JP2002010564A - Dc brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a high quality DC brushless motor which can keep a rotor at a proper position even if an external force such as an impact, etc., is applied. SOLUTION: This DC brushless motor is an outer-rotor type DC brushless motor in which the rotor shaft 22 of the rotor 21 is supported rotatably by 1st and 2nd bearings 18 and 19 which are press-fitted to the stator attaching part 12 of the motor housing 11 so as to be separated from each other. A large diameter part 18b with a contact plane 18c is provided in the 1st bearing 18 placed at a position close to the opposite-to-output end 22b of the rotor shaft 22. The contact plane 18c is pressed against the tip plane of the stator attaching part 12. With this constitution, the 1st bearing 18 is positioned so as not to be moved toward the output end 22a of the rotor shaft 22 when an impact F is applied.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CD-ROM,
The present invention relates to a DC brushless motor used for rotationally driving an information recording medium such as a VD, or for rotationally driving a rotary cleaning body built in a suction opening of an electric vacuum cleaner.

[0002]

2. Description of the Related Art Since a DC brushless motor can be made small and lightweight, even if it is incorporated in a suction port of a vacuum cleaner, for example, it does not cause a significant increase in the weight or external shape of the suction port. The power is suitable for rotationally driving a rotary cleaning body incorporated in the suction port body.

FIGS. 5A and 5B show a conventional brushless motor which can be incorporated in a suction port. In this figure, 1 is a motor housing, 2 is a stator fitted and mounted on a stator mounting portion 1a of the housing 1, 3 is a rotor, 4 and 5 are bearings supporting the rotor 3, 6 is a rotor rotational position detector, Reference numeral 7 denotes a motor case.

A stator 2 formed by winding a stator coil around a laminated iron core is mounted by press-fitting a center hole 2a into an outer peripheral surface of a cylindrical stator mounting portion 1a. The rotor 3 has a cup-shaped rotor yoke 3b connected to the non-output end of the rotating shaft 3a via a rotor bush 3c, and a ring-shaped rotor magnet 3d facing the outer peripheral surface of the stator 2 on the inner peripheral surface of the rotor yoke 3b. Mounted and formed. The rotor magnet 3d is divided into a plurality of regions in the circumferential direction, and regions adjacent to each other are magnetized with different polarities.
Magnetization is performed in the thickness direction of the rotor magnet 3d.

[0005] A pair of bearings 4 and 5 have a stator mounting portion 1a.
Are axially spaced apart from each other in the axial direction of the mounting portion 1a, and rotatably support a rotor shaft 3a passing through the stator mounting portion 1a. Rotor shaft 3
A suitable number of liners 8 are sandwiched between the bearing 5 near the non-output end and the rotor bush 3c.

A circuit board 9 is provided on the inner surface of the motor housing 1.
The rotor rotational position detector 6 is mounted on the substrate 9. The detector 6 composed of a Hall element or the like faces the end face of the rotor magnet 3d, and detects the magnetic pole of the magnet 3d. The motor case 7 covers the rotor 3 and is caulked to the motor housing 1, and a thrust bearing 10 for supporting the non-output end of the rotor shaft 3a is attached to a closed wall 7a of the case 7.

The inner space of the stator mounting portion 1a of the DC brushless motor having the above-described structure has the same diameter over substantially the entire length, and the diameter of the bearing 4 near the output end of the rotor shaft 3a is slightly enlarged. A pair of bearings 4 and 5 are press-fitted at positions other than the diameter end. No measures have been taken to stop the pair of bearings 4 and 5 from moving in the axial direction of the stator mounting portion 1a.

[0008] By the way, the suction opening of the vacuum cleaner is not used stationary, but is used while being moved along the floor or the like. There are many cases, and there are also cases where it falls on the floor or the like.

Accordingly, an impact force also acts on the DC brushless motor built in the suction port. If the direction of action of this impact force is the direction of arrow Z in FIG. 5A, that is, if the impact force acts to move the entire rotor 3 toward the output end of the rotor shaft 3a, the impact force is It acts on the bearing 5 via the liner 8. However, the conventional DC brushless motor does not take measures to stop the movement of the bearing 5 as described above.
May be moved in the arrow Z direction. At this time, the rotor shaft 3a slides axially through the center hole of the other bearing 4.

