Motor and oral cavity cleaning equipment
By optimizing the magnet distribution and shape structure in the motor of the oral cleaning device, the problems of small motor swing angle and high-frequency vibration were solved, enabling motor operation with a larger swing angle and lower frequency, thus improving the user experience.
Patent Information
- Application Number
- CN202422844273.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2025-11-07
- Estimated Expiration
- 2034-11-20
AI Technical Summary
Existing oral cleaning equipment has a small motor swing angle, which makes it difficult to meet the teeth cleaning needs of different consumers, and the high-frequency vibration causes user discomfort and increased noise.
Design a motor by arranging a first magnet and a second magnet with different polarities on the rotor assembly, optimizing their distribution and shape structure on the stator core, reducing cogging torque, increasing the swing angle of the rotor assembly, and reducing the vibration frequency.
While keeping the motor output torque essentially unchanged, the rotor assembly's swing angle was increased, the vibration frequency was reduced, the user experience was improved, toothache and noise issues were avoided, and the teeth cleaning needs of different consumers were met.
Smart Images
Figure CN223527875U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to oral cavity cleaning equipment technical field, concretely relates to a kind of motor applied to oral cavity cleaning equipment and a kind of oral cavity cleaning equipment. BACKGROUND
[0002] Motor refers to the electromagnetic device that realizes the conversion or transmission of electric energy according to electromagnetic induction law.
[0003] Oral cavity cleaning equipment is to use high-speed vibrating motor shaft to drive brush head swing or vibration to achieve the effect of cleaning teeth. Oral cavity cleaning equipment can produce high-frequency vibration through motor, which can decompose toothpaste into fine foam and clean the gap between teeth deeply. Therefore, oral cavity cleaning equipment has stronger cleaning ability than traditional toothbrush. The vibration frequency of the motor of the current oral cavity cleaning equipment is usually higher than 200 Hz.
[0004] And, the angle of the motor of the current oral cavity cleaning equipment driving the brush head to swing is small, and the angle of swing is generally not more than 10°, which is difficult to meet the tooth cleaning needs of different consumers.
[0005] Therefore, how to provide a motor with a large swing angle applied to oral cavity cleaning equipment has become a technical problem to be solved. SUMMARY
[0006] The utility model provides a kind of motor applied to oral cavity cleaning equipment and a kind of oral cavity cleaning equipment to solve the problem that the swing angle of the current oral cavity cleaning equipment is small, which affects user experience.
[0007] To solve the above technical problems, the utility model provides a kind of motor, the motor includes:
[0008] Stator assembly arranged to generate a magnetic field, wherein the stator assembly includes at least one stator core;
[0009] Rotor assembly arranged at least partially within the magnetic field of the stator assembly, the rotor assembly includes a power shaft and a magnet assembly arranged on the power shaft and cooperating with the stator core; the stator core is configured to drive the rotor assembly to reciprocate at a predetermined angle under energized state;
[0010] Wherein, each magnet assembly is configured to include a first magnet and a second magnet arranged around the circumference of the power shaft and cooperating with the same stator core, the first magnet and the second magnet are spaced apart on the power shaft; and the at least part of the first magnet close to the stator core and the at least part of the second magnet close to the stator core are configured to have different polarities.
[0011] Optionally, the first magnet and the second magnet are both in the shape of a circular arc, including an outer circular arc, an inner circular arc distributed in the radial direction, and two side edges respectively connecting two ends of the outer circular arc and the inner circular arc; the central angles of the outer circular arc and the inner circular arc are the same.
[0012] Optionally, the central angles of the outer circular arc and the inner circular arc are both within a first preset angle range; the first preset angle range is 42° to 57°; the central angle of the first outer circular arc of the first magnet is the same as the central angle of the outer circular arc of the second magnet.
[0013] Optionally, the central angles of the outer circular arc and the inner circular arc are both configured as 49.5°.
[0014] Optionally, the central angles of the outer circular arc and the inner circular arc are both configured as 45°.
[0015] Optionally, the central angles of the outer circular arc and the inner circular arc are both configured as 54°.
[0016] Optionally, the thicknesses of the first magnet and the second magnet are both within a preset thickness range; the preset thickness range is 1 millimeter to 2 millimeters; the thicknesses of the first magnet and the second magnet are the distances of the outer circular arc and the inner circular arc in the radial direction.
[0017] Optionally, the thicknesses of the first magnet and the second magnet are both configured as 1.5 millimeters.
[0018] Optionally, in a plane perpendicular to the rotation axis of the rotor assembly, a second included angle between the center line of the first magnet and the center line of the second magnet is within a second preset included angle range; the second preset included angle range is 73° to 87°; the center line of the first magnet is a line from the center of the first magnet to the rotation axis, and the center line of the second magnet is a line from the center of the second magnet to the rotation axis.
[0019] Optionally, the interval of the first magnet and the second magnet on the power shaft is configured as a third central angle within a third preset included angle range; the third preset included angle range is 23.5° to 38°.
[0020] Optionally, two outer boundaries of the magnet assembly extend to a third included angle formed by the rotation axis of the rotor assembly within a fourth preset included angle range; the fourth preset included angle range is 122° to 141°.
[0021] Optionally, the third included angle is configured as 127°.
[0022] Optionally, the third included angle is configured as 127.5°.
[0023] Optionally, the third included angle is configured as 136°.
[0024] Optionally, the power shaft comprises a mounting groove; the mounting groove is used for mounting the magnet assembly.
[0025] Optionally, the magnets in the magnet assembly are embedded into the mounting groove through an adhesive.
[0026] Optionally, the number of the mounting grooves is 4.
[0027] Optionally, when in the balanced position, the first magnet and the second magnet correspond to two sides of the stator core respectively, and the first magnet and the second magnet overlap with the central projection part of the stator core in the radial direction.
