A motor drive structure for a seat belt and a seat belt retractor having the same

Abstract

The present invention discloses a motor-driven structure for a safety belt and a safety belt retractor having the same. The motor-driven structure comprises a motor, a reduction mechanism assembly, a main gear, a clutch assembly and a core shaft assembly. The output end of the motor is connected to the reduction mechanism assembly, the output end of the reduction mechanism assembly is meshed with the main gear, the main gear is connected to the core shaft assembly through the clutch assembly, and the core shaft assembly is driven to rotate by the motor; a driving gear is provided at the output end of the motor, the reduction mechanism assembly comprises a planetary carrier gear assembly and a stepped gear, the stepped gear comprises a driving external gear and a primary driven gear, and the driving external gear and the primary driven gear are coaxially integrated; the driving gear is meshed with the primary driven gear, and the driving external gear is connected to the planetary carrier gear assembly; the main gear is rotated by the primary driven gear, the driving external gear and the planetary carrier gear assembly, the main gear is connected to the core shaft assembly through the clutch assembly, and the core shaft assembly is driven to rotate by the motor.

Description

Technical Field

[0001] The present invention relates to the technical field of seat belts, and in particular to a motor drive structure for a seat belt and a seat belt retractor having the same. Background Art

[0002] Seat belts are essential safety devices in cars. They can firmly fasten occupants to their seats in the event of a vehicle collision or emergency braking. They protect the safety of people in the event of a vehicle accident and are an important part of the passive safety system. In the existing technology, pyrotechnic pretensioners are usually used for ignition and detonation. Since pyrotechnic pretensioners use an explosive gas generator to drive the webbing to rewind, they cannot be reused. Once detonated, they must be replaced as a whole, resulting in high costs. They are disposable and irreversible, which leads to limitations in their use. Summary of the Invention

[0003] To this end, the present invention provides a seat belt motor drive structure and a seat belt retractor having the same, so as to solve the problems in the prior art of non-reusability, irreversibility and high cost of pyrotechnic pretensioners.

[0004] In order to achieve the above object, the present invention provides the following technical solutions:

[0005] According to the present invention, a motor drive structure for a seat belt is provided, comprising a motor, a reduction mechanism assembly, a main gear, a clutch assembly, and a spindle assembly, wherein the output end of the motor is connected to the reduction mechanism assembly, the output end of the reduction mechanism assembly is meshed with the main gear, the main gear is connected to the spindle assembly via the clutch assembly, and the spindle assembly is driven to rotate by the motor;

[0006] The output end of the motor is provided with a driving gear, the reduction mechanism assembly includes a planetary carrier gear assembly and a stepped gear, the stepped gear includes a driving external gear and a first-stage driven gear, the driving external gear and the first-stage driven gear are coaxially arranged as a whole; the driving gear is meshed with the first-stage driven gear, and the driving external gear is connected to the planetary carrier gear assembly;

[0007] When the driving gear rotates, the main gear rotates through the primary driven gear, the driving external gear and the planetary carrier gear assembly. The main gear is connected to the core shaft assembly through the clutch assembly, and the core shaft assembly is driven to rotate by the motor.

[0008] Furthermore, the planetary carrier gear assembly further includes a common planetary gear, and the common planetary gear is meshedly connected with the driving external gear.

[0009] Furthermore, the number of the common planetary gears is one or more. When the number of the common planetary gears is more than one, they are evenly distributed along the circumferential direction of the driving external gear.

[0010] Furthermore, the number of the common planetary gears is 3-5.

[0011] Furthermore, the planetary carrier gear assembly also includes a planetary gear internal gear, and the planetary gear internal gear is fixed on the base of the speed reduction mechanism assembly.

[0012] Furthermore, the planetary carrier gear assembly further includes a planetary carrier gear, and the planetary carrier gear is arranged on a side of the planetary gear inner gear axially away from the base.

[0013] Furthermore, a cylinder is provided on the surface of the planetary carrier gear facing the common planetary gear, and the cylinder is arranged opposite to the axis of the common planetary gear.

[0014] Furthermore, the number of the cylinders is the same as the number of the common planetary gears.

[0015] Furthermore, the motor is a brushed DC motor.

