Power unit assembly, joint module and legged robot

Abstract

This application provides a power unit assembly, a joint module, and a legged robot. The power unit assembly includes a motor, a high-speed planetary reducer, and a low-speed planetary reducer; wherein the motor, high-speed planetary reducer, and low-speed planetary reducer are arranged sequentially along the motor's axis; the high-speed planetary reducer is driven by the motor; the low-speed planetary reducer is driven by the high-speed planetary reducer; along the motor's axis, the high-speed planetary reducer is partially embedded within the low-speed planetary reducer; the motor is fixed relative to a first joint component; the output end of the low-speed planetary reducer is fixed relative to a second joint component. In the above technical solution, by employing axial engagement between the high-speed and low-speed planetary reducers, the two are coupled, thereby reducing the axial dimension of the power unit assembly, improving its compactness, and decreasing its volume.

Description

Technical Field

[0001] This application relates to the field of robotics technology, and more specifically, to a power unit assembly, a joint module, and a legged robot. Background Technology

[0002] Due to advancements in battery and motor technologies in recent years, electric drive solutions have gradually become the mainstream for legged robots.

[0003] The power unit, as the robot's actuator, directly affects the robot's performance and cost due to its compact design and mass production capability.

[0004] Current power unit assemblies mainly include motors, reducers, encoders, and drivers. The motor primarily converts electrical energy into kinetic energy; the reducer controls the speed of the motor's output power and increases the output torque; the encoder acquires the motor's position for accurate control; and the driver provides drive control for the motor.

[0005] Planetary reducers are currently the most widely used type of power unit in robots. However, bipolar planetary reducers are used, but they occupy a large amount of space, significantly reducing the space of the power unit assembly and resulting in a large overall size of the power unit assembly. Utility Model Content

[0006] In view of this, this application provides a power unit assembly, a joint module, and a legged robot, which improves the compactness of the power unit assembly and reduces its volume.

[0007] In a first aspect, a power unit assembly is provided, which is applied to a legged robot. The legged robot includes a first joint component and a second joint component rotatably connected by the power unit assembly. The power unit assembly includes: a motor, a high-speed planetary reducer, and a low-speed planetary reducer; wherein the motor, the high-speed planetary reducer, and the low-speed planetary reducer are arranged sequentially along the axis of the motor.

[0008] The high-speed planetary reducer is connected to the motor drive; The low-speed planetary reducer is connected to the high-speed planetary reducer, and the high-speed planetary reducer is partially embedded in the low-speed planetary reducer along the axial direction of the motor.

[0009] In the above technical solution, by using the axial engagement of the high-speed end planetary reducer and the low-speed end planetary reducer, the two are coupled, thereby reducing the size of the power unit assembly in the axial direction, improving the compactness of the power unit assembly, and reducing the volume of the power unit assembly.

[0010] In one specific implementation, the high-speed end planetary reducer includes a first planetary cage, and the low-speed end planetary reducer includes a second planetary cage. The second planetary cage is provided with a receiving cavity; The first planetary cage is partially embedded into the receiving cavity. By creating a receiving cavity in the second planetary cage and inserting the first planetary cage into the receiving cavity, nesting between the two planetary reducers is achieved, reducing the axial dimension of the power unit assembly.

[0011] In one specific implementation scheme, the end face of the first planetary gear of the high-speed planetary reducer that is close to the motor is the first end face; The end face of the first planetary cage closest to the motor is the second end face; The vertical distance between the first end face and the second end face is H1; If the first planetary cage is embedded to a depth H2 into the receiving cavity, then: 1 < H1: H2 ≤ 3: 2. The depth to which the first planetary cage is inserted into the second planetary cage ensures the structural strength of the two planetary cages while maximizing nesting, thus reducing the axial dimension of the power unit assembly.

[0012] In one specific implementation, the first planetary gear of the high-speed planetary reducer is rotatably connected to the first planetary cage via a first rotating shaft, and the first rotating shaft is partially embedded in the receiving cavity. By embedding the rotating shaft into the receiving cavity, the size of the nested two planetary cages is increased, and the axial dimension of the power unit assembly is reduced.

[0013] In one specific implementation, the vertical distance from the axis of any of the first planetary gears of the high-speed end planetary reducer to the axis of the motor is d1, and the radius of the first planetary gear is r1. The perpendicular distance from the axis of any second planetary gear of the low-speed end planetary reducer to the axis of the motor is d2; The minimum vertical distance from the sidewall of the receiving cavity to the axis of the motor is d3; Then the following conditions are met: d1 < d3 < d2; d1 + r1 > d3. The first planetary gear is exposed outside the housing cavity, ensuring the design freedom of the high-speed planetary reducer.

