Speed reducer and robot having same

Abstract

A speed reducer, comprising: an outer housing (1); an output flange (5); a gear ring (2) having first external teeth (21) and second internal teeth (22); a first harmonic rigid gear (3a); a second harmonic rigid gear (3b); an eccentric shaft (4); a central gear (6), the central gear (6) being tightly sleeved on an input shaft section (45); and a motor mounting housing (61), wherein the motor mounting housing (61) is fixedly connected to the outer housing (1), a motor (62) is arranged on the motor mounting housing (61), an output shaft (63) of the motor (62) is coaxially provided with a driving gear (64), the driving gear (64) meshes with the central gear (6), the axis line of the output shaft (63) of the motor (62) is parallel to and does not coincide with the axis line of the input shaft section (45), and the motor (62) is entirety located outside the eccentric shaft. The speed reducer is a hollow speed reducer and has two speed reduction stages, and the mounting position of the motor (62) changes from coaxial mounting to parallelly axial mounting; the hollow cavity of the eccentric shaft (4) facilitates passage of a wire harness, and non-standard needle bearings are mounted at the wire incoming end and the wire outgoing end of the cavity of the eccentric shaft (4), thereby achieving zero wear of the wire harness; the eccentric shaft (4) is matched with the input central gear (6) by means of a special-shaped hole, thereby ensuring that there is no side clearance in both forward and reverse rotation input. Also provided is a robot using the speed reducer.

Description

A reducer and a robot having the same Technical Field

[0001] The invention relates to a reducer and a robot having the same. Background Art

[0002] A reducer is a power transmission mechanism that uses a gear train to reduce output speed and increase output torque. Currently, there are two main types of precision reducers for robot joints on the market: RV reducers and harmonic reducers. The second-stage cycloid pinwheel small-tooth-difference transmission in the RV reducer is a KHV-type gear transmission mechanism consisting of a single-tooth-difference internal gear pair consisting of a short-spoke epicycloid gear and a pin gear, an eccentric element (planet carrier), and an output mechanism. A harmonic gear transmission mechanism is a modified small-tooth-difference planetary gear transmission consisting of a wave generator, a flexible gear, and a rigid gear. The flexible gear has a small tooth difference with the rigid gear, and its elastic deformation acts as a modified planetary gear within the mechanism. However, RV reducers suffer from wear during transmission, which can lead to transmission errors, hindering output precision control, and increasing machining difficulty. The transmission error and accuracy of harmonic gear transmissions need to be further improved. Furthermore, both transmission mechanisms suffer from complex speed ratio adjustment or a narrow adjustable speed ratio range, resulting in significant limitations when integrated into robots and limited design freedom.

[0003] Although some existing reducers have a large degree of freedom, they are difficult to pass through and are prone to causing significant wear and tear on the line. For example, the robot precision joint reducer with publication number CN106763526B has a first eccentric gear and a second eccentric gear fixed on the eccentric shaft, and a thin-walled elastic gear ring with internal and external teeth. The internal teeth of the thin-walled elastic gear ring mesh with the first and second eccentric gears, and the external teeth of the thin-walled elastic gear ring mesh with the teeth on the inner wall of the output flange. The left and right box covers are buckled and fixed together. The first eccentric gear, the second eccentric gear and the thin-walled elastic gear ring are placed between the left and right box covers. A first retainer and a ball are clamped between the left box cover and the output flange, and a first retainer and a ball are clamped between the right box cover and the output flange. A second retainer and a cylindrical roller are clamped between the left box cover and the eccentric shaft. This technical solution is a solid reducer. The hollow eccentric shaft is the motor shaft extension hole, which makes passing through the line difficult and is prone to causing significant wear and tear on the line.

[0004] In order to solve the above problems, the present invention provides a reducer and a robot having the same, so as to solve the problems of the previous reducer being difficult to pass through the line and easy to wear.

