JP4618659B2 - Motorized seat belt retractor - Google Patents

Description

BACKGROUND OF THE INVENTION
[0001]
The present invention relates to a retractor having a load limiting device and a lock mechanism, in particular, a retractor having a load limiting device and a lock mechanism using a motor, a retractor having a new mechanical load limiter, and a new high voltage. The present invention relates to a motor retractor and a novel motor retractor having good current value rise characteristics when the motor is started.
[Prior art]
[0002]
In a vehicle emergency, a mechanical load limiting device using a torsion bar or the like has been used in a conventional seat belt retractor in order to limit the load applied to the shoulder and chest of the passenger.
[Problems to be solved by the invention]
[0003]
In the conventional mechanical load limiting device, the pull-out load of the webbing is set to a predetermined pull-out load for each vehicle and cannot be changed. Therefore, the appearance of a new retractor capable of adjusting the pull-out load of the webbing has been desired.
[Means for Solving the Problems and Effects of the Invention]
[0004]
In order to achieve this object, the motor type seat belt retractor according to the present invention is a spool that winds up a webbing when a motor is driven and a locking piece is operated only in an emergency such as sudden braking or collision. And the motor are rotationally coupled via a planetary gear mechanism provided coaxially with the spool shaft of the spool. On the other hand, the motor is not driven and is not rotationally connected to the spool during normal times (other than emergency such as sudden braking or collision). The Rukoto to this configuration, between the emergency spool and the motor when the transmission of force generated by the rotation of the spool in the pull-out force and the seatbelt generated by the rotation of the rotation shaft of the motor, the spool shaft of the spool Therefore, the rotational force of the rotating shaft of the motor can be used as a force for limiting the load . As a result , the setting range of the webbing pull-out load can be expanded and the webbing pull-out load can be arbitrarily set.
[0005]
Also, because the rotational axis of the motor itself has a rotational drag due to the moment of inertia due to the rotational drag generated by the rotation of the rotational axis of the motor, the pulling load of the webbing can be increased by actively utilizing this rotational resistance. Can be adjusted.
[0006]
Further, during normal times (other than emergency such as sudden braking or collision), the rotational force of the spool can be transmitted only to the emergency shaft without being transmitted to the rotating shaft of the motor.
[0007]
In particular, the motorized seat belt retractor is provided with a load limiting device for limiting the pull-out force of the webbing when the webbing is pulled out by the forward movement of the occupant when a car both emergency, the load limiting device, the electrical shorting of the motor by generating a good Ri rotary drag motor since the rotational force of the motor when the electrical short can be actively used as a load limiting device, without unnecessary that to provide an additional load limiting device, An inexpensive and small motor type seat belt retractor can be made.
[0008]
Also, it is switched depending on the predetermined time control an electrical short or electrical non-shorting motors, to switch the time to time and electrically non-shorting to electrically short-circuit the motor arbitrarily set Thus, it becomes possible to derive a pull-out load of a predetermined webbing.
[0009]
Moreover, when electrically non shorts, by the motor is energized, it is possible to take advantage of the belt Rukuashisu preparative limit the belt withdrawing force by the rotation torque of the motor, adjusts the rotation force of the motor in the non-shorting This makes it possible to expand the setting range of the webbing pull-out load.
[0010]
Moreover, when electrically non shorts, by energizing through a resistor to the motor shorted, lever changes the resistance value, it becomes possible to adjust the rotational drag of the motor in non-shorting, extraction of the webbing It becomes possible to expand the setting range of the load.
[0011]
Moreover, when electrically non shorts in to Rukoto the electrically disconnected state motor, since the rotation force of the motor in the non-short-circuit hardly particularly complicated mechanism also does not require, easily and inexpensively belt withdrawing load It is possible to expand the setting range.
[0012]
Further, load heavy limiting device, by including a gear to interlock the spool and the motor for taking up the webbing, by changing the addition to the gear ratio of the adjustment of the rotational drag of the motor, to adjust the withdrawal load of the webbing It becomes possible.
DETAILED DESCRIPTION OF THE INVENTION
[0013]
Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the size, shape, and arrangement relationship of each component are shown only schematically to the extent that the present invention can be understood, and the numerical conditions described below are merely examples. Please understand that. FIG. 1 is a sectional view showing an embodiment of the first invention of the retractor of the present invention.
[0014]
This retractor consists of the following components.
