WO2022040915A1

WO2022040915A1 - Joint assembly and robot

Info

Publication number: WO2022040915A1
Application number: PCT/CN2020/111084
Authority: WO
Inventors: 姚吉隆; 张晟; 杨勇; 赵研峰; 周文娟
Original assignee: 西门子（中国）有限公司
Priority date: 2020-08-25
Filing date: 2020-08-25
Publication date: 2022-03-03
Also published as: CN115885115A

Abstract

A joint assembly, comprising a rotating shaft (10), a rotating disk (20), a piezoelectric ceramic stack (50), a stroke amplifying mechanism (30) and a brake disk (40). The rotating shaft is fixed to a first rotating arm and can be rotatably arranged on a second rotating arm around the axis of the rotating shaft. The rotating disk is fixed to the rotating shaft. The piezoelectric ceramic stack can generate displacement by means of telescopic deformation. The stroke amplifying mechanism comprises a first driving portion (31), which can be driven by the piezoelectric ceramic stack to generate displacement in a braking direction (X), and a second driving portion (33) which is linked to the first driving portion and can generate larger displacement in the braking direction. The brake disk can be driven by the second driving portion to move between a braking position (I), at which the brake disk can stop the rotating disk from rotating, and a release position (II), at which the brake disk is separated from the rotating disk. The joint assembly is fast in response, small in size, light in weight and low in power consumption and operation temperature. The present invention further provides a robot provided with the joint assembly.

Description

Joint components and robots

technical field

The present invention relates to a joint assembly, in particular to a joint assembly capable of realizing emergency braking. The present invention also relates to a robot having the above-mentioned joint assembly.

Background technique

For robots, especially collaborative robots (cobots), their joints usually have emergency braking functions to ensure that the robot's posture can be maintained in emergency situations (such as power failure or collision with objects and people). The current robot joints are usually actuated by electromagnetic brakes and realize the function of emergency braking by abutting or resisting the rotating parts. The response time of the electromagnetic brake is long. In addition, the braking method that generates friction against the rotating parts requires a large volume and weight of the electromagnetic brake, as well as high power consumption and operating temperature; the braking method that resists the rotating parts cannot guarantee After the electromagnetic brake is activated, the rotation of the rotating parts is stopped immediately.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a joint assembly, which realizes quicker response to emergency braking, and is smaller in size and weight, and lower in power consumption and operating temperature.

Another object of the present invention is to provide a robot, the key components of which can realize emergency braking, and are small in size and weight, and low in power consumption and operating temperature.

The invention provides a joint assembly, which includes a rotating shaft, a rotating disk, a piezoelectric ceramic stack, a stroke amplification mechanism and a braking disk. The rotating shaft can be fixed on a first rotating arm, one end of the rotating shaft extends into a second rotating arm, and is arranged on the second rotating arm so as to be rotatable around the axis of the rotating shaft. The rotating disk can be fixed to the rotating shaft in the second rotating arm. The piezoelectric ceramic stack can be arranged in the second rotating arm, and the piezoelectric ceramic stack can be displaced in one telescopic direction through telescopic deformation. The stroke amplification mechanism can be arranged in the second rotating arm, and the stroke amplification mechanism includes a first driving part and a second driving part. The first driving part can move under the driving of the piezoelectric ceramic stack and generate displacement in a braking direction parallel to the axis of the rotating shaft. The second driving part can be linked with the first driving part to generate displacement in the braking direction, and the displacement generated by the second driving part in the braking direction is greater than the displacement generated by the first driving part in the braking direction. The brake disc can be arranged in the second rotating arm and can be driven by the second driving part to move between a braking position and a releasing position, wherein the braking disc in the braking position can abut against the rotating disc, and the brake disc is located in the braking position. The brake disc in the release position can be separated from the rotating disc.

