Mechanical arm joint structure and mechanical arm

Abstract

This invention provides a robotic arm joint structure and robotic arm, belonging to the field of robotic arm technology. The robotic arm joint structure includes a first connecting arm and a second connecting arm hinged together; it also includes a support portion, comprising a first connecting end and a second connecting end. The first connecting end is hinged to the arm body of the first connecting arm, and the second connecting end is slidably connected to the arm body of the second connecting arm. The arm body of the second connecting arm is provided with a driving portion, the driving end of which is kinetically connected to the support portion. The driving portion can drive the support portion to move along the arm body direction of the second connecting arm, so that the first connecting arm is driven by the support portion to rotate relative to the second connecting arm. The robotic arm joint structure and robotic arm provided by this invention can reduce the torque borne by the joint parts of the robotic arm, which is beneficial to improving the service life of the robotic arm.

Description

Technical Field

[0001] This invention relates to the field of robotic arm technology, and in particular to a robotic arm joint structure and a robotic arm. Background Technology

[0002] With the advancement and development of science and technology, robotic arms, due to their unique operational flexibility, have been widely used in various fields such as industrial manufacturing, medical treatment, national defense and military, entertainment services, and scientific research.

[0003] Current robotic arms are generally designed with multiple articulated joints to increase their degrees of freedom. Motors are usually directly installed at the joints, driving adjacent movable arms to rotate. However, the torque applied by the motors to the movable arms is large, requiring extremely high structural strength at the joints. When the robotic arm is gripping heavy objects or subjected to unexpected vertical impacts, the connection between the motors and the movable arms can easily be damaged, affecting the normal use of the robotic arm.

[0004] Therefore, it is urgent to solve the problem that the joints of existing robotic arms are subject to large torques and are prone to damage. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a robotic arm joint structure and robotic arm to solve the problem of large torque bearing in the joint parts of robotic arms in the prior art.

[0006] To achieve the above objectives, the present invention provides a robotic arm joint structure, comprising:

[0007] The first and second connecting arms are hinged together.

[0008] The support includes a first connecting end and a second connecting end, wherein the first connecting end is hinged to the arm body of the first connecting arm, and the second connecting end is slidably connected to the arm body of the second connecting arm;

[0009] The second connecting arm is provided with a driving part on its body. The driving end of the driving part is connected to the support part in a transmission manner. The driving part can drive the support part to move along the body direction of the second connecting arm, so that the first connecting arm is driven by the support part to rotate relative to the second connecting arm.

[0010] Furthermore, the second connecting arm is provided with a guide groove extending along its length direction, and the second connecting end of the support is constrained in the guide groove. The second connecting end is configured to move along the direction of the guide groove under the driving force of the driving part.

[0011] Furthermore, the second connecting end of the support is connected to a transmission rack, which is constrained in the guide groove. The driving end of the drive unit is connected to a transmission gear that moves synchronously with the driving end, and the transmission rack meshes with the transmission gear.

[0012] Furthermore, the second connecting arm has a hollow cavity inside its body, the guide groove is located in the cavity, and the cavity is provided with guide rods connecting the two ends of the second connecting arm. A guide ring is sleeved on the guide rod, and the guide ring is fixedly connected to the transmission rack.

[0013] Furthermore, the support includes at least two connecting rods, and adjacent connecting rods are rotatably connected by a damping shaft.

[0014] Furthermore, the support includes three connecting rods that are rotatably connected in sequence, with the length of the middle connecting rod being greater than the length of the connecting rods at both ends.

[0015] Furthermore, the drive unit is a DC servo motor capable of forward and reverse rotation.

[0016] Furthermore, it also includes:

[0017] A third connecting arm is used to support the second connecting arm and the first connecting arm, and the third connecting arm is hinged to the second connecting arm;

[0018] The diagonal brace has one end hinged to the second connecting arm and the other end slidably mounted on the body of the third connecting arm. An elastic element is connected between the sliding end of the diagonal brace and the third connecting arm, and the elastic element has an elastic force that drives the diagonal brace to move toward the second connecting arm.

[0019] Furthermore, the third connecting arm has a mounting groove, the sliding end is limited and constrained in the mounting groove, and the two ends of the elastic member are respectively connected to the bottom of the mounting groove and the sliding end.

[0020] In addition, this application also provides a robotic arm, including the robotic arm joint structure as described in any of the preceding claims.