(1) Spool 1 for winding a webbing (not shown)
(2) Torsion bar (spool shaft) 2 which is twisted with a predetermined load fitted as a spool shaft 2
(3) Retractor base 3 that rotatably supports the spool 1 and the torsion bar 2
(4) Internal gear (internal gear) 4 fixed integrally to the retractor base 3 with screws or the like
(5) Three planetary gears (planetary gears) 5 (only one is shown in the figure) engaged with the internal teeth of the internal gear
(6) A carrier (output shaft) 6 which is a rotation center shaft of the planetary gear 5 and is integrally fitted to the torsion bar 2
(7) Sun gear (sun gear) 7 engaged with the planetary gear 5
(8) One-end closed hollow cylindrical rotor 8 in which the sun gear 7 is integrally formed at the same rotation center of the one-end closed hollow cylinder.
(9) A ring-shaped magnet 9 which is affixed to the inner surface of the cylindrical peripheral portion of the rotor 8 with an adhesive or the like and constitutes the main part of the brushless motor.
(10) A plurality of drive coils 10 constituting the main part of the brushless motor in the vicinity of the magnet 9
(11) Cover 11 covering the brushless motor unit
(12) A cylindrical bush shaft 12 that is provided outside the cover 11 and is fitted and mounted to the torsion bar 2.
(13) A return spring 13 that has one end fixed to the bush shaft 12 and wound several times and transmits a driving force to the torsion bar 2.
(14) The other end of the return spring 13 is fixed, and is integrally fixed to the cover 11 to cover the return spring 13.
(15) Control circuit (not shown) constituting the main part of the brushless motor for controlling the current of the drive coil 10
[0015]
Hereinafter, the structure of the retractor of the present invention will be described in more detail.
The retractor 100 of the present invention includes a mechanical EA (EA means energy absorption, and this term is used in a unified manner hereinafter) mechanism (corresponding to the mechanical load limiting device in the claims) and an electric EA mechanism ( And an electric load limiting device in the claims). The mechanical EA mechanism absorbs energy by a twisting phenomenon of a torsion bar when a torque exceeding a predetermined limit load is applied.
[0016]
On the other hand, the electric EA mechanism is performed by applying an assist force by a motor. These two mechanisms are used so as to complement each other.
[0017]
Hereinafter, the overall operation of the retractor of the present invention will be described.
In this retractor 100, when a control current is sent to the drive coil by the control circuit, a magnetic field is generated in the drive coil 10 to give a repulsive force to the magnet 9, and a rotational force is generated in the rotor 8 as a brushless motor. The rotational force of the rotor 8 causes the sun gear 7 to rotate around the torsion bar 2, and the three planetary gears 5 engaged with the sun gear 7 are given rotational force, and are fixed internal fixed to the retractor base 3. Since it is engaged with the internal teeth of the gear 4, the three planetary gears 5 rotate like planets in the internal gear 4 (see reference numerals 26 and 27 in FIGS. 2 and 3). By this rotation of the planetary gear, the carrier, which is the rotation shaft of the planetary gear, rotates together with the rotation of the planetary gear, and rotates the torsion bar integrated with the carrier. When the torsion bar rotates, the spool also rotates integrally.
[0018]
The bush shaft integrally provided at the end of the torsion bar rotates with the rotation of the torsion bar, and winds up the return spring in the urging direction or the urging force releasing direction. Since the other structure is the same as that of the conventional retractor, the description of the structure is omitted.
[0019]
Next, the configuration and operation of only the EA mechanism of the retractor of the present invention will be described. There are roughly two methods for mutually complementing the two EA mechanisms of the EA mechanism of the torsion bar and the EA mechanism of the motor assist load. In the first method, a positive motor assist load is applied by rotating the spool in a direction opposite to the twisting rotation direction of the torsion bar by a brushless motor.
[0020]
In the second method, a negative and positive motor assist load is applied by rotating the spool in both the forward rotation direction and the reverse direction of the torsion bar by a brushless motor. Since the brushless motor can be controlled to rotate by the control circuit, if the rotation is controlled as in the first method, for example, in the case of a retractor using a torsion bar with a limit load of 2.5 kN, the torsion bar is twisted and rotated. When the motor assist load is applied from 0 to 3 kN (kilonewtons) in the opposite direction, adding the EA effect of the motor assist load to the EA effect of the torsion bar is expected to achieve an overall EA effect of 2.5 kN to 5.5 kN it can.
