Differential planetary roller screw transmission device

Abstract

The invention provides a differential planetary roller screw transmission device, and belongs to the technical field of roller screws. The device comprises a sleeve; a central lead screw; the planetary rotating assemblies are located in the mounting cavity and arranged around the center lead screw, each planetary rotating assembly comprises a connecting shaft, a first pin roller, a first adjusting gasket, a positioning rolling body, a second adjusting gasket and a second pin roller, the connecting shaft is sequentially sleeved with the first pin roller, the first adjusting gasket, the positioning rolling body, the second adjusting gasket and the second pin roller, and the two ends of the first adjusting gasket abut against the first pin roller and the positioning rolling body correspondingly; the two ends of the second adjusting gasket abut against the positioning rolling body and the second pin roller correspondingly, and the first pin roller and the second pin roller are connected with the center lead screw through lead screw pairs correspondingly. The positioning assembly comprises a first positioning ring and a second positioning ring which are fixedly arranged on the sleeve, and the first positioning ring and the second positioning ring jointly form a positioning face used for limiting and positioning the rolling body in the axial direction. High-precision output of the device can be guaranteed, and abnormal sound caused by tooth dislocation is avoided.

Description

Technical Field

[0001] This application relates to the technical field of ball screws, and in particular to a differential planetary ball screw drive device. Background Art

[0002] The differential planetary ball screw mechanism uses the differential principle to achieve high-precision displacement output, and is often applied to high-precision fields, such as precision robots, semiconductor manufacturing equipment and other fields.

[0003] Two sets of roller assemblies spaced axially in the differential planetary ball screw mechanism are usually connected to a shaft body, and are end-limited by a positioning ring on the side away from each other. The two sets of roller assemblies maintain an axial distance through cooperation with the screw. However, during use, the axial distance between the two sets of roller assemblies may change, resulting in a decrease in output accuracy, and the change in the relative position between the screw and the roller assembly will also cause abnormal noise, thus limiting the high-precision use scenarios of the differential planetary ball screw mechanism. Summary of the Invention

[0004] An object of the present invention is to provide a differential planetary ball screw drive device, which can ensure the high-precision output of the device and avoid abnormal noise caused by tooth misalignment.

[0005] Another object of the present invention is to improve the applicable range of the product of the solution.

[0006] A further object of the present invention is to simplify the assembly process.

[0007] An embodiment of the present invention provides a differential planetary ball screw drive device, including:

[0008] A sleeve having an axially penetrating installation cavity;

[0009] A central screw disposed in the installation cavity;

[0010] A plurality of planetary rotating components located in the installation cavity and arranged around the central screw. Each planetary rotating component includes a connecting shaft and a first roller, a first adjusting gasket, a positioning rolling body, a second adjusting gasket and a second roller sequentially sleeved on the connecting shaft. Two ends of the first adjusting gasket are respectively abutted against the first roller and the positioning rolling body, two ends of the second adjusting gasket are respectively abutted against the positioning rolling body and the second roller, the first roller and the second roller are respectively connected to the central screw through a screw pair, and a gap is provided between the positioning rolling body and the central screw;

[0011] The positioning component includes a first positioning ring and a second positioning ring both fixedly arranged on the sleeve, and the first positioning ring and the second positioning ring jointly form a positioning surface for axially positioning the positioning rolling elements.

[0012] Optionally, the first adjusting gasket and the second adjusting gasket are set to be replaceable, and the axial lengths of different first adjusting gaskets and / or different second adjusting gaskets are different.

[0013] Optionally, the positioning surface is a spherical surface.

[0014] Optionally, positioning planes perpendicular to the axis are arranged on both axial sides of the positioning rolling elements.

[0015] Optionally, the positioning rolling elements are set to be replaceable, and the axes of the axial holes for passing through the connecting shaft of different positioning rolling elements have different angles with the positioning planes.

[0016] Optionally, the positioning rolling elements are formed by machining spherical balls, and the two positioning planes are symmetric with respect to the sphere center plane of the sphere, and the sphere center plane is a plane passing through its center of the sphere and parallel to the positioning plane.

