Low-rotating-speed large-torque high-protection outer rotor servo motor

Abstract

The utility model relates to a kind of low-rotational-speed big torque high protection outer rotor servo motor, it includes base, stator assembly and outer rotor assembly;Stator assembly is fixed by injection molding framework and is installed on the mounting reference column of base;Rotor body of outer rotor assembly is fixed with magnet steel, and located outside stator winding, forms outer rotor structure;Wherein the tooth crown portion of stator tooth is designed as variable-diameter curved surface, and magnet steel of rotor body forms unequal air gap cooperation;The cover of base is fixedly connected with rear cover and forms the sealing space of IP65 above protection level, accommodates stator and rotor assembly.In addition, the sealing lead-out wire of stator winding lead-out wire is realized by the sliding cooperation of online hook sliding block and cover gap, and the lead wire of encoder is positioned using wire hook.The utility model is compact in structure, small in axial dimension, high in torque density, good in protection performance, and suitable for servo drive occasion with high installation space and reliability requirements.

Description

Technical Field

[0001] This utility model relates to the field of servo motors, and in particular to a low-speed, high-torque, and highly protected external rotor servo motor. Background Technology

[0002] Servo motors, as core actuators in automated control systems, are widely used in industrial robots, CNC machine tools, precision instruments, and other fields. Traditional servo motors mostly adopt an internal rotor structure, where the permanent magnets are mounted on the internal rotor, while the stator windings are located externally. This structure often requires increasing the axial length or diameter of the motor to achieve high torque output, resulting in increased motor size and weight, making it difficult to meet the urgent needs of modern equipment for compact and lightweight drive sources.

[0003] Furthermore, concentrated winding motors with internal rotor structures have high harmonic content in their air gap magnetic field, which can easily lead to large cogging torque, causing torque and speed fluctuations and affecting the control accuracy and operational stability of the servo system. To reduce cogging torque, existing technologies typically employ methods such as skewed slots and optimized magnet shapes, but these methods often result in complex manufacturing processes, increased costs, or a reduction in the motor's output torque.

[0004] On the other hand, with the diversification of servo motor application environments, higher requirements are being placed on their protection levels. Conventional motors have relatively complex sealing and protection structures, making it difficult to achieve high levels of protection (such as IP65 and above) while ensuring a compact structure, thus limiting their application in harsh industrial environments such as dust and humidity.

[0005] Meanwhile, the position feedback components of the motor (such as encoders) usually require independent installation space, which further increases the axial dimension of the motor and is not conducive to the miniaturization design of the whole machine. The layout and sealing of the motor's lead wires are also key factors affecting its reliability and structural compactness. Existing designs often suffer from problems such as messy wiring and unreliable sealing.

[0006] Therefore, there is an urgent need in this field for a new type of servo motor structure that can effectively reduce axial dimensions, improve protection level, and optimize the layout and wiring of internal components while ensuring high torque output and high control precision. Utility Model Content

[0007] The purpose of this invention is to provide a low-speed, high-torque, and highly protected external rotor servo motor that offers higher power density and torque density within the same volume, while also solving the problem of excessively low protection levels in external rotor motors.

[0008] The technical solution to achieve the purpose of this utility model is as follows: This utility model has a base, a stator assembly, and an outer rotor assembly; the stator assembly includes a stator body and stator windings wound on the stator body; the stator body includes a stator core formed by stacking multiple stator laminations of the same shape along the axis of the stator core, and an injection-molded skeleton that covers the stator core to form an integral part; the outer rotor assembly includes a rotor body with magnets fixedly mounted; the magnets are coaxially arranged with the stator windings and are located outside the stator windings; the stacked stator core includes an annular stator yoke, on which multiple stator teeth are circumferentially distributed; the end of the stator teeth away from the stator yoke is a tooth crown; the end face of the tooth crown facing the magnet on the rotor body is a variable diameter curved surface; the variable diameter curved surface of the stator teeth and the magnets of the rotor body form an unequal air gap fit; The base includes a mounting reference column and a cover; the stator body is fixedly mounted on the mounting reference column; the mounting reference column has a central through hole; a bearing mounting seat is provided in the central through hole; a rotating shaft is fixedly provided at the rotation center of the rotor body; the rotating shaft is rotatably connected to the mounting reference column through a bearing assembled in the bearing mounting seat; the end of the rotating shaft that is not connected to the rotor body passes through the central through hole to form an output end; It also includes a rear cover; the rear cover is fixedly connected to the open end of the cover; the rear cover and the cover form a protective space; the stator assembly and the rotor assembly are located within the protective space.

