Mechanical joint, mechanical arm and cleaning equipment

Abstract

The utility model provides a mechanical joint, a mechanical arm and cleaning equipment. The mechanical joint comprises a connecting frame and a lifting assembly, the connecting frame is hinged to a base of the mechanical arm, the lifting assembly comprises a nut, a lead screw and a driving part, the nut and the lead screw are connected through non-self-locking threads and hinged to the base, the driving part is arranged on the connecting frame, the first end of the lead screw is connected with the driving part, and the second end of the lead screw penetrates through the nut; the driving part is used for driving the lead screw to rotate, so that the lead screw and the nut move relatively to drive the connecting frame to ascend or descend relative to the base. Therefore, lifting and falling operation of the mechanical joint can be achieved, and after the mechanical joint is accidentally powered off in the lifting state, the connecting frame can fall relative to the base by applying external force to the mechanical joint so as to meet the requirement for folding and storage of the mechanical arm.

Description

Technical Field

[0001] The utility model relates to the technical field of smart home, and particularly relates to a mechanical joint, a robotic arm and a cleaning device. Background Art

[0002] With the continuous development of science and technology and the continuous improvement of people's living standards, cleaning devices, such as intelligent floor sweeping robots, have continuously entered our daily lives. At present, in order to better achieve the cleaning function, existing cleaning devices are equipped with robotic arms with mechanical hands to grab or move obstacles, items, and garbage by using the mechanical hands. Summary of the Utility Model

[0003] A series of simplified concepts are introduced in the summary of the utility model, which will be further described in detail in the specific implementation section. This section of the utility model does not mean to attempt to define the key features and essential technical features of the claimed technical solution, nor does it mean to attempt to determine the protection scope of the claimed technical solution.

[0004] In a first aspect of the utility model, a mechanical joint for a robotic arm is provided. The mechanical joint includes: a connecting frame and a lifting assembly. The connecting frame is hinged to the base of the robotic arm. The lifting assembly includes a nut, a lead screw, and a driving part. The nut is connected to the lead screw by a non-self-locking thread and is hinged to the base. The driving part is arranged on the connecting frame. The first end of the lead screw is connected to the driving part, and the second end of the lead screw passes through the nut; wherein, the driving part is used to drive the lead screw to rotate, so that the lead screw and the nut move relative to each other to drive the connecting frame to lift or lower relative to the base.

[0005] Further, the lead screw is provided with an external thread structure, and the thread lead angle of the external thread structure is greater than the equivalent friction angle of the thread pair composed of the lead screw and the nut.

[0006] Further, the lead screw is made of steel, copper, or copper alloy; the nut is made of steel, copper, or copper alloy.

[0007] Further, the pitch diameter of the external thread structure is 3 mm to 6 mm, and the lead of the external thread structure is 2.5 mm to 5.5 mm.

[0008] Further, the lifting assembly further includes: a motor bracket, the motor bracket is hinged to the connecting frame, the driving part is installed on the motor bracket, and the lead screw passes through the motor bracket and is connected to the driving part.

[0009] Further, the lifting assembly further includes: a rotating part, the rotating part is sleeved outside the lead screw, the lead screw is provided with a stepped structure, and the rotating part is located between the stepped structure and the motor bracket to enable the lead screw and the motor bracket to be rotatably connected.

[0010] Further, first cylindrical bosses are provided on opposite sides of the outer wall of the nut, and a first receiving groove is formed in the base. The first cylindrical bosses are received in the first receiving groove and can rotate within the first receiving groove.

[0011] Further, second cylindrical bosses are provided on opposite sides of the motor bracket, and a second receiving groove is formed in the connecting frame. The second cylindrical bosses are received in the second receiving groove and can rotate within the second receiving groove.

[0012] Further, the mechanical joint further includes: a connecting shaft, the axis of the connecting shaft is arranged parallel to the axis of the first cylindrical boss and is connected to the base; the end of the connecting frame close to the base is sleeved outside the connecting shaft and is rotatably connected to the connecting shaft.

[0013] Further, a connecting ring is provided at the end of the connecting frame close to the base, and the connecting ring is sleeved outside the connecting shaft; the mechanical joint further includes a connecting bearing connected between the connecting ring and the connecting shaft.

[0014] In a second aspect of the present utility model, a robotic arm is provided, including: the mechanical joint according to any one of the first aspect.

[0015] In a third aspect of the present utility model, a cleaning device is provided, including: the robotic arm according to any one of the second aspect.

[0016] The mechanical joint, robotic arm and cleaning device provided by the embodiments of the present utility model, the mechanical joint includes a connecting frame and a lifting assembly. The connecting frame is hinged to the base, so that the connecting frame can rotate relative to the base; the lifting assembly includes a nut, a lead screw and a driving part. The nut and the lead screw are connected by a threaded structure. By the operation of the driving part, the lead screw rotates, so that the nut and the lead screw can move relative to each other. Since the nut is hinged to the base and the driving part is arranged on the connecting frame, the lead screw can move relative to the nut in a direction close to or away from the base, and then the connecting frame can be lifted or lowered relative to the base to meet the requirements of different functions such as the operation or storage of the robotic arm. Among them, since the nut and the lead screw are connected by a non-self-locking thread, in this way, when the mechanical joint is accidentally powered off in the lifted state, by applying an external force to the mechanical joint, the connecting frame can be lowered relative to the base to meet the requirement of folding and storing the robotic arm, avoiding the problem that the lifting assembly of the mechanical joint in the related art cannot be lowered and always remains in the lifted state after being accidentally powered off in the lifted state, which makes the robotic arm occupy a large space, affects the moving range of the cleaning device and is not convenient for storage, greatly improving the operability of the mechanical joint and enhancing the user experience.

