Method of manufacturing gear, gear, and deflection meshing type gear device

Abstract

To provide a manufacturing method that enables manufacture of a gear with accuracy high enough to enable application to a gear device while having the advantage of a molded article formed from a fluid material, the gear, and the deflection meshing type gear device having the gear like this.SOLUTION: A method of manufacturing a gear includes: an intermediate product formation step (J1) of forming a gear intermediate product (IN) by solidifying a fluid material; and a tooth formation step (J2) of forming a tooth (23 g) in the gear intermediate product (IN) by cutting machining. The gear (23) has a fluid-solidified part that has an outer surface formed by solidifying the fluid material, and a cutting-machined part, the outer surface of which is cutting-machined. The tooth (23 g) is included in the cutting-machined part.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a method for manufacturing a gear, a gear, and a flexible mesh gear device. [Background technology]

[0002] Patent Document 1 shows a gear made of a resin material containing carbon fibers. The gear in Patent Document 1 has carbon fibers with a length of 100 μm or less, thereby ensuring durability and wear resistance even though it is a small gear. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-155313 A Summary of the Invention [Problem to be solved by the invention]

[0004] Forming gears by solidifying a fluid material (e.g., a resin material) offers various advantages, such as lower costs. However, molded products formed by solidifying a fluid material are prone to dimensional variation due to various factors that occur during molding. If gears formed by solidifying a fluid material are used in a gear device, the precision required for the gear device may not be achieved.

[0005] The present invention aims to provide a gear and a manufacturing method capable of manufacturing a gear with a precision suitable for use in a gear device while retaining the advantages of a molded product formed from a fluid material, and further aims to provide a flexible mesh type gear device having such a gear. [Means for solving the problem]

[0006] The method for manufacturing a gear according to the present invention comprises the steps of: an intermediate forming step of solidifying the fluid material to form a gear intermediate; a tooth forming step of forming teeth on the intermediate gear by cutting; Includes.

[0007] The gear according to the present invention comprises: A gear having a fluid solidified portion having an outer shape formed by solidifying a fluid material, and a machined portion which is machined, The cutting portion includes teeth.

[0008] The flexible mesh gear device according to the present invention comprises: A flexible meshing gear device including a vibration exciter, an external gear that is flexibly deformed by the vibration exciter, and an internal gear that meshes with the external gear, The internal gear has a fluid solidified portion having an outer shape formed by solidifying a fluid material, and a machined portion which is machined, The cutting portion includes teeth. Effect of the Invention

[0009] According to the present invention, it is possible to provide a gear having the advantages of a molded product formed from a fluid material and a precision suitable for use in a gear device. Furthermore, it is possible to provide a flexible mesh type gear device having such a gear. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a flexible mesh gear device according to an embodiment of the present invention. [Diagram 2] 2A and 2B are plan and sectional views taken along line AA, respectively, of a second internal gear according to an embodiment of the present invention. [Diagram 3] 5A to 5C are diagrams illustrating the manufacturing process of the second internal gear, in which (A) shows the injection molding process, (B) shows the gear intermediate body released from the mold, and (C) shows the tooth cutting process. [Figure 4] FIG. 4 is a plan view showing a gear intermediate body. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0012] Fig. 1 is a cross-sectional view showing a flexure mesh gear device 1 according to this embodiment. In the following, the direction along the rotation axis O1 in Fig. 1 is called the "axial direction", the direction perpendicular to the rotation axis O1 is called the "radial direction", and the direction of rotation about the rotation axis O1 is called the "circumferential direction". Furthermore, in the axial direction, the side of the second cover 27 where the reduced rotational motion is output is called the "output side", and the opposite side is called the "anti-output side".

[0013] 1 is a cylindrical flexible mesh gear device in which an external gear 12 is flexibly deformed to transmit rotational motion about a rotation axis O1. The flexible mesh gear device 1 includes a vibration exciter shaft 10, an external gear 12 that is flexibly deformed by the vibration exciter shaft 10, a first internal gear 22 and a second internal gear 23 that mesh with the external gear 12, and a vibration exciter bearing 15. The flexible mesh gear device 1 further includes a casing 24, a first cover 26, a second cover 27, input bearings 31 and 32, and a main bearing 33.

