JP2002266984A - Resin gear and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin gear with improved high bonding strength of a ring-shaped molding body to a metallic bush, in the resin gear of which the gear part is formed out of a ring-shaped molding part using a ring-shaped reinforcing fiber base material with an inconspicuous seam. SOLUTION: The ring-shaped reinforcing base material 2 is used which is constituted by overlap-winding a band-shaped base material 1 knitted with flexibility to form a cylindrical shape and axially folding the cylindrical body in the form of a bellows shape. The gear part of the gear is formed out of the ring-shaped molded part where the ring-shaped reinforcing base material 2 is impregnated with resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin gear suitable for automobile parts and the like, and a method for manufacturing the same.

[0002]

2. Description of the Related Art The above-mentioned resin gear is used as a mating gear that meshes with a metal gear in order to suppress the generation of noise when the teeth mesh with each other, and is required to have excellent wear resistance and high strength. As a resin gear, a gear formed by processing a tooth on a ring-shaped molded product of a reinforcing fiber base material impregnated with a resin has been proposed.
For example, the following technology is disclosed (Japanese Patent Application No. 11-3084).
26). First, a belt-like felt is prepared. Here, the felt refers to a sheet body having a configuration in which reinforcing fibers accumulated in a planar direction are joined by reinforcing fibers oriented in a thickness direction. The belt-shaped felt is wound up in a tubular shape, and the tubular body is folded in a bellows shape in the axial direction to obtain a ring-shaped reinforcing fiber base material. Next, the ring-shaped reinforcing fiber base material is impregnated with a resin, and a metal bush is arranged at the center of the ring-shaped reinforcing fiber base material. After forming the shaped body, the teeth are processed around the ring shaped body.

[0003] In the ring-shaped reinforcing fiber base material, the joint between the base materials is not conspicuous in the circumferential direction. Moreover, the ring-shaped reinforcing fiber base material has a large number of reinforcing fibers not only in the circumferential direction but also in the radial direction. Be included. The reinforcing fiber oriented in the radial direction is expected to effectively receive the stress applied to the tooth surface of the driven gear.

[0004]

However, the ring-shaped reinforcing fiber base material in the above-mentioned technology expands in the radial direction.
Difficult to shrink. The ring-shaped reinforcing fiber base material is compressed to some extent by closing the molding die, and the shape is corrected to conform to the inner surface of the molding die and the outer peripheral surface of the metal bush, but expands and contracts as described above. It is difficult to correct the shape because of the difficulty. If molding is performed with a gap between the inner surface of the molding die or the outer peripheral surface of the metal bush and the ring-shaped reinforcing fiber base, the gap becomes a resin-rich layer with few reinforcing fibers, There is a concern that there may be places where bonding strength between the molded body and the metal bush is insufficient.

[0005] The problem to be solved by the present invention is to provide a resin gear in which a ring-shaped reinforcing fiber base is used as described above and the teeth of which are formed by the ring-shaped formed body. Is to make the reinforcing fiber density as uniform as possible, and to further strengthen the bonding strength between the ring-shaped molded body and the metal bush.

[0006]

The resin gear according to the present invention has a tooth portion formed of a ring-shaped molded product of a reinforcing fiber base material impregnated with a resin. In order to solve the above problems, the resin gear according to the present invention, the reinforcing fiber substrate,
It is a ring-shaped reinforcing fiber substrate in which a band-shaped base material woven with elasticity is wrapped and wound into a cylindrical shape, and the cylindrical body is folded in a bellows shape in the axial direction.

[0007] Such a reinforcing fiber base is ring-shaped, and the joint of the base is not conspicuous in the circumferential direction. In the folded configuration, the stitches of the band-shaped base material are radially aligned and have elasticity. Therefore, such a ring-shaped reinforcing fiber base material easily expands and contracts in the radial direction when it is compressed when the molding die is closed (the outer circumferential direction is a direction in which the diameter increases, and the inner circumferential direction is (In the direction in which the diameter is reduced), and it is possible to favorably conform to the inner surface of the molding die and the outer peripheral surface of the metal bush.

