JPH09293338A - Manufacture of member for head positioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a member for a head positioning device having high dimensional accuracy and being made of a thermoplastic resin. SOLUTION: In this method, members for a head positioning device integrally infection-molding members 1 with carriage sections 3 and a plurality of arm sections 4 simultaneously by the molding material of a thermoplastic resin are manufactured. The molding material is infected from a gate not directly coupled with cavity sections, from which arm sections 4 are molded, and the members 1 for the positioning device are injected to mold together with specified removing sections 2 connected in the longitudinal direction of the arm sections 4 through narrow sections 5 to the front ends of each arm section 4 respectively. Relative places among each removing section of a molded form acquired by the injection molding are fixed and the molded form is annealed, and the removing sections are removed from the molded form after the annealing and the members for the head positioning device are obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a head positioning device of a disk drive device for recording / reproducing information, and has a carriage part and an arm part, and is excellent in dimensional accuracy. Regarding the method. This member is used, for example, in an oscillating head positioning device of a hard disk device, and is excellent in dimensional accuracy, dimensional stability, dimensional adjustment flexibility, and the like.

[0002]

2. Description of the Related Art A head positioning device used in a disk drive device for storing or retrieving information, which is represented by a hard disk drive device, an optical disk drive device, a floppy disk device, etc., conventionally uses a metal material as a main raw material. Being manufactured. However, in recent years, due to demands for space saving, weight saving, labor saving in the assembly process, etc., use of an engineering plastic having high rigidity and capable of precision molding has been proposed.

For example, regarding application of a thermoplastic resin member to an oscillating type head positioning device used in a hard disk device, JP-A-61-104376 discloses use of a fiber reinforced thermoplastic resin, JP-A-63. Japanese Patent Publication No. 99756 discloses the use of a thermoplastic resin filled with metal powder.
No. 9062 discloses a tensile elastic modulus of 300,000 Kg / c.
Use of thermoplastic resin of m ² or more, and US Pat.
82,851 propose the use of a thermoplastic resin arm with a metal pad.

Regarding the carriage portion used in the disk drive, Japanese Patent Laid-Open No. 63-136364 describes the use of an inorganic filler-containing liquid crystal polymer in Japanese Patent Laid-Open No. 6-17.
The 6427 publication proposes the use of polyetheretherketone.

[0005]

However, these publications only describe the effects obtained when the characteristics of the engineering plastic having high rigidity and capable of precision molding are sufficiently exerted. Despite the widespread acceptance of thermoplastic resins that their material properties can vary greatly depending on the molding method, these publications disclose the required size of the molding method. There is no specific disclosure as to whether or not a molded product satisfying the precision is obtained and the required properties are exhibited.

In recent years, due to the above-mentioned demands for space saving, weight saving, and labor saving in the assembly process for the main body of the disk drive device, the head positioning device is mainly formed by integrating and integrating the parts. Is in progress.

For example, a magnetic disk, a magneto-optical disk,
In an oscillating head positioning actuator used for a hard disk such as an optical disk, a rotary carriage that constitutes an oscillating center (rotation center) and a functional member that exerts a magnetic or optical reading or writing function at one end ( A member having a shape in which a head arm on which a head is installed is integrated (usually, a head suspension is further interposed to hold the head). Here, although the rotary carriage may be made of resin, the head arm is actually a metal plate in many cases. The reason for this is
In the molding of the head arm by simple resin injection molding,
This is because the long and plate-shaped head arm portion is likely to be deformed (warp, twist, etc.), and as a member of the head positioning device, accuracy such as dimensional accuracy may be insufficient. Since the position of the head is directly determined by the head arm, it is natural that the accuracy of the arm accuracy is particularly high in the head positioning device.

Therefore, there is a need for a member for a thermoplastic resin head positioning device that overcomes the technical problem of dimensional accuracy more than ever, and an object of the present invention is to provide such a member.

[0009]

To achieve this object, according to the present invention, a portion of a member for head positioning device (hereinafter, simply referred to as "carriage") and a portion of a head arm (hereinafter, simply referred to as "carriage"). Although it is an integral part of the "arm"), these parts are injection-molded into a specific shape simultaneously and integrally, and the part with a large residual stress generated near the gate and the flow head part on the opposite side to By arranging it in the part of the arm or the part that is removed after molding, it is possible to suppress the residual molding strain in the arm as much as possible and control the resin flow to improve the uniformity and rigidity of the members that make up the arm. High,
Therefore, the dimensional accuracy of the arm is improved. Further, by fixing the relative position between the removed portions and performing annealing, the dimensional accuracy is further improved, and the stability of the dimensional accuracy and the flexibility of the dimensional adjustment are excellent.

