Permanent magnet DC motor and positioning mechanism

Abstract

The application relates to a permanent magnet DC motor and a positioning mechanism, which comprises a base, a permanent magnet motor fixedly arranged in the base, a rotating shaft coaxially arranged in the center of the permanent magnet motor, a rear cover fixed to the axial first end of the base, a front cover fixed to the axial second end of the base, a center positioning mechanism arranged between the rotating shaft and the front cover and the rear cover and used for restraining the radial deviation of the rotating shaft and inhibiting the rotary shaking, the center positioning mechanism comprising a mounting ring coaxially fixed to the inner side of the rear cover and a plurality of groups of sensing pieces uniformly distributed on the inner side of the mounting ring, the sensing pieces each comprising a liquid storage bag, an elastic gasket, a flow pipe, a transfer cylinder and a movable plug, the liquid storage bag being fixed to the inner side wall of the mounting ring, and the elastic gasket being fixedly attached to the side end face of the liquid storage bag facing the rotating shaft. The application realizes the beneficial effect of the passive self-adaptive closed-loop adjustment of the radial deviation of the rotating shaft, the structure triggers the action by the deviation of the rotating shaft itself, can accurately restrain the radial jumping of the rotating shaft in real time, inhibits the rotary shaking, and improves the rotation stability of the shaft system.

Description

Technical Field

[0001] This invention relates to the field of motor technology, specifically to a permanent magnet DC motor and a positioning mechanism. Background Technology

[0002] Permanent magnet DC motors possess outstanding advantages such as wide speed range, fast dynamic response, and high energy conversion efficiency, making them core power components in fields such as precision transmission in industrial automation, actuators in medical devices, high-end instruments and equipment, and supporting systems for new energy vehicles. Among these components, the shaft centering and positioning mechanism adapted to the permanent magnet DC motor is a core functional component that ensures the stable coaxial rotation of the motor shaft and suppresses radial offset and rotational vibration. Its centering accuracy, response performance, and operational stability directly determine the motor's output rotation accuracy, vibration and noise level, and operational reliability throughout its entire life cycle. In high-precision applications, extremely high requirements are placed on the adaptive adjustment capability and real-time anti-offset and vibration suppression performance of the centering mechanism.

[0003] Currently, most permanent magnet DC motors use double sets of rigid rolling bearings as the core support unit. The radial offset of the shaft is limited by the fixed radial constraint of the bearings. Some solutions compensate for the wear clearance of the bearings by adding a fixed preload structure.

[0004] Existing permanent magnet DC motors can only provide constant radial support stiffness during operation, making it difficult to achieve passive adaptive closed-loop adjustment triggered by the shaft's own offset. They cannot dynamically reverse the radial runout and rotational jitter that occur in real time, and it is difficult to accurately constrain the radial offset of the shaft in real time. This results in insufficient rotational stability of the shaft system, and after long-term operation, it is prone to problems such as accelerated bearing wear and rapid decay of centering accuracy. They cannot meet the requirements for long-term stable operation of motors in high-precision scenarios. Summary of the Invention

[0005] The purpose of this invention is to provide a permanent magnet DC motor and positioning mechanism, which aims to improve the problem in the prior art that it is difficult to dynamically reverse the radial runout and rotational jitter that occur in real time on the rotating shaft.

[0006] The objective of this invention is achieved through the following technical solution: a permanent magnet DC motor and a positioning mechanism, comprising a base, a permanent magnet motor fixedly disposed within the base, a rotating shaft coaxially passing through the center of the permanent magnet motor, a rear cover fixed at the first axial end of the base, a front cover fixed at the second axial end, and a centering and positioning mechanism for constraining radial offset of the rotating shaft and suppressing rotational jitter is provided between the rotating shaft and the front and rear covers.

[0007] The centering and positioning mechanism includes a mounting ring coaxially fixed to the inner side of the rear end cover, and multiple sets of sensors evenly distributed circumferentially on the inner side of the mounting ring. Each sensing element includes a reservoir, an elastic gasket, a flow tube, a transfer cylinder, and a movable plug. The reservoir is fixed to the inner wall of the mounting ring, the elastic gasket is fitted and fixed to the end face of the reservoir facing the rotating shaft, the inlet end of the flow tube is sealed and connected to the inner cavity of the reservoir, the outlet end of the flow tube is sealed and connected to the inner cavity of the transfer cylinder, the movable plug is slidably sealed in the inner cavity of the transfer cylinder, and the extended end of the movable plug is connected to the leveling component for transmission.

