Brushless servo motor easy to install and debug and sweeping vibration electric toothbrush comprising brushless servo motor

Abstract

The utility model discloses a brushless servo motor easy to install and debug, which comprises a shell, a rotor, a stator and an encoder assembly, and is characterized in that the rotor comprises a rotating shaft and a magnetic ring; the shell comprises a shell and a first end cover; the stator comprises a stator core and a winding; the magnetic ring is an M-pole magnetic ring; the encoder assembly comprises a PCB and a magnetic induction device, the magnetic induction device comprises N groups of Hall sensors, and N is 1 or 2; each group of Hall sensors comprises two Hall sensors, and one Hall sensor rotates 90 degrees around the center line of the rotating shaft to reach the position of the other Hall sensor; each Hall sensor is eccentrically arranged relative to the center line of the rotating shaft, and a gap is formed between each Hall sensor and the magnetic ring in the axial direction of the rotating shaft. According to the utility model, the Hall sensor directly senses the magnetic field of the magnetic ring of the rotor to determine the angular position of the rotor, an independent sensing magnet does not need to be arranged on the rotor, the structure is simple, and the installation process is simplified.

Description

Technical Field

[0001] This utility model belongs to the field of motors, and more specifically, relates to an easy-to-install and debug brushless servo motor and a sweeping electric toothbrush including the same. Background Technology

[0002] With the improvement of residents' living standards and their increasing demands for dental aesthetics and health, the market demand for electric toothbrushes will see significant growth. Therefore, in addition to traditional rotary, sonic, and pulse electric toothbrushes, sweeping electric toothbrushes powered by servo motors have emerged in the past two years. These toothbrushes offer a significantly better brushing experience, but to gain market share more quickly, they need to move towards offering better value for money.

[0003] In existing vibrating electric toothbrushes, the magnetic encoder structure of the servo motor requires a Hall sensor and an additional separate induction magnet outside the magnetic ring of the motor rotor. The magnetic polarity and magnetic field strength of the induction magnet change periodically as the motor rotor runs. The Hall sensor generates an electrical signal based on the magnetic polarity and magnetic field strength. By processing and judging the electrical signal, the angular position can be accurately identified. Therefore, the magnetic field of the additional separate induction magnet after passing through the Hall sensor is relatively pure, and this technology is easy to implement.

[0004] Due to the consistency requirements of mass-produced products, both the encoder's sensing magnet and the motor rotor's magnetic ring are mounted on the motor shaft. Their polarity must be strictly matched. For example, the N pole of the magnetic ring can be aligned with the N pole of the sensing magnet, and the S pole of the magnetic ring with the S pole of the sensing magnet, or vice versa. However, the magnetic pole boundaries must coincide. For mass-produced products, one magnetic pole matching method must be chosen. Each servo motor driver needs to be individually debugged to match the motor body. Installation and debugging are tedious, time-consuming, and labor-intensive. Failure to match will result in reverse motor rotation or commutation logic confusion.

[0005] In addition, the vibration of a sweeping electric toothbrush is relatively large during use, which makes the PCB board and the Hall sensor on the PCB board prone to small-angle rotation. This makes the rotation of the motor rotor unstable, requiring readjustment of the zero position and sweeping angle, resulting in a poor brushing experience. Summary of the Invention

[0006] To address the aforementioned deficiencies or improvement needs of existing technologies, this utility model provides an easy-to-install and debug brushless servo motor and a sweeping electric toothbrush including the same. The Hall sensor is arranged off-axis inside the motor, directly sensing the magnetic field of the rotor's own magnetic ring to determine the rotor's angular position. This eliminates the need for a separate sensing magnet, making the structure simpler, simplifying the installation process, and reducing production costs.

[0007] To achieve the above objectives, according to one aspect of this utility model, an easy-to-install and debug brushless servo motor is provided, characterized in that it includes a housing, a rotor, a stator, and an encoder assembly, wherein:

[0008] The rotor includes a rotating shaft and a magnetic ring, the magnetic ring being fixedly mounted on the rotating shaft, and the rotating shaft being mounted on the housing via a first bearing and a second bearing;

[0009] The housing includes a casing and a first end cap mounted on one end of the casing;

[0010] The stator includes a stator core and a winding. The stator core is fixedly installed on the inner wall of the housing, and the winding is fixedly installed on the stator core so that an electromagnetic field is applied to the magnetic ring after energization, thereby driving the magnetic ring to rotate.

