A cycloidal pinwheel reducer

Abstract

A cycloidal pinwheel reducer is disclosed. This invention solves the problems of complex structure and inconvenient disassembly and assembly in existing cycloidal pinwheel reducers. It includes a housing, an input shaft, an output flange, a cycloidal wheel, a cycloidal profile curve, and a connecting shaft; a first bushing, on which the housing has an arc-shaped cycloidal profile curve corresponding to its position, and the first bushing fits against the cycloidal profile curve on the housing to form a rolling fit; a second bushing, fitted onto the connecting shaft; the first and second bushings are located on the same side of the cycloidal wheel; and transmission holes, multiple of which are circumferentially distributed on the output flange; the output flange is inserted axially along the input shaft and is located on the same side of the cycloidal wheel as the first and second bushings; the second bushing is eccentrically positioned relative to the transmission holes and fits against the inner wall of the transmission holes to form a rolling fit. This invention also has advantages such as simple structure, convenient assembly, easy maintenance, reliable operation, and long service life.

Description

Technical Field

[0001] This invention relates to a speed reduction mechanism, specifically a cycloidal pinwheel reducer. Background Technology

[0002] With the development of industrial technology, factory automation and intelligence place increasingly higher demands on the performance of mechanical equipment transmissions. The development trend of speed reducers is towards high precision, lightweight, high load-bearing capacity, and miniaturization. Currently, there are many types of speed reducers on the market, including common planetary speed reducers, gear reducers, and cycloidal pinwheel reducers. As a new type of structure, the cycloidal pinwheel reducer is a planetary gear transmission device with a small tooth difference. It involves multiple teeth meshing simultaneously, resulting in high transmission capacity. It also boasts advantages such as compact structure, small size, light weight, and high efficiency, and is widely used in mining, metallurgy, chemical, defense, and lifting and transportation industries.

[0003] To improve the precision and load-bearing capacity of the reducer, as well as to achieve lightweight and miniaturization, the applicant invented a cycloidal wheel reducer and applied for a Chinese invention patent (application publication number CN110285198A). This reducer includes two cycloidal wheels, with several circumferentially distributed cycloidal bearings on the outer circumference of each wheel. The inner wall of the outer shell forms an arc-shaped cycloidal profile curve corresponding to the positions of the cycloidal bearings. The cycloidal bearings and the cycloidal profile curve fit together to form a rolling fit, changing the existing sliding fit to a rolling fit, reducing friction and improving transmission efficiency. However, its output structure remains a conventional design, with two cycloidal wheels and pin holes on each wheel. An output bearing can be installed in the pin holes, and the output shaft passes through the pin holes to form a linkage with the cycloidal wheels. Because the pin holes and output bearings are located on the inner side of the cycloidal wheels relative to the cycloidal bearings, not only is the number of pin holes and output shafts reduced, but the corresponding number of pins is also reduced, resulting in a short output lever arm. Especially in more precise applications, such as humanoid robot joints (e.g., wrist joints), not only are miniaturized, high-precision, lightweight, and high-load-bearing capacity required, but also long service life and ease of disassembly and maintenance are also necessary. Existing cycloidal gear reducers have relatively complex structures. Bearings are usually installed between the cycloidal gear and the second mounting component, or between the cycloidal gear and the housing, and these bearings are typically located on both sides (top and bottom) of the cycloidal gear to reduce friction. In miniaturized cycloidal gear reducers, the bearing walls are thinner, resulting in weaker impact resistance. If the bearing breaks, the balls will affect the movement of other normal components inside the housing, making product maintenance difficult and disassembly and assembly cumbersome. Summary of the Invention

[0004] To address the problems of complex structure and inconvenient disassembly and assembly in existing cycloidal pinwheel reducers, this invention provides a cycloidal pinwheel reducer.

