Thin-type cycloidal speed reducer

Abstract

The application discloses a thin cycloidal speed reducer, comprising an input eccentric generator, a disc type cycloidal speed reduction structure, a mounting structure and a rear drive motor. The input eccentric generator comprises a mounting flange plate, an eccentric generation bearing mounting pin, an eccentric generation bearing and a first gasket; the disc type cycloidal speed reduction structure comprises a cycloidal disc, a peripheral roller, a roller mounting pin, an upper and lower side mounting pin fixed flange ring, an output load bearing, an output load bearing retainer ring and a copper column; and the mounting structure comprises an output flange ring, a mounting flange ring and an output bearing. The eccentric inertia of the parts is extremely small, thereby adapting to high-speed working conditions; the cycloidal structure has high load bearing capacity and matches high-speed input, thereby realizing high power density; the cycloidal speed reducer has obvious power density advantages while ensuring high precision, and to a certain extent, eliminates the high-speed vibration problem of traditional cycloidal speed reducers.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of robot technology, in particular to a thin cycloidal pin wheel reducer suitable for robot joints. BACKGROUND

[0002] For robot joints, it is often required to have a large torque, but the speed requirement is not high. This leads to the inevitable choice of using a reducer to increase the joint torque. At present, the reducers mainly used in the robot industry are harmonic reducers and RV reducers, but the flexspline of the harmonic reducer has the problems of poor rigidity and weak overload capacity, and the RV reducer adopts gear reduction and cycloidal pin wheel reduction in cascade, and the mass is often large, which is not suitable for mobile robots. In the prior art scheme in the field of mobile robots, there is a lack of a high-load-capacity high-energy-density reduction scheme.

[0003] At present, the Chinese invention patent with publication number CN113915295A discloses a differential cycloidal pin wheel reducer, mainly including a crankshaft, a housing, two groups of pin wheels and rollers, two cycloid gears and a driving motor. Its main feature is that: the differential speed of two groups of cycloidal pin wheel reducers with different numbers of teeth is used to achieve speed reduction, wherein the first stage pin wheel is fixed, the two cycloid gears are fixedly connected, share the same crankshaft, and the second stage pin wheel is the output. It mainly realizes a large reduction ratio while ensuring the output rigidity. However, the fatal problem is that the asymmetric structure is used on the high-speed side, and the unbalanced mass of the asymmetric structure is large, which leads to a large vibration of the reducer when the high-speed input is used, so it is not suitable for high-speed robot joints.

[0004] At present, the Chinese invention patent with publication number CN113565932A discloses a cycloidal planetary gear reducer, which adopts a symmetrical cycloidal ball reduction of a one-stage harmonic reducer and a one-stage planetary gear reduction. It realizes the effect similar to that of an RV reducer through cascade, while ensuring the running stability of the reducer. However, in the cycloidal reduction link, there is a large sliding friction between the steel ball and its matching parts, which greatly limits the rated input speed of the reducer, and the point contact of the steel ball also greatly limits the input torque of the reducer. SUMMARY

[0005] The present application proposes a thin cycloidal pin wheel reducer, which aims to overcome the deficiencies of the mobile robot joint reducer in the prior art, mainly the problems of the joint reducer in terms of load capacity, and improve the energy density of the joint reducer.

[0006] The above technical problems of the present application are mainly solved by the following technical scheme:

[0007] The utility model relates to a thin cycloidal speed reducer, characterized in that it comprises an input eccentric generator, a disc type cycloidal speed reduction structure, a mounting structure and a rear drive motor.

[0008] The input eccentric generator is provided with two groups of multiple eccentric generating bearings which are co-circular, and the centers of the eccentric generating bearings in each group are offset from the rotation center by an eccentric distance,

[0009] The disc type cycloidal speed reduction structure comprises a cycloidal disc, peripheral rollers, roller mounting pins, mounting pin fixing flange rings, output load bearings and output load bearing retaining rings. The cycloidal discs are symmetrically arranged to offset the centrifugal force of the eccentric motion of the cycloidal discs and simultaneously output torque outward.

[0010] The two groups of eccentric generating bearings act on the two cycloidal discs respectively, the input eccentric generator rotates around its geometric center to generate eccentric harmonic to drive the disc type cycloidal speed reduction structure to realize the speed reduction function. The peripheral rollers of the disc type cycloidal speed reduction structure are one more in number than the teeth of the cycloidal discs.

