Rotational joint structure and preparation method thereof, mechanical arm and robot

Abstract

The present application relates to a rotary joint structure and a preparation method thereof, a mechanical arm and a robot, wherein the output flange is fixed on the inner ring of the harmonic reducer bearing; the input encoder disc is installed on the end face of the motor rotor magnetic steel; the output encoder disc sleeve is placed on the straight shaft portion; the output encoder reading circuit board and the input encoder reading circuit board are arranged on the same plane; the torque sensor is connected to the outer ring of the harmonic reducer bearing, the inner ring of the torque sensor is meshed with a section of the harmonic reducer flexible wheel, and the other section of the harmonic reducer flexible wheel is meshed with the inner ring of the harmonic reducer bearing; the support bearing sleeve is placed on the straight shaft portion of the output flange. While forming an input-output closed loop, the space occupied by the encoder is saved; while ensuring that the output torque remains unchanged, the axial size and overall weight of the reducer are greatly reduced; thereby facilitating a significant reduction in the overall size and weight of the rotary joint structure, thereby achieving a smaller size and weight under the same target load capacity.

Description

Technical Field

[0001] The present application relates to the field of joint connection, and in particular to a rotary joint structure and a preparation method thereof, a mechanical arm and a robot. Background Art

[0002] With the rapid development of intelligent manufacturing, the demand for robots in the civilian consumer market and the industrial manufacturing market has also increased rapidly, and the performance requirements have also become increasingly higher. The Chinese patent with the publication number CN107443375A discloses a robot origin calibration method, device, storage medium and computer equipment. The method includes: obtaining the initial joint coordinates corresponding to the initial state of each joint axis of the robot; according to the initial joint coordinates, obtaining the current joint coordinates corresponding to the current state of the joint axis when the robot end approaches the preset reference point in a variety of different postures and coincides with the reference point; according to the current joint coordinates, obtaining the corresponding position coordinates under each posture, and calculating the distance deviation between each position coordinate; when any distance deviation is greater than the preset value, using the search algorithm to update the initial joint coordinates; according to the updated initial joint coordinates, updating the current joint coordinates, entering the step of obtaining the corresponding position coordinates under each posture according to the current joint coordinates, until each distance deviation is less than the preset value, obtaining the corresponding target initial joint coordinates as the origin of the robot, which can not only reduce costs but also improve efficiency.

[0003] In addition, the size, weight, and output torque of the robot joint module directly determine the overall size and operating performance of the robot. Therefore, the size and weight of the joint module used by the robot are required to be smaller and smaller, while the output torque is required to be higher and higher. A conventional robot revolute joint module 100 can also be called a revolute joint structure. Figure 1 and Figure 2 As shown, its length including the brake is about 122 mm, and if the brake is discarded, it is about 86 mm long.

[0004] But specifically, the current market demand for robots is miniaturization and lightness, and the robot joint module, as the core component of the robot, determines the overall size, weight and load capacity of the robot. The traditional solution is mainly to simply stack the main components such as the driver, encoder, motor and reducer, so there are generally problems of large size and heavy weight. Summary of the invention

[0005] Based on this, it is necessary to provide a rotational joint structure and a preparation method thereof, a robotic arm and a robot.

[0006] A method for preparing a rotational joint structure comprises the steps of:

[0007] Install the input encoder disc on the magnetic steel end surface of the motor rotor;

[0008] The output encoder code disc is placed on the straight shaft portion of the output flange, and the reading directions of the input encoder code disc and the output encoder code disc are opposite to each other along the axial direction of the output flange;

[0009] The input encoder reading circuit board and the output encoder reading circuit board are arranged on the same plane;

[0010] Connect the torque sensor to the outer ring of the harmonic reducer bearing;

[0011] Engage one section of the harmonic reducer flexspline with the inner ring of the torque sensor;

[0012] Engage the other section of the harmonic reducer flexspline with the inner ring of the harmonic reducer bearing;

[0013] The camshaft of the harmonic reducer is combined with the rotor shaft of the motor to form an integrated rotor shaft;

[0014] The output flange is fixed on the inner ring of the harmonic reducer bearing, and the straight shaft portion of the output flange passes through the inside of the integrated rotor shaft;

[0015] A support bearing is installed on the straight shaft portion of the output flange to position and support the integrated rotor shaft.

[0016] The preparation method of the above-mentioned rotating joint structure comprehensively considers the structural characteristics and performance requirements of the rotating joint and optimizes them in principle. On the one hand, through the optimized design of the input and output encoder code disk and the reading circuit board thereof, the space occupied by the encoder is saved while forming an input and output closed loop; on the other hand, in conjunction with the connection improvement of the torque sensor, the axial size and overall weight of the reducer are greatly reduced while ensuring the output torque remains unchanged; on the other hand, by designing an integrated rotor shaft, the axial size is further reduced, which is beneficial to greatly reduce the overall size and weight of the rotating joint structure, thereby obtaining a smaller size and weight under the same target load capacity.

