Joint assembly and robot

Abstract

The joint assembly includes a rotating shaft (10), a rotating disk (20), a piezoelectric ceramic stack (50), a stroke amplification mechanism (30), and a brake disk (40). The rotating shaft is fixed to a first rotating arm and is rotatably arranged about its axis on a second rotating arm. The rotating disk is fixed to the rotating shaft. The piezoelectric ceramic stack can generate displacement through telescopic deformation. The stroke amplification mechanism includes a first driving part (31) that can generate displacement in the braking direction (X) under the drive of the piezoelectric ceramic stack, and a second driving part (33) that is linked and can generate a greater displacement in the braking direction. The brake disk can be driven by the second driving part to move between a braking position (I) where the rotation of the rotating disk can be blocked and a release position (II) separated from the rotating disk. The joint assembly has a fast response, a small volume and weight, and low power consumption and operating temperature. The present invention also provides a robot having the above joint assembly.

Description

Technical Field

[0001] The present invention relates to a joint assembly, in particular to a joint assembly capable of achieving emergency braking. The present invention also relates to a robot having the above joint assembly. Background Art

[0002] For robots, especially collaborative robots (cobots), their joints usually have an emergency braking function to ensure that the posture of the robot can be maintained in case of emergency (such as power failure or collision with objects and people). Currently, the joints of robots usually use electromagnetic brakes to generate actions and achieve the function of emergency braking by abutting or resisting rotating components. The response time of the electromagnetic brake is relatively long. In addition, the braking method of generating friction by abutting the rotating component requires a relatively large volume and weight of the electromagnetic brake, and has relatively high power consumption and operating temperature; the braking method of resisting the rotating component cannot ensure that the rotating component stops rotating immediately after the electromagnetic brake acts. Summary of the Invention

[0003] The object of the present invention is to provide a joint assembly, which has a faster response to achieve emergency braking, and has a smaller volume and weight, as well as lower power consumption and operating temperature.

[0004] Another object of the present invention is to provide a robot, whose key components can achieve emergency braking, and has a smaller volume and weight, as well as lower power consumption and operating temperature.

[0005] The present invention provides a joint assembly, including a rotating shaft, a rotating disk, a piezoelectric ceramic stack, a stroke amplification mechanism, and a brake disk. The rotating shaft can be fixed to a first rotating arm, one end of the rotating shaft extends into a second rotating arm, and is rotatably arranged in the second rotating arm 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 generate a displacement in a 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 drive of the piezoelectric ceramic stack and generate a 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 and generate a 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 disk 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 release position, wherein the brake disk located at the braking position can abut against the rotating disk, and the brake disk located at the release position can be separated from the rotating disk.

[0006] The joint assembly provided by the present invention utilizes the characteristic that the piezoelectric ceramic stack deforms under the inverse piezoelectric effect. Through a stroke amplification mechanism, the stroke is amplified and the brake disc is driven. Then, the rotation of the rotating shaft is blocked by the frictional force generated when the brake disc abuts against the rotating disc fixed to the rotating shaft, thereby realizing the emergency braking function. The joint assembly provided by the present invention generates power by the piezoelectric ceramic stack, with faster action response, smaller volume and weight, lower power consumption and operating temperature.

[0007] In another illustrative 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 brake disc in the braking direction. The rotating disc includes a rotating disc body, a braking member and a first driving member. The braking member is movably disposed through the rotating disc body between a contact position and a separation position in the braking direction. The braking member located at the contact position can abut against the braking portion and prevent the rotation of the rotating disc through frictional force. The braking member located at the separation position can be separated from the braking portion. During the movement of the brake disc from the release position to the braking position, the braking member can be driven from the separation position to the contact position. The first driving member applies forces to the rotating disc body and the braking member respectively and provides a driving force for the braking member to move towards the separation position. This can avoid the axial force on the rotating disc affecting the stability of the rotating shaft.

[0008] In another illustrative embodiment of the joint assembly, the rotating disc has a plurality of braking members which are evenly arranged around the axis of the rotating disc body. This enables the frictional force generated when the braking members abut against the braking portion to act uniformly on the rotating disc body, improving the stability during braking.

[0009] In another illustrative embodiment of the joint assembly, a material with a high coefficient of friction is provided on the part of the braking member in contact with the braking portion. This increases the frictional force between the braking member and the braking portion and improves the braking speed.

