A two-stage reducer based on inner and outer cycloid

Abstract

This invention provides a two-stage reducer based on cycloidal and epicycloidal transmissions, belonging to the field of reducer technology. The two-stage reducer includes a housing, a primary input mechanism, a primary reduction mechanism, a primary output / secondary input mechanism, a secondary reduction mechanism, and a secondary output mechanism. The primary and secondary reduction mechanisms employ either epicycloidal pinwheel transmission or cycloidal pinwheel transmission, and the transmission types are different. Both the primary and secondary reduction mechanisms include at least one cycloidal wheel, at least three eccentric crankshafts with pins evenly distributed along the circumference, and an intermediate fixing plate for fixing the eccentric crankshafts. Both the primary output / secondary input mechanism and the secondary output mechanism include pinwheels. Under the same reduction ratio, this invention exhibits good dynamic characteristics, a compact and simple structure, and the pinwheels can be designed with a sufficiently large diameter, thus improving load-bearing capacity. Furthermore, the pinwheels are fixed at both ends by bearings and can roll, reducing wear between components.

Description

Technical Field

[0001] This invention belongs to the field of speed reducer technology, and particularly relates to a two-stage speed reducer based on an internal cycloid and an external cycloid. Background Technology

[0002] The cycloidal pinwheel reducer is a novel transmission device that applies the planetary transmission principle and uses cycloidal pin gear meshing. The entire transmission device of the cycloidal pinwheel reducer can be divided into three parts: the input section, the reduction section, and the output section. According to the number of reduction cycles, reducers can be classified as single-stage reducers and multi-stage reducers.

[0003] However, in the existing technology, the speed reduction part of the cycloidal reducer has sliding friction between the components, resulting in high wear between the components. In order to achieve a high reduction ratio, the pin wheel density is large and the pin wheel diameter is small, resulting in insufficient load-bearing capacity. Summary of the Invention

[0004] The purpose of this invention is to overcome the aforementioned defects and deficiencies and provide a two-stage reducer based on cycloid and epicycloid. Under the same reduction ratio, this invention has good dynamic characteristics, a compact and simple structure, and the pin wheel can be designed to have a sufficiently large diameter, thus improving the load-bearing capacity. Moreover, the two ends of the pin wheel are fixed by bearings and can roll on their own, reducing wear between parts.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows: A two-stage reducer based on cycloid and exocycloid, comprising a housing, a first-stage input mechanism, a first-stage reduction mechanism, a first-stage output mechanism that also serves as a second-stage input mechanism, a second-stage reduction mechanism, and a second-stage output mechanism; The first-stage reduction mechanism and the second-stage reduction mechanism respectively adopt one of external cycloidal pinwheel drive and internal cycloidal pinwheel drive, and the two have different transmission types; Both the first-stage reduction mechanism and the second-stage reduction mechanism include at least one cycloidal wheel, at least three eccentric crankshafts with pins evenly distributed along the circumferential direction, and an intermediate fixing plate for fixing the eccentric crankshafts with pins. The two ends of the eccentric crankshafts with pins are respectively supported on the outer shell and the intermediate fixing plate by bearings, and the eccentric section of the eccentric crankshafts with pins supports the cycloidal wheel by bearings. The primary output and secondary input mechanism and the secondary output mechanism both include a pin wheel. The two ends of the pin wheel are fixed to the corresponding output components by bearings. The pin wheel meshes with the cycloidal wheel of the corresponding stage to achieve speed reduction transmission. The primary input mechanism is driven by the cycloidal wheel of the primary reduction mechanism, the primary output and secondary input mechanism is driven by the pin wheel of the primary reduction mechanism and the cycloidal wheel of the secondary reduction mechanism respectively, and the secondary output mechanism is driven by the pin wheel of the secondary reduction mechanism. Both the primary input mechanism and the secondary output mechanism adopt a two-end support structure with no cantilever output.

[0006] As a further embodiment of the present invention, the primary input mechanism is a shaft input mechanism, and the secondary output mechanism is a shaft output mechanism; The shaft input mechanism includes an input shaft, one end of which is supported on the left outer casing by a bearing, and the other end of which is supported on the left inner ring of the output shaft of the shaft output mechanism by a bearing. The first-stage reduction mechanism adopts an external cycloidal pinwheel drive, including two external cycloidal wheels, the centers of which are respectively connected to the double eccentric section of the input shaft through bearings; The primary output and secondary input mechanism includes a primary pin wheel and an outer cylinder. The two ends of the primary pin wheel are evenly fixed to the left circumference of the outer cylinder by bearings. The outer cylinder is supported on the inner circumference of the left outer shell by bearings. The secondary reduction mechanism adopts an internal cycloidal pinwheel drive, including two internal cycloidal wheels, which are respectively connected to the double eccentric holes on the right side of the outer cylinder through bearings; The shaft output mechanism includes a secondary pinwheel and an output shaft. The two ends of the secondary pinwheel are evenly fixed to the outer circumference of the output shaft by bearings. One end of the output shaft is supported by a bearing on the right outer shell, and the other end is supported by a bearing on the inner ring of the intermediate fixed plate.

[0007] As a further embodiment of the present invention, the first-stage reduction mechanism using an epicycloidal pinwheel drive further includes three or more circumferentially distributed first-stage pin eccentric crankshafts. The epicycloidal wheel is supported by bearings on the two eccentric sections of the first-stage pin eccentric crankshafts. The two ends of the first-stage pin eccentric crankshafts are respectively fixed to the outer shell and the intermediate fixed plate by bearings. The intermediate fixed plate is fixed to the outer shells at both ends by a first-stage support rod and a second-stage support rod.

[0008] As a further embodiment of the present invention, the secondary reduction mechanism using an internal cycloidal pinwheel drive further includes three or more secondary pin eccentric crankshafts evenly distributed in the circumferential direction. The internal cycloidal wheel is supported by bearings on the two eccentric sections of the secondary pin eccentric crankshafts, and the two ends of the secondary pin eccentric crankshafts are respectively fixed to the outer shell and the intermediate fixed plate by bearings.

