JP5388359B2 - Seat belt retractor and seat belt device provided with the same - Google Patents

Description

  The present invention relates to a technical field of a seat belt retractor configured as a motor retractor that performs belt winding and belt withdrawal by driving and controlling the rotation of a spool with a driving unit such as an electric motor, and a seat belt device including the same. In particular, the present invention relates to a technical field of a seat belt retractor including a rotation amount detection member for detecting a rotation amount of a spool and a seat belt apparatus including the same.

  2. Description of the Related Art Conventionally, a seat belt device that has been installed in a vehicle such as an automobile prevents an occupant from jumping out of a seat by restraining the occupant with the seat belt in an emergency such as a vehicle collision. Such a seat belt apparatus includes a seat belt retractor that winds up the seat belt. In this seat belt retractor, the seat belt is wound around the spool when not worn, but is pulled out and worn by the occupant when worn. Then, the seat belt retractor is actuated in the event of an emergency as described above to prevent rotation of the spool in the belt withdrawing direction, thereby preventing the seat belt from being withdrawn. As a result, the occupant is restrained by the seat belt in an emergency.

  In the conventional seat belt device, various belt tension modes are set according to the traveling state of the vehicle and the usage state of the seat belt device, and a spool for winding the seat belt as a seat belt retractor is driven by the motor power. There are many known seat belt devices including a motor retractor that rotates. In this seat belt retractor, the controller drives and controls the electric motor as a driving means so that the belt tension in the belt tension mode (belt tension) set in accordance with the traveling state of the vehicle and the usage state of the seat belt device. This controls the spool winding and withdrawal of the spool.

  Incidentally, in order for the controller to control the winding of the spool and the withdrawal of the belt by controlling the drive of the electric motor, it is necessary to detect the amount and direction of rotation of the spool. Therefore, as a rotation sensor for detecting the amount and direction of rotation of the spool, a rotating disk supported on the rotating shaft of the spool so as to rotate integrally with the spool, a magnet, and the rotation of the rotating disk by detecting the magnet are detected. A seat belt retractor that includes a rotation sensor that includes a Hall element (Hall IC) to be detected and that controls an electric motor based on the amount of rotation of the spool detected by the rotation sensor has been proposed (for example, Patent Document 1).

FIG. 6 is a view showing the seat belt device described in Patent Document 1, FIG. 7 is a view showing a part of the seat belt retractor described in Patent Document 1, and FIG. 8A is described in Patent Document 1. FIG. 8B is a partial view corresponding to the VIIIB portion in FIG. 8A, FIG. 8C is a cross-sectional view taken along the line VIIIC-VIIIC in FIG. FIG. 6 is a diagram for explaining rotation detection by a rotation sensor. In FIGS. 6 to 9, 1 is a seat belt device, 2 is a vehicle seat, 3 is a seat belt retractor configured as a motor retractor, and 4 is a seat belt retractor. The seat belt 4 is wound so that it can be pulled out and the belt anchor 4a at the front end is fixed to the floor of the vehicle body or the vehicle seat 2. Reference numeral 5 denotes a seat belt 4 pulled out from the seat belt retractor 3. Guide anchor that guides the shoulder, 6 is a tongue that is slidably supported by the seat belt 4 guided from the guide anchor 5, 7 is fixed to the floor of the vehicle body or the vehicle seat, and the tongue 6 can be engaged and disengaged. A buckle that is inserted into and engaged with, an electric motor 8 that is a drive means for rotating the spool of the seat belt retractor 3 to wind and withdraw the seat belt 4, 9 is a U-shaped frame, 9a is a frame 9 The left side wall, 9b is the right side wall of the frame 9, 10 is a spool, 10a is a rotation shaft of the spool 10, 11 is a lock mechanism, 12 is a deceleration sensing mechanism, 13 is a spring mechanism that is a spool winding attachment mechanism, and 13a is a spring. The case of the mechanism 13, 14 is a power transmission mechanism such as a planetary gear reduction mechanism or an external gear reduction mechanism, and 14 a is a case of the power transmission mechanism 14. 15 is a rotation sensor which is a rotation amount detection member, 16 is a controller (CPU), 17 is a pretensioner, and 18 is attached to the rotating shaft 10a of the spool 10 via the bush 10b so as to be rotatable integrally with the rotating shaft 10a. The rotation disk 15 of the rotation sensor 15, 19 is a bracket fixed to the right side wall 9 b of the frame 9, and 20 is disposed at a predetermined interval in the circumferential direction concentric with the rotation shaft 10 a and attached to the bracket 19. A pair of Hall elements (Hall ICs) 21 of the rotation sensor 15 that are electrically connected to the controller 16 are concentric with the rotation shaft 10a and N pole magnets 21a and S pole magnets 21b are alternately arranged. An annular magnet 22 of the rotating disk 18 holds the magnet 21 and slides on the rotating shaft 10a of the spool 10. A magnet holding member annular rotating disk 18 mounted concentrically integrally rotatable and the rotating shaft 10a with Lumpur 10.