[0028] The ratio of the central angle corresponding to the projection overlap part of the first magnet and the stator core to half of the central angle corresponding to the inner arc of the stator core ranges from 40% to 70%; the ratio of the central angle corresponding to the projection overlap part of the second magnet and the stator core to half of the central angle corresponding to the inner arc of the stator core ranges from 40% to 70%.
[0029] Optionally, the ratio of the central angle corresponding to the projection overlap part of the first magnet and the stator core to the central angle corresponding to the outer arc of the stator core facing the first magnet ranges from 30% to 45%; the ratio of the central angle corresponding to the projection overlap part of the second magnet and the stator core to the central angle corresponding to the outer arc of the stator core facing the second magnet ranges from 30% to 45%.
[0030] Optionally, the motor comprises an electromagnetic coil arranged around the stator core; in response to a control signal applied to the electromagnetic coil, the stator core rotates relative to the rotor assembly around the rotation axis.
[0031] Optionally, the frequency range of the motor in the running state is 100 Hz to 180 Hz.
[0032] Optionally, the width of the air gap between the outer arc of the first magnet and the second magnet and the inner arc of the stator core facing the magnet assembly ranges from 0.15 mm to 0.25 mm.
[0033] Optionally, the stator core is provided with two stator cores which are symmetrically distributed; the magnet assembly is provided with two magnet assemblies; one magnet assembly corresponds to one stator core; and a first included angle between the two magnet assemblies is greater than a third central angle of the interval between the first magnet and the second magnet in the magnet assembly.
[0034] Optionally, at least one plane containing the rotation axis of the rotor assembly is a plane of symmetry;
[0035] The stator core is symmetrically arranged with the plane of symmetry as a reference plane, and / or,
[0036] The first magnet and the second magnet are symmetrically arranged with the plane of symmetry as a reference plane.
[0037] The oral cleaning device provided by the embodiments of the present application also has the motor.
[0038] At least one embodiment of the present application can achieve the following beneficial effects: by arranging the magnet assembly of the motor around the circumference of the power shaft, the first magnet and the second magnet in the magnet assembly, which are configured to have different polarities, can cooperate with the same core, and the first magnet and the second magnet can have a certain interval, so that the magnetic field generated by the rotor assembly is relatively uniform, the cogging torque is reduced, the swing angle of the rotor assembly is increased under the condition that the output torque of the motor is basically unchanged, the driving time of a single cycle of the motor operation is prolonged, and the sweep frequency of the motor is reduced, thereby improving the user experience of using the oral cleaning device with the motor. BRIEF DESCRIPTION OF DRAWINGS
[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiment or prior art description are briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments described in the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.
[0040] Figure 1 A schematic diagram of the internal structure of the motor is provided for the embodiments of the present application;
[0041] Figure 2 A schematic diagram of the overall structure of the motor is provided for the embodiments of the present application;
[0042] Figure 3 A schematic diagram of the magnet structure is provided for the embodiments of the present application;
[0043] Figure 4 A schematic diagram of the central angle structure of the magnet is provided for the embodiments of the present application;
[0044] Figure 5 A structure schematic view of a third central angle of the first magnet and the second magnet spaced on the power shaft is provided for the embodiment of the present specification;
[0045] Figure 6 A structure schematic view of a second included angle is provided for the embodiment of the present specification;
[0046] Figure 7 A structure schematic view of a third included angle is provided for the embodiment of the present specification;
[0047] Figure 8 A structure schematic view of a fourth central angle is provided for the embodiment of the present specification;
[0048] Figure 9 A structure schematic view of a fifth central angle is provided for the embodiment of the present specification;
[0049] Figure 10 A structure schematic view of the power shaft is provided for the embodiment of the present specification;
[0050] Figure 11 A distribution schematic view of simulation data of the motor cogging torque is provided for the embodiment of the present specification;
[0051] Figure 12 A distribution schematic view of simulation data of the motor torque is provided for the embodiment of the present specification.
[0052] The reference signs: 1, stator assembly, 11, stator core, 2, rotor assembly, 21, power shaft; 211, rotor core, 2111, mounting groove, 212, output shaft, 22, magnet assembly, 221, first magnet, 2211, outer arc, 2212, inner arc, 2213, side, 222, second magnet, 223, first central angle, 224, second central angle, 225, third central angle, 226, first included angle, 227, second included angle, 228, third included angle, 229, fourth central angle, 230, fifth central angle, 3, motor housing, 31, limiting piece, 4, air gap, 5, electromagnetic coil. DETAILED DESCRIPTION
[0053] In order to make the purpose, technical scheme and advantages of one or more embodiments of the present specification clearer, the technical scheme of one or more embodiments of the present specification will be described clearly and completely in combination with the specific embodiments of the present specification and corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present specification, not all the embodiments. Based on the embodiments in the present specification, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of one or more embodiments of the present specification.
[0054] The embodiment of the present specification provides an electric machine which can be applied in oral cleaning devices or nursing devices such as electric toothbrushes, and of course can be applied in other electronic devices which need reciprocating swing, and the like, which are not listed one by one here. The electric machine can include a stator assembly which can be arranged to generate a magnetic field, and a rotor assembly which is arranged at least partially in the magnetic field of the stator assembly. The stator assembly includes at least one stator core, and the rotor assembly includes a power shaft and a magnet assembly. The magnet assembly is arranged on the power shaft and cooperates with the stator core. The cooperation between the magnet assembly and the stator core can be that the stator core drives the rotor assembly to reciprocate by a predetermined angle under the energized state.
[0055] Each magnet assembly in the embodiment of the present specification can include a first magnet arranged around the circumference of the power shaft and cooperating with the stator core, and a second magnet. The first magnet close to at least part of the stator core and the second magnet close to at least part of the stator core are configured to have different polarities, and the first magnet and the second magnet can be arranged on the power shaft with a preset central angle interval, so that the magnetic field distribution on the rotor assembly is more uniform, the cogging torque is reduced, so that the swing angle of the rotor assembly is increased under the condition that the output torque of the electric machine is unchanged, the driving time of the electric machine in a single cycle is prolonged, and then the sweep frequency of the electric machine is reduced, and the experience of the user using the oral cleaning device with the electric machine is improved.
