Method for manufacturing molding material for resin gears

Abstract

To provide a method for manufacturing a molding material for a resin gear, a method for manufacturing a resin gear, and a molding material for a resin gear which can prevent the occurrence of impregnation defects of resin in a molded product.SOLUTION: A method for manufacturing a molding material 6 for resin gears includes the steps of: preparing a raw material 5 containing thermosetting resin powder 2 and wet fibers 3 having a water content of 10-25 wt.%; and mixing the raw material 5 with a mixer 10 for a predetermined time, thereby forming a plurality of granular molding materials 6 for resin gears.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for producing a molding material for a resin gear, a method for producing a resin gear, and a molding material for a resin gear. [Background technology]

[0002] Resin gears are lightweight and quiet, and are widely used, for example, as gears for vehicles or industrial applications. Known methods for manufacturing such resin gears use a resin gear molding material containing fibers and a thermosetting resin. For example, the manufacturing method described in Patent Document 1 includes the steps of dispersing phenolic resin powder, aramid fibers, and the like in water and forming the resulting material into a sheet, and cutting the resulting material into gear shapes and stacking multiple sheets of the material to form a preform that is compression-molded while being heated. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-51097 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, resin gear molding materials are produced by kneading fibers and a thermosetting resin using, for example, a roll mixer or kneader. However, in this case, the kneading process involves applying heat, which accelerates the resin curing reaction and increases the viscosity of the resin gear molding material. Therefore, when resin gears are produced using this resin gear molding material, the resin flow during molding is reduced, which can lead to poor resin impregnation of the molded product.

[0005] Therefore, an object of the present invention is to provide a method for manufacturing a molding material for a resin gear, a method for manufacturing a resin gear, and a molding material for a resin gear, which are capable of suppressing the occurrence of poor resin impregnation in a molded product. [Means for solving the problem]

[0006] A method for producing a resin gear molding material according to one embodiment of the present invention is a method for producing a resin gear molding material, and includes a first step of preparing raw materials containing a thermosetting resin powder and wet fibers having a moisture content of 10 to 25% by weight, or fibers and water that realize the wet fibers, and a second step of mixing the raw materials in a mixer for a predetermined period of time to form a plurality of granular resin gear molding materials.

[0007] In this method for producing a resin gear molding material, the raw materials are mixed in a mixer for a predetermined time, preventing the resin powder from melting due to heat. This method allows the resin powder to adhere to the wet fibers or fiber surfaces. Furthermore, by using wet fibers with a moisture content of 10 to 25%, or fibers and water that produce such wet fibers, the resin powder is prevented from falling off the wet fibers or fiber surfaces. This allows the raw materials to be reliably granulated into a plurality of granular resin gear molding materials without promoting the curing reaction of the resin powder. This method also prevents resin flow degradation during molding using the produced resin gear molding material, thereby preventing poor resin impregnation in molded products.

[0008] In the method for producing a resin gear molding material according to one aspect of the present invention, the mixer may include a container for storing the raw materials and a stirring blade disposed in the container for stirring the raw materials. By using such a mixer, it is possible to efficiently mix the raw materials while achieving the above-described effects.

[0009] In the method for producing a resin gear molding material according to one aspect of the present invention, the wet fibers or fibers may contain inorganic fibers, which makes it possible to easily obtain a resin gear molding material having a long fiber length.

[0010] In the method for producing a resin gear molding material according to one aspect of the present invention, the resin powder may contain a phenolic resin powder, thereby enabling the resin gear molding material to be produced using a phenolic resin as the thermosetting resin powder.

[0011] In the method for producing a resin gear molding material according to one aspect of the present invention, water may be added to the raw materials during mixing in the second step, thereby adjusting the moisture content of the raw materials in the second step and further preventing the resin powder from falling off the wet fibers or the surface of the fibers.

[0012] A method for manufacturing a resin gear according to one aspect of the present invention is a method for manufacturing a resin gear having an annular resin member using a resin gear molding material manufactured by the above-mentioned method for manufacturing a resin gear molding material, and includes the steps of filling a mold with the resin gear molding material and heating and compressing the resin gear molding material to form the resin member. In this method for manufacturing a resin gear, the molding material resin member manufactured by the above-mentioned method for manufacturing a resin gear molding material is used for molding, and therefore it is possible to prevent poor resin impregnation of the resin member.

