JP3736472B2 - Method for bonding permanent magnet to stator and yoke for rotating armature - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a stator for a rotary armature and a method for adhering a permanent magnet to a yoke thereof.
[0002]
[Prior art]
A DC motor (DC motor), which is a type of rotating armature, includes a commutator (commutator) and a brush, and includes an outer fixed stator (stator) and an inner rotating rotor (rotor). One type of such a DC motor with a brush is one in which a stator is composed of a cylindrical yoke (junction) and a field permanent magnet (hereinafter abbreviated as “permanent magnet”) fixed to the inner peripheral surface thereof. . The yoke magnetically connects adjacent magnetic poles of the permanent magnet, is made of a magnetic material such as iron, and has a cylindrical shape. The permanent magnet generates a main magnetic flux, and a plurality of permanent magnets are circumferentially arranged on the inner peripheral surface of the yoke.
[0003]
The permanent magnet is bonded to the inner peripheral surface of the yoke by an adhesive, but before the permanent magnet is bonded, the surface including the inner peripheral surface of the yoke is subjected to surface treatment for rust prevention or the like. At that time, a zinc plating layer is first formed on the surface of the yoke for rust prevention, and then a chromate layer is formed on the zinc plating layer by a chromate treatment for rust prevention of the zinc plating layer and decoration of the yoke. May form. Although the zinc plating layer is inexpensive, a certain degree of rust prevention effect can be obtained. The chromate layer has a large antirust effect and a decorative effect.
[0004]
[Problems to be solved by the invention]
By the way, the chromate layer generally contains a trace amount of moisture. In particular, the yellow chromate layer using hexavalent chromium absorbs moisture in the atmosphere and self-repairs the portion that has been torn by scratches or the like with this moisture. Thus, the yellow chromate layer is easily regenerated, and moisture is present therein.
[0005]
This moisture may prevent the permanent magnet from adhering to the yoke after the surface treatment of the yoke. For example, after the formation of the zinc plating layer and the chromate layer, a thermosetting adhesive is applied to the surface of the chromate layer, and the permanent magnet is adhered to the yoke with this adhesive. Thereafter, when the adhesive is dried by applying heat, the moisture in the chromate layer evaporates due to heating during drying, and accordingly, a part of the adhesive applied thereon is repelled.
[0006]
As a result, the substantial adhesion area between the outer surface of the permanent magnet and the inner peripheral surface of the yoke is reduced, and the adhesive force of the permanent magnet by the adhesive is reduced. In particular, when a yellow chromate layer containing hexavalent chromium is formed, this tendency becomes remarkable because the amount of water retained is larger than that of other chromate layers.
[0007]
The present invention has been made in view of the above circumstances, and even when a chromate layer is formed on the yoke for rust prevention and / or decoration of the yoke constituting the stator for the rotary armature, the permanent magnet to the yoke by the adhesive is used. An object of the present invention is to provide a stator for a rotary armature that can prevent a decrease in the adhesive strength of the rotor, and a method for adhering a permanent magnet to a yoke in the stator.
[0008]
[Means for Solving the Problems]
The inventor of the present application provides a method for forming a chromate layer in which a chromate layer is not formed between a permanent magnet and a portion on a plating layer on a plating layer on the inner peripheral surface of a yoke and application of an adhesive during chromate treatment. The method was conceived and the present invention was completed.
[0009]
According to a first aspect of the present invention, the stator for a rotary armature includes a cylindrical yoke made of a magnetic material and having a plating layer formed on at least an inner peripheral surface thereof, and a plurality of stators on the plating layer. from a plurality of permanent magnets bonded by an adhesive without forming a chromate layer on the pieces of the magnet bonding portions, a chromate layer formed on the magnet unbonded portion excluding the plurality of magnets bonded portions on the plating layer It is characterized by comprising.
[0010]
In this stator for a rotary armature, the chromate layer is not formed at the magnet adhesion portion on the plating layer, and the permanent magnet is firmly adhered to the inner peripheral surface of the yoke by an adhesive. And the magnet non-bonding part is rust-proofed and decorated by the chromate layer.
[0011]
According to a second aspect of the stator for a rotary armature, in the first aspect, the plating layer is made of a zinc plating layer. According to this stator, an excellent antirust effect can be obtained while being inexpensive.
[0012]
According to a third aspect of the stator for a rotary armature, in claim 2, the chromate layer is mainly composed of chromium. According to this stator, a further excellent rust prevention effect and decorative effect can be obtained.
