Planetary cycloid reducer, industrial robot

Abstract

The present invention provides a planetary cycloid pinwheel reducer and an industrial robot, belonging to the field of RV reducer design, comprising a first housing and an eccentric shaft. The first housing has a bearing tapered hole integrally formed thereon, and the first shaft end of the eccentric shaft has a bearing tapered surface integrally formed thereon. The bearing tapered surface is assembled in the bearing tapered hole, and a plurality of tapered rollers are sandwiched between the bearing tapered surface and the bearing tapered hole. The large diameter end of the tapered roller faces the eccentric portion of the eccentric shaft. On the one hand, the present invention improves the assembly efficiency of the entire machine; on the other hand, it avoids tilting and unbalanced loading of the eccentric shaft inside the reducer, improves the bending moment stiffness of the crankshaft system, and thereby enhances the load-bearing capacity of the tapered bearing; at the same time, it ensures that the crankshaft system can operate normally inside the reducer, thereby improving the operating stability and service life of the entire machine.

Description

Technical Field

[0001] The invention belongs to the field of RV reducer design, and in particular relates to a planetary cycloid pinwheel reducer and an industrial robot. Background Art

[0002] With the continued advancement of the manufacturing industry, industrial robots have been applied to various fields of industrial production, gradually replacing repetitive and high-risk tasks performed by humans. Industrial robot reducers, as key components, account for approximately one-third of the total production cost of industrial robots. As a key component of industrial robots, RV reducers (also known as planetary cycloid reducers) are gaining increasing attention. Reducers, serving as the "joints" of industrial robots, transmit and amplify power, playing a crucial role in the lifespan and accuracy of industrial robots. RV reducers utilize a cycloid planetary transmission system for high-precision control.

[0003] For existing reducers, their overall bending stiffness is primarily provided by the main bearing and tapered roller bearings. The tapered roller bearing, as the bearing supporting the eccentric shaft, primarily ensures the stiffness of the crankshaft system, ensuring a stable load on the cycloid wheel during operation and preventing unbalanced loading. The stiffness performance of the tapered roller bearing is primarily related to the design of the bearing's structural dimensions and the bearing's installation and fit. Its stiffness directly impacts the service life of the reducer's crankshaft system, and thus significantly affects the life of the entire machine. Therefore, design innovations in the tapered roller bearing's structure and installation are crucial to the prototype's stiffness and lifespan. In the traditional reducer structure, the installation and matching of the crankshaft tapered roller bearing mainly includes the crankshaft straight shaft section, the inner and outer rings of the tapered roller bearing, the retaining spring and the corresponding component bearing hole. The retaining spring is used to limit the axial displacement space of the crankshaft. This part of the structure has many parts and is complicated to install. At the same time, the separate assembly and matching of the inner and outer rings of the bearing are prone to deformation and errors, which causes the crankshaft to tilt and overload inside the reducer. When the RV reducer is under load impact, the deformation and axial displacement of the inner and outer rings of the tapered bearing can easily lead to loosening and axial movement of the eccentric shaft (crankshaft). Summary of the Invention

[0004] Therefore, the present invention provides a planetary cycloid pinwheel reducer and industrial robot, which can solve the technical problem that the tapered roller bearings in the existing RV reducer include independently designed and processed inner and outer rings, retaining springs, etc., have many parts and are complicated to install, and the separately assembled inner and outer rings of the bearings produce deformation and errors during assembly, resulting in tilting and unbalanced loading of the eccentric shaft.

[0005] In order to solve the above problems, the present invention provides a planetary cycloid pinwheel reducer, including a first shell and an eccentric shaft, the first shell having a bearing tapered hole integrally formed thereon, the first shaft end of the eccentric shaft having a bearing tapered surface integrally formed thereon, the bearing tapered surface assembled in the bearing tapered hole and a plurality of tapered rollers are clamped between the bearing tapered surface and the bearing tapered hole, the large diameter end of the tapered roller facing the eccentric portion of the eccentric shaft.

[0006] In some embodiments, a roller limiting flange is integrally formed on the end surface of the bearing conical surface on one side facing the eccentric portion.

[0007] In some embodiments, a roller limiting end plate is connected to the end surface of the first axial end of the eccentric shaft.

[0008] In some embodiments, the roller limiting end plate includes a plate body and a connecting column located on one side of the plate body, and the roller limiting end plate is threadedly connected to the end surface of the first shaft end through the connecting column.

