Seat belt retractor and seat belt device

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

[Technical field]

[0001] The present disclosure relates to a seat belt retractor and a seat belt device. [Background technology]

[0002] Seat belt devices installed in vehicles such as automobiles prevent occupants from being thrown out of their seats in an emergency (for example, when the vehicle experiences a large deceleration during a collision while the seat belt is fastened) by restraining the occupant with the seat belt.

[0003] Such a seat belt device is provided with a seat belt retractor that winds up the seat belt so that it can be withdrawn. In this seat belt retractor, the seat belt is wound around a spool when the seat belt is not worn, but is withdrawn and worn by the occupant when worn. In the event of an emergency such as the one described above, a locking means of the seat belt retractor is activated to prevent the spool from rotating in the belt withdrawing direction, thereby preventing the seat belt from being withdrawn, so that the occupant is restrained by the seat belt in the event of an emergency.

[0004] When an occupant is restrained by a seat belt in an emergency such as a vehicle collision, a large vehicle deceleration occurs, and the occupant tries to move forward due to a large inertia. As a result, 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 a particular problem for the occupant, it is desirable to limit it if possible.

[0005] Therefore, development of seat belt retractors equipped with an energy absorption mechanism (hereinafter also referred to as EA mechanism) that limits the load acting on the seat belt in an emergency while the seat belt is fastened, thereby absorbing and mitigating the energy of the occupant is underway. One such seat belt retractor is a retractor equipped with a mechanical EA mechanism that utilizes the force generated by the twisting of a torsion bar, and an electric EA mechanism that utilizes the force generated by a motor (for example, see Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2001-270423 A [Patent Document 2] JP 2020-172192 A Summary of the Invention [Problem to be solved by the invention]

[0007] In recent years, there has been a demand for more flexible adjustment of the load that limits the withdrawal of a seat belt in an emergency (EA load).

[0008] The present disclosure provides a seat belt retractor and a seat belt device capable of flexibly adjusting the EA load. [Means for solving the problem]

[0009] The present disclosure relates to A spool for winding the seat belt; A rotating body rotatable together with the spool; Connected to the rotating body so as not to rotate relative to the rotating body A first connecting portion and a second connecting portion provided at a position away from the first connecting portion. a first energy absorbing mechanism; A locking base is connected to the second connecting portion so as not to rotate relative to the second connecting portion. A locking mechanism; A motor that rotates the rotating body; The spool a third connecting portion that is connected to the first connecting portion so as not to rotate relative to the first connecting portion; Connected to the rotating body so as not to rotate relative to the rotating body and a fourth connecting portion, the third connecting portion and the fourth connecting portion being provided at positions separated from each other. a second energy absorbing mechanism; and vinegar a topper; The first energy absorption mechanism includes: Rotation of the locking base When the spool and the rotor are rotated in the seat belt withdrawing direction in the locked state, they are deformed, The second energy absorption mechanism includes: With the rotation of the rotating body locked by the stopper, The spool rotates in the unwinding direction. and,The present disclosure also provides a seat belt device including the seat belt retractor. Effect of the Invention

[0010] According to the technique of the present disclosure, it is possible to provide a seat belt retractor and a seat belt device that are capable of flexibly adjusting the load acting on the seat belt in an emergency. [Brief description of the drawings]

[0011] [Figure 1] 1 is a diagram illustrating an example of a configuration of a seat belt device according to an embodiment; [Diagram 2] 1 is a block diagram illustrating a configuration of a seat belt retractor according to an embodiment; [Diagram 3] FIG. 13 is a diagram illustrating an example of a change in EA load with respect to a stroke of a spool. [Figure 4] FIG. 1 is a front view of a seat belt retractor according to a first embodiment. [Diagram 5] FIG. 2 is a right side view of the seat belt retractor according to the first embodiment. [Figure 6] FIG. 1 is a left side view of a seat belt retractor according to a first embodiment. [Figure 7] 7 is a cross-sectional view of the seat belt retractor according to the first embodiment taken along an arrow AA (see FIG. 6). FIG. [Figure 8] 1 is an exploded perspective view of a seat belt retractor according to a first embodiment. [Figure 9] FIG. 2 is a front view of a portion of the internal structure of the seat belt retractor. [Figure 10] 10 is a cross-sectional view taken along the arrow BB (see FIG. 9) showing a state before the stopper is actuated. [Figure 11] 10 is a cross-sectional view taken along the arrow BB (see FIG. 9) showing a state after the stopper is actuated. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0013] Fig. 1 is a diagram illustrating a configuration of a seat belt device in an embodiment according to the present disclosure. The seat belt device 101 shown in Fig. 1 is an example of a seat belt device mounted on a vehicle. The seat belt device 101 includes, for example, a seat belt 104, a retractor 103, a shoulder anchor 106, a tongue 107, and a buckle 108.