When the entire rotor 3 is moved in the direction of the arrow Z in this manner, the closing wall 3be of the rotor yoke 3b interferes with the stator coil 2b approaching the rotor yoke 3b, and the rotor rotational position where the rotor magnet 3d approaches the rotor coil 3b. It interferes with the detector 6 and causes the functions of the stator 2 and the rotor rotational position detector 6 to be impaired. Therefore, in the case of a DC brushless motor used under conditions that are susceptible to an impact force, such as when the motor is used by being incorporated into a suction port body, it is required to take care not to suffer the above-mentioned adverse effects due to the impact force. ing.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-quality DC brushless motor capable of holding a rotor at an appropriate position even when an external force such as an impact force is applied.

[0012]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a pair of bearings which are press-fitted and spaced apart from each other at a stator mounting portion of a motor housing and rotatably support a rotor shaft of a rotor. And positioning means for stopping the first bearing near the output end of the rotor shaft in the direction of the output end of the rotor shaft.

The present invention is characterized in that a collar is sandwiched between the two bearings, and a stopper convex portion for positioning a second bearing near an output end of the rotor shaft is provided integrally with the motor housing, and the first bearing is provided. Including stopping the movement. Further, according to the present invention, the first bearing is provided with a contact surface formed of a surface along a direction perpendicular to the axial direction of the first bearing, and the contact surface is brought into contact with a tip end surface of the stator mounting portion. And stopping the first bearing.
In the case where the first bearing is provided with an abutting surface formed of a surface along a direction orthogonal to the axial direction of the first bearing, the first bearing may be used.
It is preferable to press-fit the outer peripheral surface of the bearing into the center hole of the stator. In this embodiment, the first bearing may have a caulking portion projecting outside the center hole of the stator, and this portion may be deformed to be caulked at the hole edge of the center hole.

According to the present invention, there is provided a pair of bearings for rotatably supporting the rotor shaft even when an external force such as an impact force is applied in a direction to move the entire rotor toward the output end of the rotor shaft. The first bearing near the non-output end of the rotor shaft is prevented by the positioning means from moving toward the output end of the rotor shaft, so that the entire rotor at an appropriate position can be prevented from moving in the direction in which the external force acts.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS.

FIG. 2 is a sectional view showing a DC brushless motor M according to the first embodiment. In the figure, reference numeral 11 denotes a motor housing made of a metal, for example, a light metal such as an aluminum alloy. The motor housing 11 integrally has a stator mounting portion 12 having both ends opened at a substantially central portion thereof.

On the inner surface of the motor housing 11, a rotor rotational position detector 13 composed of a Hall element or the like is mounted. That is, the detector 13 is mounted on a circuit board 14 made of a flexible printed wiring board or the like, and the circuit board 14 is mounted on the inner surface of the motor housing 11.

The inner space of the stator mounting portion 12 has the same diameter over substantially the entire length. The fact that the inner space portion of the stator mounting portion 12 has the same diameter is excellent in that the inner space portion can be machined by one operation from one direction, so that machining is easy. In addition, chamfers represented by the tip of the stator mounting portion 12 are provided at the opening edges at both ends of the stator mounting portion 12, respectively. Stator mounting part 12
The outer diameter of the stator mounting portion 12 is sequentially different in three stages from the base side to the tip side, and the difference in these outer diameters causes the stator mounting portion 12 to have a stator positioning intermediate outer surface. Is formed.

The small-diameter portion 12 on the distal end side of the stator mounting portion 12
A central hole 15a of a stator 15 to be press-fitted into the outer peripheral surface of b is fitted, and the stator 15 is positioned by the step 12a. The stator 15 is formed by winding a plurality of stator coils 17 around an iron core 16 formed by laminating a predetermined number of laminated steel plates and connecting them with rivets or the like. Each coil 17 is wound around a plurality of slots (not shown) of the iron core 16 with an insulating material (not shown) insulated, thereby providing, for example, a three-phase coil. A part of the stator coil 17 wound around the iron core 16 projects from both sides in the thickness direction of the iron core 16.

