JP2006149144A - Micro motors, sliding contact therefor, manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sliding contact for a micro motor, being environment-friendly, of which wear resistance of a commutator and brush is improved than before, for better connection to a copper wire. <P>SOLUTION: The sliding contact comprises a brush 16 comprising a coating layer 32 for a first brush of the metal of either nickel base or cobalt base which is formed on a first conductive substrate 31, and a coating layer 33 for a second brush of palladium base metal which is formed on the coating layer 32 for the first brush. It also comprises a coating layer 22 for a first commutator of the metal of either nickel base or cobalt base on a second conductive substrate 21, a coating layer 23 for a second commutator of the metal of silver base formed on the coating layer 22 for the first commutator, a stripe-like metal layer 25 of silver base of the coating layer 23 for the second commutator that is formed in the region contacting the brush 16, and a tin base metal layer 24 of the coating layer 23 for the second commutator formed in the region to which copper material is connected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a micromotor, a sliding contact for a micromotor, and a manufacturing method thereof, and more specifically, a sliding contact for a micromotor composed of a commutator and a brush, a manufacturing method thereof, and a micro having the sliding contact. Regarding motors.

  Micromotors are widely used in many applications such as acoustics, home appliances, and automobiles. The life of a micromotor is mainly determined by the durability of a commutator and a brush that are members for energizing a motor coil.

  These materials require materials with excellent wear resistance, arc resistance, electrical connectivity, electrical conductivity, and mechanical strength, and are generally copper (Cu) alloys coated with silver (Ag) alloys. Strips (hereinafter referred to as Ag alloy-coated Cu alloy strips) are used. This Ag alloy-coated Cu alloy strip is a high-performance conductor that combines the wear resistance, arc resistance, and high electrical connection properties of silver alloys with the strength and high conductivity properties of copper alloys. is there.

  In addition to the above-described characteristics, the commutator material further requires connectivity with the motor coil copper wire and solder jointability with the disk varistor. In addition, the end of the Ag alloy-coated Cu alloy strip has a structure in which tin lead (SnPb) solder plating for connection to the copper wire of the motor coil is applied. SnPb solder plating is performed by hot dipping or electroplating.

  The substrate used for the commutator material has a plate thickness of 0.1 mm to 0.3 mm, and is made of copper tin (CuSn), copper nickel (CuNi), or pure copper. As the silver alloy for covering the film, silver cadmium (AgCd), silver magnesium (AgMg), silver copper (AgCu), and silver nickel (AgNi) are used. The inlay material which coat | covered only the contact part with a brush for the coating which consists of silver alloys is common, and the thickness is 20-100 micrometers.

  On the other hand, since the brush material requires stable contact pressure, wear resistance and low contact resistance, a copper alloy having a spring thickness of about 0.03 mm to 0.1 mm is used for the base material. Further, a silver palladium (AgPd) alloy having a thickness of 5 μm to 20 μm is applied to the contact portion with the commutator.

  Note that the brush material and the commutator material are manufactured by combining a copper alloy base material with a silver alloy tape by a clad method such as hot pressing, cold pressing, or seam welding.

  Patent Document 1 and Patent Document 2 below describe forming a three-layered film on the surface of a copper alloy substrate constituting a commutator or a brush. The first layer of the three-layer structure is made of chromium (Cr), nickel (Ni), nickel alloy, or rhenium (Re) having a thickness of 0.2 μm to 10 μm, and the second layer is It is composed of any one of rhodium (Rh), platinum (Pt), palladium and ruthenium (Ru) having a thickness of 0.1 μm to 10 μm, and the third layer is gold (Au) having a thickness of 0.1 μm to 10 μm, It is composed of either silver or gold-silver alloy.

JP 58-218782 A JP 58-218783 A

  Conventional commutators and brushes formed by forming a silver alloy coating on the surface of the copper alloy material as described above have the following problems.

  First, since silver alloy has a high coverage, the cost is high, and when cadmium is contained, there is a risk of polluting the environment. Furthermore, if the silver alloy tape is manufactured by the clad method, the manufacturing cost is increased.

  In addition, the cladding method is a method including a step of repeating annealing and rolling. Since a deformed layer is formed on the surface of the silver alloy, the silver alloy tape of the alloy material formed by this method has an arc resistance. Inferior, since the commutator and the brush are worn faster, the life of the motor is shortened, and on the surface, alloy components other than silver are densified, resulting in inferior corrosion resistance.