[0017] In one embodiment, a revolute joint structure comprises:

[0018] A motor rotor having a motor rotor shaft;

[0019] An output flange is fixed on the inner ring of the harmonic reducer bearing, and the straight shaft portion of the output flange passes through the inside of the motor rotor shaft;

[0020] An input encoder disc is mounted on the magnetic steel end surface of the motor rotor;

[0021] An output encoder code disc is sleeved on the straight shaft portion, and the reading directions of the input encoder code disc and the output encoder code disc are opposite to each other along the axial direction of the output flange;

[0022] Input encoder reading circuit board;

[0023] An output encoder reading circuit board is arranged on the same plane as the input encoder reading circuit board;

[0024] A torque sensor is connected to the outer ring of the harmonic reducer bearing, the inner ring of the torque sensor is meshed with one section of the harmonic reducer flexible wheel, and the other section of the harmonic reducer flexible wheel is meshed with the inner ring of the harmonic reducer bearing; and,

[0025] A support bearing is sleeved on the straight shaft portion of the output flange to position and support the motor rotor shaft.

[0026] The above-mentioned rotating joint structure comprehensively considers the structural characteristics and performance requirements of the rotating joint and optimizes them in principle. Through the optimized design of the input and output encoder code disk and its reading circuit board, while forming an input and output closed loop, the space occupied by the encoder is saved; combined with the connection improvement of the torque sensor, while ensuring the output torque remains unchanged, the axial size and overall weight of the reducer are greatly reduced; this is conducive to greatly reducing the overall size and weight of the rotating joint structure, thereby obtaining a smaller size and weight under the same target load capacity.

[0027] In one embodiment, the inner ring of the torque sensor has machined teeth to mesh with a section of the harmonic reducer flexspline, and the inner ring of the harmonic reducer bearing also has machined teeth to mesh with another section of the harmonic reducer flexspline.

[0028] In one of the embodiments, the rotary joint structure also includes the harmonic reducer; or, further includes the inner ring of the harmonic reducer bearing and the harmonic reducer flexible wheel.

[0029] In one embodiment, the harmonic reducer bearing includes a crossed roller bearing, a four-point contact bearing and a deep groove ball bearing; and / or, the harmonic reducer flexible wheel is a straight-cylinder flexible wheel.

[0030] In one embodiment, the straight shaft portion is hollow; and / or,

[0031] The input encoder reading circuit board and the output encoder reading circuit board are integrally arranged to form an encoder reading board; and / or,

[0032] The input encoder reading circuit board and the output encoder reading circuit board are both arranged between the input encoder code disc and the output encoder code disc; and / or,

[0033] The input encoder reading circuit board and the output encoder reading circuit board are both arranged on the same plane which is perpendicular to the axial direction of the output flange.

[0034] In one embodiment, the number of the support bearings is two, including a first support bearing and a second support bearing, and the first support bearing and the second support bearing are arranged at intervals; and / or,

[0035] The input encoder code disc is mounted on the plane where the end surface of the motor rotor magnetic steel is located, or the installation plane of the input encoder code disc is less than 5 mm from the end surface of the motor rotor magnetic steel; and / or,

[0036] The rotating joint structure also includes a rear cover, a driving seat plate and a shell, and the output flange is arranged through the shell; the motor rotor, the input encoder code disk, the output encoder code disk, the input encoder reading circuit board and the output encoder reading circuit board are all located in the shell, and the support bearing is at least partially located in the shell; the torque sensor and the driving seat plate are respectively fixed at both ends of the shell, the rear cover is fixed on the driving seat plate and the rear cover is provided with a reading window for revealing the input encoder reading circuit board and the output encoder reading circuit board; the output flange is partially located between the torque sensor and the harmonic reducer bearing.

[0037] In one embodiment, the motor rotor shaft of the motor rotor is combined with the harmonic reducer camshaft to form an integrated rotor shaft; or, the motor rotor shaft and the harmonic reducer camshaft are integrally arranged;

[0038] Furthermore, the straight shaft portion of the output flange passes through the inside of the integrated rotor shaft; and the support bearing is used to position and support the integrated rotor shaft.

[0039] In one embodiment, a robotic arm includes any one of the rotational joint structures and two structural members, wherein the two structural members are connected via the rotational joint structure.

[0040] In one embodiment, a robot includes a main body and any one of the robotic arms installed on the main body. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0042] Figure 1 This is a schematic diagram of the structure of a traditional rotational joint module.

[0043] Figure 2 for Figure 1 A schematic diagram of the rotational joint module in another direction is shown.

[0044] Figure 3 It is a structural schematic diagram of an embodiment of the rotary joint structure described in this application.

