JP2014240170A - Method of producing resin-made gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing a resin-made gear composed of dissimilar material layers which suppresses detachment of a dissimilar material layer in the laminate boundary and prevents deterioration of the life of the gear even when changes of teeth occur.SOLUTION: A method of producing a resin-made gear includes a first step of carrying out twice or more, in a wet state, a step of charging a slurry which contains at least a short fiber and a powder resin as constituents and is prepared by mixing the constituents with water, into a preliminarily molding die, and discharging water to accumulate the constituents in the preliminary molding die so as to form an accumulation layer, a second step of compressing, in the thickness direction, a plurality of the accumulation layers obtained by carrying out the step of forming the accumulation layer twice or more to form a molding blank, a third step of molding the molding blank with heating and pressing to form a resin molding, and a fourth step of processing the resin molding into a tooth part of an oblique-tooth gear. The constituent ratio of individual constituents and/or the types of the constituents are modified between both accumulation layers so that the accumulation layer on the side where an asymmetrical contact of the resin-made gear with a counter gear to be engaged in occurs is higher in strength than the accumulation layer on the other side.

Description

  The present invention relates to a method of manufacturing a resin gear, and in particular, an oblique-tooth resin gear.

Conventionally, many gears used in automobiles have used metal parts in terms of strength and heat resistance. However, in recent years, environmentally-friendly automobile development has progressed, and the weight has been reduced to improve fuel economy and reduce CO ₂ emissions. Furthermore, from the viewpoint of quietness of the meshing sound between the metal gears, it is suggested to use a resin gear.

  As a specific configuration of the resin gear, there is one using an aramid fiber as a reinforcing fiber base, and a reinforcing fiber base 1 formed in a donut shape as shown in FIG. A resin molded body 3 is produced by impregnating and curing the base material 1 with a resin. Patent Document 1 discloses a method of cutting gears around the resin molded body 3 to produce a resin gear.

However, in this prior art, two reinforcing fiber bases 1 formed in a donut shape are sandwiched by using two metal bushes 2 to prevent the metal bushes 2 from coming off. The fiber entanglement is weak at the interface, and the durability of the resin gear may be insufficient depending on the intended use. In order to solve these problems, Patent Document 2 discloses a method of producing a fiber aggregate by filtration dehydration using short fibers and producing a reinforcing fiber substrate.
In addition, the resin gear often uses an inclined gear as a gear form for improving the quietness, and the quietness is improved by improving the meshing rate.

JP 2001-295913 A JP 2009-250364 A JP-A-11-227061

However, when used as an automobile part, the ambient temperature in the usage environment often increases to around 100 ° C., so that a dimensional change due to a temperature change occurs.
More specifically, FIG. 2 shows a side view of a resin bevel gear viewed vertically from the tooth tip. The tooth trace 4 (solid line) in the normal temperature (25 ° C.) region and the high temperature region There is a change in the tooth trace 5 (broken line).

  The transition of the tooth trace due to the temperature change described above does not appear to be a significant problem when viewed with the resin gear alone. However, the gear functions only when there is a counter gear, and this change due to temperature change cannot be ignored.

The mating gear that meshes with the resin gear is often made of metal, and the resin and metal have different linear expansion coefficients and different amounts of gear teeth.
FIG. 3 shows a schematic diagram of meshing in the normal temperature (25 ° C.) region. When the metal gear 6 that is the counterpart gear and the resin gear 7 are meshed with each other, the tooth trace 8 of the metal gear and the resin gear The tooth trace 9 of the gear is designed to have a meshing range that matches.
Next, FIG. 4 shows a schematic diagram of meshing in a high temperature range. Due to the dimensional change due to temperature, the meshing tooth contact changes from normal temperature (25 ° C.), and the tooth trace 8 of the metal gear and the resin gear. One-sided engagement occurs only on one side of the tooth muscle 9. As a result, the meshing rate is lowered, which is disadvantageous for resin gears, and there is a possibility that gear breakage may occur at an early stage.

