JPH10295070A - Motor and motor assembly method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and surely align a stator and a rotor supporting member with each other by a simple construction, when a motor is assembled and improve the various characteristics of the motor. SOLUTION: A stepper motor 1 is composed of a stator 2, a rotor 6 which is inserted rotatably into the inside of the stator 1, a bottom plate 7 and an attaching plate 8 which are fixed to both the ends of the stator 2 and bearings 9a and 9b which are fixed to the attaching plate 8 and the bottom plate 7 respectively. The stator 2 is composed of a pair of inner yokes 3 and a pair of outer yokes 4 and a pair of coils 5 provided between the yokes. The inner yokes 3, the outer yokes 4 and the coils 5 are fixed to each other, so as to have the base parts 31 of both the inner yokes 3 bonded to each other. A positioning recess 47 is formed in the outer yoke 4 on a base end side, and a protrusion 72 which is retained with the recess 47 is formed on the bottom plate 7. Outer circumferential edge parts 32 of the base parts 31 of the inner yokes 3 are exposed near the outer circumferential surfaces of the outer yokes 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a motor and a method for assembling the motor.

[0002]

2. Description of the Related Art A small stepping motor is used for driving a lens for focusing and zooming of a camera or a video camera. This stepping motor is required to have low power consumption, obtain a predetermined torque required for driving the lens with the lowest possible input value (current), and increase the speed of driving the lens, for reasons related to its use. Characteristics such as being able to rotate to a high frequency range and good angle accuracy are required.

FIGS. 18 and 19 show the structure of a conventional stepping motor. The conventional stepping motor 100 shown in these figures includes a stator 120 and the stator 12.
The rotor 160 includes a rotor 160 rotatably inserted into the inside of the stator 120, a bottom plate (cover) 181 fixed to both end surfaces of the stator 120, and a mounting plate 182. Bearings 191 and 192 for supporting the rotating shaft 161 of the rotor 160 are fixed to the bottom plate 181 and the mounting plate 182, respectively.

[0004] The stator 120 includes a set of inner yokes 130,
Outer yokes 140 and coil 1 installed between them
Two sets of 50 are prepared, and they are attached to the base 13 of the inner yoke 130.
1 are fixedly bonded to each other.

A plurality of magnetic poles 134 and 144 are formed on the inner yoke 130 and the outer yoke 140, respectively.
The magnetic poles 134 and 144 of the yokes 130 and 140 are fixed to the cylindrical permanent magnet 1 fixed to the rotation shaft 161 of the rotor 160.
62 are arranged alternately along the outer peripheral surface of the outer surface 62 and in a non-contact manner with each other. Further, the inner yoke 130 and the outer yoke 14
Each of the 0 magnetic poles faces the outer peripheral surface of the permanent magnet 162 of the rotor 160 with a predetermined gap (gap) 170 therebetween.

[0006] Such a conventional stepping motor 10
In the 0 stator 120, the inner yoke 130 and the outer yoke 140 can be positioned by their own shapes.

That is, as shown in FIG. 19, the end of the outer yoke 140 (the contact surface 13 between the inner yokes 130)
9), a step 145 is formed inside the inner yoke 1.
The outer peripheral edge 132 of the base 131 of this 30
, The inner yoke 130 is fitted to the outer yoke 140, and the two yokes 130, 140 are aligned.
Therefore, as shown in FIG.
The outer peripheral portion 131 of the inner yoke 130 is not exposed in the vicinity of the contact surface 139 of the outer peripheral surface of the inner yoke 130.

Further, when assembling the stepping motor 100, the stator 120, the bottom plate 181 and the mounting plate 1
82, that is, the radial alignment between the outer yoke 140 and the bottom plate 181 and the outer yoke 140
And the mounting plate 182 in the radial direction, respectively.
This was performed by a jig (not shown) having a center pin composed of a positioning column having an outer diameter equal to the inner diameter of the bearings 191 and 192, and a positioning column having an outer diameter equal to the inner diameter of the outer yoke 140. .

However, in such a structure, as described above, the outer yoke 140 and the bottom plate 1 are assembled when the motor is assembled.
81, and the outer yoke 140 and the mounting plate 182 need to be aligned with a jig, respectively, so that it takes time and effort to assemble the motor, and it takes a long time to assemble the motor.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to easily and surely position a stator (yoke) and a rotor support member at the time of assembly with a simple structure. It is an object of the present invention to provide a motor whose characteristics can be improved and a method of assembling such a motor that can be easily assembled.

[0011]

This and other objects are achieved by the present invention which is defined below as (1) to (14).

(1) A stator having a yoke and a coil, a rotor rotatably inserted inside the stator, and a rotor support member installed on an end face of the stator and supporting the rotor. And a positioning means for positioning the yoke and the rotor support member.

(2) A stator having at least one set of an inner yoke, an outer yoke and a coil disposed therebetween, a rotor rotatably inserted inside the stator, A plurality of magnetic poles formed on the inner yoke and a plurality of magnetic poles formed on the outer yoke, the rotor having a rotor support member installed on an end face and supporting the rotor; In the motor alternately arranged along the surface, the outer yoke and the rotor support member,
A motor provided with positioning means for performing these positioning.

(3) A stator having two sets of an inner yoke, an outer yoke, and a coil disposed therebetween, and a stator in which the inner yokes are joined to each other, and rotatably inserted inside the stator. Rotor, and a rotor support member installed on both end faces of the stator and supporting the rotor, a plurality of magnetic poles formed on the inner yoke, and formed on the outer yoke. In a motor in which a plurality of magnetic poles are alternately arranged along the outer peripheral surface of the rotor, at least one of the two sets of the outer yoke and the rotor support member positions the outer yoke and the lid member. A motor provided with positioning means for performing the following.

