Motor and oral cavity cleaning equipment

Abstract

The utility model 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 utility model relates to the technical field of oral cleaning equipment, in particular to a motor used in oral cleaning equipment and an oral cleaning equipment. Background Art

[0002] Oral cleaning devices typically use a motor's output shaft connected to a brush head, driving the brush head to perform cleaning operations when the device is in operation. However, due to the connection between the brush head and the motor's output shaft, the brush head can only rotate within a small, fixed range when subjected to external forces, making it less user-friendly.

[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. Utility Model Content

[0004] This specification proposes a motor applied to an oral cleaning device, and an oral cleaning device to solve the technical problem that 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;

[0006] 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;

[0007] 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;

[0008] The stator core is configured to drive the rotor assembly to reciprocate at a predetermined angle when powered; in a non-powered state, the rotor assembly is configured to rotate at an angle greater than 360° when subjected to an external force;

[0009] 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 configured to return to the balanced position under the action of the cogging torque when the external force is removed.

[0010] 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;

[0011] 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.

[0012] 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.

[0013] 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° to 180°+3°.

[0014] Optionally, the magnet assembly includes a first magnet and a second magnet, and the first magnet and the second magnet are spaced apart and distributed on the power shaft.

[0015] 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 ends of the outer arc and the inner arc.

[0016] Optionally, 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°.

[0017] Optionally, 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 ranges from 73° to 87°; the center line of the first magnet is the center line 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 from the center of the second magnet to the rotation axis.

[0018] Optionally, in a plane perpendicular to the rotation axis of the rotor assembly, the ratio of a first central angle corresponding to an outer arc of the first magnet facing the stator core to a second central angle corresponding to an inner arc of the stator core facing the magnet assembly is in a range of 60% to 85%.

[0019] Optionally, in a plane perpendicular to the rotation axis of the rotor assembly, the ratio of the third central angle corresponding to the outer arc of the second magnet facing the stator core to the second central angle corresponding to the inner arc of the stator core facing the magnet assembly is in a range of 60% to 85%.

[0020] Optionally, the motor further includes an output shaft, one end of which is connected to the brush head of the electric toothbrush.

[0021] The embodiment of this specification also provides an oral cleaning device, which has the motor.

[0022] At least one embodiment of the present invention 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 reset 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

[0023] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 A schematic diagram of the internal structure of a motor provided in an embodiment of this specification;

[0025] Figure 2 A schematic diagram of the overall structure of a motor provided in an embodiment of this specification;

[0026] Figure 3 A schematic diagram of the structure of a power shaft provided in an embodiment of this specification;

[0027] Figure 4 A schematic diagram of a magnet structure provided in an embodiment of this specification;

[0028] Figure 5 A schematic diagram of the first central angle and third central angle structures provided in the embodiments of this specification;

[0029] Figure 6 A schematic diagram of a second angle structure provided in an embodiment of this specification;

[0030] Figure 7 A schematic diagram of the third angle structure provided in the embodiment of this specification;

[0031] Figure 8 A schematic diagram of the fifth angle structure provided in the embodiment of this specification;

[0032] Figure 9 A schematic diagram of the second central angle structure provided in the embodiment of this specification;

[0033] Figure 10 A schematic diagram of the fourth central angle structure provided in the embodiment of this specification;

[0034] Figure 11 A schematic diagram of the distribution of simulation data of the motor cogging torque provided in the embodiments of this specification;

[0035] Figure 12 A distribution diagram of simulation data of motor torque provided by an embodiment of the present specification.

[0036] Reference signs: 1, stator assembly, 11, stator core, 2, rotor assembly, 21, power shaft; 211, rotor core, 2111, mounting groove, 212, output shaft, 22, magnet assembly, 221, first magnet, 2211, outer arc, 2212, inner arc, 2213, side, 222, second magnet, 223, first central angle, 224, second included angle, 225, third included angle, 226, fourth included angle, 227, second central angle, 228, third central angle, 229, fifth included angle, 230, fourth central angle, 231, fifth central angle, 3, motor shell, 4, electromagnetic coil, 5, air gap. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of one or more embodiments of the present specification clearer, the technical scheme of one or more embodiments of the present application will be described clearly and completely below in combination with specific embodiments of the present specification and corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present specification, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of one or more embodiments of the present specification.

