Drive structure and robotic arm

Abstract

The present invention relates to a drive structure and a robotic arm. The drive structure comprises a housing, a plurality of output shafts, and a plurality of drive assemblies. The plurality of output shafts are concentrically arranged and are all rotatably arranged relative to the housing. The plurality of drive assemblies are circumferentially arranged with the output shaft as the center, each drive assembly corresponds to one output shaft, and can drive the corresponding output shaft to rotate. Each drive assembly comprises a driving member, a first gear set, a transmission shaft, and a second gear set. The driving member is fixed to the housing, and the output shaft of the driving member is in transmission connection with the first gear set, and the two ends of the transmission shaft are respectively in transmission connection with the first gear set and the second gear set, and the second gear set is in transmission connection with the corresponding output shaft. By arranging the transmission shaft between the output shafts of the driving member, on the one hand, the radius of the large gear is reduced and the strength of the gear is increased; on the other hand, the span between the shafts is greatly reduced, thereby effectively increasing the transmission accuracy.

Description

Technical Field

[0001] The present invention relates to the technical field related to robot transmission, and in particular to a drive structure and a robotic arm for use in extreme environments. Background Art

[0002] In extreme environments such as high radiation and high pollution, the motors, sensors and other electronic components of ordinary joint-driven robots cannot work properly. Therefore, the driving device of the driving robot needs to be placed outside the protective measures to ensure that the driving device is isolated from the extreme environment;

[0003] Currently, there are some mechanical transmission manipulators, whose drive structures are all set at the base end of the manipulator. The power is transmitted to the actuator of the manipulator through the mechanical transmission mechanism, and the multi-degree-of-freedom movement of the manipulator can be achieved. Thus, the drive device is externalized while ensuring the transmission accuracy, so that the manipulator can be used in extreme environments.

[0004] However, the driving force of this type of robotic arm needs to be transmitted from the base end to the execution end through mechanical transmission, so there are high requirements for the torque output by the base end. In order to meet the torque requirements, the existing drive structure usually requires the gear set between the drive member and the output shaft to have a larger tooth ratio, that is, one of the gears has a larger diameter, which results in a larger span between the drive member and the output shaft and lower gear meshing accuracy. Summary of the Invention

[0005] Based on this, it is necessary to provide a driving structure and a robotic arm suitable for a base-driven robotic arm with high gear meshing accuracy in order to address the problem of low gear meshing accuracy in the driving structure of the base-driven robotic arm.

[0006] The present invention first provides a driving structure, including a housing, multiple output shafts and multiple groups of drive assemblies; the multiple output shafts are concentrically arranged and are all rotatable relative to the housing; the multiple groups of drive assemblies are circumferentially arranged with the output shaft as the center, each group of drive assemblies corresponds to one output shaft, and can drive the corresponding output shaft to rotate; each drive assembly includes a driving member, a first gear group, a transmission shaft and a second gear group, the driving member is fixed to the housing, and the output shaft of the driving member is transmission-connected to the first gear group, the two ends of the transmission shaft are respectively transmission-connected to the first gear group and the second gear group, and the second gear group is transmission-connected to the corresponding output shaft; along the radial direction of the output shaft, the output shaft, the corresponding transmission shaft and the corresponding output shaft of the driving member are arranged in sequence from inside to outside.

[0007] The above-mentioned drive structure uses a two-stage gear transmission instead of the single-stage gear transmission in the prior art by setting a transmission shaft between the output shaft of the driving member. On the one hand, it reduces the radius of the large gear, thereby reducing the gear cost and increasing the strength of the gear; on the other hand, it greatly reduces the span between the shafts, thereby effectively reducing the possibility of poor meshing between gears, increasing the meshing accuracy of the gears between the shafts, and thus increasing the transmission accuracy.

[0008] In one embodiment, the first gear sets are located in the same plane along the radial direction of the output shaft.

[0009] It can be understood that the matching output shaft, the corresponding transmission shaft and the corresponding output shaft of the driving member are arranged in sequence from the inside to the outside. The first gear set can be regarded as radially radiating with the axis of the output shaft as the center, so as to make full use of the internal space of the box to reduce the volume of the driving mechanism.

[0010] In one embodiment, the first gear set includes a first gear and a second gear that mesh with each other, the first gear is fixed to the output shaft of the driving member, and the second gear is fixed to the transmission shaft.

[0011] In one embodiment, the distance between the end face of the output shaft close to the driving member and the plane where the driving member is located gradually increases from the inside to the outside of each output shaft, and each second gear set corresponds to the part of the output shaft protruding from the other output shafts.

