Motor and oral cavity cleaning equipment
By optimizing the ratio range of the center angle of the overlapping part of the motor magnet and the stator core projection, the problems of small swing angle and high-frequency vibration in the prior art are solved, and the brush head swing and vibration frequency reduction of the brush head swing at a larger angle are achieved , improves the user experience.
Patent Information
- Application Number
- CN202411672051.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-20
- Publication Date
- 2025-02-18
AI Technical Summary
The motor of existing oral cleaning equipment has a small angle that drives the brush head to swing, which is difficult to meet the teeth cleaning needs of different consumers. At the same time, high-frequency vibration will cause discomfort and noise such as toothache, dental acid and increase.
By optimizing the ratio range of the center angle of the motor's magnet and the overlapping part of the projection of the stator core, the cogging torque is reduced, and the swing angle of the rotor assembly is increased, thereby increasing the swing angle of the brush head and reducing the vibration frequency of the motor.
When the motor output torque is basically unchanged, the swing angle of the brush head is increased to meet the teeth cleaning needs of different consumers, and at the same time reduce the vibration frequency of the motor, avoiding discomfort and noise increase caused by high-frequency vibration .
Smart Images
Figure CN119483024A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of motors, and in particular to a motor and an oral cleaning device having the motor. Background Art
[0002] A motor is an electromagnetic device that converts or transmits electrical energy based on the law of electromagnetic induction.
[0003] Oral cleaning equipment uses a high-speed vibrating motor shaft to drive the brush head to swing or vibrate to achieve the effect of cleaning teeth. The oral cleaning equipment uses the motor to make the brush head produce high-frequency vibration, which can break down toothpaste into fine foam and deeply clean the gaps between teeth. Therefore, oral cleaning equipment has a stronger cleaning ability than traditional toothbrushes. At present, the vibration frequency of the motor of oral cleaning equipment is usually higher than 200 Hz.
[0004] Furthermore, the motor of current oral cleaning equipment drives the brush head to swing at a relatively small angle, which generally does not exceed 10°, making it difficult to meet the teeth cleaning needs of different consumers.
[0005] Based on this, how to provide a motor with a larger swing angle for use in oral cleaning equipment has become a technical problem that needs to be solved urgently. Summary of the invention
[0006] The embodiments of this specification propose a motor to solve the problem that the swing angle of the motor in the existing oral cleaning equipment is small, which affects the user experience.
[0007] In order to solve the above technical problems, an embodiment of the present specification provides a motor, the motor comprising: a stator assembly arranged to generate a magnetic field, wherein the stator assembly comprises at least one stator core; a rotor assembly at least partially arranged in the magnetic field of the stator assembly, the rotor assembly comprising a power shaft and a magnet assembly disposed on the power shaft and cooperating with the stator core; each of the magnet assemblies is configured to include a first magnet and a second magnet arranged circumferentially around the power shaft and cooperating with the same stator core, at least a portion of the first magnet close to the stator core and at least a portion of the second magnet close to the stator core being configured to have different polarities; When in a 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 of the stator core in the radial direction, and the second magnet overlaps with the central projection of the stator core in the radial direction; The ratio of a first central angle corresponding to the overlapping portion of the projection of the first magnet and the stator core to half of a second central angle corresponding to the inner arc of the stator core facing the magnet assembly is in a range of 40% to 70%; and / or, The ratio of the third central angle corresponding to the overlapping portion of the projection of the second magnet and the stator core to half of the second central angle is in a range of 40% to 70%; and / or, The first central angle is the same as the third central angle.
[0008] Optionally, in a plane perpendicular to the rotation axis of the rotor assembly, a fourth center angle corresponding to an outer circular arc of the first magnet facing the stator core has a ratio to the second center angle in a range of 60% to 85%; a fifth center angle corresponding to an outer circular arc of the second magnet facing the stator core has a ratio to the second center angle in a range of 60% to 85%.
[0009] Optionally, in a plane perpendicular to the rotation axis of the rotor assembly, the ratio of the arc length of the outer arc of the first magnet facing the stator core to the arc length of the inner arc of the stator core facing the magnet assembly is in a range of 60% to 70%; the ratio of the arc length of the outer arc of the second magnet facing the stator core to the arc length of the inner arc of the stator core facing the magnet assembly is in a range of 60% to 70%.
[0010] Optionally, among the planes containing the rotation axis of the rotor assembly, at least one plane is a symmetry plane; the stator core is mirror-symmetrically arranged with the symmetry plane as a reference plane, and / or the first magnet and the second magnet are mirror-symmetrically arranged with the symmetry plane as a reference plane.
[0011] Optionally, the ratio of the first central angle to the fourth central angle ranges from 30% to 45%; the ratio of the third central angle to the fifth central angle ranges from 30% to 45%.
[0012] Optionally, the ratio of the first central angle to the fourth central angle ranges from 35% to 40%; the ratio of the third central angle to the fifth central angle ranges from 35% to 40%.
[0013] Optionally, in a plane perpendicular to the rotation axis of the rotor assembly, the first angle between the center line of the first magnet and the center line of the second magnet ranges from 73° to 87°; the center line of the first magnet is a line pointing from the center of the first magnet to the rotation axis, and the center line of the second magnet is a line pointing from the center of the second magnet to the rotation axis.