More specifically, the manufacturing method of the present invention is used for a head positioning device of a disk drive device for recording / reproducing information, wherein a member having a carriage portion and a plurality of arm portions is made of a thermoplastic material. A method of manufacturing a member for a head positioning device, which is integrally and simultaneously injection-molded with a resin molding material, wherein the molding material is injected from a gate that is not directly connected to the cavity portion for molding the arm portion, and the tip of each arm portion is injected. On the other hand, a positioning device member is injection-molded together with a predetermined removal portion connected in the longitudinal direction of the arm portion via a narrow portion, and the relative position between the respective removal portions of the molded product obtained by this injection molding is fixed. Anneal the molding, and after this anneal
The member for head positioning device is obtained by removing the removed portion from the molded product.

The injection of the molding material is carried out, for example, through a gate set so that the filling of the molding material is completed in the cavity portion for molding any of the removed portions.
The filling of the molding material preferably ends with leaving an unfilled part in the cavity part forming the at least one removal part.

Each of the removed portions has a volume not more than 1/2 and not less than 1/4 of the arm portion to which it is connected, and the cross section perpendicular to the longitudinal direction is the same as the cross section of the arm portion. It preferably has a similar or similar shape.

The thermoplastic resin used as the molding material contains a fibrous filler and has a tensile modulus of elasticity of 100 after solidification.
It is preferably 000 kg / cm ² or more. As such a thermoplastic resin, for example, a thermotropic liquid crystal polymer can be used.

Further, a cylindrical insert member fitted to a shaft for swingably supporting the carriage portion may be inserted at the time of injection molding. The disk drive device is, for example, a magnetic, optical / magnetic, or optical disk hard disk drive device, and the head positioning device is, for example, an oscillating actuator.

[0015]

1 is a plan view of a molded product including a head positioning device member 1 for a hard disk drive device and a removed portion 2 according to an embodiment of the present invention.
FIG. 2 is a side view thereof. The member 1 is one in which a carriage 3 and three arms 4 are integrally and simultaneously injection-molded, and the arm 4 has little weld line or the like due to the merging of the flow ends of the molten resin or turbulent flow due to the collision of the flow ends. . The removed portion 2 is connected to the tip of each arm 4 via the narrow portion 5 and is located on an extension line of the arm 4 in the longitudinal direction. Reference numeral 6 in FIG. 1 is a hole for mounting the head. The removed portion 2 and the narrow portion 5 are different from any of the gate, the sprue, and the runner, and these gates and the like are provided separately. Further, R is provided at a joint portion between the arm 4 and the carriage 3 as needed so that dimensional accuracy can be easily obtained.

The injection molding is carried out by injecting a thermoplastic resin molding material into a mold through a gate that is not directly connected to a cavity for molding the arm 4. Here, the carriage 3
Injecting in the direction of arrow A from the end of the portion (of the cavity for molding) opposite to the arm 4, or removing each removal portion 2
It is injected in the direction of arrow B from the end opposite to the narrow portion 5 of the part.

When resin is injected in the direction of arrow A from the end of the carriage 3 part, the removed part 2 part is replaced by the arm 4 part.
It has a function as a resin reservoir of a thermoplastic resin that flows in the longitudinal direction. As a result, the tip (flow front) of the flowing resin does not collide with the mold wall in the flow direction in the arm 4 portion and is not solidified in the arm 4 portion in a turbulent state. After passing through the arm 4 part, the flow head collides with the mold wall and solidifies in the removal part 2 part. Therefore, it is possible to prevent the solidified portion of the flow front having a large residual strain from occurring in the arm 4 portion, and to maintain the uniformity of the resin flow in the arm 4 portion. According to this, the mechanical characteristics of the arm 4 can be made uniform, and the warp and twist of the arm 4 can be suppressed to improve the dimensional accuracy.

When the resin is injected in the direction of arrow B from the end of each removed portion 2 unlike the above injection direction, the resin injected from the gate inevitably passes through each removed portion 2 and then the arm 4 portion. Flow into. Therefore, a portion having a residual strain near the gate (inflow portion from the gate) exists in the removed portion 2 and does not exist in the arm 4. Further, since the resin flowing into the arm 4 portion further flows into the carriage 3 portion without staying there, the flow front does not collide with the mold wall and solidify in the arm 4 portion.
The flow head collides with and solidifies in the carriage 3. Therefore, also in this case, it is possible to avoid the collision / solidification portion of the flow head having a large residual strain in the arm 4, and it is possible to maintain the uniformity of the resin flow in the arm 4 portion. The arm 4 having uniform mechanical characteristics and excellent dimensional accuracy can be obtained.

