CN110848364A

CN110848364A - Eccentric transmission device

Info

Publication number: CN110848364A
Application number: CN201911179979.2A
Authority: CN
Inventors: 王金星; 周超; 黄学梁; 毕宇康; 彭飞; 常虹; 揭军
Original assignee: Aerospace Science And Technology Intelligent Robot Co Ltd
Current assignee: Aerospace Science And Technology Intelligent Robot Co Ltd
Priority date: 2019-11-27
Filing date: 2019-11-27
Publication date: 2020-02-28

Abstract

The present disclosure provides an eccentric transmission device including an input shaft, a gear transmission device, a harmonic reducer, and an output shaft. The input shaft is rotatable about a first axis; the gear transmission device is provided with a multi-stage transmission gear; the harmonic reducer comprises a cam, a flexible gear and a rigid gear. The output shaft can rotate around a second axis, and the second axis and the first axis are in a position relation of a spatial non-coplanar straight line; the input shaft is connected with the output shaft through a gear transmission device and a harmonic reducer; the output shaft is coaxially and fixedly connected with the rigid wheel; the cam is coaxially and fixedly connected with one gear in the gear transmission device; the rotation of the input shaft is transmitted to the cam through the gear transmission device, and the cam transmits the rotation to the rigid wheel through the flexible wheel, so that the output shaft is driven to rotate. The transmission mechanism solves the application problems of high transmission precision, large reduction ratio, high torque capacity and small volume in a narrow space.

Description

Eccentric transmission device

Technical Field

The present disclosure relates to the field of mechanical transmissions, such as reducers, and more particularly to an eccentric transmission having an offset between an input shaft and an output shaft.

Background

The harmonic reducer is a new transmission technology generated in the 50 th century of the 20 th century along with the development of space science and aerospace technology. The transmission mechanism has the characteristics of simple structure, small volume, light weight, low noise, strong bearing capacity, high transmission precision and the like, and is widely applied to the fields of aviation, aerospace, navigation, bionic machinery, energy sources, radar communication, machine tools, automobiles and the like.

At present, the harmonic reducers in China form standardized and serialized products, related manufacturers are numerous, the application fields of the products are wide, and the harmonic reducers are mainly concentrated in the fields of robots, spaceflight, weaponry and the like. The harmonic speed reducer is mostly in single-stage gear transmission, the reduction ratio is generally 30-160, and the harmonic speed reducer is mainly applied in the form of a speed reducer complete machine.

In some special application fields limited by space, a servo system has the requirements of miniaturization and light weight on a transmission device, and the harmonic reducer with small volume, light weight and strong bearing capacity is combined with other transmission mechanisms in a component mode to be applied, so that the harmonic reducer is an effective solution and has wide application prospect. However, the application of the harmonic reducer in the form of a component relates to the problems of precision assembly and debugging of the harmonic gear, has higher technical threshold, has higher requirements on manufacturers, and is less in application at present.

Disclosure of Invention

To solve or at least alleviate at least one of the above technical problems, the present disclosure provides an eccentric transmission having an offset between an input shaft and an output shaft.

According to one aspect of the present disclosure, an eccentric transmission device includes:

an input shaft rotatable about a first axis;

the gear transmission device is provided with a multi-stage transmission gear;

the harmonic reducer comprises a cam, a flexible gear and a rigid gear; and

the output shaft can rotate around a second axis, and the second axis and the first axis are in a position relation of a spatial non-coplanar straight line; the input shaft is connected with the output shaft through the gear transmission device and the harmonic reducer;

the output shaft is coaxially and fixedly connected with the rigid wheel; the cam is coaxially and fixedly connected with one gear in the gear transmission device; the rotation of the input shaft is transmitted to the cam through the gear transmission device, and the cam transmits the rotation to the rigid wheel through the flexible wheel, so that the output shaft is driven to rotate.

According to at least one embodiment of the present disclosure, the cam is formed as a coaxial unitary structural component with one of the gears in the gear assembly.