[0017] The above description is only an overview of the technical solution of the present application. In order to be able to understand the technical means of the present application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other objects, features and advantages of the present application more obvious and understandable, the specific embodiments of the present application are hereinafter specifically exemplified. Brief Description of the Drawings

[0018] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present utility model. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. Among them:

[0019] Figure 1 Fig. shows a perspective three-dimensional structural schematic diagram of the robotic arm of the present utility model;

[0020] Figure 2 Fig. shows a structural schematic diagram of a perspective view of the mechanical joint at the robotic arm of the present utility model in a raised state;

[0021] Figure 3 Fig. shows a partial structural schematic diagram of the mechanical joint at the mechanical part of the present utility model in a raised state;

[0022] Figure 4 Fig. shows another partial structural schematic diagram of the mechanical joint at the mechanical part of the present utility model in a raised state;

[0023] Figure 5 Fig. shows Figure 4 a partial enlarged schematic diagram of location A of the illustrated embodiment;

[0024] Figure 6 Fig. shows a schematic diagram of the force on the mechanical joint when the robotic arm returns to the bin;

[0025] Figure 7 Fig. shows a schematic diagram of the force on the mechanical joint when the robotic arm is held in the working position;

[0026] Figure 8 Fig. shows a structural schematic diagram of a perspective view of the mechanical joint at the robotic arm of the present utility model in a lowered state;

[0027] Figure 9 Fig. shows a partial structural schematic diagram of the mechanical joint of the robotic arm of the present utility model in a lowered state;

[0028] Figure 10 Fig. shows Figure 9 a partial enlarged schematic diagram of location B of the illustrated embodiment;

[0029] Figure 11 Fig. shows a schematic diagram of the force on the mechanical joint when the robotic arm exits the bin;

[0030] Figure 12 Fig. shows a structural schematic diagram of a perspective view of the base of the robotic arm of the present utility model;

[0031] Figure 13 The partial structural schematic diagram of the lifting assembly of the present utility model is shown;

[0032] Figure 14 The structural schematic diagram of a perspective of the cleaning device of the present utility model is shown.

[0033] Among them, Figures 1 to 14 The corresponding relationship between the reference numerals and the component names in the figure is as follows:

[0034] 100 mechanical joint, 110 connecting frame, 111 connecting ring, 120 lifting assembly, 121 nut, 1211 first cylindrical boss, 122 lead screw, 1221 external thread structure, 123 driving part, 124 motor bracket, 1241 second cylindrical boss, 125 rotating part, 130 connecting shaft, 140 connecting bearing, 200 robotic arm, 210 slewing joint, 211 base, 2111 first receiving groove, 2112 mounting hole, 220 fixed seat, 230 first flipping joint, 240 second flipping joint, 250 robotic hand, 300 cleaning device, 310 main body. Specific embodiments

[0035] In the following description, a large number of specific details are given to provide a more thorough understanding of the technical solutions provided by the present utility model. However, it is obvious to those skilled in the art that the technical solutions provided by the present utility model can be implemented without one or more of these details.

[0036] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present utility model. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, they specify the presence of the described features, wholes, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or combinations thereof.

[0037] Now, the exemplary embodiments according to the present utility model will be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many different forms and should not be construed as being limited only to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of the present utility model is thorough and complete, and the concept of these exemplary embodiments is fully conveyed to those of ordinary skill in the art.

[0038] As Figures 1 to 14As shown in the figure, an embodiment of the first aspect of the present utility model provides a mechanical joint 100, an embodiment of the second aspect of the present utility model provides a robotic arm 200, and an embodiment of the third aspect of the present utility model provides a cleaning device 300. Among them, the mechanical joint 100 is applied to the robotic arm 200, and the robotic arm 200 is applied to the cleaning device 300. The cleaning device 300 can be a floor sweeping robot, a mopping and sweeping integrated machine, or other cleaning robots that meet the requirements.

[0039] As Figure 14 shown, the cleaning device 300 includes but is not limited to: a main body 310, a drive system, a cleaning system, etc. The above-mentioned various systems cooperate with each other to enable the cleaning device 300 to move autonomously to achieve the cleaning function. The functional elements and the like that make up the above-mentioned various systems in the cleaning device 300 are integrally arranged in the main body 310. It can be understood that the cleaning device 300 can be a self-moving cleaning device. A self-moving cleaning device is a device that automatically performs cleaning operations in a certain area to be cleaned without the operation of a user.

[0040] Furthermore, as Figure 14 shown, the robotic arm 200 is applied to the cleaning device 300. For example, the robotic arm 200 is connected to the main body 310 of the cleaning device 300 to use the manipulator 250 at the end of the robotic arm 200 to grasp or move obstacles, objects, and garbage near the cleaning device 300, so as to better achieve the autonomous cleaning function.

[0041] Among them, as Figure 1 , Figure 2 , Figure 3 , Figure 8 and Figure 9 shown, when the robotic arm 200 is in the working state, some of the mechanical joints 100 need to be kept in the lifted state so that the manipulator 250 at the end of the robotic arm 200 can reach the appropriate position for grasping or placing objects. When the robotic arm 200 is in the non-working state, the lifted mechanical joints 100 need to descend so that the robotic arm 200 is in the folded and retracted state for storage.

[0042] As Figure 2 , Figure 3 , Figure 8 and Figure 9As shown in the figure, an embodiment of the first aspect of the present utility model provides a mechanical joint 100 for a robotic arm 200. The mechanical joint 100 includes a connecting frame 110 and a lifting assembly 120. The connecting frame 110 is hinged to the base 211 of the robotic arm 200. The lifting assembly 120 includes a nut 121, a lead screw 122, and a driving portion 123. The nut 121 is connected to the lead screw 122 by a non-self-locking thread and is hinged to the base 211. The driving portion 123 is disposed on the connecting frame 110. The first end of the lead screw 122 is connected to the driving portion 123, and the second end of the lead screw 122 passes through the nut 121 and is disposed toward the base 211. Wherein, the driving portion 123 is used to drive the lead screw 122 to rotate, so that the lead screw 122 and the nut 121 move relative to each other to drive the connecting frame 110 to lift or lower relative to the base 211.

