JP2020172192A - Seat belt retractor and seat belt device - Google Patents

Abstract

To provide a seat belt retractor which can prevent an excessive load from acting on a seat belt.SOLUTION: A seat belt retractor includes: a spool which takes up a seat belt; a lock mechanism which allows rotation of the spool during non-operation time and prevents the rotation of the spool in a drawing direction of the seat belt during operation time; a first energy absorption mechanism which is deformed by the rotation of the spool in the drawing direction and prevention of the rotation by the lock mechanism; a power transmission mechanism which adds a second load generated by a motor and a speed reduction mechanism to a first load generated by deformation of the first energy absorption mechanism; and a second energy absorption mechanism which limits increase of a limit load generated by adding the second load to the first load by its deformation.SELECTED DRAWING: Figure 2

Description

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

A seatbelt device installed in a vehicle such as an automobile is used to restrain an occupant with a seatbelt in an emergency (for example, when a large vehicle deceleration acts on the vehicle in a collision while the seatbelt is fastened). Prevent the occupant from jumping out of the seat.

Such a seatbelt device is provided with a seatbelt retractor that winds up the seatbelt so that it can be pulled out. In this seatbelt retractor, the seatbelt is wound on the spool when it is not fastened, but is pulled out and fastened to the occupant when it is fastened. Then, in an emergency as described above, the locking means of the seatbelt retractor is activated to prevent the spool from rotating in the belt withdrawal direction, so that the seatbelt is prevented from being pulled out, so that the occupant is restrained by the seatbelt in an emergency. Ru.

When the occupant is restrained by the seat belt in an emergency such as a vehicle collision, a large vehicle deceleration occurs, so that the occupant tries to move forward due to a large inertia. Therefore, a large load is applied to the seat belt, and the occupant receives a large force from the seat belt. This force is not a problem for the occupants, but it should be limited if possible.

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

Japanese Unexamined Patent Publication No. 2001-270423

However, in the conventional technique, if the load generated by the motor becomes excessive for some reason such as a failure, an unintended excessive load may act on the seat belt.

Therefore, the present disclosure provides a seatbelt retractor and a seatbelt device capable of preventing an excessive load from acting on the seatbelt.

This disclosure is
The spool that winds up the seat belt and
A lock mechanism that allows the spool to rotate when not operating and prevents the spool from rotating in the pull-out direction of the seat belt when operating.
A first energy absorption mechanism that is deformed by the rotation of the spool in the pull-out direction and the rotation prevention by the lock mechanism, and
A power transmission mechanism that adds a second load generated by the motor and the deceleration mechanism to the first load generated by the deformation of the first energy absorption mechanism.
Provided is a seatbelt retractor including a second energy absorbing mechanism that limits an increase in a limiting load generated by adding the second load to the first load by its own deformation. 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 capable of preventing an excessive load from acting on the seatbelt.

It is a figure which illustrates the structure of the seat belt apparatus in one Embodiment. It is a block diagram which illustrates the structure of the seat belt retractor in one Embodiment. It is a figure which illustrates the behavior of the limit load with respect to the stroke of a spool. It is a front view of the seat belt retractor in the 1st Embodiment. It is a right side view of the seatbelt retractor in the 1st Embodiment. It is a left side view of the seatbelt retractor in the 1st Embodiment. It is a figure which shows the cut surface of the seatbelt retractor in 1st Embodiment by arrow view AA (see FIG. 6). It is an exploded perspective view of the seat belt retractor in the 1st Embodiment. It is a side view of a clutch. It is an exploded perspective view of a clutch. It is a figure which shows the disengaged state of a clutch (the closed state of a clutch Paul) by the arrow BB (see FIG. 9). It is a figure which shows the on-operation of the clutch (the clutch Paul open state) by the arrow BB (see FIG. 9). It is a front view of the seat belt retractor in the 2nd Embodiment. It is a right side view of the seatbelt retractor in the 2nd Embodiment. It is a left side view of the seatbelt retractor in the 2nd Embodiment. It is a figure which shows the cut surface of the seatbelt retractor in the 2nd Embodiment by arrow CC (see FIG. 15). It is an exploded perspective view of the seat belt retractor in the 2nd Embodiment. It is a perspective view of the 1st plate holding gear. It is a perspective view of the 2nd plate holding gear. It is a figure which shows the state before the operation of the EA plate. It is a figure which shows the operating state of the EA plate.

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

FIG. 1 is a diagram illustrating a configuration of a seatbelt device according to an embodiment according to the present disclosure. The seatbelt device 101 shown in FIG. 1 is an example of a seatbelt 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 108.

