Linear actuator and bionic hand

Abstract

The utility model discloses a linear actuator and bionic manipulator relates to robot technical field, wherein, linear actuator includes the casing and is equipped with two drive mechanisms at its first end. Each drive mechanism contains rotating electrical machines, drive shaft and transmission mechanism, and drive shaft is retractable along the first direction and is provided, and transmission mechanism converts motor rotary motion into drive shaft linear motion. Two drive shaft output difference settings are arranged to adapt to the demand of different crank length in bionic manipulator to driving torque. Through integration double drive in single casing, compact structure, and high space utilization rate, the differentiation output design promotes the driving matching precision and control flexibility, satisfies the requirement of multi -freedom degree cooperation drive, realizes the bionic drive of high integration degree, high efficiency.

Description

Technical Field

[0001] This utility model relates to the field of robotics technology, and in particular to a linear actuator and a bionic robotic hand. Background Technology

[0002] Linear actuators, as electromechanical devices that convert the rotary motion of a motor into linear motion, are widely used in industrial automation, robotics, precision instruments, and medical equipment. With increasingly complex application requirements, especially in multi-axis collaborative operation scenarios, higher demands are placed on the integration and performance of actuators. To meet the growing demand for active degrees of freedom in bionic mechanisms such as dexterous hands, multiple independent linear actuators are typically required. However, arranging multiple actuators in parallel can lead to structural redundancy, low space utilization, significantly increased system size and complexity, and difficulties in installation and maintenance. Furthermore, within confined spaces, the lengths of the drive cranks are often inconsistent, resulting in varying requirements for drive torque.

[0003] In existing technologies, it is difficult to achieve both a compact structure and the independence and differentiated torque output capabilities of multiple outputs. Therefore, there is an urgent need for a multi-path linear drive mechanism with high integration, compact layout, and adaptability to different load requirements to solve the technical challenges of large drive unit size and poor adaptability in multi-degree-of-freedom systems. Utility Model Content

[0004] The main purpose of this invention is to propose a linear actuator and a bionic manipulator, which aims to solve the problems of large size and poor adaptability of the drive unit in a multi-degree-of-freedom system.

[0005] To achieve the above objectives, the present invention proposes a linear actuator for a bionic robotic arm, the linear actuator comprising:

[0006] The housing has a first end located in a first direction; and,

[0007] Two drive mechanisms, each drive mechanism comprising:

[0008] A rotary motor is located inside the housing;

[0009] A drive shaft, extending along the first direction and movably and telescopically disposed at the first end of the housing along the first direction; and,

[0010] A transmission mechanism is provided, which drives the rotating shaft of the rotary motor to the drive shaft, and is used to convert the rotational motion of the rotating shaft of the rotary motor into the linear motion of the drive shaft.

[0011] The output force difference between the two drive shafts of the two drive mechanisms is set.

[0012] In one embodiment, each of the transmission mechanisms includes:

[0013] A gear set, comprising a plurality of gears connected in a transmission manner, wherein the plurality of gears includes at least an input gear and an output gear, the input gear being coaxially connected to the shaft of the rotary motor; and,

[0014] A lead screw drive structure includes a lead screw and a drive nut. The lead screw is rotatably mounted in the housing and coaxially connected to the output gear. The drive nut is coaxially connected to the drive shaft.

[0015] The two drive mechanisms include a first drive mechanism and a second drive mechanism:

[0016] The difference between the total reduction ratio of the gear set of the first drive mechanism and the total reduction ratio of the gear set of the second drive mechanism is set; and / or,

[0017] The lead of the lead screw in the lead screw drive structure of the first drive mechanism is set differently from that in the lead screw drive structure of the second drive mechanism.

[0018] In one embodiment, the total reduction ratio of the gear set of the first drive mechanism is i1, and the total reduction ratio of the gear set of the second drive mechanism is i2, i1 / i2 = M;

[0019] The lead of the lead screw in the lead screw transmission structure of the first drive mechanism is L1, and the lead of the lead screw in the lead screw transmission structure of the second drive mechanism is L2, where L1 / L2 = N;

[0020] The output force of the drive shaft of the first drive mechanism is F1, and the output force of the drive shaft of the second drive mechanism is F2, F1 / F2=K;

[0021] Where K = M × (1 / N).