[0038] A motor is provided, which can be applied in oral cleaning devices or care devices such as electric toothbrushes, and of course can also be applied in other electronic devices requiring reciprocating swing, which are not listed one by one here. The motor of the present specification can include a motor body, and a stator assembly and a rotor assembly arranged on the motor body.

[0039] The stator assembly is arranged on the motor body and is arranged to generate a magnetic field. 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 pairs, or in two pairs or more pairs; the stator cores are usually arranged uniformly in the circumferential direction of the rotor assembly to facilitate 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 cooperating with the stator core. The rotor assembly can reciprocate at a predetermined angle under the energized state; under the non-energized state, the rotor assembly can rotate more than 360° under the action of external force. The rotor assembly has a balanced position cooperating with the stator core, and an unbalanced position deviating from the stator core; under the action of external force, the rotor assembly can be at the unbalanced position, and under the action of the cogging torque, the rotor assembly can be reset to the balanced position after the external force is removed.

[0040] 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. 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 to 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 the user. In order to solve the defects in the prior art, this solution provides the following embodiments.

[0041] The technical solutions provided by the embodiments of this specification are described in detail below with reference to the accompanying drawings.

[0042] The embodiments of this specification provide a motor for use in an oral cleaning device, so that the oral cleaning device can operate based on the motor to clean teeth and gums and protect oral health.

[0043] Figure 1 This is a schematic diagram of the internal structure of a motor in an embodiment of this specification; Figure 2 This is a schematic diagram of the overall structure of a motor in the 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. An air gap 5 is provided between the rotor assembly 2 and the stator assembly 1.

[0044] The stator assembly 1 can be integrally injection-molded and embedded on both sides of the motor housing 3. The rotor assembly 2 can be installed within the motor housing 3, and the stator assembly 1 and rotor assembly 2 can be coaxially adapted. The stator assembly 1 does not require manual secondary assembly, which allows for a small concentricity tolerance between the stator assembly 1 and the rotor assembly 2. This effectively reduces the cumulative tolerance of the assembled motor, reduces vibration generated by the rotor assembly 2 during rotation, and reduces noise during motor operation. The electromagnetic coil 4 is disposed around the stator core 11 and responds to a control signal applied to the electromagnetic coil 4.

[0045] In the embodiments of this specification, the stator assembly 1 may include one or more pairs of stator cores 11 evenly distributed along the circumference, and electromagnetic coils 4 disposed around the stator cores 11. When the electromagnetic coils 4 are energized, the stator assembly 1 may generate a magnetic field. Specifically, during the energization process, the stator assembly may generate an alternating magnetic field. By varying the magnetic field, the rotor assembly corresponding to the stator cores may be controlled to reciprocate according to the frequency of the changing magnetic field.

[0046] In practical applications, the stator core 11 can be made of high-permeability silicon steel sheets. Silicon steel sheets are an alloy material primarily composed of silicon, carbon, and iron, and possess excellent magnetic permeability and corrosion resistance. In addition to silicon steel sheets, the stator core 11 can also be made of aluminum alloys, copper-nickel alloys, and other materials.

[0047] The rotor assembly 2 may include a power shaft 21 and a magnet assembly 22 circumferentially arranged around the power shaft 21 . The magnet assembly 22 is configured to cooperate with the stator core 11 .

[0048] 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 to working components of an oral cleaning device, such as a toothbrush head or an oral irrigator head, and drive the working components of the oral cleaning device to clean teeth and gums.

[0049] 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 vibrate back and forth at a predetermined angle under the action of the magnetic field generated by the stator assembly 1 being energized, thereby driving the brush head to perform an oral cleaning operation.