[0056] The stator core in the embodiment of the present specification can be fixed on the electric machine body to provide a magnetic field for the electric machine. The stator core can be provided with one, two or more; when the number of stator cores is two or more, the stator cores are usually arranged uniformly in the circumferential direction of the rotor assembly, so as to facilitate the circular rotation or reciprocating swing of the rotor assembly, and the like.
[0057] The power shaft in the embodiment of the present specification can be rotatably connected to the electric machine body through a bearing or the like, so that the power shaft can rotate relative to the electric machine body. The magnets in the rotor assembly arranged circumferentially on the power shaft are configured to have different polarities, which can be that when the end of the first magnet facing the stator core is S pole, the end of the second magnet facing the stator core is N pole; or when the end of the first magnet facing the stator core is N pole, the end of the second magnet facing the stator core is S pole. In this way, when the electromagnetic coil is energized to generate a magnetic field, the magnet assembly can reciprocate by a predetermined angle under the action of the magnetic field, so as to realize the reciprocating swing of the electric machine.
[0058] In existing technologies, the vibration frequency of the motors in oral hygiene devices (such as electric toothbrushes) is typically higher than 200 Hz. On the one hand, high-frequency vibration can negatively impact the user experience for people with sensitive teeth, causing increased toothache and sensitivity. On the other hand, high-frequency vibration increases motor noise, further affecting the user experience. Furthermore, the current motors in oral hygiene devices drive the brush head to oscillate at a relatively small angle, generally not exceeding 10°, which is insufficient to meet the diverse teeth-cleaning needs of different consumers.
[0059] In the motor described in this specification, by optimizing the shape and structure of the first and second magnets and their positions on the rotor core, the cogging torque of the motor can be reduced. This allows for an increase in the swing angle of the rotor assembly while maintaining a substantially constant output torque. When the motor described in this specification is applied to oral hygiene devices such as electric toothbrushes, the increased swing angle of the rotor assembly helps meet the teeth-cleaning needs of different consumers. Furthermore, it can reduce the vibration frequency of the motor, thereby avoiding the increased toothache and sensitivity caused by high-frequency vibration, and also preventing increased motor noise due to high-frequency vibration, thus improving the user experience when using oral hygiene devices equipped with this type of motor.
[0060] The technical solutions provided in the various embodiments of this specification are described in detail below with reference to the accompanying drawings.
[0061] This specification provides an embodiment of a motor used in an oral hygiene device, enabling the device to operate based on the motor, clean teeth and gums, and protect tooth and gum health. Figure 1 This is a schematic diagram of the internal structure of a motor provided as an embodiment of this specification. Figure 1 As shown, the motor may include: a stator assembly 1 arranged to generate a magnetic field, wherein the stator assembly 1 includes at least one stator core 11; and a rotor assembly 2 at least partially arranged within the magnetic field of the stator assembly 1, the rotor assembly 2 including a drive shaft 21 and a magnet assembly 22 disposed on the drive shaft 21 and cooperating with the stator core 11; the stator core 11 is configured to drive the rotor assembly 2 to reciprocate at a predetermined angle when energized.
[0062] Each of the magnet assemblies 22 is configured to include a first magnet 221 and a second magnet 222 arranged circumferentially around the power shaft 21 and cooperating with the same stator core 11, wherein the first magnet 221 and the second magnet 222 are spaced apart on the power shaft 21; and at least a portion of the first magnet 221 near the stator core 11 and at least a portion of the second magnet 222 near the stator core 11 are configured to have different polarities.
[0063] Figure 2 This is a schematic diagram of the overall structure of the motor in the embodiments of this specification. Figure 1 and Figure 2 As shown, the motor may include a stator assembly 1, a rotor assembly 2, and a motor housing 3. The stator assembly 1 is integrally injection molded and embedded in both sides of the motor housing 3, and the rotor assembly 2 is installed inside the motor housing 3. The stator assembly 1 and the rotor assembly 2 are coaxially fitted. The stator assembly 1 does not require secondary manual assembly, resulting in a smaller concentricity tolerance between the stator assembly 1 and the rotor assembly 2. This effectively reduces the cumulative tolerance of the assembled motor, reduces the vibration generated by the rotor assembly 2 during rotation, and lowers the noise during motor operation.
[0064] In the embodiments of this specification, the stator assembly 1 may include one or more pairs of stator cores 11 evenly distributed in the circumferential direction, and electromagnetic coils 5 arranged around the stator cores 11. When the electromagnetic coils 5 are energized, the stator assembly 1 can generate a magnetic field. Specifically, during the energizing process, the stator assembly 1 generates an alternating magnetic field, and by changing the magnetic field, the rotor assembly 2 corresponding to the stator cores 11 is controlled to reciprocate according to the changing frequency of the magnetic field.
[0065] In practical applications, the stator core 11 can be made of high-permeability silicon steel sheets. Silicon steel sheets are an alloy material mainly composed of silicon, carbon, and iron, and have excellent magnetic permeability and corrosion resistance. In addition to silicon steel sheets, the stator core can also be made of materials such as aluminum alloys and copper-nickel alloys.
[0066] In the embodiments of this specification, the rotor assembly 2 includes a magnet assembly 22 arranged circumferentially around the power shaft 21. The magnet assembly 22 may include a first magnet 221 and a second magnet 222 that are arc-shaped. To more clearly illustrate the shapes of the first magnet 221 and the second magnet 222, Figure 3 A schematic diagram of a magnet structure is provided for an embodiment of this specification, such as... Figure 3 As shown, the cross-sections of the first magnet 221 and the second magnet 222 can be arc-shaped, specifically including an outer arc 2211 and an inner arc 2212 distributed radially, and two side edges 2213 connecting the corresponding ends of the outer arc and the inner arc respectively; the central angles of the outer arc 2211 and the inner arc 2212 are the same.