[0021]
On the other hand, if rotation control is performed as in the second method, for example, in the case of a retractor using a 4 kN torsion bar, -1.5 kN in the direction opposite to the torsional rotation direction of the torsion bar and +1. When a motor assist load up to 5 kN is given, an EA effect from 2.5 kN to 5.5 kN can be expected as a whole. In this case, when downsizing the motor mounted on the retractor, the second method is preferable because a motor with a small output can be used. Further, if a Hall element is arranged around the coil, the rotational state of the rotor can be sensed. Next, an embodiment of the retractor according to the second invention will be described.
[0022]
FIG. 2 is an exploded perspective view showing an embodiment of the retractor according to the second invention. FIG. 3 is a diagram showing the engagement relationship of the gears of the retractor of the present embodiment. In FIG. 2, the explosive pretensioning mechanism is omitted in the drawing. Hereinafter, the configuration of the retractor according to the present embodiment will be described with reference to FIGS. This retractor 200 is comprised from the component as shown below.
[0023]
(1) Retainer 20
(2) DC motor 21 mounted integrally with retainer 20
(3) Motor gear 22 provided integrally with the motor shaft of the DC motor 21
(4) A first gear 23 supported by a projecting piece provided on the retainer 20 and engaged with the motor gear 22 (specifically, the first gear 23 is an integral two-stage gear (a large gear 23a and a small gear). 23b), the motor gear 22 engages with the large gear 23a)
(5) A second gear 24 (specifically, the second gear 24, which is supported by the projecting piece provided on the retainer 20) and engages with the first gear 23 (specifically, the small gear 23b). Step gear (consisting of a large gear 24a and a small gear 24b), and the small gear 23b engages with the large gear 24a)
(6) A third gear 25 (specifically, the third gear 25, which is engaged with the second gear 24 (specifically, the small gear 24b) is composed of an integral two-stage gear (a large gear 25a and a small gear 25b). The small gear 24b engages with the large gear 25a)
(7) Three planetary gears 26 that engage with the third gear 25 (specifically, the small gear 25b)
(8) The internal gear 27 that engages with the three planetary gears 26 on the inner teeth 27a formed on the inner side.
(9) External teeth 27b formed on the outer peripheral surface of the internal gear 27
(10) A locking piece 30 that engages with the external tooth 27b and locks the clockwise rotation of the internal gear 27.
(11) Lever 31 formed of a spring that supports the locking piece 30 at one end.
(12) A ring member 32 in which the other end of the lever 31 is formed in a curl shape.
(13) A convex annular member 33 around which the ring member 32 is wound (the annular member 33 is integrally formed at the same rotation center as the first gear 23).
(14) A friction piece 34 that protrudes from the peripheral edge of the top surface of the annular member 33 and applies a frictional force by pressing the ring member 32.
(15) Carrier 35 for placing three planetary gears 26
(16) Three pins 36 fixed to the carrier 35 by rotatably supporting the three planetary gears 26 on the carrier 35
(17) Deceleration plate 37 inserted between three pins 36 and three planetary gears 26 in a swingable manner
(18) The tip end portion 38a is passed through the rotation center hole of the carrier 35 and is integrally fitted at the root portion of the tip end portion 38a, and the tip end portion 38a is slidably inserted into the rotation center hole of the third gear. Spool 38
(19) Webbing W for constraining the body, one end of which is fixed to the spool 38 (the arrow A is the pulling direction of the webbing W, and the arrow B is the pulling direction of the webbing W)
(20) Cover 39 covering the entire gear group (21) A plurality of screws 40 for attaching the cover 39 to the retainer 20
(22) A control circuit (not shown) that controls connection of the DC motor 21 to short circuit or non-short circuit and controls the rotation axis of the DC motor 21 to rotate clockwise or counterclockwise.
[0024]
Hereinafter, the operation of the retainer of the present invention will be described using the above-described components.
4A and 4B are diagrams showing the operation of the present embodiment, in which FIG. 4A shows a state where the motor rotates clockwise (CW direction), and FIG. 4B shows a state where the motor rotates counterclockwise (CW direction). It is a figure which shows the state in the case of rotating in a (CCW direction).
