JP5203011B2 - Commutator member for motor and motor - Google Patents

Description

  The present invention relates to a motor used in audio equipment, video equipment, precision equipment, automotive electrical equipment, and the like. In particular, the commutator can be easily manufactured, and the commutator piece and a conductor are joined. The present invention relates to a commutator member for motors that has excellent so-called spot bonding strength and high bonding reliability.

The connection between each conventional commutator piece and the winding coil end will be described with reference to the drawings.
FIG. 4 is a schematic perspective view of the commutator portion of the small motor. In the figure, 11 is a rotor shaft, 12 is a commutator core, 13 is a commutator piece, and 14 is a commutator foot. In this way, the commutator part is integrally formed with each commutator piece 13 to connect each commutator piece 13 disposed on the resin commutator core 12 and the winding coil end. The commutator foot portion 14 is formed.
FIG. 5 is a side view seen from the side of the commutator portion shown in FIG. 4 and shows a state in which the winding coil ends are joined. The commutator foot 14 is spot-welded by pressing the end of the winding coil 15 by bending it toward the commutator piece as shown.

  FIG. 6 is a view showing only a varistor extracted in (b) and a state in which the varistor is attached and connected to the commutator section in (a). In a small motor having a commutator, an arc is generated when the brush that is in sliding contact with the commutator passes between the commutator pieces, and this arc can cause radio interference in communication equipment and shorten the life of the brush. To do. For this reason, it is conventionally known that a varistor is attached to a rotor of a motor as a spark erasing element. An example of such a varistor has a shape as shown in FIG. 6 (b), has a donut-like disk shape as a whole, and has the same number of electrodes as the number of rotor magnetic poles, that is, commutator pieces. Yes. Each electrode 17 of the varistor 16 is soldered to each commutator foot 14. By this soldering, the varistor 16 is not only electrically connected but also mechanically fixed concentrically with the commutator portion.

A wire as a conductive material used for an electronic component such as a winding coil of such a small motor is usually coated with an insulating material such as polyurethane or polyester to form an insulating film. The end of the winding coil of a small motor must be electrically and mechanically joined to each commutator foot. As a technique, fine irregularities (so-called star hits) are formed on the folded inner surface of the commutator foot. : A fine star-shaped concave portion is provided), and the film is peeled off and bonded by applying a heat shock by spot welding.
FIG. 7 is a cross-sectional view showing a state in which winding coil end portions are joined when a motor commutator material is used. Inside the bent part of the commutator foot 14, solder plating or plating with a low melting point such as Sn or a clad material is supported in advance to hold the winding coil 15, thereby softening the disconnection due to heat shock and performing bonding. ing.

As an example of the commutator piece material formed by the prior art, for example, in Patent Document 1, the melting point of the commutator piece that joins the copper-based commutator piece and the conductive wire is larger than that of the base material. The purpose is to simplify the work process by using a thin clad material with a low electrical resistance and a high electrical resistance, eliminating the need for star-casting and solder plating processes.
On the other hand, in Patent Document 2, Ni or Co or an alloy thereof is formed on a conductive substrate as a first layer, an Ag-based coating layer as a second layer, and an Sn-based metal layer at a junction between a commutator piece and a conductive wire. Some have achieved bonding stability by plating.
JP 2003-061314 A JP 2006-149144 A

However, in the method of improving with the clad material described in Patent Document 1, solder plating can be omitted, but the clad has a limit to thinning. Further, the surface property of the clad material is more serious than the plating, and there is a concern that even if spot bonding is performed using the clad material, there is a possibility that the bonding reliability may be lost due to surface contamination.
Further, in the technique of Patent Document 2, it is specified that a base layer for preventing diffusion of either Ni-based or Co-based is provided. It has been found that when the thickness of the wire is formed to exceed 0.1 μm, the bonding strength between the commutator piece and the conductive wire is decreased, and the variation in bonding strength is increased.
Accordingly, an object of the present invention is to provide a commutator member for a motor that has high joint strength between a commutator piece and a conductor, can reduce variations in the strength, and has excellent stable and reliable spot joint strength, and the same. It is to provide a motor.

