JP2002126642A - Magnetic kinetic mass part for mobile telecommunication equipment and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a magnetic kinetic mass part for a mobile telecommunication equipment which improves the adhesiveness between a holder of a zinc die casting and rare earth magnets, also improves moisture resistance, suppresses the deterioration of the adhesiveness particularly after storage at low temperatures and is excellent in reliability. SOLUTION: The magnetic kinetic mass part has rare earth magnets 10A, 10B bonded to a holder 1 obtained by successively forming a Cu plating layer as an underlayer and a plating layer of one or more selected from Ni and Ni-P, Ni-B and Ni-Sn alloys on a zinc die casting. The rare earth magnets 10A, 10B are Nd-Fe-B magnets each with a plating layer of Ni or an Ni-P, Ni-B or Ni-Sn alloy formed on the top.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic motion mass unit for a mobile communication device suitable for use in a vibration driving device for detecting an incoming call used in a cellular phone or the like, and a method of manufacturing the same.
In particular, the present invention relates to a surface treatment of a holder (zinc die-cast part) and a rare earth magnet which are constituent members of a magnetic kinetic mass part.

[0002]

2. Description of the Related Art In recent years, with the miniaturization and high performance of portable telephones, there has been a further demand for further miniaturization of the magnetic motion mass used in the vibration drive device for incoming call detection. In order to simultaneously satisfy the requirements for miniaturization and high output of the magnetic kinematic mass, the magnetic properties of the magnetic kinematic mass must be high,
High specific gravity.

At present, the Nd-Fe-B magnet is the magnet having the most excellent magnetic properties, and is suitable for use in a vibration driving device for incoming call detection. However, it has a disadvantage that it is very susceptible to corrosion, so that various surface treatments have been applied. Particularly in the case of small articles, nickel (Ni) plating, which is excellent in balance between quality and cost, is most often applied.

On the other hand, zinc die casting has been selected as a component material of the magnetic kinematic mass part because it has a high specific gravity and is inexpensive as a member constituting the magnetic kinematic mass part. Usually, zinc (Zn) is very easily rusted, and therefore some treatment is performed. Above all, chromate treatment, C
Until now, u + Sn plating has been widely adopted for those using zinc as a raw material.

However, since the use of the chromate treatment is being restricted due to recent environmental problems, Cu + Sn
Plating has been applied to ensure corrosion resistance.

The magnetic kinetic mass of the present invention has a structure in which zinc die casting and a rare earth magnet are fixed with an adhesive as described in Japanese Patent No. 2987936. However, when an Sn layer is formed on the surface of the adherend, Sn undergoes a phase change in a low-temperature region (change from β phase to α phase Sn), expands in volume, and peels off the adhesive interface (tin pest is generated). ) There was a problem. Further, chemicals and techniques as alternatives to the conventional chromate treatment have been intensively studied by each manufacturer, but sufficient performance has not yet been obtained.

[0007]

SUMMARY OF THE INVENTION In view of the above, the present invention improves the adhesion and moisture resistance between a zinc die casting holder and a rare earth magnet, and particularly suppresses the deterioration of adhesion after storage at low temperatures. It is an object of the present invention to provide a magnetic motion mass part for a mobile communication device capable of realizing excellent reliability and a method of manufacturing the same.

[0008] Other objects and novel features of the present invention will be clarified in embodiments described later.

[0009]

In order to achieve the above object, a magnetic kinetic mass for a mobile communication device according to the present invention comprises:
In the configuration in which the rare earth magnet is bonded to the holder, the holder is a zinc die-cast, a Cu plating layer as a base, and further, at least one of Ni, a Ni-P alloy, a Ni-B alloy, and a Ni-Sn alloy. It is characterized in that the plating layers are sequentially laminated.

In the magnetic mass unit for mobile communication equipment, the rare earth magnet is an Nd—Fe—B magnet.
Ni, Ni-P alloy, Ni-B alloy, Ni-S on the outermost surface
It is preferable that one of the plating layers of the n alloy is formed.

Further, the Nd-Fe-B-based magnet may have a Cu plating layer as a base of the plating layer on the outermost surface.

