WO2015024244A1

WO2015024244A1 - Motor with internal cooling

Info

Publication number: WO2015024244A1
Application number: PCT/CN2013/082148
Authority: WO
Inventors: Hanson XU; Wenbing Li; Paul S. Mullin; Edward L. Drye
Original assignee: Regal Beloit America, Inc.; Regal Beloit (Changzhou) Co., Ltd.
Priority date: 2013-08-23
Filing date: 2013-08-23
Publication date: 2015-02-26

Abstract

A motor includes a stator having a plurality of end coils. A control is coupled to a circuit board. The circuit board is coupled to the stator and is spaced apart from the end coils to define a first radial gap. A rotor is positioned adjacent the stator and is supported for rotation with respect to the stator. A fan is coupled to the rotor, and a housing surrounds and fully encloses the stator and the circuit board. The housing is spaced apart from the circuit board to define a first axial gap and a second radial gap. The fan directs a flow of cooling air through the first radial gap and the second radial gap to cool the circuit board.

Description

MOTOR WITH INTERNAL COOLING

BACKGROUND

[0001] The present invention relates to a cooling arrangement for a totally enclosed electric motor. More specifically, the present invention relates to a cooling arrangement for the printed circuit board of a totally enclosed electric motor.

[0002] Known totally enclosed motor constructions present challenges in maintaining acceptable temperatures for the internal components, particularly for the electronic control that is contained in the motor.

SUMMARY

[0003] In one construction, the invention provides a motor. The motor includes a stator having a plurality of end coils and a control coupled to a circuit board. The circuit board is coupled to the stator and is spaced apart from the end coils to define a first radial gap. A rotor is positioned adjacent the stator and is supported for rotation with respect to the stator. A fan is coupled to the rotor, and a housing surrounds and fully encloses the stator and the circuit board. The housing is spaced apart from the circuit board to define a first axial gap and a second radial gap. The fan directs a flow of cooling air through the first radial gapand the second radial gap to cool the circuit board.

[0004] In another construction, the invention provides a motor. The motor includes a stator having a first end with first end coils, a second end having second end coils, and an opening extending along a rotational axis between the first end and the second end. A housing surrounds and completely encloses the stator and includes a first end and a second end. The first end of the housing cooperates with the first end of the stator to define an axial space. A first support is coupled to the first end of the housing, and a second support is coupled to the second end of the housing. A rotor is positioned at least partially within the opening and is supported for rotation by the first support and the second support. A circuit board is coupled to the first end of the stator and is positioned within the axial space. A fan is coupled to the rotor and is disposed axially between the first end coils and the circuit board. The fan rotates in response to rotor rotation and is operable to draw air into an axial inlet and to discharge air radially to produce a continuous flow of cooling air around the circuit board.

[0005] In yet another construction, the invention provides a method of cooling a fully enclosed motor. The method includes enclosing a rotor and a stator within a housing such that the stator cooperates with the housing to define an axial space. Electrical power is provided to the rotor and the stator to produce rotation of the rotor about a rotational axis. A circuit board is positioned within the axial space. The circuit board is spaced apart from the rotor, the stator, and the housing. A fan is positioned axially between the stator and the circuit board. The fanand the rotor are coupled for rotation such that during rotor rotation, the fan draws air axially from the axial space and discharges air radially between the stator and the circuit board.

[0006] Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Fig. 1 is a perspective view of a motor;

[0008] Fig. 2 is a section view of the motor of Fig. 1 ;

[0009] Fig. 3 is a perspective view of a stator for use with the motor of Fig. 2;

[0010] Fig.4 is a perspective view of a printed circuit board of the motor of Fig. 2;

[0011] Fig. 5is a perspective view of the printed circuit board of Fig. 4 coupled to the stator of Fig. 3;

[0012] Fig. 6 is a perspective view of a fan of the motor of Fig. 2;

[0013] Fig. 7 is a perspective view of a Hall sensor support of the motor of Fig. 2;

[0014] Fig. 8 is a perspective view of the Hallsensor support of Fig. 7 coupled to the printed circuit board of Fig. 4; [0015] Fig. 9 is a perspective view of the Hallsensor support of Fig. 8 in communication with a Hallsensor and a Hallsensor house.

[0016] Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The use of "including," "comprising," or "having" and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless specified or limited otherwise, the terms "mounted," "connected," "supported," and "coupled" and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Further, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings.

