CN219013276U - Planetary reducer with small tooth difference and servo system with same - Google Patents

Abstract

The utility model provides a planetary reducer with small tooth difference and a servo system with the same, relates to the technical field of transmission equipment, and mainly aims to solve the technical problems of large occupied space and low efficiency of the reducer in the prior art. The planetary reducer with small tooth difference comprises an input shaft and a fixed wheel set, wherein the fixed wheel set comprises a fixed planetary gear, and the fixed planetary gear is connected with the input shaft and can rotate under the drive of the input shaft; the sun gear is a coaxial differential gear, and at least two layers of gears with different tooth numbers are arranged in the axial direction of the sun gear; the sun gear is meshed with the fixed planetary gear and can rotate under the drive of the fixed planetary gear; the output wheel set comprises an output planetary gear which is meshed with the sun gear and can rotate under the drive of the sun gear; the output planet wheel and the fixed planet wheel are respectively connected with the gears at different layers in the axis direction of the sun gear.

Description

Planetary reducer with small tooth difference and servo system with same

Technical Field

The utility model relates to the technical field of transmission equipment, in particular to a planetary reducer with small tooth difference and a servo system with the planetary reducer.

Background

At present, a high reduction ratio servo system is mostly adopted for force control of a robot joint, especially in an environment where high load is required by industry. Because the traditional high-reduction ratio gear has large friction, unacceptable errors are brought to force control, an additional force sensor is required to detect the force interacted with the environment, and then servo rotation is controlled through a position closed-loop algorithm so that the interaction force reaches an expected value. The sensor has a complex structure and low force response speed, but has higher torque/weight ratio, and is suitable for high-load occasions; but at the same time, the speed reducer has the defects of large occupied space, low transmission efficiency and easy occurrence of self-locking. In order to solve the above-mentioned drawbacks, a low reduction ratio servo system has been developed. Because the reduction ratio is low, the friction force of the gears is negligible, so that the servo system can directly control the output force of the robot joint by controlling the current of the motor winding. The scheme has the advantages of simple structure, high response speed and low cost, but has lower torque/weight, and is not suitable for high-load occasions.

In order to solve the defects, the problems of self-locking and difficult flexible torque control of the speed reduction equipment are solved while the defects of large occupied space and low transmission efficiency of the speed reduction equipment are overcome, and a novel planetary speed reducer with small tooth difference and a servo system with the speed reducer are required to be developed.

Disclosure of Invention

The utility model aims to provide a planetary reducer with small tooth difference and a servo system with the same, so as to solve the technical problems of large occupied space and low efficiency of the reducer in the prior art. The preferred technical solutions of the technical solutions provided by the present utility model can produce a plurality of technical effects described below.

In order to achieve the above purpose, the present utility model provides the following technical solutions:

the utility model provides a planetary reducer with small tooth difference, which comprises:

an input shaft;

the fixed wheel set comprises fixed planetary wheels, and the fixed planetary wheels are connected with the input shaft and can rotate under the drive of the input shaft;

the sun gear is a coaxial differential gear, and at least two layers of gears with different tooth numbers are arranged in the axial direction of the sun gear; the sun gear is meshed with the fixed planetary gear and can rotate under the drive of the fixed planetary gear;

the output wheel set comprises an output planetary gear which is meshed with the sun gear and can rotate under the drive of the sun gear;

the output planet wheel and the fixed planet wheel are respectively connected with the gears at different layers in the axis direction of the sun gear.

On the basis of the technical scheme, the utility model can be improved as follows.

As a further development of the utility model, the number of the fixed planetary gears is at least two and all the fixed planetary gears are connected with the sun gear;

and/or the number of the output planetary gears is at least two, and all the output planetary gears are connected with the sun gear.

As a further improvement of the utility model, the fixed wheel set further comprises a fixed planet carrier, and the fixed planet wheels are fixedly arranged on the fixed planet carrier;

the output wheel set further comprises an output planet carrier, and the output planet carrier is connected with the output planet wheel and can rotate under the drive of the output planet wheel.

As a further improvement of the utility model, the output planet carrier extends towards the direction of the sun gear and forms a limit post, and the sun gear is sleeved on the limit post.

As a further improvement of the utility model, the input shaft is of a hollow annular structure with teeth arranged on the inner wall, and the fixed planet wheel is meshed with the inner wall of the input shaft.

The utility model also provides a servo system which comprises a motor and the small-tooth-difference planetary reducer, wherein the motor is positioned on the outer side of the small-tooth-difference planetary reducer and can drive the input shaft to rotate.

As a further improvement of the utility model, the motor is arranged in parallel with the small-tooth-difference planetary reducer.

