Microminiature sun gear and speed reduction planetary gear system using same

Abstract

The utility model discloses a microminiature sun gear and a speed reduction planetary gear system using the same. The microminiature sun gear comprises a tooth-shaped part and a structure reinforcing part which are integrally machined and formed. The tooth-shaped part comprises a plurality of gear teeth evenly distributed in the circumferential direction and a center hole formed in the axis of the tooth roots of the gear teeth. The structure reinforcing part is arranged at one shaft side end of the tooth-shaped part; the structure reinforcing part is provided with an extending hole which is communicated with the center hole and integrally formed. And at least part of the extension holes are consistent with the central hole in cross section shape and size along the direction vertical to the axial direction of the tooth-shaped part. The microminiature sun gear has the advantages of being small in size and high in strength and can bear larger torque, and therefore the requirements for large torque, long service life and compact structure of a speed reduction planetary gear system can be met.

Description

Technical Field

[0001] The utility model relates to the field of transmission structures, in particular to a micro-miniature sun gear and a planetary gear reduction system using the same. Background Art

[0002] Most of the joint drive modules of automation equipment adopt a planetary gear reduction system driven by a permanent magnet brushless outer rotor motor. In order to achieve large torque output and lightweight, the product has high reliability requirements and a compact volume. Generally, a small-volume design of the planetary gear system is achieved by reducing the outer diameter of the sun gear. After reducing the outer diameter of the sun gear, the distance between the root circle of the sun gear and the assembly inner hole becomes smaller, which easily leads to a reduction in the root strength of the teeth.

[0003] In this regard, the publication number CN220523228U discloses a high-precision small sun gear, which includes a central shaft. One end of the central shaft is the bottom surface, and a connection channel is provided on the bottom surface. An auxiliary connection block is inserted into the connection channel, and the external motor shaft is connected to the auxiliary connection block. Then, the auxiliary connection block is inserted into the connection channel, so that the motor shaft can be connected to the central shaft. This kind of small sun gear needs to design an additional matching auxiliary connection block, so the overall structure assembly is cumbersome, and the increase in components will also increase the assembly difficulty. Especially, the production accuracy requirements of each component are high to ensure that multiple components can be properly matched.

[0004] Another example is that the publication number CN218953960U discloses a small high-torque direct-drive sun gear. A group of convex plates are fixedly arranged on the outer side of the output shaft. The assembly component includes a plurality of groove columns arranged on the left side of the wheel shaft. The positions of the plurality of groove columns correspond to a plurality of card slots. A group of groove bodies are opened on the inner wall of the wheel shaft, and the corresponding groove bodies are engaged with the convex plates, which can facilitate the user to quickly and stably disassemble and assemble the sun gear on the output shaft. This kind of sun gear needs to design convex groove columns at the tooth root. Based on this, as the volume of the sun gear shrinks, the area of the overall tooth root of the sun gear also shrinks synchronously. For the small-area tooth root, it is difficult to simultaneously meet the requirements of the design of the groove columns and ensure that the aperture of the shaft hole meets the use strength requirements.

[0005] Therefore, for the existing micro-miniature sun gear, in terms of the need to balance its use strength and the simplicity of the overall structure, its structure needs to be further optimized and improved. Summary of the Utility Model

[0006] The first object of the utility model is to provide a micro-miniature sun gear to solve the technical problem of balancing its use strength and the simplicity of the overall structure.

[0007] The second object of the present utility model is to provide a planetary gear reduction system to solve the technical problem of taking into account the service strength of the sun gear used and the simplification of the overall structure.

[0008] The micro-miniature sun gear of the present utility model is realized as follows:

[0009] A micro-miniature sun gear, comprising:

[0010] A tooth profile part and a structure strengthening part integrally formed; wherein

[0011] The tooth profile part includes a plurality of teeth evenly distributed along the circumferential direction and a central hole provided at the axis of the tooth roots of the plurality of teeth;

[0012] The structure strengthening part is provided at one axial end of the tooth profile part; the structure strengthening part has an extension hole that penetrates through and is integrally formed with the central hole;

[0013] The cross-sectional shape and size of at least a part of the extension hole along the section perpendicular to the axial direction of the tooth profile part are the same as those of the central hole.

[0014] In an optional embodiment of the present utility model, the cross-sectional shape and size of the entire extension hole along the section perpendicular to the axial direction of the tooth profile part are the same as those of the central hole.

