Source: http://www.google.com/patents/US6798091?dq=7,117,286
Timestamp: 2017-03-29 18:32:53
Document Index: 22426521

Matched Legal Cases: ['art 31', 'art 31', 'art 31', 'art 31', 'art 31', 'art 31', 'art 31', 'art 31', 'art 31', 'art 31', 'art 31', 'art 31', 'art 31', 'art 31']

Patent US6798091 - Watertight brushless fan motor - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsIn a watertight brushless fan motor of the present invention, a first pad 33 is disposed in a first space between a stator 1 and a circuit substrate 3, A second pad 35 is disposed in a second space between the circuit substrate 3 and a plate-like section 7 c of a case 7. Spaces between the plate-like...http://www.google.com/patents/US6798091?utm_source=gb-gplus-sharePatent US6798091 - Watertight brushless fan motorAdvanced Patent SearchTry the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents.Publication numberUS6798091 B2Publication typeGrantApplication numberUS 10/306,933Publication dateSep 28, 2004Filing dateNov 29, 2002Priority dateNov 29, 2001Fee statusLapsedAlso published asUS7117580, US20030173851, US20040205956Publication number10306933, 306933, US 6798091 B2, US 6798091B2, US-B2-6798091, US6798091 B2, US6798091B2InventorsNaruhiko Kudou, Hisashi Takizawa, Osamu KawakamiOriginal AssigneeSanyo Denki Co., Ltd.Export CitationBiBTeX, EndNote, RefManPatent Citations (6), Referenced by (13), Classifications (15), Legal Events (6) External Links: USPTO, USPTO Assignment, EspacenetWatertight brushless fan motor
US 6798091 B2Abstract
In a watertight brushless fan motor of the present invention, a first pad 33 is disposed in a first space between a stator 1 and a circuit substrate 3, A second pad 35 is disposed in a second space between the circuit substrate 3 and a plate-like section 7 c of a case 7. Spaces between the plate-like section 7 c of the case 7 and a bearing supporting cylindrical section 7 a are formed with an insulating resin in such a manner that the stator 1 and the circuit substrate 3 are included inside, thereby forming a molded part 31, With this arrangement, the watertight brushless fan motor is provided that can prevent occurrence of a crack in the outer surface of the molded part due to the so-called molding shrinkage of the insulating resin or expansion and shrinkage of the insulating resin caused by a change in ambient temperature.
What is claimed is: 1. A watertight brushless fan motor comprising:
a stator provided with a plurality of stator magnetic poles, each of which has a winding wound around each of a plurality of projecting pole portions of an iron core constituted by a plurality of laminated steel plates; a circuit substrate mounted with electronic components constituting a control circuit for controlling a current flow through the winding, the circuit substrate being fixed to the stator, spaced from the projecting pole portions at a predetermined distance; a rotor including a plurality of rotor magnetic poles, each of which is made of a permanent magnet, on an inner peripheral side thereof and including a plurality of blades on an outer peripheral side thereof; a case including a bearing supporting cylindrical section in which a bearing for rotatably supporting a rotary shaft of the rotor is received, a cylindrical housing section for surrounding an outer periphery of the blades of the rotor, a plate-like section extending from an end of the bearing supporting cylindrical section in a direction perpendicular to a center line of the bearing supporting cylindrical section, spaced from the circuit substrate at a predetermined distance, and a plurality of webs for connecting the plate-like section to the housing section; one or more pads disposed in at least one of a first space between the stator and the circuit substrate and a second space between the circuit substrate and the plate-like section of the case, and made or an electrical insulating material, for occupying a main portion of one of these spaces or both; and a molded part made of an insulating resin in such a manner that the stator, the circuit substrate, and the one or more pads are included therein. 2. The watertight brushless fan motor as claimed in claim 1, wherein one or more pads are disposed in the an outer surface of the molded part due to expansion and shrinkage of the insulating resin.
3. The watertight brushless fan motor as claimed in claim 1, wherein the molded part comprises a first molded part including the stator and a second molded part having such a shape and dimension that includes the circuit substrate and form a step portion for the first molded part, and
wherein the shape and the dimension of the one or more pads disposed in the first space are defined to suppress occurrence of a crack at a boundary between the first molded part and the second molded part due to expansion and shrinkage of the insulating resin. 4. The watertight brushless fan motor as claimed in claim 1, wherein the one or more pads disposed in the first space comprise a single first pad, and
wherein the first pad comprises a cylindrical section fitted into the bearing supporting cylindrical section and a plate-like section extending radially outward from the cylindrical section, and the plate-like section is formed with a plurality of slits into which part of windings of the stator magnet poles are inserted. 5. The watertight brushless fan motor as claimed in claim 4, wherein one or more curved surface extended sections, extending both in a circumferential direction of the bearing supporting cylindrical section and in a center line direction of the hearing supporting cylindrical section and having curved surfaces respectively curved along magnetic pole face of the projecting pole portions, are integrally formed at an end of the plate-like section located radially outward.