  When the spool 10 rotates in the seat belt withdrawing direction, the rotary disk 18, that is, the magnet 21 also rotates in the same direction. Then, the pair of Hall elements 20 detect the N-pole magnet 21a and the S-pole magnet 21b, respectively, and output their detection signals to the controller 16. At this time, each Hall element 20 detects the N-pole magnet 21a and the S-pole magnet 21b alternately, whereby the polarity of the current of the detection signal of each Hall element 20 is switched and the detection of each Hall element 20 is detected. The phases of the signals are shifted from each other by a predetermined amount. Then, the controller 16 detects the rotation amount of the spool 10 by counting the number of times of switching the polarity of the current of the detection signal from each Hall element 20. Further, based on how the phases of the detection signals from the Hall elements 20 are shifted, it is determined whether the rotation direction of the spool 10 is the seat belt drawing direction or the seat belt winding direction. The controller 16 controls the belt tension of the seat belt 4 by controlling the driving of the electric motor 8 based on the rotation amount of the spool 10 and the rotation direction of the spool 10.

JP2009-1113718A.

  By the way, the rotation angle detected by the rotation sensor 15 varies due to variations in the installation positions of the pair of Hall elements 20. For example, as shown in FIG. 10, if the reference angle to be detected by the pair of Hall elements 20 is X °, the rotation angle detected by the pair of Hall elements 20 is actually X ° ± α °. . Here, X ° is a reference angle, and α ° is a variation. As a result, the detection accuracy of the rotation sensor 15 decreases. Therefore, in the seat belt retractor 3 described in Patent Document 1, variations in the installation positions of the pair of Hall elements 20 are reduced as much as possible, and the detection accuracy of the rotation sensor 15 is maintained at least within a practical range. Note that the variation in the rotation angle detected by the rotation sensor 15 is approximately the same.

However, in the seat belt retractor 3 described in Patent Document 1, the rotation disk 18 (that is, the magnet 21) of the rotation sensor 15 is provided so as to be integrally rotatable with the rotation shaft 10a of the spool 10. That is, the rotation speed of the spool 10 and the rotation speed of the magnet 21 are equal or approximately equal. For this reason, the rotation angle of the detected magnet 21 becomes smaller with respect to the predetermined number of times of switching the polarity of the current of the detection signal from each Hall element 20. Thus, when the detected rotation angle of the magnet 21 is small, the variation in the rotation angle detected by the rotation sensor 15 affects the detected rotation angle of the magnet 21. Therefore, in the seat belt retractor 3 described in Patent Document 1, the detection accuracy of the rotation sensor 15 can be practically used, but it is desirable to further improve.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a seat belt retractor capable of further effectively improving the detection accuracy of the rotation amount detection member and a seat belt provided with the seat belt retractor. Is to provide a device.

In order to solve the above-described problems, a seat belt retractor according to the present invention includes a spool that winds up a seat belt, a driving unit that rotates the spool, and a rotation amount detection member that detects the rotation amount of the spool. At least in the seat belt retractor in which the rotation amount by the spool is controlled by drivingly controlling the driving unit based on the rotation amount of the spool detected by the rotation amount detection member, the rotation amount detection member rotates. The rotating disk has a predetermined number of magnets arranged alternately in an N-pole magnet and an S-pole magnet and concentric with the rotating disk, and rotates together with the predetermined number of magnets. And a driven member capable of rotating integrally with the spool to rotate the spool. A speed increasing mechanism that has a transmission member that transmits to the driven member, increases the rotation speed of the transmission member and transmits it to the driven member, and increases the rotation of the spool to rotate the magnet. A magnetic detection member that detects a magnet located at a predetermined position among the predetermined number of magnets, and the rotation amount detection member is eccentric in a radial direction of the rotation shaft of the spool and the rotation shaft. When a large load is applied from the seat belt to the spool at an emergency position, the transmission member is disposed at a position away from the driven member by this load .