[0009] Furthermore, the rotor body has a reference through hole at its rotation center; one end of the rotating shaft is fixedly connected to the rotor body and is fixedly disposed in the reference through hole; the end of the rotating shaft fixedly connected to the rotor body is a connecting end; a first mounting groove is provided on the end face of the connecting end of the rotating shaft; a position feedback permanent magnet assembly is fixedly disposed in the first mounting groove; the position feedback permanent magnet assembly includes a permanent magnet bushing and a position feedback permanent magnet disc; the permanent magnet bushing is fixedly installed in the first mounting groove; a second mounting groove is provided on the permanent magnet bushing and is coaxially disposed with the rotating shaft; the opening of the second mounting groove faces the rear cover; the position feedback permanent magnet disc is fixedly connected in the second mounting groove, and the installation height after installation does not exceed the end face of the rotor body with the reference through hole; a magnetic encoder adapted to the position feedback permanent magnet assembly is fixedly installed on the rear cover.

[0010] Furthermore, the rear cover is provided with an installation space for installing a magnetic encoder; the installation space has an opening communicating with the outside; and the opening is provided with a protective cover for closing the opening.

[0011] Furthermore, the mounting space for installing the magnetic encoder is directly opposite the connection end of the rotating shaft.

[0012] Furthermore, the device also includes a hook slider; the hook slider includes a slider body and a hook integrally formed with the slider body; a notch is provided on the circumferential surface of the cover, extending from the end of the cover facing the rear cover towards the output end of the rotating shaft; the notch forms an open insertion port on the end face of the cover facing the rear cover; the slider body of the hook slider is inserted into the open insertion port of the notch, and the slider body and the notch form a sliding fit; after the rear cover is fixedly connected to the cover, it closes the open insertion port of the notch and restricts the hook slider within the notch; after the hook slider is assembled in the notch, the hook is located outside the cover; after the slider body and the notch fit together, a wire-passing notch is formed for the stator winding lead wire to pass through; the stator winding lead wire passes through the wire-passing notch; after the stator winding lead wire passes through, the wire-passing notch is sealed by applying glue, or a sealing component is fixedly installed at the wire-passing notch to allow the lead wire to pass through and to seal the wire-passing notch; After the rear cover and the protective cover plate are fixedly connected, an outlet is formed for the lead wire of the magnetic encoder to pass through; the lead wire of the magnetic encoder passes through the outlet; the outlet is sealed by applying glue after the lead wire of the magnetic encoder passes through; the lead wire of the magnetic encoder passes through the wire hook and is restricted by the wire hook.

[0013] Furthermore, the inner wall of the notch is provided with a slide rail extending along its extension direction; the slider body is provided with a slide groove that slides and engages with the slide rail; the slider body forms a sliding fit connection with the notch through the slide groove and the slide rail. When a sealing component is used, the sealing component is also provided with an assembly slide groove that slides and engages with the slide rail; the sealing component forms a sliding fit connection with the slide rail on the notch through the assembly slide groove.

[0014] Furthermore, the aforementioned mounting reference post is provided with weight-reducing grooves. The weight-reducing grooves are configured as follows: multiple weight-reducing grooves extending along the axis of the mounting reference post are distributed circumferentially around the end face of the mounting reference post facing the rear cover.

