Protective mechanism for a robot arm joint

Abstract

The application discloses a protection mechanism of a mechanical arm joint, which comprises a base, a connecting seat, a sensor and an elastic piece, a guide assembly is used for limiting the movement track of the connecting seat on the base; the sensor is used for detecting the relative displacement between the connecting seat and the base on the movement track; the elastic piece acts on the connecting seat and keeps the connecting seat in a first working position; wherein under the action of an external force, the connecting seat can move to a second working position relative to the base and make the elastic piece accumulate energy; after the external force is removed, the connecting seat can move to the first working position from the second working position under the action of the elastic piece. The protection mechanism can ensure that the workpiece can be closely attached to the anvil or the workpiece when the mechanical arm drives the workpiece to process, and avoid that the adverse external force caused by the movement of the workpiece due to the gap in the processing process acts on the joint of the mechanical arm or / and the servo motor, thereby avoiding that the joint of the mechanical arm or / and the servo motor is damaged due to the overload caused by the external force.

Description

Technical Field

[0001] This application relates to a protective mechanism for a robotic arm joint. Background Technology

[0002] Robotic arms are widely used in modern processing, such as for operations like spot welding, riveting, stamping, and punching.

[0003] However, some problems may arise during actual processing. If the workpiece held by the robotic arm has its own errors, or if there are errors in the movement of the robotic arm, the workpiece may not be able to fit tightly against the anvil of the processing equipment, or there may be gaps between multiple workpieces. Processing under these circumstances will inevitably cause the free end of the robotic arm to move. Although the distance of this movement may not be large, it has a significant destructive force on the precision joints of the robotic arm and the servo motors that drive the joints, and may very likely cause damage to the joints of the robotic arm or the servo motors. Utility Model Content

[0004] This application provides a protective mechanism for a robotic arm joint, which addresses at least one technical problem in the prior art.

[0005] A protective mechanism for a robotic arm joint includes: a base configured to be connected to the free end of the robotic arm; a connecting seat movably connected to the base via a guide assembly, the guide assembly being used to limit the movement trajectory of the connecting seat on the base; a sensor for detecting the relative displacement between the connecting seat and the base on the movement trajectory; and an elastic element acting on the connecting seat and holding the connecting seat in a first working position; wherein, under the action of an external force, the connecting seat can move relative to the base to a second working position and cause the elastic element to undergo elastic deformation; after the external force is removed, the connecting seat can move from the second working position to the first working position under the drive of the elastic element.

[0006] In some embodiments, the guide assembly includes a first guide disposed on the connecting seat and a second guide disposed on the base, the first guide and the second guide being slidably connected.

[0007] In some implementations, the guiding component includes a linear guiding mechanism.

[0008] In some embodiments, the first guide member includes a guide hole; the second guide member includes a guide rod, at least one end of which is connected to the base, the guide rod passing through the guide hole and slidingly engaging with the guide hole; the first end of the elastic member is connected to the connecting seat, and the second end of the elastic member is connected to the base or the guide rod.

[0009] In some embodiments, the base is provided with a groove, and the connecting seat is disposed in the groove; the elastic element includes a helical spring, which is sleeved on the outside of the guide rod, and the first end of the helical spring acts on the connecting seat, and the second end acts directly or indirectly on the base.

[0010] In some implementations, a linear bearing is provided in the guide hole, and the guide rod slides in conjunction with the linear bearing.

[0011] In some implementations, a bushing is provided inside the guide hole, and the guide rod slides in conjunction with the bushing.

[0012] In some embodiments, a retaining device is mounted on the connector, the retaining device being configured to selectively restrain the workpiece on the protective mechanism.

[0013] In some implementations, the sensor is mounted on the base or the connector.

[0014] In some implementations, the sensor and the object being detected are respectively disposed on the base and the connecting seat.