Further, a seat belt retractor according to the present invention, the together with the transmission member is to be transmission gear, a transmission gear in which the transmission member is engaged with the object transmission gear, the speed increasing mechanism and the object transmission gear the It is characterized by comprising a transmission gear.

  Furthermore, the seat belt device according to the present invention includes a seat belt retractor that winds up the seat belt, a tongue that is slidably supported by the seat belt pulled out from the seat belt retractor, and the tongue is detachable. In the seat belt device that includes at least a buckle to be joined and restrains an occupant by the seat belt, the seat belt retractor is any one of the seat belt retractors of the present invention described above.

  According to the seat belt retractor of the present invention thus configured, a speed increasing mechanism for rotating the magnet by increasing the rotation of the spool at a predetermined speed ratio is disposed between the rotation amount detecting member and the spool. Is done. Therefore, this speed increasing mechanism increases the rotation speed of the magnet as compared with the rotation speed of the spool, so that the reference angle to be detected by the rotation amount detection member is larger than the reference speed to be detected by the conventional rotation sensor. can do. Thereby, the dispersion | variation in the detection of a rotation amount detection member can be made small effectively. As a result, the detection accuracy of the rotation amount detection member can be further effectively improved.

Further, in the rotation amount detecting member is decentered in the radial direction of the rotary shaft and the rotary shaft of the spool position, when a large load is applied to said spool from said seat belt in an emergency, the transmission member is the object by the load It arrange | positions in the position of the direction away from a transmission member . Therefore, the rotation amount detection member does not function as a spool bearing as in the prior art. Thereby, it is possible to effectively suppress transmission of a large load applied from the seat belt to the spool in an emergency to the rotation amount detection member. As a result, the size of the rotation amount detection member in the thrust direction (the axial direction of the spool) can be reduced as compared with the related art.
Furthermore, since the large load described above is suppressed from being transmitted to the rotation amount detection member, the rotation amount detection member can be suppressed from being affected by this load. As a result, the detection accuracy of the rotation amount detection member can be improved.
Furthermore, when a large deceleration acts on the vehicle in an emergency, the occupant's inertial force applied to the seat belt is substantially forward, so the load direction is substantially constant. Therefore, the installation position of the rotation amount detection member can be easily set.
In this way, it is possible to realize a seat belt retractor that can improve the detection accuracy of the rotation amount detection member, reduce the load applied to the rotation amount detection member, and suppress an increase in size in the thrust direction.

  On the other hand, according to the seat belt device of the present invention, since the seat belt retractor of the present invention is provided, the belt tension of the seat belt can be controlled more accurately. Thereby, the passenger | crew of a seatbelt can be restrained efficiently according to a vehicle driving | running | working condition, the use condition of a seatbelt apparatus, etc. over a long period of time.

The 1st example of embodiment of the seatbelt retractor concerning this invention is shown partially, (a) is a perspective view, (b) is a right view in (a). It is a figure explaining the relationship between the direction of the load applied to a spool, and the installation position of a rotation sensor. (A) is a figure which shows a speed increasing mechanism, (b) is a figure explaining the dispersion | variation in the detection angle of the rotation sensor of the 1st example shown in FIG. It is a figure similar to FIG. 2 which shows the 2nd example of embodiment of this invention. (A) And (b) is a figure similar to FIG. 1 (a) and (b) which shows the 3rd example of embodiment of this invention. It is a figure which shows the seatbelt apparatus of patent document 1. It is a figure which takes the cross section partially and shows the seatbelt retractor of patent document 1. FIG. (A) is a diagram showing an annular magnet of the rotation sensor described in Patent Document 1, (b) is a partial view corresponding to the VIIIB part in (a), partially showing the rotation sensor described in Patent Document 1, (C) is sectional drawing which follows the VIIIC-VIIIC line | wire in (b). It is a figure explaining the detection of rotation by a rotation sensor. It is a figure explaining the dispersion | variation in the detection angle of the rotation sensor of patent document 1. FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 partially shows a first example of an embodiment of a seat belt retractor according to the present invention, in which (a) is a perspective view and (b) is a right side view in (a). Note that, in the constituent elements of the seat belt retractor and the seat belt apparatus of the first example, the same constituent elements as those of the seat belt retractor and the seat belt apparatus described in Patent Document 1 of FIGS. Detailed description thereof will be omitted.

