High power density joint motor for a robot dog

Abstract

The utility model discloses a kind of high-power density joint motors for robot dog, including stator and rotor;The stator includes stator shell, and the inside of the stator shell is equipped with the mounting hole for rotor insertion, the stator shell is equipped with 24 stator slots of equal-division degree setting in the inner wall circumferential side of mounting hole, stator slot is all equipped with fractional slot concentrated winding;The rotor includes hollow shaft, and the outside of the hollow shaft is equipped with 28 magnetic steel of equal distribution setting;The both sides of the magnetic steel are provided with chamfer, to change the magnetic pole shape of magnetic steel;So that magnetic field can realize more gentle transition in magnetic pole edge area;Magnetic steel and the inner wall of mounting hole form unequal air gap under the action of chamfer;The utility model can output higher power under same volume and weight, meet the power demand of robot dog under complex action and high load condition, so that robot dog has stronger movement ability and load capacity.

Description

Technical Field

[0001] This utility model relates to the field of motor technology, specifically a high power density joint motor for a robot dog. Background Technology

[0002] With the continuous development of robotics technology, robot dogs, as a typical biomimetic robot, have been widely used in many fields such as inspection, security, and rescue. The joint motors of robot dogs, as key components, play a decisive role in their motion performance, load capacity, and endurance. Currently, existing joint motors have insufficient power density, limiting the further development and application of robot dogs. For example, they cannot meet the power requirements of robot dogs under complex movements and high loads, or they result in excessively large and heavy robot dogs, affecting their flexibility and maneuverability. Therefore, developing a high-power-density joint motor for robot dogs is of significant practical importance. Utility Model Content

[0003] To address the shortcomings of existing joint motors in terms of power density, which limit the further development and application of robot dogs, such as failing to meet the power requirements of robot dogs under complex actions and high loads, or causing the overall size and weight of robot dogs to be too large, affecting their flexibility and maneuverability, this utility model provides a high power density joint motor for robot dogs.

[0004] To solve the above-mentioned technical problems, this utility model provides the following technical solution:

[0005] This utility model discloses a high-power-density joint motor for a robot dog, comprising a stator and a rotor; the stator includes a stator housing, and the interior of the stator housing is provided with mounting holes for the rotor to be inserted; the stator housing has 24 stator slots equally spaced on the inner circumference of the mounting holes, and each stator slot is provided with a fractional-slot concentrated winding; the rotor includes a hollow shaft, and 28 magnets equally distributed on the outer side of the hollow shaft;

[0006] The magnet has beveled edges on both sides to change the shape of the magnetic poles, so that the magnetic field can transition more smoothly in the edge region of the magnetic poles, and the magnetic flux generated by the beveled magnet is more closely related to the ideal sine function shape in space; the beveled edges also create unequal air gaps between the magnet and the inner wall of the mounting hole.

[0007] As a preferred technical solution of this utility model, the fractional slot concentrated winding is provided with multiple layered windings arranged in layers, and an insulating layer is provided between the multiple layered windings; the multiple layered windings are arranged in parallel; after the layered windings are completed, a vacuum pressure impregnation process is used to immerse the layered windings in insulating varnish, and the air inside the layered windings is removed in a vacuum environment. Then, a certain pressure is applied to make the insulating varnish fully penetrate into all gaps of the layered windings, including between the conductors and between the windings and the iron core.

[0008] As a preferred embodiment of this utility model, the inner wall of the stator slot is covered with a layer of polyimide fiber paper.

[0009] As a preferred technical solution of this utility model, the outer wall of the hollow shaft is provided with a plurality of inwardly recessed positioning grooves, and the outer end of the magnet is embedded in the positioning groove and fixed by an adhesive layer, and the outer arm of the hollow shaft is also provided with a spiral glue storage groove.

[0010] As a preferred technical solution of this utility model, the side wall of the hollow shaft is provided with a plurality of limiting grooves that correspond one-to-one with the positioning grooves and are arranged along the axial direction of the hollow shaft. One end of the limiting groove is provided with an opening and the other end of the limiting groove is a closed end. The back side of the magnet is provided with an insert that is inserted into the limiting groove. The outer end of the hollow shaft is also provided with a closing ring block for closing the opening of the limiting groove. The closing ring block is provided with an elastic abutting block for the end of the insert to abut against it. The closing ring block is welded to the end face of the shaft end of the hollow shaft.