[0005] Summary of the Invention

[0006] In view of the above problems, the purpose of the present invention is to provide a reducer and a robot having the same, so as to reduce the wear of the wire, and the reducer has multiple speed ratios, high torsional stiffness and high precision, and at the same time has a compact structure and greater design freedom.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] A reducer, comprising an outer shell and an output flange, wherein the outer shell is provided with a first internal tooth; the reducer further comprises:

[0009] a gear ring capable of elastic deformation, the gear ring having first external teeth and second internal teeth, the gear ring being disposed within the outer shell and the first external teeth meshing with the first internal teeth;

[0010] First harmonic steel gear;

[0011] A second harmonic steel gear is eccentrically arranged relative to the first harmonic steel gear;

[0012] An eccentric shaft, which is used to drive the first harmonic steel gear and the second harmonic steel gear to rotate, and the eccentric shaft is provided with a hollow cavity, which axially penetrates the eccentric shaft and has two open ends;

[0013] A central gear, which is used to drive the eccentric shaft to rotate; the central gear is tightly sleeved on the input shaft segment;

[0014] a motor mounting shell, the motor mounting shell being fixedly connected to the outer shell, the motor being provided on the motor mounting shell, the output shaft of the motor being coaxially provided with a driving gear, the driving gear being meshed with the central gear, the axis of the output shaft of the motor being parallel to the axis of the input shaft segment and not overlapping; the motor being entirely located outside the eccentric shaft;

[0015] Wherein, the first harmonic steel gear and the second harmonic steel gear both have second external teeth capable of meshing with the second internal teeth, the first harmonic steel gear and the ring gear have a first meshing point, the second harmonic steel gear and the ring gear have a second meshing point, and the first meshing point and the second meshing point are separated by a distance in the circumferential direction of the ring gear;

[0016] The eccentric shaft comprises a first shaft segment, a second shaft segment and an input shaft segment, wherein the first shaft segment, the second shaft segment and the input shaft segment are eccentrically arranged, the first harmonic steel gear is arranged on the first shaft segment, the second harmonic steel gear is arranged on the second shaft segment, and the central gear is arranged on the input shaft segment;

[0017] The output flange is rotatably disposed in the outer shell, and the output flange is connected to the first harmonic steel gear and the second harmonic steel gear.

[0018] Preferably, the reducer further includes at least two needle roller bearings, and the two needle roller bearings are arranged on the inner wall of the hollow cavity at intervals.

[0019] Preferably, a bearing is provided between the first harmonic steel gear and the first shaft segment, and a bearing is provided between the second harmonic steel gear and the second shaft segment.

[0020] Preferably, the first meshing portion and the second meshing portion are respectively located on two opposite sides of the gear ring.

[0021] Preferably, the eccentric shaft further has a third shaft segment, the output flange is sleeved on the third shaft segment with a bearing provided therebetween; and a bearing is provided between the output flange and the outer shell.

[0022] Preferably, the reducer further includes a motor end flange, the motor end flange and the output flange are arranged opposite to each other and connected to each other, and the first harmonic steel gear and the second harmonic steel gear are arranged between the motor end flange and the output flange.

[0023] Preferably, the motor end flange is rotatably disposed in the outer shell with a bearing disposed therebetween, and the eccentric shaft further has a fourth shaft segment, the motor end flange is sleeved on the fourth shaft segment with a bearing disposed therebetween.

[0024] Preferably, the first harmonic steel gear and the second harmonic steel gear respectively have a through hole, the output flange and the motor end flange are connected by bolts, and the bolts pass through the through holes of the first harmonic steel gear and the second harmonic steel gear, and the aperture of the through hole is larger than the outer diameter of the bolt.

[0025] A robot comprises a joint, wherein the joint adopts the reducer as described above.

[0026] Preferably, the robot is a humanoid robot, the joints include knee joints or hip joints, and the knee joints or hip joints use the reducer as described above.

