JP3437669B2 - Motor rotor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor rotor, and more particularly to a rotor provided with a varistor for eliminating contact sparks.

[0002]

2. Description of the Related Art In a conventionally known DC motor, a spark generated between a brush and a commutator affects a radio or the like. Therefore, a varistor is required to eliminate the spark. It is provided. The varistor has a ring shape, and the commutator is inserted through the central hole and soldered to a riser that connects the commutator and the coil.

However, when the varistor is attached by such a method, not only the number of soldering steps is increased, but also flux may fly to the surface of the commutator during the soldering step to prevent electrical contact with the brush. Further, in order to prevent the flux from adhering to the commutator, it is necessary to wrap the commutator surface, which is a troublesome work. Further, the varistor attached by soldering may have the solder melted by the heat of the coil and fall off.

Therefore, Japanese Utility Model Publication No. 4-124870 discloses a structure in which a varistor is pressed against and fixed to a riser by a pressing ring.

However, in the case of this structure, there is a problem that not only the pressing ring is required and the cost is increased, but also the pressing ring is easily removed by thermal deformation of the base of the commutator. That is, a resin base is interposed between the commutator and the rotary shaft in order to electrically insulate them from each other.
It is designed to be press-fitted on the outside of the base and the commutator.
Therefore, since the base is made of resin, the base may be deformed due to heat generation of the coil, which causes a problem that the holding ring comes off.

The present invention has been made to solve the above-mentioned conventional problems, and its purpose is to easily and rotatably mount a varistor on a motor so that the mounting state is not affected by heat. To provide.

[0007]

In order to achieve the above object, the invention according to claim 1 is a rotor of a motor in which a ring-shaped varistor is inserted from one end of a rotary shaft and provided near a commutator, A retaining means for preventing the varistor from coming off by contacting at least a part of the ring surface on the one end side of the rotary shaft in the varistor, and pressing the varistor in the direction of the retaining means from the surface opposite to the ring surface. Pressing means for holding the varistor by the retaining means and the pressing means, and at least one of the retaining means and the pressing means is integrally formed with a commutator piece constituting the commutator. The varistor and the commutator are electrically connected to each other.

According to a second aspect of the invention, in the motor rotor according to the first aspect, the retaining means is integrally formed of resin with a resin base for attaching the commutator to the rotary shaft. , Is elastically deformable in the direction of the center of the rotating shaft and is inserted into the ring hole of the varistor, and is expanded by a restoring force on the ring surface side of the varistor to prevent the varistor from coming off, and the pressing means constitutes the commutator. It is formed integrally with a commutator element for electrical connection between the varistor and the commutator.

According to a third aspect of the invention, in the rotor of the motor according to the first aspect, the varistor has an insertion portion formed in a ring hole to avoid the retaining means, and the retaining means is inserted from the insertion portion. When the varistor is inserted and protrudes toward the ring surface side, the varistor is rotated around the axis of the rotary shaft, and the removal preventing means is brought into contact with the ring surface side in the non-formation area of the insertion portion to be pulled out. The feature is to stop it.

According to a fourth aspect of the present invention, in the rotor of the motor according to the third aspect, the varistor of the rotary shaft is provided in a region where the retaining means comes into contact with the ring surface side to prevent the varistor from coming off. It is characterized in that it has a rotation stopping means for stopping the rotation around the axis.

According to a fifth aspect of the invention, in the rotor of the motor according to the third or fourth aspect, the retaining means and the pressing means are formed by cutting and bending one conductive plate to form the commutator piece. It is characterized by being integrally formed.

[0012]

According to the first aspect of the present invention, since the varistor is only sandwiched by the retaining means and the pressing means, the varistor can be easily attached, and an attaching member such as a holding ring is unnecessary. Moreover, since the electrical connection between the varistor and the commutator is achieved by at least one of the retaining means and the pressing means contacting or pressing the varistor, soldering is also unnecessary. Then, the pressing force brings the electrical contact into a stable state. Moreover, since the pressing means presses the varistor, even if the resin base is deformed by heating the coil, the varistor does not fall off immediately.

