High-precision automatic backlash reduction machine for robot dexterous hand and robot dexterous hand

Abstract

The application discloses a high-precision automatic clearance-eliminating speed reducer for a robot dexterous hand and the robot dexterous hand, and relates to the technical field of robot dexterous hands. The speed reducer comprises a shell, a worm wheel, a worm, a supporting bearing and an end cover, the worm wheel and the worm are rotatably arranged in the shell and are in engagement with each other, the supporting bearing is arranged in the shell and is used for supporting the worm wheel or the worm, and the end cover is fixed on the shell; the supporting bearing is located in the end cover, a notch is formed in the side wall of the end cover to form a cantilever type elastic arm, and the elastic arm is located on one side of the supporting bearing away from the engagement part; the supporting bearing and the end cover are arranged eccentrically during assembly, the elastic arm is in an elastic deformation state, and the elastic arm exerts an elastic force on the supporting bearing towards the engagement part. The application can improve transmission precision, control precision and running stability of the robot dexterous hand, and meets the high reliability requirement of the robot dexterous hand.

Description

Technical Field

[0001] This invention relates to the field of robot dexterity technology, and in particular to a high-precision automatic backlash elimination reducer for robot dexterity and a robot dexterity. Background Technology

[0002] In recent years, robotics technology has developed rapidly, and each joint of a robot requires a high-precision reducer to provide power. For the main joints of a robot, such as its limbs, harmonic reducers or planetary reducers are typically used, as the technology is relatively mature. However, for dexterous robotic hands, due to their extremely compact structure and the requirement for self-locking, the above-mentioned types of reducers are difficult to apply directly.

[0003] Currently, miniature speed reducers used in dexterous hands mainly face the following problems: 1. Large backlash Due to the extremely limited internal space of the dexterous hand, conventional backlash elimination structures (such as double gear offset backlash elimination, spring clamping, etc.) do not have sufficient installation space, resulting in a generally large backlash in the reducer. Excessive backlash can cause finger tremors during rapid start-stop or reversal, severely affecting the control accuracy and operational smoothness of the dexterous hand.

[0004] II. The gap is difficult to maintain for a long time. Existing micro reducers may achieve a small clearance during initial assembly through selection or adjustment. However, during long-term use, the clearance gradually increases due to slight wear on the worm gear teeth, and this clearance cannot be automatically compensated for. This increase in clearance not only reduces transmission accuracy but also shortens the effective service life of the reducer, making it difficult to meet the high reliability requirements of robotic dexterity hands. Summary of the Invention

[0005] The purpose of this invention is to provide a high-precision automatic backlash-eliminating reducer for robot dexterity hands and a robot dexterity hand, so as to solve the problems existing in the prior art, improve the transmission accuracy, control accuracy of the dexterity hand, operation stability and meet the high reliability requirements of robot dexterity hands.

[0006] To achieve the above objectives, the present invention provides the following solution: This invention provides a high-precision automatic backlash-eliminating reducer for a robot dexterous hand, comprising: a housing, a worm gear, a worm, a support bearing, and an end cap. The worm gear is rotatably disposed within the housing; the worm is rotatably disposed within the housing and meshes with the worm gear; the support bearing is disposed within the housing and provides rotational support for the end of the worm gear or the worm; the end cap is fixed to the housing; the support bearing is located inside the end cap, and a notch is provided on the side wall of the end cap, the notch forming a cantilevered elastic arm on a portion of the side wall of the end cap, the cantilevered elastic arm being located on the side of the support bearing radially away from the meshing portion of the worm gear and the worm; in the assembled state, the support bearing is eccentrically disposed with respect to the end cap, and the axis of the support bearing is offset from the axis of the end cap in a direction away from the meshing portion, the cantilevered elastic arm being in an elastic deformation state to provide the support bearing with an elastic force to move towards the meshing portion.

[0007] Preferably, the end cap has a first notch and a second notch, and the end cap has a structure with one open end and one closed end. The first notch extends axially from the edge of the open end of the end cap towards the closed end. The second notch is located at the end of the first notch and extends circumferentially along the end cap. The end of the first notch is connected to the middle of the second notch. The sidewall between the second notch and the open end of the end cap forms the cantilevered elastic arm.

[0008] Preferably, the center plane of the first notch is coplanar with the center line of the bearing and the center line of the worm gear, so that the cantilevered elastic arm in the elastic deformation state can give the support bearing an elastic force that moves radially toward the meshing part.

