An electric push rod for a humanoid robot

Abstract

The utility model discloses an electric push rod for humanoid robot, including drive motor, gear box, stroke slide rail, nut, mounting panel, stroke axle and screw rod, stroke axle is located between screw rod and stroke slide rail and is fixed with nut, the nut is contacted through non -circular surface with stroke slide rail, the mounting panel is cooperated with the outer periphery of stroke axle. The outer periphery of stroke slide rail and stroke axle are all cylindrical surface with cutting plane, and the cutting plane of stroke slide rail is equipped with the reading head pcb, and the cutting plane of stroke axle is equipped with the inductive magnetic grid, and stroke slide rail has the gap for the detection head of reading head pcb to extend, so that the detection head of reading head pcb and inductive magnetic grid are opposite and induct. The utility model discloses the design of cutting plane sets up the inductive part in stroke slide rail, will not occupy additional space, and at the same time, the inductive magnetic grid is arranged on stroke axle, and the cooperation of nut and stroke slide rail guarantees the operation straightness, to realize the accurate movement under the micro size.

Description

Technical Field

[0001] This utility model relates to the field of electric linear actuator technology, and in particular to an electric linear actuator for humanoid robots. Background Technology

[0002] In recent years, the humanoid robot industry has developed rapidly, and its technology has become increasingly mature. With this industry growth, the demand for supporting drive components is also constantly increasing. Because robot dexterities have high requirements for the installation dimensions of electric actuators, conventional robot dexterities use electric actuators to mount the linear detection unit outside the travel rail. For cylindrical travel rails, this not only makes the installation of the linear detection unit more difficult but also increases the radial dimension of the actuator section.

[0003] Most push rods on the market are currently circular or square in structure, consistent with the motor. The sensing unit is usually placed at the tail of the motor or on the square cavity. The tail needs to go through a series of conversion calculations to obtain the linear motion data. The linear sensing unit is usually large, and the same applies to the square structure, generally 28~42mm in size, making it difficult to apply in the humanoid robot industry. Existing technology also has a solution of installing the sensing unit inside the slide rail, such as the push rod disclosed in patent number CN202321786155. A circuit board is set inside the outer tube, and a sensing plate is set on the nut. The circuit board realizes the start or stop of the push rod through the contact of different circuits with the sensing plate. Therefore, the circuit board needs to be laid along the travel path of the sensing plate, and the circuit structure of the circuit board is relatively complex. In addition, since the nut and the outer tube need to cooperate with the wall to ensure linear motion, the sensing plate can only be recessed inside the nut, thereby reducing the contact area between the nut and the outer tube, which can easily lead to a decrease in linear motion accuracy.

[0004] Therefore, it is necessary to design an electric actuator with a simple and compact structure that can accurately calculate linear motion data. Utility Model Content

[0005] To address the technical problems of complex sensor unit design and large space occupation in existing electric linear actuators, this invention provides an electric linear actuator for humanoid robots to solve the above problems.

[0006] The technical solution adopted by this utility model to solve its technical problem is: an electric push rod for a humanoid robot, including a drive motor, a gearbox, a travel slide rail, a nut, a mounting plate, a travel shaft, and a lead screw. The drive motor, gearbox, travel slide rail, and mounting plate are fixed in sequence. The lead screw is connected to the motor shaft of the drive motor through the gearbox. The nut is threadedly connected to the lead screw. The travel shaft is located between the lead screw and the travel slide rail and is fixed to the nut. The nut is located inside the travel slide rail and contacts the travel slide rail through a non-circular surface. The mounting plate mates with the outer circumferential surface of the travel shaft.

[0007] The outer peripheral surfaces of the travel slide rail and the travel shaft are both cylindrical surfaces with cutting planes. A reading head PCB is mounted on the cutting plane of the travel slide rail, and an induction magnetic grid extending along the running direction of the travel shaft is mounted on the cutting plane of the travel shaft. The travel slide rail has a notch for the probe of the reading head PCB to extend into, so that the probe of the reading head PCB is directly facing the induction magnetic grid for sensing.

[0008] In an optional embodiment of this utility model, the notch is located at one end of the travel slide rail connecting mounting plate.

[0009] In an optional embodiment of this utility model, the mounting plate includes a mounting part and an injection-molded body fixed to the inner surface of the mounting part, wherein the inner surface of the injection-molded body cooperates with the travel shaft and the induction magnetic grid.