[0014] In one specific implementation, the second planetary cage includes a second inner planetary cage and a second outer planetary cage, the second inner planetary cage and the second outer planetary cage being fixedly connected and forming a space for accommodating the second planetary gear; wherein the accommodating cavity is disposed in the second inner planetary cage; the second outer planetary cage serves as the output end of the power unit assembly. By using the second outer planetary cage as the output end of the power unit assembly, an additional output end is eliminated, reducing the axial dimension of the power unit assembly.

[0015] In one specific feasible implementation, a housing is also included; The first gear ring of the high-speed planetary reducer is fixedly connected to the housing, and the first sun gear of the high-speed planetary reducer is fixedly connected to the output end of the motor. The second gear ring of the low-speed planetary reducer is fixedly connected to the housing; the second sun gear of the low-speed planetary reducer is fixedly connected to the first planetary cage. The second planetary outer cage is rotatably connected to the housing, and there is a seal between the second planetary outer cage and the housing; The second planetary outer cage portion is exposed outside the housing. This exposure facilitates connection to components of the legged robot, and the dynamic seal between the second planetary outer cage and the housing improves the sealing performance of the power unit assembly.

[0016] In one specific implementation, the number of teeth of the first planetary gear of the high-speed end planetary reducer is Z1, and the number of teeth of the first sun gear of the high-speed end planetary reducer is Z2. The number of teeth on the second planetary gear of the low-speed end planetary reducer is Z3, and the number of teeth on the second sun gear of the low-speed end planetary reducer is Z4. Then the following conditions are met: 7≥Z1 / Z2≥4; 7≥Z3 / Z4≥4. Both the high-speed and low-speed planetary reducers have large reduction ratios, allowing for more flexible design.

[0017] Secondly, a joint module is provided, comprising a first joint component, a second joint component, and the power unit assembly described in any one of the preceding embodiments; wherein... The first joint component and the second joint component are rotatably connected through the power unit assembly; the motor is fixed relative to the first joint component, and the output end of the low-speed planetary reducer is fixed relative to the second joint component.

[0018] In the above technical solution, by using the axial engagement of the high-speed end planetary reducer and the low-speed end planetary reducer, the two are coupled, thereby reducing the size of the power unit assembly in the axial direction, improving the compactness of the power unit assembly, and reducing the volume of the power unit assembly.

[0019] Thirdly, a legged robot is provided, the legged robot comprising a body, an articulated arm, and a power unit assembly as described in any one of the above embodiments; wherein... The main body and the articulated arm are rotatably connected via the power unit assembly; The motor is fixed relative to the main body; the output end of the low-speed planetary reducer is fixed relative to the articulated arm.

[0020] In the above technical solution, by using the axial engagement of the high-speed end planetary reducer and the low-speed end planetary reducer, the two are coupled, thereby reducing the size of the power unit assembly in the axial direction, improving the compactness of the power unit assembly, and reducing the volume of the power unit assembly.

[0021] In one specific implementation, the legged robot is a bipedal robot or a quadrupedal robot. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly described below. These drawings are incorporated in and constitute a part of this specification. They illustrate embodiments conforming to this application and, together with the specification, serve to explain the technical solutions of this application. It should be understood that the following drawings only show some embodiments of this application and should not be considered as limiting the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This illustration shows an application scenario of the power unit assembly provided in this application for a quadruped robot.

[0024] Figure 2 This illustration shows an application scenario of the power unit assembly provided in this embodiment of the application in a bipedal robot.

[0025] Figure 3 A schematic diagram of the overall structure of the power unit assembly provided in the embodiment of this application is shown.

[0026] Figure 4 An exploded view of the power unit assembly provided in an embodiment of this application is shown.

[0027] Figure 5A top view of the power unit assembly provided in an embodiment of this application is shown.

[0028] Figure 6 It shows Figure 5 Sectional view at point AA.

[0029] Figure 7 An exploded view of the interface between the high-speed planetary reducer and the low-speed planetary reducer provided in the embodiments of this application is shown.

[0030] Figure 8 A cross-sectional view is shown when the high-speed planetary reducer and the low-speed planetary reducer provided in the embodiments of this application are used together.

