Gear manufacturing equipment

Abstract

The gear manufacturing device of the present invention accurately controls the arrangement or direction of the reinforcing fibers contained in the resin gear. The gear manufacturing device (1) for manufacturing a gear (100) using a resin containing reinforcing fibers having electrical or magnetic properties comprises: a mold (20) filled with molten resin containing reinforcing fibers; and a configuration adjustment mechanism (24) for generating an electric field or a magnetic field to adjust the arrangement of the reinforcing fibers in the molten resin in the mold (20). The magnetic field can be a rotating magnetic field, and the intensity of the electric field or the magnetic field can be adjusted. Furthermore, the configuration adjustment mechanism can input a higher electric field or magnetic field to the top of the gear teeth than to the root of the gear teeth.

Description

[0001] This application claims the benefit of priority based on Japanese Patent Application No. 2021-034252, filed on March 4, 2021. The entire contents of this Japanese patent application are incorporated herein by reference. Technical Field

[0002] The invention relates to a gear manufacturing device. Background Art

[0003] In recent years, gears made of resin have been increasingly used due to the demand for lightweighting.

[0004] For such resin gears, a technique has been proposed to improve strength by mixing reinforcing fibers into a matrix resin and orienting the reinforcing fibers along the tooth surface on the meshing surface of each tooth (see, for example, Patent Document 1).

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-218994

[0006] However, the gear described above controls the placement of reinforcing fibers by controlling the flow of a matrix resin material mixed with reinforcing fibers when filling a cavity formed in a resin molding die. This results in low feasibility and reproducibility. Summary of the Invention

[0007] An object of the present invention is to provide a gear manufacturing apparatus capable of controlling the arrangement of reinforcing fibers in a favorable manner.

[0008] The present invention provides a gear manufacturing device for manufacturing a gear using a resin containing reinforcing fibers having electrical or magnetic properties, the gear manufacturing device comprising:

[0009] A mold filled with molten resin containing the reinforcing fibers; and

[0010] An adjustment mechanism is provided to generate an electric field or a magnetic field to adjust the arrangement of the reinforcing fibers in the molten resin in the mold.

[0011] According to the present invention, the arrangement of reinforcing fibers can be well controlled. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a side view of the gear manufacturing apparatus according to the first embodiment.

[0013] Figure 2 (A) is a perspective view showing the positional relationship between the gear formed in the mold cavity and the configuration adjustment mechanism provided in the mold. Figure 2 Middle (B) is an axial cross-sectional view of the gear in the cavity taken along the central axis.

[0014] Figure 3This is an axial cross-sectional view of a gear taken along the central axis when permanent magnets are arranged on both sides of the gear.

[0015] Figure 4 This is an axial cross-sectional view of the gear taken along the central axis when electromagnets are arranged on both sides of the gear.

[0016] Figure 5 This is a partial side view of the arrangement adjustment mechanism according to the second embodiment as viewed from the axial direction.

[0017] Figure 6 (A) is a partial side view of the configuration adjustment mechanism according to the third embodiment as viewed from the axial direction. Figure 6 Middle (B) is a line graph showing the waveform of the AC current supplied to the four electromagnets by the current supply unit.

[0018] Figure 7 (A) is a perspective view of the configuration adjustment mechanism according to the fourth embodiment. Figure 7 Middle (B) is its axial cross-section.

[0019] Figure 8 It is an axial vertical cross-sectional view of a mold provided with the arrangement adjustment mechanism according to the fifth embodiment.

[0020] Figure 9 It is an axial vertical cross-sectional view of a mold provided with the arrangement adjustment mechanism according to the sixth embodiment.

[0021] In the figure: 1-gear manufacturing device, 11-base, 20-mold, 21, 22-model, 23-cavity, 24~24F-configuration adjustment mechanism, 30-mold clamping device, 31, 32-opposing walls, 33-connecting rod, 34-movable plate, 35-fluid pressure cylinder, 40-injection device, 41-hopper, 42-cylinder body, 43-motor, 100-gear, 110-tooth root, 120-tooth top, 121-meshing surface, 122-tooth bottom surface, 123-tooth top surface, 241, 241B, 242D, 241E-permanent magnet, 241A, 241C-electromagnet, 241F-first electrode, 242F-second electrode, 243F-voltage applying device, C-center axis. DETAILED DESCRIPTION

[0022] [First embodiment]

[0023] Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. In the first embodiment, a gear manufacturing apparatus 1 is illustrated for manufacturing a gear 100 having a resin matrix such as engineering plastics containing reinforcing fibers (hereinafter referred to as reinforcing fibers).

