Linear joint and humanoid robot

Abstract

According to the linear joint and the humanoid robot, the requirement for the external space can be reduced, so that the outer diameter size of the linear joint can be reduced, the size and weight of a motor can be reduced as much as possible while the performance of the motor is guaranteed through a slender motor stator, the overall size of the joint is further controlled, and the joint is more compact. And the linear joint is more compact and light. The device comprises a motor assembly, a ball screw pair, a push rod assembly and a joint shell. The motor assembly and the ball screw pair are both arranged in the joint shell, a lead screw rod in the ball screw pair is placed in a cavity of rotor back iron of the motor assembly, an internal circulation type lead screw nut is placed on the lead screw rod, and the internal circulation type lead screw nut and the rotor back iron are connected to form a rolling body. The lead screw is connected with the push rod assembly. The rotor back iron is used for driving the lead screw nut to rotate, the rotation movement of the lead screw nut drives the lead screw rod to move axially, and the lead screw rod is used for driving the push rod assembly to move linearly.

Description

Technical Field

[0001] The present application relates to the field of intelligent mechanical technology, and in particular to a linear joint and a humanoid robot. Background Art

[0002] In recent years, with the rapid development of humanoid robots, the types of joint actuators used in humanoid robots have continued to increase. Among the joint actuators, motor-driven joints are the main type. The types of electric-driven joints can be divided into rotary joints and linear joints according to the movement mode of the output end. Compared with rotary joints, linear joints can convert the rotational motion of the motor into the linear motion of the push rod, and have higher efficiency and stronger impact resistance. They are more suitable for parts of humanoid robots that require explosive power, such as arms and legs.

[0003] Among the existing linear joint solutions, the telescopic mechanism of some linear joints adopts the planetary roller screw pair solution, while the motor solution of other linear joints uses the frameless torque motor of the traditional rotary joint. Although the above two solutions have their own advantages, if the linear joint adopts the planetary roller screw pair solution, although its load-bearing capacity is relatively high, its mechanism is relatively complex, the manufacturing process is difficult, and the efficiency is relatively low; and the frameless motor of the traditional rotary joint generally has a large outer diameter, resulting in the existing linear joint solutions. The disadvantages of large joint outer diameter and heavy weight, which will cause the linear joint to be used in the forearm and calf of the humanoid robot to control the wrist and ankle. The problem of large outer diameter will make it difficult to store under the shell of the humanoid robot, and it is easy to interfere with the mechanical parts of the humanoid robot, and the overall flexibility and maneuverability are poor.

[0004] Therefore, both of the above-mentioned linear joints have certain defects, which are not conducive to the rapid development and implementation of humanoid robots. Summary of the invention

[0005] The present application provides a linear joint and a humanoid robot for solving the above-mentioned technical problems.

[0006] The present application provides a first aspect of a linear joint, comprising: a motor assembly, a ball screw pair, a push rod assembly and a joint housing;

[0007] The motor assembly and the ball screw pair are both arranged in the joint housing;

[0008] The lead screw in the ball screw pair is placed in the cavity of the rotor back iron of the motor assembly, an internal circulation lead screw nut is placed on the lead screw, and the internal circulation lead screw nut is connected with the rotor back iron to form a rolling body;

[0009] The lead screw is connected to the push rod assembly;

[0010] The rotor back iron is used to drive the lead screw nut to rotate, and the rotational movement of the lead screw nut drives the lead screw to move axially, and the lead screw is used to drive the push rod assembly to move linearly.

[0011] Optionally, the motor assembly includes a motor stator, a rotor back iron and a motor magnetic steel;

[0012] The motor stator is arranged inside the motor housing in the joint housing and is fixedly connected to the inside of the motor housing;

[0013] The rotor back iron is arranged inside the motor stator, and an internal cavity is arranged on the rotor back iron, and the internal cavity is used to place the lead screw;

[0014] The motor magnetic steel is arranged between the motor stator and the rotor back iron, and the motor magnetic steel is connected to the outer surface of the rotor back iron.

[0015] Optionally, the inner circulation type lead screw nut on the ball screw pair is coaxially connected to the rotor back iron to form the rolling element, and the lead screw nut and the rotor back iron are fixed by glue or interference connection.