[0010] In an optional embodiment of this utility model, the outer peripheral surface of the injection molded body has annular ribs and several axial ribs, and the inner surface of the mounting part has a groove for accommodating the annular ribs and axial ribs.

[0011] In an optional embodiment of this utility model, the cross-section of the outer circumferential surface of the nut includes symmetrically arranged first arc segments and a planar segment connecting the two first arc segments, wherein the diameter of the first arc segment is greater than the outer diameter of the travel shaft.

[0012] In an optional embodiment of this utility model, the inductive magnetic grating is arranged parallel to the planar segment, and the planar segment also has a protruding second arc segment, the highest point of which is higher than the inductive magnetic grating.

[0013] In an optional embodiment of this utility model, the cross-section of the inner surface of the travel slide rail is partially or entirely the same as the outer cross-section of the nut.

[0014] In an optional embodiment of this utility model, the nut includes a sliding fit part and a threaded connection part. The threaded connection part is fixed to the stroke shaft, and the inner circumferential surface of the sliding fit part is connected to the lead screw, while the outer circumferential surface contacts the stroke slide rail.

[0015] In an optional embodiment of this utility model, the distance from the planar segment to the center of the nut is equal to the outer diameter of the travel shaft.

[0016] In an optional embodiment of this utility model, the outer diameter of the travel shaft is 8~10mm, and the width of the induction magnetic grating is 3~5mm.

[0017] The beneficial effects of this utility model are: (1) According to the size requirements of humanoid robots, this utility model uses the design of the cutting plane to set the sensing component in the travel slide rail, which will not occupy extra space. At the same time, the sensing magnetic grid is arranged on the travel shaft, and the straightness of the operation is guaranteed by the cooperation of the nut and the travel slide rail, thereby realizing precise movement under small size.

[0018] (2) The present invention reduces the internal space of the travel slide rail by designing the outer periphery of the nut, making the structure more compact.

[0019] (3) The present invention uses the design of the injection molded body on the mounting plate to make the mounting plate fit with the outer surface of the stroke shaft and the induction magnetic grid, so as to avoid the end of the stroke shaft shaking. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0021] Figure 1 This is a front view of a specific embodiment of the electric push rod for humanoid robots described in this utility model; Figure 2 This is an axial sectional view of a specific embodiment of the electric push rod for humanoid robots described in this utility model; Figure 3 This is an exploded view of a specific embodiment of the electric push rod for a humanoid robot according to this utility model; Figure 4 This is a schematic diagram of the end face of the mating part between the mid-stroke slide rail and the nut in this utility model; Figure 5 This is a schematic diagram of the connection between the stroke shaft and the nut in this utility model; Figure 6 This is a schematic diagram showing the connection relationship between the mid-stroke slide rail, the reader PCB, and the mounting plate of this utility model; Figure 7 This is an exploded view of the mounting plate in this utility model.

[0022] In the diagram, 1. Drive motor, 2. Gearbox, 3. Travel slide rail, 301. Notch, 4. Nut, 401. Sliding fit, 402. Threaded connection, 5. Mounting plate, 501. Mounting part, 502. Injection molded body, 6. Travel shaft, 7. Lead screw, 8. Cutting plane, 9. Reader PCB, 10. Induction magnetic grid, 11. Adapter plate, 12. Bearing, 13. First arc segment, 14. Planar segment, 15. Annular rib, 16. Axial rib, 17. Groove, 18. Second arc segment. Detailed Implementation

[0023] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0024] An electric actuator for a humanoid robot includes a drive motor 1, a gearbox 2, a travel slide rail 3, a nut 4, a mounting plate 5, a travel shaft 6, and a lead screw 7. The drive motor 1, gearbox 2, travel slide rail 3, and mounting plate 5 are fixed in sequence. The lead screw 7 is connected to the motor shaft of the drive motor 1 through the gearbox 2. The nut 4 is threadedly connected to the lead screw 7. The travel shaft 6 is located between the lead screw 7 and the travel slide rail 3 and is fixed to the nut 4. The nut 4 is located inside the travel slide rail 3 and contacts the travel slide rail 3 through a non-circular surface. The mounting plate 5 mates with the outer circumferential surface of the travel shaft 6.

