Patent Application
20230373354
The present application claims priority to Korean Patent Application No. 10-2022-0061228, filed May 19, 2022, the entire contents of which is incorporated herein for all purposes by this reference.
The present disclosure relates to various types of actuators constituting an automotive power seat.
Although DC motors were mainly used for actuators of conventional power seats, considering low noise and long-life characteristics of a BLDC motor, it is highly likely that a BLDC motor will be applied to an actuator of a power seat in the future, and expected that a BLDC motor will be widely applied to various actuators required for a power seat.
There are many advantages when applying a BLDC motor to a power seat, but various parts necessary for sensing a position of a rotor, and switching, controlling and protecting power must be additionally mounted.
On the other hand, according to a trend of high-end automobiles and for the purpose of improving convenience, a plurality of actuators are configured even in a single power seat, and in addition to an original function of a seat, actuators must be accommodated within a limited space, and each function has different rotary/linear drive, reduction ratio, required torque, and mounting posture. Therefore, actuators are designed per each actuator function. In this regard, conventionally, motors have been used for each function of the actuator, but there was a problem in that various production facilities had to be built in order to manufacture different motors for each function.
The present disclosure aims to provide an actuator group for an automotive power seat that can share a motor of various actuators configured in the power seat.
In addition, the present disclosure aims to provide an actuator group for an automotive power seat that can reduce manufacturing cost of various actuators configured in the power seat.
In addition, the present disclosure also aims to provide an actuator group for an automotive power seat that employs a BLDC motor but has a more compact form factor.
Objects of the present disclosure not mentioned above may be more clarified or added through specific details for carrying out the invention.
According to an embodiment of the present disclosure, an actuator group for an automotive power seat includes: three or more types of actuators constituting the power seat of the vehicle, and each actuator of the actuator group includes: a motor assembly 10 having a BLDC motor configured therein; and a reducer assembly 20 coupled to the motor assembly 10 on a side where a motor shaft 15 of the BLDC motor extends and receiving a rotational force of the BLDC motor to decelerate, and the reducer assembly 20 is configured differently from each other depending on a type of an actuator, but the motor assembly 10 is shared.
The actuator comprised in the actuator group for an automotive power seat described hereabove may be any one among a recliner actuator 1 for adjusting an angle of a backrest of the power seat, a relax actuator 4 for adjusting an angle of a backrest of the power seat and a height of a front portion of the power seat, a legrest actuator 2 for adjusting a tilting angle of a legrest of the power seat; a legrest extension actuator 3 for adjusting an extension position of the legrest of the power seat, a tilt actuator 5 for adjusting a height of a front portion of the power seat up and down, a slide actuator for sliding a position of the power seat back and forth, and a height actuator for adjusting an entire height of the power seat up and down.
In the actuator group for an automotive power seat described hereabove, the motor assembly 10 may include: a PCB 11a having a through hole h1 through which the motor shaft 15 passes and a sensor 11b for detecting a position of a rotor of the BLDC motor mounted on one side thereof; and installed in a direction perpendicular to the motor shaft 15, but may expose another side of the PCB 11a, and the reducer assembly 20 may include: a reducer housing 21 accommodating an extension of the motor shaft and reduction gears therein, and the reducer housing 21 may be coupled to the motor assembly 10 while covering another side of the exposed PCB 11a.
In the actuator group for an automotive power seat described hereabove, the motor shaft may be rotatably supported using two shaft bearings, and a second shaft bearing 16 among the two shaft bearings may be located in the reducer housing 21 of the reducer assembly 20.
In the actuator group for an automotive power seat described hereabove, the motor assembly 10 may include: a PCB 11a having a through hole h1 through which the motor shaft 15 passes and a sensor 11b for detecting a position of a rotor 17 of the BLDC motor mounted on one side thereof; and installed in a direction perpendicular to the motor shaft 15, a bearing guide 22 wrapping around an outer circumferential surface of the second shaft bearing 16 and fixed inside the reducer housing 21 is provided to the motor assembly 10, and an outer diameter of the second shaft bearing 16 may be smaller than an inner diameter of the through-hole h1 of the PCB 11a such that the second shaft bearing 16 passes through the through-hole h1 of the PCB 11a during assembly.
In the actuator group for an automotive power seat described hereabove, a material of the bearing guide 22 may be softer than a material of the reducer housing 21 to reduce vibration and noise generated during an operation of the BLDC motor.
In the actuator group for an automotive power seat described hereabove, an end washer 23b contacting one end of the motor shaft 15; and an end rubber 23c elastically supporting the end washer 23b may be located in a cylindrical hole of the reducer housing 21, and in the actuator group for a power seat may include a guide pipe 23a having a through-hole through which the motor shaft 15 passes and coupled to the reducer housing to prevent the end washer 23b from leaving.