[0009] As a further embodiment of the present invention, the primary input mechanism is a flange input mechanism, and the secondary output mechanism is a flange output mechanism; The flange input mechanism includes an input flange, which is supported on the left side housing by a bearing. The first-stage reduction mechanism adopts an internal cycloidal pinwheel drive, including two internal cycloidal wheels, which are respectively connected to the double eccentric holes of the input flange through bearings; The primary output and secondary input mechanism includes a primary pinwheel and a central shaft. The two ends of the primary pinwheel are evenly fixed to the outer circumference of the left side of the central shaft by bearings. The two ends of the central shaft are respectively supported by bearings on the left and right outer shells. The secondary reduction mechanism adopts an external cycloidal pinwheel drive, including two external cycloidal wheels, the centers of which are respectively connected to the double eccentric section of the central shaft through bearings; The flange output mechanism includes a secondary pinwheel and an output flange. The two ends of the secondary pinwheel are evenly fixed to the inner circumference of the output flange by bearings, and the output flange is supported by the right outer shell by bearings.

[0010] As a further embodiment of the present invention, the first-stage reduction mechanism using an internal cycloidal pinwheel drive further includes three or more circumferentially distributed first-stage pin eccentric crankshafts. The internal cycloidal wheel is supported by bearings on the two eccentric sections of the first-stage pin eccentric crankshafts, and the two ends of the first-stage pin eccentric crankshafts are respectively fixed to the left outer shell and the middle fixed plate by bearings.

[0011] As a further embodiment of the present invention, the secondary reduction mechanism using an epicycloidal pinwheel drive further includes three or more circumferentially distributed secondary pin eccentric crankshafts. The epicycloidal wheel is supported by bearings on the two eccentric sections of the secondary pin eccentric crankshafts. The two ends of the secondary pin eccentric crankshafts are respectively fixed to the outer shell and the intermediate fixed plate by bearings. The intermediate fixed plate is fixed to the outer shells at both ends by support rods.

[0012] As a further aspect of the present invention, the phase difference between the two eccentric portions of the double eccentric section of the input shaft, the double eccentric hole of the input flange, the double eccentric hole of the outer cylinder, and the two eccentric portions of the double eccentric section of the central shaft is 180 degrees.

[0013] As a further embodiment of the present invention, the shaft extension end of the input shaft is a double eccentric segment with a phase difference of 180 degrees, and the double eccentric segment is supported and connected to the first outer cycloidal wheel and the second outer cycloidal wheel respectively through bearings; the phase difference between the two eccentric holes of the inner cycloidal disk fixed by the input flange is 180 degrees, and the two eccentric holes are supported and connected to the first inner cycloidal wheel and the second inner cycloidal wheel respectively through bearings; the phase difference between the two eccentric holes of the inner cycloidal disk fixed on the outer cylinder is 180 degrees, and the two eccentric holes are supported and connected to the first inner cycloidal wheel and the second inner cycloidal wheel respectively through bearings; the shaft extension end of the central shaft is a double eccentric segment with a phase difference of 180 degrees, and the double eccentric segment is supported and connected to the first outer cycloidal wheel and the second outer cycloidal wheel respectively through bearings.

[0014] As a further embodiment of the present invention, the eccentric crankshaft with pin has two eccentric sections with a phase difference of 180 degrees, and the two eccentric sections support two cycloidal wheels respectively through bearings.

[0015] As a further embodiment of the present invention, the phase difference between the two eccentric sections of the first-stage pin eccentric crankshaft is 180 degrees; wherein, when the first-stage reduction mechanism is a shaft input, the two eccentric sections are supported and connected to the first and second external cycloidal wheels respectively through bearings; when the first-stage reduction mechanism is a flange input, the two eccentric sections are supported and connected to the first and second internal cycloidal wheels respectively through bearings.

[0016] As a further embodiment of the present invention, the phase difference between the two eccentric sections of the secondary pin eccentric crankshaft is 180 degrees; wherein, when the secondary reduction mechanism is a shaft input, the two eccentric sections are supported and connected to the first and second epicycloid wheels respectively through bearings; when the secondary reduction mechanism is a flange input, the two eccentric sections are supported and connected to the first and second epicycloid wheels respectively through bearings.

[0017] As a further embodiment of the present invention, the intermediate fixing plate is fixed to both ends of the outer shell by at least two support rods, and remains relatively stationary with respect to the outer shell.

[0018] As a further embodiment of the present invention, in each stage of the reduction mechanism, the number of teeth of the cycloidal wheel differs from the number of teeth of the pin wheel by 1, forming a tooth difference planetary transmission mechanism.

[0019] As a further embodiment of the present invention, the reduction ratio of the first-stage reduction mechanism and the reduction ratio of the second-stage reduction mechanism are both 10-30, and the total reduction ratio is 100-900, preferably 100-300.

[0020] As a further embodiment of the present invention, the secondary reduction mechanism in the shaft input form has the same structure as the primary reduction mechanism in the flange input form, both of which have a cycloidal wheel connected to the eccentric hole of the outer cylinder through a bearing; the primary reduction mechanism in the shaft input form has the same structure as the secondary reduction mechanism in the flange input form, both of which have a cycloidal wheel connected to the eccentric section of the central shaft through a bearing, thereby realizing modular interchangeability of the core reduction mechanism.

[0021] As a further embodiment of the present invention, the bearings between the needle wheel and the output component, the bearings between the eccentric crankshaft and the cycloidal wheel, the bearings between the input shaft and the outer cycloidal wheel, and the bearings between the outer cylinder and the inner cycloidal wheel are all rolling bearings; the output component is the left circumference of the outer cylinder used to fix both ends of the first-stage needle wheel, or the left outer circumference of the central shaft.

[0022] As a further aspect of the present invention, the bearing provided at the double eccentric holes of the outer cylinder is a multi-ball rolling bearing, wherein the load borne by a single ball is less than the load of a single ball of the bearing at the eccentric crankshaft.