[0009] Preferably, the inner side of the cantilever elastic arm is provided with an arc-shaped groove to reduce the rigidity of the cantilever elastic arm.

[0010] Preferably, the surfaces of both the worm gear and the worm are hardened.

[0011] Preferably, the support bearing is disposed at one end of the worm wheel shaft of the worm wheel, and is used to provide rotational support for the worm wheel.

[0012] Preferably, the worm gear is installed in a worm gear cavity within the housing, with one end of the worm gear cavity being open to facilitate the installation of the worm gear inside the worm gear cavity, and the end cap is installed at the open end of the worm gear cavity to confine the worm gear inside the worm gear cavity.

[0013] Preferably, when the worm gear and the worm are engaged with zero clearance, the support bearing has the freedom to move radially toward the engagement portion within the end cover.

[0014] The present invention also provides a robot dexterous hand, including at least one high-precision automatic backlash elimination reducer for a robot dexterous hand as described above.

[0015] The present invention achieves the following technical effects compared to the prior art: In this invention, a cantilevered elastic arm is integrally molded onto the side wall of the end cap, and the support bearing is eccentrically positioned relative to the end cap. During assembly, the cantilevered elastic arm is forced to undergo elastic deformation, thereby applying a continuous radial elastic force to the support bearing. This elastic force is directed directly towards the meshing part of the worm gear and worm, ensuring that the worm gear is always pressed against the worm, thus eliminating radial meshing backlash. When the worm gear tooth surface experiences slight wear, the cantilevered elastic arm can automatically release more elastic force to compensate, achieving long-term automatic backlash elimination. This allows the reducer to maintain high transmission accuracy even after long-term use, extending its effective service life and meeting the high reliability requirements of robot dexterity hands. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of a robot dexterous hand provided in some embodiments of the present invention; Figure 2 for Figure 1 A sectional view; Figure 3 for Figure 2 FF section view; Figure 4 for Figure 2 NN-direction cross-sectional view; Figure 5 This is a schematic diagram of the end cap structure; Figure 6 This is a schematic diagram of the reducer structure after removing the housing in some embodiments; Figure 7 for Figure 6 Exploded view of the structure; In the diagram: 1-Housing; 2-Worm wheel; 3-Worm; 4-Support bearing; 5-Cantilever elastic arm; 6-Meshing part; 7-Worm wheel shaft; 8-End cover; 9-First gap; 10-Second gap; 11-First notch; 12-Second notch; 13-Arc groove; 100-Finger joint. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The purpose of this invention is to provide a high-precision automatic backlash-eliminating reducer for robot dexterity hands and a robot dexterity hand, so as to solve the problems existing in the prior art, improve the transmission accuracy, control accuracy of the dexterity hand, operation stability and meet the high reliability requirements of robot dexterity hands.

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] The following is combined with Figures 1 to 7 The following describes embodiments of the present invention.

[0022] Example 1 This invention provides a high-precision automatic backlash elimination reducer for robot dexterity hands, such as... Figures 5-7 As shown, the assembly includes: a housing 1, a worm gear 2, a worm 3, a support bearing 4, and an end cover 8. The worm gear 2 is rotatably disposed within the housing 1; the worm 3 is rotatably disposed within the housing 1 and meshes with the worm gear 2; the support bearing 4 is disposed within the housing 1 and provides rotational support for the end of the worm gear 2 or the worm 3; the end cover 8 is fixed to the housing 1; the support bearing 4 is located inside the end cover 8, and a notch is provided on the side wall of the end cover 8, which forms a cantilevered elastic arm 5 on a portion of the side wall of the end cover 8. The cantilevered elastic arm 5 is located on the side of the support bearing 4 that is radially away from the meshing part 6 of the worm gear 2 and the worm 3; in the assembled state, the support bearing 4 is eccentrically disposed with the end cover 8, and the axis of the support bearing 4 is offset from the axis of the end cover 8 in a direction away from the meshing part 6. The cantilevered elastic arm 5 is in an elastic deformation state to provide the support bearing 4 with an elastic force to move towards the meshing part 6.

