Coaxial equidistant linear drive joint

Abstract

The utility model discloses a coaxial equidistant linear drive joint, which relates to the technical field of manipulators and comprises a finger tip, a first joint structure, a second joint structure, a third joint structure and a base. The finger tip is connected with one end of the first joint structure, and the other end of the first joint structure is connected with one end of the second joint structure; the other end of the second joint structure is connected with the third joint structure; and the third joint structure is connected with the base. The driving joint can be miniaturized or large, the long-distance energy transmission pipeline can enable the driving joint to have enough force to execute a driving task, meanwhile, the size of the driving joint can be made smaller and lighter under the permissible of materials, and due to the fact that the driving joint is used to be separated from a driving source, the driving joint is more compact. Therefore, insufficient energy caused by too small size of the driving joint can be avoided.

Description

Technical Field

[0001] This utility model relates to the field of robotic arm technology, and in particular to a coaxial equidistant linear drive joint. Background Technology

[0002] Robotics has always been a cutting-edge technology in this century, and mechanical fingers are a particularly challenging area of ​​research in robotics.

[0003] A search revealed that Chinese patent document CN210041673U discloses a piezoelectric motor support for a mechanical finger joint, comprising a pair of rotors, a pair of stators, a pair of piezoelectric ceramic plates, three electrode plates, and a shaft assembly. The shaft assembly includes a rotating shaft, bearings, and retaining rings. The piezoelectric ceramic plates and electrode plates are sequentially mounted on the middle of the rotating shaft in a structure of electrode plate, piezoelectric ceramic plate, electrode plate, piezoelectric ceramic plate, electrode plate, and electrode plate, and are pressed between the pair of stators by the stators. The pair of rotors are rotatably mounted on the rotating shaft via bearings, with the inner end faces of the rotors fitting against the outer end faces of the stators. This patent has a simple structure, is easy to manufacture and assemble, and will not interfere with the operation of the mechanical finger and the piezoelectric motor, making it suitable for use in robots.

[0004] Based on research and existing technology, current bionic robotic hands primarily rely on motors directly placed at each joint to drive joint movement. This driving mode suffers from the limitation of large motors and small joints, making it impossible to miniaturize the motors. Conversely, miniaturizing the motors results in insufficient power to drive small joints, hindering effective load output. Traditional driving methods typically involve single-wire drive of multiple joints simultaneously, leading to interference between joints and preventing independent operation. Using multi-wire drives to individually drive multiple joints causes severe interlocking, resulting in joints either failing to move properly or exhibiting excessive energy loss and severe mechanical wear due to interference. Utility Model Content

[0005] The purpose of this invention is to provide a coaxial equidistant linear drive joint to solve the problems mentioned in the background art.

[0006] The technical solution of this utility model is: a coaxial equidistant linear drive joint, including a fingertip, a first joint structure, a second joint structure, a third joint structure and a base, wherein the outer contours of the first joint structure and the second joint structure are both strip-shaped and can be bent at ninety degrees.

[0007] The fingertip is connected to one end of the first joint structure, and the other end of the first joint structure is connected to one end of the second joint structure.

[0008] The other end of the second joint structure is connected to the third joint structure;

[0009] The third joint structure is connected to the base;

[0010] The first joint structure, the second joint structure, and the third joint structure are all connected to a wire-driven mechanism.

[0011] Preferably, the first joint structure includes a first anterior joint and a first middle joint, and the second joint structure includes a second anterior joint and a second middle joint; one side of the first anterior joint is a square plate, and a long plate with a semi-circular end protrudes outward from the middle of one side of the square plate; the other side of the square plate of the first anterior joint is fixed to the fingertip; an annular groove for limiting the position of the line is provided at the middle of the semi-circular end of the first anterior joint; an arc-shaped wire hole connected to and coaxially arranged with the annular groove is provided inside the long plate of the first anterior joint; two second threading holes are provided on the plate surface of the first anterior joint, respectively located on both sides of the long plate, and the central axis of the second threading hole is coplanar with the central axis of the semi-circular end of the long plate; the external structures of the first anterior joint, the second anterior joint, and the third joint structure are consistent.

