Motor and oral cavity cleaning equipment

Abstract

The embodiment of the invention discloses a motor and oral cavity cleaning equipment. The motor comprises a stator assembly and a rotor assembly, the stator assembly comprises at least one pair of stator core bodies; the rotor assembly comprises a power shaft and a magnet assembly; the stator core body can drive the rotor assembly to vibrate in a reciprocating manner in a power-on state; when the stator assembly is not electrified and the rotor assembly is not subjected to external force, the rotor assembly is in the balance position. The rotor assembly is located at an unbalanced position when being subjected to external force, and the rotatable angle of the rotor assembly is larger than 360 degrees when being subjected to the external force; and when the external force is removed, the rotor assembly is reset to the balance position under the action of the cogging torque. Due to the fact that the rotor assembly can rotate by any angle under the action of external force and can reset to the balance position after the external force is removed, a user can manually rotate the brush head connected with the rotor assembly to any needed balance position or the position close to the balance position according to needs, and the convenience of using the oral cavity cleaning equipment by the user is improved.

Description

Technical Field

[0001] The present application relates to the technical field of oral cleaning equipment, and in particular to a motor used in an oral cleaning equipment, and an oral cleaning equipment. Background Art

[0002] Oral cleaning devices usually use the output shaft of a motor to connect to a brush head, so that when the oral cleaning device is running, the brush head is driven to perform a cleaning operation. Since the brush head is connected to the output shaft of the motor, when the brush head is subjected to an external force, it can only rotate within a small fixed range, which is inconvenient for users to use.

[0003] Based on this, how to provide an oral cleaning device that can improve user convenience has become a technical problem that needs to be solved urgently. Summary of the invention

[0004] This specification proposes a motor applied to an oral cleaning device, and an oral cleaning device to solve the technical problem that the existing motors and oral cleaning devices are less convenient for users to use.

[0005] A motor is used in an oral cleaning device, the motor comprising: a stator assembly and a rotor assembly; a stator assembly arranged to generate a magnetic field, wherein the stator assembly comprises at least one pair of stator cores uniformly distributed in a circumferential direction; a rotor assembly at least partially disposed within 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 a stator core; The stator core is configured to drive the rotor assembly to reciprocate and vibrate at a predetermined angle in an energized state; in a non-energized state, the rotor assembly is configured to rotate at an angle greater than 360° when subjected to an external force; The rotor assembly has a balanced position matched with the stator core and an unbalanced position deviating from the stator core; in the unbalanced position, the rotor assembly is constructed to return to the balanced position under the action of the cogging torque when the external force is removed.

[0006] Optionally, the number of the equilibrium positions is configured to correspond to the number of the stator cores; the equilibrium positions include at least a first equilibrium position and a second equilibrium position corresponding to a pair of stator cores respectively; When in the non-equilibrium position, the magnet assembly is configured to reset toward the first equilibrium position or the second equilibrium position with the minimum angle according to the angle between the current position and the first equilibrium position or the second equilibrium position.

[0007] Optionally, the stator assembly includes two stator cores, and the two stator cores are mirror-symmetrical; the rotor assembly includes two groups of magnet assemblies, and the two groups of magnet assemblies are mirror-symmetrical.

[0008] Optionally, the angle between the first equilibrium position and the second equilibrium position is constructed as a first angle, and the range of the first angle is 180°-3°~180°+3°.

[0009] Optionally, the magnet assembly includes a first magnet and a second magnet, and the first magnet and the second magnet are distributed on the power shaft with an interval.

[0010] Optionally, the first magnet and the second magnet are both in an arc shape, including an outer arc and an inner arc distributed in the radial direction, and two side edges respectively connecting the two ends of the outer arc and the inner arc.

[0011] Optionally, the first magnet and the second magnet are arranged circumferentially around the power shaft, and a central angle corresponding to the interval between the first magnet and the second magnet is a second angle; the range of the second angle is 23.5° to 38°.

[0012] Optionally, in a plane perpendicular to the rotation axis of the rotor assembly, a third angle between a center line of the first magnet and a center line of the second magnet ranges from 73° to 87°; the center line of the first magnet is a center line pointing from the center of the first magnet to the rotation axis of the rotor assembly, and the center line of the second magnet is a center line pointing from the center of the second magnet to the rotation axis.