[0023] Compared with the prior art, the two-stage reducer based on cycloid and epicycloid provided in this application has the following advantages: 1. The two-stage reducer based on internal and external cycloidal gears provided by this invention employs a series transmission of two cycloidal pinwheels. The total reduction ratio is the product of the first-stage and second-stage reduction ratios. By matching cycloidal wheels and pinwheels with different numbers of teeth, a wide range of reduction ratios from 100 to 900 can be easily achieved. It is particularly suitable for the 100-300 reduction ratio range most commonly used in industrial fields, meeting requirements without the need for a three-stage transmission. Compared to traditional two-stage cycloidal reducers with the same reduction ratio, this invention features a compact structure due to its two-stage reduction, reducing the number of pinwheels required, eliminating the intermediate transition connection structure, shortening the overall axial length of the machine, and reducing the pressure on lubrication and heat dissipation, making it suitable for installation scenarios with limited space.

[0024] 2. The two-stage reducer based on internal and external cycloids provided by this invention adopts a pinwheel fixed structure with bearings at both ends, allowing the pinwheel itself to roll freely. This transforms the sliding engagement between the cycloidal wheel and the pinwheel in traditional cycloidal transmission into pure rolling engagement, reducing friction loss. Furthermore, rolling bearings are used to support the eccentric crankshaft between the pin and the cycloidal wheel, the input shaft between the input shaft and the external cycloidal wheel, and the outer cylinder between the internal cycloidal wheel. This improves the overall transmission efficiency, significantly reduces tooth surface wear and contact fatigue due to rolling friction, reduces wear between components, extends the service life of components, and reduces equipment maintenance frequency and costs.

[0025] 3. The two-stage reducer based on cycloids and epicycloids provided by this invention significantly reduces the number of pinwheels, allowing for a larger pinwheel diameter within the same radial space. This significantly increases the meshing contact area between the pinwheels and the cycloid wheels, reducing contact stress. The use of three or more circumferentially distributed eccentric crankshafts with pins evenly distributed across the circumference distributes the load evenly to multiple support points, preventing single-point overload. Simultaneously, the symmetrical arrangement of the double cycloid wheels further distributes the transmission load, enhancing the overall impact resistance. The outer cylinder and central shaft, serving as intermediate components of the two-stage transmission, employ an integral structural design, exhibiting high rigidity and strength, and capable of withstanding greater torque loads.

[0026] 4. The two-stage reducer based on internal and external cycloids provided by this invention reduces the number of pinwheels, thereby reducing the number of meshing points and the total amount of frictional heat generation. Simultaneously, the heat generation power of rolling friction is far lower than that of sliding friction, resulting in a lower overall temperature rise. The eccentric bore of the outer cylinder uses multi-ball bearings, where each ball bears a smaller load and has a larger heat dissipation area, effectively solving the problem of poor heat dissipation of eccentric bearings in traditional cycloid reducers. Although the bearing at the pin-eccentric crankshaft has fewer balls, the distributed total load still maintains good heat dissipation. The double eccentric section of the input shaft, the double eccentric bore of the outer cylinder, and the double eccentric section of the pin-eccentric crankshaft all adopt a 180-degree phase difference design, combined with symmetrically arranged double cycloid wheels, which can completely balance rotational inertia and inertial torque, resulting in smooth operation and significantly reduced vibration and noise. Both input and output components have a structure with fixed ends, eliminating the need for cantilever output and ensuring stable transmission accuracy without long-term accuracy drift. Attached Figure Description

[0027] Figure 1 This is a schematic cross-sectional view of the overall structure of a two-stage reducer based on an introcycloid and an extrocycloid, provided in Embodiment 1 of the present invention.

[0028] Figure 2 This is a schematic cross-sectional view of the overall structure of a two-stage reducer based on an introcycloid and an extrocycloid, provided in Embodiment 2 of the present invention.

[0029] Figure 3 This is a schematic cross-sectional view of the cycloidal deceleration mechanism in a two-stage reducer based on an incycloidal and an exocycloidal structure, provided in Embodiment 1 of the present invention.

[0030] Figure 4 This is a cross-sectional schematic diagram of the inner cycloidal deceleration mechanism in a two-stage reducer based on inner and outer cycloidal components, provided in Embodiment 1 of the present invention.

[0031] Figure 5 This is a schematic cross-sectional view of the outer cylinder and inner cycloidal disk structure in a two-stage reducer based on an inner and outer cycloidal axis provided by the present invention.

[0032] Figure 6 This is a cross-sectional schematic diagram of the fixed connection between the intermediate fixed plate and the outer shell of a two-stage reducer based on an inner cycloid and an outer cycloid, as provided in Embodiment 1 of the present invention.

[0033] Figure 7 This is a cross-sectional schematic diagram of the fixed connection between the intermediate fixed plate and the outer shell of a two-stage reducer based on an inner cycloid and an outer cycloid, provided in Embodiment 2 of the present invention.

[0034] Explanation of reference numerals in the attached figures: 1-First-stage pinwheel, 2-First-stage support rod, 3-Input shaft, 4-Left side housing, 5-First-stage eccentric crankshaft with pin, 6-Outer cylinder, 7-First external cycloidal wheel, 8-Second external cycloidal wheel, 9-First internal cycloidal wheel, 10-Second internal cycloidal wheel, 11-Right side housing, 12-Second-stage eccentric crankshaft with pin, 13-Second-stage pinwheel, 14-Output shaft, 15-Second-stage support rod, 16-Intermediate fixed plate, 17-Rotating shaft, 18-Output flange, 19-Input flange. Detailed Implementation

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein in the specification of the application is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms "comprising" and "having," and any variations thereof, in the specification, claims, and foregoing drawings of this application are intended to cover non-exclusive inclusion. The terms "first," "second," etc., in the specification, claims, or foregoing drawings of this application are used to distinguish different objects, not to describe a particular order.

[0036] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0037] To address the issues of sliding friction and high wear between components in the reduction section of existing cycloidal reducers, which require high pin wheel density and small diameter to achieve a high reduction ratio, resulting in insufficient load-bearing capacity, this invention provides a two-stage reducer based on internal and external cycloidal components. At the same reduction ratio, this invention exhibits excellent dynamic characteristics, a compact and simple structure, and allows for a sufficiently large pin wheel diameter, thus improving load-bearing capacity. Furthermore, the pin wheels are fixed at both ends by bearings and can roll independently, reducing wear between components.