[0012] Preferably, the first joint structure further includes a second intermediate joint, and the second joint structure further includes a second intermediate joint. Two first threading holes are provided on the inner side of the first intermediate joint. The central axis of the first threading holes is located on the middle surface of the first intermediate joint. The first intermediate joint and the second intermediate joint have the same specifications.

[0013] Preferably, both sides of the long plate are fixed with cylinders coaxially arranged with their semi-circular ends, and the second threading hole passes through the cylinders. The outer sides of the first middle joint, the second middle joint, and the base are respectively fixed with a first finger plate, a second finger plate, and a third finger plate. Rotation holes are opened on the outer sides of the first finger plate, the second finger plate, and the third finger plate. The cylinder on the first front joint is rotatably installed in the rotation hole on the first finger plate, the cylinder on the second front joint is rotatably installed in the rotation hole on the second finger plate, and the cylinder on the third joint structure is rotatably installed in the rotation hole on the third finger plate.

[0014] Preferably, the first joint structure further includes a first rear joint, the two ends of which are fixed to a first middle joint and a second front joint, respectively. The interior of the first rear joint has two first guide holes, the two ends of which are located on the two ends of the first rear joint. The two holes at one end of the two first guide holes are coaxially arranged with the two first threading holes on the first middle joint, and the two holes at one end of the two second guide holes are coaxially arranged with the two second threading holes on the second front joint.

[0015] Preferably, the second joint structure further includes a second rear joint, the interior of which has two third threading holes and two second guide holes. One end of each of the two second guide holes is connected to the two third threading holes and the other end extends out of the second rear joint. The two ends of the second rear joint are fixed to the second middle joint and the third joint structure, respectively. The inner sidewall of the second middle joint has two fourth threading holes. The two third threading holes are coaxially arranged with the two fourth threading holes on the second middle joint and with the two second threading holes on the third joint structure. One end of each of the two second guide holes is coaxially arranged with the two first threading holes on the second middle joint.

[0016] Preferably, the wire-driven mechanism includes a first drive wire, the middle end of which is fixed in the arc hole of the first front joint and fixed in the arc hole. The two ends of the first drive wire pass through two first threading holes on the first middle joint, two guide wire holes on the first rear joint, two second threading holes on the second front joint, a fourth threading hole on the second middle joint, two third threading holes on the second rear joint, and two second threading holes on the third joint structure, respectively. Both ends of the first drive wire are fitted with a first drive tube.

[0017] Preferably, the wire drive mechanism further includes a second drive wire, the middle end of which is located in the arc hole of the second front joint and fixed in the arc hole. The two ends of the second drive wire pass through the fourth wire hole on the second middle joint, the two second guide wire holes on the second rear joint, and the two second wire holes on the third joint structure, respectively. Both ends of the second drive wire are fitted with a second drive tube.

[0018] Preferably, the wire-driven mechanism further includes a third drive line, the middle end of which is located in and fixed within the arc-shaped hole of the third joint structure, and both ends of the third drive line are fitted with third drive tubes.

[0019] Preferably, a wire movement groove is provided on one side of the first wire hole.

[0020] This utility model provides an improved coaxial equidistant linear drive joint, which has the following improvements and advantages compared to the prior art:

[0021] Firstly, this utility allows for the miniaturization or enlargement of drive joints. Long-distance energy transmission channels enable drive joints to perform drive tasks with sufficient power. At the same time, it allows drive joints to be made smaller and lighter within the limits of material availability. Since the drive joint is separated from the drive source, the drive joint will not suffer from insufficient energy due to its small size.

