JP2003032987A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor which can be manufactured at a cost lower than the conventional case, and to realize miniaturization. SOLUTION: This motor is equipped with an almost cylindrical housing, a sleeve bearing fixed to the inner peripheral surface of the housing, a shaft which is retained rotatably by the housing via the sleeve bearing, a rotor which has a rotor magnet and is fixed to one end portion of the shaft, and a stator which faces the rotor magnet and is installed on the outer peripheral surface of the housing. The housing is formed by plastic working of sheet metal, an outward step part is disposed on the outer peripheral part of the housing and abuts against the stator, thereby performing positioning in the axial direction; and a fixing part, for fixing the motor to an application apparatus for mounting, is disposed on one end of the housing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor used for driving a drum in a copying machine or the like, and a housing for a bearing thereof.

[0002]

2. Description of the Related Art Conventionally, for example, a brushless motor is known as a motor used for the above-mentioned applications. 3A and 3B are views showing the structure of such a conventional brushless motor, in which FIG. 3A is a front vertical sectional view and FIG. 3B is a bottom view. In the figure, reference numeral 1 is a mounting plate which serves as a base for mounting at a required place in an applicable device such as the copying machine. The substantially cylindrical housing 3 has its lower end penetrating a mounting hole 2 formed in the mounting plate 1 and fixed by caulking the peripheral edge portion.

A shaft 9 is rotatably supported on the inner surface of the housing 3 via a pair of upper and lower ball bearings 7, 8. A cup-shaped rotor 10 is fixed to the upper end portion of the shaft 9 led out from the upper end of the housing 3 by press fitting or the like, so that the rotor 10 integrally rotates around the shaft 9. An annular rotor magnet 11 is fitted and fixed to the inner peripheral surface of the outer peripheral wall of the rotor 10.

On the other hand, on the outer peripheral surface of the housing 3, a stator 12 in which a stator coil 14 is wound around a stator core 13 is externally fitted and fixed so as to face the rotor magnet 11 with a slight gap, and a screw 17 is provided. It is fixed by. The ball bearing 7 is held so as to be sandwiched between the inner peripheral portion of the rotor 10 on the upper surface of the inner ring and the stepped portion of the housing 3 on the lower surface of the outer ring. The ball bearing 8 is held so as to be sandwiched between the disc spring 24a on the stepped portion of the housing 3 on the upper surface of the outer ring and the stopper ring 24 on the lower surface of the inner ring.
Further, on the flange portion 19 of the housing 3, a circuit board 20 on which required electronic components are mounted and a rotation drive circuit of the rotor 10 and a coil current control circuit for the stator 12 are formed is fixed by screws 5. There is.

In addition, the circuit board 20 is attached to the mounting plate 1 with screws 6 as well.
It is fixed by. That is, the tongue piece 1b is provided at one location on the peripheral portion of the mounting plate 1, and the circuit board 20 is fixed to the mounting plate 1 by the screw 6 in the screw hole 1ba formed therein. In addition, tongue pieces 1c are provided at the four corners of the mounting plate 1, and the mounting plate 1 is mounted on the applied device side through holes 1ca formed therein.

Screw teeth 21 are integrally formed on the lower end of the shaft 9 extending from the housing 3. When the brushless motor is attached to the applied device, a transmission gear (not shown) such as a reduction mechanism of the applied device is meshed with and connected to the screw teeth 21. The brushless motor is generated between the stator 12 and the rotor magnet 11 by supplying a drive current (excitation current) to the stator coil 14 of the stator 12 from the external drive power source via the control circuit of the circuit board 20. The rotor 10 is attracted by the magnetic attraction and repulsive force.
A rotational force is generated in the shaft 10, and the rotational force of the rotor 10
It is transmitted to the rotational drive load of the applied device through the screw teeth 21 and the transmission gear of the.

[0007]

However, as described above, the housing 3 needs various concaves and convexes for mounting the pair of ball bearings 7 and 8, the stator 12, and the mounting plate 1, respectively. Therefore, in the conventional configuration, the housing 3 is molded by zinc die casting or aluminum die casting, and is machined by cutting or the like to increase the dimensional accuracy, which causes a high cost associated with the manufacture of the motor. In addition, this molding method is difficult to reduce the wall thickness, and cannot be made compact.

In view of the above problems, it is an object of the present invention to provide a motor which can be manufactured at a lower cost than conventional ones and which can be miniaturized.

[0009]

In order to achieve the above object, according to the present invention, a housing having a substantially cylindrical shape, a sleeve bearing attached to the inner peripheral surface of the housing, and the housing via the sleeve bearing are provided. A shaft rotatably supported on the rotor, a rotor having a rotor magnet and fixed to one end of the shaft, and an external fitting member fixed to the outer circumferential surface of the housing facing the rotor magnet by adhesion or press fitting. In a motor provided with a stator, the housing is formed by plastic working of a metal plate, and an outer stepped portion that comes into contact with the stator and positions the stator in the axial direction is provided on the outer peripheral surface of the housing. A mounting portion for mounting to the housing is provided at one end of the housing.

