JP2022121998A - Seat belt retractor and seat belt device - Google Patents

Abstract

To provide a seat belt retractor which can flexibly adjust load acting on a seat belt in emergency.SOLUTION: A seat belt retractor is provided, comprising: a spool which winds up a seat belt; a rotor rotatable together with the spool; a first energy absorption mechanism connected to the rotor relatively unrotatably; a lock mechanism locking the first energy absorption mechanism during operation; a motor rotating the rotor; a second energy absorption mechanism relatively unrotatably connected to the spool and the rotor; and a stopper locking the rotor during operation. In the seat belt retractor, the first energy absorption mechanism deforms when the spool and the rotor rotate in a pull-out direction of the seat belt in the state that the first energy absorption mechanism is locked by the lock mechanism, and the second energy absorption mechanism deforms when load acting on itself reaches set value by the spool rotating in the pull-out direction.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to seat belt retractors and seat belt devices.

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Such a seatbelt device is provided with a seatbelt retractor that retracts the seatbelt so that it can be withdrawn.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 operates 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, 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 force generated by twisting a torsion bar and an electric EA mechanism that utilizes motor force (see, for example, Patent Document 1).

JP-A-2001-270423 Japanese Unexamined Patent Application Publication No. 2020-172192

In recent years, there has been a demand for more flexible adjustment of the load (EA load) that limits the withdrawal of the seat belt in an emergency.

The present disclosure provides a seatbelt retractor and a seatbelt device capable of flexibly adjusting the EA load.

This disclosure is
a spool for winding the seat belt;
a rotating body rotatable together with the spool;
a first energy absorbing mechanism coupled to the rotating body so as not to rotate relative to it;
a locking mechanism that locks the first energy absorbing mechanism when activated;
a motor that rotates the rotating body;
a second energy absorbing mechanism that is non-rotatably connected to the spool and the rotating body;
a stopper that locks the rotating body during operation,
The first energy absorbing mechanism is deformed when the spool and the rotating body rotate in the seat belt withdrawal direction in a state locked by the locking mechanism,
The second energy absorbing mechanism provides a seat belt retractor that deforms when the spool rotates in the withdrawal direction and the load acting thereon reaches a set value. 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 flexibly adjust the load acting on the seatbelt in an emergency.

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 changes in EA 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 front view of part of the internal structure of the seat belt retractor. FIG. 9 is a cross-sectional view showing a state before the stopper is actuated, taken along line BB (see FIG. 9); FIG. 10 is a cross-sectional view showing a state after the stopper is actuated, taken along line BB (see FIG. 9);

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 pulled out from the retractor 103 when an acceleration/deceleration or vehicle angle equal to or greater than a predetermined value is detected at the time of vehicle collision or the like. 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, for example, a seatbelt retractor that includes a spool 4, a rotating body 52, a first EA mechanism 53, a lock mechanism 6, a power transmission mechanism 21, a second EA mechanism 54, and a stopper 57.

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 rotating body 52 is a member that can rotate together with the spool 4 and rotates together with the spool 4 until it is locked by a stopper 57 .

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 seat belt 104 withdrawal direction 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. The first EA mechanism 53 is connected to the rotor 52 so as not to rotate relative to it. The first EA mechanism 53 is deformed when the spool 4 and rotating body 52 rotate in the seat belt withdrawal direction while locked by the lock mechanism 6 .

The power transmission mechanism 21 has, for example, a motor 12 that rotates the rotating body 52 . 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 output of the motor 12. ) is added. The number of reduction mechanisms 51 that reduce and transmit the rotation of the output shaft of the motor 12 may be one or more. FIG. 2 shows one speed reduction mechanism 51 . The rotating body 52 may include a speed reduction mechanism. The base load BN and the assist load AN contribute to the load (EA load) that restricts withdrawal of the seat belt 104 in an emergency. The retractor 1 reduces the load acting on the seat belt 104 by restricting the withdrawal of the seat belt 104 with the EA load in an emergency.

The second EA mechanism 54 is connected to the spool 4 and the rotor 52 so as not to rotate relative to each other. The second EA mechanism 54 limits the increase in EA load by its own deformation. The second EA mechanism 54 is deformed when the load acting on it reaches a set value due to the rotation of the spool 4 in the direction in which the seat belt 104 is pulled out. 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 mitigate the energy of the occupant.