[0024] For example, the resin of the base material of the gear 100 may be engineering plastics (general engineering plastics) or super engineering plastics (special engineering plastics). Examples of engineering plastics (general engineering plastics) include polyamide (PA), polycarbonate (PC), polyacetal (POM), modified polyphenylene ether (m-PPE), and polybutylene terephthalate (PBT). Examples of super engineering plastics (special engineering plastics) include polyetheretherketone (PEEK), polyamideimide (PAI), polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), aromatic polyamide (PPA), liquid crystal polymer (LCP), polysulfone (PSU), polyethersulfone (PES), polyetherimide (PEI), polyarylate (PAR), and thermoplastic polyimide (TPI). However, the present invention is not limited thereto and may be modified as appropriate.

[0025] Furthermore, examples of the reinforcing fibers include glass fibers, aramid fibers, polyethylene fibers, Zylon fibers, boron fibers, carbon fibers, etc. However, the present invention is not limited thereto and may be modified as appropriate. Furthermore, specific materials may be added to the reinforcing fibers.

[0026] As the gear 100 , for example, a case where the tooth tip 120 contains more reinforcing fibers than the tooth root 110 and a case where the fiber direction of the reinforcing fibers is along the meshing surface 121 of the tooth tip 120 is exemplified.

[0027] [Basic structure of gear manufacturing equipment]

[0028] Figure 1 This is a side view of a gear manufacturing apparatus 1. The gear manufacturing apparatus 1 utilizes an injection molding apparatus as its basic structure. The gear manufacturing apparatus 1 includes a gear mold 20, a base 11 that supports the entire apparatus, a mold clamping unit 30 mounted on one end of the base 11 (on the left side in the figure), and an injection unit 40 mounted on the other end of the base 11 (on the right side in the figure).

[0029] The mold clamping device 30 includes: a pair of opposing wall portions 31 and 32 fixed to the base 11; four connecting rods 33 connecting the pair of opposing wall portions 31 and 32; a movable plate 34 slidably supported on each connecting rod 33; and a fluid pressure cylinder 35 for reciprocating the movable plate 34 along each connecting rod 33.

[0030] The mold 20 is composed of a pair of molds 21 and 22. The mold 21 is held by a movable plate 34, and the mold 22 is held by an opposing wall portion 32. Recesses are formed on the opposing surfaces of each mold 21 and 22, and these recesses constitute a cavity 23 for forming the gear 100. Furthermore, the mold 20 is provided with a configuration adjustment mechanism 24 that generates a magnetic field to adjust the configuration of the reinforcing fibers in the molten resin within the mold 20.

[0031] The fluid pressure cylinder 35 of the mold clamping device 30 presses the mold 21 against the mold 22 held by the opposing wall portion 32 via the movable plate 34 and maintains the mold 21 in a press-contact state, thereby filling the molding material of the gear 100 into the cavity 23 at a predetermined pressure.

[0032] The injection device 40 includes: a hopper 41 for supplying molding material, a cylinder 42 for filling the molding material into the mold 20, an unillustrated screw for stirring and delivering the molding material in the cylinder 42, a motor 43 that serves as a driving source for the screw, and an unillustrated heater for melting the molding material in the cylinder 42.

[0033] The hopper 41 supplies, for example, pelletized matrix resin and reinforcing fibers into the cylinder 42. The matrix resin pellets and reinforcing fibers may be fed into the hopper 41 separately, or resin pellets containing reinforcing fibers may be fed into the hopper 41 together.

[0034] In the cylinder 42, the matrix resin is melted by the heater, and the resin and reinforcing fibers are stirred by the screw while being conveyed to the front end side of the cylinder 42. In addition, at this time, the resin is also melted by the shear friction heat generated by the screw.

[0035] The cylinder 42 has a nozzle at its front end portion, and can fill the stirred molten resin and reinforcing fibers into the cavity 23 of the mold 20 .

[0036] [Configuration adjustment mechanism]

[0037] Figure 2 (A) is a perspective view showing the positional relationship between the gear 100 formed in the cavity 23 of the mold 20 and the configuration adjustment mechanism 24 provided in the mold 20. Figure 2 Middle (B) is an axial cross-sectional view of the gear 100 in the cavity 23 , taken along the central axis C.