[0025]
In the retractor 200, the locking piece 30 is separated from the external teeth 27b as shown in FIG. 3 and FIG. 4 (B) in normal times (except for emergency such as sudden braking or collision). Since the null gear 27 is not restrained, the rotational force of the carrier 35 is not transmitted to the third gear due to the characteristics of the planetary gear. Therefore, the rotational force of the spool 38 that is integrally fitted to the carrier 35 is not transmitted to the rotational shaft of the DC motor 21 that engages with the third gear.
[0026]
Next, in an emergency such as sudden braking or collision, the webbing W is wound up prior to the pre-pretension mechanism (explosive pretension mechanism) by an output signal from an ABS (anti-skid brake) mechanism (not shown) or a collision prediction device (not shown). Then, the mechanism for increasing the tension is actuated to rotate the rotating shaft of the DC motor 21 in the clockwise direction (arrow direction) as shown in FIG.
[0027]
Then, the clockwise rotational force of the motor gear 22 is transmitted to the first gear 23 as the counterclockwise (arrow direction) rotational force, and the locking piece 30 engages with the external teeth 27b of the internal gear 27 to internalize. The rotation of the gear 27 in the clockwise direction (arrow direction) is locked. As a result, the rotational force of the third gear 25 can be transmitted to the carrier 35 with which the spool 38 is integrally fitted. Further, the rotational force of the first gear 23 is transmitted to the second gear 24 as a rotational force in the clockwise direction (arrow direction), and the rotational force in the counterclockwise direction (arrow direction) is transmitted to the third gear 25.
[0028]
Accordingly, the counterclockwise rotation of the third gear 25 causes the small gear 25b integrated with the third gear 25 to rotate counterclockwise, and the rotational force in the clockwise direction (arrow direction) is applied to each of the three planetary gears 26. To communicate. The three planetary gears 26 rotate counterclockwise (arrow direction) like a planet around the small gear 25b while engaging with the internal teeth 27a of the internal gear 27 whose rotation is restricted by the locking piece 30. The carrier 35 supporting the three planetary gears 26 is rotated counterclockwise (arrow direction). Therefore, the spool 38 fitted to the carrier 35 rotates counterclockwise and winds the webbing W (in the direction of arrow B). Therefore, the clockwise rotational force of the DC motor 21 is transmitted as a rotational force for winding the webbing W.
[0029]
Next, an impact force is transmitted to the vehicle body due to the collision, an impact detection signal is output from an acceleration sensor (not shown) or a crash sensor (not shown), a gunpowder type pretension mechanism (not shown) is activated, and the webbing W is drawn into the retractor 200. This ensures the initial restraint of the passenger. Next, the webbing W is pulled out by the inertial force in the forward direction of the occupant (arrow A in FIG. 4A).
[0030]
At this time, as shown in FIG. 4A, since the locking piece 30 is in the state of locking the external teeth 27b, the force with which the webbing W is pulled out from the spool 38 is counterclockwise to the rotating shaft of the DC motor 21. Rotational force is transmitted in the direction (opposite to the arrow). If the DC motor 21 is in an energized state or a short-circuited state, a counter electromotive force is generated by the rotation of the rotating shaft, and a rotational drag force that prevents the rotation is generated. In the second invention, this rotational drag is to be actively used for the lock mechanism and the EA mechanism. Hereinafter, the characteristics of the rotational drag will be described with reference to the drawings.
[0031]
FIG. 5 shows the rotational resistance F [Nm] (unit: Newton meter) and time of the short-circuited DC motor from the time when the vehicle on which the occupant boarded collided with the wall (0 point in the figure) until the vehicle completely crashed. It is a graph which shows notionally the relationship with T [sec] (a unit is second), Comprising: The graph according to weight (Light, Middle, Heavy) is shown.
[0032]
FIG. 6 shows the rotational resistance F [Nm] (unit: Newton meter) and time of the short-circuited DC motor from the time when the vehicle on which the occupant boarded collided with the wall (0 point in the figure) until the vehicle completely crashed. FIG. 5 is a graph conceptually showing a relationship with T [sec] (unit is second), and shows graphs for each of collision speeds (Low Speed, Middle Speed, High Speed).
[0033]
As shown in FIG. 5, the lighter the weight, the lower the rising slope of the curve (solid line graph on the drawing), and the heavier the weight, the higher the rising slope of the curve (double-dotted line graph on the drawing). It can be seen that when the body weight is medium, the rising slope of the curve is an intermediate slope between the light weight and the heavy weight.
