JP7329379B2 - Seatbelt retractor and seatbelt device - Google Patents

Description

The present invention relates to a seatbelt retractor and a seatbelt device.

A seat belt device installed in a vehicle such as an automobile restrains the occupant with the seat belt in an emergency (for example, when a large vehicle deceleration acts on the vehicle during a collision while the seat belt is worn). To prevent an occupant from jumping out of a seat.

Such a seatbelt device is provided with a seatbelt retractor that retracts the seatbelt so that it can be withdrawn. In this seatbelt retractor, the seatbelt is wound around a spool when the seatbelt is not worn, but is pulled out and worn by the occupant when the seatbelt is worn. In an emergency as described above, the locking means of the seat belt retractor is activated to prevent the spool from rotating in the belt withdrawing direction, thereby preventing the withdrawal of the seat belt. be.

When an occupant is restrained by a seatbelt in an emergency such as a vehicle collision, a large vehicle deceleration occurs, and the occupant tries to move forward due to large inertia. Therefore, a large load is applied to the seat belt, and the occupant receives a large force from the seat belt. Although this force is not particularly problematic for the occupant, it is desirable to limit it if possible.

Therefore, the development of a seat belt retractor equipped with an energy absorption mechanism (hereinafter also referred to as an EA mechanism) that absorbs and mitigates the energy of the occupant by limiting the load acting on the seat belt in an emergency with the seat belt fastened is progressing. . As one of such seat belt retractors, there is a retractor equipped with a mechanical EA mechanism that utilizes the force generated by twisting the torsion bar and an electric EA mechanism that utilizes the force generated by an electrical short circuit of the motor. (See Patent Document 1, for example).

JP-A-2001-270423

However, in the conventional technology, if the load generated by the motor becomes excessive for some reason such as a failure, there is a risk that an unintended excessive load will act on the seatbelt.

Accordingly, the present disclosure provides a seatbelt retractor and a seatbelt device that can prevent an excessive load from acting on the seatbelt.

This disclosure is
a spool for winding the seat belt;
a locking mechanism that allows rotation of the spool when not in operation and prevents rotation of the spool in the seat belt withdrawal direction when in operation;
a first energy absorption mechanism deformed by rotation of the spool in the pull-out direction and rotation prevention by the lock mechanism;
a power transmission mechanism that adds a second load generated by power of a motor to a first load generated by deformation of the first energy absorption mechanism;
a second energy absorption mechanism that reduces the limit load, which is increased by adding the second load to the first load, by its own deformation ,
The power transmission mechanism has a clutch that blocks transmission of force from the spool to the motor and allows transmission of force from the motor to the spool,
The clutch provides a seat belt retractor that is connected to the output shaft of the motor via the second energy absorbing mechanism . The present disclosure also provides a seatbelt device including the seatbelt retractor.

According to the technique of the present disclosure, it is possible to provide a seatbelt retractor and a seatbelt device that can prevent an excessive load from acting on the seatbelt.

It is a figure which illustrates the structure of the seatbelt apparatus in one Embodiment. 1 is a block diagram illustrating the configuration of a seat belt retractor in one embodiment; FIG. FIG. 5 is a diagram illustrating the behavior of limit load with respect to stroke of the spool; It is a front view of a seat belt retractor in a 1st embodiment. It is a right view of the seat belt retractor in 1st Embodiment. It is a left view of the seat belt retractor in 1st Embodiment. FIG. 6 is a diagram showing a cross-sectional view of the seat belt retractor in the first embodiment taken along line AA (see FIG. 6); It is an exploded perspective view of a seat belt retractor in a 1st embodiment. It is a side view of a clutch. It is an exploded perspective view of a clutch. FIG. 10 is a diagram showing a clutch off state (clutch pawl closed state) along arrows BB (see FIG. 9); FIG. 10 is a diagram showing an on-operation of the clutch (clutch pawl open state) by arrows BB (see FIG. 9); FIG. 6 is a diagram showing a cross section of the seat belt retractor in the second embodiment, taken along line AA (see FIG. 6). It is an exploded perspective view of a seat belt retractor in a 2nd embodiment. It is a perspective view of a connect gear in a second embodiment. FIG. 6 is a diagram showing a cross section of the seat belt retractor in the third embodiment by arrow AA (see FIG. 6). It is an exploded perspective view of a seat belt retractor in a 3rd embodiment. It is a perspective view of the connect gear in 3rd Embodiment. It is an exploded perspective view of a seat belt retractor in a 4th embodiment.

Hereinafter, embodiments according to the present disclosure will be described with reference to the drawings.

FIG. 1 is a diagram illustrating the configuration of a seatbelt device according to one embodiment of the present disclosure. A seat belt device 101 shown in FIG. 1 is an example of a seat belt device mounted on a vehicle. The seatbelt device 101 includes, for example, a seatbelt 104, a retractor 103, a shoulder anchor 106, a tongue 107, and a buckle .

The seat belt 104 is an example of a seat belt that restrains the occupant 111 sitting on the seat 102 of the vehicle, and is a belt-like member that is retractably wound around the retractor 103 . A seat belt is also called webbing. A belt anchor 105 at the tip of the seat belt 104 is fixed to the seat 102 or the vehicle body near the seat 102 .

The retractor 103 is an example of a seat belt retractor capable of retracting or withdrawing the seat belt 104 . The retractor 103 restricts the seat belt 104 from being withdrawn from the retractor 103 when an acceleration/deceleration or vehicle angle equal to or greater than a predetermined value is detected, such as when the vehicle collides. The retractor 103 is fixed to the seat 102 or the vehicle body near the seat 102 . Retractor 103 is an example of a seat belt retractor.

The retractor 103 has a function of winding the seat belt 104 around a spool by the power of the motor 103a. For example, before a vehicle collision, the retractor 103 operates a motor 103a based on a signal from a sensor such as a millimeter-wave radar to wind the seatbelt 104 on a spool and apply pretension to the seatbelt 104 so that the seatbelt 104 is retracted. Quickly restrain the occupant by Further, the retractor 103 operates the motor 103a to wind the seat belt 104 on the spool, for example, when the tongue 107 and the buckle 108 are disconnected. The retractor 103 operates, for example, a motor 103a to adjust the tension of the seat belt 104 according to the driving situation (state of the vehicle), thereby reducing the restraint of the occupant by the seat belt 104 and the comfort of wearing the seat belt 104. improve their individuality.

The state of the vehicle includes, for example, whether or not the seat belt 104 is pulled out, whether or not the occupant 111 is present, the traveling speed of the vehicle, the acceleration of the vehicle, the steering operation, the accelerator operation, the brake operation, the buckle 108 operation, the door operation, and the occupant's operation. This refers to a state that represents possible operation input of an in-vehicle selection switch, etc.