[0038] The arrangement adjustment mechanism 24 is composed of an annular permanent magnet 241. The permanent magnet 241 is arranged concentrically with the gear 100 in the cavity 23 in the mold 20. Furthermore, as a prerequisite, the mold 20 is formed of a material that allows the magnetic flux of the permanent magnet 241 to pass well.

[0039] The inner diameter of the permanent magnet 241 is substantially the same as the outer diameter of the tooth bottom surface 122 of the gear 100 , and the outer diameter of the permanent magnet 241 is substantially the same as the outer diameter of the tooth top surface 123 of the gear 100 .

[0040] The inner diameter of the permanent magnet 241 only needs to be greater than the outer diameter of the tooth bottom surface 122 and smaller than the outer diameter of the tooth top surface 123 . The outer diameter of the permanent magnet 241 may be greater than the outer diameter of the tooth top surface 123 .

[0041] Furthermore, the permanent magnet 241 is arranged so that the surface facing the gear 100 in the direction along its central axis C (hereinafter referred to as the axial direction) becomes the north pole and the opposite surface becomes the south pole.

[0042] By adopting the above configuration, the magnetic lines of force representing the magnetic field formed by the permanent magnet 241 penetrate the tooth top 120 of the gear 100 in the axial direction at the highest magnetic flux density.

[0043] Furthermore, a yoke having high magnetic permeability may be provided together with the permanent magnet 241 , and the yoke may guide the magnetic lines of force of the permanent magnet 241 in an appropriate direction.

[0044] In contrast, the reinforcing fibers contained in the molten resin of gear 100 are formed from or contain a ferromagnetic material. Therefore, during the process of filling the molten resin containing the reinforcing fibers into cavity 23, the fibers are attracted by the magnetic field. Consequently, the reinforcing fibers can be distributed more in the tooth tops 120 than in the tooth roots 110 of gear 100.

[0045] And, as Figure 3 As shown, permanent magnets 241 may also be disposed on both axial sides of cavity 23. In this case, it is preferred that the permanent magnets 241 be disposed so that their polarities face the same direction. This allows the magnetic lines of force representing the magnetic field formed by the permanent magnets 241 on both sides to axially penetrate the tooth tops 120 of gear 100 at a higher magnetic flux density, thereby more effectively concentrating the reinforcing fibers at the tooth tops 120 of gear 100.

[0046] And, as Figure 4 As shown, the arrangement adjustment mechanism 24 may be configured to include an electromagnet 241A composed of a coil and a current supply portion (not shown) for supplying current to the electromagnet 241A, instead of the permanent magnet 241 .

[0047] The electromagnet 241A may be disposed on one side or both sides of the cavity 23 in the axial direction.

[0048] The electromagnet 241A is annular and concentric with the gear 100 formed in the cavity 23. The inner diameter of the electromagnet 241A is substantially the same as the outer diameter of the tooth top surface 123 of the gear 100, or may be set slightly larger than the outer diameter of the tooth top surface 123 of the gear 100. When the electromagnet 241A is annular, the magnetic lines of force pass through the inner and outer diameters of the electromagnet 241A. Therefore, the outer diameter of the electromagnet 241A is preferably larger than that of the permanent magnet 241.

[0049] Furthermore, if the electromagnet 241A is used, the current flowing to the electromagnet 241A can be adjusted by the current supply unit, thereby adjusting the strength of the magnetic field.

[0050] Furthermore, the reinforcing fibers contained in the molten resin of gear 100 may be formed of or contain a hard magnetic material and be magnetized in a manner that maintains a polarity along the fiber. In this case, the reinforcing fibers can be directed along the magnetic lines of force formed by permanent magnet 241 or electromagnet 241A within cavity 23.

[0051] In the above Figures 2 to 4 In the case of the arrangement of the permanent magnet 241 or the electromagnet 241A shown, the reinforcing fibers in the gear 100 can be oriented along the axial direction.

[0052] Furthermore, when the reinforcing fibers have magnetic polarity, the magnet 241 or the electromagnet 241A may be arranged so that the magnetic force lines are directed in the radial direction of the gear 100 formed in the cavity 23 .

[0053] In this case, for example, radially magnetized annular permanent magnets may be placed radially outside and inside the gear 100 formed in the cavity 23. Alternatively, electromagnets composed of a plurality of coils centered in the radial direction and arranged along a circle concentric with the gear 100 may be placed radially outside and inside the gear 100.