[0027] The present invention adopts the above solution and has the following advantages compared with the prior art:

[0028] 1. The present invention is a hollow reducer with two reduction stages. The motor installation position is changed from coaxial installation to parallel shaft installation. The hollow cavity of the eccentric shaft is convenient for the passage of the wiring harness. Non-standard needle bearings are installed at both ends of the inlet and outlet of the eccentric shaft cavity to achieve zero wear of the wiring harness. The eccentric shaft and the input center gear are matched with special-shaped holes to ensure that there is no side clearance in both forward and reverse inputs.

[0029] 2. The reducer of the present invention is lightweight, compact, and easy to assemble. In particular, the steps for assembling it into an industrial robot are relatively simple and convenient, and wiring is easy, effectively reducing the risk of cable scratches or wear. At the same time, during the gear meshing process, the meshing of the outer teeth of the ring gear with the inner teeth of the outer shell controls the flexible deformation of the ring gear. In this controlled deformation state, the inner teeth of the elastic ring gear and the eccentric gear have a large meshing angle, achieving high torsional stiffness. By adjusting the number of teeth on the center gear, multiple speed ratios can be achieved within the same outer envelope size. The reducer has the characteristics of high precision and high torsional stiffness and can be applied to various speed ratio working conditions, with a large degree of design freedom.

[0030] 3. The robot of the present invention has a lightweight and compact reducer, has the characteristics of high precision and high torsional rigidity, and can be applied to working conditions of various speed ratios, and is suitable as a humanoid robot. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solution of the present invention, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] [Corrected 08.11.2023 according to Rule 91] Figure 1 is a front view of a reducer according to an embodiment of the present invention.

[0033] FIG2 is a left side view of the reducer shown in FIG1 .

[0034] FIG3 is a right side view of the reducer shown in FIG1 .

[0035] FIG4 is a rotational cross-sectional view taken along the AA direction in FIG3 .

[0036] FIG5 is a cross-sectional view of a reducer including a motor and a motor mounting housing according to an embodiment of the present invention.

[0037] FIG6 is a partial enlarged view of point B in FIG5.

[0038] FIG7 is a partial enlarged view of point C in FIG5 .

[0039] FIG8 is a structural diagram of an output flange according to an embodiment of the present invention.

[0040] FIG9 is a left side view of the output flange shown in FIG8 .

[0041] FIG10 is a rotational cross-sectional view taken along the DD direction in FIG9 .

[0042] FIG11 is a structural diagram of a motor end flange according to an embodiment of the present invention.

[0043] FIG12 is a left side view of the motor end flange shown in FIG11 .

[0044] FIG13 is a rotational cross-sectional view taken along the EE direction in FIG12 .

[0045] FIG14 is a left side view of a first harmonic steel gear according to an embodiment of the present invention.

[0046] FIG15 is a rotational cross-sectional view taken along the FF direction in FIG14 .

[0047] Figure 16 is a schematic diagram of the special-shaped connection between the eccentric shaft and the central gear.

[0048] Reference numerals: 1. Outer housing; 11. First internal tooth; 2. Ring gear; 21. First external tooth; 22. Second internal tooth; 3a. First harmonic gear; 3b. Second harmonic gear; 31. Second external tooth; 32. Through hole; 33. Screw hole; 4. Eccentric shaft; 40. Hollow cavity; 41. First shaft section; 42. Second shaft section; 43. Third shaft section; 44. Fourth shaft section; 45. Input shaft section; 46. Needle roller bearing; 5. Output flange; 50. Output end connection port; 51. End cover; 52. Bolt hole; 53. Stud; 6. Center gear; 61. Motor mounting housing; 62. Motor; 63. Output shaft; 64. Driving gear; 7. Motor end flange; 71. Bolt hole; 72. Screw hole; 8. Bearing; 9. Sealing ring; 101. Bolt; 102. Screw 103. First protrusion; 104. First groove; 105. Second protrusion; 106. Second groove. DETAILED DESCRIPTION

[0049] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art. It should be noted that the description of these embodiments is intended to help understand the present invention, but does not constitute a limitation of the present invention.