The shoulder anchor 106 is an example of a belt passer through which the seat belt 104 passes, and is a member that guides the seat belt 104 pulled out from the retractor 103 toward the shoulder of the occupant 111 . A shoulder anchor 106 is fixed to the seat 102 or to the vehicle body near the seat 102 .

The tongue 107 is an example of a belt passer through which the seat belt 104 passes, and is a component slidably attached to the seat belt 104 guided by the shoulder anchor 106 .

Buckle 108 is a component into which a flat locking portion of tongue 107 attached to seat belt 104 is inserted and removed, and tongue 107 is detachably connected. The buckle 108 is fixed, for example, to the seat 102 or the vehicle body near the seat 102 .

With the tongue 107 connected to the buckle 108 , the portion of the seat belt 104 between the shoulder anchor 106 and the tongue 107 is the shoulder belt portion 109 that restrains the chest and shoulders of the occupant 111 . With the tongue 107 connected to the buckle 108 , the portion of the seat belt 104 between the belt anchor 105 and the tongue 107 is the lap belt portion 110 that restrains the waist of the occupant 111 .

FIG. 2 is a block diagram illustrating the configuration of a seat belt retractor in one embodiment according to the present disclosure. The retractor 1 and motor 12 shown in FIG. 2 correspond to the retractor 103 and motor 103a shown in FIG. 1, respectively. The retractor 1 is a seat belt retractor that includes at least a spool 4 , a lock mechanism 6 , a first EA mechanism 53 , a power transmission mechanism 21 and a second EA mechanism 54 .

The spool 4 is a member that is rotatably supported by a frame (not shown) and winds the seat belt 104 so that it can be pulled out.

The lock mechanism 6 permits the rotation of the spool 4 when not in operation, and prevents the rotation of the spool 4 in the withdrawal direction of the seat belt 104 when in operation. The lock mechanism 6 prevents rotation of the spool 4 in the seat belt 104 withdrawal direction by locking the first EA mechanism 53 when activated.

The first EA mechanism 53 is deformed by the rotation of the spool 4 in the direction in which the seat belt 104 is pulled out and the rotation prevention by the lock mechanism 6 . The first EA mechanism 53 is an example of a first energy absorption mechanism that limits the load acting on the seat belt to absorb and mitigate the energy of the occupant.

For example, in an emergency such as a vehicle collision, at least one of the pretensioner 8 and the motor 12 operates to rotate the spool 4 in the belt winding direction, thereby strongly winding the seat belt 104 onto the spool 4 . After that, the seat belt 104 tends to be pulled out from the spool 4 by the occupant moving forward due to inertia. At this time, since the first EA mechanism 53 is locked by the operation of the lock mechanism 6, the rotation of the spool 4 in the belt withdrawing direction is prevented. However, since the spool 4 tries to rotate in the belt withdrawing direction, the first EA mechanism 53 is deformed due to the rotation of the spool 4 in the withdrawing direction of the seat belt 104 and the rotation prevention by the lock mechanism 6 . The deformation of the first EA mechanism 53 limits the load acting on the seat belt 104 pulled out from the spool 4 . That is, the occupant's energy is absorbed and relaxed by the deformation of the first EA mechanism 53 .

The power transmission mechanism 21 combines a first load (hereinafter also referred to as base load BN) generated by deformation of the first EA mechanism 53 with a second load (hereinafter also referred to as assist load AN) generated by the power of the motor 12. ) is added. The assist load AN may include not only the load generated only by the power of the motor 12, but also the load generated by the friction of the reduction mechanism that reduces and transmits the rotation of the output shaft 12a of the motor 12. Loads generated by deformation of the EA mechanism 54 may also be included. The number of reduction mechanisms may be one or plural. FIG. 2 shows the first speed reduction mechanism 51 and the second speed reduction mechanism 52 . By adding the assist load AN to the base load BN, a limit load (hereinafter also referred to as limit load LN) is generated. The retractor 1 limits the load acting on the seat belt 104 with the limit load LN thus generated.

The second EA mechanism 54 reduces the limit load LN, which increases by adding the assist load AN to the base load BN, through its own deformation. Therefore, even if the assist load AN generated by the power of the motor 12 becomes excessive for some reason such as a failure during operation of the motor 12, the deformation of the second EA mechanism 54 reduces the limit load LN. Therefore, it is possible to prevent an excessive load from acting on the seat belt 104 . The second EA mechanism 54 is an example of a second energy absorption mechanism that limits the load acting on the seat belt and absorbs and relaxes the energy of the occupant.

The second EA mechanism 54 has a structure that cuts off the connection between the motor 12 and the spool 4, for example, when the limit load LN or the assist load AN reaches a set value (load value preset in design). . Since the connection between the motor 12 and the spool 4 is cut by the second EA mechanism 54, the assist load AN cannot be applied to the base load BN, so the limit load LN can be reduced.

The connection between the motor 12 and the spool 4 is cut, for example, by breaking the second EA mechanism 54 itself. Thereby, the structure for reducing the limit load LN can be simplified. For example, the second EA mechanism 54 has a shear pin inserted in the power transmission path between the motor 12 and the spool 4 and disconnects the connection between the motor 12 and the spool 4 by shearing the shear pin.

FIG. 3 is a diagram illustrating the behavior of the limit load LN with respect to the stroke of the spool 4. FIG. The horizontal axis represents the relative rotation amount (stroke) of the spool 4 in the belt withdrawing direction after the lock mechanism 6 is locked, and the vertical axis represents the limit load LN generated by the retractor 1 .

As shown in FIG. 3, the power transmission mechanism 21 generates a limit load LN by adding an assist load AN generated by the power of the motor 12 to a base load BN generated by deformation of the first EA mechanism 53. do. The limit load LN is approximately equal to the sum of the base load BN and the assist load AN.

In a state where the limit load LN has not reached the upper limit load Lb, the assist load AN is directly added to the base load BN. The upper limit load Lb is determined by adding the first limit load N1 by the first EA mechanism 53 and the second limit load N2 by the second EA mechanism 54 . The first limit load N1 is the maximum load that can be generated by deformation of the first EA mechanism 53, and the second limit load N2 is the maximum load until deformation or breakage of the second EA mechanism 54 occurs. This is the maximum load that can be generated by powering up the motor 12 . On the other hand, even if the limit load LN becomes excessive for some reason, when it reaches the upper limit load Lb as shown by the waveform c, it begins to decrease due to the deformation or breakage of the second EA mechanism 54. can be prevented from acting on the seat belt 104. A decrease in the limit load LN is caused by a decrease in the assist load AN due to deformation or breakage of the second EA mechanism 54 .

In addition, even if the limit load LN decreases due to the deformation or breakage of the second EA mechanism 54, the base load BN continues to be generated due to the deformation of the first EA mechanism 53. Therefore, the limit load LN exceeds the base load BN. Decrease to the lower limit. Therefore, at least the base load BN can be secured. That is, since the load acting on the seat belt 104 can be limited by the first limit load N1 by the first EA mechanism 53, an excessive load acts on the seat belt 104 even if the second EA mechanism 54 breaks. can be prevented.