The inventor examined the joint between the commutator piece and the conductive wire in view of the above problems, and when the undercoat provided as an intermediate layer between the Cu base and the Sn layer is formed to exceed 0.1 μm, It was ascertained that Cu became difficult to diffuse into Sn due to the barrier effect of the base component due to the intermediate layer, causing breakage in the Sn layer, and the strength of the spot bonding being lowered due to its low strength.
In addition, a method of growing a Cu-Sn diffusion layer by applying Sn plating without applying an undercoat was also examined. However, Ag or Ag alloy plating or cladding conventionally used for sliding contact portions without an intermediate layer When processed, it was found that the discoloration of the Ag sliding contact portion after the formation of Ag becomes conspicuous due to the diffusion of Cu, and the contact resistance increases and the motor characteristics are likely to be impaired. Furthermore, it was found that the Cu—Sn diffusion layer was completely formed in the spot welded portion, resulting in low joint strength stability and reliability.
For this reason, in order to keep the spot bonding strength stable and high, it was considered that proper growth of the Cu—Sn diffusion layer and the remaining of the Sn layer are important.

That is, the present invention
(1) A motor commutator member in which a coating made of Sn or Sn alloy is formed on a joint made of Cu or Cu alloy on a base made of Cu or Cu alloy, and the base made of Cu or Cu alloy and Sn Alternatively, a commutator for a motor, wherein Ni or Ni alloy or Co or Co alloy is provided as an intermediate layer in the middle of a film made of Sn alloy, and the intermediate layer thickness is 0.01 to 0.05 μm. Element,
(2) The commutator member for a motor according to (1), wherein the intermediate layer formed on the substrate and the film made of Sn or Sn alloy are formed by a plating method,
(3) The motor commutator member according to (1) or (2), wherein the formed film of Sn or Sn alloy is subjected to a melting treatment, and
(4) A motor equipped with the motor commutator member according to any one of (1) to (3),
Is to provide.

The commutator member for a motor of the present invention has a higher bonding strength between a commutator piece and a conductive wire than that of the prior art, and can reduce the variation thereof, and is excellent for a stable and reliable spot bonding strength. A commutator member. In addition, since the intermediate barrier layer is present, good motor life characteristics can be obtained even on the sliding contact surface of the commutator, and a commutator member that satisfies the required motor characteristics such as low contact resistance can be obtained.
Further, by using a plating method for forming the intermediate layer and the Sn coating, it is possible to manufacture at a lower cost and with a shorter lead time than the clad material.
Further, by melting the film made of Sn or Sn alloy, the formation of the diffusion layer can be further promoted, the risk of the generation of whiskers (whiskers) can be reduced, and the commutator piece It is possible to suppress the powder falling off when punching into the mold.

A preferred embodiment of the commutator member for a motor of the present invention will be described in detail below.
A commutator member used in the motor commutator of the present invention is schematically shown in a sectional view in FIG. A substrate made of Cu or a Cu alloy is used as the substrate 1 of the commutator member. Examples of the substrate include alloys containing Cu as a main component, such as Cu—Sn, Cu—Zn, and Cu—Sn—P, in addition to pure Cu. The thickness of the substrate to be used is not particularly specified, but a practical thickness is about 0.1 to 0.5 mm.

  The film 3 made of Sn or Sn alloy in FIG. 1 formed on the surface of the substrate made of Cu or Cu alloy includes, for example, pure Sn, Sn—Pb, Sn—Zn, Sn—Cu, Sn— Bi-based, Sn-In-based, Sn-Ag-based, Sn-Pd-based, Sn-Ni-based, and other ternary alloys such as Sn-Ag-Cu are included. The coating thickness to be formed is not particularly specified. For example, a thickness of 0.5 to 10 μm is preferable, and considering the improvement of connection reliability, prevention of powder falling off during pressing, and economic efficiency, 1.0 to It is particularly preferable to form in the range of 6.0 μm.