The stopper 57 is a member that allows the rotating body 52 to rotate when not in operation and locks the rotating body 52 when in operation. The stopper 57 prevents rotation of the rotating body 52 by locking the rotating body 52 .

Next, an example of operation in an emergency such as a vehicle collision will be described.

In an emergency, 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 . The output of the motor 12 is transmitted to the rotating body 52 via the speed reduction mechanism 51 and the clutch 25 to rotate the rotating body 52, and the spool 4 rotates in the belt winding direction as the rotating body 52 rotates. Thereafter, 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 rotating body 52, which is connected to the first EA mechanism 53 so as not to rotate relative thereto, is prevented, and the rotation of the rotating body 52 is prevented. As a result, the rotation of the spool 4 in the belt withdrawing direction is prevented. However, since the spool 4 tends to rotate in the belt withdrawing direction together with the rotator 52, the rotation of the spool 4 and the rotator 52 in the withdrawing direction of the seat belt 104 and the prevention of rotation by the lock mechanism 6 prevent the first EA mechanism from rotating. 53 is deformed. Since the EA load generated by the deformation of the first EA mechanism 53 restricts the withdrawal of the seat belt 104 from the spool 4 , the occupant's energy is absorbed and mitigated by the deformation of the first EA mechanism 53 .

FIG. 3 is a diagram illustrating changes in the EA load 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 withdrawal direction after the lock mechanism 6 is locked, and the vertical axis represents the EA load generated by the retractor 1 (also referred to as "limited load LN"). ).

As shown in FIG. 3, the power transmission mechanism 21 generates a limit load LN by adding an assist load AN generated by the output 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 the second limit load N2 by the second EA mechanism 54. FIG. The first limit load N1 can be generated by deformation of the first EA mechanism 53 in a state where force transmission between the motor 12 and the rotating body 52 is interrupted by disengagement of the clutch 25 or the like. maximum load. The second limit load N2 is the maximum load that can be generated by deformation of the second EA mechanism 54. FIG. On the other hand, even if the limit load LN becomes excessive for some reason, as shown by the waveform c, the limit load LN is limited so as not to exceed the upper limit load Lb. can.

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 d and e in FIG. Waveform d indicates the case where the motor 12 is controlled so as to increase the assist load AN rise speed, and waveform e indicates the case where the motor 12 is controlled so as to slow the assist load AN rise speed.

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 increasing or decreasing the negative assist load AN added 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 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.

Further, when force transmission between the motor 12 and the rotor 52 is interrupted due to disengagement of the clutch 25, failure of the power transmission mechanism 21, or the like, the assist load AN is not added to the base load BN. Even in such a case, when the rotor 52 is locked by the stopper 57, the limit load LN can be limited to the upper limit load Lb as shown by the waveform i. Also, the sum of the base load BN and the assist load AN may become excessive for some reason. Even in such a case, when the rotor 52 is locked by the stopper 57, the limit load LN can be limited to the upper limit load Lb as shown by the waveforms j and k. That is, in such cases, the load acting on the seat belt 104 can be limited by the upper limit load Lb, so that an excessive load can be prevented from acting on the seat belt 104 . The stroke amount Ss is an amount corresponding to an amount of rotation preset by the stopper 57 as an amount of rotation for the stopper 57 to start locking the rotating body 52 .

Thus, according to the retractor 1, the EA load can be flexibly adjusted.

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.

The deceleration mechanism 51 decelerates the rotation of the output shaft 12 a of the motor 12 and transmits it to the rotating body 52 .

Moreover, it is preferable that the power transmission mechanism 21 has a clutch 25 that blocks transmission of force from the rotating body 52 to the motor 12 and allows transmission of force from the motor 12 to the rotating body 52 . By providing the clutch 25 that cuts off the transmission of force from the rotating body 52 to the motor 12, for example, the powerful winding torque of the seat belt 104 by the pretensioner 8 at the time of collision causes the rotating body 52 that rotates together with the spool 4 to move. transmission to the motor 12 can be prevented. Further, if the rotating body 52 and the output shaft of the motor 12 are connected via the speed reduction mechanism 51, 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 motor 12 is The load is transmitted to the occupant operating the seat 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 via the rotor 52 and transmits torque from the motor 12 to the spool 4 via the rotor 52. . Therefore, transmission of rotational force from the spool 4 to the motor 12 via the rotating body 52 is interrupted by the clutch 25, so that the occupant can smoothly pull out the seat belt 104 from the retractor 1 or allow the retractor 1 to wind the seat belt 104. become.