Even if the assist load AN cannot be added to the base load BN due to some abnormality (for example, a failure of the power transmission mechanism 21) due to a vehicle collision or the like, the limit load LN is transferred to the first load by the first EA mechanism 53. The limit load N1 can be limited to the upper limit. That is, since the load acting on the seat belt 104 can be limited by the first limit load N1 by the first EA mechanism 53, even in an abnormal state where the assist load AN cannot be applied, it is possible to prevent an excessive load from acting on the seat belt 104. can be prevented.

Further, the retractor 1 is provided with a control unit 10 (see FIG. 2) that adjusts the assist load AN by controlling the motor 12, so that the limit load LN can be flexibly adjusted within a range equal to or lower than the upper limit load Lb.

For example, the controller 10 can adjust the rising speed of the limit load LN by controlling the motor 12 to adjust the rising speed of the assist load AN, as shown by waveforms f, g, and h in FIG. Waveform h indicates the case where the motor 12 is controlled so that the assist load AN rises faster than waveform f, and waveform g indicates the case where the motor 12 is controlled so that the assist load AN rises slower than waveform f. Indicates when to control.

Further, for example, the control unit 10 may increase or decrease the positive assist load AN added to the base load BN by controlling the motor 12 . Thereby, as shown by waveforms f, g, and h in FIG. 3, the limit load LN can be increased or decreased within the range from the first limit load N1 to the upper limit load Lb. Further, the control unit 10 can adjust the limit load LN to the first limit load N1 by stopping the motor 12 and setting the assist load AN to zero. Further, the control unit 10 can adjust the limit load LN to be lower than the first limit load N1 by controlling the motor 12 so that the negative assist load AN is added to the base load BN. For example, the control unit 10 can increase or decrease the limit load LN in a range lower than the first limit load N1 by controlling the motor 12 to increase or decrease the negative assist load AN added to the base load BN.

Thus, the control unit 10 can generate a flexible limit load LN within a range equal to or less than the upper limit load Lb by controlling the motor 12 . Therefore, for example, the control unit 10 can generate an appropriate limit load LN according to the collision conditions and the physique of the passenger.

Next, the configuration shown in FIG. 2 will be described in more detail.

Motor 12 and spool 4 are preferably interconnected via a second EA mechanism 54 . As a result, the power of the motor 12 is transmitted to the spool 4 via the second EA mechanism 54, so the magnitude of the assist load AN is accurately limited to the second limit load N2 or less by the second EA mechanism 54. can.

In the configuration shown in FIG. 2, the speed reduction mechanisms that reduce the speed of the rotation of the rotating shaft of the motor 12 and transmit the speed are the first speed reduction mechanism 51 and the second speed reduction mechanism that are connected to each other via the second EA mechanism 54. 52. That is, the second EA mechanism 54 is inserted and arranged in the power transmission path between the first speed reduction mechanism 51 and the second speed reduction mechanism 52 . By connecting the second EA mechanism 54 and the spool 4 via the second speed reduction mechanism 52, compared to the form of connection without the second speed reduction mechanism 52, the second EA mechanism 54 reduces the 2 can be set small, the second EA mechanism 54 can be made smaller.

For example, consider a case where the upper limit load Lb is set to 4 kN (kilonewtons). Assuming that the first limit load N1 by the first EA mechanism 53 is 1 kN, the second limit load N2 by the second EA mechanism 54 is 3 kN ( =Lb-N1). On the other hand, in the form of connection through the second speed reduction mechanism 52, when the speed reduction ratio R of the second speed reduction mechanism 52 is 2, the second limit load N2 by the second EA mechanism 54 is 1 .5 kN (=(Lb-N1)/R). Therefore, the second EA mechanism 54 can be made smaller in the form of connection via the second reduction gear mechanism 52 than in the form of connection without the second reduction gear mechanism 52 . For example, when the second EA mechanism 54 sets the second limit load N2 or the upper limit load Lb by deformation or breakage of the shear pin, the shear pin can be thinned. Easy to lay out.

The first deceleration mechanism 51 decelerates the rotation of the output shaft 12a of the motor 12 and transmits it to the second EA mechanism 54 side. The second deceleration mechanism 52 decelerates the rotation generated by the second EA mechanism 54 and transmits it to the spool 4 side.

In addition, the power transmission mechanism 21 preferably has a clutch 25 that blocks transmission of force from the spool 4 to the motor 12 and allows transmission of force from the motor 12 to the spool 4 . By providing the clutch 25 that cuts off transmission of force from the spool 4 to the motor 12 , for example, it is possible to prevent transmission of the powerful winding torque of the seat belt 104 by the pretensioner 8 at the time of collision to the motor 12 . Further, when the rotating shaft of the spool 4 and the output shaft of the motor 12 are connected, when the occupant pulls out the seat belt 104 from the retractor 1 or causes the retractor 1 to wind the seat belt 104, the load of the motor 12 is reduced to the seat belt 104. It is transmitted to the passenger who operates the belt 104 . As a result, the occupant cannot pull out or wind up the seat belt 104 smoothly, which may cause discomfort to the occupant. On the other hand, the clutch 25 is a one-way clutch that cuts off transmission of torque from the spool 4 to the motor 12 and transmits torque from the motor 12 to the spool 4 . Therefore, transmission of rotational force from the spool 4 to the motor 12 is blocked by the clutch 25, so that the occupant can smoothly withdraw the seat belt 104 from the retractor 1 or cause the retractor 1 to wind the seat belt 104 smoothly.

The clutch 25 cuts off force transmission from the spool 4 to the output shaft 12a when the output shaft 12a of the motor 12 is not rotating, and transmits power from the output shaft 12a to the spool 4 when the output shaft 12a is rotating. allow transmission of force to As a result, the control unit 10 operates the motor 12 to rotate the output shaft 12a, thereby turning on the clutch 25 (allowing transmission of force from the output shaft 12a to the spool 4). On the other hand, the control unit 10 stops the motor 12 to stop the rotation of the output shaft 12a, so that the clutch 25 can be turned off (transmission of force from the spool 4 to the output shaft 12a can be cut off). That is, the control unit 10 can turn on the clutch 25 in synchronization with the operation of applying the assist load AN.

In the form shown in FIG. 2, the first EA mechanism 53 has a first portion 55 that engages the spool 4 and a second portion 56 that is locked by the locking mechanism 6 . The power transmission mechanism 21 transmits the assist load AN to the first portion 55 side. By transmitting the assist load AN to the side of the first portion 55 that engages with the spool 4, the assist load AN can be efficiently added to the base load BN.

Next, a specific configuration of the retractor 1 will be described.

