JP2022129238A - Motor and manufacturing method for the same - Google Patents

Abstract

To suppress reduction in reliability of a motor due to resin powder or debris.SOLUTION: A brushed motor 10 includes a bus bar 28 having conductivity and a boss 20e made of resin and having a groove 20g into which the bus bar 28 is inserted. The boss 20e has a dissolving portion 20i that closes an opening part of the groove 20g so that the busbar 28 is prevented from detaching from the groove 20g. The groove 20g is recessed in the axial direction of the brushed motor 10. A cross-section parallel to the axial direction of the bus bar 28 is long in the axial direction.SELECTED DRAWING: Figure 5

Description

TECHNICAL FIELD The present invention relates to a motor and its manufacturing method, and more particularly to a motor having conductive busbars and its manufacturing method.

Abrasion powder and debris may be generated inside the motor due to wear or damage of internal parts. In order to realize a highly reliable motor, it is preferable to suppress such abrasion powder and debris as much as possible.

For this reason, for example, a rib is formed on the brush holder so as to cover the radial outer periphery of the sliding contact portion where the commutator attached to the rear end side outer peripheral surface of the shaft and the brush are in sliding contact, and the brush wear is induced by the rib. A motor with a brush provided with a pocket for storing powder has been proposed (see, for example, Patent Document 1). As a result, brush wear powder generated by sliding contact is prevented from diffusing by the ribs, and the brush wear powder does not diffuse inside the motor, thereby suppressing a decrease in the insulation resistance value at unspecified locations in the motor with brushes. becomes possible.

JP 2016-197930 A

Various electrically conductive members are mounted inside the motor. In recent years, some parts of motors are made of resin, and when a conductive member is attached to such a resin part by, for example, press fitting, the resin is scraped off and resin powder or fragments are left inside the motor. may remain in However, since even such resin powders and fragments can reduce the reliability of the motor, it is necessary to suppress their generation.

In order to solve the above-described problems, a motor according to the present invention includes a conductive busbar and a projecting portion made of resin and having a groove into which the busbar is inserted. It has a dissolving portion that closes the opening of the groove so as to prevent it from detaching from the groove. According to this aspect, it is possible to reduce the possibility that resin powder or fragments will scatter when attaching the bus bar. Therefore, it is possible to suppress deterioration in the reliability of the motor due to resin powder or fragments.

The groove may be recessed in the axial direction of the motor, and a cross section of the busbar parallel to the axial direction and perpendicular to the extending direction of the busbar may be long in the axial direction. According to this aspect, the area occupied by the busbar in the radial direction of the motor can be reduced. Therefore, the space inside the motor can be effectively utilized.

The motor may be a brushed motor. A brushed motor has brushes and a commutator inside. Since the brushes are pressed against the commutator, they must be arranged in the motor so as to extend radially. According to this aspect, even when there are radially extending brushes, the area occupied by the busbar in the radial direction of the motor can be reduced, so that the space inside the motor can be effectively utilized.

The motor may further include a capacitor for EMC countermeasures. The bus bar may be connected to the capacitor. According to this aspect, it is possible to reduce the area occupied by the busbar used for EMC countermeasures in the radial direction of the motor.

In order to solve the above-mentioned problems, another motor manufacturing method according to the present invention comprises the steps of: inserting a conductive bus bar into a groove formed in a protrusion made of a conductive resin; closing the opening of the groove by dissolving a portion of the protrusion so as to prevent detachment. According to this aspect, it is possible to reduce the possibility that resin powder or fragments will scatter when attaching the bus bar, so that deterioration in reliability of the motor can be suppressed.

According to the present invention, it is possible to suppress deterioration in the reliability of the motor caused by resin powder or fragments.

1 is a perspective view of a brushed motor according to an embodiment; FIG. It is a perspective view of the brush assembly which concerns on this embodiment. It is a perspective view of a bus bar concerning this embodiment. (a) is a sectional view around a boss. (b) is a top view of the boss. It is a perspective view of the brush assembly which concerns on this embodiment. FIG. 4 is a cross-sectional view of the periphery of the dissolving portion;

FIG. 1 is a perspective view of a brushed motor 10 according to this embodiment. Brushed motor 10 includes brush assembly 12 , commutator 14 , housing 16 and shaft 18 . The housing 16 is formed in a bowl shape with a cylindrical outer periphery. The brush assembly 12 is generally disk-shaped and is mounted in an opening of a housing 16 to form a cylindrical brushed motor 10 . The housing 16 is formed with an insertion hole coaxial with the central axis of the brushed motor 10, and a shaft 18 is inserted into this insertion hole. The commutator 14 is provided on the outer circumference of this shaft 18 . The brush assembly 12 also has an insertion hole coaxial with the central axis, into which the shaft 18 is inserted.

