Limited angle motor with damping mechanism

Abstract

The utility model discloses a limited angle motor with a damping mechanism, which comprises a stator assembly and a rotor assembly, the stator assembly comprises an annular stator core and a winding coil, and the rotor assembly comprises a rotating shaft and a permanent magnet; the inner side of the stator core is also provided with a damping device, the damping device is fixedly connected with the stator core, and a gap is arranged between the damping device and the permanent magnet to form an annular working air gap. According to the utility model, the static moment of the motor is not reduced, the size of the motor is not increased, the dynamic moment of the motor is reduced, the angular acceleration of the rotating shaft is reduced, and the rotation time of the motor is adjusted and controlled.

Description

Technical Field

[0001] The utility model relates to the field of motors, in particular to a limited-angle motor with a damping mechanism. Background Art

[0002] Currently, limited-angle motors are widely used in various servo systems and control mechanisms, offering advantages such as simple structure, easy control, and high reliability. Limited-angle motors have a variety of principles and structures, most of which use structures similar to traditional brushless DC motors. One type of limited-angle motor uses a toroidal iron core stator. Due to its simple structure and low production cost, it is particularly suitable for applications with no special requirements for torque fluctuations, such as electric switching.

[0003] The limited-angle motor with a circular iron core stator structure has a continuous and uniform working air gap in the shape of a circular ring, and the magnetic flux density in the working air gap is sinusoidally arranged. When power is turned on, the torque of the rotor also fluctuates sinusoidally with the angle. The fluctuation is large, causing the angular acceleration of the limited-angle motor shaft to be too large. The rotation time within the limited angle is very short, and the impact force when hitting the mechanical limit is too large, which can easily cause wear and failure of the mechanical limit. If the motor torque is directly reduced, the motor will be difficult to start because it cannot overcome the static friction torque.

[0004] Therefore, for situations where there is a rotation time limit, how to ensure that the rotation time is within the limit without reducing the static torque of the motor and without significantly increasing the size of the motor becomes a technical problem that needs to be solved. Utility Model Content

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to solve the problems of the existing limited-angle motor, such as small static torque, large torque fluctuation, large angular acceleration of the shaft, fast rotation time, and easy wear and failure of the mechanical limit, and to provide a limited-angle motor with a damping mechanism, which can reduce the dynamic torque of the motor, reduce the angular acceleration of the shaft, and adjust and control the rotation time of the motor without reducing the static torque of the motor and without increasing the volume of the motor.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: a limited-angle motor with a damping mechanism, including a stator assembly and a rotor assembly, the stator assembly including an annular stator core and a winding coil, and the rotor assembly including a rotating shaft and a permanent magnet; characterized in that a damping device is also provided on the inner side of the stator core, the damping device is fixedly connected to the stator core, and a gap is provided between the damping device and the permanent magnet to form an annular working air gap.

[0007] Furthermore, the damping device is annular, and the damping device as a whole is a conductor.

[0008] Furthermore, the damping device is made of metal.

[0009] Furthermore, the metal is copper.

[0010] Furthermore, the winding coil includes an inner coil and an outer coil, and the inner coil and the outer coil are symmetrically distributed on both sides of the stator core.

[0011] Furthermore, coil slots are provided on the inner side and the outer side of the stator core, corresponding to the inner coil and the outer coil, and the inner coil and the outer coil are embedded in the coil slots at corresponding positions.

[0012] Furthermore, the damping device is tightly fitted with the stator core, and the outer wall of the damping device is in contact with the inner plate of the stator core.

[0013] Compared with the existing technology, the present invention has the following advantages: the overall structure is simple, and it can weaken the dynamic torque of the motor, reduce the angular acceleration of the rotating shaft, and adjust and control the rotation time of the motor without reducing the static torque of the motor and significantly increasing the volume of the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural diagram of the present utility model.