[0014] The vibrator shaft 10 is a hollow shaft and includes a vibrator 10A having an elliptical outer shape in a cross section perpendicular to the rotation axis O1, and shaft portions 10B and 10C provided on both sides of the axial direction of the vibrator 10A and having a circular outer shape in a cross section perpendicular to the rotation axis O1. Note that the elliptical shape is not limited to a geometrically strict ellipse, but includes an approximate ellipse. The vibrator shaft 10 rotates around the rotation axis O1, and the center of the outer shape of the vibrator 10A in a cross section perpendicular to the rotation axis O1 coincides with the rotation axis O1. The vibrator shaft 10 is an input shaft that is connected to a drive source (not shown) such as a motor to input a driving force.

[0015] The external gear 12 is a cylindrical flexible metal member having teeth on its outer periphery.

[0016] The vibrator bearing 15 is disposed between the vibrator 10A and the external gear 12. The vibrator bearing 15 has a plurality of rolling elements (rollers) 15A and a cage 15C that holds the plurality of rolling elements 15A. The plurality of rolling elements 15A roll with the outer peripheral surface of the vibrator 10A and the inner peripheral surface of the external gear 12 as rolling surfaces (also called raceway surfaces). The vibrator bearing 15 may have an inner ring separate from the vibrator 10A, an outer ring separate from the external gear 12, or both.

[0017] Spacer rings 36, 37 are provided on both axial sides of the external gear 12 and the retainer 15C of the vibration exciter bearing 15 as restricting members that come into contact with them and restrict their axial movement.

[0018] The first internal gear 22 and the second internal gear 23 have teeth 22g and 23g on their inner circumferences, respectively. The teeth 22g and 23g are aligned in the axial direction, with one meshing with the teeth of the external gear 12 on one side from the axial center, and the other meshing with the teeth of the external gear 12 on the other side from the axial center.

[0019] The outer periphery of the first internal gear 22 functions as a casing covering the inside of the flexible mesh gear device 1 together with the casing 24. The first internal gear 22 has a protruding portion on the opposite output side for connection to the first cover 26, and a connecting hole 22h3 is provided in which a connecting member (bolt, etc., the same below) 51 for connecting to the first cover 26 is screwed. Furthermore, the first internal gear 22 has a connecting hole 22h1 for connecting to the casing 24 via a connecting member 53 on the outer periphery, and a connecting hole 22h2 for connecting to an external support member by tightening together with the casing 24. Furthermore, the first internal gear 22 has a fitting surface 22e1 that is spigot-fitted with the casing 24, and a fitting surface 22e2 that is spigot-fitted with the first cover 26. The connecting holes 22h1 to 22h3 are formed with female threads when a connecting member is screwed in, and no female threads are required when a connecting member is passed through.

[0020] The second internal gear 23 has a mating surface 23s1 to whose outer periphery the inner ring 33a of the main bearing 33 is fixed, a contact surface 23s2 that determines the axial position of the inner ring 33a, a connecting hole 23h1 for connecting to an external member to be driven, a connecting hole 23h2 for connecting to the second cover 27, and a mating surface 23e that is spigot-fitted with the second cover 27.

[0021] The casing 24 is connected to the first internal gear 22 via a connecting member 53. The casing 24, together with the first internal gear 22, covers the radial outside of a portion where the teeth 22g, 23g of the first internal gear 22 and the second internal gear 23 mesh with the external gear 12. The casing 24 has a fitting surface 24s to which the outer ring 33b of the main bearing 33 is fixed, a connecting hole 24h1 into which the connecting member 53 screws, and a connecting hole 24h2 that communicates with the connecting hole 22h2 of the first internal gear 22.