Here, Patent Document 3 discloses a resin-made gear that is formed by stacking a plurality of paper-making sheet bodies obtained by press-extruding a paper-making sheet mainly composed of a thermosetting resin and short fibers, and heat-press-molding in a molding die. The manufacturing method of is described. At this time, a sheet-forming sheet body made of different materials is laminated in a predetermined combination configuration, and given desired characteristics to a predetermined site in the tooth width direction by heating and pressing in a molding die. Can be considered.
However, the resin gear described above has almost no entanglement of short fibers at the lamination interface of the papermaking sheet body, and there is a concern that peeling is likely to occur on the lamination surface depending on the intended use.

  Even if the present invention is a resin gear composed of different material layers, peeling is unlikely to occur at the laminated interface of the different material layers, and the change of tooth traces is caused by the temperature change from the normal temperature range to the high temperature range. Responding to various phenomena, such as when it occurs, is to produce a resin gear that does not shorten the life of the gear.

In order to solve the above problems, the resin gear according to the present invention employs the following configuration.
(1) A slurry prepared by mixing at least short fibers and a powdered resin as a constituent and mixing the constituent and water is put into a preforming mold, and water is discharged from the preforming mold, A first step of performing a process of accumulating the components in a preform mold to form an integrated layer a plurality of times in a wet state; and a plurality of integrated layers obtained by performing the process of forming the integrated layer a plurality of times A second step of forming a molding material by compressing the molding material in a thickness direction, a third step of forming a resin molding by heating and press-molding the molding material, and forming the resin molding of an inclined gear A method of manufacturing a resin gear that undergoes a fourth step that is processed into a tooth portion, in which an integrated layer on a side where one piece of the resin gear comes into contact with a mating gear is stronger than an integrated layer on the other side. So that the composition ratio of each component between the two integrated layers and Or wherein varying the type of arrangement.
(2) In the item (1), the composition includes both short fibers having relatively high strength and short fibers having low strength. It is characterized in that the composition ratio of high-strength short fibers is increased from that of lamination.
(3) Item (1) is characterized in that the content ratio of the short fibers is increased in the integrated layer on the side where the one-piece contact occurs than in the integrated layer on the other side.

According to the present invention, the process of collecting at least the short fibers and the powdered resin as constituents in the preform mold and accumulating the constituents to form an integrated layer is performed a plurality of times in a wet state. The integrated layer is compressed in the thickness direction to form a molding material. Therefore, the compression can impart entanglement of short fibers to the lamination interface of the plurality of integrated layers, and even a resin gear composed of different material layers can be peeled off at the lamination interface of different material layers. It can be made difficult to occur.
Also, the composition ratio of each component and / or the type of the component is set so that the strength of the integrated layer on the side where the one-sided contact of the resin gear with respect to the meshing gear is larger than that of the other integrated layer. By making it different, for example, the type of resin, short fiber, resin and short fiber is changed or the type of resin, short fiber, resin and short fiber is the same, but the ratio By changing the strength of the resin gear, it is possible to suppress a reduction in the service life of the resin gear due to contact with each other. In addition, inexpensive layers can be used for layers other than the one where contact occurs, and the overall cost can be reduced.

  For example, the strength can be increased by increasing the composition ratio of relatively high-strength short fibers in the integrated layer on the side where one piece strikes, compared to the integrated layer on the other side. Further, the strength can be increased by increasing the content ratio of the short fibers in the integrated layer on the side where the one-piece contact occurs than in the integrated layer on the other side.

The manufacturing process of the resin gear which is a prior art example is shown. It shows changes in tooth muscles due to temperature changes. A schematic diagram of meshing at room temperature is shown. The meshing outline figure in a high temperature range is shown. The outline figure of manufacture of the molding material which has a plurality of accumulation layers is shown. An example of a resin gear provided with two integrated layers is shown. A schematic diagram of a molding die is shown. The Example of the resin gear provided with the three layers of accumulation layers is shown. The schematic diagram of preparation of the papermaking sheet | seat body of the comparative example 2 is shown. The outline figure of cleavage strength measurement is shown.

  In the present invention, at least the short fibers and the powdered resin are included as a constituent of the accumulation layer. In addition, inorganic powder or the like may be included.

