A gripper structure

Abstract

The present application relates to a kind of gripper structures, belong to robot technical field, solve the problem that one of the insufficient envelope contact, not enough stable problem of two-finger gripper in prior art when grabbing object.This application includes drive mechanism, transmission mechanism, driving arm, driven arm and claw tip plate;Transmission mechanism is connected with the output end of drive mechanism, claw tip plate is connected to the end of driven arm, for contacting and clamping target object;Driving arm is bent structure, driving arm includes arm body, first end and second end, first end and second end are located at both ends of arm body respectively;First end is rotatably connected on the output end of transmission mechanism;Part of arm body of driving arm is contacted with target object and provides support to it.The present application improves the stability of clamping target object.

Description

Technical Field

[0001] This invention relates to the field of robotics, and more particularly to a gripper structure. Background Technology

[0002] Two-finger grippers are a common type of gripping mechanism in robot end effectors, widely used for grasping, handling, and assembling cylindrical workpieces, block workpieces, and other regular parts. To improve the compactness and environmental adaptability of the overall gripper structure, existing technologies have developed two-finger gripper structures where the rotation fulcrum of the gripper's active arm is located in the base portion, and a transmission mechanism is used to achieve drive output.

[0003] However, in this type of two-finger gripper, the connecting support structure between the gripper's transmission structure and the clamping end directly affects the motion trajectory of the clamping end and its clamping force performance. Currently available connecting supports are typically direct-connection active arms, which can lead to insufficient envelope contact support and inadequate gripping stability, especially when clamping cylindrical objects. Therefore, it is necessary to design a reasonable structure for the connecting support in a two-finger gripper to improve the gripping stability of cylindrical objects. Summary of the Invention

[0004] Based on the above analysis, the present invention aims to provide a gripper structure to solve the problem that existing two-finger grippers are prone to unstable gripping when grasping cylindrical objects.

[0005] This invention is achieved through the following technical solution: A gripper structure includes a drive mechanism, a transmission mechanism, a drive arm, a driven arm, and a gripper tip plate; The transmission mechanism is connected to the output end of the drive mechanism, and the claw tip plate is connected to the end of the driven arm for contacting and clamping the target object; The active arm has a bent structure and includes an arm body, a first end, and a second end, with the first end and the second end located at opposite ends of the arm body; the first end is rotatably connected to the output end of the transmission mechanism. A portion of the active arm contacts and supports the target object.

[0006] Furthermore, it also includes a transmission cabin, through which the transmission mechanism is connected to the drive arm; The active arms are symmetrically arranged, with the axis of symmetry of the symmetrical arrangement of the active arms as the y-axis; let the rotation fulcrums of the two active arms be A1 and A2, with the line connecting A1 and A2 as the x-axis, and the line connecting A1 and A2 forming line segment A1A2, and establish a coordinate system with the midpoint of line segment A1A2 as the origin; the distance between the side of the transmission cabin away from the drive mechanism and the x-axis is H; The arm body comprises a first segment and a second segment; the intersection point of the first segment and the second segment is B, then: y B ≤H; Among them, y B Let B be the ordinate of point B in the coordinate system.

[0007] Furthermore, the arm body includes a first segment and a second segment; when the target object is a cylinder, the contact point between the second segment and the cylinder is located on the second segment.

[0008] Furthermore, the arm body includes a first segment and a second segment, and the intersection point of the first segment and the second segment is B; when the target object is a cylinder, the distance between the contact point of the second segment and the cylinder and point B is:

[0009] in, Let B be the coordinates of the center of the cylinder in the coordinate system described above; let B be the coordinates of point B in the coordinate system described above. The angle between the second segment and the x-axis; It is less than or equal to the length of the second segment.

[0010] Furthermore, it also includes a transmission cabin, through which a portion of the transmission mechanism is connected to the drive arm; The transmission mechanism includes a transmission shaft and a transmission wheel. The transmission shaft is connected to the drive mechanism, and the transmission wheel meshes with the transmission shaft. The transmission shaft and the transmission wheel are disposed in the transmission compartment.

[0011] Furthermore, the transmission mechanism also includes an output shaft, and the transmission wheel is disposed on the output shaft and rotates around the output shaft; And / or, the transmission compartment includes a housing, with both ends of the output shaft extending out of the housing and respectively connected to the paired drive arms.

[0012] Furthermore, the driven boom is symmetrically and rotatably disposed outside the transmission compartment; And / or, it also includes a master-slave connecting rod, through which the driven arm is linked to the driving arm.