[0008] As a further description of the above technical solution: The centering and positioning mechanism also includes a ball bearing coaxially fixed to the front end of the rotating shaft, a fixing ring coaxially sleeved on the outside of the rotating shaft, and multiple sets of leveling components evenly distributed circumferentially between the mounting ring and the ball bearing. The ball bearing includes an inner ring that is interference-fitted with the shaft, an outer ring that is interference-fitted with the fixed ring, multiple magnetic steel balls, and a connecting collar. The outer circular surface of the inner ring and the inner circular surface of the outer ring are both provided with coaxially arranged annular tracks. The magnetic steel balls are rolled in the closed raceway formed by the two annular tracks. The connecting collar is coaxially sleeved between the inner ring and the outer ring. The connecting collar is provided with limiting holes corresponding to the magnetic steel balls, and the magnetic steel balls are embedded in the limiting holes one by one. The inner and outer rings of the ball bearing are coaxially arranged. The cross section of the annular track is an arc shape that matches the outer diameter of the magnetic steel ball. The magnetic steel balls are evenly distributed along the circumference. The magnetization direction of two adjacent magnetic steel balls is the same. The connecting collar is an annular part made of high-temperature resistant nylon. The diameter of the limiting hole is larger than the outer diameter of the magnetic steel ball and smaller than the groove width of the annular track. As a further description of the above technical solution: The leveling components all include guide tubes, telescopic airbags, pressure plates, conical magnetic blocks, reset springs, and repulsive magnetic plates; The guide tube is fixed radially to the inner wall of the front end cover. The telescopic airbag is sealed at the bottom of the inner cavity of the guide tube. The inner cavity of the telescopic airbag is sealed and connected to the flow tube of the corresponding sensing element. The pressure plate is slidably disposed in the guide tube and is fixed to the outer end face of the telescopic airbag. The conical magnetic block is fixed to the outer end face of the pressure plate. The repulsive magnetic plate is fixed to the outer wall of the fixing ring and is disposed opposite to the conical magnetic block with the same pole. The reset spring is sleeved on the outer side of the conical magnetic block. The two ends of the reset spring abut against the inner wall of the port of the pressure plate and the guide tube, respectively. As a further description of the above technical solution: The mounting ring is a circular ring structure coaxial with the rotating shaft. The number of sensing elements is the same as the number of leveling elements and corresponds one-to-one. The liquid storage bladder is an arc-shaped bladder. Multiple sets of liquid storage bladders are evenly spliced ​​together in a closed-loop structure along the inner circumference of the mounting ring. The elastic gasket is an arc-shaped wear-resistant gasket that matches the end face of the liquid storage bladder. The central rotating cylinder is fixed to the inner side wall of the rear end cover. The extended end of the movable plug passes through the central rotating cylinder and is connected to the telescopic air bladder pipeline of the corresponding leveling element. As a further description of the above technical solution: The permanent magnet motor includes a housing, a stator fixed to the inner wall of the housing, a rotor coaxially disposed inside the stator, a winding assembly wound on the rotor, and a commutator coaxially fixed to the rotating shaft. The rear cover includes a rear end cover fixedly connected to the base, and the rear end cover is provided with a terminal block, a brush holder and a graphite brush that slides in contact with the commutator. The front cover includes a front end cover fixedly connected to the base, and a cooling fan fixedly connected to the rotating shaft is provided on the front end cover. As a further description of the above technical solution: The rear centering and positioning mechanism is axially positioned on the axial rear side of the graphite brush and brush holder. The maximum outer diameter of the mounting ring is smaller than the inner diameter of the commutator. The radial projection of the mounting ring is completely within the radial side of the commutator and has no radial spatial overlap with the graphite brush and brush holder. As a further description of the above technical solution: The rear end cover is a circular end cover that is coaxially fixed to the base. The terminal block is fixed to the outer end face of the rear end cover. The brush holder is uniformly fixed to the inner end face of the rear end cover along the circumference. The graphite brush is slidably embedded in the brush holder and elastically abuts against the outer circular surface of the commutator. The mounting ring is coaxially fixed in the central groove inside the rear end cover. The mounting ring is coaxially set with the rotating shaft and a radial gap is reserved between it and the outer circular surface of the rotating shaft. As a further description of the above technical solution: The housing is a cylindrical structure and is interference-fitted with the inner wall of the base. The stator is a tile-shaped permanent magnet and is uniformly fixed along the inner circumference of the housing. The rotor is a cylindrical iron core made of stacked silicon steel sheets and is interference-fitted with the shaft. The winding group is embedded in the iron core slot of the rotor. The output end of the winding group is electrically connected to the commutator segments of the commutator one by one. The commutator is interference-fitted and fixed on the shaft and located between the rotor and the rear cover. As a further description of the above technical solution: The front end cover is a circular end cover that is coaxially fixed to the base. The center of the front end cover has a through hole for the rotating shaft to pass through. The fixing ring is coaxially embedded in the inner mounting groove of the front end cover. The cooling fan includes a hub that is interference-fitted with the front end of the rotating shaft, and multiple fan blades that are evenly distributed circumferentially on the outside of the hub. The axial projection of the fan blades covers the outer end face of the front main centering assembly.

[0009] Compared with the prior art, the advantages of the present invention are as follows: 1. Through the hydraulic and magnetic repulsion linkage closed-loop structure formed by the uniformly distributed circumferential sensing elements at the rear end, the sealed flow pipeline, and the corresponding leveling elements at the front end, the elastic gasket is deformed under pressure to squeeze the liquid storage bladder. The medium in the liquid storage bladder flows into the transfer cylinder through the flow pipeline. The medium pushes the movable plug to extend axially. The hydraulic force is transmitted to the telescopic air bladder to make it expand. The air bladder pushes the pressure plate and the conical magnetic block to move radially. This full-process linkage action realizes the beneficial effect of passive adaptive closed-loop adjustment of the radial offset of the rotating shaft. This structure relies on the offset of the rotating shaft itself to trigger the action, which can constrain the radial runout of the rotating shaft in real time and suppress rotational jitter, thereby improving the rotational stability of the shaft system.