[0022] Secondly, this invention allows large mechanical equipment to obtain sufficient energy, avoiding the limitations of traditional drive methods that install the drive source at the joint's moving position, preventing joint miniaturization or requiring a heavier drive source to achieve greater driving torque. This results in an invisible increase in the drive weight on top of the joint's original weight, leading to the need for even larger and heavier drive sources to achieve greater power. This increased drive source size and weight further increases the size and weight of the drive joint, creating a vicious cycle. This invention uses a separation technology for the drive joint, drive source, and energy transmission channels, minimizing the weight of the drive joint to obtain sufficient force for it to move. When the drive joint lacks sufficient force, the drive source can be continuously enlarged without affecting the original weight and size of the drive joint. Therefore, within material limits, even the largest and heaviest drive joints can be moved by remotely adjusting the output energy of the drive source. This makes it possible to realize various drive devices requiring actuation, such as large mechanical equipment, small nanorobots, or humanoid mechs.

[0023] Secondly, this utility model utilizes the principle of coaxial equidistance to minimize motion interference between joints. Theoretically, this technology allows joints to be made small or large enough, provided the materials are suitable, without affecting energy output or interfering with each other's movements. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the specific embodiments of this utility model or the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the finger joint structure for this practical application;

[0026] Figure 2 This is a three-dimensional structural diagram of the first joint structure, the second joint structure, the third joint structure, and the wire drive mechanism of this utility model.

[0027] Figure 3 This is a schematic diagram of the first drive line installation in this utility model;

[0028] Figure 4 This is a perspective view of the first joint structure, the second joint structure, and the third joint structure of this utility model;

[0029] Figure 5 This is a schematic diagram of the installation of the second drive line in this utility model;

[0030] Figure 6 Perspective views of the second and third joint structures of this utility model;

[0031] Figure 7 This is a schematic diagram of the installation of the third drive line in this utility model;

[0032] Figure 8 This is a perspective view of the third joint structure of this utility model;

[0033] Figure 9 for Figure 4 A sectional view;

[0034] Figure 10 for Figure 9 A magnified structural diagram at point A;

[0035] Figure 11 This is a first-view three-dimensional structural diagram of the first joint of this utility model;

[0036] Figure 12 This is a two-dimensional structural diagram of the first joint of this utility model from a second perspective.

[0037] Figure 13 This is a perspective view of the first joint in this utility model;

[0038] Figure 14 This is a first-view three-dimensional structural diagram of the first posterior joint of this utility model;

[0039] Figure 15 This is a two-dimensional structural diagram of the first posterior joint from a second perspective in this practical application.

[0040] Figure 16 This is a perspective view of the first posterior joint of this utility model;

[0041] Figure 17 This is a three-dimensional structural diagram of the first anterior joint from a first-view perspective in this practical application.

[0042] Figure 18 This is a three-dimensional structural diagram of the first anterior joint from a second perspective in this practical application;

[0043] Figure 19 This is a perspective view of the first anterior joint of this utility model;

[0044] Figure 20 This is a first-view three-dimensional structural diagram of the second posterior joint of this utility model;

[0045] Figure 21 This is a three-dimensional structural diagram of the second posterior joint from a second perspective, which is a practical application.

[0046] Figure 22 This is the second rear-view perspective view of this utility model;

[0047] Figure 23 This is a first-view three-dimensional structural diagram of the second joint of this utility model;

[0048] Figure 24 This is a three-dimensional structural diagram of the second joint from a second perspective in this practical application;

[0049] Figure 25 This is a perspective view of the second joint in this utility model;

[0050] Figure 26 This is another schematic diagram of the finger joints used in this practical application.

[0051] Figure label:

[0052] 1. Fingertip; 2. First fingertip plate; 3. Second fingertip plate; 4. Third fingertip plate; 5. Base; 6. First joint structure; 601. First anterior joint; 602. First middle joint; 603. First posterior joint; 604. First threading hole; 605. Thread groove; 606. First guide wire hole; 607. Arc-shaped wire hole; 608. Annular wire groove; 609. Cylinder; 610. Second threading hole; 7. Second joint structure; 701. Second anterior joint; 702. Second middle joint; 703. Second posterior joint; 704. Third threading hole; 705. Second guide wire hole; 706. Fourth threading hole; 8. Third joint structure; 9. First drive wire; 10. First drive tube; 11. Third drive wire; 12. Third drive tube; 13. Second drive wire; 14. Second drive tube. Detailed Implementation

[0053] The present invention will now be described in detail, and the technical solutions in the embodiments of the present invention will be clearly and completely described. 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.