[0022] The first cover 26 covers the outer periphery on the anti-output side of the vibrator shaft 10. The first cover 26 has a connecting hole 26h1 that communicates with the connecting hole 22h1 of the first internal gear 22, and is connected to the first internal gear 22 via a connecting member 51.

[0023] The second cover 27 covers the outer periphery on the output side of the vibrator shaft 10. The second cover 27 has connecting holes 27h1, 27h2 that communicate with the connecting holes 23h1, 23h2 of the second internal gear 23, respectively. The connecting hole 27h1 is a through hole for fastening the second cover 27 between an external member to be driven and the second internal gear 23. The connecting hole 27h2 is a through hole having a seat surface for the connecting member 52, and the connecting member 52 is passed through and screwed into the connecting hole 23h2 of the second internal gear 23, whereby the second cover 27 is connected to the second internal gear 23 by itself.

[0024] The input bearing 31 is disposed between the shaft portion 10B of the vibrator shaft 10 and the first cover 26. The first cover 26 rotatably supports the vibrator shaft 10 via the input bearing 31. The input bearing 32 is disposed between the shaft portion 10C of the vibrator shaft 10 and the second cover 27. The second cover 27 rotatably supports the vibrator shaft 10 via the input bearing 32.

[0025] The main bearing 33 has an inner ring 33a, an outer ring 33b, and rolling elements 33c, and is disposed between the second internal gear 23 and the casing 24. The casing 24 rotatably supports the second internal gear 23 via the main bearing 33. Although a ball bearing is shown as the main bearing 33 in FIG. 1, any type of bearing may be used, such as a roller bearing, a cross roller bearing, an angular ball bearing, a tapered bearing, or the like. The outer ring 33b of the main bearing 33 may be integral with the casing 24.

[0026] <Materials of each component> The second internal gear 23 is made of a resin material. The resin material may be a resin alone or a resin containing reinforcing fibers, and various resin materials such as PEEK (Poly Ether Ether Ketone) material and POM (Polyacetal or Polyoxymethylene, etc.) may be used. The resin containing reinforcing fibers may be a composite material such as CFRP (Carbon Fiber Reinforced Plastics), a composite material of resin and other materials, or a bake material (paper bake material, cloth bake material, etc.). When the resin material is a resin alone or the contained reinforcing fibers are fibers that are not bound in a cloth-like shape, the resin material can be used for injection molding or compression molding. When the material contained in the resin material is fibers bound in a cloth-like or strip-like shape, the resin material can be used for compression molding.

[0027] The materials of the other members are not particularly limited, but in this embodiment, they are configured as follows. The first internal gear 22, the casing 24, the first cover 26, and the second cover 27 are configured from any of the resin materials listed above. By making these members from resin, the cost and weight of the flexure mesh gear device 1 can be reduced.

[0028] The vibration exciter shaft 10, the external gear 12, and the spacer rings 36, 37 are made of metal materials such as steel. Although not particularly limited, more specifically, the vibration exciter shaft 10 is made of a steel material such as chrome-molybdenum steel. The external gear 12 is made of a steel material such as nickel-chrome-molybdenum steel. The spacer rings 36, 37 are made of a steel material such as high carbon chrome bearing steel.

[0029] <Operation description> When the vibration exciter shaft 10 is rotated by a driving source such as a motor, the motion of the vibration exciter 10A is transmitted to the external gear 12. At this time, the external gear 12 is restricted to a shape that conforms to the outer circumferential surface of the vibration exciter 10A, and is bent into an elliptical shape having a major axis portion and a minor axis portion when viewed from the axial direction. Furthermore, the external gear 12 is meshed with the fixed first internal gear 22 at the major axis portion. Therefore, the external gear 12 does not rotate at the same rotation speed as the vibration exciter 10A, and the vibration exciter 10A rotates relatively inside the external gear 12. Then, with this relative rotation, the external gear 12 is bent and deformed so that the major axis position and the minor axis position move in the circumferential direction. The period of this deformation is proportional to the rotation period of the vibration exciter shaft 10.

