JP2007056923A - Manufacturing method of material for resin gear and manufacturing method of resin gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin gear for reducing generation of tooth-hitting sound by backlash and maintaining a damper function for a long period of time and a raw material for the resin gear. <P>SOLUTION: The material of the resin gear in which a metal bushing 1 is used as an insert and a ring-shape resin part 2 to be formed as a tooth part is integrally molded around the metal bushing 1 is manufactured as follows: The metal bushing 1 is equipped with a whirl-stop 4 protruding in a radial direction on an outer circumference face and the whirl-stop is covered by a rubber elastic layer 3. Using the metal bushing 1 as the insert, the ring-shape resin part 2 is integrally molded with the metal bushing 1 and embedded in the resin part 2 so as not to expose the whirl-stop 4 covered by the rubber elastic layer 3. The resin gear is manufactured by cutting a tooth profile from the resin part of the material of the resin gear manufactured with the above method. Preferably, mold-release characteristic is provided for an interface where the metal bushing 1 is directly integrated with the resin part 2 without intervened by the rubber layer 3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a resin gear material in which a metal bush is used as an insert, and a ring-shaped resin portion serving as a tooth portion is integrally formed around the metal bush. The present invention also relates to a method for manufacturing a resin gear using the manufactured resin gear material.

  In order to reduce the occurrence of rattling noise due to backlash, Patent Document 1 discloses a gear in which a metal core (metal bush) is inserted and engaged with an annular tooth having teeth on the outer periphery. This gear has a structure in which a gap is provided between the annular tooth body and the core body, and the gap is filled with an elastic body so that the annular tooth body and the core body can rotate relative to each other. The annular tooth body and the core body are engaged through the elastic body. However, if the deformation of the elastic body exceeds a predetermined amount, the annular tooth body and the core body are directly combined, and that of the elastic body. The above deformation is suppressed, thereby enhancing the durability of the elastic body. The elastic body is exposed at the open end of the surface perpendicular to the rotation axis direction of the gear, and the deformed elastic body escapes to the open end.

JP 2004-34874 A

However, when the deformation of the elastic body exceeds a predetermined amount, the annular tooth body and the core body are directly combined with each other, and in this state, the damper function does not work. Further, since the elastic body escapes to the open end when deformed, the large deformation is repeated, and the deterioration of the elastic body is accelerated by the creep phenomenon, and it is difficult to maintain the damper function for a long time.
The present invention has been made in view of the above problems, and provides a resin gear that reduces the occurrence of rattling noise due to backlash and maintains the damper function over a long period of time, and a material for the resin gear. is there.

  In order to solve the above-described problems, in the present invention, the production of a resin gear material in which a metal bush is used as an insert and a ring-shaped resin portion that becomes a tooth portion around the metal bush is integrally formed is as follows. Do as follows. That is, as the metal bush, a metal bush having a structure in which the outer peripheral surface has a detent protruding in the radial direction and the detent is covered with a rubber elastic layer is used. Then, using this metal bush as an insert, a ring-shaped resin portion is formed integrally with the metal bush, and is embedded in the resin portion so as not to expose the rotation stopper covered with the rubber elastic layer ( Claim 1). The resin gear is manufactured by cutting a tooth profile on the resin portion of the manufactured resin gear material (claim 3).

  According to the above, the detent covered with the rubber elastic layer is embedded in the resin portion so as not to be exposed, and the detent is always engaged with the resin portion via the rubber elastic layer. Accordingly, the rubber elastic layer can naturally be prevented from being greatly deformed inside the resin portion.

  In the invention according to claim 1, it is preferable that a release property is imparted to an interface where the metal bush is directly integrated with the resin portion without using the rubber elastic layer (invention 2). By doing so, the metal bush and the resin portion are engaged only at a location through the rubber elastic layer.

  As described above, according to the present invention, since the rotation stopper is always engaged with the resin portion via the rubber elastic layer, the collision energy applied to the gear is absorbed by the rubber elastic layer and always exhibits a damper function. Is done. The rotation stopper covered with the rubber elastic layer is embedded in the resin part so as not to be exposed, and the deformation of the rubber elastic layer when absorbing the collision energy applied to the gear is internally confined in the resin part. Because it happens, it can be prevented from deforming greatly. It is possible to provide a resin gear that can suppress deterioration due to the creep phenomenon of the rubber elastic layer and maintain the damper function over a long period of time.