[0013] Furthermore, the master-slave connecting rod includes a first part and a second part connected to each other; the first part is rotatably connected to the driven arm, and the second part is rotatably connected to the second end of the master arm.

[0014] Furthermore, the claw tip plate is connected to the second part, and the claw tip plate is linked with the master-slave connecting rod.

[0015] Furthermore, it also includes a sealing ring, which is disposed between the drive mechanism and the transmission compartment.

[0016] Compared with the prior art, the present invention can achieve at least the following beneficial effects: Without changing the relative positions of the two ends of the active arm, this invention improves the active arm from a straight-connected gripper to a bent structure, so that part of the active arm can participate in the gripping as a working contact section when gripping the target object, thereby forming a composite contact and envelope support structure together with the claw tip plate, which improves the gripping stability of the target object.

[0017] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from the description and drawings, which are particularly pointed out. Attached Figure Description

[0018] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. Figure 1 is a schematic diagram of the external structure of the gripper structure provided by the present invention; Figure 2 This is a schematic diagram of the gripper structure for holding a cylinder provided by the present invention; Figure 3 A simplified model diagram of the gripper structure for holding a cylinder provided by the present invention; Figure 4 A schematic diagram of the external structure of the transmission compartment provided by the present invention; Figure 5 This is an exploded structural diagram of the transmission compartment provided by the present invention.

[0019] Figure label: 1-Drive mechanism; 2-Transmission mechanism; 21-Drive shaft; 22-Drive wheel; 23-Output shaft; 24-Bearing; 3-Drive arm; 31-First section; 32-Second section; 4-Driven arm; 5-Claw tip plate; 6-Master-slave connecting rod; 61-First part; 62-Second part; 7-Transmission compartment; 8-Sealing ring; 9-Cylinder. Detailed Implementation

[0020] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of these embodiments and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0021] A specific embodiment of the present invention discloses a gripper structure, such as... Figure 1 As shown, it includes a drive mechanism 1, a transmission mechanism 2, an active arm 3, a driven arm 4, and a claw tip plate 5.

[0022] The transmission mechanism 2 is connected to the output end of the drive mechanism 1. The claw tip plate 5 is connected to the end of the driven arm 4 and is used to contact and clamp the target object.

[0023] The active arm 3 has a bent structure and includes an arm body, a first end and a second end, which are located at the two ends of the arm body respectively; the first end is rotatably connected to the output end of the transmission mechanism 2.

[0024] Part of the active arm 3 contacts the outer peripheral wall of the target object and provides support to it.

[0025] In this embodiment, the active arm 3 is configured as a bent structure, and when the target object is a cylinder 9, part of the arm of the active arm 3 contacts the outer peripheral wall of the cylinder 9 and provides support to it. This allows the active arm 3 and the claw tip plate 5 to contact and support the object being gripped when the gripper is holding the cylinder 9, forming a composite contact and envelope support structure. This transforms the traditional "point contact" or "line contact" into multi-angle contact support, avoiding reliance solely on the claw tip plate 5 for gripping, and improving gripping stability and reliability.

[0026] On the other hand, the active arm 3 itself undertakes the functions of clamping and supporting, without the need for additional special arc-shaped pads or auxiliary support components, which simplifies the overall number of gripper parts and reduces the difficulty of processing and manufacturing and assembly costs.

[0027] It should be noted that the accompanying drawings in this embodiment are illustrated by clamping a cylinder 9, but the objects that the gripper disclosed in this embodiment can clamp are not limited to the cylinder 9.

[0028] For example, the drive mechanism 1 in this embodiment can be a drive motor.

[0029] Furthermore, it also includes a transmission compartment 7, through which the transmission mechanism 2 passes and connects to the drive arm 3. The drive arm 3 is rotatably mounted on the transmission mechanism 2. The transmission compartment 7 is located between the clamped target object and the drive mechanism 1. That is, the drive mechanism 1 is located below the transmission compartment 7. The driven arm 4 is symmetrically and rotatably mounted outside the transmission compartment 7.

[0030] In this embodiment, two pairs of active arms 3 are provided, with two arms in each pair, and the two active arms 3 in each pair are arranged symmetrically. Figure 1 and Figure 2 As shown, in a pair of active arms, either active arm 3 bends away from the other active arm 3. Figure 3As shown, let the rotation fulcrums of the two active arms 3 be A1 and A2 respectively. The line connecting A1 and A2 is the x-axis, and the axis of symmetry of the symmetrical distribution of the active arms 3 is the y-axis. The line connecting A1 and A2 forms line segment A1A2. A coordinate system is established with the midpoint of line segment A1A2 as the origin.