[0054] [Manufacturing of gears by gear manufacturing equipment]

[0055] The operation of manufacturing the gear 100 using the gear manufacturing apparatus 1 having the above-described configuration will be described.

[0056] First, the mold 21 of the die 20 is mounted on the movable plate 34, and the mold 22 is mounted on the opposing wall 32. Then, the fluid pressure cylinder 35 of the mold clamping device 30 is driven to move the movable plate 34 toward the opposing wall 32, thereby pressing the mold 21 against the mold 22. This forms a cavity 23 between the molds 21 and 22, which is sealed from the outside.

[0057] Meanwhile, pellets of the matrix resin and reinforcing fibers, which will form the molding material for gear 100, are placed into the hopper 41 of the injection unit 40. The molding material for gear 100 is then fed from the hopper 41 into the cylinder 42, where it is heated by a heater and stirred by a screw. The pellets are then transformed into molten resin, which, along with the reinforcing fibers, is conveyed by the screw to the front end of the cylinder 42, where it is then filled into the cavity 23 of the mold 20.

[0058] In the mold 20 , the permanent magnets 241 configuring the adjustment mechanism 24 are arranged so that their magnetic lines of force penetrate the tooth tops 120 of the gear 100 in the cavity 23 , so that the magnetic reinforcing fibers move so as to gather at the tooth tops 120 .

[0059] After the cooling time of the gear 100 has elapsed, the mold 22 is separated from the mold 21 by the mold clamping device 30 , and the gear 100 is removed from the cavity 23 , thereby completing the manufacturing.

[0060] Thus, the gear 100 can be manufactured in which the reinforcing fibers are more concentrated at the tooth top 120 than at the tooth root 110 .

[0061] Furthermore, if the reinforcing fibers have magnetic polarity, it is possible to manufacture the gear 100 in which the directions of the fibers are all parallel to the magnetic lines of force.

[0062] [Technical Effects of the First Embodiment]

[0063] As described above, the gear manufacturing apparatus 1 is configured to adjust the arrangement of the reinforcing fibers by generating a magnetic field by the arrangement adjustment mechanism 24 for the molten resin containing the magnetic reinforcing fibers (composed of or containing a ferromagnetic material) in the mold 20 .

[0064] Therefore, the reinforcing fibers in the molten resin can be induced to have a predetermined arrangement in the mold 20 , and the gear 100 having the target reinforcing resin arrangement can be accurately manufactured.

[0065] In the arrangement adjustment mechanism 24 , the example in which the permanent magnets 241 are arranged so that the magnetic field lines penetrate the gear 100 in the direction along the central axis C of the gear 100 is shown, but the present invention is not limited thereto.

[0066] For example, an annular permanent magnet may be disposed radially outward of the gear 100 to induce more reinforcement fibers to gather on the tooth top 120 side.

[0067] Furthermore, an annular permanent magnet may be arranged radially outside and inside the gear 100 so that the magnetic field lines penetrate the gear 100 in the radial direction of the gear 100. In this way, when the reinforcing fibers have polarity, the fiber directions of the reinforcing fibers can all be aligned in the radial direction of the gear 100.

[0068] [Second embodiment]

[0069] refer to Figure 5 In the first embodiment, the arrangement adjustment mechanism 24 is exemplified as forming a magnetic field with magnetic lines of force directed in a fixed direction (axial direction) with respect to the gear 100 in the cavity 23, but the present invention is not limited thereto.

[0070] In the second embodiment, a gear manufacturing apparatus is exemplified in which an adjustment mechanism 24B is arranged to generate a rotating magnetic field in which the direction and position of magnetic lines of force vary, thereby making the fiber direction of the reinforcing fibers of the gear 100 irregular.

[0071] In addition, regarding the gear manufacturing apparatus of the second embodiment, only the configurations that are different from the gear manufacturing apparatus 1 will be described, and the same configurations will be denoted by the same reference numerals and redundant description will be omitted.

[0072] Figure 5 This is a partial side view of the arrangement adjustment mechanism 24B according to the second embodiment as viewed from the axial direction.

[0073] The arrangement adjustment mechanism 24B includes a plurality of permanent magnets 241B arranged on one side in the axial direction close to and facing each tooth tip 120 of the gear 100 in the cavity 23 and a rotation drive unit (not shown) for rotating each permanent magnet 241B.

[0074] Each permanent magnet 241B is magnetized so that a circular facing surface facing the axial end surface of the tooth tip 120 is divided into an S pole and an N pole along the radial direction.