[0050] When the stator assembly 1 is in a non-powered state, the rotor assembly 2 can have a balanced position that cooperates with the stator core 11. The rotor assembly 2 can be in a balanced position when it is not subjected to external force; the balanced position can 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 can ensure the normal starting of the motor. In actual applications, the number of balanced positions corresponds to the number of stator cores 11. For example, when the stator assembly 1 only includes a pair of stator cores 11, the rotor assembly 2 can include two balanced positions, and the two balanced positions can be a first balanced position and a second balanced position. Here, the two stator cores in a pair of stator cores 11 can be mirror-symmetrical, and the first angle between the first balanced position and the second balanced position can range from 180°-3° to 180°+3°.

[0051] 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 this 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 with the minimum angle.

[0052] In the embodiments of this specification, since the rotor assembly 2 can rotate to any angle under the action of an external force, the user can manually rotate the brush head to any desired equilibrium position, or to a position near any desired equilibrium position, as needed. For example, when the brush filament area and the electronic display area on the oral cleaning device brush head are on the same side, it can be understood that the rotor assembly 2 is in one of the equilibrium positions. When the rotor assembly is in this equilibrium position, if the user wants to view the information in the electronic display area during brushing, they must first stop brushing and remove the oral cleaning device from the mouth to view it. If the user finds this inconvenient, they can manually rotate the brush head 180° so that the brush filament area and the electronic display area face different sides. The user can then view the prompt information displayed on the electronic display area through a mirror, avoiding the need to stop brushing and not affecting the user's brushing process. This can meet the user's needs and improve the user's convenience in using the oral cleaning device. It can be understood that after the user manually rotates the brush head 180°, the rotor assembly 2 is in another equilibrium position.

[0053] 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 at which the rotor assembly 2 drives the brush head to swing, thereby improving the user's experience of using an oral cleaning device with a motor.

[0054] In the embodiment of this specification, the rotor core 211 is further 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 using an adhesive, wherein the adhesive can be glue or the like. Alternatively, the magnets in the magnet assembly 22 can 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 grooves, thereby preventing the magnet assembly 22 from falling off the mounting groove and affecting the normal operation of the motor.

[0055] 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 two groups, and correspondingly, the number of mounting slots can be four.

[0056] Figure 4 A schematic diagram of a magnet structure provided in an embodiment of this specification; Figure 4 As shown, in the embodiment of this specification, the cross-section of the first magnet 221 and the second magnet 222 can be in the shape of a circular arc. Specifically, the first magnet 221 and the second magnet 222 can each include an outer circular arc 2211 and an inner circular arc 2212 distributed in the radial direction, and two side edges 2213 respectively connecting the two endpoints on the same side of the outer circular arc 2211 and the inner circular arc 2212; the central angle corresponding to the outer circular arc 2211 is the same as the central angle corresponding to the inner circular arc 2212. The central angle corresponding to the outer circular arc 2211 can be the angle between the two first connecting line segments formed by connecting the two endpoints of the outer circular arc 2211 and the center of the power shaft 21 respectively. The central angle corresponding to the inner circular arc 2212 can be the angle between the two second line segments formed by connecting the two endpoints of the inner circular arc 2212 and the center of the power shaft 21 respectively. It is understood 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, helping to generate a more uniform magnetic field distribution, thereby reducing vibration and noise caused by an uneven magnetic field.

[0057] 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, so as to improve the fit between the rotor assembly 2 and the stator assembly 1 without affecting the normal operation of the rotor assembly 2.

[0058] In the embodiments of this 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 radial distance between the outer arc 2211 and the inner arc 2212. It is understood that the radial distance between the outer arc 2211 and the inner arc 2212 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 slot can be set to 0.7 mm; the distance between the bottom of the mounting slot 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 is understood that the magnets in the magnet assembly 22 are partially exposed outside the mounting slot to enhance the fit between the rotor assembly 2 and the stator assembly 1.