The seat belt 104 is an example of a seat belt that restrains an occupant 111 sitting on the seat 102 of the vehicle, and is a band-shaped member that is retractably wound around the retractor 103. Seat belts are also called webbing. The belt anchor 105 at the tip of the seat belt 104 is fixed to the seat 102 or the vehicle body in the vicinity of the seat 102.

The retractor 103 is an example of a seatbelt winder that enables the seatbelt 104 to be wound up or pulled out. The retractor 103 restricts the seatbelt 104 from being pulled out from the retractor 103 when an acceleration / deceleration or a vehicle angle equal to or higher than a predetermined value is detected, such as when a vehicle collides. The retractor 103 is fixed to the seat 102 or the vehicle body in the vicinity of the seat 102. The retractor 103 is an example of a seatbelt retractor.

The retractor 103 has a function of winding the seat belt 104 on the 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 onto a spool, and applies pretension to the seatbelt 104 to give the seatbelt 104 a pretension. Quickly restrain the occupants by. Further, the retractor 103 operates the motor 103a when the connection between the tongue 107 and the buckle 108 is released, and winds the seatbelt 104 with a spool, for example. The retractor 103, for example, operates the motor 103a to adjust the tension of the seatbelt 104 according to the driving situation (vehicle condition), so that the occupant is restrained by the seatbelt 104 and the seatbelt 104 is comfortable to wear. Improve each sex.

The state of the vehicle is, for example, whether or not the seatbelt 104 is pulled out, whether or not the occupant 111 is present, the running speed of the vehicle, the acceleration of the vehicle, the steering operation, the accelerator operation, the brake operation, the operation of the buckle 108, the door operation, and the operation by the occupant. It refers to a state that represents the operation input of a possible in-vehicle selection switch.

The shoulder anchor 106 is an example of a belt insertion tool through which the seat belt 104 is inserted, and is a member that guides the seat belt 104 pulled out from the retractor 103 toward the shoulder portion of the occupant 111. The shoulder anchor 106 is fixed to the seat 102 or the vehicle body in the vicinity of the seat 102.

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

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

With the tongue 107 connected to the buckle 108, the portion of the seatbelt 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 seatbelt 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 the seatbelt retractor according to the embodiment of the present disclosure. The retractor 1 and the motor 12 shown in FIG. 2 correspond to the retractor 103 and the motor 103a shown in FIG. 1, respectively. The retractor 1 is a seatbelt retractor including 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 up the seat belt 104 so as to be able to be pulled out.

The lock mechanism 6 allows the spool 4 to rotate when it is not operating, and prevents the spool 4 from rotating in the pull-out direction of the seat belt 104 when it is operating. The lock mechanism 6 locks the first EA mechanism 53 during operation to prevent the spool 4 from rotating in the pull-out direction of the seat belt 104.

The first EA mechanism 53 is deformed by the rotation of the spool 4 in the pull-out direction of the seat belt 104 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 relax the energy of the occupant.

For example, in an emergency such as a vehicle collision, the seatbelt 104 is strongly wound around the spool 4 by rotating the spool 4 in the belt winding direction by operating at least one of the pretensioner 8 and the motor 12. After that, the seat belt 104 tries to be pulled out from the spool 4 as the occupant moves 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 pull-out direction is prevented. However, since the spool 4 tends to rotate in the belt pull-out direction, the first EA mechanism 53 is deformed by the rotation of the spool 4 in the pull-out direction of the seat belt 104 and the rotation prevention by the lock mechanism 6. Deformation of the first EA mechanism 53 limits the load acting on the seatbelt 104 drawn from the spool 4. That is, the energy of the occupant is absorbed and relaxed by the deformation of the first EA mechanism 53.

The power transmission mechanism 21 has a first load (hereinafter, also referred to as a base load BN) generated by deformation of the first EA mechanism 53, and a second load (hereinafter, assist load AN) generated by the motor 12 and the reduction mechanism. Also called) is added. The number of reduction mechanisms for decelerating and transmitting the rotation of the output shaft of the motor 12 may be one or a plurality. FIG. 2 shows a first deceleration mechanism 51 and a second deceleration mechanism 52. By adding the assist load AN to the base load BN, a limit load (hereinafter, also referred to as a limit load LN) is generated. The retractor 1 limits the load acting on the seatbelt 104 with the limiting load LN thus generated.

The second EA mechanism 54 limits the increase in the limiting load LN generated by adding the assist load AN to the base load BN by its own deformation. Therefore, even if the assist load AN generated by the motor 12 and the reduction mechanism becomes excessive for some reason such as a failure, the increase in the limiting load LN is limited by the deformation of the second EA mechanism 54. 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 to absorb and relax the energy of the occupant.