[0043] Wherein, the base 211 of the robotic arm 200 can be a structure for the robotic arm 200 to connect to the main body 310 of the cleaning device 300, or can be a part of the structure of other joints of the robotic arm 200.

[0044] The mechanical joint 100 provided by the embodiment of the present utility model includes a connecting frame 110 and a lifting assembly 120. The connecting frame 110 is hinged to the base 211, so that the connecting frame 110 can rotate relative to the base 211. The lifting assembly 120 includes a nut 121, a lead screw 122, and a driving portion 123. The nut 121 and the lead screw 122 are connected by a threaded structure. By the operation of the driving portion 123 to drive the lead screw 122 to rotate, the nut 121 and the lead screw 122 can move relative to each other. Since the nut 121 is hinged to the base 211 and the driving portion 123 is disposed on the connecting frame 110, the lead screw 122 can move relative to the nut 121 in a direction close to or away from the base 211, and thus the connecting frame 110 can lift or lower relative to the base 211. Therefore, the lifting and lowering of the mechanical joint 100 can be realized to meet the needs of the robotic arm 200 to lift to different heights and positions during work to meet the needs of clamping operations, and can meet the requirement of the robotic arm 200 to lower to a folded state for storage when not working. Wherein, since the nut 121 and the lead screw 122 are connected by a non-self-locking thread, in this way, when the mechanical joint 100 is accidentally powered off in the lifted state, by applying an external force to the mechanical joint 100, such as applying an external force to the connecting frame 110, the lead screw 122 and the nut 121 can move relative to each other to drive the connecting frame 110 to lower relative to the base 211. Therefore, the requirement of folding and storing the robotic arm 200 can be met, avoiding the problem that in the related art, after the mechanical joint is accidentally powered off in the lifted state, the lifting assembly cannot lower and always remains in the lifted state, resulting in a large space occupied by the robotic arm, affecting the moving range of the cleaning device and being inconvenient for storage. The operability of the mechanical joint 100 is greatly improved, the operability of the robotic arm 200 is improved, and the user experience is enhanced.

[0045] It can be understood that, as Figure 2 and Figure 3 shown, when the connecting frame 110 is lifted relative to the base 211 to the unfolded state, that is, when the robotic joint 100 is lifted relative to the base 211 to the unfolded state, such as when the connecting frame 110 of the robotic joint 100 is lifted and unfolded to the vertical position, the robotic arm 200 can be unfolded and in the working state. As Figure 8 and Figure 9 shown, when the connecting frame 110 descends relative to the base 211 to the folded state, that is, when the robotic joint 100 descends relative to the base 211 to the folded state, such as when the connecting frame 110 of the robotic joint 100 is in the horizontal position, the robotic arm 200 can be in the folded storage position and not working, so as to reduce the space occupied by the robotic arm 200. Among them, by the cooperation of the driving part 123, the lead screw 122 and the nut 121, the lifting or descending operation of the robotic joint 100 relative to the base 211 can be realized, with a simple structure and convenient operation, and can meet the design requirements of the robotic arm 200 with a compact structure and a small volume.

[0046] Furthermore, when the robotic joint 100 is lifted to the unfolded state, that is, when the robotic arm 200 is in the working state, by powering on the driving part 123, the robotic joint 100 can be kept in the lifted state against the working load. It can be understood that the torque provided by the driving part 123 in this posture can be associated with the working load, so that the robotic joint 100 can resist the working load and be reliably and stably kept in the lifted state, avoiding the phenomenon that the robotic arm compresses and falls back due to the increase of the working load. It can be understood that, since the nut 121 and the lead screw 122 adopt a non-self-locking thread connection, the driving part 123 provides a smaller torque, and through the transmission and conversion of the nut 121 and the lead screw 122 into a supporting force, a larger working load can be supported, which is beneficial to reducing the energy consumption of the driving part 123.

[0047] When the robotic joint 100 is accidentally powered off when lifted to the unfolded state, since the nut 121 and the lead screw 122 adopt a non-self-locking thread connection, the robotic joint 100 can be returned to the folded state by an external force (such as the working load or the user's hand pressing), so that the robotic arm 200 is returned to the folded storage position, reducing the space occupied by the robotic arm 200 and improving the user's satisfaction.

[0048] Among them, the driving part 123 can be a motor, and the output shaft of the motor is connected to the first end of the lead screw 122. For example, the output shaft of the driving part 123 and the lead screw 122 can be connected by an adhesive, a key, or other means. It can be understood that the output shaft of the driving part 123 and the lead screw 122 can also be connected through a transmission mechanism. For example, the transmission mechanism can be a gear mechanism, a belt mechanism, a chain drive mechanism, etc.

[0049] Furthermore, by connecting the driving part 123 to the lead screw 122 to drive the relative movement of the lead screw 122 and the nut 121, compared with the related art where the driving part is connected to the nut to drive the relative movement of the lead screw and the nut, the driving force is smaller. In this way, in the case of an accidental power failure of the driving part 123, with a smaller external force, the connecting frame 110 in the lifted and unfolded state can be lowered to the folded state, that is, the user can overcome a smaller pressure to press down the robotic joint 100 to the lowered and folded state, which is convenient for the folding and storage of the robotic arm 200, convenient for user operation, and improves user satisfaction.

[0050] Furthermore, the connecting frame 110 is hinged to the base 211, and the nut 121 is hinged to the base 211, so that during the process of the driving part 123 driving the relative movement of the lead screw 122 and the nut 121 to drive the connecting frame 110 to lift or lower relative to the base 211, the nut 121 will not interfere with the base 211, that is, the nut 121 can rotate relative to the base 211 to ensure the movement of the lead screw 122 and the nut 121 within a certain range and adapt to the rotation range of the connecting frame 110 relative to the base 211.