[0011] As a preferred technical solution of this utility model, the hollow shaft has an inwardly recessed storage groove at its shaft end for accommodating the closed ring block.

[0012] As a preferred technical solution of this utility model, the surface of the closed ring block is provided with an injection hole for injecting adhesive layer into the limiting groove, so as to fill the gap between the magnet and the hollow shaft, and the gap between the insert and the limiting groove.

[0013] As a preferred technical solution of this utility model, the stator housing is further provided with a rubber heat-conducting tube coiled around the periphery of the fractional slot concentrated winding, and the two ends of the rubber heat-conducting tube extend out of the motor housing respectively, and are respectively connected to a coolant inlet pipe and a coolant outlet pipe. A liquid storage tank is also provided outside the motor housing, and the liquid storage tank, coolant inlet pipe, and coolant outlet pipe form a circulating liquid path through a liquid guide pipe, and a circulating pump is provided on the liquid guide pipe.

[0014] As a preferred technical solution of this utility model, the liquid storage tank is made of metal and has multiple heat dissipation fins on its surface.

[0015] As a preferred embodiment of this utility model, a pressure gauge is provided on the coolant outlet pipe.

[0016] The beneficial effects of this utility model are:

[0017] 1. The high-power-density joint motor used in this type of robot dog employs a 28-pole, 24-slot configuration, which enables a more rational distribution of the magnetic field inside the motor. This effectively avoids the effects of unbalanced magnetic pull, making the interaction between the magnetic field generated by the stator winding and the magnetic field of the rotor permanent magnet more uniform and coordinated. This helps to improve the motor's performance, such as efficiency and power factor.

[0018] 2. The high power density joint motor for this type of robot dog uses fractional slot concentrated windings, which can significantly reduce the length of the winding ends. Compared with traditional integer slot distributed windings, the space occupied at the ends is greatly reduced. Each phase winding is closely concentrated in a specific slot, avoiding excessive extension of the winding ends, thereby reducing the amount of copper used, reducing winding resistance, and thus reducing copper loss and improving motor efficiency. This advantage is more obvious, especially when running at high frequencies, which helps to improve the overall performance and power density of the motor.

[0019] 3. This type of robotic dog uses a high-power-density joint motor. By rationally cutting the edges and corners of the magnets, the shape of the magnet poles is altered, allowing for a smoother transition of the magnetic field at the pole edges. The magnetic flux generated by the cut magnets has a spatial distribution closer to an ideal sinusoidal function, effectively reducing harmonic content. A non-uniform air gap is established between the magnets and the rotor or stator. By reducing the air gap length in the central region of the poles, the air gap magnetic flux density in that region is significantly increased, thereby enhancing the energy density of the magnetic field. This means that under the same current input, the motor can generate greater electromagnetic torque, directly increasing the motor's output power. Simultaneously, the appropriately increased air gap at the pole edges reduces distortion and leakage magnetic field at the edges, resulting in a more rational magnetic field distribution and further improving magnetic field utilization efficiency, contributing to increased power density.

[0020] 4. This type of high-power-density joint motor for robotic dogs employs a multi-layer winding design with parallel connections. With the same stator slot size, the multi-layer winding allows for more efficient use of the slot space by arranging the wires in layers, thereby increasing the cross-sectional area of ​​the wires. This means that at the same current density, the motor can carry a larger current, thus increasing the motor's output power and torque density, resulting in more powerful performance without changing its size.

