JP4816479B2 - motor - Google Patents

Description

  The present invention includes a sliding bearing formed between an outer peripheral surface of a shaft and an inner peripheral surface of the sleeve by inserting a rotating shaft into the sleeve, and the lower end portion of the shaft supported rotatably is magnetically The present invention relates to a motor having a bearing structure for suction.

  Currently, some electronic devices are equipped with a disk drive motor that rotationally drives a blower fan, a recording disk, or the like. Some of these motors use a sliding bearing, and a motor equipped with the sliding bearing is supported by a shaft inserted into a sleeve so as to be rotatable around the rotation axis of the motor. The lower end of the shaft is slidably supported by a thrust plate provided at the bottom of the sleeve. There is also a non-contact support that magnetically supports the shaft in the axial direction.

  In such a bearing structure, since the rotor portion including the shaft can move in the axial direction with respect to the sleeve, the rotation of the rotor portion becomes unstable, resulting in noise and sliding loss. Will occur. For this reason, a motor employing a sliding bearing has a structure in which the rotor portion is restricted from moving in the axial direction of the rotating shaft.

  As one of the structures that regulate the movement of the rotor part, a magnet is provided on the back surface of the thrust plate (the surface opposite to the sliding surface of the thrust plate), and the shaft made of magnetic material is magnetically attracted to the thrust plate side. Such a structure is known (for example, Patent Document 1).

  Further, as a magnetic attraction structure similar to that of Patent Document 1, there is also known a structure in which a magnetic attraction force is increased by providing a cup-shaped back yoke made of a magnetic material on the attraction magnet (for example, Patent Document 2). The structure in which the back yoke is used in combination with this attraction magnet is an effective structure in that a predetermined magnetic attraction force can be obtained even with an inexpensive magnet and leakage flux of the magnet can be prevented.

JP-A-9-317755 JP 2000-245101 A

  By the way, the magnetic attraction structure of Patent Document 2 is configured such that the magnetic attraction force can be adjusted by detachably fitting and fixing the back yoke to the bearing holder. Therefore, when an excessive impact is applied from the shaft toward the lower side in the axial direction, the back yoke may be detached from the bearing holder. Therefore, the application of this motor is limited to the use environment in which the impact is not transmitted from the outside, or an impact resistant structure is required so that the impact is not applied to the back yoke in the motor or the electronic device equipped with the motor. Thus, the magnetic attraction structure using the back yoke has not been widely used due to circumstances such as a complicated structure.

  Therefore, an object of the present invention is to provide a motor having a magnetic attraction structure using a back yoke as a suction magnet for magnetically attracting the lower end portion of a shaft rotatably supported by a sleeve constituting a slide bearing in the axial direction. It is to provide a configuration capable of firmly fixing the back yoke.

  In order to solve the above-described problems, the motor of the present invention has a structure in which the shaft is magnetically attracted in the axial direction by a suction magnet disposed on the lower end side of the shaft that constitutes the sliding bearing with the sleeve. The suction magnet is housed in a cup-shaped magnet holder as a back yoke. The magnet holder is axially positioned at a predetermined portion inside the bearing holding portion, and is fixed by being sandwiched between a sleeve located on one side in the axial direction and a predetermined portion of the bearing holding portion located on the other side in the axial direction. ing.

  More specifically, the invention described in claim 1 is a motor, which has a shaft and a rotation drive magnet, and rotates around a rotation axis, and the rotation drive magnet and the radial direction or the A bearing is formed between a stator that is disposed at a position opposite to the axial direction of the rotating shaft and that has a coil that rotates and drives the rotor portion, and an insertion hole through which the shaft is inserted, and an outer peripheral surface of the shaft A cylindrical sleeve that rotatably supports the rotor portion with respect to the stator, a bottomed cylindrical cylindrical portion that holds the stator on the outer peripheral side surface, and holds the sleeve on the inner peripheral side surface; A bearing holding portion having a concave portion opened toward the sleeve side at the bottom of the cylindrical portion, and an end surface on the insertion direction side of the shaft, the end surface being magnetized in the insertion direction side And a cup-shaped bearing holder that is formed of a magnetic material and that accommodates the suction magnet so as to surround the opposite surface of the suction magnet facing the shaft and the radially outer peripheral surface. A magnet holder positioned in the axial direction in the concave portion of the portion, wherein the magnet holder is fixed by being sandwiched between the sleeve and the concave portion.

  The invention according to claim 2 is a motor, which has a shaft and a rotary drive magnet, and rotates around a rotary shaft, and the rotary drive magnet and the radial direction or the axial direction of the rotary shaft And a stator having a coil for rotating the rotor portion and a through hole through which the shaft is inserted, and forming a bearing between the outer peripheral surface of the shaft, A cylindrical sleeve that rotatably supports the rotor with respect to the stator, a cylindrical cylinder with a bottom that holds the stator on the outer peripheral side, and holds the sleeve on the inner peripheral side; A bearing holding portion having an inward protruding portion that protrudes inward in the radial direction on the inner peripheral side surface of the bottom portion and an end surface on the insertion direction side of the shaft are arranged to face the shaft and the insertion direction side. A suction magnet that sucks air; a cup portion that is formed of a magnetic material and that houses the suction magnet so as to surround the opposite surface of the suction magnet facing the shaft and the radially outer peripheral surface; An outer projecting portion projecting radially outward on the outer peripheral side surface of the cup portion, and a magnet holder in which the outer projecting portion is axially positioned on the inward projecting portion of the bearing holding portion; The magnet holder is fixed by being clamped by the sleeve and the inward protruding portion.

  A third aspect of the present invention is the motor according to the first or second aspect, wherein the sleeve is in contact with the magnet holder.

  According to a fourth aspect of the present invention, in the motor according to the first or second aspect, an intermediate member is interposed between the magnet holder and the sleeve. A fifth aspect of the present invention is the motor according to the fourth aspect, wherein the intermediate member is a thrust plate that is disposed at an upper end portion of the attraction magnet and slidably supports the shaft. It is characterized by.