As shown in FIG. 1, Ni or Ni alloy or Co or Co alloy formed as the intermediate layer 2 between the two layers includes, for example, pure Ni, Ni—Co, Ni—Zn, Ni—Sn, Ni— There are Ni-Fe, Ni-P, Ni-B, and the like, and Co-based materials include pure Co, Co-Ni, Co-Zn, Co-Sn, Co-Fe, Co-P, and Co-B.
It is necessary to control the coating thickness of the intermediate layer 2 to be formed in the range of 0.01 to 0.05 μm. If the thickness is too thin , the Cu—Sn diffusion layer is formed as a whole, resulting in a decrease in bonding strength and variation due to the embrittlement of the intermetallic compound, and conversely, if the coating thickness is too thick. In addition, since the diffusion of the substrate is suppressed too much by the intermediate layer, if the spot bonded portion is broken, it will be broken in the Sn or Sn alloy layer, and the spot bonded strength is lowered because the tensile strength of Sn is weak. End up.

It is necessary to control the thickness of the intermediate layer to 0.01 to 0.05 μm. This is achieved by appropriately diffusing Cu of the base material into the Sn from the pinhole of the intermediate layer, so that moderate Cu− Both requirements of Sn diffusion layer and remaining Sn layer can be satisfied.
As a result, it is possible to produce a commutator material for a motor that can maintain high spot-bonding strength, prevent discoloration due to the slight presence of an intermediate layer, and satisfy required motor characteristics such as low contact resistance.
Particularly in the motor characteristic and the spot bonding strength both that obtained sufficiently satisfactory characteristics range of the coating thickness of the intermediate layer is set to 0.01 to 0.05 [mu] m.
In addition, 4 in the figure is a commutator sliding contact portion, and is not a joint portion with the winding coil. Therefore, the layer does not need to be Sn or Sn alloy, and stripe-shaped Au, Pd, Ag or These alloy layers. This layer thickness is not particularly limited, and is about 0.1 to 10 μm. The same applies to FIGS. 2 and 3 below.

FIG. 2 is a cross-sectional view schematically showing a commutator member used in a motor commutator according to another embodiment of the present invention. As shown in FIG. The effect of the present invention is exhibited when the coating layer thickness is 0.01 to 0.05 μm in total.
FIG. 3 is a cross-sectional view schematically showing a motor commutator member according to still another embodiment of the present invention. Thus, it is sufficient that the thickness of the intermediate layer 2 at the location of the coating 3 made of Sn or Sn alloy formed at the junction with the winding coil is in the range of 0.01 to 0.05 μm. The intermediate layer thickness other than the joint is not limited to the above range.

  The intermediate layer and the Sn layer are preferably formed by a plating method because it is easy to adjust the thickness and to be formed uniformly and to form an oxide film and air pollution as much as possible. Examples of the plating method include hot-dip plating, electroplating, electroless plating, etc. In consideration of film thickness controllability, production lead time, manufacturing cost, ease of production, etc., the most preferable method is electroplating. preferable. If the electroplating method is used, the degree of variation in the coating thickness can be reduced, and since the surface contamination is small, the motor characteristics such as low contact resistance are good, and particularly a reliable commutator piece with stable spot bonding strength. Can be manufactured.

Of course, the Sn layer on the outermost surface can be press-molded into the commutator member while the layer is still formed, but it is also effective to perform a melting treatment after forming the Sn layer. By performing the melting treatment, it is possible to reduce the risk of generation of a whisker-like product (whisker) that is likely to appear from the Sn film, and there is an effect of suppressing powder falling during pressing.
By using the commutator material formed in this way for a motor, it is possible to provide a motor with high spot junction strength and high reliability without impairing motor characteristics.

The present invention will be described in more detail based on examples and the like, but the present invention is not limited thereto.
[Examples 1 to 12 and Comparative Examples 1 to 4]
In a line for continuously plating the strip material, a copper based alloy strip of CDA alloy standard C14410 having a thickness of 0.3 mm and a width of 21 mm as a base plate was passed through, and pretreatment for electrolytic degreasing and pickling was performed. Then, the plating shown in Table 1 was performed to obtain commutator materials for motors of Examples and Comparative Examples.
As a melting method of the Sn layer, a gas in which LPG is mixed at a flow rate of 0.3 l / min. And air at a flow rate of 6 l / min. Is burned with a burner, and the Sn layer is melted in an inert gas atmosphere. Solidified in water at 0 ° C.
As for the conventional example, a commutator material for motors was obtained in which Sn was formed on the substrate by the clad method.