[0031] Explanation of reference numerals in the attached figures: 100-Power Unit Assembly 110-Motor 111-Stator 112-Rotor 120-High-speed planetary reducer; 121-First planetary cage; 122-First planetary gear; 123-First ring gear; 124-First sun gear; 125-First end; 126-First shaft 130 - Low-speed planetary reducer; 131 - Second planetary cage; 1311 - Second inner planetary cage; 1312 - Second outer planetary cage; 132 - Second planetary gear; 133 - Second ring gear; 134 - Second sun gear; 135 - Second end; 136 - Receiving cavity; 137 - Second shaft; 138 - Support shaft; 139 - Bearing 140 - Shell; 141 - Main Body; 142 - First End Cap; 143 - Second End Cap 200-First joint component 300 - Second Joint Component Detailed Implementation To more clearly illustrate the technical solutions in the embodiments of this application, the specific implementation methods of this application will be described below with reference to the accompanying drawings. The accompanying drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without creative effort. Adjustments and improvements made without departing from the concept of this application are all within the protection scope of this application.

[0032] To keep the drawings simple, each figure only schematically shows the parts related to the corresponding embodiment, and they do not represent the actual structure of the product. In addition, for the sake of simplicity and ease of understanding, some figures only schematically show parts of components with the same structure or function, and there may actually be more or fewer components with the same structure or function.

[0033] Unless otherwise defined, the technical or scientific terms used in the claims and description shall have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms “first,” “second,” and similar terms used in the patent application description and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. The terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar terms mean that the element or object preceding “comprising” or “including” encompasses the element or object listed following “comprising” or “including” and its equivalents, and do not exclude other elements or objects. The terms “connected,” “coupled,” or “linked” and similar terms are not limited to physical or mechanical connections, nor are they limited to direct or indirect connections.

[0034] Unless otherwise specified, all embodiments mentioned herein can be combined to form new technical solutions. Furthermore, unless otherwise specified, all technical features and preferred features mentioned herein can be combined to form new technical solutions.

[0035] In this application, the terms "or" and "and / or" describe the relationship between related objects and indicate a non-exclusive inclusion. For example, "A and / or B" and "A or B" can include: only "A" exists, only "B" exists, and both "A" and "B" exist simultaneously, where "A" and "B" can be singular or plural. As another example, "A, B, and / or C" and "A, B, or C" can include: only "A" exists, only "B" exists, only "C" exists, both "A" and "B" exist simultaneously, both "A" and "C" exist simultaneously, both "B" and "C" exist simultaneously, and both "A", "B", and "C" exist simultaneously, where "A", "B", and "C" can be singular or plural. Furthermore, the symbol " / " in this application indicates an "or" relationship between the related objects before and after the symbol. In this application, the term "at least one A or B" has the same meaning as the aforementioned "A or B". The term "at least one A, B, or C" has the same meaning as "A, B, or C" above. "One or more" of multiple objects refers to any one or any combination of multiple objects, such as "one or more of A, B, and C" including: "A alone", "B alone", "C alone", "A and B", "A and C", "B and C", or "A, B, and C".

[0036] To facilitate understanding of the power unit assembly provided in the embodiments of this application, the application scenario of the power unit assembly provided in the embodiments of this application will first be described. The power unit assembly provided in the embodiments of this application is applied to legged robots. However, current power unit assemblies are large in size and occupy a lot of space, which is not conducive to miniaturization. Therefore, the embodiments of this application provide a power unit assembly to improve the compactness of the power unit assembly and facilitate its miniaturization. The following is a detailed description with reference to specific drawings and embodiments.

[0037] The power unit assembly provided in this application embodiment is applied in a legged robot to provide the power required for the rotation of the joint modules in the legged robot. For example, the legged robot includes a first joint component and a second joint component, wherein the first joint component and the second joint component are rotatable relative to each other. The power unit assembly is used to rotatably connect the first joint component and the second joint component, and drives the second joint component to move relative to the first joint component.

[0038] Please refer to the above. Figure 1 and Figure 2 , Figure 1 and Figure 2 A schematic diagram illustrating an application scenario of the power unit assembly provided in an embodiment of this application is shown. Figure 1 A schematic diagram of the power unit assembly applied to a quadruped robot is shown. Figure 2 A schematic diagram illustrating the application of a power unit assembly in a bipedal robot is shown. Figure 1 and Figure 2 The example illustrates the application of the power unit assembly 100 in a hip joint module. The first joint component 200 is the body of the legged robot, and the second joint component 300 is the leg component. The power unit assembly 100 rotatably connects the body and the leg component and can drive the leg component to rotate relative to the body. In actual operation, the power unit assembly 100 is fixedly connected to the body, while its output end is fixedly connected to the leg component. When the power unit assembly 100 outputs power, the output end can drive the leg component to rotate relative to the body, thereby enabling the legged robot to walk.

[0039] It should be understood that, Figure 1 and Figure 2 The description uses the hip joint module as an example. In this embodiment, the power unit assembly 100 is not limited to the hip joint module in the example above, but can also be applied to other joint modules in legged robots, such as the knee joint module, wrist joint module, and other modules that require relative rotation.

