CN111993395A

CN111993395A - Terminal gesture self-sustaining device of arm

Info

Publication number: CN111993395A
Application number: CN202010829660.6A
Authority: CN
Inventors: 喻依茗
Original assignee: Hangzhou Jieming Intelligent Equipment Co ltd
Current assignee: Hangzhou Jieming Intelligent Equipment Co ltd
Priority date: 2020-08-18
Filing date: 2020-08-18
Publication date: 2020-11-27

Abstract

The invention belongs to the technical field of industrial mechanical arms. The technical scheme is as follows: a terminal attitude self-holding device of a mechanical arm comprises a large arm motor, a large arm rod piece, a small arm rod piece, a terminal shaft and a terminal platform, wherein the large arm motor is installed on a rack; the method is characterized in that: the mechanical arm further comprises a first driving wheel which is coaxially arranged with a motor shaft of the large arm, a wheel connecting shaft which is rotatably inserted and positioned in an inner cavity of the arm connecting shaft, two ends of the wheel connecting shaft extend out of the inner cavity and then are respectively fixed with the second driving wheel and the third driving wheel, a fourth driving wheel which is arranged on the terminal shaft, a first driving belt and a second driving belt. The device can automatically keep the mechanical arm terminal in the initial posture for any rotation angle of each joint under the condition of not limiting the movement range of the mechanical arm joint, and has no dead point.

Description

Terminal gesture self-sustaining device of arm

Technical Field

The invention belongs to the technical field of industrial mechanical arms, and particularly relates to a self-holding device for a terminal posture of a mechanical arm.

Background

With the development of science and technology and the continuous improvement of labor cost, the application of the robot in various industries is more and more extensive, the application of the robot reduces the labor intensity of people, improves the production efficiency and enhances the core competitiveness of enterprises.

At present, most of operation mechanical arms basically have 6 degrees of freedom, the coordinate position of a control terminal of 3 degrees of freedom, and the pointing posture of the control terminal of 3 degrees of freedom of a wrist joint. However, in many working occasions such as sorting, stacking, filling, labeling and the like, the operation of the operation mechanical arm is on a definite plane such as a conveying belt, a workbench or the ground, and the spatial relationship between the plane and the operation mechanical arm is fixed and invariable. The mechanical arm operates the objects on the planes, and actually, the requirements can be met only by 4 degrees of freedom, so that the complexity and the cost of the mechanical arm can be greatly reduced by omitting two degrees of freedom.

Aiming at the scene, the SCARA mechanical arm changes the motion plane of the large arm and the small arm of the mechanical arm from the rotation vertical to the ground to the rotation parallel to the ground on the basis of the PUMA mechanical arm, and the third degree of freedom is changed into the translation structure vertical to the ground, so that the terminal device can always point to the ground. However, the effective load of the SCARA mechanical arm is greatly reduced, and the space utilization in the height direction is insufficient; therefore, the arrangement density of the SCARA mechanical arms on the horizontal layer is not high enough, and high coordination control is needed among machines, otherwise, the mutual interference and collision of the mechanical arms are caused.

Another solution is to add a terminal attitude self-holding mechanism. The terminal gesture self-holding mechanisms adopted at present are two groups of four-bar mechanisms which are respectively arranged on the large arm and the small arm so as to keep the stable terminal gesture of the mechanical arm. Because the four-bar mechanism has dead points, the rotation angle of the large arm and the small arm is required to be not more than 180 degrees, which limits the motion range of the mechanical arm and reduces the flexibility of the mechanical arm.

Disclosure of Invention

The present invention is to overcome the above-mentioned shortcomings in the background art, and provide a robot terminal posture self-holding device, which can automatically hold the robot terminal in the initial posture without dead point for any rotation angle of each joint under the condition of not limiting the range of motion of the robot joint.

