CN111946796A

CN111946796A - Multistage gear drive's harmonic speed reducer ware and robot

Info

Publication number: CN111946796A
Application number: CN202010682771.9A
Authority: CN
Inventors: 田珍珍; 程中甫; 谷甲甲; 张皓; 杨繁荣; 郭霜
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2020-07-15
Filing date: 2020-07-15
Publication date: 2020-11-17

Abstract

The invention belongs to the technical field of harmonic reducers, and particularly relates to a harmonic reducer driven by multiple gears and a robot, wherein the harmonic reducer comprises: the primary planetary gear transmission mechanism comprises a wave generator with an internal gear and an input shaft penetrating through the wave generator, wherein the input end of the input shaft is connected with a driving motor, and the output end of the input shaft is provided with a sun gear; a planetary gear set is arranged between the sun gear and an internal gear of the wave generator and is simultaneously meshed with the sun gear and the internal gear of the wave generator; the second-order harmonic gear transmission mechanism comprises a flexible gear, and the flexible gear is sleeved on the outer side wall of the wave generator; the invention can effectively enlarge the reduction ratio range of the reducer and enhance the bearing capacity of the whole reducer by adding a primary planetary gear transmission in the wave generator.

Description

Multistage gear drive's harmonic speed reducer ware and robot

Technical Field

The invention belongs to the technical field of harmonic reducers, and particularly relates to a harmonic reducer driven by multiple gears and a robot.

Background

The harmonic reducer has the characteristics of small volume, large reduction ratio, multiple meshing teeth, stable transmission, high bearing capacity, high transmission precision and the like. Therefore, the robot is widely applied to aerospace, military, industrial robots and the like. The harmonic reducer is mainly composed of three parts, namely a wave generator, a flexible gear and a rigid gear. Because the harmonic drive mainly depends on the wave generator with an elliptical shaft to force the flexible gear to generate elastic deformation and then to be meshed with the rigid gear for transmission, because the flexible gear is of a thin-wall structure and has small modulus, more teeth and the like, the tooth part and the thin wall of the flexible gear 2 are easy to break in the transmission process, and the bearing capacity and the service life of the speed reducer are directly influenced. When the harmonic speed reducer ware of same volume need be used great reduction ratio, traditional reduction gear structure can only be realized through increasing rigid wheel, flexbile gear number of teeth, can lead to the tooth of rigid flexible gear meshing to add for a short time, has increased the design degree of difficulty and processing cost.

Patent No. CN 109723799 a discloses a speed reduction system in which a planetary gear unit, a harmonic unit, and a motor unit are integrated in an axial direction, and although a reduction ratio can be increased, the axial dimension thereof is increased, and the assembly space when the speed reduction structure is used is increased. The speed reducer of the combined mode is applied to robots and the like, the size and the weight of the whole machine are undoubtedly increased, and the speed reducer is contrary to the pursuit direction of light weight and miniaturization in the industry at present.

The present invention has been made in view of the above circumstances.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a harmonic reducer driven by multiple gears, which is characterized by comprising the following components:

the primary planetary gear transmission mechanism comprises a wave generator with an internal gear and an input shaft penetrating through the wave generator, wherein the input end of the input shaft is connected with a driving motor, and the output end of the input shaft is provided with a sun gear; a planetary gear set is arranged between the sun gear and the internal gear of the wave generator and is simultaneously meshed with the sun gear and the internal gear of the wave generator;

the second-order harmonic gear transmission mechanism comprises a flexible gear, and the flexible gear is sleeved on the outer side wall of the wave generator;

in the operation process of the harmonic reducer, the primary planetary gear transmission mechanism transmits power input by the input shaft to the wave generator through the sun gear and the planetary gear set, and then the wave generator transmits the power to the secondary harmonic gear transmission mechanism and the flexible gear outputs the power.

Further optionally, the sun gear is fixedly engaged with the input shaft, and rotation of the input shaft drives rotation of the sun gear.

Further optionally, the wave generator is in an elliptical ring structure, the internal gears are uniformly distributed along the circumferential direction of the inner wall of the elliptical ring, and the planetary gear sets are located between the inner wall of the elliptical ring structure and the sun gear and are simultaneously meshed with the sun gear and the internal gears.

Further optionally, the sun gear is disposed at the center of the elliptical ring structure through the input shaft, and the planetary gear set includes a plurality of planetary gears evenly distributed along a circumferential direction of the sun gear.