As a further improvement of the utility model, the motor is connected with the input shaft through a synchronous belt and drives the input shaft to rotate;

alternatively, the motor is coupled to the input shaft via a meshing drive.

As a further improvement of the utility model, the planetary reducer further comprises a shell, wherein the planetary reducer with small tooth difference and the motor are both positioned in the shell;

the shell comprises an upper cover and a lower cover, the fixed wheel set is fixedly arranged on the upper cover, an output hole is formed in the lower cover, and part of the output wheel set is connected with the lower cover through a bearing and is exposed through the output hole.

As a further improvement of the utility model, a servo control board is arranged outside the motor;

and/or an output angle sensor is arranged on the small-tooth-difference planetary reducer, and the output angle sensor is used for detecting the rotation angle of the output wheel set.

Compared with the prior art, the technical scheme provided by the preferred embodiment of the utility model has the following beneficial effects:

according to the scheme, the speed and the torque between the input shaft and the output wheel set can be conveniently adjusted through the sun gear formed by the coaxial differential gear, and the input shaft driven at high speed can realize low-speed and high-torque output; in addition, due to the special structure of the sun gear, the speed reducer can effectively shorten the space occupation of the speed reducer in the axial direction, overcome the friction force problem and avoid the self-locking phenomenon of the speed reducer; the servo system using the speed reducer can further reduce the volume of the equipment in the axis direction and the occupied space through the structural design that the motor and the speed reducer are arranged side by side, and meanwhile, the control of the output force can be conveniently realized by detecting the rotation angle of the output wheel set.

Drawings

In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of the overall structure of a small tooth difference planetary reducer of the present utility model;

FIG. 2 is a schematic cross-sectional view of a planetary reducer with small tooth difference according to the present utility model;

FIG. 3 is an exploded view of the small tooth difference planetary reducer of the present utility model;

FIG. 4 is a schematic diagram of the structure of the output planet carrier in the small tooth difference planetary reducer of the present utility model;

FIG. 5 is a schematic diagram of the overall structure of the servo system of the present utility model;

FIG. 6 is a schematic cross-sectional view of a servo system according to the present utility model;

FIG. 7 is an exploded view of one embodiment of a servo system of the present utility model;

FIG. 8 is a schematic structural view of the input shaft of FIG. 7;

FIG. 9 is an exploded view of another embodiment of a servo system of the present utility model;

fig. 10 is a schematic structural view of the input shaft in fig. 9.

In the figure: 1. an input shaft; 2. a fixed wheel set; 21. fixing a planet wheel; 22. fixing the planet carrier; 3. a sun gear; 31. a gear; 4. an output wheel set; 41. outputting a planet wheel; 42. an output planet carrier; 43. a limit column; 5. a motor; 6. a synchronous belt; 7. a housing; 71. an upper cover; 72. a lower cover; 721. an output aperture; 8. a servo control board; 9. and outputting an angle sensor.

Detailed Description

In order to make the objects, technical solutions and advantages of the present utility model more apparent, the technical solutions of the present utility model will be described in detail below. It will be apparent that the described embodiments are only some, but not all, embodiments of the utility model. All other embodiments, based on the examples herein, which are within the scope of the utility model as defined by the claims, will be within the scope of the utility model as defined by the claims.

In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model. Furthermore, the terms "first," "second," "third," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present utility model, it should also be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in the present utility model can be understood as appropriate by those of ordinary skill in the art.

The technical scheme of the utility model is specifically described below with reference to the accompanying drawings.

The utility model provides a planetary reducer with small tooth difference, which comprises an input shaft 1, a fixed wheel set 2, a sun wheel 3 and an output wheel set 4, wherein the input shaft 1 can be driven and rotated, the fixed wheel set 2 comprises a fixed planetary wheel 21 connected with the input shaft 1, and when the input shaft 1 rotates, the fixed planetary wheel 21 can be driven to rotate by the fixed planetary wheel. The sun gear 3 is not a coaxial differential gear (i.e. a tower planet gear), at least two layers of gear 31 structures with different tooth numbers are arranged in the axial direction of the sun gear, one layer of the gears 31 can be meshed with the fixed planet gear 21 and can rotate under the drive of the fixed planet gear 21, and the gears 31 positioned on the other layer in the axial direction of the sun gear 3 can be connected with the output wheel set 4.

Specifically, the output wheel set 4 includes an output planetary gear 41, where the output planetary gear 41 is meshed with the sun gear 3 and can rotate under the drive of the sun gear 3.