[0014] Optionally, the first magnet and the second magnet are both arc-shaped, including an outer arc and an inner arc distributed in the radial direction, and two side edges respectively connecting the corresponding two ends of the outer arc and the inner arc; the central angles of the outer arc and the inner arc are the same.
[0015] Optionally, the width of the air gap between the outer arcs 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.
[0016] Optionally, the thickness of the first magnet and the second magnet are both within a preset thickness range; the preset thickness range is 1 mm to 2 mm; the thickness of the first magnet and the second magnet is the radial distance between the outer arc and the inner arc.
[0017] Optionally, the thickness of the first magnet and the second magnet are both 1.5 mm.
[0018] Optionally, the first magnet and the second magnet are arranged around the circumference of the power shaft and are spaced apart from each other by a preset central angle spacing.
[0019] Optionally, the preset central angle ranges from 23.5° to 38°.
[0020] Optionally, the preset center angle is 28.5°.
[0021] Optionally, the motor includes a motor housing; and the rotor assembly is disposed in the motor housing.
[0022] Optionally, a limit member is provided on the motor housing; the limit member is used to prevent the rotor assembly from rotating beyond a preset angle threshold.
[0023] Optionally, the power shaft includes an output shaft and a magnetic conductive member.
[0024] Optionally, the power shaft includes a mounting groove; the mounting groove is used to install the magnet assembly.
[0025] Optionally, the number of the mounting slots is 4.
[0026] Optionally, the groove depth of the mounting groove is 0.7 mm.
[0027] Optionally, the magnet in the magnet assembly is embedded in the mounting groove by an adhesive.
[0028] Optionally, the motor includes an electromagnetic coil disposed around the stator core, and in response to a control signal applied to the electromagnetic coil, the stator core causes the rotor assembly to rotate relative to the stator core around a rotation axis of the rotor assembly.
[0029] Optionally, the stator core enables the rotor assembly to rotate unidirectionally around the rotation axis relative to the stator core in an angle range of 0° to 20°; the stator core enables the rotor assembly to rotate bidirectionally around the rotation axis relative to the stator core in an angle range of 0° to 40°.
[0030] Optionally, two stator cores are provided, and the two stator cores are constructed to be symmetrically distributed; two magnet assemblies are provided; each magnet assembly corresponds to one stator core; and a third angle between the two magnet assemblies is greater than a second angle between the first magnet and the second magnet in the magnet assembly.
[0031] Optionally, the frequency range of the motor in operation is 100 Hz to 180 Hz.
[0032] Optionally, the frequency range of the motor in operation is 140 Hz to 150 Hz.
[0033] The embodiment of the present specification also provides an oral cleaning device, and the oral cleaning device has the motor.
[0034] At least one embodiment of the present specification can achieve the following beneficial effects: by setting the reasonable ratio range of the central angle corresponding to the overlapping part of the projection of the magnet and the stator core in the rotor assembly and the central angle corresponding to the inner arc of the stator core facing the magnet when in the equilibrium position, the tooth slot torque can be reduced, so that the swing angle of the rotor assembly can be increased while the output torque of the motor remains basically unchanged, which is conducive to meeting the tooth cleaning needs of different consumers. In addition, the vibration frequency of the motor can be reduced, so as to avoid the situation where the user feels toothache, tooth acid, etc. due to high-frequency vibration, and the situation where the motor noise increases due to high-frequency vibration can be avoided, which is conducive to improving the user's experience of using an oral cleaning device with such a motor. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0036] Figure 1 A schematic diagram of the internal structure of a motor provided in an embodiment of this specification; Figure 2 A schematic diagram of the overall structure of a motor provided in an embodiment of this specification; Figure 3 A schematic diagram of the structure of the first center angle and the third center angle provided in the embodiments of this specification; Figure 4 A schematic diagram of the structure of the second central angle provided in the embodiment of this specification; Figure 5 A schematic diagram of the structure of the fourth center angle and the fifth center angle provided in the embodiments of this specification; Figure 6 A schematic diagram of the structure of the first angle provided in the embodiment of this specification; Figure 7 A schematic diagram of the structure of the second angle and the third angle provided in the embodiments of this specification; Figure 8 A schematic diagram of the structure of a first magnet provided in an embodiment of this specification; Fig. 9 A schematic diagram of the structure of a power shaft provided in an embodiment of this specification; Fig.10 A schematic diagram of the distribution of simulation data of the motor cogging torque provided in the embodiments of this specification; Fig.11 A schematic diagram of the distribution of simulation data of motor torque provided in an embodiment of this specification.
[0037] Figure numerals: 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 center angle, 224. second center angle, 225. third center angle, 226. fourth center angle, 227. fifth center angle, 228. first angle, 229. second angle, 230. third angle, 3. motor housing, 31. limiter, 4. air gap, 5. electromagnetic coil. DETAILED DESCRIPTION
[0038] In order to make the purpose, technical solutions and advantages of one or more embodiments of this specification clearer, the technical solutions of one or more embodiments of this specification will be clearly and completely described below in combination with the specific embodiments of this specification and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of one or more embodiments of this specification.