[0013]
On the other hand, the method for adhering a permanent magnet to a yoke according to the second invention of the present application is, as described in claim 4, on a plating layer made of a magnetic material and formed on at least the inner peripheral surface of a cylindrical yoke. a masking step of masking a plurality of magnets bonded portion in the mask member, and the chromate layer forming step of forming a chromate layer on the magnet unbonded portion that is not masked by the mask members on the plating layer, a plurality of removing the mask member It comprises a magnet bonding step in which an adhesive is applied to each magnet bonding portion, and a plurality of permanent magnets are bonded to the plurality of magnet bonding portions with the adhesive.
[0014]
In this method of adhering a permanent magnet to a yoke, a chromate layer is formed on a non-magnet adhering portion with the magnet adhering portion masked by a mask member, and then the permanent magnet is adhered to the magnet adhering portion by an adhesive. Thus, the chromate is prevented from entering between the yoke and the permanent magnet.
[0015]
In the permanent magnet bonding method according to the fifth aspect, in the masking step according to the fourth aspect, the plurality of magnet bonding portions are simultaneously masked by a masking unit including a plurality of mask members. According to this bonding method, a plurality of magnet bonding portions are efficiently masked.
[0016]
In the permanent magnet bonding method according to a sixth aspect of the present invention, in the masking step of the fourth aspect, the plurality of yokes are simultaneously masked by a masking device comprising a plurality of masking units. According to this bonding method, the magnet bonding portions of the plurality of yokes are masked more efficiently.
[0017]
In the permanent magnet bonding method according to the seventh aspect, in the magnet bonding step according to the fourth aspect, the permanent magnet is bonded using the edge formed by the chromate layer on the periphery of the magnet bonding portion in the plating layer forming step. According to this bonding method, positioning of the inner peripheral surfaces of the yokes of the plurality of permanent magnets on the plating layer is easy and reliable.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
<Rotating armature>
The present invention can be applied to starters (starting motors) and generators for automobiles, drive motors for industrial equipment, motors for electric tools, and the like. A DC motor therein is fixed to the outside and has a generally cylindrical stator (stator), a rotor (rotor or armature) rotatably disposed in the internal space of the stator, a commutator (commutator), and And a permanent magnet for the field. Known commutators and brushes can be used, and known rotors can also be used.
<Stator>
As described above, the stator includes a yoke, a surface treatment layer (plating layer and chromate layer), and a plurality of permanent magnets.
(1) The yoke is made of a magnetic material such as iron and has a cylindrical shape. It is desirable that a plating layer having excellent rust prevention properties is formed on at least the inner peripheral surface and the entire surface (the inner peripheral surface, the outer peripheral surface, and both end surfaces) as much as possible. If a zinc plating layer is employed as the plating layer, a relatively high rust prevention capability can be obtained while being inexpensive (corresponding to claim 2). The thickness of the zinc plating layer can be 5 to 30 μm.
{Circle around (2)} The chromate layer is formed by a chromate treatment, and further imparts corrosion resistance to the yoke on which the zinc plating layer or the like is formed, and can give several kinds of colors. Here, “chromate treatment” is to immerse a yoke or the like in an aqueous solution containing chromic acid or dichromic acid as a main component to form a coating film that is stable against corrosion. Specific examples of chromate include yellow chromate and white chromate. The yellow chromate has a yellow appearance, and the white chromate has a glossy silver white color.
[0019]
The chromate layer should just be formed in the magnet non-bonding part on the plating layer formed in the inner peripheral surface of the yoke at least. Here, the “magnet bonding portion” is a portion (region) to which the permanent magnet on the plating layer on the inner peripheral surface of the yoke is bonded, and the “magnet non-bonding portion” is the plating layer on the inner peripheral surface. The rest of the above. On the plating layer on the inner peripheral surface, the magnet bonded portions and the magnet non-bonded portions are alternately positioned in the circumferential direction. The shape and number of the magnet bonded portion and the magnet non-bonded portion are determined by the shape and number of the permanent magnet. The thickness of the chromate layer is formed in the range of 0.3 to 1.5 μm. Further, when the plating layer is formed on a portion other than the inner peripheral surface of the yoke, the chromate layer is preferably formed also on that portion. If the chromate layer is formed on the zinc plating layer (corresponding to claim 3), the rust prevention effect by the zinc plating layer and the chromate layer and the decoration effect by the chromate layer can be obtained.