  As shown in FIGS. 1A and 1B, the seat belt retractor 3 of the first example includes a rotation sensor 15 that is a rotation amount detection member disposed at a position eccentric from the rotation shaft 10 a of the spool 10. ing. The rotation sensor 15 includes a rotary disk 18 that is rotatably attached to the right side wall 9b of the frame, and a bracket 19 that is non-movably attached to the right side wall 9b of the frame.

  The rotating disk 18 includes an annular magnet holding member 22 and a magnet 21 that is integrally rotatable with the magnet holding member 22 and arranged in an annular shape. The annular magnet 21 is formed by alternately arranging N-pole magnets 21a and S-pole magnets 21b. Further, the magnet holding member 22 integrally has a cylindrical driven gear 23 (corresponding to a driven member) having external teeth 23 a arranged concentrically with the magnet holding member 22.

  Further, a transmission gear 24 (corresponding to a transmission member) is attached to the rotating shaft 10a of the spool 10 so as to be integrally rotatable with the rotating shaft 10a via a bush 10b. The transmission gear 24 has external teeth 24 a, and the external teeth 24 a mesh with the external teeth 23 a of the transmission gear 23.

  Although not shown in FIGS. 1 (a) and 1 (b), the bracket 19 has a pair of Hall elements (Hall ICs) 20, which are magnetic detection members, facing a part of the magnet 21 and Patent Document 1. It is attached in the same way. Each Hall element 20 detects a magnet 21 located at a predetermined position.

  Thus, in the seat belt retractor 3 of the first example, the rotation sensor 15 is disposed in the radial direction of the transmission gear 24 (that is, in the radial direction of the rotating shaft 10a). In that case, as shown in FIG. 2, when the meshing position of the external teeth 23a of the rotation sensor 15 and the external teeth 24a of the transmission gear 24 is such that a large load F is applied from the seat belt 4 to the spool 10 in the above emergency, With this load F, the transmission gear 24 (that is, the rotating shaft 10a) is arranged at a position in the direction away from the driven gear 23 (that is, the rotation sensor 15).

  Further, in the seat belt retractor 3 of the first example, the gear ratio between the outer teeth 23a of the driven gear 23 of the rotation sensor 15 and the outer teeth 24a of the transmission gear 24 is determined by the rotation of the driven gear 23 (that is, the magnet 21). Rotation) is set so as to be faster than rotation of the transmission gear 24 (that is, rotation of the spool 10). That is, the transmission gear 23 and the transmission gear 24 constitute a speed increasing mechanism 25 including a gear mechanism that rotates the magnet 21 by increasing the rotation of the spool 10 at a predetermined speed ratio. Therefore, the speed increasing mechanism 25 is disposed between the rotation sensor 15 and the rotation shaft 10a of the spool 10.

When the rotation of the magnet 21 is increased more than the rotation of the spool 10 by the speed increasing mechanism 25, the detected magnet 21 is detected with respect to a predetermined number of times of switching the polarity of the current of the detection signal from each Hall element 20. The rotation angle increases. Now, the rotation sensor 15 in the seat belt retractor 3 of the first example shown in FIG. 3B is compared with the rotation sensor 15 in the conventional seat belt retractor 3 shown in FIG. In that case, the inner and outer diameters of the magnet 21 of the rotation sensor 15 of the first example and the inner and outer diameters of the magnet 21 of the conventional rotation sensor 15 are equal, and the diameter of the circle of the detection point detected by the pair of Hall elements 20 is also the same. Suppose they are the same. In this case, in the rotation sensor 15 of the first example, the reference angle (that is, the reference angle to be detected) when the polarity of the current polarity of the detection signal from each Hall element 20 is the same number of switching times is the same. It is expressed by Y ° and is expressed by X ° in the conventional rotation sensor 15. Therefore, the rotation angle detected by the rotation sensor 15 of the first example is Y ° ± α °, and the rotation angle detected by the conventional rotation sensor 15 is X ° ± α °. At this time, since the rotation sensor 15 of the first example is accelerated by the speed increasing mechanism 25 and is larger than the rotation speed of the spool 10, the reference angle Y ° of the rotation sensor 15 of the first example is the conventional rotation sensor 15. Greater than the reference angle X ° (ie, Y °> X °).