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

As shown in FIG. 3, the power transmission mechanism 21 sets the limit load LN by adding the assist load AN generated by the motor 12 and the deceleration mechanism to the base load BN generated by the deformation of the first EA mechanism 53. Generate. The limit load LN is substantially equal to the sum of the base load BN and the assist load AN.

When 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 the sum of 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 limiting load N1 is the maximum load that can be generated by the deformation of the first EA mechanism 53, and the second limiting load N2 can be generated by the deformation of the second EA mechanism 54. Maximum load. On the other hand, even if the limit load LN becomes excessive for some reason, it is limited so as not to exceed the upper limit load Lb as shown in the waveform c, so that the excessive load is prevented from acting on the seat belt 104. it can.

Further, even if the assist load AN cannot be added to the base load BN due to some abnormality due to a vehicle collision or the like (for example, a failure of the power transmission mechanism 21), the limit load LN is applied to the first EA mechanism 53 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 seatbelt 104 can be limited by the first limiting load N1 by the first EA mechanism 53, an excessive load acts on the seatbelt 104 even in an abnormal case where the assist load AN cannot be applied. 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 the range of the upper limit load Lb or less.

For example, the control unit 10 can adjust the rising speed of the limit load LN by adjusting the rising speed of the assist load AN by controlling the motor 12, as shown in the waveforms d and e of FIG. The waveform d indicates a case where the motor 12 is controlled so that the rising speed of the assist load AN becomes faster, and the waveform e indicates a case where the motor 12 is controlled so that the rising speed of the assist load AN becomes slower. Shown.

Further, for example, the control unit 10 may increase or decrease the positive assist load AN applied to the base load BN by controlling the motor 12. As a result, as shown in the waveforms f, g, and h of 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 a negative assist load AN is applied 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 increasing or decreasing the negative assist load AN applied to the base load BN by controlling the motor 12.

In this way, the control unit 10 can generate a flexible limit load LN within the range of the upper limit load Lb or less 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 occupant.

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

The motor 12 and the spool 4 are preferably connected to each other 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 that the magnitude of the assist load AN is accurately limited to the second limit load N2 or less by the second EA mechanism 54. it can.

In the configuration shown in FIG. 2, the deceleration mechanism that decelerates and transmits the rotation of the rotation shaft of the motor 12 is a first deceleration mechanism 51 and a second deceleration mechanism that are interconnected via a second EA mechanism 54. It has 52 and. That is, the second EA mechanism 54 is inserted and arranged in the power transmission path between the first deceleration mechanism 51 and the second deceleration mechanism 52. By connecting the second EA mechanism 54 and the spool 4 via the second deceleration mechanism 52, the second EA mechanism 54 provides the second EA mechanism 54 as compared with the form in which the second EA mechanism 54 and the spool 4 are connected without the second deceleration mechanism 52. Since the limit load N2 of 2 can be set small, the size of the second EA mechanism 54 can be reduced.

For example, consider the case where the upper limit load Lb is set to 4 kN (kilonewton). Assuming that the first limiting load N1 by the first EA mechanism 53 is 1 kN, in the form of connecting without passing through the second deceleration mechanism 52, the second limited load N2 by the second EA mechanism 54 is 3 kN ( = It is necessary to set Lb-N1). On the other hand, in the form of connecting via the second reduction mechanism 52, when the reduction ratio R of the second reduction mechanism 52 is 2, the second limit load N2 by the second EA mechanism 54 is set to 1. It may be set to .5 kN (= (Lb-N1) / R). Therefore, the size of the second EA mechanism 54 can be reduced in the form of connecting via the second deceleration mechanism 52 as compared with the form of connecting through the second deceleration mechanism 52. For example, when the second EA mechanism 54 generates the second limiting load N2 due to the deformation of the torsion bar, the torsion bar can be thinned, so that the second EA mechanism 54 is laid out in the retractor 1. Becomes easier.

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

Further, the power transmission mechanism 21 preferably has a clutch 25 that blocks the transmission of force from the spool 4 to the motor 12 and allows the transmission of force from the motor 12 to the spool 4. By providing the clutch 25 that cuts off the transmission of the force from the spool 4 to the motor 12, for example, it is possible to prevent the strong winding torque of the seat belt 104 by the pretensioner 8 at the time of collision from being transmitted to the motor 12. Further, when the rotation 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 winds the seat belt 104 around the retractor 1, the load of the motor 12 is reduced to the seat. It is transmitted to the occupant who operates the belt 104. As a result, the occupant cannot smoothly pull out or wind up the seat belt 104, which may cause discomfort to the occupant. On the other hand, the clutch 25 is a one-way clutch that blocks the transmission of the rotational force from the spool 4 to the motor 12 and transmits the rotational force from the motor 12 to the spool 4. Therefore, since the transmission of the rotational force from the spool 4 to the motor 12 is interrupted by the clutch 25, the occupant can smoothly pull out the seat belt 104 from the retractor 1 or wind it around the retractor 1.

