Lead screw and actuator

Abstract

The lead screw comprises a lead screw body and a sleeve, at least part of the lead screw body is located in the sleeve, the sleeve comprises a thread part, at least part of the thread part is located on the inner side of the sleeve, the lead screw body comprises a thread matching part, the thread matching part is matched with the thread part located in the sleeve, and the thread matching part is made of plastic materials. The actuator comprises a motor and a lead screw, at least part of the lead screw is located in the motor, the lead screw comprises a lead screw body and a sleeve, the sleeve comprises a thread part, at least part of the thread part is located in the sleeve, the lead screw body comprises a thread matching part, the thread matching part is matched with the thread part located in the sleeve, and the thread matching part is made of plastic materials. The thread matching part of the lead screw is made of the plastic material, the mass of the lead screw is reduced, and therefore the mass of the lead screw and the mass of the actuator are reduced.

Description

Technical Field

[0001] This application relates to the technical field of actuators, and particularly to a lead screw and an actuator. Background Art

[0002] The actuator includes a linear actuator, which mainly consists of a motor push rod and a control mechanism, and drives the lead screw to move linearly by the rotation of the motor. In related technologies, the lead screw used in the motor push rod is made of all-metal material. Although the all-metal lead screw has high strength, it also makes the overall quality of the actuator equipped with it relatively large. Summary of the Invention

[0003] The purpose of this application is to provide a lead screw with a relatively light weight.

[0004] This application provides a lead screw, which includes a lead screw and a sleeve. At least part of the lead screw is located inside the sleeve. The sleeve includes a threaded portion, and at least part of the threaded portion is located inside the sleeve. The lead screw includes a threaded mating portion, and the threaded mating portion cooperates with the threaded portion located inside the sleeve. The threaded mating portion is made of plastic material.

[0005] Making the threaded mating portion of the lead screw from plastic material reduces the mass of the lead screw and further reduces the mass of the lead screw.

[0006] Another purpose of this application is to provide an actuator with a relatively light weight.

[0007] This application provides an actuator, which includes a motor and a lead screw. At least part of the lead screw is located inside the motor. The lead screw includes a lead screw and a sleeve. The sleeve includes a threaded portion, and at least part of the threaded portion is located inside the sleeve. The lead screw includes a threaded mating portion, and the threaded mating portion cooperates with the threaded portion located inside the sleeve. The threaded mating portion is made of plastic material.

[0008] Making the threaded mating portion of the lead screw from plastic material reduces the mass of the lead screw and further reduces the mass of the lead screw, thereby reducing the mass of the actuator. Brief Description of the Drawings

[0009] Figure 1 is a schematic structural view of the lead screw of this application;

[0010] Figure 2 is a schematic sectional view of the lead screw of this application;

[0011] Figure 3 is a schematic structural view of the lead screw of this application;

[0012] Figure 4 is a schematic structural view of the sleeve of this application;

[0013] Figure 5 is a schematic structural view of the collar of this application;

[0014] Figure 6 Structural schematic diagram of the actuator of the present application;

[0015] Figure 7 Cross-sectional schematic diagram of the actuator of the present application. Detailed implementation manners

[0016] In order to better understand the technical solution of the present application, the embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0017] It should be clear that the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0018] As Figures 1 - 5 shown, the present application provides a lead screw, the lead screw includes a screw rod 1 and a sleeve 2, at least a part of the screw rod 1 is located inside the sleeve 2, the sleeve 2 includes a threaded portion 21, at least a part of the threaded portion 21 is located inside the sleeve 2, the screw rod 1 includes a threaded mating portion 11, the threaded mating portion 11 cooperates with the threaded portion 21 located inside the sleeve 2, and the threaded mating portion 11 is made of a plastic material.

