Transmission mechanism

Abstract

The invention provides a transmission mechanism which is characterized by comprising an input element, a center shaft, at least one gear, a flange element and a connecting device, the input element is provided with an inner containing cavity, the inner containing cavity is provided with at least one eccentric containing part, the center shaft is provided with outer teeth, the at least one gear is provided with inner teeth, and the inner teeth are meshed with the outer teeth; the at least one gear is accommodated in the at least one eccentric accommodating part of the input element to be driven, the flange element is at least partially arranged on one side of the at least one gear, and the coupling device couples the flange element and the at least one gear; wherein one of the central shaft and the flange element is configured to be fixed, and the other one of the central shaft and the flange element is driven by at least one gear to rotate so as to output torque. According to the transmission mechanism, a small speed ratio is achieved, a large containing space is provided, meanwhile, the diameter of the pin of the planet carrier can be set to be large, and therefore enough transmission torque can be guaranteed.

Description

Technical Field

[0001] This application relates to a transmission mechanism, and more specifically to a transmission mechanism having a small speed ratio and a hollow structure. Background Technology

[0002] In some applications (such as joints in industrial robots, collaborative robots, and humanoid robots), speed reduction transmission mechanisms are used in small-sized applications, sometimes with an outer diameter of only about 100mm. Despite these size limitations, these mechanisms still need to achieve a certain transmission torque and high transmission efficiency, especially higher reverse drive efficiency. Summary of the Invention

[0003] According to one aspect of this application, a transmission mechanism is provided, characterized by comprising: an input element, a central shaft, at least one gear, a flange element, and a connecting device. The input element has a cavity with at least one eccentric receiving portion. The central shaft has external teeth, and the at least one gear has internal teeth configured to mesh with the external teeth of an output element. The at least one gear is received in the at least one eccentric receiving portion of the input element and is driven by the at least one eccentric receiving portion of the input element. The flange element is at least partially disposed on one side of the at least one gear, and the connecting device connects the flange element and the at least one gear. One of the central shaft and the flange element is configured to be stationary, and the other of the central shaft and the flange element is configured to rotate under the drive of the at least one gear to output torque.

[0004] According to one aspect of this application, the flange element comprises: a flange plate having a hollow structure, a central shaft passing through the hollow structure of the flange plate, and a coupling device connecting the flange plate to the at least one inner wheel.

[0005] According to one aspect of this application, the flange element further includes a housing portion disposed circumferentially around the input element.

[0006] According to one aspect of this application, the flange is fixedly connected to the housing portion.

[0007] According to one aspect of this application, the central shaft comprises a hollow accommodating cavity.

[0008] According to one aspect of this application, the flange element is configured to be stationary, and the central shaft is configured to rotate under the drive of the at least one gear; wherein the connecting device is configured to restrict the rotation of the at least one gear but allow the translation of the at least one gear.

[0009] According to one aspect of this application, the central shaft is configured to be fixed, and the flange element is configured to rotate under the drive of the at least one gear; wherein the connecting device is configured to convert the planetary motion of the at least one gear into the rotational motion of the flange element.

[0010] According to one aspect of this application, the connecting device includes a plurality of pins, and a plurality of pin fixing portions are provided on the flange, the plurality of pin fixing portions being distributed on the end face of the flange for connecting the plurality of pins; wherein, the at least one gear is provided with a plurality of pin holes for engaging with the plurality of pins to restrict the rotation of the at least one gear, wherein the diameter of each of the plurality of pin holes is larger than the outer diameter of each of the plurality of pins.

[0011] According to one aspect of this application, the connecting device comprises at least one connecting disc and an output connecting structure, wherein the at least one connecting disc connects the flange and the at least one gear through the output connecting structure; wherein the output connecting structure comprises a first set of output connecting structures and a second set of output connecting structures, the first set of output connecting structures being used to connect the at least one connecting disc to the flange element such that the at least one connecting disc can only move relative to the flange element in a first direction, and the second set of output connecting structures being used to connect the at least one gear to the at least one connecting disc such that the at least one gear can only move relative to the at least one connecting disc in a second direction, wherein the second direction is perpendicular to the first direction.

[0012] According to one aspect of this application, the at least one eccentric receiving portion includes a first eccentric portion and a second eccentric portion, wherein the eccentric directions of the first eccentric portion and the second eccentric portion differ by 180° in the circumferential rotation direction; the at least one gear includes a first gear and a second gear, the first gear being configured to be received in and driven by the first eccentric portion, and the second gear being configured to be received in and driven by the second eccentric portion; wherein the first gear has a first internal tooth, the second gear has a second internal tooth, and the first gear and the second gear are configured to mesh with the external teeth of the central shaft.

[0013] According to one aspect of this application, the internal teeth and the external teeth are involute teeth, circular arc teeth, cycloidal teeth or curved surface teeth, and the internal teeth and the external teeth mesh with each other through a difference in the number of teeth.

[0014] The transmission mechanism of this application achieves a small speed ratio output while significantly reducing eccentricity, which is beneficial for the arrangement of the planetary carrier. Furthermore, since the low tooth difference structure does not require the sun gear to be positioned in the center, there is sufficient space to design the output shaft or fixed shaft as a hollow structure, which can be used to accommodate cables.