  A sixth aspect of the present invention is the motor according to the fourth aspect, wherein the intermediate member is a retaining member that prevents the shaft from being detached from the sleeve.

  The invention according to claim 7 is the motor according to any one of claims 4 to 6, wherein the upper end of the shaft is provided with a large-diameter portion larger in diameter than the hole diameter of the insertion hole of the sleeve. The upper end of the sleeve has an annular recess in which the upper open end of the insertion hole is located below the upper end surface of the sleeve and accommodates the lower end of the large diameter portion, and the lower end of the sleeve Is characterized in that it is formed in a flat shape so as to include a position having the same diameter as the outer diameter of the large diameter portion or a smaller diameter.

  The invention according to claim 8 is the motor according to any one of claims 1 to 7, wherein the sleeve is in contact with an opening end of the magnet holder.

  The invention according to claim 9 is the motor according to any one of claims 1 to 7, wherein the magnet holder has a stepped portion projecting inward from an opening end portion, and the sleeve is formed of the sleeve. It contacts the step portion of the magnet holder.

  A tenth aspect of the present invention is the motor according to any one of the first to ninth aspects, wherein the sleeve is formed of a porous material impregnated with a lubricating oil and impregnates the lubricating oil. A lubricating oil impregnated member made of a porous material is provided in close contact with the sleeve.

  The invention according to claim 11 is the motor according to any one of claims 1 to 10, wherein the sleeve is held by the bearing holding portion via a cylindrical bearing holding member, and the magnet holder is The bearing holding member is fixed to the outer peripheral side surface of the bearing holding member so as to close the lower end opening thereof.

  A twelfth aspect of the invention is the motor according to any one of the first to eleventh aspects, wherein the rotor portion is provided with an impeller that generates an air flow by rotation.

According to a thirteenth aspect of the present invention, the rotor unit has a shaft and a rotation drive magnet, and rotates at a position opposite to the rotation drive magnet in the radial direction or the axial direction of the rotation shaft. A stator having a coil arranged to rotate the rotor portion and an insertion hole through which the shaft is inserted, and forming a bearing between the outer peripheral surface of the shaft, and thereby the rotor portion is fixed to the stator A cylindrical sleeve that is rotatably supported with respect to the cylindrical portion, a cylindrical portion having a bottomed cylindrical shape that holds the stator on the outer peripheral side, and holds the sleeve on the inner peripheral side; A bearing holding portion having a concave portion that opens toward the surface, and a suction magnet that is disposed to face an end surface on the insertion direction side of the shaft and that magnetically attracts the end surface to the insertion direction side An axial direction in the concave portion of the bearing holding portion, which is formed of a magnetic material and accommodates the suction magnet so as to surround the opposite surface and the radially outer peripheral surface of the suction magnet facing the shaft A magnet holder positioned in the axial direction , wherein the magnet holder is disposed between the sleeve and the bottom of the cylindrical portion in the axial direction, and the sleeve and the cylindrical portion in the axial direction. wherein the bottom and overlap with Rukoto of.

The invention according to claim 14 is the motor according to claim 13, wherein the sleeve is formed of a porous material impregnated with a lubricating oil, and the porous material impregnated with the lubricating oil. The lubricating oil impregnated member formed by the above is provided in close contact with the sleeve.

The invention according to claim 15 is the motor according to claim 14, wherein a small-diameter portion having an outer diameter smaller than an inner peripheral surface of the bearing holding portion is provided on the side of the magnet holder on the axial direction of the sleeve. It is formed and the oil retaining material is arrange | positioned at the outer peripheral surface of the said small diameter part, It is characterized by the above-mentioned.

A sixteenth aspect of the present invention is the motor according to the fourteenth or fifteenth aspect of the present invention, in which an axially open end side of the bearing holding portion is interposed between an end surface on the open end side in the axial direction of the sleeve and a minute gap. A sleeve retaining member facing in the axial direction is attached.

The invention according to claim 17 is the motor according to claim 16, wherein the size of the minute gap between the sleeve retaining member and the end face on the open end side of the sleeve is 0.7 mm or less. It is characterized by.

According to an eighteenth aspect of the present invention, in the motor according to the fourteenth or fifteenth aspect, at the axially open end side of the bearing holding portion, the sleeve coming out of contact with the end surface of the sleeve in the axial direction on the open end side. A stop member is attached.

A nineteenth aspect of the present invention is the motor according to any one of the fourteenth to eighteenth aspects, wherein the stator includes a coil, an insulator, and a stator core, and the sleeve retaining member and the insulator include It is characterized by being formed continuously.

A twentieth aspect of the present invention is the motor according to any one of the fourteenth to nineteenth aspects, wherein a recess is formed on an end surface of the sleeve in the axial direction on the opening end side so as to surround the shaft. Features.

The invention according to claim 21 is the motor according to claim 20, wherein an annular member is attached to an outer peripheral side surface of the shaft so that a part thereof is located inside the recess. To do.

The invention according to claim 22 is the motor according to claim 21, wherein the outer diameter of the annular member is larger than the inner diameter of the inner peripheral surface of the sleeve retaining member, and the sleeve is removed in the axial direction. The annular member is disposed between the stopper member and the sleeve.

  In the present invention, a magnetic attraction force always acts between the attraction magnet and the magnet holder and between the attraction magnet and the shaft, and the attraction magnet, the magnet holder, and the shaft are mutually magnetic. Adsorbed and substantially integrated. For this reason, when a load acts on the shaft in a direction away from the suction magnet, the magnet holder also acts in the same direction (a direction away from the bearing holding portion). Since it is pinched by the part, it is firmly fixed.

  Although the embodiment of the motor according to the present invention is illustrated using the blower fan shown in FIGS. 1 to 7, the present invention is not limited to the blower fan.