[0039] The present disclosure provides a motor, which can be used in oral cleaning devices or care devices such as electric toothbrushes, and of course can also be used in other electronic devices that require reciprocating swings, which are not listed here one by one. The motor of the present disclosure includes a motor body, and a stator assembly and a rotor assembly arranged on the motor body.
[0040] Wherein, the stator assembly is arranged on the motor body and is arranged to generate a magnetic field. Wherein, the stator assembly includes at least one stator core, which can be fixed on the motor body to provide a magnetic field for the motor. One stator core can be provided, or two or more stator cores can be provided; when more than two stator cores are provided, the stator cores are usually evenly arranged in the circumferential direction of the rotor assembly to facilitate the cyclic rotation or reciprocating swing of the rotor assembly. In a specific embodiment of the present disclosure, the stator core may include a stator core and an electromagnetic coil matched with the stator core, and when the electromagnetic coil is energized, an alternating magnetic field can be generated for the motor.
[0041] The rotor assembly disclosed in the present invention includes a power shaft and a magnet assembly arranged on the power shaft and matched with each stator core. The power shaft can be rotatably connected to the motor body through a bearing or other structure so that the power shaft can rotate relative to the motor body. Each magnet assembly is configured to include a first magnet and a second magnet arranged circumferentially around the power shaft and matched with the same stator core. That is, each stator core is matched with two magnets at the same time, for example, the first magnet and the second magnet correspond to the two side parts of the same end of the stator core respectively, and at least a part of the first magnet close to the stator core and at least a part of the second magnet close to the stator core are constructed to have different polarities. For example, when the end of the first magnet facing the stator core is an S pole, the end of the second magnet facing the stator core is an N pole, and vice versa. In this way, when the electromagnetic coil is energized to generate a magnetic field, the magnet assembly can be reciprocated by a predetermined angle under the action of the magnetic field, thereby realizing the reciprocating swing of the motor.
[0042] In the motor disclosed in the present invention, the ends of the first magnet and the second magnet facing the stator core are in the shape of an arc, and correspondingly, the ends of the stator core facing the first magnet and the second magnet are also in the shape of an arc. Wherein, when in the equilibrium position, the first magnet and the second magnet correspond to the two sides of the stator core respectively, and the first magnet and the second magnet both overlap with the radial center projection of the stator core. The ratio of the first center angle corresponding to the overlapping part of the projection of the first magnet and the stator core to half of the second center angle corresponding to the inner arc of the stator core facing the magnet assembly is in the range of 40% to 70%; and / or, the ratio of the third center angle corresponding to the overlapping part of the projection of the second magnet and the stator core to half of the second center angle is in the range of 40% to 70%; and / or, the first center angle is the same as the third center angle.
[0043] In the prior art, the vibration frequency of the motor in the oral cleaning device (such as: electric toothbrush) is usually higher than 200 Hz. On the one hand, high-frequency vibration will make the user experience bad for people with sensitive teeth, and high-frequency vibration will cause the user to feel toothache, tooth acid and other prominent sensations. On the other hand, high-frequency vibration will increase the noise of the motor and affect the user experience. In addition, the motor of the current oral cleaning device drives the brush head to swing at a small angle, which generally does not exceed 10°, making it difficult to meet the tooth cleaning needs of different consumers.
[0044] In the motor disclosed in the present invention, by optimizing the ratio range of the central angle corresponding to the overlapping part of the projection of the magnet and the stator core in the rotor assembly and the central angle corresponding to the inner arc of the stator core facing the magnet when in the balanced position, the cogging torque of the motor can be reduced, so as to increase the swing angle of the rotor assembly when the motor output torque remains basically unchanged. When the motor disclosed in the present invention is applied to oral cleaning equipment such as electric toothbrushes, the increased swing angle of the rotor assembly is conducive to meeting the tooth cleaning needs of different consumers. In addition, the vibration frequency of the motor can also be reduced, thereby avoiding the situation where the user has prominent feelings of toothache, tooth acid, etc. due to high-frequency vibration, and can also avoid the situation where the motor noise increases due to high-frequency vibration, which is conducive to improving the user's experience of using an oral cleaning device with such a motor.
[0045] The technical solutions provided by the embodiments of this specification are described in detail below in conjunction with the accompanying drawings.
[0046] The embodiments of this specification provide a motor that can be applied to an oral cleaning device so that the oral cleaning device can work based on the motor to clean teeth and gums and protect oral health.
[0047] Figure 1 A schematic diagram of the internal structure of a motor provided in an embodiment of this specification. Figure 2 This is a schematic diagram of the overall structure of a motor provided in the embodiment of this specification. Figure 1 and Figure 2 As shown, an electric motor provided in an embodiment of the present specification may include: a stator assembly 1, which is 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 in the magnetic field of the stator assembly 1, wherein the rotor assembly 2 may include a power shaft 21 and a magnet assembly 22 arranged on the power shaft 21 and cooperating with the stator core 11; each magnet assembly 22 is configured to include a first magnet 221 and a second magnet 222 which are arranged circumferentially around the power shaft 21 and cooperating with the same stator core 11, and at least a portion of the first magnet 221 close to the stator core 11 and at least a portion of the second magnet 222 close to the stator core 11 are constructed to have different polarities.