[0015] Other features, advantages, and embodiments of this application may be set forth or become apparent upon consideration of the following detailed description, accompanying drawings, and claims. Furthermore, it should be understood that the above description and the following detailed description are exemplary and intended to provide further explanation, without limiting the scope of the claimed application. However, the detailed description and specific examples merely indicate preferred embodiments of this application. Various changes and modifications within the spirit and scope of this application will become apparent to those skilled in the art through these detailed descriptions. Attached Figure Description

[0016] These and other features and advantages of this application can be better understood by reading the following detailed description with reference to the accompanying drawings, in which the same reference numerals denote the same parts, wherein:

[0017] Figure 1A This is a radial sectional view of a transmission mechanism according to an embodiment of this application;

[0018] Figure 1B yes Figure 1A The transmission mechanism shown is a cross-sectional view along AA;

[0019] Figure 1C yes Figure 1A The transmission mechanism shown is a cross-sectional view along BB;

[0020] Figure 2A yes Figure 1A A 3D view of the input element shown;

[0021] Figure 2B yes Figure 2A The front view of the input element shown;

[0022] Figure 2C yes Figure 2B The input element shown is a cross-sectional view along CC;

[0023] Figure 3A yes Figure 1A A 3D view of the gear shown;

[0024] Figure 3B yes Figure 1A The diagram shows the connection of the first gear, the second gear, and the input element.

[0025] Figure 4A yes Figure 1A A 3D view of the output component shown;

[0026] Figure 4B yes Figure 4A The front view of the output element is shown;

[0027] Figure 4C yes Figure 4B The output element shown is a cross-sectional view along DD;

[0028] Figure 5 yes Figure 1A A perspective view of the fixed component shown, in which the housing and flange are integrally formed;

[0029] Figure 6 yes Figure 1A An exploded 3D view of the transmission mechanism shown.

[0030] Figure 7A This is a radial sectional view of the transmission mechanism according to the second embodiment of this application;

[0031] Figure 7B yes Figure 7A The transmission mechanism shown is a cross-sectional view along EE;

[0032] Figure 8A yes Figure 7A A 3D view of the connecting disk shown;

[0033] Figure 8B yes Figure 8A Alternative embodiments of the connecting disk shown;

[0034] Figure 9 yes Figure 7A The exploded perspective view of the conversion mechanism in the second embodiment of this application is shown.

[0035] Figure 10 This is a radial sectional view of the transmission mechanism according to the third embodiment of this application;

[0036] Figure 11 yes Figure 10 An exploded 3D view of the transmission mechanism shown.

[0037] Figure 12 This is a radial sectional view of the transmission mechanism according to the fourth embodiment of this application;

[0038] Figure 13 yes Figure 12 The exploded 3D view of the transmission mechanism is shown. Detailed Implementation

[0039] Various specific embodiments of this application will now be described with reference to the accompanying drawings, which form part of this specification. It should be understood that although directional terms such as "left," "right," "front," "rear," "up," "down," "inner," and "outer" are used in this application to describe various exemplary structural parts and elements, their use is merely for illustrative purposes and is based on the exemplary orientations shown in the drawings. Since the embodiments disclosed in this application can be arranged in different orientations, these directional terms are for illustrative purposes only and should not be considered limiting. In the following drawings, the same reference numerals are used for the same components.

[0040] The embodiments of this application provide a transmission mechanism that achieves a small speed ratio while having a large hollow storage space under the condition of limited external dimensions.

[0041] The first embodiment of this application is illustrated in [illustration]. Figure 1A , 1B 1C, 2A, 2B, 2C, 3A, 3B, 4A, 4B, 4C, 5, and 6. In this embodiment, a pin connection is used to limit the rotation of the gear.

[0042] like Figure 1A-1C As shown, the transmission mechanism 100 includes a fixed element, an input element 104, an output element 110, gears 106 and 108, pins 112, input element bearings 131 and 132, output element bearings 121 and 122, and gear bearings 141 and 142. The fixed element includes a housing 101, a flange 102, and an input end cover 116. The flange 102 and the input end cover 116 are fixedly connected together by several pins 112, which are evenly distributed circumferentially on the flange 102. The centerline of the circle containing the center points of all the pins 112 coincides with the centerline of the flange 102.

[0043] In the first embodiment of this application, the housing 101 and the flange 102 are manufactured as a single piece. However, those skilled in the art will understand that in some other embodiments, the housing 101 and the flange 102 may also be manufactured separately and then connected together by fixing or snap-fit ​​components.

[0044] In the first embodiment of this application, in order to achieve dynamic balance during transmission, the number of gears is set to two, namely the first gear 106 and the second gear 108. However, those skilled in the art will understand that in some other embodiments, the number of gears may be more than two, or only one gear may be provided in a transmission mechanism that does not require dynamic balance.

[0045] In the first embodiment of this application, the number of input element bearings 131, 132 is set to two, and the input element bearings 131, 132 are disposed between the input element 104 and the housing 101, so that the input element 104 is rotatably disposed inside the housing 101 via the input element bearings 131, 132. However, those skilled in the art will understand that in some other embodiments, the number of input element bearings may also be set to one or more than two.

[0046] In the first embodiment of this application, the number of output element bearings 121 and 122 is set to two. The output element bearings 121 and 122 are disposed between the output element 110 and the flange 102 and the input end cover 116, such that the output element 110 is rotatably disposed inside the flange 102 and the input end cover 116 via the output element bearings 121 and 122. However, those skilled in the art will understand that in some other embodiments, the number of output element bearings may also be one or more than two.

[0047] In the first embodiment of this application, the number of gear bearings 141, 142 is the same as the number of gears 106, 108, thus including a first gear bearing 141 and a second gear bearing 142. The first gear bearing 141 and the second gear bearing 142 are respectively disposed between the first gear 106, the second gear 108 and the input element 104, such that the first gear 106 and the second gear 108 are rotatably disposed relative to the input element 104 via the first gear bearing 141 and the second gear bearing 142, respectively.

