JP3204771U - Actuator and its motor - Google Patents

Abstract

An electric motor having a small cogging torque and thus low vibration and noise, and an actuator using such a motor are provided. The actuator includes a motor and a transmission. The motor includes a stator and a rotor. The stator includes a housing and a permanent magnet fixed to the inner wall surface of the housing. The permanent magnet has four magnetic poles. The rotor has a shaft and a core fixed to the shaft. The core includes an attachment portion that is sleeve-fitted to the shaft and teeth that extend outward from the attachment portion. A coil is wound around the teeth. Each tooth includes a winding portion extending from the attachment portion and a pole portion provided at an end of the winding portion. Adjacent pole portions are spaced apart from each other to form a slot opening. The outer surface of each pole portion facing the magnet has at least one groove to reduce cogging torque. [Selection] Figure 1

Description

[0002]
The present invention relates to an actuator for a vehicle sunroof, and more particularly to an electric motor for the actuator.

[0003]
The sunroof is a general part for ventilating the vehicle, and is generally divided into an electric type and a manual type. The electric sunroof is driven by an actuator including an electric motor and a transmission. Usually, the motor is a direct current permanent magnet motor having a stator including a permanent magnet and a rotor including an iron core. The core includes several pole teeth. A rotor winding is wound around the pole teeth, and the winding is energized to generate a magnetic field that interacts with the magnetic field of the permanent magnet to rotate the rotor. A known permanent magnet motor rotor includes six pole teeth, and winding slots are formed between adjacent pole teeth. Such a motor generates a large cogging torque and a large torque ripple, resulting in vibration and noise. Therefore, the use of this motor affects the user's comfort.

[0004]
Therefore, an electric motor having a low cogging torque and thus low vibration and noise, and an actuator using such a motor are desired.

[0005]
Accordingly, in one aspect, the present invention provides a permanent magnet motor including a stator and a rotor disposed in the stator, and the stator is fixed to a housing and an inner wall of the housing. The permanent magnet has four magnetic poles, the rotor includes a rotor shaft and a rotor core fixed to the rotor shaft, and the rotor core is fitted into the rotor shaft by a sleeve. A mounting portion, ten teeth extending outward from the mounting portion, and a plurality of coils wound around the teeth, each of the teeth being wound from the mounting portion. A pole portion provided at the end of the winding portion, and adjacent pole portions are spaced apart from each other in the circumferential direction to form a slot opening, and each pole portion facing the permanent magnet External surface is axial Having extending grooves.

[0006]
The width of the groove is preferably equal to or less than the width of the slot opening.

[0007]
In the circumferential direction, the width of the pole portion is preferably larger than the width of the slot opening.

[0008]
A part of the surface of the pole part where the groove is provided is an imaginary part, a part of the surface of the pole part where the groove is not provided is a real part, and the width of the imaginary part is It is preferable that the width of the real part is approximately the same.

[0009]
Two grooves are provided in the pole part, the two grooves divide the pole part into two imaginary parts and three real parts, and the two imaginary parts and the three real parts are: It is preferable that they are arranged alternately.

[0010]
The rotor further includes a commutator fixed to the rotor shaft, and the commutator includes a base that is sleeve-fitted to the rotor shaft in a fixed state, and a plurality of commutator bars fixed to the base. A hook is provided at one end of each commutator rod facing the rotor core, each hook is connected to a respective coil, and the stator is further in sliding electrical contact with the commutator rod. It is preferred to have a pair of brushes arranged.

[0011]
The housing has an open end and a closed end, and an end cap is coupled to the open end, the end cap extending from the cap plate, and a cap plate configured to close the open end Preferably, the cylindrical body is configured to be inserted into the housing as an interference fit, and a plurality of protruding ribs are formed on the outer wall surface of the cylindrical body.

[0012]
The permanent magnet is preferably formed by a plurality of separate permanent magnet segments.

[0013]
In a second aspect, the present invention provides an actuator comprising a motor and a transmission connected to the motor and gearing down the motor, wherein the motor is the permanent magnet motor described above. One end of the rotor shaft of the motor extends from the motor to drive the gear train of the transmission.

[0014]
The transmission includes a shell, a worm and drive gear accommodated in the shell, and an output gear provided outside the shell, and the worm is drivably coupled to the rotor shaft of the motor, Meshed with the drive gear, the drive gear is fixed to a rotation shaft of the actuator, the rotation shaft of the actuator extends from the shell, one end rotatably connected to the shell, It is preferable to have the other end fixedly connected to the output gear, and to rotate the output gear together with the drive gear.