[0012] It can be understood that it can be ensured that when the second gear set is in transmission connection with the corresponding output shaft, it will not interfere with other drive components or other output shafts.

[0013] In one embodiment, the drive structure also includes a plurality of support members fixed to the box body, and the support members correspond one-to-one to the drive components; the second gear set includes a third gear and a fourth gear that are meshed with each other, the third gear is fixed to the transmission shaft, the fourth gear and the transmission shaft are both rotatably connected to the corresponding support members, and the fourth gear is fixedly connected to the corresponding output shaft.

[0014] It can be understood that the third gear and the fourth gear share a reference surface, namely the support member, which can effectively avoid the accumulation of tolerances; in addition, during the processing process, it is only necessary to ensure the center distance accuracy of the two holes corresponding to the drive shaft and the fourth gear on the support plate to ensure the meshing accuracy between the third gear and the fourth gear, thereby making the drive structure connection reliable and compact.

[0015] In one embodiment, the housing includes a first housing and a second housing, the first gear set is arranged in the first housing, the second gear set is arranged in the second housing, and the outer peripheral surface diameter of the second housing gradually decreases along the axial direction of the output shaft, from the direction close to the driving member to the direction away from the driving member.

[0016] It can be understood that the transmission shaft passes through the second housing to the first housing, thereby having two support points with a small distance between them, including the support member, to increase the stability of the transmission shaft during rotation.

[0017] In one embodiment, a plurality of step surfaces with gradually decreasing inner diameters are formed in the housing along the axial direction of the output shaft, from a direction close to the driving member to a direction away from the driving member, and the step surfaces correspond one-to-one to the support members. One end of the support member is fixedly connected to the corresponding step surface, and the other end is rotatably connected to the corresponding fourth gear through a bearing.

[0018] It can be understood that the provision of the step surface can also ensure the horizontality of the support member, and the step surface can also play a positioning role for the corresponding support member to facilitate the loading and unloading of the support member.

[0019] In one embodiment, the drive components are equidistantly arranged around the axis of the output shaft.

[0020] It is understandable that the circumferentially equidistant arrangement with the axis of the output shaft as the center can ensure that the internal space of the box is utilized as much as possible without interfering with each other, so as to reduce the required volume of the box 10.

[0021] In one embodiment, the output shaft partially extends out of the housing, and the end of the output shaft located outside the housing is fixedly connected to a fifth gear.

[0022] A second aspect of the present invention provides a robotic arm comprising the aforementioned drive structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the following briefly introduces the drawings required for use in the embodiments or the conventional technology descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 It is a schematic diagram of the three-dimensional structure of the present invention;

[0025] Figure 2 for Figure 1Schematic diagram of the cross-sectional structure in the center-front view direction;

[0026] Figure 3 for Figure 2 Schematic diagram of the cross-sectional structure at AA in the middle;

[0027] Figure 4 for Figure 2 Schematic diagram of the cross-sectional structure at the middle BB;

[0028] Figure 5 for Figure 2 An enlarged structural diagram of the connection position between the fourth gear and the support member;

[0029] Figure numerals: 10, housing; 11, first housing; 12, second housing; 121, step surface; 13, partition; 20, output shaft; 21, fifth gear; 30, drive assembly; 31, drive member; 32, first gear set; 321, first gear; 322, second gear; 33, transmission shaft; 34, second gear set; 341, third gear; 342, fourth gear; 40, support member; 41, bearing; 42, retaining ring; 43, pressure cover. DETAILED DESCRIPTION

[0030] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

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

[0032] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0033] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it can mean that the first feature is directly in contact with the second feature, or that the first feature and the second feature are in contact indirectly through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it can mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature.

[0034] The first feature being “below”, “beneath”, and “below” the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the horizontal height of the first feature is smaller than that of the second feature.

[0035] 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 art 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 relevant listed items.

[0036] See also Figure 1 and Figure 2 As shown, the present application first provides a driving structure, including a housing 10, multiple output shafts 20 and multiple groups of drive assemblies 30; the multiple output shafts 20 are concentrically arranged and are all rotatably arranged relative to the housing 10; the multiple groups of drive assemblies 30 are circumferentially arranged with the output shaft 20 as the center, each group of drive assemblies 30 corresponds to an output shaft 20, and can drive the corresponding output shaft 20 to rotate; each drive assembly 30 includes a driving member 31, a first gear group 32, a transmission shaft 33 and a second gear group 34, the driving member 31 is fixed to the housing 10, and the output shaft of the driving member 31 is transmission-connected with the first gear group 32, the two ends of the transmission shaft 33 are transmission-connected with the first gear group 32 and the second gear group 34 respectively, and the second gear group 34 is transmission-connected with the corresponding output shaft 20; along the radial direction of the output shaft 20, the output shaft 20, the corresponding transmission shaft 33 and the output shaft of the corresponding driving member 31 are arranged in sequence from inside to outside.