[0016] Optionally, a pair of double-row angular contact ball bearings are installed at the positioning end of the rolling body, the inner ring of the double-row angular contact ball bearing is fixed to the outer surface of the screw nut, the outer ring of the double-row angular contact ball bearing is provided with an external thread, the double-row angular contact ball bearing is connected to the locking nut via the external thread, and the locking nut is used to pre-tighten the inner ring of the double-row angular contact ball bearing.

[0017] Optionally, a thin deep groove ball bearing is installed at the floating end of the rolling body, the inner ring of the thin deep groove ball bearing is fixed to the outer protruding end of the shaft of the rotor back iron, and the outer ring of the thin deep groove ball bearing is connected to a wave spring.

[0018] Optionally, the push rod assembly is a ball spline pair, the ball spline pair includes a push rod and a spline sleeve, the push rod is provided with a groove, the groove is axially arranged, and the spline sleeve is connected with the groove through a steel ball, so that the push rod performs linear motion;

[0019] The spline sleeve is installed on the concentric inner circle of the front end cover in the joint housing. The front end cover is provided with a concentric boss. The front end cover is sleeve-connected with the inner circle of the motor housing through the concentric boss.

[0020] Optionally, a concentric blind hole is provided at the upper end of the push rod, an internal thread is provided at the lower portion of the concentric blind hole, an external screw having a diameter smaller than the outer circle of the lead screw and a positioning plane is provided at the lower end of the lead screw, and a smooth rod portion is provided on the external screw.

[0021] Optionally, upper limit plates and lower limit plates are provided at both ends of the lead screw, the upper limit plate is fixed to the rear end face of the lead screw by screws, the lower limit plate is embedded in the bare rod part of the lead screw, and the lower limit plate is fixed to the positioning plane of the lead screw by a fixed push rod.

[0022] Optionally, the linear joint further includes an encoder component, wherein the encoder component is disposed at one end of the rolling body, and the encoder component is used to convert the angular displacement of the rolling body into an electrical signal.

[0023] Optionally, the linear joint also includes a tension and pressure sensor, which is electrically connected to the motor driver, one end of the tension and pressure sensor is connected to the rear end cover in the joint housing via an external thread, and the rear end cover is connected to the motor housing via screws.

[0024] Optionally, the linear joint further includes a rod end bearing, and the rod end bearing is respectively connected and fixed to the push rod and the tension and pressure sensor.

[0025] A second aspect of the present application provides a humanoid robot, wherein the humanoid robot is applied with a linear joint as described in the first aspect and any one of the first aspects.

[0026] It can be seen from the above technical solutions that this application has the following advantages:

[0027] 1. As a transmission mechanism, the ball screw pair can convert the rotational motion of the motor into linear motion. It has the characteristics of high precision, high efficiency and high rigidity. Together with the spline shaft, it can ensure that the push rod will not rotate during the linear motion, thereby maintaining the stability and positioning accuracy of the push rod, so that the linear joint can efficiently and accurately realize the telescopic action.

[0028] 2. The direct connection between the screw nut and the inner ring of the fixed-end rolling bearing enhances the rigidity of the transmission system and reduces deformation and vibration during the transmission process. In addition, since the screw nut is farther away from the floating-end bearing, the transmission system is more stable and the error caused by bearing floating is reduced.

[0029] 3. The present application can reduce the need for external space, thereby helping to reduce the outer diameter of the linear joint. The slender motor stator can minimize the size and weight of the motor while ensuring the motor performance, further controlling the overall size of the joint and making the linear joint more compact and lightweight.

[0030] 4. The separate setting of the push rod and the lead screw allows them to be manufactured and optimized independently, improving manufacturing flexibility and efficiency. The push rod and the joint housing are made of light metal materials, which can significantly reduce the weight of the joint, making the linear joint lighter, easier to install and move. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the overall structure of a linear joint provided by the present application;

[0032] Figure 2 is a cross-sectional view of a linear joint provided by the present application;

[0033] Figure 3 It is a schematic diagram of the structure of the separate ball screw pair and ball spline pair provided in this application. DETAILED DESCRIPTION

[0034] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only used to illustrate the relative positional relationships between the various components or components, and do not particularly limit the specific installation orientations of the various components or components.