The clutch 25 cuts off the transmission of force from the spool 4 to the output shaft 12a when the rotation of the output shaft 12a of the motor 12 is stopped, and the clutch 25 cuts off the transmission of the force from the output shaft 12a to the spool 4 when the output shaft 12a is rotating. Allows the transmission of force to. As a result, the control unit 10 operates the motor 12 to rotate the output shaft 12a, so that the clutch 25 can be turned on (the transmission of force from the output shaft 12a to the spool 4 can be allowed). On the other hand, the clutch 25 can be disengaged by stopping the motor 12 and stopping the rotation of the output shaft 12a by the control unit 10 (the transmission of the 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 embodiment shown in FIG. 2, the first EA mechanism 53 has a first portion 55 that engages with 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 side of the first portion 55. 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 seatbelt retractor according to the first embodiment. FIG. 5 is a right side view of the seatbelt retractor according to the first embodiment. FIG. 6 is a left side view of the seatbelt retractor according to the first embodiment. FIG. 7 is a diagram showing the cut surface of the seatbelt retractor in the first embodiment as seen by arrows AA (see FIG. 6). FIG. 8 is an exploded perspective view of the seatbelt retractor according to the first embodiment.

The retractor 1A shown in FIGS. 4 to 8 is an example of a seatbelt retractor, and is 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 54. The first EA mechanism 53A generates a base load BN by deforming the torsion bar 7 provided between the spool 4 and the lock mechanism 6. The second EA mechanism 54A limits the increase in the limiting load LN by deforming the torsion bar 30 provided between the motor 12 and the spool 4. The torsion bar 7 is an example of a first EA member, and the torsion bar 30 is an example of a second EA member. Hereinafter, the configuration of the retractor 1A will be described with reference to FIGS. 4 to 8.

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 side surface portions 2b and 2c facing each other and a back surface portion 2a connecting the side surface portions 2b and 2c. The lock mechanism 6 is arranged on the outside of the side surface portion 2b (that is, the side opposite to the side of the spool 4 with respect to the side surface portion 2b). Each of the pair of side surface portions 2b and 2c has a circular (including substantially circular) opening.

The spool 4 is a take-up member that is concentrically (including substantially concentric) and rotatably supported with the openings of the pair of side surface portions 2b and 2c of the frame 2 and winds up the seat belt 104.

The vehicle sensor 5 is an example of a detection mechanism that detects a change in the behavior of the vehicle (specifically, a sudden change in acceleration / deceleration or tilt of the vehicle caused by the change in the behavior of the vehicle). The vehicle sensor 5 has, for example, a sphere that moves at the vehicle deceleration that occurs in an emergency and a locking claw that operates by the movement of the sphere.

The lock mechanism 6 performs a locking operation that locks the rotation of the spool 4 in the pull-out direction of the seat belt 104. The lock mechanism 6 includes a lock gear 14 and a locking base 17. The lock gear 14 is fitted in a tip portion 7a of the torsion bar 7 protruding outward from the side surface portion 2b of the frame 2 so as to be rotatable relative to the torsion bar 7. The tip portion 7a may be a separate member such as a shaft connected to the torsion bar 7 in the axial direction, or may be a part of the torsion bar 7 itself. The locking base 17 is integrally rotatably supported by a second torque transmission unit 16 described later, and holds the poul swingably. The locking base 17 is an example of a locking member, which normally rotates with the spool 4 and prevents the spool 4 from rotating in the pull-out direction of the seat belt 104 during operation. Ratchet teeth 14a are formed on the outer periphery of the lock gear 14.

The lock gear 14 normally rotates integrally with the torsion bar 7. On the other hand, in the above-mentioned emergency, the sphere of the vehicle sensor 5 operates and the locking claw engages with the ratchet tooth 14a. As a result, the rotation of the lock gear 14 in the pull-out direction of the seat belt 104 is blocked (locked). When the rotation of the lock gear 14 is locked, a relative rotation occurs between the locking base 17 and the lock gear 14, the powl provided on the locking base 17 rotates, and the rotated poul is provided on the side surface portion 2b. Engage with the internal tooth 2ba. As a result, the rotation of the locking base 17 is stopped, and the rotation of the spool 4 in the pull-out direction of the seat belt 104 is also prevented.

