JP2000184662A - Small dc motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a relatively small DC motor wherein no lead wire is required to be soldered to a rigid terminal while an insert hole in which the rigid terminal is inserted can be omitted. SOLUTION: A rotor 6 and a commutator 7 are fixed to a shaft 5 inside a motor case 1 to which an annular magnet 2 is fixed, a rigid terminal 9 supporting a brush piece 12 sliding to the commutator 7 is fixed to an insulating resin bracket 3 which is, facing the commutator 7, fixed to the motor case 1, and an external lead wire 13 is connected to the rigid terminal 9. Here, a flat bent base part 12b which is bent almost light angle to the brush piece 12 is molded so that the bent base part 12b is fixed to a connection end 9a of the rigid terminal 9, a slot 8 in which the bent base part 12b and the connection end 9a are inserted at the same time is formed at a resin bracket 3, an insert hole 14 in which the lead wire 13 is inserted from outside is formed at the resin bracket 3 while approaching the slot 8, and a core wire 13a of the lead wire 13 exposed from an inner end part of the insert hole 14 is directly contacted to the connection end 9a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small DC motor, and more particularly to a connection structure between a brush and an external lead wire.

[0002]

2. Description of the Related Art As is well known, a small DC motor as shown in FIG. 3 is manufactured as follows. A ring-shaped magnet C polarized in the circumferential direction is fixed to the inner peripheral surface of the motor case B whose open end is closed by the insulating resin bracket A. A shaft F is rotatably supported between a bearing E at the center of the inside of the resin bracket A.

[0003] A rotor G and a commutator H composed of a yoke and windings are fixed to the middle of the shaft F inside the motor case B. The commutator H has a thick rigid terminal. A pair of flexible brush pieces J supported by I are in sliding contact.

That is, as shown in FIG. 4, a pair of insertion holes K into which the rigid terminals I can be inserted are formed in a resin bracket A to be injection-molded, and a brush piece J is formed in an upper mounting end i1.
Are rigidly inserted into the corresponding insertion holes K, respectively. Further, for the external connection, the core 11 of the lead wire L is fixed to the connection end i2 of each rigid terminal I projecting outside the resin bracket A by soldering.

[0005]

However, according to such a conventional connection structure between the brush and the external lead wire, the connection end i2 of each rigid terminal I is connected to the core wire l1 of the lead wire L.
Must be connected one by one, which not only complicates the assembling process but also heats the rigid terminal I and the brush piece J, which require processing accuracy, for soldering the core wire 11 of the lead wire L. However, there is a problem that they are lately thermally deformed by heating during soldering. Further, in the case of a small DC motor having a small outer diameter such as a cored motor, it is difficult to secure a space for forming the insertion hole K in the resin bracket A, and the lead wire L to be used becomes thin. Is growing.

SUMMARY OF THE INVENTION In view of the above-described conventional connection structure between a brush and an external lead wire, the object of the present invention is to eliminate the need to solder a lead wire to a rigid terminal each time. An object of the present invention is to provide a relatively small and small DC motor which can omit an insertion hole for allowing the DC motor to pass therethrough.

[0007]

According to the present invention, a rotor and a commutator are fixed to a shaft inside a motor case to which a ring-shaped magnet is fixed, and the motor case is fixed to the motor case facing the commutator. In a small DC motor in which a rigid terminal supporting a brush piece slidingly contacting the commutator is fixed to an insulative resin bracket to be fixed and an external lead wire is connected to the rigid terminal, the brush terminal is substantially perpendicular to the brush piece. A bent flat base is formed and the bent base is fixed to the connection end of the rigid terminal, and a slot in which these bent base and the connection end can be inserted at the same time is formed in the resin bracket. An insertion hole in which the lead wire can be inserted is formed in the resin bracket in a state close to the slot, and the lead is exposed from an inner end of the insertion hole. The core wire is to propose a small DC motor for direct contact with the connection end.

In the following description of a preferred embodiment of the present invention, 1) a structure in which a core groove for receiving the core is connected to the inner end of the insertion hole, and 2) a fixing means such as an adhesive. The structure which is fixed inside the insertion hole by using will be described.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. FIG. 1 shows a small DC motor according to the present invention, and although not shown, a ring-shaped magnet 2 which is circumferentially polarized is fixed to an inner peripheral surface of a motor case 1, and a bearing of the motor case 1 and the aforementioned The rotor 6 and the commutator 7 each composed of a yoke and a coil are fixed to the intermediate portion of the shaft 5 between the resin bracket 3 and the bearing 4 as in the conventional case.

The resin bracket 3 for closing the open end of the motor case 1 is injection-molded from an insulating resin, and an arc-shaped peripheral wall 3a surrounding the commutator 7 is integrally formed at the inner end thereof. is there. A pair of opposing pressing walls 3b are integrally formed at both ends of the arc-shaped peripheral wall 3a, and slots 8 corresponding to the inner surface of the resin bracket 3 are formed below these pressing walls 3b. A connection end 9a of a rigid terminal 9, which will be described in detail later, can be inserted into each of the slots 8.