[0022] In one embodiment, the input gear has a first rotation axis extending along the first direction, and the output gear has a second rotation axis extending along the first direction.

[0023] The plurality of gears also includes a transmission gear, the third rotation axis of which extends along the first direction, the transmission gear including a first tooth portion and a second tooth portion coaxial and arranged in the direction of its rotation axis, the first tooth portion meshing with the input gear, and the second tooth portion meshing with the output gear;

[0024] The diameter of the input gear is D1, the diameter of the first tooth is D2, the diameter of the second tooth is D3, and the diameter of the output gear is D4, wherein D1 < D3 < D2 ≤ D4.

[0025] In one embodiment, the rotary motors of the two drive mechanisms are arranged side by side in a second direction, and the drive shafts of the two drive mechanisms are arranged side by side in a third direction.

[0026] Wherein, the first direction, the second direction, and the third direction are all perpendicular to each other;

[0027] The second rotation axes of the two output gears are centrally symmetrical about the midpoint of the first rotation axes of the two input gears;

[0028] The third rotation axis of the two transmission gears is centrally symmetrical about the midpoint of the first rotation axis of the two input gears.

[0029] In one embodiment, the input gear, the output gear, the first tooth, or the second tooth is configured as spur teeth or helical teeth.

[0030] In one embodiment, the linear actuator further includes a guide support structure through which the drive shaft is slidably disposed on the housing to limit radial displacement of the drive shaft.

[0031] In one embodiment, the guide support structure includes:

[0032] A guide portion, extending along the first direction, is fixedly installed within the housing; and,

[0033] A support portion is movably mounted on the guide portion along the first direction, and the support portion is fixedly connected to the drive shaft.

[0034] In one embodiment, the drive shaft has a guide hole extending along the first direction at one end located inside the housing;

[0035] One end of the lead screw is rotatably supported on the housing via a centripetal shaft, and the other end of the lead screw is sleeved in the guide hole and is movably arranged relative to the circumference of the drive shaft and the first direction.

[0036] In one embodiment, the guide support structure includes a linear guide pair, a splined bushing, or a sliding bearing.

[0037] In one embodiment, the lead screw is configured as a ball screw, a planetary roller screw, or a trapezoidal screw.

[0038] In one embodiment, the rotary motor includes a coreless motor, an axial flux motor, or a torque motor.

[0039] This utility model also proposes a bionic robotic hand, including a linear actuator, wherein the linear actuator comprises:

[0040] The housing has a first end located in a first direction; and,

[0041] Two drive mechanisms, each drive mechanism comprising:

[0042] A rotary motor is located inside the housing;

[0043] A drive shaft, extending along the first direction and movably and telescopically disposed at the first end of the housing along the first direction; and,

[0044] A transmission mechanism is provided, which drives the rotating shaft of the rotary motor to the drive shaft, and is used to convert the rotational motion of the rotating shaft of the rotary motor into the linear motion of the drive shaft.

[0045] The output force difference between the two drive shafts of the two drive mechanisms is set.

[0046] The technical solution provided by this utility model has at least the following advantages:

[0047] By integrating dual drive mechanisms into a single housing, the structure is made more compact and the system redundancy is reduced. At the same time, the differentiated output force design adapts to the torque requirements of cranks of different lengths, enhancing the adaptability and control precision of the drive system, so as to achieve high integration, high flexibility and high efficiency of the bionic manipulator. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0049] Figure 1 A schematic diagram of the structure of an embodiment of the linear actuator provided by this utility model;

[0050] Figure 2 for Figure 1 A cross-sectional schematic diagram of a linear actuator;

[0051] Figure 3 and Figure 4 for Figure 1 A partial structural diagram of a linear actuator;

[0052] Figure 5 for Figure 4 Exploded view of the two drive mechanisms and guide support structure in the middle;

[0053] Figure 6 for Figure 5 A bottom view of the drive mechanism.