[0067] Figure 4 This is a schematic diagram of the central angle structure of a magnet provided as an embodiment of this specification. Figure 4As shown, the central angle corresponding to the outer arc 2211 can be the included angle between the two first connection line segments after the two end points of the outer arc 2211 are connected with the center of the power shaft 21. The central angle of the outer arc of the first magnet 221 can be referred to as the first central angle 223; and the central angle of the outer arc of the second magnet 222 can be referred to as the second central angle 224. The central angle corresponding to the inner arc 2212 can be the included angle between the two second connection line segments after the two end points of the inner arc 2212 are connected with the center of the power shaft 21. Since the central angle of the outer arc 2211 is the same as and coincides with the central angle of the inner arc 2212, the central angle of the inner arc of the first magnet 221 can also be referred to as the first central angle 223; and the central angle of the inner arc of the second magnet 222 can also be referred to as the second central angle 224. It can be understood that the two first connection line segments can have overlapping portions with the two sides, and the two second connection line segments can also have overlapping portions with the two sides. The arc-shaped magnet shape can better match the shape of the air gap 4 between the rotor assembly 2 and the stator assembly 1, which helps to generate a more uniform magnetic field distribution, thereby reducing vibration and noise caused by uneven magnetic field.
[0068] In the embodiments of the present specification, the angles of the central angles corresponding to the outer arcs and the inner arcs are within a first preset included angle range, which can be 42° to 57°; wherein the angle of the first central angle corresponding to the outer arc of the first magnet 221 is the same as the angle of the second central angle corresponding to the outer arc of the second magnet 222. Specifically, the first magnet 221 and the second magnet 222 can be magnets whose angles of the central angles corresponding to the outer arcs and the inner arcs are both 49.5°; the first magnet 221 and the second magnet 222 can be magnets whose angles of the central angles corresponding to the outer arcs and the inner arcs are both 45°; and the first magnet 221 and the second magnet 222 can be magnets whose angles of the central angles corresponding to the outer arcs and the inner arcs are both 54°.
[0069] The thickness of the first magnet 221 and the second magnet 222 in the embodiments of the present specification can be within a preset thickness range, which can be 1-2 mm. The thickness of the first magnet 221 and the second magnet 222 can be the distance between the outer arc and the inner arc in the radial direction. It can be understood that the distance between the outer arc and the inner arc in the radial direction can represent the shortest distance between the outer arc and the inner arc. Specifically, the thickness of the first magnet 221 and the second magnet 222 can be configured to be 1.5 mm. Specifically, the shortest distance between the tangent line of the inner arc parallel to the tangent line of the outer arc can be 1.5 mm. The first magnet 221 and the second magnet 222 can also be configured as magnets with a thickness of 1.2 mm, 1.8 mm, etc. The thickness of the first magnet 221 and the second magnet 222 can be determined based on the spatial distance between the power shaft 21 and the stator assembly 1. An appropriate magnet thickness can be selected to ensure that the magnet is arranged on the power shaft 21 and has a certain gap with the stator assembly 1, while also ensuring that the magnetic field generated by the magnet meets the preset requirements, thereby reducing the cogging torque, increasing the swing angle, and reducing the frequency without affecting the rotation of the rotor assembly 2.
[0070] To more clearly illustrate the interval arrangement of the magnet assembly 22 on the power shaft 21, Figure 5 A structural diagram of a third central angle of the interval arrangement of the first magnet and the second magnet on the power shaft is provided for the embodiments of the present specification. As Figure 5 shown, the interval of the first magnet 221 and the second magnet 222 on the power shaft 21 in the embodiments of the present specification can be configured as a third central angle 225 within a third preset angle range, which can be 23.5°-38°. The interval between the first magnet 221 and the second magnet 222 in one magnet assembly 22 corresponds to a third central angle 225 which can be set to 25°, 27°, 30.5°, 34.4°, etc. Specifically, the third central angle 225 can represent the included angle between the first connection line segment and the second connection line segment that are closest to each other in the first magnet 221 and the second magnet 222. It can be understood that when configuring the rotor assembly 2, the angle of the third central angle 225 of the interval between the first magnet 221 and the second magnet 222 can be reasonably set, thereby making the magnetic field generated by the magnet assembly 22 more uniform, reducing the cogging torque, and thereby increasing the swing angle and reducing the frequency.
[0071] In the actual construction of the motor, two stator cores 11 can be provided, and the two stator cores 11 can be constructed to be symmetrically distributed; two magnet assemblies 22 that cooperate with the stator cores 11 can also be provided; one magnet assembly 22 can correspond to one stator core 11; the first included angle 226 between the two magnet assemblies 22 can be greater than the third central angle 225 between the first magnet 221 and the second magnet 222 in the magnet assembly 22; so that one stator core 11 and one magnet assembly 22 can cooperate with each other, avoiding abnormal influence on adjacent magnet assemblies 22, so that the motor cannot operate normally.
[0072] To more clearly illustrate the construction of the first magnet 221 and the second magnet 222 on the rotor core 211, Figure 6 This specification provides a schematic diagram of the structure of a second included angle for an embodiment, as shown below. Figure 6 As shown in the embodiment of this specification, in a plane perpendicular to the rotation axis of the rotor assembly 2, the second included angle 227 between the centerline of the first magnet 221 and the centerline of the second magnet 222 is within a second preset included angle range; the second preset included angle range is 73° to 87°. The centerline of the first magnet 221 can be a line pointing from the center of the first magnet 221 to the rotation axis; the centerline of the second magnet 222 can be a line pointing from the center of the second magnet 222 to the rotation axis. The rotation axis can represent the centerline of the power shaft 21. It is understood that the centerline of the first magnet 221 can be perpendicular to the rotation axis; the centerline of the second magnet 222 can also be perpendicular to the rotation axis. The second included angle 227 can be set to 75°, 79°, 83°, 85°, etc. In practical applications, the size of the second included angle 227 can also be set based on actual needs, and no specific limitation is made here.