[0009] In some embodiments, the diameter of the minor opening of the bearing tapered hole is d, the diameter of the plate is D, and 0.007 mm ≤ dD ≤ 0.029 mm.

[0010] In some embodiments, a force-applying structure is provided on the outer side of the plate.

[0011] In some embodiments, the planetary cycloid pinwheel reducer also includes a second housing having a bearing chamber for accommodating the second axial end of the eccentric shaft, the second axial end of the eccentric shaft is rotatably connected to the bearing chamber through a tapered roller bearing, and a retaining spring is provided adjacent to the outer end surface of the bearing outer ring of the tapered roller bearing, and the retaining spring is assembled in the outer port of the bearing chamber to form an axial limit for the eccentric shaft.

[0012] In some embodiments, the first housing is one of a planet carrier and a rigid disk, and the second housing is the other of the planet carrier and the rigid disk.

[0013] The present invention also provides an industrial robot comprising the above-mentioned planetary cycloid pinwheel reducer.

[0014] The present invention provides a planetary cycloid pinwheel reducer and industrial robot, in which the tapered hole of the bearing serves as the outer ring of the bearing, and the tapered surface of the bearing serves as the inner ring of the bearing, and the two clamp the tapered roller. That is, the technical solution integrates the bearing inner ring and outer ring that are independently assembled in the prior art into a first shell and an eccentric shaft, respectively. On the one hand, it reduces the number of assembled parts, simplifies the assembly, and improves the assembly efficiency of the whole machine; on the other hand, since the inner and outer rings of the bearing are no longer assembled separately, the deformation and error of the installation fit when the inner and outer rings of the bearing are assembled separately are eliminated, and the tilting and unbalanced loading of the eccentric shaft inside the reducer are avoided, the bending moment stiffness of the crankshaft system is improved, and the load-bearing capacity of the tapered bearing is enhanced; at the same time, the one-piece molded bearing inner and outer rings of the present invention can also avoid the deformation and displacement of the tapered inner and outer rings under load impact, which causes the eccentric shaft to loosen and axially move inside the reducer, ensuring that the crankshaft system can operate normally inside the reducer, thereby improving the operating stability and life of the whole machine. In addition, the tapered rollers in the present invention exist independently of the bearing tapered surface and the bearing tapered hole, and their number and size can be changed to meet different load-bearing requirements, thereby improving the versatility of the reducer. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Schematic diagram of the internal cross-sectional structure of a planetary cycloid pinwheel reducer according to an embodiment of the present invention;

[0016] Figure 2 for Figure 1 A magnified schematic diagram of a local location.

[0017] The reference numerals indicate:

[0018] 1. First housing; 11. Bearing tapered hole; 2. Eccentric shaft; 21. Bearing tapered surface; 22. Roller limiting flange; 23. Roller limiting end plate; 231. Plate body; 232. Connecting column; 233. Force-applying structure; 3. Tapered roller; 4. Second housing; 41. Bearing chamber; 5. Tapered roller bearing; 51. Circlip; 100. Pinion housing; 101. Main bearing; 102. Planetary gear; 103. Sealing ring; 104. Needle roller bearing; 105. Cycloid wheel. DETAILED DESCRIPTION

[0019] See also Figures 1 to 2As shown, according to an embodiment of the present invention, a planetary cycloid pinwheel reducer, also known as an RV reducer, is provided, including a first housing 1 and an eccentric shaft 2. The first housing 1 has a bearing tapered hole 11 integrally formed thereon, and the first shaft end of the eccentric shaft 2 has a bearing tapered surface 21 integrally formed thereon. The bearing tapered surface 21 is assembled in the bearing tapered hole 11 and a plurality of tapered rollers 3 are clamped between the bearing tapered surface 21 and the bearing tapered hole 11. The large diameter end of the tapered roller 3 faces the eccentric portion of the eccentric shaft 2. It can be understood that the small diameter end of the tapered roller 3 faces the eccentric shaft 2 and is on the outside of the bearing tapered hole 11. In this technical solution, the bearing tapered hole 11 acts as the bearing outer ring, and the bearing tapered surface 21 acts as the bearing inner ring, and the two clamp the tapered roller 3. That is, this technical solution integrally forms the bearing inner ring and outer ring that are independently assembled in the prior art on the first shell 1 and the eccentric shaft 2. On the one hand, it reduces the number of assembled parts, simplifies the assembly, and improves the assembly efficiency of the whole machine; on the other hand, since the bearing inner and outer rings are no longer assembled separately, the deformation and error of the installation fit when the bearing inner and outer rings are assembled separately are eliminated, and the eccentric shaft 2 is avoided from tilting and unbalanced loading inside the reducer, thereby improving the bending moment stiffness of the crankshaft system and enhancing the load-bearing capacity of the tapered bearing; at the same time, the integrally formed bearing inner and outer rings of the present invention can also avoid the deformation and displacement of the tapered inner and outer rings under load impact, which leads to the problem of loosening and axial movement of the eccentric shaft inside the reducer, ensuring that the crankshaft system can operate normally inside the reducer, thereby improving the operation stability and life of the whole machine. Furthermore, the tapered rollers 3 of the present invention exist independently of the bearing tapered surface 21 and the bearing tapered bore 11, and their number and size can be adjusted to meet different load-bearing requirements, thereby improving the versatility (versatility) of the reducer. It should be noted that the reducer formed by the technical solution of the present invention can withstand greater overturning moments, reducing the radial movement of the eccentric shaft 2 within the reducer, thereby ensuring the smooth operation of the cycloid gear within the reducer and improving the rigidity and lifespan of the planetary cycloid reducer.