[0054] Explanation of icon numbers:

[0055] 100. Linear actuator; 10. Housing; 20. Drive mechanism; 1. Rotary motor; 2. Drive shaft; 2a. Guide hole; 3. Transmission mechanism; 31. Gear set; 311. Input gear; 312. Output gear; 313. Transmission gear; 3131. First tooth; 3132. Second tooth; 32. Screw drive structure; 321. Screw; 322. Drive nut; 4. Guide support structure; 41. Guide part; 42. Support part; 5. Centripetal shaft.

[0056] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0057] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0058] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0059] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0060] In existing technologies, it is difficult to achieve both a compact structure and the independence and differentiated torque output capabilities of multiple outputs. Therefore, there is an urgent need for a multi-path linear drive mechanism with high integration, compact layout, and adaptability to different load requirements to solve the technical challenges of large drive unit size and poor adaptability in multi-degree-of-freedom systems.

[0061] This invention proposes a linear actuator to solve the problems of large size and poor adaptability of drive units in multi-degree-of-freedom systems.

[0062] Please see Figures 1 to 3 In one embodiment of this utility model, the linear actuator 100 is suitable for the multi-degree-of-freedom driving requirements of a bionic robotic hand. The linear actuator 100 includes a housing 10 and two drive mechanisms 20. The housing 10 has a first end located in a first direction. Each drive mechanism 20 includes a rotary motor 1, a drive shaft 2, and a transmission mechanism 3 that drives the rotating shaft of the rotary motor 1 and the drive shaft 2. The drive shaft 2 extends along the first direction and is telescopically movably disposed at the first end of the housing 10 along the first direction. The transmission mechanism 3 is used to convert the rotational motion of the rotating shaft of the rotary motor 1 into the linear motion of the drive shaft 2. The output force of the two drive shafts 2 of the two drive mechanisms 20 is set differently.

[0063] Specifically, the linear actuator 100 includes a housing 10 and two drive mechanisms 20 disposed within the housing 10. The housing 10 has one end in a first direction, which corresponds to the palm-length direction of the bionic hand, i.e., the longitudinal extension direction from the base of the palm to the fingertips. The two drive mechanisms 20 are integrated into the first end of the housing 10, sharing the outer shell structure, achieving a highly integrated design to reduce the overall volume and improve space utilization and structural compactness.

[0064] Each drive mechanism 20 includes a rotary motor 1, a drive shaft 2, and a transmission mechanism 3. The transmission mechanism 3 converts the rotational motion output by the rotary motor 1 into linear reciprocating motion of the drive shaft 2 along a first direction. The drive shaft 2 extends along the first direction and is telescopically mounted on the housing 10, enabling precise stroke and output control under external control signals. The drive shafts 2 of the two drive mechanisms 20 extend from the same side of the first end of the housing 10, facilitating centralized connection with the base crank of the bionic finger and optimizing the transmission path layout.

[0065] To meet the driving torque requirements of different degrees of freedom in the bionic robotic hand, the output force of the drive shaft 2 of the two drive mechanisms 20 is set differently.

[0066] In practical applications, each drive shaft 2 is connected to the corresponding first crank and second crank via a hinge to achieve flexion and extension movements of the finger joints. Due to structural space limitations, the lengths of the two cranks are often inconsistent. According to the torque balance principle, the output torque is equal to the product of the driving force and the lever arm length (T = F × L). When the crank lengths are unequal, the driving force needs to be designed differently to obtain the same joint output torque.

[0067] Specifically, the drive shaft 2 connected to the shorter crank needs to provide greater output force to compensate for its smaller lever arm, thereby ensuring that it matches the torque output of the longer crank end and achieving consistency and coordination of motion performance. Therefore, by configuring drive mechanisms 20 with different rated thrusts or adjusted by different transmission ratios, the output forces of the two drive shafts 2 can be differentiated, effectively meeting the differentiated requirements of different degrees of freedom for driving torque.

[0068] The linear actuator 100 improves structural compactness and reduces system redundancy by integrating dual drive mechanisms 20 into a single housing 10. At the same time, through differentiated output force design, it adapts to the torque requirements of cranks of different lengths, enhancing the adaptability and control precision of the drive system, so as to achieve high integration, high flexibility and high efficiency drive of the bionic manipulator.