[0073] Figure 7 This is a schematic diagram of the third included angle structure provided in the embodiments of this specification, as shown below. Figure 7 As shown in the embodiment of this specification, the third included angle 228 formed by the two outer boundaries of the magnet assembly 22 extending to the rotation axis of the rotor assembly 2 is within the range of the fourth preset included angle; the range of the fourth preset included angle is 122° to 141°. Specifically, the third included angle 228 can be constructed as 127°; the third included angle 228 can also be constructed as 127.5°; the third included angle 228 can also be constructed as 136°, thereby making the magnet assembly 22 occupy a more reasonable proportion on the power shaft 21, avoiding the magnet assembly 22 occupying too large a proportion on the power shaft 21, which would prevent the rotor assembly 2 from reciprocating; or avoiding the magnet assembly 22 occupying too small a proportion on the power shaft 21, which would reduce the fit between the rotor assembly 2 and the stator assembly 1, making the rotor assembly 2 unable to operate normally.
[0074] In this embodiment, the power shaft 21 may include a mounting groove 2111 for mounting the magnet assembly 22. Specifically, the magnets in the magnet assembly 22 can be embedded into the mounting groove 2111 using an adhesive, such as glue. Alternatively, the magnets in the magnet assembly 22 can be placed into the mounting groove 2111 by welding. The first magnet 221 and the second magnet 222 in the magnet assembly 22 can be respectively embedded into different mounting grooves 2111, thereby fixing the magnets in the magnet assembly 22 in the mounting grooves 2111 at intervals, preventing the magnet assembly 22 from falling off the mounting grooves 2111 and affecting the normal operation of the motor.
[0075] In this embodiment, the number of mounting slots 2111 can be set according to the number of magnet assemblies 22. Preferably, the number of magnet assemblies 22 can be 2, and correspondingly, the number of mounting slots 2111 can be 4. The depth of the mounting slot 2111 can be 0.7 mm; the distance between the bottom of the mounting slot 2111 and the rotation axis is 2.5 mm; the distance between the outer arc of the magnet in the magnet assembly 22 and the rotation axis is 4 mm. It can be understood that part of the magnet in the magnet assembly 22 is exposed outside the mounting slot 2111, thereby enhancing the fit between the rotor assembly 2 and the stator assembly 1.
[0076] Figure 8 This is a schematic diagram of the fourth central angle structure provided in the embodiments of this specification, as shown below. Figure 8 As shown in the embodiments of this specification, in a plane perpendicular to the rotation axis of the rotor assembly 2, the ratio of the central angle corresponding to the outer arc of the first magnet 221 facing the stator core 11 to the fourth central angle 229 corresponding to the inner arc of the stator core 11 facing the magnet assembly 22 can range from 60% to 85%; the ratio of the central angle corresponding to the outer arc of the second magnet 222 facing the stator core 11 to the fourth central angle 229 corresponding to the inner arc of the stator core 11 facing the magnet assembly 22 can also range from 60% to 85%. By setting a reasonable ratio range between the central angle corresponding to the outer arc of a single magnet and the central angle corresponding to the inner arc of the stator core, the cogging torque can be reduced, the swing angle increased, and the vibration frequency of the motor reduced.
[0077] In practical applications, the cogging torque can be reduced and the swing angle increased by setting a reasonable ratio range between the arc length of the outer arc of a single magnet and the arc length of the inner arc of the stator core. Specifically, in a plane perpendicular to the rotation axis of the rotor assembly 2, the ratio of the arc length of the outer arc of the first magnet 221 facing the stator core 11 to the arc length of the inner arc of the stator core 11 facing the magnet assembly 22 is between 60% and 70%; the ratio of the arc length of the outer arc of the second magnet 222 facing the stator core 11 to the arc length of the inner arc of the stator core 11 facing the magnet assembly 22 is also between 60% and 70%. The arc length of the inner arc of the stator core 11 facing the magnet assembly 22 may include the chamfered portion of the stator core 11; it may also exclude the chamfered portion of the stator core 11, depending on the actual structural requirements of the motor.
[0078] Figure 9 This is a schematic diagram of the fifth central angle structure provided in the embodiments of this specification, as shown below. Figure 9 As shown in the embodiment of this specification, when the rotor assembly 2 is in the equilibrium position, the first magnet 221 and the second magnet 222 correspond to the two sides of the stator core 11, respectively. The radial center projection of the first magnet 221 and the stator core 11 overlaps, and the radial center projection of the second magnet 222 also overlaps. The ratio of the central angle corresponding to the overlapping projection of the first magnet 221 and the stator core 11 to half the central angle corresponding to the inner arc of the stator core 11 ranges from 40% to 70%. The central angle corresponding to the overlapping projection of the first magnet 221 and the stator core 11 to half the central angle corresponding to the inner arc of the stator core 11 also ranges from 40% to 70%. This central angle can be referred to as the fifth central angle 230. The central projection can be a projection of the first magnet 221, the second magnet 222, and the stator core 11 onto a point on the rotation axis when the rotor assembly 2 is in the equilibrium position. This allows for a high degree of fit between the stator core 11 and the magnet assembly 22, reducing cogging torque. This increases the swing angle of the rotor assembly while maintaining a relatively constant motor output torque, thus better meeting the teeth-cleaning needs of different consumers. Furthermore, it reduces the motor's vibration frequency, preventing excessive toothache and sensitivity caused by high-frequency vibration, and also avoiding increased motor noise due to high-frequency vibration, thereby improving the user experience of oral hygiene equipment with this type of motor.
[0079] In the actual construction process of the motor, the width range of the air gap 4 between the outer side arc of the first magnet 221 and the second magnet 222 and the inner side arc of the stator core 11 facing the magnet assembly 22 can be set to 0.15-0.25 mm, so that the cooperation between the rotor assembly 2 and the stator assembly 1 can be improved without affecting the normal operation of the rotor assembly 2.