[0040] refer to Figure 3 and Figure 4 As shown, Figure 3This paper shows a schematic diagram of the overall structure of the power unit assembly provided in an embodiment of this application. Figure 4 An exploded view of the power unit assembly provided in this embodiment is shown. The power unit assembly 100 provided in this embodiment includes a motor 110 and a reducer; wherein the reducer is a planetary reducer, and employs two stages. Specifically, the two stages of the planetary reducer are a high-speed planetary reducer 120 and a low-speed planetary reducer 130. The high-speed planetary reducer 120 is located close to the motor 110, while the output end of the low-speed planetary reducer 130 serves as the output end of the power unit assembly 100. When the power unit assembly 100 is applied in a joint module, the motor 110 is fixed relative to the first joint component 200, while the output end of the low-speed planetary reducer 130 is fixed relative to the second joint component 300, thereby driving the second joint component 300 to rotate relative to the first joint component 200 through the power output from the low-speed planetary reducer 130.

[0041] During transmission, the high-speed planetary reducer 120 is connected to the motor 110, and the low-speed planetary reducer 130 is connected to the high-speed planetary reducer 120. The higher speed output by the motor 110 is first reduced by the high-speed planetary reducer 120, and then further reduced by the low-speed planetary reducer 130 before being output to the output end of the power unit assembly 100, driving the second joint component 300 to rotate. The two-stage planetary reducer achieves a larger reduction ratio, lowering the output speed and increasing the output torque, thereby providing greater driving force to the second joint component 300.

[0042] Please refer to the above. Figure 5 and Figure 6 As shown, Figure 5 A top view of the power unit assembly provided in an embodiment of this application is shown. Figure 6 for Figure 5 A cross-sectional view at point AA. When the motor 110, high-speed planetary reducer 120, and low-speed planetary reducer 130 are arranged within the power unit assembly 100, they are arranged sequentially along the axis O1 of the motor 110. Specifically, the high-speed planetary reducer 120 is located between the motor 110 and the low-speed planetary reducer 130, so that the power from the motor 110 is transmitted to the low-speed planetary reducer 130 via the high-speed planetary reducer 120. Furthermore, when arranging the high-speed planetary reducer 120 and the low-speed planetary reducer 130, the high-speed planetary reducer 120 is partially embedded within the low-speed planetary reducer 130 along the axial direction of the motor 110. That is, in the axial direction of the motor 110, the high-speed planetary reducer 120 and the low-speed planetary reducer 130 are arranged in a nested manner, thereby coupling the high-speed planetary reducer 120 and the low-speed planetary reducer 130 in the axial direction of the motor 110.

[0043] like Figure 6 As shown, along the axial direction of the motor 110, the axial length of the motor 110 is L1, the axial length of the high-speed planetary reducer 120 is L2, and the axial length of the low-speed planetary reducer 130 is L3. The axial overlap between the high-speed planetary reducer 120 and the low-speed planetary reducer 130 is L4. Therefore, the total length L of the arrangement of the motor 110, the high-speed planetary reducer 120, and the low-speed planetary reducer 130 is: L = L1 + L2 + L3 - L4. This reduces the space occupied by the motor 110, the high-speed planetary reducer 120, and the low-speed planetary reducer 130, improving the compactness of the power unit assembly 100 and reducing its space requirement.

[0044] As can be seen from the above description, in the power unit assembly 100 provided in this application embodiment, the axial cooperation between the high-speed end planetary reducer 120 and the low-speed end planetary reducer 130 is adopted to couple the two, thereby reducing the size of the power unit assembly 100 in the axial direction, improving the compactness of the power unit assembly 100 and reducing the volume of the power unit assembly 100.

[0045] Continue to refer to Figure 3 and Figure 4 As shown, the power unit assembly 100 provided in this embodiment of the application, in addition to the structure described above, may also include a housing 140. The housing 140 is used to house the motor 110, the high-speed planetary reducer 120, and the low-speed planetary reducer 130. The output end of the low-speed planetary reducer 130 is exposed outside the housing 140 and can be fixedly connected to the second joint component 300. When the power unit assembly 100 is applied to the joint module, the housing 140 is fixedly connected to the first joint component 200, and the output end of the low-speed planetary reducer 130 is fixedly connected to the second joint component 300, thereby realizing a rotational connection between the first joint component 200 and the second joint component 300.

