Reduction gear structure

Abstract

To provide a reduction gear structure.SOLUTION: A reduction gear structure includes: drive gears which sequentially surround a circumference from the inside toward the outside and are meshed with each other; at least two planetary gears; and a fixed inner gear. A movable inner gear is arranged in the vicinity of the fixed inner gear, and the planetary gears integrally extend and are engaged with the movable inner gear. The drive gears are arranged along an axial line, so that the planetary gears are driven so as to operate between the drive gears and the fixed inner gear, and due to the presence of a gear number difference between the fixed inner gear and the movable inner gear, the movable inner gear is pushed and moved so as to output power while reducing a speed by the transition of the tooth number difference.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a reduction gear structure, and more particularly, to a reduction gear structure that further simplifies the overall arrangement space and volume and provides a high reduction ratio.

Background Art

[0002] A reduction gear is a precision machine and is used to reduce the rotational speed and increase the torque. When used in a driving device (for example, a motor) with a low rotational speed and a large torque, the power operating at a high speed is reduced in rotational speed by a reduction gear and used to increase the torque.

[0003] Examples of reduction gears in the market include planetary gear types, cycloid types, and harmonic drive (registered trademark) types. There is further a composite reduction gear that combines a planetary gear set and a harmonic drive (registered trademark) reduction mechanism to increase the reduction ratio. The planetary gear set and the harmonic drive (registered trademark) reduction mechanism respectively output multi-stage reduction ratios to meet the usage requirements at the output end.

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, these reduction gears described above are too large in volume. In particular, since the number of members is too large, the arrangement becomes complicated and the occupied space becomes too large, which is disadvantageous for miniaturization and refinement of the length of the axis of the input shaft. In addition, in the design of the conventional composite planetary gear, the smooth operation is ensured by controlling the tooth position angles of each set of planetary gears in the same way. However, in the manufacture of the gear, first, the tooth profile of the involute gear of the internal gear must be comprehensively corrected to eliminate the interference with the planetary gear before it can operate smoothly. For this reason, manufacturing, assembly, or actual operation becomes very difficult, and there are technical problems in applying the conventional composite planetary gear to miniature precision drives.

[0005] Therefore, the inventor of the present invention considered that the above-mentioned drawbacks could be improved, and as a result of intensive studies, the inventor arrived at the proposal of the present invention that effectively improves the above-mentioned problems through a rational design.

[0006] The present invention has been made through intensive research by the inventor in view of the above problems, and its object is to provide a speed reduction mechanism structure that has the effect of making the overall arrangement space and volume more concise and has a large reduction ratio.

Means for Solving the Problems

[0007] To achieve the above object, a speed reduction mechanism structure according to an aspect of the present invention includes a drive gear that is sequentially surrounded from the inside to the outside and is installed so as to mesh with each other, at least two planetary gears, and a fixed internal gear. A movable internal gear is coaxially arranged near the fixed internal gear. The number of teeth of the movable internal gear is different from the number of teeth of the fixed internal gear. Each of the planetary gears has a hollow annular shape, and each of the planetary gears extends integrally to the movable internal gear and meshes with the movable internal gear. The drive gear is arranged along the axis and is used to drive each of the planetary gears so as to operate between the drive gear and the fixed internal gear. And because there is a difference in the number of teeth between the fixed internal gear and the movable internal gear, when each of the planetary gears operates, the movable internal gear is pushed together so as to decelerate and output due to the transition of the difference in the number of teeth.

[0008] Other objects, configurations, and effects of the present invention will become apparent from the following description of the embodiments of the invention.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the speed reduction mechanism of the present invention will be described with reference to the drawings. However, the present invention is not limited to these embodiments, and members, materials, etc. described below can be variously modified within the scope of the gist of the present invention.

[0011] First, the best mode for carrying out the present invention will be described in detail with reference to FIGS. 1 to 4. The speed reduction mechanism according to the present invention includes a drive gear 11 that is sequentially surrounded from the inside to the outside and installed so as to mesh with each other, at least two planetary gears 21, and a fixed internal gear 31. Further, a movable internal gear 41 is coaxially arranged in the vicinity of the fixed internal gear 31, and the housing 51 covers the drive gear 11, each of the planetary gears 21, the fixed internal gear 31, and the movable internal gear 41. Hereinafter, each will be described.