[0080] As another embodiment, the ratio of the central angle corresponding to the projection overlap part of the first magnet 221 and the stator core 11 to the central angle corresponding to the outer side arc length of the first magnet 221 facing the stator core 11 is 30%-45%, and the ratio of the central angle corresponding to the projection overlap part of the second magnet 222 and the stator core 11 to the central angle corresponding to the outer side arc length of the second magnet facing the stator core 11 is 30%-45%. Preferably, the ratio range can also be set to 35%-40%. Specifically, the ratio range can be set to 35%, 37%, 40%, etc., to improve the cooperation between the stator core 11 and the magnet assembly 22.
[0081] As shown in Figure 1 The motor housing 3 can also be provided with a limiting piece 31, which can be used to prevent the rotor assembly 2 from rotating beyond a predetermined angle threshold, thereby facilitating normal use of the motor and avoiding the situation that the motor cannot operate normally due to excessive rotation of the rotor assembly 2.
[0082] In the embodiments of the present application, the motor housing 3 can also not be provided with a limiting piece 31, so that the rotatable angle of the rotor assembly 2 under the action of external force can be greater than 360°, i.e. the rotatable angle of the rotor assembly 2 under the action of external force can be any value. When the external force is removed, the rotor assembly 2 can be reset to the balance position under the action of the cogging torque. Specifically, the balance position of the rotor assembly 2 can be determined according to the angle between the current unbalanced position and the first balance position and the second balance position. For example, when the external force is removed, the rotor assembly 2 can be reset to the first balance position or the second balance position with the smallest angle.
[0083] In the embodiments of the present specification, the stator assembly 1 is in a non-energized state, and the rotor assembly 2 can have a balance position matched with the stator core 11. The rotor assembly 2 can be in the balance position when it is not subjected to external force; the balance position can be a position where the rotor assembly 2 is in a static state relative to the stator assembly 1; and the balance position can ensure normal starting of the motor. In actual application, the number of balance positions corresponds to the number of stator cores 11, for example, when the stator assembly 1 includes only one pair of stator cores 11, the rotor assembly 2 can include two balance positions, i.e., a first balance position and a second balance position. Here, the two stator cores 11 in the pair of stator cores 11 can be mirror-symmetric, and the included angle between the first balance position and the second balance position can range from 180°-3° to 180°+3°.
[0084] In the embodiments of the present specification, if no limiting member is arranged on the motor housing, the rotor assembly 2 can rotate by any angle under the action of external force, so that the user can manually rotate the brush head to any desired balance position or near any desired balance position as needed; for example, for oral cleaning equipment in which the bristle area on the brush head and the electronic display area are located on the same side. It can be understood that at this time, the rotor assembly 2 is located at one of the balance positions. When the user needs to view the prompt information displayed in the electronic display area from the mirror to avoid stopping brushing to view the relevant prompt information, the user can manually rotate the brush head by 180°, so that the bristle area and the electronic display area are directed to different sides, thereby enabling the user to view the prompt information displayed in the electronic display area from the mirror, while not affecting the user's brushing process, meeting the user's needs and improving the user's convenience in using the oral cleaning equipment. It can be understood that after the user manually rotates the brush head by 180°, the rotor assembly 2 is located at the other balance position.
[0085] In this embodiment of the specification, the motor may further include an electromagnetic coil 5 disposed around the stator core 11. In response to a control signal applied to the electromagnetic coil 5, the stator core 11 causes the rotor assembly 2 to rotate relative to the stator core 11 about a rotation axis. Furthermore, the unidirectional rotation angle of the rotor assembly 2 relative to the stator core 11 about the rotation axis is 0° to 20°, and the bidirectional rotation angle is 0° to 40°. This increases the oscillation angle while the motor is operating normally, helping to meet the teeth cleaning needs of different consumers. The motor operates at a frequency range of 100 Hz to 180 Hz; further, it can operate normally and stably between 140 Hz and 150 Hz. This reduces the motor's vibration frequency, avoiding the prominent toothache and tooth sensitivity caused by high-frequency vibration, and also preventing increased motor noise due to high-frequency vibration, thus improving the user experience of oral cleaning devices with this type of motor.
[0086] Figure 10 This is a structural schematic diagram of the power shaft provided in the embodiments of this specification. Figure 10 As shown, the power shaft 21 may include a rotor core 211 and an output shaft 212 disposed at the center of the rotor core 211. The output shaft 212 can be used to connect with the working parts of an oral hygiene device, such as a toothbrush head or a water flosser head, so that the output shaft 212 can drive the working parts of the oral hygiene device to clean teeth and gums. The rotor core 211 is also provided with a mounting groove 2111 for mounting the magnet assembly 22.
[0087] In the embodiments described in this specification, at least one plane in the plane containing the rotation axis of the rotor assembly 2 is a plane of symmetry; the stator core 11 is mirror-symmetrically arranged with respect to this plane of symmetry, and / or the first magnet 221 and the second magnet 222 are mirror-symmetrically arranged with respect to this plane of symmetry. When in the equilibrium position, the plane of symmetry used for the symmetrical arrangement of the stator core 11 is the same plane of symmetry used for the symmetrical arrangement of the first magnet 221 and the second magnet 222. By symmetrically arranging the stator core and magnets, the magnetic field distribution can be made more uniform, which is beneficial to the normal operation of the motor.
[0088] If the magnet assembly 22 is two in the embodiment of the present specification, the adjacent magnets between the two magnet assemblies 22 are configured to have the same polarity. For example, the motor includes a first magnet assembly and a second magnet assembly; the first magnet assembly includes a third magnet and a fourth magnet; the second magnet assembly includes a fifth magnet and a sixth magnet; wherein the third magnet is adjacent to the fifth magnet, the fourth magnet is adjacent to the sixth magnet, and the included angle between the third magnet and the fourth magnet is smaller than the included angle between the third magnet and the fifth magnet; if the polarity of the third magnet and the fifth magnet is S pole, then the polarity of the fourth magnet and the sixth magnet is N pole; if the polarity of the third magnet and the fifth magnet is N pole, then the polarity of the fourth magnet and the sixth magnet is S pole.