[0048] Continue to refer to Figure 1A and combined Figure 2A-2C The input element 104 has a hollow structure and a through-cavity 154 extending in the axial direction. Two eccentrically oriented inner annular portions are arranged side-by-side in the axial direction from one side of the through-cavity 154. Each eccentrically oriented portion includes a first eccentric portion 151 and a second eccentric portion 152. The input element 104 has a central rotation axis O1, the first eccentric portion 151 has a central axis X1, and the second eccentric portion 152 has a central axis X2. The central axes X1 and X2 are parallel to the central rotation axis O1 and each has an eccentricity d relative to the central rotation axis O1. The central axes X1 and X2 are symmetrically eccentrically positioned relative to the central rotation axis O1, meaning they differ by 180° in the circumferential rotation direction. The first eccentric portion 151 and the second eccentric portion 152 have a first eccentric inner wall 202 and a second eccentric inner wall 204, respectively, and are configured to abut against the first gear bearing 141 and the second gear bearing 142, so that the first gear 106 and the second gear 108 are slidably disposed in the first eccentric portion 151 and the second eccentric portion 152 respectively through the first gear bearing 141 and the second gear bearing 142.

[0049] Continue to refer to Figure 1A and combined Figures 3A-3B In the first embodiment of this application, the first gear 106 is housed in the first eccentric portion 151 via the first gear bearing 141, and the second gear 108 is housed in the second eccentric portion 152 via the second gear bearing 142. Therefore, when the input element 104 rotates around the central rotation axis O1, it can drive the first gear 106 and the second gear 108 to move via the first eccentric portion 151 and the second eccentric portion 152 respectively.

[0050] As described above, in some other embodiments, in order to achieve dynamic balance during transmission, the number of gears can also be set to more than two, and correspondingly, the number of eccentric receiving portions of the input element 104 is consistent with the number of gears. In transmission mechanisms where dynamic balance is not required, only one gear can be provided, and therefore only one eccentric receiving portion can be provided in the input element 104.

[0051] Continue to refer to Figure 3A The first gear 106 and the second gear 108 have the same structure, which is a hollow annular structure with an internal gear ring. The internal gear ring has internal teeth 311 and 312 respectively. Several pin holes 314 are evenly arranged circumferentially between the internal teeth and the outer edge of the gear to accommodate the pins 112. Therefore, the annular pin hole structure of gears 106 and 108 for accommodating the pins 112 is also called a planetary carrier. Figure 1A As shown, the portion of the pin 112 passing through the pin hole 314 is fitted with a pin sleeve 114 to reduce the friction between the pin 112 and the pin hole 314 and prevent wear of the pin 112. As mentioned above, the flange 102 and the input end cover 116 are fixed together by several pins 112, and the gears 106 and 108 are arranged sequentially between the flange 102 and the input end cover 116 in the axial direction. The diameter of the pin hole 314 is larger than the outer diameter of the pin 112, so that when the gears 106 and 108 are driven in the eccentric receiving portions 151 and 152, the pin 112 can restrict the rotation of the gears 106 and 108, but allow the translation of the gears 106 and 108. Therefore, the pin 112 serves as a conversion mechanism in this embodiment to constrain the planetary motion of gears 106 and 108 to only translational motion. However, those skilled in the art will understand that in some other embodiments, the conversion mechanism is not limited to the form of the pin 112. As long as it can constrain the planetary motion of gears 106 and 108 to only translational motion, it can meet the requirements of this setting.

[0052] In the embodiments of this application, the number of pin holes is 10. In some other embodiments, the number of pin holes 314 can also be set to more than 2, as long as it can restrict the rotation of the gear.

[0053] Combination Figure 1B-1C The figures show cross-sectional views of the transmission mechanism 100 taken from the axial positions of the first eccentric portion 151 and the second eccentric portion 152. As shown in the diagram, the central axis X2 of the second eccentric portion 152 is located above the central rotation axis O1 of the input element 104, and the central axis X1 of the first eccentric portion 151 is located below the central rotation axis O1 of the input element 104. Since the pins 112 are evenly distributed around the flange 102, the center line of the circle containing the center points of all the pins 112 coincides with the center line of the flange 102. The center line of the flange 102 coincides with the central rotation axis O1 of the input element 104. Therefore, the center line of the circle containing the center points of all the pins 112 coincides with the central rotation axis O1 of the input element 104. Thus, in the diagram, the pins 112 are accommodated on the lower side of the pin hole 314 of the second gear 108, and also on the upper side of the pin hole 314 of the first gear 106, thereby showing the radial positional relationship between the first gear 106, the second gear 108, and the pins 112.

[0054] Continue to refer to Figure 1A and combined Figures 4A-4C The output element 110 has a hollow structure and a cavity 416 extending through it in the axial direction. A spline 414 is provided at one end of the cavity 416 for connecting to an output component (not shown). The output element 110 has an external gear ring with external teeth 412. The external teeth 412 are configured to mesh with the internal teeth 311, 312 of gears 106, 108, so that the translational motion of gears 106, 108 can be converted into the rotational motion of the output element 110 through tooth meshing. The number of teeth on the external teeth 412 of the output element 110 is less than the number of teeth on the internal teeth 311, 312 of gears 106, 108; therefore, during transmission, only a portion of the external teeth 412 of the output element 110 meshes with a portion of the internal teeth 311, 312 of gears 106, 108. In the embodiments of this application, the internal teeth 311, 312 and the external teeth 412 are involute teeth, circular arc teeth, cycloidal teeth or curved surface teeth. However, those skilled in the art will understand that in some other embodiments, the internal teeth 311, 312 and the external teeth 412 may also be other types of meshing structures, as long as they can transmit the translational motion of the gears 106, 108 and convert it into the rotational motion of the external teeth 412.

[0055] The output element 110 has a central rotation axis O2. In the first embodiment of this application, the central rotation axis O2 of the output element 110 coincides with the central rotation axis O1 of the input element 104.

[0056] Continue to refer to Figure 1A and combined with, for example Figure 5 As described above, the fixing element includes a housing 101 and a flange 102. In the first embodiment of this application, the housing 101 and the flange 102 are manufactured as a single piece. The housing 101 is a hollow structure having a housing cavity 502 for accommodating at least a portion of the input element 104 that rotates within it. The housing cavity 502 has a housing cavity wall 504 configured to abut against the input element bearings 131, 132, such that a portion of the input element 104 is rotatably disposed within the housing cavity 502 via the input element bearings 131, 132.