[0051] As Figure 13 shown, in some possible implementation embodiments provided by the present utility model, the lead screw 122 is provided with an external thread structure 1221. Thus, the second end of the lead screw 122 passes through the nut 121, so that the external thread structure 1221 of the lead screw 122 cooperates with the nut 121 to realize the connection between the lead screw 122 and the nut 121. By making the thread lead angle of the external thread structure 1221 on the lead screw 122 greater than the equivalent friction angle of the thread pair composed of the lead screw 122 and the nut 121, the lead screw 122 and the nut 121 can achieve a non-self-locking thread connection. In this way, after the driving part 123 is powered off, with an external force, the lead screw 122 and the nut 121 can move relative to each other, so that the robotic joint 100 in the lifted and unfolded state returns to the lowered and folded state, and the robotic arm 200 at the working position returns to the storage position, reducing the space occupied by the robotic arm 200 and improving user satisfaction.

[0052] In some possible implementation embodiments provided by the present utility model, the lead screw 122 is a steel part, a copper part, or a copper alloy part, and the nut 121 is a steel part, a copper part, or a copper alloy part.

[0053] Among them, the steel part has high strength and hardness, is not easy to rust, has a long service life, and has a low cost, which is suitable for popularization and application.

[0054] Among them, the copper part has good corrosion resistance, can meet the working environment with low cleanliness and humidity of the cleaning device 300, and has a low failure rate.

[0055] Among them, the copper alloy parts have high strength, high corrosion resistance, excellent wear resistance, long service life, and are suitable for popularization and application.

[0056] In some possible embodiments provided by the present utility model, the pitch diameter of the external thread structure 1221 is 3 mm to 6 mm, and the lead of the external thread structure 1221 is 2.5 mm to 5.5 mm.

[0057] Among them, the thread lead angle formula of the external thread structure 1221 of the lead screw 122 is: ψ = arctan(nP / πd2), where n is the number of threads of the external thread structure 1221, P is the pitch, and d2 is the pitch diameter of the external thread structure.

[0058] Among them, the formula for the equivalent friction angle of the thread pair composed of the lead screw 122 and the nut 121 is: ρ = arctan(1.15μ), where μ is the friction coefficient of the thread pair.

[0059] Thus, by setting the pitch diameter of the external thread structure 1221 to 3 mm to 6 mm and the lead of the external thread structure 1221 to 2.5 mm to 5.5 mm, it can be ensured that the thread lead angle of the external thread structure 1221 is greater than the equivalent friction angle of the thread pair composed of the lead screw 122 and the nut 121, so as to ensure that the nut 121 and the lead screw 122 adopt a non-self-locking thread connection.

[0060] Specifically, the pitch diameter of the external thread structure 1221 can be 3 mm, 4 mm, 5 mm, 6 mm, or other sizes; the lead of the external thread structure 1221 can be 2.5 mm, 3.5 mm, 4.5 mm, 5.5 mm, or other sizes.

[0061] Specifically, taking the friction coefficient μ of the thread pair composed of the lead screw nut 121 as 0.25, the external thread structure 1221 of the lead screw 122 as TR4, the thread pitch diameter d is about 3.5 mm, and the thread lead is 4 mm as an example, according to the thread lead angle formula and the formula for the equivalent friction angle of the thread pair, it is calculated that the thread lead angle ψ of the external thread structure 1221 of the lead screw 122 is 0.35 rad, and the equivalent friction angle ρ of the thread pair composed of the lead screw 122 and the nut 121 is 0.28 rad. Thus, it can be seen that the thread lead angle of the external thread structure 1221 of the lead screw 122 is greater than the equivalent friction angle of the thread pair composed of the lead screw 122 and the nut 121.

[0062] Such as Figure 4 、 Figure 5 、 Figure 9 and Figure 10As shown, in some possible embodiments provided by the present utility model, the lifting assembly 120 further includes: a motor bracket 124, the motor bracket 124 is hinged to the connecting frame 110, the driving part 123 is installed on the motor bracket 124, and the lead screw 122 passes through the motor bracket 124 and is connected to the driving part 123.

[0063] In this embodiment, the motor bracket 124 is hinged to the connecting frame 110, that is, the motor bracket 124 is rotatable relative to the connecting frame 110. The driving part 123 is installed on the motor frame, and the lead screw 122 passes through the motor bracket 124 and is connected to the driving part 123. With such a setting, during the process of the connecting frame 110 lifting or lowering relative to the base 211, the driving part 123 connected to the lead screw 122 will not interfere with the connecting frame 110. Furthermore, it can ensure that the lead screw 122 moves smoothly relative to the nut 121 without getting stuck, thereby improving the reliability and smoothness of the lifting and lowering of the mechanical joint 100.

[0064] That is to say, for the mechanical joint 100 provided by the embodiment of the present utility model, by hinging the connecting frame 110 to the base 211, the nut 121 to the base 211, and the motor bracket 124 to the connecting frame 110, an active triangular structure is formed. By connecting the lead screw 122 to the driving part 123 and passing through the nut 121, when the driving part 123 drives the lead screw 122 to rotate, the lead screw 122 can move relative to the nut 121 to achieve the lifting or lowering of the connecting frame 110 relative to the base 211, and the structure is simple.