[0010] In another illustrative embodiment of the joint assembly, the braking portion is the housing of the second rotating arm.

[0011] In another illustrative embodiment of the joint assembly, the stroke amplification mechanism includes a rotating rod. The rotating rod is rotatably disposed in the second rotating arm around a first axis perpendicular to the braking direction. The first driving portion and the second driving portion are respectively located on the rotating rod, and the distance between the first driving portion and the first axis is less than the distance between the second driving portion and the first axis.

[0012] In another schematic embodiment of the joint assembly, the joint assembly further includes a first connecting rod and a second connecting rod. Two ends of the first connecting rod are respectively rotatably connected to the first driving part and one end of the piezoelectric ceramic stack along the braking direction around axes parallel to the first axis. Two ends of the second connecting rod are respectively rotatably connected to the second driving part and the brake disc around axes parallel to the first axis, and the rotation axes are parallel to the first axis.

[0013] In another schematic embodiment of the joint assembly, after being powered on, the piezoelectric ceramic stack extends towards the brake disc along the braking direction, and after being powered off, it retracts along the opposite direction of the braking direction.

[0014] In another schematic embodiment of the joint assembly, the first driving part and the second driving part are located on two sides of the first axis in a direction perpendicular to the first axis and the braking direction, so that the first driving part and the second driving part generate reverse displacements in the braking direction during the linkage process. The joint assembly further includes a second driving member, which applies forces to the second rotating arm and the brake disc respectively and provides a driving force for making the brake disc move towards the braking position.

[0015] In another schematic embodiment of the joint assembly, the second driving member is a spring, which applies forces to the second rotating arm and the brake disc respectively and provides an elastic driving force for making the brake disc move towards the braking position.

[0016] The present invention also provides a robot, including a first rotating arm, a second rotating arm and the above-mentioned joint assembly. The rotating shaft is fixed to the first rotating arm, one end of the rotating shaft extends into the second rotating arm, and is rotatably arranged in the second rotating arm around the axis of the rotating shaft. The rotating disc, the stroke amplification mechanism, the brake disc and the piezoelectric ceramic stack are arranged in the second rotating arm. Description of the Drawings

[0017] The following drawings only schematically illustrate and explain the present invention, and do not limit the scope of the present invention.

[0018] Figure 1 It is a schematic structural diagram of a schematic embodiment of the joint assembly.

[0019] Figure 2 It is a schematic diagram of a variation of the joint assembly.

[0020] Figure 3 It is a schematic structural diagram of the rotating disc.

[0021] Figure 4 It is a schematic structural diagram of another schematic embodiment of the joint assembly.

[0022] Reference Signs

[0023] 10 Rotating Shaft

[0024] 20 Rotating disk

[0025] 22 Rotating disk body

[0026] 24 Braking member

[0027] 26 First driving member

[0028] 30 Stroke amplification mechanism

[0029] 31 First driving part

[0030] 32 Rotating rod

[0031] 33 Second driving part

[0032] 34 First connecting rod

[0033] 36 Second connecting rod

[0034] 40 Brake disc

[0035] 50 Piezoelectric ceramic stack

[0036] 60 Braking part

[0037] 70 Second driving member

[0038] R1 Axis of the rotating shaft

[0039] R2 First axis

[0040] X Braking direction Detailed implementation manners

[0041] For a clearer understanding of the technical features, objectives, and effects of the invention, the detailed implementation manners of the invention are now described with reference to the accompanying drawings. In each figure, the same reference numerals denote components having the same or similar structures but the same functions.

[0042] In this document, "schematic" means "serving as an example, instance, or illustration", and any illustration or implementation manner described as "schematic" in this document should not be construed as a more preferred or more advantageous technical solution.

[0043] To simplify the drawings, only the parts related to the invention are schematically shown in each figure, and they do not represent the actual structure of the product.

[0044] Figure 1 It is a schematic structural diagram of a schematic implementation manner of the joint assembly. Refer to Figure 1 , the joint assembly includes a rotating shaft 10, a rotating disk 20, a piezoelectric ceramic stack 50, a stroke amplification mechanism 30, and a brake disc 40.

[0045] 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 in the second rotating arm about the axis R1 of the rotating shaft 10. Thereby, the rotational connection between the first rotating arm and the second rotating arm is achieved.