The clutch 25 cuts off transmission of force from the rotating body 52 to the output shaft 12a when the output shaft 12a of the motor 12 stops rotating, and rotates from the output shaft 12a when the output shaft 12a is rotating. Allows transmission of force to body 52 . 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 rotating body 52). 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 rotor 52 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.

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 rotating body 52 and the lock mechanism 6. FIG. The second EA mechanism 54A limits the increase of the limit load LN by deformation of the torsion bar 30 provided between the rotating body 52 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. 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 rotor 52, a first EA mechanism 53A, a vehicle sensor 5, a lock mechanism 6, a power transmission mechanism 21A, a return spring 65, a second EA mechanism 54A and a stopper 57.

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 portions 2b and 2c facing each other 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 rotating body 52 is a member that can rotate together with the spool 4 and rotates together with the spool 4 until it is locked by a stopper 57 . In this example, the rotating body 52 rotates integrally with the spool 4 until it is locked by the stopper 57, and after being locked by the stopper 57, the spool 4 rotates relative to the rotating body 52. It is fitted to the inner wall of the cylindrical spool 4 with a matching force. The rotor 52 is a cylindrical shaft gear having a flange with external teeth 52a.

The first EA mechanism 53A has a torsion bar 7 that is connected to the rotor 52 so as not to rotate relative to it. The torsion bar 7 is an example of a first torsion bar. The torsion bar 7 has a first connecting portion 15 that is non-rotatably connected to the rotor 52 and a second connecting portion 16 that is locked by the lock mechanism 6 . These connecting portions are provided at locations separated from each other in the axial direction. In this example, the first connecting portion 15 is connected to the inner wall of the cylindrical rotor 52 so as not to rotate relatively, and the second connecting portion 16 is connected to the inner wall of the cylindrical portion 17a of the locking base 17 so as not to rotate relatively. do.

The torsion bar 7 has a distal end portion 7a protruding from the second connecting portion 16 in the axial direction. The tip portion 7a passes through the locking base 17 and is rotatably supported by the retainer 61 via the bearing cap 62. As shown in FIG. The retainer 61 is fixed to the side surface portion 2 b of the frame 2 .

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 supported so as to be integrally rotatable with a second connecting portion 16, which will be described later, and holds the pawl swingably. The locking base 17 is an example of a locking member, normally rotates together with the spool 4 and the rotating body 52, and prevents the spool 4 from rotating 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 spherical body 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 and the rotor 52 in the seat belt 104 withdrawal direction is also prevented.

The power transmission mechanism 21A is an example of the power transmission mechanism 21 shown in FIG. 21 A of power transmission mechanisms are provided with the motor 12, the retainer 28, the reduction mechanism 51, the gear case 29, and the clutch 25. As shown in FIG.

The motor 12 generates power to rotate the spool 4 and the rotor 52 . Motor 12 is secured to retainer 28 .

The retainer 28 has a through hole 28a through which the output shaft 12a of the motor 12 passes, and a holding surface 28b that holds the drive gear 23 of the clutch 25 rotatably.

The deceleration mechanism 51 has a motor gear 20 and a connect gear 22, and decelerates and transmits the rotation of the output shaft 12a of the motor 12. FIG.

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 22 has external teeth 22a that always mesh with the external teeth 20a of the motor gear 20, and a shaft hole 22b into which a boss projecting from the gear case 29 is inserted. The external teeth 22a have a greater number of teeth than the external teeth 20a. The connect gear 22 rotates around an axis projecting from the gear case 29 .

Gear case 29 has a boss that rotatably holds idle gear 26 and a boss that rotatably holds clutch gear 24 .

The idle gear 26 has external teeth 26a that are always meshed with both the external teeth 52a of the rotor 52 and the external teeth 24a of the clutch gear 24, and a shaft hole 26b into which the boss of the gear case 29 is inserted.

The clutch 25 includes a drive gear 23, a clutch gear 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 .

The power of the motor 12 is transmitted to the drive gear 23 via the motor gear 20 and the connect gear 22, and the drive gear 23 rotates as the output shaft 12a of the motor 12 rotates.

The clutch gear 24 is rotatably supported coaxially with the drive gear 23 and is connected to the rotating body 52 via the idle gear 26 .