[0019] At least a part of the threaded portion 21 is located inside the sleeve 2. In the present application, the threaded portion 21 includes an internal threaded section 211 and an external threaded section 212. The internal threaded section 211 is defined as the thread located inside the sleeve 2, and the external threaded section 212 is defined as the thread located outside the sleeve 2. The threaded mating portion 11 of the screw rod 1 is located outside the screw rod 1. In this way, the screw rod 1 is threadedly connected to the internal threaded section 211 of the sleeve 2 through the threaded mating portion 11. When the sleeve 2 rotates, the sleeve 2 will drive the screw rod 1 to perform a linear reciprocating motion. In the related art, in order to ensure the strength of the screw rod, most screw rods are made of a metal material. However, the screw rod made of a metal material has a relatively large mass, and some products that use a lead screw to achieve linear motion need to meet the requirement of light weight. In the present application, the threaded mating portion of the screw rod is made of a plastic material. The screw rod partially made of plastic is lighter in mass than the fully metal screw rod, and can achieve the light weight of the product. The plastic material in the present application uses a special plastic with excellent thermal stability and mechanical properties, such as PEEK (polyetheretherketone), PPS (polyphenylene sulfide), PEI (polyetherimide), etc.

[0020] Wherein, the threaded portion 21 includes an internal thread section 211 which is located inside the sleeve 2. The threaded mating portion 11 is located outside the lead screw 1, and the length of the threaded mating portion 11 is less than that of the internal thread section 211. The lead screw 1 includes a rod portion 12, and the threaded mating portion 11 is connected to the rod portion 12. The rod portion 12 is made of a metal material or a plastic material.

[0021] Here, the rod portion 12 of the lead screw 1 can be made of plastic or metal. When the rod portion 12 of the lead screw 1 is made of plastic, the entire lead screw is made of plastic, so that the overall mass of the lead screw is relatively light, further realizing the lightweight of the products using such lead screws. When the rod portion of the lead screw is made of metal, with such a setting that the threaded mating portion of the lead screw is made of plastic and the rod portion is made of metal, for the lead screw combining plastic and metal, compared with the lead screw made of an overall metal material, the plastic threaded mating portion can reduce the mass of the lead screw, while the metal rod portion can ensure the strength of the lead screw. Thus, when it is necessary to use the lead screw for traction and other behaviors, the strength of the lead screw can also be improved to prevent the lead screw from breaking. For example, for the lead screws applied in the fields of home appliances, medical treatment, vehicles, etc., the lead screw is made of metal material to ensure the strength of the lead screw itself, so as to ensure that the actuator and other actuating components that realize linear motion by assembling the lead screw can work stably. However, blindly using an all-metal material, although solving the strength problem of the device, will also bring the problem of excessive mass, which brings disadvantages to some products that require light weight. The excessive mass may cause these products to be overloaded and thus limit the usage scenarios of the products. For example, for humanoid robots, linear actuators are used at the single-degree-of-freedom joints of the limbs of humanoid robots to provide linear motion, and the lead screw is a core component of the linear actuator. By using the lead screw made of the plastic material provided in this application or the lead screw compounded with technical materials, its use strength can be guaranteed. In this way, compared with the lead screw made of an all-metal material, the lead screw provided in this application reduces the mass of the actuator, thus realizing the lightweight of the humanoid robot. In the related art, one end of the rod portion of the lead screw far from the threaded mating portion is connected to other parts that need to be pulled, and the linear movement distance of the lead screw is related to the number of rotation turns of the sleeve, that is, by reasonably setting the rotation amount of the sleeve, the preset linear movement distance of the lead screw can be obtained. The linear displacement stroke of the lead screw is related to the difference between the internal thread length of the sleeve and the external thread length of the lead screw. If a longer linear displacement distance of the lead screw is desired, then when the internal thread length of the sleeve is fixed, the external thread length of the lead screw should be smaller. In this way, when the sleeve rotates, under the cooperation of the threaded mating portion of the lead screw and the internal thread of the sleeve, the movement distance of the lead screw moving linearly along the internal thread path of the sleeve will be as long as possible. Such as Figure 1 、 Figure 2 、 Figure 4 、 Figure 5As shown, the sleeve 2 has a magnetic conductive region D. The sleeve 2 includes an outer wall 22, and at least part of the magnetic conductive region D is located on the outer wall 22. In the related art, most often an electric motor is used to drive the rotation of the sleeve. The electric motor includes a stator and a rotor. When current is conducted through the stator, a stator magnetic field is generated. The stator magnetic field can induce the rotor and thus generate a rotor magnetic field in the rotor. The interaction between the stator magnetic field and the rotor magnetic field causes the rotor to start rotating. To ensure that the electric motor can drive the lead screw well, the electric motor is generally assembled on the radial outside of the sleeve, and the magnetic tile of the rotor is attached to the outer wall of the sleeve. Here, to ensure that the power loss is as small as possible, a magnetic conductive region is provided on the outer wall of the sleeve, and the magnetic tile of the rotor is attached to the magnetic conductive region. In this way, when the electric motor is powered on, the rotor drives the sleeve to rotate, and the sleeve drives the lead screw that is threadedly connected thereto to move linearly.

