Harmonic reduction transmission device

Abstract

To provide a harmonic reduction transmission device. [Solution] The harmonic reduction transmission device according to the present invention comprises a harmonic reducer connected to a motor so as to transmit power. Sensing parts and transmission parts are formed at both ends of the rotor of the motor, respectively. The harmonic reducer comprises a rigid wheel, a flexible wheel meshed within the rigid wheel, and a waveform generating assembly that drives the flexible wheel to rotate. By using the transmission part as an elliptical disc within the waveform generating assembly, the transmission part transmits power to rotate the flexible bearing and flexible wheel within the waveform generating assembly, simplifying the structural arrangement and outputting a rotational speed of a predetermined reduction ratio.

Description

Technical Field

[0001] The present invention relates to a configuration of a harmonic reducer and a motor, and more particularly, to a harmonic speed reduction transmission device (A harmonic speed reduction transmission device).

Background Art

[0002] The harmonic reducer generates a deceleration effect by elastic deformation of a metal. Generally, it is applied to the transmission structure of an industrial robot or a humanoid robot, and has advantages such as a small volume, a light weight, a high loading capacity, a high motion accuracy, and a large single-stage transmission ratio.

[0003] In a conventional harmonic reducer, a rigid wheel, a flexible wheel, and a waveform generating assembly are usually arranged in a housing. Hereinafter, the configurations of each member will be described.

[0004] The rigid wheel is a hollow ring-shaped wheel body, which is fixed in the housing and has a plurality of internal teeth distributed in an annular shape, and provides a guiding action when the flexible wheel rotates.

[0005] The flexible wheel is also a hollow ring-shaped wheel body, and has a deformable thin wall portion and a thick wall portion capable of maintaining a rigid strength. The thin wall portion has a smooth inner wall surface and a plurality of external teeth distributed in an annular shape and capable of meshing with the internal tooth portion of the rigid wheel. The number of teeth of the external teeth is usually less than that of the internal teeth (generally, two less). The thick wall portion is used as a power output end of the harmonic reducer.

[0006] The waveform generation assembly is a columnar assembly comprising an elliptical disc and a flexible bearing tightly coupled to the outer circumference of the elliptical disc. The elliptical disc can be used as the power input end of the harmonic reducer, and the flexible bearing is a thin-walled ball bearing, the outer wall of which can be tightly coupled to the inner wall surface of the flexible wheel. [Overview of the project] [Problems that the invention aims to solve]

[0007] Therefore, when the harmonic reducer drives the elliptical disk to rotate by rotational kinetic energy, the elliptical disk is able to sequentially deform the thin-walled portion of the flexible bearing and the flexible wheel into a matching ellipse shape, thereby driving the flexible wheel to wind up within the rigid wheel and rotate in the opposite direction. During this period, the number of teeth on the external teeth of the flexible wheel is slightly less than the number of teeth on the internal teeth of the rigid wheel, and the thin-walled portion of the flexible wheel is deformed into an ellipse shape. As a result, only the external teeth at two opposing ends on the long axis of the ellipse are able to mesh with the internal teeth of the rigid wheel, and the flexible wheel rotates slowly on the internal teeth of the rigid wheel at the same circumference. This means that for each rotation (360 degrees) of the elliptical disk, the flexible wheel can only rotate in the opposite direction by a small arc (determined by the reduced number of teeth on the external teeth of the flexible wheel), significantly reducing the rotational speed of the flexible wheel relative to the elliptical disk and achieving a deceleration effect. In other words, the thick wall portion of the flexible wheel becomes capable of outputting rotational kinetic energy at a predetermined reduction ratio.

[0008] Furthermore, the aforementioned harmonic reducer typically required a motor to be coupled to it to constitute a harmonic reduction transmission device. The motor provides rotational kinetic energy to the harmonic reducer in order to provide the rotational kinetic energy after reduction to an external source. The motor excites the rotor to rotate via a stator, and the rotor is coupled to the thick wall portion of the flexible wheel by at least one coupling kit to transmit the energy. However, this had the disadvantage of making the assembly process complex and making it difficult to reduce the volume of the structure.