[0015] Compared with existing technologies, this application has the advantage that its protection mechanism ensures a tight fit between the workpiece and the anvil or other workpiece when the robotic arm drives the workpiece for processing. This prevents adverse external forces caused by workpiece movement due to gaps during processing from acting on the joints and / or servo motors of the robotic arm, thereby preventing damage to the joints and / or servo motors due to overload caused by external forces and extending the service life of the robotic arm. Furthermore, this application's protection mechanism is adaptable to various types of holding devices, broadening its application range. Thirdly, after the tight fit between the workpiece and the anvil or other workpiece is confirmed, the workpiece enters the processing step. During processing, the workpiece may deform under the action of force (such as punching force). This application's protection mechanism can adapt to this deformation, thereby eliminating or reducing the adverse effects of this deformation on the joints and / or servo motors of the robotic arm. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. Wherein:

[0017] Figure 1 This is a schematic diagram of one application scenario in the embodiments of this application;

[0018] Figure 2 for Figure 1A magnified view of part A in the diagram;

[0019] Figure 3 This is a schematic diagram of the structure of one type of holding device in an embodiment of this application;

[0020] Figure 4 This is a schematic diagram showing the separated state of the retaining device and the protection mechanism in the embodiments of this application;

[0021] Figure 5 This is an exploded view of the protection mechanism in the embodiments of this application;

[0022] Figure 6 This is a schematic diagram from another perspective of the protection mechanism in the embodiments of this application;

[0023] Figure 7 for Figure 6 Sectional view along the CC direction;

[0024] Figure 8 for Figure 3 A magnified view of a portion of point B in the middle;

[0025] Figure 9 for Figure 8 Another state diagram;

[0026] Figure 10 This is a schematic diagram of another embodiment of the protective structure in this application;

[0027] Figure 11 for Figure 10 Sectional view along the DD direction;

[0028] Figure 12 This is a schematic diagram illustrating another application scenario in the embodiments of this application.

[0029] Explanation of reference numerals in the attached figures:

[0030] 100 - Holding device;

[0031] 10-Protective mechanism; 101-Base; 1011-First side plate; 1012, 1012a-Second side plate; 1013-Third side plate; 1014-Receiving groove; 102-Connecting seat; 1021, 1021a-Guide hole; 1031-Photoelectric sensor; 1032-Light shield; 1033-Optical path; 104-Guide assembly; 1041, 1041a-Guide rod; 1042-Linear bearing; 1043-Fixing bolt; 1044-Washer; 105-Helical spring; 11-Retaining device; 111-Clamp;

[0032] 200 - Robotic arm; 201 - Free end; 200a - First robotic arm; 200b - Second robotic arm;

[0033] 300 - Processing equipment; 301 - Anvil; 302 - Pressure head;

[0034] 400 - Workpiece. Detailed Implementation

[0035] The present application will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation and not by way of limitation. In fact, those skilled in the art will recognize that modifications and variations can be made to the present application without departing from the scope or spirit thereof. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present application encompass such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0036] In the description of this application, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and do not require that this application be constructed and operated in a specific orientation, and therefore should not be construed as limiting this application. The terms "connected," "linked," and "set up" used in this application should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; direct connections or indirect connections through intermediate components; wired connections, radio connections, or wireless communication signal connections. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0037] The accompanying drawings illustrate one or more examples of this application. The detailed description uses numerical and alphabetic designations to refer to features in the drawings. Similar or analogous designations in the drawings and description have been used to refer to similar or analogous parts of this application. As used herein, the terms “first,” “second,” and “third,” etc., are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of individual components.

[0038] like Figure 1 and Figure 2As shown, in one workpiece processing scenario, the free end 201 of the robotic arm 200 is connected to a workpiece holding device 100, which can move the workpiece 400 to a predetermined position on the processing equipment 300. As described in the background section of this application, when the robotic arm 200 places the workpiece 400 above the anvil 301 (the anvil in this embodiment is for illustrative purposes only and not a specific limitation), the fit between the workpiece 400 and the anvil 301 may not be tight enough due to various reasons. When the pressure head 302 of the processing equipment 300 processes (e.g., punching) the workpiece 400, the workpiece 400 will move, and this movement will be transmitted to the robotic arm 200 through the holding device 100. In order to keep the workpiece 400 stationary, the joints and servo motors of the robotic arm 200 need to bear the energy transmitted by the movement, and this energy is very likely to cause the joints and / or servo motors of the robotic arm 200 to be damaged due to overload; or due to the superposition of this situation, the service life of the joints and / or servo motors of the robotic arm 200 is shortened.

