CN216731799U

CN216731799U - Joint driver and robot

Info

Publication number: CN216731799U
Application number: CN202123258341.3U
Authority: CN
Inventors: 宋庭科; 王轩; 安然
Original assignee: Foshan Feixi Robot Technology Co ltd
Current assignee: Foshan Feixi Robot Technology Co ltd
Priority date: 2021-12-21
Filing date: 2021-12-21
Publication date: 2022-06-14
Anticipated expiration: 2031-12-21

Abstract

The present application relates to a joint driver and a robot. A joint driver, comprising: a servo motor including a motor rotor; the brake disc is fixed on the motor rotor; the friction ring is wound around the brake disc; the bearing is rotatably sleeved on the motor rotor; the electromagnet assembly is fixedly arranged on the bearing; the baffle is fixed with the electromagnet assembly; the armature is sleeved on the motor rotor in a sliding mode and is positioned between the baffle and the electromagnet assembly; the elastic component is arranged between the armature and the electromagnet component; when the electromagnet assembly is powered off, the armature is propped by the elastic assembly and moves towards the direction close to the baffle plate, so that the friction ring is clamped by the armature and the baffle plate to realize braking. The joint driver is simple in overall structure, the condition that fatigue damage or fracture is caused by mutual collision of the firing pin and the brake teeth in the existing scheme is avoided, and the service life is prolonged.

Description

Joint driver and robot

Technical Field

The utility model relates to a robotechnology field especially relates to a joint driver and robot.

Background

Industrial robots are known as automatically controlled reprogrammable multi-purpose manipulators with multiple degrees of freedom and the ability to independently perform work tasks. It may have several axes, each powered by an actuator such as an electric motor. The movement of each motor is stopped by a brake that resists the movement of the motor.

A conventional brake mechanism includes: the friction piece is fixedly connected with the motor rotor; the brake piece is abutted against one side of the friction piece; the thrust piece is abutted against the other side of the friction piece and used for providing thrust for the brake piece, and the thrust of the thrust piece to the brake piece is adjustable; and the locking mechanism is used for preventing the brake piece from rotating according to a brake command. The locking mechanism comprises a striker and a driving piece which are connected with each other, the outer ring of the brake piece is provided with brake teeth, and the driving piece is used for driving the striker to stretch and retract so that the striker can extend out to be in contact with the brake teeth in response to the brake command, and the brake piece is prevented from rotating.

The multi-disc brake can realize braking, but has some obvious disadvantages:

1. occupies too much axial dimension and has uneven weight distribution in the circumferential direction.

Because the electromagnetic switch is installed along the axial direction, the overall axial dimension of the joint is larger, and the structural form and installation of other components are further influenced; the axial space inside the joint is very limited and the structure is not compact enough in the axial direction.

2. The brake collision reliability and the service life are lower.

As the number of collisions increases, the collision portion between the striker and the brake tooth wears many small dimples and debris, resulting in reduced reliability and life.

SUMMERY OF THE UTILITY MODEL

In view of the above, it is desirable to provide a joint actuator and a robot having high reliability and long life.

A joint driver, comprising: a servo motor including a motor rotor; the brake disc is fixed on the motor rotor; the friction ring is wound around the brake disc; the bearing is rotatably sleeved on the motor rotor; the electromagnet assembly is fixedly arranged on the bearing; the baffle is fixed with the electromagnet assembly and is positioned on one side of the friction ring; the armature is sleeved on the motor rotor in a sliding mode and located on the other side of the friction ring, and the armature is located between the baffle and the electromagnet assembly; the elastic component is arranged between the armature and the electromagnet component; when the electromagnet assembly is powered off, the armature is propped by the elastic assembly to move towards the direction close to the baffle plate, so that the friction ring is clamped by the armature and the baffle plate to realize braking.

In one embodiment, the motor rotor is provided with a key slot, the inner edge of the brake disc is provided with a positioning slot, the brake assembly further comprises a fixing key, and the brake disc is fixed on the motor rotor through the fixing key which is inserted into the key slot and the positioning slot simultaneously.

A robot comprises the joint driver.