It is preferable that such a rotor is configured as in the invention according to claim 2 or 3, for example.

According to the second aspect of the present invention, the rotary shaft is inserted into the ring hole of the varistor, and the retaining means is inserted into the ring hole while elastically deforming in the central direction of the rotating shaft, and the retaining means is inserted from the ring surface. It is projected and spread by the restoring force to prevent it from coming off. Then, the pressing means formed integrally with the commutator piece serves to establish electrical conduction between the varistor and the commutator.

According to the third aspect of the present invention, while avoiding the retaining means by the insertion portion, the retaining means is inserted into the ring hole of the varistor, and the retaining means is projected to the ring surface side so that the shaft of the rotary shaft is rotated. The varistor is prevented from coming off by rotating it around.

Further, according to the invention described in claim 4, the varistor is prevented from rotating around the axis of rotation by the rotation stopping means. Therefore, since the varistor does not easily rotate due to vibration or the like, the varistor does not easily come off from the retaining means at the position of the insertion portion. Examples of the rotation stopping means include a groove into which the retaining means fits, a projection on which the retaining means is caught, and the like.

According to the fifth aspect of the invention, since both the retaining means and the pressing means are formed by cutting and bending one conductive plate, the manufacturing cost can be suppressed as compared with the case of using separate members. be able to.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 6 are views for explaining the first embodiment. 1 is a diagram showing a rotor according to the first embodiment.

In the figure, this rotor 10 is used for a small DC motor, and like the conventional one,
An armature core 14 is provided substantially in the center of the rotary shaft 12, and a coil 16 is wound around the armature core 14. Then, three commutator pieces 30 are provided on the resin base 20 to form a commutator, and a cap 18 is attached to an end of the commutator piece 30 to prevent the commutator piece from falling off.
Specifically, the commutator piece 30 is held by fitting one end into the groove 20a (see FIG. 3B) formed in the base 20 and attaching the cap 18 to the other end. Also, the commutator piece 3
A riser 19 connected to the coil 16 is integrally formed with the coil 0. The above-mentioned configuration is the same as the conventional one, and thus detailed description thereof will be omitted.

In this embodiment, a varistor 40 is attached in order to eliminate contact sparks generated between the brush (not shown) and the commutator (commutator piece 30). Have. The varistor 40 is a ring-shaped one having a ring hole 42 in the center,
The silver electrode 4 on the ring surface 46 on the side electrically connected to 0.
6a is provided.

A retaining piece 22 and a pressing piece 32 are used to attach the varistor 40, and the varistor 40 is sandwiched between them.

FIG. 2 shows the rotor before the varistor 40 is attached in order to explain the retaining pieces 22 and the pressing pieces 32. Furthermore, in order to explain the retaining piece 22,
FIG. 3 shows the rotor with the commutator piece 30, the cap 18, and the coil 16 removed.

As shown in FIGS. 2 and 3, the retaining pieces 22 are integrally formed with the resin base 20, and three retaining pieces 22 are formed around the rotary shaft 12 at equal angular intervals.
Specifically, as shown in FIG. 3 (B), the retaining piece 22 is formed on the upper side (the end side of the rotating shaft 12) of the outer peripheral wall of the groove 20a (described above) formed in the base 20. Thus, the outer peripheral wall has a shape that spreads outward.

More specifically, the retaining piece 22 is the rotary shaft 1.
A gap 24 wider than the groove 20a is formed on the second side,
The groove 20a is configured to form an inclined surface 26 that extends obliquely outward from the outer surface of the outer peripheral wall of the groove 20a and an outermost surface 28 that is located farthest from the rotation shaft 12 on the outermost peripheral side.

Then, as described above, the retaining piece 22.
Also, since it is molded with resin integrally with the base 20, it is elastically deformed. Therefore, the retaining piece 22 is inserted into the ring hole 42 (see FIG. 1A) of the varistor 40 while elastically deforming in the direction of the rotating shaft 12, and the inclined surface 26 of the retaining piece 22 is inserted into one ring of the varistor 40. Face 44 (Fig. 1
The varistor 40 can be prevented from coming off by bringing it into contact with the center end (see (B)) (the end where the ring hole 42 is formed).