Thus, since Y °> X °, the influence of the variation α ° on the reference angle Y ° of the rotation sensor 15 of the first example is that the variation α ° affects the reference angle X ° of the conventional rotation sensor 15. It becomes smaller than the influence. As a specific example, it is assumed that the rotation of the spool 10 is V ° / sec and the speed ratio of the speed increasing mechanism 25 is 2. In this case, the rotation of the magnet 21 of the rotation sensor 15 of this first example is performed. The speed is 2 V ° / sec which is twice the rotational speed V ° / sec of the spool 10. On the other hand, the rotation speed of the magnet 21 of the conventional rotation sensor 15 is V ° / sec, which is the same as that of the spool 10. Therefore, the variation per unit reference angle is (1.05 / 2V) ° in the rotation sensor 15 of the first example, and (1.05 / V) ° in the conventional rotation sensor 15. That is, since the influence of the variation on the detection angle of the rotation sensor 15 of the first example is (1.05 / 2V) ° / (1.05 / V) °, the detection angle by the rotation sensor 15 of the first example is The influence of the variation with respect to the reference angle to be detected is one half of the influence of the variation with respect to the reference angle to be detected in the detection angle by the conventional rotation sensor 15. That is, at the same detection angle, the variation of the rotation sensor 15 of the first example is 0.52.
5 degrees, and the variation of the conventional rotation sensor 15 is 1.05 degrees.

  The other configurations of the seat belt retractor 3 of the first example and the configuration of the seat belt device 1 are the same as those of the seat belt retractor 3 and the seat belt device 1 described in Patent Document 1.

  According to the seat belt retractor 3 of the first example configured as described above, the rotation of the spool 10 is doubled at a predetermined speed ratio between the rotation sensor 15 and the rotation shaft 10a of the spool 10 and transmitted to the magnet 21. A speed increasing mechanism 25 is disposed. Accordingly, the speed increasing mechanism 25 increases the rotational speed of the magnet 21 as compared with the rotational speed of the spool 10. Therefore, the reference angle Y ° to be detected by the rotational sensor 15 of the first example is determined using the conventional rotational sensor. 15 can be larger than the reference speed X ° to be detected. Thereby, the dispersion | variation in the detection of the rotation sensor 15 of a 1st example can be made small effectively.

  Further, the transmission gear 24 is disposed in a radial direction eccentric from the rotation shaft 10a of the spool 10 and in a direction in which the transmission gear 24 is separated from the driven gear 23 by a large load F applied to the spool 10 in an emergency. Therefore, the rotation sensor 15 does not function as a bearing for the spool 10 as in the prior art. Thereby, it is possible to effectively suppress transmission of the large load F applied from the seat belt 4 to the spool 10 in an emergency to the rotation sensor 15. As a result, the size of the rotation sensor 15 in the thrust direction (the axial direction of the spool 10) can be reduced compared to the conventional size. In addition, since the seat belt retractor 3 of the first example includes the rotation sensor 15, even if the rotation sensor 15 is provided, it is possible to effectively suppress an increase in the size of the seat belt retractor 3 in the thrust direction. In particular, since the rotation sensor 15 is eccentrically arranged with respect to the rotation shaft 10a of the spool 10 in the radial direction, the size of the seat belt retractor 3 in the thrust direction can be more effectively suppressed.

  Furthermore, since the large load F described above is suppressed from being transmitted to the rotation sensor 15, the rotation sensor 15 can be suppressed from being influenced by the load F. Thereby, the detection accuracy of the rotation sensor 15 can be improved.

  Furthermore, when a large deceleration acts on the vehicle in an emergency, the occupant's inertial force applied to the seat belt 4 is substantially forward, so the load direction F is substantially constant. Therefore, the installation position of the rotation sensor 15 can be easily set.