[0013] Optionally, in a plane perpendicular to the rotation axis of the rotor assembly, the ratio of a first center angle corresponding to an outer arc of the first magnet facing the stator core to a second center angle corresponding to an inner arc of the stator core facing the magnet assembly is in a range of 60% to 85%.

[0014] Optionally, in a plane perpendicular to the rotation axis of the rotor assembly, the ratio of a third center angle corresponding to an outer arc of the second magnet facing the stator core to a second center angle corresponding to an inner arc of the stator core facing the magnet assembly is in a range of 60% to 85%.

[0015] Optionally, the motor further includes an output shaft, one end of which is connected to the brush head of the electric toothbrush.

[0016] The embodiment of the present specification also provides an oral cleaning device, and the oral cleaning device has the motor.

[0017] At least one embodiment of the present specification can achieve the following beneficial effects: by allowing the rotor assembly to rotate to any angle under the action of an external force and to return to a balanced position after the external force is removed, the user can manually rotate the brush head connected to the rotor assembly to any desired balanced position or near the balanced position as needed, thereby improving the convenience of the user in using the oral cleaning device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] 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 application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] 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 a power shaft provided in an embodiment of this specification; Figure 4 A schematic diagram of a magnet structure provided in an embodiment of this specification; Figure 5 A schematic diagram of the first center angle and the third center angle structure provided in the embodiments of this specification; Figure 6 A schematic diagram of a second angle structure provided in an embodiment of this specification; Figure 7 A schematic diagram of a third angle structure provided in an embodiment of this specification; Figure 8 A schematic diagram of the fifth angle structure provided in the embodiment of this specification; Fig. 9 A schematic diagram of the second central angle structure provided in the embodiment of this specification; Fig.10 A schematic diagram of the fourth central angle structure provided in the embodiment of this specification; Fig.11 A schematic diagram of the distribution of simulation data of the motor cogging torque provided in the embodiments of this specification; Fig.12 A schematic diagram of the distribution of simulation data of motor torque provided in an embodiment of this specification.

[0020] 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 angle, 225. third angle, 226. fourth angle, 227. second center angle, 228. third center angle, 229. fifth angle, 230. fourth center angle, 231. fifth center angle, 3. motor housing, 4. electromagnetic coil, 5. air gap. DETAILED DESCRIPTION

[0021] 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 application 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 application, not all of them. 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.

[0022] A motor is provided, which can be used in oral cleaning devices or care devices such as electric toothbrushes, and can also be used in other electronic devices that require reciprocating swings, which are not listed here. The motor of the embodiment of this specification may include a motor body, and a stator assembly and a rotor assembly arranged on the motor body.

[0023] 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 pair of stator cores, which can be fixed on the motor body to provide a magnetic field for the motor. The stator cores can be arranged in a pair, or in two or more pairs; the stator cores are usually evenly arranged in the circumferential direction of the rotor assembly to facilitate the reciprocating swing of the rotor assembly, etc. The rotor assembly can include a power shaft and a magnet assembly arranged on the power shaft and matched with the stator core. In the energized state, the rotor assembly can reciprocate at a predetermined angle; in the non-energized state, the rotor assembly can rotate at an angle greater than 360° when subjected to external force. The rotor assembly has a balanced position matched with the stator core, and an unbalanced position deviating from the stator core; the rotor assembly can be in an unbalanced position under the action of an external force, and the rotor assembly can be reset to a balanced position under the action of the cogging torque after the external force is removed.

[0024] In the prior art, with the development of the industry, an electronic display area can be provided on the handle of the oral cleaning device, and the electronic display area can be used to display some prompt information about the user's oral cleaning status, such as missed brushing prompt information, overpressure prompt information, brushing time prompt information, etc., to remind the user. At present, the brush head of the oral cleaning device can only sweep or rotate within a fixed range, so that the direction of the brush wire area on the brush head is fixed with the direction of the electronic display area. For example, the direction of the brush wire area and the electronic display area can be on the same side. At this time, if the user wants to view the prompt information in the electronic display area during the oral cleaning process, he needs to stop brushing to view it, which is less convenient for users. In order to solve the defects in the prior art, this solution provides the following embodiments.

[0025] The technical solutions provided by the embodiments of this specification are described in detail below in conjunction with the accompanying drawings.

[0026] The embodiments of this specification provide a motor for use in 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.