[0012] <Drive Gear 11> It is arranged in the housing 51 along the axis X. The drive gear 11 has an assembly hole 12 opened along the axis X, and the assembly hole 12 is used to connect the power shaft 61. The power shaft 61 is selected as the drive shaft of a motor that supplies rotational power, and supplies rotational power for driving the drive gear 11 to rotate.

[0013] <Planetary Gear 21> The number of the planetary gears 21 is two or more, and in this embodiment, an example is given where the number of the planetary gears 21 is two. Each of the two planetary gears 21 is in a hollow annular shape and has elastic deformation, and the two planetary gears 21 are meshed with the outer periphery of the drive gear 11 so as to surround with an interval at the same arc distance, and the two planetary gears 21 are symmetrically installed with respect to each other. The two planetary gears 21 have the same module and are respectively meshed with the fixed internal gear 31. That is, the two planetary gears 21 are arranged between the drive gear 11 and the fixed internal gear 31, and the fixed internal gear 31 is fixed to the step surface 511 in the housing 51. , the fixed internal gear 31 and the movable internal gear 41 do not contact each other due to the stepped surface. The fixed internal gear 31 and the drive gear 11 have the same axis X. The fixed internal gear 31 itself does not rotate. When the drive gear 11 is driven by the power shaft 61 to rotate, the two planetary gears 21 are driven to rotate synchronously and revolve around the drive gear 11 along the inner periphery of the fixed internal gear 31 to obtain the deceleration output of the first stage. In this embodiment, the two planetary gears 21 are respectively manufactured in a hollow annular shape with a rigid material, maintain a certain rigidity for applying to a use environment with a large load, and have appropriate elastic deformation.

[0014] Specifically, the two planetary gears 21 extend integrally from the fixed internal gear 31 in parallel in the direction of the axis X, and the movable internal gear 41 is coaxially arranged in parallel in the vicinity of the fixed internal gear 31. The movable internal gear 41 and the fixed internal gear 31 have the same axis X, and an output shaft 42 is connected to the movable internal gear 41. The movable internal gear 41 and the fixed internal gear 31 have different modules, and the module of the movable internal gear 41 is larger than the module of the fixed internal gear 31. The number of teeth of the movable internal gear 41 is different from the number of teeth of the fixed internal gear 31, and the movable internal gear 41 and the fixed internal gear 31 have different pitch circle diameters. In this embodiment, the number of teeth of the movable internal gear 41 is 88, the number of teeth of the fixed internal gear 31 is 90, the difference between the number of teeth of the movable internal gear 41 and the number of teeth of the fixed internal gear 31 is 2, and the internal teeth of the fixed internal gear 31 and the movable internal gear 41 are arranged so as to gradually intersect facing the two end positions A and B facing each other. That is, the two positions where the internal teeth of the fixed internal gear 31 and the movable internal gear 41 are symmetric about 180 degrees are aligned and overlapped with each other, and the remaining positions are arranged with a shift in position from each other. The two planetary gears 21 each have a hollow annular shape, and the movable internal gear 41 and the fixed internal gear 31 are meshed with the internal teeth facing each other by the protruding ends 211 protruding integrally from the fixed internal gear 31 respectively. By making the module of the movable internal gear 41 larger than the module of the fixed internal gear 31, the smooth operation of the two planetary gears 21 is ensured.

[0015] In this embodiment, one end of the output shaft 42 is recessed along the axis X to form a receiving portion 43. The receiving portion 43 has an inner circumferential wall 431 and a bottom surface 432 connected to the inner circumferential wall 431. The movable internal gear 41 is fixedly installed corresponding to the inner circumferential wall 431 of the receiving portion 43. The protruding ends 211 of the drive gear 11 and the two planetary gears 21 are respectively extended into the receiving portion 43 and abutted against the bottom surface 432, ensuring the stability of the drive gear 11 and the two planetary gears 21 during operation. At least one bearing unit 52 is installed between the outer periphery of the output shaft 42 and the housing 51. The bearing unit 52 is composed of a rolling bearing or a bush and supports the output shaft 42 to rotate, reducing the friction and vibration during rotation. Also, since the two planetary gears 21 are respectively in a hollow annular shape and have elastic deformation, when the deceleration structure of the present invention performs the modification work of the original standard internal teeth, only a part of the tooth profile of the internal teeth (including the fixed internal gear 31 and the movable internal gear 41) is modified, leaving an appropriate interference area to generate an appropriate frictional resistance. Further, after the planetary gear 21 in a hollow annular shape is elastically deformed by operating and receiving force, the interference amount between the gears becomes smaller, and the planetary gear 21 of the present invention can maintain stable operation even when the planetary frame is not arranged.