(4) The motor according to (2) or (3), wherein the inner yoke has a plate-shaped base, and an outer edge of the base is exposed near an outer surface of the outer yoke. .

(5) The inner yoke has a disk-shaped base having an outer diameter substantially equal to the outer diameter of the outer yoke, and an outer peripheral edge of the base is exposed near an outer peripheral surface of the outer yoke. The motor according to (2) or (3) above.

(6) The magnetic poles of the inner yoke and the outer yoke are not in contact with the outer peripheral surface of the rotor, and are installed at positions equidistant from the rotation center of the rotor. The motor according to any one of (5).

(7) The motor according to any one of (1) to (6), wherein the positioning means is configured to perform at least center axis alignment of the stator and the rotor support member.

(8) The motor according to any one of the above (1) to (7), wherein the positioning means is a concave and a convex engaged with each other.

(9) The motor according to the above (8), wherein the height of the projection is 20 to 80% of the thickness of the rotor support member.

(10) The above-mentioned (8) or (9), wherein a plurality of the protrusions are provided along a rotation direction of the rotor.
A motor according to claim 1.

(11) The motor according to any one of (8) to (10), wherein the concave portion and the convex portion are formed at the same time when the member on which these are formed is press-molded.

(12) The motor according to any one of the above (1) to (11), wherein the outer diameter of the rotor is 1 to 30 mm.

(13) A method for assembling a motor according to any one of the above (4) to (6), wherein a coil is inserted between an inner yoke and an outer yoke, and the inner yoke and the outer A first step of assembling the stator by combining these parts while performing alignment with the yoke, inserting the rotor inside the stator, and performing alignment between the rotor support member and the outer yoke. And a second step of coupling the rotor support member and the outer yoke.
The positioning of the inner yoke and the outer yoke in the step is performed based on the inner diameter of the stator, and the positioning of the outer yoke and the rotor supporting member in the second step is performed by the positioning. A method for assembling a motor, the method being performed by means.

(14) The motor assembling method according to (13), wherein the positioning of the inner yoke and the outer yoke is performed by inserting a jig into a bore of the stator.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a motor and a method for assembling the motor according to the present invention will be described in detail with reference to the preferred embodiments shown in the accompanying drawings.

FIG. 1 is a plan view showing an embodiment in which the motor of the present invention is applied to a stepping motor, FIG. 2 is a sectional view taken along line AA in FIG. 1, and FIG. FIG. 4 is a plan view showing the configuration, FIG. 4 is a bottom view showing the configuration of the outer yoke,
FIG. 5 is an exploded perspective view showing the configuration of the inner yoke and the outer yoke, FIG. 6 is a plan view showing the configuration of the outer yoke, FIG. 7 is a sectional view taken along line BB (end view) in FIG. 8 is a plan view showing the configuration of the inner yoke, and FIG. 9 is a sectional view (end view) taken along the line CC in FIG. In the following description, the upper side in FIGS. 1 and 2 is referred to as a “base end”, and the lower side is referred to as a “distal end”.

As shown in FIGS. 1 and 2, the stepping motor 1 of the present embodiment is a PM type stepping motor, and is mainly provided with a stator 2 and a rotatable inside of the stator 2. Rotor 6 and base end (end face) of stator 2
A bottom plate (cover) 7 fixed to the base plate, a mounting plate 8 fixed to the front end (end face) of the stator 2, a bearing 9a fixed to the mounting plate 8, and a bearing 9b fixed to the bottom plate 7. Have been.

As shown in FIGS. 2 to 4, the stepping motor 1 has a positioning means composed of a convex portion 72 formed on the bottom plate 7 and a concave portion 47 formed on the outer yoke 4. I have. The positioning means will be described later in detail.

As shown in FIGS. 1 and 2, the stator 2
Is a unit composed of one set of the inner yoke 3, the outer yoke 4, and the coil 5 provided therebetween, that is, a unit composed of the inner yoke 3, the outer yoke 4, and the coil 5. And a unit composed of the inner yoke 3 ′, the outer yoke 4 ′ and the coil 5, which are fixed so that the bases 31, 31 ′ of the inner yokes 3, 3 ′ are joined to each other. It becomes. Both unit bodies are provided with concave portions 47 described later.
Since they have almost the same structure except for the presence or absence of, one unit (base end side) will be representatively described below.

As shown in FIGS. 2 and 4 to 7, the outer yoke 4 is a bottomed cylindrical member made of a soft magnetic material, and has a bottom 41, and a cylinder erected from the bottom 41. And a plurality of magnetic poles 44 erected from the edge of an opening 43 formed in the center of the bottom 41 in the same direction as the outer periphery 42.

Notches 45 and 46 are formed in the outer peripheral portion 42 at positions facing each other via the opening 43. A terminal portion 53 formed on a bobbin 51, which will be described later, is inserted into the notch 45 so as to protrude outward.
6 is fitted with positioning projections 54 formed on the bobbin 51, thereby positioning the bobbin 51 with respect to the outer yoke 4.

In this embodiment, the number of the magnetic poles 44 is five, and each magnetic pole 44 is located at the center of rotation (the axis 60) of the rotor 6.
From each other, that is, at equal angular intervals on concentric circles. Further, the width of each magnetic pole 44 gradually decreases in a direction away from the bottom 41 (upward in FIG. 5).

