JP6907800B2 - Gearbox components and gearboxes, and methods for manufacturing gearbox components - Google Patents

Description

The present invention relates to a gearbox component, a gearbox, and a method for manufacturing the gearbox component.

In recent years, there has been a strong demand for the promotion of fuel efficiency for resource saving, energy saving, and CO _{2 reduction of automobiles.} Further weight reduction is required for the electric power steering device, and the possibility of reducing the weight of the components of the gear box that houses the reduction gear mechanism has been studied. However, in order to realize this, it is necessary to make major changes to the materials and structures that make up the gearbox. Generally, the components of this gearbox are made by pressing a metal such as an aluminum alloy.

For example, in the electric power steering device of Patent Document 1, the housing including the sensor housing for accommodating the steering state detection sensor and the gear housing for accommodating the speed reducer are all made of a resin material. According to this, the weight of the electric power steering device can be reduced. Further, in the electric power steering device of Patent Document 2, the housing member and the cover member of the gear box are manufactured by insert molding of a resin material in which a metal core metal is inserted.

JP-A-2009-298246 Japanese Unexamined Patent Publication No. 2013-67362

The weight reduction of the conventional gearbox component formed of the metal material can be achieved by forming the conventional gearbox component using a material having a lower specific density than the metal material, for example, a resin material. However, it is difficult to ensure the same strength and quality as the conventional product by simply replacing only the material. For example, there are problems such as delamination of the fiber sheet in the resin, variation in the amount of fiber in the fiber sheet, and lower impact resistance, creep characteristics, and rigidity as compared with the metal material. Further, when the metal material is replaced with a resin material, it is difficult to secure the same dimensional stability as the metal structure in the resin structure.

According to the electric power steering device of Patent Document 1, the sensor housing and the gear housing are all made of a polyamide resin material or a polyamide resin filled with reinforcing fibers, and both are integrally welded by a laser. However, in order to perform laser welding, the fiber content must be lowered, and there is a risk that physical properties such as high temperature strength, impact resistance, creep characteristics, and rigidity cannot always be sufficiently obtained.

Further, in the gear box of the electric power steering device of Patent Document 2, a resin composition containing a thermoplastic resin and a fiber reinforced material is fixed by inserting a bolt into a bolt hole of a core metal. However, in general, in injection molding, the reinforcing fibers are oriented in the flow direction of the material at the time of injection molding. Therefore, anisotropy occurs in the coefficient of thermal expansion in the flow direction of the material and the direction perpendicular to the flow direction thereof, which causes "warp" and tends to reduce the dimensional accuracy.

The present invention has been made in view of the above matters, and an object of the present invention is to provide a gearbox component and a gearbox which have high dimensional accuracy and can be reduced in weight while having the same strength and reliability as the conventional ones. Also, it is to provide a method of manufacturing gearbox components.

The present invention has the following configuration.
(1) A gearbox component that constitutes a gearbox in which a gear mechanism is housed.
A fibrous filler having an average fiber length of 0.5 mm or more is formed of a fiber-reinforced resin composition in which a fibrous filler is dispersed in the resin material .
It has a mother body and a protruding portion provided so as to project from a part of the mother body to the outside of the mother body.
The fibrous filler in the fiber-reinforced resin composition contained in the protruding portion is arranged so that the fiber longitudinal direction is aligned along the arc direction of bending on the outer surface of the protruding portion.
Gearbox components.
(2) A metal connecting member is embedded in at least a part of the above gearbox components.
A gearbox in which a plurality of the gearbox components are connected to each other by fastening members.
(3) There is a method for manufacturing gearbox components that make up a gearbox that houses a gear mechanism.
A fiber-spreading process in which a fibrous filler is opened in a solvent to obtain a fiber-containing slurry.
A papermaking process in which the fiber-containing slurry is injected into a papermaking mold, the solvent is removed from the papermaking mold, and a preform having substantially the same shape as the gearbox component is formed.
A molding step of loading the preform into a molding die, impregnating the preform with a resin material, and molding the gearbox component.
Have a,
The gearbox component has a mother body and a protruding portion provided so as to project from a part of the mother body to the outside of the mother body.
The papermaking mold has a main recess forming the base body and a branch recess branching from the main recess to form the protruding portion.
The papermaking process is
From the discharge path connected to the lower tip of the branch recess, only the solvent in the fiber-containing slurry injected into the branch recess is discharged out of the molding mold to be discharged into the fiber-containing slurry. The fiber longitudinal direction of the opened fiber is aligned along the arc direction of bending on the outer surface of the protruding portion.
How to manufacture gearbox components.