The torsion bar 7 is formed with a first torque transmission unit 15 that engages with the spool 4 in a relative non-rotatable manner and a second torque transmission unit 16 that engages with a locking base 17 in a relative non-rotatable manner. These transmission portions are provided at locations separated from each other in the axial direction. The first torque transmission unit 15 is an example of a first portion 55 (see FIG. 2) that engages with the spool 4. The second torque transmission unit 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 during operation. Since a known configuration can be applied to the power generating unit that rotates the rotating body 27, the illustration thereof will be omitted. The pretensioner 8 operates at the initial stage of an emergency to generate a reaction gas at the power generation unit, and transmits the belt winding torque generated by the reaction gas to the spool 4 via the rotating body 27. As a result, in the initial stage of an emergency, the seat belt 104 is wound around the spool 4 by a predetermined amount. The rotating body 27 is connected to the end of the spool 4 so as to be rotatable integrally 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 operated. The rotating body 27 is also referred to as a paddle wheel. The rotating body 27 is coaxially connected to the spool 4. The ejector pushed by the gas generated by the gas generator of the power generating unit contacts the outer peripheral portion 27a 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 28, a first reduction mechanism 51A, a second EA mechanism 54A, a retainer 29, a second reduction mechanism 52A, and a clutch 25. The rotating body 27 may be an element of the power transmission mechanism 21A.

The motor 12 generates power to rotate the spool 4. The motor 12 is fixed to the retainer 28.

The retainer 28 has a through hole 28a through which the output shaft 12a of the motor 12 penetrates, and a holding hole 28b that rotatably holds the first tip portion 30a of the torsion bar 30.

The first reduction mechanism 51A is an example of the first reduction mechanism 51 (see FIG. 2), and has a motor gear 20 and a connect gear 22.

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

The connect gear 22 has an outer tooth 22a that constantly meshes with the outer tooth 20a of the motor gear 20, and a shaft hole 22b into which the first tip portion 30a is inserted so as to be integrally rotatable with the first tip portion 30a. The external teeth 22a have a larger number of teeth than the external teeth 20a. The connect gear 22 rotates about a first tip portion 30a that penetrates the holding hole 28b of the retainer 28.

The second EA mechanism 54A has a torsion bar 30 which is an EA member. The torsion bar 30 has a first tip portion 30a and a second tip portion 30b on both sides in the axial direction.

The retainer 29 has a holding hole 29d that rotatably holds the second tip portion 30b of the torsion bar 30, a boss 29a that rotatably holds the idle gear 26, and a holding hole 29c that rotatably holds the rotating body 27. And have.

The second reduction mechanism 52A is an example of the second reduction mechanism 52 (see FIG. 2), and has a connect gear 32, an idle gear 26, and a drive gear 23. The second reduction mechanism 52A shares the clutch 25 and the drive gear 23.

The connect gear 32 has an external tooth 32a that constantly meshes with the external tooth 26a of the idle gear 26, and a shaft hole 32b into which the second tip portion 30b is inserted so as to be integrally rotatable with the second tip portion 30b. The connect gear 32 rotates about a second tip portion 30b that penetrates the holding hole 29d of the retainer 29.

The idle gear 26 has external teeth 26a in which both the external teeth 32a of the connect gear 32 and the external teeth 23a of the drive gear 23 are always meshed with each other, and a shaft hole 26b into which the boss 29a is inserted.

The drive gear 23 has external teeth 23a having more teeth than the external teeth 26a of the idle gear 26, and a shaft hole 23b into 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 (torsion bar 7 in this embodiment), that is, is located 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 Paul 41.

The drive gear 23 is rotatably supported by a tip portion 7b coaxial with the rotation shaft of the spool 4, and rotates according to the rotation of the output shaft 12a of the motor 12. 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. The drive gear 23 has an outer diameter larger than that of the idle gear 26, and the outer teeth 23a are formed. The external teeth 23a of the drive gear 23 are connected to the output shaft 12a of the motor 12 via the second reduction mechanism 52A, the second EA mechanism 54A, and the first reduction mechanism 51A. The drive gear 23 is an example of the first rotating member.

The clutch outer 24 is rotatably supported coaxially with the drive gear 23 and is directly or indirectly connected to the spool 4. In the present 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 the shaft hole 27b of the rotating body 27 so as to be integrally rotatable with the rotating body 27, and a shaft hole 24b through which the tip portion 7b penetrates. The clutch outer 24 is an example of a second rotating member.

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

The clutch 25 includes a drive gear 23, a clutch outer 24 that is rotatably supported by the drive gear 23, a pair of clutch pawls 41 provided on the drive gear 23, and a pair of clutch pawls 41 for urging the drive gear 23. It has a clutch spring 42.

A pair of bosses 23e and 23h, a pair of mounting portions 23c and 23f, and a pair of stoppers 23d and 23g are formed so as to project from the end surface 23i of the drive gear 23. Ratchet internal teeth 24d are formed inside the outer peripheral wall 24c of the clutch outer 24.