[0021] 5. This type of robotic dog uses a high-power-density joint motor, which, through the action of a circulating pump, circulates the coolant in a reservoir and through rubber heat-conducting pipes. The rubber heat-conducting pipes are coiled around the periphery of the fractional-slot concentrated winding, thus providing good heat dissipation for the fractional-slot concentrated winding and preventing heat accumulation that could lead to excessively high local temperatures. The reservoir is made of metal and has multiple heat dissipation fins on its surface, facilitating the dissipation and cooling of the coolant. A pressure gauge is installed on the coolant outlet pipe, allowing the internal liquid pressure to be maintained within a reasonable range by adjusting the operating power of the circulating pump, thereby preventing pipe bursting. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0023] Figure 1 This is a schematic diagram of the structure of a high power density joint motor for a robot dog according to this utility model;

[0024] Figure 2 This is a schematic diagram of the unequal air gap structure of a high power density joint motor for a robot dog according to this utility model;

[0025] Figure 3 This is a schematic diagram of the stator slot structure of a high power density joint motor for a robot dog according to this utility model;

[0026] Figure 4 This is a schematic diagram of the spiral glue storage tank of a high power density joint motor for a robot dog according to this utility model.

[0027] Figure 5 This is a schematic diagram of the structure of a high-power-density joint motor insert for a robot dog according to this utility model;

[0028] Figure 6 This is a schematic diagram of the limiting groove of a high power density joint motor for a robot dog according to this utility model;

[0029] Figure 7 This is a schematic diagram of the limiting groove of a high power density joint motor for a robot dog according to this utility model;

[0030] Figure 8 This is a schematic diagram of the structure of the magnet of a high power density joint motor for a robot dog according to this utility model;

[0031] Figure 9 This is a schematic diagram of the liquid storage tank for a high power density joint motor for a robot dog according to this utility model;

[0032] Figure 10This is a schematic diagram of the fractional slot concentrated winding of a high power density joint motor for a robot dog according to this utility model.

[0033] In the diagram: 1. Stator; 101. Stator housing; 102. Mounting hole; 103. Stator slot; 104. Fractional slot concentrated winding; 105. Layered winding; 106. Insulation layer; 2. Rotor; 201. Hollow shaft; 202. Magnet; 203. Chamfer; 204. Unequal air gap; 205. Positioning slot; 206. Spiral rubber storage tank; 207. Limiting slot; 208. Opening; 209. Closed end; 210. Insert; 211. Closed ring block; 212. Elastic contact block; 213. Storage slot; 3. Rubber heat conduction pipe; 4. Coolant inlet pipe; 5. Coolant outlet pipe; 6. Storage tank; 7. Circulation pump; 8. Heat dissipation fins; 9. Pressure gauge. Detailed Implementation

[0034] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0035] Example: Figure 1-10 As shown, this utility model discloses a high-power-density joint motor for a robotic dog, comprising a stator 1 and a rotor 2. The stator 1 includes a stator housing 101, and the interior of the stator housing 101 is provided with mounting holes 102 for the rotor 2 to be inserted. The stator housing 101 has 24 equally spaced stator slots 103 on the inner circumferential side of the mounting holes 102, and each stator slot 103 is provided with a fractional-slot concentrated winding 104. The rotor 2 includes a hollow shaft 201. Traditional solid shafts, while meeting high strength requirements, often result in a large overall weight and high moment of inertia, limiting the rapid response capability and energy efficiency of the equipment. The large-bore hollow shaft design is designed to address these challenges. It aims to reduce weight and moment of inertia through innovative structural design, ensuring sufficient mechanical strength of the shaft, thereby improving the overall performance of the motor and its supporting mechanical structure and meeting the complex and varied movement requirements of the robotic dog.

[0036] The hollow shaft 201 has 28 equally distributed magnets 202 mounted on its outer side. This invention adopts a pole-slot configuration of 28 poles and 24 slots. This configuration makes the magnetic field distribution inside the motor more reasonable, effectively avoids the influence of unbalanced magnetic pull, and makes the interaction between the magnetic field generated by the stator winding and the magnetic field of the rotor permanent magnet more uniform and coordinated. This helps to improve the performance of the motor, such as efficiency and power factor.