[0025] The drive motor 1 is used to drive the lead screw 7 to rotate. The nut 4 moves along the spiral of the lead screw 7. Under the restriction of the travel slide rail 3, the nut 4 can only move in a reciprocating linear motion, thereby driving the travel shaft 6 fixed thereto to move in a reciprocating linear motion. The end face size of the travel shaft 6 is smaller than the end face size of the nut 4. Therefore, the travel slide rail 3 has a small guiding effect on the travel shaft 6. It is necessary to rely on the mounting plate 5 to guide the travel shaft 6 to avoid the end of the travel shaft 6 from shaking and affecting the output straightness.

[0026] The outer peripheral surfaces of the travel slide rail 3 and the travel shaft 6 are both cylindrical surfaces with cutting planes 8. A reading head PCB 9 is mounted on the cutting plane 8 of the travel slide rail 3, and an induction magnetic grid 10 extending along the running direction of the travel shaft 6 is mounted on the cutting plane 8 of the travel shaft 6. The travel slide rail 3 has a notch 301 for the probe of the reading head PCB 9 to extend into, so that the probe of the reading head PCB 9 is directly facing the induction magnetic grid 10 for sensing.

[0027] The inductive magnetic grating 10 is elongated. During the movement of the travel shaft 6, different parts of the reading head PCB9 and the inductive magnetic grating 10 can output different inductive signals, thereby calculating the travel distance. This invention selects a smaller cylindrical travel slide rail 3 and travel shaft 6 based on the size requirements of the humanoid robot's hand. Cutting planes 8 are machined on the surfaces of the cylindrical travel slide rail 3 and travel shaft 6 to mount the reading head PCB9 and the inductive magnetic grating 10, respectively. The reading head PCB9 is embedded in the notch 301 of the travel slide rail 3, saving space and making the overall structure more compact. Furthermore, the inductive magnetic grating 10 is mounted on the travel shaft 6, which allows it to move with the travel shaft 6 without occupying the mating area of ​​the nut 4. Straightness is mainly ensured by the fit between the nut 4 and the travel slide rail 3.

[0028] Its structural composition is described below with reference to specific embodiments: Example 1 like Figures 1-6 As shown, an electric actuator for a humanoid robot includes a drive motor 1, a gearbox 2, a travel slide rail 3, a nut 4, a mounting plate 5, a travel shaft 6, and a lead screw 7. The drive motor 1 is preferably a coreless motor. The drive motor 1 and gearbox 2 are positioned by inner and outer stops and then laser-welded together. The lead screw 7 is located in the travel slide rail 3. The end of the lead screw 7 is welded to the adapter plate 11 at the front end of the gearbox 2 and supported by two bearings 2, enabling it to run smoothly after deceleration. The nut 4 is located at the front end of the gearbox 2 and meshes with the lead screw 7, converting rotational motion into linear motion. The nut 4 has an irregular shape, which mates with the irregular inner hole of the travel slide rail 3 to achieve its anti-rotation function. The irregular shape refers to a non-circular cross-section.

[0029] The travel slide rail 3 and gearbox 2 are positioned by inner and outer stops and then welded together to ensure a firm bond. The outer surface of the travel slide rail 3 is a top-cut cylindrical shape, and the top cut surface 8 is used to mount the read head PCB 9. The front end of the nut 4 is fixed to the travel shaft 6, allowing the nut 4 to drive the travel shaft 6. The outer surface of the travel shaft 6 is also a top-cut cylindrical structure, allowing the entire induction magnetic grid 10 to be attached to the cut surface 8 of the travel shaft 6.

[0030] Since this electric actuator is used for the hand of a humanoid robot, the size requirements are extremely strict. A design with an overall size of φ16mm was ultimately chosen. The drive motor 1 is a 16mm diameter hollow cup motor, ensuring maximum force while maintaining a small size. The gearbox 2 is the same size as the drive motor 1, and a 28-speed ratio two-pole gearbox 2 is selected to ensure a thin profile while providing sufficient force and appropriate speed. The lead screw 7 has a small lead of 1.27mm and a diameter of 4.77mm to ensure sufficient torque. The travel slide rail 3 uses the same cylindrical structure as the drive motor 1, with a cutting surface 8 on its surface to provide a mounting surface for the reader PCB 9. Due to the 16mm overall size requirement, the travel shaft 6 is relatively slender. Therefore, the travel shaft 6 requires a mounting plate 5 to slide and ensure the straightness of the output shaft. The outer diameter of the travel shaft 6 is optimally maintained at 8~10mm, and the width of the induction magnetic grid 10 is 3~5mm. Because the induction magnetic grid 10 needs to be installed on the travel shaft 6, the overall anti-rotation limit can only be achieved by placing it on the nut 4.