In one embodiment, the robot further comprises a plurality of mechanical arms and a plurality of joints, the mechanical arms are connected in sequence, adjacent mechanical arms are connected through the joints, and the joints are provided with the joint drivers.

According to the joint driver, when braking is needed, the electromagnet assembly is powered off, the armature moves towards the direction close to the baffle under the action of the elastic force of the spring, so that the armature and the baffle are clamped from two sides of the friction ring, and finally the motor rotor stops rotating under the action of friction torque, and braking is achieved. Overall structure is simple, and occupation space is little, has avoided among the current scheme striker and the brake tooth collision each other and lead to the condition of fatigue failure or fracture, has improved working life.

Drawings

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings. Like reference numerals refer to like parts throughout the drawings, and the drawings are not intended to be drawn to scale in actual dimensions, emphasis instead being placed upon illustrating the principles of the invention.

FIG. 1 is a perspective view of a brake assembly according to one embodiment;

FIG. 2 is a front view of the brake assembly shown in FIG. 1;

FIG. 3 is an exploded perspective view of the brake assembly shown in FIG. 1;

FIG. 4 is a cross-sectional view taken along line A-A of FIG. 2;

FIG. 5 is a schematic view of the friction ring in combination with a brake disc;

FIG. 6 is a schematic view of a joint driver according to an embodiment;

fig. 7 is a schematic diagram of a robot according to an embodiment.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail with reference to the accompanying drawings and the following detailed description. It should be understood that the detailed description and specific examples, while indicating the scope of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. When an element is referred to as being "abutted" to another element, it can be directly abutted to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like as used herein are for illustrative purposes only and do not represent the only embodiments.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The drivers in each joint of the robot can drive the robot arm connected with the driver to move. The driver generally comprises a servo motor, a harmonic reducer, an encoder, a driving circuit and the like. In addition, a brake assembly is arranged in the driver and can be used for stopping the movement of the robot arm or keeping the robot arm in a certain spatial posture.

A servo motor is an engine that controls the operation of mechanical elements in a servo system, and is an auxiliary motor indirect transmission.

The servo motor can control the speed, the position precision is very accurate, and a voltage signal can be converted into torque and rotating speed to drive a control object. The rotation speed of the rotor of the servo motor is controlled by an input signal and can quickly respond, the servo motor is used as an actuating element in an automatic control system, has the characteristics of small electromechanical time constant, high linearity and the like, and can convert a received electric signal into angular displacement or angular speed on a motor shaft for output. The servo motor is divided into two categories of direct current servo motors and alternating current servo motors, and is mainly characterized in that when the signal voltage is zero, the signal voltage has no autorotation phenomenon, and the rotating speed is reduced at a constant speed along with the increase of the torque.

Referring to fig. 1 to 3, according to an embodiment of the present application, a brake assembly 100 for a robot is provided, which includes a motor rotor 10, a brake disc 20, a friction ring 30, a bearing 40, an electromagnet assembly 50, a baffle 60, an armature 70, and an elastic assembly 80. The brake disc 20 and the friction ring 30 are sleeved and fixed on the motor rotor 10. The bearing 40 is movably sleeved on the motor rotor 10, and the electromagnet assembly 50, the baffle 60 and the armature 70 are fixed with the bearing 40.

As shown in fig. 3, the motor rotor 10 is a cylindrical shaft extending from the servo motor 230 (see fig. 7). The motor rotor 10 is provided with a plurality of axially extending keyways 12. In this embodiment, four key slots 12 are uniformly spaced on the circumferential surface of the motor rotor 10. The brake disc 20 is generally annular and has a plurality of locating slots 22 formed in its inner edge which correspond to the keyways 12. Brake assembly 100 also includes a plurality of fixed keys 18. The fixing key 18 is inserted into the key groove 12 and the positioning groove 22 at the same time, so that the brake disc 20 is fixed on the motor rotor 10 through the fixing key 18, so that the brake disc 20 rotates with the motor rotor 10. In the present embodiment, the fixing key 18 is a hook key, which can achieve accurate positioning in three directions, namely radial direction, circumferential direction and axial direction. In addition, the fixed key 18 is in interference fit with the motor rotor 10, and the two sides of the fixed key 18 are pressed into the key groove 12 after being coated with the first adhesive layer during installation, so that the stability and the reliability of the structure are enhanced. Specifically, the first adhesive may be loctite 609 glue.