[0014] The seat belt 104 is an example of a seat belt that restrains an occupant 111 seated in a vehicle seat 102, and is a belt-shaped member that is retracted and pulled out by a retractor 103. The seat belt is also called a webbing. A belt anchor 105 at the tip of the seat belt 104 is fixed to the seat 102 or a vehicle body in the vicinity of the seat 102.

[0015] The retractor 103 is an example of a seat belt retracting device that enables retracting or unretracting of the seat belt 104. When acceleration / deceleration or a vehicle angle equal to or greater than a predetermined value is detected during a vehicle collision or the like, the retractor 103 restricts the seat belt 104 from being unretracted from the retractor 103. The retractor 103 is fixed to the seat 102 or to a vehicle body in the vicinity of the seat 102. The retractor 103 is an example of a seat belt retractor.

[0016] The retractor 103 has a function of winding the seat belt 104 onto a spool by the power of the motor 103a. For example, before a vehicle collision, the retractor 103 operates the motor 103a based on a signal from a sensor such as a millimeter wave radar to wind the seat belt 104 onto the spool, and applies pretension to the seat belt 104 to quickly restrain the occupant with the seat belt 104. In addition, the retractor 103 operates the motor 103a to wind the seat belt 104 onto the spool when, for example, the tongue 107 is released from the buckle 108. The retractor 103 operates the motor 103a to adjust the tension of the seat belt 104 according to the driving situation (state of the vehicle), thereby improving the restraint of the occupant by the seat belt 104 and the comfort when wearing the seat belt 104.

[0017] The vehicle state refers to a state that indicates, for example, whether the seat belt 104 is pulled out, whether there is an occupant 111, the vehicle's traveling speed, the vehicle's acceleration, the steering operation, the accelerator operation, the brake operation, the operation of the buckle 108, the door operation, and the operation input of an in-vehicle selection switch that can be operated by an occupant.

[0018] 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, which has been withdrawn from the retractor 103, toward the shoulder of the occupant 111. The shoulder anchor 106 is fixed to the seat 102 or to a vehicle body in the vicinity of the seat 102.

[0019] 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.

[0020] The buckle 108 is a component into which a planar locking portion of a tongue 107 attached to the seat belt 104 is inserted and removed, and the tongue 107 is detachably connected to the buckle 108. The buckle 108 is fixed to the seat 102 or a vehicle body in the vicinity of the seat 102, for example.

[0021] 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 a 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 a lap belt portion 110 that restrains the waist of the occupant 111.

[0022] Fig. 2 is a block diagram illustrating a configuration of a seat belt retractor in an embodiment according to 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 seat belt retractor including, for example, a spool 4, a rotating body 52, a first EA mechanism 53, a locking mechanism 6, a power transmission mechanism 21, a second EA mechanism 54, and a stopper 57.

[0023] The spool 4 is a member that is rotatably supported by a frame (not shown) and that winds up the seat belt 104 so that the seat belt 104 can be withdrawn.

[0024] 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 .

[0025] The locking mechanism 6 allows rotation of the spool 4 when not activated, and prevents rotation of the spool 4 in the unwinding direction of the seat belt 104 when activated. The locking mechanism 6 prevents rotation of the spool 4 in the unwinding direction of the seat belt 104 by locking the first EA mechanism 53 when activated.

[0026] The first EA mechanism 53 is deformed by rotation of the spool 4 in the unwinding direction of the seat belt 104 and by the prevention of rotation by the locking mechanism 6. The first EA mechanism 53 is an example of a first energy absorbing 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 rotating body 52 so as not to rotate relative to the occupant. When the spool 4 and the rotating body 52 rotate in the unwinding direction of the seat belt while locked by the locking mechanism 6, the first EA mechanism 53 is deformed.