[0046] In an optional embodiment, the housing provided in this application can adopt a split structure. For example, the housing 140 includes a main body 141, a first end cover 142, and a second end cover 143. The first end cover 142 and the second end cover 143 are respectively fixedly connected to the main body 141 and form a space to accommodate the motor 110, the high-speed planetary reducer 120, and the low-speed planetary reducer 130, thereby facilitating the assembly of the motor 110, the high-speed planetary reducer 120, and the low-speed planetary reducer 130. Furthermore, it also facilitates subsequent maintenance and component replacement.

[0047] It should be understood that the motor provided in the embodiments of this application may be of different types, such as... Figure 3 and Figure 4As shown, motor 110 is an internal rotor motor, which includes a stator 111 and a rotor 112. The stator 111 is fixedly connected to the housing 140, while the rotor 112 is fixedly connected to the high-speed planetary reducer 120. Of course, in addition to the internal rotor motor of the example, the motor provided in this application embodiment can also be an external rotor motor, and no specific limitation is made in this application embodiment.

[0048] The high-speed planetary reducer 120 and low-speed planetary reducer 130 provided in this application both include the common planetary gear reducer structure such as a ring gear, planetary cage, sun gear, and multiple planetary gears. The sun gear meshes with the planetary gears, the planetary gears mesh with the ring gear, and the planetary cage is rotatably connected to the multiple planetary gears.

[0049] Please refer to the above. Figure 4 and Figure 6 As shown, for ease of description, the components in the high-speed planetary reducer 120 are named the first ring gear 123, the first planetary cage 121, the first sun gear 124, and the first planetary gear 122, respectively; the components in the low-speed planetary reducer 130 are named the second ring gear 133, the second planetary cage 131, the second sun gear 134, and the second planetary gear 132, respectively.

[0050] In an optional embodiment, the first gear ring 123 and the second gear ring 133 provided in this application are fixedly connected to the housing 140. The first sun gear 124 is fixedly connected to the output shaft of the motor 110, and the second sun gear 134 is fixedly connected to the first planetary cage 121. During transmission, the power output by the motor 110 is input to the high-speed planetary reducer 120 through the first sun gear 124, and output to the second sun gear 134 through the first planetary cage 121. The second planetary cage 131 of the low-speed planetary reducer 130 serves as the output end, outputting power to the second joint component 300.

[0051] Please refer to the above. Figure 6 and Figure 7 As shown, Figure 7An exploded view of the mating parts of the high-speed planetary reducer and the low-speed planetary reducer is shown. In one feasible embodiment, the end of the high-speed planetary reducer 120 facing away from the motor 110 is designated as the first end 125, and the end of the low-speed planetary reducer 130 approaching the motor 110 is designated as the second end 135. The second end 135 is provided with a receiving cavity 136, and the first end 125 is partially embedded within the receiving cavity 136. With the above structure, the receiving cavity 136 is provided at the second end 135 of the low-speed planetary reducer 130 to provide space for accommodating the high-speed planetary reducer 120. In specific arrangements, the receiving cavity 136 can be implemented by through holes, notches, or grooves formed on the second end 135; no specific limitation is made in this embodiment.

[0052] In an alternative embodiment, the second end 135 of the low-speed planetary reducer 130 is the end of the second planetary cage 131 facing the motor 110, and therefore, a receiving cavity 136 is formed in the second planetary cage 131. The first end 125 of the high-speed planetary reducer 120 is the end of the first planetary cage 121 facing away from the motor 110. When the high-speed planetary reducer 120 and the low-speed planetary reducer 130 are engaged, the first planetary cage 121 is partially embedded in the receiving cavity 136 formed in the second planetary cage 131, thereby causing the two planetary cages to overlap in the axial direction of the motor 110, so as to reduce the size of the power unit assembly in the axial direction of the motor 110.

[0053] In one optional embodiment, for ease of description, a first end face and a second end face are defined. The first end face is the end face of the first planetary gear 122 of the high-speed planetary reducer 120 near the motor 110, and the second end face is the end face of the first planetary cage 121 near the motor 110. The vertical distance between the first and second end faces is H1; the depth to which the first planetary cage is embedded in the receiving cavity is H2, then: 1 < H1 : H2 ≤ 3 : 2. For example, the ratio of H1 to H2 can be different values ​​such as 1.1, 1.2, 1.3, and 1.5. Using the above dimensions, while ensuring the structural strength of the first planetary cage 121 and the second planetary cage 131, the first planetary cage 121 can be inserted to the maximum depth into the receiving cavity 136, thereby minimizing the axial dimension of the power unit assembly.