{Circle around (3)} As the permanent magnet, a rare earth magnet that can obtain a large magnetic force with a small shape, or a ferrite magnet can be adopted. There is no restriction | limiting in particular in the shape of a permanent magnet, What is necessary is just to have the outer surface of the curvature same as the inner peripheral surface of a yoke at least. The number of permanent magnets can be 2, 4, 6, or 8.
(4) As an adhesive for adhering the permanent magnet to the yoke, a known thermosetting adhesive (for example, epoxy resin) can be used.
<Adhesion method>
As described above, the method for adhering the permanent magnet to the yoke includes the masking step, the chromate layer forming step, and the magnet adhering step.
(1) In the masking step, first, a plating layer is formed on at least the inner peripheral surface of the yoke. The plating layer is desirably formed on the inner peripheral surface and other surfaces (outer peripheral surface, both end surfaces). Zinc can be used when forming the plating layer. The plurality of magnet adhesion portions on the plating layer may be masked by a single mask member, or may be masked by a plurality of mask members. When a plurality of mask members are used, the plurality of magnet adhesion portions may be masked sequentially (one by one), but it is desirable to mask simultaneously with consideration of work efficiency and the like.
[0020]
In order to simultaneously mask a plurality of magnet adhesion portions, for example, a masking unit composed of a plurality of mask members can be used (corresponding to claim 5). Each mask member only needs to have a size capable of masking at least each magnet bonding portion, but it is desirable to have the same shape as the magnet bonding portion. In addition, rubber | gum etc. can be employ | adopted for the material of a mask member. If a masking device comprising a plurality of masking units is used, a plurality of yokes can be masked simultaneously (corresponding to claim 6).
[2] The chromate layer forming step may be formed chromate layer on the non-adhesive portion magnet except the plurality of magnets bonded portion. However, the magnet bonding portions in the bonding method of the present invention because it is masked by the mask member can be subjected to stretch chromate treatment to the entire plating layer of the inner peripheral surface.
[3] In the magnet bonding step, the plurality of mask members are removed, and an adhesive is applied sequentially or simultaneously to each of the plurality of magnet bonding portions where the chromate layer is not formed. Next, each permanent magnet is bonded to each magnet bonding portion by manual operation or an automatic machine. For example, when the permanent magnet is bonded manually, a rectangular frame-shaped edge formed by the chromate layer around the magnet bonding portion in the chromate layer forming step can be used as a mark (corresponding to claim 7).
[0021]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
(DC motor stator)
As shown in FIGS. 1, 2, and 3, the stator 30 includes a cylindrical yoke 10 and four permanent magnets 20 bonded to the inner peripheral surface 11 thereof. The yoke 10 is made of iron, has a cylindrical shape with both ends opened, and has a uniform thickness in both the axial direction and the circumferential direction. Zinc plating layers (hereinafter referred to as “zinc coating”) 13 and 14 are formed on the inner peripheral surface 11 and the outer peripheral surface 12 of the yoke 10 (see FIG. 5F). The thickness of the zinc films 13 and 14 is 5 to 30 μm. A zinc film is also formed on both end faces 15a and 15b of the yoke 10.
[0022]
Four permanent magnets 20 are bonded to four magnet bonding portions 16 on the zinc film 13 on the inner peripheral surface 11 via an adhesive 18 (see FIG. 5F). The adhesive 18 is thermosetting, and is applied to four rectangular magnet bonding portions 16 formed on the zinc film 13 with a 90-degree separation in the circumferential direction.
[0023]
A curved thin rectangular plate-shaped permanent magnet 20 is bonded on each magnet bonding portion 16. Each permanent magnet 20 has an inner surface 21 and an outer surface 22, a pair of end surfaces 23a and 23b, and a pair of side surfaces 24a and 24b. The thickness is uniform throughout the longitudinal and transverse directions. The length in the short direction is such that a gap 26 is formed between the adjacent permanent magnets 20, and the length in the longitudinal direction is slightly shorter than the length of the yoke 10. Of the four permanent magnets 20 , two have N poles and two have S poles, and are arranged so that the N poles and the S poles face each other.
[0024]
A chromate layer (hereinafter referred to as “chromate film”) 27 is formed on the non-magnetized part 17 of the zinc film 13 on the inner peripheral surface 11 (see FIG. 5F). That is, only the adhesive 18 exists between the zinc film 13 and the outer surface 22 of the permanent magnet 20, and the chromate film 27 does not exist. A chromate film is also formed on the zinc film 14 on the outer peripheral surface 12 and the zinc films (not shown) on both end surfaces 15a and 15b.