[0011] The magnetic ring is an M-pole magnetic ring and M is an even number;

[0012] The encoder assembly includes a PCB board and a magnetic sensing device. The PCB board is mounted on the first end cover, and the magnetic sensing device is mounted on the PCB board. The magnetic sensing device includes N sets of Hall sensors, where N is 1 or 2.

[0013] Each set of Hall sensors includes two Hall sensors for detecting the rotational position of the magnetic ring, and one Hall sensor rotates 90° around the center line of the rotation axis to reach the position of the other Hall sensor.

[0014] Each of the Hall sensors is eccentrically arranged relative to the center line of the rotating shaft, and there is a distance along the axial direction of the rotating shaft between each of the Hall sensors and the magnetic ring.

[0015] Preferably, the PCB board is fixedly mounted on a washer, the washer having a raised structure, and the first end cap having a recessed structure. The raised structure is inserted into the recessed structure to prevent the PCB board from rotating.

[0016] Preferably, the first end cap and the washer cooperate to clamp the PCB board.

[0017] Preferably, the first end cap is riveted to the housing.

[0018] Preferably, the end of the first end cover away from the housing is provided with a process hole for rotating the first end cover to adjust the installation position of the magnetic induction device.

[0019] Preferably, the PCB board has a first reinforcing plate, a second reinforcing plate, and a flexible circuit board connecting the first reinforcing plate and the second reinforcing plate. The magnetic induction device is mounted on the first reinforcing plate, and the second reinforcing plate is provided with gold fingers.

[0020] Preferably, a receiving groove is provided on the outer side wall of the first end cap to accommodate the flexible circuit board.

[0021] Preferably, the housing further includes a second end cover, which is installed at the end of the housing away from the first end cover. The first bearing and the second bearing are respectively installed on the first end cover and the second end cover, and a preload spring is provided between the inner ring of the second bearing and the magnetic ring.

[0022] Preferably, a positioning sleeve is provided between the magnetic ring and the inner ring of the first bearing.

[0023] According to another aspect of this utility model, a vibrating electric toothbrush is also provided, characterized in that it includes a brush handle, a brush head and the brushless servo motor, wherein the brushless servo motor is installed inside the brush handle, and one end of the shaft of the brushless servo motor extends out of the housing and is connected to the brush head.

[0024] In summary, compared with the prior art, the above-described technical solution conceived by this utility model can achieve the following beneficial effects:

[0025] 1) The present invention provides an easy-to-install and debug brushless servo motor, which eliminates the separate induction magnet set on the motor rotor of the existing brushless servo motor structure. It eliminates the need to match the induction magnet with the magnetic ring of the motor rotor itself for debugging. The Hall sensor is arranged off-axis inside the motor. The Hall sensor directly senses the magnetic field of the magnetic ring of the rotor itself to determine the angular position of the rotor, which makes the structure simpler, the assembly process simpler, and the cost lower.

[0026] 2) The present invention provides an easy-to-install and debug electric toothbrush with a PCB board whose position is restricted by the first end cap and the washer. The PCB board will not loosen during the high-intensity vibration of the electric toothbrush, thus preventing interference with the position signal. The Hall sensor will also not "move" significantly during the sweeping mode of the electric toothbrush, thus ensuring the stability of signal transmission. Attached Figure Description

[0027] Figure 1 This is a three-dimensional schematic diagram of the brushless servo motor in this utility model;

[0028] Figure 2 This is an exploded view of the brushless servo motor in this utility model;

[0029] Figure 3 This is a cross-sectional view of the brushless servo motor in this utility model;

[0030] Figure 4 This is a front view schematic diagram showing the relative positions of the magnetic ring and the Hall sensor in this utility model;

[0031] Figure 5 This is a three-dimensional schematic diagram showing the relative positions of the magnetic ring and the Hall sensor in this utility model;

[0032] Figure 6 and Figure 7 These are schematic diagrams of the PCB board of this utility model from different perspectives;

[0033] Figure 8 This is a schematic diagram showing the disassembled first end cap, gasket, and PCB board in this utility model;

[0034] Figure 9 This is a schematic diagram of the first end cap, gasket, and PCB board assembled together in this utility model;

[0035] Figure 10 This is a three-dimensional schematic diagram of the vibrating electric toothbrush of this utility model. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model. Furthermore, the technical features involved in the various embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other.