[0057] Flange 102 is also a hollow structure, located on one side of housing 101, and has an internal cavity 522 that allows output element 110 to pass through. The internal cavity 522 has a cavity wall 524 configured to abut against output element bearing 121, allowing output element 110 to be rotatably mounted inside flange 102 via output element bearing 121. A plurality of pin fixing portions 512 are evenly arranged circumferentially on the end face of flange 102 for connecting pins 112. The positions of the pin fixing portions 512 on flange 102 correspond to the positions of pin holes 314 on gears 106 and 108, and the number of pin fixing portions 512 is consistent with the number of pin holes 314 on gears 106 and 108. One end of the pin 112 is fixed to the flange 102 and passes through the pin holes 314 of the gears 106 and 108 in sequence, while the other end is fixed to a corresponding position on the input end cover 116, so that the pin 112 is fixedly connected to the flange 102, the housing 101, and the input end cover 116. The pin fixing part 512 can be formed by machining a hole in the flange 102 to allow the pin 112 to be fixedly inserted, or the pin 112 can be machined into the flange 102 as a whole to achieve the same effect as the pin fixing part 512.

[0058] Figure 6 yes Figure 1A The exploded 3D view of the transmission mechanism shown, combined with Figure 1AAs shown, in the first embodiment of this application, the housing 101, flange 102, and input end cover 116 together constitute the fixed element of the transmission mechanism 100. The housing 101 and flange 102 are manufactured as a single piece. The flange 102 is fixedly connected to the input end cover 116 by several pins 112. The center line of the circle containing the center points of all the pins 112 coincides with the center line of the housing 101, flange 102, and input end cover 116. The input element 104 is rotatably disposed in the inner cavity 502 of the housing 101 via input element bearings 131 and 132. Two identical first gears 106 and 108 are respectively housed in the first eccentric portion 151 and the second eccentric portion 152 of the input element 104 via first gear bearings 141 and second gear bearings 142, performing planetary motion. Several pins 112 pass through pin holes on the planetary carriers of the first gear 106 and the second gear 108, constraining the planetary motion of the gears 106 and 108 to only translational motion. The output element 110 passes through the internal gear ring cavity of the first gear 106 and the second gear 108, and is rotatably disposed in the internal cavity of the output element 110, flange 102 and input end cover 116 via output element bearings 121, 122. The external teeth 412 of the output element 110 mesh with the internal teeth 311, 312 of the gears 106, 108 in a manner with a difference in the number of teeth, thereby converting the translation of the gears 106, 108 into the rotation of the output element 110.

[0059] The second embodiment of this application is illustrated in Figure 1. Figure 7A , 7B Examples 8A, 8B, and 9 employ a connecting disc to restrict the rotation of the gears.

[0060] The second embodiment of this application works in a similar principle to the first embodiment, except that the structure of the conversion mechanism is different. The same structure will not be described again below.

[0061] like Figure 7A , 7B As shown in Figure 9, the conversion mechanism is a connecting disc, also known as a cross disc. In this embodiment, two gears 706 and 708 are provided in the eccentric receiving portion of the input element 104, and therefore two connecting discs are correspondingly provided, namely a first connecting disc 752 and a second connecting disc 754. The first connecting disc 752 and the second connecting disc 754 are respectively disposed in the axial direction between the first gear 706 and the flange 702, and between the second gear 708 and the input end cover 716. In order to accommodate the arrangement of the connecting discs, the structures of the two gears 706 and 708, the flange 702, and the input end cover 716 have been adjusted accordingly compared with the first embodiment of this application.

[0062] Since the two connecting discs 752 and 754 have the same cooperation and transmission principle with the two gears 706 and 708 and the flange 702 or the input end cover 716 respectively, the working principle of the connecting disc restricting the rotation of the gear is introduced below using the connection between the second connecting disc 754 and the second gear 708 and the input end cover 716 as an example.

[0063] like Figure 8A As shown, the second connecting plate 754 has a ring structure and a receiving cavity 812. Two pairs of blocking arms extend radially inward from the inner wall 814 of the receiving cavity 812, forming a first pair of blocking arms 802 and a second pair of blocking arms 804. The first pair of blocking arms 802 and the second pair of blocking arms 804 extend in mutually perpendicular directions. As an alternative embodiment, such as... Figure 8B As shown, by adjusting the outer diameter of the annular structure of the connecting disc 756 accordingly, it is also possible to extend radially outward from the outer wall 816 of the receiving cavity 812' by a certain length to form two pairs of blocking arms 802', 804', which are connected to... Figure 8A In the illustrated embodiment, the blocking arms 802 and 804 extend in the same direction.

[0064] To more clearly illustrate the working principle of the connection disk, Figure 9 The input and output components are omitted.

[0065] like Figure 9 As shown, to accommodate the blocking arm structure of the second connecting plate 754, the input end cover 716 protrudes axially a certain distance from one end face facing the second connecting plate 754, forming four first guide rail protrusions 722. The gap between the upper two first guide rail protrusions and the lower two first guide rail protrusions forms the first guide rail 723. The guiding direction of the first guide rail 723 is the same as the extension direction of the first pair of blocking arms 802, i.e., the first direction. The first guide rail 723 is configured to accommodate the sliding of the first pair of blocking arms 802 within the first guide rail 723. A roller 914 is provided between the first pair of blocking arms 802 and the first guide rail 723 to reduce the frictional force of the first pair of blocking arms 802 sliding within the first guide rail 723. Therefore, the first guide rail protrusions 722 and the first pair of blocking arms 802 constitute the first set of output connection structures connecting the input end cover 716 and the second connecting plate 754.

