CN218018581U

CN218018581U - Clamping jaw mechanism and mechanical arm

Info

Publication number: CN218018581U
Application number: CN202220909192.8U
Authority: CN
Inventors: 郭文平; 向迪昀; 孙国康
Original assignee: Beijing Xiaomi Mobile Software Co Ltd
Current assignee: Beijing Xiaomi Robot Technology Co ltd
Priority date: 2022-04-19
Filing date: 2022-04-19
Publication date: 2022-12-13
Anticipated expiration: 2032-04-19

Abstract

The present disclosure provides a clamping jaw mechanism and a mechanical arm. The clamping jaw mechanism adopts a semi-direct-drive joint, and the output capacity of a motor of the semi-direct-drive joint is beneficial to reducing the reduction ratio of the speed reducer, so that the hardware cost is reduced. The semi-direct-drive joint is matched with the transmission mode of the worm gear, so that a first-stage reduction ratio can be added to a transmission assembly of the clamping jaw mechanism, the expected reduction ratio and the expected output torque can be realized at low cost, and the rated closing speed of the clamping jaw can be increased. The structure arrangement enables the clamping jaw mechanism and the mechanical arm using the clamping jaw mechanism to obtain better dynamic performance under the condition of low cost.

Description

Clamping jaw mechanism and mechanical arm

Technical Field

The disclosure relates to the technical field of mechanical arms, in particular to a clamping jaw mechanism and a mechanical arm.

Background

In the related art, the gripper mechanism of the robot arm needs to drive the gripper to move through the motor-driven gear box to realize the corresponding clamping action. Wherein, because the output capacity of the motor is generally less than 0.2Nm level, a high reduction ratio gear box generally above 100 speed ratio needs to be matched to obtain proper output torque, so that the problems of high hardware cost, poor dynamic performance and the like are caused. In addition, motor size and jaw morphology also affect the axial compactness and inertia of the robot arm.

SUMMERY OF THE UTILITY MODEL

The present disclosure provides an improved clamping jaw mechanism and a mechanical arm, so that the clamping jaw mechanism and the mechanical arm using the clamping jaw mechanism can obtain better dynamic performance under the condition of low cost.

A first aspect of the present disclosure provides a gripper mechanism for a robot arm, the gripper mechanism comprising:

a semi-direct drive joint;

the clamping jaw assembly comprises a transmission assembly and a clamping jaw moving body; the transmission assembly comprises a transmission shaft, a worm and a worm wheel in transmission fit with the worm; one of the worm wheel and the worm is in transmission connection with the semi-direct-drive joint, and the other of the worm wheel and the worm is assembled on the transmission shaft so as to drive the transmission shaft to rotate; the clamping jaw moving body is assembled on the transmission shaft so as to move along with the transmission shaft along a preset track.

Optionally, the half direct-drive joint includes a motion output end, and the worm is fixedly connected to the motion output end.

Optionally, the worm includes a transmission main body and a connection flange integrated with the transmission main body, and the connection flange is fixedly connected with the motion output end.

Optionally, the worm wheel is provided with an assembly hole, and the transmission shaft is arranged in the assembly hole in a penetrating manner; the side wall which is enclosed to form the assembling hole is provided with a first bonding structure, the transmission shaft is provided with a second bonding structure, and the first bonding structure and the second bonding structure are limited and fixed.

Optionally, the transmission assembly includes a shaft sleeve, a bearing and a pair of shafting supports; the worm wheel is fixedly assembled on the transmission shaft, and the shafting supports are respectively arranged on two sides of the worm wheel; the bearing is assembled on the shafting support and matched with the transmission shaft; the shaft sleeve is sleeved on the transmission shaft and is positioned between the shafting support and the worm wheel.

Optionally, the clamping jaw mechanism comprises a base flange and a clamping jaw base, the semi-direct-drive joint comprises a bottom static end and a top static end which are oppositely arranged, the bottom static end is fixedly connected with the base flange, and the top static end is fixedly connected with the clamping jaw base; the clamping jaw assembly is assembled on the clamping jaw base.

Optionally, the clamping jaw assembly further comprises a clamping jaw static body and at least one clamping jaw cover, the clamping jaw cover and the clamping jaw static body are matched to enclose a coating space, and the transmission assembly is contained in the coating space.

Optionally, the clamping jaw moving body comprises at least one moving end supporting surface, and the clamping jaw static body is provided with a static end supporting surface corresponding to the moving end supporting surface.