[0037] Reference Figures 1-9 A brushless servo motor that is easy to install and debug includes a housing 1, a rotor 2, a stator 3, and an encoder assembly 4, wherein:

[0038] The rotor 2 includes a rotating shaft 21 and a magnetic ring 22. The magnetic ring 22 is fixedly mounted on the rotating shaft 21. The rotating shaft 21 is mounted on the outer casing 1 through a first bearing 5 and a second bearing 6.

[0039] The outer casing 1 includes a housing 11 and a first end cap 12 installed at one end of the housing 11. The first end cap 12 is preferably fixed to the housing 11 by riveting.

[0040] The stator 3 includes a stator core 31 and a winding 32. The stator core 31 is fixedly installed on the inner wall of the housing 11, and the winding 32 is fixedly installed on the stator core 31 so that an electromagnetic field is applied to the magnetic ring 22 after energization, thereby driving the magnetic ring 22 to rotate. The magnetic ring 22 of this invention is the magnetic ring 22 that is built into the rotor 2 of the motor, and it interacts with the winding 32 of the stator 3 to rotate.

[0041] The magnetic ring 22 is an M-pole magnetic ring 22 where M is an even number, so it has M magnetic poles that are centrally symmetrically distributed and have a symmetry plane. If M=2, the magnetic ring 22 has a magnetic pole symmetry plane 23, and the two magnetic poles are symmetrical about this magnetic pole symmetry plane 23, so the magnetic pole symmetry plane 23 is selected as the zero-return reference plane. If M is greater than 2, the magnetic ring 22 has more than one magnetic pole symmetry plane 23, and the M magnetic poles are symmetrical about any magnetic pole symmetry plane 23, so any magnetic pole symmetry plane 23 can be selected as the zero-return reference plane.

[0042] The encoder assembly 4 includes a PCB board 41 and a magnetic sensing device. The PCB board 41 is mounted on the first end cover 12, and the magnetic sensing device is mounted on the PCB board 41. The magnetic sensing device includes N sets of Hall sensors 42, where N is 1 or 2.

[0043] Each set of Hall sensors 42 comprises a pair, i.e., two Hall sensors 42, for detecting the rotational position of the magnetic ring 22. One Hall sensor 42 rotates 90° around the centerline of the shaft 21 to reach the position of the other Hall sensor 42; that is, the physical angle (mechanical angle or mounting angle) between the two Hall sensors 42 is 90°. This arrangement of two Hall sensors at a 90-degree angle is common in certain applications, such as brushless motors used to detect the position of the rotor 2, in order to more accurately detect the rotor's position and speed.

[0044] If N=2, there are four Hall sensors 42, forming two pairs. These four Hall sensors 42 are evenly distributed circumferentially on the PCB board 41. If N=1, it is equivalent to removing two adjacent Hall sensors 42 based on N=2.

[0045] Each of the Hall sensors 42 is eccentrically arranged relative to the center line of the rotating shaft 21, so the Hall sensors 42 are off-axis arranged, and there is a distance between each of the Hall sensors 42 and the magnetic ring 22 along the axial direction of the rotating shaft 21.

[0046] This invention uses a Hall sensor 42 to directly detect the rotational position of the magnetic ring 22 of the rotor 2. It is necessary to consider the influence of the magnetic field generated by the winding 32 on the Hall sensor 42, and the influence of the magnetic field on the Hall sensor 42 when the magnetically conductive motor shaft rotates. These magnetic field influences on the Hall sensor 42 cannot be completely eliminated. Therefore, the magnetic field needs to be designed, and attention must be paid to the installation position of the Hall sensor 42. The goal is to ensure that the Hall sensor 42 is primarily affected by the magnetic field of the magnetic ring 22, and minimally affected by the magnetic fields of the motor shaft and coil winding 32. Furthermore, the weak magnetic fields of the motor shaft and winding 32 should not affect the normal signal transmission of the Hall sensor 42. This ensures that after the servo motor is debugged, the Hall sensor 42 can ultimately measure the position of the magnetic ring 22 normally and accurately.