[0037] By arranging a transmission shaft 33 between the output shaft of the driving member 31 and the output shaft 20, and connecting the output shaft of the driving member 31 and the transmission shaft 33 through the first gear set 32 ​​and connecting the transmission shaft 33 and the output shaft 20 through the second gear set 34, a two-stage gear transmission is used instead of the single-stage gear transmission in the prior art;

[0038] The use of two-stage gear transmission, on the one hand, reduces the gear ratio required for each stage of gear transmission, and the radius of the large gear in each stage of gear transmission is greatly reduced compared with the radius of the large gear in the single-stage gear transmission.

[0039] This reduces the gear radius, reducing gear costs while increasing gear strength;

[0040] On the other hand, the two-stage gear transmission also greatly reduces the span between the output shaft of the driving member 31 and the transmission shaft 33, and between the transmission shaft 33 and the output shaft 20, compared with the span between the active shaft and the driven shaft in the single-stage gear transmission, thereby effectively reducing the possibility of poor meshing between gears, increasing the meshing accuracy of the gears between shafts, and thereby increasing the transmission accuracy.

[0041] The span in this article refers to the axis distance between the driving shaft and the driven shaft.

[0042] In addition, multiple sets of drive assemblies 30 are provided, each corresponding to the output shaft 20. The output shaft 20, the corresponding transmission shaft 33, and the output shaft of the corresponding driving member 31 are arranged in sequence from the inside to the outside along the radial direction of the output shaft 20.

[0043] On the one hand, the components in each set of drive assemblies 30 are arranged in the radial direction, so that the multiple sets of drive assemblies 30 are radially distributed with the axis of the output shaft 20 as the center, thereby making full use of the internal space of the housing 10 and reducing the overall volume of the drive mechanism;

[0044] On the other hand, the output shaft 20, the transmission shaft 33 and the output shaft of the driving member 31 are in the same straight line. When the distance between the output shaft 20 and the output shaft of the driving member 31 is constant, the span between the output shaft of the driving member 31 and the transmission shaft 33, as well as the span between the transmission shaft 33 and the output shaft 20 can be minimized, thereby reducing the above two spans as much as possible to further increase the transmission accuracy.

[0045] Please refer to Figure 1 and Figure 2 As shown, in some embodiments, the driving structure further includes a central driving member, which is fixed to the housing 10 , and a driving shaft of the central driving member is connected to an output shaft 20 located in the center.

[0046] Please refer to Figure 2 and Figure 3 As shown, in some embodiments, each first gear set 32 ​​is located in the same plane along the radial direction of the output shaft 20;

[0047] The matching output shaft 20, the corresponding transmission shaft 33 and the corresponding output shaft of the driving member 31 are arranged from the inside to the outside along the radial direction of the output shaft 20, so that the first gear set 32 ​​is radially radiated with the axis of the output shaft 20 as the center. In this way, the internal space of the box 10 can be utilized as much as possible to reduce the volume of the driving mechanism while ensuring that the various first gear sets 32 do not interfere with each other.

[0048] Please refer to Figure 2 As shown, in some embodiments, the first gear set 32 ​​includes a first gear 321 and a second gear 322 that mesh with each other, the first gear 321 is fixed to the output shaft of the driving member 31, and the second gear 322 is fixed to the transmission shaft 33;

[0049] The first gear 321 is key-connected to the output shaft of the driving member 31 , and the second gear 322 is spline-connected to the corresponding transmission shaft 33 . The spline is an involute spline to facilitate the installation of the second gear 322 .

[0050] Please refer to Figure 2 As shown, in some embodiments, the distance between the end surface of the output shaft 20 close to the driving member 31 and the plane where the driving member 31 is located gradually increases from the inside to the outside of each output shaft 20, and each second gear set 34 corresponds to a portion of the output shaft 20 that protrudes from the other output shafts 20;

[0051] It can be understood that by setting the concentrically arranged output shafts 20 to be conical, and at the same time installing each second gear set 34 at different heights along the axial direction of the output shaft 20 and corresponding to the portion of each output shaft 20 protruding from the other output shafts 20;

[0052] It can ensure that when the second gear set 34 is in transmission connection with the corresponding output shaft 20 , it will not interfere with other drive components 30 or other output shafts 20 .