[0015] In an optional embodiment of the present utility model, the structure strengthening part is in the shape of a cylindrical structure; and

[0016] The outer diameter of the structure strengthening part is not less than the outer diameter of the addendum circle of the tooth profile part.

[0017] In an optional embodiment of the present utility model, the axial length of the structure strengthening part is less than the axial length of the tooth profile part.

[0018] In an optional embodiment of the present utility model, the axial length of the structure strengthening part is 1 / 3 to 1 / 2 of the axial length of the tooth profile part.

[0019] In an optional embodiment of the present utility model, the cross-section of the central hole along the section perpendicular to the axial direction of the tooth profile part is a polygon.

[0020] In an optional embodiment of the present utility model, a reduced-diameter hole communicating with the central hole is further formed at the axis of the tooth roots of the plurality of teeth;

[0021] The reduced-diameter hole is located at one end of the central hole away from the structure strengthening part, and the reduced-diameter hole extends to the axial end of the tooth profile part away from the structure strengthening part; and

[0022] The cross-sectional area of the reduced-diameter hole along the section perpendicular to the axial direction of the tooth profile part is smaller than the cross-sectional area of the central hole along the section perpendicular to the axial direction of the tooth profile part.

[0023] In an alternative embodiment of the present utility model, a closed reinforcement portion is further formed at the axis of the tooth roots of multiple said gear teeth;

[0024] The closed reinforcement portion is located at one end of the central hole away from the structural reinforcement portion, and this closed reinforcement portion extends to the axial side end of the tooth profile portion away from the structural reinforcement portion.

[0025] In an alternative embodiment of the present utility model, the axial length of the central hole accounts for 1 / 3 to 2 / 3 of the axial length of the tooth profile portion.

[0026] The reduction planetary gear system of the present utility model is implemented as follows:

[0027] A reduction planetary gear system, comprising: the micro-miniature sun gear.

[0028] Adopting the above technical solution, the present utility model has the following beneficial effects: The micro-miniature sun gear of the present utility model and the reduction planetary gear system using the same, through the structural reinforcement portion integrally formed at one end of the tooth profile portion, this structure improves the load-bearing torque of the sun gear, strengthens the structure at the position where the tooth root of the tooth profile portion is prone to fracture, and greatly reduces the bending stress of the tooth root of the tooth profile portion.

[0029] Furthermore, by designing a reduced-diameter hole or a closed reinforcement portion at one end of the tooth profile portion away from the structural reinforcement portion, the overall strength of the tooth profile portion at the end away from the structural reinforcement portion can be enhanced, thereby preventing the tooth root of this part of the structure of the tooth profile portion from cracking.

[0030] In addition, the micro-miniature sun gear of the present utility model only optimizes the design of its overall structure and does not need to be assembled with other components for use. Therefore, the micro-miniature sun gear of the present utility model has the advantages of simplified assembly process, reduced production and assembly difficulty, small volume, and high strength, can bear a greater torque, and thus can meet the requirements of large torque, long life, and compact structure of the reduction planetary gear system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is a structural schematic diagram of the micro-miniature sun gear of the present utility model;

[0032] Figure 2 is a first perspective sectional structural schematic diagram of the micro-miniature sun gear of the present utility model;

[0033] Figure 3 is a second perspective sectional structural schematic diagram of the micro-miniature sun gear of the present utility model;

[0034] Figure 4 is a structural schematic diagram of the micro-miniature sun gear of the present utility model in a mating state with a power shaft.

[0035] In the figure: tooth-shaped part 1, structural reinforcement part 2, central hole 3, reduced-diameter hole 4, extended hole 5, guiding part K, power shaft 6. Detailed implementation mode

[0036] In order to make the content of the present utility model easier to be clearly understood, the following further details the present utility model according to specific embodiments in conjunction with the accompanying drawings.

[0037] Embodiment 1:

[0038] Please refer to Figures 1 to 4 As shown, this embodiment provides a micro-sized sun gear, including: a tooth-shaped part 1 and a structural reinforcement part 2 integrally processed and formed. From the production process perspective, the micro-sized sun gear of this embodiment can be processed by powder metallurgy technology, which can flexibly change the structural dimensions according to specific design requirements and has a low cost. It can also adopt metal volume forming methods, such as cold heading, hot extrusion deformation, etc., and can have better mechanical strength.