[0037] This invention employs a fractional-slot concentrated winding with a winding pitch of 1. Using a fractional-slot concentrated winding significantly reduces the length of the winding ends, drastically reducing the space occupied at the ends compared to traditional integer-slot distributed windings. This is because in a fractional-slot concentrated winding, each phase winding is tightly concentrated within a specific slot, avoiding excessive extension at the winding ends. This reduces the amount of copper used, lowers winding resistance, and consequently reduces copper losses, improving motor efficiency. This advantage is particularly pronounced during high-frequency operation, contributing to enhanced overall motor performance and power density.

[0038] Fractional-slot concentrated windings are advantageous for increasing slot fill factor. Because the fractional-slot concentrated windings are placed within the slots, they do not require the excessive space left in the slots for bending and distribution at the winding ends, as is the case with integer-slot windings. Therefore, the space within the slots can be utilized more fully. A higher slot fill factor means that the cross-sectional area of ​​the conductors can be increased, thereby reducing winding resistance, reducing heat generation, improving motor efficiency and power output capability, enabling the motor to carry larger currents, output higher power, and enhancing the motor's overload capacity and operational stability.

[0039] Fractional-slot concentrated windings can effectively reduce harmonic magnetic fields. During motor operation, harmonic magnetic fields can cause additional losses, torque pulsation, and vibration noise, reducing motor performance and reliability. By rationally selecting the combination of stator slots and poles, the magnetomotive force waveform generated by the windings can be made closer to a sine wave, thereby reducing harmonic content. This results in smoother motor operation at low speeds and less vibration and noise at high speeds, improving motor control accuracy and operational quality.

[0040] Because the winding ends are short and concentrated, heat is dissipated more easily. During motor operation, the heat generated by the windings can be conducted to the housing or heat dissipation device through the shorter end path, avoiding the heat accumulation problem caused by excessively long ends. Especially during high power density operation, good heat dissipation performance can ensure stable motor operation and reduce the risk of failure due to overheating.

[0041] The magnet 202 has chamfered edges 203 on both sides to change the shape of its magnetic poles, allowing for a smoother transition of the magnetic field at the pole edges. This results in a more spatially accurate distribution of the magnetic flux generated by the chamfered magnet 202, closer to an ideal sinusoidal function. The chamfered edges 203 also create unequal air gaps 204 between the magnet 202 and the inner wall of the mounting hole 102. The chamfered design of the magnet in this invention is based on fundamental principles of electromagnetism, primarily involving the control of magnetic field distribution and magnetomotive force. When current flows through the motor windings, a magnetomotive force is generated, interacting with the inherent magnetic field of the magnet to form an air gap magnetic field. The distribution of this magnetic field directly determines the operating characteristics of the motor. Without chamfering, the magnetic field at the edges of the magnet often changes abruptly, easily leading to uneven air gap magnetic flux density, generating harmonic magnetic fields, and causing adverse consequences such as torque fluctuations, vibrations, and additional losses.

[0042] By appropriately shaving the edges and corners of the magnets, the shape of the magnetic poles is altered, allowing for a smoother transition of the magnetic field at the pole edges. The magnetic flux generated by the shaving magnets has a spatial distribution closer to an ideal sinusoidal function, effectively reducing harmonic content. A non-uniform air gap is established between the magnets and the rotor or stator. By reducing the air gap length in the central region of the poles, the air gap magnetic flux density in that region is significantly increased, thereby enhancing the energy density of the magnetic field. This means that under the same current input, the motor can generate greater electromagnetic torque, directly increasing the motor's output power. Simultaneously, the appropriately increased air gap at the pole edges reduces distortion and leakage magnetic field at the edges, resulting in a more rational magnetic field distribution and further improving magnetic field utilization efficiency, contributing to increased power density.

[0043] The fractional-slot concentrated winding 104 comprises multiple layered windings 105, with an insulation layer 106 separating each layered winding 105. These layered windings are connected in parallel. After the layered windings 105 are completed, a vacuum pressure impregnation process is used to immerse them in insulating varnish. Air is removed from the layers under vacuum, and pressure is applied to ensure the insulating varnish fully penetrates the layers of the windings, including the gaps between the conductors and between the windings and the core. This invention employs a multi-layered winding design with parallel connections. With the same stator slot size, the multi-layered windings utilize the slot space more fully by arranging the conductors in layers, thereby increasing the conductor cross-sectional area. This means that at the same current density, the motor can carry a larger current, thus increasing the motor's output power and torque density, resulting in more powerful performance without changing its size.