According to at least one embodiment of the present disclosure, a flexible bearing is sleeved outside the cam, and the flexible gear is sleeved outside the flexible bearing; the outer wall of the flexible gear is provided with gear teeth;

the eccentric transmission device further comprises a shell, wherein a circular through hole is formed in the part, opposite to the flexible gear, of the shell, and first inner teeth are uniformly arranged on the inner wall of the whole circumference of the circular through hole; part of the gear teeth of the flexible gear are meshed with the first internal teeth.

According to at least one embodiment of the present disclosure, the flexible gear is elastically deformed into an elliptical shape by the cam, the gear teeth of both end portions of the major axis of the flexible gear are engaged with the first internal teeth, and the gear teeth of both end portions of the minor axis of the flexible gear are disengaged from the first internal teeth; the number of the gear teeth of the flexible gear is smaller than that of the first internal teeth.

According to at least one embodiment of the present disclosure, the rigid wheel is circumferentially disposed outside the flexible wheel; second inner teeth are uniformly arranged on the inner wall of the whole circumference of the rigid wheel; part of gear teeth of the flexible gear are meshed with the second internal teeth; the number of the gear teeth of the flexible gear is equal to that of the second internal teeth.

According to at least one embodiment of the present disclosure, the integral structural member is a hollow structure and coaxially sleeved outside the output shaft, and the integral structural member is supported on the output shaft through a bearing; the first end of the output shaft is supported on the shell through a bearing, and the second end of the output shaft coaxially penetrates through the rigid wheel and is relatively fixedly connected with the rigid wheel; the rigid wheel is supported on the end cover through a bearing.

According to at least one embodiment of the present disclosure, the gear transmission device includes:

the first bevel gear is coaxially fixed at one end of the input shaft;

a first intermediate shaft arranged in parallel with the output shaft; a second bevel gear and a first cylindrical gear are relatively and fixedly arranged on the first intermediate shaft; the second bevel gear is meshed with the first bevel gear;

a second intermediate shaft arranged in parallel with the output shaft; a second cylindrical gear and a third cylindrical gear are relatively and fixedly arranged on the second intermediate shaft; the second cylindrical gear is meshed with the first cylindrical gear; and

the fourth cylindrical gear is coaxially and fixedly connected with the cam; the fourth cylindrical gear is meshed with the third cylindrical gear.

According to at least one embodiment of the present disclosure, the eccentric transmission device further includes a motor having a driving shaft as the input shaft.

According to at least one embodiment of the present disclosure, the eccentric transmission device further includes a potentiometer connected to the output shaft for recording a rotation angle of the output shaft.

According to at least one embodiment of the present disclosure, the second bevel gear and the first spur gear are a coaxial, unitary structure; the second cylindrical gear and the third cylindrical gear are of a coaxial integrated structure.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the disclosure and together with the description serve to explain the principles of the disclosure.

FIG. 1 is a schematic illustration of the drive principle of an exemplary embodiment of the eccentric drive of the present disclosure.

FIG. 2 is a first cross-sectional structural schematic of an exemplary embodiment of an eccentric drive of the present disclosure.

FIG. 3 is a second cross-sectional structural schematic view of an exemplary embodiment of an eccentric transmission of the present disclosure.

Description of reference numerals:

1-a motor; 2-an output shaft; 3-a potentiometer; 4-a flange; 5-a first bearing; 6-a first gear; 7-a second gear; 8-a second bearing; 9-a third gear; 10-a first support shaft; 11-a third bearing; 12-a first bearing cap; 13-a fourth gear; 14-a fourth bearing; 15-fifth gear; 16-a fifth bearing; 17-a second support shaft; 18-a second bearing cap; 19-sixth gear; 20-a cam; 21-a compliant bearing; 22-a flexible gear; 23-output rigid wheel; 24-a sixth bearing; 25-a seventh bearing; 26-a positioning sleeve; 27-an eighth bearing; 28-ninth bearing; 29-a housing; 30-end cap.

Detailed Description

The present disclosure will be described in further detail with reference to the drawings and embodiments. It is to be understood that the specific embodiments described herein are for purposes of illustration only and are not to be construed as limitations of the present disclosure. It should be further noted that, for the convenience of description, only the portions relevant to the present disclosure are shown in the drawings.