[0016] The present invention also provides a seat belt retractor, which comprises the seat belt motor drive structure described above.

[0017] The present invention has the following advantages:

[0018] The present invention adopts an electric motor, and uses a driving gear at the output end of the electric motor to rotate the main gear through a primary driven gear, a driving external gear and a planetary carrier gear assembly. The main gear is connected to the core shaft assembly through the clutch assembly, so that the core shaft assembly is driven to rotate by the electric motor. When pre-tightening the seat belt, the electric motor can be reused, and the forward and reverse rotation of the core shaft assembly can be achieved by the forward and reverse rotation of the electric motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other implementation drawings based on the provided drawings without inventive effort.

[0020] The structures, proportions, sizes, etc. illustrated in this specification are intended only to complement the contents disclosed herein and to facilitate understanding and reading by persons familiar with the art. They are not intended to limit the conditions under which the present invention may be implemented and therefore have no substantive technical significance. Any structural modifications, changes in proportions, or adjustments in sizes, without affecting the efficacy and objectives of the present invention, shall still fall within the scope of the technical contents disclosed herein.

[0021] Figure 1 FIG1 is a schematic diagram of the overall structure of a motor-driven seat belt retractor according to an exemplary embodiment;

[0022] Figure 2 FIG1 is a schematic diagram of a transmission structure of a motor drive structure for a seat belt according to an exemplary embodiment;

[0023] Figure 3 FIG1 is a transmission structure diagram of a motor drive structure for a seat belt according to an exemplary embodiment (excluding the planetary carrier gear);

[0024] Figure 4 FIG1 is a schematic diagram of a transmission structure of a motor drive structure for a seat belt according to an exemplary embodiment (with a base);

[0025] Figure 5 1 is a schematic structural diagram of a stepped gear according to an exemplary embodiment;

[0026] Figure 6 is a schematic structural diagram of a planetary carrier gear according to an exemplary embodiment;

[0027] Figure 7 FIG1 is a schematic diagram of a transmission structure of a high-torque motor drive structure for a seat belt according to an exemplary embodiment;

[0028] Figure 8 FIG1 is a schematic structural diagram of a high-torque motor drive structure for a seat belt according to an exemplary embodiment;

[0029] Figure 9 FIG1 is a structural schematic diagram of a high-torque motor drive structure for a seat belt from another perspective according to an exemplary embodiment;

[0030] Figure 10 1 is a schematic structural diagram of a high-torque motor drive structure for a seat belt according to an exemplary embodiment (excluding the secondary transmission gear);

[0031] Figure 11 is a schematic structural diagram of an eccentric structural assembly according to an exemplary embodiment;

[0032] Figure 12 FIG1 is a schematic diagram of an exploded structure of a seat belt retractor according to an exemplary embodiment;

[0033] Figure 13 FIG1 is a structural schematic diagram of a seat belt retractor according to an exemplary embodiment (with the outer cover removed);

[0034] Figure 14 1 is a schematic structural diagram of a coil spring cover according to an exemplary embodiment;

[0035] Figure 15 is a structural schematic diagram showing a safety belt trigger structure in a triggered state according to an exemplary embodiment;

[0036] Figure 16 FIG1 is a schematic structural diagram of a safety belt trigger structure in a non-triggering state according to an exemplary embodiment;

[0037] Figure 17 1 is a schematic structural diagram of a shear assembly for a safety belt according to an exemplary embodiment;

[0038] Figure 18 Schematic diagram of the structure of a pin hole according to an exemplary embodiment. DETAILED DESCRIPTION

[0039] The following describes the implementation of the present invention using specific embodiments. Those skilled in the art will readily understand the other advantages and benefits of the present invention from the disclosure herein. Obviously, the embodiments described are only a portion of the present invention, not all of it. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to fall within the scope of protection of the present invention.