A magnetic pole 34 of the inner yoke 3 described later is inserted between the adjacent magnetic poles 44 in a non-contact manner. In this case, the magnetic pole 34 and the magnetic pole 44 face in opposite directions.

As shown in FIGS. 2, 5, 8 and 9, the inner yoke 3 is a member made of a soft magnetic material, and has a disk-shaped (annular plate-shaped) base 31 and a base 31. It comprises a plurality of magnetic poles 34 erected from the edge of an opening 33 formed at the center of 31.

The outer diameter of the base 31 is substantially the same as the outer diameter of the outer yoke 4 (more specifically, the outer diameter near the end 421 of the outer peripheral portion 42).

Notches 35 and 36 are formed in the outer peripheral portion of the base 31 at positions facing each other via the opening 33. A terminal portion 53 formed on the bobbin 51 is inserted into the notch 35 and protrudes outward.
Are fitted with positioning protrusions 54 formed on the bobbin 51, and thereby the bobbin 51 is positioned with respect to the inner yoke 3.

A protrusion 37 and a hole 38 are formed in the base 31 at positions facing each other via the opening 33. The protrusion 37 and the hole 38 are respectively provided in FIG.
It fits with the hole 38 'and the protrusion 37' of the other inner yoke 3 'shown by the middle dotted line, and positions the inner yokes 3, 3' in the rotational direction (circumferential direction), that is, in the rotational direction of the unit bodies. This is for positioning.

In this embodiment, the number of the magnetic poles 34 is five, the same as the number of the magnetic poles 44, and each magnetic pole 34 is equidistant from the axis 60, that is, equiangular on the concentric circle similarly to the magnetic pole 44. They are arranged at intervals. Further, the width of each magnetic pole 34 gradually decreases in a direction away from the base 31 (downward in FIG. 5).

Such an inner yoke 3 and an outer yoke 4
Are different from the inner yoke 130 and the outer yoke 140 of the conventional stepping motor 100 in that they do not have a means (step portion 145) for aligning the inner yoke 3 and the outer yoke 4. . Therefore, when assembling the stator 2, the inner yoke 3 and the outer yoke 4 are aligned using, for example, a jig 23 described later, and these are combined.

In a state where the outer yoke 4 and the inner yoke 3 are combined, the five magnetic poles 44 and the five magnetic poles 34 are arranged alternately on concentric circles and are not in contact with each other.
A total of 10 magnetic poles are formed. Also, in this state,
The base 31 of the inner yoke 3 abuts on the end 421 of the outer peripheral portion 42, and the outer peripheral edge 32 of the base 31 is exposed near the outer peripheral surface of the outer yoke 4.

As described above, in the present invention, since the outer peripheral edge portion 32 of the base portion 31 does not abut on the outer peripheral portion 42, the outer diameter of the base portion 31 and the outer diameter of the outer peripheral portion 42 near the end portion 421 are temporarily reduced. Even if there is a dimensional error, the dimensional error is
It is only absorbed as a deviation between the outer peripheral surface of the outer peripheral portion 42 and the vicinity of the end 421 of the outer peripheral portion 42, and does not affect the positional relationship between the magnetic pole 34 and the magnetic pole 44 inside the stator 2. Therefore, the dimensional accuracy of the gap 15 is extremely high.

When the outer yoke 4 and the inner yoke 3 are combined, the coil 5 is inserted into an annular space formed between the outer peripheral portion 42 and the magnetic poles 34, 44. The coil 5 is obtained by applying a winding 52 to a bobbin 51 made of an insulating material such as a synthetic resin. The terminal portion 53 formed on the bobbin 51 is formed by burying a pair of terminals 531 and 532 in the constituent material (synthetic resin) of the bobbin 51 in a non-contact manner. And winding 5
Both ends of 2 are electrically connected to terminals 531 and 532 of the terminal section 53, respectively.

The drive circuit (not shown) of the stepping motor 1 allows the winding 52 to be connected through these terminals 531 and 532.
When a pulse signal is supplied to the coil 5, the coil 5 is excited, and a torque for driving the rotor 6 to rotate is generated. Then, the rotor 6 rotates a predetermined number of steps, that is, a predetermined angle, according to the number of pulses of the input pulse signal.

The unit as described above is composed of the inner yokes 3, 3 '
Are fixed by, for example, welding so that the base portions 31 and 31 ′ are joined to each other. It is preferable that the abutting surfaces 39 of the bases 31 and 31 'are joined as closely as possible, that is, in close contact.

In this case, the two unit bodies are fixed in a positional relationship such that the magnetic poles 34 and 44 in one unit body and the magnetic poles in the other unit body are shifted by a half pole in the circumferential direction. Therefore, the protrusion 37 and the hole 38 and the hole 38 'and the protrusion 37' are formed at such positions that both units have such a positional relationship. With such a configuration, the number of steps of the stepping motor 1 is 20 steps in total. Note that the microstep driving may be further performed by the driving circuit of the stepping motor 1.

In the present invention, it goes without saying that the number of magnetic poles and the number of steps are not limited to those described in this embodiment.

As shown in FIG. 2, the rotor 6 includes a rotating shaft 6
1 and a cylindrical permanent magnet 62 installed on the outer periphery of the rotating shaft 61. In this case, the rotating shaft 61 and the permanent magnet 62
1 is press-fitted, or the rotating shaft 61 is inserted (fitted) into the inner cavity of the permanent magnet 62, and these are fixed by bonding with an adhesive.