[0066] Similarly, the second gear 708 protrudes axially a certain distance from one end face facing the second connecting disk 754, forming four second guide rail protrusions 732. The gap between the two second guide rail protrusions on the left and the two second guide rail protrusions on the right forms a second guide rail 733. The guiding direction of the second guide rail 733 is the same as the extending direction of the second pair of blocking arms 804, i.e., the second direction, where the first direction and the second direction are perpendicular to each other. The second guide rail 733 is configured to accommodate the sliding of the second pair of blocking arms 804 within the second guide rail 733. A roller 916 is provided between the second pair of blocking arms 804 and the second guide rail 733 to reduce the frictional force of the second pair of blocking arms 804 sliding within the second guide rail 733. Therefore, the second guide rail protrusions 732 and the second pair of blocking arms 804 serve as a second set of output connection structures connecting the second gear 708 and the second connecting disk 754. The protrusion distance of the second guide rail protrusions 732 is less than the protrusion distance of the first guide rail protrusions 722.

[0067] Through the sliding engagement of the first pair of blocking arms 802 with the first guide rail 723, the second connecting plate 754 is limited to sliding only relative to the input end cover 716 in the first direction. Through the sliding engagement of the second pair of blocking arms 804 with the second guide rail 733, the second gear 708 is limited to sliding only relative to the second connecting plate 754 in the second direction. Through the combination of the above sliding limitations, the second gear 708 is limited to sliding only relative to the input end cover 716 in the direction combining the first and second directions, and cannot rotate relative to the input end cover 716.

[0068] Continue to refer to Figure 9 The first gear 706 and the second gear 708 are respectively provided with through-gear receiving grooves 952 and 954, and the number of receiving grooves on each gear corresponds to the number of first guide rail protrusions 722. The first guide rail protrusions 722 of the input end cover 716 can sequentially pass through the inner cavity of the second connecting plate 754, the receiving groove 954 of the second gear 708, the receiving groove 952 of the first gear 706, and the inner cavity of the first connecting plate 752, thereby contacting the flange 702. The axially extending end face of the first guide rail protrusion 722 is fixedly connected to the flange 702 by several bolts 912, thereby forming a fixed connection between the input end cover 716 and the flange 702. The opening size of the receiving grooves 952 and 954 on each gear is set to allow the first gear 706 and the second gear 708 to translate in a direction combining the first and second directions.

[0069] The first connecting plate 752 is connected to the first gear 706 and the flange 702 in the same manner as described above. Therefore, the first gear 706 is also limited to translation only relative to the flange 702 in the direction of the combination of the first direction and the second direction.

[0070] Those skilled in the art will understand that in a transmission mechanism that does not consider dynamic balance, only one gear can be provided, and correspondingly, only one connecting disc needs to be provided.

[0071] The following is combined with Figures 1A-9 The working process of the transmission mechanism in the first and second embodiments of this application is described below. When the transmission mechanism is used as a speed reduction mechanism, its power transmission relationship is roughly as follows:

[0072] The input element 104 is driven by an external drive device (such as a motor, not shown in the figure) to rotate around the central rotation axis O1. The input element 104 drives the first gear 106 and the second gear 108 to perform planetary motion through the first eccentric part 151 and the second eccentric part 152, respectively. Under the constraint of several pins 112 or connecting discs 752, 754, the first gear 106 and the second gear 108 can only translate under the drive of the first eccentric part 151 and the second eccentric part 152, and cannot rotate. During the translation process, the first gear 106 and the second gear 108 drive the output element 110 to rotate around the central rotation axis O2 through the meshing of the internal teeth 311, 312 and the external teeth 412, wherein the rotation axis O1 coincides with the rotation axis O2. The output element 110 is connected to an external component (not shown in the figure) through a spline 414 to output the rotational motion, thereby realizing the speed reduction transmission.

[0073] Those skilled in the art will understand that in some other embodiments, the transmission mechanism of this application is not limited to being used as a deceleration mechanism, and can also be used as a speed-increasing mechanism through a transmission path opposite to that described above.

[0074] The third embodiment of this application is illustrated in [illustration]. Figure 10 and 11 The third embodiment of this application has a similar structure to the first embodiment, and the same structure will not be described again below.

[0075] The first difference between the third embodiment and the first embodiment lies in the output component: in the first embodiment, the flange 102 remains fixed, and the output element 110 outputs rotation; in the third embodiment, the fixed shaft 1100 (corresponding to the output element 110 in the first embodiment, and its structure is consistent with the output element 110) remains fixed, and the flange 1002 outputs rotation. The second difference between the third embodiment and the first embodiment lies in the following: in the first embodiment, since the flange 102 and the housing 101 remain relatively fixed, the flange 102 and the housing 101 can be manufactured as a single piece; in the third embodiment, the flange 1002 needs to rotate relative to the housing 1001, therefore the flange 1002 and the housing 1001 are two independent components.

[0076] like Figure 10 As shown, the transmission mechanism 1000 also includes a flange bearing 1012. In the transmission mechanism 1000, the housing 1001 is a hollow structure, and at its other end relative to the input element 104, the housing 1001 has a flange cavity 1020. The flange cavity 1020 has an inner flange wall 1022, which is configured to abut against the flange bearing 1012, such that a portion of the flange 1002 is rotatably disposed within the flange cavity 1020 of the housing 1001 via the flange bearing 1012. The flange 1002 has a central rotation axis O3, which coincides with the central rotation axis O1 of the input element 104. Figure 10 In the third embodiment shown, since the flange 1002 is rotatable relative to the housing 1001, the flange 1002 is connected to the first gear 106 and the second gear 108 by several pins 112 without restricting the rotation of the first gear 106 and the second gear 108.

