JPH0788866A - Production of gear made of phenol resin - Google Patents

Abstract

PURPOSE:To produce a gear made of a phenol resin having no directional property of strength in the tooth part thereof, reduced in strength difference with place and holding high strength by using a molding material obtained by a specific manufacturing method. CONSTITUTION:A phenol resin powder and chopped aramide fibers are dispersed in water to be formed into a sheet like molding material 1 by a papermaking process and this molding material 1 is punched into a parallelogrammic shape with a width of 140mm, a length of 460mm and one mutually opposed angles of 60 deg.. Two mutually opposed short sides of the molding material are abutted to form a cylindrical body 2. This cylindrical body 2 is charged in a temporary mold 13 and axially compressed to be temporarily molded to obtain a doughnut- shaped molding material for constituting a tooth part. A metal bush is arranged to the central part of a final mold and the molding material 3 for constituting the tooth part is arranged to the periphery of the bush and subjected to compression molding at 190 deg.C to be integrated with the bush. After molding, teeth are formed to the part molded from the molding material by mechanism cutting.

Description

Detailed Description of the Invention

[0001]

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

[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 noise generation during tooth meshing, and is required to have excellent wear resistance and high strength. Conventionally, there are the following two methods for manufacturing resin gears. As shown in FIG. 5, the metal bush 5 is arranged at the center, the web forming molding material 8 is arranged in the periphery thereof, and the tooth portion forming molding material 3 is arranged at the outermost periphery thereof, and they are integrally heated and pressed in the die 9. A manufacturing method in which molding is performed, and after molding, the teeth are machined to form resin gears. Here, the molding material 3 for forming the tooth portion is as shown in FIG.
As shown in, a woven cloth substrate of cotton cloth or aramid fiber is wound in a rod shape with a prepreg 10 impregnated with a phenol resin varnish and dried to be in a semi-cured state (B stage), and further, this rod-shaped body 11 is formed into a donut shape. It is the one. Further, as shown in FIG. 7, the web-forming molding material 8 is obtained by putting a chip piece 12 obtained by cutting a prepreg into a temporary molding die 13 and temporarily molding it into a donut shape. Phenolic resin and aramid fibers and other reinforcing fibers are mixed and kneaded to prepare a granulated molding material, and the metal mold is placed in a mold to inject the molding material into the mold. A manufacturing method in which a resin gear is formed by machining.

[0003]

In the above manufacturing method,
The tooth-forming molding material 3 is a doughnut-shaped rod-shaped body 11, and the direction of the weave of the woven fabric is irregular at the joint portion where the rod-shaped body 11 is donut-shaped. as a result,
The strength of the tooth portion of the molded resin gear is reduced at the portion corresponding to the joint. Further, in the above manufacturing method, it is difficult to obtain sufficient strength as the entire resin gear. This is because when the reinforcing fiber is mixed and kneaded with the phenol resin to form a molding material, the reinforcing fiber is broken or cut to be short. Further, when injection molding is performed, the reinforcing fibers are cut by the screw of the cylinder of the molding machine or the gate of the mold, so that the strength is greatly reduced. Then, in the injection molding, the reinforcing fibers are oriented in the resin flow direction so that the strength becomes directional, and the strength at the weld occurrence portion becomes lower than the strength at other portions.

[0004] The problem to be solved by the present invention is to increase the strength of the tooth portion of the molded resin gear and to prevent the difference in strength depending on the location. Further, by adopting the heat and pressure molding method, it is possible to prevent the directionality of strength and the decrease in strength such as a welded portion as in the case of adopting the injection molding method.

[0005]

In order to solve the above problems, the first method for producing a phenol resin gear according to the present invention uses a phenol resin powder and a reinforcing fiber as essential components and disperses them in a liquid. The sheet-shaped molding material thus formed is formed into a cylindrical shape, and the cylindrical body is pressed in its axial direction to obtain a molding material for forming a tooth portion. Then, a step of arranging the molding material for forming the tooth portion around the bush arranged at the center and heat-pressing and molding both of them is integrated. In the second production method according to the present invention, a phenolic resin powder and a reinforcing fiber as essential components are dispersed in a liquid to form a sheet-shaped molding material, which is formed into a tubular shape, and the tubular body is Axial pressure is applied to form a tooth part forming material. Separately, a doughnut-shaped molding material for forming a web is prepared by dispersing phenol resin powder and reinforcing fibers as essential components in a liquid and making them into paper. Then, the molding material for forming the web is arranged around the bush arranged at the center, the molding material for forming the tooth portion is arranged at the outermost periphery, and the steps of heating and pressing the three members to integrate them are performed. Characterize.