[0015] Furthermore, the aforementioned rear cover is provided with a stop ring that snaps into the cover and forms a tight fit with the inner circumferential wall of the cover; the circumferential wall of the stop ring is provided with a wave-shaped clamping part; the crest of the wave-shaped clamping part forms a transition fit with the circumferential surface of the cover, and the trough of the wave-shaped clamping part forms a gap fit with the circumferential surface of the cover.

[0016] This utility model has positive effects: (1) The concentrated winding servo motor of this utility model replaces the inner rotor structure with the outer rotor structure. Under the same torque, taking 5NM as an example, the stator core length can be shortened by 26%, which greatly reduces the axial dimension of the motor. At the same time, due to the increase in the area of ​​the magnet, the tooth cogging torque increases. By optimizing the unequal air gap matching method, the tooth cogging torque is weakened, and the harmonic content of the air gap magnetic flux density is weakened.

[0017] (2) This utility model forms a protective space by the cooperation of the cover on the base and the rear cover, which effectively protects the rotor assembly and the stator assembly, and makes the protection level reach IP65 or above.

[0018] (3) In this utility model, the position feedback permanent magnet disc is installed at the connecting end of the rotating shaft, and its installation height does not exceed the end face of the rotor body with the reference through hole, which can further reduce the axial dimension of the motor.

[0019] (4) This utility model uses the design of the hook slider and the notch to make the stator winding output position can be realized by assembly. At the same time, the magnetic encoder lead wire can be positioned and routed by the hook. The design is ingenious.

[0020] (5) This utility model can effectively reduce the overall weight of the motor through the weight reduction groove. Attached Figure Description

[0021] To make the content of this utility model easier to understand, the present utility model will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein... Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a cross-sectional view of the present invention; Figure 3 This is an exploded view of the present invention; Figure 4 This is a schematic diagram of the stator body in this utility model; Figure 5 This is a schematic diagram of the structure of the base in this utility model; Figure 6 for Figure 1 Enlarged view of point A in the middle; Figure 7 This is a schematic diagram of the structure of the centerline hook slider of this utility model.

[0022] Figure 8 This is a partially enlarged view of the stop ring of the rear cover in this utility model.

[0023] In the diagram, the components are: base 1, mounting reference column 11, cover 12, wire threading notch 13, sealing component 14, center through hole 111, weight reduction groove 112, notch 121, stator assembly 2, stator body 21, stator winding 22, stator core 211, injection molded frame 212, tooth crown 2111, outer rotor assembly 3, magnet 31, rotor body 32, shaft 4, rear cover 5, wire outlet 51, stop ring 52, wave-shaped clamping part 521, position feedback permanent magnet assembly 6, permanent magnet bushing 61, position feedback permanent magnet disc 62, magnetic encoder 7, protective cover plate 8, wire hook slider 9, slider body 91, wire hook 92, and slide groove 911. Detailed Implementation

[0024] See Figures 1 to 8 This utility model comprises a base 1, a stator assembly 2, and an outer rotor assembly 3. The stator assembly 2 includes a stator body 21 and stator windings 22 wound around the stator body. The stator body 21 includes a stator core 211 formed by stacking multiple stator laminations of the same shape along the axis of the stator core, and an injection-molded frame 212 that encapsulates the stator core 211 into a single piece. The outer rotor assembly 3 includes a rotor body 32 with magnets 31 fixedly mounted on it. The steel 31 is coaxially arranged with the stator winding 22, and the magnet 31 is located outside the stator winding 22; the stator core 211 formed by stacking includes an annular stator yoke, and multiple stator teeth are distributed circumferentially on the stator yoke; the end of the stator tooth away from the stator yoke is the tooth crown 2111; the end face of the tooth crown 2111 facing the magnet 31 on the rotor body 32 is a variable diameter curved surface; the stator teeth with the variable diameter curved surface form an unequal air gap fit with the magnet 31 on the rotor body 32.