More specifically, in order to prevent such disengagement, the retaining piece 22 has the following size.

That is, when the retaining piece 22 is elastically deformed in the direction of the rotating shaft 12, the inclined surface 26 is formed from the center of the rotating shaft 12.
The thickness of the retaining piece 22 and the gap 24 are set so that the distance to the diameter is smaller than the radius of the ring hole 42 of the varistor 40 so that the varistor 40 can be inserted.

When the retaining piece 22 is inserted into the ring hole 42 and the retaining piece 22 projects from the one ring surface 44, the retaining piece 22 gradually expands along the inclination of the inclined surface 26 due to the restoring force. Then, the distance from the center of the rotating shaft 12 to the inclined surface 26 becomes larger than the radius of the ring hole 42 of the varistor 40, so that the inclined surface 26 comes into contact with the end of the ring surface 44 to prevent coming off. The thickness of the retaining piece 22 and the gap 24 are set.

In this way, the varistor 40 is prevented from coming off by the retaining piece 22 on one ring surface 44 side, and is pressed by the pressing piece 32 on the other ring surface 46 side, and the varistor 40 is sandwiched by both. (See FIGS. 1 and 2).

Next, the pressing piece 32 will be described.
FIG. 4 is a diagram in which the pressing piece 32 and members integrally formed with the pressing piece 32 (commutator piece 30, riser 19) are extracted from FIG. 2A. In FIG. 4, three commutator pieces 30 are combined to form a commutator, and the pressing piece 3
2 is integrally formed with each commutator piece 30. One of the commutator pieces 30 and a member integrally formed with the commutator piece 30 (pressing piece 32, riser 19)
Is shown in FIG.

Further, the commutator piece 30 shown in FIG. 5 and members integrally formed with the commutator piece 30 (pressing piece 32, riser 19).
Is formed by cutting one conductive plate as shown in FIG. 6 and bending it. Specifically, the broken line in FIG. 6 is valley-folded at a right angle, the region serving as the commutator piece 30 is curved, and the tip end portion of the pressing piece 32 is slightly mountain-folded so as to be in the state shown in FIG. 5B. To form.

As described above, since the commutator piece 30, the pressing piece 32, and the riser 19 are formed of one conductive plate, they are electrically connected to each other.

Then, each pressing piece 32 has the structure shown in FIG.
As shown in (A), it is formed so as to extend in the tangential direction of the curved surface of each commutator piece 30. Therefore, as shown in FIG. 2, when the three commutator pieces 30 are attached to the base 20, the pressing piece 32 is integrated with the commutator piece 30, so that the three pressing pieces 32 are provided in the tangential direction. Become. Further, the tip end portion of the pressing piece 32 is bent so as to face upward in FIG. 2 (B).

Since the pressing piece 32 is formed in this way, when the varistor 40 is attached as shown in FIG.
The tip of the pressing piece 32 is the other ring surface 4 of the varistor 40.
6 is pressed. Then, as described above, since the varistor 40 is prevented from coming off by the retaining piece 22, the varistor 40 is sandwiched between the retaining piece 22 and the pressing piece 32.

In addition to this, the pressing piece 32 is the commutator piece 3
Since it is electrically connected to 0, the varistor 40 and the commutator piece 30 are electrically connected by pressing and contacting the ring surface 46 of the varistor 40. Since the silver electrode 46a is provided on the ring surface 46 of the varistor 40, the electrical connection is good.

As described above, according to the first embodiment, the varistor 40 can be easily attached only by fitting it while elastically deforming the retaining piece 22. Further, soldering is unnecessary, and the varistor 40 can be properly held by the pressing force of the pressing piece 32.

Next, the second embodiment of the present invention will be described with reference to FIG.
~ It demonstrates based on FIG. FIG. 7 is a diagram showing a rotor according to the second embodiment. The feature of this rotor is that the varistor 60 is sandwiched by the retaining piece 52 and the pressing piece 54 which are integrated with the commutator piece 50. The commutator piece 50 is provided with the riser 19 of the first embodiment. A similar riser 56 is also integrally formed. The other points are the same as those in the first embodiment, and the description thereof will be omitted.