When the resin is injected in the direction of arrow B from the end of each removed portion 2 in the case of injection from the above B direction, a common runner is inevitably connected to each removed portion 2. Therefore, due to a small volume of the removed portion 2 or the like, there is a possibility that a dimensional change due to molding shrinkage or the like during the solidification process of the runner may affect the dimensional accuracy of the arm 4, or the arm 4 may warp or twist. Sometimes there is. In such a case, it is preferable that after removing the molded product from the mold, the gate portion is immediately cut to separate the runner and the removed portion 2.

In either case of ejecting from the A direction or the B direction, it is not preferable that the removed portions 2 are directly connected to each other or common to the arms 4. This is to prevent dimensional changes due to molding shrinkage or the like in the solidification process of the removed portion 2 from deteriorating the dimensional accuracy between the arms 4 or causing the arms 4 to warp or twist. However, this does not apply when the removed portion 2 satisfies a specific condition such as a large volume ratio to the arm 4 as described later.

The narrow portion 5 may be of any shape as long as it has the above-mentioned effect, that is, avoiding the collision of the flow head in the arm 4 and the occurrence of a solidified portion, and ensuring the uniformity of the resin flow state. That is, due to the existence of the narrow portion 5, for example, A
When the resin is injected from the direction, the resin that is sequentially filled from the carriage 3 to the arm 4 portion is once throttled in the resin flow in the narrow portion 5, so that the inflowing resin is sufficiently supplied to the arm 4
The inside of the cavity forming the portion will be filled. Therefore, it is difficult to ensure the uniformity of the flow state of the resin in the narrow portion which is too narrow, which is not preferable. Therefore,
For example, the cross-sectional area of the narrow portion 5 is generally smaller than the cross-sectional area of the tip of the arm 4, but it is preferable that it is up to 1/10 at the smallest. Further, in order to sufficiently exert this effect, the width W1 of the narrow portion 5 is 100% or less and 30% or more, preferably 50% or more of the width W2 of the end portion of the removed portion 2 adjacent to the narrow portion 5. It is preferably 70% or more, 100% or less of the width W3 of the arm 4 end, 30% or more, preferably 50% or more, and more preferably 70% or more.

The hole 6 for mounting the head is reinforced by an insert member by being inserted at the time of injection molding if necessary. There are various methods for attaching the head to the hole 6, but for example, a metal protrusion having a hollow hole fixed to a head suspension holding a magnetic head is inserted into the hole 6, and the hollow hole is The head suspension and the arm 4 are integrally connected by pressurizing and expanding the inner wall. At this time, if there is a turbulent flow portion or weld line formed by the flow head colliding near the hole 6 and solidifying, that portion may be cleaved. In the vicinity of 6, the weld line does not exist, so that the vicinity of the hole 6 is not cleaved. Further, as described above, since the arm 4 does not have a portion having a large residual stress such as a weld line or a gate mark, excellent characteristics can be imparted to the member 1 for positioning the head.

The molded product obtained by injection molding is annealed while fixing the relative position between the removed parts 2, and after this annealing treatment, the removed part 2 is removed from the molded product and the head is removed. The positioning device member 1 is obtained.

Prior to this annealing process, FIG.
FIG. 6 is a plan view showing a state in which the relative positions between the respective removed portions 2 are fixed by a jig 8, and FIG. 5 is a view of the jig 8 seen from the direction of arrow 9. As shown in FIG. 5, the jig 8 is provided with three openings 11, and the openings 11 match the shape of the cross section (FIG. 6) of the removed portion 2 taken along the line BB. In order to fix the relative position between the removed portions 2 with the jig 8, the
, The jig 8 is moved in the direction of arrow 10,
It suffices to fit each removed portion 2. FIG. 4 is a side view showing a state in which the relative position between the removed portions 2 is fixed by the jig 8. FIG. 7 is a sectional view taken along the line CC of FIG. CC line is Fig. 3
Coincides with the BB line. The fitted jig 8 is a BB line (CC
Located on the line) to fix between the removed portions 2 and maintain the dimensional accuracy between the removed portions 2 extremely excellent. Further, since the fitting is strong, the occurrence of dimensional deviation due to the loosening of the jig 8 can be suppressed. Further, the adjustment of the relative distance between the arms 4, which was conventionally performed by modifying the mold, can be easily performed by changing the distance D between the openings 11.