[0069] Specifically, please refer to Figure 2 and Figure 4 In this embodiment, each of the transmission mechanisms 3 includes a gear set 31 and a lead screw transmission structure 32. The gear set 31 includes multiple gears that are connected in transmission, and the multiple gears include at least an input gear 311 and an output gear 312. The input gear 311 is coaxially connected to the rotating shaft of the rotary motor 1. The lead screw transmission structure 32 includes a lead screw 321 and a drive nut 322. The lead screw 321 is rotatably mounted in the housing 10 and coaxially connected to the output gear 312. The drive nut 322 is coaxially connected to the drive shaft 2. The two drive mechanisms 20 include a first drive mechanism 20 and a second drive mechanism 20: the total reduction ratio of the gear set 31 of the first drive mechanism 20 is different from the total reduction ratio of the gear set 31 of the second drive mechanism 20; and / or, the lead of the lead screw 321 of the lead screw transmission structure 32 of the first drive mechanism 20 is different from the lead of the lead screw 321 of the lead screw transmission structure 32 of the second drive mechanism 20.

[0070] In other words, the transmission mechanism 3 includes a gear set 31 and a lead screw transmission structure 32, forming a two-stage transmission system. The gear set 31 includes multiple gears connected in transmission, including at least an input gear 311 and an output gear 312. The input gear 311 is coaxially connected to the shaft of the rotary motor 1 and is used to receive initial power; the output gear 312 is used to output the decelerated rotational torque. The multiple gears also include a transmission gear 313, which has a first tooth portion 3131 and a second tooth portion 3132 coaxially arranged in the direction of its rotation axis, forming a double gear structure. The first tooth portion 3131 meshes with the input gear 311, and the second tooth portion 3132 meshes with the output gear 312, realizing two-stage reduction transmission. The first rotation axis of the input gear 311, the second rotation axis of the output gear 312, and the third rotation axis of the transmission gear 313 all extend along the first direction, forming a coplanar orthogonal layout.

[0071] The input gear 311 has a diameter of D1, the first tooth 3131 has a diameter of D2, the second tooth 3132 has a diameter of D3, and the output gear 312 has a diameter of D4, satisfying D1 < D3 < D2 ≤ D4. This dimensional relationship ensures a reasonable distribution of the transmission ratio, achieving effective speed reduction and torque increase, while avoiding gear interference and improving load-bearing capacity and transmission efficiency. The gears can be spur or helical. Spur gears are suitable for scenarios sensitive to axial dimensions and cost; helical gears offer advantages such as smooth transmission, low noise, and high load-bearing capacity, making them suitable for high-dynamic or high-precision applications. The specific form can be selected according to actual needs; this specification does not limit the specific form used in the embodiments.

[0072] The lead screw drive structure 32 includes a lead screw 321 and a drive nut 322. The lead screw 321 is rotatably mounted inside the housing 10 and coaxially connected to the output gear 312; the drive nut 322 is coaxially connected to the drive shaft 2. When the lead screw 321 rotates, it drives the drive nut 322 and the drive shaft 2 to move linearly in a first direction through helical side effect.

[0073] The difference in output force of the drive shafts 2 of the two drive mechanisms 20 is achieved by adjusting the total reduction ratio of the gear set 31 and / or the lead of the lead screw 321. By setting the total reduction ratio of the gear set 31 and / or the lead of the lead screw 321 differently in the two drive mechanisms 20, the output force characteristics of each drive shaft 2 can be flexibly adjusted in the integrated structure without the need for additional external force amplification mechanisms. This adapts to the differences in torque requirements caused by different crank lengths, improves the integration, energy efficiency, and control accuracy of the drive system, and meets the complex application requirements of bionic robotic arms for multi-degree-of-freedom differentiated drive force output.

[0074] Specifically, let the total reduction ratios of the gear sets 31 of the first drive mechanism 20 and the second drive mechanism 20 be i1 and i2, respectively, with a ratio M = i1 / i2; the leads of the lead screws 321 be L1 and L2, respectively, with a ratio N = L1 / L2; and the output forces of the drive shafts 2 be F1 and F2, respectively, with a ratio K = F1 / F2. According to the mechanical conversion relationship, under the same motor input torque condition, the linear output force is directly proportional to the reduction ratio and inversely proportional to the lead. According to the mechanical relationship, the linear output force F satisfies the following condition with respect to the input torque T and the lead L: F∝T / L. Therefore, under the same torque, the smaller the lead, the greater the output force, and the two are inversely proportional.