[0039] To ensure that the workpiece 400 fits tightly against the anvil 301 during processing, this application provides a holding device 100 installed at the free end 201 of the robotic arm 200. For example... Figure 3 and Figure 4 As shown, the holding device 100 includes a protection mechanism 10 and a holding device 11. The protection mechanism 10 includes a base 101, a connecting seat 102, a guide assembly 104, and an elastic element. The connecting seat 102 is movably connected to the base 101 via the guide assembly 104, which constrains the movement trajectory of the connecting seat 102 on the base 101. The elastic element provides support to the connecting seat 102 in a first direction D1, allowing the connecting seat 102 to remain relatively stationary with respect to the base 101 without external force; at this point, the connecting seat 102 is in a first working position. The protection mechanism 10 also includes a sensor for acquiring the relative displacement between the connecting seat 102 and the base 101. In application, the sensor is connected to the controller of the robotic arm, which can be integrated into the robotic arm or mounted on a separate industrial computer; no specific limitations are imposed here. Of course, the holding device and processing equipment can also be controlled by the controller. The holding device 11 is fixedly connected to the connecting seat 102, and the base 101 is mounted on the free end 201 of the robotic arm 200.

[0040] In the embodiments of this application, the holding device 11 is a clamp 111, which can be pneumatically or electrically driven. The workpiece 400 is constrained on the holding device 100 by the clamp 111. In addition to the clamping method, the holding device 11 can also be implemented in other ways, such as vacuum adsorption, electromagnetic adsorption, etc., without specific limitations here.

[0041] In one application scenario, the robotic arm 200 drives the holding device 100 to move the workpiece 400 above the anvil 301 according to a preset program, and then moves the workpiece 400 toward the anvil 301. The direction toward the anvil 301 is the same as the first direction D1 and the direction of force applied to the workpiece 400 during processing. After the workpiece 400 comes into contact with the anvil 301, the robotic arm 200 continues to apply force to the holding device 100 along the first direction D1. Because the workpiece 400 is restricted by the anvil 301, the connecting seat 102 and the holding device 11 cannot move in the first direction D1. Since the connecting seat 102 is movably connected to the base 101 through the guide assembly 104, the force applied by the robotic arm 200 to the holding device 100 allows the base 101 to continue moving along the first direction D1. At this time, a relative displacement X begins between the connecting seat 102 and the base 101, and the elastic element undergoes elastic deformation. Once the displacement X detected by the sensor reaches a preset value, the robotic arm 200 stops moving, and the current connecting seat 102 is in the second working position. At this time, the contact state between the workpiece 400 and the anvil 301 is confirmed, and the system enters the next processing step.

[0042] During the processing, the workpiece 400 may deform under the action of force (such as punching force). This deformation is also detrimental to the robotic arm 200. The protection mechanism 10 of this application can adapt to this deformation, thereby eliminating or weakening the adverse effects of this deformation on the joints and / or servo motors of the robotic arm 200. For example, in conjunction with the above embodiment, the direction of the external force on the workpiece 400 during processing is the same as the first direction D1. Assuming that the workpiece 400 deforms in the first direction D1, since the workpiece 400 is in the second working position, the elastic element can drive the connecting seat 102 to move in the first direction D1, thereby compensating for the deformation of the workpiece 400 and ensuring the state of the workpiece 400 on the processing equipment 300. If the workpiece 400 deforms in the second direction D2, the workpiece 400 pushes the connecting seat 102 to move in the second direction D2, and the elastic element can be further compressed, thereby compensating for the deformation of the workpiece 400 and ensuring the state of the workpiece 400 on the processing equipment 300.

[0043] After processing is completed, the robotic arm 200 drives the holding device 100 to remove the workpiece 400 from the anvil 301. For example, the holding device 100 can move in a second direction D2 away from the first direction D1. Since the connecting seat 102 and the base 101 have undergone relative displacement X during the preceding process, and the elastic element has accumulated elastic force during elastic deformation, when the holding device 100 moves in the second direction D2, the relative displacement X between the connecting seat 102 and the base 101 is reduced to 0 under the combined force of the elastic force of the elastic element and external forces (such as gravity), that is, the connecting seat 102 moves from the second working position to the first working position. During this process, the workpiece 400 remains in contact with the anvil 301. When the holding device 100 continues to move in the second direction D2 under the drive of the robotic arm 200, the workpiece 400 will completely disengage from the anvil 301.