[0020] Specifically, in the planetary cycloid pinwheel reducer in the prior art, the original structure of the rigid disk is to use a retaining ring groove and a retaining ring to limit and pre-tighten the eccentric shaft assembly. The known structure requires the installation of three tapered bearing outer rings and three retaining rings at the planetary carrier end. At the same time, the retaining rings need to be processed separately to ensure a certain thickness to ensure the pre-tightening of the crankshaft assembly. At the same time, the tapered bearing inner ring also needs to be installed on the eccentric shaft. The technical solution of the present invention is as follows: Figure 1 As shown, the bearing outer ring and the planet carrier disc are combined into one. During assembly, there is no need to install the bearing inner and outer rings and the retaining ring. The function of the original structure can be completed, the assembly process is omitted, and the assembly efficiency is improved.

[0021] In order to ensure that the eccentric shaft assembly has sufficient bending moment stiffness, the known eccentric shaft structure needs to process retaining springs of different sizes at both ends of the eccentric shaft according to the size of the parts to position and pre-tighten the eccentric shaft bearing to ensure stiffness. This method uses a large number of parts and the installation process is complicated. In addition, the outer ring of the tapered bearing will be deformed during the installation process, resulting in radial movement of the eccentric shaft during the operation of the reducer. The eccentric shaft and the planetary carrier bearing hole are designed to be a conical surface structure, which avoids the deformation problem of the tapered outer ring. At the same time, it can greatly reduce the number of parts, reduce the assembly process, and greatly reduce the difficulty of installation. While improving the assembly efficiency, the stiffness and reliability of the whole machine are also significantly improved.

[0022] See also Figure 1 As shown, the eccentric shaft 2 comprises a straight shaft section and an eccentric portion. In a preferred embodiment, a roller stop flange 22 is integrally formed on the end surface of the bearing conical surface 21 facing the eccentric portion, thereby limiting the large-diameter end of the circumferential roller toward the small-diameter end. The integral formation of the roller stop flange 22 further reduces the number of assembled parts and improves assembly efficiency. During the actual assembly process, it is only necessary to first place multiple tapered rollers 3 within the bearing tapered bore 11 and then insert the eccentric shaft 2 from the large-diameter side to the small-diameter side of the bearing tapered bore 11. The dimensional characteristics of the tapered rollers 3 are then utilized to limit the eccentric shaft 2 in one axial direction, making assembly extremely simple and convenient.

[0023] See also Figure 2 As shown, a roller limiting end plate 23 is connected to the end face of the first axial end of the eccentric shaft 2. When the eccentric shaft 2 produces axial movement, the roller limiting end plate 23 can drive the multiple tapered rollers 3 on one side thereof to move in the direction of movement, thereby ensuring the smoothness of rotation and the supporting stiffness.

[0024] In a specific embodiment, the roller limiting end plate 23 includes a plate body 231 and a connecting column 232 on one side of the plate body 231. The roller limiting end plate 23 is threadedly connected to the end face of the first shaft end through the connecting column 232, and a reliable and convenient connection of the roller limiting end plate 23 is achieved by screwing. In a preferred embodiment, a force-applying structure 233 is provided on the outer side surface (also referred to as the outer end face) of the plate body 231, and the roller limiting end plate 23 can be easily screwed and installed and removed through the force-applying structure 233. The aforementioned force-applying structure 233 can be, for example, a hexagonal groove. Of course, in some working conditions, the roller limiting end plate 23 can also be connected to the eccentric shaft 2 by a snap-fit ​​connection.