[0065] Specifically, as Figure 5 、 Figure 10As shown, the rotation center of the connecting frame 110 relative to the base 211 is set on the base 211. For example, the hinge point between the connecting frame 110 and the base 211 is point O, and the rotation center of the nut 121 relative to the base 211 is set on the base 211. For example, the hinge point between the nut 121 and the base 211 is N. Thus, the distance ON between O and N remains unchanged. Similarly, the rotation center of the motor bracket 124 relative to the connecting frame 110 is set on the connecting frame 110. For example, the hinge point between the motor bracket 124 and the connecting frame 110 is M. Thus, the distance OM between O and M remains unchanged. When the position of the base 211 remains stationary, only by adjusting the distance between M and N can the lifting and lowering of the connecting frame 110 be achieved. Since the lead screw 122 and the nut 121 are meshed and connected through a threaded structure, when the driving part 123 drives the lead screw 122 to rotate, the nut 121 will move away from or approach the driving part 123, that is, change the distance MN between the rotation center N of the nut 121 relative to the base 211 and the rotation center M of the motor bracket 124 relative to the connecting frame 110. Thus, by driving the relative movement of the lead screw 122 and the nut 121 by the driving part 123, the lifting and lowering of the mechanical joint 100 can be achieved, with a simple structure and convenient operation.

[0066] As Figure 3 、 Figure 5 、 Figure 10 、 Figure 13 As shown, in some possible implementation embodiments provided by the present invention, the lifting assembly 120 further includes: a rotating member 125, the rotating member 125 is sleeved outside the lead screw 122, the lead screw 122 is provided with a stepped structure, and the rotating member 125 is located between the stepped structure and the motor bracket 124 to rotatably connect the lead screw 122 and the motor bracket 124; such a setting enables the axial thrust of the lead screw 122 to be supported by the motor bracket 124, which can reduce the friction of the lead screw 122 during movement, and thus is beneficial to improving the service life of the lead screw 122 and the reliability of the mechanical joint 100.

[0067] Among them, the rotating member 125 includes a bearing or a sleeve to reduce the friction of the lead screw 122 during movement by using the bearing or the sleeve.

[0068] In a specific embodiment, since the mechanical joint uses a thread pair composed of a lead screw and a nut for the lifting or lowering movement of the mechanical joint, therefore, the required torque of the driving motor can be calculated with reference to the following formula:

[0069] ψ = arctan(nP / πd2); p = arctan(1.15u);

[0070] Wherein, F is the circumferential load on the screw pair; d2 is the pitch diameter of the external thread structure; ψ is the lead angle of the thread; n is the number of threads in the external thread structure; P is the pitch; ρ is the equivalent friction angle; μ is the friction coefficient of the screw pair. Among them, the situations of "+" and "-" in the formula depend on the direction of the frictional force in different motion conditions.

[0071] In a specific embodiment, taking the external thread structure specification of the lead screw as TR4, the pitch diameter d of the thread is approximately 3.5 mm, the friction coefficient μ between the lead screw and the nut is approximately 0.25, and the lead of the thread is 4 mm. Then, the lead angle ψ of the thread can be calculated as 0.35 rad, and the equivalent friction angle ρ of the screw pair composed of the lead screw 122 and the nut 121 is 0.28 rad. Among them, the thrust F2 generated by the driving part 123 driving the lead screw 122 to move is along the NM direction, and its lever arm R2 with respect to the rotation center of the connecting frame 110 of the mechanical joint 100 relative to the base 211 is approximately 7 mm.

[0072] Suppose that when the robotic arm 200 exits the bin and returns to the bin, the load on the mechanical joint 100 mentioned above is T1_1 = 0.5 Nm, and the maximum load in the working state after lifting is T1_2 = 3 Nm. Then, the force conditions in these three working conditions will be discussed separately below.

[0073] I. Exiting the bin

[0074] When the robotic arm 200 exits the bin, for the mechanical joint 100, it needs to perform a lifting motion. At this time, the lead screw 122 is driven to rotate by the driving part 123, and the nut 121 moves along the lift direction of the lead screw 122, as Figure 10 shown, the nut moves in the direction indicated by Y+.

[0075] For the lead screw 122, it moves relative to the nut 121 in the opposite direction of the lift, that is, the lead screw 122 moves relative to the nut 121 in the Y- direction, and its force diagram is as Figure 11 shown.

[0076] Wherein, Fa is the axial supporting force of the lead screw 122 received by the rotating part 125; Fm is the circumferential driving force of the driving part 123; Fn is the reverse supporting force of the nut 121 on the lead screw 122, Ff is the frictional force of the nut 121 on the lead screw 122, the resultant force of Fn and Ff is the total reaction force Fr of the nut 121, the included angle between Fr and Fn is the equivalent friction angle ρ of the screw pair, ψ is the lead angle of the external thread structure of the lead screw 122. Among them, the direction of Fa is parallel or coincident with the axial direction of the lead screw 122 when the robotic arm 200 is in the lowered and folded state.

[0077] Then, from the force balance triangle, it can be known that: Fm = Fa × arctan(ψ + ρ); the torque that the motor needs to provide (motor rotates forward) is: Nm = Fm × d / 2 = Fa × arctan(ψ + ρ) × d / 2;

[0078] Based on the foregoing parameters, it is obtained that: Fa = 71.4 N; Fm = 51.95 N; Nm = 0.09 Nm.

[0079] II. Return to the warehouse

[0080] When the robotic arm 200 returns to the warehouse, for the robotic joint 100, it needs to perform a descending and retracting movement. At this time, the lead screw 122 is driven by the driving part 123 to rotate, and the nut 121 moves along the reverse lift direction of the lead screw 122. As Figure 5 shown, the nut 121 moves along the lead screw in the Y- direction.

[0081] For the lead screw 122, it moves along the lift direction relative to the nut 121. As Figure 5 shown, the lead screw 122 moves in the Y+ direction relative to the nut 121, and its force diagram is as Figure 6 shown.