In order to achieve the purpose, the invention provides the following technical scheme:

a terminal attitude self-holding device of a mechanical arm comprises a large arm motor, a large arm rod piece, a small arm rod piece, a terminal shaft and a terminal platform, wherein the large arm motor is installed on a rack; the method is characterized in that: the mechanical arm further comprises a first driving wheel which is fixed on a large arm motor flange or a large arm motor base and is coaxially arranged with a large arm motor shaft, a wheel connecting shaft which is rotatably inserted and positioned in an inner cavity of the arm connecting shaft, and two ends of the wheel connecting shaft extend out of the inner cavity and are respectively fixed with a second driving wheel and a third driving wheel, a fourth driving wheel which is arranged on the terminal shaft, a first driving belt which is meshed and matched with the first driving wheel and the second driving wheel simultaneously, and a second driving belt which is meshed and matched with the third driving wheel and the fourth driving wheel simultaneously.

The large arm motor shaft, the arm connecting shaft and the terminal shaft are arranged in parallel.

The first driving wheel is sleeved on the large arm motor shaft in a penetrating manner through a center hole of the first driving wheel.

And the fourth driving wheel is sleeved and fixed on the terminal shaft.

The first transmission wheel and the second transmission wheel have the same outer diameter and tooth number and are meshed and connected through a first transmission belt.

The third driving wheel and the fourth driving wheel have the same outer diameter and tooth number and are meshed and connected by a second driving belt.

The first transmission wheel to the fourth transmission wheel are all synchronous wheels or chain wheels, and the first transmission belt and the second transmission belt are synchronous belts matched with the synchronous wheels or chains matched with the chain wheels.

Furthermore, the small arm rod piece is fixed with the arm connecting shaft; a small arm motor is arranged at the tail end of the large arm rod piece, and a driving screw rod is fixed on a motor shaft of the small arm; a driven gear engaged with the driving screw is fixed on the arm connecting shaft.

Compared with the prior art, the invention has the following beneficial effects: the range of joint motion of the mechanical arm is not limited; the mechanical arm terminal can be automatically kept at the initial posture for any rotation angle of 0-360 degrees of each joint, and no dead point exists; the invention can be extended to mechanical arms with more joints and is used for self-holding the terminal posture.

Drawings

Fig. 1 is a schematic front view of embodiment 1 of the present invention.

Fig. 2 is one of the schematic views of the operating states of the boom and the sprocket in embodiment 1 of the present invention.

FIG. 3 is a second schematic view showing the operation states of the boom and the sprocket in embodiment 1 of the present invention.

Fig. 4 is an exploded view of the arm link and the wheel link in embodiment 1 of the present invention.

Fig. 5 is one of the schematic views of the operation states of the arm and the sprocket in embodiment 1 of the present invention.

Fig. 6 is a second schematic view showing the operation state of the arm and the sprocket in embodiment 1 of the present invention.

Fig. 7 is a schematic view of a connection relationship between the upper arm and the lower arm in embodiment 2 of the present invention.

Fig. 8 is an enlarged structural diagram in the left-view direction of fig. 7.

Description of reference numerals:

1-large arm motor; 2-large arm rod member; 3-small arm rod piece; 4-a terminal shaft; 5-a terminal platform; 6-a first drive wheel; 7-arm connecting shaft; 8-a second transmission wheel; 9-a third driving wheel; 10-wheel connecting shaft; 11-a fourth transmission wheel; 12 — a first drive belt; 13-second drive belt.

Detailed Description

The invention will be described in further detail below with reference to an embodiment shown in the drawings.

Embodiment 1 as shown in fig. 1, 2, 3, 4, 5, and 6, in addition to the large arm motor 1, the large arm rod 2, the small arm rod 3, the terminal shaft 4, and the terminal platform 5 which are mounted on the frame through the large arm motor base, the terminal attitude self-holding device of the robot arm provided in this embodiment further includes a first driving pulley 6, an arm connecting shaft 7, a second driving pulley 8, a third driving pulley 9, a wheel connecting shaft 10, a fourth driving pulley 11, a first driving belt 12, and a second driving belt 14.