The annealing treatment mainly aims at relaxing residual stress and promoting crystallization, and has the purpose of preventing dimensional change of the member 1 during long-term use. The conditions of the annealing treatment (temperature, time, equipment used, etc.) differ depending on the thermoplastic resin used as the molding material, but the conditions that can achieve the above object may be selected according to known techniques. In addition, as described above, the fixing between the removed portions 2 is performed by the jig 8 after molding.
Although it is simple and preferable to perform the fitting by fitting it to the removed portion 2, the jig may be inserted and fixed at the time of injection molding.

The temperature in the heat treatment is any temperature above room temperature and up to the heat distortion temperature of the resin. Preferably, the temperature is higher than the mold temperature, and is higher than the mold temperature by 1
It is a temperature range of not higher than 00 ° C.

The heating means may be simple and can be usually an air bath using an appropriate oven.
It is also possible to use a liquid bath in which a solvent inert to the resin is used. The heating time is appropriately determined in consideration of changes in physical properties such as dimensions, but normally requires 10 minutes to 5 hours. Generally, the heating time can be shortened in the liquid bath as compared with the air bath.

Since the molecules of the arm thus obtained are oriented as described above, the coefficient of linear expansion of the arm is close to that of a metal. That is, since the resin molecules are injection-molded from the tip of each arm, the resin molecules are oriented in the longitudinal direction of the arm, and the coefficient of linear expansion in this direction is smaller than the coefficient of linear expansion in the width direction (right angle direction). . This tendency is remarkable in the thermotropic liquid crystal polymer, and in this liquid crystal polymer, the coefficient of linear expansion in the longitudinal direction of the arm portion is particularly small for a resin, which is close to that of a metal. A small coefficient of linear expansion leads to a high dimensional accuracy, and the dimensional accuracy of the arm of the actuator is important in the longitudinal direction. Therefore, a high dimensional accuracy in the longitudinal direction is particularly advantageous. Therefore, when the actuator is configured by this arm, the dimensional accuracy with respect to the metal portion is high and the rigidity is also high.

As described above, the annealing process is performed by the jig 8
Fixing the removed portion 2 in step 1 has the following advantages.

Since it is possible to avoid directly attaching the jig to the arm 4 or the carriage 3, it is possible to prevent the arm 4 or the carriage 3 from being deformed or scratched due to the stress when the jig is attached or detached. Can be avoided. In addition, this effect is obtained by removing the removed portion 2 while the removed portion 2 is fixed by the jig 8.
Can be made even larger by excising.

Further, since both ends of the arm 4 are fixed by the connecting portion with the carriage 3 and the narrow portion 5 connected to the removal portion 2, uniform stress is applied to the entire arm 4. In order to fully exert this effect, the width W1 of the narrow portion 5 is 100% or less and 30% or more of the width W2 of the end portion of the removed portion 2 adjacent to the narrow portion 5, preferably 50 or more.
% Or more, more preferably 70% or more, and 100% or less of the width W3 of the end portion of the arm 4 30% or more, preferably 50.
% Or more, and more preferably 70% or more.

Further, since the removed portion 2 is finally removed together with the narrow portion 5 if necessary, the jig 8 can be firmly fixed to the removed portion 2, and the dimension caused by the displacement of the jig 8 can be achieved. No error occurs. When the arm 4 or the like is fixed, the arm may be deformed. Also, the removed portion 2
By freely changing the shape of, the degree of freedom in selecting jigs can be expanded.

Furthermore, since the jig 8 fixes the removed portion 2, it is possible to substantially ignore factors that affect the dimensional accuracy of the arm 4, such as thermal expansion and heat conduction of the jig 8. it can. Therefore, there is no limitation on the material of the jig 8, and any metal, synthetic resin, ceramics or the like may be used as long as it can be formed into a shape required for fixing. Of these, engineering plastics are preferable from the viewpoints of heat resistance, freedom of shape, lightness, rigidity, dimensional accuracy, and the like.

By the way, when the resin is injected from the end of the carriage 3 in the direction of arrow A, the filling of the resin into the mold is completed at the removed portion 2. At that time, the resin is filled in the order of the carriage 3, the arm 4, and the removed portion 2. Therefore, the resin flows from the carriage 3 portion to the arm 4 portion with little disturbance. Therefore, a more uniform and excellent member 1 can be obtained.

Further, when resin is injected from the end of the carriage 3 in the direction of arrow A, at least one of the removed portions 2 has an unfilled portion, so that residual strain is also caused in the removed portion 2. Can be substantially prevented, and in this case, the arm 4 naturally has a small residual strain. Therefore, generation of residual stress in the arm 4 can be prevented more effectively, and a more excellent member 1 can be obtained.