[0054] This utility model provides an improved coaxial equidistant linear drive joint. The technical solution of this utility model is as follows:

[0055] like Figures 1 to 25 As shown, this utility model provides a coaxial equidistant linear drive joint, including a fingertip 1, a first joint structure 6, a second joint structure 7, a third joint structure 8, and a base 5. The fingertip 1 is connected to one end of the first joint structure 6, and the other end of the first joint structure 6 is connected to one end of the second joint structure 7.

[0056] The other end of the second joint structure 7 is connected to the third joint structure 8;

[0057] The third joint structure 8 is connected to the base;

[0058] The first joint structure, the second joint structure 7, and the third joint structure 8 are connected together to a wire drive mechanism;

[0059] As can be seen from the above brief description, each joint of this utility model is independently set, and the wire drive mechanism used to drive the operation of each joint is independently set on the outside, which makes the entire mechanical finger lightweight.

[0060] Specifically, in conjunction with the appendix Figure 11-25As shown, the first joint structure 6 includes a first anterior joint 601 and a first middle joint 602, and the second joint structure 7 includes a second anterior joint 701 and a second middle joint 702. One side of the first anterior joint 601 is a square plate, and a long plate with a semi-circular end protrudes outward from the middle of one side of the square plate. The other side of the square plate of the first anterior joint 601 is fixed to the fingertip 1. An annular groove 608 for limiting the position of the line is opened at the middle of the semi-circular end of the first anterior joint 601. An arc-shaped wire hole 607 connected to and coaxially arranged with the annular groove 608 is opened inside the long plate of the first anterior joint 601. Two second threading holes 610 are opened on the plate surface of the first anterior joint 601, located on both sides of the long plate, and the central axis of the second threading hole 610 is aligned with the fingertip 1. The semicircular ends of the long plate are coplanar. The external structures of the first front joint 601, the second front joint 701, and the third joint structure 8 are identical. The first joint structure 6 also includes a second middle joint 702, and the second joint structure 7 also includes a second middle joint 702. Two first threading holes 604 are opened on the inner side of the first middle joint 602. The central axis of the first threading holes 604 is located on the middle surface of the first middle joint 602. The first middle joint 602 and the second middle joint 702 are identical in size. Both sides of the long plate are fixed with cylinders 609 coaxially arranged with their semicircular ends, and the second threading holes 610 pass through the cylinders 609. The outer sides of the first middle joint 602, the second middle joint 702, and the base 5 are respectively fixed with a first finger plate 2, a second finger plate 2, and a second finger plate 3. The head plate 3 and the third finger head plate 4, as well as the outer sides of the first finger head plate 2, the second finger head plate 3, and the third finger head plate 4, all have rotating holes. A cylinder 609 on the first anterior joint 601 is rotatably mounted in the rotating hole on the first finger head plate 2. A cylinder 609 on the second anterior joint 701 is rotatably mounted in the rotating hole on the second finger head plate 3. A cylinder 609 on the third joint structure 8 is rotatably mounted in the rotating hole on the third finger head plate 4. The first joint structure 6 also includes a first posterior joint 603. The two ends of the first posterior joint 603 are respectively fixed to the first middle joint 602 and the second anterior joint 701. Two first guide holes 606 are formed inside the first posterior joint 603, with the two ends of the first guide holes 606 located at the first posterior joint 601. At both ends of joint 703, two holes at one end of the two first guide wire holes 606 are coaxially arranged with two first threading holes 604 on the first intermediate joint 602, and two holes at one end of the two second guide wire holes 705 are coaxially arranged with two second threading holes 610 on the second front joint 701. The second joint structure 7 also includes a second rear joint 703. Two third threading holes 704 and two second guide wire holes 705 are provided inside the second rear joint 703. One end of each of the two second guide wire holes 705 is connected to the two third threading holes 704, and the other end extends out of the second rear joint 703. Both ends of the second rear joint 703 are fixed to the second intermediate joint 702 and the third joint structure 8, respectively.Two fourth threading holes 706 are provided on the inner sidewall of the second intermediate joint 702. Two third threading holes 704 are coaxially arranged with the two fourth threading holes 706 on the second intermediate joint 702, and the two third threading holes 704 are coaxially arranged with the two second threading holes 610 on the third joint structure 8. One end of each of the two second guide holes 705 is coaxially arranged with the two first threading holes 604 on the second intermediate joint 702.