The above material was pressed into a commutator member for a motor, and the commutator member and the enamel-coated conductive wire were spot-bonded under the following conditions.
[Spot welding conditions]
Load at first pressurization: 95N
Load during second pressurization: 9.8N
Spot bonding heating amount: 0.65 kW

Regarding the bonding strength, the bonding strength of each example, comparative example and conventional example was measured five times by the method described in JIS Z3136, and the measurement results (average strength) and the standard deviation which is an index of variation were combined. It is shown in Table 1.
Here, the spot strength that can be practically used as a motor commutator member is 0.15 MPa or more, and the evaluation is (practical level) having a value of (joining strength-standard deviation) of 0.15 or more.

The plating solution composition and plating conditions for each plating used are shown below.
[Ni plating]
Plating solution: NiSO ₄ 240 g / l, NiCl ₂ 45 g / l, H ₃ BO ₃ 30 g / l
Plating conditions: current density 5 A / dm ² , temperature 50 ° C.
[Co plating]
Plating solution: CoSO ₄ 400 g / l, NaCl 20 g / l, H ₃ BO ₃ 40 g / l
Plating conditions: current density 5 A / dm ² , temperature 30 ° C.

[Sn plating]
Plating solution: SnSO ₄ 80 g / l, H ₂ SO ₄ 80 g / l, additive 513Y (trade name, manufactured by Ishihara Pharmaceutical Co., Ltd.) 30 ml / l
Plating conditions: current density 2 A / dm ² , temperature 40 ° C.
[Glossy Sn plating]
Plating solution: SnSO ₄ 40 g / l, H ₂ SO ₄ 100 g / l, additive 513Y (trade name, manufactured by Ishihara Pharmaceutical Co., Ltd.) 30 ml / l
Plating conditions: current density 2 A / dm ² , temperature 20 ° C.

According to Table 1, it can be seen that when the Ni base plating thickness is in the range of 0.01 to 0.05 μm, the spot bonding strength of the commutator is large, the variation is small, and the bonding strength is stable.
On the other hand, if the base plating thickness is too thin or too thick , the bonding strength is small or the degree of variation is large, and it can be determined that the practical level of 1.5 kg is not stably exceeded. Further, in the conventional example, although the bonding strength is sufficiently ensured, the degree of variation is large and the bonding reliability is applied.
As a result, it can be seen that the embodiment of the present invention provides a highly reliable commutator material having excellent spot bonding strength.

FIG. 1 is a cross-sectional view schematically showing a motor commutator member according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing a commutator member for a motor according to another embodiment of the present invention. FIG. 3 is a cross-sectional view schematically showing a commutator member for a motor according to still another embodiment of the present invention. FIG. 4 is a schematic perspective view of the commutator portion of the small motor. FIG. 5 is a side view seen from the side of the commutator portion shown in FIG. 4 and shows a state in which the winding coil ends are joined. FIG. 6A is a side view of the commutator portion to which the varistor is attached, and FIG. 6B is a perspective view of only the varistor. FIG. 7 is a cross-sectional view showing a state in which winding coil end portions are joined.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Intermediate layer 3 Sn or Sn alloy film 4 Commutator sliding contact portion 5 Second layer intermediate layer 11 Shaft 12 Commutator core 13 Commutator piece 14 Commutator foot 15 Winding coil end 16 Varistor 17 Electrode

Claims (4)

A commutator member for a motor in which a coating made of Sn or Sn alloy is formed on a joint made with Cu or Cu alloy on a base made of Cu or Cu alloy, and the base made of Cu or Cu alloy and Sn or Sn alloy A motor commutator member, wherein Ni or a Ni alloy or Co or a Co alloy is provided as an intermediate layer in the middle of a film made of a material, and the intermediate layer thickness is 0.01 to 0.05 μm.
  2. The commutator member for a motor according to claim 1, wherein the intermediate layer formed on the substrate and the film made of Sn or Sn alloy are formed by a plating method.   The commutator member for a motor according to claim 1 or 2, wherein the film made of Sn or an Sn alloy is melt-treated.   The motor carrying the commutator member for motors of any one of Claims 1-3.

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