It is a perspective view of an actuator concerning this application. FIG. 2 is a partial view of the actuator shown in FIG. 1, showing a gear train with a part of the shell of the transmission removed. It is a perspective view of the permanent magnet motor of an actuator. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. FIG. 5 is a cross-sectional view taken along line VV in FIG. 3. FIG. 4 is a cross-sectional view taken along line VI-VI in FIG. 3.

[0015]
Preferred embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings. In the figures, identical structures, elements or components that appear in more than one figure are generally labeled with the same reference sign in all the figures in which they appear. The dimensions of the components and structures shown in the figures are generally chosen for convenience and clarity of presentation and are not necessarily to scale.

[0022]
As shown in FIG. 1, the actuator according to the present application includes a motor 10 and a transmission 30 connected to the motor 10. The transmission has a step-down, that is, a reduction gear train, and reduces the rotational speed of the motor when driving a load, for example, when opening and closing a sunroof of a vehicle. The transmission has a shell 32 that houses a gear train.

[0023]
Referring to FIG. 2, the gear train includes a worm 34, a drive gear 36 (a worm wheel shape), and an output gear 38. The worm 34 and the drive gear 36 are accommodated in the shell 32, and the output gear 38 is disposed outside the shell 32 and is configured to be coupled to a load. The size of the output gear 38 is much smaller than the size of the drive gear 36. The worm 34 is driven by the motor 10, has one end connected to the shaft of the motor 10, and meshes with a large gear 36. As an alternative, the worm can be formed directly on the motor shaft. The drive gear 36 is fixed to the rotary shaft 40, and the rotary shaft 40 has one end rotatably connected to the shell 32 and the other end that passes through the shell 32 and is fixedly connected to the output gear 38. Thus, when the drive gear 36 is driven by the worm 34, it rotates together with the output gear 38 to constitute a further speed reduction mechanism. Therefore, the rotational speed of the output from the transmission 30 is much lower than the rotational speed of the motor 10.

[0024]
3 to 6, the motor 10 is a permanent magnet motor including a stator 11 and a rotor 12 accommodated in the stator 11. The stator 11 includes a housing 13, an end cap 14 connected to the housing 13, a permanent magnet 15 fixed to the inside of the housing 13, and an electric brush 16 fixed to the inside of the end cap 14. The rotor 12 includes a rotor shaft 17, an iron core 18 and a commutator 19 that are sleeve-fitted to the rotor shaft 17, and windings that are wound around the core 18 and electrically connected to the commutator 19 (see FIG. Not shown). The core 18 is disposed at a position corresponding to the permanent magnet 15 in the axial direction, and the commutator 19 is disposed at a position corresponding to the brush 16 in the axial direction. The commutator 19 interacts with the brush 16 to connect the windings to the power source so that the rotor can generate a variable magnetic field. The magnetic field or rotor interacts with the magnetic field of the stator 11 to rotate the rotor 12. In this embodiment, the motor 10 is a motor having four stator poles and ten slots 185 (which form ten rotor poles). The stator magnetic field has four poles produced by permanent magnets. In this embodiment, the permanent magnet 15 is formed by four individual segments, each segment generating a magnetic pole. As an alternative, the permanent magnet can be constructed in one piece or in any number of members or segments to form the stator magnetic field.

[0025]
The housing 13 of the stator 11 has a cylindrical shape having an open end and a closed end. The segments of the permanent magnet 15 are attached to the inner peripheral surface of the housing 13 and are arranged so as to be spaced apart at equal intervals in the circumferential direction, and adjacent segments have different polarities. The open end of the housing 13 faces the transmission 30 and extends outward in the radial direction to form a flange 131. The flange 131 is provided with a through hole 132, and a component such as a screw passes through the through hole 132 of the flange 131 and is fixedly connected to the shell 32 of the transmission 30. The closed end is separated from the transmission 30. The center of the closed end protrudes outward to form a boss 133 for receiving the bearing 20 for supporting the end of the rotor. The boss 133 and the housing 13 are arranged coaxially. In this embodiment, a thrust bearing 21 is provided between the axial end of the bearing 20 and the boss 133. The thrust bearing relieves vibration in the axial direction of the rotor by supporting the rotor shaft so as not to move in the axial direction.