[0031] The following example uses one of the active arms, 3, for reference. Figure 3 The first end of the arm is A1, and the second end is C. Specifically, the arm body includes a first segment 31 and a second segment 32. The intersection point of the first segment 31 and the second segment 32 is B. The length of the first segment 31 is L1, and the length of the second segment 32 is L2. In the established mathematical model, the first segment 31 corresponds to line segment A1B. In the established mathematical model, the second segment 32 corresponds to line segment BC. The first segment 31 transmits the motion at the rotation fulcrum A1 of the active arm 3 to B. The second segment 32 ultimately transmits the power at point B to the claw tip plate 5. The second segment 32 participates in the clamping of the cylinder 9 as a contact segment. Figure 3 The line segment CD in the diagram represents the equivalent model of the claw tip plate 5 and the master-slave connecting rod 6.

[0032] To avoid potential motion collisions when the bent active arm 3 is arranged within a limited space, this embodiment ensures that the connection point B between the first segment A1B and the second segment BC remains below the upper limit of the transmission compartment 7 throughout the entire working range. (Reference) Figure 3 Let H be the distance between the side of the transmission compartment 7 facing away from the drive mechanism 1 and the rotation fulcrum of the drive arm 3. To satisfy the encapsulation boundary constraints of the transmission compartment 7, the ordinate of the inflection point B should satisfy the following within the entire working range: Among them, y B Let be the ordinate of point B.

[0033] This embodiment limits the ordinate of the bending point B to no more than the upper limit H of the transmission compartment 7. Since the area above the transmission compartment 7 is the working clamping area, this ensures that the working surface of the second segment BC can cover this area under any circumstances, guaranteeing the determinacy and stability of the gripper clamping. This is particularly suitable for clamping objects with small radii, such as cylinders 9 with a radius less than 20mm. If the ordinate of point B exceeds the upper limit H, the second segment BC may not be able to contact the cylinder 9, compromising clamping stability.

[0034] refer to Figure 3 Let the first segment A1B rotate at an angle of θ under the action of drive mechanism 1 and transmission mechanism 2. The two opposing active arms 3 rotate simultaneously, causing the claw tip plates 5 to move towards or away from each other, thereby clamping and releasing the cylinder 9.

[0035] Continue to refer to Figure 3In this embodiment, the distance from the rotation fulcrum A1 of the active arm 3 to the endpoint C of the second end is defined as... This distance is the equivalent length in a traditional direct-connection scheme. An angle is formed between the first segment 31 and the second segment 32. To address the issue that simple bending may lead to a loss of clamping range or clamping force, this embodiment maintains... Under the condition that remains unchanged, optimize the length of the first segment AB. The length of the second segment BC and fixed angle This allows the active arm 3 to achieve a better bending shape while maintaining the same total envelope size, thereby improving clamping performance. The coordinates of the rotation fulcrum A1 of the active arm 3 can be expressed as: Specifically, M must be less than half the maximum opening and closing length of the grippers. This ensures that the working surface of the second section BC covers the working clamping area above the transmission compartment 7 under all circumstances, guaranteeing the certainty and stability of the gripper clamping. This is particularly suitable for clamping cylindrical objects with smaller radii, such as cylinders with a radius less than 20mm. If M is greater than half the maximum opening and closing length of the grippers, the second section BC may not be able to contact the cylinder 9, compromising clamping stability.

[0036] At the running angle When the first segment AB ends, the coordinates of endpoint B can be expressed as: The orientation angle of the second segment 32 of the active arm 3, i.e., the angle between the second segment 32 and the x-axis, is defined as: When the target object is a cylinder 9, the second segment 32 of the active arm 3 makes contact with the cylinder 9 to provide auxiliary support.

[0037] Let S be the contact point between the second segment 32 and the cylinder 9. T Then S T Located on the second segment 32. This solves the problem of uncontrollable contact position between the bending active arm 3 and the cylinder 9, which may lead to separation from the effective contact segment, and improves the certainty and stability of clamping.

[0038] Furthermore, the distance between the contact point and point B for:

[0039] in, Let be the coordinates of the center of cylinder 9; Here are the coordinates of point B; The angle between the second segment 32 and the x-axis. In the specific calculation process, the result of subtracting the coordinates of the center of cylinder 9 from the coordinates of point B needs to be converted into a row vector, and then multiplied by the column vector.