The permanent magnet 62 is multipolarly magnetized (10 poles) in the radial direction. In addition, as the permanent magnet 62,
Magnets having excellent magnetic properties are used. For example, a rare earth magnet containing a rare earth element and a transition metal as basic components or a rare earth magnet containing a rare earth element, a transition metal and boron as basic components are suitably used. Further, the form (type) of the permanent magnet 62 may be any type such as a bonded magnet or a sintered magnet.

When the rotor 6 is inserted into the inner cavity (inner hole) of the stator 2, the magnetic poles 34 and 44 face the outer peripheral surface of the permanent magnet 62 without contact. In this case, the distance between the outer peripheral surface of the permanent magnet 62 and each of the magnetic poles 34 and 44 is preferably about 0.05 to 0.25 mm, more preferably about 0.10 mm.
A gap (gap) 15 of about 0.20 mm is formed.

A bottom plate (cover) 7 is fixed to the base end of the stator 2, that is, the bottom 41 of the outer yoke 4 on the base end side. This fixing is preferably performed by welding such as plasma welding.

A circular opening 71 is formed in the bottom plate 7, and the bearing 9b is press-fitted into the circular opening 71.

As shown in FIGS. 2 and 3, a positioning convex portion 72 for engaging with a concave portion 47 described later is formed on the distal end side of the bottom plate 7. The five protrusions 72 are formed at equal intervals (equal angle intervals) along the rotation direction (circumferential direction) of the rotor 6.

The height h ₁ of the projection 72 is equal to the thickness h _{2 of the} bottom plate 7.
Is preferably about 20 to 80%, more preferably about 40 to 80%.

When the height h ₁ of the convex portion 72 exceeds 80% of the thickness h ₂ of the bottom plate 7, the strength of the convex portion 72 is remarkably reduced, and there is a possibility that cracks or falling off may occur.
Depending on various conditions such as the size and material of the motor, the concave portion 47 and the convex portion 72 may be disengaged during the assembly of the motor, and may be joined with the concave portion 47, thus causing a defect.

The cross-sectional shape of the projection 72 is rectangular in the present embodiment, but is not limited to the illustrated shape in the present invention, and may be, for example, a trapezoid, a triangle, a semicircle, a semiellipse, or the like. There may be.

As shown in FIGS. 2 and 4, the outer yoke 4
In the bottom 41, five concave portions 47 for positioning corresponding to the convex portions 72 are formed.

The shape, arrangement (pattern),
Conditions such as dimensions are such that when the recess 47 engages with the corresponding protrusion 72, the center axes of the outer yoke 4 and the bottom plate 7 match, that is, the center axes of the outer yoke 4 and the bearing 9b match. Is set to

In other words, in this stepping motor 1, the engagement between the concave portion 47 and the convex portion 72 allows
The outer yoke 4 and the bottom plate 7 are aligned in the radial direction. In addition to the radial alignment, the outer yoke 4 and the bottom plate 7 are also aligned in the rotational direction.

The concave portion 47 and the convex portion 72 are preferably formed at the same time as the members on which they are formed, that is, when the outer yoke 4 and the bottom plate 7 are pressed. Thereby, the concave portions 47 and the convex portions 72 can be formed without increasing the number of manufacturing steps of the stepping motor 1.

In the present invention, the concave portion 47 and the convex portion 7 are provided.
Various conditions such as the number, arrangement (pattern), dimensions, and the like of 2 are not limited to those shown in the drawings as long as the position of the outer yoke 4 and the bottom plate 7 can be adjusted by the concave portions 47 and the convex portions 72.

As shown in FIG. 2, a mounting plate 8 is fixed to the front end of the stator 2, that is, to the bottom 41 of the outer yoke 4 'on the front end side. This fixing is preferably performed by welding such as plasma welding.

The mounting plate 8 has a circular opening 81 formed therein.
The bearing 9a is press-fitted into the circular opening 81.

The constituent materials of the bottom plate 7 and the mounting plate 8 include, for example, various metal materials, resins, ceramics and the like.

The rotating shaft 61 of the rotor 6 is rotatably supported by the bearings 9a and 9b described above. Therefore, the bottom plate 7 and the bearing 9b constitute a rotor support member for supporting the base end side of the rotor 6, and the mounting plate 8 and the bearing 9a constitute a rotor support member for supporting the distal end side of the rotor 6. Is done.

In this embodiment, the bearings 9a, 9
For b, a sliding bearing made of a sintered body is used, but a sliding bearing or a rolling bearing (bearing) formed by resin molding may be used.

A gear, a worm, a pulley, or the like can be provided at the tip (long axis side) of the rotating shaft 61, for example.

The inner yoke 3 and the outer yoke 4 are made of a soft magnetic material such as pure iron, a galvanized steel sheet, Fe--C
It may be made of a metal material such as an r alloy.

Here, for a small stepping motor having an outer diameter of the rotor 6 of about 1 to 30 mm, especially about 4 to 8 mm, for example, low power consumption is required for reasons related to its use. Although required characteristics are required such that a required predetermined torque can be obtained with an input value (current) as low as possible, rotation can be performed up to a high frequency range for high-speed driving, and angular accuracy is good. In the stepping motor 1, these characteristics can be sufficiently satisfied.

Next, an example of an assembling method of the stepping motor 1 will be described.

FIGS. 10, 11 and 12 are sectional side views showing the steps of an embodiment of the method for assembling a motor according to the present invention.

As shown in these figures, this assembling method involves positioning the inner yoke 3 and the outer yoke 4 and positioning the inner yoke 3 'and the outer yoke 4' with the inner diameter of the stator 2 ( This method is performed based on the inner diameter of the inner cavity of the stator 2).

