CN108177159B - A high-load-bearing universal joint, a joint of a robotic arm and a flexible robotic arm - Google Patents

Abstract

The present invention relates to the technical field of robots, and provides a high-load universal joint, a joint of a mechanical arm and a flexible mechanical arm. The second sliding ball includes a first cavity with a spherical inner surface, and the first sliding ball is rotatably arranged in the first cavity. In the cavity, the first sliding ball can slide along the inner surface of the first cavity. The ball seat includes a second cavity whose inner surface is spherical. The second sliding ball is rotatably arranged in the second cavity, and the second sliding ball can slide along the inner surface of the first cavity. The inner surface of the second cavity slides to ensure the contact area between the first sliding ball and the second sliding ball and the contact area between the second sliding ball and the ball seat, thereby improving the load capacity. The first limit structure and the second limit structure are set to respectively limit the rotation of the first slide along its latitude and the rotation of the second slide ball along its weft, so that the movement between the first slide and the second slide Under the premise of realizing the universal rotation with the combination between the second sliding ball and the ball seat, the problem of under-actuation of the common ball twist structure is solved.

Description

A high-load-bearing universal joint, a joint of a robotic arm and a flexible robotic arm

technical field

The invention relates to the technical field of robots, in particular to a high-load universal joint, a mechanical arm joint and a flexible mechanical arm.

Background technique

The flexible manipulator is usually provided with a plurality of joints connected to each other through joints, and the joints are respectively driven to move around the joints by a driving device to realize the mutual movement between the joints, so that the flexible manipulator as a whole realizes free bending. There is a rotatable part between two adjacent joints of the flexible robotic arm. Corresponding joints are set in this part to connect the two adjacent joints. In the prior art, the joints are mainly set in the following three types: The elastic joint that uses the elastic element as the rotatable part, the second is the universal joint that uses the cross universal joint as the rotatable part, and the third is the ball articulated joint that uses the ball articulated as the rotatable part. In actual use, the bearing capacity of the first and second types of joints is small, making the joints relatively fragile. Although the bearing capacity of the third type of joint is high, the degree of freedom of rotation around the direction of the arm among the three degrees of freedom of the ball joint is limited when driving. It will not be constrained, so there is an underactuation problem, which makes the drive control inaccurate. Therefore, most of the current spherical universal joints cannot be used in practice due to the complex structure design. Therefore, the existing flexible manipulator joints still have insufficient bearing capacity. The problem.

Therefore, it is necessary to provide a new technical solution to solve the above-mentioned problems in the prior art.

Contents of the invention

The technical problem to be solved by the present invention is to provide a high load-bearing universal joint, a mechanical arm joint and a flexible mechanical arm.

The technical solution adopted by the present invention to solve the problems of the technologies described above is:

A high-load universal joint is provided, including a first sliding ball, a second sliding ball, a ball seat and a gland, wherein:

A connecting portion is fixedly arranged on the first sliding ball;

The second sliding ball includes a first cavity with a spherical inner surface, the first sliding ball is rotatably arranged in the first cavity, and the first sliding ball can move along the inner surface of the first cavity slide;

The ball seat includes a second cavity with a spherical inner surface, the second sliding ball is rotatably arranged in the second cavity, and the second sliding ball can slide along the inner surface of the second cavity;

The gland is fixedly installed on the ball seat, and the gland fixes the first sliding ball and the second sliding ball in the second cavity;

A first limiting structure is arranged between the first sliding ball and the second sliding ball, which is used to limit the rotational movement of the first sliding ball along its parallel direction, and the second sliding ball and the second sliding ball A second limiting structure is provided between the ball seats for limiting the rotational movement of the second sliding ball along its parallel direction.

As an improvement of the above technical solution, the first limiting structure includes a first limiting body and a first limiting groove fitted in cooperation, and the first limiting body can slide in the first limiting groove, so The second limiting structure includes a second limiting body and a second limiting groove that are fitted together, and the second limiting body can slide in the second limiting groove.