[0034]
In addition, the slope of falling falls gently regardless of the weight difference. From this result, if the rotational drag is used for the EA mechanism, the EA load increases relatively gently for a passenger with a light weight, so that the total load applied to the body becomes relatively small.
[0035]
On the other hand, since the EA load increases relatively steeply for a heavy passenger, the total load applied to the body is relatively large. The EA load decrease gradient falls gently regardless of the weight difference, and soft landing is possible.
[0036]
Further, as shown in FIG. 6, the higher the collision speed at the time of collision with the wall of the vehicle, the greater the webbing pull-out speed and the higher the load limit value (EA load limit value) of the rotational drag F (two on the drawing). As the collision speed is slower, the load limit value of the rotational drag F is lower (solid line graph on the drawing). That is, since the load limit value increases or decreases depending on whether the collision speed is fast or slow, an ideal occupant restraint capability can be exhibited.
[0037]
In a conventional mechanical EA mechanism, for example, a torsion bar, the gradient of rising of the EA load is constant and the load limit value is also constant regardless of the difference in weight or the collision speed.
[0038]
The load limit value can be arbitrarily set by various methods as follows. For example, by changing the gear ratio for transmitting the rotation of the spool 38 to the DC motor 21, it is possible to arbitrarily set the load limit value, rising gradient, and falling gradient of the rotational drag F.
[0039]
If the DC motor 21 is energized or short-circuited via a resistor, the load limit value, rising slope, and falling slope of the rotational drag can be arbitrarily adjusted by changing the resistance value. For example, the higher the resistance value, the lower the load limit value, the gentler the rising slope and the steeper the falling slope. In this case, it is also possible to connect resistors having different resistance values so as to be selectable on the circuit, and to automatically connect to the optimum resistor depending on the severity. This makes it possible to expect more ideal restraint performance.
[0040]
If a fuse is connected in addition to connecting a resistor, the EA mechanism is released when the predetermined current value is exceeded, and the EA load can be reduced. Similarly to the first method and the second method of the above-described embodiment, a weak rotational force (in the arrow direction in FIG. 4A) may be applied so that the webbing W is drawn into the rotation shaft of the DC motor 21 by energization. For example, a positive motor assist load can be applied to the rotational drag, and conversely, a weak rotational force (in the direction opposite to the arrow in FIG. 4A) is applied to the rotational shaft of the DC motor 21 so as to pull out the webbing W. By doing so, a negative motor assist load can be applied to the rotational drag. Also, the load limit value, rising slope, and falling slope can be adjusted by replacing motors with different outputs.
[0041]
As another method for adjusting the load limit value, the rising slope, and the falling slope, a pulse-shaped rectangular wave is created by arbitrarily changing the time t1 and the non-short-circuited t2 for short-circuiting the DC motor 21, respectively. By controlling the short circuit / non-short circuit of the DC motor 21 with the rectangular wave, the load limit value, rising gradient, and falling gradient of the rotational drag can be arbitrarily set. For example, as t1 is made longer than t2, the load limit value is higher, the rising slope becomes steeper, and the falling slope becomes gentler. Further, the load limit value becomes lower as t2 becomes longer than t1, the rising slope becomes gentle, and the falling slope becomes steeper.
[0042]
The rotational drag used here includes rotational drag due to the moment of inertia of the rotating shaft of the motor itself. Therefore, it is possible to electrically open the motor without short-circuiting it , that is , to make it a disconnected state, and to implement the load limiting device by actively utilizing only the rotational drag due to the moment of inertia. In this case, the adjustment range of the load limiting device can also be changed by adjusting the gear ratio.
[0043]
The timing for starting the EA mechanism can also be performed by an ECU that instructs ignition to an airbag or a pretensioner.
Further, it is preferable to adjust the load limit value, the rising gradient, and the falling gradient appropriately by looking at the drawing characteristics of the webbing W in an experiment using an actual vehicle using a dummy. In addition, if a rotating shaft provided with a magnet is provided in the copper tube instead of the DC motor 21, it is not necessary to short-circuit, so that the EA mechanism can be provided with an inexpensive and simple structure.
[0044]
Further, it is more effective when these EA mechanisms are used in combination with various preten mechanisms such as a buckle preten. Moreover, a vehicle sensor can be incorporated in a retractor and used as an EA switch.
