JP4390150B2 - Resin bearing parts and manufacturing method thereof - Google Patents

Description

  The present invention relates to a resin bearing part that engages and supports the shaft part so that the shaft part is fitted in the shaft hole of the resin bearing part, and both can rotate or slide or slide and rotate relative to each other. This is particularly suitable for resin bearing parts that require high-precision rotation or sliding or sliding rotation and a method for manufacturing the same.

  This type of resin bearing parts is light and has low inertia, mass production, etc., and so on, from general bearing parts including gears and cams, sensors, potentiometers, actuators, etc. Widely used in bearings for precision parts.

  Among these high precision components, for example, in the case of a bearing portion in a lens holder that performs optical pickup with an optical information recording / reproducing apparatus, precise roundness and inner diameter dimensional accuracy are required, and clearance from the shaft is required. Is required to be several μm or less, and high mechanical strength and slidability with respect to a load are also required.

  However, when an injection-molded resin bearing part is used as it is, precision roundness and inner diameter dimensional accuracy cannot be obtained due to heat shrinkage and orientation, and the mechanical strength is lowered by the weld line. A sleeve made of an aluminum alloy or the like was attached to the inner peripheral surface of the resin, or a lubricating resin pipe was insert molded.

  However, when using a sleeve made of an aluminum alloy or a lubrication resin pipe, it is necessary to perform precise cutting and polishing in order to obtain precise roundness and dimensional accuracy, resulting in high costs. At the same time, there is a problem that needs to be solved, such as a decrease in productivity.

  Therefore, the present invention proposes a resin bearing part and a method for manufacturing the same that can solve the problems of the prior art. However, a cylindrical electroformed part is integrally formed with an insert mold on the inner peripheral surface of the shaft hole of the resin bearing part. The resin bearing component and the manufacturing method thereof are particularly suitable for a bearing portion that requires high-precision rotation or sliding or sliding rotation.

In the resin bearing part according to the present invention, the cylindrical electroformed part is integrally formed with the resin molded part by insert molding, and the electroformed part is separated from the master shaft that fits the shaft hole of the bearing part after insert molding. A shaft hole inner peripheral surface having a dimensional accuracy adapted to the outer peripheral surface of the master shaft is provided . (Claim 1).

The method of manufacturing a resin bearing part according to the present invention includes a step of producing an electroformed shaft having a cylindrical electroformed part provided on the outer periphery of a master shaft that fits the shaft hole of the bearing part, and the electroformed shaft is formed into a mold. A process of making a resin molded product with an electroformed shaft inserted and mounting it inside, separating the master shaft from this resin molded product, and forming a cylindrical electroformed part which is an electroformed shell in the shaft hole And a step of forming an integrally formed bearing part.

  In the method of manufacturing a resin bearing part according to claim 2, it is possible to adopt a form in which the master shaft separated from the resin molded product is repeatedly used as a master shaft for producing an electroformed shaft. (Claim 3)

  According to the resin bearing part of claim 1, since the inner peripheral surface of the electroformed part which is an electroformed shell forms the shaft hole of the bearing part, the roundness and the inner diameter dimensional accuracy are high and the slidability is also good. Yes, there is no need for special post-processing such as polishing, and high precision rotation or sliding or sliding rotation is possible by minimizing the clearance for the shaft parts to be used by mounting on the inner peripheral surface of the electroformed part In addition, the adhesion of the resin molded part to the outer peripheral surface of the electroformed part is good.

  According to the method of manufacturing the resin bearing part of claim 2, since the injection molding is performed with the electroformed part integrated with the master shaft in the mold, the electroformed part can be easily inserted with high positioning accuracy. Since the inner peripheral surface of the electroformed part, which is an electroformed shell from which the master shaft is separated, forms the shaft hole of the bearing part, a resin bearing part having high roundness and high accuracy in the inner diameter can be obtained.

  According to the method for manufacturing a resin bearing part according to claim 3, since a large number of bearing parts can be manufactured based on the same master shaft, a homogeneous product free from variations in dimensional accuracy can be obtained economically.

  Hereinafter, the resin bearing part and the manufacturing method thereof according to the present invention will be described in detail with reference to the attached drawings of FIGS. 1 to 4 showing a preferred embodiment. As shown in FIG. Using the master shaft 1, electroforming is performed in a state where the non-electroformed portion 2 of the master shaft 1 is masked, and the electroformed shaft 4 provided with the cylindrical electroformed portion 3 is made.

  The master shaft 1 is formed of a material having high mechanical strength such as rigidity, good slidability, and excellent heat resistance and chemical resistance. However, in the illustrated embodiment, the master shaft 1 is subjected to quenching treatment. A peeled shaft made of stainless steel is used, and SUS420J is particularly desirable among stainless steels.

  The material of the master shaft 1 is not limited to stainless steel, and other materials capable of processing the electroformed part 3 and separating the electroforming can be used with the same performance. For example, nickel chrome It is also possible to use a hard metal material such as steel or other nickel alloy or chromium alloy, or a ceramic surface provided with a hard metal film.

  The shape of the master shaft 1 can be not only a peeled shaft but also a hollow shaft or a solid shaft in which a resin material is embedded in the hollow portion. When the resin bearing part is a sliding shaft, If the cross section is constant, there are polygonal shapes and other non-circular shapes. Further, depending on the application of the resin bearing component, it is possible to adopt a shape that does not have a constant cross sectional shape over the entire length of the shaft.

  The masking of the non-electroformed part 2 is performed by performing resist casting or silk-printing an ink containing an insulating material, and attaching an acid-resistant and non-conductive coating material to the outer peripheral surface of the non-electroformed part 2 and performing an electroforming process. At this time, a protective film is formed which acts only on the electroformed part 3 of the master shaft 1.