  In this way, it is possible to realize a seat belt retractor that can improve the detection accuracy of the rotation sensor 15 and reduce the load applied to the rotation sensor 15 and suppress an increase in size in the thrust direction.

  On the other hand, according to the seat belt device 1 of the present invention, since the seat belt retractor 3 of the first example is provided, the belt tension of the seat belt 4 can be controlled more accurately. Thereby, the passenger | crew of the seatbelt 4 can be restrained efficiently over a long period of time according to a vehicle running condition, the use condition of the seatbelt apparatus 1, etc.

  The other functions and effects of the seat belt retractor 3 of the first example and the functions and effects of the seat belt apparatus 1 are the same as those of the seat belt retractor 3 and the seat belt apparatus 1 described in Patent Document 1.

  FIG. 4 is a view similar to FIG. 2, showing a second example of the embodiment of the present invention.

In the first example shown in FIGS. 1 to 3A and 3B, the rotating disk 18 of the rotation sensor 15 is used.
4 is arranged eccentrically with respect to the rotation shaft 10a of the spool 10. As shown in FIG. 4, in the seat belt retractor 3 of the second example, the rotating disk 18 of the spool 10 It is arranged concentrically with the rotating shaft 10a.

In the seat belt retractor 3 of the second example, the speed increasing mechanism 25 is constituted by a planetary gear mechanism. That is, the driven gear 23 provided on the rotating disk 18 of the rotation sensor 15 is constituted by the sun gear 23b having the external teeth 23b ₁ . The sun gear 23b can be rotated integrally with the rotary disk 18 (that is, the magnet 21) and is disposed concentrically with the rotary shaft 10a. An internal gear 26 having internal teeth 26 a is disposed concentrically with the rotating shaft 10 a and is fixed to the right side wall 9 b of the frame 9. Further, planet gear 27 having external teeth 27a meshed with the internal teeth 26a of the external teeth 23b ₁ and the internal gear 26 of the sun gear 23b are arranged. A predetermined number (three in the illustrated example) of planet gears 27 are arranged at equal intervals in the circumferential direction. Each planet gear 27 is rotatably supported by a carrier 28. The carrier 28 is attached to the rotary shaft 10a so as to be integrally rotatable. Therefore, the carrier 28 can rotate integrally with the spool 10.

The other configurations of the seat belt retractor 3 and the seat belt apparatus 1 of the second example are the same as those of the second example described above. In the seat belt retractor 3 of the second example configured as described above, the spool 10 rotates. Then, the carrier 28 rotates through the rotating shaft 10a. Then, since the three planet gears 27 rotate, the sun gear 23b rotates. At this time, the rotation of the carrier 28 is increased at a predetermined speed ratio by the planetary gear mechanism, and the sun gear 23b rotates. That is, the rotation of the spool 10 is accelerated by the speed increasing mechanism 25 and transmitted to the rotating disk 18, and the rotation speed of the magnet 21 becomes larger than the rotation speed of the spool 10.

  According to the seat belt retractor 3 of the second example, since the magnet 21 of the annular rotating disk 18 in the rotation sensor 15 is disposed concentrically with the rotation shaft 10a of the spool 10, the size of the rotation sensor 15 is reduced. An increase in the radial direction of the rotating shaft 10a can be suppressed. In addition, since the speed increasing mechanism 25 disposed between the rotating shaft 10a of the spool 10 and the rotating disk 18 of the rotation sensor 15 is a planetary gear mechanism, the rotation sensor 15 is moved in the radial direction of the rotating shaft 10a. Furthermore, it can form compactly.

  The effects of the seat belt retractor 3 and the seat belt device 1 of the second example are substantially the same as those of the first example.

  FIGS. 5A and 5B are views similar to FIGS. 1A and 1B, showing a third example of the embodiment of the present invention.