[0075] The rotation drive unit rotates the permanent magnet 241B about an axis that is parallel to the central axis C and passes through the center of the circle.

[0076] Furthermore, the permanent magnet 241B is not limited to a circular shape and may be configured to face a fixed portion of the axial end surface of the tooth tip 120 and to switch between a south pole and a north pole relative to the fixed portion of the axial end surface of the tooth tip 120. For example, the shapes of the facing surfaces of the permanent magnet 241B may differ from each other, or one end and the other end of a rod-shaped permanent magnet may alternately face the gear 100.

[0077] Furthermore, a rotation drive unit may be provided for each permanent magnet 241 B. In this case, the rotation speeds of the permanent magnets 241B may be the same or different.

[0078] Furthermore, the rotation drive unit may use a roller that circumscribes the outer peripheries of all the permanent magnets 241B to rotate all the permanent magnets 241B simultaneously, or may use a gear transmission mechanism.

[0079] In the gear manufacturing apparatus equipped with the arrangement adjustment mechanism 24B, each permanent magnet 241B is driven to rotate with respect to the molten resin containing reinforcing fibers that is filled in the cavity 23 of the mold 20. As a result, the reinforcing fibers within each tooth top 120 of the gear 100, which is adjacent to and facing the permanent magnet 241B, are stirred in the rotating magnetic field, where the direction and position of the magnetic field fluctuate drastically, causing the fiber orientation of the reinforcing fibers to become irregular.

[0080] Thus, the gear 100 having the tooth top portion 120 in which the direction of the reinforcing fibers is irregular can be manufactured.

[0081] Furthermore, the arrangement of the adjustment mechanism 24B illustrates a case where the permanent magnet 241B and the rotation drive unit are provided only on one axial side of the tooth top 120 of the gear 100 . However, the permanent magnet 241B and the rotation drive unit may be provided on both axial sides.

[0082] Furthermore, the arrangement adjustment mechanism 24B and another arrangement adjustment mechanism may be used in combination. For example, a configuration adjustment mechanism that generates a magnetic field that attracts the reinforcing fibers to the tooth top 120 or a portion thereof (e.g., the meshing surface 121) and an arrangement adjustment mechanism 24B that generates a rotating magnetic field on the tooth root 110 side may be provided. This configuration results in the tooth top 120 side being in a state where the reinforcing fibers are concentrated or directed along the meshing surface 121, while the tooth root 110 side being in a state where the directions of the reinforcing fibers are irregular, thereby manufacturing the gear 100.

[0083] [Third embodiment]

[0084] refer to Figure 6 The third embodiment of the present invention is described below. In the third embodiment, a gear manufacturing apparatus is illustrated in which the fiber direction of the reinforcing fibers of the gear 100 is irregularized by an arrangement adjustment mechanism 24C that generates a rotating magnetic field similar to the arrangement adjustment mechanism 24B described above.

[0085] Regarding the gear manufacturing apparatus of the third embodiment, only the configurations that are different from the gear manufacturing apparatus 1 will be described. The same configurations are denoted by the same reference numerals, and redundant descriptions will be omitted.

[0086] Figure 6 Middle (A) is a partial side view of the arrangement adjustment mechanism 24C according to the third embodiment as seen from the axial direction.

[0087] The arrangement adjustment mechanism 24C includes a plurality of electromagnets 241C arranged close to and facing each tooth top 120 of the gear 100 in the cavity 23 on one side in the axial direction, and a current supply unit (not shown) for supplying alternating current to each electromagnet 241C.

[0088] Four electromagnets 241C are positioned adjacent to one tooth tip 120 of the gear 100 within the cavity 23, facing one axial end surface thereof. The four electromagnets 241C are positioned so that the central axes of their coils are parallel to the central axis C of the gear 100. When viewed axially of the gear 100, the four electromagnets 241C are positioned at the vertices of a square. Furthermore, the winding directions of the coils are the same.

[0089] Figure 6 (B) is a line diagram showing the waveform of the AC current that the energizing unit energizes the four electromagnets 241C. Figure 6 In (B), the horizontal axis is time and the vertical axis is current value. Figure 6 In (A), the four electromagnets 241C are marked with numbers "1", "2", "3", and "4" in the counterclockwise direction, corresponding to Figure 6 The numbers marked on the four waveforms in (B) are shown.