[0044] The direction of the elastic force and the direction of the external force may be the same or different, but the resultant force of the elastic force and the external force can still push the connector to move and reduce the relative displacement X between the connector 102 and the base 101 to 0.

[0045] like Figures 4 to 7 As shown, this application provides an embodiment 1 of a protective mechanism 10. The base 101 includes a first side plate 1011 and a second side plate 1012 and a third side plate 1013 disposed at both ends of the first side plate 1011. The first side plate 1011, the second side plate 1012, and the third side plate 1013 form a receiving groove 1014. The connecting seat 102 is movably disposed within the receiving groove 1014. The guide assembly 104 includes a guide hole 1021 disposed in the connecting seat 102 and a guide rod 1041. The guide hole 1021 extends between the second side plate 1012 and the third side plate 1013. The guide rod 1041 passes through the guide hole 1021 and is slidably connected to the guide hole 1021. The first end of the guide rod 1041 is connected to the second side plate 1012 by a fixing bolt 1043, and the second end of the guide rod 1041 is connected to the third side plate 1013 by a fixing bolt 1043. In the embodiments of this application, two guide holes 1021 are provided, and the two guide holes 1021 are parallel to each other. The spring component includes a helical spring 105, which is disposed in the receiving groove 1014 and sleeved on the guide rod 1041. The first end of the helical spring 105 acts on the third side plate 1013, and the second end acts on the connecting seat 102.

[0046] During assembly, in order to ensure that the connecting seat 102 remains relatively stationary with the base 101 under the support of the helical spring 105 in the initial state, a suitable helical spring 105 can be selected to provide sufficient support force; or, a shim 1044 can be fitted on the guide rod 1041 between the helical spring 105 and the third side plate 1013 or / and between the helical spring 105 and the connecting seat 102 or / and between the connecting seat 102 and the second side plate 1012, and the compression degree of the helical spring 105 can be adjusted by the number and / or thickness of the shims 1044, thereby adjusting the magnitude of the force exerted by the helical spring 105 on the connecting seat 102.

[0047] like Figure 7 and Figure 8 As shown, in some embodiments, the sensor includes a slotted photoelectric sensor 1031, which is disposed on the second side plate 1012; the detected object includes a light-shielding sheet 1032, which is disposed on the connecting seat 102. Figure 8 and Figure 9 As shown, when a relative displacement occurs between the base 101 and the connecting seat 102, the light-shielding plate 1032 blocks the optical path 1033 (schematic) of the photoelectric sensor 1031. In conjunction with the above embodiment, the robotic arm 200 can perform corresponding actions based on the changes in the optical path 1033 fed back by the photoelectric sensor 1031. The sensor selected in this embodiment, as well as the position of the sensor and the object being detected and the detection method, are only one example. Different types of sensors can be selected according to different needs. The types of sensors include, but are not limited to, acoustic, optical, and electrical sensors, or contact and non-contact sensors. The sensor can also be installed at a suitable position depending on different circumstances. Furthermore, the object being detected (such as the light-shielding plate 1032 in the embodiment) also includes the connecting seat 102 or the base 101 itself; no specific limitations are made here.

[0048] like Figure 5 and Figure 7As shown, in some embodiments, the connecting seat 102 and the guide rod 1041 are connected by a linear bearing 1042. In this embodiment, the linear bearing 1042 is installed in the guide hole 1021. The linear bearing 1042 makes the sliding connection between the connecting seat 102 and the guide rod 1041 smoother. In addition, in some embodiments, the linear bearing 1042 in the guide hole 1021 can be replaced by a bushing, which includes, but is not limited to, composite bushings, self-lubricating bushings, etc., without specific limitations. Furthermore, in some embodiments, the linear guide assembly formed by the linear bearing 1042 / shoulder and the guide rod 1041 can be replaced by a linear guide rail structure. The guide rod 1041 in the above embodiments is a form of guide rail, and the connecting seat 102 is equipped with a slider that slides with the guide rod 1041 (guide rail). Of course, the slider can also be replaced by a groove provided on the connecting seat 102, which slides with the guide rod 1041 (guide rail).