It should be noted that the embodiments and features of the embodiments in the present disclosure may be combined with each other without conflict. The present disclosure will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

The application of the harmonic reducer in a component form at present relates to the problems of precision assembly and debugging of harmonic gears, has higher technical threshold, has higher requirements on manufacturers, and is less in application at present. Accordingly, the present disclosure is directed to a transmission structure combining a harmonic reducer and a gear transmission, and in an effort to solve or at least alleviate at least one of the above technical problems, an eccentric transmission having an offset between an input shaft and an output shaft is disclosed.

According to one aspect of the present disclosure, an eccentric transmission includes an input shaft, a gear transmission, a harmonic reducer, and an output shaft. The input shaft may rotate about a first axis; for use as an input for motion. The gear transmission device is provided with a multi-stage transmission gear; the target reduction ratio is achieved by designing different levels of gear ratios. The harmonic reducer comprises a cam, a flexible gear and a rigid gear. The cam is non-circular and can rotate around its own axis, for example, the outer contour of the cam is usually designed to be elliptical and rotates around the central axis of the ellipse. The flexible gear, namely the flexible gear is sleeved outside the cam, and the flexible gear can generate elastic deformation and generate deformation at different parts of the circumference along with the rotation of the cam. The rigid wheel, namely the rigid gear, is sleeved outside the flexible wheel, the rigid wheel is usually circular, the inner wall of the rigid wheel is provided with inner gear teeth, and the outer surface of the flexible wheel is provided with outer gear teeth for being meshed with the outer gear teeth of the rigid wheel. The transmission principle of the harmonic reducer is that a flexible bearing is assembled on a wave generator (namely a cam) to enable a flexible gear to generate controllable elastic deformation, and the flexible gear is meshed with a rigid gear to transmit motion and power. The output shaft can rotate around a second axis, and the second axis and the first axis are in a position relation of a spatial non-coplanar straight line; that is to say, the input shaft and the output shaft are eccentrically arranged, the included angle between the two axes can be set in a range of [0,90 ° ] according to a specific application environment, for example, the included angle can be 90 °, so that the output shaft deflects 90 ° in the direction relative to the input shaft, and the distance between the second axis and the first axis is the eccentric distance between the output shaft and the input shaft. The input shaft is connected with the output shaft through a gear transmission device and a harmonic reducer. It will be appreciated by those skilled in the art that the eccentricity and deflection angle between the output and input shafts can be accommodated by designing the number of stages of the drive gears of the gear transmission between the input and output shafts and the direction of the axes of rotation of the gears. The above-mentioned components can be arranged in a housing structure, i.e. the eccentric drive comprises a housing, for example, the housing is designed as a frame structure, and mounting holes or escape spaces are provided at the positions where the components are to be mounted.

The output shaft and the rigid wheel are coaxially and fixedly connected, namely, the rotation of the rigid wheel is synchronously transmitted to the output shaft to drive the output shaft to rotate. The cam is coaxially and fixedly connected with one gear in the gear transmission device. The gear transmission device is internally provided with a plurality of transmission gears which transmit the rotation of the input shaft downwards step by step, one of the gears is coaxially and fixedly connected with the cam, and the rotation of the gear transmission device is synchronously transmitted to the cam to drive the cam to rotate. The rotation of the input shaft is transmitted to the cam through the gear transmission device, the cam transmits the rotation to the rigid wheel through the flexible wheel, and the rigid wheel drives the output shaft to rotate.

The eccentric transmission device disclosed by the invention has the advantages that the cam in the harmonic reducer is coaxially and fixedly connected with one of the gears in the gear transmission device, the gear transmission device and the harmonic reducer are effectively combined together, and the eccentricity and the deflection angle between the output shaft and the input shaft can be adapted by setting the number of stages of the transmission gears of the input shaft and the gear transmission device and the direction of the rotation shafts of the gears. The advantages of large reduction ratio, small volume and strong bearing capacity of the harmonic reducer are obtained, the input motion direction and position and the output motion position of the transmission device can be offset adjusted, and the application problem of a transmission mechanism with high transmission precision, large reduction ratio, high torque capacity and small volume in a narrow space is effectively solved.