FIG. 4 is a front view of the seat belt retractor in the first embodiment. FIG. 5 is a right side view of the seat belt retractor in the first embodiment. FIG. 6 is a left side view of the seat belt retractor in the first embodiment. FIG. 7 is a diagram showing a cross-section of the seat belt retractor in the first embodiment taken along line AA (see FIG. 6). FIG. 8 is an exploded perspective view of the seat belt retractor in the first embodiment.

A retractor 1A shown in FIGS. 4 to 8 is an example of a seat belt retractor, and a specific example of the retractor 1 shown in FIG. The retractor 1A includes a first EA mechanism 53A, which is an example of the first EA mechanism 53, and a second EA mechanism 54A, which is an example of the second EA mechanism . The first EA mechanism 53A generates a base load BN by deformation of the torsion bar 7 provided between the spool 4 and the lock mechanism 6. As shown in FIG. The second EA mechanism 54A reduces the limit load LN by deformation or breakage of the shear pin 30 provided between the motor 12 and the spool 4 . The torsion bar 7 is an example of a first EA member, and the shear pin 30 is an example of a second EA member. The configuration of the retractor 1A will be described below with reference to FIGS. 4 to 8. FIG.

The retractor 1A includes a frame 2, a spool 4, a vehicle sensor 5, a lock mechanism 6, a torsion bar 7, a pretensioner 8 and a power transmission mechanism 21A.

The frame 2 is a housing that rotatably accommodates the spool 4 and forms the skeleton of the retractor 1A. The frame 2 has, for example, a pair of facing side portions 2b and 2c and a back portion 2a connecting the side portions 2b and 2c. A locking mechanism 6 is arranged on the outside of the side portion 2b (that is, on the opposite side of the side portion 2b to the spool 4 side). The pair of side portions 2b and 2c each have a circular (including substantially circular) opening.

The spool 4 is a winding member that is rotatably supported concentrically (including substantially concentrically) with the openings of the pair of side portions 2b and 2c of the frame 2 and that winds up the seat belt 104. As shown in FIG.

The vehicle sensor 5 is an example of a detection mechanism that detects a change in behavior of the vehicle (specifically, a rapid change in acceleration/deceleration or inclination of the vehicle caused by the change in behavior of the vehicle). The vehicle sensor 5 has, for example, a sphere that moves with vehicle deceleration that occurs in an emergency, and a locking pawl that is actuated by the movement of the sphere.

The lock mechanism 6 performs a lock operation to lock the rotation of the spool 4 in the seat belt 104 withdrawal direction. The lock mechanism 6 has a lock gear 14 and a locking base 17 . The lock gear 14 is fitted to the tip portion 7a of the torsion bar 7 projecting outward from the side surface portion 2b of the frame 2 so as to be relatively rotatable with respect to the torsion bar 7. As shown in FIG. The tip portion 7a may be a separate member such as a shaft that is axially connected to the torsion bar 7, or may be a part of the torsion bar 7 itself. The locking base 17 is rotatably supported by a second torque transmission portion 16, which will be described later, and holds the pawl so as to swing. The locking base 17 is an example of a locking member, rotates together with the spool 4 during normal operation, and prevents the rotation of the spool 4 in the seat belt 104 withdrawal direction during operation. Ratchet teeth 14 a are formed on the outer circumference of the lock gear 14 .

The lock gear 14 normally rotates together with the torsion bar 7 . On the other hand, in the above-described emergency, the ball of the vehicle sensor 5 is actuated and the locking pawl is engaged with the ratchet teeth 14a. This prevents (locks) the rotation of the lock gear 14 in the seat belt 104 withdrawal direction. When the rotation of the lock gear 14 is locked, relative rotation occurs between the locking base 17 and the lock gear 14, and the pawl provided on the locking base 17 rotates. engaged with the internal teeth 2ba. As a result, the rotation of the locking base 17 is stopped, and the rotation of the spool 4 in the direction in which the seat belt 104 is withdrawn is also prevented.

The torsion bar 7 is formed with a first torque transmission portion 15 that non-rotatably engages with the spool 4 and a second torque transmission portion 16 that non-rotatably engages with the locking base 17 . These transmission parts are provided at locations separated from each other in the axial direction. The first torque transmission portion 15 is an example of a first portion 55 (see FIG. 2) that engages with the spool 4 . The second torque transmission portion 16 is an example of a second portion 56 (see FIG. 2) locked by the lock mechanism 6 .

The pretensioner 8 has a rotating body 27 that rotates the spool 4 in the winding direction of the seat belt 104 when activated. Since a known configuration can be applied to the power generating section that rotates the rotating body 27, its illustration is omitted. The pretensioner 8 is actuated at the beginning of an emergency to generate reaction gas in the power generator, and the belt winding torque generated by this reaction gas is transmitted to the spool 4 via the rotating body 27 . As a result, the seat belt 104 is wound on the spool 4 by a predetermined amount at the initial stage of an emergency. The rotor 27 is connected to the end of the spool 4 so as to be rotatable together with the spool 4 .

The rotating body 27 rotates the spool 4 in the winding direction of the seat belt 104 when the pretensioner 8 is activated. The rotating body 27 is also called a paddle wheel. The rotor 27 is coaxially connected to the spool 4 . The projectile pushed by the gas generated by the gas generator of the power generation unit contacts the outer peripheral portion 27 a of the rotating body 27 to rotate the rotating body 27 in the winding direction of the seat belt 104 . As a result, the spool 4 also rotates in the winding direction of the seat belt 104 . That is, the seat belt 104 is wound around the spool 4 .

The power transmission mechanism 21A is an example of the power transmission mechanism 21 shown in FIG. The power transmission mechanism 21A includes a motor 12, a retainer 29, a first speed reduction mechanism 51A, a second EA mechanism 54A, a second speed reduction mechanism 52A and a clutch 25. The rotating body 27 may be one element of the power transmission mechanism 21A.

The motor 12 generates power to rotate the spool 4 . Motor 12 is fixed to retainer 29 .

The retainer 29 includes a through hole 29e through which the output shaft 12a of the motor 12 passes, a shaft 29b that rotatably holds the pair of connect gears 44 and 45, a boss 29a that rotatably holds the idle gear 26, and a rotating body. 27 and a holding hole 29c for rotatably holding it.

The first speed reduction mechanism 51A is an example of the first speed reduction mechanism 51 (see FIG. 2) and has a motor gear 20 and a connect gear 45. As shown in FIG. The connect gear 45 is a component shared by the first speed reduction mechanism 51A and the second EA mechanism 54A.

The motor gear 20 is attached to the output shaft 12a of the motor 12 so as to rotate integrally therewith. The motor gear 20 has external teeth 20a and a shaft hole 20b into which the output shaft 12a is inserted.

The connect gear 45 has external teeth 45a that are always meshed with the external teeth 20a of the motor gear 20, a shaft hole 45b into which the shaft 29b is inserted, and a shear pin 30 that extends in the thrust direction of the first speed reduction mechanism 51A (parallel to the axis of the connect gear 45). direction). A pin hole 45 c is formed in the end face of the connect gear 45 . The external teeth 45a have more teeth than the external teeth 20a. The connect gear 45 rotates around the shaft 29b.