[0025] The aforementioned roller limiting end plate 23 can also be used to prevent leakage of lubricating grease at the tapered roller 3. For this purpose, the small diameter of the bearing tapered hole 11 is d, the diameter of the plate body 231 is D, 0.007mm≤dD≤0.029mm.

[0026] Continue to see Figure 1 As shown, the planetary cycloid pinwheel reducer also includes a second housing 4, which has a bearing chamber 41 for accommodating the second axial end of the eccentric shaft 2. The second axial end of the eccentric shaft 2 is rotatably connected to the bearing chamber 41 through a tapered roller bearing 5, and a retaining spring 51 is provided adjacent to the outer end surface of the bearing outer ring of the tapered roller bearing 5. The retaining spring 51 is assembled in the outer port of the bearing chamber 41 to form an axial limit for the eccentric shaft 2. That is, in this technical solution, the axial displacement of the eccentric shaft 2 is limited by the retaining spring 51 and the shape of the tapered roller 3, which is simple to assemble and easy to implement.

[0027] Specifically, the first housing 1 is one of the planet carrier and the rigid disk, and the second housing 4 is the other of the planet carrier and the rigid disk. Figure 1 As shown, the first housing 1 is a planetary carrier, and the second housing 4 is a rigid disk. The RV reducer also includes a pinion housing 100, a main bearing 101, planetary gears 102, a sealing ring 103, a needle roller bearing 104 and a cycloid wheel 105.

[0028] According to an embodiment of the present invention, there is further provided an industrial robot comprising the above-mentioned planetary cycloid pinwheel reducer.

[0029] It is easy for those skilled in the art to understand that, under the premise of no conflict, the advantageous technical features of the above-mentioned methods can be freely combined and superimposed.

[0030] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention. The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art may make various improvements and variations without departing from the technical principles of the present invention, and such improvements and variations shall also be considered within the scope of protection of the present invention.

Claims

1. A planetary cycloid pinwheel reducer, comprising a first housing (1) and an eccentric shaft (2), characterized in that: The first housing (1) has a bearing conical hole (11) integrally formed thereon, the first axial end of the eccentric shaft (2) has a bearing conical surface (21) integrally formed thereon, the bearing conical surface (21) is assembled in the bearing conical hole (11), and a plurality of tapered rollers (3) are clamped between the bearing conical surface (21) and the bearing conical hole (11), the large diameter end of the tapered roller (3) facing the eccentric portion of the eccentric shaft (2); a roller limiting flange (22) is integrally formed on the end face of the bearing conical surface (21) facing the eccentric portion; and a roller limiting end plate (23) is connected to the end face of the first axial end of the eccentric shaft (2).

2. The planetary cycloid pinwheel reducer according to claim 1, characterized in that: The roller limiting end plate (23) comprises a plate body (231) and a connecting column (232) located on one side of the plate body (231); the roller limiting end plate (23) is threadedly connected to the end surface of the first shaft end via the connecting column (232).

3. The planetary cycloid pinwheel reducer according to claim 2, characterized in that: The diameter of the small-diameter opening of the bearing tapered hole (11) is d, and the diameter of the plate body (231) is D, where 0.007 mm ≤ dD ≤ 0.029 mm.

4. The planetary cycloid pinwheel reducer according to claim 2, characterized in that: The outer surface of the plate body (231) is provided with a force-applying structure (233).

5. The planetary cycloid pinwheel reducer according to claim 1, characterized in that: The invention also includes a second housing (4), wherein the second housing (4) has a bearing chamber (41) for accommodating the second axial end of the eccentric shaft (2), the second axial end of the eccentric shaft (2) is rotatably connected to the bearing chamber (41) through a tapered roller bearing (5), and a retaining spring (51) is provided adjacent to the outer end surface of the bearing outer ring of the tapered roller bearing (5), and the retaining spring (51) is assembled in the outer port of the bearing chamber (41) to form an axial limit for the eccentric shaft (2).

6. The planetary cycloid pinwheel reducer according to claim 5, characterized in that: The first housing (1) is one of a planet carrier and a rigid disk, and the second housing (4) is the other of the planet carrier and the rigid disk.

7. An industrial robot, characterized in that: A planetary cycloid pinwheel reducer comprising the planetary cycloid pinwheel reducer according to any one of claims 1 to 5.

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