[0009] Furthermore, conventional patent documents, for example, Patent Document 1 and Patent Document 2 below, present representative examples of the above-mentioned harmonic reducer and motor transmission coupling technology. However, these patents required a coupling kit similar to, or identical in structure to, the aforementioned coupling kit in order to transmit the rotational kinetic energy of the motor rotor to the harmonic reducer. Therefore, overcoming the challenge of a complex assembly process was difficult, and when it was necessary to output kinetic energy at a specific reduction ratio, the problem arose of difficulty in miniaturizing the volume of the structure.

[0010] The aforementioned technical shortcomings had a significant impact on the research goals of miniaturizing and improving the precision of industrial and humanoid robots, and there was room for improvement.

[0011] This invention was made through diligent research by the inventors in view of the above-mentioned problems. Its purpose is to simplify the assembly process by emphasizing the integration between the motor rotor and the elliptical disk of the waveform generation assembly, and to further reduce the internal space of the transmission unit that realizes harmonic reduction transmission, thereby achieving a smaller structural volume. [Means for solving the problem]

[0012] To achieve the above objective, a harmonic reduction transmission device according to one aspect of the present invention comprises a harmonic reducer and a motor arranged along the same axial path within a housing. The harmonic reducer includes a rigid wheel fixed within the housing, a flexible wheel meshed within the rigid wheel, and a waveform generating assembly that drives the flexible wheel to rotate, the waveform generating assembly comprising an elliptical disc and a flexible bearing coupled between the elliptical disc and the flexible wheel. The motor includes a stator fixed within the housing and a rotor pivotally mounted within the stator. The rotor has a sensing portion and a transmission portion facing the sensing portion. The surface of the sensing portion has at least one polarity pair formed by a permanent magnet, and the sensing portion is located within the stator so as to be subjected to electromagnetic induction by the stator. In particular, the elliptical disc is composed of the transmission portion.

[0013] As can be seen from the technical features described above, the present invention has the effect of reducing the number of structural components and simplifying the assembly process, in particular, because the elliptical disc of the waveform generation assembly is integrally formed with the motor rotor, eliminating the need to add the conventional connecting kit between the rotor and the elliptical disc.

[0014] According to one aspect of the present invention, the rigid wheel has a plurality of internal teeth distributed in an annular manner, and the flexible wheel has a deformable thin-walled portion and a thick-walled portion capable of maintaining rigidity and strength, wherein the thin-walled portion has a smooth inner wall surface and a plurality of external teeth distributed in an annular manner around the outer periphery of the thin-walled portion. The flexible wheel is coupled to the flexible bearing by the inner wall surface and is meshed with a portion of the internal teeth of the rigid wheel by the external teeth.

[0015] As a result, the present invention is characterized in that the housing is specially designed so that the housing base and housing cover, which are formed in half, are pivotally connected to each other to form the housing, the housing base is used to fix the rigid wheel, the housing cover is used to fix the thick wall portion of the flexible wheel, and the housing cover serves as the power output terminal of the harmonic reduction transmission device.

[0016] More specifically, a first housing chamber is formed within the housing base, a second housing chamber communicating with the first housing chamber is formed within the housing cover, and the sensing portions of the stator and rotor are located within the first housing chamber. The transmission portion of the rotor extends into the second housing chamber, and the harmonic reducer is located between the first and second housing chambers. Furthermore, a central pivot hole is formed in the rotor, and a central hub portion is formed in the housing that can penetrate into the central pivot hole, and the rotor is pivotally mounted between the central hub portion and the stator via the central pivot hole. The central hub portion is formed within the housing base, and mounting holes are formed in the central hub portion, and a central column that can be pivotally mounted into the mounting holes extends within the housing cover.

[0017] Comparing the above-mentioned technical features with those of the prior art, the present invention technically contributes to achieving the objective of reducing the internal space of the device body and miniaturizing the volume of the structure.

[0018] Furthermore, an annular guide groove is formed in at least one of the housing base and the rigid wheel, and a protruding ring that can be guided by the guide groove is formed in the housing cover. In this way, the housing cover, which is used as the power output end, helps to increase stability when it rotates relative to the housing base.

[0019] In addition, the above-described housing base and housing cover may be held so as to be pivotally attached to each other, and may have a housing chamber inside. As long as the remaining structural features can be made compatible or slightly changed, these are also all included in the spirit and scope of application of the present invention.