As a further improvement of the above technical solution, the first limiting groove is arranged on the inner surface of the first cavity and is recessed inward, the first limiting groove is arranged along the meridian of the first cavity, and the first limiting groove is arranged along the meridian of the first cavity. A limiting body is arranged on the outer surface of the first sliding ball and protrudes outward, the first limiting body is arranged along the meridian of the first sliding ball, and the first sliding ball is installed on the When in the first cavity, the first limiting body is located in the first limiting groove.

As a further improvement of the above technical solution, the second limiting groove is arranged on the inner surface of the second cavity and is recessed inward, the second limiting groove is arranged along the weft of the second cavity, the first Two limiting bodies are arranged on the outer surface of the second sliding ball and protrude outward, the second limiting body is arranged along the warp of the second sliding ball, and the second sliding ball is installed on the When in the second cavity, the second limiting body is located in the second limiting groove, and the first limiting groove and the second limiting body intersect in space.

As a further improvement of the above technical solution, the second sliding ball is hemispherical and includes two hemispherical shells, and one of the hemispherical shells is detachably connected to the other of the hemispherical shells.

As a further improvement of the above technical solution, the hemispherical shell includes a mounting edge, the two hemispherical shells are fixedly connected by the mounting edge to form the second sliding ball, and the two mounting edges together form the second sliding ball. limiter.

As a further improvement of the above technical solution, the ball seat is hemispherical as a whole, the second cavity is a hemispherical cavity, the gland is fixedly installed on the upper part of the ball seat, and the gland is provided with a A through hole for the first sliding ball to pass through, the inner wall of the through hole is a spherical surface whose diameter is consistent with the diameter of the inner surface of the second cavity.

As a further improvement of the above technical solution, a pair of relief grooves is further provided on the gland corresponding to the second position limiting groove, and the second position limiting body can slide in the relief grooves.

Also provided is a mechanical arm joint, comprising a joint body and the above-mentioned high-load universal joint, the joint body is fixedly connected to the connecting portion or the ball seat.

A mechanical arm is also provided, including a driving device and several above-mentioned mechanical arm joints, the mechanical arm joints are sequentially connected, and the driving device is used to drive the mechanical arm joints to move around the high load-bearing universal joint.

The beneficial effects of the present invention are:

In the high-load universal joint of the present invention, a second sliding ball is provided between the first sliding ball and the ball seat. The second sliding ball includes a first cavity whose inner surface is a spherical surface. The first sliding ball is rotatably arranged on the first sliding ball. In the cavity, the first sliding ball can slide along the inner surface of the first cavity, the ball seat includes a second cavity whose inner surface is spherical, the second sliding ball is rotatably arranged in the second cavity, and the second sliding ball can slide along the inner surface of the first cavity The inner surface of the second cavity slides to ensure the contact area between the first sliding ball and the second sliding ball, the contact area between the second sliding ball and the ball seat, improve the load capacity, and set the first limiting structure and the second The two position-limiting structures limit the rotation of the first sliding ball along its latitude and the rotation of the second sliding ball along its latitude respectively, so that the movement between the first sliding ball and the second sliding ball is consistent with the second sliding ball and the ball seat. Under the premise of realizing the universal rotation through the combination of the two parts, the problem of under-actuation of the ordinary ball joint structure is solved. The mechanical arm joint and the flexible mechanical arm including the above-mentioned high-load universal joint also have the above-mentioned technical effects.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly describe the drawings that need to be used in the description of the embodiments:

Fig. 1 is a schematic diagram of the overall structure of an embodiment of the high-load universal joint of the present invention;

Fig. 2 is the split schematic diagram of the embodiment shown in Fig. 1;

Fig. 3 is a structural schematic diagram of an embodiment of a mechanical arm joint of the present invention;

Fig. 4 is a schematic structural view of an embodiment of the flexible robotic arm of the present invention.

