JP5434817B2 - Commutator motor - Google Patents

Description

  The present invention relates to a commutator motor including a varistor for preventing electromagnetic noise generated when a commutator and a brush slide.

For example, there is a small commutator motor used as a driving actuator such as a variable intake valve or TGV (tumble generator valve) of an automobile. In this commutator motor, sparks are generated by the high voltage induced by the intermittent connection between the commutator and the brush when the armature rotates, causing brush consumption and noise. As a countermeasure, a technique for connecting a varistor (nonlinear resistance element) to a commutator segment is known.
For example, in Patent Document 1, as shown in FIG. 5, a varistor receiving portion 130 is integrally provided on a riser portion 120 of a segment 110 that forms a connection portion with a coil wire 100, and a ring varistor 140 is provided on the varistor receiving portion 130. A structure in which soldering is performed while soldering is held is disclosed.

JP 2001-298910 A

  In the conventional varistor structure disclosed in Patent Document 1 described above, it is possible to hold the downward force in the figure applied to the solder joint 150 via the ring varistor 140 by the varistor receiving part 130. However, the force applied to the solder joint 150 in the radial direction of the commutator via the ring varistor 140 (the left-right direction in the figure) cannot be held by the varistor receiving part 130. For this reason, if the strength of the solder joint 150 is not sufficiently ensured due to the quality of the solder or the like, the solder joint 150 may be damaged due to the centrifugal force acting on the solder joint 150 when the armature rotates. .

  In the varistor holding structure shown in FIG. 5, the difference between the inner diameter of the ring varistor 140 and the outer diameter of the varistor receiving part 130 is small. In other words, the contact area between the varistor receiving part 130 and the ring varistor 140 is small. When the solder joint 150 is broken, the ring varistor 140 may fall off the varistor receiving part 130 even if the ring varistor 140 is slightly displaced in the radial direction. If the ring varistor 140 falls off the varistor receiving part 130 during the rotation of the armature, there arises a problem that the coil wire 100 is disconnected due to the ring varistor 140 rubbing against the coil end 160 of the armature coil.

  The present invention has been made based on the above circumstances, and its purpose is to provide a commutator motor in which a varistor is joined by soldering to a terminal part provided in a riser part of a segment. An object of the present invention is to provide a varistor holding structure capable of avoiding breakage of a solder joint by preventing stress applied and preventing the varistor from dropping from a terminal part.

(Invention of Claim 1)
In the present invention, a predetermined number of segments arranged in a cylindrical shape with a constant interval in the circumferential direction are integrally held by a resin molded body, and this resin molded body is placed on the outer periphery of the rear end portion of the armature shaft. Prevents electromagnetic noise from being generated due to an armature provided with a commutator that is fitted and attached, and a commutation spark generated when the brush slides on the outer peripheral surface of the commutator when the armature rotates. The segment has a riser portion that forms a connection portion with the armature coil, and the riser portion has a radially outer side perpendicular to the axial direction of the commutator. And a terminal portion is bent at the radially outer end toward the rear end of the armature shaft to form a centrifugal force receiving portion, and the varistor is a commutator. Ring shape with a gap on the outer periphery It is provided, arranged radially inside the centrifugal force receiving portion with the radial outer periphery held by the centrifugal force receiving portion, and electrically and mechanically joined to the surface of the terminal portion by soldering. It is characterized by.

According to the above configuration, even if the centrifugal force generated when the armature rotates acts on the solder joint, the radial outer periphery of the varistor joined to the terminal portion at the solder joint is held in the centrifugal force receiver. Therefore, the stress applied to the solder joint can be relaxed. As a result, the margin of strength of the solder joint can be improved, and the solder joint can be prevented from being damaged by the action of centrifugal force.
Moreover, since the outer periphery in the radial direction of the varistor is held by the centrifugal force receiving portion, even if the solder joint is damaged, the varistor does not shift in the radial direction. The coil wire cannot be disconnected due to the drop of the varistor.