[0021] As can be seen from the above, the robotic arm joint structure provided by the present invention has a support part between the first connecting arm and the second connecting arm. Since the driving part is located on the arm body of the second connecting arm, the hinge joint of the first connecting arm and the second connecting arm is not directly driven to rotate by force, which effectively reduces the torque borne by the joint and also avoids the problem that the driving part is easily damaged by external factors when it is located at the joint.

[0022] Furthermore, since the second connecting end of the support is slidably connected to the second connecting arm, when the first connecting arm rotates relative to the second connecting arm, the support will be connected between the first and second connecting arms in the form of a diagonal bracing angle. The support, the first connecting arm, and the second connecting arm together form a triangular stable structure, which effectively improves the working stability of the robotic arm, thereby improving the use effect of the robotic arm. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a perspective view of the robotic arm joint structure in an embodiment of the present invention;

[0025] Figure 2 This is a perspective view of the robotic arm joint structure from another angle in an embodiment of the present invention;

[0026] Figure 3 This is an exploded view of the second connecting arm in an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of the cooperation between the transmission rack and the drive unit in an embodiment of the present invention;

[0028] Figure 5 This is an exploded view of the robotic arm in an embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of the structure of the guide collar on the first connecting arm in an embodiment of the present invention.

[0030] Explanation of reference numerals in the attached figures

[0031] 1. First connecting arm; 11. External motor;

[0032] 2. Second connecting arm; 21. Drive unit; 22. Guide groove; 231. Transmission gear;

[0033] 3. Third connecting arm; 31. Mounting slot;

[0034] 41. Connecting rod; 42. Drive rack; 44. Reversing gear;

[0035] 51. Diagonal brace.

[0036] 6. Mechanical gripper; 7. Base. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0038] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this invention should have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms "first," "second," and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0039] Due to their unique operational flexibility, robotic arms have been widely used in various fields such as industrial manufacturing, medical treatment, national defense, entertainment services, and scientific research. Currently, multiple articulated robotic arm joint structures are generally designed to enhance the degree of freedom of the robotic arm. Motors are directly installed at the joints of the robotic arm, and each articulated robotic arm joint is driven by gears or other means of meshing transmission. The motor drives one of its gears to rotate, thereby driving the adjacent movable arm to perform rotational movements.

[0040] However, in the process of realizing this disclosure, the applicant discovered that the main problem with existing robotic arms is that the motor applies a large torque to the movable arm, which requires the joints of the robotic arm to have extremely high structural strength. When the robotic arm is gripping heavy objects or is subjected to an unexpected impact from an external force in the vertical direction, the connection between the motor and the movable arm is easily damaged, which affects the normal use of the robotic arm.

[0041] In view of this, one or more embodiments in this specification provide a robotic arm joint structure, such as... Figure 1 and Figure 2 As shown, the device includes a first connecting arm 1 and a second connecting arm 2 that are hinged together; it also includes a support portion, which includes a first connecting end and a second connecting end. The first connecting end is hinged to the arm body of the first connecting arm 1, and the second connecting end is slidably connected to the arm body of the second connecting arm 2. The arm body of the second connecting arm 2 is provided with a driving portion 21, the driving end of which is connected to the support portion. The driving portion 21 can drive the support portion to move along the arm body direction of the second connecting arm 2, so that the first connecting arm 1 is driven by the support portion to rotate relative to the second connecting arm 2.

[0042] As can be seen from the above description, the robotic arm joint structure provided in this embodiment has a support part between the first connecting arm 1 and the second connecting arm 2. Since the driving part 21 is located on the arm body of the second connecting arm 2, the hinge joint of the first connecting arm 1 and the second connecting arm 2 is not directly driven to rotate by force, which effectively reduces the torque borne by the joint and also avoids the problem that the driving part 21 is easily damaged by external factors when it is located at the joint.

[0043] Furthermore, since the second connecting end of the support is slidably connected to the second connecting arm 2, when the first connecting arm 1 rotates relative to the second connecting arm 2, the support will be connected between the first connecting arm 1 and the second connecting arm 2 in a structure with a certain angled bracket. The support, the first connecting arm 1 and the second connecting arm 2 together form a triangular stable structure, which effectively enhances the working stability of the robotic arm, thereby improving the use effect of the robotic arm.