[0038] See Figures 1 to 7As shown, this invention relates to a two-stage reducer based on cycloidal and epicycloidal transmissions, comprising a housing, a primary input mechanism, a primary reduction mechanism, a primary output / secondary input mechanism, a secondary reduction mechanism, and a secondary output mechanism. The primary and secondary reduction mechanisms employ either epicycloidal pinwheel transmission or epicycloidal pinwheel transmission, and their transmission types are different. Both the primary and secondary reduction mechanisms include at least one cycloidal wheel, at least three eccentric crankshafts with pins evenly distributed along the circumference, and an intermediate fixed plate 16 for fixing the eccentric crankshafts. The two ends of the eccentric crankshafts are supported by bearings on the outer casing and the intermediate fixed plate 16, respectively. The eccentric section of the eccentric crankshaft supports the cycloidal wheel via bearings. Both the primary output / secondary input mechanism and the secondary output mechanism include pin wheels. The two ends of the pin wheels are fixed by bearings to the corresponding output components. The pin wheels mesh with the corresponding cycloidal wheels to achieve speed reduction. The primary input mechanism is driven by the cycloidal wheel of the primary reduction mechanism. The primary output / secondary input mechanism is driven by the pin wheels of the primary reduction mechanism and the cycloidal wheels of the secondary reduction mechanism. The secondary output mechanism is driven by the pin wheels of the secondary reduction mechanism. Both the primary input mechanism and the secondary output mechanism adopt a two-end support structure with no cantilever output.

[0039] In this invention, when the primary input mechanism is a shaft input mechanism, the secondary output mechanism is a shaft output mechanism. The shaft input mechanism includes an input shaft 3, one end of which is supported by a bearing on the left outer casing 4, and the other end is supported by a bearing on the left inner ring of the output shaft 14 of the shaft output mechanism. The primary reduction mechanism employs an epicycloidal pinwheel drive and includes two epicycloidal wheels. The centers of the two epicycloidal wheels are respectively connected to the double eccentric sections of the input shaft 3 via bearings. The primary reduction mechanism employing epicycloidal pinwheel drive also includes three or more circumferentially distributed primary pin-shaped eccentric crankshafts 5. The epicycloidal wheels are supported by bearings on the two eccentric sections of the primary pin-shaped eccentric crankshafts 5. Both ends of the primary pin-shaped eccentric crankshafts 5 are respectively fixed to the outer casing and the intermediate fixed plate 16 by bearings. The intermediate fixed plate 16 is fixed to the outer casing at both ends by primary support rods 2 and secondary support rods 15.

[0040] The primary output and secondary input mechanism includes a primary pinwheel 1 and an outer cylinder 6. The two ends of the primary pinwheel 1 are evenly fixed to the left circumference of the outer cylinder 6 by bearings. The outer cylinder 6 is supported on the inner circumference of the left outer shell 4 by bearings. The secondary reduction mechanism adopts an internal cycloidal pinwheel drive and includes two internal cycloidal wheels. The two internal cycloidal wheels are respectively connected to the double eccentric holes on the right side of the outer cylinder 6 by bearings. The secondary reduction mechanism using internal cycloidal pinwheel drive also includes three or more secondary pin eccentric crankshafts 12 evenly distributed in the circumferential direction. The internal cycloidal wheels are supported on the two eccentric sections of the secondary pin eccentric crankshafts 12 by bearings. The two ends of the secondary pin eccentric crankshafts 12 are respectively fixed to the outer shell and the intermediate fixed plate 16 by bearings.

[0041] The shaft output mechanism includes a secondary pinwheel 13 and an output shaft 14. The two ends of the secondary pinwheel 13 are evenly fixed to the outer circumference of the output shaft 14 by bearings. One end of the output shaft 14 is supported by a bearing on the right outer casing 11, and the other end is supported by a bearing on the inner ring of the intermediate fixed plate 16.

[0042] In this invention, when the primary input mechanism is a flange input mechanism, the secondary output mechanism is a flange output mechanism. The flange input mechanism includes an input flange 19, which is supported on the left outer shell 4 by bearings. The primary reduction mechanism adopts an internal cycloidal pinwheel drive and includes two internal cycloidal wheels, which are respectively connected to the double eccentric holes of the input flange 19 by bearings. The primary reduction mechanism using internal cycloidal pinwheel drive also includes three or more circumferentially distributed primary pin eccentric crankshafts 5. The internal cycloidal wheels are supported on the two eccentric sections of the primary pin eccentric crankshafts 5 by bearings, and the two ends of the primary pin eccentric crankshafts 5 are respectively fixed to the left outer shell 4 and the intermediate fixed plate 16 by bearings.

[0043] The primary output and secondary input mechanism includes a primary pinwheel 1 and a central shaft. The two ends of the primary pinwheel 1 are evenly fixed to the outer circumference of the left side of the central shaft by bearings. The two ends of the central shaft are respectively supported by bearings on the left outer shell 4 and the right outer shell 11. The secondary reduction mechanism adopts an epicycloidal pinwheel drive and includes two epicycloidal wheels. The centers of the two epicycloidal wheels are respectively connected to the double eccentric section of the central shaft by bearings. The secondary reduction mechanism using epicycloidal pinwheel drive also includes three or more circumferentially distributed secondary pin eccentric crankshafts 12. The epicycloidal wheels are supported by bearings on the two eccentric sections of the secondary pin eccentric crankshafts 12. The two ends of the secondary pin eccentric crankshafts 12 are respectively fixed to the outer shell and the intermediate fixed plate 16 by bearings. The intermediate fixed plate 16 is fixed to the outer shells at both ends by support rods.

[0044] The flange output mechanism includes a secondary pinwheel 13 and an output flange 18. The two ends of the secondary pinwheel 13 are evenly fixed to the inner circumference of the output flange 18 by bearings. The output flange 18 is supported by the right outer shell 11 by bearings.