[0016] Among other possible embodiments, as shown in FIG. 7, the movable internal gear 41 is directly integrally formed from the inner circumferential wall 431 of the receiving portion 43 of the output shaft 42 and is used to mesh with the protruding ends 211 of the two planetary gears 21. The protruding ends 211 of the drive gear 11 and the two planetary gears 21 are respectively extended into the receiving portion 43 and abutted against the bottom surface 432, similarly ensuring the stability of the drive gear 11 and the two planetary gears 21 during operation.

[0017] Next, with continued reference to FIG. 5, when the power shaft 61 drives the drive gear 11 to operate, the power of the drive gear 11 drives the two planetary gears 21 that mesh with it to rotate, and simultaneously drives the two planetary gears 21 to operate between the drive gear 11 and the fixed internal gear 31, generating a first-stage reduction output. Next, the two planetary gears 21 are simultaneously meshed with the movable internal gear 41 by their protruding ends 211. After the first-stage reduction output is generated, since the fixed internal gear 31 is fixed in the housing 51 and does not rotate, the movable internal gear 41 is driven. By doing so, in the process of the two planetary gears 21 revolving around the drive gear 11 (see FIG. 6), there is a difference in the number of teeth between the movable internal gear 41 and the fixed internal gear 31. Therefore, the two planetary gears 21 gradually push the internal teeth arranged in an intersecting manner between the movable internal gear 41 and the fixed internal gear 31 one by one, and drive the movable internal gear 41 to start rotating. When the two planetary gears 21 are operating, the part where the two planetary gears 21 and the movable internal gear 41 mesh with each other pushes the movable internal gear 41 together to output at a high reduction ratio due to the transition of the difference in the number of teeth, and synchronously drives the output shaft 42 connected to the movable internal gear 41 to generate a second-stage reduction output, which is used for a device that needs to reduce the rotational speed. The reduction mechanism according to the present invention calculates its drive reduction ratio (Gear ratio) according to the following mathematical formula. JPEG0007698698000001.jpg13128Here, the number of teeth of the drive gear 11 is defined as N1, the number of teeth of the fixed internal gear 31 is defined as N3, and the number of teeth of the movable internal gear 41 is defined as N4.

[0018] Next, in this embodiment, the number of teeth of the drive gear 11 is 10, the number of teeth of the two planetary gears is 40, the number of teeth of the fixed internal gear 31 is 90, and the number of teeth of the movable internal gear 41 is 88. Substituting these values into the mathematical formula and calculating, the drive reduction ratio in this embodiment reaches 440.

[0019] To sum up the above, the two-stage deceleration output of the present invention is specifically feasible. The present invention arranges the drive gear 11, the two planetary gears 21, the fixed internal gear 31, and the movable internal gear 41 to be sequentially driven, which not only greatly increases the reduction ratio within the effective space, but also greatly simplifies the structure of the reducer, making the overall arrangement space and volume of the reducer according to the present invention more concise, meeting the requirements of miniaturizing, refining, and assembling the device.

[0020] Furthermore, each gear of the present invention is in a hollow annular shape and has elastic deformation. Therefore, there is an appropriate interference area between each of the planetary gears 21 and the gears (including the drive gear 11, the fixed internal gear 31, and the movable internal gear 41), effectively reducing backlash. It drives reliably, has accurate positioning, and due to the frictional resistance formed in the interference area, when the power shaft 61 driven by the motor stops, a braking effect is further generated, assisting in the control of motion by braking without relying on the motor. When the motor stops, it provides sufficient resistance to execute the automatic locking function. Also, when maintaining a fixed angle, there is no need to operate the motor, greatly reducing the power loss of the motor and saving the power consumption of the motor. Moreover, the planetary gear 21 in a hollow annular shape has a reduced rotational inertia, and the heat generation due to friction during high-speed rotation also decreases, maintaining the temperature when each of the planetary gears 21 operates at high speed, improving its stability and service life.