[0048] Figure 3 This is a schematic diagram of the structure of the first center angle and the third center angle provided in the embodiments of this specification. Figure 4 This is a schematic diagram of the structure of the second central angle provided in the embodiment of this specification. Figure 3 and Figure 4 As shown, when in the equilibrium position, the first magnet 221 and the second magnet 222 correspond to the two sides of the stator core 11 respectively, and the first magnet 221 overlaps with the central projection of the stator core 11 in the radial direction, and the second magnet 222 overlaps with the central projection of the stator core 11 in the radial direction. The ratio of the first central angle 223 corresponding to the overlapping part of the projection of the first magnet 221 and the stator core 11 to half of the second central angle 224 corresponding to the inner arc of the stator core 11 facing the magnet assembly 22 is in the range of 40% to 70%; and / or, the ratio of the third central angle 225 corresponding to the overlapping part of the projection of the second magnet 222 and the stator core 11 to half of the second central angle 224 is in the range of 40% to 70%; and / or, the first central angle 223 is the same as the third central angle 225. The central projection may refer to a projection of the first magnet 221 , the second magnet 222 and the stator core 11 with a point on the rotation axis of the rotor assembly 2 as the projection center when the rotor assembly 2 is in a balanced position.
[0049] In practical applications, the stator core 11 may also include a chamfered portion. If the stator core 11 includes a chamfered portion, 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, or may not include the chamfered portion of the stator core 11. The specific situation can be set based on the actual structural requirements of the motor. Similarly, the second central angle 224 corresponding to the inner arc of the stator core 11 facing the magnet assembly 22 may include the chamfered portion of the stator core 11, or may not include the chamfered portion of the stator core 11. The specific situation can be set based on the actual structural requirements of the motor.
[0050] In the embodiment of this specification, by setting the ratio of the first central angle 223 to half of the second central angle 224 to be in the range of 40% to 70%, and the ratio of the third central angle 225 to half of the second central angle 224 to be in the range of 40% to 70%, the cogging torque can be reduced, so that the swing angle of the rotor assembly can be increased while the motor output torque remains basically unchanged, which is conducive to meeting the tooth cleaning needs of different consumers. In addition, the vibration frequency of the motor can be reduced, so as to avoid the situation where the user feels toothache, tooth acid, etc. due to high-frequency vibration, and the situation where the motor noise increases due to high-frequency vibration can be avoided, which is conducive to improving the user's experience of using an oral cleaning device with such a motor.
[0051] Figure 5 This is a schematic diagram of the structure of the fourth center angle and the fifth center angle provided in the embodiment of this specification. Figure 5 As shown, in a plane perpendicular to the rotation axis of the rotor assembly 2, the ratio of the fourth central angle 226 corresponding to the outer arc of the first magnet 221 facing the stator core 11 to the second central angle 224 is in the range of 60% to 85%; the ratio of the fifth central angle 227 corresponding to the outer arc of the second magnet 222 facing the stator core 11 to the second central angle 224 is in the range of 60% to 85%. By setting a reasonable ratio range of the central angle corresponding to the outer arc of a single magnet to the central angle corresponding to the inner arc of the stator core, the cogging torque can be reduced, the swing angle can be increased, and the vibration frequency of the motor can be reduced.
[0052] In practical applications, the cogging torque can be reduced and the swing angle can be increased by setting a reasonable ratio range of the arc length of the outer arc of a single magnet to the arc length of the inner arc of the stator core. Specifically, in a plane perpendicular to the axis of rotation 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 in the range of 60% to 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 in the range of 60% to 70%.
[0053] In the embodiments of this specification, in the plane containing the rotation axis of the rotor assembly 2, at least one plane is a symmetry plane; the stator core 11 is arranged in mirror symmetry with the symmetry plane as a reference plane, and / or the first magnet 221 and the second magnet 222 are arranged in mirror symmetry with the symmetry plane as a reference plane. When in the equilibrium position, the symmetry plane used for the symmetry of the stator core 11 is the same as the symmetry plane used for the symmetry of the first magnet 221 and the second magnet 222. By symmetrically arranging the stator core and the magnets, the magnetic field distribution can be made more uniform, which is beneficial to the normal operation of the motor.
[0054] As another embodiment, the ratio of the first center angle 223 to the fourth center angle 226 can be in the range of 30% to 45%; the ratio of the third center angle 225 to the fifth center angle 227 can be in the range of 30% to 45%. Preferably, the ratio of the first center angle 223 to the fourth center angle 226 can be further set to 35% to 40%; the ratio of the third center angle 225 to the fifth center angle 227 can be further set to 35% to 40%. Specifically, the ratio range can be set to values such as 35%, 37%, and 40% to improve the fit between the stator core and the magnet assembly.