FIG. 8 is a diagram showing a process of attaching the varistor in the order of (A) and (B) by extracting the characteristic portion of the second embodiment. Further, FIG. 9 is a front view showing a state in which a varistor is held, corresponding to FIG. 8 (B).

As shown in these figures, the varistor 60
Are sandwiched between the retaining pieces 52 and the pressing pieces 54.

FIG. 10 is a plan view of a member for sandwiching this varistor, and FIG. 11 shows one commutator piece, and a retaining piece and a pressing piece integrated with the commutator piece among the members shown in FIG. It is a figure. Further, FIG. 12 is a development view of the members shown in FIG.

As shown in FIG. 11, the retaining piece 52 is formed so as to rise from the curved surface of the commutator piece 50 in the normal direction. The formation position is shown in FIG.
As shown in (B), it is located above the pressing piece 54 in the figure. Therefore, a space is formed between the retaining piece 52 and the pressing piece 54, and the space between the retaining piece 52 and the pressing piece 54 is set to be slightly smaller than the thickness of the varistor 60, so that the pressing force of the pressing piece 54 is applied to sandwich the varistor 60. You can

The pressing piece 54 and the riser 56 are the same as the pressing piece 32 and the riser 19 in the first embodiment, and are formed by cutting and bending one conductive plate as shown in FIG.

In addition to this, in the second embodiment, since the retaining piece 52 is also formed by cutting and bending the conductive plate, the retaining piece 52, the pressing piece 54, and the riser 56.
Can be formed simultaneously.

Next, the varistor 60 will be described. FIG. 13 is a diagram showing a varistor, (A) is a plan view,
(B) is a sectional view taken along line BB in (A), and (C) is a bottom view.

As shown in FIG. 13, the varistor 60 includes
A ring hole 62 is formed in the center. This ring hole 6
2 has a shape close to a round triangle, and a concave portion 64 is formed at a side portion of the round triangle (see FIG. 13B). As shown in FIG. 8B, the recess 64 has a shape such that the retaining piece 52 is caught. further,
As shown in FIG. 8A, the apex portion of the round triangle has a shape and size that can avoid the retaining piece 52. Also,
A silver electrode 60a is provided on the bottom side of the varistor 60.

The process of attaching the varistor 60 thus formed will be described with reference to FIG. First, FIG.
As shown in (A), the commutator piece 50 is inserted into the ring hole 62 of the varistor 60, and the retaining piece 52 is arranged and further inserted into the round triangular vertex of the ring hole 62. Then, one surface of the varistor 60 is pressed by the pressing piece 54.
(See FIG. 9).

Further, when the varistor 60 is pressed until the pressing piece 54 is elastically deformed, the retaining piece 52 projects from the other surface of the varistor 60, so that the varistor 60 is moved in the direction indicated by the arrow in FIG. 8A. To rotate. Then, the retaining piece 52 fits into the recess 64, and the attachment is completed at this position.

The second embodiment is constructed as described above, and according to this, both the retaining piece 52 and the pressing piece 54 are formed by cutting and bending a single conductive plate.
The manufacturing cost can be suppressed as compared with a separate member.

The varistor 6 is used in the second embodiment.
The silver electrode 60a is provided on the bottom side of the
Since the varistor 60 and the commutator piece 50 are electrically connected to each other by both the pressing piece 54 and the pressing piece 54, the silver electrode 60a may be provided on the upper surface side without being limited to the bottom surface side of the varistor 60.

[0051]

According to the present invention, the varistor can be easily attached, the attaching member such as the pressing ring can be omitted, and the soldering for electrical connection can be omitted.
Further, the pressing force can stabilize the electrical contact between the varistor and the commutator, and even if the base is deformed by heat, the mounting state of the varistor is not easily affected.