[0023] In this embodiment, the cantilevered elastic arm 5 is integrally formed on the side wall of the end cover 8, and the support bearing 4 is eccentrically positioned relative to the end cover 8, such as... Figure 4 During assembly, the cantilevered elastic arm 5 is forced to undergo elastic deformation, thereby applying a continuous radial elastic force to the support bearing 4. Figure 4This is a schematic diagram of the assembled state, showing a first gap 9 and a second gap 10. The elastic force is directed directly towards the meshing part 6 of the worm wheel 2 and the worm 3, ensuring that the worm wheel 2 is always pressed against the worm 3, thereby eliminating radial meshing clearance. When the tooth surface of the worm wheel 2 experiences slight wear, the cantilevered elastic arm 5 can automatically release more elastic force for compensation, achieving long-term automatic clearance elimination. This ensures that the reducer still maintains high transmission accuracy after long-term use, extending the effective service life of the reducer and meeting the high reliability requirements of the robot's dexterous hand.

[0024] In some embodiments, the end cap 8 is provided with a first notch 11 and a second notch 12. The end cap 8 has a structure with one end open and the other end closed. The first notch 11 extends axially from the edge of the open end of the end cap 8 toward the closed end. The second notch 12 is provided at the end of the first notch 11 and extends circumferentially along the end cap 8. The end of the first notch 11 is connected to the middle of the second notch 12. The sidewall between the second notch 12 and the open end of the end cap 8 forms a cantilevered elastic arm 5.

[0025] This embodiment specifically defines the shape of the notch. The first notch 11 extends axially, and the second notch 12 extends circumferentially and connects to the end of the first notch 11. Together, they form a "T-shaped" cutting path. This creates two independent cantilevered elastic arms 5, thereby doubling the clamping effect. In addition, their symmetrical arrangement allows the support bearing 4 to have better centering performance.

[0026] In this embodiment, the notch is T-shaped, but in other embodiments, the notch can also be arc-shaped, wavy, or other non-linear shapes, as long as it can form a cantilevered elastic arm 5 on the wall of the end cap 8. The number of notches is not limited to two; it can be one, three, or more. Multiple notches can form multiple elastic arms, which work together to support the bearing 4, making the force more even. In addition, the dimensions (width, depth, and length) of the notch can be optimized according to the required elastic force and the material of the end cap 8.

[0027] In some embodiments, the thickness of the end cap 8 wall is 1mm to 10mm; for example, it can be 1mm, 2mm, 3mm, 4mm, 5mm, etc.

[0028] In some embodiments, the center plane of the first notch 11 is coplanar with the center line of the bearing and the center line of the worm gear 2 so that the cantilevered elastic arm 5 in an elastic deformation state can provide the supporting bearing 4 with an elastic force that moves radially toward the meshing part 6.

[0029] This embodiment defines the spatial position of the first notch 11, ensuring that its center plane is coplanar with the centerline of the support bearing 4 and the centerline of the worm gear 2. This coplanar design ensures that the direction of the elastic force generated by the cantilevered elastic arm 5 coincides with the centerline of the worm gear 2, meaning that most of the elastic force points radially towards the worm 3, reducing force components in other directions. When the direction of the elastic force is completely consistent with the direction of movement of the worm gear 2, the force utilization efficiency is highest, preventing unnecessary torque or off-center load on the worm gear shaft 7 due to oblique force components, thereby avoiding additional bearing wear and reduced transmission efficiency. This precise force direction control is a key guarantee for high-precision transmission.

[0030] In this embodiment, the center plane of the notch is coplanar with the center line of the bearing and the center line of the worm gear 2. However, in other embodiments, there may be a slight angle between the center plane of the notch and the center line of the bearing, as long as the radial component of the elastic force is sufficient to eliminate the meshing clearance. In some application scenarios, the direction of the elastic force may be intentionally made to form a slight angle with the radial direction to simultaneously generate an axial preload effect and further eliminate axial movement.

[0031] In some embodiments, an arc-shaped groove 13 is provided on the inner side of the cantilever elastic arm 5 to reduce the rigidity of the cantilever elastic arm 5.

[0032] In this embodiment, an arc-shaped groove 13 is formed on the inner side of the cantilever elastic arm 5, which is equivalent to setting a stress concentration area or thinning area on the elastic arm. The presence of the arc-shaped groove 13 reduces the section modulus of the elastic arm, thereby reducing its bending stiffness. Under the same preload deformation, the elastic arm with lower stiffness generates less elastic force, but the rate of change of elastic force with deformation is also smaller, that is, the elastic force versus deformation curve is smoother. This characteristic makes the elastic arm more tolerant to assembly errors and wear: even if the deformation changes due to manufacturing tolerances or long-term wear, the fluctuation of elastic force is smaller, thus making the backlash elimination effect more stable. In addition, the arc-shaped groove 13 structure can also avoid stress concentration and improve the fatigue life of the elastic arm.