On the outer peripheral surface of the resin bracket 3 facing each of the slots 8, a pair of side recesses 10 for receiving the mounting ends 9b of the corresponding rigid terminals 9 are formed, and these side recesses 10 have connection ends 9a. The fitting end 9b of the rigid terminal 9 bent at a right angle to is fitted. That is, the flexible brush piece 12 located in the space 11 surrounded by the arc-shaped peripheral wall 3a is made of a thin flexible metal plate, and is a sliding portion that can slide on the peripheral surface of the commutator 7. 12a
One end of each of the sliding portions 12a has a bent base portion 12b bent at a right angle in a substantially horizontal direction.

The rigid terminal 9 made of a relatively thick conductive metal plate has a connection base 9b of the same size and shape as the bent base 12b of the corresponding brush piece 12, and these connection ends 9a The bent base portion 12b of the brush piece 12 is spot-welded in a laminated state, and a mounting end 9b having a shape corresponding to the side recess 10 is bent at one end of the connection end 9a at a right angle.

On the other hand, a pair of penetrating insertion holes 14 through which a lead wire 13 for external connection can be inserted is formed at a position adjacent to each slot 8, and these insertion holes 14 are formed from below the resin bracket 3. Lead wires 13 can be inserted respectively. Since a shallow core groove 15 communicating with each of the insertion holes 14 is formed on the inner surface of the resin bracket 3,
The exposed core wire 13 a of the lead wire 13 inserted into the corresponding insertion hole 14 can be located in the concentric wire groove 15.

Since the small DC motor according to the illustrated embodiment has the structure described above, the brush piece 12, the rigid terminal 9, and the lead wire 13 can be assembled to the resin bracket 3 in the following steps. it can. First, the rigid terminals 9
The bent base portion 12b of the brush piece 12 is spot-welded to the connection end 9a, and the lead wire 13 excluding the coating at the tip is inserted into the insertion hole 14 of the resin bracket 3, and the core wire 13a at the tip end of the lead wire 13 is It is located in the groove 15. In this case, the subsequent process is facilitated by fixing the lead wire 13 inside the insertion hole 14 using an adhesive or the like.

Next, as shown in FIG. 2, the rigid terminal 9 to which the brush piece 12 is fixed is located on the side of the resin bracket 3, and the flat connection end 9a of the rigid terminal 9 and the brush piece 12 are fixed.
Is tightly inserted into the slot 8, and the mounting end 9b of each rigid terminal 9 is fitted into the corresponding side recess 10 of the resin bracket 3. When the mounting end 9b is engaged with the side recess 10, rigidity is obtained. When the terminal 9 is secured in the resin bracket 3 and the connection end 9a and the bent base portion 12b are inserted into the slot 8, the core 13a of the lead 13 located in the core groove 15 as shown in FIG. , Rigid terminal 9
Is strongly contacted with the lower surface of the connection end 9a.

As a result, the core wire 13a of the lead wire 13 and the brush piece 12 can be kept electrically conductive without any soldering. , The brush piece 12 can be reliably brought into sliding contact with the commutator 7. Further, in the illustrated embodiment, the insertion hole 14 having a diameter corresponding to the lead wire 13 may be formed in the resin bracket 3.
A much smaller and smaller DC motor can be obtained as compared with a structure in which an insertion hole for mounting the rigid terminal 9 is formed in the bracket resin.

[0017]

As is apparent from the above description, according to the present invention, the bent base of the brush piece is fixed to the flat connection end of the rigid terminal, and the connection end is inserted into the slot of the resin bracket. Thus, since the rigid terminal and the core wire of the lead wire are brought into contact with each other, an external connection structure can be obtained without requiring heating such as soldering. Further, according to the present invention, since an insertion hole for fixing the rigid terminal is not formed on the surface of the resin bracket, a relatively small DC motor can be obtained.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view of a main part of a small DC motor according to the present invention.

FIG. 2 is an exploded perspective view of a main part of the small DC motor.

FIG. 3 is a partially cutaway side view of a conventional small DC motor.

FIG. 4 is an exploded perspective view of a main part of the small DC motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor case 3 Resin bracket 3a Arc-shaped peripheral wall 3b Holding wall 5 Shaft 6 Rotor 7 Commitator 8 Slot 9 Rigid terminal 9a Connection end 9b Mounting end 10 Side recess 12 Brush piece 12a Sliding portion 12b Bend base 13 Lead wire 13a Core wire 14 Insertion hole 15 Core groove

Claims (3)

[Claims] 1. A rotor and a commutator are fixed to a shaft inside a motor case to which a ring-shaped magnet is fixed, and the commutator is slidably contacted with an insulative resin bracket fixed to the motor case facing the commutator. In a small DC motor in which a rigid terminal supporting a brush piece is fixed and an external lead wire is connected to the rigid terminal, a flat bent base bent substantially at right angles to the brush piece is formed and bent. A base is fixed to the connection end of the rigid terminal, a slot in which the bent base and the connection end can be inserted at the same time is formed in the resin bracket, and an insertion hole through which the lead wire can be inserted from the outside is close to the slot. Formed on the resin bracket, and the core wire of the lead wire exposed from the inner end of the insertion hole is brought into direct contact with the connection end. Small DC motor. 2. The small DC motor according to claim 1, wherein a core wire groove for receiving the core wire is connected to an inner end of the insertion hole. 3. The small DC motor according to claim 1, wherein the core wire is fixed inside the insertion hole using fixing means such as an adhesive.