[0005] The technical solution of this invention is: a cycloidal pinwheel reducer, comprising a housing, an input shaft, an output flange, and a cycloidal wheel; the input shaft and the output flange are coaxially arranged and rotatably mounted on the housing; the cycloidal wheel is mounted on the input shaft and eccentrically arranged relative to the input shaft, and further comprising: A connecting shaft is provided on the cycloidal wheel, and there are multiple connecting shafts that are evenly distributed circumferentially on the cycloidal wheel; The first bushing is sleeved on the connecting shaft; the housing has a cycloidal profile curve with arc teeth at the position corresponding to the first bushing, and the first bushing fits into the cycloidal profile curve on the housing to form a rolling fit. The second bushing is fitted onto the connecting shaft; the first bushing and the second bushing are located on the same side of the cycloidal wheel; The transmission holes are multiple in number and are circumferentially distributed on the output flange. The output flange is inserted along the axial direction of the input shaft and is located on the same side of the cycloidal wheel as the first bushing and the second bushing. Each transmission hole is provided with the second bushing. The second bushing is eccentrically positioned relative to the transmission hole and fits against the inner wall of the transmission hole to form a rolling fit.

[0006] As a further improvement of the present invention, gaps are provided between the first bushing and the connecting shaft, and between the second bushing and the connecting shaft. The first bushing and the connecting shaft are concentrically arranged and rotatably mounted on the connecting shaft, and the second bushing and the connecting shaft are concentrically arranged and rotatably mounted on the connecting shaft.

[0007] As a further improvement of the present invention, the first bushing and the second bushing are integrally formed from PEEK or steel materials.

[0008] As a further improvement of the present invention, the wall thickness of the first bushing and the second bushing is 0.8mm-1.4mm.

[0009] As a further improvement of the present invention, the housing includes an outer shell and a cover plate, the cover plate is placed outside the output flange and is detachably connected to the cover plate, and the first bushing and the second bushing are arranged facing the cover plate side.

[0010] As a further improvement of the present invention, a first bearing is provided between the input shaft and the cycloidal wheel, and an eccentric portion is provided on the input shaft at the first bearing.

[0011] As a further improvement of the present invention, the cycloidal wheel is provided with an insertion hole, the output flange is provided with a first mounting part and a second mounting part, the first mounting part is disposed through the insertion hole, and a second bearing is provided between the output flange and the housing. There are two second bearings, which are respectively disposed on the outer wall of the first mounting part and the second mounting part and on the upper and lower sides of the cycloidal wheel.

[0012] As a further improvement of the present invention, a third bearing is provided between the input shaft and the output flange. There are two third bearings, which are respectively located on the inner walls of the first mounting part and the second mounting part and on the upper and lower sides of the cycloidal wheel.

[0013] The beneficial effects of this invention are: it reduces the number of cycloidal wheels and their bearings, resulting in fewer parts, a more compact structure, and further miniaturization; the first and second bushings share a single connecting shaft, increasing not only the length of the output lever arm but also the number of bushings (first and second) and the connecting shaft, thus providing greater load-bearing capacity within the same dimensions compared to existing cycloidal pinwheel reduction mechanisms; replacing the bearings on the cycloidal wheel with bushings enhances the product's impact resistance, prevents bushing breakage, and extends the product's service life; the first and second bushings and the output flange are located on the same side, facilitating easy assembly and disassembly and maintenance. This invention also boasts advantages such as simple structure, convenient assembly, easy maintenance, reliable operation, and long service life. Attached Figure Description

[0014] Appendix Figure 1 This is a schematic diagram of the structure of an embodiment of the present invention.

[0015] Appendix Figure 2 This is a cross-sectional structural diagram of an embodiment of the present invention.

[0016] Appendix Figure 3 This is a schematic diagram of the exploded structure according to an embodiment of the present invention.

[0017] Appendix Figure 4 This is a schematic diagram of an explosion structure from another direction according to an embodiment of the present invention.

[0018] Appendix Figure 5 This is a schematic diagram of an explosion structure from another direction according to an embodiment of the present invention.

[0019] Appendix Figure 6 This is a schematic diagram of an explosion structure from another direction according to an embodiment of the present invention.

