JPH03173330A - Motor and assembling method thereof - Google Patents

Abstract

PURPOSE:To facilitate positioning and securing of a magnet by fitting the magnet in an opening made in the housing body and securing the magnet in place. CONSTITUTION:A tubular body 11 having one open end and a cover 12 to be secured at the open end side of the tubular body 11 are provided, where the tubular body 11 and the cover 12 constitute the housing body. The tubular body 11 comprises a drum section 11a to be fixed with the cover 12, a bottom section 11b, and a stay section 11c elongated in the axial direction and coupling the drum section 11a and the bottom section 11b. A space surrounded by the drum section 11a, the bottom section 11b and the stay section 11c provides an opening, i.e., a pocket section 11d, opposing the outer circumferential face of a rotary shaft 3, and a magnet 5 is fitted in each pocket section 11d. By such method, positioning and securing of the magnet 5 are facilitated.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to improvements in electric motors and assembling methods thereof, and in particular, to improvements in electric motors that can be made lighter, lower in price, and more efficient in assembly work. This is what I did.

[Conventional technology]

As a conventional electric motor, there is, for example, one shown in FIG. 3 (first conventional example).

FIG. 3 is a partially cutaway front view of a conventional electric motor 1 that is relatively suitable for mass production. A rotating shaft 3 is rotatably supported within a cylindrical housing 2. , an armature 4 including a coil 4a and the like is fixed.

A left portion (not shown) of the coil 4a of the armature 4 is connected to a power source via a known commutator, brush, or the like so that power can be supplied.

On the other hand, on the inner surface of the housing 2, on the surface facing the commutator 4, there are a plurality of magnets 5.5 having poles in the vertical direction in the figure.
They are arranged so as to sandwich the armature 4 therebetween.

Each of the magnets 5, 5 holds the ring members 6a and 6b in place (
(not shown), and is press-fitted and fixed together with the magnet holder 6 into the inner surface of the housing 2. Note that when the magnet holder 6 is not used, the magnet 5 is fixed to the inner surface of the housing 2 by adhesive or the like.

Therefore, in the electric motor 1 of this first conventional example, the housing 2 also serves as a yoke that forms a magnetic circuit between the outer surfaces of the magnets 5 .

Then, when current is supplied to the coil 4a of the armature 4,
As is well known, rotational force is generated in the rotating shaft 3, and is transmitted from the output end 3a of the rotating shaft 3 to external equipment.

Further, as another example of the conventional electric motor 1, there is one shown in FIGS. 4 and 5 (second conventional example).

4 is a partially cutaway front view of the electric motor 1, and FIG. 5 is a partially cutaway front view of the electric motor 1.
It is a sectional view taken along the line B-B in the figure, and the same members as in FIG. 3 include:
The same symbols are attached. However, in FIG. 5, the illustration of the coil 4a of the armature 4 is omitted.

That is, in this second conventional example, the housing 2 in the first conventional example is replaced with a front cover 2a and a rear cover 2.
b and a cylindrical yoke 2c, and a magnet 5
．． 5 is fixed to the inner peripheral surface of the yoke 2c by adhesive. In addition, in FIG. 4, 7 is a commutator, 8 is a brush, and 9 is a brush holder. In FIG. 5, 10.10 connects the front cover 28 and the rear cover 2b, and the front cover 2a, This is a bolt that integrates the rear cover 2b and yoke 2c.

Similarly to the first conventional example, in this second conventional electric motor 1, when a current is supplied to the coil 4a of the armature 4, rotational force is generated in the rotating shaft 3, and the output of the rotating shaft 3 is End 3a
The rotational force is transmitted from the to the external equipment.

As described above, the electric motors 1 of the first and second conventional examples have a relatively simple structure, and therefore have the advantage of being easy to downsize.

[Problem to be solved by the invention]

Here, the conventional electric motor 1 can be easily miniaturized as described above, but in order to make a high-output electric motor while taking advantage of the advantage of easy miniaturization, it is necessary to use a high-performance magnet as a magnet. It is necessary to use a rare earth IU61 stone (for example, neodymium-iron-boron system) (which provides a high magnetic flux density), and in that case, the following problems arise.

That is, in the normal electric motor 1, the magnet 5 may be magnetized (magnetized) before being fixed to the housing 2 or the yoke 2c, or may be magnetized along with the yoke 2c after being fixed. If an attempt is made to directly position and adhere the magnet 5 to the inner peripheral surface of the yoke 2c, the strong magnetic force of the magnet 5 will be an obstacle, and the workability of positioning and adhesion will be very poor, making mass production impossible.