[0053] Please refer to Figure 2 and Figure 4 As shown, in some embodiments, the drive structure further includes a plurality of support members 40 fixed to the housing 10, and the support members 40 correspond one to one with the drive assembly 30; the second gear set 34 includes a third gear 341 and a fourth gear 342 that mesh with each other, the third gear 341 is fixed to the transmission shaft 33, the fourth gear 342 and the transmission shaft 33 are both rotatably connected to the corresponding support member 40, and the fourth gear 342 is fixedly connected to the corresponding output shaft 20;

[0054] Since the third gear 341 is fixed to the transmission shaft 33, and the transmission shaft 33 and the fourth gear 342 are both mounted on the support member 40, the third gear 341 and the fourth gear 342 share a common reference surface, namely the support member 40. This effectively avoids tolerance accumulation compared to when the third gear 341 and the fourth gear 342 are mounted on different reference surfaces.

[0055] It can be understood that during the processing, it is only necessary to ensure the center distance accuracy of the two holes corresponding to the transmission shaft 33 and the fourth gear 342 on the support member 40 to ensure the meshing accuracy between the third gear 341 and the fourth gear 342, so that the drive structure connection is reliable and compact.

[0056] Please refer to Figure 5 As shown, in some embodiments, the fourth gear 342 is connected to the support member 40 through a bearing 41, the inner ring of the bearing 41 is fixed to the outer circumferential surface of the fourth gear 342 through a retaining ring 42, and the outer ring of the bearing 41 is fixed to the support member 40 through a pressure cover 43. The pressure cover 43 can be fixed to the support member 40 by screws to facilitate loading and unloading.

[0057] Please refer to Figure 2 As shown, in some embodiments, the housing 10 includes a first housing 11 and a second housing 12, the first gear set 32 ​​is disposed in the first housing 11, the second gear set 34 is disposed in the second housing 12, and the outer peripheral surface diameter of the second housing 12 gradually decreases from a direction close to the driving member 31 to a direction away from the driving member 31 along the axial direction of the output shaft 20;

[0058] The housing 10 further includes a partition 13. The first housing 11, the partition 13, and the second housing 12 are fixedly connected in sequence. The first housing 11 and the second housing 12 have openings on one side close to the partition 13. The first gear set 32 ​​and the second gear set 34 are respectively disposed in the corresponding openings. The partition 13 can be fixedly connected to the first housing 11 and the second housing 12 to close the corresponding openings. The transmission shaft 33 is rotatably connected to the partition 13.

[0059] As a result, the transmission shaft 33 is supported by the partition 13 and the support member 40 respectively, and the distance between the two support points is relatively short, which reduces or even avoids radial vibration of the transmission shaft 33 during rotation, and further increases the stability of the transmission shaft 33 during rotation.

[0060] It should be noted that in the present application, the partition 13 is fixed to the sealed box for extreme environments, so that the first box 11 is located in the external environment, and the second box 12 is located in the extreme environment inside the sealed box. The first box 11 and the partition 13, the partition 13 and the second box 12, and the second box 12 and the outermost output shaft 20 are all sealed with each other to prevent the electronic components in the box 10 from being affected by the extreme environment and malfunctioning, thereby meeting the use requirements in extreme environments.

[0061] The sealing here can be one or more of mechanical sealing, sealing element sealing or other commonly used sealing methods, and this application does not make any specific limitations here.

[0062] Please refer to Figure 2 and Figure 4As shown, in some embodiments, a plurality of stepped surfaces 121 with gradually decreasing inner diameters are formed in the housing 10 along the axial direction of the output shaft 20, from a direction close to the driving member 31 to a direction away from the driving member 31. The stepped surfaces 121 correspond one-to-one with the support members 40. One end of the support member 40 is fixedly connected to the corresponding stepped surface 121, and the other end is rotatably connected to the corresponding fourth gear 342 via a bearing.

[0063] The support member 40 can be understood as extending radially from the output shaft 20 to the side wall of the housing 10 and being fixed to the stepped surface 121. By distributing the support members 40 circumferentially, it is avoided that the support members 40 close to the driving member 31 occupy too much space, thereby affecting the arrangement of other driving components 30.

[0064] In addition, the setting of the step surface 121 can also ensure the horizontality of the support member 40, and since the support member 40 passes through the opening of the second box body 12 and is installed to the corresponding position in the second box body 12 along the output shaft 20, the corresponding step surface 121 can block the support member 40 and limit its further movement. Therefore, the step surface 121 can also play a positioning role to facilitate the loading and unloading of the support member 40.