[0050] This embodiment provides a reducer for a robot joint, specifically for use as a knee or hip joint. Referring to Figures 1 to 15 , the reducer comprises an outer housing 1, a ring gear 2, a first harmonic steel gear 3a, a second harmonic steel gear 3b, an eccentric shaft 4, an output flange 5, and a center gear 6. The outer housing 1 is hollow and has a ring of first internal teeth 11. The ring gear 2 is made of high-toughness alloy steel, capable of undergoing minimal elastic deformation. The ring gear 2 has first external teeth 21 and second internal teeth 22, which are disposed within the outer housing 1, with the first external teeth 21 meshing with the first internal teeth 11. The first harmonic steel gear 3a and the second harmonic steel gear 3b are arranged side by side, with the second harmonic steel gear 3b eccentrically disposed relative to the first harmonic steel gear 3a. The eccentric shaft 4 is used to drive the first and second harmonic steel gears 3a and 3b in rotation. The center gear 6 is used to input power to drive the eccentric shaft 4 in rotation.

[0051] As shown in Figures 1 to 5 , the outer housing 1 and the ring gear 2 are both hollow, open-ended cylindrical bodies, coaxially arranged. The outer housing 1 is sleeved onto the ring gear 2, and the two mesh with each other via first internal teeth 11 and first external teeth 21. The outer housing 1 can be fixedly connected to other robot components, for example, via fasteners, to securely connect the reducer to other robot components. The ring gear 2 is a thin-walled, elastic ring gear with a radial width less than 10% of its outer diameter, capable of undergoing minimal elastic deformation.

[0052] As shown in Figures 2 and 8 to 10 , the output flange 5 is rotatably disposed within the outer housing 1 and is connected to the first harmonic gear 3a and the second harmonic gear 3b. Specifically, the output flange 5 is rotatably disposed on the eccentric shaft 4. Furthermore, the output flange 5 is located within the outer housing 1. As the first harmonic gear 3a and the second harmonic gear 3b rotate, the output flange 5 also rotates relative to the outer housing 1.

[0053] Furthermore, as shown in Figures 11 to 13 , the reducer also includes a motor end flange 7. The motor end flange 7 and the output flange 5 are arranged opposite each other and connected to each other, and the first harmonic steel gear 3a and the second harmonic steel gear 3b are arranged between the motor end flange 7 and the output flange 5. The motor end flange 7 is rotatably mounted on the eccentric shaft 4 and is located within the outer shell 1.

[0054] With reference to Figures 4 to 7 , the first harmonic steel gear 3a and the second harmonic steel gear 3b are two gears of identical structure and specifications, eccentrically mounted on the eccentric shaft 4. Both the first harmonic steel gear 3a and the second harmonic steel gear 3b have second external teeth 31 that mesh with the second internal teeth 22 of the ring gear 2. Figures 14 and 15 schematically illustrate the structure of the first harmonic steel gear 3a. The structure of the second harmonic steel gear 3b is identical to that of the first harmonic steel gear 3a. Specifically, in this embodiment, the first harmonic steel gear 3a and the second harmonic steel gear 3b are arranged side by side within the ring gear 2, with the first harmonic steel gear 3a on the right and the second harmonic steel gear 3b on the left. The first harmonic gear 3a has a first meshing portion with the ring gear 2, and the second harmonic gear 3b has a second meshing portion with the ring gear 2. The first meshing portion and the second meshing portion are spaced a distance apart in the circumferential direction of the ring gear 2. Furthermore, the first meshing portion and the second meshing portion are respectively located on opposite sides of the ring gear 2. For example, the first meshing portion is located on the upper side of the ring gear 2, and the second meshing portion is located on the lower side of the ring gear 2.