When the drive gear 23 stops rotating, the clutch pawl 41 is held at a position where it does not engage with the ratchet internal teeth of the clutch gear 24 due to the biasing force of the clutch spring 42 .

On the other hand, when the output shaft 12a of the motor 12 is rotating, the rotation of the motor gear 20 and the connect gear 22 causes the drive gear 23 to rotate. Centrifugal force acts on the clutch pawl 41 when the drive gear 23 rotates.

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 41 is moved by the centrifugal force while resisting the biasing force of the clutch spring 42. Clutch pawl 41 moved by centrifugal force engages with ratchet internal teeth of clutch gear 24 . 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 41 is prevented from being pulled out of the clutch gear 24 by the stopper of the drive gear 23 even if the centrifugal force acts thereon. Movement in the direction approaching the ratchet internal teeth is restricted. Therefore, the engagement between the clutch pawl 41 and the ratchet internal teeth is prevented.

Therefore, while the drive gear 23 is rotating 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 41 is kept engaged with the ratchet internal teeth. In this engaged state, the rotational power of the output shaft 12 a is transmitted through the motor gear 20 , the connect gear 22 , the clutch gear 24 , the idle gear 26 and the rotor 52 in sequence. 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 clutch pawl 41 is kept out of engagement with the ratchet internal teeth. Further, when the rotation of the output shaft 12a is stopped, the rotation of the drive gear 23 is also stopped, so that the clutch pawl 41 is maintained in a state where it does not engage with the ratchet internal teeth. In these disengaged states, the rotational force of the rotating shaft of the spool 4 is transmitted through the rotating body 52 , the idle gear 26 and the clutch gear 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 rotor 52 to the motor 12 and transmits torque from the motor 12 to the rotor 52 . 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.

The return spring 65 urges the spool 4 to rotate in the winding direction of the seat belt 104 . The return spring 65 is housed in a spring case 66 fixed to the side portion 2c.

The second EA mechanism 54A has a torsion bar 30 that is connected to the rotor 52 so as not to rotate relative to it. The torsion bar 30 is an example of a second torsion bar. The torsion bar 30 has a third connection portion 18 that is non-rotatably connected to the spool 4 and a fourth connection portion 19 that is non-rotatable to the rotor 52 . These connecting portions are provided at locations separated from each other in the axial direction. In this example, the third connecting portion 18 is connected to the inner wall of the cylindrical spool 4 so as not to rotate relatively, and the fourth connecting portion 19 is connected to the inner wall of the cylindrical rotating body 52 so as not to rotate relatively.

The torsion bar 30 has a tip portion 30a axially protruding from the third connecting portion 18 . The tip portion 30 a is rotatably supported by a spring case 66 via a bush nut 64 . The torsion bar 30 has a diameter larger than that of the torsion bar 7 . The torsion bar 30 is arranged coaxially with the torsion bar 7 .

The stopper 57 is an annular member that allows the rotating body 52 to rotate when not in operation and locks the rotating body 52 when in operation. The stopper 57 is arranged inside the cylindrical rotating body 52 and is connected to the inner wall of the rotating body 52 so as not to rotate relative to the rotating body 52 .

Next, the movement of each part of the retractor 1A in an emergency such as a vehicle collision will be described. FIG. 9 is a front view of part of the internal structure of the retractor 1A. FIG. 10 is a cross-sectional view showing the state before the stopper 57 is actuated, taken along line BB (see FIG. 9). FIG. 11 is a cross-sectional view showing the state after the stopper 57 is actuated, taken along line BB (see FIG. 9).

In FIG. 10 , when the lock mechanism 6 is activated, the first EA mechanism 53 A locks the rotation of the locking base 17 , thereby locking the torsion bar 7 at the second connecting portion 16 . As a result, the spool 4 rotates in the direction in which the seat belt 104 is pulled out, so that the rotor 52 rotates together with the spool 4 . Since the torsion bar 7 is connected to the rotating body 52 by the first connecting portion 15 by press fitting or the like so as not to be relatively rotatable, it starts torsionally deform.