[0052]

[Brief description of drawings]

FIG. 1 is a view showing a rotor according to a first embodiment of the present invention, (A) is a plan view and (B) is a front view.

FIG. 2 is a diagram showing a state before a varistor is attached to the rotor in the first embodiment, (A) is a plan view,
(B) is a front view.

3A and 3B are diagrams showing a state before attaching a varistor and a commutator to a rotor in the first embodiment, FIG. 3A being a plan view and FIG. 3B being a longitudinal sectional view.

FIG. 4 is a diagram showing a commutator and a pressing unit in the first embodiment.

5A and 5B are views showing a commutator piece and a member integrated with the commutator piece in the first embodiment, wherein FIG. 5A is a plan view, FIG. 5B is a front view, and FIG.

FIG. 6 is a development view of the member shown in FIG.

7A and 7B are views showing a rotor according to a second embodiment of the present invention, in which FIG. 7A is a plan view and FIG. 7B is a front view.

FIG. 8 is a view showing a mounting state of the varistor in the second embodiment and a mounting step in the order of (A) and (B).

FIG. 9 is a view showing a mounting state of a varistor in the second embodiment.

FIG. 10 is a view showing a varistor mounting means in the second embodiment.

11A and 11B are views showing a commutator piece and a member integrated with the commutator piece in the second embodiment, FIG. 11A being a plan view and FIG.
Is a front view and (C) is a side view.

12 is a development view of the member shown in FIG.

FIG. 13 is a diagram showing a varistor in the second embodiment,
(A) is a plan view, (B) is a sectional view taken along line BB in (A), and (C) is a bottom view.

[Explanation of symbols]

10 Motor rotor 12 rotation axes 20 base 22 Stopping piece (stopping means) 30 commutator piece 32 pressing piece (pressing means) 40 Barista 42 ring hole 50 commutator piece 52 retaining piece 54 Pressing piece (pressing means) 60 Barista

Continuation of the front page (72) Inventor Ishikawa ▲ Toshi ▼ Male, 390 Umeda, Kosai City, Shizuoka Prefecture Asmo Co., Ltd. (56) References U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02K 23/66 H02K 11/00

Claims (5)

(57) [Claims] 1. A rotor of a motor in which a ring-shaped varistor is inserted from one end of a rotating shaft and is provided in the vicinity of a commutator, the varistor being in contact with at least a part of a ring surface on the one end side of the rotating shaft of the varistor. Retaining means for preventing the varistor from coming off and a pressing means for pressing the varistor in the direction of the retaining means from the surface opposite to the ring surface, and the varistor is secured by the retaining means and the pressing means. At least one of the retaining means and the pressing means is formed integrally with a commutator piece that constitutes the commutator, so as to establish electrical conduction between the varistor and the commutator. Characteristic motor rotor. 2. The rotor for a motor according to claim 1, wherein the retaining means is integrally formed of resin with a resin base for attaching the commutator to the rotating shaft, and is arranged in a center direction of the rotating shaft. Elastically deformable to be inserted into the ring hole of the varistor and spread by a restoring force on the ring surface side of the varistor to prevent the varistor from coming off, and the pressing means is integrated with a commutator piece forming the commutator. A rotor of the motor, which is formed in a desired manner to establish electrical connection between the varistor and the commutator. 3. The rotor for a motor according to claim 1, wherein the varistor has an insertion portion formed in a ring hole to avoid the retaining means, and the retaining surface is inserted through the insertion portion to form the ring surface. The retaining means is projected to the side, the varistor is rotated around the axis of the rotating shaft, and the retaining means is brought into contact with the ring surface side in the non-forming region of the insertion portion to prevent the retaining. And the rotor of the motor. 4. The rotor of the motor according to claim 3, wherein the varistor rotates about the axis of the rotating shaft in a region where the retaining means comes into contact with the ring surface to prevent the retaining. A rotor for a motor, comprising a rotation stopping means for stopping the motor. 5. The rotor for a motor according to claim 3 or 4, wherein the retaining means and the pressing means are integrally formed with the commutator piece by cutting and bending one conductive plate. A rotor of a motor characterized in that