[0017] Optionally, the first positioning ring and the second positioning ring are symmetrically arranged along the sphere center plane of the positioning rolling elements.

[0018] Optionally, a spacer is further arranged between adjacent positioning rolling elements for positioning adjacent planetary rotation components.

[0019] Optionally, both ends of the spacer are respectively abutted against the first roller and the second roller.

[0020] According to the first aspect of the present invention, a differential planetary roller screw drive device with an axial clearance positioning function realizes the connection between the planetary rotation component and the sleeve through arranging positioning rolling elements, a first adjusting gasket and a second adjusting gasket between the first roller and the second roller, and realizes the connection through the positioning rolling elements and a positioning component fixed on the sleeve. The axial clearance between the first roller and the second roller is ensured by the first adjusting gasket and the second adjusting gasket, so that the axial distance between the first roller and the second roller can accurately match the teeth on the screw, thereby ensuring the high-precision output of the device and avoiding abnormal noises caused by tooth misalignment, enabling the above differential planetary roller screw drive device to be used in application scenarios with higher precision requirements and ensuring the stability of the output precision.

[0021] Further, the first roller and the second roller can be press-fitted to the connecting shaft. During assembly, as long as the first roller is moved to a position where it abuts against the first adjusting shim and the second roller is moved to a position where it abuts against the second adjusting shim, there is no need to provide a positioning member on the side where the first roller and the second roller are away from each other.

[0022] According to the second aspect of the present invention, the first adjusting shim and the second adjusting shim are arranged to be replaceable. Therefore, when wear occurs due to long-term use, new adjusting shims can be replaced. In addition, for different models of differential planetary roller screw drive devices, if the axial clearances of the first roller and the second roller are different, the positioning method of the present application can still be adopted, and only the first adjusting shim and the second adjusting shim with corresponding lengths need to be replaced, thereby improving the applicable range of the product of the solution.

[0023] According to the third aspect of the present invention, by providing positioning planes on both sides of the positioning rolling elements, the first adjusting shim and the second adjusting shim can abut more stably on both sides of the positioning rolling elements. The setting of the two positioning planes causes a clearance between the first adjusting shim and the second adjusting shim and the connecting shaft, and there will be no axial length, that is, the axial clearance between the first roller and the second roller can still be ensured. And when there is a clearance between the first adjusting shim and the second adjusting shim and the connecting shaft, the assembly can be made easier.

[0024] Further, when the positioning rolling elements are arranged to be symmetric with respect to the sphere center plane, the first positioning ring and the second positioning ring are symmetric with respect to the sphere center plane, which can ensure uniform force in both axial positive and negative directions, and enables the first positioning ring and the second positioning ring to adopt the same parts, and only the orientation needs to be noted during assembly.

[0025] According to the fourth aspect of the present invention, by providing a separating member to separate the positioning rolling elements, the function of circumferentially positioning each planetary rotating component can be achieved. The end faces of the first roller and the second roller are used for axial positioning of the separating member, so there is no need to separately provide an axial positioning member, which can reduce the number of parts and simplify the installation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a cross-sectional view of a differential planetary roller screw drive device according to an embodiment of the present invention;

[0027] Figure 2 is Figure 1 a cross-sectional view of the differential planetary roller screw drive device in

[0028] Reference Signs:

[0029] 100 - Differential planetary roller screw drive device, 10 - Sleeve, 101 - Installation cavity, 20 - Central screw, 30 - Planetary rotation assembly, 31 - Connecting shaft, 32 - First roller, 33 - First adjusting gasket, 34 - Positioning rolling element, 341 - Positioning plane, 35 - Second adjusting gasket, 36 - Second roller, 40 - Positioning assembly, 41 - First positioning ring, 42 - Second positioning ring, 401 - Positioning surface, 50 - Spacer. Detailed implementation manners

[0030] To make the above - mentioned objects, features, and advantages of the present application more obvious and understandable, the following will describe the detailed implementation manners of the present application with reference to the accompanying drawings. Many specific details are set forth in the following description to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present application. Therefore, the present application is not limited by the specific embodiments disclosed below.