[0030] When the external gear 12 flexes and deforms, the position of its major axis moves, and the meshing position between the external gear 12 and the first internal gear 22 changes in the rotational direction. For example, if the number of teeth of the external gear 12 is 100 and the number of teeth of the first internal gear 22 is 102, the meshing teeth of the external gear 12 and the first internal gear 22 shift each time the meshing position moves around once, causing the external gear 12 to rotate (spin on its axis). With the above number of teeth, the rotational motion of the vibration exciter shaft 10 is decelerated at a reduction ratio of 100:2 and transmitted to the external gear 12.

[0031] Meanwhile, since the external gear 12 also meshes with the second internal gear 23, the meshing position between the external gear 12 and the second internal gear 23 also changes in the rotational direction due to the rotation of the vibration exciter shaft 10. If the number of teeth of the second internal gear 23 and the number of teeth of the external gear 12 are the same, the external gear 12 and the second internal gear 23 do not rotate relative to each other, and the rotational motion of the external gear 12 is transmitted to the second internal gear 23 at a reduction ratio of 1:1. As a result, the rotational motion of the vibration exciter shaft 10 is decelerated at a reduction ratio of 100:2 and transmitted to the second internal gear 23 and the second cover 27, and this rotational motion is output to the external member to be driven.

[0032] <Details of the second internal gear> FIG. 2 shows a second internal gear according to an embodiment of the present invention, where (A) is a plan view thereof and (B) is a cross-sectional view taken along line AA.

[0033] As shown in FIG. 2, the second internal gear 23 has a flange portion 23A extending radially beyond the teeth 23g, which are internal teeth. Since the flange portion 23A is an internal tooth, it extends radially outward beyond the teeth 23g, but if it were an external tooth, it would extend radially inward beyond the teeth. The flange portion 23A further has overhanging portions 23Aa and 23Ab that overhang the output side and the anti-output side, respectively, from the position of the teeth 23g in the axial direction. The overhanging portion 23Aa has a plurality of plate-shaped ribs r extending along the axial direction and the radial direction, and a hollow portion p with a gap between adjacent ribs r. The hollow portion p is open on the output side. The overhanging portion 23Aa side of the flange portion 23A is provided with the above-mentioned connection holes 23h1 and 23h2 and fitting surface 23e. The other overhanging portion 23Ab is provided with the above-mentioned contact surface 23s2, and the above-mentioned fitting surface 23s1 is provided on the outer periphery of the flange portion 23A including the overhanging portion 23Ab.

[0034] The second internal gear 23 has a fluid solidified portion whose outer surface is formed by solidifying a molten resin material (i.e., a fluid material), and a machined portion whose outer surface is machined. The outer surface means the surface that comes into contact with air when the second internal gear 23 is viewed alone. Machined processing is a concept that includes polishing. Tool marks (tool traces) of a tool are added to the machined portion. On the other hand, the tool marks do not appear in the fluid solidified portion. The machined portion and the fluid solidified portion can be distinguished by the presence or absence of the tool marks. Furthermore, when the fluid solidified portion is formed by injection molding, one of the portions of the fluid solidified portion includes the shape of a gate portion through which the molten resin material passes when filling the mold.

[0035] The machined portion includes teeth 23g. The method of machining the teeth 23g is not particularly limited, but includes, for example, tooth forming processing using a gear shaper, a skyping cutter, a hob, etc., and may also be grinding processing using a grindstone.

[0036] The fluid solidified portion includes surfaces (sites) other than the above-mentioned machined portion. For example, the fluid solidified portion includes the surface S1 on the opposite side to the output side of the flange portion 23A, the surface S2 on the output side, the inner peripheral surface S3 of the protruding portion 23Aa, the surface inside the hollowed-out portion p, the contact surface 23s2, the outer peripheral surface S4 of the protruding portion 23Ab, the surfaces other than the female thread portions of the connecting holes 23h1 and 23h2, the fitting surface 23s1, the fitting surface 23e, the female thread portions of the connecting holes 23h1 and 23h2, and the like.