[0061] The following explanation is provided for the first joint structure 6, the second joint structure 7, and the third joint structure 8:

[0062] First, the various wire holes are designed to facilitate the threading of the drive wires of the wire-driven mechanism described below. At the same time, the distribution of each wire hole is different, so that each drive wire can be kept taut and work independently as much as possible, so as to avoid interference with each other and prevent production line issues.

[0063] Second, where materials permit, the three joint structures, namely the first joint structure 6, the second joint structure 7, and the third joint structure 8, can be made small or large, and each joint is independent, thereby enabling the joints to focus on non-interfering motion and enabling the drive source of the wire-driven mechanism to focus on energy supply, truly achieving drive source and energy transmission.

[0064] Specifically, in conjunction with the appendix Figure 2-9 and appendix Figure 11-25As shown, the wire-driven mechanism includes a first drive wire 9. The middle end of the first drive wire 9 is fixed inside the arc-shaped wire hole 607 of the first front joint 601. The two ends of the first drive wire 9 pass through two first wire holes 604 on the first middle joint 602, two guide wire holes on the first rear joint 603, two second wire holes 610 on the second front joint 701, a fourth wire hole 706 on the second middle joint 702, two third wire holes 704 on the second rear joint 703, and two second wire holes 610 on the third joint structure 8, respectively. Both ends of the first drive wire 9 are fitted with a first drive tube 10. The wire-driven mechanism also includes a second drive wire 13. The middle end of the second drive wire 13 is located inside the arc-shaped wire hole 607 of the second front joint 701 and is fixed inside the arc-shaped wire hole 607. The two ends of the second drive wire 13 pass through the fourth wire hole 706 on the second middle joint 702, respectively. The second guide wire hole 705 on the second rear joint 703 and the second wire hole 610 on the third joint structure 8 are provided with two second drive tubes 14 at both ends of the second drive wire 13. The wire drive mechanism also includes a third drive wire 11, the middle end of which is located in the arc hole 607 of the third joint structure 8 and fixed in the arc hole 607. The third drive wire 11 is provided with third drive tubes 12 at both ends. It can be seen that each joint structure is driven by a separate drive wire. Each joint rotation does not require a single motor to be installed, which allows each joint to be miniaturized or enlarged. The wire drive form can realize long-distance energy transmission, allowing the drive joint to perform the drive task with sufficient force. At the same time, the drive joint can be made smaller and lighter within the material limits. Since the drive joint is separated from the drive source, the drive joint will not be insufficient in energy due to its small size.

[0065] Specifically, in conjunction with the appendix Figure 2-10 As shown, a wire movement groove 605 is provided on one side of the first wire hole 604. It should be further explained that the inflection point of the wire movement groove 605 is concentric with the semicircle of the long plate. This way, when each front joint rotates, it will not pull other drive lines that are not involved in the drive, ensuring that each drive line can work relatively independently.

[0066] To supplement the above:

[0067] The specific outer contour shape of each posterior joint structure is not limited, and... Figure 26For example, the second posterior joint 703 is twisted, and the internal wire hole of the posterior joint will also change accordingly. The wire holes of the mating surfaces of the posterior joint and the middle joint must be aligned. This ensures that the second drive line 13 can be parallel to the annular groove of the second anterior joint 608 when it passes through the corresponding middle joint, ensuring that each joint of the finger can rotate normally. Thus, as long as each drive line can be parallel to the annular groove when it passes through the corresponding middle joint, each middle joint and the posterior joint can undergo a certain shape change.

[0068] The setting of the linear groove is related to the range of rotation of each joint of the finger. Figure 9 and Figure 10 The reason why the corner of the linear groove is right angle is because the joints of the fingers can rotate 90 degrees. This is just a reference. No matter how big the angle of the corner of the linear groove is, the inflection point of the linear groove must be set coaxially with the cylinder.