According to the present invention, the gear box in which the gear mechanism is housed can be configured to have high dimensional accuracy and weight reduction while having the same strength and reliability as the conventional one.

It is a schematic block diagram of an electric power steering apparatus. It is a partial cross-sectional view of line II-II shown in FIG. It is a partial cross-sectional view of the line III-III shown in FIG. (A) is a perspective view showing a schematic configuration of a gearbox cover, and (B) is a perspective view showing a schematic configuration of the back side of the gearbox cover shown in (A). It is a schematic perspective view of a papermaking mold for making a preform of a gearbox cover. FIG. 5 is a sectional view taken along line VI-VI of the lower mold shown in FIG. (A) and (B) are process explanatory views showing a state of producing a fiber-containing slurry in a fiber opening step. (A) to (E) are process explanatory views for explaining a papermaking process step by step. It is explanatory drawing which shows the flow direction of the fiber-containing slurry which flows into a boss forming part. It is a partially enlarged view which shows typically the boss of a gearbox cover.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Here, the gearbox in which the gear mechanism of the present invention is housed will be described as a gearbox used in the electric power steering device, but the present invention is not limited to this.

<Configuration of electric power steering device>
FIG. 1 is a schematic configuration diagram of an electric power steering device.
The electric power steering device 100 transmits the auxiliary output of the electric motor 11 to the steering mechanism 15 of the vehicle via the reduction gear mechanism 13. The electric power steering device 100 in the illustrated example is an example, and may be another type of mechanism.

In the electric power steering device 100 shown in FIG. 1, a steering shaft 17 in which a steering wheel (not shown) is fixed to an upper end portion is rotatably supported inside a housing 19 for a steering shaft. Further, the steering shaft housing 19 is fixed at a predetermined position inside the vehicle interior in a state where the lower portion thereof is inclined toward the front of the vehicle.

The rack and pinion mechanism 21 that converts the rotation of the steering shaft 17 into the movement of the left and right steering wheels is a tubular rack that supports a rack 23 that is movable in the axial direction, a pinion shaft 25, and the rack 23 and the pinion shaft 25. It is composed of a housing 27 for use. The pinion shaft 25 has a pinion that is supported obliquely with respect to the shaft core of the rack 23 and has gear teeth that mesh with the gear teeth of the rack 23.

The rack and pinion mechanism 21 is arranged substantially horizontally in the engine room at the front of the vehicle so that its longitudinal direction is along the width direction of the vehicle. Further, the upper end portion of the pinion shaft 25 and the lower end portion of the steering shaft 17 are connected by two universal joints 29 and 31. Further, steering wheels (not shown) are connected to both ends of the rack 23.

When the driver applies steering torque (rotational force) to the steering wheel, the steering shaft 17 rotates, and the steering torque is detected by a torque sensor attached to the steering shaft 17. Then, the output of the electric motor 11 (rotational force that assists steering) is controlled based on the detected steering torque. The output of the electric motor 11 is supplied to the intermediate portion of the steering shaft 17 via the reduction gear mechanism 13, combined with the steering torque, and converted into a motion of steering the steering wheels by the rack and pinion mechanism 21.

FIG. 2 is a partial cross-sectional view of line II-II shown in FIG. 1, and FIG. 3 is a partial cross-sectional view of line III-III shown in FIG.
As shown in FIGS. 2 and 3, the gear box 33 for accommodating the reduction gear mechanism 13 of the electric power steering device 100 attached to the vehicle body (not shown) is a bottomed tubular gear box main body shown in FIG. It is composed of 35 and a gearbox cover 37 (gearbox components). The gear box cover 37 closes the opening of the gear box main body 35 and is fixed to the gear box main body 35. That is, the bolt 39 is inserted into the opening provided on the gearbox cover 37 side and fastened to the screw hole provided on the gearbox body 35 side. As a result, the gearbox 33 in which the gearbox main body 35 and the gearbox cover 37 are integrated by fastening the bolts 39 is obtained.

Inside the gearbox 33, an intermediate steering shaft 47 is rotatably supported by rolling bearings 51 and 53. Further, a reduction gear mechanism 13 is housed inside the gear box 33, and a torque sensor 59 as a steering state detection sensor is housed.

The reduction gear mechanism 13 includes a worm wheel 55 shown in FIG. 2 and a worm shaft 57. The worm wheel 55 is fixed to the axial intermediate portion of the intermediate steering shaft 47 shown in FIG. Further, the worm shaft 57 shown in FIG. 2 is connected to the rotating shaft 61 of the electric motor 11 via a spline joint 63 and meshes with the worm wheel 55.