[0045] Figure 4 for Figure 3 Another schematic diagram of the embodiment shown.

[0046] Figure 5 for Figure 3 A schematic cross-sectional view of one direction of the embodiment shown.

[0047] Figure 6 for Figure 5 An enlarged schematic diagram of point A of the illustrated embodiment.

[0048] Figure 7 for Figure 3 Another oblique cross-sectional view of the illustrated embodiment.

[0049] Figure 8 for Figure 7 An enlarged schematic diagram of point B of the illustrated embodiment.

[0050] Fig. 9 for Figure 7 An enlarged schematic diagram of point C of the illustrated embodiment.

[0051] Fig.10 for Figure 3 A half-section schematic diagram of the embodiment shown in another direction.

[0052] Fig.11 for Figure 3 A half-section schematic diagram of the embodiment shown in another direction.

[0053] Fig.12 for Figure 3 Another schematic diagram of the embodiment shown.

[0054] Fig.13 This is a schematic flow chart of an embodiment of a method for preparing a rotational joint structure described in the present application.

[0055] Reference numerals:

[0056] Rotary joint module 100, rear cover 110, drive base plate 120, housing 130, torque sensor 140, harmonic reducer 150, shaft hole 160, reading window 111, first mounting hole 131, second mounting hole 132, third mounting hole 141, cross roller bearing 151, straight cylinder flexible wheel 152, fourth mounting hole 153, output encoder code disk 210, encoder reading plate 220, input encoder code disk 230, motor rotor 240, first support bearing 250, integrated rotor shaft 260, second support bearing 270, output flange 280, straight shaft portion 281, disk body 282. DETAILED DESCRIPTION

[0057] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0058] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it may be directly on the other component or there may also be a central component. When a component is considered to be "connected to" another component, it may be directly connected to the other component or there may be a central component at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in the specification of this application are for illustrative purposes only and do not represent the only implementation method.

[0059] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0060] In the present application, unless otherwise clearly specified and limited, the first feature "above" or "below" the second feature may be that the first feature is directly in contact with the second feature, or the first feature and the second feature are indirectly in contact through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature may be that the first feature is directly above or obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature "below", "below" and "below" the second feature may be that the first feature is directly below or obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature. Unless otherwise defined, all technical and scientific terms used in the specification of this application have the same meaning as those generally understood by technicians in the technical field of this application. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in the specification of this application includes any and all combinations of one or more related listed items.

[0061] The present application discloses a rotational joint structure, a robotic arm and a robot, which include part of the structure or all of the structure of the following embodiments; that is, the rotational joint structure and its preparation method, the robotic arm and the robot involved in the present application include part of the technical features or all of the following technical features. In one embodiment of the present application, a rotary joint structure includes: a motor rotor, an output flange, an input encoder code disc, an output encoder code disc, an input encoder reading circuit board, an output encoder reading circuit board, a torque sensor and a support bearing; the motor rotor has a motor rotor shaft; the output flange is fixed to the inner ring of the harmonic reducer bearing, and the straight shaft portion of the output flange passes through the inside of the motor rotor shaft; the input encoder code disc is installed on the end surface of the motor rotor magnetic steel; the output encoder code disc sleeve is placed on the straight shaft portion, and the reading directions of the input encoder code disc and the output encoder code disc are opposite along the axial direction of the output flange; the output encoder reading circuit board and the input encoder reading circuit board are arranged on the same plane; the torque sensor is connected to the outer ring of the harmonic reducer bearing, the inner ring of the torque sensor is meshed with a section of the harmonic reducer flexible wheel, and the other section of the harmonic reducer flexible wheel is meshed with the inner ring of the harmonic reducer bearing; the support bearing sleeve is placed on the straight shaft portion of the output flange to position and support the motor rotor shaft. The above-mentioned rotating joint structure comprehensively considers the structural characteristics and performance requirements of the rotating joint and optimizes them in principle. Through the optimized design of the input and output encoder code disk and its reading circuit board, while forming an input and output closed loop, the space occupied by the encoder is saved; combined with the connection improvement of the torque sensor, while ensuring the output torque remains unchanged, the axial size and overall weight of the reducer are greatly reduced; this is conducive to greatly reducing the overall size and weight of the rotating joint structure, thereby obtaining a smaller size and weight under the same target load capacity.

[0062] In one embodiment, a revolute joint structure such as Figure 3 As shown, it includes: a rear cover 110, a driving seat plate 120, a housing 130, a torque sensor 140 and a harmonic reducer 150. The torque sensor 140 and the driving seat plate 120 are respectively fixed to the two ends of the housing 130. The rear cover 110 is fixed to the driving seat plate 120 and the rear cover 110 is provided with a reading window 111 for displaying the internal reading. In other embodiments, the rotary joint structure may not include the harmonic reducer 150. Figure 3 The harmonic reducer 150 shown in the figure may be only a part of its structure, such as a harmonic reducer bearing. In this embodiment, the rotary joint structure is further provided with an axial hole 160, and the axial hole 160 passes through the rear cover 110 or the axial hole 160 passes through the entire rotary joint structure. Such a design, through the cooperation of the torque sensor and the harmonic reducer, forms a harmonic reducer with a torque sensor, which greatly reduces the axial size and overall weight of the reducer while ensuring that the output torque remains unchanged.