[0013] A resin gear molding material according to one aspect of the present invention is a resin gear molding material produced by the above-described manufacturing method, which comprises a plurality of fibers, at least a portion of which is opened to form a ball-shaped fiber portion, and a thermosetting resin powder adhered to the surfaces of the plurality of fibers, and has a bulk density of 0.03 to 0.05 g / mL. By using this resin gear molding material to produce a resin gear, it is possible to prevent poor resin impregnation of the resin member. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a method for manufacturing a molding material for a resin gear, a method for manufacturing a resin gear, and a molding material for a resin gear, which are capable of suppressing the occurrence of poor resin impregnation in a molded product. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a front view showing a resin gear according to an embodiment. [Figure 2] Fig. 2(a) is a diagram for explaining a method for producing a resin gear molding material according to an embodiment. Fig. 2(b) is a diagram continuing from Fig. 2(a). Fig. 2(c) is a diagram continuing from Fig. 2(b). [Figure 3] FIG. 3 is a perspective view showing a mixer used in the method for producing a resin gear molding material according to the embodiment. [Figure 4] FIG. 4 is a schematic view showing a molding material for a resin gear according to an embodiment. [Figure 5] Figure 5(a) is a photograph showing the result of mixing the raw materials when the mixing time was 30 seconds, and Figure 5(b) is a photograph showing the result of mixing the raw materials when the mixing time was 60 seconds. [Figure 6] Figure 6(a) is a photograph showing the result of mixing raw materials when the mixing time was 2 minutes, Figure 6(b) is a photograph showing the result of mixing raw materials when the mixing time was 5 minutes, and Figure 6(c) is a photograph showing the result of mixing raw materials when the mixing time was 10 minutes. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding elements are designated by the same reference numerals, and redundant description will be omitted.

[0017] As shown in Fig. 1, the resin gear 1 manufactured by the manufacturing method according to this embodiment is a so-called high-strength resin gear, and is used as a gear for vehicles or industrial applications. For example, the resin gear 1 can be used as a balance shaft gear or camshaft gear in an engine. The resin gear 1 includes a metal bushing 8 and a resin member 9. The resin gear 1 is a spur gear.

[0018] The metal bushing 8 is a component that is attached to, for example, a rotating shaft (not shown). The metal bushing 8 is annular. The metal bushing 8 is made of a metal such as stainless steel. A through hole 8h is provided in the metal bushing 8. The rotating shaft is inserted into the through hole 8h. The resin member 9 is a component that meshes with another gear. The resin member 9 is annular. The resin member 9 is made of resin. The resin member 9 is provided around the metal bushing 8. Tooth profiles 9a are formed on the outer periphery of the resin member 9. A plurality of tooth profiles 9a are formed at predetermined intervals in the circumferential direction of the resin member 9.

[0019] Next, an example of a manufacturing method according to this embodiment will be described.

[0020] The manufacturing method according to this embodiment includes a manufacturing method for manufacturing a resin gear molding material 6, which is a molding material for a resin gear 1, and a manufacturing method for manufacturing a resin gear 1 using the resin gear molding material 6.

[0021] First, a resin gear molding material 6 is produced. As shown in Fig. 2(a), a raw material 5 containing (i) thermosetting resin powder 2, (ii) wet fiber 3 with a moisture content of 10 to 25% by weight, and (iii) additive (or filler) 4 is prepared (first step).

[0022] Examples of the resin powder 2 include phenol resin, imide resin, melamine resin, and epoxy resin. The resin powder 2 preferably has a particle diameter of about 1 to 200 μm. One type of resin or a combination of two or more types of resins can be used as the resin powder 2. The amount of resin powder 2 in the resin gear molding material 6 is preferably 30 to 80% by weight, and more preferably 45 to 65% by weight.

[0023] Examples of fibrous materials constituting the wet fibers 3 include meta-aramid fibers, para-aramid fibers, acrylic fibers, cellulose fibers, carbon fibers, phenolic resin fibers, and polyimide fibers. The wet fibers 3 may contain inorganic fibers, such as carbon fibers, alumina fibers, alumina-silica fibers, glass fibers, mineral fibers, and ceramic fibers. The fiber length of the fibrous material is preferably 1 to 6 mm. The wet fibers 3 may be one type of fibrous material or a combination of two or more types of fibrous materials. The amount of the wet fibers 3 in the resin gear molding material 6 is preferably 25 to 55% by weight, and more preferably 35 to 45% by weight.

[0024] Examples of additives 4 include montanic acid ester, zinc stearate, talc, silicone rubber, zirconia, alumina, silica, barium sulfate, calcium carbonate, mica, potassium titanate, graphite, antimony trioxide, and antimony disulfide. The amount of additives 4 in the resin gear molding material 6 is preferably 0 to 20% by weight, and more preferably 0.5 to 15% by weight.