[0054] In an alternative embodiment, the first planetary gear 122 is rotatably connected to the first planetary cage 121 via a first rotating shaft 126. When the first planetary cage 121 and the second planetary cage 131 are specifically nested, the first rotating shaft 126 is partially nested into the receiving cavity 136. For example... Figure 8As shown, the shaft 126 connected to the first planetary gear 122 is partially embedded in the receiving cavity 136, thereby increasing the nesting size of the first planetary cage 121 and the second planetary cage 131 and reducing the axial dimension of the power unit assembly.

[0055] In an alternative embodiment, the receiving cavity 136 is a through hole formed in the second planetary cage 131. Using a through hole facilitates fabrication on the second planetary cage 131 and maximizes the depth of the receiving cavity 136, thereby increasing the overlap between the high-speed planetary reducer 120 and the low-speed planetary reducer 130 in the axial direction of the motor 110, i.e., increasing L4.

[0056] In one alternative, the receiving cavity 136 is a circular receiving cavity to accommodate the rotation of the first planetary cage 121, minimizing the impact on the structural strength of the second planetary cage 131.

[0057] Continue to refer to Figure 7 and Figure 8 As shown, multiple first planetary gears 122 are arranged in a ring, spaced apart around the first sun gear 124, and multiple second planetary gears 132 are arranged in a ring, spaced apart around the second sun gear 134. Furthermore, when the high-speed planetary reducer 120 and the low-speed planetary reducer 130 are nested, the first planetary gears 122 can be located outside the receiving cavity 136, ensuring greater freedom in designing the dimensions of the first sun gear 124 and the first planetary gears 122 in the high-speed planetary reducer 120.

[0058] Continue to refer to Figure 8In one feasible embodiment, the radius of the first planetary gear 122 is r1, and the radius of the annulus formed by the plurality of first planetary gears 122 is d1, that is, the perpendicular distance from the axis of any first planetary gear 122 to the axis O1 of the motor 110 is d1. Similarly, the radius of the annulus formed by the plurality of second planetary gears 132 is d2, that is, the perpendicular distance from the axis of any second planetary gear 132 to the axis O1 of the motor 110 is d2. The minimum perpendicular distance from the sidewall of the receiving cavity 136 to the axis O1 of the motor 110 is d3. Therefore, when arranging the receiving cavity 136, the following conditions are satisfied: d1 < d3 < d2; d1 + r1 > d3. For example, the first planetary gear 122 is rotatably connected to the first planetary cage 121 through the first rotating shaft 126, and the second planetary gear 132 is rotatably connected to the second planetary cage 131 through the second rotating shaft 137. When the high-speed planetary reducer 120 and the low-speed planetary reducer 130 are nested, the receiving cavity 136 is located within the circular area enclosed by the second rotating shaft 137, and the first rotating shaft 126 can be partially embedded into the receiving cavity 136. This increases the overlap between the high-speed planetary reducer 120 and the low-speed planetary reducer 130 in the axial direction of the motor 110, i.e., increases L4. In addition, the first planetary gear 122 is exposed outside the receiving cavity 136, which allows for a more flexible gear ratio design for the high-speed planetary reducer 120, improving the design flexibility of the high-speed planetary reducer 120.

[0059] In an optional embodiment, the second sun gear 134 provided in this application is fixedly connected to the first planetary cage 121 via a support shaft 138, and the support shaft 138 is rotatably connected to the second planetary cage 131 via a bearing 139. The support shaft 138 has a stepped surface that abuts against the inner ring of the bearing. Exemplarily, a stepped structure (not shown in the figure) is provided at the end of the support shaft 138 away from the first planetary cage 121, and the bearing 139 is provided on the second planetary cage 131; the step surface of the stepped structure abuts against the inner ring of the bearing 139 to axially limit the second sun gear 134 and limit the depth to which the first planetary cage 121 is embedded into the receiving cavity 136, thereby ensuring that there is no interference between the second planetary gear 132 and the first planetary cage 121 during rotation.

[0060] In an optional embodiment, the first planetary gear 122 has Z1 teeth, and the first sun gear 124 has Z2 teeth, satisfying 7 ≥ Z1 / Z2 ≥ 4. The second planetary gear 132 has Z3 teeth, and the second sun gear 134 has Z4 teeth, satisfying 7 ≥ Z3 / Z4 ≥ 4. Within the aforementioned range of tooth counts, the arrangement between the first sun gear 124 and the first planetary gear 122 in the high-speed planetary reducer 120 can have a higher degree of freedom, as can the arrangement between the second sun gear 134 and the second planetary gear 132 in the low-speed planetary reducer 130. This allows the planetary reducer composed of the high-speed planetary reducer 120 and the low-speed planetary reducer 130 to be adjusted within a wider range of reduction ratios as needed.