[0065] Please refer to Figure 2 、 Figure 3 as well as Figure 4 As shown, in some embodiments, the drive assembly 30 is equidistantly arranged circumferentially with the axis of the output shaft 20 as the center;

[0066] Under the premise of ensuring that the various driving components 30 do not interfere with each other, the internal space of the box 10 is utilized as much as possible to reduce the required volume of the box 10; preferably, six groups of driving components 30 are provided.

[0067] Please refer to Figure 1 As shown, in some embodiments, the output shaft 20 partially extends outside the housing 10.

[0068] The end of the output shaft 20 located outside the housing 10 is fixedly connected to a fifth gear 21;

[0069] Among them, the distance between the end face of the output shaft 20 away from the driving member 31 and the plane where the driving member 31 is located gradually decreases in the order from the inside to the outside of each output shaft 20. The fifth gear 21 is fixed to the side of each output shaft 20 away from the driving member 31 and protrudes from the part of other output shafts 20.

[0070] A second aspect of the present invention provides a robotic arm comprising the aforementioned drive structure.

[0071] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0072] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, all of which fall within the scope of protection of the present application. Therefore, the scope of patent protection for the present application shall be determined by the appended claims.

Claims

1. A driving structure, characterized in that: It comprises a housing (10), a plurality of output shafts (20), and a plurality of drive components (30); The plurality of output shafts (20) are concentrically arranged and are all rotatably arranged relative to the box body (10); A plurality of groups of the drive components (30) are circumferentially arranged with the output shaft (20) as the center, and each group of the drive components (30) corresponds to one output shaft (20) and is capable of driving the corresponding output shaft (20) to rotate; Each of the driving components (30) includes a driving member (31), a first gear group (32), a transmission shaft (33) and a second gear group (34); the driving member (31) is fixed to the housing (10), and the output shaft of the driving member (31) is in transmission connection with the first gear group (32); both ends of the transmission shaft (33) are in transmission connection with the first gear group (32) and the second gear group (34) respectively; and the second gear group (34) is in transmission connection with the corresponding output shaft (20); Along the radial direction of the output shaft (20), the output shaft (20), the corresponding transmission shaft (33), and the corresponding output shaft of the driving member (31) are arranged in sequence from the inside to the outside; The driving structure further comprises a plurality of support members (40) fixed to the box body (10), wherein the support members (40) correspond one-to-one to the driving components (30); The second gear set (34) includes a third gear (341) and a fourth gear (342) meshing with each other, the third gear (341) being fixed to the transmission shaft (33), the fourth gear (342) and the transmission shaft (33) being rotationally connected to the corresponding support member (40), and the fourth gear (342) being fixedly connected to the corresponding output shaft (20); A plurality of stepped surfaces (121) with gradually decreasing inner diameters are formed in the housing (10) along the axial direction of the output shaft (20), from a direction close to the driving member (31) to a direction away from the driving member (31), wherein the stepped surfaces (121) correspond one-to-one with the supporting members (40), and one end of the supporting member (40) is fixedly connected to the corresponding stepped surface (121), and the other end is rotatably connected to the corresponding fourth gear (342) via a bearing; The box body (10) comprises a first box body (11), a second box body (12) and a partition (13), and the transmission shaft (33) is rotatably connected to the partition (13).

2. The driving structure according to claim 1, characterized in that: Each of the first gear sets (32) is located in the same plane along the radial direction of the output shaft (20).

3. The driving structure according to claim 2, characterized in that: The first gear set (32) comprises a first gear (321) and a second gear (322) meshing with each other, the first gear (321) being fixed to the output shaft of the driving member (31), and the second gear (322) being fixed to the transmission shaft (33).

4. The driving structure according to claim 1, characterized in that: The distance between the end surface of the output shaft (20) close to the driving member (31) and the plane where the driving member (31) is located gradually increases in order from the inside to the outside of each output shaft (20), and each second gear set (34) corresponds to a portion of the output shaft (20) protruding from the other output shafts (20).

5. The driving structure according to claim 1, characterized in that: The first gear set (32) is arranged in the first housing (11), and the second gear set (34) is arranged in the second housing (12). The diameter of the outer peripheral surface of the second housing (12) gradually decreases from a direction close to the driving member (31) to a direction away from the driving member (31) along the axial direction of the output shaft (20).

6. The driving structure according to claim 1, characterized in that: The drive components (30) are equidistantly arranged in the circumferential direction with the axis of the output shaft (20) as the center.

7. The driving structure according to claim 1, characterized in that: The output shaft (20) partially extends outside the housing (10), and the end of the output shaft (20) located outside the housing (10) is fixedly connected to a fifth gear (21).

8. A robotic arm, characterized in that: The drive structure comprises the drive structure as described in any one of claims 1 to 7.

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