As shown in FIG. 3, the worm wheel 55 includes a disc portion 55a integrally rotatably fixed to the intermediate steering shaft 47, and synthetic resin teeth 55b formed on the outer diameter portion of the disc portion 55a. .. The intermediate steering shaft 47 is rotatably supported by the first rolling bearing 51 and the second rolling bearing 53 arranged on both sides of the worm wheel 55 in the axial direction.

The torsion bar 67 is arranged so as to penetrate the center of the steering shaft 17 and the intermediate steering shaft 47, and the left end portion in the drawing is integrally fixed with the intermediate steering shaft 47 by a connecting pin 69, and further, the right end portion in the drawing. Is press-fitted and fixed to the steering shaft 17.
Therefore, the rotational force (steering torque) of the steering shaft 17 is transmitted to the intermediate steering shaft 47 via the torsion bar 67.

As shown in FIG. 2, the worm shaft 57 that meshes with the worm wheel 55 is rotatably supported by the third rolling bearing 75 and the fourth rolling bearing 77 held by the gear housing 73. The end portion of the worm shaft 57 on the base end side is connected to the rotating shaft 61 of the electric motor 11 via a spline joint 63.

<Gearbox>
Next, the above-mentioned gear box 33 will be described in detail.
As shown in FIG. 3, the gearbox 33 includes a plurality of gearbox components including a gearbox main body 35 and a gearbox cover 37. Each of the gear box main body 35 and the gear box cover 37 is a member in which long fiber fibrous fillers (reinforcing fibers) are mainly dispersed and arranged in a resin material. The reinforcing fiber is contained in the resin material in the range of 10 to 60% by weight depending on the intended use. As a result, the impact resistance, creep property, rigidity, and dimensional stability are improved as compared with the case where the gear box 33 is molded by the resin material alone.

In the illustrated example, the gear box 33 is composed of two parts, a gear box main body 35 and a gear box cover 37, but the present invention is not limited to this, and other parts may be further combined. In that case, the other component may be a resin material containing the above-mentioned long fiber fibrous filler.

The gear box 33 is configured by fastening a resin gear box body 35 containing reinforcing fibers and a gear box cover 37 with bolts 39. The fastening portion between the gearbox body 35 and the gearbox cover 37 with bolts 39 is formed by insert-molding a metal core metal on the gearbox body 35 side and a metal core metal on the gearbox cover 37 side. May be good. The gear box 33 having this configuration is lighter than the conventional metal product and has the same durability and reliability as the conventional product.

Although not shown, an O-ring groove on which an O-ring is mounted is provided on the surface to be fastened with bolts, that is, the joint surface between the gearbox body 35 and the gearbox cover 37, and is enclosed in the gearbox 33. It is preferable to prevent leakage of the grease.

The gearbox main body 35 and the gearbox cover 37 (hereinafter, also referred to as gearbox components) having the above configuration will be described in detail later, but are generally manufactured as follows.
First, reinforcing fibers having an average fiber length of 0.5 mm or more are opened in a solvent. A fiber-containing slurry containing the reinforcing fibers is filled in a mold and paper-made to form a preform. The formed preform is set in a molding mold, and a liquid or powder thermosetting resin is injected into the molding mold to impregnate the preform with a resin material. As a result, a gearbox component based on the fiber reinforced resin composition can be obtained.

The gearbox component is preferably manufactured by producing a preform by the above-mentioned three-dimensional papermaking technique, but the present invention is not limited to this. For example, a fiber-containing slurry containing reinforcing fibers having an average fiber length of 0.5 mm or more is inserted into a mold together with a liquid or powder thermosetting resin, and the reinforcing fibers and the resin material are integrated by heating. Gearbox components may be manufactured. This also provides a gearbox component of the fiber-reinforced resin composition in which the reinforcing fibers are dispersed in the resin material, as in the case of papermaking. In any case, the blending amount of the reinforcing fibers contained in the fiber-reinforced resin composition is preferably 10 to 60% by weight.

As the constituent material of the gearbox component, for example, a material in which a thermosetting resin such as an epoxy resin or a phenol resin is mixed as a resin material and a reinforcing fiber such as a glass fiber or a carbon fiber is blended as a fibrous filler is preferable. Further, a part of the thermosetting resin may be replaced with a thermoplastic resin. By using a thermosetting resin as a constituent material, a configuration having excellent heat resistance and mechanical strength can be obtained.
Further, in consideration of durability and reliability as a molded product, it is desirable to use a fiber-reinforced resin composition in which a thermosetting resin is used as a base resin and the base resin is filled with reinforcing fibers. By using this fiber reinforced resin composition, the impact resistance performance of the gearbox components can be ensured as necessary and sufficient.