[0035] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0036] In addition, the terms "installed", "set", "provided with", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0037] In addition, the structures, proportions, sizes, etc. drawn in the drawings in the present application are only used to match the contents disclosed in the specification for the technical personnel in this field to understand and read, and are not used to limit the restrictive conditions under which the present application can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in the present application without affecting the effects and purposes that can be achieved by the present application.

[0038] The following will be combined with the drawings in this application to clearly and completely describe the technical solutions in this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0039] See also Figures 1 to 3 The present application provides a first aspect, which provides a linear joint, including: a motor assembly 10, a ball screw pair 20, a push rod assembly 30 and a joint housing 70; the motor assembly 10 and the ball screw pair 20 are both arranged in the joint housing 70; the lead screw 21 in the ball screw pair 20 is placed in the cavity of the rotor back iron 12 of the motor assembly 10, and an internal circulation type lead screw nut 22 is placed on the lead screw 21, and the internal circulation type lead screw nut 22 is connected to the rotor back iron 12 to form a rolling body; the lead screw 21 is connected to the push rod assembly 30; the rotor back iron 12 is used to drive the lead screw nut 22 to rotate, and the rotational movement of the lead screw nut 22 drives the lead screw 21 to move axially, and the lead screw 21 is used to drive the push rod assembly 30 to move linearly.

[0040] First, the functions and effects of each component in this application are introduced:

[0041] Motor assembly 10: As the power source of the entire linear joint, it provides rotational power. The rotor in the motor assembly 10 will generate a rotational torque after being energized. The rotational torque is the basis for driving the movement of the entire linear joint. The rotor back iron 12, as a part of the rotor, not only supports the rotor structure, but also provides a cavity for accommodating the internal circulation screw nut 22 and the screw 21 in the ball screw pair 20.

[0042] Ball screw pair 20: converts the rotational motion of the motor into linear motion. Among them, the lead screw 21 is the moving part of the ball screw pair 20, and its surface is processed with spiral grooves, which are used to cooperate with the balls in the internal circulation lead screw nut 22 to realize the conversion from rotational motion to linear motion. Balls are installed inside the internal circulation lead screw nut 22, and the balls circulate and roll inside the nut, reducing friction and wear and improving transmission efficiency. The nut is connected to the rotor back iron 12 to form a rolling body, which rotates with the rotor.

[0043] Push rod assembly 30: transmits linear motion to achieve extension or retraction of the joint, wherein the push rod assembly 30 is connected to the lead screw 21. When the lead screw 21 moves axially, the push rod assembly 30 also moves accordingly, thereby achieving the extension or retraction function of the linear joint.

[0044] Joint housing 70: used to support and protect the internal components of the joint. The joint housing 70 provides installation space for the motor assembly 10, the ball screw assembly 20 and the push rod assembly 30, and protects these components from interference and damage from the external environment. At the same time, the housing also plays a role in fixing and positioning, ensuring the stability and reliability of the joint during operation.

[0045] Overall working principle of linear joint:

[0046] When the motor assembly 10 is energized, the rotor generates a rotational torque, which is transmitted to the inner-circulation lead screw nut 22 through the rotor back iron 12. The inner-circulation lead screw nut 22 starts to rotate driven by the rotor, and the balls inside it cooperate with the spiral grooves of the lead screw 21 to convert the rotational motion into axial movement of the lead screw 21. During the axial movement of the lead screw 21, the motion is transmitted to the push rod assembly 30, and the push rod assembly 30 performs linear motion accordingly to achieve the extension or retraction of the joint.

[0047] Therefore, it can be known that the linear joint of the present application provides power through the motor assembly 10, the ball screw pair 20 converts the rotational motion into linear motion, the push rod assembly 30 transmits the linear motion, and the joint housing 70 supports and protects the internal components, thereby achieving efficient, stable and reliable linear motion output. It can also reduce the demand for external space, thereby helping to reduce the outer diameter of the linear joint. The slender motor stator 11 can minimize the size and weight of the motor while ensuring the performance of the motor, further controlling the overall size of the joint, making the linear joint more compact and lightweight.