[0044] The multi-layered winding structure makes the heat conduction path within the winding more complex and dispersed, increasing the heat dissipation area. The gaps between different layers can act as heat dissipation channels, helping heat to be transferred more quickly from the inside of the winding to the outside, reducing the temperature rise of the winding, thereby improving the motor's heat dissipation efficiency and thermal stability, and reducing the risk of insulation aging and motor failure due to overheating.

[0045] By rationally designing the number of layers, turns per layer, and winding method of multi-layer windings, the magnetic field distribution generated by the stator windings can be controlled more precisely. By adjusting the current phase and magnitude of different winding layers, the magnetic field can be made closer to a sinusoidal distribution, reducing harmonic content and mitigating the negative impacts of magnetic field distortion, such as torque pulsation, vibration, and noise, thereby improving the smoothness and efficiency of motor operation.

[0046] In multi-layer windings, adjacent winding layers can be isolated using insulating material, increasing the thickness and number of insulation layers, thereby effectively improving the electrical insulation strength of the windings. This is especially important for high-voltage, high-power motors, as it can prevent short-circuit faults between windings, improve the reliability and safety of the motor, and extend its service life.

[0047] Multi-layer winding design offers greater freedom to adjust winding parameters such as number of turns, wire diameter, and number of layers. The winding design can be flexibly optimized according to specific motor performance requirements, such as output voltage, current, and power factor, to achieve optimal motor performance matching, meet the needs of different application scenarios, and improve the motor's versatility and adaptability.

[0048] The inner wall of the stator slot 103 is lined with a polyimide fiber paper layer 107. The polyimide varnish possesses excellent electrical insulation properties, with a temperature resistance rating up to 180℃, meeting the temperature requirements of general motor operation. Furthermore, it has high mechanical strength, making it less susceptible to damage during winding and coiling processes. The polyimide varnish also exhibits superior high-temperature resistance, with a temperature resistance rating up to 220℃ or even higher, making it suitable for high-power-density, high-heat-generating motors, such as the robotic dog joint motor designed in this project. Under high load and prolonged operation, it effectively protects the conductors and prevents insulation breakdown.

[0049] The slot insulation is precisely cut to fit the stator slot dimensions and shape, ensuring a tight seal against the slot wall without wrinkles or damage. This provides comprehensive insulation protection for the windings. Figure 3 The use of polyimide fiber paper composite material provides excellent electrical insulation properties, effectively isolating the windings from the core to prevent short circuits within the slots, while also withstanding mechanical vibrations and temperature changes during motor operation. This material also has moderate thermal conductivity, facilitating heat conduction from the windings through the slot walls to the core for heat dissipation, thus improving the motor's heat dissipation efficiency.

[0050] The hollow shaft 201 has multiple inwardly recessed positioning grooves 205 on its outer wall, and the outer end of the magnet 202 is embedded in the positioning grooves 205 and fixed by an adhesive layer. The outer arm of the hollow shaft 201 also has a spiral glue storage groove 206. The positioning grooves limit the position of the magnet 202, and the magnet 202 is fixed to the outer wall of the hollow shaft 201 by the adhesive layer. This provides initial fixation, and the spiral glue storage groove 206 enhances the storage and distribution capacity of the glue, thereby greatly improving the adhesion between the shaft and the rotor magnet, ensuring the stable operation of the motor under complex working conditions, and improving the overall reliability and service life of the equipment.

[0051] The hollow shaft 201 has a plurality of limiting grooves 207 arranged along the axial direction of the hollow shaft 201, which correspond one-to-one with the positioning grooves 205. One end of the limiting groove 207 has an opening 208, and the other end of the limiting groove 207 is a closed end 209. The back side of the magnet 202 has an insert 210 that is inserted into the limiting groove. The outer end of the hollow shaft 201 also has a closing ring block 211 for closing the opening 208 of the limiting groove 207. The closing ring block 211 has an elastic abutment block 210 for the end of the insert 210 to abut against it. The closing ring block 211 is welded to the end face of the shaft end of the hollow shaft 201.