  Further, when SnPb solder plating is performed on a silver alloy material, not only the lead time is increased, but also the environment is contaminated because lead (Pb) is contained in the solder plating. When SnPb solder plating is applied by the hot dipping method, there is a large variation in the connection strength between the motor coil and the copper wire due to large variations in plating thickness and a lot of powder falling off during pressing for shaping. .

  In the commutator material and the brush material formed by the clad method, the copper alloy base material is exposed as it is in the portions other than the silver alloy coating portion and the solder plating portion, so that the copper alloy base material having poor corrosion resistance is oxidized or the like. As a result, the discoloration occurs, and when the discoloration progresses, the contact between the commutator and the brush is contaminated due to the creep phenomenon of the corrosion product, resulting in a contact failure.

  On the other hand, since the soldering with the disk varistor is applied to the copper alloy surface which is the back side of the silver alloy surface formed by the clad method, the connection strength varies.

  In order to solve these problems, the development of new silver alloy compositions and the use of gold or gold alloys on the silver alloy coating for coating have been carried out, but only some of the problems have been solved. Overall improvement was desired.

  Further, as described in Patent Document 1 and Patent Document 2, when the above-described three-layer structure is applied to the surface of the commutator or the brush and the conventional material is used on the other side, the processing deformation peculiar to the above-described clad material The life of the motor is not improved sufficiently due to the influence of the layer and corrosion resistance. In addition, when the materials described in these documents are combined and applied to a micromotor, the surfaces of the commutator and the brush are made of soft gold, silver, gold-silver alloy. Adhesive wear occurs, resulting in inferior motor life compared to conventional combinations of clad materials.

  Further, the portion of the motor coil that connects the copper wire and the commutator is not described in Patent Document 1 and Patent Document 2 described above, and the conventional molten solder plating is applied. The problem is not solved.

  An object of the present invention is to provide a micromotor, a sliding contact for a micromotor, and a method for manufacturing the same, which are environmentally friendly, can improve the wear resistance of a commutator and a brush, and can be well connected to a copper wire. Is to provide.

  A sliding contact for a micromotor according to a first aspect of the present invention for solving the above-described problem is a first conductive base and a nickel-based or cobalt-based formed on the first conductive base. A brush having a first brush coating layer made of any one of the metals, and a second brush coating layer made of a palladium-based metal formed on the first brush coating layer; Two conductive bases, a first commutator coating layer made of nickel or cobalt metal on the second conductive base, and the first commutator coating layer. A second commutator coating layer made of a silver-based metal formed on the second commutator; a striped silver-based metal layer formed in a region in contact with the brush in the second commutator coating layer; 2 of the commutator coating layer 2 formed in the region to which the copper wire is connected. And a commutator having a system metal layer.

  In the sliding contact for a micromotor according to the second aspect of the present invention, a metal layer made of either gold-based or palladium-based metal is formed on the striped silver-based metal layer of the commutator. It is characterized by being.

The sliding contact for a micromotor according to a third aspect of the present invention is characterized in that the tin-based metal layer of the commutator is subjected to a reflow process and has a smooth surface.
In the sliding contact for a micromotor according to the fourth aspect of the present invention, a striped palladium-based metal layer is formed on a region of the second brush coating layer in contact with the commutator. It is characterized by that.

  A micromotor according to a fifth aspect of the present invention has the sliding contact for a micromotor according to any one of the first to fourth aspects of the present invention.

  According to a sixth aspect of the present invention, there is provided a method for manufacturing a sliding contact for a micromotor, wherein a first covering layer made of either nickel-based or cobalt-based metal on a first conductive substrate constituting a brush. A second coating layer made of a palladium-based metal that covers the first coating layer, and a striped palladium-based metal layer that covers a commutator contact region on the second coating layer A step of forming at least the second coating layer on the lower side, and forming at least one of the second coating layer serving as the uppermost layer and the striped palladium-based metal layer by plating. It is characterized by.