[0063] Combination Figure 4 In this embodiment, the rotary joint structure also includes an output flange 280 partially penetrated through the housing 130, the torque sensor 140 and the harmonic reducer 150, and the output flange 280 is hollow, and the shaft hole 160 is set through the output flange 280 to penetrate the rotary joint structure. Furthermore, the output flange 280 is fixed on the rigid wheel of the harmonic reducer 150, and the straight shaft portion of the output flange 280 passes through the inside of the motor rotor shaft or the integrated rotor shaft including the motor rotor shaft. Such a design, combined with the design of the integrated rotor shaft, is conducive to saving the axial dimension of the module occupied by the support bearing, thereby reducing the weight and axial dimension of the module, and is conducive to reducing the axial dimension and overall weight of the reducer under the premise of ensuring that the output torque remains unchanged, thereby reducing the overall size and weight of the rotary joint structure such as the robot joint.

[0064] In one embodiment, the revolute joint structure is as follows Figure 5As shown, it also includes a motor rotor 240, an output flange 280, an input encoder code disc 230, an output encoder code disc 210, an encoder reading plate 220 and a support bearing; wherein the support bearing sleeve is placed on the straight shaft portion 281 of the output flange 280 to position and support the motor rotor shaft; in this embodiment, the number of the support bearings is two, including a first support bearing 250 and a second support bearing 270, and the first support bearing 250 and the second support bearing 270 are arranged at intervals. That is, the input shaft and the output shaft of the rotary joint structure respectively use an encoder, which are the input encoder code disc 230 and the output encoder code disc 210. That is, the straight shaft portion 281 of the output flange 280 is made hollow, and two upper and lower bearings are added to the outer diameter of the motor rotor shaft or the integrated rotor shaft including the motor rotor shaft as the positioning support of the motor rotor shaft or the integrated rotor shaft. Further, the harmonic reducer flexible wheel, such as the straight cylinder flexible wheel 152, is at least partially located between the first support bearing 250 and the second support bearing 270. Such a design is conducive to saving the axial dimension of the module occupied by the support bearing, thereby reducing the weight and axial dimension of the module; and the two support bearings arranged at intervals are conducive to achieving a balance between uniform force distribution and dispersed layout, while saving the space occupied by the encoder, it improves the long-term operating stability of the motor rotor shaft, especially the integrated rotor shaft. Stable and controllable is one of the important requirements of the robot or its mechanical arm for the rotating joint structure.

[0065] In each embodiment, the motor rotor 240 has a motor rotor shaft; the output flange 280 is fixed on the inner ring of the harmonic reducer bearing, and the straight shaft portion 281 of the output flange 280 passes through the inside of the motor rotor shaft; in one embodiment, the straight shaft portion 281 is hollow and used as part or all of the shaft hole 160. In this embodiment, the harmonic reducer bearing is a cross roller bearing 151, and in other embodiments, the harmonic reducer bearing also includes a four-point contact bearing and a deep groove ball bearing. Such a design combines the harmonic reducer as a whole with the rotating joint structure, so that it cooperates with the torque sensor to achieve connection improvement, while ensuring that the output torque remains unchanged, the axial size and overall weight of the reducer are greatly reduced, which is conducive to greatly reducing the overall size and weight of the rotating joint structure, thereby obtaining a smaller size and weight under the same target load capacity.

[0066] Combination Figure 6In this embodiment, the motor rotor shaft of the motor rotor 240 is combined with the camshaft of the harmonic reducer 150 to form an integrated rotor shaft 260; or, the motor rotor shaft and the harmonic reducer camshaft are integrally arranged. In addition, the straight shaft portion 281 of the output flange 280 passes through the inside of the integrated rotor shaft 260; the support bearing is used to position and support the integrated rotor shaft 260, that is, the first support bearing 250 and the second support bearing 270 are used together to position and support the integrated rotor shaft 260. As mentioned above, such a design is conducive to saving the space occupied by the encoder while improving the long-term operation stability of the motor rotor shaft, especially the integrated rotor shaft.