[0033] The number of arc-shaped grooves 13 can be one or more, and the setting position can be the inner side, outer side or both sides of the elastic arm.

[0034] In some embodiments, the surfaces of both the worm gear 2 and the worm 3 are hardened.

[0035] In this embodiment, the surfaces of the worm gear 2 and worm 3 are hardened, for example, by carburizing and quenching, nitriding, or induction hardening. This hardening treatment forms a high-hardness, wear-resistant layer on the tooth surface, significantly improving its wear resistance. Because the cantilevered elastic arm 5 continuously applies elastic force, keeping the worm gear 2 constantly pressed against the worm 3, the contact stress on the tooth surface is high. Without hardening treatment, premature wear would easily occur, leading to the reappearance of backlash. After hardening treatment, the wear resistance of the tooth surface is greatly improved. Combined with the automatic compensation function of the elastic arm, it can maintain a zero or micro-backlash state for a longer service life, significantly extending the effective working life of the reducer.

[0036] In this embodiment, surface hardening treatment is used. However, in other embodiments, other surface strengthening processes such as integral quenching, nitriding, hard chrome plating, and spraying wear-resistant coatings can also be used. For light-load applications, hardening treatment may not be necessary; wear resistance can be ensured simply by selecting high-strength materials (such as alloy steel or powder metallurgy materials). The hardening treatment methods for the worm gear 2 and worm 3 can be the same, or different treatment processes can be used according to their respective stress characteristics.

[0037] In some embodiments, a support bearing 4 is disposed at one end of the worm shaft 7 of the worm gear 2 to provide rotational support for the worm gear 2.

[0038] In this embodiment, the support bearing 4 is explicitly positioned at one end of the worm wheel shaft 7 of the worm wheel 2, meaning the elastic element acts directly on the support bearing 4 on the side of the worm wheel 2. However, in other embodiments, the support bearing 4 can also be positioned at the end of the worm 3, meaning the elastic element acts on the bearing on the side of the worm 3. In this case, the elastic force direction of the cantilevered elastic arm 5 needs to be adjusted accordingly to point towards the worm wheel 2, which can also achieve the purpose of eliminating radial clearance. This alternative solution is suitable for layout scenarios where there is more space on the side of the worm 3.

[0039] In some embodiments, the worm gear 2 is installed in the worm gear 2 cavity inside the housing 1, and one end of the worm gear 2 cavity is open to facilitate the installation of the worm gear 2 inside the worm gear 2 cavity. The end cap 8 is installed at the open end of the worm gear 2 cavity to confine the worm gear 2 inside the worm gear 2 cavity.

[0040] This embodiment describes the structure of the housing 1. The worm gear 2 cavity is a structure in the prior art, which usually has an open end to facilitate the installation of the worm gear 2, and the other end usually has a through hole to facilitate connection with other joints.

[0041] In this embodiment, the end cap 8 serves both as a sealed cavity and as a carrier for the cantilevered elastic arm 5, while also confining the worm gear shaft 7 within the cavity. This "one cap, multiple uses" design greatly simplifies the assembly process: during assembly, simply push the worm gear 2 assembly into the worm gear 2 cavity, then press the end cap 8 in and fix it. During the fixing process, the end cap 8 automatically completes the pre-compression and eccentric positioning of the elastic arm. Compared to traditional backlash-eliminating structures that require multiple independent parts (such as springs, retaining rings, washers, etc.), this embodiment significantly reduces the number of parts and assembly steps, thereby lowering manufacturing costs.

[0042] In some embodiments, when the worm gear 2 and worm 3 are engaged with zero clearance, the support bearing 4 has the freedom to move radially toward the engagement portion 6 within the end cover 8.

[0043] This embodiment limits the degree of freedom of movement of the support bearing 4 within the end cover 8. Specifically, even in a zero-backlash engagement state, the support bearing 4 still has a small margin for radial movement towards the engagement part 6. This design ensures that the support bearing 4 possesses a degree of freedom of movement. When minor wear occurs on the tooth surface, the support bearing 4 can utilize this degree of freedom to continue moving towards the engagement part 6, and the cantilevered elastic arm 5 releases more elastic force, maintaining close contact between the worm gear 2 and the worm 3. If the support bearing 4 is completely locked, the wear clearance cannot be automatically compensated, and the elastic force of the elastic arm will lose its effect. Therefore, the existence of this degree of freedom is the structural basis for realizing the "automatic backlash elimination" function.