Detailed ways

The idea, specific structure and technical effects of the present invention will be clearly and completely described below in conjunction with the embodiments and accompanying drawings, so as to fully understand the purpose, features and effects of the present invention. Apparently, the described embodiments are only some of the embodiments of the present invention, rather than all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts belong to The protection scope of the present invention. In addition, all the connection/connection relationships involved in the patent do not simply refer to the direct connection of components, but mean that a better connection structure can be formed by adding or reducing connection accessories according to specific implementation conditions. The orientation descriptions of up, down, left, right, etc. involved in the present invention are only relative to the mutual positional relationship of the various components of the present invention in the drawings. The various technical features in the present invention can be combined interactively on the premise of not conflicting with each other.

Embodiment one:

Figure 1 is a schematic diagram of the overall structure of an embodiment of the high-load universal joint of the present invention, and Figure 2 is a schematic diagram of the disassembly of the embodiment shown in Figure 1, while referring to Figures 1 and 2, the high-load universal joint includes the first sliding ball 100 , the second sliding ball 200 , the ball seat 300 and the gland 400 .

The first sliding ball 100 is a solid spherical member, on which a connecting portion 110 is fixedly arranged for connecting with an external member. The second sliding ball 200 includes a first cavity 210 whose inner surface is a spherical surface. The first sliding ball 100 is rotatably arranged in the first cavity 210 and fits with the inner surface of the first cavity 210. The first sliding ball 100 Can slide along the inner surface of the first cavity 210, compared with the cross joint in the prior art, the spherical contact provides a larger contact area for the movement between the first sliding ball 100 and the second sliding ball 200 , thereby increasing the carrying capacity. The ball seat 300 includes a second cavity 310 with a spherical inner surface, the second sliding ball 200 is rotatably disposed in the second cavity 310 , and the second sliding ball 200 can slide along the inner surface of the second cavity 310 . The gland 400 is fixedly installed on the ball seat 300, and the gland fixes the first sliding ball 100 and the second sliding ball 200 in the second cavity 310, so as to maintain the stability of the joint and prevent the first sliding ball 100 and the second sliding ball from 200 and tee 300 are disengaged from each other.

For convenience of description, the following definitions are now made: on the first sliding ball 100, the end away from the connecting portion 110 is the top of the first sliding ball, and the outer surface of the first sliding ball 100 walks around the top of the first sliding ball along its diameter. The line is the meridian of the first sliding ball 100; the line that goes around the bottom of the first cavity 210 along its diameter on the first cavity 210 is the meridian of the first cavity 210; One end is the top of the second sliding ball, and the line that goes around the top of the second sliding ball along its diameter on the outer surface of the second sliding ball 200 is the warp of the second sliding ball 200, and goes around the second sliding ball along its diameter on the second cavity 310. The line at the bottom of the cavity 310 is the warp of the second cavity 310; thus the latitude of the first sliding ball, the second sliding ball, the first cavity and the second cavity can be obtained through the law of the latitude and longitude of the sphere.

A first limiting structure is arranged between the first sliding ball 100 and the second sliding ball 200, which is used to limit the rotational movement of the first sliding ball 100 relative to the second sliding ball 200 along the parallel direction of the first sliding ball 100, so that There are corresponding constraints on the rotational movement in this direction, which solves the problem of underactuation of the ball hinge joint in this direction in the prior art. The first limiting structure includes a first limiting body 120 and a first limiting groove 220 that are fitted together, and the first limiting body 120 can slide in the first limiting groove 220 . A second limiting structure is provided between the second sliding ball 200 and the ball seat 300, which is used to limit the rotation of the second sliding ball 200 relative to the ball seat 300 along the latitude direction of the second sliding ball 200, so that the rotation in this direction There are corresponding constraints on the movement, which solves the problem of underactuation of the ball hinge joint in this direction in the prior art. The second limiting structure includes a second limiting body 230 and a second limiting groove 320 that are fitted together, and the second limiting body 230 can slide in the second limiting groove 320 .

