gear

Abstract

To provide low Young's modulus gears that are inexpensive, readily available, and easy to recycle. [Solution] The gear 1 comprises a cylindrical tooth portion 12 and a rotating shaft portion 11 that penetrates the hole of the cylindrical tooth portion 12. The tooth portion 12 has a tooth surface portion 21 having teeth and a support portion 22 provided between the tooth surface portion 21 and the rotating shaft portion 11. The support portion 22 is formed of salt, and the tooth surface portion 21 is formed of salt, or a metal fitting member 33 that is filled with salt and fitted with salt.

Description

Technical Field

[0001] This disclosure relates to gears.

Background Art

[0002] In recent years, gears having gears have been used in various devices.

[0003] Patent Document 1 discloses a drive gear including a gear body integrally provided at an inner end of a rotating shaft and a tooth portion press-fitted and fixed to the gear body. Specifically, the gear body is integrally formed of a material such as chromium molybdenum having a high Young's modulus together with the rotating shaft. Further, the tooth portion is formed of a material having a lower Young's modulus than the material of the gear body, and the material having a lower Young's modulus is chromium molybdenum, synthetic resin, cast iron, or an iron-based sintered material.

[0004] Similarly, for the driven gear, it is disclosed that a material having a high Young's modulus is used for the gear body, and the tooth portion is formed of a material having a lower Young's modulus than the Young's modulus of the gear body on the outer peripheral portion of the gear body.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] Generally, in a gear, an axial misalignment between a rotating shaft and a tooth surface causes vibration and noise (NV). Therefore, high dimensional accuracy is required for the gear to prevent axial misalignment. Also generally, since the gear is composed of a material having the same Young's modulus for the rotating shaft and the tooth portion, the rigidity of the support portion constituting the tooth portion is high. Therefore, in such a gear, even when an axial misalignment occurs between the rotating shaft and the tooth portion, it is difficult to absorb NV.

[0007] Furthermore, recycling gears generally requires melting them down, which often makes recycling difficult. Also, when using low Young's modulus materials for gears, resins, cast iron, and sintered materials can be considered, but resins have a high environmental impact, and cast iron and sintered materials are expensive.

[0008] This disclosure provides low Young's modulus gears that are inexpensive, readily available, and easily recyclable. [Means for solving the problem]

[0009] The gear according to this disclosure comprises a cylindrical tooth portion and a rotating shaft portion that penetrates the bore of the cylindrical tooth portion, wherein the tooth portion has a tooth surface portion having teeth and a support portion provided between the tooth surface portion and the rotating shaft portion, the support portion being formed of salt, and the tooth surface portion being formed of the salt, or a metal fitting member filled with the salt and fitted with the salt. This allows the support portion, at least in the tooth area, to be formed from a low Young's modulus salt. [Effects of the Invention]

[0010] This disclosure makes it possible to provide low Young's modulus gears that are inexpensive, readily available, and easily recyclable. [Brief explanation of the drawing]

[0011] [Figure 1] This diagram shows the configuration of the gear according to Embodiment 1. [Figure 2] This figure shows the force applied to the tooth portion and the state of the dense packing of the salt used as a material in the tooth portion and support portion according to Embodiment 1. [Figure 3] This figure shows the grinding of salt using a millstone according to Embodiment 1. [Modes for carrying out the invention]

[0012] Embodiment 1 The gear according to this embodiment will now be described with reference to the drawings. Figure 1 is a diagram showing an example of the configuration of gear 1. Here, Figure 1(a) is a cross-sectional view of the entire gear 1 cut in the direction along the axis of rotation, Figure 1(b) is a top view of gear 1, Figure 1(c) is a simplified cross-sectional view of gear 1 cut in the direction along the axis of rotation, similar to Figure 1(a), and Figure 1(d) is a cross-sectional view showing another example of the configuration of the support portion and tooth surface of gear 1.

[0013] As shown in Figure 1(a), the gear 1 has a rotating shaft portion 11 and a tooth portion 12 wound around the rotating shaft portion 11. In the following description, it will be assumed that the rotating shaft is arranged to extend in the vertical direction, as shown in Figure 1(a).