DETAILED DESCRIPTION

[0017] The term "enclosing" as used herein means enclosed to the extent that little or no air can flow into or out of the housing. The only opening is typically the rotor shaft opening and very little air can move into or out of the housing. Thus, an enclosed housing does not allow for enough air flow to provide the desired level of cooling.

[0018] Fig. 1 illustrates a fully enclosed motor 10 embodying the invention. The motor 10 is a variable speed electric motor that is powered through an electric connection 12. The motor includes a housing 14 having a first end portion 18 and a second end portion 22 that partially contain a rotor26 (Fig. 2). Each of the first end portion 18 and the second end portion 22 are cup-shaped with a flange 30 extending around an open end 34. The flanges 30 of the first end portion 18 and the second end portion 22 sealingly engage one another to fully enclose and substantially seal an inner space 36 (Fig. 2). In the illustrated construction of Fig. 1, each flange 30 includes four ears 38 equally spaced from one another around a perimeter 42 and arranged to receive a fastener 46 (Fig. 2) to facilitate the assembly of the housing 14. In preferred constructions, a seal 50 is positioned between the flanges 30 to further enhance the seal between the flanges 30. In the illustrated construction a resilient gasket type seal is employed with other constructions using different seal types or additional seals in conjunction with the gasket type seal.

[0019] Fig. 2 is a cross section of the motor 10 of Fig. 1 better illustrating the internal components and arrangement of the motor 10. As can be seen, the illustrated construction includes a stator 54, the rotor 26, a fan 58, a printed circuit board (PCB) 62, a first bearing 66, and a second bearing 70. The rotor 26 is a substantially conventional rotor including a shaft 74 having a first end 78 disposed fully within the housing 14 and a second end 82 extending out of the housing 14. The shaft 74 extends along a longitudinal or rotational axis 86. Permanent magnets (not shown)are coupled to the shaft 74 and are arranged to interact with the stator 54 to produce rotation and torque in response to the application of electrical power to the motor 10. Of course, other types of rotors could be employed with the invention described herein.

[0020] As shown in Fig. 2, apair of bearing seats94 extend axially inwardly from thehousing 14 into the inner space 36. The first and second bearings 66, 70 are each recessed in one of the bearing seats94 of the housing 14 and fully support the rotor 26 for rotation.

[0021] Referring to Fig. 3, the substantially cylindrical stator 54 is disposed within the housing 14 and is operable to produce a magnetic field. The stator 54 includes a first end 98 and a second end 102. An opening 106 extends along the rotational axis 86 between the first end 98 and the second end 102 and is configured to receive the rotor 26. The stator 54 includes four slots 110 defined between teeth 114Magneticcoilsl 18 wind around the teeth 1 Hand are disposed in the slots 110 and cooperate to define windings 122. Alternatively, the stator 54 may include more or fewer slots to define different pole orders (e.g., 4 pole, 6 pole, 8 pole, etc.)

[0022] As illustrated in Fig. 3, a first ring 126 is coupled to the first end 98 of the stator 54, and a second ring 130 is coupled to the second end 102 of the stator 54. The rings 126, 130 are preferably made of plastic, but may be made of an alternate material. The rings 126, 130 include four slots 134 that correspond with the slots 110 of the stator 54. A plurality of flanges 138 extend axially from the rings 126, 130 and include a shoulder portion 142. An interlocking member 146 is coupled to each of two of the shoulder portions 142. Eight slot portions 148extend axially from each ring 126, 130. A connector 150 is configured to be received by each slot portion 146 to connect to the windings 122.

[0023] As shown in Fig. 6, the fan 58 is fixedly coupled to the shaft 74 adjacent the rotor 26 so that the fan 58 rotates with the shaft 74 and provides cooling air to the motor 10. In other motors, other types of fans or other fan arrangements may be employed. The fan 58 is substantially circular and includes a central aperture 152. Preferably, the fan 58 is constructed as a radial flow fan. The fan 58 includes an inlet 154 arranged axially along the shaft 74 and an outlet 158at a periphery 160 of the fan 58. Fan blades 162 extend axially from the fan 58.