A first bearing 18 and a second bearing 19 are press-fitted and mounted on the stator mounting portion 12 at a distance in the axial direction. The first bearing 18 is disposed on the distal end side of the stator mounting portion 12, and the second bearing 19 is disposed on the stator mounting portion 12.
It is arranged at the base side. For these bearings 18 and 19, for example, radial bearings made of a copper alloy or an oil-impregnated sintered bearing can be suitably used, but radial ball bearings or the like can also be used. The illustrated second bearing 19 has a cylindrical shape.

As shown in detail in FIG. 2B, the first bearing 1
Reference numeral 8 has a small-diameter portion 18a and a large-diameter portion 18b. The step surface of the large-diameter portion 18b on the small-diameter portion 18a side is a contact surface 18 serving as a positioning means.
c. The contact surface 18c is a surface that extends along a direction orthogonal to the axial direction of the first bearing 18, and comes into contact with the distal end surface of the stator mounting portion 12 as the small-diameter portion 18a is pressed into the stator mounting portion 12. Is to be touched.

The outer diameter of the large-diameter portion 18b is set so as to be pressed into the center hole 15a of the stator 15, and the end surface of the large-diameter portion 18b on the side opposite to the small-diameter portion 18a except the peripheral portion thereof. It is recessed. The portion of the large-diameter portion 18b on the contact surface 18c side is press-fitted into the center hole 15a as the small-diameter portion 18a is press-fitted into the stator mounting portion 12, and the remaining caulking of the large-diameter portion 18b not pressed into the center hole 15a. The portion 18be projects outside the center hole 15b. A plurality of or all of the caulked portions 18be are plastically deformed by press working so as to spread radially outward from a state shown by a two-dot chain line in FIG. 2B as shown by a solid line in the figure. By this processing, the caulking portion 18be is caulked at the hole edge of the center hole 15a of the stator 15, and the stator 1 is formed by this portion 18be and the step 12a.
5 are sandwiched from both sides in the thickness direction.

The two bearings 18 and 19 rotatably support a rotor 21 that covers the stator 15. The rotor 21 includes a rotor shaft 22, a rotor yoke 23, and a rotor magnet 24.

The rotor shaft 22 extends through the stator mounting portion 12 and is rotatably supported by the mounting portion 12 via a pair of bearings 18 and 19. The end of the rotor shaft 22 on the second bearing 19 side is used as an output end 22a,
The end of the rotor shaft 22 on the bearing 18 side is used as a non-output end 22b.

The rotor yoke 23 has a cup shape large enough to cover the stator 15 and has a rotor shaft 2 at the center of a closed wall 23a via a metal rotor bush 25.
The two non-output ends 22b are connected. That is, the rotor bush 25 has the caulked portion 25a and the closed wall 2
The press-fitting portion 25a is press-fitted into a connection hole 23b formed in the center of 3a, and after this press-fitting, the caulked portion 25a is bent so as to overlap the hole edge of the connection hole 23b (FIG. 2 shows a bent state). ) Is fixed to the closing wall 23a. The center hole 2 of the rotor bush 25
The non-output end 22b of the rotor shaft 22 is press-fitted and fixed to 5b. The non-output end 22b penetrates the center hole 25b, and the tip end surface is formed as a part of a spherical surface.

A rotor magnet 24 is mounted on the inner peripheral surface of the cylindrical circumferential wall 23b of the rotor yoke 23 via an adhesive. The rotor magnet 24 has a ring shape and is magnetized to a plurality of poles corresponding to the number of slots of the iron core 16.

After assembling the rotor 21 having the above structure, the bearing 1 already fixed to the stator mounting portion 12 is used.
The rotor shaft 22 is inserted into bearing holes 8 and 19 provided in the center thereof.
Is inserted from the output end 22a side. In this mounting, one or more liners 26 are sandwiched between the first bearing 18 and the rotor bush 25. The diameter of the liner 26 is smaller than the diameter of the recess of the first bearing 18.