[0025] The base 1 includes a mounting reference column 11 and a cover 12; the stator body 21 is fixedly mounted on the mounting reference column 11; the mounting reference column 11 is provided with a central through hole 111; a bearing mounting seat is provided in the central through hole 111; a rotating shaft 4 is fixedly provided at the rotation center of the rotor body 32; the rotating shaft 4 is rotatably connected to the mounting reference column 11 through a bearing assembled in the bearing mounting seat; the end of the rotating shaft 4 that is not connected to the rotor body 32 passes through the central through hole 111 to form an output end; It also includes a rear cover 5; the rear cover 5 is fixedly connected to the open end of the cover 12; the rear cover 5 and the cover 12 form a protective space; the stator assembly 2 and the rotor assembly 3 are located within the protective space. This protective space can effectively protect the rotor assembly 3 and the stator assembly 2, thereby allowing the motor to adopt a closed design, so that the protection level can reach IP65 or higher.

[0026] The rotor body 32 has a reference through hole at its rotation center; one end of the rotating shaft 4, which is fixedly connected to the rotor body 32, is fixedly disposed in the reference through hole; the end of the rotating shaft 4, which is fixedly connected to the rotor body 32, is a connecting end; a first mounting groove is provided on the end face of the connecting end of the rotating shaft 4; a position feedback permanent magnet assembly 6 is fixedly disposed in the first mounting groove; the position feedback permanent magnet assembly 6 includes a permanent magnet bushing 61 and a position feedback permanent magnet disc 62; the permanent magnet bushing 61 is fixedly installed in the first mounting groove, and its fixed installation method can be adhesive or screw fixing; a second mounting groove is provided on the permanent magnet bushing 61, which is coaxially disposed with the rotating shaft 4; the opening of the second mounting groove faces the rear cover 5; the position feedback permanent magnet disc 62 is fixedly connected in the second mounting groove, and the installation height after installation does not exceed the end face of the rotor body 32 where the reference through hole is provided; a magnetic encoder 7, which is adapted to the position feedback permanent magnet assembly 6 and is used to sense the rotation angle and speed of the rotating shaft, is fixedly installed on the rear cover 5.

[0027] The rear cover 5 has an installation space for installing a magnetic encoder 7; the installation space has an opening that communicates with the outside; and the opening is fitted with a protective cover plate 8 for closing the opening.

[0028] The mounting space for installing the magnetic encoder 7 is directly opposite the connection end of the rotating shaft 4.

[0029] It also includes a hook slider 9; the hook slider 9 includes a slider body 91 and a hook 92 integral with the slider body; the circumferential surface of the cover 12 is provided with a notch 121 extending from the end of the cover 12 facing the rear cover 5 towards the output end of the rotating shaft 4; the notch 121 forms an open insertion port on the end face of the cover 12 facing the rear cover 5; the slider body 91 of the hook slider 9 is inserted into the open insertion port of the notch 121, and the slider body 91 and the notch 121 form a sliding fit; after the rear cover 5 is fixedly connected to the cover 12, it closes the open insertion port of the notch 121 and the hook slider 9 is closed. The wire hook 92 is located outside the cover 12 after being assembled into the notch 121 and the slider 91 is fitted into the notch 121. The slider body 91 and the notch 121 cooperate to form a wire-passing notch 13 through which the lead wire of the stator winding 22 can pass. The lead wire of the stator winding 22 passes through the wire-passing notch 13. The wire-passing notch 13 is sealed by applying glue after the lead wire of the stator winding 22 passes through, or a sealing member 14 is fixedly installed at the wire-passing notch 13 to allow the lead wire to pass through and to seal the wire-passing notch 13. In this embodiment, the sealing member 14 is set at the wire-passing notch 13.