[0022] Specifically, the sleeve 2 includes a ring sleeve 23, and at least part of the magnetic conductive region D is located on the ring sleeve 23. The ring sleeve 23 is made of a magnetic conductive material. The sleeve 2 further includes a cylinder body 24. The ring sleeve 23 is sleeved on the outside of the cylinder body 24. The threaded portion 21 is located on the cylinder body 24, and the cylinder body 24 is made of a plastic material. In this application, the sleeve 2 includes a ring sleeve 23 and a cylinder body 24. The ring sleeve 23 is sleeved on the outside of the cylinder body 24. Part of the magnetic conductive region D of the sleeve 2 is located on the ring sleeve 23, and the magnetic tile of the rotor is attached to the outer wall of the ring sleeve 23. In this way, to minimize the power loss as much as possible, the sleeve is made of a magnetic conductive material. The ring sleeve 23 is sleeved on the outside of the cylinder body 24, and part of the cylinder body 24 is located inside the ring sleeve 23. The cylinder body 24 is located radially inside the ring sleeve 23, and the threaded portion 21 is located on the cylinder body 24. The threaded portion 21 includes an internal threaded section 211 and an external threaded section 212. The internal threaded section 211 is located inside the cylinder body 24. To reduce the mass of the lead screw, the cylinder body 24 is made of a plastic material. Using a plastic material for the threaded portion can reduce the friction coefficient. In this way, the plastic cylinder body 24 is combined with the magnetic conductive ring sleeve 23, which not only ensures that the sleeve can rotate with the drive of the electric motor while minimizing the power loss as much as possible, but also further reduces the mass of the lead screw, enabling some products using such lead screws to achieve lightweight. Here, the ring sleeve 23 and the cylinder body 24 can be integrated or separated. When the ring sleeve 23 and the cylinder body 24 are in an integrated form, the plastic cylinder body 24 can be formed by injection molding on the inner side of the ring sleeve 23. When the ring sleeve 23 and the cylinder body 24 are in a separated form, other connection methods such as interference fit or threading can be used to connect the ring sleeve 23 and the cylinder body 24 together. The connection method is not limited here. The magnetic conductive material mentioned here refers to a material with magnetic conductive function, including metal materials and non-metal materials.