[0089] In practical applications, the motor can be arranged in an oral cleaning device, and specifically can be connected with a brush head through a rotating shaft, so that the rotor assembly 2 can drive the toothbrush to reciprocate when reciprocating under the influence of the stator assembly 1, thereby cleaning the teeth at a larger angle and improving the cleaning angle and the cleaning ability of the oral cleaning device.
[0090] Figure 11 A distribution diagram of simulation data of cogging torque of the motor in the embodiment of the present specification; Figure 12 A distribution diagram of simulation data of torque of the motor in the embodiment of the present specification; Figure 11 and Figure 12 The parameters of the test sample are as follows:
[0091] Figure 11 Scheme A represented by the dotted line in the middle of Figure 12 The central angle of the first magnet 221 and the second magnet 222 in the magnet assembly 22 is 49.5°, that is, the central angles of the outer arc and the inner arc of the first magnet 221 and the second magnet 222 are both 49.5°; the third central angle 225 of the interval between the first magnet 221 and the second magnet 222 is 28.5°; the magnet thickness is configured to be 1.5 mm; the depth of the mounting groove 2111 is configured to be 0.7 mm; the angle of the first included angle between the two magnet assemblies 22 is configured to be 52.5°.
[0092] Figure 11 Scheme B represented by the solid line in Figure 12 The central angle of the first magnet 221 and the second magnet 222 in the magnet assembly 22 is 45°, that is, the central angles of the outer arc and the inner arc of the first magnet 221 and the second magnet 222 are both 45°; the third central angle 225 of the interval between the first magnet 221 and the second magnet 222 is 37°; the magnet thickness is configured to be 1.5 mm; the depth of the mounting groove 2111 is configured to be 0.7 mm; the angle of the first included angle between the two magnet assemblies 22 is configured to be 53°.
[0093] Figure 11 The middle dashed line and Figure 12 Scheme C is represented by the dashed line in the diagram; the central angle between the first magnet 221 and the second magnet 222 in the magnet assembly 22 is 54°, that is, the central angles between the outer and inner arcs of the first magnet 221 and the second magnet 222 are both 54°; the third central angle 225 of the interval between the first magnet 221 and the second magnet 222 is 28°; the magnet thickness is constructed to be 1.5 mm; the depth of the mounting groove 2111 is constructed to be 0.7 mm; the angle of the first included angle between the two magnet assemblies 22 is constructed to be 44°.
[0094] Understandably, as the rotation angle of rotor assembly 2 in the motor changes, the cogging torque of the motor will also change. Figure 11 This is used to illustrate the relationship between the cogging torque of the motor and the rotor assembly 2 in the motor. Figure 11 The horizontal axis in the figure can represent the rotation angle of the rotor assembly 2 in the motor; the vertical axis can represent the cogging torque corresponding to the rotation angle of the rotor assembly 2.
[0095] For motors used in oral hygiene devices such as electric toothbrushes, the electromagnetic torque and cogging torque resist each other during the motor's oscillation. Reducing the cogging torque, under the same electromagnetic torque, facilitates an increase in the oscillation angle and simultaneously lowers the resonant frequency. Simulation tests were conducted on the motors described in the embodiments of this specification. Figure 12 These are experimental data obtained under a load of 0.5A forward current. The horizontal axis represents the rotation angle of rotor assembly 2; the vertical axis represents the motor torque. From Figure 12 A schematic diagram of the distribution of simulated motor torque data. Figure 11 The distribution diagram of the simulated cogging torque data shows that the zero-position torque of scheme A is 9.03 mN.m and the NR position is 8.04°; the zero-position torque of scheme B is 8.23 mN.m and the NR position is 9.71°; and the zero-position torque of scheme C is 9.6 mN.m and the NR position is 9.16°. Based on this, the zero-position torque of the motor in the embodiment of this specification is low. This is because the modified electromagnetic structure significantly reduces the cogging torque and also has a certain impact on the starting torque at the equilibrium position. The NR position angle is increased, that is, the position angle at which the electromagnetic torque and the cogging torque cancel each other out to 0. This is beneficial for a larger swing angle and a lower resonant frequency.
[0096] In the embodiment of the present specification, when the motor is in the state of no-load I=0A, the rotor is stationary at zero position, and no output torque. When a positive current is applied, the rotor assembly 2 generates a zero position torque in a negative direction, and rotates in this direction until it reaches a natural return NR position where the output torque is equal to 0Nm, and then shifts to the positive direction. Thereafter, if it is a positive current, the rotor assembly 2 will rotate backward around the NR position and stop at the preset NR position. If a negative current is applied, the direction of rotation of the rotor assembly 2 can be opposite to that when a positive current is applied, so that the rotor assembly 2 in the motor reciprocates by applying an alternating current.
[0097] For the purposes of the description hereinafter, spatially relative terms, such as "above", "below", "up", "down", "top", "bottom", "horizontal", "vertical", "upper", "lower", and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if a device in the figures is inverted, elements described as "above" or "up" other elements or features would then be oriented "below" or "down" the other elements or features. Thus, the exemplary term "above" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. The terms "first", "second", "third", etc., do not necessarily indicate any ordinal, chronological or other sequence unless expressly stated to do so.
[0098] It is to be noted that the terms used herein are merely for the purpose of describing specific embodiments and are not intended to limit exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising", when used in this specification, specify the presence of stated features, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof.
[0099] It should be noted that the terms "first", "second", and the like, used in the specification and the claims herein, are used to distinguish between similar objects, and are not necessarily used to describe a particular sequential or chronological order. Rather, these terms are used to distinguish between objects having
[0100] The above only describes the embodiments of the present application and is not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the scope of claims of the present application.