  According to a seventh aspect of the present invention, there is provided a method for manufacturing a sliding contact for a micromotor, wherein a first coating made of a nickel-based or cobalt-based metal on a second conductive substrate constituting a commutator. A step of forming a layer, a step of forming a second coating layer made of a silver-based metal on the first coating layer, and a striped silver-based material in a contact region with a brush in the second coating layer A step of forming a metal layer, and a step of forming a tin-based metal layer on a region of the second coating layer to which a copper wire is connected, at least the striped silver-based metal layer and the tin-based layer The metal layer is formed by plating.

  The method for manufacturing a sliding contact for a micromotor according to an eighth aspect of the present invention is characterized in that either a gold-based or palladium-based metal layer is formed by plating on the striped silver-based metal layer. And

  A manufacturing method of a sliding contact for a micromotor according to a ninth aspect of the present invention includes a step of reflowing the tin-based metal layer after forming the tin-based metal layer.

  The nickel-based metal is nickel or a nickel alloy, the cobalt-based metal is cobalt or a cobalt alloy, the silver-based metal is silver or a silver alloy, the palladium-based metal is palladium or a palladium alloy, and the tin-based metal is It is tin or a tin alloy, and the gold-based metal is gold or a gold alloy.

  According to the present invention, a brush is formed from a layer structure in which a nickel-based metal layer or a cobalt-based metal layer is formed on a conductive substrate, and a palladium-based metal layer is formed thereon, while the conductive substrate is formed. A commutator is formed from a layer structure in which a nickel-based metal layer or a cobalt-based metal layer is formed thereon, and a silver-based metal layer is formed thereon, and the brush contacts the silver-based metal layer of the commutator. A striped silver-based metal layer is formed in a region to be processed, and a tin-based metal layer is formed in a region to which a copper material is connected.

  The nickel-based metal layer or the cobalt-based metal layer prevents the diffusion of the components of the conductive substrate constituting the brush and the commutator. In addition, the silver-based metal layer formed on the nickel-based metal layer or the cobalt-based metal layer in the commutator prevents corrosion of the conductive base material and also has solderability with a disk varistor connected to the commutator. To improve. Further, the tin-based metal layer formed on the silver-based metal layer is formed in a region connected to the copper wire, but by melting with the silver-based metal by reflow or the like, the melting point is lowered and the copper wire and The reliability of the connection is improved and the adhesion is improved, so that powder falling during pressing is suppressed. In addition, since the striped silver metal layer protrudes from the commutator in the contact area with the brush, the silver metal layer can be made thin in areas other than the contact area with the brush. The amount can be reduced and the economy can be improved. In addition, since the deformed layer is not formed because the clad structure is not formed, it is difficult to generate an arc, and the wear rate can be reduced.

  In a brush, a nickel-based metal layer covering a conductive substrate or a palladium-based metal layer formed on the surface of a cobalt-based metal has excellent wear resistance and corrosion resistance, and has low contact resistance, so it is pressed against the brush commutator. The pressure can be lowered and the life of the sliding contact can be extended.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a cross-sectional view of an essential part showing an example of a micromotor according to the present invention.

  In FIG. 1, a micromotor 1 has a hollow cylindrical metal case 2 having a closed portion 2a at one end, and a permanent magnet 3 is fixed in an arc segment shape on the inner peripheral surface thereof. A bearing 4 is attached to the center of the closed portion 2a. A rotor 5 is attached inside the metal case 2.

  The rotor 5 includes a rotating shaft 6 having one end passing through the bearing 4 of the closing portion 2a of the metal case 2, a motor coil 7 attached to the rotating shaft 6 and accommodated in the metal case 2, and a rotating shaft. 6 and a commutator 8 attached in the vicinity of the other end. The motor coil 7 is configured by winding a copper wire 7a around an iron core 9 through which a rotating shaft 6 passes.

  As shown in FIG. 2, the commutator 8 is attached to the outer periphery of an insulating commutator core 10 fixed on the rotating shaft 6, and a convex portion 8 a is formed at an end portion close to the motor coil 7. Yes. A disc varistor 11 attached to the outer periphery of the commutator 8 is connected to the convex portion 8a by SnPb solder 12, and a copper wire 7a of the motor coil 7 is connected by solder.

  An insulating case cap 13 is attached to the open end of the motor case 2, and a bearing 14 that supports the other end of the rotating shaft 6 is fitted in the center thereof. Further, a conductive terminal 15 is attached to the outer periphery of the case cap 13 so as to protrude outward from the inside of the metal case 2. Further, a brush 16 connected to the conductive terminal 15 is fixed to a portion of the case cap 13 facing the commutator 8, and the brush 16 is spring-like so as to be in sliding contact with the outer peripheral surface of the commutator 8. have.