[0010] 2. Through the structure of a ball bearing with magnetic steel balls fixed coaxially with the rotating shaft, an mounting ring and sensing element arranged axially on the rear side of the carbon brush, the inner ring that rotates with the shaft, the stationary outer ring, and the connecting collar with limiting holes are driven to cooperate synchronously. With the mutual repulsion and limiting action of the magnetic steel balls with the same polarity, the beneficial effects of stable centering of the motor shaft system throughout its entire life cycle and greatly improved operation and maintenance convenience are achieved. This structure can avoid steel ball collision jamming and abnormal wear. The rear structure completely avoids the carbon brush installation space. Maintenance of carbon brushes does not require disassembly of the centering mechanism, reducing operation and maintenance costs and extending the service life of the motor. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the main body of an embodiment of a permanent magnet DC motor and positioning mechanism proposed in this invention; Figure 2 This is a schematic diagram of the permanent magnet motor structure of the permanent magnet DC motor and positioning mechanism proposed in this invention; Figure 3 This is a schematic diagram of the front cover of a permanent magnet DC motor and positioning mechanism proposed in this invention; Figure 4 This is a schematic diagram of the structure of the rear cover of a permanent magnet DC motor and positioning mechanism proposed in this invention; Figure 5 This is a schematic diagram of the centering and positioning mechanism of a permanent magnet DC motor and positioning mechanism proposed in this invention; Figure 6 This is a schematic diagram of the sensing element of a permanent magnet DC motor and positioning mechanism proposed in this invention; Figure 7 This is a schematic diagram of the ball bearing structure of a permanent magnet DC motor and positioning mechanism proposed in this invention; Figure 8 This is a schematic diagram of the leveling component of a permanent magnet DC motor and positioning mechanism proposed in this invention; Figure 9 for Figure 8 Enlarged view of point A in the middle.

[0012] Labeling Explanation: 1. Frame; 2. Permanent Magnet Motor; 201. Housing; 202. Stator; 203. Rotor; 204. Winding Assembly; 205. Commutator; 3. Shaft; 4. Rear Cover; 401. Rear End Cover; 402. Terminal Block; 403. Brush Holder; 404. Graphite Brush; 5. Front Cover; 501. Front End Cover; 502. Cooling Fan; 6. Centering and Positioning Mechanism; 61. Sensor; 611. Liquid Reservoir; 612. Elastic Pad 613. Flow tube; 614. Transfer cylinder; 615. Movable plug; 62. Fixed ring; 63. Ball bearing; 631. Inner ring; 632. Outer ring; 633. Magnetic steel ball; 634. Connecting collar; 635. Circular track; 64. Mounting ring; 65. Leveling component; 651. Guide tube; 652. Telescopic airbag; 653. Pressure plate; 654. Conical magnetic block; 655. Return spring; 656. Repulsive magnetic plate. Detailed Implementation

[0013] The present invention will now be described in detail with reference to the accompanying drawings and embodiments: like Figures 1 to 9 The diagram shown is an embodiment of a permanent magnet DC motor and positioning mechanism provided by the present invention. The permanent magnet DC motor and positioning mechanism include a base 1, which supports and fixes the main structure of the permanent magnet motor 2, providing a stable mounting reference and external protective support for the motor. The permanent magnet motor 2 is fixedly installed inside the base 1. The permanent magnet motor 2 converts DC electrical energy into rotational mechanical energy, providing the core rotational power output for the entire device. A rotating shaft 3 is coaxially inserted through the center of the permanent magnet motor 2, and the rotating shaft 3 stably transmits the output torque of the rotor 203, providing the motor with... The rotational power provides the core output carrier and provides a precise coaxial mounting reference for each rotating component. The first axial end of the base 1 is fixed with a rear cover 4, which provides closed protection for the rear structure of the motor and provides a stable mounting reference for the rear commutation, wiring and centering components. The second axial end of the base 1 is fixed with a front cover 5, which provides closed protection for the front structure of the motor and provides a stable mounting reference for the front centering support and heat dissipation components. A centering and positioning mechanism 6 is provided between the rotating shaft 3 and the front cover 5 and the rear cover 4 to constrain the radial offset of the rotating shaft 3 and suppress rotational vibration.

[0014] The permanent magnet motor 2 includes a housing 201, a stator 202 fixed to the inner wall of the housing 201, a rotor 203 coaxially disposed inside the stator 202, a winding assembly 204 wound on the rotor 203, and a commutator 205 coaxially fixed to the shaft 3. The housing 201 provides protection for the core components of the stator 202 and rotor 203, and provides a stable mounting reference for the stator 202, forming a closed carrier for the main magnetic circuit of the motor. The housing 201 has a cylindrical structure and is interference-fitted with the inner wall of the base 1. The stator 202 provides a stable constant radial magnetic field, providing the necessary magnetic field environment for the current-carrying winding assembly 204 to generate electromagnetic torque. The stator 202 is a tile-shaped permanent magnet and is uniformly fixed along the inner circumference of the housing 201. The rotor 203 receives the electromagnetic torque. The rotor 203, which is a cylindrical iron core made of stacked silicon steel sheets, is the core carrier for the motor to complete energy conversion. It is the core carrier for the motor to complete energy conversion. The rotor 203 is an interference fit with the rotating shaft 3. After the winding group 204 is filled with current, it generates Ampere force in the magnetic field of stator 202, thereby forming electromagnetic torque to drive the rotor 203 to rotate continuously. The winding group 204 is embedded in the iron core slot of rotor 203. The output end of the winding group 204 is electrically connected to the commutator segment of commutator 205 one by one. Commutator 205 realizes the synchronous commutation of the winding current of rotor 203, ensuring that the electromagnetic torque direction is constant during the rotation of rotor 203. At the same time, it completes the transfer of electrical energy from external power source to rotating winding. Commutator 205 is interference fit fixed on rotating shaft 3 and located between rotor 203 and rear cover 4.

