Planetary reducer and integrated joint
Technical Field
The invention relates to the technical field of humanoid robot design, in particular to a planetary reducer and an integrated joint.
Background
The integrated driving joint of the humanoid robot needs to have good reverse driving capability, so that the robot has certain flexibility when suffering collision or falling, and the robot can safely run.
However, the current harmonic reducer has extremely low reverse transmission efficiency, and the driving joint using the harmonic reducer does not have the capability of reverse driving, so that the robot is extremely easy to damage when being collided or fallen, and is not suitable for the driving unit of the humanoid robot.
The planetary reducer can realize larger bearing capacity and has high-efficiency forward and reverse transmission capacity, so that the planetary reducer is suitable for a transmission system of a humanoid robot driving unit; however, since the existing planetary reducer has a backlash in the gear transmission, the existing planetary reducer has a transmission backlash, so that the robot driving joint is easy to cause impact when the transmission is reversely changed, and the transmission accuracy is reduced.
Therefore, a planetary reducer capable of effectively avoiding transmission gaps is needed to realize forward and reverse motion output without transmission gaps, so that the transmission precision and transmission efficiency of the reducer are improved, and the robot is ensured to run stably and reliably.
Disclosure of Invention
In view of the above problems, the present invention is to provide a planetary reducer and an integrated joint, so as to solve the problem that a transmission gap exists in the planetary reducer in the integrated driving joint of the existing humanoid robot.
The planetary reducer comprises a first sun gear, a second sun gear, a first annular gear, a second annular gear and an output shaft which are coaxially arranged; wherein,,
the first sun gear and the second sun gear are connected in parallel, the first annular gear is arranged on the peripheries of the first sun gear and the second sun gear, a first planet gear is meshed and connected between the first sun gear and the first annular gear, and a second planet gear is meshed between the second sun gear and the first annular gear; and, in addition, the processing unit,
one side of the first planet wheel is provided with a third planet wheel and a fourth planet wheel, the third planet wheel is fixedly connected with the first planet wheel in a synchronous mode, the fourth planet wheel is fixedly connected with the second planet wheel in a synchronous mode, the third planet wheel and the fourth planet wheel are meshed with the second annular gear, and the output shaft is fixedly connected with the second annular gear in a synchronous mode.
In addition, the first sun gear and the second sun gear are preferably rotationally connected by a first bearing to form a parallel structure.
Furthermore, it is preferable that the first planetary gear and the third planetary gear are coaxial and fixedly connected by a flat key; the second planet wheel and the fourth planet wheel are of an integrated duplex gear structure.
In addition, preferably, the integrated duplex gear structure is rotatably connected with the shaft of the first planet through a second bearing, so as to form a parallel structure.
In addition, the preferred scheme is that the motor further comprises a shell, the first annular gear is fixedly connected with the shell, and the second annular gear is rotatably connected with the shell through a third bearing.
In addition, the planetary gear system preferably further comprises a planetary gear carrier, and the first planetary gear, the second planetary gear, the third planetary gear and the fourth planetary gear are all mounted on the planetary gear carrier.
On the other hand, the invention also provides an integrated joint, which comprises a first motor, a second motor and the planetary reducer; wherein,,
the first motor comprises a first rotor and a first stator, the second motor comprises a second rotor and a second stator, the first stator and the second stator are both fixed on a shell of the planetary reducer, the first rotor is fixedly connected with a shaft of the first sun gear, and the second rotor is fixedly connected with a shaft of the second sun gear.
In addition, the integrated joint preferably further comprises a first encoder and a second encoder, wherein the first encoder is electrically connected with the first motor, and the second encoder is electrically connected with the second motor.
In addition, preferably, the first motor drives the first sun gear to rotate, and the second motor drives the second sun gear to rotate; and, in addition, the processing unit,
the phase difference between the first motor and the second motor corresponds to the transmission clearance value of the planetary reducer.
In addition, preferably, during the operation of the planetary reducer,
the first sun gear is tightly attached to the tooth surface of one side of the meshing gear pair of the first planet gear, and the first planet gear is tightly attached to the tooth surface of the other side of the meshing gear pair of the first inner gear ring;
the second sun gear is tightly attached to the tooth surface of one side of the meshing gear pair of the second planet gear, and the second planet gear is tightly attached to the tooth surface of the other side of the meshing gear pair of the first inner gear ring;
the third planet wheel is tightly attached to the tooth surface of one side of the meshing gear pair of the second inner gear ring, and the fourth planet wheel is tightly attached to the tooth surface of the other side of the meshing gear pair of the second inner gear ring.