More specifically, a jig 21 having a center pin (center pin with a dowel) 22 composed of positioning cylinder portions 221 and 222 shown in FIG. 10 and a center pin (positioning pin) shown in FIG. A jig 23 having a cylindrical portion 24 is prepared, and the outer yoke 4 'on the distal end side is inserted into the positioning cylindrical portion 221 of the jig 21, as shown in FIG. The mounted mounting plate 8 is inserted into the positioning cylinder 222. As a result, the outer yoke 4 'and the bearing 9a are aligned in the radial direction based on the inner diameter.

Then, the boundary (the outer boundary) between the outer yoke 4 'and the mounting plate 8 is welded by, for example, plasma welding, and these are fixed (coupled).

Next, the coil 5 is assembled by winding the bobbin 51 on the bobbin 51, and the coil 5 is placed between the inner yoke 3 and the outer yoke 4 on the base end side, that is, the outer peripheral portion 42 and each magnetic pole 3.
4 and 44 are inserted into the annular space formed between them. At this time, the terminal portions 53 and the positioning projections 54 of the bobbin 51 are respectively inserted into the corresponding notches 35, 36, 45,
Insert at 46.

Then, as shown in FIG. 11, the unit on the base end side is inserted into the center pin 24 of the jig 23.

Next, the outer yoke 4 'on the distal end side to which the mounting plate 8 is fixed is removed from the jig 21, and the coil 5 is moved between the inner yoke 3' and the outer yoke 4 'in the same manner as described above.
That is, it is inserted into an annular space formed between the outer peripheral portion 42 and each of the magnetic poles 34 and 44, and the unit body on the distal end side is attached to the jig 2
No. 3 center pin 24.

At this time, the bases 31 and 31 ′ of the inner yokes 3 and 3 ′ of both unit bodies are positioned so that the projection 37 and the hole 38 ′ and the hole 38 and the projection 37 ′ are fitted. While joining. Thereby, the positioning of the inner yokes 3, 3 'in the rotational direction is performed.

When the center pin 24 of the jig 23 is inserted into the inner cavity of the stator 2, the outer peripheral edge 32 of the base 31, 31 ′ of the inner yoke 3, 3 ′ is Since it is exposed in the vicinity, the radial movement of the inner yokes 3, 3 'with respect to the outer yokes 4, 4' and the radial movement of the inner yoke 3 with respect to the inner yoke 3 'are possible. Therefore, the inner yokes 3, 3 'and the outer yokes 4 and 4' of both units are
Each of the magnetic poles 34, 44 is equidistant from the axis 60,
That is, positioning is performed so as to be arranged on concentric circles.

Then, a pressing force in the direction of the axis 60 is applied to the stator 2 to make the gap between the contact surfaces 39 as small as possible.
The boundary between the outer peripheral portion 42 of the outer yoke 4 and the outer peripheral portion 42 and the boundary between the base 31 ′ and the outer peripheral portion 42 of the outer yoke 4 ′ (the outer peripheral boundary) are respectively, for example, plasma-welded. To fix (bond) them. As described above, the first step of assembling the stator 2 is completed.

Next, the stator 2 is removed from the jig 23, and as shown in FIG. 12, the pre-assembled rotor 6 is inserted into the inner cavity of the stator 2 and the bearing 9b is fixed in advance. The bottom plate 7 is applied to the bottom 41 of the outer yoke 4 on the base end side, and the concave portion 47 of the outer yoke 4 and the convex portion 72 of the bottom plate 7 are engaged. As a result, the outer yoke 4 and the bottom plate 7 are aligned in the radial and rotational directions, and the center axes of the stator 2, the bearing 9a, and the bearing 9b coincide.

Then, the boundary (the outer boundary) between the outer yoke 4 and the bottom plate 7 is welded, for example, by plasma welding, and these are fixed (coupled). As described above, the second step is completed, and the stepping motor 1 is completed.

As described above, in the stepping motor 1, the outer peripheral edges 32 of the bases 31, 31 'of the inner yokes 3, 3' are exposed near the outer peripheral surfaces of the outer yokes 4, 4 '. The alignment between the inner yokes 3, 3 'and the outer yokes 4, 4' and the alignment between the inner yoke 3 and the inner yoke 3 'can be performed on the basis of the inner diameter.

The outer yoke 4 and the bottom plate 7 are formed with the concave and convex portions 47 and the protrusions 72 for positioning, so that the outer yoke 4 and the bottom plate 7 can be aligned without using a jig. In particular, they can be easily and reliably centered. In other words, a motor such as the stepping motor 1 in which the rotor supporting members are installed (fixed) on both end surfaces of the stator is assembled easily and efficiently while performing the positioning based on the inner diameter. Can be.

Thus, each of the magnetic poles 34, 4
The dimensional accuracy of the gap 15 between the rotor 4 and the rotor 6 is improved, and magnetic leakage is also prevented. Therefore, various characteristics of the stepping motor 1 are improved, and variations in motor performance are prevented. .

In particular, a predetermined torque can be obtained at a lower input value (current), thereby saving power consumption, prolonging the life of the battery, and enabling rotation to a higher frequency range. Speed can be increased, and the angle accuracy can be improved.

Further, the structure of the stepping motor 1 is simple, and the number of man-hours at the time of its manufacture (at the time of assembly) is relatively small, so that the productivity is good and it is advantageous for mass production. It is also suitable for automation of motor assembly.

Since the stepping motor 1 has relatively few welding points, it is easy to assemble and has a high yield.