[0008] A tubular body woven or knitted with elasticity is rolled up from the end in the axial direction to form a ring-shaped reinforcing fiber base, and a resin gear is formed using such a reinforcing fiber base. There is a proposal to manufacture (JP-A-8-156124). In such a case, the diameter of the cylindrical body is changed according to the diameter of the resin gear to be manufactured. The work of weaving or knitting cylindrical bodies of various diameters depending on the gear to be manufactured is extremely complicated, and in some cases, it is not possible to prepare a cylindrical body of a required diameter. Further, in order to obtain a gear having a wide tooth width, it is necessary to stack ring-shaped reinforcing fiber base materials to secure the tooth width. On the other hand, in the present invention, it is possible to easily cope with a change in the diameter of the resin gear by changing the diameter of the winding core on which the belt-shaped substrate is overlapped and wound. Also, by increasing the amount of folding in a bellows, a wide tooth width can be ensured with one ring-shaped reinforcing fiber base material.

The above resin gear can be manufactured through the following steps (see FIG. 1). First, a belt-shaped base material 1 woven with elasticity is prepared. Next, the band-shaped base material 1 is overlapped and wound into a cylindrical shape, and the cylindrical body is folded in a bellows shape in the axial direction to form a ring-shaped reinforcing fiber base material 2.
By folding in a bellows shape, it is possible to obtain a state similar to that in which the base layers wound in layers are integrated. Before folding in a bellows shape, the layers of the band-shaped base material are not integrated, and because they are not integrated, slippage occurs between the base material layers when folded in a bellows shape, and the base material stretches, It can be folded neatly in a bellows shape, and after folding, it can create a state similar to that in which the base layers wound in layers are integrated. The ring-shaped reinforcing fiber base material 2 is impregnated with a resin, and heated and pressed or heated and molded in a molding die to form a ring-shaped molded body, and then teeth are processed around the ring-shaped molded body. When the ring-shaped reinforcing fiber base material 2 is compressed when the molding die is closed, the ring-shaped reinforcing fiber base material easily expands and contracts in the radial direction (the diameter increases in the outer circumference, and decreases in the inner circumference). Direction), along the inner surface of the molding die and the outer peripheral surface of the metal bush 3 well. Therefore, a resin-rich layer containing few reinforcing fibers cannot be formed in the molded product, and the density of the reinforcing fibers in the molded product can be made uniform.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The reinforcing fibers constituting the belt-like base material are as follows:
Natural fibers such as cotton and hemp, and organic fibers such as polyester, fluororesin, wholly aromatic polyester, poly-P-phenylene benzobisoxazole, para-aromatic polyamide, and meta-aromatic polyamide can be appropriately used. These fibers may be used alone or in combination of a plurality of types in consideration of the characteristics of a desired gear. A band-shaped substrate is formed by knitting a yarn obtained by converging or blending these fibers. By using a blended yarn of para-aromatic polyamide fiber and meta-aromatic polyamide fiber, it is possible to maintain a balance between workability and gear strength at the time of forming teeth around the ring-shaped molded product at a satisfactory level. it can.

The belt-shaped substrate 1 can naturally have elasticity by knitting yarn. It may be a flat cloth-like band base material that is flat-knitted, or a circular knitted tubular body may be cut open in the axial direction to form a band base material. The circularly knitted cylindrical body may be flattened to form a two-layered band-shaped base material.

The strip-shaped substrate 1 is wound around a core having a predetermined diameter to form a tube, and the tube is folded in a bellows shape in the axial direction to form a ring-shaped reinforcing fiber substrate 2. The lap winding and folding are performed, for example, as follows. The core is placed on the end of the band-shaped substrate, and the core is rotated to wind the band-shaped substrate. The wound band-shaped substrate 1 is placed in the preforming mold 4, and the band-shaped substrate portion is pressurized from at least one of its upper end and lower end to be folded in a bellows shape. At this time, by applying the predetermined heat, the folding effect is given by the iron effect,
It is preferable that the shape folded in a bellows shape is not bulky.