[0027] The power transmission mechanism 21 has, for example, a motor 12 that rotates a rotating body 52. ​​The power transmission mechanism 21 adds a second load (hereinafter also referred to as an assist load AN) generated by the output of the motor 12 to a first load (hereinafter also referred to as a base load BN) generated by the deformation of the first EA mechanism 53. The number of the speed reduction mechanisms 51 that reduce the speed of the rotation of the output shaft of the motor 12 and transmit it may be one or more. One speed reduction mechanism 51 is shown in FIG. 2. The rotating body 52 may be equipped with a speed reduction mechanism. The base load BN and the assist load AN contribute to a load (EA load) that limits the withdrawal of the seat belt 104 in an emergency. The retractor 1 reduces the load acting on the seat belt 104 by limiting the withdrawal of the seat belt 104 by the EA load in an emergency.

[0028] The second EA mechanism 54 is connected to the spool 4 and the rotating body 52 so as to be unable to rotate relative to each other. The second EA mechanism 54 limits an increase in the EA load by deforming itself. The second EA mechanism 54 deforms when the load acting on the second EA mechanism 54 reaches a set value as a result of the spool 4 rotating in the unwinding direction of the seat belt 104. The second EA mechanism 54 is an example of a second energy absorption mechanism that absorbs and alleviates the energy of the occupant by limiting the load acting on the seat belt.

[0029] The stopper 57 is a member that allows the rotation of the rotating body 52 when not in operation, and that locks the rotating body 52 when in operation. The stopper 57 locks the rotating body 52, thereby preventing the rotating body 52 from rotating.

[0030] Next, an example of the operation in an emergency such as a vehicle collision will be described.

[0031] In an emergency, the seat belt 104 is tightly wound around the spool 4 by rotating the spool 4 in the belt winding direction by the operation of at least one of the pretensioner 8 and the motor 12. The output of the motor 12 is transmitted to the rotor 52 via the speed reducer 51 and the clutch 25, causing the rotor 52 to rotate, and the spool 4 rotates in the belt winding direction in conjunction with the rotation of the rotor 52. Thereafter, the seat belt 104 is attempted to be withdrawn from the spool 4 by the occupant moving forward due to inertia. At this time, the first EA mechanism 53 is locked by the operation of the lock mechanism 6, so that the rotation of the rotor 52, which is connected to the first EA mechanism 53 so as not to rotate relative to the rotor 52, is prevented, and the rotation of the spool 4 in the belt withdrawing direction is prevented by preventing the rotation of the rotor 52. However, since the spool 4 tends to rotate together with the rotor 52 in the belt-withdrawing direction, the first EA mechanism 53 is deformed due to the rotation of the spool 4 and rotor 52 in the seat belt 104-withdrawing direction and the prevention of rotation by the lock mechanism 6. The EA load generated by the deformation of the first EA mechanism 53 limits the withdrawal of the seat belt 104 from the spool 4, so the energy of the occupant is absorbed and mitigated by the deformation of the first EA mechanism 53.

[0032] 3 is a diagram illustrating an example of a change in EA load with respect to the stroke of the spool 4. The horizontal axis represents the amount of relative rotation (stroke) of the spool 4 in the belt-retracting direction after the locking mechanism 6 is activated, and the vertical axis represents the EA load (also referred to as the "limit load LN") generated by the retractor 1.

[0033] 3, the power transmission mechanism 21 generates a limited load LN by adding an assist load AN generated by the output of the motor 12 to a base load BN generated by the deformation of the first EA mechanism 53. The limited load LN is approximately equal to the sum of the base load BN and the assist load AN.

[0034] When the limit load LN has not reached the upper limit load Lb, the assist load AN is added to the base load BN as is. The upper limit load Lb is determined by the second limit load N2 by the second EA mechanism 54. The first limit load N1 is the maximum load that can be generated by the deformation of the first EA mechanism 53 when the transmission of force between the motor 12 and the rotor 52 is interrupted by turning off the clutch 25 or the like. The second limit load N2 is the maximum load that can be generated by the deformation of the second EA mechanism 54. 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 an excessive load can be prevented from acting on the seat belt 104.

[0035] Furthermore, the retractor 1 includes a control unit 10 (see FIG. 2) that adjusts the assist load AN by controlling the motor 12, so that the limited load LN can be flexibly adjusted within a range equal to or less than the upper limit load Lb.