Optionally, the clamping jaw mechanism includes a clamping jaw base fixedly connected with the semi-direct-drive joint, and the clamping jaw stationary body and the clamping jaw cover are fixedly connected to the clamping jaw base.

According to a second aspect of the present disclosure there is provided a robot arm comprising a wrist mechanism and any of the gripper mechanisms of the first aspect, the gripper mechanism being assembled to the wrist mechanism.

The technical scheme provided by the disclosure can at least achieve the following beneficial effects:

the clamping jaw mechanism disclosed by the invention adopts the semi-direct-drive joint, and the motor output capacity of the semi-direct-drive joint is beneficial to reducing the speed reduction ratio of the speed reducer, so that the hardware cost is reduced. The transmission mode that the semi-direct-drive joint is matched with the worm gear can increase a first-level reduction ratio for the transmission assembly of the clamping jaw mechanism, is favorable for realizing the expected reduction ratio and the expected output torque at low cost, and can also improve the rated closing speed of the clamping jaw. The structure arrangement enables the clamping jaw mechanism and the mechanical arm using the clamping jaw mechanism to obtain better dynamic performance under the condition of low cost.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

FIG. 1 is a cross-sectional schematic view of a jaw mechanism in an exemplary embodiment of the present disclosure;

FIG. 2 is a cross-sectional schematic view of a jaw mechanism in another exemplary embodiment of the present disclosure;

FIG. 3 is a cross-sectional structural schematic view of a jaw mechanism in yet another exemplary embodiment of the present disclosure;

FIG. 4 is a perspective view of a jaw mechanism in an open position according to an exemplary embodiment of the present disclosure;

FIG. 5 is a schematic perspective view of another angle of a jaw mechanism in an open position in an exemplary embodiment of the present disclosure;

fig. 6 is a perspective view of a jaw mechanism in a closed state according to an exemplary embodiment of the present disclosure.

Detailed Description

Reference will now be made in detail to the exemplary embodiments, examples of which are illustrated in the accompanying drawings. When the following description refers to the accompanying drawings, like numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the exemplary embodiments below are not intended to represent all implementations consistent with the present disclosure. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present disclosure.

The terminology used in the present disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The use of "first," "second," and similar terms in this disclosure is not intended to indicate any order, quantity, or importance, but rather is used to distinguish one element from another. Similarly, the terms "a" or "an" and the like do not denote a limitation of quantity, but rather denote the presence of at least one, and if only "a" or "an" is denoted individually. "plurality" or "a number" means two or more. Unless otherwise specified, "front", "back", "lower" and/or "upper", "top", "bottom", and the like are for ease of description only and are not limited to one position or one spatial orientation. The word "comprising" or "comprises", and the like, means that the element or item listed as preceding "comprising" or "includes" covers the element or item listed as following "comprising" or "includes" and its equivalents, and does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

In the related art, the gripper mechanism of the robot arm needs to drive the gripper to move through the motor-driven gear box to realize the corresponding clamping action. The output capacity of the motor is generally less than 0.2Nm level, and a high-reduction-ratio gearbox generally above 100 speed ratio needs to be matched to obtain proper output torque, so that the problems of high hardware cost, poor dynamic performance and the like are caused. In addition, motor size and jaw morphology also affect the axial compactness and inertia of the robot arm.

The present disclosure provides a gripper mechanism applied to a robot arm. The clamping jaw mechanism comprises a semi-direct-drive joint and a clamping jaw assembly. The clamping jaw assembly comprises a transmission assembly and a clamping jaw moving body, the transmission assembly comprises a transmission shaft, a worm and a worm wheel in transmission fit with the worm, one of the worm wheel and the worm is in transmission connection with the semi-direct-drive joint, and the other of the worm wheel and the worm is assembled on the transmission shaft so as to drive the transmission shaft to rotate. The clamping jaw moving body is assembled on the transmission shaft so as to generate the motion of a preset track along with the transmission shaft.

The clamping jaw mechanism adopts the semi-direct-drive joint, and the motor output capacity of the semi-direct-drive joint is beneficial to reducing the speed reduction ratio of the speed reducer, so that the hardware cost is reduced. The transmission mode that the semi-direct-drive joint is matched with the worm gear can increase a first-level reduction ratio for the transmission assembly of the clamping jaw mechanism, is favorable for realizing the expected reduction ratio and the expected output torque at low cost, and can also improve the rated closing speed of the clamping jaw. The structure arrangement enables the clamping jaw mechanism and the mechanical arm using the clamping jaw mechanism to obtain better dynamic performance under the condition of low cost.