[0015] In the figure: 1—stator core, 2—winding coil, 3—rotating shaft, 4—permanent magnet, 5—damping device. DETAILED DESCRIPTION

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0017] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the utility model for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0018] It should be noted that similar reference numerals and letters denote similar items in the following figures. Therefore, once an item is defined in one figure, it does not require further definition or explanation in subsequent figures. In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating positions or relationships, are based on the positions or relationships shown in the figures, or the positions or relationships in which the utility model product is typically placed when in use. These terms are intended solely for ease of description and simplification of the description of the utility model, and do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the utility model. Furthermore, the terms "first," "second," and "third," etc., are used solely to distinguish descriptions and should not be construed as indicating or implying relative importance. Furthermore, terms such as "horizontal" and "vertical" do not imply that a component must be absolutely horizontal or overhanging, but rather may be slightly tilted. For example, "horizontal" simply refers to a direction that is more horizontal than "vertical," and does not imply that the structure must be completely horizontal, but rather may be slightly tilted. It should also be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0019] Example: See Figure 1 A limited-angle motor with a damping mechanism comprises a stator assembly and a rotor assembly. The stator assembly includes an annular stator core 1 and winding coils 2. The rotor assembly includes a rotating shaft 3 and permanent magnets 4 (magnetic steel). The permanent magnets 4 are evenly distributed around the rotating shaft 3 and fixedly connected to the rotating shaft 3 (e.g., by gluing). The rotating shaft 3 is coaxial with the stator core 1. During implementation, the motor also includes a motor end cover, through which the rotating shaft 3 is connected to the stator core 1. The winding coils 2 include an inner coil and an outer coil. Both the inner coil and the outer coil are arranged in an arc shape and are symmetrically distributed on either side of the stator core 1, thereby achieving limited-angle rotation of the rotor assembly. During implementation, coil slots are provided on the inner and outer sides of the stator core 1, corresponding to the inner and outer coils. The inner and outer coils are embedded in the corresponding coil slots.

[0020] A damping device 5 is also provided on the inner side of the stator core 1. This damping device 5 is fixedly connected to the stator core 1, with a gap between the damping device 5 and the permanent magnet 4 forming an annular working air gap. The damping device 5 is annular in shape and is entirely conductive, enabling it to generate induced currents (eddy currents) in a changing magnetic field (when the rotor assembly rotates). Specifically, the damping device 5 is made of metal; preferably, copper, including brass, red copper, etc. The motor's rotation time can be adjusted and controlled by adjusting the axial length and thickness of the damping device 5 as needed. For ease of assembly, the damping device 5 is tightly fitted (interference fit) with the stator core 1, with its outer wall conforming to the inner plate of the stator core 1. Alternatively, the damping device 5 can be fixedly attached to the stator core 1 using adhesive for greater connection stability.

[0021] In this solution, damping device 5 is made of a low-resistivity material to induce eddy currents in a dynamic magnetic field. These eddy currents simultaneously react against the dynamic magnetic field, generating a damping torque that prevents the magnetic field from shifting. This damping torque is in the opposite direction of the motor's driving torque, thereby reducing the driving torque during motor rotation, thereby reducing the angular acceleration of shaft 3 and ultimately achieving the goal of reducing the rotational speed of shaft 3 and increasing the rotational time. Furthermore, since the damping torque is generated only after shaft 3 rotates, no damping torque is generated at the moment the motor shaft starts, as shaft 3 has not yet rotated. Therefore, installing damping device 5 does not reduce the static torque (including starting torque) of the motor. In addition, the damping device 5 is arranged between the stator core 1 and the permanent magnet 4. Since there is a gap between the stator core 1 and the permanent magnet 4, when the thickness of the damping device 5 is relatively low, there is no need to increase the overall volume of the motor; when the thickness of the damping device 5 is relatively large, it is only necessary to make the stator core 1 larger or the permanent magnet 4 smaller, and there is no need to significantly increase the overall volume of the motor.