[0046] The rotating disk 20 can be fixed to the rotating shaft 10 within the second rotating arm. The piezoelectric ceramic stack 50 can be arranged within the second rotating arm. The inverse piezoelectric effect can be generated on the piezoelectric ceramic stack 50 as the dielectric. The inverse piezoelectric effect means that when an electric field is applied in the polarization direction of the dielectric, these dielectrics generate mechanical deformation or mechanical pressure in a certain direction, and when the applied external electric field is removed, these deformations or stresses also disappear. Under the influence of the inverse piezoelectric effect, the piezoelectric ceramic stack 50 can generate a displacement in a telescopic direction through telescopic deformation. In the illustrative embodiment, the telescopic direction is parallel to a braking direction X, and the braking direction X is parallel to the axis of the rotating shaft 10. However, it is not limited thereto, and in other illustrative embodiments, the telescopic direction can also be adjusted according to actual requirements.

[0047] The stroke amplification mechanism 30 can be arranged within the second rotating arm. The stroke amplification mechanism 30 includes a first driving part 31 and a second driving part 33. Figure 2 It is a schematic diagram of a variation of the joint assembly. Refer to Figure 2 , the first driving part 31 can move under the drive of the piezoelectric ceramic stack 50 and generate a displacement in the braking direction X. The second driving part 33 can be linked with the first driving part 31 and generate a displacement in the braking direction X, and the displacement generated by the second driving part 33 in the braking direction X is greater than the displacement generated by the first driving part 31 in the braking direction X.

[0048] The brake disk 40 can be arranged within the second rotating arm, and the brake disk 40 can be driven by the second driving part 33 to move between a braking position I as shown in Figure 2 and a release position II as shown in Figure 1 . Refer to Figure 2 , the brake disk 40 located at the braking position I can abut against the rotating disk 20, and prevent the rotating disk 20 from rotating through the generated frictional force. Refer to Figure 1 , the brake disk 40 located at the release position II can be separated from the rotating disk 20 and release it.

[0049] In the illustrative embodiment, refer to Figure 1 and Figure 2, the stroke amplification mechanism 30 includes a rotating rod 32. The rotating rod 32 is rotatably disposed within the second rotating arm about a first axis R2 (perpendicular to the paper plane in the figure) perpendicular to the braking direction X. The first driving portion 31 and the second driving portion 33 are respectively located on the rotating rod 32, and the distance between the first driving portion 31 and the first axis R2 is less than the distance between the second driving portion 33 and the first axis R2. The joint assembly further includes a first connecting rod 34 and a second connecting rod 36. Two ends of the first connecting rod 34 are respectively rotatably connected to the first driving portion 31 and one end of the piezoelectric ceramic stack 50 facing the brake disc 40 along the braking direction X about a rotation axis parallel to the first axis R2. Two ends of the second connecting rod 36 are respectively rotatably connected to the second driving portion 33 and the brake disc 40 about a rotation axis parallel to the first axis R2. Through the first connecting rod 34 and the second connecting rod 36, the piezoelectric ceramic stack 50, the rotating rod 32 and the brake disc 40 are linked. And through the rotating rod 32, in the braking direction X, the stroke of the piezoelectric ceramic stack 50 can be amplified on one side of the brake disc 40. However, it is not limited thereto. In other exemplary embodiments, the first connecting rod 34 and the second connecting rod 36 can be replaced by other structures, and the stroke amplification mechanism 30 can also be selected with other structures having the same function, such as a hydraulic stroke amplifier, etc.

[0050] The joint assembly provided by the present invention, by virtue of the characteristic that the piezoelectric ceramic stack 50 generates deformation under the inverse piezoelectric effect, amplifies the stroke through the stroke amplification mechanism 30 and drives the brake disc 40, and then stops the rotation of the rotating shaft 10 by the frictional force generated by the brake disc 40 against the rotating disc 20 fixed to the rotating shaft 10, thereby realizing the emergency braking function. The joint assembly provided by the present invention generates a driving force by the piezoelectric ceramic stack, has a faster action response, smaller volume and weight, and lower power consumption and operating temperature.