The joint assembly provided by the present invention uses the piezoelectric ceramic stack to generate deformation under the inverse piezoelectric effect, amplifies the stroke and drives the brake disc through the stroke amplifying mechanism, and then the brake disc abuts against the rotating disc fixed to the rotating shaft. The frictional force generated prevents the rotation of the rotating shaft, thereby realizing the emergency braking function. The joint assembly provided by the invention generates power by stacking piezoelectric ceramics, has faster action response, smaller volume and weight, and lower power consumption and operating temperature.

In yet another exemplary embodiment of the joint assembly, the joint assembly further includes a braking portion, which is located on the side of the rotating disc facing away from the braking disc in the braking direction. The rotating disk includes a rotating disk body, a braking member and a first driving member. The braking member is movably penetrated through the rotating disc body along the braking direction between a contact position and a separation position, the braking member at the contact position can abut against the braking portion and prevent the rotating disc from rotating through frictional force, and is located at the contact position. The brake member at the release position can be separated from the brake portion, and the brake disc can be driven to move from the release position to the contact position during the movement of the brake disc from the release position to the brake position. The first driving member applies force to the rotating disc body and the braking member, respectively, and provides a driving force for moving the braking member toward the separation position. In this way, it can be avoided that the rotating disk is subjected to a force in the axial direction and the stability of the rotating shaft is affected.

In yet another exemplary embodiment of the joint assembly, the rotating disc has a plurality of braking members, and the plurality of braking members are evenly arranged around the axis of the rotating disc body. Thereby, the friction force generated by the braking member against the braking portion can evenly act on the rotating disc body, thereby improving the stability during braking.

In another exemplary embodiment of the joint assembly, a high friction coefficient material is provided on the braking member at a portion in contact with the braking portion. Thereby, the friction force between the braking element and the braking part is increased, and the speed during braking is increased.

In another exemplary embodiment of the joint assembly, the braking portion is a housing of the second rotating arm.

In another illustrative embodiment of the joint assembly, the stroke amplification mechanism includes a rotating rod. The rotating rod is rotatably arranged in the second rotating arm around a first axis perpendicular to the braking direction, the first driving part and the second driving part are respectively located in the rotating rod, and the distance between the first driving part and the first axis is smaller than the first driving part and the first axis; 2. The distance between the driving part and the first axis.

In another exemplary embodiment of the joint assembly, the joint assembly further includes a first link and a second link. Two ends of the first connecting rod are respectively connected to one end of the first driving part and one end of the piezoelectric ceramic stack along the braking direction in a rotational direction parallel to the first axis. Both ends of the second connecting rod are respectively connected to the second driving part and the brake disc in a rotatable manner around the first axis, and the rotation axis is parallel to the first axis.

In another exemplary embodiment of the joint assembly, the piezoceramic stack protrudes toward the brake disc in the braking direction after power-on and retracts in the opposite direction of the braking direction after power-off.

In another exemplary embodiment of the joint assembly, the first driving part and the second driving part are located on both sides of the first axis in a direction perpendicular to the first axis and the braking direction, so that the first driving part During the linkage process with the second driving part, reverse displacement is generated in the braking direction. The joint assembly also includes a second drive member that applies force to the second pivot arm and the brake disc, respectively, and provides a driving force to move the brake disc toward the braking position.

In another exemplary embodiment of the joint assembly, the second driving member is a spring which urges the second rotating arm and the brake disc respectively and provides an elastic driving force to move the brake disc towards the braking position.

The present invention also provides a robot comprising a first rotating arm, a second rotating arm and the above-mentioned joint assembly. The rotating shaft is fixed on the first rotating arm, one end of the rotating shaft extends into the second rotating arm, and is rotatably arranged on the second rotating arm around the axis of the rotating shaft. The rotating disc, the stroke amplifying mechanism, the brake disc and the piezoelectric ceramic are stacked is arranged in the second rotating arm.

Description of drawings

The following drawings merely illustrate and explain the present invention schematically, and do not limit the scope of the present invention.