The second EA mechanism 54A has a shear pin 30 which is an EA member and a pair of connect gears 44 and 45 interconnected via the shear pin 30 .

The shear pin 30 extends in the thrust direction of the first speed reduction mechanism 51A and the second speed reduction mechanism 52A. A pair of connect gears 44 and 45 are connected by a shear pin 30, and the connection is cut when the shear pin 30 is broken. The shear pin 30 is fixed to one or both of the pair of connect gears 44 and 45 . For example, the shear pin 30 having a male thread is screwed to one or both of the pair of connect gears 44 and 45 .

The connect gear 44 has external teeth 44a that are in constant mesh with the external teeth 26a of the idle gear 26, a shaft hole 44b into which the shaft 29b is inserted, and a shear pin 30 that extends in the thrust direction of the second speed reduction mechanism 52A (along the axis of the connect gear 44). and a pin hole 44c penetrating in the parallel direction). A pin hole 44 c is formed in the end face of the connect gear 44 . External teeth 44a have fewer teeth than external teeth 26a. The connect gear 44 rotates about the shaft 29b. The connect gear 44 has a smaller diameter than the connect gear 45 and faces the end surface of the connect gear 45 . The outer shape of the connect gear 44 is substantially disc-shaped.

The second speed reduction mechanism 52A is an example of the second speed reduction mechanism 52 (see FIG. 2) and has a connect gear 44, an idle gear 26 and a drive gear 23. The connect gear 44 is a component shared by the second EA mechanism 54A and the second reduction mechanism 52A, and the drive gear 23 is a component shared by the second reduction mechanism 52A and the clutch 25.

The idle gear 26 has external teeth 26a that always mesh with both the external teeth 44a of the connect gear 44 and the external teeth 23a of the drive gear 23, and a shaft hole 26b into which a boss 29a is inserted. The external teeth 26a have more teeth than the external teeth 44a. The idle gear 26 rotates around a boss 29a.

The drive gear 23 has external teeth 23a having a larger number of teeth than the external teeth 26a of the idle gear 26, and a shaft hole 23b in which the tip portion 7b of the torsion bar 7 is fitted so as to be relatively rotatable.

The clutch 25 is arranged coaxially with the rotation axis of the spool 4 (the torsion bar 7 in this embodiment), that is, positioned on the same axis as the rotation axis of the spool 4 .

The clutch 25 has a drive gear 23 , a clutch outer 24 and a clutch pawl 41 .

The drive gear 23 is rotatably supported by the tip portion 7b coaxial with the rotating shaft of the spool 4, and rotates as the output shaft 12a of the motor 12 rotates. The tip portion 7b is inserted into the shaft hole 23b of the drive gear 23 and the shaft hole 24b of the clutch outer 24. As shown in FIG. The drive gear 23 has an outer diameter larger than that of the idle gear 26 and has external teeth 23a. The external teeth 23a of the drive gear 23 are connected to the output shaft 12a of the motor 12 via the second speed reduction mechanism 52A, the second EA mechanism 54A and the first speed reduction mechanism 51A. The drive gear 23 is an example of a first rotating member.

The clutch outer 24 is rotatably supported coaxially with the drive gear 23 and directly or indirectly connected to the spool 4 . In this embodiment, the clutch outer 24 is integrally connected to the inner peripheral portion of the spool 4 via the rotating body 27 . The clutch outer 24 has a boss 24a connected to a shaft hole 27b of the rotor 27 so as to be rotatable together with the rotor 27, and a shaft hole 24b through which the tip portion 7b passes. The clutch outer 24 is an example of a second rotating member.

9 is a side view of the clutch 25. FIG. 10 is an exploded perspective view of the clutch 25. FIG. FIG. 11 is a diagram showing an off state (clutch pawl closed state) of the clutch 25 along the arrow BB (see FIG. 9). FIG. 12 is a view showing the ON operation of the clutch (clutch pawl open state) in the direction of arrows BB (see FIG. 9). Next, the configuration of the clutch 25 will be described in more detail with reference to FIGS. 9-12.

The clutch 25 includes a drive gear 23, a clutch outer 24 that is rotatably supported coaxially with the drive gear 23, a pair of clutch pawls 41 provided on the drive gear 23, and a pair of clutch pawls 41 that bias the pair of clutch pawls 41. and a clutch spring 42 .

An end face 23i of the drive gear 23 is formed with a pair of bosses 23e and 23h, a pair of mounting portions 23c and 23f, and a pair of stoppers 23d and 23g. Inside the outer peripheral wall 24c of the clutch outer 24, ratchet internal teeth 24d are formed.

The clutch pawl 41a is supported by the boss 23e so as to swing around the boss 23e along the end surface 23i. The clutch pawl 41b is supported by the boss 23h so as to swing around the boss 23h along the end surface 23i.

The clutch pawl 41a has a pushed portion 41ab formed on one side with respect to the boss 23e and a claw portion 41aa formed on the other side with respect to the boss 23e. The clutch pawl 41b has a pushed portion 41bb formed on one side with respect to the boss 23h and a claw portion 41ba formed on the other side with respect to the boss 23h.

The clutch spring 42a urges the pressed portion 41ab toward the ratchet inner tooth 24d and urges the pawl portion 41aa away from the ratchet inner tooth 24d. A biasing member disposed therebetween. The clutch spring 42a has one spring end attached to the attachment portion 23c and the other spring end that pushes the pressed portion 41ab in a direction approaching the ratchet internal teeth 24d. The stopper 23d limits the movement of the pressed portion 41ab in the direction toward the ratchet inner tooth 24d so that the pressed portion 41ab does not come into contact with the ratchet inner tooth 24d.

Similarly, the clutch spring 42b urges the pressed portion 41bb toward the ratchet inner tooth 24d and urges the pawl portion 41ba away from the ratchet inner tooth 24d. 41bb. The clutch spring 42b has one spring end attached to the attachment portion 23f and the other spring end that pushes the pressed portion 41bb in a direction approaching the ratchet internal teeth 24d. A stopper 23g restricts the movement of the pressed portion 41bb in the direction toward the ratchet inner tooth 24d so that the pressed portion 41bb does not come into contact with the ratchet inner tooth 24d.

Therefore, as shown in FIG. 11, when the drive gear 23 stops rotating, the clutch pawl 41a is held at a position where it does not engage with the ratchet internal teeth 24d of the clutch outer 24 due to the biasing force of the clutch spring 42a. be. That is, the pawl portion 41aa does not engage with the ratchet internal teeth 24d.

Similarly, as shown in FIG. 11, when the drive gear 23 stops rotating, the clutch pawl 41b is held at a position where it does not engage with the ratchet internal teeth 24d of the clutch outer 24 according to the biasing force of the clutch spring 42b. be done. That is, the pawl portion 41ba does not engage with the ratchet internal teeth 24d.