In one embodiment of the present disclosure, the cam is formed as a coaxial, unitary structural component with one of the gears in the gear assembly. The cam and one of the gears in the gear transmission can be integrally manufactured and molded during manufacturing to form a whole component, so that the structure of the gear transmission is simplified.

In one embodiment of the disclosure, a flexible bearing is sleeved outside the cam, and a flexible gear is sleeved outside the flexible bearing; the flexible bearing can generate elastic deformation synchronously with the flexible gear, and meanwhile, the friction force between the cam and the flexible gear is reduced. The outer wall of the flexible gear is provided with gear teeth, and the flexible gear is equivalent to a flexible external gear.

A shell of the eccentric transmission device is provided with an installation space for installing the flexible gear, a circular through hole is formed in the part of the shell, which is opposite to the flexible gear, and first inner teeth are uniformly arranged on the inner wall of the whole circumference of the circular through hole; the circular through hole corresponds to a fixed internal gear. The gear teeth of part of the flexible gear are meshed with the first internal teeth. The flexible gear has certain axial thickness in the axial direction, and has a part of gear teeth meshed with the first internal teeth on the axial thickness, and the other part of gear teeth is not meshed with the first internal teeth.

In one embodiment of the present disclosure, the flexspline is elastically deformed into an elliptical shape by the cam, having a major axis and a minor axis. Gear teeth at two end parts of a long shaft of the flexible gear are meshed with the first internal teeth, and gear teeth at two end parts of a short shaft of the flexible gear are disengaged from the first internal teeth; the number of the gear teeth of the flexible gear is smaller than that of the first internal teeth. Under the condition that the flexbile gear continuously produces elastic deformation along with the cam rotation, the major axis and the minor axis of flexbile gear rotate around the central line of flexbile gear, make the teeth of a cogwheel of flexbile gear mesh with first internal tooth and break away from the meshing in proper order in the circumferencial direction, because the teeth of a cogwheel number of flexbile gear is less than the number of first internal tooth, thereby every time the cam rotates a week, the flexbile gear just rotates the centre of a circle angle that the number of teeth that the relative casing of direction opposite with the cam rotation phase difference corresponds, thereby produce speed reduction.

In one embodiment of the present disclosure, the rigid wheel is disposed around the outside of the flexible wheel; the inner wall of the whole circumference of the rigid wheel is uniformly provided with second inner teeth. The rigid wheel corresponds to an internal gear. The gear teeth of the partial flexible gear are meshed with the second internal teeth; in the axial thickness direction of the flexible gear, a part of the gear teeth of the flexible gear is engaged with the second internal teeth. That is, the second internal teeth of the rigid gear and the first internal teeth of the circular through hole in the housing are respectively engaged with the gear teeth of a part of the flexible gear in the thickness direction of the flexible gear. The number of the gear teeth of the flexible gear is equal to the number of the second internal teeth, the meshing mode of the flexible gear and the rigid gear is similar to the meshing mode of the flexible gear and the shell, and the gear teeth of the flexible gear are equal to the number of the second internal teeth, so that the rigid gear and the flexible gear rotate synchronously.

In one embodiment of the present disclosure, an integral structural component formed by the cam and one of the gears in the gear transmission device is a hollow structure, and is coaxially sleeved outside the output shaft and can rotate relative to the output shaft. The integral structure part is supported on the output shaft through the bearing, the bearing is arranged between the integral structure part and the output shaft, the output shaft can be provided with a step surface, and the bearing is axially positioned through the step surface. The first end of the output shaft is supported on the shell through a bearing, and a bearing mounting hole for mounting the bearing is formed in the shell. The second end of the output shaft coaxially penetrates through the rigid wheel and is relatively fixedly connected with the rigid wheel; the two can be connected by a key or a pin. The rigid wheel is supported on the end cover through the bearing, the end cover is provided with a mounting hole for mounting the bearing, and the bearing is sleeved outside the rigid wheel.