[0031] It should be noted that when a component is referred to as "fixed to" or "disposed on" another component, it can be directly on the other component or there can also be an intermediate component. When a component is considered to be "connected" to another component, it can be directly connected to the other component or there may be an intermediate component at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in the description of this application are only for the purpose of illustration and do not represent the only implementation manner.

[0032] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of this application, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0033] In this application, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature can be that the first feature is in direct contact with the second feature, or the first feature and the second feature are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below" and "beneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the first feature has a lower horizontal height than the second feature.

[0034] Unless otherwise defined, all technical and scientific terms used in the specification of this application have the same meaning as commonly understood by those skilled in the technical field to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used in the specification of this application includes any and all combinations of one or more of the related listed items.

[0035] Figure 1 FIG. 4 is a cross-sectional view of a differential planetary roller screw drive device 100 according to an embodiment of the present invention. In one embodiment, as Figure 1 shown, the differential planetary roller screw drive device 100 includes a sleeve 10, a central screw 20, a plurality of planetary rotating components 30, and a positioning component 40. The sleeve 10 has an axially penetrating installation cavity 101. The central screw 20 is disposed in the installation cavity 101. The plurality of planetary rotating components 30 are located in the installation cavity 101 and are arranged around the central screw 20. Generally, the respective planetary rotating components 30 are evenly distributed along the circumferential direction of the screw. Each planetary rotating component 30 includes a connecting shaft 31, and a first roller 32, a first adjusting gasket 33, a positioning rolling body 34, a second adjusting gasket 35, and a second roller 36 sleeved on the connecting shaft 31 in sequence. Both ends of the first adjusting gasket 33 are respectively abutted against the first roller 32 and the positioning rolling body 34. Both ends of the second adjusting gasket 35 are respectively abutted against the positioning rolling body 34 and the second roller 36. A screw pair connection is respectively provided between the first roller 32 and the second roller 36 and the central screw 20. A gap is provided between the positioning rolling body 34 and the central screw 20, that is to say, the positioning rolling body 34 is not in contact with the central screw 20. Here, the gap only needs to ensure that the positioning rolling body 34 and the central screw 20 are not in contact. The positioning component 40 includes a first positioning ring 41 and a second positioning ring 42 both fixedly disposed on the sleeve 10, and the fixing method can be interference connection. The first positioning ring 41 and the second positioning ring 42 jointly form a positioning surface 401 for axially defining the positioning rolling body 34. As Figure 1 shown in the embodiment, spherical surfaces are respectively provided at the first positioning ring 41 and the second positioning ring 42, and the two spherical surfaces jointly form the positioning surface 401. Correspondingly, the contact surface between the positioning rolling body 34 and the positioning surface 401 is also set to a matching spherical surface. Of course, in other embodiments not shown, the positioning surface 401 can also be an inclined surface. The surface of the positioning rolling body 34 in contact with the positioning surface 401 can be a matching surface of the same shape or a non-matching surface. For example, when the positioning surface 401 is a spherical surface, the surface of the positioning rolling body 34 in contact with the positioning surface 401 is an inclined surface. Here, as long as the positioning surface 401 can play the role of axially defining the positioning rolling body 34. The first positioning ring 41, the second positioning ring 42, and the positioning rolling body 34 here can be made of wear-resistant bearing steel material.

[0036] When using the above differential planetary roller screw drive device 100, the central screw 20 can be used as the input end, and the sleeve 10 can be used as the output end. The central screw 20 is driven by a driving source to output a linear displacement. Of course, the driving source can also be connected to the sleeve 10, and the central screw 20 can be used as the output end, which is not limited here. In some other embodiments, the device can also be used as a motion conversion mechanism in a transmission system, that is, converting the upstream rotation into linear motion for output, or converting the upstream linear motion into rotation for output. The usage scenarios of the differential planetary roller screw drive device 100 are not limited here.