According to the method of manufacturing a magnetic motion mass part for mobile communication equipment according to the present invention, a method of manufacturing
After forming the plating layer, a holding member preparing step of forming a holding member by laminating any one or more plating layers of Ni, Ni-P alloy, Ni-B alloy, and Ni-Sn alloy to form a holding member; Ni, Ni-P alloy, Ni-B alloy,
A surface treatment step of a rare earth magnet for forming any plating layer of a Ni-Sn alloy; and a fixing step of fixing the rare earth magnet after the surface treatment step to the holder with an adhesive. I have.

[0013] In the method of manufacturing a magnetic kinetic mass for a mobile communication device, the Cu plating layer as the base may be treated at least initially using an alkali chelating bath having a pH of 7 to 10.

[0014]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a magnetic mass unit for a mobile communication device according to an embodiment of the present invention;

FIG. 1 is an embodiment of the present invention, and is an exploded view before a rare earth magnet is bonded to a holder, FIG. 2 is a front view after the bonding, and FIG. 3 is a plan view of the same.

As shown in these figures, the magnetic kinematic mass for mobile communication equipment comprises a holder 1 and square plate-shaped rare earth magnets 10A and 10B bonded to the front and back sides thereof with the same polarity. .

The holder 1 is a rectangular plate-shaped rare earth magnet 10A,
10B has upper and lower flat main surfaces 2A and 2B bonded to each other with a wide surface, and rare earth magnets 10A and 10B.
B and end side walls 3A and 3B surrounding the end of B and rare earth magnet 1
Intermediate side wall 4 for holding the intermediate part of 0A and 10B
A, 4B.

The holder 1 is obtained by subjecting a zinc die-cast having the above-mentioned shape to a surface treatment for rust prevention, that is, a plating treatment, and the steps will be described below.

First, zinc die casting is immersed in a cleaning solution containing sodium carbonate as a main component at 70 ° C. for 30 seconds, and then washed with pure water.

After washing, strike plating is performed in a copper chelate bath, which is an alkaline chelate bath having a pH of 7 to 10, to form a thin 3 to 7 μm Cu plating layer on the surface of the zinc die-cast, followed by plating in a copper pyrophosphate bath. 6-1 finally
A Cu plating layer of 2 μm is formed. In addition, you may form a 6-12 micrometers Cu plating layer only with a copper alkali chelate bath.

After the copper plating, a Ni plating layer is formed in a Watts bath in a thickness of 5 to 10 μm, and the surface treatment of the zinc die casting is completed.

Here, the reason why the Cu plating process is performed on the zinc die casting will be described. Since zinc is an amphoteric metal and has the property of dissolving in both acids and alkalis, a substitution reaction occurs immediately when Ni plating or the like is performed directly, and a metal layer is deposited on the surface. However, since the degree of adhesion is inferior and swelling occurs, weakly alkaline Cu plating is performed as the base plating.

The strike plating in the copper plating step is described in JIS H 0404-308 as "strike is to perform short-time plating using special working conditions or bath composition". Substantially, the purpose is to improve the adhesion and covering power of the plating and to prevent the substitution action, and the plating is performed in a short time using a plating solution having a lower metal ion concentration than a normal plating solution. In the process, it serves as a bridge between pretreatment (cleaning and the like) and plating, and should be referred to as preplating.

As for a copper plating bath for forming a Cu layer, generally, copper has a low ionization tendency and it is difficult to perform plating with good adhesion to steel or the like. Apply a thin plating layer with good adhesion from the bath (chelate bath). This operation is called strike.

Copper plating baths are broadly classified into copper sulfate baths, copper cyanide baths, and copper pyrophosphate baths. For zinc, a copper cyanide bath which is a chelating bath is often used. However, cyan has been shunned in recent years due to environmental problems, and those using organic chelating agents such as EDTA (ethylenediaminetetraacetic acid), amines such as methylamine, and organic phosphonic acids such as triethyl phosphite have been developed. In the present embodiment, in the strike plating process, a cyan substitution copper plating bath (pH 7 to 10 alkaline chelating bath using an organic chelating agent) is used. However, even if a copper cyanide bath is used as before, there is no problem in function.