Further optionally, there are two planet gears, and the two planet gears are symmetrically distributed along the radial direction of the sun gear.

Further optionally, the harmonic reducer further comprises a rigid wheel and a rigid bearing, wherein the rigid wheel is sleeved on the outer side wall of the flexible wheel and is matched with the flexible wheel teeth; the rigid bearing comprises a rigid bearing inner ring and a rigid bearing outer ring, the rigid wheel is connected with the rigid bearing inner ring to serve as a fixed part of the harmonic reducer, and the flexible wheel is connected with the rigid bearing outer ring to serve as an output part of the harmonic reducer.

Further optionally, the primary planetary gear transmission mechanism further comprises a planet carrier, the planet carrier comprises a planet carrier chassis, an output end of the input shaft penetrates through the planet carrier chassis and then extends into the wave generator, and the input shaft and the planet carrier chassis are arranged in a clearance;

the planetary gear set comprises a plurality of planetary gears, a plurality of planetary gear installation positions are arranged on the planet carrier chassis, and the plurality of planetary gears are rotatably arranged on the plurality of planetary gear installation positions and are simultaneously meshed with the sun gear and the internal gear of the wave generator.

Further optionally, the planet gear mounting position is a connecting shaft formed by extending the planet carrier chassis towards the inside of the wave generator, and the planet gear is rotatably connected with the connecting shaft.

Further optionally, the planet carrier chassis is disc-shaped, and the size of the planet carrier chassis is larger than that of the wave generator;

the planet carrier also comprises a planet carrier side wall which is arranged around the planet carrier chassis, and the wave generator is arranged in a cavity formed by the planet carrier chassis and the planet carrier side wall; the planet carrier lateral wall with form certain clearance between the lateral wall of wave generator, the flexbile gear is located establish in the clearance and the cover establish on the lateral wall of wave generator with the lateral wall fixed coordination of wave generator, the planet carrier lateral wall is fixed on the rigid gear, and the rigid gear cover is established the outside and the cooperation of flexbile gear tooth of flexbile gear.

Further optionally, the end surface of the side wall of the planet carrier comprises an outer end surface and an inner end surface from outside to inside, the inner end surface is arranged in a sinking manner, a certain height difference is formed between the inner end surface and the outer end surface, and the rigid wheel is fixed on the inner end surface.

Further optionally, a height difference between the outer end surface and the inner end surface is less than or equal to a thickness of the rigid wheel;

and/or the width of the inner end surface is smaller than or equal to the width of the rigid wheel.

The invention also provides a robot with the harmonic reducer.

After adopting the technical scheme, compared with the prior art, the invention has the following beneficial effects:

according to the invention, by designing the wave generator with the internal gear, the primary planetary gear transmission is added, and the reduction ratio range of the speed reducer can be effectively enlarged; when the motor is used for a conventional robot, the effect of reducing the load torque of the motor is achieved by increasing the speed reduction of the primary planetary gear, a smaller motor can be selected, the load inertia is reduced, and the light weight is realized; because the primary planetary gear transmission is designed in the wave generator, the axial size of the whole machine can be effectively reduced and the production and processing cost can be reduced while the reduction ratio is increased.

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention, are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention without limiting the invention to the right. It is obvious that the drawings in the following description are only some embodiments, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:

FIG. 1: the integral structure diagram of the harmonic reducer of the embodiment of the invention;

FIG. 2: is a cross-sectional view of fig. 1;

FIG. 3: is a perspective view of a primary planetary gear drive embodying the present invention;

FIG. 4: is a plan view of a primary planetary gear transmission embodying the present invention;

FIG. 5: is a second harmonic gear drive schematic diagram of an embodiment of the invention.

Wherein: 1. a wave generator; 2. a flexible gear; 3. a rigid wheel; 4. a rigid bearing inner race; 5. a rigid bearing outer race; 6. an input shaft; 7. a sun gear; 8. a planetary gear; 11. an internal gear; 91. a planet carrier chassis; 911. an installation position; 921. an outer end face; 922. an inner end surface; 9221. and a screw hole.

It should be noted that the drawings and the description are not intended to limit the scope of the inventive concept in any way, but to illustrate it by a person skilled in the art with reference to specific embodiments.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and the following embodiments are used for illustrating the present invention and are not intended to limit the scope of the present invention.