In the actuator group for an automotive power seat described hereabove, the reducer assembly 20 may include: a gear set 24 including at least a worm 24a coupled to one side of the motor shaft 15 and a worm wheel 24b tooth-meshed with the worm 24a, and the number of gears, gear ratio, gear pitch and a helix angle of the gear set 24 may be set depending on a type of an actuator.
According to the actuator group for an automotive power seat of the present disclosure, it is possible to reduce manufacturing cost of various actuators configured in the power seat by allowing the motor assembly to be shared.
In addition, according to the actuator group for an automotive power seat of the present disclosure, the reducer housing of the reducer assembly covers the other side of the exposed PCB 11a and is coupled to the motor assembly 10, thereby enabling shared use of the motor assembly and reducing the form factor of the actuator.
In addition, according to the actuator group for an automotive power seat of the present disclosure, by disposing the second shaft bearing 16 serving to support one side of the motor shaft 15 in the reducer housing 21 and making the second shaft bearing 16 be supported by the reducer housing 21, it is possible to configure a more compact actuator.
In addition, according to the actuator group for an automotive power seat of the present disclosure, by providing the bearing guide 22 surrounding the second shaft bearing 16, an outer diameter of the second shaft bearing 16 may be made smaller, and an inner diameter of the through-hole h1 of the PCB 11a may be made smaller, thereby reducing a size (width) of the PCB and a form factor of the actuator.
The actuator included in the actuator group for an automotive power seat according to the embodiment of the present disclosure may be a recliner actuator 1 that adjusts an angle of the backrest of the power seat, a relax actuator 4 that adjusts an angle of a backrest of the power seat and a height of a front portion of the power seat, a legrest actuator 2 that adjusts a tilting angle of a legrest of the power seat, a legrest extension actuator 3 that adjusts a position of a legrest extension of the power seat, a tilt actuator 5 that adjusts a height of the front portion of the power seat up and down, a slide actuator (not illustrated) that slides a position of the power seat back and forth, and a height actuator (not illustrated) that adjusts a height of the entire power seat up and down.
According to the present disclosure, in the recliner actuator 1, the relax actuator 4, the legrest actuator 2, the legrest extension actuator 3, the tilt actuator 5, the slide actuator and the height actuator, the motor assembly 10 used is the same, but the reducer assemblies 20 used are different from each other. The present disclosure provides a recliner reducer assembly (20-1) constituting the recliner actuator 1, a relax reducer assembly (20-4) constituting the relax actuator 4, a legrest reducer assembly (20-2) constituting the legrest actuator 2, a legrest extension reducer assembly (20-1) constituting the legrest extension actuator 3, a tilt reducer assembly (20-5) constituting the tilt actuator 5, a slide reducer assembly constituting the slide actuator, and a height reducer assembly constituting the height actuator.
The reducer assembly 20 is configured differently depending on a type of an actuator, but the motor assembly 10 is shared, and for shared use and to offset an increase in the form factor due to the shared use, a differentiated configuration as described later compared to conventional actuators is used.
Hereinafter, the detailed configuration of the motor assembly 10 and the reducer assembly (20; 20-1) is examined through the recliner actuator 1, centering on the contents that are in common in each actuator in the actuator group.
The motor assembly 10 consists of a BLDC motor, and includes a PCB module 11, a PCB cover 12, a stator housing 13, a stator assembly 14, a motor shaft 15, a rotor 17, a first shaft bearing 18, a second shaft bearing 16 and a bearing cover 19.
The PCB module 11 includes a sensor 11b such as a hall sensor that detects a position of the rotor of the BLDC motor, a terminal 11c where an end of a coil formed in the stator assembly 14 is coupled by soldering, etc., and a PCB 11a having a through-hole h1 through which the motor shaft 15 passes and the sensor 11b mounted on one side thereof; and installed in a direction perpendicular to the motor shaft. In addition to the sensor 11b being installed on one side (inner side) of the PCB 11a, as illustrated, a capacitor 11d and a connector pin 11e for configuring a connector for an electrical connection with an outside are installed therein. The capacitor 11d and the connector are located on an inner surface of the PCB 11a, but are disposed on a side of the stator housing 13 so as to be parallel to the motor shaft. On the other side (outer surface) of the PCB 11a, power devices and controllers are installed for power switching and control.
Since the PCB 11a is installed in a direction perpendicular to the motor shaft 15, direct installation of the sensor 11b that detects a position of the rotor on one side thereof is allowed, and since capacitors, connectors and even semiconductor devices for switching and controlling power and the like are installed in the PCB 11a for the BLDC motor, it is not necessary to install another PCB to mount them in a local or remote location.