In this embodiment, the first limiting groove 220 is a rectangular groove arranged on the inner surface of the first cavity 210 and recessed inward. The first limiting groove 220 is arranged along the meridian direction of the first cavity 210. The first limiting body 120 is a rectangular rib that is arranged on the outer surface of the first sliding ball 100 and protrudes outward. The first limiting body 120 is arranged along the meridian of the first sliding ball 100, so that the first limiting body 120 is positioned on the first sliding ball. The extending direction on the 100 is consistent with the extending direction of the first limiting groove 220 in the first cavity 210, when the first sliding ball 100 is installed in the first cavity 210, the first limiting body 120 is located in the first limiting groove 220 and can slide along the first limiting groove 220, the cooperation of the first limiting body 120 and the first limiting groove 220 is the cooperation of a rectangular edge and a rectangular groove, which helps to prevent the first limiting body 120 from the first limiting Slip in bit groove 220.

The second limiting groove 320 is a rectangular groove arranged on the inner surface of the second cavity 310 and recessed inward. The second limiting groove 320 is arranged along the meridian of the second cavity 310. The second limiting body 230 is arranged on the second On the outer surface of the sliding ball 200 and outwardly protruding rectangular ribs, the second limiting body 230 is arranged along the warp of the second sliding ball 200, so that the extending direction of the second limiting body 230 on the second sliding ball 200 is the same as The extension direction of the second limiting groove 320 in the second cavity 310 is the same. When the second sliding ball 200 is installed in the second cavity 310, the second limiting body 230 is located in the second limiting groove 320 and can move along the second The limit slot slides. The cooperation between the second limiting body 230 and the second limiting groove 320 is a combination of a rectangular edge and a rectangular groove, which helps to prevent the second limiting body 230 from slipping out of the second limiting groove 320 . The first sliding ball 100 can rotate relative to the second sliding ball 200 along the extension direction of the first limiting body 120 and the first limiting groove 220 , and the second sliding ball 200 can rotate relative to the ball seat 300 along the second limiting body 230 Rotate with the extending direction of the second limiting groove 320, on the second sliding ball 200, the first limiting groove 220 and the second limiting body 230 form a space cross, so that the rotating direction of the first sliding ball 100 is the same as that of the second sliding ball 200. The rotation directions of the ball 200 intersect, and the combination of the two rotations can realize universal rotation.

During specific implementation, the first limiting body can also be a rectangular rib arranged on the inner surface of the first cavity 210 and protruding outward, which is arranged along the meridian of the first cavity. Correspondingly, the first limiting groove is set at the second The outer surface of a sliding ball 100 is an inwardly recessed rectangular groove, which is arranged along the meridian of the first sliding ball. When the first sliding ball 100 is installed in the first cavity 210, the first limiting body is located in the first limiting groove inside, and can slide along the first limiting slot. The second limiting body can also be arranged on the inner surface of the second cavity 310 and protrude outwards, and it is arranged along the meridian of the second cavity 310. Correspondingly, the second limiting groove is arranged on the second sliding ball 200. The outer surface and inwardly recessed rectangular groove are arranged along the meridian of the second sliding ball. When the second sliding ball 200 is installed in the second cavity 310, the second limiting body is located in the second limiting groove and can move along the second sliding ball. The two limit slots slide. The second limiting body on the second sliding ball 200 intersects with the first limiting groove in a spatial cross.

In this embodiment, the second sliding ball 200 is hemispherical, including two hemispherical shells 201, and each hemispherical shell 201 includes a mounting edge 202, and the two hemispherical shells 201 are detachably fixedly connected by the mounting edge 202, thereby forming a second sliding ball. The sliding ball 200 and the two mounting edges 202 together form the second limiting body 230 . Coordinated positioning pins and positioning holes can be provided between the two mounting edges 202, and are fixedly connected by bolts.