[0061] In an optional embodiment, the first planetary carrier 121 provided in this application embodiment may be an integral planetary carrier to improve the support strength for the first planetary gear 122.

[0062] In one alternative embodiment, the second planetary cage 131 can be either a one-piece structure or a separate structure. For example, Figure 7 and Figure 8 As shown, when the second planetary cage 131 adopts a split structure, it includes an inner second planetary cage 1311 and an outer second planetary cage 1312. The inner second planetary cage 1311 and the outer second planetary cage 1312 are fixedly connected and form a space to accommodate the second planetary gear 132. When the high-speed planetary reducer 120 and the low-speed planetary reducer 130 are nested, the receiving cavity 136 is located in the inner second planetary cage 1311. The outer second planetary cage 1312 serves as the output end of the power unit assembly. When the power unit assembly is assembled into a legged robot, the outer second planetary cage 1312 is fixedly connected to the second joint component 300. This allows the low-speed planetary reducer 130 to be directly connected to the second joint component 300 without the need for an additional output end, reducing the axial dimension of the power unit assembly. Furthermore, the split structure of the outer second planetary cage 1312 also facilitates its fabrication.

[0063] In one example, the second planetary outer cage 1312 provided in this embodiment is partially exposed outside the housing 140 to facilitate connection with components of the legged robot (such as the second joint component). Furthermore, the second planetary outer cage 1312 is rotatably connected to the housing 140, and the second planetary cage 131 is sealed to the housing 140, improving the sealing performance of the power unit assembly. With this structure, the second planetary outer cage 1312 serves as the output end of the power unit assembly and is connected to the second joint component 300, eliminating the need for a separate adapter to connect the second planetary cage 131 to the second joint component 300. This further reduces the axial dimension of the power unit assembly 100, facilitating miniaturization of the power unit assembly 100.

[0064] When the housing is a split structure, the first end cap 142 is an annular structure, and the second planetary outer cage 1312 is inserted into the hollow area of ​​the first end cap 142 and can rotate relative to the first end cap 142. That is, the end of the second planetary cage 131 that is away from the first planetary cage 121 is exposed outside the housing 140 to facilitate its fixed connection with the second joint component 300.

[0065] In one example, a groove is provided on the annular inner wall of the first end cap 142, and a seal can be provided in the groove to seal the first end cap 142 with the second planetary outer cage 1312. Of course, in addition to sealing with a seal as described above, the second planetary cage 1312 can also be sealed with an oil seal or other sealing methods to seal the first end cap 142.

[0066] It should be understood that, in addition to the sealing positions in the examples above, seals may also be provided at the connection positions of other components of the housing 140 in this application to ensure the airtightness of the space enclosed by the housing, thereby better protecting the motor 110, the high-speed planetary reducer 120 and the low-speed planetary reducer 130.

[0067] In addition to the housing 140, motor 110, low-speed planetary reducer 130, and high-speed planetary reducer 120 mentioned above, the power unit assembly 100 provided in this application embodiment may also include a drive board for controlling the rotation of the motor 110 and a detection component for detecting the rotation angle of the motor 110, etc., which will not be described in detail here.

[0068] This application embodiment also provides a joint module, which includes a first joint component 200, a second joint component 300, and a power unit assembly 100 of any of the above; wherein the first joint component 200 and the second joint component 300 are rotatably connected through the power unit assembly 100, and the motor 110 is fixed relative to the first joint component 200; the output end of the low-speed planetary reducer 130 is fixed relative to the second joint component 300.

[0069] In the above technical solution, by adopting the axial cooperation of the high-speed end planetary reducer 120 and the low-speed end planetary reducer 130, the two are coupled, thereby reducing the size of the power unit assembly 100 in the axial direction, improving the compactness of the power unit assembly 100 and reducing the volume of the power unit assembly 100.

[0070] This application also provides a legged robot, which includes a body, an articulated arm, and a power unit assembly 100 as described above; wherein the body and the articulated arm are rotatably connected via the power unit assembly 100; a motor 110 is fixed relative to the body; and the output end of a low-speed planetary reducer 130 is fixed relative to the articulated arm. Figure 1 and Figure 2 As shown, the main body can be a first joint component 200, and the joint arm can be a second joint component 300.

[0071] In the above technical solution, by adopting the axial cooperation of the high-speed end planetary reducer 120 and the low-speed end planetary reducer 130, the two are coupled, thereby reducing the size of the power unit assembly 100 in the axial direction, improving the compactness of the power unit assembly 100 and reducing the volume of the power unit assembly 100.

[0072] In one specific feasible implementation, the legged robot is either a bipedal robot or a quadrupedal robot. See the attached document for details. Figure 1 and Figure 2 As shown in the figure, it will not be elaborated further here.