The center hole of the first driving wheel is rotatably sleeved on the large arm motor shaft and is fixedly connected to the flange surface of the large arm motor or the large arm motor base; as the boom motor shaft rotates, the first drive pulley remains stationary, which provides a reference point for the entire robot arm, or initial attitude of the terminal platform.

The first driving wheel is tightly attached to the large arm motor and can be regarded as a whole with the large arm motor, so that the introduction of the first driving wheel does not interfere with the rotation of the large arm rod piece, and the starting end of the large arm rod piece is fixed on a large arm motor shaft and can rotate in an unconstrained manner by 360 degrees under the driving of the large arm motor. The central hole of the second driving wheel 8 is rotatablely sleeved on the arm connecting shaft 7 and is meshed and connected with the first driving wheel 6 by a first driving belt 12; since the first driving wheel is stationary and the first driving belt does not rotate, when the large arm lever rotates, the second driving wheel will rotate relative to the arm link under the restriction of the first driving belt (as shown in fig. 2 and 3; in order to show the rotation of the synchronizing wheel, a mark point is added to the second driving wheel in the figure).

The first driving wheel and the second driving wheel have the same outer diameter and tooth number and are tightly meshed and connected by the first driving belt, so that the rotating angle of the second driving wheel relative to the arm connecting shaft is the same as that of the large arm rod piece, but the rotating angles are opposite in direction; and when the large arm motor is used as a reference point, the pointing direction of the mark point of the second driving wheel is always unchanged no matter what angle the large arm rod piece rotates.

The arm connecting shaft is a hollow shaft which can rotate relative to the large arm rod piece, and the starting end of the small arm rod piece is sleeved and fixed on the arm connecting shaft to realize the hinge joint with the tail end of the large arm rod piece; the wheel connecting shaft 10 is rotatably arranged in a cavity of the arm connecting shaft (the outer diameter of the wheel connecting shaft is smaller than the inner diameter of the arm connecting shaft), and two ends of the wheel connecting shaft respectively extend out of the end faces of two ends of the arm connecting shaft; the second driving wheel and the third driving wheel are sleeved on the wheel connecting shaft through respective central holes and are respectively and fixedly connected to two ends of the wheel connecting shaft (as shown in figure 4; positioned by virtue of steps of the wheel connecting shaft), and both the second driving wheel and the third driving wheel can rotate relative to the arm connecting shaft.

Since the second driving wheel, the third driving wheel and the wheel connecting shaft are fixedly connected and can be seen as a whole, the rotation angle of the third driving wheel relative to the arm connecting shaft is completely consistent with the rotation angle of the second driving wheel relative to the arm connecting shaft, so that the index point direction of the third driving wheel is always unchanged (as shown in fig. 5; in order to illustrate the rotation condition of the synchronous wheel, an index point is added to the third driving wheel in fig. 5 and 6. since the section view angle of fig. 5 and 6 is opposite to that of fig. 3, the index point of the third driving wheel in fig. 5 and 6 is shown as a horizontal mirror image point of the index point of the second driving wheel in fig. 3).

The central hole of the fourth driving wheel is fixedly connected to the rotatable terminal shaft; when the small arm rod piece rotates, the fourth transmission wheel and the terminal shaft rotate relative to the small arm (as shown in fig. 6); since the third driving wheel and the fourth driving wheel have the same outer diameter and teeth number and are tightly meshed and connected by the second driving belt 12, the rotation angle of the fourth driving wheel relative to the small arm is the same as the rotation angle of the small arm rod piece, but the rotation angle is opposite in direction.

The terminal platform is fixed on the terminal shaft and is integrated with the fourth transmission wheel, so that the posture of the terminal platform is always kept unchanged.

The third driving wheel, the fourth driving wheel and the second driving belt are arranged on the side surface of the small arm, the introduction of the third driving wheel, the fourth driving wheel and the second driving belt does not interfere with the rotation of the small arm rod piece, and the small arm rod piece can still rotate 360 degrees without restriction.