[0090] As shown in the figure, the current supply unit supplies AC current to the four electromagnets 241C in the order of "1", "2", "3", and "4" with a delay of one quarter cycle. This forms a rotating magnetic field in which the positions of the strong magnetic lines of force rotate.

[0091] Furthermore, the timing pattern of the AC current energizing the four electromagnets 241C can be modified so that each of the four electromagnets 241C is different. For example, a phase difference can be generated regardless of the order of arrangement, or every two electromagnets can be in a different phase. In this case, while a rotating magnetic field cannot be achieved, the reinforcing fibers can still be stirred to achieve irregularity.

[0092] In the gear manufacturing apparatus including the arrangement adjustment mechanism 24C, the reinforcing fibers in the molten resin filled in the cavity 23 of the mold 20 are stirred at each tooth top 120 by the rotating magnetic field formed by the four electromagnets 241C energized in different phases.

[0093] Thus, the gear 100 can be manufactured in which the reinforcing fibers in each tooth top 120 are irregular.

[0094] In the configuration adjustment mechanism 24C, the four electromagnets 241C are provided on only one axial side of the tooth top 120 of the gear 100, but four electromagnets 241C may be provided on both axial sides.

[0095] Furthermore, similar to the arrangement adjustment mechanism 24B, the arrangement adjustment mechanism 24C and other arrangement adjustment mechanisms may be used in combination.

[0096] [Fourth embodiment]

[0097] refer to Figure 7The fourth embodiment of the present invention will now be described. This fourth embodiment illustrates a gear manufacturing apparatus equipped with a placement adjustment mechanism 24D that applies a higher magnetic field to areas where a high-density placement of reinforcing fibers is desired, compared to areas where a low-density placement of reinforcing fibers is desired. This placement adjustment mechanism 24D illustrates a case where the high-density placement of reinforcing fibers is located at the tooth tip 120 of a gear 100, while the low-density placement of reinforcing fibers is located at the tooth root 110.

[0098] Regarding the gear manufacturing apparatus of the fourth embodiment, only the configurations that are different from the gear manufacturing apparatus 1 will be described. The same configurations are denoted by the same reference numerals, and redundant descriptions will be omitted.

[0099] Figure 7 (A) is a perspective view of the arrangement adjustment mechanism 24D according to the fourth embodiment. Figure 7 Middle (B) is its axial cross-section.

[0100] As shown in the figure, the configuration adjustment mechanism 24D includes the above-mentioned permanent magnet 241 axially facing the tooth top 120 of the gear 100 in the cavity 23 and a permanent magnet 242D located inside the permanent magnet 241 and axially facing the tooth root 110 of the gear 100.

[0101] The permanent magnet 242D is selected to have a magnetic flux density smaller than that of the permanent magnet 241 (smaller magnetic force).

[0102] Similar to permanent magnet 241, permanent magnet 242D is also arranged so that the surface facing gear 100 in the direction of central axis C (hereinafter referred to as the axial direction) forms the north pole, and the surface opposite this forms the south pole. While the orientation of the north and south poles is preferably aligned with that of permanent magnet 241, the orientations of both permanent magnets 241 and 242D may be opposite to these. With this arrangement, the magnetic lines of force representing the magnetic field generated by permanent magnet 242D axially penetrate the tooth root portion 110 of gear 100.

[0103] The arrangement adjustment mechanism 24D having the above-described structure allows the reinforcing fibers to be arranged at a high density at the tooth top 120 in the mold 20 , and to be arranged at a lower density at the tooth base 110 than at the tooth top 120 .

[0104] Thus, the gear manufacturing apparatus can distribute the reinforcing fibers to various parts of the gear 100 with a desired strength, thereby manufacturing a gear suitable for the intended use.

[0105] Furthermore, when the above-described arrangement adjustment mechanism 24D is adopted, the permanent magnets 241 and 242D may be provided on both sides of the gear 100 in the axial direction.

[0106] Furthermore, when the arrangement adjustment mechanism 24D is used, an electromagnet may be used instead of the two permanent magnets 241 and 242D. In this case, the magnetic flux density of the electromagnet replacing the permanent magnet 242D is preferably adjusted by the number of turns of the coil or the magnitude of the current.

[0107] [Fifth embodiment]

[0108] refer to Figure 8 The fifth embodiment of the present invention will now be described. This fifth embodiment illustrates a gear manufacturing apparatus equipped with an arrangement adjustment mechanism 24E for arranging reinforcing fibers in a more localized location so that the fiber direction is along a predetermined surface of a gear 100. This arrangement adjustment mechanism 24E arranges the reinforcing fibers along the meshing surface 121, tooth bottom surface 122, and tooth top surface 123 of the tooth top 120 of the gear 100, or in the vicinity thereof, along each of the surfaces 121 to 123.