[0048] Optionally, the motor assembly 10 includes a motor stator 11, a rotor back iron 12 and a motor magnet 13; the motor stator 11 is arranged inside the motor housing 71 in the joint housing 70 and is fixedly connected to the inside of the motor housing 71; the rotor back iron 12 is arranged inside the motor stator 11, and an internal cavity is arranged on the rotor back iron 12, and the internal cavity is used to place the lead screw 21; the motor magnet 13 is arranged between the motor stator 11 and the rotor back iron 12, and the motor magnet 13 is connected to the outer surface of the rotor back iron 12.

[0049] In the embodiment of the present application, the motor stator 11 is an elongated stator, which is fixed inside the motor housing 71 and can be firmly connected to the motor housing 71 by adhesive or other fixing methods. No specific restrictions are made here and it can be set according to actual conditions.

[0050] The motor stator 11 is the stationary part of the motor assembly 10. When powered, the winding generates a magnetic field, which interacts with the magnetic field generated by the rotor back iron 12 and the motor magnet 13, thereby generating a rotational torque. The rotor back iron 12 is arranged inside the motor stator 11, and an internal cavity is arranged on the rotor back cavity. The internal cavity is used to place the lead screw 21, which can provide space for the lead screw to axially expand and contract.

[0051] Among them, the motor magnet 13 is arranged between the motor stator 11 and the rotor back iron 12, and the motor magnet 13 is fixed on the outer surface of the rotor back iron 12 by glue. The motor magnet 13 can be single-segment or multi-segment, which is not specifically limited in the present application and can be set according to actual conditions. The motor magnet 13 can provide a permanent magnetic field, which interacts with the magnetic field generated by the stator winding, thereby generating a rotational torque.

[0052] The slender size of the motor assembly 10 fully utilizes the axial space of the linear joint, reduces the radial size of the linear joint, and at the same time increases the contact area between the motor stator 11 and the motor housing 71, which is beneficial to the rapid heat dissipation of the motor.

[0053] Specifically, in actual applications, when the motor assembly 10 is energized, the windings in the motor stator 11 generate a rotating magnetic field, and this rotating magnetic field interacts with the permanent magnetic field formed by the motor magnet 13 and the rotor back iron 12 to generate a magnetic torque. Under the action of the magnetic torque, the rotor back iron 12 begins to rotate. Since the rotor back iron 12 is connected to the internal circulation type lead screw nut 22, the rotation of the rotor back iron 12 will drive the lead screw nut 22 to rotate. The rotational motion of the lead screw nut 22 is converted into the axial movement of the lead screw 21 through the cooperation of the ball and the lead screw 21. Finally, the axial movement of the lead screw 21 is transmitted to the push rod assembly 30 to realize the extension or retraction of the linear joint.

[0054] Optionally, the inner circulation type lead screw nut 22 on the ball screw pair 20 is coaxially connected to the rotor back iron 12 to form the rolling body, and the lead screw nut 22 and the rotor back iron 12 are fixed by glue or interference connection.

[0055] In the embodiment of the present application, the coaxial connection means that the central axis of the internal circulation screw nut 22 completely coincides with the central axis of the rotor back iron 12. The coaxial connection can ensure that no eccentric force will be generated during the transmission of the rotational torque, thereby reducing vibration and improving the smoothness and accuracy of the transmission.

[0056] Among them, using glue to bond the inner circulation type lead screw nut 22 and the rotor back iron 12 together can ensure a firm connection between the two. The connection and fixation by glue is simple and convenient to operate, and can maintain good coaxiality.

[0057] Among them, it can also be fixed by interference connection. Interference connection is a method of achieving tight connection through interference fit between parts. To achieve interference connection between the screw nut 22 and the rotor back iron 12, the outer diameter of the internal circulation screw nut 22 must be larger than the inner diameter of the rotor back iron 12. The two can be tightly combined together by pressing. The advantages of interference connection are high connection strength, good impact resistance and vibration performance.

[0058] Optionally, a pair of double-row angular contact ball bearings 5 ​​are installed at the positioning end of the rolling body, the inner ring of the double-row angular contact ball bearing 5 is fixed to the outer surface of the screw nut 22, the outer ring of the double-row angular contact ball bearing 5 is provided with an external thread, the double-row angular contact ball bearing 5 is connected to the locking nut 51 via the external thread, and the locking nut 51 is used to pre-tighten the inner ring of the double-row angular contact ball bearing 5.