[0037] The fluid solidification portion is formed by, for example, injection molding, but may also be formed by compression molding of a fiber-reinforced resin. The outer shape of the fluid solidification portion is formed to conform to the shape of the mold.

[0038] One or more of the mating surface 23s1, mating surface 23e, and the female threads of the connection holes 23h1 and 23h2 may be included in the machined portion instead of the fluid solidified portion. When the mating surface 23s1 or the mating surface 23e is machined, the machined portion includes polishing using a grindstone or the like. By machining the mating surface 23s1 or the mating surface 23e, the dimensional accuracy of the mating structure via this surface is improved.

[0039] The machined portion of the second internal gear 23 has an area ratio of, for example, 50% or less, and preferably 30% or less, to the entire outer surface of the second internal gear 23. More preferably, only the teeth 23g are machined, and the shape of the portion of the gear intermediate (see FIG. 3(B) and gear intermediate IN in FIG. 4) other than the teeth is maintained in the finished gear (second internal gear 23). While the machined portion provides high machining accuracy, it also increases costs by adding a process. By setting the area ratio of the machined portion to the above ratio, it is possible to obtain high machining accuracy in the required portions while maintaining the advantage that the second internal gear 23 can be manufactured at low cost.

[0040] <Details of the first internal gear> The first internal gear 22 has a fluid solidified portion, the outer surface of which is formed by solidifying a molten resin material, and a machined portion, the outer surface of which is machined. In the first internal gear 22, the machined portion includes teeth 22g. The machined portion may include one or more of the female thread of the connecting hole 22h1 and the fitting surfaces 22e1 and 22e2. The fluid solidified portion of the first internal gear 22 corresponds to a portion other than the machined portion. The fluid solidified portion and the machined portion can be distinguished in the same manner as in the method described for the second internal gear 23. In the first internal gear 22, the machined portion of the first internal gear 22 is, for example, 50% or less, and preferably 30% or less, in terms of area ratio to the entire outer surface of the first internal gear 22. Furthermore, it is more preferable that only the teeth 22g are machined, and the shape of the portion other than the teeth of the gear intermediate body is maintained in the finished gear (first internal gear 22).

[0041] <Gear manufacturing method> Fig. 3 is a diagram illustrating the manufacturing process of the second internal gear, in which (A) shows an injection molding step, (B) shows a gear intermediate body released from the mold, and (C) shows a tooth cutting step. Fig. 4 is a plan view showing the gear intermediate body.

[0042] The manufacturing method for a gear in this embodiment includes an intermediate body formation process J1 in which a gear intermediate body IN is formed by solidifying a molten resin material, which is a fluid material, as shown in Figures 3(A) and (B), and a tooth formation process J2 in which teeth 23g are formed in the gear intermediate body IN by cutting, as shown in Figure 3(C).

[0043] As shown in Fig. 3(A), the intermediate forming process J1 is an injection molding process in which molten resin material is fed from an injection nozzle N1 into a cavity of a mold E1 and solidified within the mold E1. The mold E1 is opened and the molded product is released, thereby obtaining a gear intermediate IN having a shape that fits the cavity of the mold E1. The intermediate forming process J1 may be a compression molding process. In this embodiment, the resin material (e.g., PEEK material) contains reinforcing fibers (e.g., carbon fibers), and the material of the gear intermediate IN may be a fiber-reinforced resin.

[0044] As shown in Fig. 3(B) and Fig. 4, the gear intermediate IN has a thick portion M1 at a portion that will become the tooth 23g, which is thicker in the radial direction than the tooth height of the tooth 23g and has no irregularities on its surface (inner peripheral surface). Note that the thick portion M1 may have irregularities corresponding to the bottom and tip of the tooth 23g and may have a shape that is thicker in the radial direction than the tooth 23g. By forming the irregularities in advance, it is possible to suppress stress concentration in the thick portion M1 during molding.