Further, strike plating is performed and 3 to 7 μm
After forming a Cu plating layer of m and plating in a copper pyrophosphate bath to finally form a Cu plating layer of 6 to 12 μm, a weak alkali chelating bath of PH7 to 10 using the organic chelating agent is expensive. This is because it is preferable in terms of cost to use inexpensive copper pyrophosphate if it can trigger the formation of the Cu plating layer. Further, the final formation of the Cu plating layer of 6 to 12 μm in the copper pyrophosphate bath is required to reduce the adhesion at the time of the next plating unless the final underlayer Cu layer is made to be about 6 to 12 μm. It is because it causes.

The reason why Ni plating is formed after copper plating is that Sn plating is usually performed on the Cu layer, but the low temperature storage after bonding and the phase change of Sn occur in a thermal shock test, and the bonded portion is peeled off. For. Ni is selected as plating which is inexpensive and has excellent corrosion resistance.

The Watts bath used in the Ni plating step is a plating bath containing nickel sulfate, nickel chloride and boric acid as main components. Invented by Watts in 1916, plating can be performed quickly at high temperatures and large current densities.
Since the bath is also inexpensive, it is Ni plating that is frequently used unless otherwise specified for dimensional accuracy, film hardness, and the like. In addition, even if Ni plating is performed in another plating bath, there is no problem in function.

Next, after Nd-Fe-B-based sintered magnets (elements of rare-earth magnets before surface treatment) are barrel-polished, they are etched in a nitric acid solution, subjected to ultrasonic cleaning, and further to pure water cleaning. . The washed magnet is subjected to strike plating in a copper chelate bath (similar to that used for zinc die-casting), which is a weak alkali chelate bath of pH 7 to 10, and 3 to 7 μm
After forming the Cu plating layer, plating is performed in a copper pyrophosphate bath to finally form a Cu plating layer having a thickness of 6 to 12 μm.
After Cu plating, the Ni plating layer is placed in a Watts bath for 5 to 10 minutes.
μm is formed.

The phosphate treatment applied to the steel material may be performed on Ni plating to improve the bonding strength.

Further, after the element body of the rare earth magnet before the surface treatment is subjected to barrel polishing and ultrasonic cleaning, Cu plating is omitted and Ni plating treatment is performed to reduce the Ni plating layer to 5 to 10 μm.
m may be formed.

The rare earth magnets 10A, 10B obtained by magnetizing the plated magnet as described above are applied to the upper and lower main surfaces 2A, 2B of the holder 1 made of plated zinc die cast. And fix them using an epoxy adhesive so that magnetic poles of the same polarity face each other. At this time, not only the main surfaces 2A and 2B of the holder 1 but also the end side walls 3A and 3B.
An adhesive is also applied to the inner wall surfaces of the intermediate side walls 4A and 4B, and the side surfaces at both ends and the side surfaces of the intermediate portions of the rare earth magnets 10A and 10B are also adhered to the holder 1.

Table 1 below shows the results of the plating of the Nd-Fe-B magnet, the plating of the zinc die-cast, and the results after the thermal shock test.

[0034]

[Table 1] However, plating was performed with a Cu film thickness of 10 μm and a Ni film thickness of 5 μm.
m and zinc die casting, respectively.
Those having Sn plating were treated thereon so as to have a Sn film thickness of 1 μm. When using only Ni, the film thickness is 10 μm
The processing was performed so that

In the case of Sn plating on the outermost surface, the magnet was peeled off after the thermal shock test, and the strength could not be measured.

Next, Table 2 below shows the results of plating of Nd-Fe-B-based magnets, plating of zinc die-cast, and tests after constant temperature and humidity tests.

[0037]

[Table 2]

From Table 2, it can be seen that the rust was generated in the moisture resistance test for the zinc die-casting that was not plated. In particular, the powder that had not been subjected to any treatment on the zinc die-cast had the powder blown out from the entire surface.

According to this embodiment, the following effects can be obtained.

(1) The holder 1 is formed by sequentially laminating a Cu plating layer and a Ni plating layer as a base on a zinc die-cast, so that the adhesion with the rare earth magnet can be ensured, and the adhesion after low-temperature storage. Deterioration can be suppressed and reliability can be ensured.