[0039] Specifically, the tooth-shaped part 1 includes a plurality of teeth evenly distributed along the circumferential direction and a central hole 3 provided at the axis center of the tooth roots of the plurality of teeth. The structural reinforcement part 2 is provided at one axial end of the tooth-shaped part 1; the structural reinforcement part 2 has an extended hole 5 that is in communication with and integrally formed with the central hole 3.

[0040] Regarding the extended hole of the structural reinforcement part 2, it should be noted here that at least part of the cross-sectional shape and size of the extended hole 5 along the section perpendicular to the axial direction of the tooth-shaped part 1 are the same as those of the central hole.

[0041] In this regard, in the first optional implementation case, the overall cross-sectional shape of the extended hole 5 along the section perpendicular to the axial direction of the tooth-shaped part 1 is the same as that of the central hole 3. In this way, the same processing die can be used for the forming processes of the extended hole 5 and the central hole 3, so it is easy to process. The accompanying drawings of this embodiment only take this case as an example. For this case, considering improving the smoothness and efficiency of the insertion process of the micro-sized sun gear and the power shaft 6 in the reduction planetary gear system, since the power shaft 6 is first inserted into the extended hole 5 of the structural reinforcement part 2 and then into the central hole 3, and the overall cross-sectional shape and size of the extended hole 5 along the section perpendicular to the axial direction of the tooth-shaped part 1 are the same as those of the central hole 3 and are symmetrical, a chamfer is provided at the end of the extended hole 5 facing away from the central hole 3 to form the guiding part K.

[0042] In the second alternative embodiment, only a part of the extension hole 5 has the same cross-sectional shape and size as the central hole 3 along the section perpendicular to the axial direction of the tooth-shaped portion 1, and this part is connected to the central hole 3. On the side of the extension hole 5 relatively far from the central hole 3, the cross-sectional shape and size along the section perpendicular to the axial direction of the tooth-shaped portion 1 can be different from those of the central hole 3. At this time, it should be noted that this different part needs to satisfy that the dimension along the section perpendicular to the axial direction of the tooth-shaped portion 1 is greater than that of the central hole 3, so as not to affect the insertion of the power shaft 6 due to this different part, that is, the extension hole 5 meets the requirement of the through insertion of the power shaft 6.

[0043] The structural strengthening part 2 here is mainly used to enhance the strength of one axial end of the tooth-shaped portion 1. Therefore, for its overall shape, as long as the outer wall surface is not tooth-shaped but a solid structure, it generally meets the usage requirements of this embodiment. For its cross-sectional shape perpendicular to the axial direction of the tooth-shaped portion 1, it can be circular, regular polygon or even irregular shape, and theoretically it meets the usage requirements.

[0044] Based on the above situation, combined with an example of an alternative embodiment, the structural strengthening part 2 is a cylindrical structure. In this regard, it should be noted that in order to give full play to the strengthening effect of the structural strengthening part 2 on the strength of the overall micro sun gear, the outer diameter of the structural strengthening part 2 is not less than the outer diameter of the addendum circle of the tooth-shaped portion 1. For example, the outer diameter of the structural strengthening part 2 shown in the attached drawing is greater than the outer diameter of the addendum circle of the tooth-shaped portion 1.

[0045] On the basis of the above structure, it is necessary to note that for the overall micro sun gear, when it is actually applied in a reduction planetary gear system, the tooth-shaped portion 1 plays the role of meshing and transmitting with other gears. Therefore, it is necessary to ensure the axial length of the overall tooth-shaped portion 1 to adapt to other gears, and the structural strengthening part 2 is mainly used to enhance the overall strength of the tooth-shaped portion 1. Therefore, the axial length of the structural strengthening part 2 is less than the axial length of the tooth-shaped portion 1. In an alternative embodiment, the axial length of the structural strengthening part 2 is 1 / 3 to 1 / 2 of the axial length of the tooth-shaped portion 1.