[0011] The mounting structure realizes the use, installation and torque output of the speed reducer.

[0012] The rear drive motor is mounted through the motor mounting flange hole on the input eccentric generator and is fixed through a plurality of penetrating structural assembly screws and a motor mounting plate mounted on the outer ring flange.

[0013] Further, the input eccentric generator comprises mounting flange plates, eccentric generating bearing mounting pins, eccentric generating bearings and a plurality of first gaskets. The eccentric generating bearing mounting pins are fixed at both ends to the mounting flange plates on the upper and lower sides respectively, and the eccentric generating bearings and the first gaskets are mounted on the eccentric generating bearing mounting pins. The eccentric generating bearings are divided into two groups and are symmetrically installed upside down, are co-circular respectively, and are adjusted in height by the first gaskets so that the flange edges of the two groups of eccentric generating bearings are located at the same height.

[0014] Further, the disc type cycloidal speed reduction structure comprises two cycloidal discs, a plurality of roller mounting pins, peripheral rollers corresponding in number to the roller mounting pins, an upper mounting pin fixing flange ring and a lower mounting pin fixing flange ring. The roller mounting pins are fixed at both ends to the upper mounting pin fixing flange ring and the lower mounting pin fixing flange ring respectively, the peripheral rollers are mounted on the mounting pins and are tangentially matched with the cycloidal discs to form the rotation space of the cycloidal discs, the cycloidal discs are mounted between the upper mounting pin fixing flange ring and the lower mounting pin fixing flange ring, and the output load bearings are arranged in the through holes in the cycloidal discs to simultaneously and tangentially act on the two cycloidal discs for outputting torque outward.

[0015] Further, the flange edge of the cycloid disc eccentricity generating bearing is used to separate two cycloid discs, and the inner hole of the cycloid disc is tangent to the flange edge of the cycloid disc eccentricity generating bearing.

[0016] Further, the mounting structure comprises an output flange ring, a mounting flange ring and an output bearing.

[0017] The output flange ring is mounted on the inner side of the output bearing, and has output flange threaded holes for outputting torque outwardly; the mounting flange ring is mounted on the outer side of the output bearing, and has mounting flange threaded holes and assembly flange threaded holes; the mounting flange threaded holes are used for mounting a speed reducer, and the assembly flange threaded holes are used for fixedly connecting with a disc cycloid pin gear speed reduction structure.

[0018] Further, the torque output screw and the structure assembly screw are further included, the output flange ring has two groups of threaded holes in a certain number, one group of output flange threaded holes is used for mounting an output structure, and the other group of threaded holes is used for mounting torque output screws, the other end of the torque output screw penetrates through the output bearing; the structure assembly screw penetrates through the mounting flange ring, the upper side mounting pin fixed flange ring and the lower side mounting pin fixed flange ring in sequence.

[0019] Therefore, compared with the prior art, the present application has the following advantages:

[0020] 1. High transmission efficiency and long service life. In the whole structure, only the peripheral ceramic rollers and ceramic roller mounting pins are in sliding friction, but the special ceramic has excellent self-lubricating and wear-resistant properties. In addition, all torque transmission combinations are fixed combinations or rolling combinations, and the rolling friction is much smaller than the sliding friction, which greatly improves the working efficiency of the speed reducer. At the same time, the rolling wear is also small, which improves the working life of the speed reducer.

[0021] 2. High input rotational speed and high precision. The mechanism adopts a symmetrical input eccentric generator, which has less vibration at high speed compared with a traditional crankshaft. In addition, the cycloid disc adopts an ultra-thin design, which maximizes the cancellation of centrifugal force and reduces vibration. Therefore, it can realize a high-speed input of more than 10,000 revolutions per minute, improving the mobility of the robot joint. Compared with the traditional multi-stage planetary reducer, the assembly size chain is shorter, and there are only three relative motion connections, which can realize higher running precision under the same machining precision.

[0022] 3. Small size and high power density. The speed reducer adopts a flat design, which improves the rigidity and torque output capacity. The cycloid pin gear structure itself has the characteristics of high bearing capacity, and the present application uses symmetrical design to improve the input rotational speed, thereby improving the structural power. In the design case, under the condition of a mass of less than 175g and a thickness of about 16mm, a working performance of more than 600W and more than 30Nm is realized. BRIEF DESCRIPTION OF DRAWINGS

[0023] Appendix Figure 1 This is an isometric drawing of the present invention.