(First embodiment)
FIG. 1 is a cross-sectional view showing the blower fan of the first embodiment. FIG. 2 is an enlarged cross-sectional view of a main part of FIG. In addition, the axial direction here means the direction where the rotating shaft prescribed | regulated as a rotation center line of a ventilation fan extends.

  The blower fan 1 includes an impeller 2 that is rotationally driven by an electric current supplied from the outside. The impeller 2 is provided with a plurality of blades 3 on the outer periphery of the cup portion that opens downward, a cylindrical rotor yoke 4 made of a magnetic material on the inner peripheral side surface of the cup portion, and a cylinder on the inner peripheral side surface of the rotor yoke 4 And a shaft 6 is provided at the center of the cup portion. The shaft 6 is made of a magnetic material such as iron, and is insert-molded into a synthetic resin impeller 2.

  The frame 7 has a horizontal portion that expands in a disk shape at a position facing the lower side in the axial direction of the impeller 2, and a bottomed cylindrical bearing holding portion 7 a is formed at the center of the horizontal portion. On the inner peripheral side surface of the cylindrical portion of the bearing holding portion 7a, a sleeve 8 is formed by impregnating a lubricating oil into a cylindrical porous metal obtained by baking magnetic powder and constituting a sliding bearing. It is press-fitted and fixed. The frame 7 is integrally formed of a synthetic resin with a wind tunnel portion (not shown) that surrounds the impeller 2 and forms an air flow path. The frame 7 may be formed from either metal or rigid resin.

  A stator 9 in which a coil is wound around a stator core formed by laminating a plurality of silicon steel plates via an insulator formed of a synthetic resin is fitted and fixed to the outer peripheral side surface of the cylindrical portion of the bearing holding portion 7a. . This coil is electrically connected to a circuit board 10 located below the stator 9 via a conduction pin 11. A lead wire (not shown) for connecting to an external power source is drawn out from the circuit board 10.

  In the sleeve 8, the shaft 6 is inserted into an insertion hole 8 a provided in the center, and the inner peripheral side surface of the insertion hole 8 a and the outer peripheral side surface of the shaft 6 constitute a sliding bearing. When the shaft 6 is inserted into the insertion hole 8a, the lubricating oil oozes out from the inner peripheral side surface of the insertion hole 8a to reduce the friction with the shaft 6, and the shaft 6 is supported rotatably with respect to the sleeve 8. The The large-diameter portion 2a formed around the shaft 6 has a structure for preventing the shaft 6 from coming off from the sleeve 8 so that a part of the insulator of the stator 9 is hooked in the axial direction inside the protruding portion 9a that protrudes toward the inner diameter side. Is configured.

  A circular recess 7c that opens upward is formed in the bottom 7b that closes the lower end opening of the cylindrical portion of the bearing holding portion 7a, and a cup-shaped magnet holder 14 is disposed in the recess 7c.

  The magnet holder 14 is formed in a cup shape by pressing a metal plate made of a magnetic material such as iron. The magnet holder 14 accommodates a suction magnet 13 which will be described later, a cup portion 14b surrounding the lower end portion of the suction magnet 13 and the outer peripheral side surface in the radial direction, and an opening end of the cup portion 14b radially outward. An eaves part (corresponding to an outward projecting part) 14a that expands is provided. The magnet holder 14 is positioned in the axial direction with the bottom surface of the cup portion 14b in contact with the bottom surface of the recess 7c, and is press-fitted and fixed in the recess 7c. By press-fitting and fixing the magnet holder 14 in the recess 7c, the magnet holder 14 can be stably held in the bearing holding portion 7a, and the magnet holder 14 can be stopped after the magnet holder 14 is assembled when the blower fan 1 is assembled. It can be in a state, and workability is good.

The magnet holder 14 is made of a circular suction magnet 13 for magnetically attracting the shaft 6 and a wear-resistant resin for slidingly supporting the lower end portion of the shaft 6 on the suction magnet 13. The formed thrust plate 12 is accommodated. Since the magnet holder 14 is in contact with at least the lower end surface of the suction magnet 13, the magnet holder 14 is firmly adsorbed by a magnetic force and acts as a back yoke that increases the magnetic force of the suction magnet 13. The thrust plate 12 has a circular shape smaller than the inner diameter of the magnet holder 14, and the same lubricating oil as that of the sleeve 8 is interposed between the suction magnet 13 and is in close contact with the surface tension acting between the two members. Since the stacking thickness when the suction magnet 13 and the thrust plate 12 are stacked is sufficiently smaller than the depth of the magnet holder 14, the thrust plate 12 does not deviate greatly in the lateral direction. Further, since the magnet holder 14 surrounds the lower end surface and the outer peripheral surface of the attracting magnet 13, it is possible to prevent leakage of magnetic flux from here toward the outside of the frame 7.

  The lower end portion of the shaft 6 inserted into the sleeve 8 is magnetically attracted to the lower side in the axial direction by the attracting magnet 13, and is always slid on the thrust plate 12 while an urging force on the lower side in the axial direction is applied by this magnetic force. Move. For this reason, it is possible to prevent noise caused by hitting noise that is caused by repeated contact and non-contact between the shaft 6 and the thrust plate 12, or a sliding loss in which the shaft 6 slides while being displaced laterally on the thrust plate 12. This magnetic force is set to a magnitude that prevents the impeller 2 including the shaft 6 from separating from the thrust plate 12 and becoming difficult to contact. For example, when the blower fan 1 is arranged upside down and rotated, the magnetic force is not only the weight of the impeller 2 but also the buoyancy that acts in the direction in which the impeller 2 moves away from the frame 7 by the rotation of the impeller 2. Are set to be larger than the combined load. Moreover, when not arrange | positioning the said ventilation fan 1 upside down, the grade which becomes larger than the buoyancy may be sufficient. Even if an excessive force more than the magnetic force acts on the impeller 2 toward the upper side in the axial direction, the shaft 6 does not come out of the sleeve 8 by the above-described retaining structure.