  The commutator 8 and the brush 16 are sliding contacts for supplying electric power to the rotating motor coil 7, and the commutator 8 is formed of, for example, a commutator material shown in FIG. It is formed from the brush material as shown in FIG.

  As the conductive bases 21 and 31 constituting the commutator 8 and the brush 16, for example, copper, nickel (Ni), iron (Fe), or an alloy thereof, or copper or a copper alloy is used for a steel material, an aluminum material, or the like. A coated composite material or the like is applied. The thickness of the conductive substrate 21 for the commutator is 0.15 to 0.3 mm, for example, 0.3 mm. Moreover, the thickness of the conductive base 31 for brushes is 0.03-1.0 mm, for example, 0.05-0.07. A coating layer suitable for each of the commutator 8 and the brush 16 is formed on the surfaces of the conductive substrates 21 and 31.

  As illustrated in FIG. 3, the commutator material is composed of the first covering layer 22 mainly composed of nickel, cobalt (Co), or an alloy thereof, and silver or a silver alloy on the conductive base 21. The 2nd coating layer 23 which becomes is formed in order. Nickel alloys include NiCo, NiZn, NiSn, NiFe, NiP, and NiB. Cobalt alloys include CoNi, CoZn, CoSn, CoFe, CoP, and CoB.

  The first covering layer 22 of the commutator material functions as a diffusion barrier that prevents the diffusion of the components of the conductive substrate 21, and the thickness thereof is not particularly limited, and is, for example, in the range of 0.1 to 10 μm. Although it is formed, the thickness is preferably 0.5 to 2.0 μm in consideration of improvement of diffusion barrier performance and economy.

  Further, the second coating layer 23 of the commutator material has a function of preventing the corrosion of copper constituting the conductive base 21 and improving the solder jointability with the disk varistor 11. Although the thickness of the 2nd coating layer 23 is not specifically limited, For example, it is given in the range of 0.005-2.0 micrometers, and when the improvement of solderability and economical efficiency are considered, it is 0.05-0. A range of 5 μm is preferable.

  In the commutator 8, in a region to be the convex portion 8 a to which the copper wire 7 a of the motor coil 7 is connected, a connection layer 24 made of a tin (Sn) layer or a tin alloy layer is formed on the second coating layer 23. ing. Examples of tin alloys include SnZn, SnCu, SnBi, SnAg, and SnNi.

  The connection layer 24 made of a tin layer or a tin alloy layer is preferably formed by an electroplating method in order to make the distribution of the plating coating film thickness uniform, and the adhesion is improved by reflowing after the formation. The powder fall off during press working is greatly reduced and the surface becomes smooth. Further, the tin layer or the tin alloy layer is alloyed with silver or a silver alloy constituting the second coating layer 23 which is the underlayer by reflow treatment to form a tin-silver alloy, whereby the melting point is lowered and the copper wire is formed. The reliability of connection with 7a is improved. In this case, the crystal grain size of tin becomes large, the diffusion reaction rate with the base is slow, and the tin layer is hardly deteriorated. The thickness of the tin layer or the tin alloy layer is not particularly limited, but is applied in the range of 0.5 to 10 μm, for example, in consideration of improved connection reliability, prevention of powder falling off during pressing, and economic efficiency. It is preferable to form in the range of 0-6.0 micrometers.

  In the region of the commutator 8 in contact with the brush 16, a contact layer 25 made of a striped silver layer or silver alloy layer is formed on the second coating layer 23 by electroplating. Since the deformation layer is not formed on the silver layer or the silver alloy layer, an arc is hardly generated when the commutator 8 is rotated, and the wear rate is reduced. In addition, by forming the silver layer or the silver alloy layer in a stripe shape, the amount of noble metal used is reduced and the economic efficiency is enhanced. The thickness of such contact layer 25 is determined from the required life of the motor and is coated in the range of, for example, about 1.0 μm for low life motors and for example in the range of 5.0-20 μm for long life motors.