<Short fiber>
The short fibers used in the present invention are not particularly limited, but natural fibers such as cotton and hemp, organic fibers such as aramid fibers (aromatic polyamide fibers) and polyamide fibers, carbon fibers, glass fibers, and metal fibers. Inorganic fibers such as can be appropriately used depending on the intended use. These short fibers may be used alone or in a plurality of types depending on the application. Among them, high-strength short fibers, specifically, organic fibers mixed with para-aramid fibers and meta-aramid fibers, and inorganic fibers with short glass fibers, workability and machinability, heat resistance, It is superior in terms of gear strength and is particularly preferable.

  The fiber length of the short fibers used in the present invention is not particularly limited, but is preferably 2 to 6 mm. When the fiber length is shortened, the entanglement between the short fibers becomes weak, and it becomes difficult to secure the strength required for the resin molded body. When the fiber length is increased, the dispersibility of the short fibers is reduced when preparing a slurry for filtration and dehydration. By setting the fiber length within the above range, the strength required for the resin molded body can be ensured, and the dispersibility of the fibers becomes sufficient when preparing a slurry for filtration dehydration.

<Powdered resin>
The resin used in the present invention is provided in a powder form (including a particle form), and various materials such as a thermosetting resin and a thermoplastic resin can be used. For example, epoxy resin, polyaminoamide resin, phenol resin, unsaturated polyester resin, polyimide resin, polyethersulfone resin, polyetheretherketone resin, polyamideimide resin, polyamide resin, polyester resin, polyphenylene sulfide resin, polyethylene resin, polypropylene A combination of one or more resins selected from resins can be used. Among these, a phenol resin is preferable from the viewpoints of the strength and heat resistance of the cured resin.
The particle shape of the powdery resin is arbitrary, but a granular resin is preferably used. Moreover, although a particle diameter changes with fiber diameters of a short fiber, 50 micrometers or less are preferable. Thereby, it can distribute uniformly in the gap | interval of the short fibers of the short fiber accumulation body. When the particle size is large, the fiber orientation of the short fiber aggregate may be disturbed, and when the resin molded body is manufactured by heat and pressure molding, the short fibers and the resin inside the resin molded body are not uniformly distributed. It can be a cause.

A slurry prepared by mixing at least the above-mentioned short fibers, powdered resin and water is filtered and dehydrated to form a plurality of layers of short fibers and powdered resin. Next, the plurality of integrated layers are compressed in the thickness direction to form a molding material. Then, the molding material is heated and pressed to form a resin molded body.
At this time, in the present invention, adjacent stacked layers have different composition ratios or constituents of the resin and the filler. Specifically, the resin itself is different, the fillings such as short fibers are different, both the resin itself and the filling are different, the filling is the same but the filling ratio is different, or the resin itself and the filling ratio are different. , That means.
In the present invention, carbon powder, glass powder, molybdenum disulfide, alumina, boron nitride, iron powder, and the like may be used in combination as fillers other than short fibers.

For example, adjacent stacked layers can be made of different types of short fibers or different short fiber compositions.
More specifically, when only organic fibers are used, for example, when at least one of the integrated layers is composed of organic fibers A, the other integrated layers are organic fibers B or a mixed composition of organic fibers A and organic fibers B. Can be.
When only inorganic fibers are used, for example, when at least one layer of the accumulation layer is composed of inorganic fibers, the other accumulation layer can be composed of inorganic fibers or a mixture of inorganic fibers and inorganic fibers. .

  When organic fibers and inorganic fibers are used in combination, for example, at least one layer of the accumulation layer is made of organic fibers or inorganic fibers, and the other accumulation layer is made of short fibers different from the organic fibers or inorganic fibers. If each of the plurality of integrated layers contains organic fibers and inorganic fibers, at least one layer is made of a mixed composition of organic fibers A and inorganic fibers A, and the other integrated layers are designated as “organic fibers B or organic. "Mixed composition in which inorganic fiber A is blended with fiber A and organic fiber B", "Mixed composition in which inorganic fiber b is blended in organic fiber B or organic fiber A and organic fiber B", "Organic fiber B, Or the mixed composition which mix | blended the inorganic fiber A and the inorganic fiber B in the organic fiber A and the organic fiber B "or" the mixed composition which mix | blended the organic fiber A in the inorganic fiber B or the inorganic fiber B and the inorganic fiber B ".