[0055] As shown in Figures 4 and 5, the eccentric shaft 4 is provided with a hollow cavity 40, which passes through the eccentric shaft 4 axially and has open ends. The hollow cavity 40 is used for wiring (such as the power transmission cable or signal transmission cable of the motor described below) or to provide installation space for other components (such as the motor 62 described below), which helps to make the entire reducer structure compact; at the same time, it helps to make the entire reducer lightweight; thus, it is more suitable for small industrial robots, such as six-axis robots or small robotic arms. As shown in Figures 4 and 7, the eccentric shaft 4 has a first shaft section 41, a second shaft section 42, a third shaft section 43, a fourth shaft section 44 and an input shaft section 45. Specifically in this embodiment, the input shaft section 45, the fourth shaft section 44, the first shaft section 41, the second shaft section 42 and the fourth shaft section 44 are arranged in sequence from right to left. The third shaft segment 43, the fourth shaft segment 44, and the input shaft segment 45 are coaxial, meaning they share a common axis, designated as the first axis. The first shaft segment 41 and the second shaft segment 42 are each eccentrically disposed relative to the first axis, and the first shaft segment 41 and the second shaft segment 42 are eccentrically disposed relative to each other. Specifically, in this embodiment, the axis of the first shaft segment 41 is designated as the second axis, and the axis of the second shaft segment 42 is designated as the third axis. The first, second, and third axes are parallel to each other, and the second and third axes are located on opposite sides of the first axis. Furthermore, the first, second, and third axes are located in the same plane, and the second and third axes are located on opposite sides of the first axis. The second axis is spaced d1 from the first axis, and the third axis is spaced d2 from the first axis. Advantageously, the spacing d1 is equal to the spacing d2.

[0056] As shown in Figures 6 and 7 , the first harmonic gear 3a is mounted on the first shaft segment 41, the second harmonic gear 3b is mounted on the second shaft segment 42, the output flange 5 is mounted on the third shaft segment 43, the motor end flange 7 is mounted on the fourth shaft segment 44, and the center gear 6 is mounted on the input shaft segment 45. Specifically, a bearing 8 is provided between the first harmonic gear 3a and the first shaft segment 41 of the eccentric shaft 4, between the second harmonic gear 3b and the second shaft segment 42, between the output flange 5 and the third shaft segment 43, and between the motor end flange 7 and the fourth shaft segment 44. The center gear 6 is tightly fitted onto the input shaft segment 45. The specific assembly process is as follows: the center gear 6 is heated to expand due to the heat, then fitted onto the input shaft segment 45. After cooling, the center gear 6 is tightly fitted onto the input shaft segment 45 of the eccentric shaft 4. The heating temperature is 80°C for 3 to 5 minutes. The center hole diameter of the center gear 6 is 30 to 100 mm.

[0057] As shown in Figures 4 and 5, in this embodiment, the output flange 5 and the motor end flange 7 are both substantially located within the outer housing 1, making the reducer structure more compact. Specifically, the output flange 5 is connected to the inner wall of the left side of the outer housing 1 via a bearing 8, and the motor end flange 7 is connected to the inner wall of the right side of the outer housing 1 via a bearing 8. A sealing ring 9 is also provided between the output flange 5 and the outer housing 1. The reducer also includes an end cap 51, which is positioned in the gap between the output flange 5 and the left end of the eccentric shaft 4.

[0058] The first harmonic gear 3a and the second harmonic gear 3b are connected to the output flange 5 via multiple bolts 101, thereby outputting torque. As shown in Figures 8 to 10, the output flange 5 is provided with multiple bolt holes 52; as shown in Figures 11 to 13, the motor end flange 7 is provided with multiple bolt holes 71; and as shown in Figures 14 and 15, the first harmonic gear 3a and the second harmonic gear 3b each have through-holes 32. Bolts 101 pass through the bolt holes 52 of the output flange 5, the through-holes 32 of the second harmonic gear 3b and the first harmonic gear 3a, and the bolt holes 71 of the motor end flange 7, connecting them. Furthermore, the diameter of the through-holes 32 is larger than the outer diameter of the bolts 101, allowing the first and second harmonic gears 3a, 3b to rotate driven by the eccentric shaft 4. The diameters of the bolt holes 52 of the output flange 5 and the bolt holes 71 of the motor end flange 7 match the outer diameter of the bolts 101, ensuring a tight fit.