[0059] In practical applications, the first magnet 221 and the second magnet 222 can also be constructed with a thickness of 1.2 mm, 1.8 mm, etc. The thickness of the first magnet 221 and the second magnet 222 can be determined based on the spatial distance between the power shaft 21 and the stator assembly 1. An appropriate magnet thickness can be selected to ensure that the magnets 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 magnets meets preset requirements. This can reduce the cogging torque, increase the swing angle, and reduce the frequency without affecting the rotation of the rotor assembly 2.

[0060] Figure 5 This is a schematic diagram of the first center angle and the third center angle structure 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°; they can also be magnets whose central angles corresponding to the outer arc 2211 and the inner arc 2212 are both 45°; they can also be magnets whose central angles corresponding to the outer arc 2211 and the inner arc 2212 are both 54°.

[0061] 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 spacing 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 that are close in distance. The range of the second angle 224 can be 23.5° to 38°. Specifically, the central angle corresponding to the spacing 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 spacing between the first magnet 221 and the second magnet 222 can be reasonably set so that the magnetic field generated by the magnet assembly 22 is more uniform, thereby reducing the cogging torque, thereby increasing the swing angle, and reducing the frequency of the rotor.

[0062] In addition, the fourth angle 226 between the two sets 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. This allows one stator core 11 and one magnet assembly 22 to cooperate with each other, avoiding abnormal effects on adjacent magnet assemblies 22, which could cause the motor to malfunction.

[0063] 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 this specification, within a plane perpendicular to the rotation axis of the rotor assembly 2, the angle between the centerline of the first magnet 221 and the centerline of the second magnet 222 may be a third angle 225. The centerline of the first magnet 221 may be a line extending from the center of the first magnet 221 to the rotation axis; the centerline of the second magnet 222 may be a line extending from the center of the second magnet 222 to the rotation axis. The rotation axis may be the centerline of the power shaft 21, which, as will be understood, is also the centerline of the output shaft 212. The centerline of the first magnet 221 may be perpendicular to the rotation axis; the centerline of the second magnet 222 may also be perpendicular to the rotation axis. The third angle 225 may range from 73° to 87°. Specifically, the third angle 225 may be set to 75°, 79°, 83°, 85°, etc. In actual applications, the value of the third angle 225 may be adjusted based on actual needs and is not specifically limited here.

[0064] 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 this specification, the angle formed by the two outer boundaries of the magnet assembly 2 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 vibrate back and forth; 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 further causing the rotor assembly 2 to be unable to operate normally.

[0065] Figure 9 This is a schematic diagram of the second central angle structure provided in the embodiment of this specification. Figure 9 As shown, in the embodiment of this specification, in a plane perpendicular to the axis of rotation of the rotor assembly 2, the ratio of the first central angle 223 corresponding to the outer arc 2211 of the first magnet 221 facing the stator core 11 to the second central 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 central angle 228 corresponding to the outer arc 2211 of the second magnet 222 facing the stator core 11 to the second central 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 central 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 central angle 223. By setting a reasonable ratio range between the central angle corresponding to the outer arc 2211 of a single magnet and the second central 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.

[0066] 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 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; it may also 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.

[0067] Figure 10 The fourth central angle structure diagram provided in the embodiment of this specification is as follows: Figure 10 As shown, in the embodiment of this specification, when the rotor assembly 2 is in the equilibrium position, the first magnet 221 and the second magnet 222 are respectively located on either side of the stator core 11. The radial center projections of the first magnet 221 and the stator core 11 partially overlap, and the radial center projections of the second magnet 222 and the stator core 11 also partially overlap. The ratio of the fourth central angle 230 corresponding to the overlapping portion of the projections of the first magnet 221 and the stator core 11 to half of the second central angle 227 corresponding to the inner arc of the stator core 11 facing the magnet assembly 22 can be in the range of 40% to 70%. Furthermore, the ratio of the fifth central angle 231 corresponding to the overlapping portion of the projections of the second magnet 222 and the stator core 11 to half of the second central angle 227 corresponding to the inner arc of the stator core 11 facing the magnet assembly 22 can also be in the range of 40% to 70%. Furthermore, the fourth central angle 230 and the fifth central angle 231 are the same. 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.