In addition, the method of magnetizing the magnet 5 after bonding it to the yoke 2c improves work efficiency because positioning and bonding can be done easily, but there are restrictions on the magnetic material on the magnetizer side, so the rare earth magnet cannot be sufficiently magnetized. As a result, a high-performance electric motor cannot be obtained. Although it would be easy to fully exploit the capabilities of rare earth magnets by using special materials with high magnetic permeability, this would make the manufacturing itself expensive, and the manufacturing cost of electric motors would increase dramatically. The disadvantage is that it can rise to

As described above, there are drawbacks that differ depending on the point at which the magnet 5 is magnetized, but there is no point in using expensive rare earth magnets unless a high-performance electric motor is obtained.
The magnet 5 is magnetized in advance before being fixed to the housing 2, and the magnetized magnet 5 is held in the magnet holder 6 and positioned outside the housing 2, as explained in the first conventional example above. Then, the magnet 5 together with the magnet holder 6 is forcibly pushed into the housing 2.

However, if rare earth magnets are used to increase the magnetic flux density interlinking with the armature (approximately three times), it is necessary to increase the thickness of the housing 2 that forms the magnetic circuit to reduce magnetic resistance. 1 In the conventional example, the housing 2 also serves as a yoke, so if you try to increase the thickness of the yoke, the thickness of the entire housing 2 will increase, that is, the thickness of unnecessary parts will also increase. Naturally, since the housing 2, which also serves as a yoke, is made of iron, the weight of the electric motor 1 increases significantly. Furthermore, since the housing 2 shown in FIG. 3 is usually formed by a pressing process, if the thickness of the entire housing 2 increases, the pressing process becomes difficult, which increases manufacturing costs. will occur.

In addition, when the structure of the second conventional example is configured such that the magnet 5 is forcibly pushed into the yoke 2C using the magnet holder 6 as shown in the first conventional example, the front cover 2a and the rear cover 2b are made of iron material. Since the yoke 2C may be molded from other light materials and it is easy to increase the thickness of only the yoke 2C, it does not have the drawbacks that occurred in the first conventional example.

However, in the second conventional example, a bolt 10 is required to integrate the housing, and the bolt 10 is surrounded by a yoke 2c, an armature 4, and a magnet 5.5, as shown in FIG. It has to pass through a space, but since a part of the stem of the magnet holder 6 passes through this space, the bolt lO must eventually pass through that part.

Therefore, the strength of the stem part of the magnet holder 6 and the strength of the bolt 10
In order to achieve both 0 strength (i.e. outer diameter dimension of 10), it is necessary to increase the wall thickness of the stem part.
When the wall thickness of a portion of the stem increases, the diameter of the armature 4 that rotates close to the stem must be reduced.

If the diameter of the armature 4 is made smaller, the gap between the armature 4 and the magnet 5 will become larger and the performance of the electric motor 1 will deteriorate. It is necessary to increase the thickness. However, as is well known, the rare earth magnets used to improve performance can be formed into thin walls and exhibit sufficient performance, so increasing the thickness of the magnet 5 is unnecessary. Moreover, rare earth magnets are expensive, which further increases the cost of the magnet 5, that is, the cost of the electric motor 1, which is not practical.

Although it is possible to arrange the bolt lO outside the yoke 2C, this has the disadvantage that the parallelism between the two force bars 2a and 2b becomes poor and the size of the electric motor l, which is desired to be small, increases.

Therefore, the present invention has been made by focusing on the unresolved problems of the conventional technology, and aims to improve assembly efficiency and avoid unnecessary weight and cost increases. The object of the present invention is to provide an electric motor and a method for assembling the same.

(Means for Solving the Problems) In order to achieve the above object, an electric motor according to claim (1) includes a rotary shaft rotatably supported within a hollow housing, and an armature attached to the rotary shaft. is fixed to the housing, a magnet that generates a magnetic flux in a direction interlinking with the armature is fixed to the housing, and the electric motor further includes current supply means for supplying current to the armature. It is composed of a main body that rotatably supports a rotating shaft and has an opening facing the outer peripheral surface of the rotating shaft, and a yoke that is fitted onto the main body so as to cover the opening, and the magnet is connected to the main body. It was inserted into the opening and fixed.

Further, the method for assembling an electric motor according to claim (2) includes the steps of assembling an electric motor according to claim (1) above.
After a magnetized magnet is fitted from the outside of the opening and fixed to the main body of the housing, a yoke is fitted onto the main body so as to cover the magnet and the opening.

(Function) In the electric motor according to claim (1), since the magnet is fitted into the opening provided in the main body of the housing and fixed, even if the magnet is magnetized, its positioning and fixing are easy. It's easy to do.

Further, since the main body of the housing and the yoke are separate members, it is easy to make only the yoke from iron material and increase the thickness of only the yoke.

In the method for assembling an electric motor according to claim (2), the magnet is fitted and fixed from the outside of the opening of the housing body, and then the yoke is fitted on the outside, so that assembly is easy.