[0014] As shown in Figures 1(a) to 1(c), the tooth portion 12 is described here as having a cylindrical shape that is thin in the vertical direction. The tooth portion 12 has a tooth surface portion 21 on which teeth are provided on the outer surface, and a support portion 22 provided between the tooth surface portion 21 and the rotating shaft portion 11 to support the tooth surface portion 21.

[0015] In other words, the gear 1 is formed by fixing the rotating shaft portion 11 to the cylindrical tooth portion 12 by passing through a hole provided in the center of the tooth portion 12.

[0016] Here, the gear 1 is assumed to be made of different materials for the rotating shaft portion 11 and the teeth portion 12. As a specific example, carbon steel is used as the material for the rotating shaft portion 11, and sodium chloride (hereinafter referred to as salt) is used as the material for the teeth portion 12. For example, the Young's modulus of carbon steel is 200 GPa, and the Young's modulus of salt is 49 Pa.

[0017] Figure 1(d) also shows an example where the tooth surface portion 21 and the support portion 22 of the tooth portion 12 are made of different materials.

[0018] Specifically, the support portion 22 can be composed of a film 31 and a salt 32 inserted as a core into the film 31.

[0019] On the other hand, for the tooth surface portion 21, a fitting member 33 into which the film 31 can be inserted and having teeth provided on the outside can be used. Typically, this fitting member 33 is made of metal. Here, the fitting member 33 is provided with a hollow portion 33a into which the tip of the film 31 can be inserted from the support portion 22 side.

[0020] When forming the tooth portion 12, with a part of the film 31 inserted into the hollow portion 33a of the fitting member 33, the salt 32 is filled as a core. As a result, the film 31 expands within the fitting member 33. Therefore, the tip of the film 31 is in a state of fitting into the fitting member 33 according to the filling of the salt 32.

[0021] In this way, the tooth surface portion 21 has the salt 32 filled in the film 31, and the tip portion of the film 31 bulges inside the fitting member 33. That is, the tooth surface portion 21 is formed by the fitting member 33 fitted with the salt 32 due to the filling of the salt 32 into the metal fitting member 33. As a result, the tooth surface portion 21 is in an integrated state with the support portion 22.

[0022] At this time, the support portion 22 is in a state formed by the salt 32 filled in the film 31.

[0023] In this way, as the material constituting at least the support portion 22 of the tooth portion 12, a salt having a lower Young's modulus than the material constituting the rotating shaft portion 11 can be used.

[0024] In the gear 1 formed in this way, by using salt for the support portion 22, even when the center of the rotating shaft portion 11 and the tooth portion 12 are in an axis misalignment state where they do not coincide, the support portion 22 of the tooth portion 12 can bend to balance the unbalance. As a result, noise and vibration in the gear 1 are reduced.

[0025] Furthermore, in gear 1, noise and vibration are reduced because salt has a low Young's modulus, which makes it difficult for noise and vibration to be transmitted. In addition, salt is a material that is readily available worldwide and can be easily recycled by crushing it.

[0026] Here, the required strength of the tooth surface portion 21 of gear 1 will be explained with reference to Figure 2(a). Figure 2(a) shows examples of the state in which the teeth of the tooth surface portion 21 are meshed with the teeth of another gear, and the state in which an external force is applied.

[0027] At this time, the required strength of the tooth surface 21, that is, the bending stress at the tooth root,

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[0028] Next, an example of a method for manufacturing the salt 32 used in the tooth surface portion 21 and the support portion 22, or used for fitting with the fitting member 33 used in the support portion 22 and the tooth surface portion 21, will be described.

[0029] In gear 1, it is desirable to perform close packing using sodium chloride powder of multiple particle sizes in order to reduce variations in the strength of the salt used as a material. Therefore, the salt used in gear 1 can be obtained by grinding sodium chloride powder in a millstone and then compacting it into a shape suitable for use in gear 1.