In the first and second manufacturing methods described above, the sheet-shaped molding material for forming the tubular body is a parallelogram or a rectangle, and it is preferable that the two opposing sides are abutted to form a cylindrical shape. At that time, the number of sheet-shaped molding materials is not limited to one, and a plurality of sheets may be connected and used. The sheet-shaped molding material for forming the tubular body may be cut into a predetermined size and shape after being made into paper, or may be cut into a predetermined size and shape suitable for forming the tubular body from the beginning. Then, the cutting step may be omitted.

[0007]

In the method according to the present invention, the molding material is prepared by forming the reinforcing fibers dispersed in the liquid into paper. Therefore, as in the case of the molding material in which the reinforcing fibers are prepared by the conventional mixing and kneading, The initial fiber length can be maintained almost as it is without breaking due to external force. Further, the reinforcing fibers are not mixed in a particular direction, and a molding material in which the reinforcing fibers and the phenol resin powder are uniformly dispersed is obtained. As a result, the resin gear obtained by heating and molding this molding material retains the expected strength and loses the directionality of the strength. When the sheet-shaped molding material is formed into a tubular shape, joints are formed, but since the molding material prepared by papermaking tends to flow the reinforcing fibers due to the flow of resin during molding, the reinforcing fibers in the joints are entangled with each other. , Approaching a seamless state. As a result, the difference in strength from the portion other than the joint portion is reduced. When a parallelogram is used as the sheet-shaped molding material formed in a tubular shape, the joints formed in the tubular body appear obliquely with respect to the axial direction of the tubular body. Therefore, it is preferable that the portion whose strength is likely to be lowered due to the presence of the joint does not appear as a straight line in the axial direction but is dispersed in the circumferential direction of the gear.

Although the resin portion of the gear may be composed only of the tooth part forming molding material, if the web forming molding material is separately prepared by papermaking as in the second manufacturing method, the gear characteristics are well balanced. The degree of freedom in selecting the reinforcing fiber for the purpose is increased. For example, when using aramid fibers as the reinforcing fibers of the tooth portion forming molding material, glass fibers other than the aramid fibers and glass fibers are blended in the reinforcing fibers of the web forming molding material in order to reduce the dimensional shrinkage of the gear. Further, it is possible to mix a filler powder having a small shrinkage.

[0009]

EXAMPLES In carrying out the production method according to the present invention, the particle size of the phenol resin powder is suitably 1 to 100 μm, but it is not particularly limited as long as it can be dispersed at the time of papermaking. The reinforcing fibers are chopped, and include para-type aramid fibers (poly-p-phenylene terephthalamide (PPTA)), meta-type aramid fibers (poly-m-phenylene isophthalamide (PMIA)), glass fibers,
Examples include cotton fiber and carbon fiber. At the time of papermaking, other fillers and additives may be appropriately mixed. Hereinafter, examples according to the present invention will be described in detail.

Example 1 Phenolic resin powder (particle diameter 1 to 20 μm) and para-aramid fiber chop (fiber diameter 5 to 20 μm, fiber length 3 mm)
And meta-aramid fiber chop (fiber diameter 5-20μ
m, fiber length 3 mm) is dispersed in water at a weight ratio of 60/20/20, and this is paper-made to obtain a sheet-shaped molding material 1. As shown in Figure 1, this is 140 mm wide and 46 mm long.
It was punched into a parallelogram at 0 mm with one opposite angle of 60 °. Two shorter sides of this molding material that face each other are butted to form a tubular body 2. Then, it is put into a temporary molding die 13, compressed in the axial direction of the tubular body 2 and temporarily molded to obtain a doughnut-shaped molding material 3 for forming a tooth portion. In the molding material 3 for forming a tooth portion, the joint 4 appears at one position obliquely with respect to the axial direction. As shown in FIG. 2, the metal bush 5 is arranged in the center of the main molding die 9, and the molding material 3 for forming the tooth portion is arranged around the metal bush 5, and heat press molding is performed at 190 ° C. Integrated. After molding, the teeth are formed by machine cutting on the parts molded with the molding material 3 for forming the tooth part to obtain resin gears. The characteristics are shown in Table 1.