One of the worm wheel and the worm is in transmission connection with the semi-direct-drive joint, and the other of the worm wheel and the worm is assembled on the transmission shaft so as to drive the transmission shaft to rotate through the worm wheel and the worm. The assembly mode of the worm wheel and the worm in the transmission assembly and the matching mode of the worm wheel and the worm and the semi-direct-drive joint can be set according to specific requirements.

FIG. 1 is a cross-sectional schematic view of a jaw mechanism in an exemplary embodiment of the present disclosure; FIG. 2 is a cross-sectional schematic view of a jaw mechanism in another exemplary embodiment of the present disclosure; fig. 3 is a schematic cross-sectional view of a jaw mechanism in yet another exemplary embodiment of the present disclosure. As shown in fig. 1-3, the gripper mechanism 1 includes a half-direct drive joint 11 and a gripper assembly 12. The clamping jaw assembly 12 comprises a transmission assembly 121 and a clamping jaw moving body 122, the transmission assembly 121 comprises a transmission shaft 1211, a worm 1212 and a worm wheel 1213 in transmission fit with the worm 1212, the worm 1212 is in transmission connection with the half-direct drive joint 11, and the worm wheel 1213 is assembled on the transmission shaft 1211 to drive the transmission shaft 1211 to rotate. The clamping jaw body 122 is assembled to the transmission shaft 1211 to generate a predetermined trajectory along with the transmission shaft 1211.

In the above embodiment, the output capability of the motor of the half direct drive joint 11 is helpful for reducing the reduction ratio of the speed reducer, thereby reducing the hardware cost. The half direct drive joint 11 can increase a first reduction ratio for the transmission assembly 121 of the clamping jaw mechanism 1 by matching with a transmission mode of the worm wheel 1213 and the worm 1212, so that the desired reduction ratio and the desired output torque can be realized at low cost, and the rated closing speed of the clamping jaw can be increased. The structure arrangement enables the clamping jaw mechanism 1 and the mechanical arm using the clamping jaw mechanism 1 to obtain better dynamic performance under the condition of low cost.

In an embodiment, the motor of the half direct drive joint 11 may be an outer rotor motor, the output capacity of the motor is in the 0.5Nm level, the reducer only needs to use a planetary gear box with a single-stage reduction ratio of 6, and simultaneously, due to the adoption of the transmission mode of the worm wheel 1213 and the worm 1212, a reduction ratio of one stage 16 is introduced, so that the reduction ratio of 96 is realized at low cost. In addition, with an external rotor motor of the order of 0.5Nm, a rated output torque of 48Nm can be achieved, so that the rated closing speed of the clamping jaws can reach 0.2m/s. Since the half direct drive joint 11 is generally flat, in some embodiments the axial thickness of the half direct drive joint 11 may be less than or equal to 36.5mm, reducing the axial dimension of the gripper mechanism 1 and facilitating the distribution of inertia of the gripper mechanism 1. The worm gear 1213 and worm 1212 also contribute to the compactness and robustness of the transmission assembly 121. The opening and closing movement of the clamping jaw mechanism 1 is driven by a semi-direct-drive joint 11, the rated output torque of the semi-direct-drive joint 11 can be 3Nm, the peak torque can be 9Nm, the reduction ratio of a mounted single-stage planetary gear box can be 6, and the rated speed is 220rpm.

In some embodiments, half direct drive joint 11 may include a motion output end 111, and worm 1212 is fixedly connected to motion output end 111 to enable connection of worm 1212 to half direct drive joint 11, so as to transmit motion from half direct drive joint 11 to worm 1212. The worm 1212 is conveniently connected with the motion output end 111 of the half direct drive joint 11, so that the convenience of structural improvement is improved.

In the above embodiment, the worm 1212 may include a transmission main body 1212a and a connection flange 1212b integrated with the transmission main body 1212a, where the connection flange 1212b is fixedly connected to the motion output end 111, so as to optimize a connection manner between the worm 1212 and the half direct-drive joint 11, and reduce a space occupied by the connection between the worm 1212 and the half direct-drive joint 11.

In some embodiments, the worm wheel 1213 has an assembly hole 1213a, the transmission shaft 1211 is disposed through the assembly hole 1213a, the sidewall surrounding the assembly hole 1213a has a first key structure 1213b, the transmission shaft 1211 has a second key structure 1211a, and the first key structure 1213b and the second key structure 1211a are fixed in a limited manner. The assembly of the worm wheel 1213 and the transmission shaft 1211 is facilitated by the cooperation of the first and second

key structures

1213b and 1211a, and a reliable coupling effect can be formed between the worm wheel 1213 and the transmission shaft 1211, enabling power transmission between the worm 1212 and the transmission shaft 1211.