[0046] In addition, in order to facilitate the reliable connection between the micro sun gear of this embodiment and the power shaft 6 when it is applied to a specific reduction planetary gear system, and to simplify the assembly process of the power shaft 6 and the micro sun gear of this embodiment, the cross-section of the central hole 3 of this embodiment perpendicular to the axial direction of the tooth-shaped portion 1 is a polygon, such as a square or a regular hexagon, or other polygon structures, that is, as long as it is not circular, it can prevent the unexpected relative rotation problem between the central hole 3 and the power shaft 6. At this time, for the power shaft 6 and the micro sun gear of this embodiment, a reliable rotation-following fit connection relationship can be formed between the two through the clearance fit of the polyhedron. Compared with the situation of using a circular shape and forming an interference fit with the power shaft 6, the assembly difficulty is low, and the production accuracy requirement is also reduced synchronously.

[0047] In summary, during the use of the micro sun gear of this embodiment in cooperation with the power shaft 6, the rear end portion of the overall micro sun gear (here, in terms of the assembly process of the sun gear and the power shaft 6, the power shaft 6 is first inserted into the sun gear from the rear end portion) bears most of the torque transmission of the power input shaft. Therefore, in this embodiment, the structural strengthening portion 2 integrally formed at the rear end portion of the tooth profile portion 1 improves the torque-bearing capacity of the sun gear, strengthens the structure at the position where the tooth root of the tooth profile portion 1 is prone to fracture, and greatly reduces the bending stress of the tooth root of the tooth profile portion 1.

[0048] Embodiment 2:

[0049] Please refer to Figures 1 to 4 As shown, based on the micro sun gear of Embodiment 1, the micro sun gear proposed in this embodiment also makes the following design at one end of the tooth profile portion 1 away from the structural strengthening portion 2:

[0050] In the first optional implementation case, a reduced-diameter hole 4 communicating with the central hole 3 is further formed at the axis center of the tooth roots of multiple teeth; the reduced-diameter hole 4 is located at one end of the central hole 3 away from the structural strengthening portion 2, and the reduced-diameter hole 4 extends to the axial side end of the tooth profile portion 1 away from the structural strengthening portion 2.

[0051] In this regard, it should be noted that the cross-sectional area of the reduced-diameter hole 4 along the axis perpendicular to the tooth profile portion 1 is smaller than the cross-sectional area of the central hole 3 along the axis perpendicular to the tooth profile portion 1. Combining with the drawings to give an optional case, the reduced-diameter hole 4 is a circular hole, while the central hole 3 is a regular hexagon hole. At this time, the inner diameter of the reduced-diameter hole 4 is smaller than the length of the connection line between two relatively distributed end angles in the regular hexagon. Here, it can even be that the inner diameter of the reduced-diameter hole 4 is much smaller than the length of the connection line between two relatively distributed end angles in the regular hexagon. For example, the reduced-diameter hole 4 can be just a tiny circular hole.

[0052] In the second optional implementation case, a closed reinforcement portion is further formed at the axis center of the tooth roots of multiple teeth; the closed reinforcement portion is located at one end of the central hole 3 away from the structural strengthening portion 2, and the closed reinforcement portion extends to the axial side end of the tooth profile portion 1 away from the structural strengthening portion 2. At this time, that is to say, for the tooth profile portion 1 as a whole, the internal central hole 3 is not in the form of a through hole, but in the form of a blind hole.

[0053] On the basis of the above structure, it should be noted that in order to enable the micro sun gear of this embodiment to simultaneously meet the requirements of meshing transmission with the power shaft 6 and other gears, whether it is the first implementation method or the second implementation method, the axial length of the central hole 3 accounts for 1 / 3 to 2 / 3 of the axial length of the tooth profile portion 1.

[0054] In summary, in this embodiment, by designing a reduced-diameter hole 4 or a closed reinforcement part at one end of the tooth-shaped part 1 away from the structural reinforcement part 2, the overall strength of the tooth-shaped part 1 at one end away from the structural reinforcement part 2 can be enhanced, thereby preventing the occurrence of fracture at the tooth root of this part of the structure of the tooth-shaped part 1. Therefore, for the micro-sized sun gear of this embodiment, considering the actual situation, the tooth root parts at the two axial ends of the tooth-shaped part 1 are most likely to have fracture problems. Therefore, through the cooperation of the structural reinforcement part 2 and the reduced-diameter hole 4 or the closed reinforcement part, protection can be simultaneously formed for the tooth root parts at the two axial ends of the tooth-shaped part 1, improving the service strength of the two axial ends of the tooth-shaped part 1 and effectively increasing the load-bearing torque of the micro-sized sun gear of this embodiment.