[0077] exist Figure 10 In the transmission mechanism 1000 shown, the fixed shaft 1100 remains fixed relative to the housing 1001. Specifically, in some applications, such as at the joints of a humanoid robot, the fixed shaft 1100 can be fixed relative to the housing 1001 by extending the fixed shaft 1100 to the adjacent joint position.

[0078] Figure 11 yes Figure 10 The exploded 3D view of the transmission mechanism 1000 shown, combined with... Figure 10As shown, in the third embodiment of this application, the housing 1001 and the fixed shaft 1100 are fixed in the transmission mechanism 1000. The flange 1002 is fixedly connected to the input end cover 116 by a plurality of pins 112. The center line of the circle containing the center points of all the pins 112 coincides with the center line of the housing 1001, the flange 1002 and the input end cover 116. The input element 104 is rotatably disposed in the inner cavity 502 of the housing 1001 by an input element bearing 132. Two identical first gears 106 and second gears 108 are respectively housed in the first eccentric portion 151 and the second eccentric portion 152 of the input element 104 by a first gear bearing 141 and a second gear bearing 142, and perform planetary motion. A plurality of pins 112 pass through the pin holes on the planetary carrier of the first gears 106 and the second gears 108, connecting the first gears 106 and the second gears 108 between the flange 1002 and the input end cover 116. The external teeth 412 of the fixed shaft 1100 mesh with the internal teeth 311, 312 of the gears 106, 108 in a manner with a difference in the number of teeth, so that the planetary motion of the gears 106, 108 can be converted into the rotation of the flange 1002 and the input end cover 116. The fixed shaft 1100 passes through the internal gear ring cavity of the first gear 106 and the second gear 108, and the flange 1002 and the input end cover 116 are rotatably mounted on the fixed shaft 1100 through the fixed shaft bearings 121, 122, respectively.

[0079] exist Figure 10-11 In the transmission mechanism 1000 shown, the planetary motion of gears 106 and 108 is converted into the rotational motion of flange 1002 via pin 112, that is, rotational torque is transmitted via pin 112. However, those skilled in the art will understand that in some other embodiments, a connecting disc or cross disc structure can be used to replace pin 112, thereby converting the planetary motion of gears 106 and 108 into the rotational motion of flange 1002. For a detailed implementation of replacing pin 112 with a connecting disc or cross disc structure, please refer to the second embodiment of this application, which will not be repeated here.

[0080] The fourth embodiment of this application is illustrated in [illustration]. Figure 12 and 13 The fourth embodiment of this application is similar in structure to the third embodiment. The main difference is that the fourth embodiment omits the shell 1001 compared to the third embodiment. The same structure will not be described again below.

[0081] In the transmission mechanism 1200 of the fourth embodiment, the input element 1204 has an input element inner cavity 1254, and the input element inner cavity 1254 has an input element inner wall 1208. As a radial support for the input element 1204, the input element bearing 1202 abuts against the input element inner wall 1208 and the input end cover 116 via a washer 1212, so that the input element 1204 is rotatably disposed on the outside of the input end cover 116 via the input element bearing 1202.

[0082] However, those skilled in the art will understand that in some other embodiments, the number of input element bearings can also be set to two. For example, the input element 1204 can be extended axially to wrap around the flange 1002 from the outside, and another input element bearing can be disposed between the input element 1204 and the flange 1002, so that the input element 1204 is rotatably disposed on the outside of the input end cover 116 and the flange 1002 respectively by the two input element bearings; or alternatively, only one input element bearing can be disposed between the input element 1204 and the flange 1002. In some other embodiments, the size of the input element 1204 can be adjusted accordingly according to the needs of the actual application, and the number of input element bearings can also be set to more than two.

[0083] Figure 13 yes Figure 12 The exploded 3D view of the transmission mechanism 1200 shown, combined with... Figure 12 As shown, in the fourth embodiment of this application, the fixed shaft 1100 is fixedly installed in the transmission mechanism 1200. The flange 1002 is fixedly connected to the input end cover 116 by a plurality of pins 112, and the center line of the circle containing the center points of all the pins 112 coincides with the center line of the flange 1002 and the input end cover 116. The input element 1204 is rotatably disposed on the outside of the input end cover 116 by the input element bearing 1202 and the washer 1212. Two identical first gears 106 and second gears 108 are respectively housed in the first eccentric portion 151 and the second eccentric portion 152 of the input element 1204 by the first gear bearing 141 and the second gear bearing 142, respectively, and perform planetary motion. A plurality of pins 112 pass through the pin holes on the planetary carrier of the first gear 106 and the second gear 108, connecting the first gear 106 and the second gear 108 between the flange 1002 and the input end cover 116. The external teeth 412 of the fixed shaft 1100 mesh with the internal teeth 311, 312 of the gears 106, 108 in a manner with a difference in the number of teeth, so that the planetary motion of the gears 106, 108 can be converted into the rotation of the flange 1002 and the input end cover 116. The fixed shaft 1100 passes through the internal gear ring cavity of the first gear 106 and the second gear 108, and the flange 1002 and the input end cover 116 are rotatably mounted on the fixed shaft 1100 through the fixed shaft bearings 121, 122, respectively.

[0084] exist Figure 12-13 In the transmission mechanism 1200 shown, the planetary motion of gears 106 and 108 is converted into the rotational motion of flange 1002 via pin 112, that is, rotational torque is transmitted via pin 112. However, those skilled in the art will understand that in some other embodiments, a connecting disc or a cross disc can be used to replace pin 112, thereby converting the planetary motion of gears 106 and 108 into the rotational motion of flange 1002. For a detailed implementation of replacing pin 112 with a connecting disc or a cross disc, please refer to the second embodiment of this application, which will not be repeated here.

[0085] Since the fourth embodiment omits the housing compared to the third embodiment, the radial dimension of the transmission mechanism 1200 is further reduced, thereby enabling it to better adapt to application scenarios with limited installation space for humanoid robots.