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

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

The clutch spring 42a includes the mounting portion 23c and the pressed portion 41ab so as to urge the pressed portion 41ab in the direction approaching the ratchet internal teeth 24d and the claw portion 41aa in the direction away from the ratchet internal teeth 24d. It is an urging member arranged between them. 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 movement of the pressed portion 41ab in the direction approaching the ratchet internal teeth 24d is restricted by the stopper 23d so that the pressed portion 41ab does not come into contact with the ratchet internal teeth 24d.

Similarly, the clutch spring 42b urges the pressed portion 41bb in the direction closer to the ratchet internal tooth 24d and the claw portion 41ba in the direction away from the ratchet internal tooth 24d, so that the mounting portion 23f and the pressed portion It is an urging member arranged between 41bb and 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. The movement of the pressed portion 41bb in the direction approaching the ratchet internal teeth 24d is restricted by the stopper 23g so that the pressed portion 41bb does not come into contact with the ratchet internal teeth 24d.

Therefore, as shown in FIG. 11, when the rotation of the drive gear 23 is stopped, 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 according to the urging force of the clutch spring 42a. Tooth. That is, the claw portion 41aa does not engage with the ratchet internal tooth 24d.

Similarly, as shown in FIG. 11, when the rotation of the drive gear 23 is stopped, 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 urging force of the clutch spring 42b. Will be done. That is, the claw portion 41ba does not engage with the ratchet internal teeth 24d.

On the other hand, in a state where the output shaft 12a of the motor 12 is rotating, the drive gear 23 is also rotating around the shaft hole 24b due to the rotation of the motor gear 20 and the connect gear 22 described above. 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 seatbelt 104 due to the rotation of the output shaft 12a, the clutch pawl 41a moves by the centrifugal force while resisting the urging force of the clutch spring 42a. The clutch pawl 41a moved by centrifugal force engages with the ratchet internal teeth 24d of the clutch outer 24 (see FIG. 12). That is, the claw portion 41aa engages with the ratchet internal tooth 24d. On the contrary, when the drive gear 23 rotates in the direction corresponding to the pull-out direction of the seat belt 104 due to the rotation of the output shaft 12a, the clutch pawl 41a approaches the ratchet internal teeth 24d by the stopper 23d even if the centrifugal force acts. Movement to is restricted. Therefore, the engagement between the clutch pawl 41a and the ratchet internal teeth 24d is prevented (see FIG. 11). That is, the claw portion 41aa does not engage with the ratchet internal tooth 24d.

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

Therefore, in a state where the drive gear 23 is rotated in the direction corresponding to the winding direction of the seat belt 104 due to the rotation of the output shaft 12a, the claw portions 41aa and 41ba of the clutch pawls 41a and 41b are engaged with the ratchet internal teeth 24d. The state is maintained. In this engaged state, the rotational power of the output shaft 12a is the motor gear 20, the connect gear 22, the second EA mechanism 54A, the connect gear 32, the idle gear 26, the drive gear 23, the pair of clutch cowls 41, and the clutch outer 24. It is transmitted by the route. The clutch outer 24 is connected to the inner peripheral side of the spool 4 via a 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.

On the other hand, when the drive gear 23 is rotated in the direction corresponding to the pull-out direction of the seat belt 104 due to the rotation of the output shaft 12a, the claw portions 41aa and 41ba of the clutch pawls 41a and 41b do not engage with the ratchet internal teeth 24d. The state is maintained. Further, since the rotation of the drive gear 23 is stopped when the rotation of the output shaft 12a is stopped, the state in which the claw portions 41aa and 41ba of the clutch pawls 41a and 41b are not engaged with the ratchet internal teeth 24d is maintained. Will be done. In these non-engaged states, the rotational force of the rotating shaft of the spool 4 is transmitted in the route of the rotating body 27 and the clutch outer 24, but is not transmitted to the drive gear 23. Therefore, in such a non-engaged state, the rotational force of the rotating shaft of the spool 4 is not transmitted to the output shaft 12a. That is, the transmission of the rotational force from the rotary shaft of the spool 4 to the output shaft 12a is cut off.

As described above, the clutch 25 is a one-way clutch that blocks the transmission of the rotational force from the spool 4 to the motor 12 and transmits the rotational force from the motor 12 to the spool 4. Therefore, since the transmission of the rotational force from the spool 4 to the motor 12 is cut off by the clutch 25, the occupant 111 can smoothly pull out the seat belt 104 from the retractor 1 or wind it around the retractor 1. 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 a collision.