[0025]
Accordingly, the adhesive 18 is not repelled by the moisture in the chromate film 27 on the magnet bonding portion 16, and the permanent magnet 20 is firmly bonded to the magnet bonding portion 16 by the adhesive 18 over the entire outer surface 22. Further, since the zinc film and the chromate film are formed on the outer peripheral surface 12 of the yoke 10 which may be touched by human eyes, the rust prevention effect is improved and the decoration effect is also obtained.
(Adhesion method of permanent magnet to yoke)
Next, a method for bonding the permanent magnet 20 to the yoke 10 in the stator 30 will be described. As shown in FIGS. 4 and 5, the mounting method includes a pretreatment step S1, a galvanizing step S2, a masking step S3, a chromate treatment step S4, a drying step S5, an adhesive application step S6, and a magnet adhesion step S7.
[0026]
In the pretreatment step S1, preparations for forming the zinc coatings 13 and 14 are made. As shown in FIG. 5 (a), alkaline cleaning to dissolve and remove the oil and fat component X on the inner peripheral surface 11 of the yoke 10, first acid cleaning to remove the oxide film and rust, electrolytic cleaning to finish removal of the oxide film, And a second acid cleaning for activating the yoke 10.
[0027]
In the galvanizing step S2, as shown in FIG. 5 (b), zinc coatings 13 and 14 and the like of zinc are formed on the inner peripheral surface 11 and the outer peripheral surface 12 of the yoke 10 and the both end surfaces 15a and 15b after the pretreatment. . At this time, electroplating is used to set zinc as an anode and a yoke 10 as a cathode in an aqueous metal salt solution. Then, the zinc of the anode is electrolyzed by energization of current and deposited on the surface of the yoke 10 to form the zinc films 13 and 14 and the like.
[0028]
Here, after the zinc plating step S2, an activation step for removing the coating on the surface of the zinc coating 13 is executed.
[0029]
In the masking step S3, as shown in FIG. 5C, the four magnet adhesive portions 16 on the zinc film 13 are simultaneously masked by the four mask members 31 of the masking unit. As shown in FIG. 6, the masking unit 40 includes a cross member 42 having four support portions 41, and a quadrant-shaped mask member 31 made of rubber attached to the tip of each support portion 41 at the tip. . The curvature of the outer surface of each mask member 31 is made equal to the curvature of the inner peripheral surface 11 of the yoke 10, and the outer diameters of the mask members 31 facing each other in the diametrical direction are made slightly larger than the inner diameter of the inner peripheral surface 11 of the yoke. Yes. The circumferential length of the mask member 31 is substantially equal to that of the inner surface 21 of the permanent magnet 20, and the axial length is substantially equal to that of the inner surface 21 of the permanent magnet 20.
[0030]
The yoke 10 is inserted in the axial direction from one opening and attached to the masking unit 40. With the insertion, the outer surface side portion of each mask member 31 is elastically deformed radially inward, and the four magnet adhesion portions 16 on the zinc coating 13 are simultaneously and reliably masked.
[0031]
In addition, as shown in FIG. 7, a plurality of masking units 40 are arranged on a frame 46 to form a masking device 45. Therefore, the yokes 10 of the plurality of stators 30 can be masked at the same time, and work efficiency is increased accordingly.
[0032]
The above pretreatment step S1, galvanization step S2, activation step and masking step S3 correspond to the masking step in the invention described in claim 1.
[0033]
In the chromate treatment step S4, as shown in FIG. 5 (d), chromate is applied to the non-masked portion 17 on the inner peripheral surface 11 of the surface of the yoke 10, the outer peripheral surface 12, and both end surfaces 15a and 15b. A film 27 is formed. That is, the yoke 10 in which the magnet adhesion portion 16 is masked by the mask member 31 is immersed in the chromic acid solution for several seconds. _{Then, C r 2 O 3 · xH} 2 O oxide film That chromate film 27 mainly composed of is formed on the zinc coating.
[0034]
This chromate treatment step S4 corresponds to the chromate layer forming step in the invention described in claim 1.
[0035]
After the chromate film 27 is formed, each yoke 10 is removed from each masking unit 40. Then, a rectangular line (edge) 28 is formed by the chromate film around the magnet adhesion portion 16 where the chromate film 27 is not formed. Next, the chromate film 27 is dried in the drying step S5.