[0044] In the above description, the first connecting arm 1 and the second connecting arm 2, which are hinged, are only used for illustrative purposes. The positions of the first connecting arm 1 and the second connecting arm 2 in the entire robotic arm system are not absolutely defined. Preferably, the second connecting arm 2 is positioned relatively below the first connecting arm 1 to support it. Positioning the second connecting arm 2 relatively below the first connecting arm 1 makes the support portion more stable in supporting the first connecting arm 1, which is beneficial for maintaining stable clamping of the robotic arm. Here, the directional terms such as "upper" and "lower" mentioned in this embodiment are used with reference to... Figure 1 The directions are explained in the text. Figure 1 In the middle, the second connecting arm 2 is located below the first connecting arm 1.

[0045] like Figures 1 to 3 As shown, in some embodiments, the second connecting arm 2 is provided with a guide groove 22 extending along its arm length direction, and the second connecting end of the support is limited and constrained in the guide groove 22. The second connecting end is configured to move along the direction of the guide groove 22 under the driving force of the driving part 21.

[0046] Specifically, in this embodiment, the second connecting arm 2 has a rectangular cross-section. A guide groove 22 is located inside the body of the second connecting arm 2. A transmission rack 42 is connected to the second connecting end of the support portion. The transmission rack 42 is constrained within the guide groove 22. A synchronously operating transmission gear 231 is connected to the driving end of the driving portion 21. The transmission rack 42 meshes with the transmission gear 231, thus forming a transmission connection between the driving portion 21 and the support portion. Preferably, the second connecting end is hinged to the transmission rack 42 to further enhance the flexibility of the support portion.

[0047] like Figure 4As shown, the transmission gear 231 and the transmission rack 42 are further connected by a reversing gear 44. The diameter of the reversing gear 44 is smaller than that of the transmission gear 231. This arrangement can increase the transmission ratio of the transmission gear 231, thereby effectively improving the driving force of the drive unit 21 on the transmission rack 42.

[0048] In the above embodiment, the transmission rack 42 is fitted into the guide rail of the guide groove 22 to achieve its limiting constraint in the guide groove 22; furthermore, a smooth guide surface can be provided at the bottom of the guide groove 22 to reduce the friction of the transmission rack 42 on the guide groove 22.

[0049] The drive unit 21 can adopt a mature DC servo motor from the prior art. The output shaft end of the motor is fitted with a transmission gear 231 via a key. The rotation state of the transmission gear 231 is controlled by the forward and reverse rotation of the DC servo motor. When the DC servo motor rotates and drives the transmission rack 42 to move away from the first connecting arm 1, since the first connecting end of the support unit is hinged to the arm body of the first connecting arm 1, as the second connecting end moves away from the first connecting arm 1, the first connecting arm 1 will move smoothly along the hinged direction with the second connecting arm 2. Figure 1 As shown, it rotates counterclockwise; similarly, when the DC servo motor reverses and the transmission rack 42 moves towards the direction closer to the first connecting arm 1, since the first connecting end of the support is hinged to the arm body of the first connecting arm 1, as the second connecting end moves closer to the first connecting arm 1, the first connecting arm 1 will move smoothly along the direction due to its hinged connection with the second connecting arm 2. Figure 1 Rotate clockwise as shown.

[0050] In some embodiments, the second connecting arm 2 has a hollow cavity within its body, and the guide groove 22 is located within the cavity. A guide rod connecting both ends of the second connecting arm 2 is provided within the cavity, and a guide ring is fitted onto the guide rod. The guide ring is fixedly connected to the transmission rack, allowing it to move smoothly along the body of the second connecting arm 2. To ensure the guide ring moves synchronously with the rotating rack, the length of the smooth surface should be the same as the movement length of the transmission rack 42. In this embodiment, the guide ring further enhances the connection stability between the transmission rack 42 and the second connecting arm 2.

[0051] In some embodiments, the drive unit 21 is disposed at the middle of the arm body of the second connecting arm 2, and the hinge point between the first connecting end of the support and the first connecting arm 1 is located at the middle of the first connecting arm 1. Compared to placing the drive unit 21 close to the joint pivot point of the first connecting arm 1 and the second connecting arm 2, placing the drive unit 21 at the middle of the arm body can effectively extend the drive arm of the first connecting arm 1; at the same time, the pivot joint is only used for switching rotation states and is not used as the main force application end. This arrangement can reduce the load on the pivot joint and is also beneficial for the later maintenance of the pivot joint.