[0069] Combining the above, we can see from the first and second points that the coaxial equidistant principle minimizes motion interference between joints.

[0070] Working principle:

[0071] When the fingertip 1 needs to rotate, pull one end of the first drive line 9. Since the middle end of the first drive line 9 is fixed in the arc hole 607 of the first front joint 601 and fixed in the arc hole 607, and since the cylinder 609 on the first front joint 601 is rotatably installed in the rotation hole on the first finger plate 2, pulling one end of the first drive line 9 at this time can make the first front joint 601 rotate around the central axis of the rotation hole on the first finger plate 2 with the fingertip 1.

[0072] When the first joint structure 6 needs to be rotated, pull one end of the second drive line 13. Since the middle end of the second drive line 13 is located in the arc hole 607 of the second front joint 701 and is fixed in the arc hole 607, and since the cylinder 609 on the second front joint 701 is rotatably installed in the rotation hole on the second finger plate 3, pulling one end of the second drive line 13 at this time can make the first joint structure 6 of the second front joint 701 rotate around the central axis of the rotation hole on the second finger plate 3.

[0073] When the first joint structure 6 and the second joint structure 7 need to rotate, pull one end of the third drive line 11. Since the middle end of the third drive line 11 is located in the arc hole 607 of the second front joint 701 and is fixed in the arc hole 607, and since the cylinder 609 on the third joint structure 8 is rotatably installed in the rotation hole on the third finger plate 4, pulling one end of the third drive line 11 at this time can make the first joint structure 6 and the second joint structure 7 of the third joint structure 8 rotate around the central axis of the rotation hole on the second finger plate 3.

[0074] In summary, by pulling different drive lines, the entire mechanical finger can perform different bending operations. This eliminates the need for a separate motor at each joint rotation point, allowing for the miniaturization or enlargement of individual joints. Furthermore, the wire drive system enables long-distance energy transmission, allowing the drive joints to perform driving tasks with sufficient force. It also allows the drive joints to be made smaller and lighter within the limits of material availability. Since the drive joints are separated from the drive source, the drive joints will not suffer from insufficient energy due to excessively small size.

[0075] The foregoing description enables those skilled in the art to implement or use this utility model. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this utility model. Therefore, this utility model is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A coaxial equidistant line driven joint comprising a finger tip (1), a first joint structure (6), a second joint structure (7), a third joint structure (8) and a base (5), characterized in that: The fingertip (1) is connected to one end of the first joint structure (6), and the other end of the first joint structure (6) is connected to one end of the second joint structure (7); The other end of the second joint structure (7) is connected to the third joint structure (8); The third joint structure (8) is connected to the base (5); The first joint structure, the second joint structure (7), and the third joint structure (8) are connected together to form a wire drive mechanism.

2. A concentric loxodrome driven joint according to claim 1, wherein: The first joint structure (6) includes a first anterior joint (601) and a first middle joint (602), and the second joint structure (7) includes a second anterior joint (701) and a second middle joint (702). One side of the first front joint (601) is a square plate. The middle of one side of the square plate protrudes outward to form a long plate with one end being semi-circular. The other side of the square plate of the first front joint (601) is fixed to the fingertip (1). An annular groove (608) for limiting the position of the line is provided at the middle of the semi-circular end of the first front joint (601). An arc-shaped wire hole (607) connected to and coaxially arranged with the annular groove (608) is provided inside the long plate of the first front joint (601). Two second threading holes (610) are provided on the plate surface of the first front joint (601) respectively located on both sides of the long plate. The central axis of the second threading hole (610) is coplanar with the central axis of the semi-circular end of the long plate. The external structures of the first front joint (601), the second front joint (701) and the third joint structure (8) are consistent.

3. A concentric loxodrome driven joint according to claim 2, wherein: The first joint structure (6) further includes a second intermediate joint (702), and the second joint structure (7) further includes a second intermediate joint (702). Two first threading holes (604) are opened on the inner side of the first intermediate joint (602). The central axis of the first threading hole (604) is located on the middle surface of the first intermediate joint (602). The first intermediate joint (602) and the second intermediate joint (702) have the same specifications.