The ball seat 300 is hemispherical as a whole, the second cavity 310 is a hemispherical cavity, the gland 400 is a ring structure, the gland 400 is fixedly installed on the upper part of the ball seat 300, and the gland 400 is provided with a ball for the first sliding ball. 100 passes through the through hole 410, the inner wall of the through hole 410 is a spherical structure with a diameter consistent with the diameter of the inner surface of the second chamber 310, and a pair of relief grooves are also provided on the gland 400 corresponding to the position of the second limiting groove 320 420 , the second limiting body can slide in the relief groove 420 . When the gland 400 is installed on the ball seat 300, the inner surface of the through hole 410 is aligned with the inner surface of the second cavity 310, thereby forming a mounting spherical surface larger than a hemisphere, so that the second sliding ball 200 can slide in the mounting spherical surface, but Can't pull it off. The relief groove 420 is aligned with the second limiting groove 320 to avoid interference between the second limiting body 230 and the gland 400 when the second sliding ball 200 rotates.

The connecting part 110 includes a first connecting pad 111 , the ball seat 300 includes a second connecting pad 330 , and the first connecting pad 111 and the second connecting pad 330 are used for connecting with external components. The structure of the first connection plate 111 and the geothermal connection plate 340 are the same, which can shorten the machining cycle, reduce the cost, and improve the assembly efficiency and assembly tolerance rate of the connection between the high-load universal joint and the external component.

The present invention arranges the second sliding ball 200 between the first sliding ball 100 and the ball seat 300, which ensures the contact area between the first sliding ball 100 and the second sliding ball 200, the second sliding ball 200 and the ball seat 300 The contact area between them improves the load capacity, so that the universal joint of the present invention realizes high load capacity, and a first limit structure and a second limit structure are set to respectively control the rotation of the first sliding ball 100 around its latitude and the rotation of the second sliding ball 100. The rotation of the 200 around its latitude is restricted, so that the movement between the first sliding ball 100 and the second sliding ball 200 and the combination between the second sliding ball 200 and the ball seat 300 realize the universal rotation. The problem of underactuation of ordinary ball twists is solved.

Embodiment two:

Fig. 3 is a schematic structural diagram of an embodiment of the manipulator joint of the present invention. Referring to Fig. 3, the manipulator joint 1 of this embodiment includes a joint body 10 and a universal joint 20, and the universal joint 20 in this embodiment is the first embodiment described above. The high-load-bearing universal joint is beneficial to improve the load-bearing capacity of the mechanical arm joint, wherein the connecting part includes the first connecting plate 111, the ball seat includes the second connecting plate 330, and the joint body 10 is connected with the first connecting plate 111 or the second connecting plate 111. The connecting pad 330 is fixedly connected. The first connecting plate 111 and the second connecting plate 330 have the same structure, which can shorten the machining cycle and reduce the cost, and can be installed with any one of them when installing the condyle body 10 without considering the installation sequence, which is conducive to improving assembly efficiency and fault tolerance . The joint body 10 is symmetrically arranged, and its two ends are installation ends 101 , and the structural settings of the two installation ends 101 are also the same, which is beneficial to realize the modular installation between the mechanical arm joints 1 .

Embodiment three:

Fig. 4 is a schematic structural view of an embodiment of the flexible robotic arm of the present invention. With reference to Fig. 4, the flexible robotic arm of this embodiment includes a driving device and a plurality of mechanical arm joints 1, and the mechanical arm joints 1 are sequentially connected to form a long strip, and the driving device includes Several driving ropes 2, the ends of the driving ropes 2 are fixedly connected to the installation end 101 of the mechanical arm joint, and the installation end 101 is also provided with a perforation 102 for passing the driving rope 2, and each installation end 101 is fixedly connected to three driving ropes 2. The joints 1 of the mechanical arm are respectively driven to move around the universal joint 20 through the driving rope 2, so as to realize the bending action of the flexible mechanical arm as a whole. During specific implementation, the joints of the robotic arm are the joints of the robotic arm described in the second embodiment above, which can improve the assembly efficiency and fault tolerance rate of the flexible robotic arm as a whole, and realize the modularization of the flexible robotic arm. From the description of the first embodiment above, it can be known that the universal joint 20 has the characteristics of high load capacity and accurate control, which can improve the overall load capacity and control accuracy of the flexible manipulator.