Claims
1. An electric motor for use in an oral cleaning device, characterized in that The motor comprises: a stator assembly arranged to generate a magnetic field, wherein the stator assembly comprises at least one stator core; a rotor assembly arranged at least partially within the magnetic field of the stator assembly, the rotor assembly comprising a power shaft and a magnet assembly arranged on the power shaft and cooperating with the stator core; the stator core is configured to drive the rotor assembly to reciprocate at a predetermined angle in an energized state; wherein each of the magnet assemblies is configured to comprise a first magnet and a second magnet arranged circumferentially around the power shaft and cooperating with the same stator core, the first magnet and the second magnet being spaced apart on the power shaft; and at least part of the first magnet close to the stator core and at least part of the second magnet close to the stator core are configured to have different polarities.
2. The electric machine of claim 1, wherein, The first magnet and the second magnet are both in the shape of a circular arc, comprising an outer circular arc and an inner circular arc distributed in the radial direction, and two side edges respectively connecting the two ends of the outer circular arc and the inner circular arc; the angles of the corresponding central angles of the outer circular arc and the inner circular arc are the same.
3. The electric machine of claim 2, wherein, The angles of the corresponding central angles of the outer circular arc and the inner circular arc are both within a first preset angle range; the first preset angle range is 42° to 57°; the angle of the first central angle corresponding to the outer circular arc of the first magnet is the same as the angle of the second central angle corresponding to the outer circular arc of the second magnet.
4. The electric machine of claim 3, wherein, The angles of the corresponding central angles of the outer circular arc and the inner circular arc are both configured to be 49.5°.
5. The electric machine of claim 3, wherein, The angles of the corresponding central angles of the outer circular arc and the inner circular arc are both configured to be 45°.
6. The electric machine of claim 3, wherein, The angles of the corresponding central angles of the outer circular arc and the inner circular arc are both configured to be 54°.
7. The electric machine of claim 2, wherein, The thicknesses of the first magnet and the second magnet are both within a preset thickness range; the preset thickness range is 1mm to 2mm; the thicknesses of the first magnet and the second magnet are the distances of the outer circular arc and the inner circular arc in the radial direction.
8. The electric machine of claim 7, wherein, The thicknesses of the first magnet and the second magnet are both configured to be 1.5mm.
9. The electric machine of claim 1, wherein, In a plane perpendicular to the rotation axis of the rotor assembly, a second included angle between the center line of the first magnet and the center line of the second magnet is within a second preset angle range; the second preset angle range is 73° to 87°; the center line of the first magnet is a line from the center of the first magnet to the rotation axis, and the center line of the second magnet is a line from the center of the second magnet to the rotation axis.
10. The electric machine of claim 1, wherein, The interval of the first magnet and the second magnet on the power shaft is configured to be a third central angle within a third preset angle range; the third preset angle range is 23.5° to 38°.
11. The electric machine of claim 1, wherein, Two outer boundaries of the magnet assembly extend to a third included angle formed on the rotation axis of the rotor assembly, which is within a fourth preset angle range; the fourth preset angle range is 122° to 141°.
12. The electric machine of claim 11, wherein, The third included angle is configured to be 127°.
13. The electric machine of claim 11, wherein, The third included angle is configured to be 127.5°.
14. The electric machine of claim 11, wherein, The third included angle is configured to be 136°.
15. The electric machine of claim 1, wherein, The power shaft comprises a mounting groove; the mounting groove is used for mounting the magnet assembly.
16. The electric machine of claim 15, wherein, The magnets in the magnet assembly are embedded into the mounting groove by an adhesive.
17. The electric machine of claim 15, wherein, The number of the mounting grooves is four.
18. The electric machine of claim 1, wherein, When in the balanced position, the first magnet and the second magnet correspond to two sides of the stator core respectively, and the first magnet overlaps with the central projection part of the stator core in the radial direction, and the second magnet overlaps with the central projection part of the stator core in the radial direction. The ratio of the central angle corresponding to the projection overlap part of the first magnet and the stator core to half of the central angle corresponding to the inner arc of the stator core ranges from 40% to 70%; the ratio of the central angle corresponding to the projection overlap part of the second magnet and the stator core to half of the central angle corresponding to the inner arc of the stator core ranges from 40% to 70%.
19. The electric machine of claim 18, wherein, The ratio of the central angle corresponding to the projection overlap part of the first magnet and the stator core to the central angle corresponding to the outer arc of the stator core facing the first magnet ranges from 30% to 45%; the ratio of the central angle corresponding to the projection overlap part of the second magnet and the stator core to the central angle corresponding to the outer arc of the stator core facing the second magnet ranges from 30% to 45%.
20. The electric machine of claim 1, wherein, The motor comprises electromagnetic coils arranged around the stator core, and the stator core rotates the rotor assembly relative to the stator core around the rotation axis in response to a control signal applied to the electromagnetic coils.
21. The electric machine of claim 1, wherein, The frequency range of the motor in the running state ranges from 100 Hz to 180 Hz.
22. The electric machine of claim 1, wherein, The width of the air gap between the outer arc of the first magnet and the second magnet and the inner arc of the stator core facing the magnet assembly ranges from 0.15 mm to 0.25 mm.
23. The electric machine of any of claims 1-22, wherein, The stator core is provided with two stator cores which are configured to be symmetrically distributed; the magnet assembly is provided with two magnet assemblies; one magnet assembly corresponds to one stator core; the first included angle between the two magnet assemblies is greater than the third central angle between the first magnet and the second magnet in the magnet assembly.
24. The electric machine of claim 1, wherein, At least one plane containing the rotation axis of the rotor assembly is a plane of symmetry; The stator core is mirror-symmetrically arranged with the plane of symmetry as the reference plane, and / or, The first magnet and the second magnet are mirror-symmetrically arranged with the plane of symmetry as the reference plane.
25. An oral cleaning device, characterized by The oral cleaning device has the motor according to any one of claims 1-24.