[0051] In the exemplary embodiment, referring to Figure 1 and Figure 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 on the side of the rotating disc 20 facing away from the brake disc 40 in the braking direction X. The rotating disc 20 includes a rotating disc body 22, several braking members 24 and several first driving members 26. The braking members 24 are movably disposed through the rotating disc body 22 between a contact position as shown in Figure 2 and a separation position as shown in Figure 1 along the braking direction X. Referring to Figure 2 , the braking member 24 located at the contact position can abut against the braking portion 60 and prevent the rotation of the rotating disc 20 by the frictional force. Referring to Figure 1, the brake member 24 located at the separation position can be separated from the braking portion 60. The first driving member 26 is an elastic cord, and each first driving member 26 applies a force to the rotating disk body 22 and a brake member 24 respectively and provides an elastic driving force for moving the brake member 24 towards the separation position. During the movement of the brake disk 40 from the release position II to the braking position I, it can overcome the elastic driving force of the first driving member 26 to drive the brake member 24 to move from the separation position to the contact position. During the movement of the brake disk 40 from the braking position I to the release position II, the brake member 24 can move from the contact position to the separation position under the elastic driving force of the first driving member 26. The brake disk 40 generates a frictional force for braking by pressing the brake member 24 against the braking portion 60, avoiding the axial force on the rotating disk body 22 and ensuring the stability of the rotating shaft 10. Although the first driving member 26 is an elastic cord in the illustrative embodiment, it is not limited thereto. In other illustrative embodiments, the first driving member 26 may also be other structures with the same function, such as a spring piece or a permanent magnet.

[0052] In the illustrative embodiment, a material with a high coefficient of friction is provided on the portion of the brake member 24 that contacts the braking portion 60, thereby increasing the frictional force between the brake member 24 and the braking portion 60 and improving the speed during braking.

[0053] Figure 3 is a schematic structural view of the rotating disk. Refer to Figure 3 , several brake members 24 are evenly arranged around the axis of the rotating disk body 22. Thereby, the frictional force generated by pressing the brake member 24 against the braking portion 60 can be evenly distributed on the rotating disk body 22, improving the stability during braking. Although the number of brake members 24 is six in the illustrative embodiment, it is not limited thereto. In other illustrative embodiments, the number of brake members 24 can be adjusted according to actual needs, and of course, it can also include only one brake member 24.

[0054] Figure 4 is a schematic structural view of another illustrative embodiment of the joint assembly. Refer to Figure 4 , which is the same as Figure 1The same or similar parts of the joint assemblies shown are not described again. The difference lies in that the first driving part 31 and the second driving part 33 are located on both sides of the first axis R2 in a direction perpendicular to the first axis R2 and the braking direction X, so that the first driving part 31 and the second driving part 33 generate reverse displacements in the braking direction X during the linkage process. In the illustrative embodiment, the joint assembly further includes a second driving member 70, which is a compression spring and applies forces to the second rotating arm and the brake disc 40 respectively to provide an elastic driving force for moving the brake disc 40 towards the braking position I. In use, after the piezoelectric ceramic stack 50 is powered on, it extends towards the brake disc 40 along the braking direction X and can overcome the elastic driving force of the second driving member 70 to drive the brake disc 40 to be in the release position II; after the electro-ceramic stack 50 is powered off, it retracts in the opposite direction of the braking direction X, and the brake disc 40 is driven by the elastic driving force of the second driving member 70 to move to the braking position I, whereby the joint assembly can automatically brake after being powered off. In other illustrative embodiments, the second driving member 70 can also be other components capable of providing driving force, such as a permanent magnet.

[0055] The present invention also provides a robot. Referring to Figure 1 , the robot includes a first rotating arm, a second rotating arm and a joint assembly as described above. The rotating shaft 10 is fixed to the first rotating arm, one end of the rotating shaft 10 extends into the second rotating arm, and is rotatably arranged in the second rotating arm around the axis of the rotating shaft 10. The rotating disc 20, the stroke amplification mechanism 30, the brake disc 40 and the piezoelectric ceramic stack 50 are arranged in the second rotating arm.

[0056] It should be understood that although this specification is described according to each embodiment, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0057] The series of detailed descriptions listed above are only specific descriptions of the feasible embodiments of the present invention, and they are not intended to limit the protection scope of the present invention. Any equivalent implementation or change made without departing from the technical spirit of the present invention, such as the combination, division or repetition of features, should be included in the protection scope of the present invention.