[0067] Combination Figure 7 In this embodiment, the input encoder code disc 230 is installed on the magnetic steel end face of the motor rotor 240; in one of the embodiments, the input encoder code disc 230 is installed on the plane where the magnetic steel end face of the motor rotor 240 is located or the installation plane of the input encoder code disc 230 is less than 5 mm from the magnetic steel end face of the motor rotor 240; that is, the input encoder code disc 230 is installed on the magnetic steel end face of the motor rotor 240, which is not absolutely necessary to be on the plane where the magnetic steel end face of the motor rotor 240 is located, and it can also be appropriately adjusted to cooperate with other structures or have a certain variable position under the premise of reducing the length of the rotating joint structure. In one of the embodiments, the installation plane of the input encoder code disc 230 is 3 mm away from the magnetic steel end face of the motor rotor 240, and the other embodiments are similar and will not be described in detail. Such a design, in principle, comprehensively considers and optimizes the structural characteristics and performance requirements of the rotating joint. The input encoder code disc is installed on the plane where the end face of the motor rotor magnet is located. The plane can also be at any other position within the range of ±5mm of the magnet end face. The output encoder code disc is then mounted on the straight axis of the output flange, forming an input and output closed loop, and saving the space occupied by the encoder, which is beneficial to reducing the overall structural size occupied by the code disc.

[0068] In one embodiment, the output encoder code disc 210 is sleeved on the straight shaft portion 281, and the reading directions of the input encoder code disc 230 and the output encoder code disc 210 are opposite to each other along the axial direction of the output flange 280; it can be understood that the output encoder code disc 210 can be directly sleeved on the straight shaft portion 281, or can be as shown in FIG. Figure 8As shown, the output encoder code disc 210 is fixed on the disc body 282 of the output flange 280, and is sleeved on the straight shaft portion 281 through the disc body 282. Since the reading directions of the input encoder code disc 230 and the output encoder code disc 210 are opposite along the axial direction of the output flange 280, and the reading circuit boards of the two encoders are placed on the same plane, it is beneficial to reduce the overall structural size occupied by the encoder structure. Such a design, in principle, comprehensively considers the structural characteristics and performance requirements of the robot joint and optimizes them. The input encoder code disc is directly installed on the motor rotor, and the output encoder code disc is installed opposite to it, and the reading circuit boards of the two are placed on the same plane. In this way, while forming an input-output closed loop, the space size occupied by the encoder is saved, which is at least 4mm lower than the traditional installation method that is not in the same plane.

[0069] Furthermore, if Figure 7 , Figure 8 and Fig. 9 As shown, the driving seat plate 120 is fixed to the first mounting hole 131 of the housing 130 by screws; the cross roller bearing 151 of the harmonic reducer 150 is provided with a fourth mounting hole 153, the torque sensor 140 is provided with a third mounting hole 141, and the housing 130 is also provided with a second mounting hole 132. The second mounting hole 132, the third mounting hole 141 and the fourth mounting hole 153 are correspondingly arranged so that the cross roller bearing 151, the torque sensor 140 and the housing 130 are fixed by screws. Such a design makes the rotary joint structure easy to assemble and maintain.

[0070] Combination Fig.10 and Fig.11 , the encoder reading board 220 includes an input encoder reading circuit board and an output encoder reading circuit board arranged on the same plane; in one embodiment, the input encoder reading circuit board and the output encoder reading circuit board are integrally arranged to form the encoder reading board 220. In one embodiment, the encoder reading board 220 is arranged between the input encoder code disk 230 and the output encoder code disk 210, that is, the input encoder reading circuit board and the output encoder reading circuit board are both arranged between the input encoder code disk 230 and the output encoder code disk 210. In one embodiment, the input encoder reading circuit board and the output encoder reading circuit board are both arranged on the same plane perpendicular to the axial direction of the output flange 280. As mentioned above, such a design optimizes the structure of the input and output encoder code disks and their reading circuit boards, so that they meet the structural characteristics and performance requirements of the rotary joint, while forming an input and output closed loop, saving the space occupied by the encoder.

[0071] The torque sensor 140 is connected to the outer ring of the harmonic reducer bearing, the inner ring of the torque sensor 140 is meshed with a section of the harmonic reducer flexible wheel, and the other section of the harmonic reducer flexible wheel is meshed with the inner ring of the harmonic reducer bearing; in this embodiment, the harmonic reducer flexible wheel is a straight-cylinder flexible wheel 152 to simplify the structure and ensure meshing. In one embodiment, the inner ring of the torque sensor 140 has machined teeth to mesh with a section of the harmonic reducer flexible wheel, and the inner ring of the harmonic reducer 150 bearing also has machined teeth to mesh with the other section of the harmonic reducer flexible wheel. Such a design, on the one hand, processes teeth on the inner ring of the torque sensor to mesh with the teeth of the harmonic reducer flexspline, which is beneficial to reducing the weight and axial size of the reducer; on the other hand, processes teeth on the inner ring of the reducer cross roller bearing to mesh with the teeth of the harmonic reducer flexspline, which is also beneficial to reducing the weight and axial size of the reducer; on the other hand, adopting a straight-cylinder flexspline as the flexspline of the harmonic reducer is also beneficial to reducing the weight and axial size of the reducer; on the other hand, adopting an integrated rotor shaft design is further beneficial to reducing the weight and axial size of the reducer; through the above-mentioned multiple matching methods, the purpose of overall weight reduction and length shortening is achieved.