[0075] The final output force of drive shaft 2 is determined by both the reduction ratio and the lead. Let the motor output torque be T0, then the torque at the end of the lead screw 321 after reduction is: T0×i1 for the first drive mechanism 20 and T0×i2 for the second drive mechanism 20. The corresponding linear output forces are F1∝(T0×i1) / L1 and F2∝(T0×i2) / L2. The ratio of their output forces is K=F1 / F2=(i1 / i2)×(L2 / L1). Substituting M=i1 / i2 and N=L1 / L2, we get L2 / L1=1 / N, therefore K=M×(1 / N). This quantitative relationship provides a design basis for achieving precise output matching. By adjusting the combination of M and N, the two drive shafts 2 can output the required proportional linear force under different load conditions.

[0076] For example, when M=2 and N=0.5, K=4, meaning the output force of the first drive shaft 2 is four times that of the second drive shaft 2. This quantitative relationship provides a design basis for achieving precise output matching. By adjusting the combination of M and N, the two drive shafts 2 can be adapted to torque requirements under different crank lengths or load conditions.

[0077] By establishing a quantitative relationship between reduction ratio, lead and output force, the predictable and controllable design of multi-path drive output force is realized, thereby improving the adaptability of the linear actuator 100 to multi-degree-of-freedom differentiated loads in the bionic manipulator.

[0078] Specifically, please refer to Figure 2 and Figure 6 In this embodiment, the rotary motors 1 of the two drive mechanisms 20 are arranged side by side in the second direction, and the drive shafts 2 of the two drive mechanisms 20 are arranged side by side in the third direction; wherein, the first direction, the second direction, and the third direction are mutually perpendicular; the second rotation axes of the two output gears 312 are centrally symmetrical about the midpoint of the first rotation axes of the two input gears 311; the third rotation axes of the two transmission gears 313 are centrally symmetrical about the midpoint of the first rotation axes of the two input gears 311.

[0079] The rotary motors 1 of the two drive mechanisms 20 are arranged side by side in the second direction, and the drive shafts 2 are arranged side by side in the third direction. The first direction (the direction of movement of the drive shafts 2), the second direction (the direction of motor arrangement), and the third direction (the direction of arrangement of the drive shafts 2) are mutually perpendicular, forming a three-dimensional orthogonal layout. This structure makes full use of the internal space of the housing 10 and reduces the overall envelope size. The second rotation axis of the two output gears 312 and the third rotation axis of the two transmission gears 313 are all centrally symmetrical about the midpoint of the first rotation axis of the two input gears 311, realizing a completely mirror-symmetrical layout of the dual transmission chains. This symmetrical design ensures balanced power transmission path and symmetrical force, avoiding vibration and wear caused by off-center load. At the same time, the shared housing 10 and the absence of cross interference facilitate modular assembly and mass production.

[0080] Furthermore, to improve the motion stability of drive shaft 2 under asymmetrical loads, please refer to [link / reference needed]. Figures 2 to 5 The linear actuator 100 also includes a guide support structure 4, through which the drive shaft 2 is slidably disposed on the housing 10 to limit the radial displacement of the drive shaft 2.

[0081] In bionic robotic arm applications, the output end of drive shaft 2 is typically connected to a crank mechanism via a connecting rod or hinge. The direction of its force often deviates from the centerline of drive shaft 2, creating an eccentric load. This eccentric force generates a bending moment at drive nut 322, which is then transmitted to the internal transmission system via lead screw 321, forming an overturning moment. Without effective restraint, this moment will cause lead screw 321 to flex, bearing to become unbalanced, and localized stress concentration in the threaded joint, potentially leading to failures such as jamming, accelerated wear, or motion instability.

