JPH07322580A - Miniature motor - Google Patents

Abstract

PURPOSE:To prevent the deformation of an insulating board by bringing a part of the insulating board into contact with the outer end face of the core, and to keep the balance of the rotor by setting a constant length of winding at each part. CONSTITUTION:An insulating board 23 is formed of an insulating material, e.g. a resin material, to have a planar outline identical to that of the correction members 24, 25. A winding constituting a rotor 5 is then applied under a state where the insulating board 23 is positioned at the outer end faces of the correction boards 24, 25 with the region provided with a protrusion facing a core 6. Since the protrusion abuts against the outer end face of the core 6, a gap (g) is ensured even if the tension of winding is superposed thus preventing deformation of the insulating board 23. Consequently, the length of winding is made constant at any position of the armature core 3 and the correction members 24, 25 are held at predetermined positions without inclining thus keeping balance of the rotor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small motor in which an output shaft eccentric to the shaft center of a rotor is projected outward, and in particular, an unbalance due to rotation of the output shaft is adjusted. The present invention relates to a small motor configured to smoothly rotate a rotor.

[0002]

2. Description of the Related Art FIG. 7 is a vertical sectional front view of an essential portion showing an example of a small motor which is the subject of the present invention. In FIG. 7, reference numeral 1 denotes a housing, which is formed of a metal material such as soft iron into a hollow cylindrical shape with a bottom, and has a permanent magnet 2 formed in an arc segment shape fixed to the inner peripheral surface thereof. In this housing 1, a rotor 5 having an armature core 3 and a commutator 4 facing the permanent magnet 2 can be interposed. The armature core 3 includes a core 6 formed by stacking a large number of silicon steel plates in the axial direction, a rotary shaft 7 inserted and fixed to the core of the core 6, and a coil wound around the core 6 and rectified. The coil 4 is electrically connected to the child 4.

Next, 9 is an end cap, which is made of a metal material or a resin material, for example, in the shape of a bowl, and is fitted into the opening of the case 1. 10 is a brush holder,
The brush 13 is supported on a holder base 11 provided on the inner end surface of the end cap 9, and is formed so as to press the brush 13 against the outer peripheral surface of the commutator 4 via a spring 12, and the brush 13 slides on the outer peripheral surface of the commutator 4. It is formed so as to be in dynamic engagement. 14, 1
Reference numeral 5 denotes a bearing, which is fixed to the bottom of the housing 1 and the center of the end cap 9, and rotatably supports the rotary shaft 7 constituting the rotor 5 at both ends thereof. Reference numeral 16 denotes an output shaft, which is formed integrally with the rotary shaft 7 by eccentricizing the axial center of the rotary shaft 7 with the rotary shaft 7 and protruding outward from the end surface of the end cap 9.

With the above structure, an input terminal (not shown)
A permanent magnet fixed to the inner peripheral surface of the housing 1 by supplying a current to the coil 8 wound around the armature core 3 through the brush 13 and the commutator 4 that constitutes the rotor 5. Rotating force is applied to the rotor 5 existing in the magnetic field formed by 2, and the rotor 5 can be rotated. Therefore, the output shaft 16 protruding from the rotary shaft 7 can be reciprocated by a cylinder such as a hydraulic pump or other external equipment according to the eccentricity e.

However, when the rotor 5 rotates in the small motor having the above structure, the output shaft 16 is eccentric with respect to the rotary shaft 7 by the dimension e, so that the balance cannot be maintained.
There is an undesired problem that the rotor 5 does not rotate smoothly. Therefore, the balance is maintained by scraping off a part of the outer peripheral surface of the core 6 forming the armature core 3. However, in a small motor, since the armature core 3 has a small outer diameter, there is a drawback that a desired balance cannot be obtained only by cutting off a part of the outer peripheral surface of the core 6.

FIG. 8 is a front view of an essential part showing an example of the rotor unbalance adjusting means, and the same parts are designated by the same reference numerals as those in FIG. In FIG. 8, 17 is an output shaft,
It is formed so as to be eccentric from the rotating shaft 7 by the dimension e. 18
Is a putty that adjusts the unbalance due to the eccentric output shaft 17 by being fixed to the end surface of the core 6 that constitutes the armature core 3.