[0068] 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, so as to improve the fit between the rotor assembly 2 and the stator assembly 1 without affecting the normal operation of the rotor assembly 2.

[0069] As another embodiment, the ratio of the fourth central angle 230 corresponding to the overlapping portion of the projection of the first magnet 221 and the stator core 11 to the first central 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 first ratio can range from 30% to 45%. The ratio of the fifth central angle 231 corresponding to the overlapping portion of the projection of the second magnet 222 and the stator core 11 to the third central 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 second ratio can also range from 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%, and 40% to improve the fit between the stator core 11 and the magnet assembly 22.

[0070] In the embodiments of this specification, the electromagnetic coil 4 can respond to a control signal applied to the electromagnetic coil 4. In this case, the stator core 11 can cause the rotor assembly 2 to rotate relative to the stator core 11 around the rotation axis. The angle range 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 stator core 11 causing the rotor assembly 2 around the rotation axis relative to the stator core 11 can be 0° to 40°. The larger swing angle helps 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 user's prominent toothache, tooth aches, etc. caused by high-frequency vibration, and can also avoid the increase in motor noise caused by high-frequency vibration, which is conducive to improving the user's experience of using an oral cleaning device with such a motor.

[0071] Figure 11 Schematic diagram of the distribution of simulation data of the motor cogging torque in the embodiment of this specification; Figure 12 Schematic diagram of the distribution of simulation data of motor torque in the embodiment of this specification; Figure 11 and Figure 12 The parameters of the test samples are as follows:

[0072] Figure 11 mid-dash line and Figure 12 Scheme A represented by the dotted line in the figure; the central angles corresponding to the first magnet 221 and the second magnet 222 in the magnet assembly are both 49.5°, that is, the central angles corresponding to 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°.

[0073] Figure 11 Solid middle line and Figure 12 Scheme B represented by the solid line in the figure; the central angles corresponding to the first magnet 221 and the second magnet 222 in the magnet assembly are both 45°, that is, the central angles corresponding to 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°.

[0074] Figure 11The dashed line and Figure 12 Scheme C represented by the dotted line in the figure; the central angles corresponding to the first magnet 221 and the second magnet 222 in the magnet assembly are both 54°, that is, the central angles corresponding to 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°.

[0075] 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. Figure 11 Used to illustrate the relationship between the cogging torque of the motor and the rotor assembly 2 in the motor. Figure 11 The horizontal axis in 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.

[0076] For motors used in oral cleaning devices such as electric toothbrushes, the electromagnetic torque and cogging torque act in opposition to each other during the motor's swing. By reducing the cogging torque, the swing angle can be increased under the same electromagnetic torque, while the resonance frequency can be shifted downward. Figure 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. Figure 12 Schematic diagram of the distribution of motor torque simulation data, Figure 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 of 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 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 the current is positive, 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, thereby applying an alternating current to cause the rotor assembly 2 in the motor to reciprocate.

[0078] For ease of description, spatially relative terms such as "above," "above," "on the upper surface of," and "upper" may be used herein to describe the spatial positional relationship of a device or feature to other devices or features as shown in the figures. It should be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, a device described as "above" or "on top of" other devices or structures would then be positioned as "below" or "beneath" the other devices or structures. Thus, the exemplary term "above" can include both the "above" and "below" orientations. The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used herein should be 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, they indicate 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 description 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 foregoing is merely 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 principles of the present application should be included within 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 at a predetermined angle when powered; in a non-powered 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 configured 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 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.

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 2, characterized in that The angle between the first equilibrium position and the second equilibrium position is configured as a first angle, and the range of the first angle is 180°-3° to 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 spaced apart and distributed on the power shaft.

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 ranges from 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 central angle corresponding to an outer arc of the first magnet facing the stator core to a second central 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 central angle corresponding to the outer arc of the second magnet facing the stator core to the second central angle corresponding to 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 further comprises 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 comprises the motor according to any one of claims 1 to 11.

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