[0045] In this invention, the phase difference between the two eccentric portions of the double eccentric section of the input shaft 3, the double eccentric hole of the input flange 19, the double eccentric hole of the outer cylinder 6, and the double eccentric section of the central shaft is 180 degrees. Specifically: the shaft extension end of the input shaft 3 is a double eccentric section with a phase difference of 180 degrees, and the double eccentric section is supported and connected to the first outer cycloidal wheel 7 and the second outer cycloidal wheel 8 respectively by bearings; the phase difference between the two eccentric holes of the input flange 19 fixing the inner cycloidal disk is 180 degrees, and the two eccentric holes are supported and connected to the first inner cycloidal wheel 9 and the second inner cycloidal wheel 10 respectively by bearings; the phase difference between the two eccentric holes of the outer cylinder 6 fixing the inner cycloidal disk is 180 degrees, and the two eccentric holes are supported and connected to the first inner cycloidal wheel 9 and the second inner cycloidal wheel 10 respectively by bearings; the shaft extension end of the central shaft is a double eccentric section with a phase difference of 180 degrees, and the double eccentric section is supported and connected to the first outer cycloidal wheel 7 and the second outer cycloidal wheel 8 respectively by bearings.

[0046] In this invention, the pin-driven eccentric crankshaft has two eccentric sections with a phase difference of 180 degrees. Each eccentric section supports two cycloidal wheels via bearings. Specifically, the two eccentric sections of the first-stage pin-driven eccentric crankshaft 5 have a phase difference of 180 degrees. When the first-stage reduction mechanism is a shaft input, the two eccentric sections are supported and connected to the first outer cycloidal wheel 7 and the second outer cycloidal wheel 8 via bearings, respectively. When the first-stage reduction mechanism is a flange input, the two eccentric sections are supported and connected to the first inner cycloidal wheel 9 and the second inner cycloidal wheel 10 via bearings, respectively.

[0047] The phase difference between the two eccentric sections of the secondary pin eccentric crankshaft 12 is 180 degrees; wherein, when the secondary reduction mechanism is a shaft input, the two eccentric sections are supported and connected to the first epicycloid wheel 7 and the second epicycloid wheel 8 respectively through bearings; when the secondary reduction mechanism is a flange input, the two eccentric sections are supported and connected to the first epicycloid wheel 7 and the second epicycloid wheel 8 respectively through bearings.

[0048] In this invention, the intermediate fixed plate 16 is fixed to both ends of the outer shell by at least two support rods, maintaining relative stillness with the outer shell. In each stage of the reduction mechanism, the number of teeth of the cycloidal wheel differs from the number of teeth of the pin wheel by 1, forming a differential planetary transmission mechanism. The reduction ratio of the first-stage reduction mechanism and the reduction ratio of the second-stage reduction mechanism are both 10-30, and the total reduction ratio is 100-900, preferably 100-300. The structure of the second-stage reduction mechanism in the shaft input form is the same as that of the first-stage reduction mechanism in the flange input form, both of which have the cycloidal wheel connected to the eccentric hole of the outer cylinder 6 through a bearing; the structure of the first-stage reduction mechanism in the shaft input form and the second-stage reduction mechanism in the flange input form is the same, both of which have the cycloidal wheel connected to the eccentric section of the central shaft through a bearing, realizing modular interchangeability of the core reduction mechanism.

[0049] In this invention, the bearings between the pin wheel and the output component, the bearing between the pin-eccentric crankshaft and the cycloidal wheel, the bearing between the input shaft 3 and the outer cycloidal wheel, and the bearing between the outer cylinder 6 and the inner cycloidal wheel are all rolling bearings. The output component is the left circumference of the outer cylinder 6 used to fix both ends of the first-stage pin wheel 1, or the left outer circumference of the central shaft. The bearings provided at the double eccentric holes of the outer cylinder 6 are multi-ball rolling bearings, and the load borne by a single ball is less than the single ball load of the bearing at the pin-eccentric crankshaft.

[0050] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0051] Example 1 like Figure 1 As shown, a two-stage reducer based on an incycloid and an excycloid includes a first-stage pinwheel 1, a first-stage support rod 2, a left-side housing 4, an input shaft 3, a first-stage eccentric crankshaft with a pin 5, an outer cylinder 6, a first excycloid wheel 7, a second excycloid wheel 8, a first incycloid wheel 9, a second incycloid wheel 10, a right-side housing 11, a second-stage eccentric crankshaft with a pin 12, a second-stage pinwheel 13, an output shaft 14, a second-stage support rod 15, and an intermediate fixed plate 16.

[0052] One end of the input shaft 3 is fixed to the left outer casing 4 by a bearing, and the other end is fixed to the left inner ring of the output shaft 14 by a bearing. The primary reduction mechanism includes three or more circumferentially distributed primary pin eccentric crankshafts 5, a first epicycloid wheel 7, a second epicycloid wheel 8, and an intermediate fixed plate 16. The first epicycloid wheel 7 and the second epicycloid wheel 8 are supported by bearings on the two eccentric sections of the primary pin eccentric crankshaft 5. The two ends of the primary pin eccentric crankshaft 5 are respectively fixed to the left outer shell 4 and the intermediate fixed plate 16 by bearings. The centers of the first epicycloid wheel 7 and the second epicycloid wheel 8 are respectively connected to the double eccentric sections of the input shaft 3 by bearings. The intermediate fixed plate 16 is fixed to the left outer shell 4 and the right outer shell 11 at both ends by a primary support rod 2 and a secondary support rod 15, respectively. The first-level output is the same as the second-level input mechanism, which includes a first-level pinwheel 1 and an outer cylinder 6. The two ends of the first-level pinwheel 1 are evenly fixed to the left circumference of the outer cylinder 6 by bearings. The outer cylinder 6 is fixed to the inner circumference of the left outer shell 4 by bearings. The secondary reduction mechanism includes three or more circumferentially distributed secondary pin-shaped eccentric crankshafts 12, a first inner cycloidal wheel 9, a second inner cycloidal wheel 10, and an intermediate fixed disk 16. The first inner cycloidal wheel 9 and the second inner cycloidal wheel 10 are connected to two eccentric holes on the right side of the outer cylinder 6 via bearings. The circumferential rotation of the outer cylinder 6 is converted into the eccentric rotation of the inner cycloidal disks through the bearings. Figure 5 The outer cylinder 6 moves in a circular motion around the center O1, and the center O2 of the inner cycloidal disk rotates eccentrically around O1 with an eccentricity e as the radius. The first inner cycloidal wheel 9 and the second inner cycloidal wheel 10 are supported by bearings on the two eccentric sections of the secondary pin eccentric crankshaft 12. The two ends of the secondary pin eccentric crankshaft 12 are fixed to the right outer shell 11 and the middle fixed plate 16 by bearings respectively. The secondary output mechanism includes a secondary pinwheel 13 and an output shaft 14. The two ends of the secondary pinwheel 13 are evenly fixed to the outer circumference of the output shaft 14 by bearings. One end of the output shaft 14 is fixed to the right outer casing 11 by bearings, and the other end is fixed to the inner ring of the middle fixed plate 16 by bearings.