In the description of the present invention, it should be noted that the terms "inside", "outside", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, which are only for convenience in describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and operate, and thus, should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," "contacting," and "communicating" are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

At present, the general transmission mode of the harmonic reducer is as follows: the wave generator 1 is driven by a motor to be used as the input of the whole machine, the rigid wheel 3 is connected with the rigid bearing inner ring 4 to be used as the fixed part of the whole machine, and the flexible wheel 2 is connected with the rigid bearing outer ring 5 to be used as the output part of the whole machine. In a particular embodiment the rigid bearing inner ring 4 and the rigid bearing inner ring 5 are crossed roller bearings. Because the mode is that the flexible gear 2 is continuously elastically deformed to be meshed with the rigid gear 3 for torque transmission, the requirement on the material performance of the flexible gear 2 is high, and the rigidity of the whole machine is limited due to the special transmission motion. In view of the above problems, the present embodiment provides a multi-stage gear-driven harmonic reducer, as shown in fig. 1 to 4, including a first-stage planetary gear transmission mechanism and a second-stage harmonic gear transmission mechanism.

As shown in fig. 3 and 4, the primary planetary gear transmission mechanism includes a wave generator 1 with an internal gear 11 and an input shaft 6 penetrating the wave generator 1, wherein an input end of the input shaft 6 is connected with a driving motor, and an output end is provided with a sun gear 7; one way of implementation is that the output end of the input shaft 6 is integrally formed with the sun gear 7, and the other way of implementation is that the sun gear 7 is sleeved on the output end of the input shaft 6 and is fixedly connected with the input shaft. A planetary gear set is arranged between the sun gear 7 and the internal gear 11 of the wave generator 1, and is simultaneously meshed with the sun gear 7 and the internal gear 11 of the wave generator 1; preferably, the wave generator 1 is in an elliptical ring structure, the internal gears 11 are uniformly distributed along the circumferential direction of the inner wall of the elliptical ring, the sun gear 7 is arranged at the center of the elliptical ring structure through the input shaft 6, and the planetary gear set is positioned between the inner wall of the elliptical ring structure and the sun gear 7 and is simultaneously meshed with the sun gear 7 and the internal gear 11. As shown in fig. 1 and 2, the second harmonic gear drive includes a flexible gear 2 with an outer ring gear and a rigid gear 3 with an inner ring gear; the flexible gear 2 and the rigid gear 3 are sequentially sleeved on the outer side wall of the wave generator 1 from inside to outside;

in the operation process of the harmonic reducer, the primary planetary gear transmission mechanism transmits power input by the input shaft 6 to the wave generator 1 through the sun gear 7 and the planetary gear set, and then the wave generator 1 transmits the power to the secondary harmonic gear transmission mechanism and the power is output by the flexible gear 2.

In the embodiment, the primary planet gear 8 is added in the wave generator 1 for transmission, so that the reduction ratio range of the speed reducer can be effectively expanded, and the bearing capacity of the whole speed reducer is enhanced; when the motor is used for a conventional robot, the effect of reducing the load torque of the motor is achieved by increasing the speed reduction of the primary planetary gear, a smaller motor can be selected, the load inertia is reduced, and the light weight is realized; because the primary planetary gear transmission is designed in the wave generator, the axial size of the whole machine can be effectively reduced and the production and processing cost can be reduced while the reduction ratio is increased.

In the transmission of the primary planetary gear 8, the sun gear 7 is connected with the motor through the input shaft 6, the sun gear 7 is fixedly matched with the input shaft 6, and the input shaft 6 rotates to drive the sun gear 7 to rotate to serve as an input part of the whole machine.

The planetary gear 8 is used as an intermediate transmission structure to be meshed with the sun gear for transmission and simultaneously transmit power to the wave generator 1 with the inner gear ring. In the primary planetary gear 8 transmission, a sun gear 7 is an input part, and a wave generator 1 with an inner gear ring is used as an output part of the primary transmission; as shown in fig. 5, in the second harmonic gear drive, the elliptical wave generator 1 is an input portion, the rigid gear 3 is a fixed portion, and the flexible gear 2 is an output portion. When in transmission, the output part wave generator 1 of the first stage is used as the input part of the second stage, because the wave generator 1 is an elliptical shaft with a long shaft and a short shaft or a shaft with other irregular shapes, the wave generator can force the thin-wall flexible gear 2 to generate corresponding deformation, and further to be meshed with the rigid gear 3 with the tooth number difference, and because the rigid gear 3 is fixed, the rigid gear 3 reacts on the flexible gear 2 to enable the flexible gear 2 to output power. The flexible gear 2 and the rigid gear 3 have the same tooth pitch but different tooth numbers, the wave generator 1 forces the teeth of the flexible gear 2 at the long axis to be engaged in and out relative to the teeth of the rigid gear 3, and a certain amount of tooth number difference exists between the teeth of the flexible gear 2 and the teeth of the rigid gear 3, so that the effect of differential gear speed reduction is achieved.