The layer described as “at least one layer” described above is a layer in which an undesired phenomenon occurs, for example, contact with each other in a high-temperature atmosphere. In order to increase the strength, para-aramid fibers and meta-based fibers are used. It is preferable to use a mixture of aramid fibers, and it is preferable to use short glass fibers if they are inorganic fibers.
In the above, the case where adjacent stacked layers have different types of short fibers or different short fiber compositions has been described in detail, but adjacent stacked layers have different types of fillers or different filler compositions. In the case of, the same can be carried out.

<Short fiber content>
The content ratio of the short fibers is not particularly limited, and the mass ratio of the short fibers contained in the accumulation layer and the short fibers in the total mass of the powdered resin is the same in all the accumulation layers. May be different.

When different mass ratios are used, this different layer is a part where defects such as per piece appear, and the proportion of short fibers is increased. Specifically, the mass ratio of short fibers in different layers is preferably 40 to 60%, and the mass ratio of short fibers in other layers is preferably 35 to 50%.
In addition, when the mass ratio of the short fibers is less than 35%, the strength tends to gradually decrease, and when it exceeds 60%, the resin melted at the time of heat and pressure molding does not flow to the entire resin molded body, and the resin The incidence of the impregnated portion is increased. If the mass ratio of the short fibers is within the above range, the strength required for the resin molded body can be ensured, and the rate of occurrence of insufficient resin impregnation (defective) can be reduced.

<Thickness of accumulation layer>
The thickness of each integrated layer in the resin molded body is not particularly limited, and all layers may have the same thickness, or at least one layer thickness may be changed as compared with other layers.
In the case where the thicknesses of the integrated layers are made different, the layers having different thicknesses are portions where defects such as one piece appear, and the thickness of the integrated layer can be made thicker than other layers.
The thickness of the accumulation layer is appropriately selected depending on the tooth width of the resin gear. Specifically, the thickness of the entire tooth width can be set to 100%, and the thickness of the integrated layer where defects may appear can be set to 30 to 50%.

<Structure of integrated layer>
The configuration of each integrated layer is not particularly limited, but it is preferably an odd layer, and it is preferable to provide the same integrated layer symmetrically across the central integrated layer in order to prevent warping of the resin molded body.

<Manufacture of resin molding>
The production of the resin molded body is not particularly limited. For example, an apparatus having a function as shown in FIG. 5 can be used.

  First, the necessary short fibers and powdered resin are prepared for each of the plurality of integrated layers, and the mass of the necessary short fibers and powdered resin is measured for each layer to prepare the short fibers and the powdered resin. A short fiber and powdered resin for one layer are put in a specified amount of water, and the short fiber and powdered resin are stirred to prepare a slurry. In order to produce an accumulation layer of short fibers and powdered resin, the prepared slurry is poured into a preforming mold in which a metal bush 2 is set in advance, and the short fibers and powdered resin are deposited in the preforming mold. An integrated layer 10 of eyes is produced. Subsequently, when the accumulation layer is in a wet state, short fibers and a powdered resin necessary for the next accumulation layer are prepared, a slurry is prepared in the same procedure, and the short fibers are poured into the preforming mold again. A powdery resin is deposited to produce the second integrated layer 11. This operation is repeated for the necessary integrated layers.

At this time, if the slurry for the next layer is put into the preforming mold after the slurry for one layer is put into the preforming mold and then the water is discharged from the preforming mold, Because there is no water to absorb the impact when the is injected into the preforming mold, the upper layer of the previous layer is disturbed by the slurry of the next layer, so the boundary between the previous layer and the next layer As a result, the interlaminar strength between the previous integrated layer and the next integrated layer can be improved.
In addition, after the slurry for one layer is put into the preforming mold, when the slurry of the next layer is put into the preforming mold with water still remaining in the preforming mold, the preforming mold Since the next integrated layer can be obtained without disturbing the fiber orientation of the previous integrated layer integrated therein, a molding material in which the boundary between the previous integrated layer and the next integrated layer is separated can be obtained.