[0021] Furthermore, in the speed reduction mechanism according to the present invention, the two planetary gears 21 are simultaneously meshed with the fixed internal gear 31 and the movable internal gear 41 at two end positions A and B that are symmetric at 180 degrees, and not only satisfy the requirement of driving with a large reduction ratio by the driving method based on the transition of the tooth number difference, but also ensure the meshing area because the number of meshing teeth is large, resulting in an increase in the output torque, generating a stronger torque and positioning very precisely. In addition, the meshing cycle speed is low, the force balance is uniform, and the operating noise and vibration are further reduced. Moreover, since there is little sliding in the meshing parts, the power loss caused by friction is effectively reduced. When applied to a high reduction ratio, it has the advantages of maintaining high-efficiency power, enabling the motor that supplies power to be miniaturized together.

[0022] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

Explanation of Reference Numerals

[0023] 11 Drive Gear 12 Assembly Hole 21 Planetary Gear 211 Protruding End 31 Fixed Internal Gear 41 Movable Internal Gear 42 Output Shaft 43 Accommodating Portion 431 Inner Peripheral Wall 432 Bottom Surface 51 Housing 511 Step Surface 52 Bearing Unit 61 Power Shaft X Axis A End Position B End Position

Claims

1. A reduction gear structure comprising a drive gear, at least two planetary gears, a fixed internal gear, and a housing, which are sequentially surrounded from the inside out and arranged to mesh with each other. A movable internal gear is coaxially arranged near the fixed internal gear. The number of teeth of the movable internal gear is different from that of the fixed internal gear. Each of the planetary gears has elastic deformation, and each of the planetary gears extends integrally to the movable internal gear and meshes with the movable internal gear. The drive gear is arranged along the axis and is used to drive each of the planetary gears to operate between the drive gear and the fixed internal gear. Since there is a difference in the number of teeth between the fixed internal gear and the movable internal gear, when each of the planetary gears operates, the movable internal gear is pushed together so as to decelerate and output due to the change in the number of teeth difference. The movable internal gear is connected to an output shaft. One end of the output shaft is recessed along the axis to form a receiving portion. The receiving portion has an inner circumferential wall and a bottom surface connected to the inner circumferential wall. The movable internal gear is fixedly installed corresponding to the inner circumferential wall of the receiving portion. The protruding ends of each of the drive gear and the planetary gears extend into the receiving portion and are in contact with the bottom surface. The housing covers the drive gear, each of the planetary gears, the fixed internal gear, and the movable internal gear. A stepped surface is provided on the inner surface of the housing. The fixed internal gear and the movable internal gear are arranged in the housing, and the fixed internal gear and the movable internal gear are prevented from contacting each other by the stepped surface.

2. The drive gear has an assembly hole opened along the axis. The assembly hole is used to supply rotational power by connecting a power shaft and drive the drive gear to rotate. The reduction gear structure according to claim 1, wherein the fixed internal gear, the movable internal gear, and the drive gear have the same axis.

3. Each of the planetary gears is meshed with the outer periphery of the drive gear so as to surround at the same arc distance. Each of the planetary gears is symmetrically arranged with respect to each other. The reduction gear structure according to claim 2, wherein the number of teeth of the movable internal gear is different from that of the fixed internal gear.

4. The module of the movable internal gear is larger than that of the fixed internal gear, each of the planetary gears has the same module, each of the planetary gears extends integrally with the fixed internal gear in a direction parallel to the axis, and each of the planetary gears is meshed with the internal teeth facing each other between the movable internal gear and the fixed internal gear by a protruding end protruding integrally with the fixed internal gear. The speed reduction mechanism according to claim 3, characterized in that.

5. The speed reduction mechanism according to claim 1, characterized in that at least one bearing unit for supporting the output shaft is installed between the outer periphery of the output shaft and the housing.

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