A core (not shown) is attached to the outer peripheral surface of the shaft 18, and a winding (not shown) is wound around this core. A magnet (not shown) is arranged on the inner peripheral surface of the housing 16 so as to face the core. These non-illustrated configurations of brushed motors are well known and will not be described further.

FIG. 2 is a perspective view of the brush assembly 12 according to this embodiment. The brush assembly 12 has a base member 20 , brushes 22 , brush holders 24 and springs 26 . The base member 20 is made of resin and has a base plate 20a, a flange 20b, an insertion hole 20c, and a spring stopper 20d. The base plate 20a is formed in a disc shape. The flange 20b extends from the edge of the base plate 20a in the axial direction of the brushed motor 10 (hereinafter simply referred to as "axial direction"). The insertion hole 20c is formed as a round hole coaxial with the center of the base plate 20a. The commutator 14 or the shaft 18 near the commutator 14 is inserted into the insertion hole 20c.

A brush holder 24 is attached to the base plate 20 a so as to extend toward the center of the brush assembly 12 . The spring 26 is inserted through the central opening of the brush holder 24, and then the brush 22 is inserted through the central opening of the brush holder 24 as well. Thus, the brush holder 24 accommodates the brush 22 so as to be movable toward the commutator 14 . The spring 26 is a coil spring, the tip of which contacts the rear end of the brush 22 and the rear end of which contacts the spring stopper 20d. A spring stop 20d is arranged near the flange 20b. A spring 26 biases the brush 22 housed in the brush holder 24 toward the commutator 14 .

In this embodiment, the base member 20 is configured such that up to four brush holders 24 can be attached to the brush assembly 12 . That is, the brushed motor 10 according to the present embodiment is configured so that up to four brushes 22 can be used. The brushed motor 10 according to the present embodiment is configured such that only the necessary number of brushes 22 can be attached among the four brushed motors 10 according to the required output of the brushed motor 10 . Accordingly, by using the common base member 20, brushes 22, and brush holders 24, the brushed motors 10 with various outputs can be manufactured. FIG. 2 shows an example in which four brushes 22 and brush holders 24 are provided.

The base member 20 further has bosses 20e and bank portions 20f. Boss 20e is then melted as described below. FIG. 2 shows the state before the boss 20e is melted. The base member 20 is made of resin, and the base plate 20a, flange 20b, spring stopper 20d, boss 20e, and bank portion 20f are integrally formed. Therefore, the flange 20b, bank portion 20f, and boss 20e are made of resin. The bank portion 20f is raised from the base plate 20a along the flange 20b so as to have substantially the same height as the flange 20b.

The boss 20e is a projecting portion axially projecting from the bank portion 20f and the flange 20b, and is formed in a cylindrical shape in this embodiment. Note that the boss 20e is not limited to a columnar shape, and may be formed in a square columnar shape, for example. In this embodiment, one boss 20e is arranged on each side of the spring stopper 20d in the circumferential direction. It goes without saying that the location and number of bosses 20e are not limited to this.

A groove 20g is provided between the flange 20b and the bank portion 20f. This groove 20g continues to the boss 20e, and the groove 20g roughly bisects the boss 20e in a plane containing its center. A bus bar 28 is inserted into this groove 20g. The groove 20g is recessed in the axial direction of the motor. When viewed from the axial direction, the groove 20g is composed of a plurality of straight lines intersecting at moderate angles along the outer peripheral surface of the flange 20b. Note that the groove 20g may be formed in an arc shape along the outer peripheral surface of the flange 20b.

FIG. 3 is a perspective view of the busbar 28 according to this embodiment. The bus bar 28 is made of a conductive metal plate. The busbar 28 has an extension portion 28a and an exposed portion 28b. The extension part 28a is elongated at a constant height. The extending portion 28a is composed of a plurality of linear portions that intersect at moderate angles when viewed from the axial direction so as to match the shape of the groove 20g. Note that the extension portion 28a may be formed in an arc shape when viewed from the axial direction.

The exposed portions 28b are provided at both ends of the extension portion 28a. The exposed portion 28b is formed by bending at an acute angle from the extending portion 28a toward the inside of the base member 20 . The exposed portion 28b has a protruding portion 28c that protrudes upward. A concave portion 28d that is recessed downward is formed in the projecting portion 28c. A conducting wire is arranged in this concave portion 28d.