Compared with the prior art, the planetary reducer provided by the invention has the following beneficial effects:
in the planetary reducer in the integrated joint, when in forward transmission, a motor (comprising a first motor and a second motor) moves, and is input by a sun gear (comprising a first sun gear and a second sun gear), and the second inner gear is output; and during reverse transmission, the motor motion is input by the second annular gear and output by the sun gear. The two parallel sun gears are respectively driven by two motors, and are respectively meshed with two parallel planetary gears, and the motion is transmitted to the parallel planetary gear at the other side through the same fixed annular gear, and the parallel planetary gear is meshed with the same output annular gear, so that the final motion is output. In reverse drive, the situation is the opposite. The two motors keep a certain phase difference during operation, so that the speed reduction transmission system can realize the motion output without transmission gaps in the forward direction and the reverse direction, the transmission precision of the speed reducer is improved, and the vibration and the impact are reduced. The excellent reverse driving capability of the planetary reducer provided by the invention can enable the robot to have good flexibility or good interaction capability with the external environment, and can avoid damage when the robot is impacted or falls down, or can ensure intrinsically safe man-machine interaction when cooperating with a person; the speed reducer can realize high-efficiency forward and reverse transmission capacity through the arrangement of parameters such as the number of teeth, the displacement coefficient and the like, so that the integrated joint has excellent bidirectional driving capacity.
To the accomplishment of the foregoing and related ends, one or more aspects of the invention comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative aspects of the invention. These aspects are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Furthermore, the invention is intended to include all such aspects and their equivalents.
Drawings
Other objects and results of the present invention will become more apparent and readily appreciated by reference to the following description and claims in conjunction with the accompanying drawings and a more complete understanding of the invention. In the drawings:
FIG. 1 is a schematic diagram of an integrated joint provided by an embodiment of the present invention;
FIG. 2 is a schematic cross-sectional view of an integrated joint according to an embodiment of the present invention;
FIG. 3 is a side cross-sectional view of an integrated joint in the A-A or B-B position according to an embodiment of the present invention;
FIG. 4 is a side cross-sectional view of an integrated joint in the C-C or D-D position according to an embodiment of the present invention;
FIG. 5 is a gear mesh state diagram of the planetary reducer at the A-A and B-B positions provided by an embodiment of the present invention;
FIG. 6 is a gear mesh state diagram of the planetary reducer in the C-C and D-D positions provided by an embodiment of the present invention;
reference numerals: the planetary gear system comprises a first sun gear S1, a second sun gear S2, a first annular gear R1, a second annular gear R2, an output shaft 100, a first planetary gear P11, a second planetary gear P21, a third planetary gear P12, a fourth planetary gear P22, a first stator M11, a first rotor M12, a second stator M21, a second rotor M22, a first encoder 200, a second encoder 300, a bearing 400, a planet carrier 500, a flat key 600 and a machine shell 700.
The same reference numerals will be used throughout the drawings to refer to similar or corresponding features or functions.
Detailed Description
In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more embodiments. It may be evident, however, that such embodiment(s) may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to facilitate describing one or more embodiments.
Fig. 1 illustrates the principle of an integrated joint provided by an embodiment of the present invention, fig. 2 illustrates a front view cross-sectional structure of an integrated joint provided by an embodiment of the present invention, fig. 3 illustrates a side view cross-sectional structure of an integrated joint provided by an embodiment of the present invention at A-A or B-B position, and fig. 4 illustrates a side view cross-sectional structure diagram of an integrated joint provided by an embodiment of the present invention at a C-C or D-D position.