[0023] Of course, there is also a situation where the sleeve 2 is made of plastic material, and the collar 23 is made of plastic with a magnetic conductive component, that is, the collar 23 is made of plastic material with a magnetic conductive component. Since the magnetic tile needs to be attached to the outer side of the collar 23, and the attachment area of the magnetic tile needs to have a magnetic conduction function, it is only necessary to ensure that the material of the collar 23 has a magnetic conductive component to achieve the magnetic conduction function. And if the whole sleeve is made of plastic material, different plastic materials can be used in different areas or different structures of the sleeve, which can further reduce the mass of the lead screw as a whole. When the whole sleeve and the lead screw are made of plastic material, it means that the whole lead screw is made of plastic material. Such a setting is the optimal solution for reducing the mass of the lead screw and is convenient for realizing the lightweight of the products equipped with such lead screws. It should be noted here that although both the sleeve and the lead screw are made of plastic material, a magnetic conductive component will be added to the magnetic conductive area inside the sleeve. That is, although the sleeve is made of plastic material, in order to ensure different functions in different areas, the plastic materials at different positions of the sleeve may not be of the same type. For example, the magnetic conductive area requires plastic material with a magnetic conductive component, and the positions with requirements for strength use plastic material with stronger strength.

[0024] As Figure 5 shown, the collar 23 includes concave-convex portions 231, and the concave-convex portions 231 are located inside the collar 23. Since the collar 23 is located outside the cylinder body 24, and the collar 23 is made of a magnetic conductive material and the cylinder body 24 is made of plastic material, preferably, the collar 23 is made of a metal magnetic conductive material. When the plastic cylinder body 24 is combined with the metal collar 23, the concave-convex portions 231 inside the cylinder body 24 facilitate enhancing the bonding strength between the plastic and the metal. Specifically, the concave-convex portions 231 can be in the shape of a sawtooth, a polygon, etc. The setting of the concave-convex portions 231 is also used to increase the surface roughness of the inner side wall of the collar 23 to strengthen the bonding strength between the collar and the cylinder body with different materials.

[0025] As Figures 6 - 7As shown in the figure, an actuator includes a motor 3 and a lead screw. At least part of the lead screw is located inside the motor 3. The lead screw includes a screw rod 1 and a sleeve 2. The sleeve 2 includes a threaded portion 21. At least part of the threaded portion 21 is located inside the sleeve 2. The screw rod 1 includes a threaded mating portion 11. The threaded mating portion 11 mates with the threaded portion 21 located inside the sleeve 2. The threaded mating portion 11 is made of plastic material. The threaded portion 21 includes an internal thread section 211. The internal thread section 211 is located inside the sleeve 2. The threaded mating portion 11 is located outside the screw rod 1. The length of the threaded mating portion 11 is less than the length of the internal thread section 211. The screw rod 1 includes a rod portion 12. The threaded mating portion 11 is connected to the rod portion 12. The rod portion 12 is made of metal material, or the rod portion 12 is made of plastic material. The motor 3 includes a stator 31 and a rotor 32. The lead screw has a magnetic conductive region D. The sleeve 2 includes an outer wall 22. At least part of the magnetic conductive region D is located on the outer wall 22. The rotor 32 is arranged in the magnetic conductive region D. The rotor 32 is connected to the outer wall 22 located in the magnetic conductive region D. The stator 31 is located around the rotor 32. The sleeve 2 includes a collar 23. At least part of the magnetic conductive region D is located on the collar 23. The collar 23 is made of magnetic conductive material. The sleeve 2 includes a cylinder body 24. The collar 23 is sleeved outside the cylinder body 24. The cylinder body 24 is made of plastic material.

[0026] The actuator proposed in this application includes a motor 3 and a lead screw. The motor 3 is arranged outside the lead screw. The motor 3 includes a stator 31 and a rotor 32. When current passes through the stator 31, a stator magnetic field is generated. The stator magnetic field induces the rotor 32 and then a rotor magnetic field is generated in the rotor 32. The stator magnetic field and the rotor magnetic field interact to make the rotor start to rotate. The magnetic tile of the rotor 32 is attached to the magnetic conductive region D on the outer wall of the sleeve 2. In this way, when the motor is powered on, the rotor 32 drives the sleeve 2 to rotate, and the sleeve 2 drives the screw rod that is threadedly connected to it to move linearly. Since the linear movement distance of the screw rod is related to the number of rotation turns of the sleeve, that is, by reasonably setting the rotation amount of the sleeve, a preset linear movement distance of the screw rod can be obtained. The linear movement distance of the screw rod is related to the difference between the internal thread length of the sleeve and the external thread length of the screw rod. If a longer linear displacement distance of the screw rod is desired, then when the internal thread length of the sleeve is fixed, the external thread length of the screw rod should be smaller. In this way, when the sleeve rotates, under the cooperation of the threaded mating portion of the screw rod and the internal thread of the sleeve, the moving distance of the screw rod moving linearly along the internal thread path of the sleeve will be as long as possible.