However, even if it is attempted to adopt a means for adjusting the imbalance only by the putty 18 shown in FIG. 8, since there is only a small space inside the small motor, the adjustment work is extremely complicated, so that it is very difficult. In addition to requiring time and man-hours, the putty 18 may peel off during the operation of the small motor, resulting in low reliability.

In order to eliminate the above-mentioned drawbacks, it has been proposed in FIG. 8 that the balance weights 19 and 20 are fixed to the rotary shaft 7 (see Japanese Patent Laid-Open No. 4-248345). That is, the balance weight 19 is inserted and fixed to the left rotary shaft 7 via the commutator 4 and the insulating plate 21, and the balance weight 20 is attached and fixed to the outer peripheral surface of the large diameter shaft 22 constituting the right rotary shaft. belongs to. With such a configuration, it is said that the effects of fixing the putty 18 can be eliminated, the imbalance can be adjusted, and the rotor 5 can be smoothly rotated.

[0009]

However, since the balance weights 19 and 20 are both fixed to the rotary shaft 7 and the large-diameter shaft 22 in the above-mentioned proposal, the balance weights 19 and 20 are Balance weight 19,2
There is a problem in that the distance to the center of gravity of 0 is small and the imbalance adjusting action is small. On the other hand, in order to increase the imbalance adjusting action, the size and weight of the balance weights 19 and 20 must inevitably be increased, which increases the weight of the rotor 5 as a whole, thus reducing the size and weight. However, there is a problem that it cannot be used as a small motor that needs to be made compact.

In addition to the above proposal, the length of the coil to be wound can be increased or decreased by changing the dimensions of the constituent parts of the core 6 which constitutes the armature core 3 (resulting in weight reduction. There is a proposal to adjust the unbalance of the rotor 5 by increasing / decreasing (see Japanese Patent Laid-Open No. 4-271256).
(See the official gazette). However, in this means, it is necessary to process the constituent parts of the core 6 or prepare a separate plate, which hinders the standardization of the members constituting the armature core 3 and reduces the productivity. There is.
Moreover, since the unbalance amount is reduced by increasing or decreasing the winding mass, there is a problem that the difference in winding resistance between the poles becomes large and the motor performance is adversely affected.

There is also a proposal of interposing other components in the vicinity of the output shaft 16 in FIG. 7 so as to deviate the center of gravity of these components from the axis of the rotary shaft 7 (for example, Japanese Patent Laid-Open No. Hei 4). -125044, Japanese Utility Model Laid-Open No. 1-147665, etc.). However, even in these proposals, the amount of deviation from the axis of the rotary shaft 7 is small, and the dimensions and weights of the constituent members must be limited.
As in the case shown in (1), there is a problem that the imbalance adjusting action is small.

Further, it has been proposed that the weights for adjusting the rotation balance are previously installed in the insulating plates 23 provided on both end surfaces of the core 6 shown in FIG.
However, since the insulating plate 23 is originally formed to have a small thickness in the axial direction, the weight of the weight to be installed inevitably becomes small. Therefore, there is a problem that the adjustment action of the imbalance is inevitably within the marginal range.

In order to solve the above-mentioned problems, one of the applicants has proposed that in a small motor having an eccentric output shaft, without increasing the axial size and weight of the rotor,
We have applied for an improved invention for a small motor that is capable of effective unbalance adjustment (Japanese Patent Application No. 5-305).
No. 034).

FIG. 1 is a front view of a main part of a rotor according to an embodiment of the improved invention described above, and the same parts are designated by the same reference numerals as those in FIG. In FIG. 1, reference numerals 24 and 25 denote correction members, which are fitted to the rotary shaft 7 and which are provided in the armature core 3
Is fixed to both end surfaces of the core 6 constituting the. Correction member 2
It is preferable that 4,25 are formed of a magnetic material having the same or similar characteristics as the core 6, for example, a silicon steel plate or a mild steel plate, and both are formed to have the same thickness dimension.

2 and 3 are plan views showing the correction members 24 and 25 in FIG. 1, respectively. 2 and 3, the correction members 24 and 25 are each formed in a pseudo fan shape, and a through hole 26 for fitting the rotary shaft 7 shown in FIG. 1 is provided. Reference numeral 27 denotes an arm portion, which is formed to have the same contour shape as the end face of the core 6, and the outer peripheral radius dimension r of the arm portion 27 is formed smaller than the outer radius dimension R of the core 6.