Further, the mounting portion extends from one end of the housing and is bent in a radial direction so as to abut on a part of the applied device or a mounting plate attached to the applied device for axial positioning. And a hanging part that extends from one end of the flange-shaped part and is bent in the radial direction to position the housing in the radial direction with respect to the applied device. .

Further, the bearing inner peripheral surface has a sliding surface with the shaft at both axial end portions except the axial central portion, and the bearing outer peripheral surface corresponding to the axial central portion is inside the housing. It is characterized in that it is fitted and fixed to the peripheral surface.

In addition, it has a substantially cylindrical housing, a ball bearing attached to the inner peripheral surface of the housing, a shaft rotatably supported by the housing via the ball bearing, and a rotor magnet. In a motor including a rotor fixed to one end of the shaft and a stator facing the rotor magnet and externally fixed to the outer peripheral surface of the housing by adhesion or press-fitting, the housing is formed by plastic working of sheet metal. The above-mentioned bearing is brought into contact with a protrusion formed by making a cut around the circumference of the cylindrical portion and projecting the vicinity of the cut inward in the radial direction for positioning in the axial direction. Is characterized by.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. For convenience of explanation, parts having the same functions as those of the conventional example are designated by the same reference numerals. FIG. 1 is a diagram showing a configuration of a motor according to an embodiment of the present invention. FIG. 1 (a) is a front vertical sectional view and FIG. 1 (b).
Is a bottom view. Here, an example of a brushless motor is shown as in the conventional example. In the figure, reference numeral 1 is a mounting plate which serves as a base for mounting at a required place in an applicable device such as the copying machine. FIG. 4 is an external perspective view schematically showing the housing (described later) of FIG.

A substantially cylindrical housing 3 formed by plastically working a sheet metal has its lower end bent radially outward at a plurality of peripheral locations (three locations at equal intervals in the circumferential direction in this embodiment). The brim-shaped portion 3a thus formed and a plurality of peripheral portions from the lower end portion (in this embodiment, 3 at equal intervals in the circumferential direction).
(Positioned in the middle of the collar-shaped portions 3a adjacent to each other at each position). This constitutes the motor side mounting portion. Further, an outer step portion 3c formed by drawing is provided on the outer peripheral surface, and the outer diameter of the upper portion is smaller than that of the lower portion with the outer step portion 3c as a boundary. Further, the inner peripheral surface is provided with an inner step portion 3c similarly formed by drawing, and the inner diameter is smaller at the upper side than at the lower side with the inner step portion 3c as a boundary.

A screw hole 3aa is formed in the collar-shaped portion 3a, and by screwing the screw hole 3aa in accordance with the hole 1a formed in the mounting plate 1, the shaft of the housing 3 is attached to the mounting plate 1. It is installed with directional positioning. At this time, the hanging portion 3b penetrates the mounting hole 2 formed inwardly of the mounting plate 1 so as to be surrounded by the hole 1a of the mounting plate 1 and abuts on the inner peripheral surface of the mounting hole 2 to perform radial positioning.

If the hole diameter of the mounting hole 2 is larger than the overall outer diameter of the plurality of hanging parts 3b, the hanging part 3b may be bent outward in accordance with this, and conversely, the mounting hole 2 may be bent. When the hole diameter is small, the hanging part 3b may be bent inward in accordance with this. Similarly, in the collar-shaped portion 3a, the length of the collar-shaped portion 3a may be changed according to the change in the diameter of the mounting hole 2. Thus, the hanging part 3b and the collar-shaped part 3a
Since it is formed by plastic working, it is possible to flexibly cope with various changes in the shape of the mounting plate 1 as compared with conventional die casting.

A sleeve bearing 7 made of a substantially cylindrical oil-impregnated metal is provided in a small inner diameter portion located above the inner step portion 3d.
Is press-fitted into the sleeve bearing 7
And a minute gap is formed, through which the shaft 9 is rotatably supported. A cup-shaped rotor 10 is provided on the upper end of the shaft 9 extending from the upper end of the housing 3.
Are fixed by press fitting or the like, and the rotor 10 rotates integrally with the shaft 9. An annular rotor magnet 11 is fitted and fixed to the inner peripheral surface of the outer peripheral wall of the rotor 10.

On the other hand, a stator core 13 is placed on the outer stepped portion 3c, and a stator coil 14 is wound around the stator core 13 at a small outer diameter portion located above the outer stepped portion 3c. However, they are externally fitted and fixed to the rotor magnet 11 by adhering or press fitting so as to face each other with a slight gap. The upper surface of the sleeve bearing 7 is held in sliding contact with the rotating rotor 10. Further, the lower surface of the sleeve bearing 7 is supported by the shaft 9 via the sliding ring 22, the washer 23, and the stopper ring 24.