[0059] In the embodiment of the present application, the double-row angular contact ball bearing 5 is a bearing capable of bearing combined radial and axial loads, capable of bearing axial forces from two directions at the same time, and has high rigidity and precision.

[0060] In the linear joint of the present application, the double-row angular contact ball bearing 5 is installed at the positioning end of the rolling body, and its function is to support and position the screw nut 22, while bearing the radial and axial loads transmitted by the screw nut 22, ensuring the stability and accuracy of the rolling body during rotation.

[0061] The inner ring of the double-row angular contact ball bearing 5 is fixed to the outer surface of the screw nut 22 , which ensures a tight connection between the inner ring of the double-row angular contact ball bearing 5 and the screw nut 22 , so that the double-row angular contact ball bearing 5 can accurately transmit the rotational motion of the screw nut 22 .

[0062] The outer ring of the double-row angular contact ball bearing 5 is provided with an external thread, and the external thread is provided to cooperate with the locking nut 51, so that the locking nut 51 can be screwed on the outer ring of the bearing to achieve pre-tightening of the inner ring of the bearing.

[0063] Therefore, in the linear joint of the present application, by installing a pair of double-row angular contact ball bearings 5 ​​at the positioning end of the rolling body and pre-tightening the inner ring of the bearing through the locking nut 51, the rigidity and stability of the linear joint can be effectively improved, ensuring the accuracy and reliability of the rolling body during rotation.

[0064] Optionally, a thin deep groove ball bearing 6 is installed at the floating end of the rolling body, the inner ring of the thin deep groove ball bearing 6 is fixed to the outer end of the shaft of the rotor back iron 12, and the outer ring of the thin deep groove ball bearing 6 is connected to the wave spring 61.

[0065] In the embodiment of the present application, the thin deep groove ball bearing 6 is installed at the floating end of the rolling element to play a supporting and positioning role, and can withstand radial and a certain degree of axial loads to ensure the stability and accuracy of the rolling element during operation.

[0066] Among them, the inner ring of the thin deep groove ball bearing 6 is fixed to the outer end of the shaft of the rotor back iron 12, which means that when the rotor back iron 12 rotates, it will drive the inner ring of the bearing to rotate together, and then transmit the motion to the outer ring through the bearing.

[0067] The outer ring of the thin deep groove ball bearing 6 is not directly fixed on the joint housing 70 or other fixed components, but is connected to the wave spring 61. By connecting with the wave spring 61, the concentricity of the rolling element and the motor stator 11 can be better guaranteed, and it is also beneficial to reduce the radial runout of the shaft extension end of the rotor back iron 12.

[0068] Optionally, the push rod assembly 30 is a ball spline pair, which includes a push rod 31 and a spline sleeve 32. The push rod 31 is provided with a groove 313, and the groove 313 is axially arranged. The spline sleeve 32 is matched and connected with the groove 313 through a steel ball so that the push rod 31 can move linearly; the spline sleeve 32 is installed on the concentric inner circle of the front end cover 72 in the joint housing 70, and the front end cover 72 is provided with a concentric boss 721, and the front end cover 72 is connected with the inner circle of the motor housing 71 through the concentric boss 721.

[0069] In the embodiment of the present application, the push rod 31 is the main moving component of the ball spline pair, and a groove 313 is arranged on its surface along the axial direction. The groove 313 cooperates with the steel ball of the spline sleeve 32, so that the push rod 31 can move in a straight line. Moreover, because it is rolling friction, the friction force generated by the relative motion is very small. The torque of the push rod 31 can be transmitted by fixing the spline sleeve 32, thereby achieving the purpose of preventing the push rod 31 from rotating.

[0070] Among them, the spline sleeve 32 is sleeved on the push rod 31, and a steel ball is installed inside the spline sleeve 32. The steel ball rolls between the spline sleeve 32 and the groove 313 of the push rod 31, which not only reduces friction but also ensures the accuracy and stability of transmission. The groove 313 on the push rod 31 is axially arranged, and rolling contact is formed between the steel ball on the spline sleeve 32 and the groove 313 of the push rod 31, which greatly reduces friction resistance and improves transmission efficiency. In addition, the steel ball can also withstand certain radial and axial loads, thereby enhancing the bearing capacity of the push rod assembly 30.