In the unconstrained rotation process of the large arm rod piece and the small arm rod piece, the posture self-maintenance of the terminal platform is realized through the first transmission wheel, the second transmission wheel, the third transmission wheel, the fourth transmission wheel, the first transmission belt and the second transmission belt; different from a four-bar mechanism, the working conditions of a synchronous wheel and a synchronous belt are constant in the full circumference range; therefore, the mechanical arm provided by the invention can realize the self-holding of the terminal posture of the mechanical arm without dead points under the condition that the large arm rod piece and the small arm rod piece rotate by 360 degrees.

In this embodiment, the first driving wheel, the second driving wheel, the third driving wheel and the fourth driving wheel preferably adopt synchronous wheels with the same outer diameter and tooth number, and the first driving belt and the second driving belt preferably adopt synchronous belts.

In the use process of the embodiment 1, the small arm rod member always hangs down under the action of gravity, so the moving range of the terminal platform is limited (limited in the moving range of the large arm rod member). For this purpose, example 2 is modified accordingly.

The embodiment 2 is basically the same as the embodiment 1, and the only difference is that a small arm motor 15 is arranged at the tail end of a large arm rod piece, and a driving screw rod 17 is connected to a small arm motor shaft through a coupler; a driven gear 16 engaged with the drive screw is fixed to the arm connecting shaft. After the small arm motor is electrified and started, the small arm rod piece can be driven to rotate around the axis of the arm connecting shaft; therefore, the moving range of the terminal platform can be obviously expanded, and the working range of the invention is expanded.

Claims

1. A terminal attitude self-holding device of a mechanical arm comprises a large arm motor (1) arranged on a rack, a large arm rod piece (2) with the initial end arranged on the shaft of the large arm motor, a small arm rod piece (3) with the initial end hinged with the tail end of the large arm rod piece through a hollow arm connecting shaft (7), a terminal shaft (4) rotatably positioned at the tail end of the small arm rod piece, and a terminal platform (5) fixed on the terminal shaft; the method is characterized in that: the device also comprises a first driving wheel (6) which is fixed on a large arm motor flange or a large arm motor base and is coaxially arranged with a large arm motor shaft, a wheel connecting shaft (10) which is rotatably inserted and positioned in an inner cavity of the arm connecting shaft, and two ends of the wheel connecting shaft extend out of the inner cavity and are respectively fixed with a second driving wheel and a third driving wheel, a fourth driving wheel (11) which is arranged on a terminal shaft, a first driving belt (12) which is simultaneously meshed and matched with the first driving wheel and the second driving wheel, and a second driving belt (13) which is simultaneously meshed and matched with the third driving wheel and the fourth driving wheel;

2. The robot arm terminal posture self-holding device of claim 1, wherein: the first driving wheel is sleeved on the large arm motor shaft in a penetrating manner through a center hole of the first driving wheel.

3. The robot arm terminal posture self-holding device of claim 2, wherein: and a central hole of the fourth driving wheel is sleeved and fixed on the terminal shaft.

4. The robot arm terminal posture self-holding device of claim 3, wherein: the first transmission wheel and the second transmission wheel have the same outer diameter and tooth number and are meshed and connected through a first transmission belt.

5. The robot arm terminal posture self-holding device of claim 4, wherein: the third driving wheel and the fourth driving wheel have the same outer diameter and tooth number and are meshed and connected by a second driving belt.

6. The robot arm terminal posture self-holding device of claim 5, wherein: the first transmission wheel to the fourth transmission wheel are all synchronous wheels or chain wheels, and the first transmission belt and the second transmission belt are synchronous belts matched with the synchronous wheels or chains matched with the chain wheels.

7. The robot arm terminal posture self-holding device of claim 6, wherein: the small arm rod piece is fixed with the arm connecting shaft; a small arm motor (15) is arranged at the tail end of the large arm rod piece, and a driving screw rod (17) is fixed on a motor shaft of the small arm; a driven gear (16) engaged with the driving screw is fixed on the arm connecting shaft.