[0053] The shaft extension end of the input shaft 3 is a double eccentric section with a phase difference of 180 degrees. The double eccentric section is supported and connected to the first outer cycloidal wheel 7 and the second outer cycloidal wheel 8 respectively through bearings.

[0054] The phase difference between the two eccentric sections of the first-stage pin eccentric crankshaft 5 is 180 degrees, and the two eccentric sections are supported and connected to the first epicycloid wheel 7 and the second epicycloid wheel 8 respectively through bearings.

[0055] The two eccentric sections of the secondary pin eccentric crankshaft 12 have a phase difference of 180 degrees, and the two eccentric sections are supported and connected to the first inner cycloidal wheel 9 and the second inner cycloidal wheel 10 respectively through bearings.

[0056] The phase difference between the two eccentric holes on the outer cylinder 6 that fix the inner cycloidal disk is 180 degrees. The two eccentric holes are supported and connected to the first inner cycloidal wheel 9 and the second inner cycloidal wheel 10 respectively through bearings.

[0057] The intermediate fixed plate 16 is fixed to the left outer shell 4 and the right outer shell 11 by the primary support rod 2 and the secondary support rod 15 respectively, and remains relatively stationary with respect to the outer shell.

[0058] The left outer casing 4 and the right outer casing 11 are fixed. The input shaft 3 is connected to an external input. The rotation of the input shaft 3 drives the first outer cycloidal wheel 7 and the second outer cycloidal wheel 8 to swing. The first outer cycloidal wheel 7 and the second outer cycloidal wheel 8 squeeze the first-stage needle wheel 1, thereby driving the outer cylinder 6 to rotate. The circumferential rotation of the outer ring of the outer cylinder 6 is converted into the eccentric motion of the inner ring eccentric hole, thereby driving the first inner cycloidal wheel 9 and the second inner cycloidal wheel 10 to swing eccentrically. The first inner cycloidal wheel 9 and the second inner cycloidal wheel 10 squeeze the second-stage needle wheel 13, thereby driving the output shaft 14 to rotate.

[0059] In this example, the number of first-stage pinwheels (1) is 10, and the number of protrusions on the cycloidal wheel is 9, forming a one-dimensional difference mechanism. The first-stage reduction ratio is equal to the number of pinwheels, i.e., the reduction ratio is 10. The input shaft (3) rotates 10 times, and the pinwheels drive the outer cylinder (6) to rotate 1 time. The number of second-stage pinwheels (13) is 10, and the number of protrusions on the inner cycloidal wheel is 11, also forming a one-dimensional difference mechanism. The second-stage reduction ratio is equal to the number of pinwheels, i.e., the reduction ratio is 10. The outer cylinder (6) rotates 10 times, and the output shaft (14) rotates 1 time. The total reduction ratio is 10 * 10 = 100.

[0060] Example 2 like Figure 2 As shown, a two-stage reducer based on an inner cycloid and an outer cycloid includes a first-stage pinwheel 1, a first-stage support rod 2, a right-side housing 11, a rotating shaft 17, a first-stage eccentric crankshaft with a pin 5, an output flange 18, a first outer cycloid wheel 7, a second outer cycloid wheel 8, a first inner cycloid wheel 9, a second inner cycloid wheel 10, an input flange 19, a second-stage eccentric crankshaft with a pin 12, a second-stage pinwheel 13, a left-side housing 4, and a middle fixed plate 16.

[0061] One end of the input flange 19 is fixed to the left side of the left outer casing 4 by a bearing; The primary reduction mechanism includes three or more circumferentially distributed secondary pin-shaped eccentric crankshafts 12, a first inner cycloidal wheel 9, a second outer cycloidal wheel 810, and a central fixed plate 16. The secondary pin-shaped eccentric crankshafts 12 of the inner cycloidal wheels have bearings supporting the first inner cycloidal wheel 9 and the second inner cycloidal wheel 10 on their two eccentric sections. The two ends of the secondary pin-shaped eccentric crankshafts 12 of the inner cycloidal wheels are respectively fixed to the left outer casing 4 and the central fixed plate 16 by bearings. The first inner cycloidal wheel 9 and the second inner cycloidal wheel 10 are respectively connected to the double eccentric holes of the input flange 19 via bearings. The circumferential rotation of the input flange 19 and the outer cylinder 6 is converted into the eccentric rotation of the inner cycloidal discs through the bearings. Figure 5The outer cylinder 6 moves in a circular motion around the center O1, and the inner cycloidal disk center O2 rotates eccentrically around O1 with an eccentricity e as the radius. The middle fixed disk 16 is fixed to the left outer shell 4 and the right outer shell 11 by a first-level support rod 2. The primary output is the same as the secondary input mechanism, which includes a secondary pinwheel 13 and a rotating shaft 17. The two ends of the cycloidal secondary pinwheel 13 are evenly fixed inside the rotating shaft 17 by bearings. The two ends of the rotating shaft 17 are respectively fixed to the left outer shell 4 and the right outer shell 11 by bearings. The secondary reduction mechanism includes a primary pin eccentric crankshaft 5 with three or more circumferentially distributed cycloidal wheels, a first cycloidal wheel 7, a second cycloidal wheel 8, and an intermediate fixed plate 16. The first cycloidal wheel 7 and the second cycloidal wheel 8 are connected to the two eccentric sections on the right side of the rotating shaft 17 by bearings. The first cycloidal wheel 7 and the second cycloidal wheel 8 are supported by bearings on the two eccentric sections of the primary pin eccentric crankshaft 5 of the cycloidal wheels. The two ends of the primary pin eccentric crankshaft 5 of the cycloidal wheels are fixed to the right outer shell 11 and the intermediate fixed plate 16 by bearings, respectively. The secondary output mechanism includes a primary pinwheel 1 and an output flange 18. The two ends of the primary pinwheel 1 of the epicycloid are evenly fixed to the inner circumference of the output flange 18 by bearings. The output flange 18 is fixed to the right outer shell 11 by bearings.