[0037] This embodiment provides a differential planetary roller screw drive device 100 with an axial clearance positioning function. By arranging a positioning rolling element 34, a first adjusting gasket 33, and a second adjusting gasket 35 between the first roller 32 and the second roller 36, the planetary rotation assembly 30 is connected to the sleeve 10 through the positioning rolling element 34 and a positioning assembly 40 fixed to the sleeve 10. The axial clearance between the first roller 32 and the second roller 36 is ensured by the first adjusting gasket 33 and the second adjusting gasket 35, so that the axial distance between the first roller 32 and the second roller 36 can accurately match the teeth on the screw, thereby ensuring the high-precision output of the device and avoiding abnormal noises caused by tooth misalignment, enabling the above differential planetary roller screw drive device 100 to be used in scenarios with higher precision requirements and ensuring the stability of the output precision.

[0038] In one embodiment, the first roller 32 and the second roller 36 can be press-fitted onto the connecting shaft 31. During assembly, as long as the first roller 32 is moved to a position where it abuts against the first adjusting gasket 33, and the second roller 36 is moved to a position where it abuts against the second adjusting gasket 35, there is no need to provide a positioning member on the side where the first roller 32 and the second roller 36 are away from each other.

[0039] In a further embodiment, the first adjusting gasket 33 and the second adjusting gasket 35 are set to be replaceable, and the axial lengths of different first adjusting gaskets 33 and / or different second adjusting gaskets 35 are different.

[0040] The first adjusting gasket 33 and the second adjusting gasket 35 in this embodiment are set to be replaceable. Therefore, when wear occurs after a long time of use, new adjusting gaskets can be replaced. In addition, for different models of the differential planetary roller screw drive device 100, if the axial clearances between the first roller 32 and the second roller 36 are different, the positioning method of this application can still be adopted here, and only the first adjusting gasket 33 and the second adjusting gasket 35 with corresponding lengths need to be replaced, thereby improving the applicable range of the solution product.

[0041] In one embodiment, positioning planes 341 perpendicular to the axial direction are provided on both axial sides of the positioning rolling element 34. For example, the positioning rolling element 34 is formed by machining a sphere, that is, two parallel and symmetrical positioning planes 341 are cut out at the sphere. In one embodiment, the two positioning planes 341 are symmetrical with respect to the sphere center plane, and the sphere center plane is a plane passing through its center of the sphere and parallel to the positioning plane 341. The first positioning ring 41 and the second positioning ring 42 are symmetrically arranged along the sphere center plane of the positioning rolling element 34.

[0042] In this embodiment, by providing the positioning planes 341 on both sides of the positioning rolling element 34, the first adjusting gasket 33 and the second adjusting gasket 35 can abut more stably on both sides of the positioning rolling element 34. The setting of the two positioning planes 341 enables a gap to exist between the first adjusting gasket 33 and the second adjusting gasket 35 and the connecting shaft 31, and no axial length will be generated, that is, the axial gap between the first roller 32 and the second roller 36 can still be ensured. When a gap exists between the first adjusting gasket 33 and the second adjusting gasket 35 and the connecting shaft 31, the assembly can be made easier.

[0043] Furthermore, when the positioning rolling element 34 is set to be symmetrical with respect to the sphere center plane and the first positioning ring 41 and the second positioning ring 42 are symmetrical with respect to the sphere center plane, it can be ensured that the forces in both the axial positive and negative directions are evenly distributed, and the first positioning ring 41 and the second positioning ring 42 can use the same parts, and only the orientation needs to be noted during assembly.

[0044] In one embodiment, the positioning rolling element 34 is set to be replaceable, and the angles between the axial directions of the axial holes for passing through the connecting shaft 31 of different positioning rolling elements 34 and the positioning plane 341 are different.

[0045] That is to say, this embodiment provides a series of positioning rolling elements 34 with different axial directions of the axial holes. In some use scenarios, due to processing accuracy and assembly accuracy problems, the tooth surfaces of the first roller 32 and the second roller 36 may not match the tooth surface of the lead screw, for example, there is a small included angle. At this time, a connecting shaft 31 that can adjust this included angle can be selected to eliminate the included angle at the connection pair of the roller and the lead screw, thereby playing a role in adjusting the angle of the matching surface and improving the fitting accuracy.