The volume of each removed portion 2 is not more than 1/2 and not less than 1/4 of the volume of the arm 4 to which it is connected, and is perpendicular to the length direction of the arm 4 of each removed portion 2. The cross-sectional shape preferably has the same, similar or similar shape as the cross section of the connecting arms 4. In this case, when resin is injected from the end of the carriage 3 portion in the direction of arrow A, the resin flowing from the carriage 3 portion into the arm 4 portion flows more quickly from the arm 4 portion tip to the removed portion 2 portion, The resin is filled in the arm 4 portion with less disorder. Further, the influence of residual strain on the arm 4 in the vicinity of the narrow portion 5 and the final portion of resin filling (the portion where the flow head collides with the mold wall in the flow direction and solidifies) can be made extremely small. Thereby, the more uniform and excellent member 1 can be obtained.

The thermoplastic resin used as a molding material contains a fibrous filler and has a tensile elastic modulus of 100,000 kg / cm ² or more when solidified. When this resin is poured into the mold, the direction of the resin flow in the arm 4 portion matches the length direction of the arm 4, so the synergistic effect of the orientation of the fibrous substance in the resin and the tensile elastic modulus of the resin. As a result, the elastic modulus of the arm 4 in the lengthwise direction can be increased, and a more excellent member 1 can be obtained. Examples of thermoplastic resins and fibrous fillers that can be combined include, for example, thermoplastic resins, polyamide resins, polyacetal resins, polycarbonate resins, modified polyoxide resins, polybutylene terephthalate resins, polyethylene terephthalate resins, polyphenylene sulfide resins, polysulfone resins, Engineering plastics such as polyarylate resins, thermotropic liquid crystal polymer resins, polyether resins, and polyimide resins can be used as the fiber filler, and glass fibers, carbon fibers, various whiskers, and the like can be given.

Among these thermoplastic resins, it is preferable to use thermotropic liquid crystal polymer resin in order to improve the elastic modulus and mechanical strength. Although the reason is not clear, it is considered that the characteristic is that the apparent viscosity does not change significantly even when the liquid crystal polymer flows from the arm 4 portion to the narrow portion 5 portion.

As the molding material, a thermotropic liquid crystal polymer having excellent heat resistance and dimensional stability, preferably a thermotropic liquid crystal polyester resin is used. A thermotropic liquid crystal polymer is a meltable polymer that exhibits optical anisotropy when melted and is thermoplastic. As described above, the polymer exhibiting optical anisotropy when melted has a property that the polymer molecular chains have a regular parallel arrangement in the melted state. The properties of the optically anisotropic molten phase can be confirmed by a usual polarization inspection method using a crossed polarizer.

Examples of the above-mentioned liquid crystal polymer include liquid crystal polyester, liquid crystal polycarbonate, liquid crystal polyester imide and the like, specifically, (all) aromatic polyester, polyester amide, polyamide imide, polyester carbonate, polyazomethine and the like. Can be mentioned.

The thermotropic liquid crystal polymer is generally composed of an elongated and flat molecular structure, has high rigidity along the long chain of the molecule, and has a plurality of chain extension bonds in a coaxial or parallel relationship. .

In the thermotropic liquid crystal polymer used in the present embodiment, a part of one polymer chain is composed of polymer segments forming an anisotropic melt phase, and the remaining part does not form an anisotropic melt phase. Also included are polymers composed of polymer segments. Further, it also includes a composite of a plurality of thermotropic liquid crystal polymers.

Typical examples of the monomer constituting the thermotropic liquid crystal polymer include (a) at least one aromatic dicarboxylic acid, (b) at least one aromatic hydroxycarboxylic acid compound, and (c) aromatic diol compound. At least one compound, (d) (d ₁ ) aromatic dithiol, (d ₂ ) aromatic thiophenol, (d ₃ ) at least one aromatic thiol compound, (e) aromatic hydroxyamine , At least one of aromatic diamine compounds, and the like. Although these may be configured independently, in most cases, (a) and (c), (a) and (d), (a)
(B) and (c), (a), (b) and (e), or (a), (b), (c) and (e) and the like.