[0040] According to an embodiment of the present invention, a motor-driven safety retractor is provided. Figures 1 to 18 As shown, it includes a motor 600, a reduction mechanism assembly 200, a main gear 900, a clutch assembly 300 and a spindle assembly 500, wherein the output end of the motor 600 is connected to the reduction mechanism assembly 200, the output end of the reduction mechanism assembly 200 is meshed with the main gear 900, the main gear 900 is connected to the spindle assembly 500 through the clutch assembly 300, and the spindle assembly 500 is driven to rotate by the motor 600;

[0041] Among them, the output end of the motor 600 is provided with a driving gear 601, and the reduction mechanism assembly 200 adopts a planetary gear structure or an eccentric swing gear structure. The motor 600 is decelerated by the reduction mechanism assembly 200 and the motion is transmitted to the main gear 900. The main gear 900 is connected to the core shaft assembly 500 through the clutch assembly 300, so that the core shaft assembly 500 is driven to rotate by the motor 600.

[0042] The motor-driven safety retractor provided by the present invention has a motor 600 that is decelerated by the deceleration mechanism assembly 200 and transmits the motion to the main gear 900. The main gear 900 is connected to the core shaft assembly 500 through the clutch assembly 300, so that the core shaft assembly 500 is driven to rotate by the motor 600. The motor 600 can be reused when pre-tightening the seat belt, and the forward and reverse rotation of the core shaft assembly 500 can be achieved by the forward and reverse rotation of the motor 600.

[0043] In some optional embodiments, the motor-driven safety retractor further includes a coil spring assembly 100, which is disposed on a side of the spindle assembly 500 proximate to the clutch assembly 300. The coil spring assembly 100 includes a coil spring cover 12 and a coil spring 101, which is disposed within the coil spring cover 12 and connected to the axial end of the spindle assembly 500. The coil spring 101 enables the safety belt wrapped around the spindle assembly 500 to be retracted, ensuring that the safety belt remains in contact with the wearer's body.

[0044] In some optional embodiments, the motor-driven safety retractor further includes a control unit 400, which is disposed inside the motor-driven safety retractor and is used to control the motor 600 and the clutch assembly 300, such as controlling the motor 600 to stop rotating.

[0045] In some optional embodiments, the motor-driven safety retractor further includes a pretensioner assembly 700, which is disposed on the outside of the core shaft assembly 500. When an emergency occurs in the vehicle, the core shaft assembly 500 is pretensioned, and the pretensioning can be achieved by using a motor 600.

[0046] The driving structure in the embodiment of the present invention can adopt a motor drive structure for a seat belt, including a motor 600, a reduction mechanism assembly 200, a main gear 900, a clutch assembly 300 and a spindle assembly 500, wherein the output end of the motor 600 is connected to the reduction mechanism assembly 200, the output end of the reduction mechanism assembly 200 is meshed with the main gear 900, the main gear 900 is connected to the spindle assembly 500 through the clutch assembly 300, and the spindle assembly 500 is driven to rotate by the motor 600; wherein the output end of the motor 600 is provided with a driving gear 601, the reduction mechanism assembly 200 includes a planetary carrier gear assembly 201 and a step gear assembly 500. Gear 202, the stepped gear 202 includes a driving external gear 2021 and a first-level driven gear 2022, the driving external gear 2021 and the first-level driven gear 2022 are coaxially arranged as a whole; the driving gear 601 is meshed and connected with the first-level driven gear 2022, and the driving external gear 2021 is connected to the planetary carrier gear assembly 201; when the driving gear 601 rotates, the first-level driven gear 2022, the driving external gear 2021 and the planetary carrier gear assembly 201 cause the main gear 900 to rotate, and the main gear 900 is connected to the core shaft assembly 500 through the clutch assembly 300, so that the core shaft assembly 500 is driven to rotate by the motor 600.

[0047] The present invention adopts an electric motor 600, through the driving gear 601 at the output end of the electric motor 600, through the first-level driven gear 2022, the driving external gear 2021 and the planetary carrier gear assembly 201, so that the main gear 900 rotates. The main gear 900 is connected to the core shaft assembly 500 through the clutch assembly 300, so that the core shaft assembly 500 is driven to rotate by the electric motor 600. When pre-tightening the seat belt, it can be reused, and the forward and reverse rotation of the core shaft assembly 500 can be achieved by the forward and reverse rotation of the electric motor 600.