  The lower end surface of the sleeve 8 is in contact with the upper surface of the collar portion 14 a of the magnet holder 14. Thereby, the magnet holder 14 is clamped between the lower end surface of the sleeve 8 and the recessed part 7c of the bearing holding part 7a, and the movement in the axial direction is restricted. That is, the magnet holder 14 is not only fixed by the pressing force acting in the radial direction between the inner peripheral side surface in the concave portion 7c of the bearing holding portion 7a but also sandwiched by the sleeve 8 and the bottom portion 7b of the bearing holding portion 7a. Has been. Thereby, even if the radial pressing force acting to fix the magnet holder 14 is released for some reason, the magnet holder 14 is restricted in movement in the axial direction, so the fixed state is maintained, The occurrence of defects can be prevented. Therefore, the magnet holder 14 is firmly fixed to the bearing holding portion 7a. In addition, although it is preferable that the sleeve 8 presses the collar part 14a, the case where it abuts or does not press may be sufficient.

  As described above, a magnetic attraction force always acts between the attraction magnet 13 and the magnet holder 14 and between the attraction magnet 13 and the shaft 6. The holder 14 and the shaft 6 are structured to be substantially integrated by magnetically attracting each other. Therefore, when the magnet holder 14 is not sufficiently fixed and a force directed upward in the axial direction acts on the impeller 2, the thrust plate 12, the suction magnet 13 and the magnet holder 14 are integrated with the shaft 6, Although there is a possibility that the magnet holder 14 may come off from the bearing holding portion 7a, in this embodiment, since the magnet holder 14 is firmly fixed as described above, such a problem can be prevented.

  Further, the lower end portion of the sleeve 8 is formed with a thin portion 8b whose outer diameter is reduced compared to the upper end side. Therefore, an annular space 15 is formed between the outer peripheral side surface of the thin portion 8b of the sleeve 8 and the inner peripheral side surface of the bearing holding portion 7a facing this. The annular space 15 accommodates an annular felt (lubricant impregnated member) 16 in which the lubricating oil of the sleeve 8 is impregnated. The felt 16 is a ring slightly larger than the annular space 15 and is accommodated so as to be pressed against the outer peripheral side surface of the thin portion 8 b of the sleeve 8 facing the annular space 15. Therefore, the lubricating oil is supplied from the felt 16 to the sleeve 8. Since the porosity of the felt 16 is sufficiently larger than the porosity of the sleeve 8, the use of this felt 16 can retain more lubricating oil in the sleeve 8 and extend the life of the bearing. it can.

  By disposing the felt 16 on the bottom 7b side of the bearing holding portion 7a as described above, the felt 16 is confined on the back side of the sleeve 8 and the bearing holding portion 7a, thereby preventing the felt 16 from detaching and lubricating oil from leaking. can do. Further, by forming the annular space 15 from the lower end portion of the sleeve 8, the annular space 15 can be easily formed.

  Further, by bringing the sleeve 8 into contact with the flange portion 14c of the magnet holder 14 as described above, not only the magnet holder 14 but also the sleeve 8 can be positioned in the axial direction.

  The sleeve 8 is formed with a thin portion 8b in order to secure a space for placing the felt 16, and the lower end surface of the sleeve 8 is abutted against the flange portion 14c of the magnet holder 14 and positioned in the axial direction. If the flange 14c is not provided, positioning is performed on the bottom 7b side of the bearing holding portion 7a. However, when the thin-walled portion 8b abuts near the corner of the opening edge of the recess 7c, There is a possibility that the sleeve will be crushed, and in this configuration, the sleeve is difficult to position, but in this embodiment, there is no such inconvenience. That is, the axial positioning of the sleeve 8, the fixing of the magnet holder 14, and the securing of the annular space 15 for arranging the felt 16 can be realized at the same time.

  Most of the lubricating oil in the felt 16 is absorbed from the surface of the sleeve 8 into the internal gap by capillary action. Some of the lubricating oil is transmitted along the outer side of the cup part 14b of the magnet holder 14 and the inner peripheral side surface of the bearing holding part 7a. The bearing holding part 7a has a bottomed cylindrical shape integrated with the bottom part 7b. Therefore, the lubricant does not leak to the outside. Further, in order to prevent the lubricating oil from flowing outside the cup portion 14b of the magnet holder 14, the flange portion 14a of the magnet holder 14 may be extended radially outward to cover the felt 16. Further, when the blower fan 1 is inverted and used, the lubricating oil flows in a direction away from the bottom 7b of the bearing holding portion 7a by its own weight, so that most of the lubricating oil in the felt 16 is effectively used for the sleeve 8. be able to.

  In general, a blower fan has a larger buoyancy caused by the rotation of a rotor including the impeller than a normal motor (here, a motor without an impeller), and a rotational resistance caused by fluctuations in atmospheric pressure due to factors other than the blower fan. The rotor including the impeller is likely to become unstable because it is easily received. Therefore, when a sliding bearing is used for the blower fan, due to the structure of the bearing, the impeller rotates unstablely and the above-described noise and sliding loss are likely to occur. Therefore, when the present invention is used for a blower fan, the advantages of the present invention can be effectively utilized.

(Second Embodiment)
Next, the ventilation fan 1 of 2nd Embodiment is demonstrated with reference to FIG.3 and FIG.4. Since the basic configuration of the blower fan 1 shown in FIG. 3 is the same as that of the first embodiment, the description will focus on differences from the first embodiment.