〔Example] Embodiments of the present invention will be described below based on the drawings.

1 and 2 are diagrams showing one embodiment of the present invention. FIG. 1 is a front sectional view of the electric motor 1, and FIG. 2 is a sectional view taken along the line A--A in FIG. 1. Note that the same reference numerals are given to the same members as those of the conventional electric motor described above, and redundant explanation thereof will be omitted.

First, the configuration will be explained.

That is, in this embodiment, a cylindrical body 11 with one end open is used.
and a cover 12 fixed to the open end side of the cylindrical body 11 with, for example, bolts, and the cylindrical body 11 and the cover 12 constitute the main body of the housing.

The cylindrical body 11 includes a body portion IIa to which the cover 12 is fixed;
It is composed of a bottom portion 11b and a stem portion 11c that is long in the axial direction and connects the body portion 11a and the bottom portion flb. However, the body portion 11a.

The bottom part 11b and the stay part 11c are integral, and in this embodiment, as shown in FIG. is seperated.

A space surrounded by the body portion 11a, the bottom portion 11b, and the stem portion 11c faces the outer peripheral surface of the rotating shaft 3.
A pocket portion lid is formed as an opening of the present invention, and a magnet 5 is fitted and fixed in each pocket portion 1], d.

That is, a concave portion 11e continuous in the axial direction is formed on the side surface (surface forming the pocket portion 11d) of each stem portion 11c, and a concave portion 11e continuous in the axial direction is formed on the corresponding surface of the magnet 5.
A convex portion 11f is formed to match the concave portion 1c, and the concave portion IIe and the convex portion 11f fit together, and the magnet 5 is fitted into the blur ν1 portion lid.

Four magnets 45 fixed to each pocket lid...
, 5, one of the pair of magnets 5.5 facing the rotating shaft 3 has a NJS surface facing the rotating shaft 3.
The surface facing the C side is the south pole, and the other pair of magnets 5, 5 facing the rotating shaft 3 have the surface facing the RIB shaft 3 side as the south pole, and the surface facing the yoke 2C side as the north pole. be. Therefore, since each magnet 5 communicates magnetic flux with the two magnets 5 on both sides thereof, each magnet 5. . . , 5 and the yoke 2C, four magnetic circuits are formed, and each magnet 5.
...The magnetic flux flowing between the coils 5 intersects each conductor of the coil 4a at right angles.

The cylindrical body 11 includes a cylindrical yoke 2c with both end faces open, and pocket portions 11d, . . . .

cover the lid and each magnet 5. . . , is fitted onto the outside in contact with the outer surface of 5.

Further, the rotating shaft 3 has a bearing 13a fixed to the cover 12.
It is rotatably supported by a bearing 13b fixed to the bottom 11b of the cylindrical body 11, and its output end 3a passes through a substantially central portion of the cover 12 and is located outside.

Four brushes 8 (two of the four not shown) spaced 90 degrees apart in the circumferential direction are attached to the cover 12 via four brush holders 9 (two of the four not shown). The tips of these brushes 8 are connected to the coil 4 of the armature 4.
It is in contact with the outer peripheral surface of a known commutator 7 connected to the end of a. Further, each brush holder 9 is connected to a DC power source via a harness or the like (not shown). Here, in this embodiment, commutator 7. The brush 8 and brush holder 9 constitute a current supply means.

Therefore, with the above configuration, if a current is supplied to the coil 4a of the armature 4 via the brush 8, commutator 7, etc., a rotational force is generated in the rotating shaft 3, as is well known. Rotational force is transmitted from the output end 3a to external equipment.

Next, of the method for assembling the electric motor 1 having the above structure, steps that are characteristic of the present invention will be described.

That is, each magnet 5 is fitted and fixed into the pocket lid from the outside of the cylindrical body 11 before the yoke 2c is fitted onto the outside. At that time, an adhesive or the like may be applied to the inner surface of the pocket lid, but the magnet 5 may be fitted and held only by the recess lie of the pocket 11d and the projection 11f of the magnet 5. However, it is also possible to press the yoke with a jig such as an hour wheel until it is press-fitted.

After the magnet 5 is fixed, the yoke 2c is attached to the cylindrical body 1.
Fit it onto 1. That is, it is sufficient to slide the yoke 2C from the bottom 11b side of the cylindrical body 11 and push it in until the end surface of the yoke 2C comes into contact with the step 11g of the body 11a. Note that the yoke 2C is composed of, for example, two gutter-like semi-cylindrical members obtained by dividing a cylindrical body, and after sandwiching the cylindrical body 11 between these semi-cylindrical members, the two-handed cylindrical members are integrated by gluing, bolting, etc. By doing so, the yoke 2c may be fitted onto the cylindrical body 11.