[0026]
The end cap 14 is fixedly connected to the open end of the housing 13. In this embodiment, the end cap 14 includes a cap plate 141 and a cylindrical body 142 that extends axially into the housing 13 from the outer edge of the cap plate 141. The cap plate 141 closes the open end of the shell 32, and the center of the cap plate 141 projects into the transmission 30 to form another boss 143 to accommodate another bearing 22. The other end of the rotor shaft 17 passes through the bearing 22 and the boss 143, extends from the motor 10 and enters the shell 32 of the transmission 30, and the other end of the shaft 17 is connected to the worm 34 by a joint. Is done. The cylindrical body 142 of the end cap 14 is fitted to the housing 13 to fix the end cap 14 to the housing 13. In this embodiment, a plurality of ribs 144 are provided on the outer wall surface of the cylindrical body 142, and the ribs 144 are separated from each other in the circumferential direction of the cylindrical body 142. The brush 16 is disposed on the cylindrical body 142 of the end cap 14. In this embodiment, there are two brushes as shown in FIG.

[0027]
The core 18 of the rotor 12 includes a mounting portion 181 fixed to the rotor shaft 17 and a plurality of teeth 182 extending radially outward from the mounting portion. The winding includes a plurality of coils (not shown) that are wound around the teeth 182. Each tooth 182 includes a winding portion 183 extending from the attachment portion 181 and a pole portion 184 formed at the end of the winding portion 183, and a coil is wound around the winding portion 183. 184 faces the permanent magnet 15 of the stator 11. Adjacent pole portions 184 are separated from each other in the circumferential direction by a gap forming a slot opening 189 of the winding slot 185. The commutator 19 includes an insulating base 191 that is sleeve-fitted to the rotor shaft 17 in a fixed state, and a plurality of commutator bars 193 that are fixed to the base 191. The commutator bars 193 are spaced apart from each other at equal intervals in the circumferential direction of the base 191. The number of commutator bars 193 is the same as the number of teeth 182. One end of each commutator bar 193 facing the core 18 is provided with a hook 194 connected to the corresponding coil. In this embodiment, a plurality of protruding ribs 192 are formed on the outer wall of the base 191, and each of the commutator bars 193 is fixed to the corresponding protruding rib 192. The two brushes 16 are in contact with two of the commutator bars 193 simultaneously, and as the rotor 12 rotates, the two brushes 16 slide on the bars and are electrically connected to different commutator bars 193, respectively. A variable magnetic field is generated by contacting and powering the corresponding coils coupled to the commutator rods 193 alternately away from the commutator rods 193.

[0028]
In the circumferential direction, the width of the slot opening 189 is much smaller than the width of the pole portion 184. The outer surface of each pole portion 184 that faces the permanent magnet 15 is provided with a recess to form at least one groove 186, and the width of the groove 186 is preferably equal to or less than the width of the slot opening 189. A part of the surface of the pole part 184 having the groove 186 is defined as an imaginary part 187, a part of the surface of the pole part 184 without the groove 186 is defined as a real part 188, and the imaginary part 187 is a real part 188. It is preferable to have a width corresponding to the width. Adjacent real parts 188 are separated by two by one imaginary part 187 or one slot opening 189. As the rotor 12 rotates each time by an angle corresponding to one real part 188, the permanent magnet 15 meets one slot opening 189 or one groove 186, and the rotor 12 has rotated a certain angle. After that, the permanent magnet 15 encounters one real part 188 and eventually the alternate arrangement of the slot opening 189, the imaginary part 187, and the real part 188, so that the change in the magnetic resistance of the air gap can be optimized, thereby reducing the cogging torque as much as possible. The vibration and noise of the motor 10 are reduced.

[0029]
In this embodiment, the motor 10 is a motor having four magnetic poles and ten slots, the number of teeth 182 of the rotor core 18 is ten, and the outer surface of the pole portion 184 of each tooth 182 has 2 Two grooves 186 are provided. In the circumferential direction, each pole part 184 is substantially equally divided into five parts, ie, three real parts 188 and two imaginary parts 187, by two grooves 186, and the imaginary part 187 and the real part 188 are Are alternately arranged. The number of grooves 186 in the pole part 184 can be changed according to the dimensions of the slot part of the pole part 184 and the winding slot 185, and is not limited to two.

[0030]
As shown in the following table, noise tests were performed on two motors according to the present invention and two conventional motors. The noise of the conventional # 1 motor during the clockwise (CW) rotation and the counterclockwise (CCW) rotation is 52.0 dBA, and the noise during the clockwise rotation and the counterclockwise rotation is 52.0 dBA. The noise of the # 1 motor with the groove 186 according to the present application was 46.6 dBA and 46.5 dBA, respectively. The noise of the conventional # 2 motor during clockwise rotation and counterclockwise rotation is 51.4 dBA and 49.2 dBB, respectively, during clockwise rotation and counterclockwise rotation. The noise of the # 2 motor according to the present invention provided with grooves was 46.2 dBA and 46.7 dBA, respectively. Therefore, compared with the conventional motor, the noise of the motor according to the present invention can be reduced by about 10%.