FIG. 13 is a front view of the seatbelt retractor according to the second embodiment. FIG. 14 is a right side view of the seatbelt retractor according to the second embodiment. FIG. 15 is a left side view of the seatbelt retractor according to the second embodiment. FIG. 16 is a diagram showing the cut surface of the seatbelt retractor according to the second embodiment in arrow CC (see FIG. 15). FIG. 17 is an exploded perspective view of the seatbelt retractor according to the second embodiment.

The retractor 1B shown in FIGS. 13 to 17 is an example of a seatbelt retractor, and is a specific example of the retractor 1 shown in FIG. The retractor 1B includes a first EA mechanism 53A which is an example of the first EA mechanism 53 and a second EA mechanism 54B which is an example of the second EA mechanism 54. The first EA mechanism 53A generates a base load BN by deforming the torsion bar 7 provided between the spool 4 and the lock mechanism 6. The second EA mechanism 54B limits the increase in the limiting load LN by deforming the plate 43 provided between the motor 12 and the spool 4. The torsion bar 7 is an example of a first EA member, and the plate 43 is an example of a second EA member. Hereinafter, the configuration of the retractor 1B will be described with reference to FIGS. 13 to 17. The description of the same configuration and effect as that of the retractor 1A will be omitted or simplified by referring to the above description.

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 reduction mechanism 51B, a second EA mechanism 54B, a second reduction mechanism 52B, and a clutch 25. The rotating body 27 may be an element of the power transmission mechanism 21B.

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

The retainer 29 includes a through hole 29e through which the output shaft 12a of the motor 12 penetrates, a shaft 29b that rotatably holds the second EA mechanism 54B, a boss 29a that rotatably holds the idle gear 26, and a rotating body 27. Has a holding hole 29c for rotatably holding the.

The first reduction mechanism 51B is an example of the first reduction mechanism 51 (see FIG. 2), and has a connect gear 32 and a plate holding gear 45. The first reduction mechanism 51B shares the plate holding gear 45 with the second EA mechanism 54B.

The connect gear 32 is a motor gear rotatably attached to the output shaft 12a of the motor 12. The connect gear 32 has external teeth 32a and a shaft hole 32b into which the output shaft 12a is inserted.

The plate holding gear 45 has an external tooth 45a that constantly meshes with the external tooth 32a of the connect gear 32, and a shaft hole 45b into which the shaft 29b is inserted. The external teeth 45a have a larger number of teeth than the external teeth 32a. The plate holding gear 45 rotates about the shaft 29b.

The second EA mechanism 54B has a plate 43 which is an EA member, and a pair of plate holding gears 44 and 45 that sandwich and hold the plate 43 from both sides. Next, the configuration of the second EA mechanism 54B will be described with reference to FIGS. 18 to 21.

FIG. 18 is a perspective view of the first plate holding gear 44. FIG. 19 is a perspective view of the second plate holding gear 45. FIG. 20 is a diagram showing a state before the operation of the plate 43. FIG. 21 is a diagram showing an operating state of the plate 43.

The second EA mechanism 54B includes a plate holding gear 44 arranged on the inner peripheral side of the plate holding gear 45, and a plastically deformable annular plate 43. The plate 43 is, for example, a strip-shaped or linear spring.

The plate holding gear 44 has a substantially disk shape, and has external teeth 44a that constantly mesh with the external teeth 26a of the idle gear 26.

20 and 21 are plan views of the plate holding gear 45 as viewed from the outside, and the outer shape of the plate 43 is shown by a solid line in order to improve visibility.

The plate 43 has an inner end 43a, an outer end 43b, and an intermediate 43c between the inner end 43a and the outer end 43b. The inner end portion 43a is fixed to the groove 44c formed in the outer peripheral portion 44d of the convex portion 44e of the plate holding gear 44. The outer end portion 43b is fixed to the groove 45c formed in the inner peripheral portion 45d of the recess 45e of the plate holding gear 45. The intermediate portion 43c has an outer peripheral extending portion P1, a bent portion P2, and an inner peripheral extending portion P3. The outer peripheral extending portion P1 is a portion extending from the inner end portion 43a along the outer peripheral portion 44d in the belt pulling direction. The bent portion P2 is located between the outer peripheral extending portion P1 and the inner peripheral extending portion P3, and is a portion that is turned back by 180 ° in the annular space S formed between the outer peripheral portion 44d and the inner peripheral portion 45d. Is. The inner peripheral extension portion P3 is a portion extending along the inner peripheral portion 45d in the belt winding direction.