[0086] The following is combined with Figure 10-13 The working process of the transmission mechanism in the third and fourth embodiments of this application is described below. When the transmission mechanism is used as a speed reduction mechanism, its power transmission relationship is roughly as follows:

[0087] Input elements 104 and 1204 are driven by an external drive device (such as a motor, not shown in the figure) to rotate around the central rotation axis O1. Input elements 104 and 1204 drive the first gear 106 and the second gear 108 to perform eccentric motion through the first eccentric part 151 and the second eccentric part 152, respectively. Since the fixed shaft 1100 is fixed, i.e., the external gear 412 is fixed, the first gear 106 and the second gear 108 can achieve planetary motion by meshing the internal teeth 311 and 312 with the external teeth 412. This planetary motion is then converted into rotational motion of the flange 1002 around the central rotation axis O3 of the flange through the pin 112 or connecting discs 752 and 754. The flange 1002 can be connected to external components (not shown in the figure) to output the rotational motion, thereby achieving speed reduction transmission.

[0088] Those skilled in the art will understand that in some other embodiments, the transmission mechanism of this application is not limited to being used as a deceleration mechanism, and can also be used as a speed-increasing mechanism through a transmission path opposite to that described above.

[0089] In the above embodiments of this application, since the internal teeth 311, 312 mesh with the external teeth 412 through the difference in the number of teeth, the transmission ratio i based on the principle of transmission with a small tooth difference is calculated as follows:

[0090]

[0091] Where n2 represents the number of teeth on the internal gear ring, and n1 represents the number of teeth on the external gear ring of the output element or fixed shaft. In the embodiments of this application, the number of teeth n2 on the internal gear ring is 24, and the number of teeth n1 on the external gear ring of the output element or fixed shaft is 22, therefore the transmission ratio i can be calculated to be 11. Those skilled in the art will understand that in some other embodiments, the internal gear ring and the external gear ring of the output element or fixed shaft can also be designed with other different numbers of teeth to achieve the transmission ratio of the transmission mechanism required by the application scenario, especially a small transmission ratio.

[0092] The transmission mechanism of this application, by using internal teeth for the gears directly driven by the input element, can significantly reduce the pitch circle size of the internal teeth. This reduces the eccentricity in small-ratio transmission designs, facilitating the design of the planetary carrier. Therefore, the transmission mechanism of this application can easily be designed with small transmission ratios, such as 10 to 15. Generally, a higher transmission ratio results in lower transmission efficiency, and vice versa. For example, in humanoid robot applications, high transmission efficiency in both directions of the rotary joint deceleration device and effective use of the lifting torque sensor are required, typically necessitating a deceleration device ratio between 10 and 15. Therefore, the transmission mechanism of this application can meet the application scenarios of humanoid robots.

[0093] Furthermore, the transmission mechanism of this application, by employing an eccentric receiving portion on the inner cavity of the input element, houses the gear within the eccentric receiving portion for movement, and utilizes a transmission method where the internal teeth of the gear mesh with the external teeth of the output element or fixed shaft. This allows for a small speed ratio while providing a large hollow receiving space. In other words, despite limitations in external dimensions, the transmission mechanism of this application can still provide a large hollow receiving space while achieving higher transmission efficiency. Consequently, the cable of the drive mechanism (e.g., a motor) used in conjunction with the transmission mechanism of this application can be accommodated within this large hollow receiving space, allowing the transmission mechanism and drive mechanism to form a single, aesthetically pleasing machine.

[0094] Furthermore, by adopting the above structure, the transmission mechanism of this application achieves a small speed ratio and provides a large accommodating space, while allowing the diameter of the planetary carrier pin to be set to be larger, thereby ensuring sufficient transmission torque.

[0095] Specifically, due to the limited dimensions of the transmission mechanism and gears, the spatial arrangement of the planetary carrier is also subject to certain constraints. This is reflected in the fact that the size of the pin hole on the planetary carrier is affected by the pitch circle size of the gear's internal teeth; that is, the smaller the pitch circle size of the gear's internal teeth, the larger the pin hole size can be designed, and vice versa. Since the pitch circle size of the gear's internal teeth is positively correlated with the pitch circle size of the external teeth on the output element or fixed shaft, a larger pin hole size can be obtained by reducing the size of the pitch circle of the external teeth on the output element or fixed shaft, i.e., reducing the outer diameter of the output element or fixed shaft.

[0096] At the same time, according to the formula:

[0097] H = D + 2d + 2t

[0098] Where H represents the inner diameter of the pin hole, D represents the diameter of the pin, d represents the eccentricity, and t represents the thickness of the pin sleeve. Given a fixed pin sleeve thickness t and a limited inner diameter H of the pin hole, the eccentricity d should be as small as possible to obtain a larger pin diameter D.

[0099] Further based on the formula:

[0100] R = i × d,

[0101] Where R represents the radius of the external gear pitch circle, i represents the transmission ratio, and d represents the eccentricity mentioned above. Given a fixed transmission ratio i, to obtain a smaller eccentricity d, the radius R of the external gear pitch circle should be as small as possible.

[0102] Based on the above conditions, it can be concluded that as long as the radius R of the pitch circle of the external tooth can be reduced, that is, the outer diameter of the output element or the fixed shaft can be reduced, a larger pin hole size H can be designed, and thus a larger pin diameter D can be designed.

[0103] This application employs an eccentric receiving portion on the inner cavity of the input element, housing the gear within the eccentric receiving portion for movement, and using a transmission method where the internal teeth of the gear mesh with the external teeth of the output element or fixed shaft. This allows for a significant reduction in the pitch circle radius R of the external teeth of the output element or fixed shaft, thereby enabling a larger pin hole. This allows for a larger pin diameter D, resulting in better transmission torque.