The preforming mold includes a cylindrical mold 12 for determining the outer diameter of the molding material, bush support portions 13 and 14 for fixing the metal bush 2 inside the cylindrical mold, and accumulated short fibers. And an apparatus having compression molds 15 and 16 for compressing the powdered resin. The compression mold 16 is provided with a through hole 17 for draining only slurry water, and short fibers and powdered resin are prevented from coming out of the through hole 17 on the compression mold 16. A mesh 18 is placed, and only moisture is drained while the short fibers and the powdery resin are deposited on the mesh 18.
After the necessary accumulation layer is deposited in the preforming mold, the accumulation layer is compressed by the compression molds 15 and 16 mounted on the preforming mold to perform dehydration and shape formation, and a plurality of accumulation layers A molding material 19 having

Next, the produced molding material 19 is set in a molding die and subjected to heat and pressure molding to produce a resin molded body.
In addition, the resin gear is manufactured by cutting the periphery of the resin molded body to form teeth, thereby producing a resin gear.

Embodiments of the present invention will be described below with reference to the drawings.
Example 1
In Example 1, a resin gear having two integrated layers having the same thickness as shown in FIG. 6 is produced.
That is, the accumulation layer 20 constituting the molding material 19 includes a powdery resin, meta-aramid fiber and para-aramid fiber which are organic fibers as constituents.
The accumulation layer 20 is 50% by mass of meta-aramid fiber A (fiber length: 3 mm, fiber diameter: 10 μm) and 45% by mass of para-aramid fiber B (fiber length: 3 mm, fiber diameter: 10 μm) as short fibers. Para-aramid fiber C (fiber length: 6 mm, fiber diameter: 10 μm) was mixed and used in an amount of 5% by mass. Moreover, phenol resin powder having a particle diameter of 20 μm was used as the powdery resin. And the short fiber and powdery resin were prepared so that the fiber total amount of the short fiber in a resin molding might be 49 mass%.
The respective short fibers and powdered resin used for the accumulation layer 20 are put in water and stirred to prepare slurry A. The amount of water was adjusted so that the slurry concentration at this time was 4 g / liter with respect to the total mass of the short fibers and the powdered resin.

Further, as the accumulation layer 21 (see FIG. 6), as a constituent, a powdered resin, a meta-aramid fiber that is an organic fiber, a para-aramid fiber, and a glass fiber that is an inorganic fiber for strength improvement are included. To do.
The accumulation layer 21 is 50% by mass of meta-aramid fiber A, 40% by mass of para-aramid fiber B, 5% by mass of para-aramid fiber C as short fibers, and glass fiber D (fiber length: 0 as inorganic fiber). .12 mm, fiber diameter: 12 μm) was used by mixing 5% by mass. Moreover, phenol resin powder having a particle diameter of 20 μm was used as the powdery resin.
The respective short fibers and powdered resin used for the accumulation layer 21 are put in water and stirred to prepare slurry B. The amount of water was adjusted so that the slurry concentration at this time was 4 g / liter with respect to the total mass of the short fibers and the powdered resin.

  Next, the metal bush 2 is set on the bush support 14 of the preforming mold shown in FIG. 5, and the slurry A used for the accumulation layer 20 is first put into the preforming mold. The cylindrical mold 12 and the bush support portions 13 and 14 constituting the preforming mold constitute the outer diameter and inner diameter shape of the integrated layer. In this embodiment, the inner diameter portion of the cylindrical mold 12 is used. The diameter was 82 mm, and the outer diameters of the bush support portions 13 and 14 were 55 mm. Further, vacuum suction is performed from the lower side of the through-hole 17 to drain water, and a deposit that becomes a base of the accumulation layer 20 of short fibers and powdered resin is produced. Next, the slurry B used for the accumulation layer 21 is put into a preforming mold. The timing at which the slurry B was introduced was such that the water of the slurry A introduced into the preforming mold still remained in the preforming mold.

  At this time, in order to make the integrated layers 20 and 21 have the same thickness, the mass of the deposit of the integrated layer 21 is adjusted so as to be the same as that of the integrated layer 20, Similarly, a deposit as a basis of the integrated layer 21 is produced.

  After producing the two-layered deposit, the upper compression mold 15 is lowered in the axial direction of the metal bush 2 until the distance between the compression molds 15 and 16 becomes 35 mm. At this time, the bush support portions 13 and 14 move in conjunction with each other, and the center portion of the metal bush 2 is maintained at the center of the compression molds 15 and 16. By continuing this state for 1 minute, the molding material 19 (see FIG. 5) composed of the integrated layers 20 and 21 is produced.