As the above-mentioned (a) aromatic dicarboxylic acid type compound, terephthalic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-triphenyldicarboxylic acid, 2,6-
Naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, diphenoxybutane-4,
4'-dicarboxylic acid, diphenylethane-4,4'-dicarboxylic acid, isophthalic acid, diphenylether-3,
3'-dicarboxylic acid, diphenoxyethane-3,3'-
Aromatic dicarboxylic acids such as dicarboxylic acid, diphenylethane-3,3'-dicarboxylic acid, 1,6-naphthalenedicarboxylic acid or chloroterephthalic acid, dichloroterephthalic acid, bromoterephthalic acid, methylterephthalic acid,
Examples thereof include alkyl, alkoxy or halogen substitution products of the above aromatic dicarboxylic acids such as dimethyl terephthalic acid, ethyl terephthalic acid, methoxy terephthalic acid and ethoxy terephthalic acid.

Examples of the aromatic hydroxycarboxylic acid compound (b) include aromatic hydroxy such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid and 6-hydroxy-1-naphthoic acid. Carboxylic acid or 3-methyl-4-hydroxybenzoic acid, 3,5
-Dimethyl-4-hydroxybenzoic acid, 2,6-dimethyl-4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3,5-dimethoxy-4-hydroxybenzoic acid, 6-hydroxy-5-methyl -2-naphthoic acid, 6-hydroxy-5-methoxy-2-naphthoic acid,
2-chloro-4-hydroxybenzoic acid, 3-chloro-4
-Hydroxybenzoic acid, 2,3-dichloro-4-hydroxybenzoic acid, 3,5-dichloro-4-hydroxybenzoic acid, 2,5-dichloro-4-hydroxybenzoic acid, 3
-Bromo-4-hydroxybenzoic acid, 6-hydroxy-5
-Alkyl, alkoxy or halogen substitution products of aromatic hydroxycarboxylic acids such as -chloro-2-naphthoic acid, 6-hydroxy-7-chloro-2-naphthoic acid and 6-hydroxy-5,7-dichloro-2-naphthoic acid Is mentioned.

As the aromatic diol (c), 4,4 '
-Dihydroxydiphenyl, 3,3'-dihydroxydiphenyl, 4,4'-dihydroxytriphenyl, hydroquinone, resorcin, 2,6-naphthalenediol, 4,4'-dihydroxydiphenyl ether, bis (4-hydroxyphenoxy) ethane, 3 , 3'-dihydroxydiphenyl ether, 1,6-naphthalenediole, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane and other aromatic diols or chlorohydroquinone Alkyl, alkoxy or halogen substitution products of aromatic diols such as methyl hydroquinone, t-butyl hydroquinone, phenyl hydroquinone, methoxy hydroquinone, phenoxy hydroquinone, 4-chlororesorcin, 4-methylresorcin and the like.

Examples of (d ₁ ) aromatic dithiol include benzene-1,4-dithiol, benzene-1,3-dithiol, 2,6-naphthalene-dithiol and 2,7-naphthalene-dithio. -Ru and the like. Examples of (d ₂ ) aromatic thiophenol include 4-mercaptophenol and 3
-Mercaptophenol, 6-mercaptophenol and the like. Examples of (d ₃ ) aromatic thiol carboxylic acid include 4-mercaptobenzoic acid, 3-mercaptobenzoic acid, 6-mercapto-2-naphthoic acid and 7-mercapto-2-naphthoic acid.

(E) As aromatic hydroxyamine and aromatic diamine compounds, 4-aminophenol and N-
Methyl-4-aminophenol, 1,4-phenylenediamine, N-methyl-1,4-phenylenediamine,
N, N'-dimethyl-1,4-phenylenediamine, 3
-Aminophenol, 3-methyl-4-aminopheno-
2-chloro-4-aminophenol, 4-amino-
1-naphthol, 4-amino-4'-hydroxydiphenyl, 4-amino-4'-hydroxydiphenylether, 4-amino-4'-hydroxydiphenylmethane,
4-amino-4′-hydroxydiphenyl sulfide,
4,4′-diaminophenyl sulfide (thiodianiline), 4,4′diaminodiphenyl sulfone, 2,5-
Diaminotoluene, 4,4'-ethylenedianiline,
4,4'-diaminodiphenoxyethane, 4,4'-diaminodiphenylmethane (methylenedianiline), 4,
4'-diaminodiphenyl ether (oxydianiline) and the like can be mentioned.

The thermotropic liquid crystal polymer used in this embodiment can be produced from the above-mentioned monomers by various ester forming methods such as a melt acidolysis method and a slurry polymerization method.

The thermotropic liquid crystal polyester which can be used in this embodiment and has a preferable molecular weight is about 2000 to 2000.
00, preferably about 4000 to 100,000. The molecular weight can be measured, for example, by measuring the terminal groups of the compressed film by infrared spectroscopy. It is also possible to use gas permeation chromatography (GPC), which is a general measurement method involving solution formation.