  Since the sleeve 8 of the present embodiment does not use the felt 16 of the first embodiment, there is no thin portion 8b, and the outer peripheral side surface has a constant outer diameter from the upper end to the lower end. In addition, an annular recess 8c is formed around the insertion hole 8a at the upper end of the sleeve 8, and the opening end of the insertion hole 8a is located in the annular recess 8c. The inner peripheral side surface of the annular recess 8c forms an inclined surface whose inner diameter increases toward the upper side. The maximum inner diameter of the inner peripheral side surface is sufficiently larger than the maximum outer diameter of the large-diameter portion 2a that faces the upper side of the annular recess 8c and is formed around the shaft 6. The lower end portion of the large-diameter portion 2a is accommodated in the annular recess 8c (that is, the lower end surface of the large-diameter portion 2a is positioned below the upper end surface of the sleeve 8).

  On the other hand, an annular recess 8d whose inner peripheral wall is inclined is formed around the insertion hole 8a at the lower end of the sleeve 8, and the opening end of the insertion hole 8a is located in the annular recess 8d. The inner diameter is sufficiently smaller than the maximum outer diameter of the large diameter portion 2a. Therefore, the area of the lower end surface of the sleeve 8 is wider than the area of the upper end surface. That is, the sleeve 8 has an asymmetric shape with different shapes at both ends.

  The thrust plate (corresponding to the intermediate member) 12 has an arc portion having an outer diameter substantially the same as the inner diameter of the bearing holding portion 7a and an arc shape so that at least the magnet holder 14 is hidden, as shown by the mesh pattern in FIG. It is a D-shape consisting of a straight line section connecting the end portions of the section with straight lines. The thrust plate 12 is sandwiched between the sleeve 8 and the concave portion 7c of the bearing holding portion 7a together with the magnet holder 14. The flange portion 14a of the magnet holder 14 is press-fitted and fixed in the concave portion 7c of the bottom portion 7b so as to be flush with the surface of the bottom portion 7b. The suction magnet 13 is also thick enough to be flush with the flange 14a. Therefore, the thrust plate 12 and the magnet holder 14 are sandwiched between the sleeve 8 and the concave portion 7c of the bearing holding portion 7a. Since the thrust plate 12 is sandwiched between these two members, the thrust plate 12 can be fixed more securely than in the case of fixing by the surface tension of the lubricating oil as in the first embodiment.

  The magnet holder 14 is not only fixed by a pressing force acting in the radial direction between the inner peripheral side surface in the concave portion 7c of the bearing holding portion 7a but also sandwiched between the sleeve 8 and the concave portion 7c of the bearing holding portion 7a. Thus, the bearing holding portion 7a is firmly fixed.

  When the thrust plate 12 is inserted into the bearing holding portion 7 a, a closed space is formed on the bottom side of the bearing holding portion 7. This closed space is increased in pressure as the thrust plate 12 approaches the bottom 7b of the bearing holding portion 7a, making it difficult to insert the thrust plate 12. However, since the thrust plate 12 is D-shaped, the bearing holding portion 7a Thus, the thrust plate 12 can be inserted smoothly. After the insertion is completed, the thrust plate 12 can be disposed so as to cover the magnet holder 14 and be sandwiched between the sleeve 8 and the bottom portion 7b regardless of the position in the circumferential direction.

  On the lower end surface of the sleeve 8, four radially extending lateral grooves 8e provided at equal intervals in the circumferential direction are provided. On the outer peripheral side surface of the sleeve 8, four longitudinal grooves 8f extending in the axial direction are provided at positions where they are connected to the respective lateral grooves 8e. When the shaft 6 is inserted into the sleeve 8, as the shaft 6 approaches the bottom portion 7b of the bearing holding portion 7a, the closed space formed therein is pressurized, so that the insertion of the shaft 6 becomes difficult. Since air is discharged to the outside from the communication hole formed by 8f and the inner peripheral side surface of the bearing holding portion 7a and the communication hole formed by the lateral groove 8e and the front surface of the thrust plate 12, the closed space Thus, the sleeve 8 can be inserted smoothly.

  Further, even if the operator mistakenly inserts the shaft 8 upside down when inserting the shaft 6 into the sleeve 8, the lower end portion of the large-diameter portion 2 a of the impeller 2 is placed on the lower end surface of the sleeve 8. This makes it possible to know whether the fan 1 has been assembled before the blower fan 1 is completed.

(Third embodiment)
Next, the ventilation fan 1 of 3rd Embodiment is demonstrated centering on difference with 1st Embodiment with reference to FIG.

  The sleeve 8 of the present embodiment is fixed to the bearing holding portion 7a via a cylindrical bearing holding member 18. The lower end portion of the bearing holding member 18 is formed with a thin portion 18a whose outer diameter is reduced compared to the upper end side. The magnet holder 14 includes a cup portion 14b in which the suction magnet 13 is accommodated, a fitting portion 14c that fits on the outer peripheral side surface of the thin portion 18a of the bearing holding member 18, and the cup portion 14b and the fitting portion. A stepped portion 14d that expands in the radial direction.

  In the magnet holder 14, the fitting portion 14c is press-fitted and fixed to the outer peripheral side surface of the thin portion 18a of the bearing holding member 18, closes the lower opening of the bearing holding member 18, and is press-fitted and fixed to the concave portion 7c of the bearing holding portion 7a. ing. The sleeve 8 is press-fitted and fixed to the inner peripheral side surface of the bearing holding member 18 so that the lower end surface of the sleeve 8 is in contact with the stepped portion 14 a of the magnet holder 14. That is, the magnet holder 14 itself is press-fitted and fixed in the concave portion 7c, and the sleeve 8 is brought into contact with the stepped portion 14a of the magnet holder 14 so that the magnet holder 14 has the sleeve 8 and the concave portion 7c. Since it is pinched and restricted in movement, it is firmly fixed to the bearing holding portion 7a.

  In the present embodiment, an assembly unit including the sleeve 8, the bearing holding member 18, the thrust plate 12, the suction magnet 13, and the magnet holder 14 is separately assembled, and the assembly unit is inserted into the bearing holding portion 7a for assembly. can do.