[0015] The rear cover 4 includes a rear end cover 401 fixedly connected to the base 1. The rear end cover 401 achieves a rigid connection with the base 1, providing a precise coaxial mounting reference for rear components such as the terminal block 402, brush holder 403, and mounting ring 64. The rear end cover 401 is provided with the terminal block 402, brush holder 403, and graphite brush 404 that slides in contact with the commutator 205. The rear end cover 401 is a circular end cover coaxially fixed to the base 1. The terminal block 402 achieves a safe conductive connection between the external power supply and the internal circuit of the motor, providing a stable and reliable power input port for the motor. The terminal block 402 is fixed to the outer end face of the rear end cover 401. The brush holder 403 limits and guides the graphite brush 404, providing a precise coaxial mounting reference for the graphite brush 404. 4. Provides a stable mounting reference and elastic sliding support. The brush holder 403 is uniformly fixed to the inner end face of the rear cover 401 along the circumference. The graphite brush 404 realizes the sliding electrical connection between the external static circuit and the rotary commutator 205, ensuring that the current is continuously and stably delivered to the winding group 204 of the rotor 203. The graphite brush 404 is slidably embedded in the brush holder 403 and elastically abuts against the outer circular surface of the commutator 205. The mounting ring 64 realizes the uniform circumferential fixing of multiple sets of sensing elements 61, providing a precise coaxial mounting reference for the rear offset sensing component. The mounting ring 64 is coaxially fixed in the central groove inside the rear cover 401. The mounting ring 64 is coaxially set with the rotating shaft 3 and a radial gap is reserved between it and the outer circular surface of the rotating shaft 3.

[0016] The front cover 5 includes a front end cover 501 fixedly connected to the base 1. The front end cover 501 achieves a rigid connection with the base 1, providing a precise coaxial mounting reference for front-end components such as the rotating shaft 3, ball bearing 63, leveling component 65, and cooling fan 502. The front end cover 501 is equipped with a cooling fan 502 that is coaxially fixedly connected to the rotating shaft 3. The cooling fan 502 generates axial cooling airflow as it rotates synchronously with the rotating shaft 3, forcibly cooling and reducing the temperature of core heat-generating components such as the stator 202 and rotor 203 inside the motor, ensuring stable motor operating temperature. The front end cover 501 is a circular end cover that is coaxially fixedly connected to the base 1. The center of the front end cover 501 has a through hole for the rotating shaft 3 to pass through. The fixing ring 62 realizes the connection between the ball bearing and the rotating shaft 63. The rigid fixing of the outer ring 632 of the bearing 63 provides an installation reference for the repulsive magnetic plate 656, and stably transmits the centering thrust of the leveling component 65 to the rotating shaft 3. The fixing ring 62 is coaxially embedded in the inner mounting groove of the front end cover 501. The cooling fan 502 includes a hub that is interference-fitted with the front end of the rotating shaft 3, and multiple fan blades that are evenly distributed circumferentially on the outer side of the hub. The hub realizes the rigid coaxial connection between the cooling fan 502 and the rotating shaft 3, ensuring that the cooling fan 502 rotates synchronously with the rotating shaft 3, and provides a stable mounting carrier for the fan blades. When the fan blades rotate with the hub, they push the air to form an axial airflow, completing the forced convection exchange of heat inside the motor. The axial projection of the fan blades covers the outer end face of the front main centering component.

[0017] The centering and positioning mechanism 6 includes a mounting ring 64 coaxially fixed to the inner side of the rear end cover 401, and multiple sets of sensors 61 evenly distributed circumferentially on the inner side of the mounting ring 64. The sensors 61 realize real-time sensing and acquisition of the radial offset of the tail end of the rotating shaft 3, and convert the mechanical offset into a hydraulic signal for directional transmission.