The molding of the ring-shaped molded body is performed by impregnating the above-mentioned ring-shaped reinforcing fiber base material 2 with an appropriate resin. For example, a ring-shaped reinforcing fiber base material is impregnated and dried with a phenol resin in advance, and then put into a molding die, and a metal bush 3 is arranged at the center to perform heat-press molding. In another method, a ring-shaped reinforcing fiber base is put into a molding die, a metal bush 3 is arranged at the center, the molding die is closed, and a liquid resin (crosslinked polyaminoamide, epoxy resin, polyimide, etc.) is poured. Inject and heat mold. The teeth are formed around the ring-shaped molded body obtained in this manner by cutting.
One gear may be formed with one ring-shaped reinforcing fiber base, or a plurality of ring-shaped reinforcing fiber bases may be integrally formed to cope with the manufacture of a gear having a large tooth width. You can also. However, since it is better not to form an interface of stacking, it is desirable to wind a wide band-shaped base material into a tubular shape, fold it in a bellows shape, and increase the thickness of one ring-shaped reinforcing fiber base material. 1 shows a case where one gear is formed using one ring-shaped reinforcing fiber base material 2, and the right-hand drawing shows the case where the ring-shaped reinforcing fiber base material 2 is formed. The case where two gears are used to form one gear is shown. Further, a plurality of ring-shaped reinforcing fiber base materials are stacked to form a long columnar body formed integrally, and teeth are formed by cutting around the ring-shaped formed body obtained by cutting this into a predetermined width. You can also. In this case, as the metal bush, a long rod-shaped body corresponding to the long pillar to be formed is used, or metal bushes having a thickness corresponding to the gears are stacked so as to be separable.

[0014]

EXAMPLES Example 1 Para-aramid fiber (fiber length 50 mm, fiber diameter 16 μm)
And meta-aramid fiber (fiber length 50mm, fiber diameter 16μ)
m) was blended at a mass ratio of 50/50 to prepare an aramid fiber yarn having a thickness of 20th. The flat knitted material which is weft knitted with one aramid fiber yarn is cut into a width of 220 mm to form a band-shaped substrate 1, and the band-shaped substrate 1 is wound around a predetermined axis four times,
A cylindrical body having an outer diameter of 80 mm, an inner diameter of 60 mm, and a height of 220 mm is further compressed in the axial direction in the preforming mold 11.
Ring-shaped reinforcing fiber base material 2 folded in a bellows shape in the axial direction
To form This ring-shaped reinforcing substrate 2 has an outer diameter of 90 m.
m, inner diameter 60 mm, thickness 40 mm. The above-mentioned ring-shaped reinforcing fiber base material 2 is put into a molding die, a metal bush 3 is arranged at the center, the molding die is closed, and a liquid resin (crosslinked polyaminoamide) is injected. The reinforcing fiber base 2 and the metal bush 3 were integrally formed by heating. The impregnation of the resin into the ring-shaped reinforcing fiber substrate is performed under reduced pressure (1300P
The cross-linking polyaminoamide was injected into the molding die at 200 ° C. described in a). The dimensions of the formed ring-shaped molded body were 90 mm in outer diameter, 60 mm in inner diameter, and 14 mm in thickness, and the resin content was 50% by mass. This shape and size are substantially achieved by closing the molding die and compressing the ring-shaped reinforcing fiber base material in the thickness direction and simultaneously expanding it in the radial direction. The gear teeth were formed by mechanical cutting around a ring-shaped molded body formed of the ring-shaped reinforcing fiber base material 2 to obtain a resin gear. The characteristics are shown in Table 1.