(2) Rare earth magnets 10A and 10B are Nd-
Fe-B based magnets are relatively inexpensive as rare earth magnets.
Further, the rare earth magnets 10A and 10B have a Ni plating layer formed on the outermost surface, so that the adhesion to the holder 1 can be secured and the moisture resistance can be improved. In addition, it is possible to generate a sufficient magnetic field necessary for the magnetic mass unit. Furthermore, if the structure of the rare earth magnets 10A and 10B is such that a Cu plating layer and a Ni plating layer are sequentially laminated as a base, the adhesiveness and moisture resistance can be further improved.

(3) When plating zinc die-casting and rare earth magnets, a Cu plating layer was
By performing a strike plating treatment of Cu using an alkali chelating bath of 7 to 10, a plating layer having good adhesion can be formed.

The Ni on the outermost surface of the holder or the rare earth magnet was
Instead of the plating layer or superimposed on the Ni plating layer, Ni-
A plating layer of a P alloy, a Ni-B alloy, or a Ni-Sn alloy may be formed. Ni-P alloys, Ni-B alloys, and Ni-Sn alloys are non-magnetic, and if these alloy plating layers are used instead of the Ni plating layers, a decrease in surface magnetic flux density due to the magnetic plating layers can be avoided, This is particularly effective when the rare earth magnet is small and thin.

Further, a Cu plating layer as a base is formed by plating continuously in a weak alkali chelating bath of pH 7 to 10 using an organic chelating agent until a sufficient film thickness is reached, and formed by a copper pyrophosphate bath. The plating process can be omitted. However, it is disadvantageous in cost as compared with the case where the plating treatment of the copper pyrophosphate bath is used in combination.

Although the embodiments of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited to the embodiments and that various modifications and changes can be made within the scope of the claims. There will be.

[0046]

As described above, according to the present invention,
It is possible to improve the adhesiveness and moisture resistance between the zinc die-casting holder and the rare earth magnet, and in particular, to suppress the adhesive deterioration after low-temperature storage and achieve excellent reliability.

[Brief description of the drawings]

FIG. 1 is an exploded view of a magnetic motion mass part for a mobile communication device and a method of manufacturing the same according to the embodiment of the present invention, before a rare earth magnet is bonded to a holder.

FIG. 2 is a front view after the bonding of the rare-earth magnet.

FIG. 3 is a plan view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Holder 2A, 2B Main surface 3A, 3B End side wall 4A, 4B Intermediate side wall 10A, 10B Rare earth magnet

Continued on front page F term (reference) 4K024 AA03 AA09 AA15 AA23 AB02 AB03 BA01 BB14 BC10 DA09 GA01 GA16 5D107 AA09 AA10 BB08 CC09 FF20 5E040 AA04 AA19 BC01 BC08 BD01 CA01 HB00 HB14 NN17

Claims (5)

[Claims] 1. A magnetic motion mass part for a mobile communication device in which a rare earth magnet is bonded to a holding body, wherein the holding body is made of zinc die-cast, a Cu plating layer as a base, Ni, Ni-P alloy, Ni-B. Alloy, Ni
A magnetic kinetic mass part for mobile communication equipment, characterized in that any one or more plating layers of an Sn alloy are sequentially laminated. 2. The rare earth magnet is an Nd—Fe—B based magnet, and Ni, Ni—P alloy, Ni—B alloy,
The magnetic kinetic mass section for a mobile communication device according to claim 1, wherein any one of a plating layer of a Ni-Sn alloy is formed. 3. The magnetic motion mass unit for mobile communication equipment according to claim 2, wherein the Nd—Fe—B-based magnet has a Cu plating layer as a base of the plating layer on the outermost surface. 4. After forming a Cu plating layer as a base on a zinc die-cast, Ni, Ni—P alloy, Ni—B alloy, N
a holder forming step of forming a holder by laminating any one or more plating layers of an i-Sn alloy; and a Ni, Ni-P alloy, Ni-B on the outermost surface of the rare earth magnet.
Alloy, a surface treatment step of a rare earth magnet for forming a plating layer of any one of a Ni—Sn alloy, and a fixing step of fixing the rare earth magnet after the surface treatment step to the holder with an adhesive. A method for manufacturing a magnetic motion mass unit for mobile communication equipment. 5. The method according to claim 4, wherein the Cu plating layer as the base is treated at least initially using an alkali chelate bath having a pH of 7 to 10.