[0062] The port extension end of the input flange 19 is a double eccentric hole with a phase difference of 180 degrees. The double eccentric hole is supported and connected to the first inner cycloidal wheel 9 and the second inner cycloidal wheel 10 respectively through bearings.

[0063] The two eccentric sections of the primary pin eccentric crankshaft 512 have a phase difference of 180 degrees, and the two eccentric sections are supported and connected to the first inner cycloidal wheel 9 and the second inner cycloidal wheel 10 respectively through bearings.

[0064] The two eccentric sections of the secondary pin eccentric crankshaft 12 have a phase difference of 180 degrees, and the two eccentric sections are supported and connected to the first epicycloid wheel 7 and the second epicycloid wheel 8 respectively through bearings.

[0065] The phase difference between the two eccentric sections of the fixed outer cycloidal wheel on the rotating shaft 17 is 180 degrees. The two eccentric sections are supported and connected to the first outer cycloidal wheel 7 and the second outer cycloidal wheel 8 respectively through bearings.

[0066] The intermediate fixed plate 16 is fixed to the left outer shell 4 and the right outer shell 11 by a primary support rod 2, and remains relatively stationary with respect to the outer shell.

[0067] The left outer casing 4 and the right outer casing 11 at both ends are fixed. The input flange 19 is connected to the external input. The circumferential rotation of the input flange 19 drives the first inner cycloidal wheel 9 and the second inner cycloidal wheel 10 to swing. The first inner cycloidal wheel 9 and the second inner cycloidal wheel 10 squeeze the secondary pin wheel 13 of the inner cycloidal line, thereby driving the rotating shaft 17 to rotate. The circumferential rotation of the outer ring of the rotating shaft 17 is converted into the eccentric motion of the eccentric section of the rotating shaft 17, thereby driving the first outer cycloidal wheel 7 and the second outer cycloidal wheel 8 to swing eccentrically. The first outer cycloidal wheel 7 and the second outer cycloidal wheel 8 squeeze the primary pin wheel 1 of the outer cycloidal line, thereby driving the output flange 18 to rotate.

[0068] In this example, the number of first-stage pinwheels (10) is 10, the number of protrusions on the inner cycloidal wheel is 11, and the first-stage reduction ratio equals the number of pinwheels, i.e., the reduction ratio is 10. This is a one-dimensional difference mechanism. The input flange (19) rotates 10 times, and the intermediate shaft rotates 1 time. The number of second-stage pinwheels (13) is 10, the number of protrusions on the outer cycloidal wheel is 9, and this is also a one-dimensional difference mechanism. The second-stage reduction ratio equals the number of pinwheels, i.e., the reduction ratio is 10. The intermediate shaft rotates 10 times, and the output flange (18) rotates 1 time. The total reduction ratio is 10 * 10 = 100.

[0069] In common cycloidal reducers, the cycloidal disc is mounted on a bearing on an eccentric shaft, with the bearing located inside the cycloidal disc. Rotation of the shaft causes the cycloidal disc to rotate eccentrically, thus generating epicycloidal motion. The two-stage reduction mechanism in the first example and the first-stage reduction mechanism in the second example are the same, meaning the fixed bearing of the inner cycloidal disc is located on the outer side of the cycloidal disc's circumference, unlike common cycloidal mechanisms. The principle is explained below. Figure 5 A disk with its center at point O. 1， A small circle with radius R1 is placed on a disk, centered at O2 and with radius R2. As the disk rotates, the small circle rotates accordingly. This can be understood as the disk "embracing" the small circle during rotation, or the small circle rotating eccentrically away from O1. By adjusting the position of O2 and the size of R2, the disk contracts into an outer cylinder 6. The distance between O1 and O2 is the eccentric radius. Making it equal to the eccentricity e of the cycloidal motion, the rotation of the outer cylinder 6 will cause O2 to rotate eccentrically, thus producing an inward cycloidal motion.

[0070] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on these embodiments, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art can still combine, add, delete, or otherwise adjust the features of the various embodiments of the present invention according to the circumstances without conflict or creative effort, thereby obtaining different technical solutions that do not fundamentally depart from the concept of the present invention. These technical solutions also fall within the scope of protection of the present invention.