[0040] In this embodiment, the above This ensures that the contact point is always within the effective length range of the second segment 32, solving the problem of uncontrollable contact position between the bent active arm 3 and the cylinder 9, which may lead to separation from the effective contact segment. It can guarantee that the bent active arm 3 can achieve working contact with the cylinder 9 through the second segment 32, forming an enveloping support for the cylinder 9, and improving the clamping stability of the cylindrical target object.

[0041] Furthermore, in order to address the shortcomings of existing two-finger grippers in terms of dust and water resistance, such as... Figure 4 and Figure 5 As shown, the transmission mechanism 2 in this embodiment includes a transmission wheel 22 and a transmission shaft 21. The transmission shaft 21 is connected to the drive mechanism 1, and the transmission wheel 22 meshes with the transmission shaft 21. The transmission wheel 22 and the transmission shaft 21 are disposed within the transmission chamber 7. Compared to traditional grippers that use ball bearings and lead screws as the transmission mechanism 2, which have the disadvantage of not being able to house the ball bearings and lead screws inside the transmission chamber 7, i.e., not being able to achieve a seal, this embodiment achieves the gripper opening and closing function while the cavity of the transmission chamber 7 is completely sealed. This reduces the problem of existing two-finger grippers being easily contaminated and corroded by internal transmission components in dusty or humid environments, leading to shortened lifespan and reduced clamping force. It improves the sealing performance and operational reliability of the gripper and extends its service life. In other words, this embodiment can seal the transmission mechanism 2 inside the transmission chamber 7, which is beneficial to extending the service life of the gripper and making its performance more stable.

[0042] like Figure 5 As shown, the transmission mechanism 2 in this embodiment also includes an output shaft 23. The transmission wheel 22 is mounted on the output shaft 23 and rotates around the output shaft 23.

[0043] And / or, the transmission compartment 7 includes a housing, with both ends of the output shaft 23 extending out of the housing and respectively connected to a pair of active arms 3, realizing synchronous drive of the two active arms 3 by a single drive source, reducing the risk of clamping offset or uneven clamping force caused by asynchronous movement of the two active arms 3. The transmission compartment 7 is provided with a bearing mounting part at the position where the output shaft 23 protrudes from the housing of the transmission compartment 7, and a bearing 24 is installed in the bearing mounting part, which is used to provide rotational support for the output shaft 23.

[0044] The bearing 24 and the housing of the transmission compartment 7 are sealed by one or more of the following methods: interference fit, sealant, grease, oil seal, or sealed bearing 24.

[0045] In a preferred embodiment, the number of drive shafts 21 is one and the number of drive wheels 22 is two, which reduces the number of parts, simplifies the overall number of parts in the gripper, and reduces the difficulty of processing and manufacturing and the assembly cost.

[0046] Furthermore, it also includes a sealing ring 8, which is disposed between the drive mechanism 1 and the transmission compartment 7 to seal the connection gap between the drive motor and the housing of the transmission compartment 7, thereby reducing the risk of external moisture or dust seeping into the transmission compartment 7 from the motor mounting interface and improving the sealing performance of the drive-transmission system.

[0047] In this embodiment, the gripper structure further includes a master-slave connecting rod 6. The driven arm 4 is linked to the driving arm 3 via the master-slave connecting rod 6, and the master-slave connecting rod 6 is connected to the claw tip plate 5. This embodiment achieves linkage between the driving arm 3 and the driven arm 4 through the master-slave connecting rod 6, enabling the claw tip plate 5 to obtain a definite motion trajectory under the drive of the driving arm 3. This solves the motion lag or sway problem that may occur when the driven arm 4 passively follows, and improves the coordination and repeatability of the gripping action of the claw tip plate 5.

[0048] Specifically, the master-slave connecting rod 6 includes a first part 61 and a second part 62 connected to each other. The first part 61 is rotatably connected to the driven arm 4, and the second part 62 is rotatably connected to the second end of the master arm 3, thereby converting the swing of the master arm 3 into a planar composite motion of the driven arm 4, making the driven arm 4 move in various postures to adapt to the changes in the contact angle of cylinders 9 of different sizes, and improving the adaptability of the gripper to cylinders 9 of different diameters.

[0049] The claw tip plate 5 is connected to the second part 62 of the master-slave connecting rod 6, and the claw tip plate 5 and the master-slave connecting rod 6 are linked together. In this embodiment, there is no need to set up a separate drive mechanism 1 for the claw tip plate 5, which reduces manufacturing costs and control difficulty.