[0047] This invention preferably employs a slotless brushless servo motor structure (which is also applicable to slotted brushless servo motor structures). The slotless brushless servo motor used in this invention has zero cogging torque, making it a very suitable type of servo drive motor. This results in smoother torque control, more precise position control, and low noise in high-frequency vibration mode.

[0048] Furthermore, the PCB board 41 is fixedly mounted on the washer 7, which has a protruding structure 71, and the first end cap 12 has a recessed structure 121. The protruding structure 71 is inserted into the recessed structure 121 to prevent the PCB board 41 from rotating. The first end cap 12 and the washer 7 preferably cooperate to clamp the PCB board 41, which can further prevent the PCB board 41 from vibrating along the axial direction of the rotating shaft 21.

[0049] Furthermore, a process hole 122 is provided at the end of the first end cover 12 away from the housing 11 for rotating the first end cover 12 to adjust the mounting position of the magnetic induction device. Since some circuit boards may inevitably shift in angle during mass production, the PCB board 41 (and gasket 7) can be slightly rotated clockwise or counterclockwise by twisting the process hole 122 on the first end cover 12. After the position and angle are finely adjusted, the first end cover 12 is then riveted to the housing 11. Because the gasket 7 is inconvenient to twist inside the servo motor, it is only by twisting the exposed first end cover 12, which then drives the gasket 7 and the circuit board to rotate slightly, that the position of the PCB board 41 can be easily adjusted. This eliminates the need to open the first end cover 12 to twist the PCB board 41 and then reinstall the first end cover 12 after adjustment, reducing assembly steps and production costs.

[0050] Furthermore, the PCB board 41 has a first reinforcing plate 411, a second reinforcing plate 412, and a flexible circuit board 413 connecting the first reinforcing plate 411 and the second reinforcing plate 412. The magnetic induction device is mounted on the first reinforcing plate 411, and a gold finger 414 is provided on the second reinforcing plate 412.

[0051] The PCB board 41 of this invention is mounted on the washer 7. The first end cap 12 is clamped and coaxially mounted by the protruding structure 71 on the edge of the washer 7. The first end cap 12 is pressed onto the PCB board 41. The recessed structure 121 of the first end cap 12 cooperates with the protruding structure 71 of the washer 7, so that the position of the PCB board 41 is completely restricted, and there will be no loosening during the high-intensity vibration of the electric toothbrush, which would cause interference to the position signal. The PCB board 41, which is clamped between the washer 7 and the first end cap 12, adopts the form of a flexible circuit board 413 + two reinforcing plates. The Hall sensor 42 installed in the area will not "move" significantly during the sweeping vibration mode, so as to ensure the stability of signal transmission. The PCB board 41 extends outward to the motor through the flexible circuit board 413. The end is the plug structure for inserting the main circuit board of the electric toothbrush. It adopts the form of gold fingers 414 + back reinforcing plate, which facilitates the insertion of the corresponding pin connector and achieves stable electrical transmission.

[0052] Furthermore, a receiving groove 123 is provided on the outer side wall of the first end cap 12 to accommodate the flexible circuit board 413, so as to facilitate the electrical connection of the PCB board 41 to other devices.

[0053] Furthermore, the outer casing 1 also includes a second end cover 13, which is installed at the end of the casing 11 away from the first end cover 12. The first bearing 5 and the second bearing 6 are respectively installed on the first end cover 12 and the second end cover 13. A preload spring 8 is provided between the inner ring of the second bearing 6 and the magnetic ring 22 to prevent axial vibration of the inner ring of the second bearing 6.

[0054] Furthermore, a positioning sleeve 9 is provided between the magnetic ring 22 and the inner ring of the first bearing 5 to facilitate the positioning of other parts on the rotating shaft 21.

[0055] According to another aspect of this utility model, a vibrating electric toothbrush is also provided, including a brush handle 100, a brush head 200 and the brushless servo motor, wherein the brushless servo motor is installed inside the brush handle 100, and one end of the shaft 21 of the brushless servo motor extends out of the outer shell 1 and is connected to the brush head 200.