[0055] Embodiment 3:

[0056] Please refer to Figures 1 to 4 As shown, on the basis of the micro-sized sun gear of Embodiment 1 or Embodiment 2, this embodiment provides a speed reduction planetary gear system, including: the micro-sized sun gear of Embodiment 1 or Embodiment 2.

[0057] Only the overall structure of the micro-sized sun gear is optimized, and it does not need to be assembled with other components for use. Therefore, the micro-sized sun gear of this embodiment has the advantages of simplified assembly process, reduced production and assembly difficulty, small volume, and high strength, and can bear a greater torque, thus meeting the requirements of the speed reduction planetary gear system for large torque, long life, and compact structure.

[0058] The above specific embodiments have further elaborated on the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above are only specific embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

[0059] In the description of the present invention, it should be understood that the terms indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be construed as a limitation to the present invention.

[0060] In the present utility model, unless otherwise clearly defined and limited, terms such as "installation", "connection", "linkage", "fixation", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral one; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0061] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the utility model product is usually placed during use. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model. In addition, terms such as "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0062] In addition, terms such as "horizontal", "vertical", "overhanging", etc. do not mean that the components are required to be absolutely horizontal or overhanging, but may be slightly inclined. For example, "horizontal" only means that its direction is more horizontal relative to "vertical", and does not mean that the structure must be completely horizontal, but may be slightly inclined.

[0063] In the present utility model, unless otherwise clearly defined and limited, the first feature being above or below the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features between them. Moreover, the first feature being above, over and on the second feature includes the first feature being directly above and obliquely above the second feature, or merely indicating that the horizontal height of the first feature is higher than that of the second feature. The first feature being below, under and beneath the second feature includes the first feature being directly below and obliquely below the second feature, or merely indicating that the horizontal height of the first feature is lower than that of the second feature.

Claims

1. A miniature sun gear, characterized in that: include: Integrally processed toothed part and structural reinforcement part; in The toothed portion includes a plurality of gear teeth evenly distributed along the circumferential direction and a center hole provided at the axis center of the tooth roots of the plurality of gear teeth; The structural reinforcement part is arranged at one axial side end of the toothed part; the structural reinforcement part has an extension hole penetrating the center hole and formed integrally; The cross-sectional shape and size of at least part of the extension hole along the direction perpendicular to the axial direction of the toothed portion are consistent with those of the central hole.

2. The miniature sun gear according to claim 1, characterized in that: The overall cross-sectional shape and size of the extension hole along the direction perpendicular to the axial direction of the toothed portion are consistent with those of the central hole.

3. The miniature sun gear according to claim 2, characterized in that: The structural reinforcement part is a cylindrical structure; and The outer diameter of the structural reinforcement portion is not less than the outer diameter of the tooth tip circle of the toothed portion.

4. The miniature sun gear according to claim 2 or 3, characterized in that: The axial length of the structural reinforcement portion is smaller than the axial length of the toothed portion.

5. The miniature sun gear according to claim 4, characterized in that: The axial length of the structural reinforcement portion is 1 / 3 to 1 / 2 of the axial length of the toothed portion.

6. The miniature sun gear according to claim 2 or 3, characterized in that: The cross section of the central hole along the direction perpendicular to the axial direction of the toothed portion is polygonal.

7. The miniature sun gear according to claim 1, characterized in that: A reduced diameter hole communicating with the center hole is formed at the axis of the tooth roots of the plurality of gear teeth; The reduced diameter hole is located at an end of the central hole away from the structural reinforcement portion, and the reduced diameter hole extends to the axial end of the toothed portion away from the structural reinforcement portion; and The cross-sectional area of ​​the reduced diameter hole along the axial direction perpendicular to the toothed portion is smaller than the cross-sectional area of ​​the central hole along the axial direction perpendicular to the toothed portion.

8. The miniature sun gear according to claim 1, characterized in that: A closed reinforcement portion is also formed at the axis of the tooth roots of the plurality of gear teeth; The closed reinforcement portion is located at one end of the central hole away from the structural reinforcement portion, and the closed reinforcement portion extends to the axial side end of the toothed portion away from the structural reinforcement portion.

9. The miniature sun gear according to claim 7 or 8, characterized in that: The axial length of the central hole accounts for 1 / 3 to 2 / 3 of the axial length of the toothed portion.

10. A planetary gear system, characterized in that: include: A miniature sun gear as claimed in any one of claims 1 to 9.

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