When a load equal to or greater than the set value of the plate 43 is generated between the first plate holding gear 44 and the second plate holding gear 45, the second plate holding gear 45 is mounted on the first plate holding gear 44. The plate 43 is started to be pushed, and the plate 43 is deformed along the inner peripheral portion 45d. The first plate holding gear 44 rotates in the direction opposite to that of the second plate holding gear 45. The deformation of the plate 43 limits the excessive load generated by the motor 12 and absorbs energy. Although the plate 43 is mounted on the first plate holding gear 44 in the illustrated form, it may be mounted on the second plate holding gear 45.

Although the seatbelt retractor and the seatbelt device have been described above by the embodiment, the present invention is not limited to the above embodiment. Various modifications and improvements, such as combinations and substitutions with some or all of the 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 reduction mechanism 51 and the second reduction mechanism 52 is not limited to two, and may be one or three or more.

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 gear 21 Power transmission mechanism 22 Connect gear 23 Drive gear 24 Clutch outer 25 Clutch 26 Idle gear 27 Rotating body 28 Retainer 29 Retainer 30 Torsion bar 32 Connect gear 41 Clutch poul 43 Plate 44 Plate holding gear 45 Plate holding gear 51 First deceleration mechanism 52 Second deceleration mechanism 53 First EA mechanism 54 Second EA mechanism 55 1st part 56 2nd part

Claims (16)

The spool that winds up the seat belt and
A lock mechanism that allows the spool to rotate when not operating and prevents the spool from rotating in the pull-out direction of the seat belt when operating.
A first energy absorption mechanism that is deformed by the rotation of the spool in the pull-out direction and the rotation prevention by the lock mechanism, and
A power transmission mechanism that adds a second load generated by the motor and the deceleration mechanism to the first load generated by the deformation of the first energy absorption mechanism.
A seatbelt retractor including a second energy absorbing mechanism that limits an increase in a limiting load generated by adding the second load to the first load by its own deformation. The seatbelt retractor according to claim 1, wherein the motor and the spool are connected to each other via the second energy absorption mechanism. The seatbelt retractor according to claim 2, wherein the speed reduction mechanism includes a first speed reduction mechanism and a second speed reduction mechanism that are interconnected via the second energy absorption mechanism. The seatbelt retractor according to claim 3, wherein the second energy absorption mechanism and the spool are connected via the second deceleration mechanism. The power transmission mechanism according to any one of claims 2 to 4, wherein the power transmission mechanism has a clutch that blocks the transmission of force from the spool to the motor and allows the transmission of force from the motor to the spool. Seat belt retractor. The clutch cuts off the transmission of force from the spool to the output shaft when the rotation of the output shaft of the motor is stopped, and from the output shaft to the spool when the output shaft is rotating. The seatbelt retractor according to claim 5, which allows the transmission of the force of the vehicle. The clutch
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 that is rotatably supported coaxially with the first rotating member and is directly or indirectly connected to the spool.
It has a clutch pawl provided on the first rotating member, and has.
The clutch pawl moves by centrifugal force due to the rotation of the first rotating member and engages with the second rotating member, and the second rotating member is stopped in rotation. The seatbelt retractor according to claim 6, which does not engage with a rotating member. The clutch pawl moves by the centrifugal force while resisting the urging force of the urging member and engages with the second rotating member. In a state where the rotation of the first rotating member is stopped, the clutch pawl is attached. The seatbelt retractor according to claim 7, which is held at a position where it does not engage with the second rotating member according to the force. The seatbelt retractor according to claim 7 or 8, wherein the clutch pawl is swingably supported by an end surface of the first rotating member and engages with the internal teeth of the second rotating member by the centrifugal force. .. A pretensioner having a rotating body that rotates the spool in the winding direction of the seat belt during operation is provided.
The seatbelt retractor according to any one of claims 5 to 9, wherein the clutch and the spool are connected to each other via the rotating body. The first energy absorbing mechanism has a first portion that engages with the spool and a second portion that is locked by the locking mechanism.
The seatbelt retractor according to any one of claims 1 to 10, wherein the power transmission mechanism transmits the second load to the side of the first portion. The sheet according to any one of claims 1 to 11, wherein the first energy absorption mechanism generates the first load by deformation of a torsion bar provided between the spool and the lock mechanism. Belt retractor. The seatbelt according to any one of claims 1 to 12, wherein the second energy absorption mechanism limits an increase in the limiting load by deforming a torsion bar provided between the motor and the spool. Retractor. The seatbelt retractor according to any one of claims 1 to 12, wherein the second energy absorption mechanism limits an increase in the limiting load by deforming a plate provided between the motor and the spool. .. The seatbelt retractor according to any one of claims 1 to 14, further comprising a control unit that adjusts the second load by controlling the motor. A seatbelt device comprising the seatbelt retractor according to any one of claims 1 to 15, the seatbelt, a tongue attached to the seatbelt, and a buckle to which the tongue is detachably engaged. ..