Conventional Example 1 Para-aramid fiber raw cotton (fiber diameter 5 to 20 μm, fiber length 50 mm) and meta-type aramid fiber raw cotton (fiber diameter 5 to 20 μm)
m, a fiber length of 50 mm) in the air at a weight ratio of 50/50 to be accumulated in the air.
A felt having a thickness of 000 mm, a thickness of 3 mm, and a unit weight of 150 g / m ² was prepared. This felt was cut into a width of 200 mm and wound around a predetermined shaft four times, and the outer diameter was 90 mm, the inner diameter was 60 mm,
A cylindrical body having a height of 200 mm is formed, and the cylindrical body is compressed in the axial direction in the same manner as in Example 1 and folded into a bellows shape to form a ring-shaped reinforcing fiber base material having an outer diameter of 90 mm, an inner diameter of 60 mm, and a thickness of 40 mm. . Hereinafter, a resin gear was formed in the same manner as in the example. The characteristics are shown in Table 1.

REFERENCE EXAMPLE 1 A cylindrical body obtained by circularly knitting aramid fiber yarn is wound up in the axial direction from the end to form a ring-shaped reinforcing fiber base material having an outer diameter of 90 mm, an inner diameter of 60 mm and a thickness of 20 mm. Two such ring-shaped reinforcing fiber base materials were used in layers, and a resin gear was formed in the same manner as in Example 1. The characteristics are shown in Table 1.

The characteristics shown in Table 1 were measured as follows. In addition, the content of the reinforcing fiber in the resin of the resin gears of each example is the same. The bending strength is obtained by measuring the bending strength (initial strength) of an arc-shaped sample cut out from three tooth portions of the manufactured resin gear. The mounting endurance time was measured in a gear acceleration test of an automobile engine (rotation speed: 6000 rpm, oil temperature 130 ° C., tooth root load stress 25).
The durability time at 5 MPa) was measured. The maximum and minimum values of the measured values of ten samples are shown. The detachment strength is a pressing force when the metal bush is pressed while supporting the teeth of the resin gear and the joint between the ring-shaped molding and the metal bush is broken. The results measured for three resin gears are shown. The tooth breaking strength is a press-fit when a steel ball is press-fitted between teeth of a resin gear and the tooth breaks. The result measured about three tooth parts is shown.

[0018]

[Table 1]

In Reference Example 1, two ring-shaped reinforcing fiber substrates are continuously stacked in order to set the tooth width to a predetermined size. In the embodiment according to the present invention, it is possible to secure a predetermined tooth width by using one ring-shaped reinforcing fiber base material, and the tooth part breaking strength is increased.

[0020]

As described above, the resin gear according to the present invention has the easiness of changing the diameter and thickness dimensions of the gear to be manufactured while securing the coupling strength between the ring-shaped molded body and the metal bush. ing.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a step of producing a ring-shaped reinforcing fiber base from a band-shaped base in an example according to the present invention.

[Explanation of symbols]

 1 is a band-shaped base material 2 is a ring-shaped reinforcing fiber base material 3 is a metal bush 4 is a preforming die

Continued on the front page F term (reference) 3J030 AC03 BC01 BC10 4F204 AA37 AA39 AA40 AD16 AG13 AG28 AH12 FA01 FB01 FB11 FF05 FN11 4F213 AA36 AD16 AG28 AH12 WA16 WA53 WA57 WA83 WB01 WB11

Claims (2)

[Claims] 1. A resin gear in which a tooth portion is formed by a ring-shaped molded body of a reinforcing fiber base material impregnated with a resin, wherein the reinforcing fiber base material is formed by winding a band-shaped base material woven with elasticity. A resin gear comprising: a ring-shaped reinforcing fiber base obtained by forming a cylindrical body and folding the cylindrical body in a bellows shape in an axial direction. 2. A method of manufacturing a resin gear, comprising the following steps (1) to (4). (1) a step of preparing a band-shaped base material woven with elasticity; and (2) a ring shape obtained by laminating and winding the band-shaped base material into a tubular shape, and further folding the tubular body in a bellows shape in the axial direction. (3) a step of impregnating the ring-shaped reinforcing fiber base material with a resin, and heating and pressure molding or heat molding in a molding die to form a ring-shaped molded article; 4) processing teeth around the ring-shaped molded body;