  Next, the molding material 19 is placed in the molding die 22 heated to 200 ° C. shown in FIG. 7A, the molding die 22 is closed as shown in FIG. 7B, and the molding material 19 is heated. Press molding to cure the powdered resin to obtain a resin molded body. If the resin is not sufficiently cured, a post-heating step may be applied as necessary to ensure that the resin is cured. The resin molded body was cut using a hobbing machine to form teeth, thereby obtaining a resin gear.

(Example 2)
In Example 1, except that the timing of supplying the slurry B was after the water of the slurry A introduced into the preforming mold was removed by vacuum suction, the resin gear was the same as in Example 1. Got.

Example 3
In Example 1, the same as Example 1 except that the accumulation layer 23 in which the short fiber blending mass ratio (short fiber composition) of the accumulation layer 21 was changed to A / B / C = 55/40/5 was used. Thus, a resin gear was obtained.

Example 4
In Example 1, the short layer used for the stacking layer 20 is only the carbon fiber E (fiber length: 3 mm, fiber diameter: 18 μm), and the short fiber used for the stacking layer 21 is carbon fiber E. A resin gear was obtained in the same manner as in Example 1 except that the accumulation layer 25 having a mixed composition in which the mass blending ratio of the glass fiber D and the glass fiber D was 60/40 was used.

(Example 5)
In Example 4, a resin gear having three integrated layers as shown in FIG. 8 and having the same short fiber composition on both sides of the central integrated layer is used.
The manufacturing method is the same as that in Example 1, and the integrated layer 20 composed of the organic fibers used in Example 1 shown above is used as the first and third layers as the integrated layer to be used. As an example, the integrated layer 25 made of inorganic fibers used in Example 3 is used.
In Example 4, the total fiber amount of the short fibers in the resin molded body in the accumulation layer 20 was adjusted to 50 mass%. Moreover, it adjusted so that the fiber total amount of the short fiber in the resin molding in the integration | stacking layer 25 might be 40 mass%.

(Comparative Example 1)
Example 1 is the same as Example 1 except that only the slurry A was put into a preforming mold to produce a molding material composed of a single layer of the integrated layer 20 (without the laminated structure of the integrated layer). In the same manner, a resin gear was obtained.

(Comparative Example 2)
The papermaking sheet | seat was created using the papermaking apparatus 307 shown in FIG. The papermaking apparatus 307 includes a bottom surface portion 313 and a rectangular tube-forming cylinder 309. Only the bottom surface portion 313 is made of a wire mesh. The wire mesh used was a 20 mesh sheet wire mesh. And the slurry A used in Example 1 was introduce | transduced into the papermaking apparatus 307, it spin-dry | dehydrated, and the papermaking sheet 310 was obtained. The papermaking sheet 310 was punched into a ring shape having an outer diameter of φ82 mm × an inner diameter of φ55 mm and dried to obtain a papermaking sheet body 308. Further, in the same manner as described above, a paper-making sheet body 308 ′ was obtained using the slurry B used in Example 1.
Using the sheet-forming sheet bodies 308 and 308 ′ obtained in the above-described process, the protrusion provided on the metal bush is sandwiched, placed in a heated molding die, and clamped. Subsequent steps were performed in the same manner as in Example 1 to obtain a resin gear.

(Cleavage strength evaluation)
A test piece having the shape shown in FIG. 10 was cut out from the resin molded bodies obtained in Examples 1 to 5 and Comparative Examples 1 and 2, and the center of the test piece (surface intersecting with the stacking direction of the accumulation layer) was steel having a diameter of 10 mm. The load was measured when the test piece was cleaved by applying pressure with a ball.
The test results were obtained as shown in Table 1 below, and when the relative evaluation was made assuming that the result of the resin molded body of Comparative Example 1 having no stack structure of the integrated layer is 1, in Example 1, the test was performed 1.0 times. Example 2 was 1.2 times, Example 3 was 1.0 times, Example 4 was 1.0 times, Example 5 was 1.0 times, and Comparative Example 2 was 0.8 times. The advantage of Example 2 is that the timing at which the slurry used for the accumulation layer 21 is put into the preforming mold is performed in a wet state after water is discharged from the preforming mold. It is presumed that the fiber orientation at the boundary between the accumulation layer and the next accumulation layer was disturbed, and the orientation was advantageous for cleavage strength. Moreover, in the comparative example 2, it is estimated that there is almost no short fiber entanglement in the lamination | stacking interface of a papermaking sheet | seat body, and peeling is easy to generate | occur | produce on a lamination surface.

