the above configuration, if the power source is applied to the stator 130 and the rotor 160 as driving of the electric motor according to this embodiment is initiated, temperatures of the stator coil 141 and the rotor coil 171 may be increased respectively.
If driving of the electric motor is initiated, the cooling fluid may be supplied to the cooling path portion 190 to cool the case 110.
If the rotor 160 is rotated, the oil feeding portion 280 is rotated to upwardly feed the oil 231 at the bottom of the case 110.
The oil 231 scattered by the oil feeding portion 280 may descend by means of self load after being in contact with the stator coil 141 and the case 110 and then being heat-exchanged therewith.
Some of the oil 231 may be cooled by the oil cooling grill 250 of the oil receiving portion 241.
Meanwhile, the working fluid 354 inside the heat pipe 350 which is in contact with the coil end 142 of the stator coil 141 may be evaporated by absorbing latent heat in the periphery.
As a result, the coil end 142 of the stator coil 141 may be cooled quickly.
The working fluid 354 evaporated inside the vessel 352 of the heat pipe 350 may be moved to the exposed end (condensed portion) of the vessel 352.
The working fluid 354 moved to the exposed end of the heat pipe 350 may be condensed by being heat-exchanged (radiated) with the air outside the case 110.
At this time, the radiating fin 361 may boost radiating of the working fluid 354 evaporated inside the vessel 352 by boosting heat exchange between the air outside the case 110 and the vessel 352.
The radiated working fluid 354 inside the exposed end of the vessel 352 may be condensed again, and may be moved to an inner end (evaporating portion) of the heat pipe 350 by a capillary phenomenon of the wick 356.
The working fluid 354 inside the vessel 352 may cool the periphery by absorbing a periphery latent heat at the inner end (evaporating portion) of the vessel 352 during driving, and is radiated by being moved to the outside of the case 110, thereby continuously cooling the inside (especially, the coil end 142 of the stator coil 141) of the case 110 by repeating transfer of heat inside the case 110 to the outside of the case 110.
The foregoing embodiments and advantages are merely exemplary and are not to be considered as limiting the present disclosure. The present teachings can be readily applied to other types of apparatuses. This description is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments.
As the present features may be embodied in several forms without departing from the characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be considered broadly within its scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.

Claims (25)