[0036]
In the adhesive application step S6, as shown in FIG. 5 (e), a thermosetting adhesive 18 is applied to the magnet adhesive portion 16 where the chromate film 27 is not formed. Here, the adhesive 18 is applied manually by the operator, and is applied at least in the region surrounded by the line (edge) 28 on the zinc film 13. In the magnet bonding step S7, as shown in FIG. The permanent magnet 20 is bonded onto the applied adhesive 18. Or adhesive application step S6, and magnet bonding step S7 is corresponding to the magnet bonding process in the invention recited in claim 1.
[0037]
The permanent magnet 20 needs to be positioned at predetermined positions in the axial direction and the circumferential direction on the zinc coating 13, but here, a rectangular line (edge) 28 is formed on the zinc coating 13. Therefore, the permanent magnet 20 can be easily and easily positioned and bonded to the magnet bonding portion 16 by using the edge 28 as a mark.
[0038]
【The invention's effect】
As described above, according to the stator for a rotary armature of the present invention, the adhesive applied to the magnet adhesion portion is hardly repelled by the chromate layer, and the permanent magnet is firmly attached to the magnet adhesion portion by the adhesive. It is glued. Moreover, the magnet non-adhered portion is prevented from being rusted by the plating layer and the chromate layer, and has an effect of improving the appearance.
[0039]
On the other hand, according to the method for adhering a permanent magnet to the yoke of the present invention, it is possible to prevent the chromate from entering the magnet adhesion portion when forming the chromate layer, and to reliably apply the adhesive to the magnet adhesion portion. The effect that can be produced.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing one embodiment of a stator for a rotary armature according to the present invention.
FIG. 2 is a plan view of the stator for a rotary armature shown in FIG.
FIG. 3 is an enlarged view of a main part of FIG. 2;
FIG. 4 is a flowchart showing one embodiment of a method for adhering a permanent magnet to a yoke according to the present invention.
5 (a), (b), (c), (d), (e), and (f) illustrate the relationship among a yoke, a plating layer, a chromate layer, an adhesive, and a permanent magnet in the bonding method shown in FIG. It is explanatory drawing.
6 is a perspective explanatory view of a masking unit used in the bonding method of FIG. 4;
7 is an explanatory perspective view of a masking device in which a plurality of masking units in FIG. 6 are arranged. FIG.
[Explanation of symbols]
10: Yoke 11: Inner peripheral surface 13: Zinc coating 16: Magnet bonding portion 17: Magnet non-bonding portion 18: Adhesive 20: Permanent magnet 22: Outer surface 27: Chromate coating 28: Edge 30: Stator 31: Mask member 40: Masking unit 45: Masking device

Claims (7)

A cylindrical yoke made of a magnetic material and having a plating layer formed on at least the inner peripheral surface;
A plurality of permanent magnets adhered by an adhesive without forming a chromate layer on the plurality of magnet adhesion portions on the plating layer;
A chromate layer formed on a magnet non-adhesion portion excluding the plurality of magnet adhesion portions on the plating layer;
A stator for a rotary armature, comprising:   The stator for a rotary armature according to claim 1, wherein the plating layer is a zinc plating layer. The stator for a rotary armature according to claim 2, wherein the chromate layer contains Cr ₂ O ₃ .xH ₂ O as a main component. A masking step of masking a plurality of magnet adhesion portions on a plating layer formed of a magnetic material on at least an inner peripheral surface of a cylindrical yoke with a mask member;
A chromate layer forming step of forming a chromate layer on the magnet unbonded portion that is not masked with the mask member on the plating layer,
A magnet bonding step of the mask member by applying a plurality of adhesive to the magnet adhered portion was removed, bonding the plurality of the permanent magnets into a plurality of magnet bonding portions by adhesive,
A method for adhering a permanent magnet to a yoke, comprising:   The method of adhering a permanent magnet to a yoke according to claim 4, wherein, in the masking step, the plurality of magnet adhesion portions are simultaneously masked by a masking unit comprising a plurality of the mask members.   5. The method of adhering a permanent magnet to a yoke according to claim 4, wherein in the masking step, the plurality of yokes are simultaneously masked by a masking device comprising a plurality of the masking units.   5. The method for adhering a permanent magnet to a yoke according to claim 4, wherein, in the magnet adhering step, the permanent magnet is adhered to the periphery of the magnet adhering portion in the plating layer forming step using the edge formed by the chromate layer as a mark. .

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