(Durability test evaluation)
In the resin gears obtained in Examples 1 to 5 and Comparative Examples 1 and 2, the life of the resin gears was evaluated using a durability tester. As a method, a continuous rotation test was performed under acceleration evaluation conditions (mating gear: metal gear, oil temperature: 130 ° C., rotation speed: 6000 rpm, tooth root stress: 160 MPa), and the time until the resin gear was damaged was evaluated.
The test results were obtained as shown in Table 2 below. When the relative evaluation was made with the result of the resin gear of Comparative Example 1 having no stack structure of the integrated layer as 1, the implementation in Example 1 was 1.4 times. Example 2 was 1.3 times, Example 3 was 1.1 times, Example 4 was 1.2 times, and Example 5 was 2.3 times. It is presumed that the reason why Example 5 is superior is that both low elasticity (impact absorption), which is an advantage of organic fibers, and strength retention, which is an advantage of inorganic fibers, are compatible.

(Gear strength evaluation)
In the resin gears obtained in Examples 1 to 5 and Comparative Examples 1 and 2, the gear strength was confirmed. As a method, with the resin gear meshed with a fixed metal gear, the resin gear is rotated so that the peripheral speed on the reference pitch circle is 0.33 mm / min, and the tooth portion is destroyed. The load was measured.
The test results are obtained as shown in Table 3 below, and when the relative evaluation is made assuming that the result of the resin gear of Comparative Example 1 having no laminated structure is 1, it is 1.2 times in Example 1, and in Example 2. 1.2 times, 1.1 times in Example 3, 1.6 times in Example 4, and 1.4 times in Example 5. It can be presumed that this is due to a large content of inorganic fibers that are superior in strength and hardness.

DESCRIPTION OF SYMBOLS 1 ... Reinforcement fiber base material, 2 ... Metal bush, 3 ... Resin molded object, 4 ... Tooth trace in normal temperature range, 5 ... Tooth trace in high temperature range, 6 ... Metal gear, 7 ... Resin gear, 8 ... teeth of metal gear, 9 ... teeth of resin gear, 10 ... first layer of accumulation layer, 11 ... second layer of accumulation layer, 12 ... cylindrical mold, 13, 14 ... bush support, 15 , 16 ... compression mold, 17 ... through hole, 18 ... mesh, 19 ... molding material, 20 ... integration layer, 21 ... integration layer, 22 ... molding die, 23 ... integration layer, 24 ... integration layer, 25 ... Integration layer

Claims (3)

A slurry prepared by mixing at least short fibers and a powdered resin as a component and mixing the component and water is put into a preforming mold, and water is discharged from the preforming mold, thereby performing the preforming mold. A first step of performing the process of accumulating the components in a mold to form an accumulation layer a plurality of times in a wet state;
A second step of forming a molding material by compressing a plurality of integrated layers obtained by performing the process of forming the integrated layer a plurality of times in the thickness direction;
A third step in which the molding material is heated and pressed to form a resin molded body;
A method of manufacturing a resin gear that undergoes a fourth step of processing the resin molded body into a tooth portion of an inclined gear,
The constituent ratio of each component and / or between the two integrated layers is such that the integrated layer on the side where the one-sided contact of the resin gear with respect to the mating gear is stronger than the integrated layer on the other side. Or the manufacturing method of the resin gear characterized by making the kind of structure differ.   The composition contains both short fibers having a relatively high strength and short fibers having a low strength, and the high-strength short fibers in the integrated layer on the side where the one-piece contact occurs than in the integrated layer on the other side. The method for producing a resin gear according to claim 1, wherein the composition ratio of the resin gear is increased.   2. The method of manufacturing a resin gear according to claim 1, wherein a content ratio of the short fibers is increased in the integrated layer on the side where the one-piece contact occurs compared to the integrated layer on the other side.