Claims

1. Joint assembly, characterized in that Comprising: 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 in the second rotating arm about the axis of the rotating shaft (10); A rotating disk (20) which can be fixed to the rotating shaft (10) within the second rotating arm; A piezoelectric ceramic stack (50) which can be arranged within the second rotating arm, and the piezoelectric ceramic stack (50) can generate a displacement in a telescopic direction through telescopic deformation; A stroke amplification mechanism (30) which can be arranged within the second rotating arm, and the stroke amplification mechanism (30) includes: A first driving part (31) which can move under the drive of the piezoelectric ceramic stack (50) and generate a 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 a displacement in the braking direction (X), and the displacement generated by the second driving part (33) in the braking direction (X) is greater than the displacement generated by the first driving part (31) in the braking direction (X); and A braking disk (40) which can be arranged within the second rotating arm, and can be driven by the second driving part (33) to move between a braking position (I) and a release position (II), wherein, the braking disk (40) located at the braking position (I) can abut against the rotating disk (20), and the braking disk (40) located at the release position (II) can be separated from the rotating disk (20), The joint assembly further includes a braking part (60) which is located on the side of the rotating disk (20) facing away from the braking disk (40) in the braking direction (X); The rotating disk (20) includes: A rotating disk body (22); A braking member (24) which is movably disposed through the rotating disk body (22) between a contact position and a separation position along the braking direction (X), the braking member (24) located at the contact position can abut against the braking part (60) and prevent the rotating disk (20) from rotating through friction, the braking member (24) located at the separation position can be separated from the braking part (60), and the braking disk (40) can drive the braking member (24) to move from the separation position to the contact position during the movement from the release position (II) to the braking position (I); and A first driving member (26) which applies forces to the rotating disk body (22) and the braking member (24) respectively and provides a driving force for making the braking member (24) move towards the separation position.

2. The joint assembly according to claim 1, characterized in that The rotating disk (20) has a plurality of the braking members (24), and the plurality of braking members (24) are uniformly arranged around the axis of the rotating disk body (22).

3. The joint assembly according to claim 1, characterized in that The part of the braking member (24) in contact with the braking part (60) is provided with a material with a high friction coefficient.

4. The joint assembly according to claim 1, characterized in that The braking part (60) is the housing of the second rotating arm.

5. The joint assembly according to claim 1, characterized in that The stroke amplification mechanism (30) includes a rotating rod (32) rotatably arranged in the second rotating arm around a first axis (R2) perpendicular to the braking direction (X). 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 less than the distance between the second driving part (33) and the first axis (R2).

6. The joint assembly according to claim 5, characterized in that The joint assembly further includes: A first connecting rod (34) whose two ends are respectively rotatably connected to the first driving part (31) and one end of the piezoelectric ceramic stack (50) along the braking direction (X) around a rotation axis parallel to the first axis (R2); and A second connecting rod (36) whose two ends 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).

7. The joint assembly according to claim 5, characterized in that The telescopic direction is parallel to the braking direction (X). After being energized, the piezoelectric ceramic stack (50) extends towards the brake disc (40) along the braking direction (X), and retracts in the opposite direction of the braking direction (X) after being powered off.

8. The joint assembly according to claim 7, characterized in that The first driving part (31) and the second driving part (33) are located on both sides of the first axis (R2) in a direction perpendicular to the first axis (R2) and the braking direction (X), so that the first driving part (31) and the second driving part (33) generate reverse displacements in the braking direction (X) during the linkage process; the joint assembly further includes a second driving member (70) that respectively applies forces to the second rotating arm and the brake disc (40) and provides a driving force for the brake disc (40) to move towards the braking position (I).

9. The joint assembly according to claim 8, characterized in that The second driving member (70) is a spring that respectively applies forces to the second rotating arm and the brake disc (40) and provides an elastic driving force for the brake disc (40) to move towards the braking position (I).

10. A robot, characterized in that Comprising: A first rotating arm; A second rotating arm; And A joint assembly according to any one of claims 1 to 9, wherein the rotating shaft (10) is fixed to the first rotating arm, one end of the rotating shaft (10) extends into the second rotating arm, and is rotatably arranged in the second rotating arm around the axis of the rotating shaft (10). The rotating disc (20), the stroke amplification mechanism (30), the brake disc (40) and the piezoelectric ceramic stack (50) are arranged in the second rotating arm.

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