[0082] The guide support structure 4 is used to limit the displacement of the drive shaft 2 in the radial plane, so that the movement path of the drive shaft 2 is strictly constrained in the first direction. The guide support structure 4 is composed of a guide part 41 and a support part 42. The guide part 41 extends along the first direction and is fixedly installed in the housing 10, and can be a guide rail, a guide shaft, or a bushing structure; the support part 42 is slidably installed on the guide part 41 and fixedly connected to the drive shaft 2 to realize the linear reciprocating motion of the drive shaft 2 along the first direction.

[0083] The guide support structure 4 can be in the form of a ball linear guide pair, roller guide, spline bushing, or sliding bearing. The specific selection is determined according to the load size, movement speed, and accuracy requirements. This specification does not limit the specific type of guide support structure 4; it can be a circulating guide, a crossed roller guide, or a self-lubricating bushing structure. The specific configuration can be based on the spatial layout and working conditions. The embodiments in this specification do not limit this.

[0084] Specifically, please refer to Figure 2In this embodiment, the drive shaft 2 is provided with a guide hole 2a extending in the first direction at one end inside the housing 10. The guide hole 2a is a through hole or a blind hole structure, and the inner wall may be provided with a wear-resistant coating or an embedded bushing to reduce friction.

[0085] One end of the lead screw 321 is rotatably supported on the housing 10 by the radial shaft 5 bearing, forming a fixed fulcrum; the other end of the lead screw 321 extends into the guide hole 2a, and maintains a movable fit with the guide hole 2a in both the circumferential and first directions.

[0086] Specifically, the inner diameter of the guide hole 2a is larger than the outer diameter of the lead screw 321, with a radial clearance between them to allow the end of the lead screw 321 to float slightly in the radial direction. Simultaneously, the end of the lead screw 321 does not contact the bottom of the guide hole 2a axially, or only through a spherical / universal structure, to allow for angular deflection. This connection method creates a "floating hinge" relationship between the lead screw 321 and the drive shaft 2 to absorb alignment errors caused by deformation of the housing 10, bearing misalignment, or thermal expansion.

[0087] By setting a guide support structure 4 between the drive shaft 2 and the housing 10, and movably embedding the end of the lead screw 321 into the guide hole 2a of the drive shaft 2, the linear motion of the drive shaft 2 is constrained by an independent guiding system, while the lead screw 321 only undertakes torque transmission and axial thrust output. This decouples the power transmission path from the guiding load-bearing path, ensuring that the motion stability of the drive shaft 2 is not affected by fluctuations in the coaxiality of the lead screw 321's rotation. Simultaneously, the floating connection at the end of the lead screw 321 serves as an error compensation mechanism, adapting to assembly deviations and dynamic deformation, thereby reducing additional stress and frictional resistance during motion.

[0088] By setting a guide support structure 4 to independently guide the drive shaft 2, and by supporting one end of the lead screw 321 with a bearing and movably fitting the other end into the guide hole 2a of the drive shaft 2, combined with the independent guide support structure 4, the lead screw 321 can only transmit power and not participate in guidance, thereby avoiding it from bearing overturning torque and reducing the risk of wear and jamming.

[0089] To address the varying requirements of the linear actuator 100 under different operating conditions regarding guiding accuracy, load-bearing capacity, friction characteristics, and transmission efficiency, while also considering structural adaptability and manufacturing costs, multiple optional guide support structures 4 and lead screw 321 types are required. The guide support structure 4 provides independent linear guidance for the drive shaft 2 or drive nut 322 and constrains its radial displacement. Its specific implementation may include linear guide pairs, splined bushings, or sliding bearings.

[0090] The linear guide pair uses rolling elements that circulate between the guide rail and the slider to achieve low-friction guidance. The rolling elements can be steel balls or rollers, and the preload structure is adjustable to meet different stiffness requirements.

[0091] The spline bushing structure consists of an external gear shaft and an internal gear sleeve. It transmits torque through multi-tooth meshing while allowing axial sliding, making it suitable for applications that require both rotational floating and linear guidance.

[0092] Sliding bearings utilize the sliding friction between the bushing and the journal to achieve guidance. The materials can be copper-based alloys, polymer composites, or oil-impregnated powder metallurgy products, and they are characterized by compact structure and strong impact resistance.