The PCB cover 12 includes a short cylinder portion 12c that is similar to a cylindrical shape of the stator housing 13, extends short and has a hollow h2 communicating with the through-hole of the stator housing 13, a side wall portion 12d that is connected to the short cylinder portion 12c and surrounds a side surface of the PCB 11a, and a cylindrical well portion 12b that accommodates the capacitor 11d, and the PCB cover 12 covers one side (inner side) of the PCB 11a while accommodating the PCB module 11 therein, and leaves the other side (outer side) of the PCB 11a open and exposed.
The stator housing 13 has a substantially cylindrical shape with a hollow h3, and accommodates the stator assembly 14 therein, and in an axial direction, one end of the stator housing 13 is coupled to the bearing cover 19 and the other end thereof is coupled to the PCB cover 12. In the stator assembly 14, a coil, a core, and an insulator are arranged circumferentially while surrounding the rotor 17, and the rotor 17 includes a permanent magnet and a core arranged radially while surrounding the motor shaft 15, and the rotor 17 is integrally coupled with the motor shaft 15 penetrating the rotor 17.
The motor shaft 15 is rotatably supported by two shaft bearings. The motor shaft 15 is rotatably supported at one point by the first shaft bearing 18 coupled to the bearing cover 19 and is rotatably supported at the other point by the second shaft bearing 16. The motor shaft 15 is supported at one point by the first shaft bearing 18 and at the other point by the second shaft bearing 16 with respect to the rotor 17. In the present disclosure, the second shaft bearing 16 becomes to be located in the reducer housing 21 of the reducer assembly 20, and the other side of the motor shaft 15 is supported by a supporting force of the reducer housing 21.
In the present disclosure, while the motor assembly 10 is shared, the second shaft bearing 16 supporting the other side of the motor shaft 15 is placed in the reducer housing 21 and supported by the reducer housing 21 (specific details will be described later), thus it is possible to configure a more compact actuator.
The bearing cover 19 is inserted into and coupled to one end of the stator housing 13 by its periphery 19b being inserted into and coupled to one end of the stator housing 13, and is coupled to the first shaft bearing 18 by a fitting piece 19a formed therein being coupled to the first shaft bearing 18.
The reducer assembly 20 is a module that couples the motor assembly 10 on a side where the motor shaft 15 (that is, the motor shaft of the BLDC motor) of the motor assembly 10 extends and receives a rotational force of the BLDC motor to perform deceleration and the like. The reducer assembly 20 includes the reducer housing 21, the bearing guide 22, an end play 23, a mount cap 25, a gear set 24, and a gear cover 26.
The reducer housing 21 accommodates an extension of the motor shaft and gears for reduction therein, and the reducer housing 21 is obtained by an integral injection molding of portions including a PCB cover portion 21a, a gear seating portion 21b, a shaft accommodating portion 21c, and a mount protrusion 21d. The PCB cover portion 21a is fastened to the motor assembly 10 by a bolt or the like, covers the other side of the PCB 11a exposed from the motor assembly 10, and mates with the PCB cover 12. The other side of PCB 11a configured in the motor assembly 10 is designed to be open and exposed to the outside, but the exposed surface is closed by the reducer housing 21 of the reducer assembly 20. Though the reducer assembly is changed depending on a type of the actuator, the PCB module 11 is configured to be accommodated in a closed space formed between the motor assembly and the reducer assembly. In the reducer assembly 20, as the PCB cover portion 21a of the reducer housing 21 is coupled to the motor assembly 20 while covering the other side of the exposed PCB 11a, it becomes possible to reduce a form factor of the actuator while fulfilling shared use of the motor assembly.
The gear seating portion 21b forms an accommodating space r1 that accommodates the gears 24b, 24c, 24e and the gear shaft 24d, except a worm 24a of the gear set 24 therein, and the accommodating space r1 is covered by the gear cover 26. The shaft accommodating portion 21c connects the gear seating portion 21b and the PCB cover portion 21a arranged in a substantially perpendicular direction to each other so that they are integrally coupled to each other, and provides a space for accommodating and supporting one end of the motor shaft 15 to which the worm 24a is coupled and the end play 23. The mount protrusion 21d is used to mount the actuator (reducer assembly), the mount protrusion 21d protrudes outward from the reducer housing 21, and when mounted, the mount cap 25 is used to adjust a clearance with a mounting point.