6. The watertight brushless fan motor as claimed in claim 5, wherein a length of the curved surface extended sections in the center line direction is corresponding to a portion of the first molded part facing the rotor, positioned on a side of the circuit substrate rather than on a side of the iron core.
7. The watertight brushless fan motor as claimed in claim 1, wherein the one or more pads disposed in the second space comprise a single second pad, and
wherein the second pad comprises a cylindrical section fitted into the bearing supporting cylindrical section and a plate-like section extending radially outward. 8. The watertight brushless fan motor as claimed in claim 7, wherein a part of the electronic components are mounted at a back of the circuit substrate facing the plate-like section of the case, and
wherein the plate-like section of the second pad is formed with at least one through hole for letting an electronic component large in size and dimension among the part of the electronic components pass therethrough. 9. The watertight brushless fan motor as claimed in claim 1, wherein the insulating resin is composed of a urethane resin.
According to the present invention, a pad is disposed in at least one of the first space between the stator and the circuit substrate and the second space between the circuit substrate and the plate-like section of the case. Thus, the thickness of the molded part can be reduced. For this reason, a molding shrinkage at the time of curing of the insulating resin can be reduced. Further, an unbalance of the thickness of portions of the molded part made of the insulating resin can be reduced. Hence, the amount of expansion and shrinkage of the insulating resin due to a change in ambient temperature can be reduced, thereby allowing prevention of occurrence of a crack in the outer surface of the molded part
The circuit substrate 3 is fixed to the stator 1. A plurality of electronic components 13 constituting a control circuit for controlling a current flow through the winding 11 are mounted at the back of the circuit substrate 3. The winding 11 constitutes part of the stator magnetic poles of the stator 1 The circuit substrate 3 faces a flat portion 7 c of the case 7, which will be described below. The lead wire of the winding 11 is electrically connected to the control circuit on the circuit substrate 3. The lead wire of the winding 11 passes through the through hole of the circuit substrate 3 and is wound around and soldered to a terminal pin 15 which is furthermore soldered to the electrode on the circuit substrate 3.
The case 7 includes a bearing supporting cylindrical section 7 a, a housing section 7 b, a plate-like section 7 c, an outside cylindrical section 7 d, and a plurality of webs 7 e. In the bearing supporting cylindrical section 7 a, two bearings 27 and 29 for rotatably supporting the rotary shaft 23 of the rotor 5 are received. The housing section 7 b is of a cylindrical shape and surrounds the outer peripheral portion of the blades 21 of the rotor 5. The plate-like section 7 c is coupled to the bearing supporting cylindrical section 7 a, The outside cylindrical section 7 d extends from the outer end of the plate-like section 7 c in the direction of the center line of the bearing supporting cylindrical section 7 a, along the bearing supporting cylindrical section 7 a. The webs 7 e couples the plate-like section 7 c and the outside cylindrical section 7 d to the housing section 7 b. These components are integrally formed with a resin. The plate-like section 7 c extends from the end of the bearing supporting cylindrical section 7 a in the direction perpendicular to the center line of the bearing supporting cylindrical section 7 a, with a predetermined space formed between the plate-like section 7 c and the circuit substrate 3. The webs 7 e are arranged at intervals in the circumferential direction. On one of the webs 7 e is formed a lead wire receiving groove for receiving a plurality of lead wires connected to the control circuit of the circuit substrate 3 and for guiding them to the side of the housing section 7 b. On the bearing supporting cylindrical section 7 a of the case 7, a molded part 31, which is transparent in FIG. 1 and the outline of which is indicated by a dashed line, is formed of an insulating resin made of an urethane resin in such a manner that the stator 1 and the circuit substrate 3 are included inside. The molded part 31 is constituted by a first molded part 31 a including the stator 1 and a second molded part 31 b including the circuit substrate 3. The second molded part 31 b has such a shape and dimension as to form a step section 31 c between the first molded part 31 a and the second molded part 31 b. On a portion adjacent to the step section 31 c with a predetermined gap, the ends of the rotor side case 17 and the rotor magnetic poles 19 of the rotor 5 are disposed. In a first space between the stator 1 included in the first molded part 31 a and the circuit substrate 3, a first pad 33 for occupying the main portion of the first space is disposed, while in a second space between the circuit substrate 3 included in the second molded part 31 b and the plate-like section 7 c of the case 7, a second pad 35 for occupying the main portion of the second space is disposed. The first pad 33 and the second pad 35 are both formed of an electrical insulating material made of a PBT resin, and their shapes and dimensions are defined so that it is possible to suppress occurrence of a crack on the outer surface of the molded part 31 due to expansion and shrinkage of the insulating resin at the time of molding.