[0024] Referring to Fig. 4, the PCB 62 is a substantially annular circuit board having a central aperture 166. The central aperture 166 is sized to provide clearance between the PCB 62 and the shaft 74. The fan inlet 154 is sized to closely match the size of the central aperture 166. A plurality of circular cooling apertures 170 are defined in the PCB62 to allow air to pass through the PCB 62. Alternatively, more or fewer cool apertures 170 may be included in the PCB for cooling purposes. Additionally, the cooling apertures 170 may be formed in an alternate shape such as a square, a triangle, etc. A plurality of relief notches 174 extend into aperimeter 178 of the PCB 62. In alternate embodiments, a non-circular perimeter 178 may be employed to increase the surface area of the PCB for cooling purposes. Two rectangular slots 182 are provided in the PCB 62 on either side of the central aperture 166. Three rectangular apertures 186 are provided at one end of the board 62. Three circular sensor apertures 188 are provided in the PCB 62 adjacent the rectangular apertures 186.

[0025] Referring to Figs. 7-9, a sensor supportl90 is coupled to the PCB 62. The sensor supportl90 includes interlocking members 194 for securing the support 190 to the PCB 62. Three circular apertures 195extend through a portion of the support 190. As shown in Fig. 9, a sensor house 198 is coupled between the PCB 62 and align with the circular apertures 195. The sensor house 198 includes three apertures 196 extending through the house 198. A sensor 202, such as a Hall Effect Sensoris coupled to the support 190andincludes a body 206with three prongs210 extending from the body 206. The prongs 210 or leads pass through the apertures 195 of the support 190 and through the apertures 196 of the house 198 before connecting with the PCB 62. [0026] To assemble the motor 10 of Figs. 1-9, the shaft 74 and the rotor 26 are fixedly coupled to one another for co-rotation. The rotor 26 is positioned adjacent the stator 54 such that the rotor 26 is partially within the stator 54. The fan 58 is positioned along the shaft 74 adjacent the stator 54 as shown in Figs. 2 and 6. Many options are available to connect the rotor 26 and the fan 58 to the shaft 74 including shrink fits, keys and slots, splines, welding, brazing, soldering, adhesives, etc. The first ring 126 and the second ring 130 are coupled to the first end 98 and the second end 102 of the stator 54, respectively. The PCB 62 is coupled to the first ring 126 such that the two rectangular slots 182 receive the interlocking members 194 to prevent the PCB 62 from rotating with respect to the stator 54. Referring to Figs. 2 and 5, the PCB 62 is spaced apart from the windings 122 to define a first axial gap 214 therebetween. The PCB 62 is also spaced apart from the housing 14 to define a second radial gap 222. The fan 58 is disposed within the first axial gap 214. The windings 122 are wound through the slots 110 in the stator 54 and around the first and second rings 126, 130 such that one end of the windings 122 terminate within the rings 126, 130. Referring to Fig. 9, the connector 150 is pressed into one of the slot portions 148on the ring 126 such that is it in contact with the periphery 178 of the PCB 62 (Fig. 5). Solder is applied between the connector 150 and the PCB 62 to make an electrical connection between the windings 122 and the PCB 62. As shown in Fig. 8, the interlocking members 194 of the sensor support 190 are receiving in the three apertures 186 in the PCB 62 to couple the support 190 to the PCB 62. The three prongs 210 of the sensor 202 are positioned through the apertures in the support 190, through the apertures 196 in the house 198, and through the apertures 188 in the PCB 62.

[0027] In operation, the rotor 26 and the stator 54 cooperate as is well known in the art to produce rotation of the shaft 74. The first bearing 66 and the second bearing 70 support the shaft 74, the fan 58, and the rotor 26 for the desired rotation. Electrical current flows through the windings 122 and produces heat. As shown in Fig. 2, the fan 58 directs air flow through the windings 122, through the second radial gap 222, and through the central aperture 166 of the PCB 62 to define a circular air distribution stream 218 around the PCB 62. The air circulation aids in cooling the PCB 62 components. The relief notches 174 in the perimeter 178 of the PCB 62 provide additional air flow. [0028] In addition to the cooling advantages provided by the illustrated design, other advantages and improvements are achieved. For example, the second air gap 222 provides increased electrical isolation between the high voltage components supported by the PCB 62 and the motor housing 14. In prior designs, the PCB 62 may be connected to the outer shell of the motor to provide the necessary cooling. Such a connection required the use of exotic materials that conduct heat efficiently but that do not conduct electricity. Maintaining the electric isolation as illustrated herein simplifies the assembly and components of the motor and reduces material costs.