Next, the correction member 24 is replaced with the other correction member 25.
Since a larger amount of unbalance correction is required, the outer radius of the boss portion 28 is formed as small as possible as shown in FIG. 2, and its center of gravity and the center of the through hole 26 (see FIG.
(The same as the axial center of the rotating shaft 7), that is, the unbalance amount is increased, and the plate thickness for obtaining the required unbalance amount is determined. On the other hand, in the correction member 25, which does not require an unbalance amount as much as the correction member 24, the outer radius dimension of the boss portion 28 is formed larger than that in the correction member 24 in order to have the same material and plate thickness as the correction member 24. By providing a through hole 29 near the base of the arm portion 27 as necessary, the distance between the center of gravity of the arm portion 27 and the center of the through hole 26 is smaller than that in the correction member 24, that is, The balance correction amount is formed to have a required value.

When the correction members 24 and 25 are fitted on the rotary shaft 7, the center of gravity of the correction member 24 is set to the axial center of the output shaft 16 with respect to the axial center of the rotary shaft 7, as shown in FIG. The correction member 25 is fitted on the opposite side of the core 6 such that its center of gravity is located on the same side as the axis of the output shaft 16 with respect to the axis of the rotary shaft 7, and is fixed to both end surfaces of the core 6. To do.

With the above structure, the rotor 5 in FIG.
, The unbalance F due to the output shaft 16 provided eccentrically with the axis of the rotary shaft 7 (including the one due to the inertia of the external drive device) is fixed to both ends of the core 6. It can be offset by 25. That is, the correction member 2 fixed to both ends of the core 6
Since 4 and 25 are provided such that their respective centers of gravity are opposed to each other via the axis of the rotary shaft 7, a static balance is secured. Further, the unbalance F caused by an external device (not shown) driven by the output shaft 16 and the correction members 24, 2
The dynamic balance with the unbalances F ₁ and F ₂ due to 5 is secured. That is, the vector sum of the centrifugal force and the moment created by the centrifugal force can be brought to zero, or as close to zero as possible.

However, as a result of further continued study, it was found that the above-mentioned improved invention still has some improvements. That is, as shown in FIG.
Since the correction members 24 and 25 are sandwiched between the insulating plate 23 and the insulating plate 23, a gap g is inevitably formed between the core 6 and the insulating plate 23. On the other hand, since the insulating plate 23 is formed to have a relatively thin dimension, when the gap g is formed between the insulating plate 23 and the core 6 as described above, the winding for forming the rotor 5 is wound. Insulation plate 2 with winding tension superimposed
As a result of the deformation of 3 and the gap g being crushed, the correction members 24, 2
Rotor 5 in the part where 5 exists and the part other than that
Will have different lengths of windings. Further, when the gap g is crushed, the correction members 24 and 25 are inclined with respect to the plane orthogonal to the axis of the rotor 5, and the winding is inclined due to the superposition of the winding tension, resulting in a defective winding shape. In addition, there is a problem that the winding work is adversely affected and the balance of the rotor 5 is lost.

The present invention solves the above problems existing in the prior art and some problems in the improved invention, and in a small motor having an eccentric output shaft, without increasing the axial size and weight of the rotor. In addition, it is an object of the present invention to provide a small-sized motor capable of effective unbalance adjustment.

[0021]

In order to achieve the above object, according to the present invention, there is provided a housing formed of a metal material in the shape of a hollow cylinder with a bottom and having a permanent magnet fixed to an inner peripheral surface thereof, and the permanent magnet. A rotor having an armature core facing the magnet and a commutator; and a holder base fitted in the opening of the housing, and a brush slidably engaged with the commutator on the holder base. A brush holder for holding and a pair of input terminals electrically connected to the brush are provided to rotatably support the rotor and an output shaft eccentric to the shaft center of the rotor is outward. In a projecting small motor, correction members for correcting unbalance due to rotation of the output shaft are fixed to both ends of the core that constitutes the armature core, and these correction members are formed in a plate shape and Plane A technique in which a part of the shell shape is formed to be the same as or similar to the contour shape of the end surface of the core, and the insulating plate is formed so as to contact both the outer end surface of the correction member and the outer end surface of the core. Adopted the automatic means.