[0055] Figure 6 This is a schematic diagram of the structure of the first angle provided in the embodiment of this specification. Figure 6As shown, in a plane perpendicular to the rotation axis of the rotor assembly 2, the first angle 228 between the center line of the first magnet 221 and the center line of the second magnet 222 ranges from 73° to 87°, wherein the center line of the first magnet 221 is a line pointing from the center of the first magnet 221 to the rotation axis, and the center line of the second magnet 222 is a line pointing from the center of the second magnet 222 to the rotation axis. The rotation axis may be the center line of the power shaft 21, and it can be understood that the rotation axis is also the center line of the output shaft 212. The center line of the first magnet 221 may be perpendicular to the rotation axis; the center line of the second magnet 222 may also be perpendicular to the rotation axis. The first angle 228 may range from 73° to 87°, and specifically, the first angle 228 may be set to 75°, 79°, 83°, 85°, etc. In practical applications, the size of the first angle 228 may also be set based on actual needs, and no specific limitation is made here.
[0056] Figure 7 This is a schematic diagram of the structure of the second angle and the third angle provided in the embodiment of this specification. Figure 7 As shown, the first magnet 221 and the second magnet 222 are arranged at a preset central angle spacing around the circumference of the power shaft 21; wherein the preset central angle is a second angle 229. The second angle 229 can range from 23.5° to 38°. Preferably, the second angle 229 is specifically 28.5°. It can be understood that when constructing the rotor assembly 2, the interval between the first magnet 221 and the second magnet 222 can be reasonably set so as to make the magnetic field generated by the magnet assembly 22 more uniform, thereby reducing the cogging torque, increasing the swing angle, and reducing the vibration frequency of the motor.
[0057] Specifically, two stator cores 11 may be provided, and the two stator cores 11 may be configured to be symmetrically distributed; two magnet assemblies 22 may be provided; each magnet assembly 22 may correspond to one stator core 11; and the third angle 230 between the two magnet assemblies 22 is greater than the second angle 229 between the first magnet 221 and the second magnet 222 in the magnet assembly 22. Thus, one stator core 11 and one magnet assembly 22 can cooperate with each other, avoiding abnormal effects on adjacent magnet assemblies 22, which may cause the motor to fail to operate normally.
[0058] Figure 8 This is a schematic diagram of the structure of the first magnet provided in the embodiment of this specification. Figure 8As shown, the first magnet 221 is in the shape of an arc, and may include an outer arc 2211, an inner arc 2212 distributed in the radial direction, and two side edges 2213 respectively connecting the two ends of the outer arc 2211 and the inner arc 2212, and the angles of the center angles corresponding to the outer arc 2211 and the inner arc 2212 are the same. The structure of the second magnet 222 is consistent with the structure of the first magnet 221, and is also in the shape of an arc. The center angle corresponding to the outer arc 2211 may be the angle between the two first line segments formed by the two end points of the outer arc 2211 and the center of the power shaft 21 respectively connected. The center angle corresponding to the inner arc 2212 may be the angle between the two second line segments formed by the two end points of the inner arc 2212 and the center of the power shaft 21 respectively connected. It can be understood that the two first line segments and the two side edges 2213 may have overlapping parts, and the two second line segments and the two side edges 2213 may also have overlapping parts. The arc-shaped magnet shape can better match the shape of the air gap between the rotor assembly 2 and the stator assembly 1, which helps to produce a more uniform magnetic field distribution, thereby reducing vibration and noise caused by uneven magnetic field.
[0059] In the actual process of constructing the motor, the width range of the air gap 4 between the outer arcs of the first magnet 221 and the second magnet 222 and the inner arc of the stator core 11 facing the magnet assembly 22 can be set to 0.15 mm to 0.25 mm, thereby improving the fit between the rotor assembly 2 and the stator assembly 1 without affecting the normal operation of the rotor assembly 2.
[0060] In the embodiment of the present specification, the thickness of the first magnet 221 and the second magnet 222 can be set within a preset thickness range, wherein the preset thickness range can be 1 mm to 2 mm; the thickness of the first magnet 221 and the second magnet 222 can be the distance between the outer arc 2211 and the inner arc 2212 in the radial direction. It can be understood that the distance between the outer arc 2211 and the inner arc 2212 in the radial direction can represent the shortest distance between the outer arc 2211 and the inner arc 2212. Preferably, the thickness of the first magnet 221 and the second magnet 222 can be configured to be 1.5 mm. In practical applications, the first magnet 221 and the second magnet 222 can also be configured to be 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 can have a certain gap with the stator assembly after being arranged on the power shaft, 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.
[0061] In the embodiment of this specification, the motor may further include a motor housing 3; the stator assembly 1 may be integrally injection-molded and embedded on both sides of the motor housing 3, the rotor assembly 2 may be installed in the motor housing 3, and the stator assembly 1 and the rotor assembly 2 may be coaxially adapted. The stator assembly 1 does not require manual secondary assembly, and the concentricity tolerance between the stator assembly 1 and the rotor assembly 2 may be small, which can effectively reduce the cumulative tolerance of the assembled motor, reduce the vibration generated by the rotor assembly 2 during rotation, and reduce the noise during motor operation.
[0062] In practical applications, the material of the stator core 11 can be silicon steel sheets with high magnetic permeability. 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 11 can also be made of aluminum alloy, copper-nickel alloy and other materials.