[0027] Figure 1 This is a schematic diagram of the internal structure of a motor in an embodiment of this specification; Figure 2 FIG. 1 is a schematic diagram of the overall structure of a motor in an embodiment of this specification. Figure 1 and Figure 2 As shown, the motor may include a stator assembly 1, a rotor assembly 2, a motor housing 3, and an electromagnetic coil 4. There is an air gap 5 between the rotor assembly 2 and the stator assembly 1.

[0028] The stator assembly 1 can be integrally injection molded and embedded on both sides of the motor housing 3, and the rotor assembly 2 can be installed in the motor housing 3, and the stator assembly 1 and the rotor assembly 2 can 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 can be small, which can effectively reduce the cumulative tolerance of the assembled motor, reduce the vibration generated by the rotor assembly 2 when rotating, and reduce the noise when the motor is running. The electromagnetic coil 4 is arranged around the stator core 11, in response to the control signal applied to the electromagnetic coil 4.

[0029] In the embodiment of this specification, the stator assembly 1 may include one or more pairs of stator cores 11 evenly distributed in the circumferential direction, and an electromagnetic coil 4 arranged around the stator core 11. When the electromagnetic coil 4 is energized, the stator assembly 1 may generate a magnetic field. Specifically, the stator assembly may generate an alternating magnetic field during the energization process, and the rotor assembly corresponding to the stator core may be controlled to reciprocate according to the frequency of the change of the magnetic field by changing the magnetic field.

[0030] 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.

[0031] The rotor assembly 2 may include a power shaft 21 and a magnet assembly 22 circumferentially arranged around the power shaft 21 , wherein the magnet assembly 22 is disposed in cooperation with the stator core 11 .

[0032] Figure 3 The schematic diagram of the structure of the power shaft provided in the embodiment of this specification is as follows: Figure 3 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 with working parts of an oral cleaning device, such as a toothbrush head and an oral irrigator head, and drive the working parts of the oral cleaning device to clean teeth and gums.

[0033] The rotor assembly 2 is at least partially located in the magnetic field generated by the stator assembly 1, so that the rotor assembly 2 can reciprocate at a predetermined angle under the action of the magnetic field generated by the stator assembly 1 when it is energized, thereby driving the brush head to perform an oral cleaning operation.

[0034] 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 rotor assembly being in a 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, and the two balanced positions may be a first balanced position and a second balanced position, respectively. Here, the two stator cores 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°.

[0035] In addition, when the rotor assembly 2 is subjected to an external force, the rotor assembly 2 can also be in an unbalanced position under the action of the external force. No limiting structure is provided in the motor of the embodiment of the present specification, 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 unbalanced 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.

[0036] In the embodiment of this specification, since the rotor assembly 2 can rotate at any angle under the action of external force, the user can manually rotate the brush head to any desired balance position as needed, or manually rotate the brush head to the vicinity of any desired balance position; for example, when the brush wire area on the brush head of the oral cleaning device is on the same side as the electronic display area, it can be understood that the rotor assembly 2 is located at one of the balance positions at this time. When the rotor assembly is in this balance position, during the brushing process, if the user wants to view the information in the electronic display area, he can only stop the brushing operation first and take the oral cleaning device out of the mouth to view it. If the user finds it inconvenient, the brush head can be manually rotated 180°, so that the brush wire area and the electronic display area face different sides. At this time, the user can view the prompt information displayed in the electronic display area from the mirror to avoid the user stopping brushing, without affecting the user's brushing process, thereby meeting the user's needs and improving the convenience of the user using 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 balance position.

[0037] In the embodiment of this specification, the rotor assembly 2 may include two groups of magnet assemblies 22, and the two groups of magnet assemblies 22 may be mirror-symmetrical. Any group of magnet assemblies 22 may include a first magnet 221 and a second magnet 222, and the first magnet 221 and the second magnet 222 may be distributed at intervals on the power shaft 21. Specifically, the first magnet 221 and the second magnet 222 may be distributed at intervals on the rotor core 211 of the power shaft 21, so that the magnetic field distribution on the rotor assembly 2 is more uniform, thereby reducing the cogging torque. When the motor output torque remains unchanged, the swing angle can be increased to extend the driving time of a single cycle, thereby reducing the frequency of the rotor assembly 2 driving the brush head to swing, and improving the user's experience of using an oral cleaning device with a motor.