[0020] From the descriptions in the following specification and drawings, at least the following matters will become clear.

Brief Description of the Drawings

[0021] [Figure 1] It is a schematic exploded view showing a harmonic speed reduction transmission device according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view shown in FIG. 1. [Figure 3] Explaining the cross-section of the housing shown in FIG. 2, showing that the housing is formed by a housing base and a housing cover. [Figure 4] It is an assembly explanatory view of the rotor and the flexible wheel of the motor shown in FIG. 2, explaining the mode in which the transmission part of the rotor is connected to the flexible wheel via a flexible bearing.

Modes for Carrying Out the Invention

[0022] Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the invention according to the claims. Also, not all combinations of features described in the embodiments are essential for the solution means of the invention.

[0023] First, an example of a specific embodiment of the harmonic speed reduction transmission device of the present invention will be described while referring to FIGS. 1 to 4.

[0024] As the main members of the harmonic speed reduction transmission device according to an embodiment of the present invention, it includes a housing 20, and a harmonic speed reducer 30 and a motor 40 arranged along the same axial path within the housing 20. As shown in FIGS. 1 and 2, the harmonic speed reducer 30 includes a rigid wheel 31 fixed along the same axial path within the housing 20, a flexible wheel 32 meshed within the rigid wheel 31, and a waveform generation assembly 33 for driving the flexible wheel 32 to rotate. The waveform generation assembly 33 includes an elliptical disk 331 and a flexible bearing 332 coupled between the elliptical disk 331 and the flexible wheel 32. The motor 40 may be one of a brushless DC motor and a permanent magnet AC synchronous motor, and includes a stator 41 fixed within the housing 20 and a rotor 42 pivotally attached within the stator 41.

[0025] FIGS. 1 and 3 show that the housing 20 shown in FIG. 2 is in a ring form, and is formed by pivotally attaching a ring-shaped housing base 21 and a ring-shaped housing cover 22 formed in a half body. A plurality of inner surfaces presenting ring-shaped steps are respectively formed on the housing base 21 and the housing cover 22, and a first housing chamber 210 within the housing base 21 and a second housing chamber 220 within the housing cover 22 that can communicate with the first housing chamber 210 are configured, and are used to accommodate the harmonic speed reducer 30 and the motor 40 shown in FIG. 2.

[0026] Furthermore, the housing base 21 can be considered as the fixed end of the transmission device for mounting at the desired end of the device. A central hub portion 211 protruding toward the first housing chamber 210 can be formed in the center of the housing base 21, and a mounting hole 212 is provided within the central hub portion 211. A central column 221 that penetrates to the mounting hole 212 is formed in the center of the housing cover 22 and is used to mount a first bearing 51 between the mounting hole 212 and the central column 221. The central column 221 and the first bearing 51 allow the housing cover 22 to be pivotally attached to the mounting hole 212. Furthermore, an annular guide groove 213 can be formed at one end of the housing base 21 adjacent to the housing cover 22, and a protruding ring 222 guided by the guide groove 213 is formed on the housing cover 22, and the housing cover 22 is made rotatable freely and stably relative to the housing base 21 in order to make the housing cover 22 the power output terminal of this transmission device.

[0027] As described above, the central hub portion 211, mounting holes 212, and guide grooves 213 of the housing base 21 may be modified to be formed within the housing cover 22, thereby changing the formation positions of the central column 221 and protruding ring 222 of the housing cover 22 to be formed within the housing base 21. In other words, any configuration in which the housing base 21 and the housing cover 22 are pivotally connectable to each other and have housing chambers communicating internally is within the technical scope of the modifiable embodiments of the present invention.

[0028] Figures 1 and 2 show the arrangement of the rigid wheel 31 and the flexible wheel 32. The rigid wheel 31 has an annular flange 311 formed on it, and the rigid wheel 31 is fixed to the inner surface adjacent to the housing cover 22 of the housing base 21 in a manner in which it is tightly fitted by the outer surface of the protruding ring 311, so that the rigid wheel 31 does not move during the deceleration transmission process. In addition, the rigid wheel 31 has a plurality of internal teeth 312 that are distributed in an annular shape and are used to generate a guiding action for the flexible wheel 32. Furthermore, the guide groove 213 is also formed on the rigid wheel 31 to guide the protruding ring 222 of the housing cover 22.