Example 2 Phenolic resin powder (particle size 1 to 20 μm) and para-aramid fiber chop (fiber diameter 5 to 20 μm, fiber length 3 mm)
And meta-aramid fiber chop (fiber diameter 5-20μ
m, fiber length 3 mm) is dispersed in water at a weight ratio of 60/20/20, and this is paper-made to obtain a sheet-shaped molding material 1. As shown in Fig. 3, this is 140 mm wide and 23 mm long.
Two parallelograms were punched out at 0 mm, one of the opposite angles being 60 °. The shorter sides of the two molding materials are joined together to form a tubular body 2. Then, it is put into a temporary molding die 13, compressed in the axial direction of the tubular body 2 and temporarily molded to obtain a doughnut-shaped molding material 3 for forming a tooth portion. In the tooth part forming molding material 3, the joints 4 appear at two positions obliquely with respect to the axial direction. Hereinafter, a resin gear was prepared in the same manner as in Example 1. The characteristics are shown in Table 1.

Example 3 Phenolic resin powder (particle size 1 to 20 μm) and para-aramid fiber chop (fiber diameter 5 to 20 μm, fiber length 3 mm)
And meta-aramid fiber chop (fiber diameter 5-20μ
m, fiber length 3 mm) is dispersed in water at a weight ratio of 60/20/20, and this is made into a sheet to obtain a sheet-shaped molding material. This was punched into a rectangle having a width of 140 mm and a length of 460 mm. The two shorter sides of this molding material are butted to form a tubular body. Then, it was put into a temporary molding die, compressed in the axial direction of the cylindrical body and temporarily molded to obtain a donut-shaped molding material for forming a tooth portion. The obtained molding material for forming a tooth part has a joint formed by abutting two opposite sides of a rectangle,
It appears at one location in the axial direction. Hereinafter, a resin gear was prepared in the same manner as in Example 1. The characteristics are shown in Table 1.

Example 4 Phenolic resin powder (particle size 1 to 20 μm) and para-aramid fiber chop (fiber diameter 5 to 20 μm, fiber length 3 mm)
And meta-aramid fiber chop (fiber diameter 5-20μ
m, fiber length 3 mm) is dispersed in water at a weight ratio of 60/20/20, and this is made into a sheet to obtain a sheet-shaped molding material. This was punched into two rectangular pieces having a width of 140 mm and a length of 230 mm. The shorter sides of the two molding materials are joined together to form a tubular body. Then, it was put into a temporary molding die, compressed in the axial direction of the cylindrical body and temporarily molded to obtain a donut-shaped molding material for forming a tooth portion. In the obtained molding material for forming a tooth portion, joints formed by abutting rectangular sides with each other appear at two positions in the axial direction. Hereinafter, a resin gear was prepared in the same manner as in Example 1. The characteristics are shown in Table 1.