[0063] like Figure 1 As shown, a limit member 31 may also be provided on the motor housing 3, and the limit member 31 may be used to prevent the rotor assembly 2 from rotating beyond a preset angle threshold, thereby facilitating the normal use of the motor and avoiding the situation where the motor cannot operate normally due to excessive rotation of the rotor assembly 2.
[0064] In the embodiment of this specification, the motor housing 3 may not be provided with a limiter 31, so that the rotatable angle of the rotor assembly 2 under the action of an external force can be greater than 360°, that is, the rotatable angle of the rotor assembly 2 under the action of an external force can be any value. When the external force is removed, the rotor assembly 2 can be reset to the equilibrium position under the action of the cogging torque. Specifically, the equilibrium position to which the rotor assembly 2 is reset can be determined based on the angle between the current non-equilibrium position and the first equilibrium position and the second equilibrium position. For example, when the external force is removed, the rotor assembly 2 can be reset toward the first equilibrium position or the second equilibrium position of the minimum angle.
[0065] In the embodiments of the present specification, when the stator assembly 1 is in a non-powered state, the rotor assembly 2 may have a balanced position that cooperates with the stator core 11. The rotor assembly 2 may be in a balanced position when no external force is applied; the balanced position may be a position where the rotor assembly 2 is in a stationary state relative to the stator assembly 1; the balanced position may ensure the normal start-up of the motor. In practical applications, the number of balanced positions corresponds to the number of stator cores 11. For example, when the stator assembly 1 includes only a pair of stator cores 11, the rotor assembly 2 may include two balanced positions, namely a first balanced position and a second balanced position. Here, the two stator cores 11 in a pair of stator cores 11 may be mirror-symmetrical, and the first angle between the first balanced position and the second balanced position may range from 180°-3° to 180°+3°.
[0066] In the embodiment of this specification, if the motor housing is not provided with a limiter, the rotor assembly 2 can rotate at any angle under the action of an external force, so that the user can manually rotate the brush head to any desired equilibrium position as needed, or manually rotate the brush head to the vicinity of any desired equilibrium position; for example, for an oral cleaning device in which the brush wire area and the electronic display area on the brush head are located on the same side. It can be understood that at this time, the rotor assembly 2 is located at one of the equilibrium 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 180°, so that the brush wire area and the electronic display area face different sides, and then the user can 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 convenience of the user's use of the oral cleaning device. It can be understood that after the user manually rotates the brush head 180°, the rotor assembly 2 is located at another equilibrium position.
[0067] like Figure 1 and Figure 2 As shown, the motor may also include an electromagnetic coil 5 arranged around the stator core 11. In response to the control signal applied to the electromagnetic coil 5, the stator core 11 may cause the rotor assembly 2 to rotate relative to the stator core 11 around the rotation axis. In addition, the stator core 11 causes the rotor assembly 2 to rotate in one direction relative to the stator core 11 around the rotation axis in an angle range of 0° to 20°. Correspondingly, the stator core 11 causes the rotor assembly 2 to rotate in two directions relative to the stator core 11 around the rotation axis in an angle range of 0° to 40°, thereby increasing the swing angle and helping to meet the tooth cleaning needs of different consumers. The frequency range of the motor in the operating state is 100 Hz to 180 Hz; further, it can be basically stabilized to operate normally between 140 Hz and 150 Hz. Thereby reducing the vibration frequency of the motor, it can avoid the situation where the user has prominent feelings such as toothache and tooth acid due to high-frequency vibration, and it can also avoid the situation where the motor noise increases due to high-frequency vibration, which is conducive to improving the user's experience of using an oral cleaning device with such a motor.
[0068] Fig. 9 This is a schematic diagram of the structure of the power shaft provided in the embodiment of this specification. Fig. 9 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 may be used to connect to a brush head of an oral cleaning device, thereby driving the brush head to move. The rotor core 211 is also provided with a mounting groove 2111 for mounting the magnet assembly 22.
[0069] In practical applications, the magnets in the magnet assembly 22 can be embedded in the mounting groove 2111 by an adhesive, wherein the adhesive can be glue, etc. The magnets in the magnet assembly 22 can also be placed in the mounting groove 2111 by welding. The first magnet 221 and the second magnet 222 in the magnet assembly 22 can be embedded in different mounting grooves 2111, respectively, so that the magnets in the magnet assembly 22 can be fixed in the mounting groove 2111, so as to prevent the magnet assembly 22 from falling off the mounting groove 2111 and affecting the normal operation of the motor.
[0070] In the embodiment of the present specification, the number of corresponding mounting grooves 2111 can be set based on the number of magnet assemblies 22. Preferably, the number of magnet assemblies 22 can be 2 groups, and correspondingly, the number of mounting grooves 2111 can be 4. The groove depth of the mounting groove 2111 can be set to 0.7 mm; the distance between the bottom of the mounting groove 2111 and the rotation axis can be set to 2.5 mm; the distance between the outer arc 2211 of the magnet in the magnet assembly 22 and the rotation axis corresponds to 4 mm; it can be understood that the magnet in the magnet assembly 22 is partially exposed outside the mounting groove 2111 to enhance the fit between the rotor assembly 2 and the stator assembly 1.