[0045] Furthermore, when the portions other than the teeth 23g, such as the fitting surface 23s1 or the fitting surface 23e, are used as the target of the cutting process, thick portions M2, M3 are formed in these portions of the gear intermediate body IN, the thickness of which is greater by the amount of cutting (polishing). The portions other than the thick portions M1 to M3 have the same shape as the second internal gear 23 in its final form.

[0046] In the tooth forming step J2, as shown in Fig. 3(C), teeth 23g are formed by cutting (the smooth inner peripheral surface of) the thick-walled portion M1 of the gear intermediate IN using a gear shaper C. Note that the tooth forming step J2 may use another tool such as a skyping cutter or a hob, or may include a grinding step using a grindstone.

[0047] The manufacturing method of the gear of this embodiment may further include a cutting step for the portion requiring high dimensional accuracy. For example, in this cutting step, the fitting surface 23s1 or the fitting surface 23e of the intermediate gear IN is cut (polished with a grindstone, etc.). This step is performed before or after the teeth forming step J2, or in parallel with the teeth forming step J2.

[0048] The second internal gear 23 of the flexible mesh gear device 1 of this embodiment is manufactured through the above-mentioned multiple steps. The first internal gear 22 may be manufactured through the same steps as above. Furthermore, the internal gears or external gears included in various gear devices may be manufactured through the same steps as above.

[0049] As described above, the gear manufacturing method of this embodiment includes an intermediate body forming step J1 in which a gear intermediate body IN is formed by solidifying a fluid material, and a teeth forming step J2 in which teeth 23g are formed on the gear intermediate body IN by cutting. In the intermediate body forming step J1, the gear intermediate body IN is formed by solidifying a fluid material, which has the effect of reducing manufacturing costs. On the other hand, even if the dimensional accuracy is reduced in the step of solidifying the fluid material, the teeth 23g can be machined with high accuracy in the teeth forming step J2. Therefore, a gear (second internal gear 23) that can be applied to a high-precision gear device can be manufactured at low manufacturing cost.

[0050] Furthermore, according to the gear manufacturing method of this embodiment, in the intermediate forming step J1, the gear intermediate IN is formed by injection molding. Injection molding makes it possible to form the gear intermediate IN at low cost and with little variation in quality. This improves yield and makes it possible to manufacture a gear (second internal gear 23) that can be used in high-precision gear devices at lower manufacturing costs.

[0051] Furthermore, according to the manufacturing method of the gear of this embodiment, the resin material contains reinforcing fibers. Therefore, it is possible to manufacture a high-strength gear that can be applied to a gear device with a large torque. Here, it is assumed that the shape of the teeth 23g is formed by injection molding using a resin material containing reinforcing fibers. In this case, in order to realize a fine shape of the tooth tip and the tooth bottom, the length of the fibers must be shortened, otherwise the distribution rate of the reinforcing fibers will decrease on the surface of the teeth 22g, and restrictions will be imposed on the length of the fibers. On the other hand, according to the manufacturing method of the gear of this embodiment, the formation of fine teeth 23g is not necessary in the molding process of solidifying the resin material, and the teeth 23g are formed by cutting, so that even if long reinforcing fibers are used, a good fiber distribution can be obtained throughout the teeth 23g. Therefore, it is possible to manufacture a gear with high accuracy and high strength.

[0052] Furthermore, according to the manufacturing method of the gear of this embodiment, the thick portion M1 where the teeth 23g of the gear intermediate IN are formed has a smooth surface. Therefore, when filling the mold E1 with molten resin material, the thick portion M1 can be filled easily. Furthermore, even if the material contains reinforcing fibers, the thick portion M1 can be filled with the resin material with good fiber distribution. Therefore, the teeth 23g with high strength and little variation in quality can be obtained through the subsequent cutting process.

[0053] Furthermore, the second internal gear 23 of the flexible mesh gear device 1 is manufactured according to the gear manufacturing method of this embodiment. The flexible mesh gear device 1 can achieve high-precision operation with little backlash due to the high-precision gears. Therefore, by applying the lightweight, high-precision, and low-cost second internal gear 23 manufactured according to the manufacturing method of this embodiment, a lightweight, high-precision, and low-cost flexible mesh gear device 1 can be realized.