[0072] In one embodiment, the rotating joint structure also includes the harmonic reducer 150; in one embodiment, the rotating joint structure also includes the inner ring of the harmonic reducer bearing and the flexible pulley of the harmonic reducer; or, the rotating joint structure also includes the harmonic reducer camshaft, the inner ring of the harmonic reducer bearing and the flexible pulley of the harmonic reducer. In one embodiment, the rotary joint structure also includes a rear cover 110, a drive base plate 120 and a housing 130, and the output flange 280 is arranged through the housing 130; the motor rotor 240, the input encoder code disk 230, the output encoder code disk 210, the encoder reading board 220 including the input encoder reading circuit board and the output encoder reading circuit board are all located in the housing 130, and the support bearings including the first support bearing 250 and the second support bearing 270 are at least partially located in the housing 130; the torque sensor 140 and the drive base plate 120 are respectively fixed at both ends of the housing 130, the rear cover 110 is fixed on the drive base plate 120 and the rear cover 110 is provided with a reading window 111 for exposing the encoder reading board 220 or its input encoder reading circuit board and the output encoder reading circuit board; the output flange 280 is partially located between the torque sensor 140 and the harmonic reducer bearing, such as the cross roller bearing 151. Such a design is conducive to forming a complete rotating joint structure. Through the improved connection structure of the harmonic reducer and the torque sensor, the axial size and overall weight of the reducer are greatly reduced while ensuring the output torque remains unchanged. This is one of the core invention points of each embodiment of the present application.

[0073] The following is a comparative explanation of the improvement effect of the rotational joint structure described in the present application. Furthermore, taking a conventional 17-harmonic reducer with a deadweight of 1kg as an example, compared with a traditional robot joint module, the rotational joint structure described in each embodiment of the present application can also be called an ultra-light joint module, which can reduce the weight to 400g. While keeping the radial dimension of 80mm unchanged, the axial dimension is reduced from the original 26.5mm to 18mm, and at the same time, the rotational joint structure has the function of torque feedback. The above improvements are helpful to greatly reduce the overall size and weight of the robot joint. Taking a conventional 17-joint module without a brake as an example, the rotational joint structure described in the present application is as follows. Fig.12 As shown in the figure, through the optimized design of the input and output encoder code disk and its reading circuit board, combined with the connection improvement of the torque sensor and the connection structure design of the reducer, the dead weight is reduced from 1.6kg of the traditional structure to 850g, that is, the weight is reduced by 46.88%; the radial dimension is 80mm unchanged, and the axial dimension is reduced from 86mm to 63.5mm, which makes it have torque feedback function, making it more applicable; please compare Figure 2The conventional revolute joint module shown is 22.5 mm shorter, or 26.2%, than the structure of about 86 mm in length. As can be seen from the above comparison, the present application greatly reduces the overall size and weight of the robot joint, thereby obtaining a smaller size and weight under the same target load capacity.

[0074] In one embodiment, a robotic arm includes the revolving joint structure and two structural parts described in any embodiment, and the two structural parts are connected by the revolving joint structure. In one embodiment, the two structural parts include an arm part and a rotating part, etc. In one embodiment, the two structural parts are an upper arm part and a lower arm part, respectively. It can be understood that the robotic arm can be used alone or in combination with other structures. In one embodiment, a robot includes a main body and the robotic arm described in any embodiment installed on the main body. Such a design, as mentioned above, is conducive to obtaining a smaller size and weight under the same target load capacity, making the revolving joint structure smaller in size and lighter in weight, thereby reducing the size requirements of the robotic arm or robot using the revolving joint structure at the joint part, which is conducive to improving the structural applicability and scenario applicability of the robotic arm or robot using the revolving joint structure.

[0075] In one of the embodiments, a method for preparing a rotational joint structure includes the following steps: installing an input encoder disc on the magnetic steel end face of a motor rotor; placing an output encoder disc sleeve on the straight shaft portion of an output flange, and the reading directions of the input encoder disc and the output encoder disc are opposite along the axial direction of the output flange; arranging an input encoder reading circuit board and an output encoder reading circuit board on the same plane; connecting a torque sensor to an outer ring of a harmonic reducer bearing; meshing a section of a harmonic reducer flexible wheel with an inner ring of a torque sensor; meshing another section of a harmonic reducer flexible wheel with an inner ring of a harmonic reducer bearing; fixing the output flange on the inner ring of a harmonic reducer bearing, and the straight shaft portion of the output flange passes through the inside of the motor rotor shaft; and installing a support bearing on the straight shaft portion of the output flange to position and support the motor rotor shaft. Further, in one of the embodiments, the method for preparing a rotational joint structure is used to prepare the rotational joint structure described in any embodiment.