The above are only preferred embodiments of the present invention, but the present invention is not limited to the embodiments. Those skilled in the art can also make various equivalent deformations or replacements without violating the spirit of the present invention. These equivalent Any modification or substitution is within the scope defined by the claims of the present application.

Claims (10)

1. A high-bearing universal joint is characterized in that: including first sliding ball, second sliding ball, ball seat and gland, wherein:

The first sliding ball is fixedly provided with a connecting part;

The second sliding ball comprises a first cavity with a spherical inner surface, the first sliding ball is rotatably arranged in the first cavity, and the first sliding ball can slide along the inner surface of the first cavity;

the ball seat comprises a second cavity with a spherical inner surface, the second sliding ball is rotatably arranged in the second cavity, and the second sliding ball can slide along the inner surface of the second cavity;

The gland is fixedly arranged on the ball seat and fixes the first sliding ball and the second sliding ball in the second cavity;

the first sliding ball and the second sliding ball are provided with a first limiting structure therebetween for limiting the rotary motion of the first sliding ball along the weft direction thereof, and the second sliding ball and the ball seat are provided with a second limiting structure therebetween for limiting the rotary motion of the second sliding ball along the weft direction thereof.

2. the high load bearing universal joint of claim 1, wherein: the first limiting structure comprises a first limiting body and a first limiting groove which are installed in a matched mode, the first limiting body can slide in the first limiting groove, the second limiting structure comprises a second limiting body and a second limiting groove which are installed in a matched mode, and the second limiting body can slide in the second limiting groove.

3. the high load bearing universal joint of claim 2, wherein: the first limiting groove is arranged on the inner surface of the first cavity and is inwards concave, the first limiting groove is arranged along the warp of the first cavity, the first limiting body is arranged on the outer surface of the first sliding ball and is outwards convex, the first limiting body is arranged along the warp of the first sliding ball, and the first sliding ball is arranged in the first cavity and is positioned in the first limiting groove.

4. the high load bearing universal joint of claim 3, wherein: the second limiting groove is formed in the inner surface of the second cavity and is inwards concave, the second limiting groove is formed along the weft of the second cavity, the second limiting body is arranged on the outer surface of the second sliding ball and is outwards convex, the second limiting body is arranged along the warp of the second sliding ball, when the second sliding ball is installed in the second cavity, the second limiting body is located in the second limiting groove, and the first limiting groove and the second limiting body are crossed in space.

5. The high load bearing universal joint according to claim 3 or 4, wherein: the second sliding ball is hemispherical and comprises two hemispherical shells, and one hemispherical shell is detachably and fixedly connected with the other hemispherical shell.

6. The high load bearing universal joint of claim 5, wherein: the hemispherical shell comprises mounting edges, the two hemispherical shells are fixedly connected through the mounting edges to form the second sliding ball, and the two mounting edges jointly form the second limiting body.

7. the high load bearing universal joint of claim 6, wherein: the ball seat is wholly hemispherical, the second cavity is a hemispherical cavity, the gland is fixedly installed at the upper part of the ball seat, a through hole for the first sliding ball to pass through is formed in the gland, and the inner wall of the through hole is a spherical surface with the diameter identical to that of the inner surface of the second cavity.

8. the high load bearing universal joint of claim 7, wherein: the position of the pressing cover corresponding to the second limiting groove is further provided with a pair of abdicating grooves, and the second limiting body can slide in the abdicating grooves.

9. The mechanical arm condyle is characterized in that: the high-bearing universal joint comprises a joint body and the high-bearing universal joint as claimed in any one of claims 1 to 8, wherein the joint body is fixedly connected with the connecting part or the ball seat.

10. A flexible robotic arm, comprising: the mechanical arm joint comprises a plurality of mechanical arm joints of claim 9 and a driving device, wherein the mechanical arm joints are connected in sequence, and the driving device is used for driving the mechanical arm joints to move around the high-bearing universal joint.