In one embodiment of the present disclosure, the gear assembly includes a first bevel gear, a first countershaft, a second countershaft, and a fourth spur gear. The first bevel gear is coaxially fixed at one end of the input shaft and rotates synchronously with the input shaft. The first intermediate shaft is arranged in parallel with the output shaft. The first intermediate shaft is relatively fixedly provided with a second bevel gear and a first cylindrical gear, the second bevel gear and the first cylindrical gear can be connected onto the first intermediate shaft through keys, the first intermediate shaft is rotatably supported on the shell through a bearing, the bearing cover is detachably mounted on the shell positioned at one end of the first intermediate shaft for convenience of maintenance, and the bearing is supported on the bearing cover. The second bevel gear is meshed with the first bevel gear. The second intermediate shaft is arranged in parallel with the output shaft, a second cylindrical gear and a third cylindrical gear are fixedly arranged on the second intermediate shaft relatively, the second cylindrical gear and the third cylindrical gear can be connected to the second intermediate shaft through keys, and the second cylindrical gear is meshed with the first cylindrical gear. Similarly, the second intermediate shaft is rotatably supported in the housing by a bearing, and a bearing cover is detachably mounted on the housing at one end of the second intermediate shaft for maintenance, and the bearing is supported on the bearing cover. The fourth cylindrical gear is coaxially and fixedly connected with the cam; the fourth cylindrical gear is meshed with the third cylindrical gear. The rotation of the input shaft is transmitted step by step through the bevel gear and the cylindrical gear, and the rotation of the fourth cylindrical gear drives the cam to synchronously rotate.

In one embodiment of the present disclosure, the eccentric transmission further includes a motor, a drive shaft of the motor serving as an input shaft. This embodiment may be used to mount the robot arm as a module that drives the joint to rotate. The motor is installed outside the shell through the connecting piece, and the drive shaft of motor goes deep into the shell and is connected with the output shaft as the input shaft, through above-mentioned various embodiments, and the drive shaft of motor drives the output shaft and rotates. The radial or axial position of the motor is adjusted, or the position of the output shaft is moved up and down or left and right, so that the requirement of matching different eccentric interfaces can be met.

Further, the eccentric transmission device also comprises a potentiometer, and the potentiometer is connected with the output shaft and used for recording the rotation angle of the output shaft. The potentiometer may be mounted to the housing and connected to one end of the output shaft through an opening in the housing. The motor can adopt a servo electric motor, and the rotation angle of the output shaft is accurately controlled through the cooperation with the potentiometer.

Optionally, the second bevel gear and the first cylindrical gear can be manufactured into a coaxial integrated structure; the second cylindrical gear and the third cylindrical gear can be manufactured into a coaxial integrated structure. The integral structure referred to herein means that the two parts are formed as an integral member, and the two parts may be integrally formed at the time of manufacture, or the two parts may be separately manufactured and then combined to form an integral member. The embodiment can omit a connecting and positioning device of two components on the intermediate shaft, and simplify the structure of the whole eccentric transmission device.

The following description is made with reference to the accompanying drawings. Referring to a schematic diagram of a transmission principle of an exemplary embodiment of the eccentric transmission device of the present disclosure shown in fig. 1, the eccentric transmission device includes a motor 1, a first-stage gear reduction assembly, a second-stage gear reduction assembly, a third-stage gear reduction assembly, a harmonic reduction assembly, an output shaft 2, a housing 29, an end cover 30, and a potentiometer 3, and four stages of speed reduction are total. Wherein, two grade, three grade speed reduction subassemblies respectively contain a support shaft (being equivalent to the jackshaft), and the harmonic speed reduction subassembly includes cam 20, flexbile gear 22, output rigid wheel 23 and flexible bearing 21. In the working process of the eccentric transmission device, the motor 1 drives the primary gear speed reducing component to rotate to form primary speed reduction. The second gear 7 and the third gear 9 are combined gears and are fixedly connected together, and the third gear 9 and the fourth gear 13 form two-stage speed reduction; the fourth gear 13 and the fifth gear 15 are combined gears and are fixedly connected together, and the fifth gear 15 and the sixth gear 19 form three-stage speed reduction; the sixth gear 19 is fixedly connected with a cam 20 in the harmonic speed reducing assembly to drive the harmonic speed reducing assembly to form four-stage speed reduction, and the final speed reducing motion is output by an output shaft.