[0029] Various features and advantages of the invention are set forth in the following claims.

Claims

1. A motor comprising:

a stator including a plurality of end coils;

a control coupled to a circuit board, the circuit board coupled to the stator and spaced apart from the end coils to define a first radial gap;

a rotor positioned adjacent the stator and supported for rotation with respect to the stator; a fan coupled to the rotor; and

a housing surrounding and fully enclosing the stator and the circuit board, the housing spaced apart from the circuit board to define a first axial gap and a second radial gap, wherein the fan directs a flow of cooling air through the first radial gapand the second radial gap to cool the circuit board.

2. The motor of claim 1, wherein the fan is disposed within the first radial gap axially between the end coils and the circuit board.

3. The motor of claim 1, wherein the fan includes an inlet arranged axially along the rotor shaft and a radial outlet at an outer periphery of the fan.

4. The motor of claim 1 , wherein the circuit board includes a central aperture sized to cooperate with the rotor to define an annular flow space.

5. The motor of claim 1, further comprising a plurality of standoffs coupled to the stator, each standoff extending axially into the first axial gap and including a shoulder positioned to support the circuit board.

6. The motor of claim 5, wherein a portion of the plurality of standoffs include an interlocking member arranged to engage the circuit board to inhibit unwanted axial movement of the circuit board with respect to the stator.

7. The motor of claim 1, further comprising Hall Sensor support removable coupled to the circuit board.

8. The motor of claim 1, wherein the circuit board defines a plurality of cooling apertures that extend through the circuit board, and wherein a portion of the cooling air passes through each of the plurality of apertures.

9. The motor of claim 1 , wherein the fan includes an axial inlet having a first diameter and the circuit board is annular and includes a central aperture having a second diameter, and wherein the first diameter and the second diameter are substantially the same.

10. A motor comprising :

a stator including a first end having first end coils, a second end having second end coils, and an opening extending along a rotational axis between the first end and the second end;

a housing surrounding and completely enclosing the stator and including a first end and a second end, the first end of the housing cooperating with the first end of the stator to define an axial space;

a first support coupled to the first end of the housing;

a second support coupled to the second end of the housing;

a rotor positioned at least partially within the opening and supported for rotation by the first support and the second support;

a circuit board coupled to the first end of the stator and positioned within the axial space; and

a fan coupled to the rotor and disposed axially between the first end coils and the circuit board, the fan rotating in response to rotor rotation and operable to draw air into an axial inlet and to discharge air radially to produce a continuous flow of cooling air around the circuit board.

11. The motor of claim 10, wherein the fan includes radial outlet at an outer periphery of the fan.

12. The motor of claim 10, wherein the circuit board includes a central aperture sized to cooperate with the rotor to define an annular flow space.

13. The motor of claim 10, further comprising a plurality of standoffs coupled to the stator, each standoff extending axially into the first axial gap and including a shoulder positioned to support the circuit board.

14. The motor of claim 13, wherein a portion of the plurality of standoffs includes an interlocking member arranged to engage the circuit board to inhibit unwanted axial movement of the circuit board with respect to the stator.

15. The motor of claim 10, further comprising Hall Sensor support removable coupled to the circuit board.

16. The motor of claim 10, wherein the circuit board defines a plurality of cooling apertures that extend through the circuit board, and wherein a portion of the cooling air passes through each of the plurality of apertures.

17. The motor of claim 1 , wherein the axial inlet has a first diameter and the circuit board is annular and includes a central aperture having a second diameter, and wherein the first diameter and the second diameter are substantially equal.

18. A method of cooling a fully enclosed motor, the method comprising:

enclosing a rotor and a stator within a housing, the stator cooperating with the housing to define an axial space;

providing electrical power to a rotor and a stator to produce rotation of the rotor about a rotational axis;

positioning a circuit board within the axial space, the circuit board spaced apart from the rotor, the stator, and the housing;

positioning a fan axially between the stator and the circuit board; and

coupling the fan and the rotor for rotation such that during rotor rotation, the fan draws air axially from the axial space and discharges air radially between the stator and the circuit board.

19. The method of claim 18, further comprising establishing a continuous flow of cooling air from a radial fan outlet, around the circuit board and into a fan axial inlet.

20. The method of claim 19, further comprising directing a portion of the flow of cooling air through a plurality of apertures formed through the circuit board.