[0044] Example 2 The present invention also provides a robot dexterous hand, including at least one high-precision automatic backlash elimination reducer for the robot dexterous hand as described in Embodiment 1.

[0045] This embodiment applies the aforementioned reducer to a robotic dexterous hand, which typically consists of multiple finger joints 100, each of which can be equipped with one reducer of this invention. Due to its compact structure, high precision, automatic backlash elimination, and long-term stability, this reducer enables each finger joint 100 of the dexterous hand to achieve zero backlash or micro-arc graded transmission, significantly improving the overall control precision and operational smoothness of the hand. The fingers do not experience vibration or positioning deviation during rapid start-stop, reversal, or grasping actions, allowing for more precise operational tasks (such as precision assembly, minimally invasive surgery, and flexible grasping). Furthermore, because the reducer has the ability to automatically compensate for wear, the dexterous hand does not require periodic adjustment or replacement of the reducer throughout its entire lifespan, reducing maintenance costs.

[0046] The high-precision automatic backlash elimination reducer for robot dexterous hands of the present invention has been successfully applied to the dexterous hand and has achieved the expected results. The backlash has been improved from the original 30 arc minutes to within 3 arc minutes and can be maintained within this range for a long time. For some models, it can achieve the requirement of maintaining 0 arc minutes backlash for a long time.

[0047] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A high-precision automatic backlash-eliminating reducer for a robot dexterous hand, comprising: The device comprises a housing, a worm gear, a worm, a support bearing, and an end cap. The worm gear is rotatably disposed within the housing. The worm is rotatably disposed within the housing and meshes with the worm gear. The support bearing is disposed within the housing and provides rotational support for the end of the worm gear or the worm. The end cap is fixed to the housing. The device is characterized in that the support bearing is located inside the end cap, and a notch is provided on the side wall of the end cap, forming a cantilevered elastic arm on a portion of the side wall. The cantilevered elastic arm is located on the side of the support bearing radially away from the meshing portion of the worm gear and the worm. In the assembled state, the support bearing is eccentrically disposed with respect to the end cap, and the axis of the support bearing is offset from the axis of the end cap in a direction away from the meshing portion. The cantilevered elastic arm is in an elastic deformation state to provide the support bearing with an elastic force that moves towards the meshing portion.

2. The high-precision automatic backlash-eliminating reducer for robot dexterous hands according to claim 1, characterized in that, The end cap has a first notch and a second notch. The end cap has a structure with one end open and one end closed. The first notch extends axially from the edge of the open end of the end cap towards the closed end. The second notch is located at the end of the first notch and extends circumferentially along the end cap. The end of the first notch is connected to the middle of the second notch. The sidewall between the second notch and the open end of the end cap forms the cantilevered elastic arm.

3. The high-precision automatic backlash-eliminating reducer for robot dexterous hands according to claim 2, characterized in that, The center plane of the first notch is coplanar with the center line of the bearing and the center line of the worm gear so that the cantilevered elastic arm in the elastic deformation state can give the support bearing an elastic force that moves radially toward the meshing part.

4. The high-precision automatic backlash-eliminating reducer for robot dexterous hands according to claim 1, characterized in that, The inner side of the cantilever elastic arm is provided with an arc-shaped groove to reduce the rigidity of the cantilever elastic arm.

5. The high-precision automatic backlash-eliminating reducer for robot dexterous hands according to claim 1, characterized in that, The surfaces of both the worm gear and the worm have been hardened.

6. The high-precision automatic backlash-eliminating reducer for robot dexterous hands according to claim 1, characterized in that, The support bearing is disposed at one end of the worm gear shaft of the worm gear and is used to provide rotational support for the worm gear.

7. The high-precision automatic backlash-eliminating reducer for robot dexterous hands according to claim 1, characterized in that, The worm gear is installed in the worm gear cavity within the housing. One end of the worm gear cavity is open to facilitate the installation of the worm gear inside the worm gear cavity. The end cap is installed at the open end of the worm gear cavity to confine the worm gear inside the worm gear cavity.

8. The high-precision automatic backlash-eliminating reducer for robot dexterous hands according to claim 1, characterized in that, When the worm gear and the worm are engaged with zero clearance, the support bearing has the freedom to move radially toward the engagement part within the end cover.

9. A robotic dexterous hand, characterized in that, It includes at least one high-precision automatic backlash-eliminating reducer for robot dexterity hands as described in any one of claims 1 to 8.

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