On the other hand, when the output shaft 12a of the motor 12 is rotating, the rotation of the motor gear 20 and the pair of connecting gears 44 and 45 causes the drive gear 23 to rotate about the shaft hole 24b. When the drive gear 23 rotates, centrifugal force acts on the clutch pawls 41a and 41b.

When the drive gear 23 rotates in the direction corresponding to the winding direction of the seat belt 104 due to the rotation of the output shaft 12a, the clutch pawl 41a moves due to its centrifugal force while resisting the biasing force of the clutch spring 42a. The clutch pawl 41a moved by the centrifugal force engages with the ratchet internal teeth 24d of the clutch outer 24 (see FIG. 12). That is, the pawl portion 41aa engages with the ratchet internal teeth 24d. Conversely, when the drive gear 23 rotates in the direction corresponding to the withdrawal direction of the seat belt 104 due to the rotation of the output shaft 12a, the clutch pawl 41a moves toward the ratchet internal teeth 24d due to the stopper 23d even if the centrifugal force acts thereon. movement is restricted. Therefore, the engagement between the clutch pawl 41a and the ratchet internal tooth 24d is prevented (see FIG. 11). That is, the pawl portion 41aa does not engage with the ratchet internal teeth 24d.

Similarly, the clutch pawl 41b engages with the ratchet internal teeth 24d when the drive gear 23 rotates in the direction corresponding to the winding direction of the seat belt 104 due to the rotation of the output shaft 12a (see FIG. 12). That is, the pawl portion 41ba engages with the ratchet internal teeth 24d. Conversely, the clutch pawl 41b does not engage with the ratchet internal teeth 24d when the drive gear 23 rotates in the direction corresponding to the withdrawal direction of the seat belt 104 due to the rotation of the output shaft 12a (see FIG. 11). That is, the pawl portion 41ba does not engage with the ratchet internal teeth 24d.

Therefore, when the drive gear 23 rotates in the direction corresponding to the winding direction of the seat belt 104 due to the rotation of the output shaft 12a, the pawls 41aa and 41ba of the clutch pawls 41a and 41b are engaged with the ratchet internal teeth 24d. state is maintained. In this engaged state, the rotational power of the output shaft 12a is applied to the motor gear 20, the connect gear 45, the second EA mechanism 54A, the connect gear 44, the idle gear 26, the drive gear 23, the pair of clutch pawls 41, and the clutch outer 24. transmitted along the route. The clutch outer 24 is connected to the inner peripheral side of the spool 4 via the rotating body 27 . Therefore, in such an engaged state, the rotational force of the output shaft 12a is transmitted to the spool 4, so that the seat belt 104 is wound around the spool 4. As shown in FIG.

On the other hand, when the drive gear 23 rotates in the direction corresponding to the withdrawal direction of the seat belt 104 due to the rotation of the output shaft 12a, the claws 41aa and 41ba of the clutch pawls 41a and 41b do not engage the ratchet internal teeth 24d. state is maintained. Further, when the rotation of the output shaft 12a is stopped, the rotation of the drive gear 23 is also stopped, so that the claw portions 41aa and 41ba of the clutch pawls 41a and 41b do not engage with the ratchet internal teeth 24d. be done. In these disengaged states, the rotational force of the rotating shaft of the spool 4 is transmitted through the rotating body 27 and the clutch outer 24 in order, but is not transmitted to the drive gear 23 . Therefore, in such a disengaged state, the rotational force of the rotating shaft of the spool 4 is not transmitted to the output shaft 12a. That is, transmission of torque from the rotation shaft of the spool 4 to the output shaft 12a is cut off.

Thus, the clutch 25 is a one-way clutch that blocks transmission of torque from the spool 4 to the motor 12 and transmits torque from the motor 12 to the spool 4 . Therefore, transmission of rotational force from the spool 4 to the motor 12 is interrupted by the clutch 25, so that the occupant 111 can smoothly withdraw the seat belt 104 from the retractor 1 or cause the retractor 1 to wind the seat belt 104 smoothly. Further, since the clutch 25 and the spool 4 are connected to each other via the rotating body 27, it is possible to prevent the rotational torque of the rotating body 27 of the pretensioner 8 from being transmitted to the motor 12 at the time of collision.

Also, in the event of a vehicle collision, the seat belt 104 is strongly wound around the spool 4 by the pretensioner 8, the motor 12, and the like. After that, the seat belt 104 is pulled out by the forward movement of the occupant, so that the lock mechanism 6 is operated, the torsion bar 7 is twisted, and the EA load is generated. The retractor 1A mounts a shear pin 30 that causes shear failure when a load greater than or equal to a set load is input between a pair of connecting gears 44 and 45 that are stacked.

The pair of connect gears 44 and 45 are connected by the shear pin 30 during normal operation. Therefore, the pair of connect gears 44 and 45 rotate integrally around the shaft 29b, and the torque generated by the motor 12 is transmitted to the spool 4 via each gear of the reduction mechanism. The assist load AN transmitted from the motor 12 is applied to at least one torsion bar 7, and acts on the vehicle occupant as part of the EA load.

However, during control of the motor 12 (during rotation of the output shaft 12a), if a load exceeding a preset load occurs between the pair of connect gears 44 and 45, the shear pin 30 is sheared and broken. The connection between gears 44, 45 is broken. As a result, the assist load AN generated by the motor 12 is no longer transmitted to the spool 4 , thereby preventing an excessive load from acting on the seat belt 104 . Further, even if the assist load AN is no longer transmitted to the spool 4, at least the base load BN is ensured, so the occupant's energy can be absorbed and mitigated by the base load BN.

FIG. 13 is a diagram showing a cross section of the seat belt retractor in the second embodiment, taken along line AA (see FIG. 6). FIG. 6 is a cross section of the seatbelt retractor in the first embodiment, and is used for the description of the seatbelt retractor in the second embodiment. FIG. 14 is an exploded perspective view of the seat belt retractor in the second embodiment. The second embodiment differs from the first embodiment in the second EA mechanism. The configuration of the retractor 1B according to the second embodiment will be described below with reference to FIGS. The description of the same configuration and effects as those of the retractor 1A in the first embodiment will be omitted or simplified by citing the above description.

A retractor 1B shown in FIGS. 13 and 14 is an example of a seat belt retractor, and is a specific example of the retractor 1 shown in FIG. The retractor 1B includes a second EA mechanism 54B, which is an example of the second EA mechanism 54. As shown in FIG. The second EA mechanism 54B reduces the limit load LN by deformation or breakage of the shear pin 31 provided between the motor 12 and the spool 4 . The shear pin 31 is an example of a second EA member.

The retractor 1B includes a frame 2, a spool 4, a vehicle sensor 5, a lock mechanism 6, a torsion bar 7, a pretensioner 8 and a power transmission mechanism 21B.