The reinforcing fiber is not particularly limited, and examples thereof include glass fiber, carbon fiber, metal fiber, aramid fiber, aromatic polyimide fiber, liquid crystal polyester fiber, silicon carbide fiber, alumina fiber, boron fiber, cellulose, cellulose nanofiber and the like. ..

In particular, glass fiber and boron fiber are preferable because of their high tensile strength. Carbon fiber is excellent in wear resistance, heat resistance, thermal elasticity, acid resistance, and electrical conductivity. As the metal fiber, a metal thread such as stainless steel, aluminum, iron, nickel, or copper can be used. Aramid fiber has strong tensile strength and frictional resistance, and is also excellent in high temperature and chemical resistance. Aromatic polyamide fibers have very good heat resistance and strength. Liquid crystal polyester fibers have higher rigidity than engineering plastics reinforced with fillers even in the non-reinforced state. Alumina fiber can be used even in a high temperature range and has fire resistance.

Further, the fiber length of the reinforcing fiber is preferably 0.5 mm or more, more preferably 1 mm or more, with an average fiber length of 0.5 mm or more. When a fiber having an average fiber length of less than 0.5 mm is added, the effect of improving impact resistance and dimensional stability is less than that when a fiber having an average fiber length of 0.5 mm or more is added. By setting the average fiber length to 0.5 mm or more, the reinforcing effect of the resin material in the composite material can be surely obtained.

The blending amount of the reinforcing fibers in the fiber-reinforced resin composition is preferably 10 to 60% by weight. When the blending amount of the reinforcing fiber in the fiber-reinforced resin composition is less than 10% by weight, the durability equivalent to that of the conventional product cannot be obtained. Further, when the blending amount of the reinforcing fibers exceeds 60% by weight, the toughness of the material is impaired, and for example, the cold and thermal impact resistance may be insufficient, which is not preferable.

In the fiber-reinforced resin composition, the affinity between the resin material and the reinforcing fiber can be improved by treating the reinforcing fiber with a coupling agent such as a silane-based coupling agent or a titanate-based coupling agent. Thereby, the adhesion and dispersibility between the resin material and the reinforcing fiber can be improved. The coupling agent is not limited to the silane-based coupling agent and the titanate-based coupling agent.

Then, various additives may be added to the fiber-reinforced resin composition as long as the object of the present invention is not impaired. Examples of the additive include solid lubricants such as graphite, hexagonal boron nitride, fluorine mica, tetrafluoroethylene resin powder, tungsten disulfide, and molybdenum disulfide, inorganic powder, organic powder, lubricating oil, and plasticizer. Rubber, antioxidants, heat stabilizers, UV absorbers, light protectants, flame retardants, antistatic agents, mold release agents, fluidity improvers, thermal conductivity improvers, non-adhesive imparts, crystallization promotion Examples thereof include agents, nucleating agents, pigments, dye agents and the like.

When a gearbox component is manufactured by mixing these resin materials, reinforcing fibers, and various additives, the preform of the reinforcing fibers is impregnated with a molten resin to which various additives other than the reinforcing fibers are added. After that, it is heat-cured. The temperature at which the molten resin is impregnated is not particularly limited, but it may be appropriately selected within a temperature range in which the resin as the base material is sufficiently melted and does not deteriorate.

<Manufacturing of gearbox components>
Next, a method of manufacturing the gearbox component will be described in more detail. Here, the manufacture of the gearbox cover 37 will be described as an example. The production of the gearbox main body 35 is the same as that of the gearbox cover 37, and thus the description thereof will be omitted.

(Gear box cover)
FIG. 4A is a perspective view showing a schematic configuration of the gearbox cover 37, and FIG. 4B is a perspective view showing a schematic configuration of the back side of the gearbox cover 37 shown in FIG. 4A.
The gear box cover 37 is a substantially disk-shaped member having a bearing hole 81 for holding the second rolling bearing 53 in the center. A pair of protrusions 85 having bolt holes 83 are provided along the radial direction on the outer side of the bearing hole 81 in the radial direction. The bolt 39 shown in FIG. 3 is inserted into the bolt hole 83.