[0048] In some optional embodiments, the planetary carrier gear assembly 201 further includes a common planetary gear 2011, which is meshed with the driving external gear 2021. The common planetary gear 2011 is disposed circumferentially outside the driving external gear 2021, and rotation of the driving external gear 2021 drives the common planetary gear 2011 to rotate. There can be one or more common planetary gears 2011. When there are multiple common planetary gears 2011, for example, there can be 3-5 common planetary gears 2011, which are evenly distributed along the circumference of the driving external gear 2021. The planetary carrier gear assembly 201 further includes a planetary internal gear 2012, which is fixed to the base 2013 of the reduction mechanism assembly 200 and connected via a spline 2015. When the common planetary gear 2011 rotates, the planetary internal gear 2012 remains stationary. The planetary carrier gear assembly 201 further includes a planetary carrier gear 2014, which is disposed on a side of the planetary gear inner gear 2012 axially away from the base 2013 and can be meshed with the main gear 900. A cylindrical body 2016 is provided on the surface of the planetary carrier gear 2014 facing the common planetary gear 2011. The cylindrical body 2016 is disposed opposite the axis of the common planetary gear 2011 and is inserted into the axis of the common planetary gear 2011. When the common planetary gear 2011 rotates, the cylindrical body 2016 rotates synchronously with the common planetary gear 2011, and the rotation of the cylindrical body 2016 drives the planetary carrier gear 2014 to rotate. The number of the cylindrical bodies 2016 is the same as the number of the common planetary gears 2011, which can be three to five. The specific positions of the cylindrical bodies 2016 correspond to the center of the common planetary gear 2011. The motor 600 is a brushed DC motor with a voltage of 12V / 24V / 36V / 48V and a maximum current of 40A. It has the characteristics of fast starting, timely braking, smooth speed regulation over a wide range, and a relatively simple control circuit.

[0049] The drive structure in the embodiment of the present invention can also be a high-torque motor drive structure for a seat belt, including a motor 600, a reduction mechanism assembly 200, a main gear 900, a clutch assembly 300 and a spindle assembly 500, wherein the output end of the motor 600 is connected to the reduction mechanism assembly 200, the output end of the reduction mechanism assembly 200 is meshed with the main gear 900, the main gear 900 is connected to the spindle assembly 500 through the clutch assembly 300, and the spindle assembly 500 is driven to rotate by the motor 600; wherein, The output end of the motor 600 is provided with a driving gear 601. The speed reduction mechanism assembly 200 includes an oscillating gear assembly 203, an eccentric structure assembly 204, and a secondary transmission gear 205. The eccentric structure assembly 204 includes an eccentric shaft 2041 and a primary transmission gear 2042. The eccentric shaft 2041 and the primary transmission gear 2042 are integrally provided. The driving gear 601 is meshed and connected with the primary transmission gear 2042. The eccentric shaft 2041 is connected to the oscillating gear assembly 203. The oscillating gear assembly 203 is connected to the secondary transmission gear 205.

[0050] When the driving gear 601 rotates, the main gear 900 rotates through the primary transmission gear 2042, the swing gear assembly 203 and the secondary transmission gear 205. The main gear 900 is connected to the core shaft assembly 500 through the clutch assembly 300, so that the core shaft assembly 500 is driven to rotate by the motor 600.

[0051] In the present invention, when the driving gear 601 rotates, the main gear 900 is rotated through the primary transmission gear 2042, the swing gear assembly 203 and the secondary transmission gear 205. The main gear 900 is connected to the core shaft assembly 500 through the clutch assembly 300, so that the core shaft assembly 500 is driven to rotate by the motor 600. When the seat belt is pre-tightened, it can be reused, and the forward and reverse rotation of the core shaft assembly 500 can be achieved by the forward and reverse rotation of the motor 600. It has the characteristics of simple structure and high transmission torque.