[0109] Regarding the gear manufacturing apparatus of the fifth embodiment, only the configurations that are different from the gear manufacturing apparatus 1 will be described. The same configurations are denoted by the same reference numerals, and redundant descriptions will be omitted.

[0110] Figure 8 It is an axial vertical cross-sectional view of a mold 20 provided with a placement adjustment mechanism 24E according to the fifth embodiment.

[0111] like Figure 8 As shown, the arrangement adjustment mechanism 24E includes a permanent magnet 241E facing the meshing surface 121 , the tooth bottom surface 122 , and the tooth top surface 123 of the tooth top 120 over the entire circumference of the radially outer side of the gear 100 in the cavity 23 .

[0112] In addition, although the structure in which the surface of the permanent magnet 241E constitutes the inner surface of the cavity 23 and directly contacts the molding material of the gear 100 is exemplified here, the present invention is not limited to this.

[0113] The permanent magnet 241 may be configured to be shallowly buried in the mold 20 so as not to come into contact with the molding material of the gear 100 .

[0114] The permanent magnet 241E of the adjustment mechanism 24E attracts the reinforcing fibers to the meshing surface 121 , the tooth bottom surface 122 , and the tooth top surface 123 or their vicinities in the cavity 23 , and the fibers are oriented along the surfaces.

[0115] Thus, according to the gear manufacturing apparatus including the arrangement adjustment mechanism 24E, the gear 100 can be in a state where the reinforcing fibers are gathered at the tooth top 120 and the fiber direction of each reinforcing fiber is along the meshing surface 121 , the tooth bottom surface 122 and the tooth top surface 123 .

[0116] When the fiber directions of the reinforcing fibers are arranged so as to extend along only a portion of the meshing surface 121 , tooth bottom surface 122 , and tooth top surface 123 rather than along all of the surfaces, it is preferable to provide a plurality of permanent magnets on the mold 20 so as to face only the portion of the surfaces.

[0117] [Sixth embodiment]

[0118] refer to Figure 9 The sixth embodiment of the present invention will now be described. While the first to fifth embodiments illustrate configurations in which each of the arrangement adjustment mechanisms 24 to 24E generates a magnetic field to control the reinforcing fibers, the sixth embodiment illustrates a gear manufacturing apparatus including an arrangement adjustment mechanism 24F that generates an electric field to control the reinforcing fibers.

[0119] Figure 9 It is an axial vertical cross-sectional view of a mold 20 provided with a placement adjustment mechanism 24F according to the sixth embodiment.

[0120] like Figure 9 As shown, the configuration adjustment mechanism 24F includes: a first electrode 241F, which is opposite to the meshing surface 121, the tooth bottom surface 122 and the tooth top surface 123 of the tooth top 120 in the entire circumference of the radial outer side of the gear 100 in the cavity 23; a second electrode 242F, which is opposite to the inner circumference of the gear 100 in the entire circumference of the radial inner side of the gear 100; and a voltage applying device 243F, which applies voltage between the first electrode 241F and the second electrode 242F to generate a potential difference.

[0121] The first electrode 241F and the second electrode 242F configuring the adjustment mechanism 24F have a structure insulated from the surroundings.

[0122] Alternatively, the first electrode 241F and the second electrode 242F may be shallowly buried in the mold 20 so as not to come into contact with the molding material of the gear 100 .

[0123] In the sixth embodiment, the reinforcing fibers contained in the molten resin of the gear 100 are formed from or contain a charged material that is easily charged (e.g., carbon fibers). Furthermore, such a charged material is a material having a positive or negative charge polarity, but having a polarity opposite to that of the first electrode 241F, which is positioned in the direction intended to attract the reinforcing fibers. For example, when a positive voltage is applied to the first electrode 241F, the reinforcing fibers are formed from or contain a negatively charged material.

[0124] Furthermore, the reinforcing fibers in a charged state may be prepared in advance and fed into the hopper 41 of the injection device 40 , or a charging mechanism for charging the reinforcing fibers may be provided in the injection device 40 .

[0125] For example, the charging mechanism may be a structure in which the reinforcing fibers are charged by corona discharge when the reinforcing fibers are fed into the hopper 41 or a structure in which the reinforcing fibers are charged by frictional charging.