[0018] Each sensing element 61 includes a reservoir 611, an elastic gasket 612, a flow tube 613, a transfer cylinder 614, and a movable plug 615. The reservoir 611 achieves sealed storage of non-conductive fluid media, converting the mechanical offset of the rotating shaft 3 into a fluid pressure signal through its own volume change. The reservoir 611 is fixed to the inner wall of the mounting ring 64. The elastic gasket 612 directly receives the offset of the rotating shaft 3, compressing the reservoir 611 through its own elastic deformation, while avoiding direct contact between the rotating shaft 3 and the reservoir 611 to prevent structural wear. The elastic gasket 612 is fitted and fixed to the end face of the reservoir 611 facing the rotating shaft 3. The flow tube 613 achieves sealed communication between the reservoir 611 and the transfer cylinder 614, completing the process. The non-conductive fluid medium and pressure signal are transmitted in a directional and leak-free manner. The inlet end of the flow pipe 613 is sealed and connected to the inner cavity of the reservoir 611, and the outlet end of the flow pipe 613 is sealed and connected to the inner cavity of the transfer cylinder 614. The transfer cylinder 614 receives and guides the fluid pressure, providing a sealed sliding cavity space for the movable plug 615, converting the fluid pressure into a linear displacement of the movable plug 615. The movable plug 615 receives and transmits the fluid pressure, converting the fluid pressure signal into a linear displacement signal through its own axial sliding, completing the stable transmission of the offset to the leveling component 65. The movable plug 615 is slidably sealed in the inner cavity of the transfer cylinder 614, and the extended end of the movable plug 615 is connected to the leveling component 65 through a transmission connection. The mounting ring 64 is a circular structure coaxial with the rotating shaft 3. The number of sensing elements 61 is the same as the number of leveling elements 65 and they correspond one-to-one. The liquid storage bladder 611 is an arc-shaped bladder. Multiple sets of liquid storage bladders 611 are evenly spliced ​​together in a closed-loop structure along the inner circumference of the mounting ring 64. The elastic gasket 612 is an arc-shaped wear-resistant gasket that matches the end face of the liquid storage bladder 611. The intermediate cylinder 614 is fixed to the inner side wall of the rear end cover 401. The extended end of the movable plug 615 passes through the intermediate cylinder 614 and is connected to the telescopic airbag 652 pipeline of the corresponding leveling element 65.

[0019] The centering and positioning mechanism 6 also includes a ball bearing 63 coaxially fixed to the front end of the rotating shaft 3. The ball bearing 63 provides basic radial rotational support for the rotating shaft 3, provides low-friction rotational constraint for the rotating shaft 3, and stably transmits the centering thrust of the leveling component 65. The ball bearing 63 includes an inner ring 631 that is interference-fitted with the rotating shaft 3, an outer ring 632 that is interference-fitted with the fixed ring 62, multiple magnetic steel balls 633, and a connecting collar 634. The inner ring 631 achieves synchronous rotation with the rotating shaft 3 and provides an inner rolling track for the magnetic steel balls 633, thus centering the rotating shaft... The rotational motion of the ball bearing 633 is stably transmitted to the rolling elements. Both the outer surface of the inner ring 631 and the inner surface of the outer ring 632 are provided with coaxially arranged annular tracks 635. The outer ring 632 is rigidly fixed to the fixed ring 62, providing an outer rolling track for the magnetic steel balls 633, forming a static support base for the ball bearing 63. The annular tracks 635 provide matching rolling space for the magnetic steel balls 633, constraining the rolling trajectory of the balls and ensuring the stability and coaxiality of the radial support of the ball bearing 63. The magnetic steel balls 633 achieve the connection between the inner ring 631 and the outer ring 632. The rolling connection between the inner and outer rings 631 and 632 converts sliding friction into rolling friction, reducing the rotational resistance of the shaft 3. Simultaneously, the repulsive property of like poles maintains a uniform circumferential distribution. Magnetic steel balls 633 are rolled within a closed raceway formed by two annular tracks 635. The connecting collar 634 circumferentially limits the magnetic steel balls 633, ensuring uniform circumferential distribution and preventing collisions or jamming, thus ensuring stable operation of the ball bearing 63. The connecting collar 634 is coaxially fitted between the inner ring 631 and the outer ring 632. The 4 has corresponding limiting holes for each of the magnetic steel balls 633. The magnetic steel balls 633 are fitted into the limiting holes one by one. The inner ring 631 and outer ring 632 of the ball bearing 63 are coaxially arranged. The cross section of the annular track 635 is an arc shape that matches the outer diameter of the magnetic steel balls 633. The magnetic steel balls 633 are evenly distributed circumferentially. The magnetization direction of two adjacent magnetic steel balls 633 is the same. The connecting collar 634 is an annular part made of high temperature resistant nylon. The diameter of the limiting hole is larger than the outer diameter of the magnetic steel balls 633 and smaller than the groove width of the annular track 635.