Referring to fig. 3 and 4, the motor rotor 10 is further provided with a first annular positioning boss 14. The brake assembly 100 also includes a washer 90. The washer 90 is located between the first positioning boss 14 and the brake disc 20 for adjusting the position of the brake disc 20 in the axial direction of the motor rotor 10. Since the outer diameter of the first positioning boss 14 is larger than the inner diameter of the brake disc 20, the brake disc 20 can abut against the first positioning boss 14 through the gasket 90, so that the brake disc 20 can be positioned in the axial direction of the motor rotor 10.

Referring to fig. 3 and 5, the brake disc 20, which is substantially annular, may be made of a metal material. The friction ring 30 is substantially annular and is fixed around the brake disc 20 and is arranged coplanar with the brake disc 20. The friction ring 30 may be made of a non-metallic material, such as ceramic, rubber, or other engineering plastic with a suitable coefficient of friction. The outer edge of the brake disc 20 extends radially to form the blades 24, and the inner edge of the friction ring 30 is provided with receiving grooves 32 for receiving the blades 24. In this embodiment, the blade 24 is generally U-shaped and includes two spaced and

parallel prongs

242, 244, the

prongs

242, 244 contacting opposite sidewalls of the receiving slot 32. In the present embodiment, the number of the blades 24 is six, and six blades 24 are uniformly and symmetrically distributed at intervals of 60 ° on the outer edge of the brake disc 20. The number and positions of the receiving grooves 32 correspond one-to-one to the vanes 24.

When the motor rotor 10 starts to accelerate from a standstill to rotate counterclockwise, the brake disc 20 will start to accelerate with the motor rotor 10, and the fork arm 242 will generate a great pressure F1 to one side wall of the receiving groove 32 to rotate the friction ring 30 together. When the friction ring 30 is clamped by the armature 70 and the stop plate 60 to effect braking, the side walls of the receiving groove 32 exert a great pressure F1' on the yoke 242. Because the fork arms 242 are long and thin rods and the brake disc 20 is made of a material with good flexibility, when the friction ring 30 is clamped by the armature 70 and the baffle 60 to stop rotating, the six fork arms 242 are subjected to resistance forces F1 'of the six receiving grooves 32 (each fork arm 242 is subjected to different forces F1'), and bending deformation (flexibility) is generated to different degrees. Then the yoke 242 is restored to its original shape by its own elastic force, and the motor rotor 10 stops rotating. Similarly, when the motor rotor 10 rotates clockwise from a stationary state, the brake disc 20 will start to rotate with the motor rotor 10 at an accelerated speed, and the fork arm 244 will generate a great pressure F2 on the other side wall of the receiving groove 32 to rotate the friction ring 30. When the friction ring 30 is clamped by the armature 70 and the stop plate 60 to effect braking, the side walls of the receiving groove 32 exert a large pressure force F2' on the yoke 244. Because the fork arms 244 are long and thin rods and the brake disc 20 is made of a material with good flexibility, when the friction ring 30 is clamped by the armature 70 and the baffle 60 to stop rotating, the six fork arms 244 are subjected to resistance forces F2 'of the six receiving grooves 32 (each fork arm 244 is subjected to different forces F2'), and thus, different degrees of bending deformation (flexibility) are generated. Then the yoke 244 is restored under its own elastic force, and the motor rotor 10 stops rotating. The yoke 244 may be slightly deformed by bending, resulting in deflection. Therefore, when the brake disc is started or braked, the

U-shaped yoke arms

242 and 244 of the brake disc 20 can absorb impact energy generated by collision through elastic deformation, and further protect other parts such as a speed reducer in a joint. In addition, compared with the existing single-blade scheme, each of the six

fork arms

244 or 242 is always subjected to a force in one direction, so that the defect that the conventional single blade is easily subjected to fatigue failure and breakage due to repeated large impact forces from the left direction and the right direction is overcome, and the service life and the reliability of the brake disc 20 are improved.