[0038] In the embodiment of this specification, the rotor core 211 is also provided with a mounting groove 2111 for mounting the magnet assembly 22. Specifically, the magnets in the magnet assembly 22 can be embedded in the mounting groove by an adhesive, wherein the adhesive can be glue or the like. The magnets in the magnet assembly 22 can also be placed in the mounting groove by welding. The first magnet 221 and the second magnet 222 in the magnet assembly 22 can be embedded in different mounting grooves respectively, so that the magnets in the magnet assembly 22 can be fixed in the mounting groove to prevent the magnet assembly 22 from falling off the mounting groove and affecting the normal operation of the motor.

[0039] In the embodiment of this specification, the number of corresponding mounting slots 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 slots can be 4.

[0040] Figure 4 A schematic diagram of a magnet structure provided in an embodiment of this specification; Figure 4 As shown, in the embodiment of the present specification, the cross-section of the first magnet 221 and the second magnet 222 may be in the shape of an arc. Specifically, the first magnet 221 and the second magnet 222 may include an outer arc 2211 and an inner arc 2212 distributed in the radial direction, and two side edges 2213 respectively connecting the two end points on the same side of the outer arc 2211 and the inner arc 2212; the central angle corresponding to the outer arc 2211 is the same as the central angle corresponding to the inner arc 2212. The central angle corresponding to the outer arc 2211 may be the angle between the two first connecting line segments formed by connecting the two end points of the outer arc 2211 with the center of the power shaft 21 respectively. The central angle corresponding to the inner arc 2212 may be the angle between the two second line segments formed by connecting the two end points of the inner arc 2212 with the center of the power shaft 21 respectively. It is understandable that the two first connecting line segments and the two side edges 2213 may have overlapping portions, and the two second connecting line segments and the two side edges 2213 may also have overlapping portions. The arc-shaped magnet shape can better match the shape of the air gap 5 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.

[0041] In the actual process of constructing the motor, the width range of the air gap 5 between the outer arc 2211 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.

[0042] 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. The depth of the mounting groove can be set to 0.7 mm; the distance between the bottom of the mounting groove 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 is 4 mm; it can be understood that the magnet in the magnet assembly 22 is partially exposed outside the mounting groove to enhance the fit between the rotor assembly 2 and the stator assembly 1.

[0043] In practical applications, the first magnet 221 and the second magnet 222 can also be constructed to have 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 can have a certain gap with the stator assembly after being arranged on the power shaft, and the magnetic field generated by the magnet can meet the preset requirements, so that the cogging torque can be reduced, the swing angle can be increased, and the frequency can be reduced without affecting the rotation of the rotor assembly 2.

[0044] Figure 5 The first center angle and the third center angle structure diagram provided in the embodiment of this specification. Figure 5 As shown, in the embodiment of the present specification, the central angle corresponding to the outer arc 2211 of the first magnet 221 and the central angle corresponding to the inner arc 2212 can be a first central angle 223, and the angle range of the first central angle 223 can be 42° to 57°; the central angle corresponding to the outer arc 2211 of the second magnet 222 and the central angle corresponding to the inner arc 2212 can be a third central angle 228, and the angle range of the third central angle 228 can be 42° to 57°. Specifically, the first magnet 221 and the second magnet 222 can both be magnets whose central angles corresponding to the outer arc 2211 and the inner arc 2212 are both 49.5°; or they can both be magnets whose central angles corresponding to the outer arc 2211 and the inner arc 2212 are both 45°; or they can both be magnets whose central angles corresponding to the outer arc 2211 and the inner arc 2212 are both 54°.

[0045] Figure 6 This is a schematic diagram of the second angle structure provided in the embodiment of this specification. Figure 6 As shown, in the embodiment of this specification, the central angle corresponding to the circumferential interval between the first magnet 221 and the second magnet 222 on the power shaft 21 can be a second angle 224, and the second angle 224 can be the angle between the first connecting line segment and the second connecting line segment with a similar distance. The range of the second angle 224 can be 23.5° to 38°. Specifically, the central angle corresponding to the interval between the first magnet 221 and the second magnet 222 in a group of magnet assemblies 22 can be 25°, 27°, 30.5°, 34.4°, etc. 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, thereby increasing the swing angle, and reducing the frequency of the rotor.