[0076] In one embodiment, a method for preparing a revolute joint structure is as follows Fig.13As shown, it includes the following steps: installing the input encoder disc on the magnetic steel end face of the motor rotor; placing the output encoder disc on the straight shaft portion of the output flange, and the reading directions of the input encoder disc and the output encoder disc are opposite along the axial direction of the output flange; arranging the input encoder reading circuit board and the output encoder reading circuit board on the same plane; connecting the torque sensor to the outer ring of the harmonic reducer bearing; meshing one section of the harmonic reducer flexible wheel with the inner ring of the torque sensor; meshing another section of the harmonic reducer flexible wheel with the inner ring of the harmonic reducer bearing; combining the harmonic reducer camshaft with the motor rotor shaft to form an integrated rotor shaft; fixing the output flange on the inner ring of the harmonic reducer bearing, and the straight shaft portion of the output flange passes through the inside of the integrated rotor shaft; installing a support bearing on the straight shaft portion of the output flange to position and support the integrated rotor shaft. The rest of the embodiments are similar and will not be described in detail.

[0077] In one embodiment, the method for preparing the rotational joint structure includes the following steps.

[0078] Step 1: The input shaft and the output shaft of the revolute joint structure respectively use a code disc encoder, which are an input encoder and an output encoder, namely, the output encoder code disc and the input encoder code disc;

[0079] Step 2: Install the input encoder disc on the plane where the motor rotor magnetic steel end face is located. The plane can also be at any other position within the range of ±5mm of the magnetic steel end face. Then, the output encoder disc is mounted on the straight shaft part of the output flange, i.e., the straight shaft part.

[0080] Step 3: Make the reading directions of the input encoder code disc and the output encoder code disc opposite to each other along the axial direction, and place the reading circuit boards of the two encoders, i.e., the output encoder reading circuit board and the input encoder reading circuit board, on the same plane;

[0081] Step 4: Connect the torque sensor to the outer ring of the harmonic reducer cross roller bearing, which can also be a four-point contact bearing, deep groove ball bearing or other types of bearings;

[0082] Step 5: Process teeth on the inner ring of the torque sensor to make it mesh with the flex spline teeth of the harmonic reducer;

[0083] Step 6: Process teeth on the inner ring of the cross roller bearing of the reducer to make it mesh with the flex spline teeth of the harmonic reducer;

[0084] Step 7: Make the reducer flexible wheel into a straight cylinder, one section meshes with the inner ring teeth of the torque sensor, and the other section meshes with the inner ring teeth of the cross roller bearing;

[0085] Step 8: Make the harmonic reducer camshaft and the motor rotor shaft into an integrated rotor shaft;

[0086] Step 9: Fix the module output flange to the inner ring of the cross roller bearing of the harmonic reducer, and the straight shaft part of the output flange passes through the inside of the integrated rotor shaft;

[0087] Step 10: Make the straight shaft part of the output flange hollow, and install two upper and lower bearings on it as positioning supports for the integrated rotor shaft.

[0088] Such a design, in principle, comprehensively considers the structural characteristics and performance requirements of the rotating joint and optimizes them. On the one hand, through the optimized design of the input and output encoder code disk and its reading circuit board, the space occupied by the encoder is saved while forming an input and output closed loop; on the other hand, by cooperating with the improvement of the connection of the torque sensor, the axial size and overall weight of the reducer are greatly reduced while ensuring the output torque remains unchanged; on the other hand, by designing an integrated rotor shaft, the axial size is further reduced, which is beneficial to greatly reduce the overall size and weight of the rotating joint structure, thereby obtaining a smaller size and weight under the same target load capacity.

[0089] It should be noted that other embodiments of the present application also include a rotational joint structure and a preparation method thereof, a robotic arm and a robot that can be implemented by combining the technical features in the above embodiments.

[0090] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0091] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the scope of patent protection of the present application shall be subject to the attached claims.

Claims

1. A method for preparing a revolute joint structure, characterized in that: Includes steps: Install the input encoder disc on the magnetic steel end surface of the motor rotor; The output encoder code disc is placed on the straight shaft portion of the output flange, and the reading directions of the input encoder code disc and the output encoder code disc are opposite to each other along the axial direction of the output flange; The input encoder reading circuit board and the output encoder reading circuit board are arranged on the same plane; Connect the torque sensor to the outer ring of the harmonic reducer bearing; Engage one section of the harmonic reducer flexspline with the inner ring of the torque sensor; Engage the other section of the harmonic reducer flexspline with the inner ring of the harmonic reducer bearing; The camshaft of the harmonic reducer is combined with the rotor shaft of the motor to form an integrated rotor shaft; The output flange is fixed on the inner ring of the harmonic reducer bearing, and the straight shaft portion of the output flange passes through the inside of the integrated rotor shaft; A support bearing is installed on the straight shaft portion of the output flange to position and support the integrated rotor shaft.