[0020] The centering and positioning mechanism 6 also includes a fixing ring 62 coaxially sleeved on the outside of the rotating shaft 3 and multiple sets of leveling components 65 evenly distributed circumferentially between the mounting ring 64 and the ball bearing 63. The leveling components 65 receive the offset signal transmitted by the sensing element 61, convert the hydraulic signal into a magnetic repulsive centering thrust, and complete the reverse correction of the radial offset of the rotating shaft 3. Each leveling component 65 includes a guide tube 651, a telescopic airbag 652, a pressure plate 653, a conical magnetic block 654, a return spring 655, and a repulsive magnetic plate 656. The guide tube 651 provides support for the pressure plate 653 and the conical magnetic block 654. A radial sliding guide provides a sealed mounting cavity for the telescopic airbag 652 and the return spring 655. The guide tube 651 is radially fixed to the inner wall of the front end cover 501. The telescopic airbag 652 receives and converts fluid pressure. Through its own expansion and contraction, it drives the pressure plate 653 to slide radially, completing the conversion of hydraulic signal to mechanical displacement. The telescopic airbag 652 is sealed at the bottom of the inner cavity of the guide tube 651. The inner cavity of the telescopic airbag 652 is sealed and connected to the flow tube 613 of the corresponding sensing element 61. The pressure plate 653 receives and transmits the thrust of the telescopic airbag 652. The conical magnetic block 654 is provided with an installation and fixing reference, driving the conical magnetic block 654 to complete radial synchronous movement. The pressure plate 653 is slidably set in the guide tube 651 and is fixed to the outer end face of the telescopic airbag 652. The conical magnetic block 654 cooperates with the repulsive magnetic plate 656 to generate magnetic repulsion. The magnitude of the magnetic repulsion is adjusted by the change of the distance between itself and the repulsive magnetic plate 656, providing a reverse thrust for the centering adjustment of the rotating shaft 3. The conical magnetic block 654 is fixed to the outer end face of the pressure plate 653. The repulsive magnetic plate 656 generates magnetic repulsion with the conical magnetic block 654 with the same pole opposite each other. The force is transmitted to the rotating shaft 3 through the fixed ring 62, completing the reverse correction of the radial offset of the rotating shaft 3. The repulsive magnetic plate 656 is fixed to the outer wall of the fixed ring 62 and is set opposite to the conical magnetic block 654 with the same pole. The return spring 655 realizes the elastic reset of the pressure plate 653. When the pressure of the telescopic airbag 652 decreases, it drives the pressure plate 653 and the conical magnetic block 654 to return to the initial position, ensuring that the leveling action is reversible. The return spring 655 is sleeved on the outer side of the conical magnetic block 654, and the two ends of the return spring 655 abut against the inner wall of the port of the pressure plate 653 and the guide tube 651, respectively.

[0021] The rear centering and positioning mechanism 6 is axially positioned on the rear side of the graphite brush 404 and brush holder 403, achieving complete spatial isolation from the graphite brush 404 and brush holder 403. This avoids interference with the disassembly and maintenance of the carbon brush, greatly improving the convenience of motor operation and maintenance. The maximum outer diameter of the mounting ring 64 is smaller than the inner diameter of the commutator 205, and the radial projection of the mounting ring 64 is completely within the radial direction of the commutator 205, with no radial spatial overlap with the graphite brush 404 and brush holder 403.

[0022] Working principle: External power is connected to the device through the terminal block 402 on the rear cover 401. The current is transmitted through the graphite brush 404 in the brush holder 403 to the surface of the commutator 205, which is coaxially fixed to the rotating shaft 3. Then, it is transmitted through the commutator segments of the commutator 205 to the winding group 204 on the iron core of the rotor 203. The current-carrying winding group 204 is in a constant radial magnetic field formed by the permanent magnet of the stator 202 on the inner wall of the housing 201. Under the action of Ampere force, it generates a continuous electromagnetic torque, which drives the rotor 203 to rotate synchronously with the interference fit rotating shaft 3, completing the conversion of DC electrical energy into rotational mechanical energy. During the continuous rotation of the rotating shaft 3, the cooling fan 502, which is coaxially fixed to the rotating shaft 3 at the front end, rotates synchronously with the rotating shaft 3. The rotation of the fan blades generates axial airflow, which dissipates heat and cools the stator 202 and rotor 203 structure inside the motor.

[0023] The ball bearing 63, coaxially fixed to the front end of the rotating shaft 3, provides basic rotational support for the rotating shaft 3. The inner ring 631, which is interference-fitted with the rotating shaft 3, rotates synchronously with the rotating shaft 3, while the outer ring 632, which is interference-fitted with the fixed ring 62, remains stationary with the front end cover 501. The annular track 635 formed by the outer circular surface of the inner ring 631 and the inner circular surface of the outer ring 632 forms a closed raceway. Multiple magnetic steel balls 633 roll synchronously with the rotation of the inner ring 631 within the closed raceway. The connecting collar 634, coaxially sleeved between the inner ring 631 and the outer ring 632, limits each magnetic steel ball 633 circumferentially through its own limiting hole, ensuring that the multiple magnetic steel balls 633 are evenly distributed circumferentially. The mutual repulsion force generated between two adjacent magnetic steel balls 633 with the same polarity further maintains the uniform circumferential spacing of the steel balls, avoiding collisions and jamming between the steel balls, providing stable radial rotational support for the rotating shaft 3, and constraining the basic radial offset of the rotating shaft 3.

[0024] When the rotating shaft 3 experiences radial offset or vibration in any direction during rotation, the tail end of the rotating shaft 3 will press the elastic gasket 612 of the corresponding sensing element 61 in the offset direction. The elastic gasket 612 deforms under pressure, simultaneously pressing the reservoir 611 fixed on the inner wall of the mounting ring 64, reducing the inner volume of the reservoir 611. Under pressure, the non-conductive fluid medium filled inside the reservoir 611 flows in from the inlet end of the flow pipe 613, which is sealed and connected to the inner cavity of the reservoir 611, and is transported through the pipeline of the flow pipe 613 to the inner cavity of the intermediate cylinder 614, which is connected to the outlet end. The fluid medium entering the inner cavity of the intermediate cylinder 614 pushes the movable plug 615, which is slidably sealed inside the intermediate cylinder 614, causing the movable plug 615 to extend outward along the axial direction of the intermediate cylinder 614, completing the hydraulic transmission and conversion of the radial offset of the rotating shaft 3.