[0046] In addition, the fourth angle 226 between the two groups of magnet assemblies 22 can be greater than the second angle 224 between the first magnet 221 and the second magnet 222 in the magnet assembly 22. Thus, a stator core 11 and a magnet assembly 22 can cooperate with each other to avoid abnormal effects on adjacent magnet assemblies 22, which may cause the motor to fail to operate normally.

[0047] Figure 7 This is a schematic diagram of the third angle structure provided in the embodiment of this specification. Figure 7 As shown, in the embodiment of the present specification, in a plane perpendicular to the rotation axis of the rotor assembly 2, the angle between the center line of the first magnet 221 and the center line of the second magnet 222 can be a third angle 225. Among them, the center line of the first magnet 221 can be a line from the center of the first magnet 221 to the rotation axis; the center line of the second magnet 222 can be a line from the center of the second magnet 222 to the rotation axis. The rotation axis can 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 can be perpendicular to the rotation axis; the center line of the second magnet 222 can also be perpendicular to the rotation axis. The range of the third angle 225 can be 73° to 87°. Specifically, the third angle 225 can be set to 75°, 79°, 83°, 85°, etc. In practical applications, the size of the third angle 225 can also be set based on actual needs, and no specific limitation is made here.

[0048] Figure 8 This is a schematic diagram of the fifth angle structure provided in the embodiment of this specification. Figure 8As shown, in the embodiment of the present specification, the angle formed by the two outer boundaries of the magnet assembly 22 extending to the rotation axis of the rotor assembly 2 can be a fifth angle 229, and the fifth angle 229 can range from 122° to 141°. Specifically, the fifth angle 229 can be 127°, 127.5° or 136°. The above angle range can make a group of magnet assemblies 22 occupy a more reasonable proportion on the power shaft 21, avoiding a group of magnet assemblies 22 occupying too large a proportion of the power shaft 21, thereby causing the rotor assembly 2 to be unable to reciprocate; at the same time, avoid a group of magnet assemblies 22 occupying too small a proportion of the power shaft 21, thereby reducing the degree of fit between the rotor assembly 2 and the stator assembly 1, and then causing the rotor assembly 2 to be unable to operate normally.

[0049] Fig. 9 This is a schematic diagram of the second central angle structure provided in the embodiment of this specification. Fig. 9 As shown, in the embodiment of the present specification, in a plane perpendicular to the axis of rotation of the rotor assembly 2, the ratio of the first center angle 223 corresponding to the outer arc 2211 of the first magnet 221 facing the stator core 11 to the second center angle 227 corresponding to the inner arc of the stator core 11 facing the magnet assembly 22 can be in the range of 60% to 85%; the ratio of the third center angle 228 corresponding to the outer arc 2211 of the second magnet 222 facing the stator core 11 to the second center angle 227 corresponding to the inner arc of the stator core 11 facing the magnet assembly 22 can also be in the range of 60% to 85%. In addition, when the second magnet 222 and the first magnet 221 have the same shape, size and structure, the size of the third center angle 228 corresponding to the outer arc 2211 of the second magnet 222 facing the stator core 11 is the same as the size of the first center angle 223. By setting a reasonable ratio range between the center angle corresponding to the outer arc 2211 of a single magnet and the second center angle 227 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.

[0050] In practical applications, the cogging torque can also be reduced and the swing angle can be increased by setting a reasonable ratio range of the arc length of the outer arc 2211 of a single magnet to the arc length of the inner arc of the stator core 11. Specifically, in a plane perpendicular to the axis of rotation of the rotor assembly 2, the ratio range of the arc length of the outer arc 2211 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 can be set to 60% to 70%; the ratio range of the arc length of the outer arc 2211 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 can also be set to 60% to 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; or it may not include the chamfered portion of the stator core 11, and the specific situation can be set based on the actual structural requirements of the motor.