The structure and operation of one embodiment of the present disclosure will be described in detail below with reference to the schematic cross-sectional structure of an exemplary embodiment of the eccentric transmission of the present disclosure shown in fig. 2 and 3.

In one embodiment of the present disclosure, the eccentric transmission device includes a motor 1 used as a motor, an output shaft 2, a potentiometer 3, a flange 4, a first bearing 5, a first gear 6, a second gear 7, a second bearing 8, a third gear 9, a first support shaft 10 (corresponding to a first intermediate shaft), a third bearing 11, a first bearing cover 12, a fourth gear 13, a fourth bearing 14, a fifth gear 15, a fifth bearing 16, a second support shaft 17 (corresponding to a second intermediate shaft), a second bearing cover 18, a sixth gear 19, a cam 20, a flexible bearing 21, a flexible gear 22, an output rigid gear 23, a sixth bearing 24, a seventh bearing 25, a positioning sleeve 26, an eighth bearing 27, a ninth bearing 28, a housing 29, and an end cover 30. The housing 29, the end cover 30, the flange 4, the first gear 6, the second gear 7, the first support shaft 10, the third gear 9, the first bearing cover 13, the fourth gear 13, the fifth gear 15, the second support shaft 17, the second bearing cover 18, the sixth gear 19, the cam 20, the flexible bearing 21, the flexspline 22, the output rigid gear 23, the output shaft 2 and the positioning sleeve 26 are all made of high-performance alloy structural steel materials. The housing 29 has a frame structure, and the outer dimensions are within 50mm × 50mm × 30 mm. The first gear 6 and the second gear 7 are both bevel gears, the shaft intersection angle of the first gear 6 and the second gear 7 is 90 degrees, and the number of teeth of the second gear 7 is more than that of the first gear 6.

The output shaft (being equivalent to the drive shaft) of motor 1 passes through the shaft hole of seting up on flange 4 and with the coaxial casing 29 that stretches into in of shaft hole, motor 1 passes through screw fixed connection with flange 4, flange 4 is towards one side of casing 29 (with the motor output shaft homonymy) and the cooperation of the motor mounting hole on the casing 29, fix on the casing 29 lateral wall through the screw, first gear 6 adopts bevel gear, bevel gear's axial hollow structure, the output shaft of motor 1 wears to establish in the axial hollow structure of first gear 6, the terminal surface of motor output shaft flushes with the terminal surface of first gear 6, first gear 6 passes through round pin fixed connection with the motor output shaft, be equivalent to fixing first gear 6 at the tip of motor output shaft. The first gear wheel 6 is supported on the flange 4 by means of a first bearing 5.

The second gear 7 and the third gear 9 are fixedly connected with the first support shaft 10, and the second gear 7 adopts a bevel gear. One end of the first support shaft 10 is supported on the housing 29 through the second bearing 8, the other end is supported on the first bearing cover 12 through the third bearing 11, the first bearing cover 12 is fitted to the housing 29 and fixed by screws, and the second gear 7 is engaged with the first gear 6.

The fourth gear 13 and the fifth gear 15 are fixedly connected with the second supporting shaft 17, one end of the second supporting shaft 17 is supported on the shell 29 through the fourth bearing 14, the other end of the second supporting shaft is supported on the second bearing cover 18 through the fifth bearing 16, the second bearing cover 18 is matched with the shell 29 and fixed through screws, the fourth gear 13 is meshed with the third gear 9, and the number of teeth of the fourth gear 13 is greater than that of the third gear 9. The sixth gear 19 is formed as an integral structure with the cam 20, and is supported on the output shaft 2 by an eighth bearing 27 and a ninth bearing 28, and the sixth gear 19 meshes with the fifth gear 15, and the number of teeth of the sixth gear 19 is larger than that of the fifth gear 15. The third gear 9, the fourth gear 13, the fifth gear 15 and the sixth gear 19 are all cylindrical gears.