[0029] Furthermore, the flexible wheel 32 has a deformable thin-walled portion 321 and a thick-walled portion 322 that can maintain rigidity and strength. The thin-walled portion 321 has a smooth inner wall surface 321a and a plurality of external teeth 321b distributed in an annular pattern around the outer surface of the thin-walled portion 321. The flexible wheel 32 is coupled to the flexible bearing 332 by the inner wall surface 321a, and the external teeth 321b mesh with a portion of the internal teeth 312 of the rigid wheel 31, allowing the rigid wheel 31 to guide the flexible wheel 32 to rotate. Screws are driven into the thick-walled portion 322 to fix the flexible wheel 32 to the housing cover 22, and the housing cover is used as the power output terminal of this transmission device by driving the flexible wheel 32 synchronously to rotate the housing cover 22.

[0030] Figure 4 shows details of the arrangement between the rotor 42 and the flexible wheel 32 of the motor 40 shown in Figure 2. The rotor 42 has a sensing unit 421 and a transmission unit 422 facing the sensing unit 421 formed along the axial direction. The sensing unit 421 is located within the stator 41 so as to receive electromagnetic induction from the stator 41, and the elliptical disc 331 of the waveform generation assembly 33 is composed of the transmission unit 422. Furthermore, the sensing unit 421 is formed by coupling a plurality of permanent magnets 421b to a magnet sheet 421a having a cylindrical cross-section, and each of the plurality of permanent magnets 421b is capable of forming at least one polarity pair with the outside being an N pole and an S pole. In the example of Figure 4, the surface of the sensing unit 421 has a plurality of polarity pairs; however, in practice, only one polarity pair is sufficient to receive electromagnetic induction excited by the energization of the coils of the stator 41, and drive the rotor 42 to generate rotational kinetic energy. Furthermore, the cross-section of the transmission section 422 is elliptical and can be the elliptical disc 331 of the waveform generation assembly 33. As shown in Figure 4, a central pivot hole 424 is formed in the rotor 42. As shown in Figure 2, at least one second bearing 52 is arranged in the central pivot hole 424, so that the rotor 42 can be pivotally mounted between the central hub section 211 and the stator 41. Figure 4 further illustrates the structural features of the thin-walled section 321, thick-walled section 322, inner wall surface 321a, and outer teeth 321b of the flexible wheel 32 shown in Figure 2, and the features of the arrangement in which the flexible bearing 332 can be positioned between the inner wall surface 321a of the flexible wheel 32 and the transmission section 422 (i.e., the elliptical disc 331) of the rotor 42.

[0031] Here, when the stator 41 of the motor 40 is excited to rotate the rotor 42, the transmission unit 422 (i.e., the elliptical disc 331) located on the rotor 42 follows and rotates, and the flexible bearing 332 and the thin-walled portion 321 of the flexible wheel 32 sequentially deform into a matching ellipse shape, driving the flexible wheel 32 to wind up within the rigid wheel 31 and rotate in the opposite direction. At this time, the number of teeth on the external teeth 321b of the flexible wheel 32 is less than (usually two fewer than) the internal teeth 312 of the rigid wheel 31, and the thin-walled portion 321 of the flexible wheel 32 is deformed into an ellipse shape. As a result, only the two opposing ends of the external teeth 321b on the long axis of the ellipse of the flexible wheel 32 are actually able to mesh with a portion of the internal teeth 312 of the rigid wheel 31, and the flexible wheel 32 rotates slowly on the internal teeth 312 of the rigid wheel 31 with a circumference of the same size. More specifically, for each rotation (360 degrees) of the rotor 42 having the elliptical disc 331, the flexible wheel 32 rotates in the opposite direction by a small arc of the 360-degree rotation (determined by the decreasing number of teeth on the external teeth of the flexible wheel). The housing cover 22, which is fixed to the flexible wheel 32 as an integral part of it, outputs a rotational speed of a predetermined reduction ratio so that it rotates more slowly than the rotational speed generated by the rotor 42, thereby achieving a predetermined harmonic reduction effect.