Further, the tongue piece 1 is provided at four locations around the mounting plate 1.
b is provided, and the circuit board 20 is fixed to the mounting plate 1 with the screw 6 in the screw hole 1ba opened therein. The circuit board 20 is one in which required electronic components are mounted and a rotation drive circuit for the rotor 10 and a coil current control circuit for the stator 12 are formed. In addition, tongue pieces 1c are provided at the four corners of the mounting plate 1, and the mounting plate 1 is mounted on the applied device side through holes 1ca formed therein. It should be noted that the mounting plate 1 is provided in order to facilitate mounting of the motor to the applied device, but instead of providing a plate independent of the applied device like the mounting plate 1, one of the chassis forming the applied device is used. Alternatively, the portion may be used as a mounting portion and the motor may be directly mounted on the applicable device without using the mounting plate 1.

Screw teeth 21 are integrally formed on the lower end of the shaft 9 extending from the housing 3. When the brushless motor is attached to the applied device, a transmission gear (not shown) such as a reduction mechanism of the applied device is meshed with and connected to the screw teeth 21. The brushless motor is generated between the stator 12 and the rotor magnet 11 by supplying a drive current (excitation current) to the stator coil 14 of the stator 12 from the external drive power source via the control circuit of the circuit board 20. The rotor 10 is attracted by the magnetic attraction and repulsive force.
A rotational force is generated in the shaft 10, and the rotational force of the rotor 10
It is transmitted to the rotational drive load of the applied device through the screw teeth 21 and the transmission gear of the.

As described above, in this embodiment, the housing 3 is formed by the plastic working of the sheet metal, so that the material cost is low and the working time is low as compared with the conventional die casting. Can be shortened, and further, it is possible to reduce costs by being able to easily cope with various shape changes, and it is possible to reduce the wall thickness. Further, since the stator 12 is externally fitted and fixed to the housing 3 by adhesion or press-fitting, the conventional screw and screw hole are not required, so that the thickness of the housing 3 can be reduced.

As a result, the outer diameter of the housing 3 can be made smaller than in the conventional case, so that the inner diameter of the stator 12 can be made smaller. To that extent, the stator core 1 of the stator 12
3 can be increased or the winding amount of the stator coil 14 can be increased (improvement of the wire area ratio). Therefore, if the motor size is the same, a stronger output can be obtained,
Magnetic properties are improved compared to conventional ones. Alternatively, the stator 1
Although the 2 and the rotor magnet 11 have almost the same magnetic characteristics as the conventional one, the motor can be downsized accordingly.

Further, as shown in FIG. 1A, the sleeve bearing 7 has sliding surfaces 7 on the upper and lower portions of the inner peripheral surface, respectively.
a and 7b. These are surfaces that slightly project inward in the radial direction as compared with the central portion, that is, the inner diameter is small, and this surface slides on the shaft 9. A taper portion t is provided on the outer peripheral surface of the sleeve bearing 7 so as to decrease in diameter toward the upper end. When such a sleeve bearing 7 is press-fitted from the inner step portion 3d of the housing 3 to the upper small diameter portion as described above, the tightening margin is only in the central portion and does not come to the upper and lower portions. The moving surfaces 7a and 7b are not deformed by an extra force applied by press fitting.

Next, another embodiment of the present invention will be described. The motor of the present embodiment is a substantially cylindrical housing formed by plastically working a sheet metal, such as the housing 3 that constitutes the motor of the previous embodiment.
By making a notch in the periphery and plastically deforming the vicinity, and projecting inward in the radial direction, the bearing is positioned in the axial direction. By forming a notch in the circumferential direction of the housing, such a projecting portion serves as a bearing contact surface that is perpendicular to the axial direction, and can be formed with high accuracy.

A combination of ball bearings is suitable for a housing having such a protrusion. This is because the ball bearing needs to be preloaded in order to improve the bearing characteristics, and the mounting position must be set with high accuracy. It is desirable that three or more protrusions are provided at equal intervals in the circumferential direction of the housing with respect to one bearing. A specific configuration of such a protrusion provided on the housing is shown below.

FIG. 2 is a perspective view showing various configurations of the protruding portion provided on the housing. In the figure, since a plurality of protrusions of the same shape are provided at equal intervals in the circumferential direction, only one of them is shown and the inner peripheral surface of the housing is partially shown. The arrow direction is the axial direction and the vertical direction. The protrusion p shown in FIG.
It is formed by providing one cut 3e in the circumferential direction of the housing 3 and pushing the lower side (or the upper side) inward in the radial direction. At this time, the projection p has a substantially triangular shape when viewed in the axial direction. Then, the notch side of the protruding portion p becomes the substantially triangular bearing contact surface 3f, which can be used for positioning the bearing.