[0031] The notch 301 can be located in the middle of the travel slide rail 3 or at one end of the travel slide rail 3. In this embodiment, the notch 301 is located at one end of the travel slide rail 3 connected to the mounting plate 5.

[0032] Structure of nut 4: The nut 4 fits with the inner surface of the travel slide rail 3 to ensure reciprocating linear motion. There is no frictional contact between the travel shaft 6 and the travel slide rail 3. Therefore, the outer surface cross-sectional dimension of the nut 4 is larger than that of the travel shaft 6. To reduce the gap between the travel slide rail 3 and the travel shaft 6, the nut 4 is designed with the following structure in this embodiment: Figure 4 As shown, the cross-section of the outer circumference of the nut 4 includes symmetrically arranged first arc segments 13 and a planar segment 14 connecting the two first arc segments 13. The diameter of the first arc segment 13 is larger than the outer diameter of the travel shaft 6. The cross-sectional shape of the inner surface of the travel slide rail 3 can be partially or completely the same as the cross-sectional shape of the outer surface of the nut 4. The first arc segment 13 has a larger diameter and mates with the inner surface of the travel slide rail 3. The design of the planar segment 14 serves two purposes: firstly, to prevent rotation; and secondly, to accommodate the dimensions of the travel shaft 6, thereby reducing the gap between the travel slide rail 3 and the travel shaft 6, increasing the wall thickness of a portion of the travel slide rail 3, and ensuring structural strength. Figure 2 and Figure 3 As shown, the radial dimension of the travel shaft 6 is similar to the distance from the center of the plane segment 14 to the nut 4. The travel slide rail 3 facing the plane segment 14 has a thicker wall, while the travel slide rail 3 facing the first arc segment 13 has a thinner wall.

[0033] Connection between nut 4 and travel shaft 6: like Figure 5 As shown, the nut 4 includes a sliding fit part 401 and a threaded connection part 402. The threaded connection part 402 has an external thread for threaded connection with the stroke shaft 6 and fixed with glue. The inner circumferential surface of the sliding fit part 401 is threadedly connected to the lead screw 7, and the outer circumferential surface is in contact with the stroke slide rail 3. That is, the outer circumferential surface of the sliding fit part 401 is composed of two first arc segments 13 and two planar segments 14.

[0034] Example 2 Based on Example 1, such as Figure 7 As shown, the mounting plate 5 includes a mounting part 501 and an injection-molded body 502 fixed to the inner surface of the mounting part 501. The inner surface of the injection-molded body 502 mates with the stroke shaft 6 and the induction magnetic grating 10. The injection-molded body 502 is manufactured using injection molding, achieving high processing precision and ensuring good fit with the surfaces of the stroke shaft 6 and the induction magnetic grating 10, thus guaranteeing the linearity of movement without wear on the induction magnetic grating 10. The mounting part 501 is fixed to the stroke slide rail 3 and can be a universal component. The injection-molded body 502 can be manufactured according to the dimensions of the stroke shaft 6.

[0035] The injection body 502 can be directly injection molded into the mounting part 501, or it can be fixed to the mounting part 501 after injection molding.

[0036] In this embodiment, the injection-molded body 502 is directly injection-molded into the mounting part 501. In this case, a rib structure needs to be provided outside the injection-molded body 502 to improve the connection strength. Specifically, this means, for example... Figure 7 As shown, the outer peripheral surface of the injection-molded body 502 has annular ribs 15 and several axial ribs 16, and the inner surface of the mounting part 501 has a groove 17 for accommodating the annular ribs 15 and the axial ribs 16. After injection molding, the annular ribs 15 and the axial ribs 16 are embedded in the groove 17, which fully limits the axial and radial positioning of the injection-molded body 502, thus fixing the injection-molded body 502 to the radially inner side of the mounting part 501.