(Invention of Claim 2)
2. The commutator motor according to claim 1, wherein the centrifugal force receiving portion is formed by bending an end portion on the radially outer side of the terminal portion into an L shape toward the rear end direction of the electromagnetic shaft, and the varistor has a radially outer periphery. Is held in the centrifugal force receiving portion while being press-fitted into the inner periphery of the centrifugal force receiving portion.
In the invention according to claim 2, since the outer circumference in the radial direction of the varistor is press-fitted into the inner circumference of the centrifugal force receiving portion, the varistor can be held by pressure input even if the solder joint is broken. Will not drop and the coil wire will not break.
The centrifugal force receiver also functions as a guide when assembling the varistor, so the varistor can be concentric with the armature shaft by press-fitting the radial outer periphery of the varistor into the inner periphery of the centrifugal force receiver. Can be placed. In other words, the center of the varistor can be aligned with the center of the armature shaft without using a positioning jig or the like, and the radial eccentricity of the varistor with respect to the armature shaft can be suppressed. Can be stabilized.

(Invention of Claim 3)
3. The commutator motor according to claim 1, wherein an opening hole penetrating in the thickness direction is formed in the terminal portion, and the varistor is soldered to the terminal portion from the side opposite to the varistor in the thickness direction through the opening hole. It is characterized by being attached.
By forming the opening hole in the terminal portion, the bonding area of the varistor can be increased according to the size (opening area) of the opening hole, so that sufficient bonding strength can be ensured.

(Invention of Claim 4)
The commutator motor according to any one of claims 1 to 3, wherein a distal end portion of the centrifugal force receiving portion is bent toward the varistor side and the outer peripheral portion of the varistor is caulked and fixed.
According to this configuration, by caulking and fixing the outer peripheral portion of the varistor, the stress applied to the solder joint during rotation of the armature can be greatly relieved, so that a more reliable varistor holding structure can be provided.

3 is a half cross-sectional view of a commutator showing a varistor holding structure according to Embodiment 1. FIG. It is AA sectional drawing of FIG. 1 which shows a solder joint part. It is sectional drawing which shows the modification of a solder joint part. 6 is a half sectional view of a commutator showing a varistor holding structure according to Embodiment 2. FIG. It is a half section view of a commutator which shows a holding structure of a varistor concerning the prior art.

  The mode for carrying out the present invention will be described in detail with reference to the following examples.

Example 1
The electric motor shown in the first embodiment is a small DC motor used as a driving actuator such as a variable intake valve or a TGV of an automobile, for example, and as shown in FIG. Electromagnetic noise due to an armature having a commutator 2 on the outer periphery of the upper end portion and commutation sparks generated when a brush (not shown) slides on the outer peripheral surface of the commutator 2 when the armature rotates. Is provided with a varistor 3 for preventing the occurrence of.
The commutator 2 includes a predetermined number of segments 20 arranged at equal intervals in the circumferential direction, and a cylindrical resin molded body 21 that integrally holds the predetermined number of segments 20. 21 is press-fitted and attached to the outer periphery of the rear end portion of the armature shaft 1.

Each segment 20 has a predetermined length along the axial direction (the vertical direction in the drawing) of the armature shaft 1 and forms a connection portion with the armature coil on one end side (the lower side in the drawing) in the longitudinal direction. The riser portion 20a is integrally provided. The riser portion 20a is folded back from the end portion on one end side of the segment 20 toward the rear end direction (upward direction in the drawing) of the armature shaft 1 and the end portion of the coil wire 4a drawn out from the coil end 4 of the armature coil. The coil wire 4a is electrically and mechanically connected, for example, by fusing (heat caulking).
The riser portion 20a is provided with a terminal portion 20b for attaching the varistor 3. The terminal portion 20b extends in a plate shape from the distal end portion of the riser portion 20a to the radially outer side of the commutator 2 perpendicular to the longitudinal direction of the segment 20, and the end portion on the radially outer side is the armature shaft 1. The centrifugal force receiving portion 20c is formed by being bent in an L shape toward the rear end. Hereinafter, the upper surface in the thickness direction of the terminal portion 20b shown in FIG. 1, that is, the surface in the direction in which the centrifugal force receiving portion 20c is formed is called a varistor receiving surface, and the lower surface in the drawing is an anti-varistor receiving surface. Call it.