[0020] In the diagram, 1. Housing; 11. Cycloidal profile curve; 12. Outer shell; 13. Cover plate; 2. Input shaft; 21. Eccentric part; 3. Output flange; 31. Transmission hole; 32. First mounting part; 33. Second mounting part; 4. Cycloidal wheel; 41. Connecting shaft; 42. First bushing; 43. Second bushing; 44. Clearance; 45. Insertion hole; 5. First bearing; 6. Second bearing; 7. Third bearing. Detailed Implementation

[0021] The following description, in conjunction with the accompanying drawings, further illustrates this embodiment: Depend on Figure 1 Combination Figure 2-6As shown, a cycloidal pinwheel reducer includes a housing 1, an input shaft 2, an output flange 3, and a cycloidal wheel 4. The input shaft 2 and the output flange 3 are coaxially arranged and rotatably mounted on the housing 1. The cycloidal wheel 4 is mounted on the input shaft 2 and eccentrically arranged relative to the input shaft 2. The input shaft is typically rotatable relative to the housing, and one end of it can be connected to a motor to achieve rotary input. The reducer also includes: A connecting shaft 41 is provided on the cycloidal wheel 4. There are multiple connecting shafts 41 and they are evenly distributed circumferentially on the cycloidal wheel 4. The first bushing 42 is sleeved on the connecting shaft 41; the housing 1 has a cycloidal profile curve 11 with arc teeth at the position corresponding to the first bushing 42, and the first bushing 42 and the cycloidal profile curve 11 on the housing 1 fit together to form a rolling fit. The second bushing 43 is sleeved on the connecting shaft 41; the first bushing 42 and the second bushing 43 are located on the same side of the cycloidal wheel 4. Multiple transmission holes 31 are circumferentially distributed on the output flange 3. The output flange 3 is inserted along the axial direction of the input shaft 2 and is located on the same side of the cycloidal wheel 4 with the first bushing 42 and the second bushing 43. Each transmission hole 31 is provided with a second bushing 43. The second bushing 43 is eccentrically positioned relative to the transmission hole 31 and fits against the inner wall of the transmission hole 31 to form a rolling fit. Specifically, the multiple transmission holes 31 are circumferentially distributed on the output flange with the rotation center of the input shaft as the center. The beneficial effects of this invention are: it reduces the number of cycloidal wheels and their bearings, resulting in fewer parts, a more compact structure, and further miniaturization; the first and second bushings share a single connecting shaft, increasing not only the length of the output lever arm but also the number of bushings and connecting shafts, thus providing greater load-bearing capacity within the same dimensions compared to existing cycloidal pinwheel reduction mechanisms; replacing the bearings on the cycloidal wheel with bushings enhances the product's impact resistance, preventing breakage within the same dimensions and extending the product's service life; more bushings and connecting shafts can be installed on the same cycloidal wheel, further increasing the product's load-bearing capacity; and the first and second bushings and output flange are located on the same side, facilitating easy assembly and disassembly and maintenance. This invention also boasts advantages such as simple structure, convenient assembly, easy maintenance, reliable operation, and long service life. The working process of this invention is as follows: The input shaft is driven to rotate by a motor. Since the input shaft and the cycloidal wheel are eccentrically set, the input shaft can drive the cycloidal wheel to revolve. During the revolution, due to the interaction between its connecting shaft and the first bushing, the cycloidal wheel can generate its own rotation. Through the cooperation of the second bearing and the transmission hole, the synchronous rotation of the output flange is realized, thereby realizing the speed reduction transmission function.

[0022] A gap 44 is provided between the first bushing 42 and the connecting shaft 41, and between the second bushing 43 and the connecting shaft 41. The first bushing 42 and the connecting shaft 41 are concentrically and rotatably mounted on the connecting shaft 41, and the second bushing 43 and the connecting shaft 41 are concentrically and rotatably mounted on the connecting shaft 41. This structure allows rolling friction to occur between the first bushing and the housing, and between the second bushing and the transmission hole (output flange). The first bushing, the second bushing, and the connecting shaft can also roll relative to each other, making rotation easier and less wear-prone. In this invention, the connecting shafts are all positioned facing the cover plate. The first bushing and the second bushing are located on the same side of the cycloidal wheel. When the cycloidal wheel revolves under the drive of the input shaft, it is simultaneously affected by the interaction between the first bushing and the connecting shaft, causing it to rotate along the eccentric portion. Under the interaction between the second bushing and the transmission hole, the output flange rotates synchronously with the rotation of the cycloidal wheel, thereby achieving rotational output. Compared to existing bearings used at the connecting shaft, the first bushing of this invention is smaller, allowing for a greater number of connecting shafts and bushings, further achieving miniaturization; it also has a greater load-bearing capacity. In actual operation, it will not shatter upon impact, preventing steel balls from entering other holes and affecting normal product operation. In contrast, with existing bearings at the connecting shaft, if one bearing fails, the product is scrapped and cannot be repaired. Even if the bushing of this invention is damaged by impact, it will only undergo simple deformation, with minimal impact on product performance. Therefore, it results in a longer product lifespan, higher impact resistance under the same conditions, and stronger load-bearing capacity.