[0056] The Hall sensor 42 of this invention directly senses the magnetic polarity and magnetic field magnitude of the magnetic ring 22 of the motor to generate a corresponding electrical signal. Accurate angular position identification is achieved through the processing and judgment of this electrical signal. If two Hall sensors 42 are arranged circumferentially at 90° intervals on the PCB board 41, when the vibrating electric toothbrush is turned on, the zero-return reference plane of the magnetic ring 22 (a virtual interface imagined by the user, visible only with special tools) rotates to a position where the 2N Hall sensors 42 are symmetrical about the zero-return reference plane. This process is the zero-return process of the motor rotor 2, that is, the vibrating electric toothbrush head 200 rotates to its initial position before use, and the motor also has a certain holding torque to maintain the rotor 2 at its zero position. When the electric toothbrush is turned on and the vibrating mode is activated, the motor rotor 2 (brush head 200) swings symmetrically clockwise and counterclockwise with the zero-return reference plane of the magnetic ring 22 as its initial position, with a sweeping range of angle α.

[0057] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A brushless servo motor that is easy to install and debug, characterized in that, Includes housing, rotor, stator and encoder assembly, wherein: The rotor includes a rotating shaft and a magnetic ring, the magnetic ring being fixedly mounted on the rotating shaft, and the rotating shaft being mounted on the housing via a first bearing and a second bearing; The housing includes a casing and a first end cap mounted on one end of the casing; The stator includes a stator core and a winding. The stator core is fixedly installed on the inner wall of the housing, and the winding is fixedly installed on the stator core so that an electromagnetic field is applied to the magnetic ring after energization, thereby driving the magnetic ring to rotate. The magnetic ring is an M-pole magnetic ring and M is an even number; The encoder assembly includes a PCB board and a magnetic sensing device. The PCB board is mounted on the first end cover, and the magnetic sensing device is mounted on the PCB board. The magnetic sensing device includes N sets of Hall sensors, where N is 1 or 2. Each set of Hall sensors includes two Hall sensors for detecting the rotational position of the magnetic ring, and one Hall sensor rotates 90° around the center line of the rotation axis to reach the position of the other Hall sensor. Each of the Hall sensors is eccentrically arranged relative to the center line of the rotating shaft, and there is a distance along the axial direction of the rotating shaft between each of the Hall sensors and the magnetic ring.

2. The easy-to-install and debug brushless servo motor according to claim 1, characterized in that, The PCB board is fixedly mounted on the washer, which has a raised structure. The first end cap has a recessed structure, and the raised structure is inserted into the recessed structure to prevent the PCB board from rotating.

3. The easy-to-install and debug brushless servo motor according to claim 2, characterized in that, The first end cap and the gasket cooperate to clamp the PCB board.

4. The easy-to-install and debug brushless servo motor according to claim 1, characterized in that, The first end cap is riveted to the housing.

5. The easy-to-install and debug brushless servo motor according to claim 1, characterized in that, The end of the first end cover away from the housing is provided with a process hole for rotating the first end cover to adjust the installation position of the magnetic induction device.

6. The easy-to-install and debug brushless servo motor according to claim 1, characterized in that, The PCB board has a first reinforcing plate, a second reinforcing plate, and a flexible circuit board connecting the first reinforcing plate and the second reinforcing plate. The magnetic induction device is mounted on the first reinforcing plate, and the second reinforcing plate is provided with gold fingers.

7. The easy-to-install and debug brushless servo motor according to claim 6, characterized in that, The outer side wall of the first end cap is provided with a receiving groove for accommodating the flexible circuit board.

8. The easy-to-install and debug brushless servo motor according to claim 1, characterized in that, The housing also includes a second end cap, which is installed at the end of the housing away from the first end cap. The first bearing and the second bearing are respectively installed on the first end cap and the second end cap, and a preload spring is provided between the inner ring of the second bearing and the magnetic ring.

9. The easy-to-install and debug brushless servo motor according to claim 1, characterized in that, A positioning sleeve is provided between the magnetic ring and the inner ring of the first bearing.

10. A vibrating electric toothbrush, characterized in that, The device includes a brush handle, a brush head, and a brushless servo motor as described in any one of claims 1 to 9, wherein the brushless servo motor is installed inside the brush handle, and one end of the shaft of the brushless servo motor extends out of the housing and is connected to the brush head.

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