[0059] The output flange 5 and the motor end flange 7 are fixedly connected, while the first harmonic steel gear 3a and the second harmonic steel gear 3b are limited to prevent them from moving along the axial direction of the eccentric shaft 4. Specifically, the output flange 5 and the motor end flange 7 are connected by screws 102. Referring to Figures 8 to 10, the output flange 5 has a plurality of studs 53 extending to the right; referring to Figures 11 to 13, a plurality of screw holes 72 are provided on the motor end flange 7; and referring to Figures 14 and 15, screw holes 33 are provided on the first harmonic steel gear 3a and the second harmonic steel gear 3b, respectively. The screws 102 pass through the screw holes 72 of the motor end flange 7, the screw holes 32 of the first harmonic steel gear 3a and the second harmonic steel gear 3b, and are then inserted into the studs 53 of the output flange 5 to connect the four. The diameters of the screw holes 32 of the first harmonic gear 3 a and the second harmonic gear 3 b are larger than the screws 102 , so as to allow the first harmonic gear 3 a and the second harmonic gear 3 b to rotate driven by the eccentric shaft 4 .

[0060] Specifically in this embodiment, the second axis (also the rotation axis of the first harmonic gear 3a) and the third axis (also the rotation axis of the first harmonic gear 3a) are located above and below the first axis, respectively. The distance d1 between the second axis and the first axis is equal to the distance d2 between the third axis and the first axis. Accordingly, the first harmonic gear 3a meshes with the upper side of the ring gear 2 from above, and the second harmonic gear 3b meshes with the lower side of the ring gear 2 from below. In other words, the first and second meshing points are located above and below the ring gear 2, respectively. The ring gear 2 initially has an overall annular shape. During operation, the upper and lower portions of the ring gear 2 are squeezed outward, slightly deforming in the vertical direction, while the left and right sides deform inward. This results in a large number of meshing tooth pairs and a larger meshing angle.

[0061] As shown in Figure 5, the reducer also includes a motor mounting shell 61, which is fixedly connected to the outer shell 1. A motor 62 is provided on the motor mounting shell 61, and a driving gear 64 is coaxially provided on the output shaft 63 of the motor 62. The driving gear 64 is meshed with the center gear 6, and the axis of the output shaft 63 of the motor 62 is parallel to the axis of the input shaft section 45 and does not overlap. As shown in Figure 5, the motor 62 is located on the upper side of the eccentric shaft 4 as a whole. The eccentric shaft 4 is plugged into the motor mounting shell 61 and a bearing 8 and a sealing ring 9 are provided between the two; further, the center gear 6 and the driving gear 64 are meshed with long straight teeth to ensure that their meshing length meets the requirements and increase the stability of their contact, thereby reducing noise transmission and improving related NHV performance.

[0062] The reducer also includes at least two needle roller bearings 46, which are arranged on the inner wall of the hollow cavity 40 at intervals. When other components or cables are arranged in the hollow cavity 40 of the eccentric shaft 4, these components or cables can be fixed to the needle roller bearings 46 to avoid interference with the rotation of the eccentric shaft 4.

[0063] In the reducer of this embodiment, the torque output by the motor 62 is transmitted to the eccentric shaft 4 through the central gear 6, and the eccentric shaft 4 rotates. At the same time, the first harmonic steel gear 3a and the second harmonic steel gear 3b respectively have multiple teeth that mesh with the ring gear 2. Due to the small tooth difference transmission, the first harmonic steel gear 3a and the second harmonic steel gear 3b rotate at a reduced speed under the drive of the eccentric shaft 4 and the action of the ring gear 2, and the torque is transmitted to the output flange 5 through the bolt 101, driving the output flange 5 to rotate at a reduced speed.