[0025] After the movable plug 615 inside the transfer cylinder 614 extends outward, it transmits hydraulic force to the telescopic airbag 652 of the corresponding leveling component 65 through a sealed and connected pipeline. This causes the telescopic airbag 652 to expand under pressure at the bottom of the inner cavity of the guide tube 651. The expanded telescopic airbag 652 pushes the pressure plate 653 attached to its outer end face, causing the pressure plate 653 to slide radially towards the center of the rotating shaft 3 along the guide tube 651. During the sliding process of the pressure plate 653, it drives the conical magnetic block 654 fixed on its outer end face to move synchronously towards the fixed ring 62. The return spring 655 sleeved on the outside of the conical magnetic block 654 is compressed synchronously. The conical magnetic block 654 and the repulsive magnetic plate 656 on the outer wall of the fixed ring 62 are opposite each other with the same pole. The magnetic repulsion between the two increases exponentially as the distance decreases. The generated magnetic repulsion is transmitted to the rotating shaft 3 through the fixed ring 62 and the ball bearing 63, applying a reverse centering thrust to the rotating shaft 3 on the offset side.

[0026] When the rotating shaft 3 returns to its coaxial center position under the action of reverse magnetic repulsion, the squeezing force of the tail end of the rotating shaft 3 on the offset side elastic pad 612 decreases synchronously. The liquid storage bladder 611 gradually restores its original volume under its own elasticity. The fluid medium is drawn back from the central rotating cylinder 614 through the flow pipe 613, which drives the movable plug 615 to retract axially along the central rotating cylinder 614. The pressure in the telescopic air bladder 652 decreases synchronously. Under the action of the return spring 655, the pressure plate 653 slides along the guide pipe 651 away from the center of the rotating shaft 3, which drives the conical magnetic block 654 to retract synchronously. The magnetic repulsion between the conical magnetic block 654 and the repulsive magnetic plate 656 gradually decreases until the rotating shaft 3 returns to the coaxial center position. The elastic pad 612, liquid storage bladder 611, movable plug 615, telescopic air bladder 652, pressure plate 653, and conical magnetic block 654 all return to their initial state, completing one closed-loop centering adjustment. Throughout the continuous rotation of the shaft 3, multiple sets of circumferentially distributed sensors 61 and leveling components 65 continuously constrain the radial offset of the shaft 3 and suppress the vibration during rotation, targeting the radial offset and jitter in different directions of the shaft 3.

Claims

1. A permanent magnet DC motor and positioning mechanism, comprising a base (1), characterized in that: A permanent magnet motor (2) is fixedly installed inside the base (1). A rotating shaft (3) is coaxially inserted through the center of the permanent magnet motor (2). A rear cover (4) is fixed at the first axial end of the base (1), and a front cover (5) is fixed at the second axial end. A centering and positioning mechanism (6) is provided between the rotating shaft (3) and the front cover (5) and the rear cover (4) to constrain the radial offset of the rotating shaft (3) and suppress rotational jitter. The centering and positioning mechanism (6) includes a mounting ring (64) coaxially fixed to the inner side of the rear end cover (401), and multiple sets of sensors (61) evenly distributed circumferentially on the inner side of the mounting ring (64). Each of the sensing elements (61) includes a reservoir (611), an elastic gasket (612), a flow tube (613), a transfer cylinder (614), and a movable plug (615). The reservoir (611) is fixed to the inner wall of the mounting ring (64). The elastic gasket (612) is attached to the end face of the reservoir (611) facing the rotating shaft (3). The inlet end of the flow tube (613) is sealed and connected to the inner cavity of the reservoir (611). The outlet end of the flow tube (613) is sealed and connected to the inner cavity of the transfer cylinder (614). The movable plug (615) is slidably and sealed in the inner cavity of the transfer cylinder (614). The extended end of the movable plug (615) is connected to the leveling element (65) in a transmission connection.

2. The permanent magnet DC motor and positioning mechanism according to claim 1, characterized in that: The centering and positioning mechanism (6) also includes a ball bearing (63) coaxially fixed to the front end of the rotating shaft (3), a fixing ring (62) coaxially sleeved on the outside of the rotating shaft (3), and multiple sets of leveling components (65) evenly distributed circumferentially between the mounting ring (64) and the ball bearing (63). The ball bearing (63) includes an inner ring (631) that is interference-fitted with the rotating shaft (3), an outer ring (632) that is interference-fitted with the fixed ring (62), multiple magnetic steel balls (633), and a connecting collar (634). The outer circular surface of the inner ring (631) and the inner circular surface of the outer ring (632) are both provided with coaxially arranged annular tracks (635). The magnetic steel balls (633) are rolled in the closed raceway formed by the two annular tracks (635). The connecting collar (634) is coaxially sleeved between the inner ring (631) and the outer ring (632). The connecting collar (634) is provided with limiting holes corresponding to the magnetic steel balls (633) one by one. The magnetic steel balls (633) are embedded in the limiting holes one by one. The inner ring (631) and outer ring (632) of the ball bearing (63) are coaxially arranged. The cross section of the annular track (635) is an arc shape that matches the outer diameter of the magnetic steel ball (633). The magnetic steel ball (633) is evenly distributed along the circumference. The magnetization direction of two adjacent magnetic steel balls (633) is the same. The connecting collar (634) is an annular part made of high temperature resistant nylon. The diameter of the limiting hole is larger than the outer diameter of the magnetic steel ball (633) and smaller than the groove width of the annular track (635).