(Fourth embodiment)
Next, the ventilation fan 1 of 4th Embodiment is demonstrated centering on difference with 1st Embodiment with reference to FIG.

  In this embodiment, the retaining structure of the shaft 6 is configured not on the shaft 6 but on the lower side of the shaft 6 as in the first embodiment. That is, the retaining plate 19 (corresponding to the intermediate member) is an annular thin plate made of synthetic resin, and is fixed by being sandwiched between the flange portion 14 a of the magnet holder 14 and the lower end portion of the sleeve 8. The inner peripheral portion of the retaining plate 19 is accommodated in an annular recess 6 a provided on the outer peripheral side surface of the lower end portion of the shaft 6 to constitute a retaining structure for the shaft 6.

  Also in this configuration, since the magnet holder 14 is sandwiched between the sleeve 8 and the recess 7c via the retaining plate 19 and restricted in movement, the magnet holder 14 is firmly fixed to the bearing holding portion 7a. Note that the retaining structure on the upper side of the shaft 6 may be omitted.

(Fifth embodiment)
Next, a blower fan 1 according to a fifth embodiment will be described with reference to FIG. 7 focusing on differences from the first to fourth embodiments.

  This embodiment is greatly different from the first to fourth embodiments in that the bearing holding portion 7a is not in the shape of a bottomed cylinder, but has a configuration in which the lower end opening thereof is closed by the magnet holder 14. Here, the magnet holder 14 is integrated with the frame 7 by insert molding, but the back surface of the cup portion 14 b of the magnet holder 14 is exposed from the back surface of the frame 7. That is, the magnet holder 14 closes the central hole 7e formed by the inward protruding portion 7d protruding inward in the radial direction from the lower end opening of the bearing holding portion 7a. The back surface of the flange portion 14a of the magnet holder 14 is in contact with the stepped portion 7f at the tip of the inward projecting portion 7d, and the magnet holder 14 is positioned in the axial direction. The thrust plate 12 is in contact with the surface of the flange 14a, and the sleeve 8 is in contact with the thrust plate 12. As a result, the magnet holder 14 is sandwiched between the thrust plate 12 and the stepped portion 7f of the inward projecting portion 7d and the sleeve 8, and the magnet holder 14 is strengthened even when the bearing holding portion 7a is not a bottomed cylindrical shape. Can be fixed.

  As apparent from the present embodiment, the magnet holder 14 is not limited to the case where the magnet holder 14 is fixed to the bearing holding portion 7a by insert molding. For example, the magnet holder 14 has the same shape as the frame 7 shown in FIG. The present invention can also be applied to a configuration in which the magnet holder 14 is fixed to the frame 7 with the opening being opened by predetermined fixing means such as press-fitting, bonding, and welding.

(Sixth embodiment)
Next, a blower fan 1 according to a sixth embodiment of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view of the blower fan 1 according to the sixth embodiment of the present invention. Since the basic structure of the blower fan 1 of the present embodiment is the same as that of the first embodiment, the description will focus on differences from the first embodiment.

  The blower fan 1 includes an impeller 2 that is rotationally driven by an electric current supplied from the outside. The impeller 2 is provided with a plurality of blades 3 on the outer periphery of the cup portion 21 that opens to the lower side, a covered cylindrical rotor yoke 4a made of a magnetic material on the inner peripheral side surface of the cup portion 21, and the inner periphery of the rotor yoke 4a A cylindrical rotational drive magnet 5 is provided on the side surface, and a shaft 6 is press-fitted into the center of the rotor yoke 4a.

  The frame 7 has a horizontal portion that expands in a disk shape at a position facing the lower side in the axial direction of the impeller 2, and a bottomed cylindrical bearing holding portion 7 a is formed at the center of the horizontal portion. On the inner peripheral side surface of the cylindrical portion of the bearing holding portion 7a, a sleeve 8 is formed by impregnating a lubricating oil into a cylindrical porous metal obtained by baking magnetic powder and constituting a sliding bearing. It is press-fitted and fixed. The frame 7 is integrally formed of a synthetic resin with a wind tunnel portion (not shown) that surrounds the impeller 2 and forms an air flow path. The frame 7 may be formed from either metal or rigid resin.

  On the outer peripheral side surface of the cylindrical portion of the bearing holding portion 7a, there is a stator 9 in which a coil 92 is wound through upper and lower insulators 93, 94 formed of a synthetic resin on a stator core 91 formed by laminating a plurality of silicon steel plates. The fitting is fixed. The coil 92 is electrically connected to the circuit board 10 located on the lower side of the stator 9 via the conduction pin 11. A lead wire (not shown) for connecting to an external power source is drawn out from the circuit board 10.

  In the sleeve 8, the shaft 6 is inserted into an insertion hole 8 a provided in the center, and the inner peripheral side surface of the insertion hole 8 a and the outer peripheral side surface of the shaft 6 constitute a sliding bearing. When the shaft 6 is inserted into the insertion hole 8a, the lubricating oil oozes out from the inner peripheral side surface of the insertion hole 8a to reduce the friction with the shaft 6, and the shaft 6 is supported rotatably with respect to the sleeve 8. The The annular member 2b attached in the vicinity of the fastening portion between the shaft 6 and the rotor yoke 4a is formed so that a part of the upper insulator 93 of the stator 9 is hooked in the axial direction inside the sleeve retaining portion 931 protruding toward the inner diameter side. 8 is configured to prevent the shaft 6 from slipping off from the shaft 8. Since the outer diameter of the annular member 2b is larger than the inner diameter of the sleeve retaining portion 931, the sleeve retaining portion 931 can restrict the upward movement of the impeller 2 in the axial direction.