[0037] Example 3 Based on the above embodiment, the planar segment 14 also has a protruding second arc segment 18, the highest point of which is higher than the induction magnetic grid 10. The highest point of the second arc segment 18 refers to the maximum distance between the second arc segment 18 and the center of the nut 4. The second arc segment 18 contacts and engages with the inner surface of the travel slide rail 3, making the movement of the nut 4 more stable and avoiding contact friction between the induction magnetic grid 10 and the inner surface of the travel slide rail 3.

[0038] In the description of this utility model, it should be understood that the terms "center", "thickness", "inner", "outer", "axial", "radial", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0039] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be interpreted as indicating or implying relative importance.

[0040] In this specification, the illustrative expressions of the terms do not necessarily refer to the same embodiments. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments.

[0041] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. An electric actuator for a humanoid robot, characterized in that: The device includes a drive motor (1), a gearbox (2), a travel slide rail (3), a nut (4), a mounting plate (5), a travel shaft (6), and a lead screw (7). The drive motor (1), gearbox (2), travel slide rail (3), and mounting plate (5) are fixed in sequence. The lead screw (7) is connected to the motor shaft of the drive motor (1) through the gearbox (2). The nut (4) is threaded to the lead screw (7). The travel shaft (6) is located between the lead screw (7) and the travel slide rail (3) and is fixed to the nut (4). The nut (4) is located inside the travel slide rail (3) and contacts the travel slide rail (3) through a non-circular surface. The mounting plate (5) is fitted with the outer circumferential surface of the travel shaft (6). The outer peripheral surface of the travel slide rail (3) and the outer peripheral surface of the travel shaft (6) are both cylindrical surfaces with cutting planes (8). A reading head PCB (9) is installed on the cutting plane (8) of the travel slide rail (3), and an induction magnetic grid (10) extending along the running direction of the travel shaft (6) is installed on the cutting plane (8) of the travel shaft (6). The travel slide rail (3) has a notch (301) for the probe of the reading head PCB (9) to extend into, so that the probe of the reading head PCB (9) is directly in contact with the induction magnetic grid (10).

2. The electric actuator for a humanoid robot according to claim 1, characterized in that: The notch (301) is located at one end of the travel slide rail (3) connected to the mounting plate (5).

3. The electric actuator for a humanoid robot according to claim 1, characterized in that: The mounting plate (5) includes a mounting part (501) and an injection molded body (502) fixed to the inner surface of the mounting part (501). The inner surface of the injection molded body (502) cooperates with the stroke shaft (6) and the induction magnetic grid (10).

4. The electric actuator for a humanoid robot according to claim 3, characterized in that: The outer peripheral surface of the injection molded body (502) has annular ribs (15) and a plurality of axial ribs (16), and the inner surface of the mounting part (501) has a groove (17) for accommodating the annular ribs (15) and the axial ribs (16).

5. The electric actuator for a humanoid robot according to claim 1, characterized in that: The cross-section of the outer circumference of the nut (4) includes a first arc segment (13) arranged symmetrically and a plane segment (14) connecting the two first arc segments (13). The diameter of the first arc segment (13) is greater than the outer diameter of the travel shaft (6).

6. The electric actuator for a humanoid robot according to claim 5, characterized in that: The inductive magnetic grating (10) is arranged parallel to the planar segment (14), and the planar segment (14) also has a protruding second arc segment (18), the highest point of the second arc segment (18) being higher than the inductive magnetic grating (10).

7. The electric actuator for a humanoid robot according to claim 5, characterized in that: The inner surface cross section of the travel slide rail (3) is partially or entirely the same as the outer cross section of the nut (4).

8. The electric actuator for a humanoid robot according to claim 1, characterized in that: The nut (4) includes a sliding fit part (401) and a threaded connection part (402). The threaded connection part (402) is fixed to the stroke shaft (6). The inner circumferential surface of the sliding fit part (401) is connected to the lead screw (7), and the outer circumferential surface is in contact with the stroke slide rail (3).

9. The electric actuator for a humanoid robot according to claim 6, characterized in that: The distance from the plane segment (14) to the center of the nut (4) is equal to the outer diameter of the travel shaft (6).

10. The electric actuator for a humanoid robot according to claim 1, characterized in that: The outer diameter of the travel shaft (6) is 8~10mm, and the width of the induction magnetic grid (10) is 3~5mm.

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