[0064] Referring to Figures 2, 4, and 9-10, the left end surface of the output flange 5 is provided with an output connection port 50, specifically a blind hole extending left and right. When assembled into the industrial robot, the reducer outputs torque to the driven object on the left. During assembly, after the outer shell 1 and the driven object's supporting components (e.g., the housing) are assembled using fasteners, the right end of the driven object is automatically pressed into the output connection port 50 of the output flange 5, thereby reducing the power input from the motor 62 and transmitting it to the driven object.

[0065] The reducer of this embodiment is lightweight, compact, and easy to assemble. The outer shell 1 can be fixed, while the transmission components are rotatably arranged in the outer shell 1. In particular, the steps for assembling it into an industrial robot are relatively convenient and concise, and wiring is convenient, effectively reducing the risk of cables being scratched or worn. At the same time, during the gear meshing process, the meshing of the outer teeth of the ring gear 2 with the inner teeth of the outer shell 1 will make the flexible deformation of the ring gear 2 controlled. Moreover, in this controlled deformation state, the inclusion angle between the inner teeth of the elastic ring gear 2 and the eccentric gear can reach 80°, achieving the purpose of high torsional stiffness. By adjusting the number of teeth of the center gear 6, multiple speed ratios can be achieved under the same outer envelope size. This reducer has the characteristics of high precision and high torsional stiffness and can be applied to working conditions with multiple speed ratios, with a large degree of design freedom.

[0066] As shown in Reference Figure 16, the connection between the center gear 6 and the eccentric shaft 4 is a special-shaped connection. A number of first protrusions 103 and first grooves 104 are arranged in sequence on the outer surface of the eccentric shaft 4 that contacts the center gear 6. The outer surface of the center gear 6 is provided with second protrusions 105 and second grooves 106 that are compatible with the first protrusions 103 and the first grooves 104 on the outer surface of the eccentric shaft 4, thereby achieving the purpose of enhancing the fit between the eccentric shaft 4 and the center gear 6. Moreover, due to the wavy setting, it can be ensured that there is no gap during forward and reverse rotation.

[0067] In this embodiment, an industrial robot adopts the above-mentioned speed reducer in its joints. Specifically, the industrial robot is a humanoid robot, and the knee joint or hip joint of the humanoid robot adopts the above-mentioned speed reducer.

[0068] As used in this specification and claims, the terms "comprises" and "include" merely indicate the inclusion of the steps and elements specifically identified, and these steps and elements do not constitute an exclusive list; a method or apparatus may also include other steps or elements. The term "and / or" as used herein includes any combination of one or more of the associated listed items.

[0069] It should be noted that, unless otherwise specified, when a feature is referred to as being "fixed" or "connected" to another feature, it may be directly fixed or connected to the other feature or indirectly fixed or connected to the other feature. Furthermore, the terms "upper," "lower," "left," and "right" used in this disclosure are intended solely to describe the relative positions of the components of the disclosure as shown in the accompanying drawings. For reference, see FIG5 .

[0070] It should be further understood that in this disclosure, "plurality" refers to two or more, and other quantifiers are similar. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, and B exists alone.

[0071] It will be further understood that the terms "first," "second," and the like are used to describe various types of information, but such information should not be limited to these terms. These terms are used solely to distinguish information of the same type from one another and do not indicate a particular order or level of importance. In fact, the terms "first," "second," and the like are fully interchangeable. For example, first information could be referred to as second information, and similarly, second information could be referred to as first information without departing from the scope of this disclosure.

[0072] The above embodiment is intended only to illustrate the technical concepts and features of the present invention and is a preferred embodiment. Its purpose is to enable those skilled in the art to understand the contents of the present invention and implement them accordingly. It is not intended to limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the principles of the present invention are intended to be covered by the scope of protection of the present invention.