[0052] In the above embodiment, in the initial state, the meshing position of the transmission rack 42 and the drive unit 21 is located at the lowermost end of the transmission rack 42. At this time, the included angle between the first connecting arm 1 and the second connecting arm 2 is the maximum opening angle. As the transmission rack 42 gradually moves away from the first connecting arm 1, the first connecting arm 1 can rotate relative to the second connecting arm 2, causing the opening angle to gradually decrease. When the meshing position of the transmission rack 42 and the drive unit 21 is located at the uppermost end of the transmission rack 42, the included angle between the first connecting arm 1 and the second connecting arm 2 is the minimum angle. It can also be seen that the rotation angle between the first connecting arm 1 and the second connecting arm 2 is affected by the movement path of the transmission rack 42; the longer the movement path of the transmission rack 42, the greater the movement angle between the first connecting arm 1 and the second connecting arm 2.

[0053] In some embodiments, the drive unit 21 is a linear drive motor, and the drive end of the linear drive motor is directly fixed to the second connecting end of the support unit. The drive end can reciprocate linearly along the arm direction of the second connecting arm 2, thereby constituting the movement of the second connecting end of the support unit on the second connecting arm 2.

[0054] In some embodiments, such as Figure 1 As shown, the support includes at least two connecting rods 41, with adjacent connecting rods 41 rotatably connected via damping shafts. Specifically, the support includes three connecting rods 41 rotatably connected in sequence, wherein the length of the middle connecting rod 41 is greater than the length of the connecting rods 41 at both ends, and each connecting rod 41 is rotatably connected via a damping shaft. With this configuration, when the first connecting arm 1 is subjected to an unexpected external force impact, it can buffer and dissipate the force on the first connecting arm 1, preventing sudden changes in the external force from causing a sudden change in the motion state of the first connecting arm 1 and damaging the drive unit 21.

[0055] It should be noted that the damping value preset by the damping shaft should be greater than the deformation force of the transmission rack 42 on each link 41. In other words, the movement of the transmission rack 42 driving the link 41 will not cause relative rotation between the links 41, but relative rotation will occur when they are subjected to an external force exceeding the preset damping value. This setting can ensure that the support part is in a normal connection state with the first connecting arm 1.

[0056] As an alternative implementation, other rotation limiting components can also be provided at the hinge points of each link 41. The preset force of the rotation limiting component can withstand the driving action of the transmission rack 42 and maintain the relative positioning of each link 41. However, when it is subjected to an external force exceeding the preset force, relative rotation will occur. Here, the rotation limiting component can adopt a mature structural component in the prior art.

[0057] In some embodiments, the robotic arm joint structure further includes a third connecting arm 3 and a diagonal brace 51, wherein the third connecting arm 3 is used to support the second connecting arm 2 and the first connecting arm 1, and the third connecting arm 3 is hinged to the second connecting arm 2; one end of the diagonal brace 51 is hinged to the second connecting arm 2, and the other end is slidably disposed on the arm body of the third connecting arm 3, and an elastic element is connected between the sliding end of the diagonal brace 51 and the third connecting arm 3, the elastic element having an elastic force that drives the diagonal brace 51 to move toward the second connecting arm 2.

[0058] In the above embodiment, since the diagonal brace 51, the second connecting arm 2 and the third connecting arm 3 form a triangular stable structure, the diagonal brace 51 can support the second connecting arm 2 when the mechanical claw 6 is holding a heavy object, thus further enhancing the structural stability between the third connecting arm 3 and the second connecting arm 2.

[0059] In some embodiments, the third connecting arm 3 has an internal mounting groove 31, and the sliding end is constrained within the mounting groove 31. The two ends of the elastic member are respectively connected to the bottom of the mounting groove 31 and the sliding end. As the second connecting arm 2 rotates relative to the third connecting arm 3, the end of the diagonal brace 51 connected to the body of the third connecting arm 3 will tend to move towards the second connecting arm 2 due to the action of the elastic member, thereby helping to maintain the connecting support function of the diagonal brace 51. Here, the elastic member can be a columnar spring or a connecting rod with elastic telescopic function.

[0060] It should be noted that the support and diagonal brace 51 structures in this embodiment can be applied to the joint structures of robotic arms in different positions, such as elbow arms and wrist arms. The first connecting arm 1, the second connecting arm 2, and the third connecting arm 3 described in this embodiment are all examples.