The housing 29 has a bearing hole in the inner sidewall (a sidewall near the flexspline), and a bearing cap mounting hole in the outer sidewall (a sidewall near the potentiometer) coaxial with the bearing hole in the housing. The first support shaft 10 and the second support shaft 17 are both of a stepped shaft structure, and shaft shoulders are arranged at two ends of the stepped shaft structure. Among them, one end of the first support shaft 10 is supported on the housing 29 through the second bearing 8, the other end is supported on the first bearing cover 12 through the third bearing 11, the second support shaft 17 is supported on the housing 29 through the fourth bearing 14, and the other end is supported on the second bearing cover 18 through the fifth bearing 16.

The cam 20 and the flexible bearing 21 constitute a wave generator, and the flexible gear 22 is engaged with internal teeth (corresponding to first internal teeth) provided in the housing 29, while the flexible gear 22 is engaged with internal teeth (corresponding to second internal teeth) of the output rigid gear 23. That is, the flexspline 22 engages both the output rigid spline 23 and the housing 29. The shaft part of one end (the right end in fig. 3) of the output shaft 2 is fixedly combined with the inner hole of the output rigid wheel, the other end of the output shaft 2 is supported on a shell 29 through a seventh bearing 25, one end connected with the output rigid wheel is supported on an end cover 30 through a sixth bearing 24 arranged outside the output rigid wheel, and the end cover 30 is fixedly connected with the shell 29 through screws.

In the working process of the eccentric transmission device, the motor 1 provides power to drive the first gear 6 fixedly connected with the output shaft of the motor 1, the power is transmitted to the second gear 7 meshed with the first gear to form primary speed reduction, and the power transmission motion direction deflects by 90 degrees because the intersection angle of the axes of the first gear 6 and the second gear 7 is 90 degrees (vertical to each other). The second gear 7 transmits power to a first supporting shaft 10 fixedly connected with the second gear, the first supporting shaft 10 serves as an output part of primary speed reduction to transmit the power to a third gear 9 fixedly connected with the first supporting shaft, the third gear 9 is meshed with a fourth gear 13 to form secondary speed reduction, the axis of the third gear 9 is parallel to the axis of the fourth gear 13, and the power transmission movement direction is unchanged. The fourth gear 13 transmits power to a second supporting shaft 17 fixedly connected with the second supporting shaft, the second supporting shaft 17 serves as an output part of two-stage speed reduction and transmits power to a fifth gear 15 fixedly connected with the second supporting shaft, the fifth gear 15 is meshed with a sixth gear 19 to form three-stage speed reduction, the axis of the fifth gear 15 is parallel to the axis of the sixth gear 19, and the power transmission movement direction is unchanged. The sixth gear 19 transmits the power to the cam 20 fixedly connected with the sixth gear, the cam 20 and the flexible bearing 21 form a wave generator, the rotation of the wave generator forces the flexible gear 22 to generate elastic deformation and take an elliptical shape, the flexible gears 22 at two ends of the major axis of the wave generator are completely meshed with the gear teeth of the shell 29, the flexible gears 22 at two ends of the minor axis of the wave generator are completely separated from the gear teeth of the shell, and the area between the major axis and the minor axis is in a meshed or meshed state. When the wave generator is continuously rotated, the flexible gear 22 and the gear teeth of the shell 29 are in a meshing, complete meshing, meshing and complete disengaging cycle process. Because the number of teeth of the flexible gear 22 is 2 less than that of the teeth of the shell 29 (or the flexible gear 22 is set to be 3 or other numerical values according to the reduction ratio), the motion process is staggered-tooth motion, the wave generator rotates for a circle, the flexible gear 22 rotates for an angle of two teeth in opposite directions, four-stage speed reduction with larger reduction ratio is realized, the axis of the sixth gear 19 is parallel to the axis of the cam 20, and the power transmission motion direction is unchanged. The flexible gear 22 is meshed with the gear teeth of the shell 29 and simultaneously meshed with the output rigid gear 23, the flexible gear 22 and the output rigid gear 23 have the same tooth number and constant speed ratio, the output rigid gear 23 is fixedly connected with the output shaft 2 to drive the output shaft 2 to rotate so as to complete power output, and the axis of the output shaft 2 is vertical to the axis of the output shaft (serving as an input shaft of an eccentric transmission device) of the motor 1, so that the power input movement direction deflection is finally formed. In the working process of the transmission device, the axes of the first support shaft 10 and the second support shaft 17 are parallel to the axis of the output shaft 2 and are vertical to the axis of the output shaft of the motor 1, and the axis of the output shaft of the motor 1 and the axis of the output shaft 2 are not coplanar (in a non-coplanar linear relationship), but offset at a certain distance. The positions of the output shaft of the motor 1 and the output shaft 2 are adjusted, so that the power transmission requirements under different interfaces can be met.