[0022] During operation, the magnetic lines of force of the permanent magnet 4 originate from the north pole, pass through the working air gap, the damping device 5, and the inner coil, enter the stator core 1, reach the vicinity of the magnet's south pole, then exit the stator core 1, pass through the inner coil, the damping device 5, and the working air gap again, reach the magnet's south pole, and then reach the magnet's north pole, forming a closed loop. During this process, according to the law of electromagnetic induction, when the magnetic flux passing through the closed loop changes, an induced electromotive force is induced in the closed loop. Because it is a closed loop, there must be loop resistance. According to Ohm's law, this induced electromotive force will form a loop current in the closed loop. According to Lenz's law, the magnetic field of this loop current will always oppose the change in the magnetic flux that causes the current change. The damping device 5 is fixed to the stator core 1. Thus, when the rotor rotates counterclockwise, the magnetic flux lines of the rotor magnets also rotate counterclockwise. This increases the magnetic flux through the copper ring's cross-section, generating an induced voltage. This induced voltage generates a clockwise loop current. According to the right-hand rule, the magnetic field of this loop current is directed toward the axis. That is, the inner side of the loop (closer to the axis) is the north pole. Like poles in the magnetic field repel each other, hindering further clockwise rotation and generating a damping torque. Similarly, when the rotor rotates clockwise, the magnetic flux through the copper ring's cross-section decreases, generating a reverse induced voltage and the reverse loop current. The inner side of the loop is the south pole, and opposite poles attract each other, hindering further counterclockwise rotation of the magnetic field and generating a damping torque.

[0023] According to the law of electromagnetic induction, the magnitude of the induced voltage is proportional to the rate of change of the magnetic flux passing through the cross-section. Within the motor, the rate of change of the magnetic flux is proportional to the rotational speed of the rotating shaft 3. The loop current generated by the induced voltage within the damping device 5 is proportional to the electrical conductivity of the damping device 5, the thickness and length of the cross-section of the damping device 5, and the magnetic field density generated by the loop current is proportional to the current. When the rotational speed is constant, to increase the damping torque, it is necessary to increase the magnetic field density of the loop current, that is, to increase the loop current. This can be achieved by reducing the resistivity of the damping device 5 material and increasing the thickness and length of the cross-section of the damping device 5. Among the commonly used materials currently, copper is more suitable for the damping device 5 for economic reasons. After the material is selected, the damping torque can be adjusted by adjusting the thickness and length of the copper ring.

[0024] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Ordinary technicians in this field should understand that those modifications or equivalent replacements of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A limited-angle motor with a damping mechanism, comprising a stator assembly and a rotor assembly, wherein the stator assembly comprises an annular stator core and winding coils, and the rotor assembly comprises a rotating shaft and permanent magnets; characterized in that: A damping device is also provided on the inner side of the stator core. The damping device is fixedly connected to the stator core, and there is a gap between the damping device and the permanent magnet to form an annular working air gap.

2. The limited-angle motor with a damping mechanism according to claim 1, characterized in that: The damping device is annular in shape, and the damping device as a whole is a conductor.

3. The limited-angle motor with a damping mechanism according to claim 1 or 2, characterized in that: The damping device is made of metal.

4. The limited-angle motor with a damping mechanism according to claim 3, characterized in that: The metal is copper.

5. The limited-angle motor with a damping mechanism according to claim 1, characterized in that: The winding coil includes an inner coil and an outer coil, and the inner coil and the outer coil are symmetrically distributed on both sides of the stator core.

6. The limited-angle motor with a damping mechanism according to claim 5, characterized in that: Coil slots are provided on the inner side and the outer side of the stator core, corresponding to the inner coil and the outer coil, and the inner coil and the outer coil are embedded in the coil slots at corresponding positions.

7. The limited-angle motor with a damping mechanism according to claim 1, characterized in that: The damping device is tightly fitted with the stator core, and the outer wall of the damping device is in contact with the inner plate of the stator core.

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