  Further, if a protective layer 26 made of a gold (Au) layer or a gold alloy layer, or a palladium (Pd) layer or a palladium alloy layer is formed on the stripe-shaped contact layer 25, the contact layer 25 is further brought into contact with the brush 16. The wear rate can be reduced. The thickness of the protective layer 26 is not particularly limited. For example, the protective layer 26 is applied in the range of 0.001 to 1.0 μm, and 0.01 to 0.5 μm in consideration of corrosion resistance, wear resistance, and economy. It is preferable to set it as the range.

  The brush 16 used in combination with the commutator 8 having such a structure has a first coating layer 32 mainly composed of nickel, cobalt, or an alloy thereof, palladium on the entire surface of the conductive base 31. It has a structure in which a second coating layer 33 made of (Pd) or a palladium alloy is formed in order.

  The first coating layer 32 functions as a diffusion barrier that prevents the diffusion of the components of the conductive substrate 31, and the second coating layer 33 is excellent in wear resistance and corrosion resistance and has low contact resistance. In order to be excellent in durability, it is formed in order to prevent deterioration of corrosion resistance of copper constituting the conductive substrate 31.

  Since the second coating layer 33 is formed by electroplating, it is difficult for deformation to occur, and since an arc is not easily generated when sliding with the commutator 8, the wear rate is slow, and further, electrical connectivity and heat resistance are reduced. Excellent in oxidation resistance and corrosion resistance. Therefore, when the brush 16 and the commutator 8 having the above structure are used in combination, the pressing pressure of the brush 16 against the commutator 8 can be reduced as compared with the structure using the conventional clad material.

  Thereby, the thickness of the palladium layer and the palladium alloy layer constituting the second coating layer 33 can be significantly reduced, and the formation time can be shortened and the economy can be improved. Although the thickness is not specifically limited, For example, it forms in the range of 0.1-5.0 micrometers. In this case, if the thickness is less than 0.1 μm, the plating thickness is too thin and the contact resistance increases, and if it is 5.0 μm or more, there is no problem in use, but it is not preferable from the viewpoint of economy. The range is 0 μm.

A stripe layer 34 made of a palladium layer or a palladium alloy layer is formed in a region in contact with the commutator 8 in the second covering layer 33. Thereby, the usage-amount of palladium decreases and it is economical. The stripe layer 34 may be omitted.
The silver alloy layer formed on the conductive substrates 21 and 31 is not particularly limited, and examples thereof include layers such as AgSb alloy, AgSe alloy, AgPd alloy, AgAu alloy, and AgMg alloy. The palladium alloy layer formed on the conductive substrates 21 and 31 is not particularly limited, but there are layers such as a PdNi alloy, a PdAg alloy, a PdCo alloy, and a PdAu alloy.

Next, the commutator 8 and the brush 16 described above will be described in more detail.
As the conductive substrate 21 used for the commutator material of the commutator 8, an alloy strip of the copper alloy standard C14410 of the US Copper Development Association (CDA) having a thickness of 0.3 mm and a width of 20 mm is used. After passing through a line for plating the material, and performing electrolytic degreasing and pickling treatment on the surface, electroplating is performed as shown in Table 1. C14410 has a tin content of 0.1 to 0.2 wt. % And the balance is copper.

  In Table 1, this invention material No. which shows the metal material for commutators is shown. 1 to 5 are materials and thicknesses of the first coating layer 22, the second coating layer 23, the contact layer 25, and the connection layer 24 that are sequentially formed on the conductive substrate 21 as shown in FIG. Is shown. Further, the connection layer 24 made of tin or tin alloy is reflowed after the formation. The reflow treatment was performed for 5 seconds in a reflow furnace set at a furnace temperature of 500 ° C. Further, the conventional material 1 of the commutator plating material shown in Table 1 shows a conventional structure formed by a clad method, and the solder layer is formed by tin-plated solder by hot dipping. In addition, the electroconductive base material of this invention materials 1-5 and the conventional material 1 is the same Cu alloy strip, is CAD specification C14410, and uses the brand name FFTEC-3 of Furukawa Electric Co., Ltd.

  On the other hand, as the conductive base 31 used for the brush material of the brush 16, an alloy strip of US CDA copper alloy standard C77000 having a thickness of 0.07 mm and a width of 20 mm is used, and this strip is continuously plated. After passing through the line and subjecting the surface to electrolytic degreasing and pickling, the plating shown in Table 1 is performed by electroplating.