[0071] In practical applications, the motor can be set in the oral cleaning device, and specifically can be connected to the brush head of the oral cleaning device through the output shaft 212, so that when the rotor assembly 2 reciprocates under the influence of the stator assembly 1, it can drive the brush head of the oral cleaning device to reciprocate, thereby cleaning the teeth at a larger angle, which is beneficial to improving the cleaning angle and the cleaning ability of the oral cleaning device.
[0072] Fig.10 Schematic diagram of the distribution of simulation data of the motor cogging torque in the embodiments of this specification. Fig.11 Schematic diagram of the distribution of simulation data of motor torque in the embodiments of this specification. Fig.10 and Fig.11 The parameters of the test samples are as follows: Fig.10 mid-dash line and Fig.11 Scheme A represented by the dotted line in the figure; the central angle corresponding to the first magnet and the second magnet in the magnet assembly is 49.5°, that is, the central angle corresponding to the outer arc and the inner arc of the first magnet and the second magnet are both 49.5°; the second angle of the interval between the first magnet and the second magnet is 28.5°; the magnet thickness is constructed to be 1.5 mm; the mounting groove depth is constructed to be 0.7 mm; the third angle between the two magnet assemblies is constructed to be 52.5°.
[0073] Fig.10 The solid line and Fig.11In scheme B represented by the solid line in the figure, the central angle corresponding to the first magnet and the second magnet in the magnet assembly is 45°, that is, the central angle corresponding to the outer arc and the inner arc of the first magnet and the second magnet are both 45°; the second angle of the interval between the first magnet and the second magnet is 37°; the magnet thickness is constructed to be 1.5 mm; the mounting groove depth is constructed to be 0.7 mm; the third angle between the two magnet assemblies is constructed to be 53°.
[0074] Fig.10 The dashed line and Fig.11 In scheme C represented by the dotted line, the central angle corresponding to the first magnet and the second magnet in the magnet assembly is 54°, that is, the central angle corresponding to the outer arc and the inner arc of the first magnet and the second magnet are both 54°; the second angle of the interval between the first magnet and the second magnet is 28°; the magnet thickness is constructed to be 1.5 mm; the mounting groove depth is constructed to be 0.7 mm; the third angle between the two magnet assemblies is constructed to be 44°.
[0075] It is understandable that as the rotation angle of the rotor assembly in the motor changes, the cogging torque of the motor will also change. Fig.10 Used to show the relationship between the cogging torque of an electric machine and the rotor components in the electric machine. Fig.10 The horizontal axis in can represent the rotation angle of the rotor assembly in the motor; the vertical axis can represent the cogging torque corresponding to the rotation angle of the rotor assembly.
[0076] For motors used in oral cleaning devices such as electric toothbrushes, the electromagnetic torque and cogging torque resist each other during the motor swing process. By reducing the cogging torque, the swing angle is increased under the same electromagnetic torque, and the resonance point frequency is shifted down. Fig.11 This is the experimental data obtained under a load of 0.5A forward current. The horizontal axis is the rotation angle of the rotor assembly; the vertical axis is the motor torque. Fig.11 Schematic diagram of the motor torque simulation data distribution, Fig.10 It can be seen from the distribution diagram of the illustrated cogging torque simulation data that the zero-position torque of Scheme A is 9.03mN.m, and the NR position is 8.04°; the zero-position torque of Scheme B is 8.23mN.m, and the NR position is 9.71°; the zero-position torque of Scheme C is 9.6mN.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 greatly reduces the cogging torque, and also has a certain impact on the starting torque at the equilibrium position. The NR position angle increases, that is, the position angle where the electromagnetic torque and the cogging torque offset each other to 0, which is conducive to a larger swing angle and a downward shift in the resonant frequency.
[0077] In the embodiment of this specification, when the motor is in a no-load state of I=0A, the rotor is stationary at zero position and there is no output torque. When a positive current is applied, the rotor assembly generates a zero-position torque in the negative direction and rotates in this direction until it reaches the position where the natural return NR output torque is equal to 0Nm, and then shifts to the positive direction. Afterwards, if it is a positive holding current, the rotor assembly 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 can be opposite to the direction of rotation when a positive current is applied, so that the rotor assembly in the motor can reciprocate by applying an alternating current.
[0078] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the figure is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.
[0079] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.
[0080] It should be noted that the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.
[0081] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.
Claims
1. A motor, 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 at least partially arranged in the magnetic field of the stator assembly, the rotor assembly comprising a power shaft and a magnet assembly disposed on the power shaft and cooperating with the stator core; each of the magnet assemblies is configured to include a first magnet and a second magnet arranged circumferentially around the power shaft and cooperating with the same stator core, at least a portion of the first magnet close to the stator core and at least a portion of the second magnet close to the stator core being configured to have different polarities; When in a 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 of the stator core in the radial direction, and the second magnet overlaps with the central projection of the stator core in the radial direction; The ratio of a first central angle corresponding to the overlapping portion of the projection of the first magnet and the stator core to half of a second central angle corresponding to the inner arc of the stator core facing the magnet assembly is in a range of 40% to 70%; and / or, The ratio of the third central angle corresponding to the overlapping portion of the projection of the second magnet and the stator core to half of the second central angle is in a range of 40% to 70%; and / or, The first central angle is the same as the third central angle.