[0061] In some embodiments, a mechanical claw 6 is connected to the free end of the first connecting arm 1. The mechanical claw 6 includes two elastically open claw bodies. Here, the hinge point of each claw body is elastically opened by setting a torsion spring. The end of each claw body is fixedly connected to a steel wire. The steel wire is guided to the arm body of the first connecting arm 1 through a guide wheel on each claw body. A sliding rack is limited and constrained in the arm body of the first connecting arm 1. The sliding rack is fixedly connected to the steel wire and can be slidably arranged in the arm body of the first connecting arm 1. The sliding rack is driven to move by an external motor 11 set on the first connecting arm 1, thereby causing the sliding rack to pull the steel wire tight or loosen, thereby causing the mechanical claw 6 to contract under the action of the steel wire or open under the action of the elastic element.

[0062] It should be noted that the connection method between the sliding rack and the external motor 11 can refer to the connection method between the drive unit 21 and the transmission rack 42 described above; in addition, as Figure 5 and Figure 6 As shown, in some embodiments, the first connecting arm 1 has a guide section with a reduced inner diameter inside its body. A guide collar 12 is fitted onto the guide section, and the guide collar 12 is fixedly connected to the transmission rack on the first connecting arm 1. The guide collar can move smoothly along the body of the first connecting arm 1. In this embodiment, the guide collar can further improve the connection stability between the transmission rack on the first connecting arm 1 and the first connecting arm 1. Here, the structure of this guide collar can also be applied to the second connecting arm 2.

[0063] This application also provides a robotic arm that includes the robotic arm joint structure as described in one or more of the preceding embodiments, and thus has all the advantages of a robotic arm joint structure as described above.

[0064] In some embodiments, such as Figure 1 and Figure 5 As shown, the robotic arm provided in this application includes a base 7, a third connecting arm 3, a second connecting arm 2 and a first connecting arm 1 that are sequentially hinged to the base 7, wherein the free end of the first connecting arm 1 is connected to a mechanical claw 6, which is used to grip an item.

[0065] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this disclosure (including the claims) is limited to these examples; within the framework of this invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in the details for the sake of brevity.

[0066] The embodiments of this invention are intended to cover all such substitutions, modifications, and variations falling within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A robotic arm joint structure, characterized in that, include: The first and second connecting arms are hinged together. The support includes a first connecting end and a second connecting end, wherein the first connecting end is hinged to the arm body of the first connecting arm, and the second connecting end is slidably connected to the arm body of the second connecting arm; The second connecting arm is provided with a driving part on its body. The driving end of the driving part is connected to the support part in a transmission manner. The driving part can drive the support part to move along the body direction of the second connecting arm, so that the first connecting arm is driven by the support part to rotate relative to the second connecting arm. The support includes at least two connecting rods, and two adjacent connecting rods are rotatably connected by a damping shaft. The support includes three links that are rotatably connected in sequence, with the length of the middle link being greater than the length of the links at both ends.

2. The robotic arm joint structure according to claim 1, characterized in that, The second connecting arm is provided with a guide groove extending along its length. The second connecting end of the support is constrained in the guide groove and is configured to move along the direction of the guide groove under the driving force of the driving part.

3. The robotic arm joint structure according to claim 2, characterized in that, The second connecting end of the support is connected to a transmission rack, which is constrained in the guide groove. The driving end of the drive unit is connected to a transmission gear that moves synchronously with the driving end, and the transmission rack meshes with the transmission gear.

4. The robotic arm joint structure according to claim 3, characterized in that, The second connecting arm has a hollow cavity inside its body. The guide groove is located in the cavity. The cavity is provided with guide rods that connect the two ends of the second connecting arm. A guide ring is sleeved on the guide rod, and the guide ring is fixedly connected to the transmission rack.

5. The robotic arm joint structure according to claim 1, characterized in that, The drive unit is a DC servo motor capable of forward and reverse rotation.

6. The robotic arm joint structure according to any one of claims 1-5, characterized in that, Also includes: A third connecting arm is used to support the second connecting arm and the first connecting arm, and the third connecting arm is hinged to the second connecting arm; The diagonal brace has one end hinged to the second connecting arm and the other end slidably mounted on the body of the third connecting arm. An elastic element is connected between the sliding end of the diagonal brace and the third connecting arm, and the elastic element has an elastic force that drives the diagonal brace to move toward the second connecting arm.

7. The robotic arm joint structure according to claim 6, characterized in that, The third connecting arm has a mounting groove, and the sliding end is limited and constrained in the mounting groove. The two ends of the elastic member are respectively connected to the bottom of the mounting groove and the sliding end.

8. A robotic arm, characterized in that, Includes the robotic arm joint structure as described in any one of claims 1-7.

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