Further, even with the retractor as in the embodiment shown in FIG. 1 described above, it is possible to add a method of using the rotational drag of the motor short-circuited as the EA mechanism by applying the second invention.
[0045]
As described above, if the motor type seat belt retractor according to the present invention is used, the setting range of the webbing pull-out load can be expanded and the webbing pull-out load can be arbitrarily set. Become.
[Brief description of the drawings]
FIG. 1 is a sectional view showing an embodiment of a first invention of a retractor according to the present invention.
FIG. 2 is an exploded perspective view showing an embodiment of a retractor according to the second invention.
FIG. 3 is a view showing a gear engagement relationship in the embodiment of the retractor according to the second invention.
FIG. 4 is a view showing the operation of the embodiment of the retractor according to the second invention, wherein (A) is a view showing a state where the motor rotates in the clockwise direction (CW direction); ) Is a diagram showing a state where the motor rotates counterclockwise (CCW direction).
FIG. 5 shows the rotational resistance F [Nm] (unit: Newton meter) and time of a short-circuited DC motor from the time when a vehicle on which an occupant has collided with a wall (0 point in the figure) until the vehicle completely crashes. It is a graph which shows notionally the relationship with T [sec] (a unit is second), Comprising: The graph according to weight (Light, Middle, Heavy) is shown.
FIG. 6 shows the rotational resistance F [Nm] (unit: Newton meter) and time of a short-circuited DC motor from the time when the vehicle on which the occupant boarded hits the wall (0 point in the figure) until the vehicle completely crashes. FIG. 5 is a graph conceptually showing a relationship with T [sec] (unit is second), and shows graphs for each of collision speeds (Low Speed, Middle Speed, High Speed).
[Explanation of symbols]
1: Spool, 2: Torsion bar, 3: Retractor base, 4: Internal gear, 5: Planetary gear, 6: Carrier, 7: Sun gear, 8: Rotor, 9: Magnet, 10: Drive coil, 11: Cover , 12: bush shaft, 13: return spring, 14: spring cover, 20: retainer, 21: DC motor, 22: motor gear, 23: first gear, 23a, 24a, 25a: large gear, 23b, 24b, 24: Second gear, 25: third gear, 25b: small gear, 26: planetary gear, 27: internal gear, 27a: internal teeth, 27b: external teeth, 30: locking piece, 31: lever, 32: ring Member, 33: annular member, 34: friction piece, 35: carrier, 36: pin, 37: reduction plate, 38: spool, 39: cover, screw 40,200: retractor

Claims (6)

A spool for winding the webbing;
A motor that stops normally and drives in an emergency;
A large gear that is coaxially rotatable with the spool shaft of the spool and that transmits the rotational force of the motor, and a small gear having a smaller diameter than the large gear and integrally rotating with the large gear. A gear, an internal gear provided coaxially with the spool shaft of the spool and having internal teeth and external teeth, a planetary gear engaged with the small gear and the internal teeth of the internal gear, and A spool shaft of the spool is integrally fitted so as to be rotatable, and has a carrier that rotatably supports the planetary gear, and between the spool and the motor, the rotational force of the motor and the spool A planetary gear mechanism for transmitting rotational force;
A locking piece provided so as to be engageable with the external teeth of the internal gear and preventing rotation of the internal gear in the webbing pull-out direction when engaged with the external teeth of the internal gear;
A lever that is operated by the rotational force of the motor to engage the locking piece with an external tooth of the internal gear;
A load limiting device for limiting the pull-out load of the webbing in an emergency,
The load limiting device, motorized seat belt retractor, characterized in that to limit the pull-out load of the webbing by rotating anti force generated by the rotation of the rotation shaft of the motor. The motor type seat belt retractor according to claim 1, wherein the load limiting device generates the rotational drag by an electrical short circuit of the motor. Before yn heavy restriction device, motorized seat belt retractor according to claim 2, characterized in that to switch by a predetermined time controlled electrical short or electrical non-shorting the motor. The motor type seat belt retractor according to claim 3, wherein the motor is in an energized state during the electrical non-short circuit . The motor type seat belt retractor according to claim 4 , wherein the motor is energized through a resistor during the electrical non-short circuit . The motor type seat belt retractor according to any one of claims 1 to 5 , wherein the load limiting device includes a gear that interlocks the spool and the motor .

Images