  A concave portion 8 b is formed on the upper end surface of the sleeve 8 so as to surround the periphery of the shaft 6. The annular member 2b is disposed so as to be accommodated in the recess 8b. Thereby, the lubricating oil which reached | attained the annular member 2b along the shaft 6 is discharge | released toward radial direction outward with the centrifugal force which acts on the annular member 2b. The discharged lubricating oil is collected in the recess 8b of the sleeve 8. Therefore, the lubricating oil does not flow out of the bearing through the shaft 6. Moreover, you may apply | coat an oil repellent to the surface of the cyclic | annular member 2b. In this case, the lubricating oil is discharged radially outward immediately after reaching the annular member 2b. Therefore, the lubricating oil can be recovered more effectively by the sleeve 8.

Further, the upper end surface of the sleeve 8 is opposed to the sleeve retaining portion 931 in the axial direction through a minute gap. The size of this minute gap is preferably 0.1 mm. Considering the tolerance, the upper limit is about 0.7 mm. As a result, in the unlikely event that the sleeve 8 moves axially upward from the bearing holding portion 7a, the upper end surface of the sleeve 8 contacts the sleeve retaining portion 931, and the sleeve 8 can be prevented from moving. . Since the sleeve 8 is press-fitted and fixed to the bearing holding portion 7a, it does not move in the axial direction. However, when there is a possibility that the inner diameter of the sleeve 8 is distorted when the sleeve 8 is press-fitted into the bearing holding portion 7a, the press-fitting allowance of the sleeve 8 to the bearing holding portion 7a may be reduced. However, when the press-fitting allowance decreases, the press-fitting strength decreases. In such a case, the sleeve 8 may move in the axial direction when the blower fan 1 receives a strong impact from the outside.

  In the present embodiment, the flange 14a extending from the opening end of the cup portion 14b of the magnet holder 14 is disposed on substantially the same surface as the bottom portion 7b of the bearing holding portion 7a, or is axially lower than the bottom portion 7b. Is arranged. This is different from the first embodiment. That is, both the flange 14a and the cup portion 14b of the magnet holder 14 are disposed in the recess 7c provided in the bottom portion 7b. However, the magnet holder 14 is disposed between the sleeve 8 and the bottom portion 7b, similarly to the first embodiment, thereby restricting the movement of the magnet holder 14 in the axial direction.

  Further, the annular member 2 b constituting the shaft retaining structure is disposed in a recess 8 b provided on the upper end surface in the axial direction of the sleeve 6. Therefore, the axial length, that is, the height of the blower fan 1 can be reduced, and at the same time, the space in the blower fan 1 can be used effectively while securing the volume of the bearing.

  As mentioned above, although the embodiment of the motor concerning the present invention was illustrated using the ventilation fan, the range of the present invention is not limited to this but various changes are possible.

  For example, the magnet holder 14 of the first to fourth embodiments is press-fitted and fixed to a predetermined portion of the bearing holding portion 7a. However, the magnet holder 14 may be fixed to the bearing holding portion 7a integrally by insert molding or the like. It is good also as a fixed structure.

  Although the magnet holder 14 is configured to be fixed to the recess 7c of the bearing holding portion 7a by press-fitting, bonding, insert molding, or the like, it is not necessarily fixed to the recess 7c.

  The attracting magnet 13 has a configuration in which the shaft 6 is directly attracted. However, when using the shaft 6 made of a nonmagnetic material, an annular member made of a magnetic material is attached to the lower end portion of the shaft 6. Thus, a similar configuration can be realized.

  Although the motor of each embodiment has exemplified the blower fan 1, it is applicable to various motors such as a motor for rotationally driving a recording disk and a motor for rotationally driving a color wheel for displaying an image. Can do. Each motor may be one in which a stator and a rotation driving magnet face each other in the axial direction.

It is sectional drawing which shows the whole ventilation fan of 1st Embodiment which concerns on this invention. It is sectional drawing to which the principal part of the ventilation fan shown in FIG. 1 was expanded. It is sectional drawing which shows the principal part of the ventilation fan of 2nd Embodiment which concerns on this invention. It is the top view which looked at the thrust board in the bearing holding part of the ventilation fan shown in FIG. 3 from upper direction. It is sectional drawing which shows the principal part of the ventilation fan of 3rd Embodiment which concerns on this invention. It is sectional drawing which shows the principal part of the ventilation fan of 4th Embodiment which concerns on this invention. It is sectional drawing which shows the principal part of the ventilation fan of 5th Embodiment which concerns on this invention. It is sectional drawing which shows the principal part of the ventilation fan of 6th Embodiment which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Blow fan 2 Impeller 4 Rotor yoke 5 Rotation drive magnet 6 Shaft 7 Frame 8 Sleeve 9 Stator 10 Circuit board 11 Conduction pin 12 Thrust plate 13 Suction magnet 14 Magnet holder 15 Annular space 16 Felt 18 Bearing holding member 19 Retaining member

Claims (22)