[0030] Here, Figure 2(b) shows a state in which large spheres are packed together with smaller spheres in the gaps between the large spheres when filling spherical conductors. For this close packing, the diameter of the filler in epoxy that is close packed to achieve high thermal conductivity is given by Bruggeman's formula,

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[0031] Next, we will describe the millstone used to grind sodium chloride powder. The millstone grinds the material between the upper and lower millstones, and both are made of superhard material. Grooves are formed in both the upper and lower millstones to efficiently grind the material.

[0032] In this process, the upper and lower millstones are irradiated with concentrated high energy over a short period of time, such as a femtosecond, which vaporizes a portion of the cemented carbide and forms grooves on a submicron scale. For example, the groove depth in the lower millstone can be about 0.5 μm, but the groove depth can be changed according to the desired diameter of the salt after grinding.

[0033] Furthermore, a millstone with more grooves has more processing points, which increases the amount of sodium chloride that can be crushed in one rotation. Therefore, it is desirable to have a large number of grooves in a millstone.

[0034] Figure 3 shows an example of a millstone in which granular material loaded between the upper and lower millstones is being ground.

[0035] First, as shown in Figure 3(a), a millstone can crush an object between the flat parts of the upper and lower millstones.

[0036] Then, as shown in Figure 3(b), the portion of the object that protrudes upward from the groove of the lower millstone is sheared in accordance with the movement of the upper millstone.

[0037] Furthermore, the portion protruding upward from the groove in the lower millstone will be sheared. Therefore, by changing the depth of the groove, the particle size of the material after grinding can be controlled.

[0038] In this way, with regard to the salt used in the support portion 22 of the teeth portion 12 of the gear 1, it is possible to process the salt using a millstone to produce a particle size that results in a closely packed state when it is filled into the support portion 22.

[0039] While the above example of gear 1 is an optimal example of a helical gear, which is difficult to machine using conventional methods, the shape of the gear is not limited to this, and spur gears, helical gears, rack and pinion gears, etc., can also be manufactured in the same way. Furthermore, there are no particular restrictions on the size, number of teeth, or thickness of the gear.

[0040] It should be noted that the present invention is not limited to the embodiments described above, and can be modified as appropriate without departing from the spirit of the invention. In other words, the above description has been omitted and simplified as appropriate for the sake of clarity, and those skilled in the art can easily change, add, and modify each element of the embodiments within the scope of the present invention.

[0041] In the above, salt was described as the optimal material for at least the support portion 22 of gear 1, but it is not limited to this. For example, bromine, carbonic acid, water glass, etc., may be added to the salt to create a more durable material. In addition, surface coating may be applied to only the tooth surfaces or other parts of the gear to prevent tooth chipping.

[0042] Furthermore, while the use of carbon steel for the rotating shaft portion 11 was described as an optimal example to prevent wear on the sliding portion of the high-speed rotating gear 1, this is not the only option. For example, in cases where the transmitted torque is small or the gear rotates at a low speed, the rotating shaft portion 11 may also be formed from salt, similar to the teeth portion 12, as there is less concern about wear. In this case, since the entire gear 1 is made of salt, it can be easily recycled after use by crushing it back into powder and then compacting it again for reuse.

[0043] Furthermore, salt is edible and readily available worldwide from rock salt and seawater, making it easy to source locally, which is often a challenge in overseas production. In addition, topsoil from farmland that has become unsuitable for cultivation due to salt damage caused by low rainfall can also be used, allowing unwanted materials in the local area to be utilized as useful resources.

[0044] Therefore, materials similar to salt can also be used, primarily inorganic materials such as glass, cement, lime, and gypsum. [Explanation of Symbols]

[0045] 1 gear 11 Rotating shaft 12 Teeth 21 Tooth surface 22 Support part 31 film 32 Salt 33 Fitting member 33a Hollow part

Claims

[Claim 1] A cylindrical tooth section, It comprises a rotating shaft portion that penetrates the hole portion of the cylindrical tooth portion, The aforementioned tooth portion is The tooth surface portion having teeth, It has a support portion provided between the tooth surface portion and the rotating shaft portion, The support portion is formed of salt, The tooth surface is formed by the salt, or by a metal fitting member in which the salt is filled and fitted with the salt. gear.

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