2. A revolute joint structure, characterized in that: include: A motor rotor (240) having a motor rotor shaft; An output flange (280) is fixed on the inner ring of the bearing of the harmonic reducer (150), and a straight shaft portion (281) of the output flange (280) passes through the inside of the motor rotor shaft; An input encoder code disc (230) is mounted on the magnetic steel end surface of the motor rotor (240); The output encoder code disc (210) is sleeved on the straight shaft portion (281), and the reading directions of the input encoder code disc (230) and the output encoder code disc (210) are opposite to each other along the axial direction of the output flange (280); Input encoder reading circuit board; An output encoder reading circuit board is arranged on the same plane as the input encoder reading circuit board; A torque sensor (140) is connected to the outer ring of a harmonic reducer (150) bearing, the inner ring of the torque sensor (140) is meshed with one section of a harmonic reducer flexible wheel, and the other section of the harmonic reducer flexible wheel is meshed with the inner ring of the harmonic reducer bearing; and A support bearing is sleeved on the straight shaft portion (281) of the output flange (280) to position and support the motor rotor shaft.

3. The revolute joint structure according to claim 2, characterized in that: The inner ring of the torque sensor (140) has machined teeth for meshing with one section of the harmonic reducer flexible wheel, and the inner ring of the bearing of the harmonic reducer (150) also has machined teeth for meshing with another section of the harmonic reducer flexible wheel.

4. The revolute joint structure according to claim 2, characterized in that: The harmonic reducer bearings include a cross roller bearing (151), a four-point contact bearing and a deep groove ball bearing.

5. The revolute joint structure according to claim 2, characterized in that: The harmonic reducer flexible wheel is a straight-cylinder flexible wheel (152).

6. The revolute joint structure according to claim 2, characterized in that: The straight shaft portion (281) is hollow.

7. The revolute joint structure according to claim 2, characterized in that: The input encoder reading circuit board and the output encoder reading circuit board are integrally arranged to form an encoder reading board (220).

8. The revolute joint structure according to claim 2, characterized in that: The input encoder reading circuit board and the output encoder reading circuit board are both arranged between the input encoder code disc (230) and the output encoder code disc (210).

9. The revolute joint structure according to claim 2, characterized in that: The input encoder reading circuit board and the output encoder reading circuit board are both arranged on the same plane perpendicular to the axial direction of the output flange (280).

10. The revolute joint structure according to claim 2, characterized in that: The number of the support bearings is two, including a first support bearing (250) and a second support bearing (270), and the first support bearing (250) and the second support bearing (270) are arranged at intervals.

11. The revolute joint structure according to claim 2, characterized in that: The input encoder code disc (230) is mounted on a plane where the magnetic steel end surface of the motor rotor (240) is located, or the distance between the mounting plane of the input encoder code disc (230) and the magnetic steel end surface of the motor rotor (240) is less than 5 millimeters.

12. The revolute joint structure according to claim 2, characterized in that: The rotary joint structure further comprises a rear cover (110), a driving seat plate (120) and a housing (130), and the output flange (280) is disposed through the housing (130); The motor rotor (240), the input encoder code disk (230), the output encoder code disk (210), the input encoder reading circuit board and the output encoder reading circuit board are all located in the housing (130), and the support bearing is at least partially located in the housing (130); The torque sensor (140) and the driving base plate (120) are respectively fixed to two ends of the housing (130), the rear cover (110) is fixed to the driving base plate (120), and the rear cover (110) is provided with a reading window (111) for revealing the input encoder reading circuit board and the output encoder reading circuit board; The output flange (280) is partially located between the torque sensor (140) and the harmonic reducer bearing.

13. The revolute joint structure according to any one of claims 2 to 12, characterized in that: The motor rotor shaft of the motor rotor (240) is combined with the cam shaft of the harmonic reducer (150) to form an integrated rotor shaft (260); Furthermore, the straight shaft portion (281) of the output flange (280) passes through the interior of the integrated rotor shaft (260); The support bearing is used for positioning and supporting the integrated rotor shaft (260).

14. The revolute joint structure according to any one of claims 2 to 12, characterized in that: The motor rotor shaft and the cam shaft of the harmonic reducer (150) are arranged integrally.

15. A robotic arm, characterized in that: It comprises the rotational joint structure as claimed in any one of claims 2 to 14 and two structural members, wherein the two structural members are connected via the rotational joint structure.

16. A robot, characterized in that: It comprises a main body and a mechanical arm as claimed in claim 15 mounted on the main body.

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