The varistor 3 has a ring shape in which a round hole 3a (see FIG. 1) is opened at the center in the radial direction, and an electrode portion (not shown) for the terminal portion 20b is formed on one surface in the plate thickness direction. Yes. The inner diameter of the round hole 3a is formed larger than the outer diameter of the commutator 2, and the outer diameter of the varistor 3 is the same as the diameter of the inscribed circle in contact with the inner peripheral surface of the centrifugal force receiving portion 20c provided in each terminal portion 20b. Have dimensions.
The varistor 3 is assembled from the rear end side of the armature shaft 1 to the inside of the round hole 3a through the outer periphery of the commutator 2, and the radial outer periphery of the varistor 3 is press-fitted into the inner periphery of the centrifugal force receiving portion 20c. The one side of the varistor 3 disposed on the radial inside of the centrifugal force receiving part 20c and having the electrode part formed thereon is superposed on the varistor receiving surface of the terminal part 20b, and is electrically and mechanically connected to the terminal part 20b by soldering. Are joined together.

For example, as shown in FIG. 2, the terminal portion 20b is formed with an opening hole 20d penetrating in the plate thickness direction (direction orthogonal to the paper surface), and through the opening hole 20d from the side opposite to the varistor receiving surface of the terminal portion 20b. Soldering can be performed. That is, the molten solder is poured from the anti-varistor receiving surface side of the terminal portion 20b to the varistor receiving surface side through the opening 20d, whereby the varistor 3 and the terminal portion 20b arranged on the varistor receiving surface side of the terminal portion 20b are illustrated. It is possible to join firmly by the solder joint part 5 shown with a dashed-two dotted line inside.
In FIG. 2, the rectangular opening hole 20 d is shown, but any shape that can sufficiently secure the bonding area of the varistor 3 may be used, and the shape of the opening hole 20 d need not be limited to a rectangle. It is also possible to form two or more openings 20d. Further, without forming the opening hole 20d in the terminal portion 20b, for example, as shown by a two-dot chain line in FIG. 3, the solder joint portion 5 can be provided along both sides of the terminal portion 20b.

(Operation and Effect of Example 1)
According to the varistor holding structure of this embodiment, even if the centrifugal force generated when the armature rotates acts on the solder joint portion 5 between the varistor 3 and the terminal portion 20b, the radial outer periphery of the varistor 3 is the centrifugal force receiving portion. Since it is hold | maintained at 20c, the stress concerning the solder joint part 5 can be relieved. As a result, the margin of strength of the solder joint portion 5 can be improved, and damage to the solder joint portion 5 due to the action of centrifugal force can be avoided. In particular, in Example 1, since the outer periphery in the radial direction of the varistor 3 is held in a state where it is press-fitted into the inner periphery of the centrifugal force receiving portion 20c, even if the solder joint portion 5 is damaged, the varistor 3 is pressed by pressure input. Can be held. Thereby, even when the joining strength of the solder joint portion 5 is not sufficient, or even when the solder joint portion 5 is broken, the varistor 3 does not shift in the radial direction with respect to the terminal portion 20b. Furthermore, since it is impossible for the varistor 3 to get over the centrifugal force receiving portion 20c and fall off to the coil end 4 side (downward in FIG. 1), the varistor 3 is rubbed against the coil wire 4a and the coil wire 4a is disconnected. In addition, a highly reliable varistor holding structure can be provided.

  Moreover, in the varistor holding structure of the present embodiment, the centrifugal force receiving portion 20c is assembled with the centrifugal force receiving portion 20c because the end portion on the radially outer side of the terminal portion 20b is bent into an L shape to form the centrifugal force receiving portion 20c. The varistor 3 also functions as a guide at the time, and as described above, the radial outer periphery of the varistor 3 is press-fitted into the inner periphery of the centrifugal force receiving portion 20c and assembled. Can be adjusted to the center of That is, since the varistor 3 can be arranged concentrically with the armature shaft 1 without using a positioning jig or the like, radial eccentricity of the varistor 3 with respect to the armature shaft 1 can be suppressed, and the rotation balance of the armature. The effect which can stabilize can also be expected. Furthermore, since the opening 20d for soldering is formed in the terminal portion 20b, the bonding area of the varistor 3 can be increased according to the size (opening area) of the opening 20d. Sufficient bonding strength can be secured.