  Various types of electroformed metal can be used for the electroformed part 3 in the same manner as known electroforming. However, in the illustrated embodiment, the same stainless steel as the master shaft 1 is used, and separation from the master shaft 1 is performed. In order to facilitate, a sliding material such as carbon and a stress relaxation agent such as saccharin are included, and the thickness of the electroforming is about 0.2 to 0.3 mm.

  In addition, when the electroforming process is performed on the master shaft 1, both end sides of the electroformed part 3 protrude toward the non-electroformed part 2, and a tapered chamfered part 3a is naturally formed on the inner peripheral surface. The chamfered portion 3a is useful when the electroformed portion 3 is separated from the master shaft 1 or when the shaft component to be used is attached to and detached from the inner peripheral surface of the electroformed portion 3 of the bearing component 13.

  That is, when the electroformed part 3 is separated from the master shaft 1, for example, a high-temperature or low-temperature high-pressure air is blown to the joint portion to use the difference in thermal contraction rate between the two, or an impact is applied in the axial direction. However, the chamfered portion 3a is convenient for blowing high-pressure air, and acts as a guide when the shaft component is attached or detached.

  Next, as shown in FIG. 2, the electroformed shaft 4 is inserted in the cavity 10 of the injection mold having the upper mold 5 and the lower mold 6 instead of the core rod, and the spool 7 and the runner 8 are inserted. Then, a resin material such as liquid crystal polymer (LCP) is injected through the gate 9 to perform injection molding.

  In addition to the liquid crystal polymer (LCP), a crystalline polymer such as a polyphenylene sulfide (PPS) resin, a polyacetal resin, or a polyamide resin, or a high-functional resin material that exhibits the same function may be used as the resin material. It is possible, and an additive which becomes a fiber reinforcing agent or a lubricant may be added as necessary.

  As a result, a resin molded product 12 is obtained in which the electroformed shaft 4 and the resin molded portion 11 are integrated as shown in FIG. 3, and when the electroformed shaft 4 is pulled out from the resin molded product 12, as shown in FIG. The electroformed part 3 remains as an electroformed shell while adhering to the inner peripheral surface of the shaft hole of the resin molded part 11, and only the master shaft 1 masked on the non-electroformed part 2 is separated.

  Therefore, as shown in FIG. 4, it is possible to obtain a bearing part 13 in which the electroformed part 3 that is an electroformed shell is integrally formed on the inner peripheral surface of the shaft hole of the resin molded part 11. The inner peripheral surface of the hole has high dimensional accuracy suitable for the outer peripheral surface of the master shaft 1, and the separated master shaft 1 can be repeatedly used as an electroforming master.

  In addition, since the electroformed part 3 has a rough outer peripheral surface and a smooth inner peripheral surface due to the basic properties of electroforming, the inner peripheral surface of the shaft hole of the resin molded part 11 with respect to the outer peripheral surface of the electroformed part 3 is formed. The adhesive force is good, and the slidability with respect to the shaft used by being mounted on the inner peripheral surface of the electroformed part 3 of the bearing component 13 is also good, and there is no need to perform post-treatment such as polishing.

  In the case of the above embodiment, since the electroformed part 3 is integrated with the master shaft 1 and injection molding is performed, the electroformed part 3 can be easily inserted with good positioning accuracy, and from the electroformed part 3 after injection molding. The separated master shaft 1 can be used repeatedly as an electroforming master and is economical, and since a large number of bearing parts 13 are manufactured from the same electroforming master, a homogeneous product free from variations in dimensional accuracy can be obtained. .

  For example, when a conventional bearing part having a shaft hole electroformed is manufactured by a conventional technique, the shaft hole of a resin molded part that has been injection molded is subjected to electroforming later. In the present invention, it is extremely difficult to place electrodes in the holes, mask non-electroformed parts, and perform uniform and constant electroforming in the shaft holes. By using the means explained in the above, practical use was made possible.

The front view of the master axis | shaft (a) and electroformed axis | shaft (b) which are used for the manufacturing method of the resin-made bearing components to which this invention is applied. The typical principal part longitudinal cross-sectional view of the injection molding performed by inserting the electroformed shaft of FIG. FIG. 3 is a longitudinal sectional view of a resin molded product in which an electroformed shaft and a resin molded portion obtained by injection molding in FIG. The longitudinal cross-sectional view of the isolation | separation process which isolate | separates only a master axis | shaft from the resin molded product of FIG. 3, and obtains the bearing component with an electroformed part.

Explanation of symbols

1 Master shaft 2 Non-electroformed part (masking)
3 Electroformed part 4 Electroformed shaft 5 Upper mold 6 Lower mold 7 Spool 8 Runner 9 Gate 10 Cavity 11 Resin molded part 12 Resin molded product 13 Bearing parts

Claims (3)

The cylindrical electroformed part is integrally formed with the resin molded part by insert molding,
The electroformed part is separated from a master shaft that fits a shaft hole of a bearing part after insert molding, and has an inner peripheral surface of a shaft hole that conforms to the outer peripheral surface of the master shaft. Resin bearing parts characterized by A tubular electroformed part performs the steps of creating a electroformed shaft provided on the outer periphery of the matching master axis shaft hole of the bearing parts, the injection molding and mounting the electroformed shaft in a mold, the electroformed A step of producing a resin molded product with a shaft inserted, and a step of separating a master shaft from the resin molded product and forming a cylindrical electroformed portion, which is an electroformed shell, integrally formed in the shaft hole. A method for producing a resin bearing part, characterized in that:   The manufacturing method of the resin-made bearing parts of Claim 2 which repeatedly uses the master axis | shaft isolate | separated from the resin molded product as a master axis | shaft at the time of making an electroformed axis | shaft.

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