3. The permanent magnet DC motor and positioning mechanism according to claim 2, characterized in that: Each of the leveling components (65) includes a guide tube (651), a telescopic airbag (652), a pressure plate (653), a conical magnetic block (654), a return spring (655), and a repulsive magnetic plate (656). The guide tube (651) is fixed radially to the inner wall of the front end cover (501). The telescopic airbag (652) is sealed at the bottom of the inner cavity of the guide tube (651). The inner cavity of the telescopic airbag (652) is sealed and connected to the flow tube (613) of the corresponding sensing element (61). The pressure plate (653) is slidably disposed in the guide tube (651) and is fixed to the outer end face of the telescopic airbag (652). The conical magnetic block (654) is fixed to the outer end face of the pressure plate (653). The repulsive magnetic plate (656) is fixed to the outer wall of the fixing ring (62) and is disposed opposite to the conical magnetic block (654) with the same pole. The reset spring (655) is sleeved on the outer side of the conical magnetic block (654). The two ends of the reset spring (655) abut against the inner wall of the port of the pressure plate (653) and the guide tube (651), respectively.

4. The permanent magnet DC motor and positioning mechanism according to claim 3, characterized in that: The mounting ring (64) is a circular ring structure coaxial with the rotating shaft (3). The number of sensing elements (61) is consistent with the number of leveling elements (65) and corresponds one-to-one. The liquid storage bladder (611) is an arc-shaped bladder. Multiple sets of liquid storage bladders (611) are evenly spliced ​​into a closed-loop structure along the inner circumference of the mounting ring (64). The elastic gasket (612) is an arc-shaped wear-resistant gasket that matches the end face of the liquid storage bladder (611). The intermediate cylinder (614) is fixed to the inner side wall of the rear end cover (401). The extended end of the movable plug (615) passes through the intermediate cylinder (614) and is connected to the telescopic airbag (652) pipeline of the corresponding leveling element (65).

5. A permanent magnet DC motor and positioning mechanism according to claim 1, characterized in that: The permanent magnet motor (2) includes a housing (201), a stator (202) fixed to the inner wall of the housing (201), a rotor (203) coaxially disposed on the inner side of the stator (202), a winding assembly (204) wound on the rotor (203), and a commutator (205) coaxially fixed to the rotating shaft (3). The rear cover (4) includes a rear end cover (401) fixedly connected to the base (1), and the rear end cover (401) is provided with a terminal block (402), a brush holder (403) and a graphite brush (404) that slides in contact with the commutator (205). The front cover (5) includes a front end cover (501) fixedly connected to the base (1), and a cooling fan (502) is provided on the front end cover (501) and fixedly connected to the rotating shaft (3) on the same axis.

6. A permanent magnet DC motor and positioning mechanism according to claim 5, characterized in that: The rear centering and positioning mechanism (6) is axially positioned on the axial rear side of the graphite brush (404) and brush holder (403). The maximum outer diameter of the mounting ring (64) is smaller than the inner diameter of the commutator (205). The radial projection of the mounting ring (64) is completely within the radial direction of the commutator (205) and has no radial spatial overlap with the graphite brush (404) and brush holder (403).

7. A permanent magnet DC motor and positioning mechanism according to claim 5, characterized in that: The rear end cover (401) is a circular end cover that is coaxially fixed to the base (1). The terminal block (402) is fixed to the outer end face of the rear end cover (401). The brush holder (403) is uniformly fixed to the inner end face of the rear end cover (401) along the circumference. The graphite brush (404) is slidably embedded in the brush holder (403) and elastically abuts against the outer circular surface of the commutator (205). The mounting ring (64) is coaxially fixed in the central groove inside the rear end cover (401). The mounting ring (64) is coaxially set with the rotating shaft (3) and a radial gap is reserved between it and the outer circular surface of the rotating shaft (3).

8. A permanent magnet DC motor and positioning mechanism according to claim 5, characterized in that: The housing (201) is a cylindrical structure and is interference-fitted with the inner wall of the base (1). The stator (202) is a tile-shaped permanent magnet and is uniformly fixed along the inner circumference of the housing (201). The rotor (203) is a cylindrical iron core made of stacked silicon steel sheets and is interference-fitted with the rotating shaft (3). The winding group (204) is embedded in the iron core slot of the rotor (203). The output end of the winding group (204) is electrically connected to the commutator segment of the commutator (205) one by one. The commutator (205) is interference-fitted and fixed on the rotating shaft (3) and located between the rotor (203) and the rear cover (4).

9. A permanent magnet DC motor and positioning mechanism according to claim 5, characterized in that: The front end cover (501) is a circular end cover that is coaxially fixed to the base (1). The center of the front end cover (501) has a through hole for the rotating shaft (3) to pass through. The fixing ring (62) is coaxially embedded in the inner mounting groove of the front end cover (501). The cooling fan (502) includes a hub that is interference-fitted with the front end of the rotating shaft (3) and multiple fan blades that are evenly distributed circumferentially on the outside of the hub. The axial projection of the fan blades covers the outer end face of the front main centering assembly.

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