In some embodiments, the transmission assembly 121 may include a shaft sleeve 125, a bearing 124, and a pair of shaft supports 123, the worm wheel 1213 is fixedly assembled to the transmission shaft 1211, the shaft supports 123 are respectively disposed at two sides of the worm wheel 1213, the bearing 124 is assembled to the shaft support 123 and is fitted to the transmission shaft 1211, and the shaft sleeve 125 is sleeved on the transmission shaft 1211 and is located between the shaft support 123 and the worm wheel 1213. The structural reliability of the worm wheel 1213 and the transmission shaft 1211 can be improved by the matching of the shafting support 123, the bearing 124, the shaft sleeve 125 and the transmission shaft 1211, so that the transmission effect of the transmission assembly 121 is stable and smooth.

It should be noted that the bearing 124 may be a deep groove ball bearing 124. The integral drive shaft 1211 is supported for free rotational movement within the bearing 124, the bushing 125 is configured to define the axial position of the worm gear 1213 on the drive shaft 1211, the drive shaft 1211 and the worm gear 1213 have corresponding key surface mating structures for transmitting power from the worm gear 1213, and the mating positions of the drive shaft 1211 and the clamping jaw body 122 can be configured with a key surface design similar to the first and second

key structures

1213b and 1211a described above for transmitting power to the clamping jaw body 122.

In some embodiments, as shown in fig. 4-6, the jaw mechanism 1 includes a base flange 13 and a jaw base 14, the half-direct drive joint 11 includes a bottom static end 112 and a top static end 113 that are oppositely disposed, the bottom static end 112 is fixedly connected to the base flange 13, the top static end 113 is fixedly connected to the jaw base 14, and the jaw assembly 12 is assembled to the jaw base 14. The base flange 13 can be fixedly connected with the bottom static end 112 of the half direct-drive joint 11 to provide support and stability guarantee for the driving of the half direct-drive joint 11. The clamping jaw base 14 is fixedly connected with the top static end 113 of the half direct-drive joint 11 to fix the clamping jaw assembly 12 on the half direct-drive joint 11, so that the connection between the clamping jaw assembly 12 and the half direct-drive joint 11 can realize a desired clamping jaw motion track.

In some embodiments, the jaw assembly 12 may further include a jaw static body 126 and at least one jaw cover 127, the jaw cover 127 and the jaw static body 126 cooperate to define a coating space, and the transmission assembly 121 is accommodated in the coating space. The above-mentioned structure makes the transmission assembly 121 be accommodated in the jaw static body 126 and the jaw cover 127, and avoids the transmission assembly 121 from being externally arranged. Adopt above-mentioned clamping jaw assembly 12 to promote the size compactness of clamping jaw, make clamping jaw assembly 12 withstand external impact, use the robustness strong.

In the above embodiment, the movable jaw body 122 may include at least one movable end support surface 1221, and the stationary jaw body 126 may be provided with a stationary end support surface corresponding to the movable end support surface 1221. When the movable clamping jaw body 122 is driven by the half direct drive joint 11 to move, the movable clamping jaw body can be matched with the static end supporting surface to form clamping and releasing actions, so that the flexibility of the clamping actions and the structural integration of the clamping jaw assembly 12 are improved.

Wherein, the clamping jaw moves the main part 122 and can include two and move end holding surface 1221, and two move end holding surface 1221 can be through the fixed concatenation of threaded connection spare in order to form a holding surface, and two move end holding surface 1221 also can be through the fixed concatenation formation of threaded connection spare and be the holding surface of default angle to the form through moving end holding surface 1221 promotes the nimble reliability of getting the operation of pressing from both sides.

In some embodiments, the jaw mechanism 1 may include a jaw base 14 fixedly connected to the half-direct-drive joint 11, and the jaw stationary body 126 and the jaw cover 127 are fixedly connected to the jaw base 14, so as to enclose an appearance surface of the jaw assembly 12 by cooperation of the jaw base 14, the jaw cover 127 and the jaw stationary body 126, thereby improving the integration and aesthetics of the cooperation of the jaw assembly 12 with other parts of the jaw mechanism 1.

The present disclosure further provides a robot arm, the robot arm includes a wrist mechanism and the above-mentioned clamping jaw mechanism 1, the clamping jaw mechanism 1 is assembled to the wrist mechanism.