[0052] In this way, the magnet 202 is installed on the hollow shaft 201 by side insertion, which plays a role in preventing it from falling off. This avoids the magnet 202 from easily falling off during the rotation of the hollow shaft under long-term operation, thus meeting the requirements of high strength and high reliability operation.

[0053] The hollow shaft 201 has an inwardly recessed groove 212 at its shaft end that accommodates the closed ring block 211, thus ensuring that the end face of the hollow shaft is flat and has a better flat surface.

[0054] The surface of the closed ring block 211 is provided with an injection hole for injecting adhesive into the limiting groove 207 to fill the gap between the magnet 202 and the hollow shaft 201, as well as the gap between the insert 210 and the limiting groove 207. This can improve the overall insulation performance of the winding, enhance mechanical strength, reduce electromagnetic vibration noise, and also facilitate the heat dissipation of the winding, thereby improving the overall power density of the motor.

[0055] The stator housing 101 is also provided with a rubber heat-conducting tube 3 coiled around the periphery of the fractional-slot concentrated winding. Both ends of the rubber heat-conducting tube 3 extend outside the motor housing and are respectively connected to a coolant inlet pipe 4 and a coolant outlet pipe 5. A liquid storage tank 6 is also provided outside the motor housing. The liquid storage tank 6, coolant inlet pipe 4, and coolant outlet pipe 5 form a circulating liquid path via a guide pipe. A circulation pump 7 is provided on the guide pipe. Thus, under the action of the circulation pump, the coolant circulates between the liquid storage tank 6 and the rubber heat-conducting tube 3. The circulation system features a rubber heat-conducting tube 3 coiled around the periphery of the fractional-slot concentrated winding, which effectively dissipates heat and prevents heat accumulation that could lead to excessively high local temperatures. The liquid storage tank 3 is made of metal and has multiple heat dissipation fins 8 on its surface, facilitating the dissipation and cooling of the coolant. A pressure gauge 9 is installed on the coolant outlet pipe 5, allowing the internal liquid pressure to be maintained within a reasonable range by adjusting the operating power of the circulation pump, thus preventing pipe bursts.

[0056] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A high power density joint motor for a robotic dog, characterized in that, The system includes a stator (1) and a rotor (2); the stator (1) includes a stator housing (101), and the stator housing (101) has mounting holes (102) for inserting the rotor (2) inside. The stator housing (101) has 24 stator slots (103) evenly spaced on the inner wall of the mounting holes (102), and each stator slot (103) has a fractional slot concentrated winding (104); the rotor (2) includes a hollow shaft (201), and 28 magnets (202) evenly distributed on the outer side of the hollow shaft (201). The magnet (202) has chamfered corners (203) on both sides to change the shape of the magnetic poles of the magnet (202), so that the magnetic field can achieve a smoother transition in the edge region of the magnetic poles, and the magnetic flux generated by the chamfered magnet (202) is more closely related to the ideal sine function shape in space; the magnet (202) and the inner wall of the mounting hole (102) form an unequal air gap (204) under the action of the chamfered corners (203).

2. The high power density joint motor for a robotic dog according to claim 1, characterized in that, The fractional slot concentrated winding (104) is provided with multiple layered windings (105) arranged in layers, and an insulation layer (106) is provided between the multiple layered windings (105); the multiple layered windings (105) are arranged in parallel.

3. The high power density joint motor for a robotic dog according to claim 1, characterized in that, The inner wall of the stator slot (103) is covered with a layer of polyimide fiber paper.

4. The high power density joint motor for a robotic dog according to claim 1, characterized in that, The hollow shaft (201) has multiple inwardly recessed positioning grooves (205) on its outer wall, and the outer end of the magnet (202) is embedded in the positioning grooves (205) and fixed by an adhesive layer.

5. A high-power-density joint motor for a robotic dog according to claim 4, characterized in that, The hollow shaft (201) is also provided with a spiral glue storage groove (206) on its outer arm.

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