A rotor portion having a shaft and a rotational drive magnet and rotating around a rotation axis;
A stator having a coil that is disposed at a position facing the rotation driving magnet in the radial direction or the axial direction of the rotation shaft, and that rotates the rotor portion;
A cylindrical sleeve that has an insertion hole through which the shaft is inserted, and that forms a bearing with the outer peripheral surface of the shaft so as to rotatably support the rotor portion with respect to the stator;
A bearing holding portion having a bottomed cylindrical cylindrical portion for holding the stator on the outer peripheral side surface and holding the sleeve on the inner peripheral side surface, and a concave portion opening toward the sleeve side at the bottom portion of the cylindrical portion;
A suction magnet that is disposed to face an end surface on the insertion direction side of the shaft, and that magnetically attracts the end surface to the insertion direction side;
The cup-shaped recess that is formed of a magnetic material and accommodates the suction magnet so as to surround the opposite surface of the suction magnet facing the shaft and the radially outer peripheral side surface is axially disposed in the concave portion of the bearing holding portion. A magnet holder to be positioned,
The motor, wherein the magnet holder is sandwiched between the sleeve and the recess. A rotor portion having a shaft and a rotational drive magnet and rotating around a rotation axis;
A stator having a coil that is disposed at a position facing the rotation driving magnet in the radial direction or the axial direction of the rotation shaft, and that rotates the rotor portion;
A cylindrical sleeve that has an insertion hole through which the shaft is inserted, and that forms a bearing with the outer peripheral surface of the shaft so as to rotatably support the rotor portion with respect to the stator;
A cylindrical portion with a bottom that holds the stator on the outer peripheral side and holds the sleeve on the inner peripheral side, and an inward protruding portion that protrudes radially inward on the inner peripheral side of the bottom of the cylindrical portion A bearing holder;
A suction magnet that is disposed to face an end surface on the insertion direction side of the shaft, and that magnetically attracts the end surface to the insertion direction side;
A cup portion that is formed of a magnetic material and encloses the suction magnet so as to surround the opposite side of the suction magnet facing the shaft and the radially outer peripheral side surface, and protrudes radially outward on the outer peripheral side surface of the cup portion And a magnet holder that is positioned in the axial direction on the inward protruding portion of the bearing holding portion,
The motor, wherein the magnet holder is sandwiched between the sleeve and the inward protruding portion.   The motor according to claim 1, wherein the magnet holder is in contact with the sleeve.   The motor according to claim 1, wherein an intermediate member is interposed between the magnet holder and the sleeve.   The motor according to claim 4, wherein the intermediate member is a thrust plate that is disposed on a surface of the attraction magnet facing the shaft and slidably supports the shaft.   The motor according to claim 4, wherein the intermediate member is a retaining member that prevents the shaft from being detached from the sleeve. The upper end of the shaft is provided with a large diameter portion larger than the diameter of the insertion hole of the sleeve,
The upper end of the sleeve has an annular recess that accommodates the lower end portion of the large-diameter portion while the upper opening end of the insertion hole is located below the upper end surface of the sleeve,
The lower end of the sleeve is formed in a flat shape so as to include a position having the same diameter as or smaller than the outer diameter of the large-diameter portion. The motor described.   The motor according to claim 1, wherein the sleeve is in contact with an opening end of the magnet holder.   8. The magnet holder according to claim 1, wherein the magnet holder has a stepped portion protruding inward from the opening end portion, and the sleeve abuts on the stepped portion of the magnet holder. motor.   The sleeve is formed of a porous material impregnated with a lubricating oil, and a lubricating oil-impregnated member formed of a porous material impregnated with the lubricating oil is provided in close contact with the sleeve. The motor according to claim 1, wherein: The sleeve is held by the bearing holding portion via a cylindrical bearing holding member,
The motor according to claim 1, wherein the magnet holder is fixed to an outer peripheral side surface of the bearing holding member so as to close a lower end opening of the bearing holding member.   The motor according to claim 1, wherein an impeller that generates an air flow by rotation is provided in the rotor portion. A rotor portion having a shaft and a rotational drive magnet and rotating around a rotation axis;
A stator having a coil that is disposed at a position facing the rotation driving magnet in the radial direction or the axial direction of the rotation shaft, and that rotates the rotor portion;
A cylindrical sleeve that has an insertion hole through which the shaft is inserted, and that forms a bearing with the outer peripheral surface of the shaft so as to rotatably support the rotor portion with respect to the stator;
A bearing holding portion having a bottomed cylindrical cylindrical portion for holding the stator on the outer peripheral side surface and holding the sleeve on the inner peripheral side surface, and a concave portion opening toward the sleeve side at the bottom portion of the cylindrical portion;
A suction magnet that is disposed to face an end surface on the insertion direction side of the shaft, and that magnetically attracts the end surface to the insertion direction side;
The cup-shaped recess that is formed of a magnetic material and accommodates the suction magnet so as to surround the opposite surface of the suction magnet facing the shaft and the radially outer peripheral side surface is axially disposed in the concave portion of the bearing holding portion. A magnet holder to be positioned,
The motor , wherein the magnet holder is disposed between the sleeve and the bottom of the cylindrical portion in the axial direction, and overlaps the sleeve and the bottom of the cylindrical portion in the axial direction .
  The sleeve is formed of a porous material impregnated with a lubricating oil, and a lubricating oil-impregnated member formed of a porous material impregnated with the lubricating oil is provided in close contact with the sleeve. The motor according to claim 13.   A small-diameter portion having an outer diameter smaller than the inner peripheral surface of the bearing holding portion is formed on the magnet holder mounting side in the axial direction of the sleeve, and an oil retaining material is disposed on the outer peripheral surface of the small-diameter portion. The motor according to claim 14.   The sleeve retaining member that is axially opposed to the end surface on the axial end side of the sleeve in the axial direction via a minute gap is attached to the axially open end side of the bearing holding portion. The motor according to 14 or 15.   The motor according to claim 16, wherein the size of the minute gap between the sleeve retaining member and the end face on the opening end side of the sleeve is 0.7 mm or less.   16. The motor according to claim 14, wherein a sleeve retaining member that is in contact with an end face of the sleeve in the axial direction on the opening end side is attached to the axial opening end side of the bearing holding portion.   The motor according to any one of claims 14 to 18, wherein the stator includes a coil, an insulator, and a stator core, and the sleeve retaining member and the insulator are formed continuously. .   The motor according to any one of claims 14 to 19, wherein a concave portion is formed on an end surface of the sleeve in the axial direction on the opening end side so as to surround the shaft.   21. The motor according to claim 20, wherein an annular member is attached to an outer peripheral side surface of the shaft so that a part thereof is located inside the recess.   The outer diameter of the annular member is larger than the inner diameter of the inner peripheral surface of the sleeve retaining member, and the annular member is disposed between the sleeve retaining member and the sleeve in the axial direction. The motor according to claim 21.

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