Because the clamping jaw mechanism 1 adopts the semi-direct-drive joint 11, the output capacity of the motor of the semi-direct-drive joint 11 is beneficial to reducing the speed reduction ratio of the speed reducer, and further the hardware cost is reduced. The half direct drive joint 11 is matched with the worm wheel 1213 and the worm 1212 to increase a first-level reduction ratio for the transmission assembly 121 of the clamping jaw mechanism 1, so that the expected reduction ratio and the expected output torque can be realized at low cost, and the rated closing speed of the clamping jaw can be increased. The structure arrangement enables the clamping jaw mechanism 1 and the mechanical arm using the clamping jaw mechanism 1 to obtain better dynamic performance under the condition of low cost.

By using the half direct drive joint 11 based on the matching of the half direct drive and the single-stage planetary gearbox, the hardware implementation cost is reduced, and the hardware implementation cost of the single-stage planetary gearbox is about 50 percent of that of the multi-stage planetary gearbox. In one embodiment, the opening and closing speed of the whole clamping jaw moving body 122 can be increased by using a high-speed external rotor motor and matching a single-stage planetary gear box with a reduction ratio of 6 with a worm gear 1213 and a worm 1212 with a speed ratio of 16, so that the opening and closing speed of the clamping jaw moving body 122 is greater than or equal to 150 °/s (i.e. 0.2 m/s). Further, by using a single stage planetary gearbox with a 6 reduction ratio and a worm 1213 worm 1212 with a 16 ratio, the overall jaw assembly 12 grip strength is improved, the overall jaw grip torque can be greater than or equal to 48Nm, and the fingertip maximum contact force can be greater than or equal to 615N. Through the semi-direct-drive joint 11 with compact size, the radial size of the whole clamping jaw in the closed posture can be smaller than or equal to 76mm, the axial length can be smaller than or equal to 132mm, and the compactness of the whole structural design of the clamping jaw mechanism 1 and the mechanical arm is improved.

The above description is only exemplary of the present disclosure and should not be taken as limiting the disclosure, as any modification, equivalent replacement, or improvement made within the spirit and principle of the present disclosure should be included in the scope of the present disclosure.

Claims

1. A gripper mechanism, for application to a robotic arm, the gripper mechanism comprising:

a semi-direct drive joint;

2. Gripper mechanism according to claim 1, characterized in that the half direct drive joint comprises a movement output, the worm being fixedly connected to the movement output.

3. Gripper mechanism according to claim 2, characterized in that the worm comprises a transmission body and a connection flange which is integral with the transmission body and is fixedly connected with the motion output.

4. The gripper mechanism of claim 1, wherein the worm gear is provided with an assembly hole, and the transmission shaft is inserted into the assembly hole; the side wall which is enclosed into the assembling hole is provided with a first bonding structure, the transmission shaft is provided with a second bonding structure, and the first bonding structure and the second bonding structure are limited and fixed.

5. The jaw mechanism of claim 1, wherein said drive assembly comprises a shaft sleeve, a bearing, and a pair of shafting mounts; the worm wheel is fixedly assembled on the transmission shaft, and the shafting supports are respectively arranged on two sides of the worm wheel; the bearing is assembled on the shafting support and is matched with the transmission shaft; the shaft sleeve is sleeved on the transmission shaft and is positioned between the shafting support and the worm wheel.

6. The jaw mechanism of claim 1, wherein the jaw mechanism comprises a base flange and a jaw base, the semi-direct drive joint comprises a bottom stationary end and a top stationary end that are oppositely disposed, the bottom stationary end is fixedly connected to the base flange, and the top stationary end is fixedly connected to the jaw base; the clamping jaw assembly is assembled on the clamping jaw base.

7. The jaw mechanism of claim 1, wherein said jaw assembly further comprises a jaw stationary body and at least one jaw cover, said jaw cover and said jaw stationary body cooperate to define a coating space, and said transmission assembly is received in said coating space.

8. The jaw mechanism of claim 7, wherein said movable jaw body includes at least one movable end bearing surface, and said stationary jaw body defines a stationary end bearing surface corresponding to said movable end bearing surface.

9. The jaw mechanism of claim 7, wherein said jaw mechanism comprises a jaw base fixedly connected to said half direct drive joint, said jaw stationary body and said jaw cover being fixedly connected to said jaw base.

10. A robot arm comprising a wrist mechanism and a gripper mechanism according to any of claims 1 to 9, said gripper mechanism being assembled to said wrist mechanism.