[0082] Among them, Fa is the axial support force of the lead screw 122 received by the rotating part 125; Fm is the circumferential driving force of the driving part 123; Fn is the reverse support force of the nut 121 on the lead screw 122, Ff is the friction force of the nut 121 on the lead screw 122, and the resultant force of Fn and Ff is the total reaction force Fr of the nut 121. The angle between Fr and Fn is the equivalent friction angle ρ of the thread pair, and ψ is the thread lift angle of the external thread structure of the lead screw 122. Among them, the direction of Fa is parallel or coincident with the axial direction of the lead screw 122 when the robotic arm 200 is in the lifted state.

[0083] Then, from the force balance triangle, it can be known that Fm = -Fa × arctan(ψ - ρ),

[0084] The torque that the driving part 123 needs to provide (motor reverse rotation) is: Nm = Fm × d / 2 = -Fa × arctan(ψ - ρ) × d / 2;

[0085] Since this scheme uses a non-self-locking lead screw 122 nut, that is, ψ - ρ > 0, so Fm should be a negative value. That is, when not considering factors such as mechanism eccentric load, friction, and motor gearbox rotation resistance, when the motor drives the robotic joint 100 to return to the warehouse, basically no driving torque needs to be provided. Among them, Figure 6 the direction indicated by the arrow of Fm is the motor rotation direction.

[0086] Based on the foregoing parameters, it is obtained that: Fa = 71.4 N; Fm = -4.9335 N; Nm = -0.0086 Nm.

[0087] III. Maintain at the working position

[0088] When the robotic arm 200 is maintained in the working state, in order to resist the working load and maintain the position of the mechanical joint 100, the driving part 123 needs to make the nut 121 tend to move in the lifting direction of the lead screw 122, as Figure 5 shown, that is, the nut 121 has a tendency to move in the Y+ direction along the lead screw 122. For the lead screw 122, its force diagram is as Figure 7 shown.

[0089] Among them, Fa is the axial support force of the lead screw 122 by the rotating part 125; Fm is the circumferential driving force of the driving part 123; Fn is the reverse support force of the nut 121 on the lead screw 122, and Ff is the friction force of the nut 121 on the lead screw 122. The resultant force of Fn and Ff is the total reaction force Fr of the nut 121. The angle between Fr and Fn is the equivalent friction angle ρ of the thread pair, and ψ is the thread lead angle of the external thread structure of the lead screw 122. Among them, the direction of Fa is parallel or coincident with the axial direction of the lead screw 122 when the robotic arm 200 is in the lifted state.

[0090] Then, from the force balance triangle, it can be known that Fm = Fa × arctan(ψ - ρ), and the torque that the motor needs to provide (motor rotates forward) is: Nm = Fm × d / 2 = Fa × arctan(ψ - ρ) × d / 2

[0091] Based on the foregoing parameters, it is obtained that: Fa = 428.57N; Fm = 29.6N; Nm = 0.0518 Nm.

[0092] From the above data, it can be seen that at this time, only a small holding torque needs to be given to the motor to keep the motor in the working position. When the mechanical joint 100 needs to be pushed down by an external force to lower the robotic arm 200 into the bin, the motor is powered off, and the mechanical joint 100 can be unlocked. At this time, the mechanical joint 100 can be pushed by a small external force to make the mechanical joint 100 descend, which is convenient for the user to operate. In this way, after the mechanical joint 100 is in the lifted and deployed state and the driving part 123 is accidentally powered off, the user can push the mechanical joint 100 to descend with a small force to lower the robotic arm 200 into the bin, with simple operation and convenient use.

[0093] As Figure 5 、 Figure 10 、 Figure 12As shown, in some possible embodiments provided by the present utility model, first cylindrical bosses 1211 are provided on opposite sides of the outer wall of the nut 121, and first receiving grooves 2111 are formed on the base 211. The first cylindrical bosses 1211 are received in the first receiving grooves 2111 and can rotate within the first receiving grooves 2111. Thus, the nut 121 is hinged to the base 211 through the first cylindrical bosses 1211 on both sides, with a simple structure, easy to process, low cost, and suitable for popularization and application. Moreover, such a setting enables the rotation range of the nut 121 relative to the base 211 to reach 360°, thereby meeting the requirement of a relatively large lifting range of the connecting frame 110 relative to the base 211 and expanding the usage range of the product.

[0094] Specifically, the first cylindrical bosses 1211 and the nut 121 can be of an integrally formed structure or a split structure. Among them, when the first cylindrical bosses 1211 and the nut 121 are of an integrally formed structure, it is convenient for processing, simplifies the operation of connecting the first cylindrical bosses 1211 and the nut 121, and is suitable for mass production. When the first cylindrical bosses 1211 and the nut 121 are of a split structure, the first cylindrical bosses 1211 and the nut 121 can be disassembled and separated for repair or replacement, saving the cost of maintenance and replacement parts. It can be understood that the first cylindrical bosses 1211 and the nut 121 can be connected by means of bolt structures, snap-fit structures, tenon and mortise structures, adhesives, welding, etc.

[0095] As Figure 5 、 Figure 10 shown, in some possible embodiments provided by the present utility model, second cylindrical bosses 1241 are provided on opposite sides of the motor bracket 124, and second receiving grooves are formed on the connecting frame 110. The second cylindrical bosses 1241 are received in the second receiving grooves and can rotate within the second receiving grooves.

[0096] Thus, through the second cylindrical bosses 1241 and the second receiving grooves, the hinging of the motor bracket 124 and the connecting frame 110 can be achieved, with a simple structure, easy to process, low cost, and suitable for popularization and application. Such a setting enables the rotation range of the motor bracket 124 relative to the connecting frame 110 to reach 360°, thereby meeting the requirement of a relatively large lifting angle of the connecting frame 110 relative to the base 211.

[0097] Among them, the axis of the second cylindrical bosses 1241 is parallel to the axis of the first cylindrical bosses 1211, which can ensure that during the relative movement of the lead screw 122 and the nut 121, the nut 121 and the base 211 will not get stuck, and the motor bracket 124 and the connecting frame 110 will not get stuck, so as to ensure the smoothness of the lifting and lowering of the connecting frame 110 and improve the smoothness of the lifting and lowering of the mechanical joint 100.