Further alternatively, as shown in fig. 3 and 4, the primary planetary gear transmission mechanism further includes a planet carrier fixed to the rigid gear 3. The planet carrier is connected with the rigid gear 3 to be used as a fixed part of the whole harmonic reducer, the wave generator 1 with an inner gear ring is used as an output part of the first-stage transmission and an input part of the second-stage transmission, and the flexible gear 2 is used as an output part of the second-stage transmission.

The planet carrier includes planet carrier chassis 91, and the output of input shaft 6 passes in planet carrier chassis 91 back stretches into wave generator 1, and input shaft 6 and planet carrier chassis 91 clearance sets up, and input shaft 6 can not cause the interference to input shaft 6's rotation at the planet carrier of rotation in-process to guarantee that input shaft 6 inputs the power that the motor produced smoothly.

The planetary gear set comprises a plurality of planetary gears 8, a plurality of mounting positions 911 of the planetary gears 8 are arranged on the planet carrier chassis 91, and the plurality of planetary gears 8 are rotatably arranged on the mounting positions 911 of the planetary gears 8 and are simultaneously meshed with the sun gear 7 and the internal gear 11 of the wave generator 1. The plurality of planet gears 8 are arranged in one-to-one correspondence with the plurality of mounting positions 911 of the planet gears 8, preferably, the mounting positions 911 of the planet gears 8 are connecting shafts formed by extending the planet carrier chassis 91 towards the inside of the wave generator 1, and the planet gears 8 are rotatably connected with the connecting shafts. Preferably, the plurality of planet gears 8 are evenly distributed along the circumference of the sun gear 7. It is further preferred that there are two planet gears 8, and the two planet gears 8 are symmetrically distributed along the radial direction of the sun gear 7.

Further optionally, the planet carrier base plate 91 is shaped like a disk, and the size of the planet carrier base plate 91 is larger than that of the wave generator 1; the planet carrier also comprises a planet carrier side wall which is arranged around the planet carrier chassis 91, and the wave generator 1 is arranged in a cavity formed by the planet carrier chassis 91 and the planet carrier side wall. A certain gap is formed between the side wall of the planet carrier and the outer side wall of the wave generator 1, the flexible gear 2 is positioned in the gap and sleeved on the outer side wall of the wave generator 1 to be fixedly matched with the outer side wall of the wave generator 1, the planet carrier is fixed on the rigid gear 3, and the rigid gear 3 is sleeved on the outer side of the flexible gear 2 to be matched with the flexible gear 2.

Further alternatively, as shown in fig. 3 and 4, the end surface of the side wall of the planet carrier comprises an outer end surface 921 and an inner end surface 922 from outside to inside, the inner end surface 922 is sunken to form a certain height difference with the outer end surface 921, and the rigid wheel 3 is fixed on the inner end surface 922. A plurality of screw holes 9221 are formed in the inner end face, matching holes matched with the screw holes 9221 are formed in the corresponding positions of the rigid wheel 3, and the rigid wheel 3 is fixed on the inner end face 922 through screws sequentially penetrating through the matching holes and the screw holes. Preferably, the height difference between the outer end surface 921 and the inner end surface 922 is less than or equal to the thickness of the rigid wheel (3); so that the rigid wheel 3 is well matched with the planet carrier when being fixed on the planet carrier; and/or the width of the inner end surface 922 is smaller than or equal to the width of the rigid wheel 3, so that the stability of the planet carrier fixed on the rigid wheel 3 is ensured.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A multi-stage geared harmonic reducer, comprising:

the primary planetary gear transmission mechanism comprises a wave generator (1) with an internal gear (11) and an input shaft (6) arranged on the wave generator (1) in a penetrating mode, wherein the input end of the input shaft (6) is connected with a driving motor, and the output end of the input shaft is provided with a sun gear (7); a planetary gear set is arranged between the sun gear (7) and an internal gear (11) of the wave generator (1), and the planetary gear set is simultaneously meshed with the sun gear (7) and the internal gear (11) of the wave generator (1);

the second-order harmonic gear transmission mechanism comprises a flexible gear (2), and the flexible gear (2) is sleeved on the outer side wall of the wave generator (1);

in the operation process of the harmonic reducer, the primary planetary gear transmission mechanism transmits power input by the input shaft (6) to the wave generator (1) through the sun gear (7) and the planetary gear set, then the wave generator (1) transmits the power to the secondary harmonic gear transmission mechanism, and the power is output by the flexible gear (2).