Further, in the gearbox cover 37, plate-shaped ribs 87 are arranged in a radial orthogonal direction (downward in FIG. 4A, FIG. 4B) on one side in a direction orthogonal to the line connecting the pair of protrusions 85. ) Protruding upward). Further, on the other side, a pair of bosses 91 having bolt holes 89 are provided so as to project in the same direction as the ribs 87.

(Gear box cover fabrication mold)
FIG. 5 is a schematic perspective view of a papermaking mold for making a preform of the gearbox cover 37, and FIG. 6 is a sectional view taken along line VI-VI of the lower mold 113 shown in FIG.

As shown in FIGS. 5 and 6, the drafting mold 111 has a lower mold 113 and an upper mold 135. The lower mold 113 is provided with a bowl-shaped recess 115 into which a fiber-containing slurry, which will be described later, is injected, and a protruding surface forming portion 117, a protruding portion forming portion 119, a rib forming portion 121, and a boss forming portion 123. The protruding surface forming portion 117 forms one surface of the gearbox cover 37, that is, the surface on the side where the rib 87 and the pair of bosses 91 project. Further, the protrusion forming portion 119 forms the protrusion 85, the rib forming portion 121 forms the rib 87, and the boss forming portion 123 forms a pair of bosses 91. The protruding surface forming portion 117 is a main recess that forms a main surface that serves as a base of the gearbox cover 37, and the bearing hole forming portion 118 projects in the center to form a bearing hole. The protrusion forming portion 119, the rib forming portion 121, and the boss forming portion 123 branch from a part of the main recess to form a branch recess for forming each protruding portion.

In addition, for the sake of simplification of the description, the auxiliary mechanism of the type such as the core and the slide core forming the bolt holes 83 and 89 of the gearbox cover 37 will be omitted here.

Below the rib forming portion 121 and the boss forming portion 123, drainage holes 125 and 127 for discharging the solvent of the fiber-containing slurry injected into the bowl-shaped recess 115 are provided. The drainage hole 125 communicates the rib forming portion 121 with the outside of the lower mold 113, and the drainage hole 127 communicates the boss forming portion 123 with the outside of the lower mold 113.

The reinforcing fibers and the solvent contained in the fiber-containing slurry are between the lower tip of the rib forming portion 121 and the drain hole 125 and between the lower tip of the boss forming portion 123 and the drain hole 127, respectively. The mesh-shaped filter portions 129 and 131 (see FIG. 6) are provided to separate the two. The filter units 129 and 131 allow only the solvent to pass through while blocking the outflow of the reinforcing fibers from the fiber-containing slurry.

Further, the upper mold 135 is formed to have a convex portion 136 corresponding to the bowl-shaped concave portion 115 of the lower mold 113. The convex portion 136 has a mesh-shaped filter portion 133 at its convex tip. The filter unit 133 may have a mesh size that prevents the outflow of reinforcing fibers and allows only the solvent to pass through.

These filter units 129, 131, and 133 may be configured via a porous filter. Examples of the porous filter include a porous body such as sponge and zeolite, a non-woven fabric, and a fibrous mass such as cotton. Further, the filter portions 129, 131, and 133 may be in the form in which a mesh (fine) portion is formed in the mold itself, and further, a porous filter such as a sponge is loaded in the gap between the meshes. You may.

(Gear box cover manufacturing process)
Next, the manufacturing process of the gear box cover 37 will be described.
The manufacturing process of the gearbox cover 37 includes a fiber opening process of reinforcing fibers, a manufacturing process of making a preform 37A of the gearbox cover 37, and an impregnating the prepared preform 37A with a resin material and insert molding the core material. The molding steps to be performed are provided in this order.

7 (A) and 7 (B) are process explanatory views showing how a fiber-containing slurry is produced in the fiber-spreading step.
In the fiber opening step, as shown in FIG. 7A, a large number of pillars 141 containing carbon fibers as reinforcing fibers are put into a container 145 containing the solvent 143 to drive the stirrer 147. As a result, as shown in FIG. 7B, the carbon fibers contained in the pillet 141 are opened in the solvent 143 to obtain a homogeneous fiber-containing slurry 149. The solvent 143 is preferably water (white water) from the viewpoint of stability, handleability, and cost, but may be a solvent such as ethanol or methanol, or a mixture thereof.

The average fiber length of the fibrous filler to be charged is preferably 1 mm or more. As a result, a part of the carbon fibers is broken during opening and shortened, and the average fiber length after opening can be 0.5 mm or more.