Next, another embodiment of the motor of the present invention will be described.

FIGS. 13, 14 and 15 are sectional side views each showing an embodiment in which the motor of the present invention is applied to a stepping motor. In the following description, the upper side in FIGS. 13 to 15 is referred to as a “base end”, and the lower side is referred to as a “distal end”. The description of the common points with the stepping motor 1 shown in FIGS. 1 to 9 will be omitted, and the main differences will be described.

In the stepping motor 1 shown in FIG.
A convex portion 48 is formed on the outer yoke 4 on the base end side, and a concave portion 73 that engages with the convex portion 48 is formed on the bottom plate (cover) 7.

In the present invention, in addition to the above, a concave portion 47 and a convex portion 48 are formed in the outer yoke 4 on the base end side, and
Further, a convex portion 72 and a concave portion 73 that engage with the concave portion 47 and the convex portion 48 may be formed.

In the stepping motor 1 shown in FIG.
A concave portion 47 is formed in the outer yoke 4 ′ on the tip side, and the mounting plate 8 is formed.
A convex portion 82 that engages with the concave portion 47 is formed.

The assembling method of the stepping motor 1 is as follows.
Finally, the concave portion 47 of the outer yoke 4 'and the convex portion 82 of the mounting plate 8 are engaged, and the outer yoke 4' and the mounting plate 8 are fixed (joined) by, for example, plasma welding. )
I do.

In the present invention, even when the positioning means is provided between the outer yoke 4 'on the distal side and the mounting plate 8 as described above, the convex portion is formed on the outer yoke 4' on the distal side as described above. A concave portion may be formed on the mounting plate 8 to be engaged with the convex portion. Also, a concave portion and a convex portion may be formed on the outer yoke 4 ′ on the distal end side, and the mounting plate 8 may be associated with the concave portion and the convex portion. Convex and concave portions may be formed.

In the stepping motor 1 shown in FIG.
A concave portion 47 is formed in the outer yoke 4 on the base end side, a convex portion 72 engaging with the concave portion 47 is formed on the bottom plate 7, and a concave portion 47 is formed on the outer yoke 4 'on the distal end side. A convex portion 82 that engages with the concave portion 47 is formed.

The assembly of the stepping motor 1 is as follows.
For example, it can be performed as follows.

First, using the jig 23 shown in FIG. 11, the inner yokes 3, 3 'and the outer yokes 4, 4' based on the inner diameter are used.
Assemble the stator 2 while aligning the positions.

Next, the stator 2 is removed from the jig 23, the rotor 6 is inserted into the inner cavity of the stator 2, and the concave portion 47 of the outer yoke 4 and the convex portion 72 of the bottom plate 7 are engaged.
Further, the concave portion 47 of the outer yoke 4 ′ and the convex portion 82 of the mounting plate 8 are provided.
And the outer yoke 4 and the bottom plate 7, and the outer yoke 4 ′ and the mounting plate 8 are respectively fixed (coupled) by, for example, plasma welding.

In the present invention, the positioning means is provided for the outer yoke 4 and the bottom plate 7 on the proximal end side and the outer yoke 4 'and the mounting plate 8 on the distal end side.
Various combinations as described above are possible for each positioning means.

The same effects as those of the stepping motors 1 shown in FIGS. 1 to 9 can be obtained with the stepping motors 1 of the embodiments.

In particular, the stepping motor 1 shown in FIG.
Since the positioning means are provided on the outer yoke 4 and the bottom plate 7 on the proximal end and on the outer yoke 4 'and the mounting plate 8 on the distal end, the assembling of the stepping motor 1 can be performed more easily and in a shorter time. It can be carried out. Further, when assembling the stepping motor 1, the rotor 6 can be inserted into the lumen of the stator 2 from either the distal end side or the proximal end side, so that the degree of freedom in the assembly process is wide.

[0103]

【Example】

(Example) In order to confirm the effects of the motor (stepping motor) of the present invention as described above, the stepping motor 1 shown in FIGS. 1 to 9 was manufactured, and the relationship between the driving speed-torque of this stepping motor 1 and The relationship between the driving speed of the stepping motor 1 and the self-starting current was examined. These results are shown in the graphs of FIG. 16 and FIG.

The various conditions and measurement conditions for the stepping motor 1 are as follows.

[0105] outer diameter of the stator: 8 mm stator inner diameter: 4.3 mm (design value) stator height: outer diameter of 8.1mm rotor: 4 mm bottom plate of (cover) thickness h _2: 0. 4 mm Number of convex and concave portions: 5 each Height of convex portion h ₁ : 0.3 mm (75% of h ₂ ) Depth of concave portion: 0.4 mm Gap interval: 0.15 mm (design value) Spacing error: within ± 0.05mm Permanent magnet: Bond magnet made of Sm-Co magnetic powder and Nd-Fe-B compression molded isotropic magnet Number of magnetic poles: 10 poles x 2 (total 20 steps) Coil specifications: 9Ω Designated voltage: 3 V Driving method: Bipolar two-phase excitation (Comparative example) As a comparative example, a conventional stepping motor 100 shown in FIGS. 18 and 19 was manufactured, and the relationship between the driving speed and the torque of this stepping motor 100 and Drive speed of stepping motor 1 We examined the relationship of self-starting current. These results are shown in the graphs of FIG. 16 and FIG.

The various conditions and measurement conditions for the stepping motor 100 are as follows.