[0024] Appendix Figure 2 This is a cross-sectional view of the present invention.

[0025] Appendix Figure 3 This is an exploded view of the input eccentricity generator of the present invention.

[0026] Appendix Figure 4 This is a schematic diagram of the input eccentricity generator structure of the present invention.

[0027] Appendix Figure 5 This is an isometric view of a portion of the disc-type cycloidal pinwheel reduction structure of the present invention.

[0028] Appendix Figure 6 This is an exploded view of part of the disc-type cycloidal pinwheel reduction structure of the present invention.

[0029] Appendix Figure 7 This is an isometric view of the mounting structure of the present invention.

[0030] Appendix Figure 8 This is an exploded view of the mounting structure portion of the present invention.

[0031] Appendix Figure 9 This is a schematic diagram showing the tangency between the outer roller and the cycloidal wheel of the present invention.

[0032] In the attached image:

[0033] 1-Input eccentric generator; 2-Disc cycloidal pinwheel reducer structure; 3-Mounting structure; 4-Rear drive motor; 5-Torque input screw; 6-Motor mounting plate; 7-Mounting flange plate; 8-Eccentric generator bearing; 9-First gasket; 10-Eccentric generator bearing mounting pin; 11-Cycloidal wheel; 12-Copper column; 13-Outer roller; 14-Roller mounting pin; 15-Output bearing; 16-Second gasket; 17-Upper mounting pin fixing flange ring; 18-Lower mounting pin fixing flange ring; 19-Output bearing retaining ring; 20-Output bearing; 21-Output flange ring; 22-Third gasket; 23-Torque output screw; 24-Mounting flange ring; 25-Structural assembly screw. Detailed Implementation

[0034] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0035] Example:

[0036] The dimensional requirements and achieved performance of the speed reducer in this example are as follows:

[0037] The maximum diameter is 73mm, the thickness is 16mm, the weight is 175g, the reduction ratio is 23:1, the maximum input rotating speed is about 10000r / min, the maximum output torque is greater than 30Nm, the maximum output power is greater than 600W, and the efficiency is greater than 90%.

[0038] Examples are shown in the drawings Figure 1 and Figure 2 As shown in the drawings, a thin cycloidal pin wheel reducer of the application comprises a reducer body and a rear drive motor 4. The reducer body is composed of an input eccentric generator 1, a disc type cycloidal pin wheel reduction structure 2 and a mounting structure 3. The rear drive motor 4 is installed through the torque input screw 5 on the input eccentric generator, and is fixed through a plurality of penetrating structure assembly screws 25 and a motor mounting plate 6. The input eccentric generator 1 and the disc type cycloidal pin wheel reduction structure 2 are at the same horizontal height, the mounting structure 3 is located on the upper side of the disc type cycloidal pin wheel reduction structure 2, and the drive motor is located on the lower side of the disc type cycloidal pin wheel reduction structure 2.

[0039] The input eccentric generator 1, as shown in the structural explosion Figure 3 , comprises flange plates 7 on the upper and lower sides, six groups of eccentric generating bearing mounting pins 10 of different mounting modes, eccentric generating bearings 8 and a first gasket 9 combination. By appropriately selecting the gasket specifications, the flange edges of the eccentric generating bearings 8 in the six combinations of opposite mounting can be located at the same height, and the flange edges are used to separate two cycloid discs 11 to prevent friction. The end of the combination is fixed in the blind hole of the flange plate 7 on the upper and lower sides. The mounting modes of every two non-adjacent combinations are opposite, and the specific position structure is shown in Figure 4 . Every three non-adjacent combinations determine a circle, and the center of the circle has an offset amount relative to the rotation center. The offset directions of the centers of the two groups of combinations are opposite, and constitute the eccentric input structure required by the disc type cycloidal pin wheel reduction structure 2. The input eccentric generator 1 rotates around its geometric center to generate two symmetrical eccentric oscillations. The flange plate 7 has a fixing hole for mounting the motor, which is assembled with the motor through a screw, and at the same time realizes the fastening of the input eccentric generator 1. Compared with the traditional crankshaft mode, the input eccentric generator 1 only has a very small rotating unbalanced mass when rotating, which can ensure the stability of high-speed operation.