By assembling the rotor 21 as described above,
As shown in FIG. 2A, the end face of the rotor magnet 24 on the inner surface side of the motor housing 11 is close to and opposed to the rotor rotational position detector 13 and the rotor yoke 23
Of the stator 15 protrudes toward the wall 23a and is close to and opposed to the stator coil 17 of the stator 15.

In FIG. 2, reference numeral 27 denotes a cup-shaped metal motor case provided to accommodate the rotor 21.
A plurality of portions of the opening edge are caulked to the peripheral portion of the motor housing 11. A caulking portion is shown at 27a. A thrust bearing 28 is attached to the center of the closing wall 27b of the motor case 27. The tip of the non-output end portion 22b of the rotor shaft 22 is supported in contact with the bearing 28.

FIG. 1 shows a DC brushless motor M having the above configuration.
1 shows a vacuum cleaner provided with: In the figure, reference numeral 31 denotes a vacuum cleaner main body in which an electric blower (not shown) is accommodated, and dust collecting bags are respectively housed so as to be able to be taken in and out of the dust collecting chamber on the upstream side of suction of the blower, and 32 communicates with the dust collecting chamber. A freely deformable dust suction hose connected to the vacuum cleaner main body 31;
Reference numeral 33 denotes a rigid hand handle connected to the tip of the dust suction hose 32. Reference numeral 34 denotes a hard extension pipe detachably connected to the handle 33 at hand, and reference numeral 35 denotes a suction port body detachably connected to the tip of the extension pipe 34.

The suction opening body 34 has a built-in rotary cleaning body 36 opposed to a suction opening (not shown) opened on the lower surface thereof, and the DC brushless motor M for driving the cleaning body 36 to rotate. Have been. The motor M is directly connected to, for example, the rotary cleaning body 36. Driving and stopping of the DC brushless motor M are performed by operating buttons on the operation unit 33a of the hand handle 33.

When the vacuum cleaner is used or the like, an external force such as an impact force may be applied to the suction port body 35 depending on how the suction port body 35 is moved. Accordingly, when an external force such as an impact force in the direction of arrow F in FIG. 2 acts on the built-in DC brushless motor M, the rotor 21
Try to be moved in the direction.

However, in the DC brushless motor M described above, the first bearing 18 supporting the non-output end 22b side of the rotor shaft 22 has a contact surface 18c of the large diameter portion 18b.
Is mounted in contact with the distal end of the small diameter portion 12b of the stator mounting portion 12.

For this reason, the first bearing 1 is connected via the liner 26.
Even if the entire rotor 21 continuous with the rotor 8 is moved in the direction of the arrow F with the first bearing 18, the contact surface 18 c of the first bearing 18 is fixed to the stator mounting portion 12 of the fixed motor housing 11. Since the first bearing 18 is positioned in the axial direction as described above, the first bearing 18 is prevented from moving in the arrow F direction. Therefore, the rotor 21 is prevented from being moved so as to approach the motor housing 11 side, and the rotor 21 can be held at an appropriate position.

As described above, the positioning means for stopping the movement is such that the large diameter portion 18b is provided on the first bearing 18 and the contact surface 18c of the large diameter portion 18b is provided at the tip of the stator mounting portion 12. , And can be easily realized without requiring special parts.

As described above, even if an impact force or the like is applied to move the rotor 21 in the direction of arrow F in FIG. 2, the rotor 21 may be displaced from the proper position with the first bearing 18. The closed wall 23 of the rotor yoke 23
a may interfere with the stator coil 17 approaching it, or the rotor magnet 24 may interfere with the rotor rotational position detector 13 approaching it, thereby impairing the functions of the stator 15 and the rotor rotational position detector 13. Absent.

As described above, the DC brushless motor M is excellent in impact resistance. Therefore, even if the suction port 35 on which the motor M is mounted is roughly handled, the DC brushless motor M is displaced from the proper position. It is possible to suppress the failure of the motor M.