[0098] Specifically, the second cylindrical boss 1241 and the motor bracket 124 can be of an integrally formed structure or a split structure. Among them, the second cylindrical boss 1241 and the motor bracket 124 being of an integrally formed structure is convenient for processing, simplifies the operation of connecting the second cylindrical boss 1241 and the motor bracket 124, and is suitable for mass production. The second cylindrical boss 1241 and the motor bracket 124 being of a split structure enables the second cylindrical boss 1241 and the motor bracket 124 to be disassembled and separated for repair or replacement, saving the cost of maintenance and replacement parts. It can be understood that the second cylindrical boss 1241 and the motor bracket 124 can be connected by means of a bolt structure, a snap connection structure, a mortise and tenon structure, an adhesive, welding, etc.

[0099] As Figure 3 , Figure 5 , Figure 10 shown, in some possible implementation embodiments provided by the present utility model, the mechanical joint 100 further includes: a connecting shaft 130, the axis of the connecting shaft 130 is arranged parallel to the axis of the first cylindrical boss 1211 and is connected to the base 211; the end of the connecting frame 110 close to the base 211 is sleeved outside the connecting shaft 130 and is rotatably connected to the connecting shaft 130. Thus, by the end of the connecting frame 110 close to the base 211 being rotatably connected relative to the connecting shaft 130, the hinged connection between the connecting frame 110 and the base 211 can be achieved, with a simple structure and easy implementation.

[0100] Among them, the axis of the connecting shaft 130 is arranged parallel to the axis of the first cylindrical boss 1211, which can ensure that during the relative movement of the lead screw 122 and the nut 121, the nut 121 and the base 211 will not get stuck, and the connecting frame 110 and the base 211 will not get stuck, so as to ensure the smoothness of the lifting and lowering of the connecting frame 110 and improve the smoothness of the lifting and lowering of the mechanical joint 100.

[0101] Among them, the connecting shaft 130 can be relatively fixedly connected to the base 211, that is, the connecting shaft 130 does not rotate relative to the base 211. Specifically, the connecting shaft 130 can be connected to the base 211 through a snap connection structure, a plug connection structure, a mortise and tenon structure, a key, etc.

[0102] Further, as Figure 12 shown, the base 211 is provided with a mounting hole 2112 for mounting the connecting shaft 130, and the mounting hole 2112 and the first receiving groove 2111 are located on the same side wall of the base 211. For example, the first receiving groove 2111 and the mounting hole 2112 are simultaneously provided on two opposite side walls of the base 211, and the axis of the first receiving groove 2111 and the axis of the mounting hole 2112 are arranged in parallel.

[0103] As Figure 5 and Figure 10As shown, in some possible embodiments provided by the present utility model, a connection ring 111 is provided at the end of the connecting frame 110 close to the base 211. The connection ring 111 is sleeved outside the connecting shaft 130. The mechanical joint 100 further includes a connecting bearing 140 connected between the connection ring 111 and the connecting shaft 130. Thus, the connecting shaft 130 and the connection ring 111 can be rotatably connected through the connecting bearing 140, and further the connecting frame 110 and the connecting shaft 130 can be rotatably connected to realize the hinge connection between the connecting frame 110 and the base 211, with a simple structure.

[0104] Wherein, the number of the connection rings 111 is two. By rotatably connecting the two connection rings 111 with the connecting shaft 130, the reliability and stability of the rotation of the connecting frame 110 relative to the base 211 can be improved, and further the reliability and stability of the lifting and lowering of the mechanical joint 100 can be improved.

[0105] Such as Figure 1 、 Figure 2 、 Figure 8 and Figure 9 As shown, an embodiment of the second aspect of the present utility model provides a robotic arm 200, including: the mechanical joint 100 of any one of the first aspect. Since the robotic arm 200 includes the mechanical joint 100 of any one of the foregoing embodiments, it has all the beneficial technical effects of the foregoing mechanical joint 100, which will not be elaborated herein one by one.

[0106] Specifically, the robotic arm 200 further includes a fixed seat 220. By connecting the fixed seat 220 with the machine body 310, the installation of the robotic arm 200 and the machine body 310 can be realized. The end of the robotic arm 200 further includes a mechanical hand 250. Through the mechanical hand 250, operations of grasping and releasing objects can be realized to grasp or move obstacles, objects, and garbage near the cleaning device 300.

[0107] Furthermore, in order to improve the flexibility of the movement of the robotic arm 200, the robotic arm 200 may further include other joints, such as Figure 1 and Figure 2As shown in the figure, the robotic arm 200 may further include a slewing joint 210, a first tipping joint 230, and a second tipping joint 240. Among them, the slewing joint 210 is connected to the fixed base 220, and the slewing joint 210 is rotatable relative to the fixed base 220. The robotic joint 100 is connected to the slewing joint 210. Specifically, the base 211 may be a part of the slewing joint 210, and the robotic joint 100 can be lifted or lowered relative to the slewing joint 210. The first tipping joint 230 is connected to the robotic joint 100. The first tipping joint 230 and the slewing joint 210 are located at both ends of the robotic joint 100. The first tipping joint 230 can be lifted or lowered relative to the robotic joint 100. The second tipping joint 240 and the robotic joint 100 are located at both ends of the first tipping joint 230. The second tipping joint 240 can be lifted or lowered relative to the first tipping joint 230. The robotic hand 250 and the first tipping joint 230 are connected to both ends of the second tipping joint 240.