In the first example shown in FIGS. 1 to 3A and 3B, the speed increasing mechanism 25 is a gear mechanism of a transmission gear 23 of the rotation sensor 15 and a transmission gear 24 fixed to the rotation shaft 10 a of the spool 10. However, as shown in FIGS. 5A and 5B, in the seat belt retractor 3 of the third example, the speed increasing mechanism 25 is configured by a belt transmission mechanism 29. That is, in the third example, a driven pulley 30 is provided in the same manner as the driven gear 23 on the magnet holding member 22 of the rotation sensor 15 instead of the driven gear 23 of the first example. Further, a transmission pulley 31 is provided on the rotating shaft 10 a of the spool 10 in the same manner as the transmission gear 24 instead of the transmission gear 24 of the first example. An endless belt 32 is wound around the driven pulley 30 and the transmission pulley 31. That is, the belt transmission mechanism 29 includes a driven pulley 30, a transmission pulley 31, and an endless belt 32. The endless belt winding radius of the transmission pulley 31 is set larger than the endless belt winding radius of the driven pulley 30. Accordingly, the rotation of the spool 10 is increased and transmitted to the magnet 21, and the rotation speed of the magnet 21 becomes larger than the rotation speed of the spool 10.

  Other configurations and other functions and effects of the seat belt retractor 3 and the seat belt device 1 of the third example are substantially the same as those of the first example.

  In addition, this invention is not limited to this, A various design change is possible in the range of the technical matter described in the claim.

  A seat belt retractor and a seat belt device according to the present invention include a seat belt retractor configured as a motor retractor that performs belt winding and belt withdrawal by driving and controlling the rotation of a spool with an electric motor, and a seat belt device including the seat belt retractor. In particular, the present invention can be suitably used for a seat belt retractor including a rotation amount detection member that detects a rotation amount of a spool and a seat belt device using the same.

DESCRIPTION OF SYMBOLS 1 ... Seat belt apparatus, 3 ... Seat belt retractor, 4 ... Seat belt, 6 ... Tongue, 7 ... Buckle, 8 ... Electric motor, 9 ... Frame, 10 ... Spool, 10a ... Rotating shaft, 11 ... Locking mechanism, 12 ... Deceleration sensing mechanism, 13 ... spring mechanism, 14 ... power transmission mechanism, 15 ... rotation sensor, 16 ... controller (CPU), 18 ... rotating disk, 19 ... bracket, 20 ... Hall element (Hall IC), 21 ... magnet, 21a ... N pole magnet, 21b ... S pole magnet, 22 ... Magnet holding member, 23 ... Drive gear, 23a ... External gear, 23b ... Sun gear, 23b ₁ ... External gear, 24 ... Power transmission gear, 24a ... External gear, 25 ... speed increasing mechanism,
26 ... Internal gear, 26a ... Internal gear, 27 ... Planet gear, 27a ... External gear, 28 ... Carrier, 29 ... Belt drive mechanism, 30 ... Driven pulley, 31 ... Drive pulley, 32 ... Endless belt

Claims (3)

The spool includes a spool for winding the seat belt, a driving unit for rotating the spool, and a rotation amount detection member for detecting the rotation amount of the spool. The rotation amount of the spool detected by the rotation amount detection member is In the seat belt retractor in which the amount of rotation by the spool is controlled by controlling the driving means based on
The rotation amount detecting member includes a rotating disk, and the rotating disk includes a predetermined number of magnets in which N-pole magnets and S-pole magnets are alternately arranged in an annular shape concentric with the rotating disk, and Having a predetermined number of magnets and a driven member that can rotate integrally;
A transmission member provided so as to be integrally rotatable with the spool and transmitting the rotation of the spool to the driven member;
A speed increasing mechanism for increasing the rotational speed of the transmission member and transmitting the speed to the driven member, increasing the rotation of the spool and rotating the magnet;
Among the predetermined number of magnets, a magnetic detection member that detects a magnet located at a predetermined position ,
The rotation amount detection member is configured such that when a large load is applied to the spool from the seat belt in an emergency at a position eccentric in the radial direction of the rotation shaft of the spool and the rotation shaft, A seat belt retractor, wherein the seat belt retractor is disposed at a position away from the driven member . The driven member is a driven gear, and the driven member is a transmission gear meshing with the driven gear,
The seat belt retractor according to claim 1, wherein the speed increasing mechanism includes the driven gear and the transmission gear. The seat includes at least a seat belt retractor that winds up the seat belt, a tongue that is slidably supported by the seat belt pulled out from the seat belt retractor, and a buckle that is detachably engaged with the tongue. In a seat belt device that restrains an occupant by a belt,
The seat belt apparatus according to claim 1 or 2, wherein the seat belt retractor is the seat belt retractor.

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