8 (A) to 8 (E) are process explanatory views for stepwise explaining the papermaking process.
In the papermaking process, first, the fiber-containing slurry 149 is injected into the lower mold 113 of the papermaking mold shown in FIG. 8 (A) through the nozzle 151. Then, as shown in FIGS. 8B and 8C, the upper die 135 is moved toward the lower die 113 (arrow P). As a result, only the solvent 143 in the fiber-containing slurry 149 passes through the mesh-shaped filter portion 133 by pressing the upper mold 135 and is discharged to the outside of the cavity of the manufacturing mold. Similarly, the solvent 143 of the fiber-containing slurry 149 is discharged from the drain holes 125 and 127 to the outside of the cavity of the fabrication mold via the filter portions 129 and 131.

FIG. 9 is an explanatory view showing the flow direction of the fiber-containing slurry 149 flowing into the boss forming portion.
The reinforcing fibers in the fiber-containing slurry 149 at the time of solvent discharge are aligned in the fiber longitudinal direction in parallel with the flow direction by the flow of the fiber-containing slurry 149. That is, when the fiber-containing slurry 149 flows into the boss forming portion 123, as shown by an arrow F in the figure, the fiber-containing slurry 149 wraps around the edge portion 113a of the lower mold 113 in an arc shape, and the filter at the bottom of the boss forming portion 123 Head to section 131. That is, in the fiber-containing slurry 149 having the present configuration, the fiber longitudinal direction is aligned with the flow direction by the flow due to the solvent discharge. As a result, the thickness of the boss forming portion 123 can be made uniform with high accuracy without causing anisotropy of the coefficient of thermal expansion.

Then, by further moving and pressurizing the upper mold 135 shown in FIG. 8 (C) toward the lower mold 113, as shown in FIG. 8 (D), a preform (fiber lamination) having substantially the same shape as the gear box cover 37 is formed. Body) 37A is made.

Next, as shown in FIG. 8 (E), the wet preform 37A is taken out from the lower mold 113, and the preform 37A is dried.

In the molding step, the dried preform 37A is placed in a known molding mold (not shown). At this time, the cover-side core metal 43 (see FIG. 3), which is a connecting member, may be attached to the preform 37A. Then, the thermosetting resin is injected into the molding mold to impregnate the preform 37A for molding.

Here, it is preferable to preheat the molding die before injecting the thermosetting resin into the molding die. As a result, the thermosetting resin is uniformly heated, molding defects are less likely to occur, the curing time is shortened, and productivity is improved. Further, it is preferable that the cover side core metal 43 is adhered to the preform 37A with an adhesive. In that case, in combination with the strength of the adhesive, the bonding strength of the cover side core metal 43 with the resin material is improved, and the misalignment during molding is less likely to occur.

FIG. 10 is a partially enlarged view schematically showing the boss 91 of the gearbox cover 37 formed by the above-mentioned manufacturing method. In the boss 91 of the gearbox cover 37, the reinforcing fibers 155 are arranged along the outer surface of the boss 91 in the fiber longitudinal direction. That is, at the root portion 157 where the boss 91 stands up, the reinforcing fibers 155 are arranged along the arc direction of the bending of the outer surface of the boss. Further, the reinforcing fibers 155 are arranged in parallel with the outer surface over the entire boss 91.

Therefore, even if a tensile force or a bending moment acts on the boss 91, the direction in which the maximum stress is generated in the boss 91 and the fiber direction substantially coincide with each other, so that the reinforcing effect of the reinforcing fibers 155 is enhanced. As a result, the strength (difficulty of tearing) of the boss 91 is improved as compared with the case where the reinforcing fibers 155 are arranged in the direction perpendicular to the arc direction of the bending. This reinforcing effect is obtained not only for the boss 91 but also for other parts such as the rib 87 (see FIG. 4B). Similarly, the filter portion 133 of the upper die 135 also contributes to aligning the fiber directions of the portion of the gearbox cover 37 on which a particularly high stress acts, in a desired direction.

In the above example, the filter portions 129 and 131 are provided corresponding to the rib 87 and the boss 91, but the present invention is not limited to this. For example, it may be provided in another portion such as a protrusion 85 (see FIGS. 4A and 4B). Further, the filter portion is arranged at the lower tip portion of the rib 87 and the boss 91, but the present invention is not limited to this. For example, the boss 91 may be provided at an arbitrary position such as the axial end surface of the bolt hole 89 of the boss 91 shown in FIG. 10 and the arcuate outer surface of the boss 91.