[0023] Both the first bushing 42 and the second bushing 43 are integrally molded from PEEK (polyetheretherketone) or steel. Specifically, the first and second bushings can be integrally molded from wear-resistant resin, allowing for more bushings to be installed under the same conditions, thus improving the product's load-bearing capacity and impact resistance. Using bushings also effectively reduces friction and extends the product's service life. Alternatively, the first and second bushings can also be integrally molded from steel. Compared to existing bearing-based designs, this allows for more bushings to be installed under the same conditions, further improving the product's load-bearing capacity and impact resistance. In actual production and use, the first bushing can be made of either PEEK or steel, while the second bushing can be made of either steel or PEEK.

[0024] The wall thickness of the first bushing 42 and the second bushing 43 is 0.8mm-1.4mm. Typically, the wall thickness of the first and second bushings in this invention is 1mm. This invention is designed for the wrist joint size of humanoid robots, requiring small size, strong load-bearing capacity, and good impact resistance. That is, the wall thickness of this invention is approximately 1mm, and the overall diameter is approximately 4mm. However, existing bearing-type transmissions have a minimum bearing wall thickness of at least 4mm; even with a 7mm bearing, the smallest 2mm inner hole (taking our equivalent inner hole as an example) makes the bearing very fragile, i.e., with weak impact resistance. Of course, in applications with larger dimensions, the bushings of this invention can also be replaced by bearings.

[0025] Specifically, there are 16 first bushings 42 and 16 second bushings 43. Of course, in actual production and use, the number of first and second bushings can be adjusted as needed. This invention increases the load-bearing capacity of the product by increasing the number of first and second bushings, and uses resin bushings to improve the product's wear resistance and impact resistance. At the same time, it minimizes the product's size, making it suitable for more precise applications and broadening its applicability. Generally, the number of grooves or holes formed by the cycloidal profile curve 11 is greater than the number of first bushings. For example, with 16 first bushings, 17 grooves or holes can typically be formed on the cycloidal profile curve.

[0026] The housing 1 includes an outer shell 12 and a cover plate 13. The cover plate 13 covers the output flange 3 and is detachably connected to it. The first bushing 42 and the second bushing 43 are positioned facing the cover plate 13. This structure facilitates product disassembly and assembly. After removing the cover plate, the second bushing and the first bushing can be quickly replaced. The structure is simple, and even slight deformation of the second bushing and the first bushing will not affect the operation and performance of the product. Even if the second bushing and the first bushing are damaged, it is not necessary to remove the output flange or the cycloidal wheel, making overall product maintenance convenient.

[0027] A first bearing 5 is provided between the input shaft 2 and the cycloidal wheel 4, and the input shaft 2 has an eccentric part 21 at the first bearing 5. The first bearing makes the rotation of the input shaft easier and less prone to wear.

[0028] The cycloidal wheel 4 has an insertion hole 45, and the output flange 3 has a first mounting part 32 and a second mounting part 33. The first mounting part 32 passes through the insertion hole 45. Two second bearings 6 are provided between the output flange 3 and the housing 1, respectively located on the outer walls of the first mounting part 32 and the second mounting part 33, and on the upper and lower sides of the cycloidal wheel 4. Two third bearings 7 are provided between the input shaft 2 and the output flange 3, respectively located on the inner walls of the first mounting part 32 and the second mounting part 33, and on the upper and lower sides of the cycloidal wheel 4. The arrangement of the first and second mounting parts makes the rotation of the output flange smoother, meaning that both the upper and lower sides of the output flange are reliably limited. During rotation, the second and third bearings reduce friction, improving rotation efficiency, reducing consumption, and extending service life. Compared to existing output flanges with only one bearing, this design results in smoother operation, avoids the use of higher-specification bearings, reduces costs, and makes reasonable use of the internal space of the housing without increasing the overall product volume.