[0073] Furthermore, the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above 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.

[0074] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The protection scope of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the technical scope disclosed in this application; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application. All should be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A power unit assembly applied to a legged robot, the legged robot comprising a first joint component and a second joint component rotatably connected via the power unit assembly, characterized in that, The power unit assembly includes: a motor, a high-speed planetary reducer, and a low-speed planetary reducer; wherein the motor, the high-speed planetary reducer, and the low-speed planetary reducer are arranged sequentially along the axis of the motor. The high-speed planetary reducer is connected to the motor drive; The low-speed planetary reducer is connected to the high-speed planetary reducer in a transmission manner; along the axial direction of the motor, the high-speed planetary reducer is partially embedded in the low-speed planetary reducer.

2. The power unit assembly according to claim 1, characterized in that, The high-speed end planetary reducer includes a first planetary cage, and the low-speed end planetary reducer includes a second planetary cage. The second planetary cage is provided with a receiving cavity; The first planetary cage portion is embedded into the receiving cavity.

3. The power unit assembly according to claim 2, characterized in that, The first planetary gear of the high-speed planetary reducer has a first end face near the motor. The end face of the first planetary cage closest to the motor is the second end face; The vertical distance between the first end face and the second end face is H1; If the first planetary cage is embedded to a depth H2 into the receiving cavity, then: 1 < H1: H2 ≤ 3:

2.

4. The power unit assembly according to claim 2, characterized in that, The first planetary gear of the high-speed end planetary reducer is rotatably connected to the first planetary cage via a first rotating shaft, and the first rotating shaft is partially embedded in the receiving cavity.

5. The power unit assembly according to claim 4, characterized in that, The vertical distance from the axis of any first planetary gear of the high-speed end planetary reducer to the axis of the motor is d1, and the radius of the first planetary gear is r1. The perpendicular distance from the axis of any second planetary gear of the low-speed end planetary reducer to the axis of the motor is d2. The minimum vertical distance from the sidewall of the receiving cavity to the axis of the motor is d3; Then it satisfies: d1 < d3 < d2; d1+r1>d3.

6. The power unit assembly according to any one of claims 2 to 5, characterized in that, The second planetary cage includes a second inner planetary cage and a second outer planetary cage. The second inner planetary cage and the second outer planetary cage are fixedly connected and form a space for accommodating the second planetary gear of the low-speed end planetary reducer. The receiving cavity is disposed within the retainer of the second planetary structure; The second planetary outer cage serves as the output terminal of the power unit assembly.

7. The power unit assembly according to claim 6, characterized in that, It also includes the casing; The first gear ring of the high-speed planetary reducer is fixedly connected to the housing, and the first sun gear of the high-speed planetary reducer is fixedly connected to the output end of the motor. The second gear ring of the low-speed planetary reducer is fixedly connected to the housing; the second sun gear of the low-speed planetary reducer is fixedly connected to the first planetary cage. The second planetary outer cage is rotatably connected to the housing, and there is a seal between the second planetary outer cage and the housing; The second planetary outer cage portion is exposed outside the housing.

8. The power unit assembly according to claim 6, characterized in that, The second sun gear of the low-speed planetary reducer is fixedly connected to the first planetary cage via a support shaft; the support shaft is rotatably connected to the second planetary outer cage via a bearing; and the support shaft has a stepped surface that abuts against the inner ring of the bearing.

9. The power unit assembly according to claim 6, characterized in that, The number of teeth on the first planetary gear of the high-speed end planetary reducer is Z1, and the number of teeth on the first sun gear of the high-speed end planetary reducer is Z2. The number of teeth on the second planetary gear of the low-speed end planetary reducer is Z3, and the number of teeth on the second sun gear of the low-speed end planetary reducer is Z4. Then it satisfies: 7≥Z1 / Z2≥4; 7≥Z3 / Z4≥4.

10. A joint module, characterized in that, It includes a first joint component, a second joint component, and a power unit assembly as described in any one of claims 1 to 9; wherein, The first joint component and the second joint component are rotatably connected through the power unit assembly; the motor is fixed relative to the first joint component, and the output end of the low-speed planetary reducer is fixed relative to the second joint component.

11. A legged robot, characterized in that, Includes a body, an articulated arm, and a power unit assembly as described in any one of claims 1 to 9; wherein, The main body and the articulated arm are rotatably connected via the power unit assembly; The motor is fixed relative to the main body; the output end of the low-speed planetary reducer is fixed relative to the articulated arm.

12. The legged robot according to claim 11, characterized in that, The legged robot is either a bipedal robot or a quadrupedal robot.

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