Claims

1. A reducer, comprising an outer shell and an output flange, characterized in that: The outer shell is provided with a first internal tooth; the reducer further comprises: A gear ring capable of elastic deformation, the gear ring having a first external tooth and a second internal tooth, the gear ring being disposed in the outer shell and the first external tooth meshing with the first internal tooth; First harmonic steel gear; A second harmonic steel gear, which is eccentrically arranged relative to the first harmonic steel gear; An eccentric shaft, which is used to drive the first harmonic steel gear and the second harmonic steel gear to rotate, and the eccentric shaft is provided with a hollow cavity, and the hollow cavity axially penetrates the eccentric shaft and has two open ends; A central gear, which is used to drive the eccentric shaft to rotate; the central gear is tightly sleeved on the input shaft section; A motor mounting shell, wherein the motor mounting shell is fixedly connected to the outer shell, a motor is arranged on the motor mounting shell, a driving gear is coaxially arranged on the output shaft of the motor, the driving gear is meshed with the central gear, and the axis center line of the output shaft of the motor is parallel to the axis center line of the input shaft section and does not overlap; the motor as a whole is located outside the eccentric shaft; Wherein, the first harmonic steel gear and the second harmonic steel gear both have second external teeth that can mesh with the second internal teeth, the first harmonic steel gear and the gear ring have a first meshing point, the second harmonic steel gear and the gear ring have a second meshing point, and the first meshing point and the second meshing point are separated by a distance in the circumferential direction of the gear ring; The eccentric shaft comprises a first shaft segment, a second shaft segment and an input shaft segment, the first shaft segment, the second shaft segment and the input shaft segment are eccentrically arranged, the first harmonic steel gear is arranged on the first shaft segment, the second harmonic steel gear is arranged on the second shaft segment, and the central gear is arranged on the input shaft segment; The output flange is rotatably disposed in the outer shell, and the output flange is connected to the first harmonic steel gear and the second harmonic steel gear.

2. The reducer according to claim 1, characterized in that: The reducer further comprises at least two needle roller bearings, and the two needle roller bearings are arranged on the inner wall of the hollow cavity at intervals.

3. The reducer according to claim 1, characterized in that: A bearing is provided between the first harmonic steel gear and the first shaft segment, and a bearing is provided between the second harmonic steel gear and the second shaft segment.

4. The reducer according to claim 1, characterized in that: The first meshing portion and the second meshing portion are respectively located at two opposite sides of the gear ring.

5. The reducer according to claim 1, characterized in that: The eccentric shaft also has a third shaft section, the output flange is sleeved on the third shaft section with a bearing arranged between the two; a bearing is arranged between the output flange and the outer shell.

6. The reducer according to claim 1, characterized in that: The reducer also includes a motor end flange, the motor end flange and the output flange are arranged opposite to each other and connected to each other, and the first harmonic steel gear and the second harmonic steel gear are arranged between the motor end flange and the output flange.

7. The reducer according to claim 1, characterized in that: The motor end flange is rotatably arranged in the outer shell and a bearing is arranged between the two. The eccentric shaft also has a fourth shaft section. The motor end flange is sleeved on the fourth shaft section and a bearing is arranged between the two.

8. The reducer according to claim 6 or 7, characterized in that: The first harmonic steel gear and the second harmonic steel gear respectively have through holes, the output flange and the motor end flange are connected by bolts, and the bolts pass through the through holes of the first harmonic steel gear and the second harmonic steel gear, and the aperture of the through hole is larger than the outer diameter of the bolt.

9. A robot comprising a joint, characterized in that: The joint adopts the reducer as described in any one of claims 1 to 8.

10. The robot according to claim 9, characterized in that: The robot is a humanoid robot, the joints include knee joints or hip joints, and the knee joints or hip joints use the reducer as described in any one of claims 1 to 8.

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