(Example 2)
As shown in FIG. 4, the second embodiment is an example in which the distal end portion of the centrifugal force receiving portion 20c is bent toward the varistor 3, and the outer peripheral portion of the varistor 3 is caulked and fixed.
According to this configuration, by caulking and fixing the outer peripheral portion of the varistor 3, the stress applied to the solder joint portion 5 during the rotation of the armature can be greatly relieved, so that the margin of strength of the solder joint portion 5 can be further improved. . Even if the solder joint 5 is damaged, the varistor 3 does not fall over the centrifugal force receiving portion 20c to the coil end 4 side as in the first embodiment, and the outer periphery of the varistor 3 Therefore, the varistor 3 does not fall off from the centrifugal force receiving portion 20c toward the rear end of the armature shaft 1 (upward in FIG. 4). Thereby, since the varistor 3 is not detached from the terminal portion 20b and is not blown off when the armature is rotated, the reliability can be improved and high compared with the conventional varistor holding structure described in Patent Document 1. Safety can be secured.

(Modification)
The centrifugal force receiving portion 20c described in the first embodiment is formed by bending the radially outer end of the terminal portion 20b into an L shape. However, the centrifugal force receiving portion 20c does not necessarily need to be bent into an L shape, and the varistor 3 has a radial direction. Any shape that can hold the outer periphery may be used.
Moreover, in Example 1, although the example which press-fits the outer periphery of the radial direction of the varistor 3 to the inner periphery of the centrifugal force receiving part 20c was described, the outer periphery of the radial direction of the varistor 3 and the inner periphery of the centrifugal force receiving part 20c were described. There may be some gaps between them. That is, it is only necessary that the radial outer periphery of the varistor 3 can be held by the centrifugal force receiving portion 20c, and a configuration in which the radial outer periphery of the varistor 3 is fitted into the inner periphery of the centrifugal force receiving portion 20c is possible.

1 Armature shaft 2 Commutator 3 Varistor (ring varistor)
4a Coil wire 5 Solder joint part 20 Segment 20a Riser part 20b Terminal part 20c Centrifugal force receiving part 20d Opening hole formed in terminal part 21 Resin molding

Claims (4)

A predetermined number of segments arranged in a cylindrical shape with a certain interval in the circumferential direction are integrally held by a resin molded body, and this resin molded body is fitted to the outer periphery of the rear end portion of the armature shaft. An armature with a commutator to be attached;
A commutator motor having a varistor for preventing electromagnetic noise from being generated due to commutation sparks generated when a brush slides on the outer peripheral surface of the commutator during rotation of the armature,
The segment has a riser portion that forms a connection portion with an armature coil, and the riser portion is provided with a plate-like terminal portion that extends outward in the radial direction perpendicular to the axial direction of the commutator. And the terminal portion has a radially outer end bent to the rear end direction of the armature shaft to form a centrifugal force receiving portion,
The varistor is provided in a ring shape that fits with a gap around the outer periphery of the commutator, and the radially outer periphery is held radially inward of the centrifugal force receiving portion while being held by the centrifugal force receiving portion. The commutator motor is arranged and electrically and mechanically joined to the surface of the terminal portion by soldering. In the commutator motor according to claim 1,
The centrifugal force receiving portion is formed by bending an end portion on the radially outer side of the terminal portion into an L shape toward the rear end direction of the electromagnetic shaft,
The ring varistor is held by the centrifugal force receiving portion in a state in which a radially outer periphery is press-fitted into an inner periphery of the centrifugal force receiving portion. In the commutator motor according to claim 1 or 2,
In the terminal portion, an opening hole penetrating in the plate thickness direction is formed,
The ring varistor is soldered to the terminal portion through the opening hole from the side opposite the varistor in the plate thickness direction. The commutator motor according to any one of claims 1 to 3,
A commutator motor, wherein a distal end portion of the centrifugal force receiving portion is bent toward the ring varistor, and an outer peripheral portion of the ring varistor is caulked and fixed.

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