FIG. 1 is a schematic structural diagram of an exemplary embodiment of a joint assembly.

FIG. 2 is a schematic diagram of a variation of the joint assembly.

FIG. 3 is a schematic view of the structure of the rotating disk.

FIG. 4 is a schematic structural diagram of another exemplary embodiment of the joint assembly.

Label description

10 Rotary axis

20 Turn the disc

22 Turn the disc body

24 Brakes

26 First drive

30 Stroke amplification mechanism

31 The first drive part

32 Turn lever

33 Second drive part

34 The first link

36 Second link

40 brake discs

50 Piezo Stacks

60 Brakes

70 Second drive

R1 Axis of Rotation Shaft

R2 first axis

X Braking direction

detailed description

In order to have a clearer understanding of the technical features, purposes and effects of the invention, the specific embodiments of the invention will now be described with reference to the accompanying drawings. The same reference numerals in each figure denote components with the same structure or similar structure but the same function.

As used herein, "schematic" means "serving as an example, instance, or illustration" and any illustration, embodiment described herein as "schematic" should not be construed as a preferred or advantageous one Technical solutions.

In order to keep the drawings concise, the drawings only schematically show the parts related to the present invention, and they do not represent its actual structure as a product.

FIG. 1 is a schematic structural diagram of an exemplary embodiment of a joint assembly. 1 , the joint assembly includes a rotating shaft 10 , a rotating disk 20 , a piezoelectric ceramic stack 50 , a stroke amplifying mechanism 30 and a braking disk 40 .

The rotating shaft 10 can be fixed to a first rotating arm, one end of the rotating shaft 10 extends into a second rotating arm, and is rotatably arranged on the second rotating arm around the axis R1 of the rotating shaft 10 . Thereby, the rotational connection of the first rotating arm and the second rotating arm is achieved.

The rotating disk 20 can be fixed to the rotating shaft 10 in the second rotating arm. The piezoelectric ceramic stack 50 can be arranged in the second rotating arm. An inverse piezoelectric effect can be generated on the piezoelectric ceramic stack 50 as a dielectric. The inverse piezoelectric effect means that when an electric field is applied in the polarization direction of dielectrics, these dielectrics produce mechanical deformation or mechanical pressure in a certain direction. When the applied electric field is removed, these deformations or stresses also disappear. Under the influence of the inverse piezoelectric effect, the piezoelectric ceramic stack 50 can be displaced in one expansion and contraction direction through expansion and contraction. In the exemplary embodiment, the telescopic direction is parallel to one braking direction X, which is parallel to the axis of the rotating shaft 10 . However, it is not limited to this, and in other exemplary embodiments, the telescopic direction can also be adjusted according to actual needs.

The stroke amplification mechanism 30 can be provided in the second rotating arm. The stroke amplification mechanism 30 includes a first driving part 31 and a second driving part 33 . FIG. 2 is a schematic diagram of a variation of the joint assembly. Referring to FIG. 2 , the first driving part 31 can move and generate displacement in the braking direction X under the driving of the piezoelectric ceramic stack 50 . The second driving part 33 can be linked with the first driving part 31 to generate displacement in the braking direction X, and the displacement generated by the second driving part 33 in the braking direction X is larger than that of the first driving part 31 in the braking direction X resulting displacement.

The brake disc 40 can be arranged in the second rotating arm, and the brake disc 40 can be driven by the second driving part 33 between a braking position I as shown in FIG. 2 and a release position II as shown in FIG. 1 . between sports. 2, the brake disc 40 in the braking position I can abut against the rotating disc 20, and prevent the rotating disc 20 from rotating by the frictional force generated by the abutment. Referring to FIG. 1 , the brake disc 40 in the release position II can be separated from the rotating disc 20 and released.