[0040] The disc type cycloidal pin wheel reduction structure 2, as shown in the axonometric view Figure 5 , the structural explosion diagram is shown in Figure 6As shown, it includes cycloid disc 11, copper column 12, peripheral roller 13, roller mounting pin 14, upper mounting pin fixing flange ring 17, lower mounting pin fixing flange ring 18, output bearing 15, output bearing retaining ring 19, second gasket 16. The input eccentric generator 1 is installed between the two cycloid discs 11 for generating eccentric motion. The roller mounting pin 14 is installed and fixed through the uniformly distributed holes on the upper mounting pin fixing flange ring 17 and the lower mounting pin fixing flange ring 18, the peripheral roller 13 is installed on the roller mounting pin 14, and the axial movement is limited by the upper mounting pin fixing flange ring 17 and the lower mounting pin fixing flange ring 18. Among them, the upper mounting pin fixing flange ring 17 has an inner stop structure, which also serves to fix the output bearing 20. The cycloid disc 11 is symmetrically arranged in the space surrounded by the peripheral roller 13, and the outer contour is tangent to the peripheral roller 13, like Figure 9 As shown, the inner center hole is tangent to the same three eccentric bearing 8 of the input eccentric generator 1, the copper column 12 is penetrated by the structural assembly screw 25, and is fixedly installed between the upper mounting pin fixing flange ring 17 and the lower mounting pin fixing flange ring 18, for keeping the movement space of the cycloid disc 11. The cycloid disc 11 has a plurality of uniformly distributed through holes for torque output, and the output bearing 15 is arranged in the hole, which is tangent to the two cycloid discs 11 at the same time, and converts the swing of the cycloid disc 11 into rotary motion. The output bearing 15 is provided with a second gasket 16 on both sides to ensure the stability of rotation and the matching position of the parts. The torque output screw 23 penetrates the output flange ring 21, the output bearing 15, the second gasket 16, and the output bearing retaining ring 19, and is fixed opposite to the output flange ring 21, and is fixed by a nut, and outputs torque outward. The output bearing retaining ring 19 improves the rigidity of the output structure. The peripheral roller 13 and the roller mounting pin 14 in the disc type cycloid pin wheel reduction structure 2 adopt ceramic ball design, which maximizes the volume of the pin wheel part, thereby maximizing the reduction ratio and improving the output torque. In this example, the structure part is only about 13mm, and has a torque output capacity of more than 30Nm. The cycloid disc has small mass, close installation, and small structure running vibration.

[0041] The mounting structure 3, the isometric view is as shown in Figure 7 The explosion view is as shown in Figure 8The output flange ring 21 is installed inside the output bearing 20, and has two sets of screw holes, one set of output flange screw holes for installing output structural parts, and the other set of torque output screw holes 23 for transmitting the torque generated by the cycloid disc 11. The output flange ring 21 is axially positioned by the third gasket 22 and the second gasket 16. The mounting flange ring 24 is installed outside the output bearing 20, and also has two sets of screw holes, one set for external installation, and the other set for fixing the cycloidal pin gear speed reduction structure 2 and installing the rear drive motor 4. The mounting flange ring 24 and the mounting pin fixing flange ring 17 are provided with a stop edge, which ensures the axial positioning of the output bearing 20.

[0042] The working process of the embodiment is as follows:

[0043] The rotational movement of the motor is transmitted to the input eccentric generator 1 through the torque input screw 5, and the input eccentric generator 1 is tangent to the two cycloid discs 11, respectively, to convert the rotational movement of the motor into the rotational swing of the cycloid discs 11. The convex teeth of the cycloid discs 11 are sunk in the grooves formed by the peripheral ceramic rollers 13, and the number of grooves is one more than the number of disc teeth. When the cycloid disc 11 rotates one circle, the cycloid disc 11 is offset by one position relative to the peripheral ceramic rollers 13, that is, the speed reduction effect is achieved, and the speed reduction ratio is equal to the number of disc teeth. The rotational swing of the cycloid disc is converted into rotational movement through the tangential cooperation with the output load bearing 15, which is fixedly connected with the output flange ring 21 to output torque outward.