[0104] Furthermore, as described above, in the first and second embodiments of this application, the output element is small in size, which makes it easier to reverse drive the output element. That is, the output element is more sensitive to reverse applied rotational torque, resulting in higher reverse drive efficiency. Reverse drive occurs, for example, when encountering an obstacle. When the output element is more sensitive to reverse rotational torque, it may even be possible to trigger the reverse rotation of the output element due to an obstacle without the need for a torque sensor.

[0105] The transmission mechanism of this application is simple to process and does not require a complex structural design like cycloidal gears or harmonic gears. Therefore, the transmission mechanism of this application can have a lower processing cost.

[0106] Although this disclosure has been described in conjunction with examples of the embodiments outlined above, various alternatives, modifications, variations, improvements, and / or substantially equivalents, whether known or currently or soon to be foreseen, will likely be apparent to those skilled in the art. Furthermore, the technical effects and / or technical problems described herein are exemplary and not limiting; therefore, the disclosures herein may be used to solve other technical problems and have other technical effects and / or can solve other technical problems. Thus, the examples of embodiments of this disclosure as set forth above are intended to be illustrative and not limiting. Various changes may be made without departing from the spirit or scope of this disclosure. Therefore, this disclosure is intended to include all known or previously developed alternatives, modifications, variations, improvements, and / or substantially equivalents.

Claims

1. A transmission mechanism, characterized in that... include: An input element (104, 1204) has a content cavity (154, 1254) and the content cavity (154, 1254) is provided with at least one eccentric receiving portion (151, 152). A central shaft (110, 1100) is provided with external teeth (412); At least one gear (106, 108) having internal teeth (311, 312) configured to mesh with the external teeth (412) of the output element (110), the at least one gear (106, 108) being housed in at least one eccentric receiving portion (151, 152) of the input element (104) and thus being driven by the at least one eccentric receiving portion (151, 152) of the input element (104); A flange element, said flange element being disposed at least partially on one side of the at least one gear (106, 108); as well as A connecting device that connects the flange element and the at least one gear (106, 108); In this configuration, one of the central shaft (110, 1100) and the flange element is configured to remain stationary, while the other of the central shaft (110, 1100) and the flange element is configured to rotate under the drive of the at least one gear (106, 108) to output torque.

2. The transmission mechanism according to claim 1, characterized in that... The flange element includes: A flange (102, 1002) comprising a hollow structure, a central shaft (110, 1100) passing through the hollow structure of the flange (102, 1002), and a connecting device connecting the flange (102, 1002) to at least one inner wheel (106, 108).

3. The transmission mechanism according to claim 2, characterized in that... The flange element also includes: The housing portions (101, 1001) are arranged circumferentially around the input element (104).

4. The transmission mechanism according to claim 3, characterized in that: The flanges (102, 1002) are fixedly connected to the housing parts (101, 1001).

5. The transmission mechanism according to claim 1, characterized in that: The central axis (110, 1100) includes a hollow receiving cavity (416).

6. The transmission mechanism according to claim 1, characterized in that: The flange element is configured to remain stationary, and the central shaft (110, 1100) is configured to rotate under the drive of the at least one gear (106, 108). The connecting device is configured to restrict the rotation of the at least one gear (106, 108) but allow the translation of the at least one gear (106, 108).

7. The transmission mechanism according to claim 1, characterized in that: The central shaft (110, 1100) is configured to remain stationary, and the flange element is configured to rotate under the drive of the at least one gear (106, 108). The connecting device is configured to convert the planetary motion of the at least one gear (106, 108) into the rotational motion of the flange element.

8. The transmission mechanism according to claim 2, characterized in that: The connecting device includes several pins (112), and several pin fixing parts (512) are provided on the flange (102, 1002). The several pin fixing parts (512) are distributed on the end face of the flange (102, 1002) and are used to connect the several pins (112). The at least one gear (106, 108) is provided with a plurality of pin holes (314) for cooperating with the plurality of pins (112) to restrict the rotation of the at least one gear (106, 108), wherein the diameter of each of the plurality of pin holes (314) is larger than the outer diameter of each of the plurality of pins (112).

9. The transmission mechanism according to claim 1, characterized in that: The connecting device includes at least one connecting plate (752, 754) and an output connecting structure, wherein the at least one connecting plate (752, 754) connects the flange (102, 1002) and the at least one gear (706, 708) through the output connecting structure. The output connection structure includes a first set of output connection structures (802, 722) and a second set of output connection structures (804, 732). The first set of output connection structures (802, 722) is used to connect the at least one connecting disc to the flange element, such that the at least one connecting disc (752, 754) can only move relative to the flange element in a first direction. The second set of output connection structures (804, 732) is used to connect the at least one gear (706, 708) to the at least one connecting disc (752, 754), such that the at least one gear (706, 708) can only move relative to the at least one connecting disc (752, 754) in a second direction, wherein the second direction is perpendicular to the first direction.

10. The transmission mechanism according to claim 1, characterized in that: The at least one eccentric receiving portion (151, 152) includes a first eccentric portion (151) and a second eccentric portion (152), wherein the eccentric directions of the first eccentric portion (151) and the second eccentric portion (152) differ by 180° in the circumferential rotation direction. The at least one gear includes a first gear (106) and a second gear (108), the first gear (106) being configured to be received in and driven by the first eccentric portion (151), and the second gear (108) being configured to be received in and driven by the second eccentric portion (152). The first gear (106) has a first internal tooth (311), the second gear (108) has a second internal tooth (312), and the first gear (106) and the second gear (108) are configured to mesh with the external tooth (412) of the central shaft (110).

11. The transmission mechanism according to claim 1, characterized in that: The internal teeth (311, 312) and the external teeth (412) are involute teeth, circular arc teeth, cycloidal teeth or curved surface teeth, and the internal teeth (311, 312) and the external teeth (412) mesh with each other through the difference in the number of teeth.

Images