In the present embodiment, the number of the fixed planetary gears 21 is at least two, and all the fixed planetary gears 21 are connected with the sun gear 3; the number of output planet wheels 41 is at least two and all output planet wheels 41 are connected to the sun wheel 3. In addition, the fixed wheel set 2 further comprises a fixed planet carrier 22, and the fixed planet wheels 21 are fixedly arranged on the fixed planet carrier 22; the output wheel set 4 further comprises an output planet carrier 42, and the output planet carrier 42 is connected with the output planet wheel 41 and can rotate under the drive of the output planet wheel 41.

As shown in fig. 1-2, the fixed planet carrier 22 in the fixed wheel set 2 is always fixed, and when the input shaft 1 rotates, the fixed planet wheel 21 can rotate along with the rotation of the output shaft and drive the sun wheel 3 meshed with the fixed planet wheel to synchronously rotate. Since the number of teeth on the different gears 31 of the sun gear 3 is different, the rotational speeds of the fixed planetary gear 21 and the output planetary gear 41 respectively engaged with the different gears 31 on the sun gear 3 are different. It should be noted that, in addition to the rotation, the output planetary gear 41 also revolves around the sun gear 3, that is, the output planetary gear 41 drives the output planetary carrier 42 to rotate.

That is, the output rotational speed of the small-tooth-difference planetary reducer is the rotation speed of the output carrier 42.

Since the number of teeth of the different gears 31 in the axial direction of the sun gear 3 is different, the rotation speed of the fixed planetary gear 21 is different from the rotation speed of the output planetary gear 41, and a speed difference exists between the two.

Specifically, the rotational speed of the output carrier 42 depends on the speed difference between the sun gear 3 and the input shaft 1, which is dependent on the difference in the number of teeth of the gear 31 at different positions on the axis of the sun gear 3: when the difference in the number of teeth is small, the above-mentioned difference in speed is small, and the rotational speeds of the output carrier 42 meet, at which time the reduction ratio of the reduction gear is high.

In the present embodiment, the number of the fixed planetary gears 21 and the output planetary gears 41 is three and are uniformly distributed around the sun gear 3.

The sun gear 3 has gears 31 with different diameters on its axis, and the gears 31 are engaged with the fixed planetary gear 21 and the output planetary gear 41.

In order to fix the sun gear 3 well and enable it to rotate stably, as an alternative embodiment, the output planet carrier 42 extends towards the direction of the sun gear 3 and forms a limit post 43, and as shown in fig. 4, the sun gear 3 is sleeved on the limit post 43.

In order to further reduce the thickness of the reducer in the axial direction and to reduce the space occupation in the axial direction, as an alternative embodiment, the input shaft 1 is provided with a hollow annular structure with teeth on the inner wall, and the fixed planetary gears 21 are meshed with the inner wall of the input shaft 1.

At this time, the input shaft 1 is a gear ring structure arranged at the outermost side of the speed reducer and can be connected with corresponding driving equipment positioned outside the speed reducer, so that the space occupation of the speed reducer in the axial direction is effectively reduced, and the whole equipment is thinner.

It will be appreciated that the overall structure of the reducer is as shown in figures 1 and 3. Under the action of the fixed wheel set 2, the sun wheel 3 and the output wheel set 4, the speed reducer can perform speed reduction processing on the rotation speed input at the input shaft 1, and the corresponding rotation speed and torque are output by the output planet carrier 42. Compared with the traditional speed reducer, the speed reducer has thinner thickness in the axial direction, and has higher reduction ratio, so that the problems of large occupied space, low transmission efficiency and self-locking caused by multi-stage speed reduction of the traditional speed reducer can be effectively solved.

The utility model also provides a servo system which comprises a motor 5 and the small-tooth-difference planetary reducer, wherein the motor 5 is positioned on the outer side of the small-tooth-difference planetary reducer and can drive the input shaft 1 to rotate.

In the present embodiment, as shown in fig. 5 to 6, the motor 5 is arranged in parallel with the small-tooth-difference planetary reducer at this time.

By means of the structural design, the thickness of the servo system can be effectively reduced.

In practical use, the motor 5 and the planetary reducer with small teeth difference can be connected in various different manners, as shown in fig. 7, at this time, the motor 5 and the planetary reducer with small teeth difference are connected through a synchronous belt 6, the synchronous belt 6 is simultaneously connected with the motor 5 and the input shaft 1 of the planetary reducer with small teeth difference, and when the motor 5 is started, the synchronous belt 6 can rotate under the driving of the motor 5 and drive the input shaft 1 to rotate, at this time, the structure of the input shaft 1 is shown in fig. 8. Alternatively, as shown in fig. 9, in this case, the motor 5 and the small-tooth-difference planetary reducer are engaged with each other, teeth are formed on the outer peripheral side of the motor 5, and teeth engaged with the small-tooth-difference planetary reducer are also formed on the outer peripheral side of the input shaft 1, and as shown in fig. 10, the motor 5 and the input shaft 1 are engaged with each other. When the motor 5 is started, the input shaft 1 can be rotated synchronously with the rotation of the motor 5.