[0093] This specification does not limit the specific form of the guide support structure 4. It can be a four-point contact guide rail, a crossed roller guide rail, a linear bearing unit, or a bushing guide structure. The specific form can be determined according to space constraints, load spectrum, speed requirements, and environmental conditions. The embodiments in this specification do not limit this.

[0094] Specifically, in this embodiment, the lead screw 321 serves as the core transmission element that converts rotary motion into linear motion, and its type can be set as a ball screw, planetary roller screw, or trapezoidal screw.

[0095] Ball screws transmit motion through steel balls that circulate between the screw's 321 thread raceway and the nut. They have a low coefficient of friction, high transmission efficiency, and are suitable for high-speed and high-precision applications.

[0096] Planetary roller screws employ multiple rollers arranged in a planetary pattern around the screw axis 321, transmitting power through threaded engagement. They feature higher contact stiffness and load-bearing density, making them suitable for heavy-duty, high-dynamic-response applications.

[0097] Trapezoidal lead screws rely on sliding friction between the threaded surfaces for transmission. They have a simple structure and self-locking capability, preventing reverse movement in the event of power failure or overload. They are suitable for applications where efficiency requirements are not high but reliable self-locking is necessary.

[0098] It should be noted that the lead, nominal diameter, accuracy class, and surface treatment of the lead screw 321 can be adapted to the design based on load characteristics, life requirements, and working environment. This manual does not limit the specific parameters and manufacturing process of the lead screw 321. It can be a single-start or multi-start thread, left-hand or right-hand thread, and the outer diameter can be stepped or constant. The specific design can be matched according to the output force, speed, and installation space. The embodiments in this manual do not limit this.

[0099] Specifically, the rotary motor 1 can be a high-response, high-power-density type such as a coreless motor, an axial flux motor, or a torque motor, suitable for miniaturized, high-dynamic-response biomimetic drive scenarios. Coreless motors have low inertia and fast response characteristics; axial flux motors have a flat structure and high power density; torque motors can achieve direct drive, simplifying the transmission chain. The type of motor can be flexibly selected according to specific performance requirements, and the embodiments in this specification do not limit this selection.

[0100] In summary, this linear actuator 100 achieves a highly compact structure and mechanical balance by integrating dual drive mechanisms 20 into a single housing 10 and employing an orthogonal layout and a centrally symmetrical transmission chain design. Differentiated reduction ratios and leads meet the diverse output requirements of multiple degrees of freedom. The guide support structure 4 effectively resists radial loads and overturning moments. Furthermore, the linear actuator 100 exhibits high spatial integration, enabling high integration, high flexibility, and high-efficiency drive output when applied to bionic robotic arms.

[0101] This utility model also proposes a bionic robotic hand, which includes fingers and a linear actuator 100. The specific structure of the linear actuator 100 is as described in the above embodiments. Since this bionic robotic hand adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0102] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A linear actuator (100) for a bionic robotic arm, characterized in that, The linear actuator (100) includes: The housing (10) has a first end in a first direction; and, Two drive mechanisms (20), each drive mechanism (20) comprising: A rotary motor (1) is disposed inside the housing (10); A drive shaft (2) extends along the first direction and is telescopically movably disposed at the first end of the housing (10) along the first direction; and, The transmission mechanism (3) is used to drive the rotating shaft of the rotary motor (1) and the drive shaft (2) to convert the rotational motion of the rotating shaft of the rotary motor (1) into the linear motion of the drive shaft (2). The output force of the two drive shafts (2) of the two drive mechanisms (20) is set to be different.

2. The linear actuator (100) as claimed in claim 1, characterized in that, Each of the aforementioned transmission mechanisms (3) includes: A gear set (31) includes a plurality of gears that are connected in a transmission manner, the plurality of gears including at least an input gear (311) and an output gear (312), the input gear (311) being coaxially connected to the shaft of the rotary motor (1); and, The lead screw drive structure (32) includes a lead screw (321) and a drive nut (322). The lead screw (321) is rotatably installed in the housing (10) and coaxially connected to the output gear (312). The drive nut (322) is coaxially connected to the drive shaft (2). The two drive mechanisms (20) include a first drive mechanism (20) and a second drive mechanism (20): The total reduction ratio of the gear set (31) of the first drive mechanism (20) is set differently from the total reduction ratio of the gear set (31) of the second drive mechanism (20); and / or, The lead of the lead screw (321) of the lead screw transmission structure (32) of the first drive mechanism (20) is set differently from that of the lead screw (321) of the lead screw transmission structure (32) of the second drive mechanism (20).