Generally, in the injection molding method, when reinforcing fibers are mixed in the resin, the fluidity of the resin pellets is small, so that the fluidity of the resin in the mold is lowered. If it is forcibly molded in that state, the reinforcing fibers will be excessively cut, and the shapeability of the gearbox will be reduced. Further, when the resin is melt-mixed with a stirrer (screw) and when the injection-molded material passes through the mold gate, the reinforcing fibers are cut by shearing. For this reason, in a gearbox manufactured by an injection molding method, deterioration of its mechanical properties is unavoidable.
However, in the case of this configuration, since the preform in which the reinforcing fibers are arranged is formed by papermaking and then the preform is impregnated with the resin material, the above-mentioned shearing of the reinforcing fibers does not occur, and the mechanical properties are The drop can be avoided. Further, since the gearbox having this configuration is partially formed with a curved surface to accommodate the gears, the resin material has less stagnation and good resin fluidity can be obtained.

As described above, the present invention is not limited to the above-described embodiment, and can be modified or applied by those skilled in the art based on the combination of the configurations of the embodiments with each other, the description of the specification, and the well-known technique. This is also the subject of the present invention and is included in the scope for which protection is sought.

The gearbox of the present invention is a gearbox applied to various transport machines such as automobiles, motorcycles, railroad vehicles, aircrafts, and ships that are required to be lightweight, in addition to the gearbox provided in the electric power steering device described above. Further, it may be a gear box applied to building equipment such as an elevator or various manufacturing devices.

As described above, the following matters are disclosed in this specification.
(1) A gearbox component that constitutes a gearbox in which a gear mechanism is housed.
A gearbox component formed of a fiber-reinforced resin composition in which a fibrous filler having an average fiber length of 0.5 mm or more is dispersed in a resin material.
According to this gearbox component, it is possible to have a structure having high dimensional accuracy and weight reduction as compared with a conventional metal gearbox component, and also having excellent impact resistance, creep characteristics, and rigidity.

(2) The gearbox component according to (1), wherein the resin material is a thermosetting resin.
According to this gearbox component, by using a thermosetting resin such as an epoxy resin or a phenol resin, a configuration having excellent heat resistance and mechanical strength can be obtained.

(3) The gearbox component according to (1), wherein the amount of the fibrous filler in the fiber-reinforced resin composition is 10 to 60% by weight.
According to this gearbox component, by blending an appropriate amount of the fiber filler, durability equivalent to that of the conventional product can be obtained, and the toughness of the material can be maintained.

(4) The fibrous filler is at least one of glass fiber, carbon fiber, metal fiber, aramid fiber, aromatic polyamide fiber, liquid crystal polyester fiber, silicon carbide fiber, alumina fiber, boron fiber, cellulose and cellulose nanofiber. The gearbox component according to (3), which is selected from one type.
According to this gearbox component, the strength of the fiber-reinforced resin composition can be improved due to the high fiber strength.

(5) The fibrous filler in the fiber-reinforced resin composition is a gearbox component according to any one of (1) to (4), which is arranged so that the fiber longitudinal directions are aligned.
According to this gearbox component, the fiber longitudinal direction of the fibrous filler tends to be in the direction along the stress generation direction, and the mechanical strength is improved.

(6) A metal connecting member is embedded in at least a part of the gearbox component according to any one of (1) to (5).
A gearbox in which a plurality of the gearbox components are connected to each other by fastening members.
According to this gearbox, since the gearbox components are connected to each other by the metal connecting members, the connecting strength can be improved.

(7) There is a method for manufacturing gearbox components that make up a gearbox that houses a gear mechanism.
A fiber-spreading process in which a fibrous filler is opened in a solvent to obtain a fiber-containing slurry.
A papermaking process in which the fiber-containing slurry is injected into a papermaking mold, the solvent is removed from the papermaking mold, and a preform having substantially the same shape as the gearbox component is formed.
A molding step of loading the preform into a molding die, impregnating the preform with a resin material, and molding the gearbox component.
A method of manufacturing a gearbox component having.
According to the manufacturing method of this gearbox component, a gear having a high dimensional accuracy and weight reduction as compared with a conventional metal gearbox component, and having excellent impact resistance, creep characteristics, and rigidity. Can manufacture box components.

(8) The molding step is a step of arranging a metal connecting member in the cavity of the molding mold and insert molding the preform and the connecting member with the resin material. How to manufacture gearbox components.
According to this method of manufacturing the gearbox component, the connecting member can be easily insert-molded.