[0029] In the description of this invention, it should be noted that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0031] Please note to all technical personnel: Although the present invention has been described according to the specific embodiments above, the ideas of the present invention are not limited thereto. Any modifications that utilize the ideas of the present invention will be included within the scope of protection of the patent rights of the present invention.

Claims

1. A cycloidal pinwheel reducer, comprising a housing (1), an input shaft (2), an output flange (3), and a cycloidal wheel (4); the input shaft (2) and the output flange (3) are coaxially arranged and rotatably mounted on the housing (1); the cycloidal wheel (4) is mounted on the input shaft (2) and eccentrically arranged relative to the input shaft (2), characterized in that: Also includes: A connecting shaft (41) is provided on the cycloidal wheel (4). There are multiple connecting shafts (41) and they are evenly distributed circumferentially on the cycloidal wheel (4). The first bushing (42) is sleeved on the connecting shaft (41); the housing (1) has a cycloidal profile curve (11) with a circular arc tooth shape at the position corresponding to the first bushing (42), and the first bushing (42) and the cycloidal profile curve (11) on the housing (1) fit together to form a rolling fit. The second bushing (43) is sleeved on the connecting shaft (41); the first bushing (42) and the second bushing (43) are located on the same side of the cycloidal wheel (4); There are multiple transmission holes (31), which are evenly distributed circumferentially on the output flange (3). The output flange (3) is inserted along the axial direction of the input shaft (2) and is located on the same side of the cycloidal wheel (4) with the first bushing (42) and the second bushing (43). The second bushing (43) is provided in each transmission hole (31). The second bushing (43) is eccentrically arranged relative to the transmission hole (31) and fits against the inner wall of the transmission hole (31) to form a rolling fit. A gap (44) is provided between the first bushing (42) and the connecting shaft (41), and between the second bushing (43) and the connecting shaft (41). The first bushing (42) and the connecting shaft (41) are concentrically arranged and rotatably arranged on the connecting shaft (41). The second bushing (43) and the connecting shaft (41) are concentrically arranged and rotatably arranged on the connecting shaft (41). A first bearing (5) is provided between the input shaft (2) and the cycloidal wheel (4), and the input shaft (2) has an eccentric part (21) at the first bearing (5).

2. The cycloidal pinwheel reducer according to claim 1, characterized in that... The first bushing (42) and the second bushing (43) are integrally formed from PEEK or steel materials.

3. A cycloidal pinwheel reducer according to claim 1, characterized in that... The wall thickness of the first bushing (42) and the second bushing (43) is 0.8mm-1.4mm.

4. A cycloidal pinwheel reducer according to claim 1, characterized in that... The housing (1) includes an outer shell (12) and a cover plate (13). The cover plate (13) covers the outside of the output flange (3) and is detachably connected to the cover plate (13). The first bushing (42) and the second bushing (43) are arranged facing the cover plate (13).

5. A cycloidal pinwheel reducer according to claim 1, characterized in that... The cycloidal wheel (4) is provided with a socket (45), and the output flange (3) is provided with a first mounting part (32) and a second mounting part (33). The first mounting part (32) is provided through the socket (45). A second bearing (6) is provided between the output flange (3) and the housing (1). There are two second bearings (6), which are respectively located on the outer walls of the first mounting part (32) and the second mounting part (33) and on the upper and lower sides of the cycloidal wheel (4).

6. A cycloidal pinwheel reducer according to claim 5, characterized in that... A third bearing (7) is provided between the input shaft (2) and the output flange (3). There are two third bearings (7), which are respectively located on the inner walls of the first mounting part (32) and the second mounting part (33) and on the upper and lower sides of the cycloidal wheel (4).

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