Among the thermotropic liquid crystal polymers obtained from these monomers, aromatic polyesters which are (co) polymers containing the monomer unit represented by the following general formula (1) as an essential component are preferable. Particularly preferred is an aromatic polyester containing 5 mol% or more of the monomer unit.

[0052]

Embedded image A particularly preferred aromatic polyester which can be used in this embodiment is a polyester represented by the following general formula (2) having repeating units each having a structure derived from three compounds of p-hydroxybenzoic acid, phthalic acid and biphenol. . The repeating unit of the structure derived from the biphenol of the polyester represented by the general formula (2) is
It may be a polyester in which a part or all of it is substituted with a repeating unit derived from dihydroxybenzene. It has repeating units with structures derived from two compounds, p-hydroxybenzoic acid and hydroxynaphthalenecarboxylic acid, respectively. A polyester represented by the following general formula (3).

[0053]

Embedded image

[0054]

Embedded image In the present embodiment, a thermotropic liquid crystal polymer using any one of the above thermotropic liquid crystal esters may be used, but it may be used as a mixture of two or more kinds. Further, the thermotropic liquid crystal polymer may be used alone, but other non-liquid crystal thermoplastic synthetic resin may be used in combination.

Here, if necessary, various additives are added to these thermotropic liquid crystal polymers.
In particular, the inorganic filler is the mechanical strength and heat resistance of the liquid crystal polymer,
It is effective in further improving the dimensional stability and the like, and can be blended in the liquid crystal polymer in an amount of about 5 to 90% by weight. Other additives include antioxidants, heat stabilizers, ultraviolet absorbers, light stabilizers, pigments, dyes, plasticizers,
Lubricants, nucleating agents, antistatic agents, flame retardants and the like can be mentioned.

Specific examples of the fibrous filler include carbon fibers (PAN-based and pitch-based), metal fibers (soft steel, stainless steel, copper and its alloys, aluminum and its alloys,
Examples thereof include lead), metallized glass fibers (glass fibers coated with nickel, copper, aluminum, silver, etc.), nickel-coated carbon fibers, and the like.

FIG. 8 is a head positioning device member 1 for a hard disk drive device according to another embodiment of the present invention.
FIG. 10 is a plan view of a molded product including the removed portion 2 and FIG. 9 is a cross-sectional view taken along the line AA of FIG. In this member 1, the carriage 3 has a cylindrical insert member 7 as shown in FIG. Other configurations are the same as those in FIG. The insert member 7 is inserted during injection molding of the member 1.

According to this, the carriage 3 after injection molding
Due to the influence of contraction, it is possible to prevent the positional displacement of the tip end portion of the arm 4 connected thereto from being spatially displaced. That is, by constructing the mounting hole 12 for swingably mounting the carriage 3 with a cylindrical insert member 7 having a closed cross-section structure excellent in bending rigidity and torsional rigidity, it is possible to reduce the influence of contraction of the carriage 3. The joint angle between the carriage 3 and the arm 4 changes and the arm 4 moves.
It is possible to prevent the spatial position of the tip from shifting.

The injection of the molding material at the time of injection molding is
By performing the operation from the upper end of the carriage 3 in the direction of arrow C, it is possible to prevent the residual stress and the nonuniform strength portion from being generated in the arm 4, as described above.

Also in this case, the advantages (1) to (3) can be obtained by fixing the removed portion 2 and performing the annealing treatment.

[0061]

As described above, according to the present invention, the molding material is injected from the gate which is not directly connected to the cavity portion for molding the arm portion, and injection molding is performed together with the removal portion, and after this molding product is solidified. Since the removed portion is removed, it is possible to suppress the generation of residual stress or a portion having uneven strength in the arm portion, and it is possible to improve the dimensional accuracy.

Further, since the relative positions of the removed parts of the molded product are fixed and the molded product is annealed before removing the removed parts, the stability and flexibility of the dimensional accuracy of the arm parts are improved. Can be made. For example, in the case of thermotropic liquid crystal resin, the mold temperature is 60 to 170.
C., preferably 60 to 130.degree. C., for example, more specifically 80.degree. C., 120.degree. In this case, the heat treatment temperature was 100 ° C. (mold 80 ° C.), 140 ° C. (mold 80 ° C. or 120 ° C.), and the heating time was 1 hour for each heat treatment. Further, it is possible to avoid the deformation and scratches of the arm portion and the carriage portion. Also, the degree of freedom in selecting a jig for fixing can be improved. In addition, since it can be firmly fixed, the dimensional accuracy of the arm portion can be further improved.