Example 5 Phenolic resin powder (particle size 1 to 20 μm) and para-aramid fiber chop (fiber diameter 5 to 20 μm, fiber length 3 mm)
And meta-aramid fiber chop (fiber diameter 5-20μ
m, fiber length 3 mm) is dispersed in water at a weight ratio of 60/20/20, and this is paper-made to obtain a sheet-shaped molding material 1. As shown in Figure 1, this is 140 mm wide and 46 mm long.
It was punched into a parallelogram at 0 mm with one opposite angle of 60 °. Two shorter sides of this molding material that face each other are butted to form a tubular body 2. Then, it is put into a temporary molding die 13, compressed in the axial direction of the tubular body 2 and temporarily molded to obtain a doughnut-shaped molding material 3 for forming a tooth portion. In the molding material 3 for forming a tooth portion, the joint 4 appears at one position obliquely with respect to the axial direction. Separately, phenol resin powder (particle size 1-2
0 μm) and glass fiber chop (fiber diameter 10 to 30 μm)
m, fiber length 3 mm and 6 mm) and cotton fiber chop (fiber diameter 5 to 20 μm, fiber length 3 mm and 6 mm) in a weight ratio of 50
It was dispersed in water at a ratio of / 25/25, and this was made into paper to obtain a sheet-shaped molding material 6. As shown in FIG.
It was punched into a donut shape of 115 × φ55 mm to obtain a molding material 8 for forming a web. Next, as shown in FIG. 5, the metal bush 5 is arranged in the central portion of the main molding die 9, the above-described molding material 8 for forming a web is formed around the bush 5, and the molding material 3 for forming a tooth portion is formed on the outermost periphery. After arranging them, they were heated and pressed at 190 ° C. to integrate the three members. Hereinafter, a resin gear was prepared in the same manner as in Example 1. The characteristics are shown in Table 1.

In the above-mentioned examples, the sheet-shaped molding material produced by papermaking was cut into a predetermined size and shape to form a material for forming a tubular body. The remaining cut material is easily loosened by immersing it in water, so that it can be redispersed and used for the sheet-forming molding process. However, the cutting step can be omitted if the paper is made into a predetermined size and shape from the beginning. This also applies to the case where a donut-shaped molding material for forming a web is manufactured by papermaking. Further, in the above embodiment, the shape of the sheet-shaped molding material forming the tubular body is a parallelogram or a rectangle, but the shape is not particularly limited as long as it can be formed into a tubular shape, and when formed into a tubular shape. The joints may be intermeshed so that they mesh with each other.

Conventional Example 1 Meta-type / para-type composite aramid fiber woven fabric (fiber thickness: 2 denier, thread thickness: cotton thread standard number 20 thread, number of threads per inch: 55, width: 55) Then, it is impregnated with a phenol resin and dried to obtain a prepreg 10. As shown in FIG. 6, the prepreg 10 was heated on a hot platen to be softened and wound into a rod shape, and the rod-shaped body 11 was further formed into a donut shape to obtain a tooth portion forming molding material 3. Separately, as shown in FIG. 7, each of the phenol resin-impregnated aramid woven cloth prepreg and the phenol resin-impregnated cotton cloth prepreg is cut into 5 mm squares to obtain chip pieces 12, and the phenol resin-impregnated glass woven cloth prepreg is cut into 10 mm squares. To obtain a chip piece 12. These chip pieces 12 were mixed and put into a temporary molding die 13 and temporarily molded at 100 ° C. to obtain a doughnut-shaped molding material 8 for forming a web. Hereinafter, as in the case of Example 5, the metal bush 5 is arranged in the center of the main molding die 9, the above-described molding material 8 for forming a web is arranged around the bush 5, and the molding material 3 for forming a tooth portion is arranged at the outermost periphery. Then, heat and pressure molding was performed at 180 ° C. to integrate the three members. Hereinafter, a resin gear was prepared in the same manner as in Example 1. The characteristics are shown in Table 1.

Conventional Example 2 Phenolic resin and para-aramid fiber (fiber diameter 5 to 20)
μm, fiber length 3 mm) and meta-aramid fiber (fiber diameter 5)
〜20μm, fiber length 3mm), weight ratio 50/25/2
The mixture was mixed and kneaded at a ratio of 5 to obtain a granular molding material. The molding material was injected and molded into a mold having a metal bush arranged at the center, and after molding, tooth portions were formed by machining to obtain a resin gear. The characteristics are shown in Table 1.