[0054] The second internal gear 23 of this embodiment has a fluid solidified portion whose outer surface is formed by solidifying a resin material, and a machined portion whose outer surface is machined, and the machined portion includes teeth 23g. Therefore, the fluid solidified portion can reduce costs, while realizing a second internal gear 23 having high dimensional accuracy of the teeth 23g. Furthermore, the flexible meshing gear device 1 having the second internal gear 23 can achieve high-precision operation while reducing the weight and cost of the device.

[0055] The above describes the embodiments of the present invention. However, the present invention is not limited to the above embodiments. For example, in the manufacturing method of the gear of the above embodiment, an example was shown in which a fluid material is injection molded to form a gear intermediate IN. However, the intermediate forming step may be any molding method such as compression molding or molding using a 3D printer, as long as the gear intermediate can be formed by solidifying a fluid material (including a case where a powder or granular material is melted to form a fluid). In addition, in the manufacturing method of the gear of the above embodiment, the fitting surface 23s1 to which the inner ring 33a of the main bearing 33 is fixed is shown as the surface to be machined, but if there is a fitting surface to which the outer ring of the bearing is fixed, this surface may be the target of the machined processing. In addition, the entire connecting hole may be the target of the machined processing. Furthermore, in the above embodiment, a resin material is shown as the fluid material constituting the gear, but the gear intermediate may be formed by a molding method such as aluminum die casting, casting, or 3D printing using a molten metal such as molten aluminum or molten iron as the fluid material. Even in this case, the inclusion of a process for solidifying and shaping the fluid material allows the cost of the gear to be reduced, while the cutting process for forming the teeth allows for high precision in the dimensions and shape of the teeth. In the embodiment, an internal gear of a flexible mesh gear device has been described as an example, but the gears that are the subject of the present invention are not particularly limited, and the present invention can also be applied to external gears and orthogonal gears, for example. Other details shown in the embodiment can be modified as appropriate without departing from the spirit of the invention. [Explanation of symbols]

[0056] 1 Flexible mesh gear device 10A vibrator 12 External gear 15 Vibrator bearing 22 First internal gear 22e1, 22e2 mating surface 22g Teeth 22h1~22h3 Connection hole 23 Second internal gear 23A Flange part 23Aa, 23Ab protruding part 23e Mating surface 23g Teeth 23h1, 23h2 connection hole 23s1 Mating surface 23s2 Contact surface 33 Main bearing 33a Inner Circle J1 Intermediate formation process E1 type IN Gear intermediate body r Rib p Hollowed out part J2 Tooth formation process M1~M3 Thick part

Claims

1. an intermediate forming step of solidifying the fluid material to form a gear intermediate; a tooth forming step of forming teeth on the intermediate gear by cutting; A method for manufacturing a gear comprising the steps of:

2. In the intermediate body forming step, a resin material is injection molded to form the gear intermediate body. A method for manufacturing a gear according to claim 1.

3. The resin material includes reinforcing fibers. The method for manufacturing a gear according to claim 2.

4. In the intermediate forming step, a surface without irregularities is formed in a portion where teeth are to be formed, In the tooth forming step, teeth are formed on the surface without irregularities. The method for manufacturing a gear according to any one of claims 1 to 3.

5. The intermediate gear has a shape that is maintained in a finished gear except for the teeth. The method for manufacturing a gear according to any one of claims 1 to 4.

6. Manufacture an internal gear of a flexible mesh gear system; The method for manufacturing a gear according to any one of claims 1 to 5.

7. A gear having a fluid solidified portion having an outer shape formed by solidifying a fluid material, and a machined portion which is machined, A gear in which the machined portion includes teeth.

8. A flexible meshing gear device including a vibration exciter, an external gear that is flexibly deformed by the vibration exciter, and an internal gear that meshes with the external gear, The internal gear has a fluid solidified portion having an outer shape formed by solidifying a fluid material, and a machined portion which is machined, The machined portion includes teeth.

Images