[0052] In some optional embodiments, the eccentric oscillating gear structure includes an oscillating gear assembly 203, an eccentric structural assembly 204, and a secondary transmission gear 205. The eccentric structural assembly 204 includes an eccentric shaft 2041 and a primary transmission gear 2042, and the eccentric shaft 2041 and the primary transmission gear 2042 are integrally formed. The driving gear 601 is meshed with the primary transmission gear 2042, and the eccentric shaft 2041 is connected to the oscillating gear assembly 203, which is connected to the secondary transmission gear 205. The end surface of the secondary transmission gear 205 is provided with a plurality of through holes 2051, which are evenly distributed around the axis of the secondary transmission gear 205. The oscillating gear assembly 203 includes an oscillating gear 2031 and a transmission member 2032, which is disposed on the surface of the oscillating gear 2031 facing the secondary transmission gear 205, and is disposed opposite the through holes 2051. By providing the transmission member 2032 and the through-hole 2051, the rotation of the swing gear 2031 can be transmitted to the rotation of the secondary transmission gear 205, thereby achieving motion transmission. The transmission member 2032 is cylindrical, and its diameter is smaller than the diameter of the through-hole 2051. The cylindrical shape of the transmission member 2032 ensures a smooth transmission process and increases contact between the transmission member 2032 and the through-hole 2051 compared to a truncated cone or prism shape. There are six through-holes 2051, and the number of through-holes 2051 is the same as the number of transmission members 2032. Of course, the number of transmission members 2032 can also be less than the number of through-holes 2051, and rotation transmission can still be achieved. During the transmission process, the transmission member 2032 is inserted into the through-hole 2051. As the swing gear 2031 rotates, it drives the transmission member 2032 to rotate synchronously, thereby driving the rotation of the secondary transmission gear 205. The high-torque motor drive structure for the seat belt also includes a reduction internal gear 206, which is arranged on the circumferential outer side of the swing gear 2031 and is meshed with the swing gear 2031. The reduction internal gear 206 is fixed to the base of the reduction mechanism assembly 200 using a spline structure. By providing the reduction internal gear 206 and cooperating with the swing gear 2031, the reduction of the reduction mechanism assembly 200 is achieved. The number of teeth of the reduction internal gear 206 is greater than the number of teeth of the swing gear 2031. The number of teeth of the reduction internal gear 206 is 36, and the number of teeth of the swing gear 2031 is 32 to 35. By providing a difference in the number of teeth between the reduction internal gear 206 and the swing gear 2031, the reduction of the reduction mechanism assembly is achieved.The swing amplitude of the swing gear assembly 203 is not greater than the eccentricity of the eccentric structure assembly 204. The specific relationship between the eccentricity and the swing amplitude is not limited here. The present invention adopts an eccentric structure assembly to realize the transmission of motion, and can achieve multi-stage deceleration during the transmission process.

[0053] According to an embodiment of the present invention, a trigger structure for a seat belt is also provided, including a magnet 15 and a Hall sensor 14. The magnet 15 is arranged on the side of the coil spring cover 12 facing the coil spring, and the Hall sensor 14 is arranged on the base 2013. The base 2013 is provided with a first groove 20131. Under the action of the coil spring 101, the magnet 15 moves along the first groove 20131. When the magnet 15 is opposite to the Hall sensor 14, the magnet 15 triggers the Hall sensor 14.

[0054] The trigger structure of the embodiment of the present invention is that when the magnet 15 moves along the first groove 20131, when it reaches the limit position of the coil spring 101, the magnet 15 is opposite to the Hall sensor 14, thereby triggering the Hall sensor, causing the motor to stop, preventing the coil spring 101 from being damaged, and avoiding the phenomenon of exceeding the limit position of the coil spring 101 and damaging the coil spring 101.