In the present invention, a plurality of protrusions may be provided at a portion of the insulating plate facing the core, and the protrusions may be formed so as to contact the outer end surface of the core. Further, in the present invention, the insulating plate may be formed so as to be substantially in close contact with the outer end surface of the core other than the outer end surface of the core that is in contact with the correction member.

In the above invention, the correction member can be formed of a magnetic material having the same or similar characteristics as the core. Further, in the above invention, it is preferable that the outer radius dimension of the correction member from the axial center of the rotor is smaller than the outer radius dimension of the core.

Further, in the above invention, it is preferable that the correction members fixed to both ends of the core have the same thickness.

[0025]

With the above structure, the unbalance generated by the eccentric output shaft when the rotor rotates can be canceled by the correction members fixed to both ends of the core to ensure the dynamic balance. The rotation of the child can be smoothed. Further, by providing the insulating plate with protrusions or by partially forming a large thickness dimension, a part or the whole surface of the insulating plate comes into contact with the core even in the region where the correction member does not exist, and the insulating plate It is possible to prevent deformation and inclination of the correction member, and to prevent inconsistencies in winding length.

[0026]

FIG. 4 is a plan view showing an insulating plate 23 in an embodiment of the present invention, FIG. 5 is a sectional view taken along line AA in FIG. 4, and FIG.
FIG. 6 is an enlarged sectional view of a B part in FIG. 4 to 6
In FIG. 2, the insulating plate 23 is made of an insulating material such as a resin material, and the correction members 24 and 2 shown in FIGS.
It is formed in the same planar contour shape as that of No. 5. That is, 30 is a boss portion, 31 is an arm portion, and the arm portion 31 is the boss portion 3.
A plurality of them are integrally formed on the outer periphery of 0 so as to radially project.

Reference numeral 32 is a fin-like projection, which has a substantially U-shaped cross-section (a plane parallel to a plane orthogonal to the motor axis) and is integrally provided at a side edge portion on the inner end side of the arm portion 31. . The projecting dimension H of these fin-shaped projections 32 is approximately 1/2 of the axial dimension of the core 6 shown in FIG. Next, 33 is a protrusion, and a plurality of protrusions are integrally provided with the arm portion 31 on the inner end side of the arm portion 31. The projection size h of the projection 33 is the thickness size or the gap g of the correction members 24 and 25 shown in FIG.
And the same size as.

The cross-sectional shape of the protrusion 33 may be a geometric shape such as a triangle, a quadrangle or the like other than the circular shape.
Although the protrusion 33 may be formed in a solid shape, a cavity 34 may be formed inside as shown in FIG. In order to form the insulating plate 23 having the structure shown in FIGS. 4 to 6, it is preferable to use, for example, a thermoplastic material and to perform injection molding.

The insulating plate 23 formed as described above is shown in FIG.
As shown in FIG. 3, the windings that configure the rotor 5 may be provided on the outer end surfaces of the correction members 24 and 25 and in a state where the regions provided with the protrusions 33 are positioned so as to face the core 6. That is, since the protrusion 33 is in contact with the outer end surface of the core 6, the gap g can be secured and the deformation of the insulating plate 23 can be prevented even if the winding tension is superimposed. Therefore, the winding length is the same regardless of the portion of the armature core 3, and the correction members 24 and 25 can also be held at a predetermined position without tilting.

In place of the protrusion 33 provided on the arm portion 31 shown in FIGS. 4 to 6, the thickness dimension of the arm portion 31 at the portion where the protrusion 33 is to be provided is set to be larger than the thickness dimension of other portions by h.
It may be formed in a large size. By doing this,
In, the insulating plate 23 directly contacts the outer end surface of the core 6 other than the outer end surface of the core 6 that contacts the correction members 24 and 25,
Alternatively, the protrusion 33 is substantially adhered to the protrusion 33.
It is possible to expect the same effect as that provided with.

In this embodiment, the holder base 11
Although an example has been described in which the end cap 9 is made of a resin material and is separate from the end cap 9 made of a metal material, both are integrally formed of a resin material and the holder base 11 is formed in the end cap 9. Even if there is, the present invention can be applied.

[0032]

EFFECTS OF THE INVENTION Since the present invention has the structure and operation as described above, the following effects can be obtained.

(1) Since a part of the insulating plate abuts the outer end surface of the core, the insulating plate is prevented from being deformed and the correction member is prevented from tilting, and the length of the winding wound around the armature core is set at each portion. They can be held at the same length, and the rotor balance can be maintained.