Further, since the injection of the molding material is performed through the gate which is set so that the filling of the molding material is completed in the cavity portion for molding the removed portion, residual stress and strength are nonuniform in the carriage portion as well. It is possible to suppress the occurrence of a large portion.

Further, by ending the filling of the molding material with the unfilled portion left in the cavity portion for molding the removed portion, residual stress in the arm portion and a portion having uneven strength are generated. It can be further suppressed.

The removed portion has a volume not more than ½ and not less than ¼ of the arm portion to which it is connected, and the cross section perpendicular to the longitudinal direction of the arm portion is the cross section of the arm portion. By having the same shape, similar shape, or similar shape, it is possible to further suppress the occurrence of a residual stress in the arm portion or a portion having uneven strength.

A thermoplastic resin as a molding material contains a fibrous filler and has a tensile elastic modulus of 1 after solidification.
By using one having a weight of at least 0,000 kg / cm ^2, the elastic modulus in the longitudinal direction of the arm portion can be synergistically improved.

By using a liquid crystal polymer as the thermoplastic resin, this synergistic effect can be further enhanced.

Also, by inserting a cylindrical insert member into the carriage portion during injection molding, it is possible to suppress adverse effects on the dimensional accuracy of the arm portion due to molding contraction of the carriage portion.

Further, by applying the positioning device member according to the present invention to the swing actuator of the head positioning device of the hard disk drive device, the positioning accuracy and speed can be improved.

Further, even though the carriage part and the arm part are integrally and simultaneously injection-molded, the arm part has neither a flow-head part of the molding material nor an inflow part from the gate. It is possible to provide a member for a head positioning device having high uniformity of accuracy and strength.

[Brief description of drawings]

FIG. 1 is a plan view of a molded product including a head positioning device member 1 and a deleted portion 2 for a hard disk drive device according to an embodiment of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a plan view showing a state in which a relative position between respective removed portions is fixed by a jig.

FIG. 4 is a side view showing a state in which a relative position between respective removed portions is fixed by a jig.

FIG. 5 is a view of the jig as seen from the direction of arrow 9.

6 is a cross-sectional view taken along the line BB of FIG.

FIG. 7 is a sectional view taken along line CC of FIG.

FIG. 8 is a plan view of a molded product including a head positioning device member 1 and a deleted portion 2 for a hard disk drive device according to another embodiment of the present invention.

9 is a side view taken along the line AA of FIG.

10 is a perspective view of an insert member of the molding of FIGS. 8 and 9. FIG.

[Explanation of symbols]

1: Head positioning device member, 2: Deleted part, 3: Carriage, 4: Arm, 5: Narrow part, 6: Head mounting hole, 7: Insert member, 8: Jig, 11: Opening part, 1
2: Mounting hole.

Claims (8)

[Claims] 1. A member used for a head positioning device of a disk drive device for recording / reproducing information and having a carriage part and a plurality of arm parts is integrally and simultaneously injection molded by a molding material of a thermoplastic resin. A method of manufacturing a member for a head positioning device, comprising injecting a molding material from a gate that is not directly connected to a cavity portion for molding the arm portion, and inserting a molding material into a tip portion of each arm portion in a longitudinal direction of the arm portion through a narrow portion. The positioning device member is injection-molded together with the predetermined removed portions connected to each other, the relative position between the removed portions of the molded article obtained by this injection molding is fixed, and the molded article is annealed. After that, the removed portion is removed from the molded product to obtain a head positioning device member. Method of manufacturing wood. 2. The injection of the molding material is performed through a gate set so that the filling of the molding material is completed in any of the cavity portions for molding any of the removed portions. Production method. 3. The filling of the molding material ends with leaving an unfilled portion in a cavity portion forming at least one of the removed portions.
The manufacturing method as described. 4. Each removed portion has a volume of ½ or less and ¼ or more of an arm portion to which it is connected, and a cross section perpendicular to the longitudinal direction is a cross section of the arm portion. The manufacturing method according to claim 1, wherein the manufacturing method has the same shape, a similar shape, or a similar shape. 5. The thermoplastic resin contains a fibrous filler and has a tensile elastic modulus after solidification of 100,000 kg / c.
The process according to any one claims 1 to 4, characterized in that m ² or more. 6. The method according to claim 1, wherein the thermoplastic resin is a liquid crystal polymer. 7. The manufacturing method according to claim 1, wherein a cylindrical insert member that fits on a rotating shaft that is swingably attached to the carriage portion is inserted during the injection molding. Method. 8. The manufacturing method according to claim 1, wherein the disk drive device is a hard disk drive device, and the head positioning device is an oscillating actuator.