The power transmission mechanism 21B is an example of the power transmission mechanism 21 shown in FIG. The power transmission mechanism 21B includes a motor 12, a retainer 29, a first speed reduction mechanism 51A, a second EA mechanism 54B, a second speed reduction mechanism 52A and a clutch 25. The rotating body 27 may be one element of the power transmission mechanism 21B.

The first speed reduction mechanism 51A is an example of the first speed reduction mechanism 51 (see FIG. 2) and has a motor gear 20 and a connect gear 45. As shown in FIG. The connect gear 45 is a component shared by the first speed reduction mechanism 51A and the second EA mechanism 54B.

FIG. 15 is a perspective view of a connect gear mounted on the retractor 1B according to the second embodiment. The connect gear 45 has external teeth 45a that are always meshed with the external teeth 20a of the motor gear 20, a shaft hole 45b into which the shaft 29b is inserted, and a radial direction of the first speed reduction mechanism 51A (a direction perpendicular to the axis of the connect gear 45). and a recessed groove 45g. The groove 45g is formed in the inner peripheral portion 45d of the recessed portion 45e of the connect gear 45, and holds the radially outer end portion of the shear pin 31. As shown in FIG.

14, the second EA mechanism 54B has a shear pin 31, which is an EA member, and a pair of connect gears 44, 45 interconnected via the shear pin 31. As shown in FIG.

The shear pin 31 extends in the radial direction of the first speed reduction mechanism 51A and the second speed reduction mechanism 52A. The pair of connect gears 44 and 45 are connected by the shear pin 31, and the connection is cut by breaking the shear pin 31 at the predetermined breaking portion 31c. The shear pin 31 is fixed to one or both of the pair of connect gears 44 and 45 .

The connect gear 44 has external teeth 44a that are always meshed with the external teeth 26a of the idle gear 26, a shaft hole 44b into which the shaft 29b is inserted, and a radial direction of the second speed reduction mechanism 52A (a direction perpendicular to the axis of the connect gear 44). ) and recessed grooves 44d. The groove 44 d is formed in the end face of the connect gear 44 and holds the radial inner end of the shear pin 31 . The connect gear 44 has a diameter smaller than that of the connect gear 45 , faces the end surface of the connect gear 45 , and fits into a recess 45 e (see FIG. 15 ) of the connect gear 45 . The outer shape of the connect gear 44 is substantially disc-shaped.

In this manner, the retractor 1B mounts the shear pin 31 that causes shear failure when a load greater than or equal to the set load is input between the pair of connecting gears 44 and 45 that are superimposed. During normal operation, the pair of connect gears 44 and 45 are connected by the share pin 31 . Therefore, the pair of connect gears 44 and 45 rotate together around the shaft 29b. During control of the motor 12 (during rotation of the output shaft 12a), if a load greater than a preset load is generated between the pair of connect gears 44 and 45, the shear pin 31 is sheared and fractured at the planned fracture portion 31c. The connection between the pair of connect gears 44, 45 is cut. As a result, the assist load AN generated by the motor 12 is no longer transmitted to the spool 4 , thereby preventing an excessive load from acting on the seat belt 104 . Further, even if the assist load AN is no longer transmitted to the spool 4, at least the base load BN is ensured, so the occupant's energy can be absorbed and mitigated by the base load BN.

FIG. 16 is a diagram showing a cross-sectional view of the seat belt retractor in the third embodiment taken along line AA (see FIG. 6). FIG. 6 is a cross section of the seatbelt retractor in the first embodiment, and is used for the description of the seatbelt retractor in the third embodiment. FIG. 17 is an exploded perspective view of the seat belt retractor in the third embodiment. The third embodiment differs from the first embodiment in the second EA mechanism. The configuration of the retractor 1C according to the third embodiment will be described below with reference to FIGS. The description of the same configuration and effects as those of the retractor 1A in the first embodiment will be omitted or simplified by citing the above description.

A retractor 1C shown in FIGS. 16 and 17 is an example of a seat belt retractor, and is a specific example of the retractor 1 shown in FIG. The retractor 1C includes a second EA mechanism 54C, which is an example of the second EA mechanism 54. As shown in FIG. The second EA mechanism 54C reduces the limit load LN by deforming or breaking a shear pin 45f (see FIG. 18) provided between the motor 12 and the spool 4. The shear pin 45f is an example of a second EA member.

FIG. 18 is a perspective view of a connect gear mounted on the retractor 1C according to the third embodiment. The connect gear 45 has a shear pin 45f protruding in the thrust direction of the connect gear 45. As shown in FIG. The share pin 45f is a portion integrated with the connect gear 45 of the first speed reduction mechanism 51A, and is formed in the recess 45e of the connect gear 45. As shown in FIG.

In FIG. 17, the second EA mechanism 54C has a share pin 45f (see FIG. 18), which is an EA member, and a pair of connect gears 44 and 45 interconnected via the share pin 45f. The connect gear 44 has a pin hole 44e through which the share pin 45f penetrates in the thrust direction of the second speed reduction mechanism 52A (the direction parallel to the axis of the connect gear 44). A pin hole 44 e is formed in the end face of the connect gear 44 .

Therefore, as in the above embodiment, the breakage of the shear pin 45f cuts the connection between the pair of connect gears 44, 45, preventing an excessive load from acting on the seatbelt 104. FIG. A share pin projecting in the thrust direction of the connect gear 44 may be formed integrally with the connect gear 45 , and a pin hole through which the share pin penetrates the connect gear 45 in the thrust direction may be formed in the connect gear 45 .

FIG. 19 is an exploded perspective view of the seat belt retractor in the fourth embodiment. The fourth embodiment differs from the second embodiment in the second EA mechanism. The configuration of the retractor 1D according to the fourth embodiment will be described below with reference to FIG. The description of the same configuration and effects as those of the retractor 1D in the fourth embodiment will be omitted or simplified by citing the above description.

A retractor 1D shown in FIG. 19 is an example of a seat belt retractor, and is a specific example of the retractor 1 shown in FIG. The retractor 1D includes a second EA mechanism 54D, which is an example of the second EA mechanism 54. As shown in FIG. The second EA mechanism 54D reduces the limit load LN by deformation or breakage of the shear pin 44f provided between the motor 12 and the spool 4. The shear pin 44f is an example of a second EA member.

The connect gear 44 has a shear pin 44 f protruding in the radial direction of the connect gear 44 . The share pin 44f is a portion integrated with the connect gear 44 of the second speed reduction mechanism 52A, and is formed on the outer peripheral surface of the connect gear 44. As shown in FIG.

The second EA mechanism 54D has a share pin 44f, which is an EA member, and a pair of connect gears 44, 45 connected to each other via the share pin 45f. The connect gear 45 has a groove 45g (see FIG. 15) in which the share pin 44f is recessed in the radial direction of the first speed reduction mechanism 51A (direction perpendicular to the axis of the connect gear 45). The groove 45g holds the radial outer end of the shear pin 44f.