[0055] In some optional embodiments, the coil spring cover 12 is further provided with a spring mounting portion 121, and the spring mounting portion 121 extends tangentially along the circumference of the coil spring cover 12. There is one spring mounting portion 121, and one end of the spring 102 is fixed to the spring mounting portion 121, wherein a portion of the spring 102 is sleeved on the outer surface of the spring mounting portion 121. The spring mounting portion 121 is cylindrical or truncated cone-shaped. When the spring mounting portion 121 is truncated cone-shaped, the end close to the coil spring cover 12 is the large end. The cylindrical or truncated cone-shaped spring mounting portion 121 can prevent the spring 102 from being obstructed by the side of the spring mounting portion 121 during the compression process, so that the entire compression and expansion process of the spring 102 is smooth. The end surface of the base 2013 opposite to the coil spring cover 12 is provided with a second groove 20132. When the coil spring cover 12 rotates, the spring mounting portion 121 can move in the second groove 20132 to compress or release the spring 102. The space between the second groove 20132 and the spring mounting portion 121 is the movable space of the spring 102. The seat belt trigger structure also includes a positioning cover 13, which is arranged between the coil spring cover 12 and the base 2013. The positioning cover 13 is mainly provided to facilitate the installation of the coil spring cover 12 and the coil spring 101. The control unit 400 is connected to the Hall sensor 14 and is used to turn off the motor 600 according to the signal sent by the Hall sensor 14. The control unit 400 is used to control the start and stop of the motor 600 and the size of the rotation speed. The trigger structure for the seat belt also includes a magnet mounting portion 122, one end of which is fixed to the edge of the coil spring cover 12 and extends along the central axis of the coil spring cover 12 in the direction close to the Hall sensor 14. By providing the magnet mounting portion 122, the distance between the magnet 15 and the Hall sensor 14 can be made closer, making the trigger structure more sensitive. The magnet mounting portion 122 is cylindrical, truncated cone or rectangular. In actual use, the magnet mounting portion 122 can also adopt other shapes as long as the distance between the magnet 15 and the Hall sensor 14 can be made closer. The magnet 15 is embedded in the end of the magnet mounting portion 122. By adopting this installation method, the magnet 15 can be prevented from falling off, and the failure of the trigger structure due to the falling off of the magnet 15 can be avoided.When the spring 102 is in its ultimate compression state, the magnet 15 faces the Hall sensor 14, triggering the Hall sensor 14. The control unit 400, based on the signal from the Hall sensor 14, stops the motor 600 to prevent the coil spring 101 from exceeding its ultimate position. The coil spring cover 12 then rotates in the opposite direction under the action of the spring 102, causing the coil spring 101 to expand to a certain extent, displacing the magnet 15 from facing the Hall sensor 14, effectively placing the magnet 15 in a non-triggering position. The first and second grooves 20131, 20132 are respectively disposed on either side of the annular ring in the base 2013, and are both arc-shaped.

[0056] According to an embodiment of the present invention, a shearing assembly for a seat belt is further provided, comprising a pin 501 and a pin hole 104, wherein the pin 501 is arranged at one end of the core shaft assembly 500 close to the shaft head of the coil spring assembly 100, and the pin hole 104 is arranged on the shaft head of the coil spring assembly 100; or, the pin 501 is arranged at one end of the shaft head of the coil spring assembly 100, and the pin hole 104 is arranged at one end of the core shaft assembly 500 close to the shaft head of the coil spring assembly 100; the pin hole 104 is opposite to the pin 501; when the shaft head of the coil spring assembly 100 is connected to the core shaft assembly 500, the pin 501 is inserted into the pin hole 104.

[0057] The present invention provides a pin 501 and a pin hole 104. When the motor structure is used to drive the seat belt retractor and both ends of the core shaft assembly 500 are fixed and locked at the same time, the core shaft assembly 500 can be sheared when the locking force reaches a certain value, thereby allowing the core shaft assembly to continue to perform force limiting control to relieve the pressure of the seat belt on the occupant's chest.