[0044] The specific embodiments described herein are merely illustrative of the spirit of the present application. Those skilled in the art of the present application can make various modifications or supplements to the described specific embodiments or replace them with similar ways, without departing from the spirit of the present application or exceeding the scope defined by the appended claims.

Claims

1. A thin cycloidal pinwheel reducer, characterized in that: It includes an input eccentric generator, a disc-type cycloidal pinwheel reduction structure, a mounting structure, and a rear-mounted drive motor; among which, The input eccentricity generator has two sets of multiple eccentric bearings that are concentrically arranged, with the center of each set of bearings offset from the rotation center by an eccentric distance. The disc-type cycloidal pinwheel reduction structure includes a cycloidal wheel, outer rollers, roller mounting pins, mounting pin fixing flange ring, output bearing, and output bearing retaining ring; the cycloidal wheel is symmetrically arranged to counteract the centrifugal force of the eccentric motion of the cycloidal wheel, while simultaneously outputting torque outward; Two sets of eccentric bearings act on two cycloidal discs respectively. The input eccentric generator rotates around its geometric center to generate eccentric harmonics, which drive the disc-type cycloidal pinwheel reduction structure to achieve the deceleration function. The outer rollers of the disc-type cycloidal pinwheel reduction structure have one more tooth than the cycloidal disc. The mounting structure enables the installation and torque output of the speed reducer. The rear drive motor is mounted via a mounting flange plate on the input eccentricity generator and is fixed by a number of through torque input screws mounted on the mounting flange plate and the motor mounting plate.

2. The thin cycloidal pinwheel reducer according to claim 1, characterized in that, The input eccentric generator includes a mounting flange plate, an eccentric generating bearing mounting pin, an eccentric generating bearing, and several first gaskets. The two ends of the eccentric generating bearing mounting pin are fixed to the upper and lower mounting flange plates respectively. The eccentric generating bearing and the first gaskets are both mounted on the eccentric generating bearing mounting pin. The eccentric generating bearing is divided into two groups, installed symmetrically in opposite directions, and each group is circular. The installation height of the eccentric generating bearing is adjusted by the first gaskets so that the flange edges of the two groups of eccentric generating bearings are at the same height.

3. A thin cycloidal pinwheel reducer according to claim 2, characterized in that, The described disc-type cycloidal pinwheel reducer structure includes two cycloidal discs, several roller mounting pins, a number of peripheral rollers corresponding to the roller mounting pins, an upper mounting pin fixing flange ring, and a lower mounting pin fixing flange ring. The roller mounting pins are fixed at both ends to the upper and lower mounting pin fixing flange rings, respectively. Peripheral rollers are mounted on the mounting pins and tangentially engage with the cycloidal discs, forming the rotation space of the cycloidal discs. The cycloidal discs are mounted between the upper and lower mounting pin fixing flange rings. The cycloidal discs have evenly distributed through holes, and output bearings are installed within these through holes. These output bearings are tangential to both cycloidal discs and are used to output torque outwards.

4. A thin cycloidal pinwheel reducer according to claim 2, characterized in that, The flange of the cycloidal wheel eccentric bearing is used to separate the two cycloidal wheels, and the inner hole of the cycloidal wheel is tangent to the cycloidal wheel eccentric bearing.

5. A thin cycloidal pinwheel reducer according to claim 1, characterized in that, The mounting structure includes an output flange ring, a mounting flange ring, and an output bearing; An output flange ring with an output flange threaded hole is installed on the inner side of the output bearing to output torque outward. An installation flange ring with an installation flange threaded hole and an assembly flange threaded hole is installed on the outer side of the output bearing. The installation flange threaded hole is used to install the reducer, and the assembly flange threaded hole is used to fix the disc cycloidal pinwheel reducer structure.

6. A thin cycloidal pinwheel reducer according to claim 5, characterized in that, It also includes torque output screws and structural assembly screws. The output flange ring has two sets of several threaded holes. One set of output flange threaded holes is used to install output structural components, and the other set is the mounting hole for the torque output screw. The other end of the torque output screw passes through the output flange ring and the output bearing. The structural assembly screw passes through the mounting flange ring, the upper mounting pin fixing flange ring, and the lower mounting pin fixing flange ring in sequence.

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