[0030] After the rear cover 5 is fixedly connected to the protective cover plate 8, it forms an outlet 51 through which the lead wire of the magnetic encoder 7 can pass; the lead wire of the magnetic encoder 7 passes through the outlet 51; the outlet 51 is sealed by applying glue after the lead wire of the magnetic encoder 7 passes through; the lead wire of the magnetic encoder 7 passes through the wire hook 92 and is restricted by the wire hook 92 to form a positioning wire.

[0031] The inner wall of the notch 121 is provided with a slide rail extending along its extension direction; the slider body 91 is provided with a slide groove 911 that slides with the slide rail; the slider body 91 forms a sliding connection with the notch 121 through the slide groove 911 and the slide rail sliding with each other.

[0032] In this embodiment, the sealing component 14 is fixedly connected to the wire-threading notch 13 in the following manner: The sealing component 14 is also provided with an assembly groove that slides with the slide rail; before installing the back cover 5, the sealing component 14 is first slidably fitted with the slide rail on the notch 121 through the assembly groove (this sliding fit and the sliding fit of the upper groove 911 with the slide rail are the same, both restricting its sliding direction to be movable, but not detached from the slide rail); then the slider body 91 and the back cover 5 are installed in sequence.

[0033] Before installing the sealing component 14, the lead wire can be passed through the wire hole on the sealing component 14.

[0034] Of course, in other embodiments, the sealing component 14 can also be fixed and installed in other ways, such as by adhesive or by tightening with fixing bolts.

[0035] The mounting reference post 11 is provided with a weight reduction groove 112. The weight reduction groove 112 is configured such that multiple weight reduction grooves extending along the axis are distributed circumferentially around the axis of the mounting reference post 11 on the end face of the mounting reference post 11 facing the rear cover 5.

[0036] The rear cover 5 is provided with a stop ring 52 that fits into the cover 12 and forms a tight fit with the inner circumferential wall of the cover 12; the circumferential wall of the stop ring 52 is provided with a wave-shaped clamping part 521; the crest of the wave-shaped clamping part 521 forms a transition fit with the circumferential surface of the cover 12, and the trough of the wave-shaped clamping part 521 forms a gap fit with the circumferential surface of the cover 12.

[0037] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above descriptions are merely specific embodiments of this utility model and are not intended to limit this utility model. 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 low-speed, high-torque, high-protection external rotor servo motor, comprising a frame, a stator assembly, and an external rotor assembly; the stator assembly includes a stator body and stator windings wound on the stator body; the stator body includes a stator core formed by stacking multiple stator laminations of the same shape along the axis of the stator core, and an injection-molded frame that encapsulates the stator core into a single piece; the external rotor assembly includes a rotor body with magnets fixedly mounted thereon; the magnets are coaxially arranged with the stator windings, and the magnets are located outside the stator windings; characterized in that: The stator core formed by stacking includes an annular stator yoke, on which multiple stator teeth are distributed circumferentially; the end of the stator teeth away from the stator yoke is the tooth crown; the end face of the tooth crown facing the magnet on the rotor body is a variable diameter curved surface; the stator teeth and the magnet on the rotor body form an unequal air gap fit through the variable diameter curved surface. The base includes a mounting reference column and a cover; the stator body is fixedly mounted on the mounting reference column; the mounting reference column has a central through hole; a bearing mounting seat is provided in the central through hole; a rotating shaft is fixedly provided at the rotation center of the rotor body; the rotating shaft is rotatably connected to the mounting reference column through a bearing assembled in the bearing mounting seat; the end of the rotating shaft that is not connected to the rotor body passes through the central through hole to form an output end; It also includes a rear cover; the rear cover is fixedly connected to the open end of the cover; the rear cover and the cover form a protective space; the stator assembly and the rotor assembly are located within the protective space.