[0031]
In the description and claims of this application, the verbs “comprise”, “include”, “contain” and “have”, and variations thereof, refer to elements or features described. It is used in a comprehensive sense to define existence and does not exclude the presence of additional elements or features.

[0032]
It will be understood that certain features of the invention described in connection with separate embodiments for clarity may be provided in combination in one embodiment. Conversely, various features of the invention described in connection with one embodiment for the sake of brevity may be provided individually or in any suitable combination thereof.

[0033]
It will be apparent to those skilled in the art that the above embodiments are merely exemplary, and that various other modifications can be made without departing from the scope of the present invention as defined in the claims.

DESCRIPTION OF SYMBOLS 10 Motor 11 Stator 12 Rotor 13 Housing 14 End cap 15 Permanent magnet 16 Brush 17 Rotor shaft 18 Core 19 Commutator 20 Bearing 21 Thrust bearing 22 Bearing 30 Transmission device 32 Shell 34 Worm 36 Drive gear 38 Output gear 40 Rotating shaft 131 Flange 132 Through hole 133 Boss 141 Cap plate 142 Cylindrical body 143 Boss 144 Rib 181 Mounting part 182 Teeth 183 Winding part 184 Polar part 185 Slot 186 Groove 187 Imaginary part 188 Real part 189 Slot opening part 191 Base 192 Protruding rib 193 Commutating rod 193 hook

Claims (10)

A permanent magnet motor comprising a stator and a rotor disposed in the stator,
The stator includes a housing and a permanent magnet fixed to the inner wall of the housing, and the permanent magnet has four magnetic poles,
The rotor includes a rotor shaft and a rotor core fixed to the rotor shaft,
The rotor core includes an attachment portion that is sleeve-fitted to the rotor shaft, ten teeth that extend outward from the attachment portion, and a plurality of coils that are wound around the teeth. Each includes a winding portion extending from the mounting portion and a pole portion provided at the end of the winding portion, and adjacent pole portions are spaced apart from each other in the circumferential direction to form a slot opening. The outer surface of each pole portion facing the permanent magnet has a groove extending in the axial direction.   The permanent magnet motor according to claim 1, wherein a width of the groove is equal to or less than a width of the slot opening.   The permanent magnet motor according to claim 1, wherein a width of the pole portion is larger than a width of the slot opening portion in a circumferential direction.   A part of the surface of the pole part where the groove is provided is an imaginary part, a part of the surface of the pole part where the groove is not provided is a real part, and the width of the imaginary part is The permanent magnet motor according to claim 3, wherein the permanent magnet motor is approximately the same as the width of the real part.   Two grooves are provided in the pole part, the two grooves divide the pole part into two imaginary parts and three real parts, and the two imaginary parts and the three real parts are: The permanent magnet motor according to claim 4, wherein the permanent magnet motor is alternately arranged.   The rotor further includes a commutator fixed to the rotor shaft, and the commutator includes a base that is sleeve-fitted to the rotor shaft in a fixed state, and a plurality of commutator bars fixed to the base. A hook is provided at one end of each commutator rod facing the rotor core, each hook is connected to a respective coil, and the stator is further in sliding electrical contact with the commutator rod. The permanent magnet motor according to claim 1, further comprising a pair of brushes arranged.   The housing has an open end and a closed end, and an end cap is coupled to the open end, the end cap extending from the cap plate, and a cap plate configured to close the open end The cylindrical body is configured to be inserted into the housing as an interference fit, and a plurality of protruding ribs are formed on an outer wall surface of the cylindrical body. The permanent magnet motor according to any one of 1 to 6.   The permanent magnet motor according to claim 1, wherein the permanent magnet is formed by a plurality of individual permanent magnet segments.   An actuator comprising a motor and a transmission connected to the motor and gearing down the motor, wherein the motor is the permanent magnet motor according to any one of claims 1 to 8, wherein the motor And an end of the rotor shaft of the motor extends to drive the gear train of the transmission.   The transmission includes a shell, a worm and drive gear accommodated in the shell, and an output gear provided outside the shell, and the worm is drivably coupled to the rotor shaft of the motor, Meshed with the drive gear, the drive gear is fixed to a rotation shaft of the actuator, the rotation shaft of the actuator extends from the shell, one end rotatably connected to the shell, The actuator according to claim 9, further comprising: another end fixedly connected to the output gear, wherein the output gear is rotated together with the drive gear.