  If releasability is given to the interface where the metal bush is directly integrated with the resin part without going through the rubber elastic layer, the metal bush is directly bonded and integrated with the resin part at this part. Therefore, all the collision energy applied to the gear is absorbed by the rubber elastic layer. Thereby, the effect as a damper function is further improved.

  In carrying out the method according to the present invention, a metal bush 1 shown in FIG. 1 is used. As shown in FIG. 1 (a) transverse sectional view and (b) longitudinal sectional view, the metal bush 1 is provided with convex detents 4 projecting radially in the outer peripheral surface at predetermined intervals. . The detent 4 is thinner than the metal bush 1 and is arranged at the center of the outer peripheral surface of the metal bush 1. A rubber elastic layer 3 is provided on the detent 4 of the metal bush 1 by a method such as injection molding or compression molding. In this embodiment, a rubber elastic layer having the same width as the thickness of the rotation stopper 4 is also provided on the outer circumferential surface between the rotation stoppers 4 arranged on the outer circumferential surface of the metal bush 1. As a material of the rubber elastic layer 3, for example, hydrogenated acrylonitrile butadiene rubber (HNBR), fluorine rubber or the like is used. The thickness of the rubber elastic layer 3 is set to about 0.5 to 1 mm. FIG. 2 is an enlarged view of the detent 4 portion (B portion in FIG. 1B) covering the rubber elastic layer 3.

Using the metal bush 1 as an insert, a ring-shaped resin portion 2 serving as a tooth portion is integrally formed with the metal bush 1 to form a resin gear material. At this time, the rotation stopper 4 covered with the rubber elastic layer 3 is embedded in the resin portion so as not to be exposed. The molding means may be any means such as injection molding, compression molding and injection molding.
In the injection molding, a ring-shaped reinforcing fiber base material is stacked in two stages in a molding die and arranged around a metal bush. At this time, the reinforcing fiber base material is arranged so that the rotation stopper is sandwiched from above and below by the two-layered ring-shaped reinforcing fiber base material. Then, the molding die is closed, and a liquid resin is injected to infiltrate the reinforcing fiber base, and the resin is cured by heating.
Also in the compression molding, the ring-shaped reinforcing fiber base and the metal bush are arranged in the molding die in the same manner as the injection molding. In this case, the ring-shaped reinforcing fiber base material is impregnated with a thermosetting resin in advance to be in a semi-cured state. Molding is performed by closing the molding die and curing the resin by heating and pressing.
In injection molding, a metal bush is placed in a molding die, and molding is performed by injecting a resin by a conventional method. A filler can be appropriately blended in the resin.

  A tooth shape is formed by cutting in the resin part 2 of the resin gear material manufactured as described above to manufacture a resin gear. Even if the centers of the metal bush 1 and the resin portion 2 do not coincide due to the uneven thickness of the rubber elastic layer 3, as described above, the tooth profile is obtained by cutting the resin portion 2 at the last stage. In this case, the resin part 2 can be cut so that the center of the resin bushing 2 matches the center of the metal bush 1 and the centers of both can be made to match.

  In the production of the resin gear material described above, it is preferable to provide releasability to the interface where the metal bush 1 is directly integrated with the resin portion 2 without the rubber elastic layer 3 interposed therebetween. Specifically, a release agent is applied in advance to the portion of the metal bush 1. The release agent application part of the metal bush 1 and the resin part 2 integrated with the part are in close contact but are not joined or adhered.

BRIEF DESCRIPTION OF THE DRAWINGS It is a resin gear which concerns on embodiment of this invention, Comprising: (a) is a cross-sectional view, (b) shows the longitudinal cross-sectional view. It is the figure which expanded and showed the B section of FIG.1 (b).

Explanation of symbols

1 is a metal bush 2 is a resin part 3 is a rubber elastic layer 4 is not rotating

Claims (3)

In the production of a resin gear material that uses a metal bush as an insert and integrally molds a ring-shaped resin part that becomes a tooth part around the metal bush,
As the metal bush, a metal bush having a structure that has a detent protruding in the radial direction on the outer peripheral surface thereof and the detent is covered with a rubber elastic layer,
A ring-shaped resin portion is formed integrally with the metal bush by using this metal bush as an insert, and is embedded in the resin portion so as not to expose the rotation stopper covered with the rubber elastic layer. Of manufacturing materials.   2. The method for producing a resin gear material according to claim 1, wherein a release property is imparted to an interface in which the metal bush is directly integrated with the resin portion without using a rubber elastic layer.   A method for manufacturing a resin gear, comprising: cutting a tooth profile into a resin portion of the resin gear material manufactured according to claim 1 or 2.

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