Therefore, as in the above embodiment, the breakage of the shear pin 44f cuts off the connection between the pair of connect gears 44, 45, preventing an excessive load from acting on the seatbelt 104. FIG. In addition, a share pin protruding inward from the inner peripheral portion 45d in the radial direction of the connect gear 45 is formed integrally with the connect gear 45, and a groove recessed in the radial direction of the connect gear 44 is formed on the outer peripheral surface of the connect gear 45, The shear pin may be held in the groove.

Although the seat belt retractor and the seat belt device have been described above with reference to the embodiments, the present invention is not limited to the above embodiments. Various modifications and improvements such as combination or replacement with part or all of other embodiments are possible within the scope of the present invention.

For example, the number of clutch pawls is not limited to two, and may be one or three or more. Further, the number of gears included in each of the first speed reduction mechanism 51 and the second speed reduction mechanism 52 is not limited to two, and may be one or three or more.

Further, the second EA mechanism 54 may set the second limit load N2 or the upper limit load Lb by deformation or breakage (dividing) of a member (for example, torsion bar, plate, etc.) other than the shear pin.

1, 1A, 1B Retractor 2 Frame 4 Spool 5 Vehicle sensor 6 Lock mechanism 7 Torsion bar 8 Pretensioner 10 Control unit 12 Motor 14 Lock gear 17 Locking base 20 Motor gears 21, 21A, 21B Power transmission mechanism 23 Drive gear 24 Clutch outer 25 Clutch 26 Idle gear 27 Rotating body 29 Retainers 30, 31 Share pin 41 Clutch pawls 44, 45 Connect gears 44f, 45f Share pins 51, 51A First speed reduction mechanisms 52, 52A Second speed reduction mechanisms 53, 53A First EA mechanism 54 , 54A, 54B, 54C, 54D Second EA mechanism 55 First part 56 Second part

Claims (22)

a spool for winding the seat belt;
a locking mechanism that allows rotation of the spool when not in operation and prevents rotation of the spool in the seat belt withdrawal direction when in operation;
a first energy absorption mechanism deformed by rotation of the spool in the pull-out direction and rotation prevention by the lock mechanism;
a power transmission mechanism that adds a second load generated by power of a motor to a first load generated by deformation of the first energy absorption mechanism;
a second energy absorption mechanism that reduces the limit load, which is increased by adding the second load to the first load, by its own deformation ,
The power transmission mechanism has a clutch that blocks transmission of force from the spool to the motor and allows transmission of force from the motor to the spool,
The seat belt retractor , wherein the clutch is connected to the output shaft of the motor via the second energy absorption mechanism . 2. The seat belt retractor according to claim 1, wherein said limit load lowers said first load to a lower limit by breaking said second energy absorbing mechanism. 3. The seat belt retractor according to claim 1 or 2, wherein said limit load is reduced by disconnection between said motor and said spool by said second energy absorbing mechanism. 4. The seat belt retractor according to claim 3, wherein said second energy absorbing mechanism cuts the connection between said motor and said spool when said limit load or said second load reaches a set value. 5. A seat belt retractor according to claim 3 or 4, wherein the connection between the motor and the spool is severed by breaking the second energy absorbing mechanism. The seat belt retractor according to claim 2 or 5, wherein the breakage of the second energy absorption mechanism is shear pin shear. 7. The seat belt retractor according to any one of claims 1 to 6, wherein said motor and said spool are interconnected via said second energy absorbing mechanism. The power transmission mechanism has a reduction mechanism that reduces and transmits the rotation of the output shaft of the motor,
8. The seat belt retractor according to claim 7, wherein said speed reduction mechanism has a first speed reduction mechanism and a second speed reduction mechanism interconnected via said second energy absorption mechanism. 9. The seat belt retractor according to claim 8, wherein said second energy absorbing mechanism and said spool are connected via said second reduction mechanism. The second energy absorption mechanism has a shear pin extending in the thrust direction of the first speed reduction mechanism and the second speed reduction mechanism,
The seat belt retractor according to claim 8 or 9, wherein said first speed reduction mechanism and said second speed reduction mechanism are connected to each other via said share pin. The second energy absorption mechanism has a shear pin extending in the radial direction of the first speed reduction mechanism and the second speed reduction mechanism,
The seat belt retractor according to claim 8 or 9, wherein said first speed reduction mechanism and said second speed reduction mechanism are connected to each other via said share pin. The seat belt retractor according to claim 10 or 11, wherein the shear pin is integrated with the first speed reduction mechanism or the second speed reduction mechanism. 7. The seat belt retractor according to claim 6 , wherein said second energy absorbing mechanism has a pair of connecting gears interconnected via said shear pin . The clutch blocks transmission of force from the spool to the output shaft when the output shaft of the motor stops rotating, and transmits force from the output shaft to the spool when the output shaft is rotating. 14. A seat belt retractor according to any one of claims 1 to 13 , allowing transmission of a force of . The clutch is
a first rotating member connected to the output shaft via the second energy absorption mechanism and rotating according to the rotation of the output shaft;
a second rotating member coaxially rotatably supported with the first rotating member and directly or indirectly coupled to the spool;
a clutch pawl provided on the first rotating member;
The clutch pawl is moved by a centrifugal force generated by the rotation of the first rotating member to engage with the second rotating member, and the second rotating member is engaged with the second rotating member while the first rotating member is not rotating. 15. The seat belt retractor of claim 14, which does not engage a rotating member. The clutch pawl moves by the centrifugal force while resisting the biasing force of the biasing member and engages with the second rotating member. 16. The seat belt retractor of claim 15, wherein the seat belt retractor is held in a position out of engagement with the second rotating member according to a force. 17. The seat belt retractor according to claim 15 or 16, wherein said clutch pawl is rockably supported by an end surface of said first rotating member and engages with internal teeth of said second rotating member by said centrifugal force. . A pretensioner having a rotating body that rotates the spool in the winding direction of the seat belt when actuated,
18. The seat belt retractor according to any one of claims 13 to 17, wherein said clutch and said spool are interconnected via said rotating body. the first energy absorbing mechanism has a first portion that engages the spool and a second portion that is locked by the locking mechanism;
The seat belt retractor according to any one of claims 1 to 18, wherein the power transmission mechanism transmits the second load to the first portion side. 20. The seat according to any one of claims 1 to 19, wherein said first energy absorbing mechanism generates said first load by deformation of a torsion bar provided between said spool and said locking mechanism. belt retractor. The seat belt retractor according to any one of claims 1 to 20, comprising a controller that adjusts the second load by controlling the motor. A seatbelt device comprising: the seatbelt retractor according to any one of claims 1 to 21; the seatbelt; a tongue attached to the seatbelt; and a buckle to which the tongue is detachably engaged. .

Images