  In Table 1, this invention material No. which shows the metal material for brushes. 6 and 7 show the materials and thicknesses of the first covering layer 32, the second covering layer 33, and the stripe layer 34, which are sequentially formed on the conductive substrate 31, as shown in FIG. Yes. Further, the conventional material 2 of the brush plating material shown in Table 1 shows a conventional structure formed by the clad method. The conductive substrates of the present invention materials 6 and 7 and the conventional material 2 are the same copper alloy strips, and use product number C7701R of Mitsubishi Electric Metex Co., Ltd., which is a white strip for springs of CAD standard C77000. C7701R contains 50 to 70 wt. %, Zinc 15-35 wt. %, Nickel 5 to 35 wt. % Content.

Such electroplating is performed with a liquid, temperature, and current under the following conditions.
The plating solution used for nickel plating contains NiSO ₄ , NiCl ₂ , and H ₃ BO ₃ at concentrations of 240 g / l, 45 g / l, and 30 g / l, respectively, and heats them to a temperature of 50 ° C. for plating. The current flowing through the electrode is 5 A / dm ² .

The plating solution used for cobalt plating contains CoSO ₄ , NaCl, and H ₃ BO ₃ at concentrations of 400 g / l, 20 g / l, and 40 g / l, respectively, and sets the temperature to 30 ° C. and plating. The current flowing through the working electrode is 5 A / dm ² .

The plating solution used for NiPd plating containing 80 wt.% Palladium and 20 wt.% Nickel is Pd (NH ₃ ) ₂ Cl ₂ , NiSO ₄ , NH ₄ OH and (NH ₄ ) ₂ SO ₄ . These are contained at concentrations of 40 g / l, 45 g / l, 90 g / l and 50 g / l, respectively, and this is set at a temperature of 30 ° C. and the current passed through the plating electrode is 1 A / dm ² .

The plating solution used for silver plating to form a stripe-shaped silver layer contains AgCN, KCN, and K ₂ CO ₃ at concentrations of 50 g / l, 100 g / l, and 30 g / l, respectively. The temperature is set to 0 ° C. and the current passed through the plating electrode is 2 A / dm ² .
Moreover, the liquid used for plating for forming the tin layer is an organic acid-based plating solution to which a smoothing agent is added. This is set at a temperature of 20 ° C. and a current flowing through the plating electrode is 10 A / dm ² . A tin plating solution containing 400 g / l of tin alkanol sulfonate, 100 g / l of alkanol sulfonic acid and 20 cc / l of an additive (product number: 513Y) manufactured by Ishihara Yakuhin is used.

The plating solution used for silver plating contains AgCN, KCN, and K ₂ CO ₃ at concentrations of 50 g / l, 50 g / l, and 30 g / l, respectively, and is set at a temperature of 30 ° C. The current flowing through the plating electrode is 1 A / dm ² .
Furthermore, the plating solution used for palladium plating contains Pd (NH ₃ ) ₂ Cl ₂ , NH ₄ OH and (NH ₄ ) ₂ SO ₄ in concentrations of 45 g / l, 90 g / l and 50 g / l, respectively. Is set to a temperature of 30 ° C. and the current passed through the plating electrode is set to 1 A / dm ² .

About the commutator material formed by the above method and the conventional method, the soldering performance in the region where the contact layer 25 made of striped silver or silver alloy and the connection layer 24 made of tin or tin alloy are not formed As a result of the evaluation, the results shown in Table 2 were obtained. In the evaluation, SnPb eutectic solder was used as the solder, and rosin dissolved in IPA (isopropyl alcohol) at 25 wt.% Was used as the flux.

  According to Table 2, as the commutator material, the present invention material No. It can be seen that 1 to 5 have a shorter solder wetting time and better adhesion than Conventional Example 1.

  Next, the present invention material No. The commutator materials 1 to 5 and the conventional example 1 were shaped by a press and examined for the generation of tin powder. It became clear that the amount of powder falling from 1 to 5 was less than the amount of powder falling from Conventional Example 1.

Further, in the combinations shown in Table 1, the present invention material No. 1 to 5 commutator material and the present invention material No. A micromotor according to Examples 1 to 6 of the present invention incorporating a commutator 8 and a brush 16 obtained by pressing each of the brush materials 6 and 7, a commutator using the conventional material 1, and the conventional material 2. When the motor life test was performed on each of the micromotors incorporating the brushes used, the results shown in Table 3 were obtained. Further, in Table 3, Comparative Example 1 and 2 show experimental results when using a conventional clad material for one of the commutator and the brush. In Table 3, the materials of the commutator and the brush are shown based on the display in Table 1.