As illustrated in FIGS. 2A to 2C, the first pad 33 includes a cylindrical section 33 a and a plate-like section 33 b, The cylindrical section 33 a is fitted into the bearing supporting cylindrical section 7 a of the case 7 through an insulator 2 (FIG. 1). The plate-like section 33 b extends radially outward from a position substantially in the middle of the center line of the cylindrical section 33 a. The plate-like section 33 b is formed with a plurality of slits 33 c, into which part of a plurality of the windings 11 wound around the projecting pole portions 9 a are respectively inserted. At the end of the plate-like section 33 b located radially outward, a plurality of curved surface extended sections 33 d are integrally formed. The curved surface extended sections 33 d extend both in the circumferential direction of the bearing supporting cylindrical section 7 a and in the center line direction of the bearing supporting cylindrical section 7 a and have curved surfaces respectively curved along the pole faces 9 b of the projecting pole portions 9 a. In a plurality of the curved surface extended portions 33 d, cutout portions 33 c are respectively formed over a half of the end of the plate-like sections 33 b in the circumferential direction so that the insulating resin can easily flow into regions respectively surrounded by the curved surface extended sections 33 d, the plate-like section 33 b, and the cylindrical section 33 a at the time of molding. The length (width dimension) of the curved surface extended sections 33 d in the center line direction thereof is set to the one substantially corresponding to the portion of the first molded part 31 a facing the rotor 5, positioned on the side of the circuit substrate 3 rather than on the side of the iron core 9. With this arrangement, the insulating resin is thinly molded on the curved surface extended sections 33 d, thereby allowing effective prevention of a crack that will occur at a boundary B between the first molded part 31 a and the second molded part 31 b due to expansion or shrinkage of the insulating resin.
As illustrated in FIGS. 3A and 3B, the second pad 35 Includes a cylindrical section 35 a and a plate-like section 35 b that have been integrally formed. The cylindrical section 35 a is fitted into the bearing supporting cylindrical section 7 a of the case 7. The plate-like section 35 b extends radially outward from one end of the cylindrical section 35 a. The second pad 35 is disposed so that the other end of the cylindrical section 35 a faces the circuit substrate 3 to form a gap between the plate-like section 35 b and the circuit substrate 3. The outline of the plate-like section 35 b is nearly a circle partially having a straight line 35 c. Three through holes 35 d for passing electronic components large in size and dimension, mounted on the circuit substrate 3, are formed in the plate-like section 35 b. Further, at the edges of the plate-like section 35 b on the side opposite to the circuit substrate 3 are formed curved portion 35 e. Next, a method of resin molding used in the embodiment of the present invention will be described. First, the stator 1, the circuit substrate 3, and the first pad 33 are combined to construct a stator assembly. Then, a die 41, an annular member 43, and a fixing jig 45 as illustrated in FIG. 5 are prepared. As illustrated in FIG. 4, the die 41 includes a cylindrical body 41 a and a blockage wall 41 c having an engaging portion 41 b that can be engaged with the bearing supporting cylindrical section 7 a of the case 7. The blockage wall 41 c blocks one opening of the cylindrical body 41 a. An annular end surface 41 d of the cylindrical body 41 a has three screw holes (not shown) in the circumferential direction thereof at equal intervals. The annular member 43 is made of a resin and has three through holes formed in positions corresponding to the positions of the screw holes of the die 41. The annular member 43 is ready for mounting at the annular end surface 41 d of the die 41. As illustrated in FIG. 5, the annular member 43 has such a shape and dimension as to align a center line L1 of the cylindrical body 41 a of the die 41 over a center line L2 of the bearing supporting cylindrical section 7 a when the die 41 is fixed to the case 7. In this case, as illustrated in FIG. 5, an inner peripheral end surface 43 a of the annular member 43 is brought into contact with an outer peripheral surface 7 f of the outside cylindrical section 7 d of the case 7, thereby allowing this arrangement. The fixing jig 45 can fix the die 41 and the annular member 43 to the case 7, and has three through holes corresponding to the three screw holes of the die 41.
Next, the insulating resin made of the urethane resin is poured into the die 41 under low vacuum, thereby molding spaces between the plate-like section 7 c and the bearing supporting cylindrical section 7 a with the insulating resin in such a manner that the stator 1 and the circuit substrate 3 are included inside. Thus, the resin molding is completed. By performing molding with the resin according to this embodiment, the die 41 and the outside cylindrical section 7 d of the case 7 can be sealed by the annular member 43 made of the resin. In addition, the insulating resin can be molded with the center line L1 of the cylindrical body 41 a of the die 41 being aligned over the center line L2 of the bearing supporting cylindrical section 7 a. For this reason, it is possible to prevent contact of the insulating resin with the rotor 5 caused by misalignment between the center line of the cylindrical body 41 a of the die 41 and the center line of the bearing supporting cylindrical section 7 a. Further, the present invention is not limited to this embodiment, but various variations and modifications may be made without departing from the scope of the present invention.
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