In an exemplary embodiment, referring to FIGS. 1 and 2 , the stroke magnification mechanism 30 includes a pivot lever 32 . The rotating lever 32 is arranged in the second rotating arm so as to rotate about a first axis R2 perpendicular to the braking direction X and perpendicular to the drawing direction in the figure. The first driving part 31 and the second driving part 33 are respectively located on the rotating rod 32 , and the distance between the first driving part 31 and the first axis R2 is smaller than the distance between the second driving part 33 and the first axis R2 . The joint assembly also includes a first link 34 and a second link 36 . Both ends of the first link 34 are respectively rotatably connected to one end of the first driving part 31 and the piezoelectric ceramic stack 50 facing the brake disc 40 along the braking direction X around a rotation axis parallel to the first axis R2 . Both ends of the second link 36 are respectively rotatably connected to the second driving part 33 and the brake disc 40 around a rotation axis parallel to the first axis R2. The piezoelectric ceramic stack 50 , the rotating rod 32 and the brake disc 40 are linked together by the first link 34 and the second link 36 . And by turning the lever 32 , in the braking direction X, the stroke of the piezoceramic stack 50 can be amplified on one side of the brake disc 40 . However, it is not limited to this. In other exemplary embodiments, the first link 34 and the second link 36 can be replaced by other structures, and the stroke amplifying mechanism 30 can also use other structures with the same function, such as a hydraulic stroke amplifier. Wait.

The joint assembly provided by the present invention utilizes the characteristic of the piezoelectric ceramic stack 50 to generate deformation under the inverse piezoelectric effect, amplifies the stroke through the stroke amplifying mechanism 30 and drives the brake disc 40, and then the brake disc 40 is abutted against and fixed to the rotating The frictional force generated by the rotating disk 20 of the shaft 10 prevents the rotating shaft 10 from rotating, thereby realizing the emergency braking function. The joint assembly provided by the present invention generates driving force by stacking piezoelectric ceramics, has faster action response, smaller volume and weight, and lower power consumption and operating temperature.

In the exemplary embodiment, referring to FIGS. 1 and 2 , the joint assembly further includes a braking portion 60 , which is the housing of the second rotating arm. The braking portion 60 is located in the braking direction X on the side of the rotary disk 20 facing away from the brake disk 40 . The rotating disk 20 includes a rotating disk body 22 , several braking members 24 and several first driving members 26 . The braking member 24 is movably penetrated through the rotating disc body 22 along the braking direction X between a contact position as shown in FIG. 2 and a separation position as shown in FIG. 1 . Referring to FIG. 2 , the braking member 24 in the contact position can abut against the braking portion 60 and prevent the rotating disk 20 from rotating by frictional force. Referring to FIG. 1 , the detent 24 in the disengaged position can be disengaged from the detent portion 60 . The first driving members 26 are elastic cords, and each first driving member 26 exerts force on the rotating disc body 22 and a braking member 24 respectively and provides elastic driving force for moving the braking member 24 toward the separation position. During the movement of the brake disc 40 from the release position II to the braking position I, the braking member 24 can be driven to move from the separation position to the contact position against the elastic driving force of the first driving member 26 . During the movement of the brake disc 40 from the braking position I to the releasing position II, the braking member 24 can be moved from the contact position to the separation position by the elastic driving force of the first driving member 26. The brake disc 40 generates frictional force for braking by abutting the braking member 24 against the braking portion 60 , so as to avoid the axial force on the rotating disc body 22 and ensure the stability of the rotating shaft 10 . Although the first driving member 26 is an elastic cord in the exemplary embodiment, it is not limited thereto, and in other exemplary embodiments, the first driving member 26 may also be other structures with the same function, such as a spring leaf or a permanent magnet.

In the exemplary embodiment, the part of the braking member 24 in contact with the braking portion 60 is provided with a high friction coefficient material, thereby increasing the frictional force between the braking member 24 and the braking portion 60 and improving braking time speed.