[0051] Fig.10 The fourth central angle structure diagram provided in the embodiment of this specification is as follows: Fig.10 As shown, in the embodiment of the present specification, when the rotor assembly 2 is in the equilibrium position, the first magnet 221 and the second magnet 222 are respectively located on both sides of the stator core 11, and the first magnet 221 and the central projection of the stator core 11 in the radial direction have a partial overlapping area, and the second magnet 222 and the central projection of the stator core 11 in the radial direction also have a partial overlapping area. Among them, the ratio range of the fourth center angle 230 corresponding to the overlapping part of the projection of the first magnet 221 and the stator core 11 to half of the second center angle 227 corresponding to the inner arc of the stator core 11 facing the magnet assembly 22 can be 40% to 70%; and / or, the fifth center angle 231 corresponding to the overlapping part of the projection of the second magnet 222 and the stator core 11 to half of the second center angle 227 corresponding to the inner arc of the stator core 11 facing the magnet assembly 22 can also be 40% to 70%. And / or, the fourth center angle 230 is the same as the fifth center angle 231. The central projection may be a projection of the first magnet 221 , the second magnet 222 and the stator core 11 with a point on the rotation axis as the projection center when the rotor assembly 2 is in a balanced position.

[0052] In the actual process of constructing the motor, the width range of the air gap 5 between the outer arc 2211 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.

[0053] As another embodiment, the ratio of the fourth center angle 230 corresponding to the overlapping portion of the projection of the first magnet 221 and the stator core 11 to the first center angle 223 corresponding to the outer arc 2211 of the first magnet 221 facing the stator core 11 can be a first ratio, and the range of the first ratio can be 30% to 45%. The ratio of the fifth center angle 231 corresponding to the overlapping portion of the projection of the second magnet 222 and the stator core 11 to the third center angle 228 corresponding to the outer arc 2211 of the second magnet 222 facing the stator core 11 can be a second ratio, and the range of the second ratio can also be 30% to 45%. In addition, when the second magnet 222 and the first magnet 221 have the same shape, size and structure, and the first magnet 221 and the second magnet 222 are symmetrically arranged along the horizontal axis, the size of the fifth central angle 231 is the same as the size of the fourth central angle 230, and the first ratio is also the same as the second ratio. The above-mentioned first ratio and second ratio can be values ​​such as 35%, 37%, 40%, etc., to improve the fit between the stator core 11 and the magnet assembly 22.

[0054] In the embodiment of the present specification, the electromagnetic coil 4 can respond to the control signal applied to the electromagnetic coil 4, and at this time, the stator core 11 can make the rotor assembly 2 rotate relative to the stator core 11 around the rotation axis. The angle range of the unidirectional rotation of the rotor assembly 2 around the rotation axis relative to the stator core 11 can be 0° to 20°; correspondingly, the angle range of the bidirectional rotation of the rotor assembly 2 around the rotation axis relative to the stator core 11 by the stator core 11 can be 0° to 40°. A swing angle with a large amplitude helps to meet the tooth cleaning needs of different consumers. In addition, the frequency range of the motor in the operating state is 100 Hz to 180 Hz; it can further be stabilized to operate normally between 140 Hz and 150 Hz. Reducing the vibration frequency of the motor can avoid the situation where the user has prominent feelings such as toothache and tooth acid 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.

[0055] Fig.11 Schematic diagram of distribution of simulation data of motor cogging torque in the embodiment of this specification; Fig.12 Schematic diagram of distribution of simulation data of motor torque in the embodiment of this specification; Fig.11 and Fig.12 The parameters of the test samples are as follows: Fig.11 mid-dash line and Fig.12 Scheme A represented by the dotted line in the figure; the central angles of the first magnet 221 and the second magnet 222 in the magnet assembly are both 49.5°, that is, the central angles of the outer arc 2211 and the inner arc 2212 of the first magnet 221 and the second magnet 222 are both 49.5°; the second angle 224 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 fourth angle 226 between the two magnet assemblies 22 is constructed to be 52.5°.

[0056] Fig.11 The solid line and Fig.12 Scheme B represented by the solid line in the figure; the central angles of the first magnet 221 and the second magnet 222 in the magnet assembly are both 45°, that is, the central angles of the outer arc 2211 and the inner arc 2212 of the first magnet 221 and the second magnet 222 are both 45°; the second angle 224 of the interval between the first magnet 221 and the second magnet 222 is 37°; the magnet thickness is constructed to be 1.5 mm; the mounting groove depth is constructed to be 0.7 mm; the fourth angle 226 between the two magnet assemblies 22 is constructed to be 53°.