[0025] As shown in Fig. 2(b), the raw materials 5 are mixed for a predetermined time in a mixer 10 to form a plurality of granular resin gear molding materials 6 as shown in Fig. 2(c) (second step). The mixer 10 and the mixing method therefor are not particularly limited as long as the raw materials can be mixed uniformly. For example, a Lödige mixer (manufactured by Lödige GmbH) or an Einrich mixer (manufactured by Nippon Eirich GmbH) can be used as the mixer 10.

[0026] In this embodiment, an Einrich mixer is used as the mixer 10. As shown in FIG. 3, the mixer 10 has a base 11, a mixing pan 12, a rotor 13, and a blade 14. The base 11 rotatably supports the mixing pan 12 and the rotor 13. The mixing pan 12 is a container that contains the raw materials 5. The rotor 13 is a stirring blade that stirs the raw materials 5. The rotor 13 is disposed within the mixing pan 12. In this mixer 10, the rotor 13 and the mixing pan 12 rotate at high speed, reducing the dead zone within the mixing pan 12. Furthermore, in this mixer 10, the blade 14 scrapes off materials that are concentrated on the side of the mixing pan 12 due to centrifugal force, and the tilted mixing pan 12 allows the scraped materials to come into contact with the rotor 13, resulting in efficient mixing.

[0027] As shown in FIG. 4, the resin gear molding material 6 includes a fiber portion 60 and a resin powder 62. The fiber portion 60 includes a plurality of fibers 61. The fibers 61 correspond to the wet fibers 3 described above. At least a portion of the fiber portion 60 is spread. The fiber portion 60 does not have a two-dimensional planar shape, but has a three-dimensional solid shape (lump). The resin powder 62 is a thermosetting resin corresponding to the resin powder 2 described above. The resin powder 62 is attached to the surfaces of the plurality of fibers 61. Spreading refers to changing a bundle of fibers into a loose (loose) state.

[0028] This resin gear molding material 6 is a fiber ball that is soft and expandable. The bulk density of the resin gear molding material 6 is 0.03 to 0.05 g / mL. To measure the bulk density, for example, a dry 100 mL measuring cylinder (minimum graduation: 1 mL) can be used. First, measure the weight M0 of the empty measuring cylinder. Because the measurement target aggregates, the target is placed in the 100 mL measuring cylinder while passing it through a sieve with 8.0 mm openings to break down the aggregates. This operation is performed gently so as not to change the properties of the target. After placing the target into the measuring cylinder to a height of 90 to 100 mL, carefully smooth the top surface of the target without compacting it, if necessary, and read the loose bulk volume V0 to the minimum graduation. Then, measure the weight M1 of the target placed in the 100 mL measuring cylinder. The weights M0 and M1 are measured with an accuracy of 0.1 g. Finally, the bulk density (g / mL) is calculated according to the following formula. In this embodiment, the bulk density of the produced resin gear molding materials 6 is measured to be any value between 0.03 and 0.05 g / mL. As specific examples, the bulk density of the resin gear molding materials 6 is measured to be 0.0337 g / mL, 0.0411 g / mL, and 0.0444 g / mL. (Weight M1 - Weight M0) / Loose bulk volume V0

[0029] Next, the resin gear 1 is manufactured using the resin gear molding material 6. Specifically, a metal bushing 8 is placed in the center of a mold, and the resin gear molding material 6 is filled around the metal bushing 8. The resin gear molding material 6 is heated and compressed to harden the resin contained in the resin gear molding material 6 and form a resin member 9.

[0030] The resin member 9 is cut to adjust the dimensions of the resin member 9. For example, a molded product is cut using a machine tool such as a lathe. After cutting the resin member 9, the resin member 9 is washed. Gear cutting of the resin member 9 is performed. Examples of gear cutting that can be applied include finishing using a hobbing machine or a shaving machine. As a result, a tooth profile 9a is formed in the resin member 9. Through the above steps, the resin gear 1 is manufactured.

[0031] Next, a specific example of mixing the raw materials 5 by the mixer 10 in the manufacturing method according to this embodiment will be described.

[0032] A raw material 5 is prepared, which contains short fibers in an amount that makes the total amount in the resin gear molding material 6 40 wt %, resin powder 2 in an amount that makes the total amount in the resin gear molding material 6 59 wt %, and additives 4 in an amount that makes the total amount in the resin gear molding material 6 1 wt %.