As can be seen from fig. 1 to 4, the planetary reducer in the integrated joint provided by the present invention includes a first sun gear S1, a second sun gear S2, a first ring gear R1, a second ring gear R2, and an output shaft 100 coaxially disposed; the first sun gear S1 and the second sun gear S2 are arranged side by side, the first sun gear S1 and the second sun gear S2 are connected in parallel to form a parallel structure, the first ring gear R1 is arranged at the periphery of the first sun gear S1 and the second sun gear S2 (i.e., the first ring gear R1 is arranged around the first sun gear S1 and the second sun gear S2), a first planet gear P11 is meshed and connected between the first sun gear S1 and the first ring gear (i.e., one side of the first planet gear P11 is meshed with the first sun gear S1, the other side is meshed with the first ring gear), and a second planet gear P21 is meshed between the second sun gear S2 and the first ring gear (i.e., one side of the second planet gear P21 is meshed with the second sun gear S2, and the other side is meshed with the second ring gear); a third planetary gear P12 and a fourth planetary gear P22 are disposed on one side of the first planetary gear P11 (or the second planetary gear P21), the third planetary gear P12 is fixedly connected with the first planetary gear P11 in synchronization (coaxial and synchronously rotating, and the following is the same), the fourth planetary gear P22 is fixedly connected with the second planetary gear P21 in synchronization, the second ring gear R2 is disposed on the peripheries of the third planetary gear P12 and the fourth planetary gear P22, the third planetary gear P12 and the fourth planetary gear P22 are engaged with the second ring gear R2, and the output shaft 100 is fixedly connected with the second ring gear R2 in synchronization.
The first sun gear S1, the second sun gear S2, the first ring gear R1, the second ring gear R2, and the output shaft 100 are coaxially disposed, which means that the central axes of the components are on the same line, but the rotational relationships between the components are not necessarily synchronous.
Specifically, in order to achieve parallel connection of the first sun gear S1 and the second sun gear S2, the first sun gear S1 and the second sun gear S2 may form a relatively rotatable connection through the first bearing, so as to form a parallel structure, and achieve parallel connection of the two. Furthermore, to achieve a synchronous fixation of the first planet wheel P11 and the third planet wheel P12, the first planet wheel P11 and the third planet wheel P12 may be coaxially arranged and fixedly connected by means of a flat key 600. In addition, because the distance between the second planet wheel P21 and the fourth planet wheel P22 is relatively close and the structures are the same, in order to realize synchronous fixation of the fourth planet wheel P22 and the second planet wheel P21, the second planet wheel P21 and the fourth planet wheel P22 can be directly arranged into an integrated structure, and an integrated duplex gear structure is formed between the two, so that synchronous fixation between the two is realized. In addition, in order to achieve parallel connection between the second planetary gear P21 (or the fourth planetary gear P22) and the first planetary gear P11 (or the third planetary gear P12), an integrated duplex gear structure composed of the second planetary gear P21 and the fourth planetary gear P22 may form a relatively rotatable connection with the shaft of the first planetary gear P11 through the second bearing, thereby forming a parallel structure.
More specifically, in order to realize stable support between each component in the planetary reducer provided by the invention, the planetary reducer further comprises a casing 700 and a planet carrier 500, wherein the first annular gear R1 can be directly and fixedly connected with the casing 700, the output shaft 100 can be arranged into an integrated structure with the second annular gear R2, and the second annular gear R2 can form a relatively rotatable connection with the casing 700 through a third bearing. The first planet wheel P11, the second planet wheel P21, the third planet wheel P12 and the fourth planet wheel P22 are all installed on the planet carrier 500, the planet carrier 500 and the shaft of the second sun wheel S2 form a relatively rotatable connection through a fourth bearing, one end of the shaft of the second sun wheel S2 and the output shaft 100 form a relatively rotatable connection through a fifth bearing, and the other end of the shaft of the second sun wheel S2 is installed in a preset hole of the machine shell 700 through a bearing, so that two-end support is achieved. The shaft of the first planet gear P11 is mounted on the planet carrier 500 through a sixth bearing, and is uniformly distributed along the circumference through the planet carrier 500, and is uniformly loaded.
It should be noted that, in the connection relationship between the components in the planetary reducer provided by the present invention, the bearing 400 (including the first bearing to the sixth bearing) is used to realize the connection between the two components capable of rotating relatively, and the specific structure of the inner end of the bearing and the working principle thereof are common knowledge in the art and are described in many existing documents, and are not repeated herein.
In order to explain the working principle of the planetary reducer in the integrated driving joint of the humanoid robot in detail, the invention also provides an integrated joint which comprises the planetary reducer, a first motor and a second motor; the first motor comprises a first rotor M12 and a first stator M11, and the second motor comprises a second rotor M22 and a second stator M21; the first rotor M12, the first stator M11, the second rotor M22, and the second stator M21 are coaxially configured, and the planetary gear reducer, the first stator M11, the second stator M21, the first rotor M12, and the second rotor M22 are integrated in the casing 700 in a serial manner; specifically, the first stator M11 and the second stator M21 are both mounted on the casing 700 and form a fixed connection, the first rotor M12 is mounted on the shaft of the first sun gear S1 in the planetary reducer and is fixedly connected, and the second rotor M22 is mounted on the shaft of the second sun gear S2 in the planetary reducer and is fixedly connected.