Referring to fig. 3 and 4, the bearing 40 is disposed at the end of the motor rotor 10. The bearing inner ring of the bearing 40 is fixed with the motor rotor 10 in an interference fit manner, and the bearing outer ring of the bearing 40 can freely rotate relative to the bearing inner ring. In this embodiment, the bearing 40 is a deep groove ball bearing, which is characterized by low frictional resistance and high rotational speed, and can be used in a mechanism for bearing radial load or combined load acting in both radial and axial directions. The motor rotor 10 is further provided with an annular second positioning boss 16. The outer diameter of the second positioning boss 16 is larger than the inner diameter of the bearing inner race of the bearing 40, so that one side of the bearing 40 can abut against the second positioning boss 16, thereby positioning the bearing 40 in the axial direction of the motor rotor 10.

The electromagnet assembly 50 is fixedly arranged on the bearing 40. As shown in fig. 3, the electromagnet assembly 50 includes a housing 52 and an electromagnet 54 housed in the housing 52. The housing 52 is substantially annular, and has an annular receiving chamber 522 formed on one side thereof. The annular electromagnet 54 is fixedly received within the receiving chamber 522 and opposes the armature 70. The depth of the receiving cavity 522 is less than the thickness of the housing 52, thereby dividing the housing 52 into an inner race 524 and an outer race 526. The inner race 524 and the outer race 526 are flush and joined at their edges (see fig. 4). The inner ring 524 is fixedly secured to the bearing outer ring of the bearing 40 and is in interference fit with the bearing outer ring. In this embodiment, the bearing outer ring of the bearing 40 is further coated with a second adhesive layer to enhance the connection strength between the bearing 40 and the electromagnet assembly 50. The second adhesive may also be loctite 609 glue. The elastomeric assembly 80 is disposed on the outer race 526. Specifically, the outer ring 526 defines a plurality of receiving holes 528, and the plurality of elastic elements 80 are respectively received in the plurality of receiving holes 528. Each receiving hole 528 extends through both sides of the outer ring 526. The receiving hole 528 further includes a spring receiving portion 5282 and a threaded portion 5284. The spring receiving portion 5282 is opposite the armature 70 and the threaded portion 5284 is in communication with the spring receiving portion 5282 but on the side of the outer race 526 remote from the armature 70. The diameter of the spring receiving portion 5282 is slightly larger than the diameter of the threaded portion 5284.

Resilient assembly 80 the resilient assembly 80 includes a spring 82, an adjustment screw 84 and a washer 86. One end of the spring 82 is received in the spring receiving portion 5282 of the receiving hole 528, and the other end of the spring 82 protrudes out of the spring receiving portion 5282 and can abut against one side of the armature 70. The adjustment screw 84 is screwed into the threaded portion 5284 of the receiving hole 528, and is axially movable by rotation at the threaded portion 5284. A washer 86 is located between the spring 82 and the adjustment screw 84. Therefore, the position of the adjusting screw 84 on the threaded portion 5284 can be adjusted by an L-shaped wrench, so that the initial compression amount of the spring 82 can be accurately adjusted (the larger the compression deformation of the spring is, the larger the elastic force is), and further, the elastic pressing force of the spring 82 on the armature 70 is adjusted, so that the friction force of the armature 70 on the friction ring 30 can be adjusted. Of course, the spacer 86 could be omitted, with the adjustment screw 84 directly abutting the end of the spring 82. In this embodiment, the number of the elastic members 80 is six, and six elastic members 80 are uniformly and symmetrically distributed on the outer ring 526 at 60 ° intervals.