(2) Since the correction member is formed in a plate shape and is integrally fixed to both side surfaces of the core constituting the armature core, the axial length of the armature core can be adjusted by mounting the correction member. Increasing it more than necessary does not significantly increase the weight of the entire armature core.

(3) Since the distance between the center of gravity of the correction member and the axis of the rotary shaft can be made relatively large, the unbalance adjustment amount is increased even if the size and weight of the correction member are small. It is possible to reduce the size of the rotor.

(4) Since a part of the contour shape of the plane of the correction member is the same as or similar to the contour shape of the end surface of the core, there is no problem in winding the coil around the core. (5) By forming the correction member from a magnetic material having the same or similar characteristics as the core, the magnetic characteristics of the entire core are not affected.

(6) By forming the correction members fixed to both ends of the core to have the same thickness dimension, the correction members can be manufactured from the same plate material, which facilitates production control. Further, the insulating plates provided on both end surfaces of the core can be commonly used.

[Brief description of drawings]

FIG. 1 is a front view of essential parts showing a rotor according to an embodiment of the improved invention.

FIG. 2 is a plan view showing a correction member 24 in FIG.

3 is a plan view showing a correction member 25 in FIG.

FIG. 4 is a plan view showing an insulating plate 23 in the embodiment of the present invention.

5 is a cross-sectional view taken along the line AA in FIG.

FIG. 6 is an enlarged sectional view of a B part in FIG.

FIG. 7 is a vertical cross-sectional front view of essential parts showing an example of a small-sized motor as an object of the present invention.

FIG. 8 is a front view of a main portion showing an example of a rotor unbalance adjusting unit.

[Explanation of symbols]

 3 Armature Iron Core 4 Commutator 5 Rotor 6 Core 7 Rotation Shaft 16 Output Shaft 23 Insulation Plate 24, 25 Correction Member 33 Protrusion

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroaki Nakahashi 280, Ryugoji Temple, Motonomura, Inba-gun, Chiba Mabuchi Motor Co., Ltd.Technical Center (72) Inventor, Tadahiko Watanabe 280, Ryubeji Temple, Inba-gun, Chiba Prefecture Mabuchi Motor Co., Ltd. Company Technology Center

Claims (6)

[Claims] 1. A housing (1) which is made of a metal material and has a bottomed hollow cylindrical shape and has a permanent magnet (2) fixed to its inner peripheral surface, and an armature core (opposed to the permanent magnet (2). 3) and a commutator (4) and a rotor (5), and a holder base (11) fitted into the opening of the housing (1). The rotor (5) is provided with a brush holder (10) holding a brush (13) slidably engaged with the child (4) and a pair of input terminals electrically connected to the brush (13).
In a small motor in which the output shaft (16) eccentrically with respect to the shaft center of the rotor (5) is projected outward, the unbalance caused by the rotation of the output shaft (16) is supported. The correction members (24) and (25) for correcting the noise are fixed to both ends of the core (6) that constitutes the armature core (3), and the correction members (24) and (25) are plate-shaped. And a part of the contour shape of those planes is the same as or similar to the contour shape of the end face of the core (6), and the insulating plate (23) is provided outside the correction members (24) and (25). End face and core (6)
A small motor characterized in that it comes into contact with both the outer end surface of the motor. 2. A plurality of protrusions (33) are provided on a portion of the insulating plate (23) facing the core (6), and these protrusions (3) are provided.
3. The small motor according to claim 1, wherein 3) is formed so as to come into contact with the outer end surface of the core (6). 3. An insulating plate (23) is a correction member (24),
The small motor according to claim 1, wherein the small motor is formed so as to be substantially in close contact with the outer end surface of the core (6) other than the outer end surface of the core (6) that abuts against the (25). 4. The small motor according to claim 1, wherein the correction members (24), (25) are made of a magnetic material having the same or similar characteristics as the core (6). 5. The outer radius dimension (r) of the correction member (24), (25) from the axis of the rotor (5) is smaller than the outer radius dimension (R) of the core (6). The small motor according to any one of claims 1 to 4, which is characterized. 6. The small motor according to claim 1, wherein the correction members (24) and (25) fixed to both ends of the core (6) have the same thickness dimension. .