In addition, in order to realize driving control of the first motor and the second motor, the integrated joint provided by the invention may further include a first encoder 200 and a second encoder 300, wherein the first encoder 200 is electrically connected with the first motor, the second encoder 300 is electrically connected with the second motor, the first encoder 200 is used for driving control of the first motor, and the second encoder 300 is used for driving control of the second motor.
It should be noted that, in the actual use process, the first motor drives the first sun gear S1 to rotate, and the second motor drives the second sun gear S2 to rotate; in addition, in order to eliminate the transmission clearance in the planetary reducer, the rotation phase difference between the first motor and the second motor needs to correspond to the transmission clearance value of the planetary reducer.
Specifically, as shown in fig. 5 and 6, during actual use, the two motors respectively drive the first sun gear S1 and the second sun gear S2 to rotate in different directions by an angle value to form an angle difference, and the angle difference (corresponding to the phase difference between the first motor and the second motor) needs to be equal to a micro angle of a tooth side clearance value (corresponding to the transmission clearance value of the planetary reducer), the tooth surfaces of one side of the meshing gear pair of the first sun gear S1 and the first planet gear P11 are tightly contacted (the tooth surfaces of the other side of the meshing gear pair of the first planet gear P11 and the first sun gear S1 are tightly contacted, and the tooth surfaces of the first planet gear P11 and the left side of the meshing gear pair of the first ring gear R1 are tightly contacted in fig. 5); the second sun gear S2 is in contact with the tooth surface of one side of the meshing gear pair of the second planetary gear P21, the second planetary gear P21 is in contact with the tooth surface of the other side of the meshing gear pair of the first ring gear R1 (corresponding to contact between the second sun gear S2 and the left tooth surface of the meshing gear pair of the second planetary gear P21, contact between the second planetary gear P21 and the right tooth surface of the meshing gear pair of the first ring gear R1 in fig. 5), the third planetary gear P12 is in contact with the tooth surface of one side of the meshing gear pair of the second ring gear R2, contact between the fourth planetary gear P22 and the tooth surface of the other side of the meshing gear pair of the second ring gear R2 (corresponding to contact between the third planetary gear P12 and the right tooth surface of the meshing gear pair of the second ring gear R2, contact between the fourth planetary gear P22 and the left tooth surface of the meshing gear pair of the second ring gear R2 in fig. 6).
Specifically, when forward motion is output, the first motor drives the first sun gear S1 to rotate anticlockwise, the second motor drives the second sun gear S2 to follow, and a phase difference equal to a transmission clearance value is kept between the two motors. When the output reverse motion, the second motor drives the second sun gear S2 to rotate clockwise, the first motor drives the first sun gear S1 to follow, a phase difference equal to a transmission clearance value is kept between the two motors, and finally, the forward motion output and the reverse motion output without a transmission clearance can be realized.
As can be seen from the above embodiments of the present invention, the planetary reducer and the integrated joint provided by the present invention have at least the following advantages:
1. the integrated joint provided by the invention adopts two motors to drive through two sets of parallel sun gears, two sets of parallel planet gears, a fixed annular gear (a first annular gear) and a movable annular gear (a second annular gear), and finally realizes the motion output of the movable annular gear without a transmission gap;
2. the integrated joint provided by the invention has the advantages of simple and reasonable structural design, reliable gap elimination, high transmission efficiency and transmission precision, and is an ideal scheme of a humanoid robot or a collaborative robot driving unit;
3. the excellent reverse driving capability of the planetary reducer in the integrated joint can enable the robot to have good flexibility or good interaction capability with the external environment, so that the robot can be prevented from being damaged when being impacted or fallen down, or intrinsically safe man-machine interaction can be ensured when the robot is cooperated with a person; the speed reducer can realize high-efficiency forward and reverse transmission capacity through the arrangement of parameters such as the number of teeth, the displacement coefficient and the like, so that the integrated joint has excellent bidirectional driving capacity.
The planetary reducer and the integrated joint according to the present invention are described above by way of example with reference to fig. 1 to 6. However, it will be appreciated by those skilled in the art that various modifications may be made to the planetary reducer and integrated joint as set forth above without departing from the teachings of the present invention. Accordingly, the scope of the invention should be determined from the following claims.