2. Harmonic reducer according to claim 1, characterized in that said sun gear (7) is in fixed engagement with said input shaft (6), said rotation of said input shaft (6) bringing about the rotation of said sun gear (7).

3. Harmonic reducer according to claim 1, characterized in that the wave generator (1) is of elliptical ring structure, the internal gears (11) being circumferentially distributed along the inner wall of the elliptical ring, the planetary gear set being located between the inner wall of the elliptical ring structure and the sun gear (7) and meshing simultaneously with the sun gear (7) and the internal gears (11).

4. A harmonic reducer according to claim 3, wherein the sun gear (7) is arranged centrally of the elliptical ring structure by means of the input shaft (6), the planetary gear set comprising a plurality of planet gears (8), the plurality of planet gears (8) being evenly distributed along the circumference of the sun gear (7).

5. Harmonic reducer according to claim 4, characterized in that said planet gears (8) are two, said two planet gears (8) being symmetrically distributed along the radial direction of said sun gear (7).

6. The harmonic reducer according to any one of claims 1-5, further comprising a rigid wheel (3) and a rigid bearing, wherein the rigid wheel (3) is sleeved on the outer side wall of the flexible wheel (2) and is in tooth fit with the flexible wheel (2); the rigid bearing comprises a rigid bearing inner ring (4) and a rigid bearing outer ring (5), the rigid wheel (3) is connected with the rigid bearing inner ring (4) to serve as a fixed part of the harmonic reducer, and the flexible wheel (2) is connected with the rigid bearing outer ring (5) to serve as an output part of the harmonic reducer.

7. A harmonic reducer according to claim 6 in which the primary planetary gear further comprises a planet carrier comprising a planet carrier chassis (91), the output of the input shaft (6) passes through the planet carrier chassis (91) and then extends into the wave generator (1), and the input shaft (6) and the planet carrier chassis (91) are arranged with clearance;

planetary gear set includes a plurality of planetary gear (8), be equipped with a plurality of planetary gear (8) installation position (911) on planet carrier chassis (91), a plurality of planetary gear (8) rotatable setting are in on a plurality of planetary gear (8) installation position (911), and simultaneously with sun gear (7) with internal gear (11) meshing of wave generator (1).

8. Harmonic reducer according to claim 7, characterized in that said planetary gear (8) mounting location (911) is a connecting shaft formed by said planet carrier chassis (91) extending towards the inside of said wave generator (1), said planetary gear (8) being rotatably connected with said connecting shaft.

9. Harmonic reducer according to claim 8, characterized in that said planet carrier base disc (91) is shaped like a disc and in that the dimensions of said planet carrier base disc (91) are greater than those of said wave generator (1);

the planet carrier also comprises a planet carrier side wall arranged around the planet carrier chassis (91), and the wave generator (1) is arranged in a cavity formed by the planet carrier chassis (91) and the planet carrier side wall; the planet carrier lateral wall with form certain clearance between the lateral wall of wave generator (1), flexbile gear (2) are located establish in the clearance and the cover establish on the lateral wall of wave generator (1) with the lateral wall fixed coordination of wave generator (1), the planet carrier lateral wall is fixed on rigid gear (3), and the outside and flexbile gear (2) tooth cooperation at flexbile gear (2) are established to rigid gear (3) cover.

10. The harmonic reducer according to claim 9, wherein the end surfaces of the side walls of the planet carrier comprise an outer end surface (921) and an inner end surface (922) from outside to inside, the inner end surface (922) is sunken and arranged to form a certain height difference with the outer end surface (921), and the rigid wheel (3) is fixed on the inner end surface (922).

11. A harmonic reducer according to claim 10 in which the difference in height of the outer end face (921) and the inner end face (922) is less than or equal to the thickness of the rigid wheel (3);

and/or the width of the inner end surface (922) is smaller than or equal to the width of the rigid wheel (3).

12. A robot having a harmonic reducer as claimed in any one of claims 1 to 11.