[0107] outer diameter of the stator: 8 mm stator inner diameter: 4.3 mm (design value) stator height: outer diameter of 8.1mm rotor: 4 mm bottom plate of (cover) thickness h _2: 0. 4mm Convex part and concave part: none Gap interval: 0.15mm (design value) Gap interval error: within ± 0.11mm Permanent magnet: Bond magnet and Nd-Fe-B compression molding using Sm-Co magnetic powder Isotropic magnet Number of magnetic poles: 10 poles x 2 pieces (total of 20 steps) Coil specification: 9Ω Designated voltage: 3V Driving method: Bipolar two-phase excitation As described above, the stepping motor of the present invention has a smaller gap than the comparative example. Is small and the dimensional accuracy is high.

As shown in FIG. 16, the stepping motor of the present invention has a higher pull-in torque and a higher pull-out torque in a high-speed range than the comparative example. In particular, the maximum self-starting frequency of the stepping motor of the comparative example is 760 pps.
On the other hand, the maximum self-starting frequency of the stepping motor of the present invention is about 960 pps, and the maximum self-starting frequency is improved. The maximum continuous response frequency of the stepping motor of the comparative example is about 2016 pps, whereas the maximum continuous response frequency of the stepping motor of the present invention is 2160 pps or more, and the maximum continuous response frequency is improved. I have.

Further, as shown in FIG. 17, the stepping motor of the present invention has a lower self-starting current (voltage) in a high-speed region than the comparative example. In particular, while the self-starting current of the stepping motor of the present invention at 500 pps is about 21 mA, the self-starting current of the stepping motor of the comparative example at the same frequency is 28 mA or more. It has been reduced by more than 25%.

Although the motor and the method of assembling the motor according to the present invention have been described based on the illustrated embodiments, the present invention is not limited to these embodiments. Can be appropriately replaced with any one that can produce the same function.

In each of the above embodiments, two sets of unit bodies are used as the stator 2 in order to improve the stability (balance) in the structure and the magnetic circuit.
One or three or more sets may be used.

In each of the above embodiments, the outer peripheral edge of the base of the inner yoke is exposed near the outer peripheral surface of the outer yoke.
In the present invention, the outer peripheral edge (outer edge) of the base of the inner yoke may not be exposed.

In each of the above embodiments, the protrusions 37, 37 'and the holes 38, 38' are formed at the base of the inner yoke. In the present invention, the protrusions 37, 37 'and the hole 3 are formed.
8, 38 'may be omitted. In this case, since there is no unevenness between the base of one inner yoke and the base of the other inner yoke, the stability (balance) on the magnetic circuit is good, and the various characteristics of the motor are improved.

The use of the motor of the present invention is not particularly limited. For example, the motor of the present invention may be of any type, such as focusing of an optical system in various optical devices or driving a lens for zooming.

In each of the illustrated embodiments, a PM type stepping motor has been described. However, the present invention is not limited to this. For example, a VR type or hybrid type stepping motor, or a DC motor (DC motor) may be used. ),
It can be applied to various motors such as a brushless DC motor.

[0116]

As described above, according to the motor of the present invention, the yoke (particularly, the outer yoke) of the stator and the rotor support member are provided with the positioning means for positioning them. The positioning between the stator and the rotor support member can be easily and reliably performed without using a jig.

Further, when the positioning means is a concave portion and a convex portion which engage with each other, particularly when a plurality of convex portions are provided along the rotating direction of the rotor, the stator and the rotor supporting member are provided. Can be performed more accurately.

The outer edge of the base of the inner yoke of the stator is exposed near the outer surface of the outer yoke, or the outer edge of the base of the inner yoke of the stator is positioned near the outer surface of the outer yoke. When exposed, the inner yoke and the outer yoke can be aligned based on the inner diameter of the stator.

A motor in which a rotor supporting member is installed (fixed) on both end surfaces of the stator, in particular, a plurality of magnetic poles formed on an inner yoke and a plurality of magnetic poles formed on an outer yoke When assembling stepping motors arranged alternately along the outer peripheral surface of the rotor while performing positioning based on the inner diameter, by positioning means,
Positioning of the stator and the rotor support member can be performed easily and reliably. In other words, the center axis of the assembled stator and the center axis of the rotor can be easily matched by the positioning means while performing the positioning based on the inner diameter.

As a result, the dimensional accuracy of the gap between each magnetic pole of the stator and the rotor is improved, and magnetic leakage is prevented, so that various characteristics of the motor are improved.
Variations in motor performance are prevented.

In particular, since a predetermined torque can be obtained with a lower input value (current), power consumption can be saved, the life of the battery can be prolonged, and rotation can be performed in a higher frequency range. In the case of a stepping motor, the angle accuracy is also improved.

Further, according to the motor assembling method of the present invention, a motor having the above-described excellent characteristics can be easily and reliably manufactured without complicating the manufacturing process, and can be mass-produced. Can respond.

[Brief description of the drawings]

FIG. 1 is a plan view showing an embodiment when a motor of the present invention is applied to a stepping motor.

FIG. 2 is a sectional view taken along line AA in FIG.

FIG. 3 is a plan view showing a configuration of a bottom plate (cover).

FIG. 4 is a bottom view showing the configuration of the outer yoke.

FIG. 5 is an exploded perspective view showing a configuration of an inner yoke and an outer yoke.

FIG. 6 is a plan view showing a configuration of an outer yoke.

FIG. 7 is a sectional view (end view) taken along line BB in FIG. 6;

FIG. 8 is a plan view showing a configuration of an inner yoke.

9 is a sectional view (end view) taken along line CC in FIG. 8;

FIG. 10 is a sectional side view showing the steps of the embodiment of the motor assembling method of the present invention.