3. The linear actuator (100) as described in claim 2, characterized in that, The total reduction ratio of the gear set (31) of the first drive mechanism (20) is i1, and the total reduction ratio of the gear set (31) of the second drive mechanism (20) is i2, i1 / i2=M; The lead of the lead screw (321) of the lead screw transmission structure (32) of the first drive mechanism (20) is L1, and the lead of the lead screw (321) of the lead screw transmission structure (32) of the second drive mechanism (20) is L2, L1 / L2=N; The output force of the drive shaft (2) of the first drive mechanism (20) is F1, and the output force of the drive shaft (2) of the second drive mechanism (20) is F2, F1 / F2=K; Where K = M × (1 / N).

4. The linear actuator (100) as described in claim 2, characterized in that, The input gear (311) has a first rotation axis that extends along the first direction, and the output gear (312) has a second rotation axis that extends along the first direction. The plurality of gears further includes a transmission gear (313), the third rotation axis of which extends along the first direction. The transmission gear (313) includes a first tooth (3131) and a second tooth (3132) that are coaxial and arranged in the direction of its rotation axis. The first tooth (3131) meshes with the input gear (311), and the second tooth (3132) meshes with the output gear (312). The diameter of the input gear (311) is D1, the diameter of the first tooth (3131) is D2, the diameter of the second tooth (3132) is D3, and the diameter of the output gear (312) is D4, wherein D1 < D3 < D2 ≤ D4.

5. The linear actuator (100) as claimed in claim 4, characterized in that, The rotary motors (1) of the two drive mechanisms (20) are arranged side by side in the second direction, and the drive shafts (2) of the two drive mechanisms (20) are arranged side by side in the third direction. Wherein, the first direction, the second direction, and the third direction are all perpendicular to each other; The second rotation axes of the two output gears (312) are centrally symmetrical about the midpoint of the first rotation axes of the two input gears (311); The third rotation axis of the two transmission gears (313) is centrally symmetrical about the midpoint of the first rotation axis of the two input gears (311).

6. The linear actuator (100) as claimed in claim 4, characterized in that, The input gear (311), the output gear (312), the first tooth (3131) or the second tooth (3132) are configured as straight teeth or helical teeth.

7. The linear actuator (100) as claimed in claim 2, characterized in that, The linear actuator (100) further includes a guide support structure (4), through which the drive shaft (2) is slidably disposed on the housing (10) to limit the radial displacement of the drive shaft (2).

8. The linear actuator (100) as claimed in claim 7, characterized in that, The guide support structure (4) includes: A guide portion (41) is provided extending along the first direction and is fixedly installed inside the housing (10); and, A support (42) is movably mounted on the guide (41) along the first direction, and the support (42) is fixedly connected to the drive shaft (2).

9. The linear actuator (100) as claimed in claim 7, characterized in that, The guide support structure (4) includes a linear guide pair, a splined bushing, or a sliding bearing.

10. The linear actuator (100) as claimed in claim 2, characterized in that, The drive shaft (2) has a guide hole (2a) extending along the first direction at one end inside the housing (10); One end of the lead screw (321) is rotatably supported on the housing (10) via a centripetal shaft (5), and the other end of the lead screw (321) is sleeved in the guide hole (2a) and is movably arranged relative to the circumference and the first direction of the drive shaft (2).

11. The linear actuator (100) as claimed in claim 2, characterized in that, The lead screw (321) is configured as a ball screw, a planetary roller screw, or a trapezoidal screw.

12. The linear actuator (100) as claimed in claim 1, characterized in that, The rotary motor (1) includes a coreless motor, an axial flux motor, or a torque motor.

13. A bionic robotic hand, characterized in that, Includes the linear actuator (100) as described in any one of claims 1 to 12.

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