[0057] Fig.11 The dashed line and Fig.12 Scheme C represented by the dotted line in the figure; the central angles of the first magnet 221 and the second magnet 222 in the magnet assembly are both 54°, that is, the central angles of the outer arc 2211 and the inner arc 2212 of the first magnet 221 and the second magnet 222 are both 54°; the second angle 224 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 mounting groove depth is constructed to be 0.7 mm; the angle of the fourth angle 226 between the two magnet assemblies 22 is constructed to be 44°.

[0058] It is understandable that as the rotation angle of the rotor assembly 2 in the motor changes, the cogging torque of the motor will also change. Fig.11 Used to illustrate the relationship between the cogging torque of the motor and the rotor assembly 2 in the motor. Fig.11 The horizontal axis in 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.

[0059] 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.12 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 can be the motor torque. Fig.12 Schematic diagram of the motor torque simulation data distribution, Fig.11 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.

[0060] 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 2 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 2 can be opposite to the direction of rotation when a positive current is applied, so that the rotor assembly 2 in the motor can reciprocate by applying an alternating current.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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, used in an oral cleaning device, characterized in that: The motor comprises: a stator assembly and a rotor assembly; a stator assembly arranged to generate a magnetic field, wherein the stator assembly comprises at least one pair of stator cores uniformly distributed in a circumferential direction; a rotor assembly at least partially disposed within 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 a stator core; The stator core is configured to drive the rotor assembly to reciprocate and vibrate at a predetermined angle in an energized state; in a non-energized state, the rotor assembly is configured to rotate at an angle greater than 360° when subjected to an external force; The rotor assembly has a balanced position matched with the stator core and an unbalanced position deviating from the stator core; in the unbalanced position, the rotor assembly is constructed to return to the balanced position under the action of the cogging torque when the external force is removed.

2. The motor according to claim 1, characterized in that The number of the balancing positions is configured to correspond to the number of the stator cores; the balancing positions include at least a first balancing position and a second balancing position corresponding to a pair of stator cores respectively; When in the non-equilibrium position, the magnet assembly is configured to reset toward the first equilibrium position or the second equilibrium position with the minimum angle according to the angle between the current position and the first equilibrium position or the second equilibrium position.

3. The motor according to claim 1, characterized in that The stator assembly includes two stator cores, and the two stator cores are mirror-symmetrical; the rotor assembly includes two groups of magnet assemblies, and the two groups of magnet assemblies are mirror-symmetrical.

4. The motor according to claim 1, characterized in that The angle between the first equilibrium position and the second equilibrium position is constructed as a first angle, and the range of the first angle is 180°-3°~180°+3°.

5. The motor according to claim 1, characterized in that The magnet assembly includes a first magnet and a second magnet, and the first magnet and the second magnet are distributed on the power shaft with an interval.

6. The motor according to claim 5, characterized in that The first magnet and the second magnet are both in an arc shape, including an outer arc and an inner arc distributed in the radial direction, and two side edges respectively connecting the two ends of the outer arc and the inner arc.

7. The motor according to claim 6, characterized in that The first magnet and the second magnet are arranged circumferentially around the power shaft, and the central angle corresponding to the interval between the first magnet and the second magnet is a second angle; the range of the second angle is 23.5° to 38°.

8. The motor according to claim 6, characterized in that In a plane perpendicular to the rotation axis of the rotor assembly, the third angle between the center line of the first magnet and the center line of the second magnet is in the range of 73° to 87°; the center line of the first magnet is the center line pointing from the center of the first magnet to the rotation axis of the rotor assembly, and the center line of the second magnet is the center line pointing from the center of the second magnet to the rotation axis.

9. The motor according to claim 6, characterized in that In a plane perpendicular to the rotation axis of the rotor assembly, a ratio of a first center angle corresponding to an outer arc of the first magnet facing the stator core to a second center angle corresponding to an inner arc of the stator core facing the magnet assembly is in a range of 60% to 85%.

10. The motor according to claim 6, characterized in that In a plane perpendicular to the rotation axis of the rotor assembly, the ratio of the third center angle of the second magnet corresponding to the outer arc of the stator core facing the stator core to the second center angle of the inner arc of the stator core facing the magnet assembly is in a range of 60% to 85%.

11. The motor according to claim 2, characterized in that The motor also includes an output shaft, one end of which is connected to the brush head of the electric toothbrush.

12. An oral cleaning device, characterized in that: The oral cleaning device has the motor according to any one of claims 1-11.

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