[0033] Specifically, wet fibers 3 with a moisture content of 20% by weight are used as fiber chops to be used as short fibers. The fiber chops are made up of 40% by mass of para-aramid fiber with an aspect ratio of 200 (manufactured by Teijin Limited, "Technora (registered trademark)") and 55% by mass of meta-aramid fiber with an aspect ratio of 200 (manufactured by Teijin Limited, "Conex (registered trademark)") respectively. As resin powder 2, phenolic resin powder with a particle diameter of 20 μm (manufactured by Air Water Bellpearl Inc., "Bellpearl (registered trademark)") is weighed. As additive 4, montanic acid ester (manufactured by Clariant Japan, "LICOWAX OP") is weighed.

[0034] An Einrich mixer is used as the mixer 10. The raw material 5 is charged into the mixing pan 12 of the Einrich mixer. The total amount of raw material 5 charged into the mixing pan 12 is 40 g / L relative to the volume of the mixing pan 12. After the raw material 5 is charged into the mixing pan 12, mixing is performed for 10 minutes under conditions of a rotor 13 rotation speed of 3000 rpm and a mixing pan rotation speed of 84 rpm. As a result, the resin powder 2 adheres to the short fibers of the wet fibers 3, forming cocoon-shaped balls with an aspect ratio of approximately 1.8 and a bulk density of approximately 0.04 g / cm. 3It was possible to produce a resin gear molding material 6, which is a fiber ball.

[0035] As described above, in the method for producing a resin gear molding material 6, by mixing the raw material 5 for a predetermined time using the mixer 10, the resin powder 2 can be adhered to the surface of the wet fibers 3 without being heated and melting the resin powder 2. Furthermore, using wet fibers 3 with a moisture content of 10 to 25% as the raw material 5 prevents the resin powder 2 from falling off the surface of the wet fibers 3 (so-called powder fall). Therefore, the raw material 5 can be reliably granulated into a plurality of granular resin gear molding material 6 without promoting the curing reaction of the resin powder 2. This prevents a decrease in resin flow during molding using the produced resin gear molding material 6, making it possible to prevent poor resin impregnation in the molded resin member 9.

[0036] In the method for producing a resin gear molding material 6, a mixer 10 has a mixing pan 12 that contains raw materials 5 and a rotor 13 disposed within the mixing pan 12. By using such a mixer 10, it is possible to efficiently mix the raw materials 5 while achieving the above-mentioned effects.

[0037] In the method for producing the resin gear molding material 6, the wet fibers 3 may contain inorganic fibers. In this case, a resin gear molding material 6 having long fiber lengths can be easily obtained.

[0038] In the method for producing the resin gear molding material 6, the resin powder 2 may contain phenolic resin powder. In this case, the resin gear molding material 6 can be produced using phenolic resin as the thermosetting resin powder 2.

[0039] The method for manufacturing a resin gear 1 is a method for manufacturing a resin gear 1 having an annular resin member 9 using a resin gear molding material 6, and includes the steps of filling a metal mold (die) with the resin gear molding material 6 and heating and compressing the resin gear molding material 6 to form the resin member 9. In the method for manufacturing a resin gear 1, since the resin gear molding material 6 is used for molding, it is possible to prevent poor resin impregnation of the resin member 9.

[0040] The resin gear molding material 6 includes a fiber portion 60 containing a plurality of fibers 61, at least a portion of which is opened to form a ball-like outer shape, and thermosetting resin powder 62 attached to the surfaces of the plurality of fibers 61. The resin gear molding material 6 has a bulk density of 0.03 to 0.05 g / mL. By using this resin gear molding material 6 to manufacture the resin gear 1, it is possible to prevent poor resin impregnation of the resin member 9.

[0041] Figures 5(a) to 6(c) are photographs showing the relationship between the mixing time of raw material 5 and the mixing results. Each of Figures 5(a) to 6(c) shows the results of mixing raw material 5 under the conditions of the specific example described above, for each mixing time. When the mixing time is 30 seconds, there is unopened fiber residue, as shown in Figure 5(a). When the mixing time is 60 seconds, there is unopened fiber residue, as shown in Figure 5(b), but the amount of fiber residue is reduced compared to the result in Figure 5(a).

[0042] When the mixing time is 2 minutes, as shown in FIG. 6(a), the fibers no longer appear unopened on the outside, but there are unopened fibers remaining inside the three-dimensional (lumpy) portions. When the mixing time is 5 minutes, as shown in FIG. 6(b), the fibers no longer appear unopened on the outside, and there are almost no unopened fibers remaining inside the three-dimensional portions. When the mixing time is 10 minutes, as shown in FIG. 6(c), the fibers no longer appear unopened on the outside, and there are no unopened fibers remaining inside the three-dimensional portions. Therefore, in this embodiment, the mixing time (predetermined time) for mixing the raw material 5 is preferably 5 minutes or more, and more preferably 10 minutes or more.