[0050] During operation, the drive mechanism 1 drives the transmission shaft 21 to rotate, which in turn drives the transmission wheel 22 to rotate. The transmission wheel 22 further drives the output shaft 23 to rotate. The output shaft 23 drives the active arm 3 to swing, and the active arm 3 drives the driven arm 4 to move synchronously via the master-slave connecting rod 6, thereby enabling the claw tip plate 5 to clamp or open. When clamping a target object, the second section 32 of the bent structure of the active arm 3 provides auxiliary support to the target object, making the clamping more stable and reliable.

[0051] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A gripper structure, characterized in that, It includes a drive mechanism (1), a transmission mechanism (2), an active arm (3), a driven arm (4), and a claw tip plate (5); The transmission mechanism (2) is connected to the output end of the drive mechanism (1), and the claw tip plate (5) is connected to the end of the driven arm (4) for contacting and clamping the target object; The active arm (3) is a bent structure. The active arm (3) includes an arm body, a first end and a second end. The first end and the second end are located at the two ends of the arm body, respectively. The first end is rotatably connected to the output end of the transmission mechanism (2). Part of the active arm (3) contacts the target object and provides support to it.

2. The gripper structure according to claim 1, characterized in that, It also includes a transmission compartment (7), through which the transmission mechanism (2) is connected to the active arm (3); The active arms (3) are symmetrically arranged, with the axis of symmetry of the active arms (3) as the y-axis; the rotation fulcrums of the two active arms (3) are A1 and A2 respectively, with the line connecting A1 and A2 as the x-axis, and the line connecting A1 and A2 forming line segment A1A2, with the midpoint of line segment A1A2 as the origin to establish a coordinate system; the distance between the side of the transmission compartment (7) away from the drive mechanism (1) and the x-axis is H; The arm body includes a first segment (31) and a second segment (32); the intersection point of the first segment (31) and the second segment (32) is B, then: y B ≤H; Among them, y B Let B be the ordinate of point B in the coordinate system.

3. The gripper structure according to claim 1, characterized in that, The arm body includes a first segment (31) and a second segment (32); when the target object is a cylinder (9), the contact point between the second segment (32) and the cylinder (9) is located on the second segment (32).

4. The gripper structure according to claim 2, characterized in that, The arm body includes a first segment (31) and a second segment (32), and the intersection point of the first segment (31) and the second segment (32) is B; when the target object is a cylinder (9), the distance between the contact point of the second segment (32) and the cylinder (9) and point B is: in, Let B be the coordinates of the center of the cylinder (9) in the coordinate system; let B be the coordinates of point B in the coordinate system. The angle between the second segment (32) and the x-axis; The length is less than or equal to the length of the second segment (32).

5. The gripper structure according to claim 1, characterized in that, It also includes a transmission compartment (7), through which part of the transmission mechanism (2) is connected to the drive arm (3); The transmission mechanism (2) includes a transmission shaft (21) and a transmission wheel (22). The transmission shaft (21) is connected to the drive mechanism (1), and the transmission wheel (22) meshes with the transmission shaft (21). The transmission shaft (21) and the transmission wheel (22) are disposed in the transmission compartment (7).

6. The gripper structure according to claim 5, characterized in that, The transmission mechanism (2) further includes an output shaft (23), and the transmission wheel (22) is disposed on the output shaft (23) and rotates around the output shaft (23); And / or, the transmission compartment (7) includes a housing, with both ends of the output shaft (23) extending out of the housing and respectively connected to the paired drive arms (3).

7. The gripper structure according to claim 2, characterized in that, The driven arm (4) is symmetrically and rotatably disposed outside the transmission compartment (7); And / or, it also includes a master-slave connecting rod (6), through which the driven arm (4) is linked to the driving arm (3).

8. The gripper structure according to claim 7, characterized in that, The master-slave connecting rod (6) includes a first part (61) and a second part (62) connected to each other; the first part (61) is rotatably connected to the slave arm (4), and the second part (62) is rotatably connected to the second end of the master arm (3).

9. The gripper structure according to claim 8, characterized in that, The claw tip plate (5) is connected to the second part (62), and the claw tip plate (5) is linked with the master-slave connecting rod (6).

10. The gripper structure according to claim 2, characterized in that, It also includes a sealing ring (8), which is disposed between the drive mechanism (1) and the transmission compartment (7).

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