The armature 70 is substantially annular, and is sleeved on the motor rotor 10 and can slide left and right along the axial direction of the motor rotor 10. The armature 70 is located on one side of the disc 20 and the friction ring 30 and the stop 60 is located on the other side of the disc 20 and the friction ring 30. The baffle 60 is substantially annular, and is disposed on the motor rotor 10 and fixed to the electromagnet assembly 50. Specifically, as shown in fig. 3, the baffle 60 is provided with a limit protrusion 62 extending along the axial direction, the armature 70 is provided with a notch 72 corresponding to the limit protrusion 62, and the baffle 60 is fixed on the outer ring 526 of the electromagnet assembly 50 by a screw 64 extending through the limit protrusion 62. Therefore, the baffle 60 and the electromagnet assembly 50 are fixed to each other and do not rotate together with the motor rotor 10, and the armature 70 can slide between the baffle 60 and the electromagnet assembly 50 in the axial direction of the motor rotor 10.

The operation of the brake assembly 100 is briefly described as follows.

When the brake is not required for normal movement of the joint, the electromagnet assembly 50 is normally energized and the electromagnet 54 becomes magnetic to attract the armature 70, whereupon the armature 70 will move away from the back plate 60 against the spring force of the spring 82 and thereby disengage from the friction ring 30. At this time, the gap between the baffle 60 and the armature 70 is greater than the thickness of the friction ring 30, there is no friction force between the baffle 60 and the friction ring 30 or the friction force is much smaller than the braking force available for braking, and at this time, the brake disc 20 is in a brake-released state, and the motor rotor 10 can rotate, so as to drive the brake disc 20 and the friction ring 30 to normally rotate together.

When the joint needs braking, the electromagnet assembly 50 is powered off, the electromagnet 54 loses magnetism, the armature 70 moves towards the direction close to the baffle 60 under the action of the elastic force of the spring 82, so that the armature 70 and the baffle 60 clamp the friction ring 30 from two sides, the friction torque acting on the friction ring 30 is transmitted to the brake disc 20 through the slightly elastically deformable blades 24, and finally the motor rotor 10 stops rotating under the action of the friction torque through the fixed key 18, so that the braking is realized. It will be appreciated that the current flowing through the electromagnet assembly 50 may also be gradually reduced, resulting in a gradually increasing spring force of the spring 82 against the armature 70, i.e., a gradually increasing clamping force of the armature 70 against the friction ring 30, thereby producing a more refined braking effect.

In summary, the brake assembly 100 of the present embodiment has the following advantages:

1. the brake friction force can be adjusted. The plurality of elastic assemblies 80 are uniformly distributed on the outer ring 526 of the electromagnet assembly 50, and the elastic force of the spring 82 can be adjusted and calibrated through the adjusting screw 84, so that the friction force is adjusted.

2. Novel friction structure. The traditional structure is that two friction rings are arranged between two movable armatures, and a friction wheel is arranged between the two friction rings, so that the structure has the defects of more parts, large magnetic force required by brake control and easy abrasion of a brake pad. The core structure of the present application is that the baffle 60 and the armature 70 are fixed and movable, and the brake disc 20 and the friction ring 30 are arranged between the baffle and the armature, and the U-shaped fork arm of the brake disc 20 and the accommodating groove 32 of the friction ring 30 are in concave-convex embedding. During movement, the brake disc 20 rotates with the friction ring 30; during braking, the baffle 60 and the armature 70 clamp the friction ring 30 made of the non-metal material, and the friction ring 30 stops rotating after blocking the brake disc 20, so that the brake disc 20 only generates recoverable bending deformation without wearing the brake disc 20, and the brake disc has the advantages of few parts, small required electromagnetic force, simple control and high braking precision.

3. A novel fastening mode. The brake disc 20 and the motor rotor 10 are fastened through the fixing keys 18 and 609 glue, so that the installation is convenient, and the fastening is reliable.

4. Stronger system robustness and functional reliability. Compared with the prior art, the contact surface between the baffle 60 and the armature 70 and the friction ring 30 is large, the friction torque generated by uniform circumferential fitting is more stable, the condition that the collision between the striker and the brake teeth in the prior art causes fatigue damage and breakage is avoided, and the service life is prolonged.

5. The brake assembly 100 of the present embodiment is more compact in layout, and greatly saves the axial space inside the joint. The diameter of the brake assembly 100 can be within 60mm, the thickness can be within 20mm, and the total weight is lighter.