Claims

1. A two-stage reducer based on an incycloid and an excycloid, characterized in that, It includes a housing, a primary input mechanism, a primary reduction mechanism, a primary output / secondary input mechanism, a secondary reduction mechanism, and a secondary output mechanism; The first-stage reduction mechanism and the second-stage reduction mechanism respectively adopt one of external cycloidal pinwheel drive and internal cycloidal pinwheel drive, and the two have different transmission types; Both the first-stage reduction mechanism and the second-stage reduction mechanism include at least one cycloidal wheel, at least three eccentric crankshafts with pins evenly distributed along the circumferential direction, and an intermediate fixing plate for fixing the eccentric crankshafts with pins. The two ends of the eccentric crankshafts with pins are respectively supported on the outer shell and the intermediate fixing plate by bearings, and the eccentric section of the eccentric crankshafts with pins supports the cycloidal wheel by bearings. The primary output and secondary input mechanism and the secondary output mechanism both include a pin wheel. The two ends of the pin wheel are fixed to the corresponding output components by bearings. The pin wheel meshes with the cycloidal wheel of the corresponding stage to achieve speed reduction transmission. The primary input mechanism is driven by the cycloidal wheel of the primary reduction mechanism, the primary output and secondary input mechanism is driven by the pin wheel of the primary reduction mechanism and the cycloidal wheel of the secondary reduction mechanism respectively, and the secondary output mechanism is driven by the pin wheel of the secondary reduction mechanism. Both the primary input mechanism and the secondary output mechanism adopt a two-end support structure with no cantilever output.

2. The two-stage reducer based on an epicycloid and an epicycloid as described in claim 1, characterized in that, The primary input mechanism is an axis input mechanism, and the secondary output mechanism is an axis output mechanism; The shaft input mechanism includes an input shaft, one end of which is supported on the left outer casing by a bearing, and the other end of which is supported on the left inner ring of the output shaft of the shaft output mechanism by a bearing. The first-stage reduction mechanism adopts an external cycloidal pinwheel drive, including two external cycloidal wheels, the centers of which are respectively connected to the double eccentric section of the input shaft through bearings; The primary output and secondary input mechanism includes a primary pin wheel and an outer cylinder. The two ends of the primary pin wheel are evenly fixed to the left circumference of the outer cylinder by bearings. The outer cylinder is supported on the inner circumference of the left outer shell by bearings. The secondary reduction mechanism adopts an internal cycloidal pinwheel drive, including two internal cycloidal wheels, which are respectively connected to the double eccentric holes on the right side of the outer cylinder through bearings; The shaft output mechanism includes a secondary pinwheel and an output shaft. The two ends of the secondary pinwheel are evenly fixed to the outer circumference of the output shaft by bearings. One end of the output shaft is supported by a bearing on the right outer shell, and the other end is supported by a bearing on the inner ring of the intermediate fixed plate.

3. A two-stage reducer based on an epicycloid and an epicycloid as described in claim 2, characterized in that, The first-stage reduction mechanism using epicycloidal pinwheel drive also includes three or more circumferentially distributed first-stage pin eccentric crankshafts. The epicycloidal wheels are supported by bearings on the two eccentric sections of the first-stage pin eccentric crankshafts. The two ends of the first-stage pin eccentric crankshafts are respectively fixed to the outer shell and the intermediate fixed plate by bearings. The intermediate fixed plate is fixed to the outer shell at both ends by a first-stage support rod and a second-stage support rod.

4. A two-stage reducer based on an epicycloid and an epicycloid as described in claim 2, characterized in that, The secondary reduction mechanism using internal cycloidal pinwheel drive also includes three or more circumferentially distributed secondary pin eccentric crankshafts. The internal cycloidal wheel is supported by bearings on the two eccentric sections of the secondary pin eccentric crankshafts, and the two ends of the secondary pin eccentric crankshafts are respectively fixed to the outer shell and the intermediate fixed plate by bearings.

5. A two-stage reducer based on an epicycloid and an epicycloid as described in claim 1, characterized in that, The primary input mechanism is a flange input mechanism, and the secondary output mechanism is a flange output mechanism; The flange input mechanism includes an input flange, which is supported on the left side housing by a bearing. The first-stage reduction mechanism adopts an internal cycloidal pinwheel drive, including two internal cycloidal wheels, which are respectively connected to the double eccentric holes of the input flange through bearings; The primary output and secondary input mechanism includes a primary pinwheel and a central shaft. The two ends of the primary pinwheel are evenly fixed to the outer circumference of the left side of the central shaft by bearings. The two ends of the central shaft are respectively supported by bearings on the left and right outer shells. The secondary reduction mechanism adopts an external cycloidal pinwheel drive, including two external cycloidal wheels, the centers of which are respectively connected to the double eccentric section of the central shaft through bearings; The flange output mechanism includes a secondary pinwheel and an output flange. The two ends of the secondary pinwheel are evenly fixed to the inner circumference of the output flange by bearings, and the output flange is supported by the right outer shell by bearings.

6. A two-stage reducer based on an epicycloid and an epicycloid as described in claim 5, characterized in that, The primary reduction mechanism using an internal cycloidal pinwheel drive also includes three or more circumferentially distributed primary pin eccentric crankshafts. The internal cycloidal wheel is supported by bearings on the two eccentric sections of the primary pin eccentric crankshafts, and the two ends of the primary pin eccentric crankshafts are respectively fixed to the left outer shell and the middle fixed plate by bearings.

7. A two-stage reducer based on an epicycloid and an epicycloid as described in claim 5, characterized in that, The two-stage reduction mechanism using epicycloidal pinwheel drive also includes three or more circumferentially distributed two-stage pin eccentric crankshafts. The epicycloidal wheels are supported by bearings on the two eccentric sections of the two-stage pin eccentric crankshafts. The two ends of the two-stage pin eccentric crankshafts are respectively fixed to the outer shell and the intermediate fixed plate by bearings. The intermediate fixed plate is fixed to the outer shell at both ends by support rods.

8. A two-stage reducer based on an epicycloid and an epicycloid as described in claim 2 or 5, characterized in that, The phase difference between the two eccentric portions of the double eccentric section of the input shaft, the double eccentric hole of the input flange, the double eccentric hole of the outer cylinder, and the two eccentric portions of the double eccentric section of the central shaft is 180 degrees.

9. A two-stage reducer based on an epicycloid and an epicycloid as described in claim 1, characterized in that, The eccentric crankshaft with pin has two eccentric sections with a phase difference of 180 degrees. The two eccentric sections support two cycloidal wheels respectively through bearings.

10. A two-stage reducer based on an epicycloid and an epicycloid as described in claim 1, characterized in that, The intermediate fixing plate is fixed to both ends of the outer shell by at least two support rods, and remains relatively stationary with respect to the outer shell.

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