From the above, the eccentric transmission device disclosed by the invention has the advantages of large reduction ratio, small volume and strong bearing capacity of the harmonic reducer, and can adapt to the conditions of deflection and offset of the input motion direction and position, the output motion direction and position of the transmission device. The application problems of high transmission precision, large reduction ratio, high torque capacity and small volume of the transmission mechanism in a narrow space are effectively solved.

In the description herein, reference to the description of the terms "one embodiment/mode," "some embodiments/modes," "example," "specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment/mode or example is included in at least one embodiment/mode or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to be the same embodiment/mode or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments/modes or examples. Furthermore, the various embodiments/aspects or examples and features of the various embodiments/aspects or examples described in this specification can be combined and combined by one skilled in the art without conflicting therewith.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

It will be understood by those skilled in the art that the foregoing embodiments are merely for clarity of illustration of the disclosure and are not intended to limit the scope of the disclosure. Other variations or modifications may occur to those skilled in the art, based on the foregoing disclosure, and are still within the scope of the present disclosure.

Claims

1. An eccentric transmission, comprising:

an input shaft rotatable about a first axis;

the gear transmission device is provided with a multi-stage transmission gear;

the harmonic reducer comprises a cam, a flexible gear and a rigid gear; and

2. An eccentric transmission according to claim 1, characterized in that the cam is formed as a coaxial, one-piece structural part with one of the gears in the gear transmission.

3. The eccentric transmission device according to claim 2, wherein a flexible bearing is sleeved outside the cam, and the flexible gear is sleeved outside the flexible bearing; the outer wall of the flexible gear is provided with gear teeth;

4. The eccentric transmission device according to claim 3, wherein the flexible gear is elastically deformed into an elliptical shape by the cam, and the gear teeth of both end portions of the major axis of the flexible gear are engaged with the first internal teeth and the gear teeth of both end portions of the minor axis of the flexible gear are disengaged from the first internal teeth; the number of the gear teeth of the flexible gear is smaller than that of the first internal teeth.

5. The eccentric transmission of claim 4, wherein the rigid wheel is disposed around the outside of the flexible wheel; second inner teeth are uniformly arranged on the inner wall of the whole circumference of the rigid wheel; part of gear teeth of the flexible gear are meshed with the second internal teeth; the number of the gear teeth of the flexible gear is equal to that of the second internal teeth.

6. The eccentric transmission of claim 5, wherein said unitary structural member is hollow and coaxially disposed about said output shaft, said unitary structural member being supported by said output shaft via a bearing; the first end of the output shaft is supported on the shell through a bearing, and the second end of the output shaft coaxially penetrates through the rigid wheel and is relatively fixedly connected with the rigid wheel; the rigid wheel is supported on the end cover through a bearing.

7. An eccentric transmission according to any of claims 1 to 6, characterized in that the gear transmission comprises:

the first bevel gear is coaxially fixed at one end of the input shaft;

8. The eccentric transmission of claim 7, further comprising a motor having a drive shaft as the input shaft.

9. The eccentric drive of claim 7, further comprising a potentiometer coupled to the output shaft for recording the angle of rotation of the output shaft.

10. The eccentric transmission of claim 7, wherein said second bevel gear and said first spur gear are of a coaxial, unitary construction; the second cylindrical gear and the third cylindrical gear are of a coaxial integrated structure.