[0027] The rod portion 12 of the lead screw 1 of the present application can be made of plastic or metal. When the rod portion 12 of the lead screw 1 is made of plastic, the entire lead screw is made of plastic, so that the overall quality of the lead screw is relatively light. When the rod portion of the lead screw is made of metal, the threaded mating portion of the lead screw is made of plastic and the rod portion is made of metal. For a lead screw combining plastic and metal, compared with a lead screw made entirely of metal, the plastic threaded mating portion can reduce the mass of the lead screw, while the metal rod portion can ensure the strength of the lead screw.

[0028] The collar 23 is sleeved on the outside of the cylinder 24. Part of the cylinder 24 is located inside the collar 23. The cylinder 24 is located radially inside the collar 23, and the threaded portion 21 is located on the cylinder 24. The threaded portion 21 includes an internal thread section 211 and an external thread section 212. The internal thread section 211 is located inside the cylinder 24. To reduce the mass of the lead screw, the cylinder 24 is made of plastic. Using plastic for the threaded portion can reduce the friction coefficient. Thus, the plastic cylinder 24 is paired with a collar 23 made of a magnetic conductive material, which not only ensures that the sleeve can rotate with the motor drive while minimizing power loss, but also further reduces the mass of the lead screw, enabling some products equipped with such lead screws to achieve lightweight. Here, the collar 23 and the cylinder 24 can be integral or separate. When the collar 23 and the cylinder 24 are in an integral form, the plastic cylinder 24 can be formed by injection molding on the inner side of the collar 23. When the collar 23 and the cylinder 24 are in a separate form, other connection methods such as interference fit or threading can be used to connect the collar 23 and the cylinder 24 together. The connection method is not limited here. The magnetic conductive material here of course also includes metal materials and non-metal materials.

[0029] Of course, there is also a case where the sleeve 2 is entirely made of plastic, and the collar 23 is made of plastic with a magnetic conductive component, that is, the collar 23 is made of plastic material with a magnetic conductive component, and the cylinder 24 is made of plastic material. Since the magnetic tile needs to be attached to the outside of the collar 23, it only needs to ensure that the material of the collar 23 has a magnetic conductive component and can achieve the magnetic conduction function. Making the entire sleeve of plastic material can further reduce the overall mass of the lead screw. When the entire sleeve is made of plastic material and the entire lead screw is made of plastic material, it means that the entire lead screw is made of plastic material. Such a setting is the optimal solution for reducing the mass of the lead screw and facilitating the lightweight of products equipped with such lead screws. It should be noted here that although both the sleeve and the lead screw are made of plastic material, a magnetic conductive component will be added to the magnetic conductive area inside the sleeve. That is, although the sleeve is made of plastic material, to ensure different functions in different regions, the plastic materials at different positions of the sleeve may not be of the same type. For example, the magnetic conductive area requires plastic material with a magnetic conductive component, and positions with requirements for strength use plastic material with stronger strength.

[0030] The above embodiments are only used to illustrate the present application and do not limit the technical solutions described in the present application. The understanding of this specification should be based on those skilled in the art. For example, the directional descriptions such as "front", "rear", "left", "right", "upper", "lower", etc. are only used to describe the relationship between objects and are not substantive limitations. "Multiple" means at least two or more.