As described above, with the configuration of this embodiment, the positioning and fixing of the magnet 5 can be performed very easily, so even if the magnet 5 that has been magnetized in advance is fixed, the assembly work will not be difficult. do not have. Therefore, when rare earth magnets are used to improve the performance of the electric motor 1, the magnets can be sufficiently magnetized until the desired performance is exhibited, making it easy to realize a high-performance electric motor 1. can.

Since the yoke 2c and the cylindrical body 11 are separate members, only the yoke 2c can be made of iron, and the other members can be made of relatively lightweight materials (aluminum die-cast, resin, etc.). Minute yoke 2 using rare earth magnets
Even if the thickness of C is increased, the thickness of the cylindrical body 11 etc. does not have to be increased unnecessarily, and the weight of the electric motor 1 does not increase excessively. In other words, the electric motor 1 can be made lighter and less expensive.

Furthermore, since vibrations occur when the electric motor 1 is driven, it is desirable to connect the cylindrical body 11 and the cover 12 using bolts.
For example, the body 11a of the cylindrical member 11 and the cover 12 can be made of synthetic resin that is easy to mold.
All you need to do is provide a screw hole for the bolt in the flange part of
There is no need for a structure in which the bolt 10 passes through the entire structure as in the second conventional example.

Therefore, there is no need to increase the thickness of the magnet 5 unnecessarily, so even if an expensive rare earth magnet is used, the thickness of the magnet 5 can be made thin, and the price of the electric motor 1 will not increase significantly. .

In the second conventional example, the housing may be integrated using bolts that connect the front cover 2a and the yoke 20 and bolts that connect the rear cover 2b and the yoke 20. If this configuration is adopted, holes for bolt fastening must be provided at both ends of the yoke 2c, which unnecessarily increases the thickness of the yoke 2C and increases the weight of the electric motor 1. Since it is made of a relatively hard material such as iron, it is difficult to process compared to resin or the like, and there are problems in that the manufacturing cost increases.

Furthermore, with the configuration of this embodiment, the magnet 5 is attached to the pocket portion 1.
Since the edge part of the magnet 5, which is easily broken because it is held within the pocket 1d, is inside the pocket lid, the missing magnet 5
The risk of debris entering the rotating shaft 3 side is small, and the occurrence of motor locking that occurs when such debris gets caught between the magnet 5 and the armature 4 is reduced.

With the configuration of the above embodiment, it is possible to realize a small, high-performance electric motor l that is lightweight and inexpensive. It can be suitably used in fields where a motor is required and the space for installing an electric motor is limited.

In the above embodiment, four magnets 5. .

Further, the shapes of the cylindrical body 11 and the yoke 2C constituting the housing are not limited to the above embodiments, and may be other shapes such as a box shape.

(Effects of the Invention) As described above, according to the present invention, an electric motor is connected to a main body that rotatably supports a rotating shaft and has an opening, and a yoke that is fitted externally to the main body so as to cover the opening. In addition to configuring the housing, the magnet is fitted into the opening of the housing body and fixed, so even a magnetized magnet can be easily positioned and fixed, so assembly work can be performed efficiently. Since only the yoke can be made of iron material and it is easy to increase the thickness of only the yoke, the electric motor can be made lighter and less expensive.
Since there is no need for bolts that pass through both ends of the housing, there is no need to increase the thickness of the magnet unnecessarily, so even if expensive rare earth magnets are used, the cost will not increase dramatically.Furthermore, Various effects such as being able to reduce the risk of motor locking can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view showing the configuration of one embodiment of the present invention;
The figures are a sectional view taken along the line A-A in Fig. 1, Fig. 3 is a front sectional view showing an example of a conventional electric motor, Fig. 4 is a front sectional view showing another example of a conventional electric motor, and Fig. 5 is a sectional view taken along the line B-B in FIG. 4. DESCRIPTION OF SYMBOLS 1... Electric motor, 2C... Yoke, 3... Rotating shaft, 4... Armature, 5... Magnet, 7... Commutator,
8... Brush, 9... Brush holder (7 to 9 are current supply means), 11... Cylindrical body (main body), lid...
Pocket part (opening), 12...Cover (main body)

Claims (2)

[Claims] (1) A rotating shaft is rotatably supported in a hollow housing, an armature is fixed to the rotating shaft, and a magnet that generates magnetic flux in a direction interlinking with the armature is fixed to the housing; Further, in an electric motor including a current supply means for supplying current to the armature, the housing includes a main body that rotatably supports the rotating shaft and has an opening facing the outer circumferential surface of the rotating shaft; An electric motor comprising: a yoke externally fitted onto the main body so as to cover the opening; and the magnet is fitted and fixed into the opening of the main body. (2) The magnetized magnet is fitted from the outside of the opening and fixed to the main body of the housing, and then a yoke is fitted onto the main body so as to cover the magnet and the opening. How to assemble an electric motor.