[0126] Furthermore, when the reinforcing fibers are made of or contain a charged material that is easily charged by friction, a structure may be adopted in which the reinforcing fibers are charged by friction during stirring by the screw in the cylinder 42. In this case, the screw functions as a charging mechanism.

[0127] In the gear manufacturing apparatus including the arrangement adjustment mechanism 24F, when a voltage is applied to the electrodes 241F and 242F so that the first electrode 241F becomes the positive electrode, an electric field consisting of electric force lines from the first electrode 241F to the second electrode 242F is formed.

[0128] Then, when the molten resin containing the charged reinforcing fibers is filled into the cavity 23, the reinforcing fibers with negative polarity are attracted to the meshing surface 121, the tooth bottom surface 122, and the tooth top surface 123 or their vicinities, and the fiber direction is in a state along each surface.

[0129] Thus, according to the gear manufacturing apparatus including the arrangement adjustment mechanism 24F, the gear 100 can be made into a state in which the reinforcing fibers are gathered at the tooth top 120 and the fiber direction of each reinforcing fiber is along the meshing surface 121 , the tooth bottom surface 122 and the tooth top surface 123 .

[0130] Furthermore, by appropriately adjusting the voltage applied by the voltage applying device 243F between the first electrode 241F and the second electrode 242F to a lower value, the reinforcing fibers can be arranged to be distributed more at the tooth top 120 than at the tooth root 110 and to not be arranged along the meshing surface 121, the tooth bottom surface 122, and the tooth top surface 123.

[0131] Furthermore, for example, when a structure is adopted in which the reinforcing fibers are charged with positive polarity on one side and negative polarity on the other side in the fiber direction, the fiber directions of the reinforcing fibers can be controlled so as to be along the lines of force of the electric field.

[0132] When the fiber directions of the reinforcing fibers are arranged so as to extend along only a portion of the meshing surface 121 , the tooth bottom surface 122 , and the tooth top surface 123 rather than along all of the surfaces, it is preferred that a plurality of first electrodes 241F facing only the portion of the surfaces be provided in the mold 20 .

[0133] [other]

[0134] As mentioned above, although embodiment of this invention was described, this invention is not limited to each embodiment mentioned above.

[0135] For example, in the first to sixth embodiments, the gear manufacturing apparatus has been described as manufacturing an external gear as the gear 100 . However, the present invention is not limited to an external gear, and internal gears and various other gears can be manufactured.

[0136] Furthermore, the details shown in the above-described embodiments may be appropriately changed without departing from the spirit of the present invention.

Claims

1. A gear manufacturing device for manufacturing a gear using a resin containing reinforcing fibers having electrical or magnetic properties, the gear manufacturing device comprising: A mold filled with molten resin containing the reinforcing fibers; and An adjustment mechanism is provided to generate an electric field or a magnetic field to adjust the arrangement of the reinforcing fibers in the molten resin in the mold, The arrangement adjustment mechanism arranges the reinforcing fibers to be distributed more on the tooth top than on the tooth root by inputting a higher electric field or magnetic field to the tooth top than to the tooth root.

2. The gear manufacturing device according to claim 1, characterized in that: The arrangement adjustment mechanism generates an electric field on the charged reinforcing fibers filled in the mold.

3. The gear manufacturing device according to claim 1 or 2, characterized in that: It also has a charging mechanism for charging the reinforcing fibers.

4. The gear manufacturing device according to claim 1, characterized in that: The arrangement adjustment mechanism generates a magnetic field on the magnetic reinforcing fibers filled in the mold.

5. The gear manufacturing device according to claim 4, characterized in that: The configuration adjustment mechanism generates a rotating magnetic field.

6. The gear manufacturing device according to claim 5, characterized in that: When the fiber direction is set to be irregular, the arrangement adjustment mechanism generates the rotating magnetic field.

7. The gear manufacturing device according to claim 1, characterized in that: The configuration adjustment mechanism can adjust the intensity of the electric field or the magnetic field.

8. The gear manufacturing device according to claim 4, characterized in that: The configuration adjustment mechanism penetrates the tooth top of the gear with the highest magnetic flux density of magnetic lines of force in the magnetic field.

9. The gear manufacturing device according to claim 1, characterized in that: The arrangement adjustment mechanism includes permanent magnets or electrodes facing each of the meshing surface of the tooth top, the tooth root surface, and the tooth top surface on the radially outer side of the gear.

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