  Table 3 shows that the power is continuously supplied to the micromotor, the stop time until the rotation of the armature 5 stops naturally, and the silver layer or the silver alloy coating of the commutator 8 based on the stop time. The lifetime per 1 μm thickness is shown. These micromotors were driven under the conditions of a driving voltage of 2.5, a driving current of 0.2 A, and a rotation speed of 2000 rpm.

  As is clear from Table 3, according to the sliding contact constituted by the combination of the commutator 8 and the brush 16 according to the first to sixth embodiments of the present invention, the thickness of the silver layer or the silver alloy layer of the commutator 8. It can be seen that the life of the hit motor is more than four times that of the conventional examples 1 and 2, and the life is greatly extended.

  In addition, when a clad material is used for one contact of the commutator 8 and the brush 16, the effect of extending the life cannot be obtained, and the combination of the commutator and the brush having the structure of the present invention extends the motor life. I understand.

FIG. 1 is a side view showing a micromotor according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a commutator constituting a sliding contact of the micromotor according to the embodiment of the present invention. FIG. 3 is a cross-sectional view showing a commutator material used for a commutator constituting a sliding contact of a micromotor according to an embodiment of the present invention. FIG. 4 is a cross-sectional view showing a brush material used for a brush constituting a sliding contact of a micromotor according to an embodiment of the present invention.

Explanation of symbols

1: Micromotor 8: Commutator 21: Conductive substrate 22: First coating layer 23: Second coating layer 24: Connection layer 25: Contact layer 16: Brush 31: Conductive substrate 32: First coating layer 33: Second coating layer 34: Stripe layer

Claims (9)

A first conductive substrate, a first brush coating layer formed on the first conductive substrate and made of either nickel-based or cobalt-based metal, and the first brush coating layer A brush having a second brush coating layer made of a palladium-based metal formed thereon;
A second conductive substrate, a first commutator coating layer made of nickel or cobalt metal on the second conductive substrate, and a first commutator coating layer. A second commutator covering layer made of silver-based metal formed on the top, a striped silver-based metal layer formed in a region in contact with the brush in the second commutator covering layer, and A sliding contact for a micromotor, comprising: a commutator having a tin-based metal layer formed in a region to which a copper material is connected in the second commutator coating layer. 2. The micromotor according to claim 1, wherein a metal layer made of either a gold-based metal or a palladium-based metal is formed on the striped silver-based metal layer of the commutator. Sliding contact. The sliding contact for a micromotor according to claim 1 or 2, wherein the tin-based metal layer of the commutator is subjected to a reflow process and has a smooth surface. 4. The striped palladium-based metal layer is formed on a region of the second brush coating layer that contacts the commutator. 5. The sliding contact for micro motors described in 1. A micromotor comprising the sliding contact for a micromotor according to claim 1. Forming a first coating layer made of one of nickel-based and cobalt-based metals on the first conductive substrate constituting the brush;
At least the lower side of the second coating layer made of palladium-based metal covering the first coating layer and the stripe-shaped palladium-based metal layer covering the commutator contact region on the second coating layer Forming a second coating layer,
At least one of the second coating layer and the striped palladium-based metal layer, which is the uppermost layer, is formed by plating. Forming a first coating layer made of one of a nickel-based metal and a cobalt-based metal on a second conductive substrate constituting the commutator;
Forming a second coating layer made of a silver-based metal on the first coating layer;
Forming a stripe-shaped silver-based metal layer in a contact region with the brush in the second coating layer;
Forming a tin-based metal layer on a region to which a copper wire is connected in the second coating layer,
A manufacturing method of a sliding contact for a micromotor, wherein at least the striped silver metal layer and the tin metal layer are formed by plating. 8. The method of manufacturing a sliding contact for a micromotor according to claim 7, wherein either a gold-based or palladium-based metal layer is formed on the striped silver-based metal layer by plating. The method for manufacturing a sliding contact for a micromotor according to claim 7, further comprising a step of reflowing the tin-based metal layer after forming the tin-based metal layer.

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