[0108] That is to say, for the robotic arm 200 provided in the embodiment of the present invention, the fixed base 220 and the robotic hand 250 are respectively at both ends thereof, and a slewing joint 210, a robotic joint 100, a first tipping joint 230, and a second tipping joint 240 are sequentially connected in the direction from the fixed base 220 to the robotic hand 250. Thus, the movement range of the robotic arm 200 can be increased, and further the cleaning range of the cleaning device 300 can be improved, and the usage range of the product can be expanded.

[0109] As Figure 14 As shown in the figure, an embodiment of the third aspect of the present invention provides a cleaning device 300, including: the robotic arm 200 provided in any of the foregoing embodiments. Since the cleaning device 300 includes the robotic arm 200 in any of the foregoing embodiments, it has all the technical effects of the foregoing robotic arm 200, which will not be elaborated herein one by one.

[0110] Among them, the cleaning device 300 includes a main body 310, and the robotic arm 200 is connected to the main body 310, so that the robotic arm can move along with the movement of the main body 310, and further can move to the position of the to-be-worked station along with the movement of the main body 310 to realize the grasping and moving of an object.

[0111] Further, the main body 310 is provided with a receiving cavity, and the fixing seat 220 of the robotic arm 200 is connected in the receiving cavity. The robotic arm 200 can be retracted into the receiving cavity or extended to the outside of the receiving cavity. Thus, according to the object-grabbing requirement, the robotic arm 200 can be extended to the outside of the receiving cavity or retracted into the receiving cavity. Since the receiving cavity is provided on the device body, the structure of the main body 310 can be fully utilized to achieve the retraction of the robotic arm 200, with a simple structure, which can meet the design requirements of the cleaning device 300 for being structurally compact and having a small volume. At the same time, when the object does not need to be grabbed, retracting the robotic arm 200 into the receiving cavity can reduce the damage of the robotic arm 200 caused by an external object colliding with the robotic arm 200, thereby improving the service life of the robotic arm 200.

[0112] The present disclosure has been illustrated by the above embodiments, but it should be understood that the above embodiments are only for the purpose of exemplification and illustration, and are not intended to limit the present disclosure within the scope of the described embodiments. In addition, those skilled in the art can understand that the present disclosure is not limited to the above embodiments, and more variations and modifications can be made according to the teachings of the present disclosure, and these variations and modifications all fall within the scope claimed by the present disclosure. The protection scope of the present disclosure is defined by the appended claims and their equivalent scope.

Claims

1. A mechanical joint (100) for a robotic arm (200), characterized in that, The mechanical joint (100) includes: A connecting frame (110) and a lifting assembly (120). The connecting frame (110) is hinged to the base (211) of the robotic arm (200). The lifting assembly (120) includes a nut (121), a lead screw (122), and a driving portion (123). The nut (121) is connected to the lead screw (122) by a non-self-locking thread and is hinged to the base (211). The driving portion (123) is disposed on the connecting frame (110). The first end of the lead screw (122) is connected to the driving portion (123), and the second end of the lead screw (122) passes through the nut (121). Wherein, the driving portion (123) is used to drive the lead screw (122) to rotate, so that the lead screw (122) and the nut (121) move relative to each other to drive the connecting frame (110) to lift or lower relative to the base (211).

2. The mechanical joint (100) according to claim 1, wherein The lead screw (122) is provided with an external thread structure (1221), and the lead angle of the external thread structure (1221) is greater than the equivalent friction angle of the thread pair composed of the lead screw (122) and the nut (121).

3. The mechanical joint (100) according to claim 2, wherein The lead screw (122) is made of steel, copper, or copper alloy; The nut (121) is made of steel, copper, or copper alloy.

4. The mechanical joint (100) according to claim 3, wherein The pitch diameter of the external thread structure (1221) is 3 mm to 6 mm, and the lead of the external thread structure (1221) is 2.5 mm to 5.5 mm.

5. The mechanical joint (100) according to claim 1, characterized in that, The lifting assembly (120) further includes: A motor bracket (124). The motor bracket (124) is hinged to the connecting frame (110). The driving portion (123) is installed on the motor bracket (124), and the lead screw (122) passes through the motor bracket (124) and is connected to the driving portion (123).

6. The mechanical joint (100) according to claim 5, characterized in that, The lifting assembly (120) further includes: A rotating member (125). The rotating member (125) is sleeved outside the lead screw (122). The lead screw (122) is provided with a stepped structure, and the rotating member (125) is located between the stepped structure and the motor bracket (124) to rotatably connect the lead screw (122) and the motor bracket (124).

7. The mechanical joint (100) according to claim 5, wherein On opposite sides of the outer wall of the nut (121), there are first cylindrical bosses (1211). A first receiving groove (2111) is formed on the base (211). The first cylindrical bosses (1211) are received in the first receiving groove (2111) and can rotate in the first receiving groove (2111).

8. The mechanical joint (100) according to claim 7, wherein On opposite sides of the motor bracket (124), there are second cylindrical bosses (1241). A second receiving groove is formed on the connecting frame (110). The second cylindrical bosses (1241) are received in the second receiving groove and can rotate within the second receiving groove.

9. The mechanical joint (100) according to claim 7, characterized in that, Further comprising: A connecting shaft (130), the axis of the connecting shaft (130) is arranged parallel to the axis of the first cylindrical boss (1211) and is connected to the base (211); The end of the connecting frame (110) close to the base (211) is sleeved outside the connecting shaft (130) and is rotatably connected to the connecting shaft (130).

10. The mechanical joint (100) according to claim 9, wherein The end of the connecting frame (110) close to the base (211) is provided with a connecting ring (111), and the connecting ring (111) is sleeved outside the connecting shaft (130); The mechanical joint (100) further comprises a connecting bearing (140) connected between the connecting ring (111) and the connecting shaft (130).

11. A robotic arm (200), characterized in that, Comprising: The mechanical joint (100) according to any one of claims 1 to 10.

12. A cleaning device (300), characterized in that, Comprising: The robotic arm (200) according to claim 11.

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