[0058] In some optional embodiments, the number of the pins 501 is one or more, and they are arranged on the end face of the spindle assembly 500; the number of the pin holes 104 is the same as the number of the pins 501, and the positions of the pin holes 104 are opposite to the corresponding pins 501. The number of pins 501 is related to the force required for shearing. When the force required for shearing is small, the number of pins 501 can be selected to be smaller. For example, when the spindle assembly 500 is set to be locked to 75 Newtons, one pin 501 can be selected. When the spindle assembly 500 is set to be locked to 150 Newtons, the pin 501 is sheared, and two pins 501 can be selected, wherein the two pins 501 and the center of the end face of the spindle assembly 500 are on the same straight line. A protrusion 103 is formed on the axial inner surface of the coil spring assembly 100, and a pin hole 104 is provided on the protrusion 103 of the coil spring assembly 100. The protrusion 103 has an arc-shaped cross section, and the pin hole 104 is provided along the axial direction of the protrusion 103. The pin 501 is cylindrical, the pin hole 104 is circular, and the diameter of the pin hole 104 matches the diameter of the pin 501. Alternatively, the pin 501 is truncated cone-shaped, with its large end contacting the core shaft assembly 500, and the shape and size of the pin hole 104 match the shape and size of the pin 501. Alternatively, the pin 501 is rectangular, the pin hole 104 has a rectangular cross section, and the size of the pin hole 104 matches the size of the pin 501. Alternatively, the pin 501 is pyramid-shaped, and the size of the pin hole 104 matches the shape and size of the pin. When making a selection, the pin 501 can also be of other shapes, as long as it is adapted to the shape of the pin hole 104, wherein the size of the pin hole 104 is slightly larger than the size of the pin 501, so that the pin 501 can normally enter the pin hole 104. When the number of the pin 501 is one, its center position is set at a non-center position of the end face of the core shaft assembly 500. When the number of the pins 501 is multiple, the multiple pins 501 are evenly distributed on the end face of the core shaft assembly 500 along the center of the end face of the core shaft assembly 500, wherein the number of the pins 501 is two, and other numbers of pins can be selected as needed for setting, such as 3 or 4, wherein the distance between the center position of the pin 501 and the center position of the end face of the core shaft assembly 500 is not specifically limited. The material of the pin 501 is metal or plastic. The pin 501 can be made of the same material as the core shaft assembly 500 and formed in an integral manner, or it can be made of a different material and secured to the end face of the core shaft assembly 500 by welding or bonding. The seatbelt retractor further includes an outer cover 11 for enclosing the speed reduction mechanism assembly 200 and the coil spring cover 12.

[0059] In some optional embodiments, the motor-driven safety retractor further includes a mechanical end assembly 800, which is disposed on a side of the spindle assembly 500 proximate to the pretensioner assembly 700. The mechanical end assembly 800 includes a sensor assembly and a locking mechanism, wherein the sensor assembly includes a vehicle sensor, a belt sensor, and a tilt angle sensor. The sensor assembly can sense an emergency situation within the vehicle and promptly trigger a gas generator. The locking mechanism can quickly lock the seatbelt retractor, thereby buffering the pressure on the seatbelt.

[0060] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made thereto. Therefore, such modifications and improvements, without departing from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A motor drive structure for a seat belt, characterized in that: It includes a motor, a reduction mechanism assembly, a main gear, a clutch assembly and a spindle assembly, wherein the output end of the motor is connected to the reduction mechanism assembly, the output end of the reduction mechanism assembly is meshed with the main gear, the main gear is connected to the spindle assembly through the clutch assembly, and the spindle assembly is driven to rotate by the motor; The motor is a brushed DC motor, and a driving gear is provided at the output end of the motor. The reduction mechanism assembly includes a planetary carrier gear assembly and a stepped gear. The stepped gear includes a driving external gear and a first-stage driven gear. The driving external gear and the first-stage driven gear are coaxially arranged as a whole. The driving gear is meshed with the first-stage driven gear, and the driving external gear is connected to the planetary carrier gear assembly. When the driving gear rotates, the main gear rotates through the primary driven gear, the driving external gear and the planetary carrier gear assembly. The main gear is connected to the core shaft assembly through the clutch assembly, and the core shaft assembly is driven to rotate by the motor. The planetary carrier gear assembly also includes a common planetary gear, which is meshed with the driving external gear; the planetary carrier gear assembly also includes a planetary gear internal gear, which is fixed to the base of the reduction mechanism assembly; the planetary carrier gear assembly also includes a planetary carrier gear, which is arranged on the axial side of the planetary gear internal gear away from the base; a cylinder is provided on the surface of the planetary carrier gear facing the common planetary gear, and the cylinder is arranged opposite to the axis of the common planetary gear; wherein the number of the cylinders is the same as the number of the common planetary gears.

2. A motor drive structure for a seat belt according to claim 1, characterized in that: The number of the common planetary gears is one or more. When the number of the common planetary gears is more than one, they are evenly distributed along the circumferential direction of the driving external gear.

3. A motor drive structure for a seat belt according to claim 2, characterized in that: The number of the common planetary gears is 3-5.

4. A seat belt retractor, characterized in that: The seatbelt retractor includes the seatbelt motor drive structure according to any one of claims 1 to 3.

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