[0049] like Figure 10 and Figure 11 As shown, this application provides a second embodiment of the protection mechanism 10. The base 101 includes a first side plate 1011 and a second side plate 1012a disposed on the first side plate 1011. The first end of the guide rod 1041a is mounted on the second side plate 1012a by a fastening bolt, and the guide hole 1021a of the connecting seat 102 is slidably engaged with the guide rod 1041a. A helical spring 105 is sleeved on the second end of the guide rod 1041a, and the helical spring 105 and the connecting seat 102 are constrained on the base 101 by the fastening bolt at the second end of the guide rod 1041a. The principle of this embodiment is the same as that of the first embodiment of the protection structure, and will not be described again here.

[0050] Figure 12 Another application scenario is provided, where the free ends 201 of both robotic arms 200 are equipped with the holding devices 100 of this application. The first robotic arm 200a uses the holding devices 100 to place the first workpiece above the anvil 301, ensuring a tight fit between the first workpiece and the anvil 301; the second robotic arm 200b uses the holding devices 100 to place the second workpiece above the first workpiece, ensuring a tight fit between the second and first workpieces.

[0051] The holding device 100 of this application does not limit the direction of processing. The above embodiments are only examples. In application, the first direction D1 relative to the ground can be vertical, horizontal, or tilted at any angle. The first direction D1 is the same as the direction of force on the workpiece during processing.

[0052] The above descriptions are merely examples of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A protective mechanism for a robotic arm joint, characterized in that, include: A base (101) is configured to be connected to the free end (201) of the robotic arm (200). A connecting seat (102) is movably connected to the base (101) via a guide assembly (104), the guide assembly (104) being used to limit the movement trajectory of the connecting seat (102) on the base (101); Sensor, the sensor being used to detect the relative displacement between the connecting seat (102) and the base (101) on the motion trajectory; and An elastic element acts on the connecting seat (102) and holds the connecting seat (102) in a first working position; Under the action of external force, the connecting seat (102) can move relative to the base (101) to the second working position and cause the elastic element to undergo elastic deformation; after the external force is removed, the connecting seat (102) can move from the second working position to the first working position under the drive of the elastic element.

2. The protection mechanism according to claim 1, characterized in that, The guide assembly (104) includes a first guide member disposed on the connecting seat (102) and a second guide member disposed on the base (101), the first guide member and the second guide member being slidably connected.

3. The protection mechanism according to claim 2, characterized in that, The guide assembly (104) includes a linear guide mechanism.

4. The protection mechanism according to claim 3, characterized in that, The first guide includes guide holes (1021, 1021a). The second guide member includes guide rods (1041, 1041a), at least one end of which is connected to the base (101), and the guide rods (1041, 1041a) pass through the guide holes (1021, 1021a) and slide in cooperation with the guide holes (1021, 1021a). The first end of the elastic element is connected to the connecting seat (102), and the second end of the elastic element is connected to the base (101) or the guide rod (1041, 1041a).

5. The protection mechanism according to claim 4, characterized in that, The base (101) is provided with a receiving groove (1014), and the connecting seat (102) is disposed in the receiving groove (1014); The elastic element includes a helical spring (105), which is sleeved on the outside of the guide rod (1041, 1041a). The first end of the helical spring (105) acts on the connecting seat (102), and the second end acts directly or indirectly on the base (101).

6. The protection mechanism according to claim 4, characterized in that, A linear bearing (1042) is provided inside the guide hole (1021), and the guide rod (1041) is slidably engaged with the linear bearing (1042); or A bushing is provided inside the guide hole (1021), and the guide rod (1041) slides with the bushing.

7. The protection mechanism according to claim 1, characterized in that, A retaining device (11) is mounted on the connecting seat (102), the retaining device being configured to selectively restrain the workpiece on the protective mechanism.

8. The protection mechanism according to claim 1, characterized in that, The sensor is mounted on the base (101) or the connector (102).

9. The protection mechanism according to claim 8, characterized in that, It also includes the object to be detected, and the sensor and the object to be detected are respectively disposed on the base (101) and the connecting seat (102).

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