The large diameter portion 1 which forms the maximum diameter of the first bearing 18
8b is press-fitted into the center hole 15a of the iron core 16 of the stator 15, so that the first bearing 18 is mounted concentrically with the stator 15 based on the center hole 15a. The rotor shaft 22 of the rotor 21 is supported through the bearing hole at the center of the first bearing 18, and the rotor shaft 22 is mounted concentrically with the first bearing 18. Therefore, concentricity between the stator 15 and the rotor 21 can be easily obtained, and
A slight magnetic gap between the outer peripheral surface of the stator 15 and the rotor magnet 24 can be provided with high accuracy.

Further, the swaging portion 18be of the first bearing 18
Is crimped so as to spread to the outer peripheral side, and the starter mounting portion 1
Since the stator 15 is mounted on the motor housing 11, no special parts are required for fixing the stator 15 to the motor housing 11, and the stator 15 can be fixed with a simple structure.

In the first embodiment in which the stator 15 is crimped as described above, the outer peripheral surface of the small diameter portion 12b of the stator mounting portion 12 is
May be provided with the center hole 15a. In such a case, it is not necessary to process the inner peripheral surface of the center hole 15a into a predetermined flatness. Further, in the configuration of the first embodiment, the first bearing 18 is not formed in a stepped structure, and its entire outer peripheral surface is formed by a circumferential surface having the same diameter as the large diameter portion. The end face on the insertion end side of the first bearing 18, that is, the peripheral portion of the contact surface formed of a surface orthogonal to the axial direction of the first bearing 18 is brought into contact with the tip of the stator mounting portion 12, and the first bearing 18 is attached to the stator mounting portion. 12 may be arranged so as to be continuous without being press-fitted.

FIG. 3 shows a second embodiment of the present invention. Since this embodiment is basically the same as the first embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the description of the configuration and operation is omitted. The different parts will be described. The difference between the second embodiment and the first embodiment is the positioning means.

The positioning means in the second embodiment comprises a stopper projection 31 integral with the motor housing 11 and a cylindrical collar 32. The stopper convex portion 31 is formed as a flange-shaped convex portion that is continuous in the circumferential direction along the inner peripheral surface of the mounting portion 12 inside the stator mounting portion 12, and is closer to the output end 22 a of the rotor shaft 22. Abuts on the end face of the second bearing 19 disposed at the second position. Thereby, the rotor 21
When the second bearing 19 is to be moved in the direction of the arrow F, the second bearing 19 is positioned. The collar 32 made of metal or the like is used as the first and second bearings 1 each having a cylindrical shape.
It is sandwiched between 8 and 19. The configuration other than the points described above is the same as that of the first embodiment.

In the second embodiment, the positioning is performed on the stopper projection 31 of the motor housing 11 via the first bearing 18 via the second bearing 19 and the collar 32.
Even if an impact force or the like that attempts to move the rotor 21 in the direction of arrow F in FIG. 3 acts, the rotor 21 is prevented from moving from an appropriate position with the first bearing 18. Therefore, the object of the present invention can be solved also in the second embodiment. In addition, in the second embodiment, the two bearings 1 sandwiching the collar 32 with respect to the stopper projection 31 in assembly are used.
Since the positions 8 and 19 can be positioned at one time, the assembling property is good.

FIG. 4 shows a third embodiment of the present invention. Since this embodiment is basically the same as the first embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the description of the configuration and operation is omitted. The different parts will be described. The difference between the third embodiment and the first embodiment is the positioning means.

The positioning means in the third embodiment is formed by a stopper projection 35 integrated with the motor housing 11. The protrusion 35 is continuous with the inner space of the stator mounting portion 12 in the circumferential direction along the inner peripheral surface of the mounting portion 12 and occupies most of the axially intermediate portion of the stator mounting portion 12. It is formed. Then, the cylindrical first bearing 1 is brought into contact with one end surface of the stopper convex portion 35.
8 is positioned, and the cylindrical second bearing 19 is positioned in contact with the other end surface of the stopper projection 35. The configuration other than the points described above is the same as that of the first embodiment.