FIG. 3 is a schematic view of the structure of the rotating disk. Referring to FIG. 3 , several braking members 24 are evenly arranged around the axis of the rotating disc body 22 . In this way, the friction force generated by the braking member 24 against the braking portion 60 can be evenly distributed to the rotating disc body 22, thereby improving the stability during braking. Although the number of braking members 24 in the exemplary embodiment is six, it is not limited to this. In other exemplary embodiments, the number of braking members 24 can be adjusted according to actual needs, and of course, only one braking member can be included. Piece 24.

FIG. 4 is a schematic structural diagram of another exemplary embodiment of the joint assembly. Referring to FIG. 4 , which is the same or similar to the joint assembly shown in FIG. 1 will not be repeated, the difference is that the first driving part 31 and the second driving part 33 are in a direction perpendicular to the first axis R2 and the braking direction X are located on both sides of the first axis R2, so that the first driving part 31 and the second driving part 33 generate reverse displacement in the braking direction X during the linkage process. In the exemplary embodiment, the joint assembly further includes a second drive member 70, which is a compression spring and applies force to the second pivot arm and the brake disc 40, respectively, to provide the brake disc 40 toward the braking position I The elastic driving force of movement. In use, the piezoelectric ceramic stack 50 protrudes toward the brake disc 40 along the braking direction X after being energized, and can overcome the elastic driving force of the second driving member 70 to drive the brake disc 40 to be at the release position II; the piezoelectric ceramic stack 50 After the power is cut off, it retracts in the opposite direction of the braking direction X, and the brake disc 40 is moved to the braking position I by the elastic driving force of the second driving member 70, whereby the joint assembly can automatically brake after the power is cut off. . In other exemplary embodiments, the second driving member 70 may also be other components capable of providing driving force, such as a permanent magnet.

The present invention also provides a robot. Referring to FIG. 1 , the robot includes a first rotating arm, a second rotating arm, and the above-mentioned joint assembly. The rotating shaft 10 is fixed on the first rotating arm, one end of the rotating shaft 10 extends into the second rotating arm, and is rotatably arranged on the second rotating arm around the axis of the rotating shaft 10, the rotating disc 20, the stroke amplifying mechanism 30, the brake disc 40 and the piezoelectric ceramic stack 50 are disposed in the second rotating arm.

It should be understood that although this specification is described according to various embodiments, not each embodiment only includes an independent technical solution, and this description in the specification is only for the sake of clarity, and those skilled in the art should take the specification as a whole , the technical solutions in each embodiment can also be appropriately combined to form other implementations that can be understood by those skilled in the art.

The series of detailed descriptions listed above are only specific descriptions for the feasible embodiments of the present invention, and they are not used to limit the protection scope of the present invention. Changes, such as combination, division or repetition of features, should be included within the scope of protection of the present invention.

Claims

A joint assembly, characterized in that it includes:

A rotating shaft (10), which can be fixed to a first rotating arm, one end of the rotating shaft (10) extends into a second rotating arm, and is rotatably arranged on the axis of the rotating shaft (10) the second rotating arm;

a rotating disk (20) capable of being fixed to the rotating shaft (10) in the second rotating arm;

A piezoelectric ceramic stack (50), which can be arranged in the second rotating arm, and the piezoelectric ceramic stack (50) can be displaced in a telescopic direction through telescopic deformation;

A stroke amplifying mechanism (30), which can be arranged in the second rotating arm, the stroke amplifying mechanism (30) comprising:

a first driving part (31) capable of moving under the driving of the piezoelectric ceramic stack (50) and generating displacement in a braking direction (X) parallel to the axis of the rotating shaft (10), and

A second driving part (33), which can be linked with the first driving part (31) and generate displacement in the braking direction (X), and the second driving part (33) is in the braking direction (X). The displacement generated in the moving direction (X) is greater than the displacement generated by the first driving part (31) in the braking direction (X); and