The stopper 57 operates to lock the rotating body 52 when the torsional deformation of the torsion bar 7 of the first EA mechanism 53A reaches a predetermined amount of deformation. The stopper 57 may operate to lock the rotating body 52 when its rotation reaches a set amount of rotation. The torsion bar 30 of the second EA mechanism 54A begins torsionally deform as the spool 4 rotates in the direction in which the seat belt 104 is pulled out while the rotor 52 is locked by the stopper 57 . This is because the torsion bar 30 is connected to the rotating body 52 by the fourth connecting portion 19 by press-fitting or the like so as not to be relatively rotatable. The torsion bar 30 begins torsionally deform when the load acting on it reaches a set value.

The stopper 57 operates depending on the rotation of the rotating body 52 . In this example, the stopper 57 has a mechanism that rotates depending on the rotation of the rotating body 52, and operates to lock the rotating body 52 when a preset amount of rotation (set amount of rotation) is reached. The rotation of the stopper 57 stops when the set amount of rotation is reached. Since the stopper 57 is connected to the rotor 52 so as not to rotate relative to it, the rotation of the rotor 52 is locked when the stopper 57 stops rotating.

In this example, the stopper 57 moves along the rotating shaft 67 while rotating around the rotating shaft 67 of the rotor 52 . The rotating body 52 is arranged coaxially with the spool 4 . A male thread is formed on the cylindrical portion 17 a of the locking base 17 , and a female thread is formed on the inner surface of the stopper 57 . Thereby, the stopper 57 moves along the axial direction (rotating shaft 67) of the cylindrical portion 17a while rotating together with the rotating body 52 (see FIG. 11). The rotation and movement of the stopper 57 stops when it reaches the locking base 17 of the locking mechanism 6, as shown in FIG. 11, for example. The rotating body 52 is locked when the stopper 57 stops rotating and moving.

By locking the rotating body 52, only the spool 4 rotates, and the torsion bar 30 of the second EA mechanism 54A begins torsionally deform.

Thus, the torsion bar 30 of the second EA mechanism 54A rotates in the pull-out direction with the rotating body 52 locked by the stopper 57, and when the load acting on the torsion bar 30 reaches the set value, ,transform. As a result, the load acting on the seat belt 104 is limited by the EA load due to the deformation of the torsion bar 30 of the second EA mechanism 54A, so that the load acting on the seat belt 104 can be suppressed from becoming excessive. For example, in a state where the torsion bar 7 of the first EA mechanism 53A is deformed and force is being transmitted from the motor 12 to the rotating body 52, the load acting on the torsion bar 30 of the second EA mechanism 54A is the set value. , the torsion bar 30 of the second EA mechanism 54A is deformed.

According to the retractor 1A having the structure described above, the torsion bar 30 of the second EA mechanism 54A rotates the spool 4 in the pull-out direction in a state in which the rotor 52 is not locked by the stopper 57. Even if the applied load reaches the set value, it will be deformed. For example, the load generated by the deformation of the torsion bar 7 of the first EA mechanism 53A and the output of the motor 12 is applied to the torsion bar 30 of the second EA mechanism 54A when the rotor 52 is not locked to the stopper 57. Even if it reaches the set value, it will transform.

Further, in the retractor 1A, a clutch 25 is mounted on the power transmission path between the output shaft 12a of the motor 12 and the rotor 52. As shown in FIG. When the clutch 25 is actuated, the output shaft 12a of the motor 12 is connected to the rotor 52 via a plurality of gears. When the clutch 25 is not operating, the load generated by the output of the motor 12 is not transmitted to the rotating body 52 and the spool 4 .

Further, according to the retractor 1A, the EA load is secured by the first EA mechanism 53A, and even if the EA load by the motor 12 does not occur due to some abnormality, the stopper 57 is operated, whereby the second EA mechanism It is possible to generate an EA load of 54A. As a result, the occupant can be restrained more appropriately even when the EA load is not generated by the motor 12, for example, at the time of a collision with relatively high collision energy.

The retractor 1A may include spacers 63. As shown in FIG. A predetermined gap is set between the stopper 57 and the rotating body 52 so that the stopper 57 can move along the axial direction of the cylindrical portion 17 a of the locking base 17 . Therefore, rattling may occur between the stopper 57 and the rotating body 52 . Therefore, by filling this gap with a spacer 63 made of resin, for example, the rattling can be prevented.

Although the embodiments have been described above, the technology of the present disclosure 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.