6. All parts of this application all are circumference evenly symmetric distribution, have good dynamic balance effect.

7. The braking system is simple in structure, can be modularly designed and produced, is suitable for wide revolving body braking application scenes, and can be used by connecting a plurality of braking structures in series in one system.

Fig. 6 is a block diagram illustrating a system connection structure of the joint driver 200 for a robot according to the present invention. The joint driver 200 mainly includes: a driving circuit 210 for implementing precise control of the motor output shaft; the photoelectric pulse encoder 220 is used for measuring the speed of the joint output end; a servo motor 230 with a hall sensor for providing a driving force output; and the harmonic reducer 240 is used for reducing the rotating speed and improving the driving torque. The joint driver 200 further includes a brake assembly 100 located between the servo motor 230 and the encoder 220. The servo motor 230 includes a motor rotor 10.

Fig. 7 shows an industrial robot 300 with multiple degrees of freedom (DOF). The robot has six axes and each joint of the axes is driven by an actuator. The robot includes a plurality of robot arms 320 and a plurality of joints 340, the plurality of robot arms 320 are connected in sequence, adjacent robot arms 320 are connected by the joints, and the joint driver 200 is provided in the joints.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only represent several embodiments of the present invention, and the description thereof is more specific and detailed, but not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the spirit of the present invention, several variations and modifications can be made, which are within the scope of the present invention. Therefore, the protection scope of the present invention should be subject to the appended claims.

Claims

1. An articulation driver, comprising:

a servo motor including a motor rotor;

the brake disc is fixed on the motor rotor;

the friction ring is wound around the brake disc;

the bearing is rotatably sleeved on the motor rotor;

the electromagnet assembly is fixedly arranged on the bearing;

the baffle is fixed with the electromagnet assembly and is positioned on one side of the friction ring;

the armature is sleeved on the motor rotor in a sliding mode and located on the other side of the friction ring, and the armature is located between the brake disc and the electromagnet assembly; and

the elastic component is arranged between the armature and the electromagnet component;

when the electromagnet assembly is powered off, the armature is propped by the elastic assembly to move towards the direction close to the baffle plate, so that the friction ring is clamped by the armature and the baffle plate to realize braking.

2. The joint driver according to claim 1, wherein the motor rotor is provided with a key groove, the inner edge of the brake disc is provided with a positioning groove, the joint driver further comprises a fixing key, and the brake disc is fixed on the motor rotor by the fixing key inserted into the key groove and the positioning groove simultaneously.

3. The joint driver as claimed in claim 1, wherein the motor rotor is provided with a first annular positioning boss, and the joint driver further comprises a washer, the washer being located between the first positioning boss and the brake disc.

4. The joint actuator of claim 1, wherein an outer edge of the brake disc extends radially to form a blade, and an inner edge of the friction ring forms a receiving slot to receive the blade.

5. The joint actuator of claim 4, wherein the blade includes two spaced apart prongs that contact respective opposing sidewalls of the pocket.

6. The joint driver according to claim 1, wherein the blocking plate is provided with a limiting protrusion extending in the axial direction, the armature is provided with a notch opposite to the limiting protrusion, and the blocking plate is fixed to the electromagnet assembly by a screw extending through the limiting protrusion.

7. The joint driver of claim 1, wherein the electromagnet assembly comprises a housing and an electromagnet housed within the housing; the shell comprises an inner ring and an outer ring, the inner ring is fixedly sleeved on the bearing, the outer ring is fixed with the baffle, and the electromagnet is accommodated between the inner ring and the outer ring.

8. The joint driver of claim 7, wherein the outer ring defines a receiving hole, the resilient assembly includes a spring and an adjusting screw, the adjusting screw is movably disposed in the receiving hole, one end of the spring abuts against the adjusting screw, and the other end of the spring abuts against the armature.

9. The joint driver of claim 7, wherein a gap between the flapper and the armature is greater than a thickness of the friction ring when the electromagnet assembly is energized.

10. A robot comprising a joint actuator according to any of claims 1-9.