FIG. 11 is a sectional side view showing the steps of the embodiment of the motor assembling method of the present invention.

FIG. 12 is a sectional side view showing the steps of the embodiment of the motor assembling method of the present invention.

FIG. 13 is a sectional side view showing an embodiment in which the motor of the present invention is applied to a stepping motor.

FIG. 14 is a sectional side view showing an embodiment in which the motor of the present invention is applied to a stepping motor.

FIG. 15 is a sectional side view showing an embodiment in which the motor of the present invention is applied to a stepping motor.

FIG. 16 is a graph showing a relationship between a driving speed and a torque of a stepping motor.

FIG. 17 is a graph showing a relationship between a driving speed of a stepping motor and a self-starting current.

FIG. 18 is a plan view showing a structure of a conventional stepping motor.

FIG. 19 is a sectional view taken along line DD in FIG. 18;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Stepping motor 2 Stator 3, 3 'Inner yoke 31, 31' Base 32 Outer peripheral edge 33 Opening 34 Magnetic pole 35, 36 Notch 37, 37 'Projecting part 38, 38' Hole 39 Butting surface 4, 4 'Outside Yoke 41 Bottom part 42 Outer part 421 End part 43 Opening 44 Magnetic pole 45, 46 Notch 47 Concave part 48 Convex part 5 Coil 51 Bobbin 52 Winding 53 Terminal part 531, 532 Terminal 54 Positioning protrusion 6 Rotor 60 Axis 61 Rotation axis 62 permanent magnet 7 bottom plate (cover) 71 circular opening 72 convex portion 73 concave portion 8 mounting plate 81 circular opening 82 convex portion 9a, 9b bearing 15 gap (gap) 21 jig 22 center pin (center pin with dowel) 221, 222 Positioning column part 23 Jig 24 Center pin (positioning column part) 100 Stepping motor 120 Stator 130 Inner yoke 131 Base 132 Outer edge 134 Magnetic pole 139 Abutting surface 140 Outer yoke 144 Magnetic pole 145 Stepped portion 150 Coil 160 Rotor 161 Rotary shaft 162 Permanent magnet 170 Gap (gap) 181 Bottom plate (cover) 182 Mounting plate 191, 192 bearing

Claims (14)

[Claims] A stator having a yoke and a coil, a rotor rotatably inserted inside the stator, a rotor support member installed on an end face of the stator and supporting the rotor. The motor according to claim 1, wherein the yoke and the rotor support member are provided with positioning means for positioning them. 2. A stator having at least one set of an inner yoke and an outer yoke and a coil disposed therebetween, a rotor rotatably inserted inside the stator, and an end face of the stator. A plurality of magnetic poles formed on the inner yoke, and a plurality of magnetic poles formed on the outer yoke, the outer peripheral surface of the rotor. A motor arranged alternately along the axis, wherein positioning means for positioning the outer yoke and the rotor support member are provided. 3. A stator having two sets of an inner yoke, an outer yoke, and a coil disposed therebetween, and a stator having the inner yokes joined to each other, and rotatably inserted inside the stator. A rotor, and a rotor support member installed on each end face of the stator to support the rotor; a plurality of magnetic poles formed on the inner yoke; and a plurality of magnetic poles formed on the outer yoke. Wherein the magnetic poles are alternately arranged along the outer peripheral surface of the rotor. At least one of the two sets of outer yokes and the rotor support member positions the outer yoke and the lid member. A motor provided with positioning means for performing the positioning. 4. The motor according to claim 2, wherein the inner yoke has a plate-shaped base, and an outer edge of the base is exposed near an outer surface of the outer yoke. 5. The inner yoke has a disk-shaped base having an outer diameter substantially equal to the outer diameter of the outer yoke, and an outer peripheral edge of the base is exposed near an outer peripheral surface of the outer yoke. The motor according to claim 2. 6. The rotor according to claim 2, wherein each of the magnetic poles of the inner yoke and the outer yoke is provided at a position in non-contact with the outer peripheral surface of the rotor and at the same distance from the rotation center of the rotor. The motor according to any one of the above. 7. The motor according to claim 1, wherein the positioning unit is configured to perform at least center axis alignment of the stator and the rotor support member. 8. The motor according to claim 1, wherein said positioning means is a concave portion and a convex portion engaged with each other. 9. The motor according to claim 8, wherein a height of the projection is 20 to 80% of a thickness of the rotor support member. 10. The motor according to claim 8, wherein a plurality of the protrusions are provided along a rotation direction of the rotor. 11. The motor according to claim 8, wherein the concave portion and the convex portion are formed simultaneously when press-molding a member on which the concave portion and the convex portion are formed. 12. The motor according to claim 1, wherein the outer diameter of the rotor is 1 to 30 mm. 13. A method for assembling a motor according to claim 4, wherein a coil is inserted between an inner yoke and an outer yoke, and the position of the inner yoke and the outer yoke is adjusted. A first step of assembling the stator by combining them while performing alignment, and inserting the rotor inside the stator to perform positioning while aligning the rotor support member with the outer yoke. A second step of coupling the child support member and the outer yoke, wherein the positioning of the inner yoke and the outer yoke in the first step is performed based on the inner diameter of the stator, The method of assembling a motor according to claim 2, wherein the positioning of the outer yoke and the rotor support member in the second step is performed by the positioning means. 14. The method according to claim 13, wherein the positioning of the inner yoke and the outer yoke is performed by inserting a jig into a bore of the stator.