[0032] As shown in Figure 2, with the above-described structure, the sensing parts 421 of the stator 41 and the rotor 42 are located within the first housing chamber 210, the transmission part 422 (or elliptical disc 331) of the rotor 42 can extend into the second housing chamber 220, and the harmonic reducer 30 can be positioned between the first housing chamber 210 and the second housing chamber 220. Since the transmission part 422 of the rotor 42 can be used as the elliptical disc 331 of the waveform generation assembly 33, there is no need to add a connecting kit between the rotor 42 and the elliptical disc 331, which significantly reduces the number of structural components and simplifies the assembly process. The present invention certainly makes a technical contribution to achieving the objective of miniaturizing the volume of the structure by reducing the internal space of the transmission device.

[0033] Although embodiments of the present invention have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments, and design changes and the like that do not depart from the spirit of the present invention are also included. [Explanation of Symbols]

[0034] 20 Housing 21 Housing Base 210 First Housing Chamber 211 Central hub section 212 mounting holes 213 Guide groove 22 Housing Cover 220 Second Housing Chamber 221 Central Pillar 222 Protruding Ring 30 Harmonic reducer 31 Rigid wheels 311 Annular flange 312 Inner teeth 32 Flexible Wheels 321 Thin-walled section 321a Inner wall surface 321b External teeth 322 Thick wall section 33 Waveform generation assembly 331 Elliptical disc (or transmission unit) 332 Flexible bearing 40 motors 41 Stator 42 rotors 421 Sensing part 421a Magnetic Sheet 421b Permanent magnet 422 Transmission section (or elliptical disc) 424 Center pivot hole 51 First bearing 52 Second bearing

Claims

1. A harmonic reduction transmission device arranged within a housing along the same axial path, A harmonic reducer comprising a rigid wheel fixed within the housing, a flexible wheel meshed within the rigid wheel, and a waveform generating assembly that drives the flexible wheel to rotate, wherein the waveform generating assembly comprises an elliptical disc and a flexible bearing coupled between the elliptical disc and the flexible wheel, The motor includes a stator fixed within the housing and a rotor pivotally mounted within the stator, Here, the rotor has a sensing unit and a transmission unit facing the sensing unit, the sensing unit is located within the stator so as to receive electromagnetic induction from the stator, and the elliptical disc is composed of the transmission unit. The rotor is further formed with a central pivot hole, and the housing is formed with a central hub portion that can penetrate into the central pivot hole, and the rotor is pivotally mounted between the central hub portion and the stator via the central pivot hole. The harmonic reduction transmission device is characterized in that the housing is formed by the mutual pivoting of a housing base and a housing cover, the central hub portion is formed within the housing base, mounting holes are formed in the central hub portion, and a central column that can be pivotally attached within the mounting holes extends within the housing cover.

2. The harmonic reduction transmission device according to claim 1, characterized in that the rigid wheel has a plurality of internal teeth distributed in an annular manner, the flexible wheel has a deformable thin-walled portion and a thick-walled portion capable of maintaining rigid strength, the thin-walled portion has a smooth inner wall surface and a plurality of external teeth distributed in an annular manner around the outer periphery of the thin-walled portion, the flexible wheel is coupled to the flexible bearing by the inner wall surface and meshes with a portion of the internal teeth of the rigid wheel by the external teeth.

3. The harmonic reduction transmission device according to claim 2, characterized in that the housing base is used to fix the rigid wheel, and the housing cover is used to fix the thick wall portion of the flexible wheel, thereby the housing cover serves as the power output terminal of the harmonic reduction transmission device.

4. The harmonic reduction transmission device according to claim 2, characterized in that a first housing chamber is formed within the housing base, a second housing chamber communicating with the first housing chamber is formed within the housing cover, the sensing portions of the stator and rotor are located within the first housing chamber, the transmission portion of the rotor extends into the second housing chamber, and the harmonic reduction gear is located between the first housing chamber and the second housing chamber.

5. The harmonic reduction transmission device according to claim 1 or 4, characterized in that the surface of the sensing portion of the rotor has at least one polarity pair formed by a permanent magnet.

6. The harmonic reduction transmission device according to claim 1, characterized in that an annular guide groove is formed in at least one of the housing base and the rigid wheel, and a protruding ring that can be guided by the guide groove is formed in the housing cover.

Images