2. The motor according to claim 1, characterized in that In a plane perpendicular to the rotation axis of the rotor assembly, a fourth center angle corresponding to an outer circular arc of the first magnet facing the stator core has a ratio to the second center angle in a range of 60% to 85%; a fifth center angle corresponding to an outer circular arc of the second magnet facing the stator core has a ratio to the second center angle in a range of 60% to 85%.
3. The motor according to claim 1, characterized in that In a plane perpendicular to the axis of rotation of the rotor assembly, the ratio of the arc length of the outer arc of the first magnet facing the stator core to the arc length of the inner arc of the stator core facing the magnet assembly ranges from 60% to 70%; the ratio of the arc length of the outer arc of the second magnet facing the stator core to the arc length of the inner arc of the stator core facing the magnet assembly ranges from 60% to 70%.
4. The motor according to claim 1, characterized in that Among the planes containing the rotation axis of the rotor assembly, at least one plane is a symmetry plane; The stator core is arranged in a mirror-symmetrical manner with the symmetry plane as a reference plane, and / or, The first magnet and the second magnet are arranged in mirror symmetry with the symmetry plane as a reference plane.
5. The motor according to claim 2, characterized in that: The ratio of the first central angle to the fourth central angle is in a range of 30% to 45%; the ratio of the third central angle to the fifth central angle is in a range of 30% to 45%.
6. The motor according to claim 5, characterized in that The ratio of the first central angle to the fourth central angle is in a range of 35% to 40%; the ratio of the third central angle to the fifth central angle is in a range of 35% to 40%.
7. The motor according to claim 1, characterized in that In a plane perpendicular to the rotation axis of the rotor assembly, the first angle between the center line of the first magnet and the center line of the second magnet ranges from 73° to 87°; the center line of the first magnet is a line pointing from the center of the first magnet to the rotation axis, and the center line of the second magnet is a line pointing from the center of the second magnet to the rotation axis.
8. The motor according to claim 1, characterized in that The first magnet and the second magnet are both in the shape of an arc, including an outer arc and an inner arc distributed in the radial direction, and two side edges respectively connecting the corresponding two ends of the outer arc and the inner arc; the central angles of the outer arc and the inner arc are the same.
9. The motor according to claim 8, characterized in that The width of the air gap between the outer arcs of the first magnet and the second magnet and the inner arc of the stator core facing the magnet assembly is in a range of 0.15 mm to 0.25 mm.
10. The motor according to claim 8, characterized in that The thickness of the first magnet and the second magnet are both within a preset thickness range; the preset thickness range is 1 mm to 2 mm; the thickness of the first magnet and the second magnet is the radial distance between the outer arc and the inner arc.
11. The motor according to claim 10, characterized in that The thickness of the first magnet and the second magnet are both 1.5 mm.
12. The motor according to claim 1, characterized in that The first magnet and the second magnet are arranged around the circumference of the power shaft at a preset central angle interval from each other; the preset central angle is a second included angle.
13. The motor according to claim 12, characterized in that The second angle ranges from 23.5° to 38°.
14. The motor according to claim 13, characterized in that The second angle is 28.5°.
15. The motor according to claim 1, characterized in that The motor comprises a motor housing; the rotor assembly is arranged in the motor housing.
16. The motor according to claim 15, characterized in that A limiter is provided on the motor housing; the limiter is used to prevent the rotor assembly from rotating beyond a preset angle threshold.
17. The motor according to claim 1, characterized in that The power shaft includes a rotor core and an output shaft.
18. The motor according to claim 1, characterized in that The power shaft comprises a mounting groove; the mounting groove is used for mounting the magnet assembly.
19. The electric machine according to claim 18, characterized in that The number of the mounting slots is 4.
20. The electric machine according to claim 18, characterized in that The groove depth of the mounting groove is 0.7 mm.
21. The electric machine according to claim 18, characterized in that The magnets in the magnet assembly are embedded in the installation grooves by adhesive.
22. The electric machine according to claim 1, characterized in that The electric machine includes an electromagnetic coil disposed about the stator core that rotates the rotor assembly relative to the stator core about a rotational axis of the rotor assembly in response to a control signal applied to the electromagnetic coil.
23. The electric machine according to claim 22, characterized in that The stator core enables the rotor assembly to rotate unidirectionally around the rotation axis within an angle range of 0° to 20° relative to the stator core; the stator core enables the rotor assembly to rotate bidirectionally around the rotation axis within an angle range of 0° to 40° relative to the stator core.
24. The motor according to any one of claims 1 to 23, characterized in that: There are two stator cores, and the two stator cores are constructed to be symmetrically distributed; there are two magnet assemblies; each magnet assembly corresponds to one stator core; and the third angle between the two magnet assemblies is greater than the second angle between the first magnet and the second magnet in the magnet assembly.
25. The electric machine according to claim 1, characterized in that The frequency range of the motor in the operating state is 100 Hz to 180 Hz.
26. The electric machine according to claim 25, characterized in that The frequency range of the motor in the operating state is 140 Hz to 150 Hz.
27. An oral cleaning device, characterized in that: The oral cleaning device has the motor described in any one of claims 1-26.