[0071] Among them, the spline sleeve 32 can be installed at the concentric inner circle of the front end cover 72 in the joint housing 70, and a concentric boss 721 is provided on the front end cover 72. The concentric boss 721 is used to be sleeved and connected with the inner circle of the motor housing 71. Through the sleeved connection between the concentric boss 721 and the inner circle of the motor housing 71, the front end cover 72 is firmly fixed on the motor housing 71, thereby ensuring the stable installation and accurate positioning of the spline sleeve 32.

[0072] The push rod assembly 30 is set as a ball spline pair, which not only realizes the efficient transmission of linear motion, but also improves the accuracy and stability of transmission. At the same time, the spline sleeve 32 is connected with the motor housing 71 through the front cover 72, ensuring the stable installation and accurate positioning of the entire push rod assembly 30 in the joint housing 70.

[0073] Optionally, the upper end of the push rod 31 is provided with a concentric blind hole 311, the lower part of the concentric blind hole 311 is provided with an internal thread 312, the lower end of the lead screw 21 is provided with an external screw 211 with a diameter smaller than the outer circle of the lead screw and a positioning plane 213, and the external screw 211 is provided with a smooth rod portion 212.

[0074] In the embodiment of the present application, a concentric blind hole 311 is provided at the upper end of the push rod 31, and the concentric blind hole 311 is concentric with the axis of the push rod 31 to ensure the centration and stability during connection, wherein the concentric blind hole 311 is used to accommodate the lower end portion of the lead screw 21 to provide space for the connection between the two, and an internal thread 312 is provided at the lower portion of the concentric blind hole 311, and the internal thread 312 in the concentric blind hole 311 cooperates with the external screw 211 at the lower end of the lead screw 21, and by rotating the lead screw 21, it can be firmly fixed on the push rod 31, thereby realizing the connection between the push rod 31 and the lead screw 21.

[0075] An outer screw 211 with a diameter smaller than the outer circle of the lead screw is provided at the lower end of the lead screw 21. The outer screw 211 is used to cooperate with the inner thread 312 in the concentric blind hole 311 of the push rod 31. A positioning plane 213 is provided below the outer screw 211. The positioning plane 213 is used to ensure the correct position relationship between the lead screw 21 and the push rod 31 during connection to prevent relative rotation or displacement.

[0076] Among them, a locking flat 314 is provided on the push rod 31, and a cross groove 214 is provided on the end face of the ball screw. The two cooperate to ensure that the threaded connection reaches the required locking torque. The push rod 31 is made of light alloy material to reduce weight.

[0077] Specifically, when connecting, first insert the lower end of the lead screw 21 into the concentric blind hole 311 of the push rod 31, ensure that the positioning plane 213 is aligned with the corresponding part of the push rod 31, and then rotate the lead screw 21 to make the thread on the external screw 211 cooperate with the internal thread 312 in the concentric blind hole 311 of the push rod 31, and gradually tighten the connection between the two. Through the cooperation of the threaded connection and the positioning plane 213, a stable connection and reliable transmission between the push rod 31 and the lead screw 21 can be ensured.

[0078] Optionally, an upper limit plate 23 and a lower limit plate 24 are provided at both ends of the lead screw 21, the upper limit plate 23 is fixed to the rear end face of the lead screw 21 by a screw 25, the lower limit plate 24 is embedded in the bare rod portion 212 of the lead screw 21, and the lower limit plate 24 is fixed to the positioning plane 213 of the lead screw 21 by a fixed push rod 31.

[0079] In the embodiment of the present application, the upper limit plate 23 is installed on the rear end face of the lead screw 21. This fixing method ensures the stability of the upper limit plate 23 and prevents it from loosening or falling off during the movement of the lead screw 21. When the lead screw 21 moves downward, the upper limit plate 23 can contact the upper end face of the lead screw nut 22, thereby blocking the further downward movement of the lead screw 21 and preventing the lead screw 21 from separating from the lead screw nut 22.