FIG. 4(a) is a sectional view around the boss 20e. As shown in FIG. 4A, the groove 20g is formed between the flange 20b and the bank portion 20f so as to divide the boss 20e into two. An extending portion 28a of a conductive bus bar 28 is inserted into this groove 20g. At this time, the cross section of the busbar 28 parallel to the axial direction and perpendicular to the extending direction of the busbar 28 is elongated in the axial direction. By arranging the bus bar 28 to be long in the axial direction and short in the radial direction in this manner, the space inside the motor can be effectively utilized. In particular, brushed motor 10 has brushes 22 and commutator 14 therein. Since the brushes 22 are pressed against the commutator 14, the brushes 22 must be arranged in the brushed motor 10 so as to extend radially. By arranging the busbars 28 to be long in the axial direction and short in the radial direction in this way, it is possible to reduce the area occupied by the busbars 28 in the radial direction even when there are brushes 22 extending in the radial direction. The space inside the brushed motor 10 can be effectively utilized.

The brush assembly 12 has a capacitor 30 for EMC countermeasures. The busbar 28 is connected to this capacitor 30 . Note that the bus bar 28 may be used to connect components other than the capacitor 30 .

FIG. 4(b) is a top view of the boss 20e. The boss 20e according to this embodiment has a crush rib 20h. The crush rib 20h extends in the axial direction inside the groove 20g passing through the boss 20e so as to swell from both walls of the groove 20g toward the center of the boss 20e. By providing the crush rib 20h, the bus bar 28 can be firmly gripped. Note that the crush rib 20h may not be provided.

FIG. 5 is a perspective view of the brush assembly 12 according to this embodiment. After the busbar 28 is inserted into the groove 20g, a part of the boss 20e is melted to block the opening of the groove 20g so as to prevent the busbar 28 from leaving the groove 20g. FIG. 5 shows a state in which the boss 20e is melted to form the melted portion 20i. In this embodiment, the tip of the boss 20e is melted by an ultrasonic welding technique so that the opening of the groove 20g is closed. The dissolved portion 20i thus formed closes the opening of the groove 20g so as to prevent the bus bar 28 from being detached from the groove 20g.

Note that the tip of the boss 20e may be melted to form the melted portion 20i by a technique other than the ultrasonic welding technique. In this embodiment, the dissolving portion 20i is formed in a dome shape, but the shape of the dissolving portion 20i is of course not limited to this.

By dissolving the tip of the boss 20e to prevent the busbar 28 from being detached in this way, it is possible to greatly reduce resin powder and fragments that may scatter as compared with, for example, the case where the busbar 28 is press-fitted into the resin. . Therefore, it is possible to suppress deterioration in the reliability of the motor caused by resin powder or fragments.

Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above-described embodiments, and the present invention also includes appropriate combinations and replacements of the configurations of the embodiments. It is a thing. Further, it is also possible to appropriately rearrange the combinations and the order of processing in the embodiments based on the knowledge of those skilled in the art, and to add modifications such as various design changes to the embodiments. Embodiments may also fall within the scope of the invention.

In one variation, a motor that is not a brushed motor includes a busbar that is electrically conductive and a boss that is a protrusion made of resin that has a groove into which the busbar is inserted. The boss has a melted portion that closes the opening of the groove to prevent the busbar from leaving the groove. For example, in brushless motors, busbars may be used to connect the coils, and the busbars may be mounted in this manner. In this case as well, the space inside the motor can be effectively utilized while suppressing the generation of resin powder and fragments.

10 brushed motor, 12 brush assembly, 14 commutator, 16 housing, 20 base member, 20a base plate, 20b flange, 20c insertion hole, 20d spring stopper, 20e boss, 20f bank portion, 20g groove, 20h crush rib, 20i melting portion , 22 brush, 24 brush holder, 26 spring, 28 bus bar, 28 a extending portion, 28 b exposed portion, 28 c projecting portion, 28 d concave portion, 30 capacitor

Claims (5)

a conductive busbar;
a projecting portion made of resin and having a groove into which the busbar is inserted;
with
The motor according to claim 1, wherein the projecting portion has a dissolving portion that closes an opening of the groove so as to prevent the bus bar from being separated from the groove. The groove is recessed in the axial direction of the motor,
2. The motor according to claim 1, wherein a cross section of said bus bar parallel to said axial direction and perpendicular to an extending direction of said bus bar is long in said axial direction. 3. A motor according to claim 1, wherein said motor is a brushed motor. The motor further includes a capacitor for EMC countermeasures,
4. The motor according to claim 1, wherein said bus bar is connected to said capacitor. a step of inserting a conductive busbar into a groove formed in the projecting portion made of resin;
a step of dissolving a portion of the protruding portion to block the opening of the groove so as to prevent the bus bar from being detached from the groove;
A method of manufacturing a motor, comprising:

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