In addition, the servo system also comprises a shell 7, and the small-tooth-difference planetary reducer and the motor 5 are both positioned in the shell 7; the housing 7 includes an upper cover 71 and a lower cover 72, the fixed wheel set 2 is fixedly arranged on the upper cover 71, an output hole 721 is arranged on the lower cover 72, and a part of the output wheel set 4 is connected with the lower cover 72 through a bearing and is exposed through the output hole 721.

In the present embodiment, the output carrier 42 is coupled to the lower cover 72 by a bearing and is exposed through the output hole 721.

As an alternative embodiment, a servo control board 8 is arranged outside the motor 5; and/or, an output angle sensor 9 is arranged on the planetary reducer with small tooth difference, and the output angle sensor 9 is used for detecting the rotation angle of the output wheel set 4.

The arrangement position of the output angle sensor 9 is shown in fig. 6, and the output angle sensor 9 can directly detect the rotation of the output carrier 42.

Because the planetary speed reducer with small tooth difference is only one stage, the friction loss is small, and therefore, the torque control can be directly realized through the current control. In this embodiment, the servo control board 8 (on which a current sensor is disposed) installed inside the housing and located outside the motor 5 can realize directional control of the magnetic field, so as to achieve the purpose of controlling the torque and current of the motor 5, and further control the current of the output end of the speed reducer.

It should be noted that the output angle sensor 9 may be any motion information sensor such as an optical encoder, a magnetic encoder, an inertial sensor, an eddy current sensor, or the like.

The structure and mounting of the above sensors are already known in the art and will not be described in detail herein.

It can be understood that the servo system provided by the scheme has higher precision in a torque control scene, is more flexible in use, and has the advantages of compact structure and small volume.

The foregoing is merely illustrative of the present utility model, and the present utility model is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to the protection scope of the claims.

Claims (10)

1. A planetary reducer with small tooth difference, characterized by comprising:

an input shaft;

the fixed wheel set comprises fixed planetary wheels, and the fixed planetary wheels are connected with the input shaft and can rotate under the drive of the input shaft;

the sun gear is a coaxial differential gear, and at least two layers of gears with different tooth numbers are arranged in the axial direction of the sun gear; the sun gear is meshed with the fixed planetary gear and can rotate under the drive of the fixed planetary gear;

the output wheel set comprises an output planetary gear which is meshed with the sun gear and can rotate under the drive of the sun gear;

the output planet wheel and the fixed planet wheel are respectively connected with the gears at different layers in the axis direction of the sun gear.

2. The small tooth difference planetary reducer according to claim 1, characterized in that the number of the fixed planetary gears is at least two and all the fixed planetary gears are connected with the sun gear;

and/or the number of the output planetary gears is at least two, and all the output planetary gears are connected with the sun gear.

3. The small tooth difference planetary reducer of claim 1, wherein the fixed wheelset further comprises a fixed planet carrier, the fixed planet wheels being fixedly disposed on the fixed planet carrier;

the output wheel set further comprises an output planet carrier, and the output planet carrier is connected with the output planet wheel and can rotate under the drive of the output planet wheel.

4. A small tooth difference planetary reducer according to claim 3, wherein the output planet carrier extends towards the direction of the sun gear and forms a limit post, and the sun gear is sleeved on the limit post.

5. The small teeth difference planetary reducer according to any of claims 1-4, characterized in that said input shaft is a hollow ring structure with teeth provided on the inner wall, said fixed planetary wheels being meshed with the inner wall of said input shaft.

6. A servo system comprising a motor and the small tooth difference planetary reducer of any one of claims 1-5, wherein the motor is located outside the small tooth difference planetary reducer and is capable of driving the input shaft to rotate.

7. The servo system of claim 6 wherein the motor is juxtaposed with the low differential planetary reducer.

8. The servo system of claim 7 wherein the motor is coupled to the input shaft by a timing belt and drives the input shaft to rotate;

alternatively, the motor is coupled to the input shaft via a meshing drive.

9. The servo system of claim 6 further comprising a housing, wherein the low differential planetary reducer and the motor are both located within the housing;

the shell comprises an upper cover and a lower cover, the fixed wheel set is fixedly arranged on the upper cover, an output hole is formed in the lower cover, and part of the output wheel set is connected with the lower cover through a bearing and is exposed through the output hole.

10. The servo system of claim 6 wherein a servo control board is provided outside the motor;

and/or an output angle sensor is arranged on the small-tooth-difference planetary reducer, and the output angle sensor is used for detecting the rotation angle of the output wheel set.

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