[0080] The lower stopper 24 is a hollow pancake-shaped block, which is embedded in the bare rod portion 212 of the lead screw and fixed on the positioning plane 213 of the lead screw 21 by the fixed push rod 31. When the ball screw moves upward, the lower stopper 24 can contact the lower end surface of the lead screw nut 22, thereby blocking the further upward movement of the lead screw 21 and preventing the lead screw from being separated from the lead screw nut 22.

[0081] It should be noted that, in a specific application, the lower limit plate 24 may also be replaced by an elastic retaining spring for the shaft.

[0082] Optionally, the linear joint further includes an encoder component 40, which is disposed at one end of the rolling body, and the encoder component 40 is used to convert the angular displacement of the rolling body into an electrical signal.

[0083] In the embodiment of the present application, in order to accurately control the position of the extension and retraction of the push rod 31, the linear joint also includes an encoder component 40, which is arranged at one end of the rolling body, and is used to convert the angular displacement of the rolling body into an electrical signal and feed it back to the motor driver. The motor driver can output a control instruction to the motor according to the current angle of the rolling body to adjust and correct the output angle of the rotating shaft. In specific applications, the encoder can be a photoelectric encoder, a magnetoelectric encoder, etc.

[0084] Preferably, in the embodiment of the present application, the encoder is a magnetic encoder, and a concentric step is provided at the axial extension end of the rotor back iron 12. The magnet 41 is concentrically fixed to the adapter 42 by glue, and the adapter 42 is concentrically fixed to the concentric step of the rotor back iron 12 by glue to ensure the concentricity of the magnet 41 and the rolling body, and the encoder stator 43 is installed on the mounting plane of the motor housing 71.

[0085] Therefore, by introducing the encoder assembly 40 into the linear joint, accurate measurement and conversion of the angular displacement of the rolling body can be achieved, providing support for precise positioning, closed-loop control and state monitoring of the linear joint, thereby making the performance of the linear joint more perfect.

[0086] Optionally, the linear joint also includes a tension pressure sensor 8, which is electrically connected to the motor driver. One end of the tension pressure sensor 8 is connected to the rear end cover 73 in the joint housing 70 through an external thread, and the rear end cover 73 is connected to the motor housing 71 through a screw 25.

[0087] In the embodiment of the present application, in order to accurately control the force of the extension and retraction of the push rod 31, the linear joint also includes a tension and pressure sensor 8, and external threads are provided at both ends of the tension and pressure sensor 8, one end of which is connected to the rear end cover 73, and the rear end cover 73 is fixed to the motor housing 71 by a screw 25, thereby being connected to the fixed end of the linear joint, and is used to detect the axial force borne by the linear joint, and the tension and pressure sensor 8 is also electrically connected to the motor driver.

[0088] By integrating the tension and pressure sensor 8 into the linear joint, and connecting the rear end cover 73 through external threads and the rear end cover 73 and the motor housing 71 through screws 25, the force in two directions of the joint can be detected, thereby achieving real-time monitoring and control of the pressure.

[0089] Optionally, the linear joint further includes a rod end bearing 90 , and the rod end bearing 90 is respectively connected and fixed to the push rod 31 and the tension and pressure sensor 8 .

[0090] In the embodiment of the present application, the telescopic end and the fixed end of the linear joint are also provided with a rod end bearing 90, and the rod end bearing 90 is integrated with an integrated connecting rod 91 and a joint bearing 92. The connecting rod 91 is provided with an internal thread 312, and the telescopic end of the linear joint is fixedly connected to the end external thread of the push rod 31 through the external thread of the push rod 31, and the fixed end of the linear joint is fixedly connected to the tension and pressure sensor 8 through the external thread.

[0091] Among them, the locking depth and fixing angle of the rod end bearing 90 can be adjusted by a thin external hexagonal nut 93 at the telescopic end of the linear joint. When the rod end bearing 90 is used in pairs, it can ensure that the telescopic end and the fixed end of the linear joint are hinged, thereby avoiding the linear joint from being subjected to bending moment to the greatest extent, causing the push rod 31 to bend.

[0092] A second aspect of the present application provides a humanoid robot, wherein the humanoid robot is applied with a linear joint as described in the first aspect and any one of the first aspects.