(9) The gearbox component has a mother body and a protrusion provided so as to project from a part of the mother body to the outside of the mother body.
The papermaking mold has a main recess forming the base body and a branch recess that branches from the main recess to form the protrusion.
The gear box according to (7) or (8), wherein only the solvent in the fiber-containing slurry injected into the branch recess is discharged from the discharge path connected to the branch recess to the outside of the molding mold. Manufacturing method of components.
According to this method of manufacturing the gearbox component, the fiber-containing slurry flows into the branch recess and the solvent is discharged from the discharge path. As a result, the fiber longitudinal direction of the fibrous filler can be arranged in the direction toward the discharge path, and it is possible to intentionally make a papermaking in the fiber direction in which mechanical strength can be easily obtained.

(10) The discharge route is
A filter unit that is arranged facing the tip of the branch recess and separates the fibrous filler and the solvent.
A drainage hole for discharging the solvent separated by the filter unit to the outside of the mold,
The method for manufacturing a gearbox component according to (9).
According to this method for manufacturing the gearbox component, the filter unit can reliably separate the fibrous filler and the solvent from the fiber-containing slurry, leaving only the fibrous filler and discharging only the solvent.

11 Electric motor 13 Reduction gear mechanism 15 Steering mechanism 33 Gearbox 35 Gearbox body (gearbox components)
37 Gearbox cover (gearbox components)
37A Preform 39 Bolt (Fastening Member)
43 Cover side core metal (connecting member)
100 Electric power steering device 111 Extraction mold 113 Lower mold 117 Protruding surface forming part (main recess)
118 Bearing hole forming part 121 Rib forming part (branch recess)
123 Boss forming part (branch recess)
125,127 Drainage hole (drainage route)
129, 131, 133 Filter section (excretion path)
141 Pillet (fibrous filler)
143 Solvent 149 Fiber-containing slurry 155 Reinforcing fiber (fibrous filler)

Claims (8)

A gearbox component that constitutes a gearbox that houses a gear mechanism.
A fibrous filler having an average fiber length of 0.5 mm or more is formed of a fiber-reinforced resin composition in which a fibrous filler is dispersed in the resin material .
It has a mother body and a protruding portion provided so as to project from a part of the mother body to the outside of the mother body.
The fibrous filler in the fiber-reinforced resin composition contained in the protruding portion is arranged so that the fiber longitudinal direction is aligned along the arc direction of bending on the outer surface of the protruding portion.
Gearbox components. The gearbox component according to claim 1, wherein the resin material is a thermosetting resin. The gearbox component according to claim 1 or 2, wherein the amount of the fibrous filler in the fiber-reinforced resin composition is 10 to 60% by weight. The fibrous filler is from at least one of glass fiber, carbon fiber, metal fiber, aramid fiber, aromatic polyamide fiber, liquid crystal polyester fiber, silicon carbide fiber, alumina fiber, boron fiber, cellulose, and cellulose nanofiber. The gearbox component according to claim 3, which is selected. A metal connecting member is embedded in at least a part of the gearbox component according to any one of claims 1 to 4.
A gearbox in which a plurality of the gearbox components are connected to each other by fastening members. There is a method of manufacturing gearbox components that make up the gearbox that houses the gear mechanism.
A fiber-spreading process in which a fibrous filler is opened in a solvent to obtain a fiber-containing slurry.
A papermaking process in which the fiber-containing slurry is injected into a papermaking mold, the solvent is removed from the papermaking mold, and a preform having substantially the same shape as the gearbox component is formed.
A molding step of loading the preform into a molding die, impregnating the preform with a resin material, and molding the gearbox component.
Have a,
The gearbox component has a mother body and a protruding portion provided so as to project from a part of the mother body to the outside of the mother body.
The papermaking mold has a main recess forming the base body and a branch recess branching from the main recess to form the protruding portion.
The papermaking process is
From the discharge path connected to the lower tip of the branch recess, only the solvent in the fiber-containing slurry injected into the branch recess is discharged out of the molding mold to be discharged into the fiber-containing slurry. The fiber longitudinal direction of the opened fiber is aligned along the arc direction of bending on the outer surface of the protruding portion.
How to manufacture gearbox components. The gear box according to claim 6 , wherein the molding step is a step of arranging a metal connecting member in the cavity of the molding mold and insert molding the preform and the connecting member with the resin material. Manufacturing method of components. The discharge route is
A filter unit that is arranged facing the tip of the branch recess and separates the fibrous filler and the solvent.
A drainage hole for discharging the solvent separated by the filter unit to the outside of the mold,
The method for manufacturing a gearbox component according to claim 6 or 7.

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