1, 1A Retractor 2 Frame 4 Spool 5 Vehicle Sensor 6 Lock Mechanism 7 Torsion Bar 8 Pretensioner 10 Control Part 12 Motor 14 Lock Gear 15 First Connection Part 16 Second Connection Part 17 Locking Base 18 Third Connection Part 19 Fourth Connection Part 20 Motor gear 21 Power transmission mechanism 22 Connect gear 23 Drive gear 24 Clutch gear 25 Clutch 26 Idle gear 28 Retainer 29 Gear case 30 Torsion bar 41 Clutch pawl 51 Reduction mechanism 52 Rotator 53 First EA mechanism 54 Second EA mechanism 57 stopper 61 retainer 62 bearing cap 63 spacer 64 bush nut 65 return spring 66 spring case 67 rotating shaft

Claims (20)

a spool for winding the seat belt;
a rotating body rotatable together with the spool;
a first energy absorbing mechanism coupled to the rotating body so as not to rotate relative to it;
a locking mechanism that locks the first energy absorbing mechanism when activated;
a motor that rotates the rotating body;
a second energy absorbing mechanism that is non-rotatably connected to the spool and the rotating body;
a stopper that locks the rotating body during operation,
The first energy absorbing mechanism is deformed when the spool and the rotating body rotate in the seat belt withdrawal direction in a state locked by the locking mechanism,
The seat belt retractor, wherein the second energy absorbing mechanism is deformed when the load acting on the second energy absorbing mechanism reaches a set value due to rotation of the spool in the pulling direction. The second energy absorbing mechanism is deformed when the spool rotates in the pull-out direction with the rotating body locked by the stopper and the load acting on the second energy absorbing mechanism reaches the set value. 2. The seat belt retractor according to 1. The second energy absorbing mechanism is deformed when the spool rotates in the pull-out direction with the rotating body not locked by the stopper and the load acting on the second energy absorbing mechanism reaches the set value. Item 3. The seat belt retractor according to Item 1 or 2. The seatbelt retractor according to any one of claims 1 to 3, wherein the stopper operates to lock the rotating body when deformation of the first energy absorbing mechanism reaches a predetermined deformation amount. The seat belt retractor according to any one of claims 1 to 4, wherein the stopper operates depending on rotation of the rotating body. 6. The seat belt retractor according to claim 5, wherein said stopper rotates depending on rotation of said rotating body. 7. The seat belt retractor according to claim 6, wherein the stopper operates to lock the rotating body when its rotation reaches a set amount of rotation. rotation of the stopper stops when the set amount of rotation is reached;
8. The seat belt retractor according to claim 7, wherein said rotating body is locked by stopping rotation of said stopper. The seat belt retractor according to any one of claims 6 to 8, wherein the stopper moves along the rotation axis while rotating around the rotation axis of the rotating body. rotation and movement of the stopper stop upon reaching the locking mechanism;
10. The seat belt retractor according to claim 9, wherein said rotating body is locked by stopping rotation and movement of said stopper. The seatbelt retractor according to any one of claims 1 to 10, wherein the rotating body is arranged coaxially with the spool. The seat belt retractor according to any one of claims 1 to 11, wherein said rotating body rotates with said spool until locked by said stopper. 13. The seat belt retractor according to any one of claims 1 to 12, further comprising a clutch that blocks transmission of force from said rotating body to said motor and allows transmission of force from said motor to said rotating body. The seat belt retractor according to any one of claims 1 to 13, wherein said first energy absorbing mechanism has a first torsion bar that is non-rotatably connected to said rotor. 15. The seatbelt retractor according to claim 14, wherein said first torsion bar has a first connecting portion connected to said rotating body so as not to rotate relative thereto, and a second connecting portion locked by said locking mechanism. The seat belt retractor according to claim 14 or 15, wherein said second energy absorbing mechanism has a second torsion bar that is non-rotatably connected to said rotor. 17. The seat belt retractor of claim 16, wherein said second torsion bar is arranged coaxially with said first torsion bar. 18. The second torsion bar according to claim 16 or 17, having a third connecting portion that connects to said spool so as not to rotate relatively, and a fourth connecting portion that connects to said rotating body so as not to rotate relatively. seat belt retractor. 19. The seat belt retractor according to any one of claims 1 to 18, comprising a controller for controlling said motor. A seatbelt device comprising: the seatbelt retractor according to any one of claims 1 to 19; the seatbelt; a tongue attached to the seatbelt; and a buckle to which the tongue is detachably engaged. .

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