[0093] It should be noted that the above description of the disclosed embodiments enables professionals and technicians in the field to implement or use the present application. Various modifications to these embodiments will be apparent to professionals and technicians in the field, and the general principles defined herein can be implemented in other embodiments without departing from the scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but should conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A linear joint, characterized in that: include: Motor assembly, ball screw pair, push rod assembly and joint housing; The motor assembly and the ball screw pair are both arranged in the joint housing; The lead screw in the ball screw pair is placed in the cavity of the rotor back iron of the motor assembly, an internal circulation lead screw nut is placed on the lead screw, and the internal circulation lead screw nut is connected with the rotor back iron to form a rolling body; The lead screw is connected to the push rod assembly; The rotor back iron is used to drive the lead screw nut to rotate, and the rotational movement of the lead screw nut drives the lead screw to move axially, and the lead screw is used to drive the push rod assembly to move linearly.

2. The linear joint according to claim 1, characterized in that: The motor assembly includes a motor stator, a rotor back iron and a motor magnetic steel; The motor stator is arranged inside the motor housing in the joint housing and is fixedly connected to the inside of the motor housing; The rotor back iron is arranged inside the motor stator, and an internal cavity is arranged on the rotor back iron, and the internal cavity is used to place the lead screw; The motor magnetic steel is arranged between the motor stator and the rotor back iron, and the motor magnetic steel is connected to the outer surface of the rotor back iron.

3. The linear joint according to claim 2, characterized in that: The inner circulation type lead screw nut on the ball screw pair is coaxially connected with the rotor back iron to form the rolling body, and the lead screw nut and the rotor back iron are fixed by glue or interference connection.

4. The linear joint according to claim 3, characterized in that: A pair of double-row angular contact ball bearings are installed at the positioning end of the rolling body, the inner ring of the double-row angular contact ball bearing is fixed to the outer surface of the screw nut, the outer ring of the double-row angular contact ball bearing is provided with an external thread, the double-row angular contact ball bearing is connected to the locking nut via the external thread, and the locking nut is used to pre-tighten the inner ring of the double-row angular contact ball bearing.

5. The linear joint according to claim 3, characterized in that: A thin deep groove ball bearing is installed at the floating end of the rolling body, the inner ring of the thin deep groove ball bearing is fixed to the outer extension end of the shaft of the rotor back iron, and the outer ring of the thin deep groove ball bearing is connected to a wave spring.

6. The linear joint according to claim 2, characterized in that: The push rod assembly is a ball spline pair, and the ball spline pair includes a push rod and a spline sleeve. The push rod is provided with a groove, and the groove is axially arranged. The spline sleeve is connected with the groove through a steel ball, so that the push rod can perform linear motion; The spline sleeve is installed on the concentric inner circle of the front end cover in the joint housing. The front end cover is provided with a concentric boss. The front end cover is sleeve-connected with the inner circle of the motor housing through the concentric boss.

7. The linear joint according to claim 6, characterized in that: The upper end of the push rod is provided with a concentric blind hole, the lower part of the concentric blind hole is provided with an internal thread, the lower end of the lead screw is provided with an outer screw with a diameter smaller than the outer circle of the lead screw and a positioning plane, and a polished rod portion is provided on the outer screw.

8. The linear joint according to claim 7, characterized in that: An upper limit plate and a lower limit plate are provided at both ends of the lead screw, the upper limit plate is fixed to the rear end face of the lead screw by screws, the lower limit plate is embedded in the bare rod part of the lead screw, and the lower limit plate is fixed to the positioning plane of the lead screw by a fixed push rod.

9. The linear joint according to claim 3, characterized in that: The linear joint further comprises an encoder component, which is arranged at one end of the rolling body and is used for converting the angular displacement of the rolling body into an electrical signal.

10. The linear joint according to claim 6, characterized in that: The linear joint also includes a tension pressure sensor, which is electrically connected to the motor driver. One end of the tension pressure sensor is connected to the rear end cover in the joint housing through an external thread, and the rear end cover is connected to the motor housing through a screw.

11. The linear joint according to claim 10, characterized in that: The linear joint further comprises a rod end bearing, and the rod end bearing is respectively connected and fixed to the push rod and the tension and pressure sensor.

12. A humanoid robot, characterized in that: The humanoid robot is applied with the linear joint according to any one of claims 1 to 11.

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