A brake disc (40), which can be arranged in the second pivot arm and can be driven by the second driving part (33) between a braking position (I) and a releasing position (II) Movement, wherein the brake disc (40) in the braking position (I) can abut against the rotating disc (20), the brake disc (40) in the release position (II) Can be separated from the rotating disc (20).
The joint assembly according to claim 1, characterized in that, the joint assembly further comprises a braking part (60), which is located in the braking direction (X) and is located away from the rotating disk (20) one side of the brake disc (40);

The rotating disk (20) includes:

a rotating disc body (22);

A braking member (24) is movably penetrated through the rotating disc body (22) along the braking direction (X) between a contact position and a separation position, and all parts located at the contact position The braking member (24) can abut against the braking portion (60) and prevent the rotating disc (20) from rotating through friction, and the braking member (24) in the disengaged position can be connected with the braking member (24) The brake part (60) is disengaged, and the brake disc (40) can drive the brake member (24) from the disengagement during the movement from the release position (II) to the braking position (I). moving the position to the contact position; and

A first drive member (26) that applies force to the rotating disc body (22) and the brake member (24), respectively, and provides a drive to move the brake member (24) toward the disengaged position force.
The joint assembly according to claim 2, characterized in that the rotating disk (20) has a plurality of the braking elements (24), and the braking elements (24) surround the rotating disk body (24). 22) The axes are evenly arranged.
The joint assembly according to claim 2, characterized in that, a portion of the braking member (24) in contact with the braking portion (60) is provided with a high friction coefficient material.
The joint assembly according to claim 2, wherein the braking part (60) is a casing of the second rotating arm.
The joint assembly according to claim 1, characterized in that the stroke amplifying mechanism (30) comprises a rotating rod (32), which is about a first axis (R2) perpendicular to the braking direction (X) The first driving part (31) and the second driving part (33) are respectively located in the rotation rod (32), and the first driving part (31) is rotatably arranged in the second turning arm. ) and the first axis (R2) are smaller than the distance between the second driving part (33) and the first axis (R2).
The joint assembly of claim 6, wherein the joint assembly further comprises:

A first connecting rod (34), two ends of which are respectively rotatably connected to the first driving part (31) and the piezoelectric ceramic stack (50) around a rotation axis parallel to the first axis (R2) one end along said braking direction (X); and

A second connecting rod (36), the two ends of which are respectively connected to the second driving part (33) and the brake disc (40) rotatably around a rotation axis parallel to the first axis (R2).
The joint assembly according to claim 6, characterized in that the extension and retraction direction is parallel to the braking direction (X), and the piezoelectric ceramic stack (50) is energized along the braking direction (X) Extends towards the brake disc (40) and retracts in the opposite direction of the braking direction (X) after de-energization.
The joint assembly according to claim 8, characterized in that, the first driving part (31) and the second driving part (33) are in a direction perpendicular to the first axis (R2) and the braking The direction (X) is located on both sides of the first axis (R2), so that the first driving part (31) and the second driving part (33) are in the braking direction during the linkage process (X) produces a reverse displacement; the joint assembly further includes a second driving member (70), which respectively exerts force on the second rotating arm and the brake disc (40) and provides the brake The driving force for moving the moving disc (40) toward the braking position (I).
The joint assembly according to claim 9, characterized in that, the second driving member (70) is a spring, which exerts force on the second rotating arm and the brake disc (40) respectively and provides the The elastic driving force for the movement of the brake disc (40) towards the braking position (I).
The robot of claim 1, comprising:

a first pivot arm;

a second pivot arm; and

A joint assembly according to any one of claims 1 to 10, wherein the rotating shaft (10) is fixed to the first rotating arm, and one end of the rotating shaft (10) extends into the second rotating arm , and is rotatably arranged on the second rotating arm around the axis of the rotating shaft (10), the rotating disc (20), the stroke amplifying mechanism (30), the brake disc (40) and all The piezoelectric ceramic stack (50) is arranged in the second rotating arm.