In Table 1, each characteristic is measured as follows. The column A of the bending strength is a resin gear cut out from a portion corresponding to a butt portion of the sheet-shaped molding material (joint portion in which the rod-shaped body is a donut shape in Conventional Example 1 and a weld generation portion in Conventional Example 2). 3 shows the bending strength of the tooth portion of. The column B shows the bending strength of the tooth portion of the resin gear cut out from the portion other than the above. The mounting durability time was measured by a cam gear acceleration test of an automobile engine (rotational speed: 3000 rpm, oil temperature 130 ° C., tooth root load stress 18 kg / mm ² ). The dimensional change rate is 200 ° C when the resin gear is put in the hot air circulation dryer.
The sample was subjected to a heat treatment of × 500 hours, and the dimensional change rate of the tooth outer diameter before and after the treatment was measured.

[0019]

[Table 1]

[0020]

As described above, in the method for manufacturing a phenol resin gear according to the present invention, the reinforcing fibers in the resin of the molded gear retain the initial fiber length without being too short. Further, there is no directivity in which the reinforcing fibers are oriented in a specific direction. Furthermore, the joints when the sheet-shaped molding material is formed into a tubular shape are close to the state of disappearance after the gear is molded. As a result, it is possible to obtain a resin gear having a large strength and a small strength difference depending on the direction of the strength and the location.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of a step of preparing a tooth part forming molding material in a manufacturing method according to the present invention.

FIG. 2 is a cross-sectional explanatory view showing an example of a step of heat-press molding a resin gear in the manufacturing method according to the present invention.

FIG. 3 is an explanatory view showing another embodiment of the step of preparing a tooth part forming molding material in the manufacturing method according to the present invention.

FIG. 4 is an explanatory view showing an example of a step of preparing a web-forming molding material in the manufacturing method according to the present invention.

FIG. 5 is a cross-sectional explanatory view showing another embodiment of the step of heat-press molding a resin gear in the manufacturing method according to the present invention.

FIG. 6 is an explanatory view showing a step of preparing a tooth part forming molding material by a conventional method.

FIG. 7 is an explanatory diagram showing a step of preparing a web-forming molding material by a conventional method.

[Explanation of symbols]

 1 is a sheet-shaped molding material 2 is a tubular body 3 is a tooth part forming molding material 4 is a joint 5 is a metal bush 6 is a sheet forming material 8 is a web forming molding material 9 is a main molding die 13 is a temporary molding Mold

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Claims (8)

[Claims] 1. A sheet-shaped molding material prepared by dispersing a phenol resin powder and a reinforcing fiber as essential components in a liquid to form a sheet, and pressing the tubular body in its axial direction to form a tooth portion. As a constituent molding material, the tooth constituent constituent molding material is arranged around a bush arranged at the center, and the two are subjected to heat pressure molding to integrate the two, and the phenol resin gear is characterized in that Manufacturing method. 2. A sheet-shaped molding material obtained by dispersing a phenol resin powder and a reinforcing fiber as essential components in a liquid and forming them into a tubular shape, and pressurizing the tubular body in its axial direction to form a tooth portion. A doughnut-shaped web forming molding material prepared by dispersing these into a liquid with phenol resin powder and reinforcing fiber separately as essential components as a forming molding material, and the web forming around the bush arranged at the center. A molding method for phenol resin gears, characterized in that the molding material for forming a tooth portion is arranged on the outermost periphery, and a step of heat-press molding and integrating the three is performed. 3. The method for producing a phenol resin gear according to claim 1, wherein the sheet-shaped molding material is a parallelogram, and two opposite sides thereof are butted to form a cylindrical shape. 4. The method for producing a phenol resin gear according to claim 1, wherein the sheet-shaped molding material is rectangular, and two opposite sides thereof are abutted to form a cylindrical shape. 5. The method for producing a phenol resin gear according to claim 1, wherein a plurality of parallelogram sheet-shaped molding materials are joined together to form a cylindrical shape. 6. The method for producing a phenol resin gear according to claim 1, wherein a plurality of rectangular sheet-shaped molding materials are joined together to form a cylindrical shape. 7. The phenolic resin product according to claim 2, wherein the sheet-shaped molding material for forming the tubular body is formed into a sheet and then cut into a predetermined size and shape. Gear manufacturing method. 8. A sheet-shaped molding material for forming a tubular body is formed into a predetermined size and shape suitable for forming the tubular body, and the sheet-shaped molding material is manufactured. The method for producing a gear made of phenolic resin according to 1.