In the third embodiment, since the first bearing 18 is positioned by the stopper projection 35 projecting from the inner peripheral surface of the stator mounting portion 12, the rotor 21 is moved in the direction of arrow F in FIG. Even if an impact force or the like acts, the rotor 21 is prevented from moving from an appropriate position with the first bearing 18. Therefore, the object of the present invention can be solved also in the third embodiment.

[0047]

According to the first to fifth aspects of the present invention, even if an external force such as an impact force is applied to move the entire rotor toward the output end of the rotor shaft supported by the pair of bearings, Since the first bearing near the non-output end of the rotor shaft can be prevented from moving toward the output end of the rotor shaft, the rotor can be held at an appropriate position regardless of the action of the external force. Therefore, interference between the rotor yoke and the stator coil, which are close to each other, and between the rotor magnet, which is similarly close to the rotor, and the rotor rotational position detector are prevented, and a high-quality DC brushless motor is provided. it can.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a vacuum cleaner having a suction port in which a brushless motor according to a first embodiment of the present invention is incorporated.

FIG. 2A is a sectional view showing a brushless motor according to the first embodiment. FIG. 2B is an enlarged cross-sectional view showing a Y part in FIG.

FIG. 3 is a sectional view showing a brushless motor according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a brushless motor according to a third embodiment of the present invention.

FIG. 5A is a sectional view showing a brushless motor according to a conventional example. FIG. 5B is a sectional view showing a rotor included in the brassless motor of FIG.

[Explanation of symbols]

 M: DC brushless motor 11: Motor housing 12: Stator mounting portion 13: Rotor rotational position detector 15: Stator 15a: Center hole of the stator 16: Iron core 17: Stator coil 18: First bearing 18a: Small diameter portion of the first bearing 18b: Large diameter portion of the first bearing 18c: Contact surface of the first bearing 18be: Caulked portion of the first bearing 19 ... Second bearing 21: Rotor 22: Rotor shaft 22a: Output end of the rotor shaft 22b: Rotor shaft 23: rotor yoke 24: rotor magnet 31, 35: stopper projection 32: collar

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02K 29/08 H02K 29/08 F term (Reference) 5H019 BB05 BB15 BB20 BB22 BB23 CC04 DD01 EE14 5H605 BB05 BB19 CC03 CC04 CC10 DD05 EA07 EA19 EB03 EB05 EB06 EB08 EB12 EB16 GG03 5H621 BB07 GA01 HH03 JK08 JK17 JK19 5H622 CA01 CA05 CA10 PP05 PP19

Claims (5)

[Claims] A motor housing having a stator mounting portion having both ends opened; a stator having an iron core and a stator coil wound around the core; and a stator mounted on the stator mounting portion; First and second bearings press-fitted and arranged apart from each other in the axial direction; a rotor shaft rotatably supported by these bearings and penetrating the stator mounting portion; a non-output end of the rotor shaft covering the stator; A rotor having a cup-shaped rotor yoke connected to the rotor, a rotor magnet attached to an inner peripheral surface of the yoke so as to face an outer peripheral surface of the stator, and a motor housing opposed to an end surface of the rotor magnet. A DC brushless motor having a rotor position detector attached thereto, wherein DC brushless motor of the first bearing, characterized by providing the positioning means for stopping movement to the output end direction of the rotor axis. 2. The method according to claim 1, wherein the positioning means includes a collar sandwiched between the two bearings, and a stopper convex portion provided integrally with the motor housing and positioning the second bearing near an output end of the rotor shaft. The DC brushless motor according to claim 1, wherein the DC brushless motor is formed. 3. The positioning means is provided on the first bearing along a direction orthogonal to the axial direction of the first bearing, and is a contact surface that comes into contact with a tip end surface of the stator mounting portion. The direct current brushless motor according to claim 1, wherein: 4. The DC brushless motor according to claim 3, wherein an outer peripheral surface of the first bearing is press-fitted into a center hole of the stator. 5. The invention according to claim 4, wherein said first bearing has a caulking portion projecting outside a center hole of said stator, and said portion is deformed to be caulked at a hole edge of said center hole. DC brushless motor as described.