[0031] Although this specification has described the present application in detail with reference to the above embodiments, those of ordinary skill in the art should understand that those skilled in the art can still modify or equivalently replace the present application, and all technical solutions and their improvements that do not depart from the spirit and scope of the present application should be covered within the scope of the claims of the present application.

Claims

1. A lead screw, characterized in that, The lead screw includes a screw rod (1) and a sleeve (2). The screw rod (1) is at least partially located inside the sleeve (2). The sleeve (2) includes a threaded portion (21), and the threaded portion (21) is at least partially located inside the sleeve (2). The screw rod (1) includes a threaded mating portion (11), and the threaded mating portion (11) mates with the threaded portion (21) located inside the sleeve (2). The threaded mating portion (11) is made of plastic material.

2. The lead screw according to claim 1, wherein, The sleeve (2) has a magnetic conductive region (D). The sleeve (2) includes an outer wall (22), and the magnetic conductive region (D) is at least partially located on the outer wall (22).

3. The lead screw according to claim 2, characterized in that, The sleeve (2) includes a collar (23), and the magnetic conductive region (D) is at least partially located on the collar (23). The collar (23) is made of magnetic conductive material.

4. The lead screw according to claim 3, characterized in that, The sleeve (2) further includes a cylinder body (24). The collar (23) is sleeved on the outside of the cylinder body (24). The threaded portion (21) is located on the cylinder body (24). The cylinder body (24) is made of plastic material.

5. The lead screw according to claim 3, characterized in that, The collar (23) includes uneven portions (231), and the uneven portions (231) are located inside the collar (23).

6. The lead screw according to any one of claims 1-5, characterized in that, The threaded portion (21) includes an internal thread section (211). The internal thread section (211) is located inside the sleeve (2). The threaded mating portion (11) is located on the outside of the screw rod (1). The length of the threaded mating portion (11) is less than the length of the internal thread section (211).

7. The lead screw according to claim 6, wherein, The screw rod (1) includes a rod portion (12). The threaded mating portion (11) is connected to the rod portion (12). The rod portion (12) is made of metal material, or the rod portion (12) is made of plastic material.

8. An actuator, characterized in that, It includes a motor (3) and a lead screw. The lead screw is at least partially located inside the motor (3). The lead screw includes a screw rod (1) and a sleeve (2). The sleeve (2) includes a threaded portion (21), and the threaded portion (21) is at least partially located inside the sleeve (2). The screw rod (1) includes a threaded mating portion (11), and the threaded mating portion (11) mates with the threaded portion (21) located inside the sleeve (2). The threaded mating portion (11) is made of plastic material.

9. The actuator according to claim 8, characterized in that, The motor (3) includes a stator (31) and a rotor (32). The lead screw has a magnetic conductive region (D). The sleeve (2) includes an outer wall (22), and the magnetic conductive region (D) is at least partially located on the outer wall (22). The rotor (32) is arranged inside the magnetic conductive region (D), and the rotor (32) is connected to the outer wall (22) located inside the magnetic conductive region (D). The stator (31) is located on the periphery of the rotor (32).

10. The actuator according to claim 9, characterized in that, The sleeve (2) includes a collar (23), and the magnetic conductive region (D) is at least partially located on the collar (23). The collar (23) is made of magnetic conductive material.

11. The actuator according to claim 10, characterized in that, The sleeve (2) includes a cylinder body (24). The collar (23) is sleeved on the outside of the cylinder body (24). The cylinder body (24) is made of plastic material.

12. The actuator according to any one of claims 8-11, characterized in that, The threaded portion (21) includes an internal thread section (211), the internal thread section (211) is located inside the sleeve (2), the thread mating portion (11) is located outside the lead screw (1), and the length of the thread mating portion (11) is less than the length of the internal thread section (211).

13. The actuator according to claim 12, wherein, The lead screw (1) includes a rod portion (12), the thread mating portion (11) is connected to the rod portion (12), and the rod portion (12) is made of a metal material, or the rod portion (12) is made of a plastic material.

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