The protruding portion p shown in FIG. 3B is formed by providing a pair of upper and lower cuts 3e in the circumferential direction of the housing 3 and pressing the space between them inward in the radial direction. At this time, the projection p has a rectangular shape when viewed in the axial direction. Further, the bearing contact surface 3f having a rectangular shape at both upper and lower ends, which are cutout sides of the protrusion p, is rectangular.
Therefore, this can be used for positioning the bearing. The protrusion p may have a semicircular shape when viewed in the axial direction.

The protrusion p shown in FIG. 3 (c) is provided with a pair of upper and lower cuts 3e in the circumferential direction of the housing 3, and further has a cut 3g in the axial direction so as to connect both cuts, and is substantially surrounded by each cut. It is formed by pushing the broken portion inward in the radial direction. Here, the notch 3 of the protrusion p
Both the upper and lower ends on the e side serve as rectangular bearing contact surfaces 3f, which can be used for positioning the bearing. In this case, since the tip of the protruding portion p is a free end, the pulling force applied to the root portion of the protruding portion p is relaxed as compared with the cases of (a) and (b), so that in the housing 3 Strain does not easily occur, and it can be projected more inward in the radial direction.

When the protrusions shown in (a) to (c) above are used for positioning the bearings, when the bearings are a pair of upper and lower bearings, the protrusions may be provided for each bearing.
Further, in the case of using the protrusion of (b) or (c), the bearing contact surfaces at the upper and lower ends of one protrusion can be used for each bearing. Further, even when there is a pair of upper and lower bearings, the protrusions as shown in (a) to (c) above may be provided for positioning on only one of the bearings.

It is possible to provide the above-mentioned protrusions in the process of processing the housing, and since it is not necessary to additionally provide a positioning component, it is possible to further reduce the cost. In addition, in order to mount the motor having the housing having such a protruding portion on the applied device, it goes without saying that the motor side mounting portion as described in FIG. 1 may be provided.

[0031]

As described above, according to the present invention,
It can be manufactured at lower cost than before,
It is possible to provide a motor that has improved magnetic characteristics or has been downsized.

Further, with a simple structure, it is possible to provide a motor having a housing capable of accurately positioning the bearing in the axial direction.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a motor according to an embodiment of the present invention.

FIG. 2 is a perspective view showing various configurations of a protrusion provided on a housing of a motor according to another embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a conventional brushless motor.

FIG. 4 is an external perspective view schematically showing the housing of FIG.

[Explanation of symbols]

1 Mounting plate 2 mounting holes 3 housing 3a Collar part 3b hanging part 3c outer step 3d inner step 5,6 screws 7 Sleeve bearing 9 shaft 10 rotor 11 rotor magnet 12 stator 13 Stator core 14 Stator coil 20 circuit board 21 screw teeth 22 Sliding ring 23 washer 24 Stopper ring

Claims (4)

[Claims] 1. A housing having a substantially cylindrical housing, a sleeve bearing mounted on an inner peripheral surface of the housing, a shaft rotatably supported by the housing via the sleeve bearing, and a rotor magnet. In a motor including a rotor fixed to one end of the shaft, and a stator facing the rotor magnet and externally fitted and fixed to an outer peripheral surface of the housing by adhesion or press-fitting, the housing is formed by sheet metal working. The outer stepped portion that comes into contact with the stator and positions the stator in the axial direction is provided on the outer peripheral surface of the housing, and the attachment portion for attaching to the applicable device on which the motor is mounted is provided at one end of the housing. Characteristic motor. 2. The mounting portion extends from one end of the housing and is bent in a radial direction so as to come into contact with a part of the applied device or a mounting plate attached to the applied device for axial positioning. And a hanging portion that extends from the one end and is bent in the radial direction to position the housing in the radial direction with respect to the applied device. Claim 1
The motor described in. 3. The bearing inner peripheral surface has sliding surfaces with the shaft at both axial end portions except the axial central portion, and the bearing outer peripheral surface corresponding to the axial central portion is inside the housing. 2. The device is fitted and fixed to the peripheral surface.
Alternatively, the motor according to claim 2. 4. A substantially cylindrical housing, a ball bearing mounted on the inner peripheral surface of the housing, and a shaft rotatably supported by the housing via the ball bearing.
A motor comprising: a rotor having a rotor magnet fixed to one end of the shaft; and a stator facing the rotor magnet and externally fixed to the outer peripheral surface of the housing by adhesion or press fitting. Is a substantially cylindrical shape formed by plastic working of a sheet metal, and the bearing is brought into contact with a protruding portion in which a notch is formed around the cylindrical portion and a portion in the vicinity of the notch is protruded inward in the radial direction. A motor characterized by directional positioning.