[0046] In order to achieve circumferential positioning between the respective planetary rotation assemblies 30, the present application also provides a circumferential positioning member.

[0047] Figure 2 For Figure 1 the sectional view of the differential planetary roller screw drive device 100 along the A-A sectional line. As Figure 2As shown, in one embodiment, a spacer 50 is further provided between adjacent positioning rolling elements 34 for positioning adjacent planetary rotating assemblies 30. For example, the spacer 50 is a cylindrical rod made of self-lubricating PEEK to adapt to the rotational movement scenario. Further, both ends of the spacer 50 are respectively in contact with the first roller 32 and the second roller 36, that is, the axial positioning of the spacer 50 is achieved through the first roller 32 and the second roller 36. For example, when the positioning rolling element 34 is a spherical workpiece, the diameter of the sphere is smaller than that of the first roller 32 and the second roller 36. At this time, the diameter difference can be utilized to respectively contact both ends of the spacer 50 with the end faces of the first roller 32 and the second roller 36. In other embodiments, other positioning structures can also be adopted. For example, both ends of the spacer 50 extend out of the end faces of the first roller 32 and the second roller 36 that are away from each other, and positioning rings are further provided on the sides where the first roller 32 and the second roller 36 are away from each other for the axial positioning of the spacer 50, which will not be limited here.

[0048] In this embodiment, by providing the spacer 50 to separate the positioning rolling elements 34, the function of circumferentially positioning each planetary rotating assembly 30 can be achieved. The axial positioning of the spacer 50 is carried out by using the end faces of the first roller 32 and the second roller 36. Therefore, there is no need to separately provide an axial positioning member, which can reduce the number of parts and simplify the installation process.

[0049] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A differential planetary roller screw drive device, characterized in that, Comprising: A sleeve having an axially penetrating mounting cavity; A central lead screw disposed within the mounting cavity; A plurality of planetary rotation assemblies located within the mounting cavity and arranged around the central lead screw. Each planetary rotation assembly includes a connecting shaft and a first roller, a first adjusting spacer, a positioning rolling body, a second adjusting spacer, and a second roller sequentially sleeved on the connecting shaft. Both ends of the first adjusting spacer are respectively in contact with the first roller and the positioning rolling body. Both ends of the second adjusting spacer are respectively in contact with the positioning rolling body and the second roller. A lead screw pair is provided between the first roller and the second roller and the central lead screw respectively, and a gap is provided between the positioning rolling body and the central lead screw; A positioning assembly including a first positioning ring and a second positioning ring both fixedly provided on the sleeve. The first positioning ring and the second positioning ring jointly form a positioning surface for axially positioning the positioning rolling body.

2. The differential planetary roller screw drive device according to claim 1, characterized in that, The first adjusting spacer and the second adjusting spacer are provided to be replaceable, and the axial lengths of different first adjusting spacers and / or different second adjusting spacers are different.

3. The differential planetary roller screw drive device according to claim 1, characterized in that, The positioning surface is a spherical surface.

4. The differential planetary roller screw drive device according to claim 1, characterized in that, Positioning planes perpendicular to the axis are provided on both sides of the positioning rolling body in the axial direction.

5. The differential planetary roller screw drive device according to claim 4, characterized in that The positioning rolling body is provided to be replaceable, and the axes of the axial holes for passing through the connecting shaft of different positioning rolling bodies have different angles with the positioning plane.

6. The differential planetary roller screw drive device according to claim 4, characterized in that The positioning rolling body is formed by processing a sphere. The two positioning planes are symmetric with respect to the sphere center plane, and the sphere center plane is a plane passing through its center of the sphere and parallel to the positioning plane.

7. The differential planetary roller screw drive device according to claim 6, characterized in that, The first positioning ring and the second positioning ring are symmetrically arranged along the sphere center plane of the positioning rolling body.

8. The differential planetary roller screw transmission according to any one of claims 1 to 7, characterized in that: A separator is further provided between adjacent positioning rolling bodies for positioning adjacent planetary rotation assemblies.

9. The differential planetary roller screw drive device according to claim 8, characterized in that, Both ends of the separator are respectively in contact with the first roller and the second roller.

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