4. A concentric loxodrome driven joint according to claim 3, wherein: Both sides of the long plate are fixed with cylinders (609) coaxially arranged with their semi-circular ends, and the second thread hole (610) passes through the cylinders (609). The outer sides of the first middle joint (602), the second middle joint (702) and the base (5) are respectively fixed with a first finger plate (2), a second finger plate (3) and a third finger plate (4). The outer sides of the first finger plate (2), the second finger plate (3) and the third finger plate (4) are all provided with rotating holes. The cylinder (609) on the first front joint (601) is rotatably installed in the rotating hole on the first finger plate (2), the cylinder (609) on the second front joint (701) is rotatably installed in the rotating hole on the second finger plate (3), and the cylinder (609) on the third joint structure (8) is rotatably installed in the rotating hole on the third finger plate (4).

5. A concentric loxodrome driven joint according to claim 4, wherein: The first joint structure (6) also includes a first rear joint (603). The two ends of the first rear joint (603) are fixed to the first middle joint (602) and the second front joint (701) respectively. The first rear joint (603) has two first guide hole (606) inside. The two ends of the first guide hole (606) are located on the two ends of the first rear joint (603) respectively. The two holes on one end of the two first guide hole (606) are coaxially arranged with the two first threading holes (604) on the first middle joint (602) respectively. The two holes on one end of the two second guide hole (705) are coaxially arranged with the two second threading holes (610) on the second front joint (701) respectively.

6. A coaxial equidistant linear drive joint according to claim 5, characterized in that: The second joint structure (7) also includes a second rear joint (703). Two third threading holes (704) are formed inside the second rear joint (703). Two second guide holes (705) are formed inside the second rear joint (703). One end of each of the two second guide holes (705) is connected to one of the two third threading holes (704), and the other end extends to the outside of the second rear joint (703). Both ends of the second rear joint (703) are connected to the second intermediate joint (702) and the third… The joint structure (8) is fixed. The inner wall of the second middle joint (702) has two fourth threading holes (706). The two third threading holes (704) are coaxially arranged with the two fourth threading holes (706) on the second middle joint (702). The two third threading holes (704) are coaxially arranged with the two second threading holes (610) on the third joint structure (8). One end of the two second guide wire holes (705) is coaxially arranged with the two first threading holes (604) on the second middle joint (702).

7. A coaxial equidistant linear drive joint according to claim 6, characterized in that: The wire drive mechanism includes a first drive wire (9), the middle end of which is fixed in the arc hole (607) of the first front joint (601). The two ends of the first drive wire (9) pass through two first wire holes (604) on the first middle joint (602), two guide wire holes on the first rear joint (603), two second wire holes (610) on the second front joint (701), a fourth wire hole (706) on the second middle joint (702), two third wire holes (704) on the second rear joint (703), and two second wire holes (610) on the third joint structure (8). Both ends of the first drive wire (9) are fitted with a first drive tube (10).

8. A coaxial equidistant linear drive joint according to claim 7, characterized in that: The wire drive mechanism also includes a second drive line (13). The middle end of the second drive line (13) is located in the arc hole (607) of the second front joint (701) and fixed in the arc hole (607). The two ends of the second drive line (13) pass through the fourth wire hole (706) on the second middle joint (702), the two second guide wire holes (705) on the second rear joint (703), and the two second wire holes (610) on the third joint structure (8), respectively. The two ends of the second drive line (13) are fitted with second drive tubes (14).

9. A coaxial equidistant linear drive joint according to claim 8, characterized in that: The wire drive mechanism also includes a third drive line (11), the middle end of which is located in the arc hole (607) of the third joint structure (8) and fixed in the arc hole (607). Both ends of the third drive line (11) are fitted with third drive tubes (12).

10. A coaxial equidistant linear drive joint according to any one of claims 3-9, characterized in that: A wire movement groove (605) is provided on one side of the first wire hole (604).

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