  1. An electric motor comprising:
    a case forming a receiving space therein;
    a stator received in the case;
    a rotor performing relative motion with respect to the stator; and
    a cooling path portion forming a path of a cooling fluid on an outer surface of the case,
    wherein the cooling path portion includes:
    an outer rib projected toward the outer surface of the case and extended along a circumferential direction to form a receiving space of the cooling fluid therein;
    inner ribs projected from the outer surface of the case at an inner side of the outer rib, extended axially, and spaced apart from one another along a circumferential direction to form the path of the cooling fluid; and
    a cooling path cover arranged along a radius direction of the case to block the outsides of the outer rib and the inner rib to form the path of the cooling fluid together with the outer rib and the inner rib.
  2. The electric motor according to claim 1, wherein the outer rib includes circumferential section portions formed on the outer surface of the case along a circumferential direction and spaced apart from one another along an axial direction, and connecting section portions connecting both ends of the circumferential section portions with each other, and
    each of the inner rib has a length reduced as compared with a distance between the circumferential section portions, and its one end is connected to any one of the circumferential section portions and its other end is spaced apart from the other one of the circumferential section portions to form a communication portion to which the cooling fluid is moved.
  3. The electric motor according to claim 1, wherein the outer rib is provided with an inlet portion through which the cooling fluid flows into the outer rib, and an outlet portion through which the cooling fluid inside the outer rib flows out.
  4. The electric motor according to claim 1, wherein cooling oil is injected into the case.
  5. The electric motor according to claim 4, further comprising an oil cooling portion for cooling the oil.
  6. The electric motor according to claim 5, wherein the oil cooling portion includes a pass-through portion formed to pass through the case, and an oil cooling grill coupled to the pass-through portion, having one side which is in contact with the oil inside the case and the other side which is in contact with the air outside the case.
  7. The electric motor according to claim 6, wherein the oil cooling grill includes a grill body coupled to the pass-through portion, and cooling plates projected from the grill body, in contact with the oil inside the case through the pass-through portion, and spaced apart from one another at a predetermined distance.
  8. The electric motor according to claim 7, wherein each cooling plate is provided with an air path cut in a thickness direction to move the air therethrough.
  9. The electric motor according to claim 7, wherein an oil receiving portion for temporarily receiving the oil is formed at a lower side of the case, the pass-through portion is formed in the oil receiving portion, and the cooling plates are inserted into the oil receiving portion through the pass-through portion.
  10. The electric motor according to claim 9, wherein the outer rib is arranged above the pass-through portion.
  11. The electric motor according to claim 5, wherein the oil cooling portion includes:
    an oil cooling path through which the oil inside the case is cooled while circulating by passing through the outside of the case; and
    an oil pump provided in the oil cooling path to circulate the oil.
  12. The electric motor according to claim 11, wherein the oil cooling path is provided with an oil heat exchanger for heat-exchanging the oil ejected from the case with the air or water.
  13. The electric motor according to claim 4, further comprising an oil feeding portion provided in the rotor to feed the oil accommodated in a lower side of the case to an upper area when the rotor is rotated.
  14. The electric motor according to claim 13, wherein the oil feeding portion includes a plate portion having a disk shape and a plurality of blades projected from the plate portion and spaced apart from one another along a circumferential direction.
  15. The electric motor according to claim 14, wherein the stator includes a stator core, and a stator coil wound in the stator core, the electric motor further comprising an oil guide provided in the case to guide the oil, which is upwardly fed by the oil feeding portion when the rotor is rotated, between a coil end of the stator coil and the case.
  16. The electric motor according to claim 15, wherein the case includes a cylindrical portion and a bracket blocking both ends of the cylindrical portion, and the oil guide is projected from an inner surface of the bracket and has a projected end arranged between the coil end and the cylindrical portion.
  17. The electric motor according to any one of claims 1 to 14, further comprising a heat pipe having one end which is in contact with the stator and the other end which is exposed to the outside of the case to radiate heat of the stator to the outside of the case.
  18. The electric motor according to claim 17, further comprising a radiating fin coupled to the exposed end of the heat pipe.
  19. The electric motor according to claim 18, wherein the heat pipe is configured as a plurality of heat pipes spaced apart from one another along a circumferential direction of the case, and the radiating fin has an arc shape to be coupled to the heat pipes.
  20. The electric motor according to claim 17, wherein the stator includes a stator core and a stator coil wound in the stator core, and the heat pipe includes a heat conducting portion having one end connected to the heat pipe and the other end which is in contact with the coil end of the stator coil to enable heat transfer.
  21. The electric motor according to claim 17, wherein the stator includes a stator core and a stator coil wound in the stator core, the electric motor further comprising a heat conducting member inserted into between the coil end of the stator coil and the heat pipe to enable heat transfer.
  22. A method of manufacturing an electric motor, the method comprising the steps of:
    preparing a case that forms a receiving space therein;
    forming a cooling path portion that forms a path of a cooling fluid on an outer surface of the case;
    arranging a stator inside the case; and
    arranging a rotor, which performs relative motion with respect to the stator, inside the case,
    wherein the cooling path portion includes an outer rib projected toward the outer surface of the case and extended along a circumferential direction to form a receiving space of the cooling fluid therein, inner ribs projected from the outer surface of the case at an inner side of the outer rib, extended axially, and spaced apart from one another along a circumferential direction to form the path of the cooling fluid, and a cooling path cover arranged along a radius direction of the case to block the outsides of the outer rib and the inner rib to form the path of the cooling fluid together with the outer rib and the inner rib, and
    the step of forming the cooling path portion includes:
    forming the inner ribs on the outer surface of the case;
    forming the outer rib on an inner surface of the cooling path cover; and
    coupling the cooling path cover to the outer surface of the case to form the path of the cooling fluid.
  23. A method of manufacturing an electric motor, the method comprising the steps of:
    preparing a case that forms a receiving space therein;
    forming a cooling path portion that forms a path of a cooling fluid on an outer surface of the case;
    arranging a stator inside the case; and
    arranging a rotor, which performs relative motion with respect to the stator, inside the case,
    wherein the cooling path portion includes an outer rib projected toward the outer surface of the case and extended along a circumferential direction to form a receiving space of the cooling fluid therein, inner ribs projected from the outer surface of the case at an inner side of the outer rib, extended axially, and spaced apart from one another along a circumferential direction to form the path of the cooling fluid, and a cooling path cover arranged along a radius direction of the case to block the outsides of the outer rib and the inner rib to form the path of the cooling fluid together with the outer rib and the inner rib, and
    the step of forming the cooling path portion includes:
    forming the cooling path cover;
    forming the outer rib and the inner ribs on the outer surface of the case or an inner surface of the cooling path cover; and
    coupling the cooling path cover to the outer surface of the case to form the path of the cooling fluid.
  24. The method according to claim 22 to 23, wherein the step of forming the outer rib includes: forming an inlet portion through which the cooling fluid flows into the outer rib; and forming an outlet portion through which the cooling fluid inside the outer rib flows out.
  25. The method according to claim 22 to 23, further comprising the step of arranging a sealing member, which prevents the cooling fluid from leaking out, at a contact area between the cooling path cover and the case before the step of coupling the cooling path cover to the outer surface of the case.
PCT/KR2015/008697 2015-07-24 2015-08-20 Electric motor and manufacturing method thereof WO2017018578A1 (en)

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