As described above, the second shaft bearing 16, one of the two shaft bearings, is located and supported in the reducer housing 21 of the reducer assembly 20, and vibration generated during high-speed rotation of the BLDC motor is transmitted to the reducer housing 21 and may cause noise. In order to prevent or reduce such vibration and noise, according to the embodiment of the present disclosure, the bearing guide 22 mounted inside the reducer housing 21 is configured.
The bearing guide 22 may be first assembled to the second shaft bearing 16 or to one of the reducer housings 21 by a method such as press-fitting, thermal fusion, caulking, or impression, and then assembled with the other side.
As illustrated in
After the bearing guide 22 is mounted inside the reducer housing 21, when assembling the motor assembly 10 and the reducer assembly 20, the second shaft bearing 16 fixed to the motor shaft 15 of the motor assembly 10 is seated in a hollow part h4 of the bearing guide 22, so the bearing guide 22 wraps around and supports an outer circumference of the second shaft bearing 16. The reducer housing 21 has a complex shape and is made of a material with high rigidity for supporting the gear set 24 and the motor shaft 16, whereas, the bearing guide 22 is made of a softer material than the material of the reducer housing 21 so that vibration and noise generated during operation of the BLDC motor can be reduced.
In addition, by forming an outer diameter of the second shaft bearing 16 to be smaller than an inner diameter of the through-hole h1 of the PCB 11a, the second shaft bearing 16 may pass through the through-hole h1 of the PCB 11a during the assembly.
According to the present disclosure, by providing the bearing guide 22 surrounding the second shaft bearing 16, an outer diameter of the second shaft bearing 16 may be made smaller and an inner diameter of the through-hole h1 of the PCB 11a may be made smaller, and accordingly, the size (width) of the PCB and the form factor of the actuator may be reduced.
Assume that as an outer diameter of the second shaft bearing increases, if an inner diameter of the through-hole h1 of the PCB 11a has to be made greater, a mounting area of the parts that may be mounted on the PCB 11a is consumed more. When looking at the present disclosure differently, by reducing the consumption of such a mounting area, a wider mounting area may be secured, and various elements necessary for driving the BLDC motor may be mounted together with the sensor 11b, thereby eliminating a need to install another PCB locally or remotely to mount them.
According to the embodiment of the present disclosure, the end play 23, which is configured to stabilize an axial position of the motor shaft 15 at the other end of the motor shaft 15 and to absorb a thermal expansion of the motor shaft 15, is characterized in that it is configured in the reducer housing 21, specifically, the shaft accommodating portion 21c of the reducer housing 21 (see
In the end play 23, an end washer 23b contacting one end of the motor shaft 15 and an end rubber 23c elastically supporting the end washer 23b becomes to be located in a multi-stage cylindrical hole in the reducer housing 21 (specifically, the shaft accommodating portion 21c), and a guide pipe 23a having a through-hole through which the motor shaft 15 passes and coupled to the reducer housing 21 to prevent the end washer 23b from leaving are equipped therewith.
According to the embodiment of the present disclosure, in the reducer assembly, the configuration of the gear set 24 and the like may be different per actuator, but inner shapes of the PCB cover portion 21a and the shaft accommodating portion 21c together with the bearing guide 22 and the end play 23 in the reducer housing 21 are preferably the same.
In addition, the reducer assembly 20 includes gear set 24 including the worm 24a coupled to one side of the motor shaft 15, a worm wheel 24b tooth-meshed with the worm 24a, a first helical wheel 24c shaft-coupled to the worm wheel 24b, and a second helical wheel 24c tooth-meshed with the first helical wheel 24c. The driving force of the BLDC motor is transmitted in the order of the motor shaft-worm-worm wheel-first helical wheel-second helical wheel 24e.
Depending on a type of an actuator, the first helical wheel 24c and the second helical wheel 24e may not be configured. For example, like the recliner actuator 1, the relax actuator 4, the legrest actuator 2, the legrest extension actuator 3, and the tilt actuator 5 include a worm coupled to the other side of the motor shaft and a worm wheel tooth-meshing with the worm. By the way, both sides of the worm wheel in an axial direction have washers interposed therebetween, and the worm wheel is supported by the reducer housing so that the worm wheel can be rotatable in place, and a thread is formed on an inner circumferential surface of a hollow formed at a center to tooth-mesh with a lead screw penetrating the washers, so that the worm wheel drives the lead screw. The driving force of the BLDC motor is transmitted in the order of the motor shaft-worm-worm wheel-lead screw.
Even if the types of actuators are different, the reducer assembly of each actuator includes at least a worm 24a and a worm wheel 24b tooth-meshing with the worm 24a. Also, depending on a type of an actuator, the number of gears in the gear set 24 may be different, and the gear ratio, gear pitch, and helix angle may be set differently.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2022-0061228 | May 2022 | KR | national |