2. The low-speed, high-torque, high-protection external rotor servo motor according to claim 1, characterized in that: The rotor body has a reference through hole at its rotation center; one end of the rotating shaft is fixedly connected to the rotor body and is fixedly disposed in the reference through hole; the end of the rotating shaft is fixedly connected to the rotor body as a connecting end; a first mounting groove is provided on the end face of the connecting end of the rotating shaft; a position feedback permanent magnet assembly is fixedly disposed in the first mounting groove; the position feedback permanent magnet assembly includes a permanent magnet bushing and a position feedback permanent magnet disc; the permanent magnet bushing is fixedly installed in the first mounting groove; a second mounting groove is provided on the permanent magnet bushing and is coaxially disposed with the rotating shaft; the opening of the second mounting groove faces the rear cover; the position feedback permanent magnet disc is fixedly connected in the second mounting groove, and the installation height after installation does not exceed the end face of the rotor body with the reference through hole; a magnetic encoder adapted to the position feedback permanent magnet assembly is fixedly installed on the rear cover.

3. The low-speed, high-torque, high-protection external rotor servo motor according to claim 2, characterized in that: The rear cover has an installation space for installing a magnetic encoder; the installation space has an opening that communicates with the outside; and the opening is fitted with a protective cover for closing the opening.

4. A low-speed, high-torque, high-protection external rotor servo motor according to claim 3, characterized in that: The mounting space for installing the magnetic encoder is directly opposite the connection end of the rotating shaft.

5. A low-speed, high-torque, high-protection external rotor servo motor according to claim 3, characterized in that: It also includes a hook slider; the hook slider includes a slider body and a hook integral with the slider body; The casing has a notch extending from the end of the casing facing the rear cover towards the output end of the rotating shaft on its circumferential surface. This notch forms an open insertion port on the end of the casing facing the rear cover. The slider of the hook-slider is inserted into the open insertion port of the notch, and the slider body slides into the notch. After the rear cover is fixedly connected to the casing, it closes the open insertion port of the notch and confines the hook-slider within the notch. After the hook-slider is assembled within the notch, the hook is located outside the casing. The slider body, in conjunction with the notch, forms a threading notch through which the stator winding lead wires can pass. The stator winding lead wires pass through the threading notch. After the stator winding lead wires pass through, the threading notch is sealed by applying adhesive, or a sealing element is fixedly installed at the threading notch to allow the lead wires to pass through and to seal the threading notch. After the rear cover and the protective cover plate are fixedly connected, an outlet is formed for the lead wire of the magnetic encoder to pass through; the lead wire of the magnetic encoder passes through the outlet; the outlet is sealed by applying glue after the lead wire of the magnetic encoder passes through; the lead wire of the magnetic encoder passes through the wire hook and is restricted by the wire hook.

6. A low-speed, high-torque, high-protection external rotor servo motor according to claim 5, characterized in that: The inner wall of the notch is provided with a slide rail extending along its extension direction; the slider body is provided with a slide groove that slides in cooperation with the slide rail; the slider body forms a sliding connection with the notch through the sliding groove and the slide rail. When a sealing component is used, the sealing component is also provided with an assembly groove that slides with the slide rail; the sealing component forms a sliding fit connection with the slide rail on the notch through the assembly groove.

7. A low-speed, high-torque, high-protection external rotor servo motor according to claim 1, 2, 3, 4, 5, or 6, characterized in that: The mounting reference column is equipped with a weight-reducing groove.

8. A low-speed, high-torque, high-protection external rotor servo motor according to claim 1, 2, 3, 4, 5, or 6, characterized in that: The rear cover is provided with a stop ring that fits into the cover and forms a tight fit with the inner circumference of the cover; the circumferential wall of the stop ring is provided with a wave-shaped clamping part; the crest of the wave-shaped clamping part forms a transition fit with the circumferential surface of the cover, and the trough of the wave-shaped clamping part forms a gap fit with the circumferential surface of the cover.

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