[0043] Generally, pelletized resin gear molding materials are obtained by kneading fibers and a thermosetting resin using, for example, a roll mixer or kneader. However, molding using such resin gear molding materials can lead to grain boundary cracks in molded articles (e.g., resin components of resin gears), potentially reducing the strength of the molded articles. Therefore, there is a need to provide a resin gear molding material that can prevent a reduction in the strength of molded articles, as well as a method for manufacturing a resin gear using the same. In response to this need, a resin gear molding material 6 according to one embodiment is a molding material for resin gears, as described above. The molding material 6 includes a plurality of fibers 61, at least a portion of which is spread to form a three-dimensional fiber portion 60, and a thermosetting resin powder 62 attached to the surfaces of the plurality of fibers 61. The bulk density of the molding material is 0.03 to 0.05 g / mL. When this resin gear molding material 6 is used for molding, the fibrous parts 60 tend to intertwine with each other, which makes it possible to suppress the occurrence of grain boundary cracks in the molded product and to prevent a decrease in the strength of the molded product.

[0044] Although the embodiments have been described above, one aspect of the present invention is not limited to the above embodiments.

[0045] In the above embodiment, in the second step of mixing the raw materials 5 in the mixer 10 to form the resin gear molding material 6, water may be added to the raw materials 5 during mixing using a sprayer or the like. This allows the moisture content of the raw materials 5 to be adjusted in the second step, and makes it possible to further prevent the resin powder 2 from falling off the surface of the wet fibers 3.

[0046] In the above embodiment, instead of wet fibers 3 having a moisture content of 10 to 25% by weight, fibers and water that realize such wet fibers 3 may be used. Note that when wet fibers 3 having a moisture content of less than 10% by weight or fibers and water that realize such wet fibers 3 are used, the resin powder 2, 62 in the resin gear molding material 6 tends to fall off significantly. When wet fibers 3 having a moisture content of more than 25% by weight or fibers and water that realize such wet fibers 3 are used, the resin powder 2, 62 becomes clay-like and sticks to the wall of the mixing pan 12, making uniform mixing difficult. When wet fibers 3 having a moisture content of more than 50% by weight or fibers and water that realize such wet fibers 3 are used, uniform mixing becomes even more difficult.

[0047] In the above embodiment, the resin gear 1 may include an elastic member disposed between the metal bushing 8 and the resin member 9 to attenuate impacts. In the above embodiment, the resin gear 1 is a spur gear, but the resin gear 1 may be a helical gear or the like. In the present invention, the configurations of the above embodiment and the above modified examples may be combined as appropriate. The present invention can be modified in various ways without departing from the spirit and scope of the invention. [Explanation of symbols]

[0048] 1...resin gear, 2...resin powder, 3...wet fiber, 5...raw material, 6...molding material for resin gear, 9...resin part, 10...mixer, 12...mixing pan (container), 13...rotor (agitating blade), 60...fiber part, 61...fiber, 62...resin powder.

Claims

1. A method for producing a molding material for a resin gear, comprising the steps of: A first step of preparing a raw material including a thermosetting resin powder and a wet fiber having a moisture content of 10 to 25% by weight, or a fiber and water that realizes the wet fiber; a second step of mixing the raw materials for a predetermined time using a mixer to form a plurality of granular molding materials for a resin gear; The method for producing a molding material for a resin gear, wherein the wet fiber or the fibers include at least one of meta-aramid fiber, para-aramid fiber, cellulose fiber, phenolic resin fiber, and polyimide fiber.

2. 2. The method for producing a molding material for a resin gear according to claim 1, wherein the wet fiber or the fibers have a fiber length of 1 to 6 mm.

3. A method for producing a molding material for a resin gear, comprising the steps of: A first step of preparing a raw material including a thermosetting resin powder and a wet fiber having a moisture content of 10 to 25% by weight, or a fiber and water that realizes the wet fiber; a second step of mixing the raw materials for a predetermined time using a mixer to form a plurality of granular molding materials for a resin gear; The resin powder includes an imide resin powder.

4. The mixer comprises: A container for containing the raw material; 4. The method for producing a molding material for a resin gear according to claim 1, further comprising: a stirring blade disposed in the container for stirring the raw material.

5. 4. The method for producing a molding material for a resin gear according to claim 1, wherein in the second step, water is added to the raw materials during mixing.

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