[0036] For example, the control unit 10 can adjust the rising speed of the limited load LN as shown by waveforms d and e in Fig. 3 by adjusting the rising speed of the assist load AN by controlling the motor 12. The waveform d shows a case where the motor 12 is controlled so as to increase the rising speed of the assist load AN, and the waveform e shows a case where the motor 12 is controlled so as to decrease the rising speed of the assist load AN.

[0037] Also, 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. This allows the limited load LN to be increased or decreased within a range from the first limited load N1 to the upper limit load Lb, as shown in the waveforms f, g, and h of FIG. 3. Also, the control unit 10 can adjust the limited load LN to the first limited load N1 by stopping the motor 12 and setting the assist load AN to zero. Also, the control unit 10 can adjust the limited load LN to be lower than the first limited load N1 by controlling the motor 12 so that a negative assist load AN is added to the base load BN. For example, the control unit 10 can increase or decrease the limited load LN within a range lower than the first limited load N1 by increasing or decreasing the negative assist load AN added to the base load BN by controlling the motor 12.

[0038] In this way, the control unit 10 can generate a flexible limited 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 limited load LN according to the collision conditions and the physique of the occupant.

[0039] In addition, when the transmission of force between the motor 12 and the rotating body 52 is interrupted due to the clutch 25 being off or the power transmission mechanism 21 failing, the assist load AN is not added to the base load BN. Even in such a case, when the rotating body 52 is locked by the stopper 57, the limit load LN can be limited to the upper limit load Lb as shown in 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 rotating body 52 is locked by the stopper 57, the limit load LN can be limited to the upper limit load Lb as shown in the waveforms j and k. That is, in such a case, the load acting on the seat belt 104 can be limited to 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 the rotation amount preset by the stopper 57 as the rotation amount at which the stopper 57 starts locking the rotating body 52.

[0040] In this way, the retractor 1 allows the EA load to be flexibly adjusted.

[0041] Next, the configuration shown in FIG. 2 will be described in more detail.

[0042] The motor 12 and the spool 4 are preferably connected to each other via the 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 can be accurately limited to the second limit load N2 or less by the second EA mechanism 54.

[0043] The reduction mechanism 51 reduces the rotation speed of the output shaft 12 a of the motor 12 and transmits it to the rotor 52 .

[0044] In addition, the power transmission mechanism 21 preferably has a clutch 25 that blocks the transmission of force from the rotating body 52 to the motor 12 and allows the transmission of force from the motor 12 to the rotating body 52. ​​By providing the clutch 25 that blocks the transmission of force from the rotating body 52 to the motor 12, for example, it is possible to prevent a large winding torque of the seat belt 104 by the pretensioner 8 at the time of a collision from being transmitted to the motor 12 via the rotating body 52 that rotates together with the spool 4. In addition, if the rotating body 52 and the output shaft of the motor 12 are connected via the reduction mechanism 51, when the occupant operates to withdraw the seat belt 104 from the retractor 1 or to wind it up into the retractor 1, the load of the motor 12 is transmitted to the occupant operating the seat belt 104. As a result, the occupant cannot smoothly withdraw or wind up the seat belt 104, which may cause discomfort to the occupant. In contrast, the clutch 25 is a one-way clutch that blocks the transmission of rotational force from the spool 4 to the motor 12 via the rotor 52, and transmits the rotational force from the motor 12 to the spool 4 via the rotor 52. Therefore, since the transmission of rotational force from the spool 4 to the motor 12 via the rotor 52 is blocked by the clutch 25, the occupant can smoothly pull out the seat belt 104 from the retractor 1 or have the seat belt 104 retracted by the retractor 1.

[0045] The clutch 25 blocks the transmission of force from the rotating body 52 to the output shaft 12a when the rotation of the output shaft 12a of the motor 12 is stopped, and allows the transmission of force from the output shaft 12a to the rotating body 52 when the output shaft 12a is rotating. This allows the control unit 10 to turn on the clutch 25 (allowing the transmission of force from the output shaft 12a to the rotating body 52) by operating the motor 12 to rotate the output shaft 12a. On the other hand, the control unit 10 can turn off the clutch 25 (blocking the transmission of force from the rotating body 52 to the output shaft 12a) by stopping the motor 12 to stop the rotation of the output shaft 12a. In other words, the control unit 10 can turn on the clutch 25 in synchronization with the operation of applying the assist load AN.

[0046] Next, a specific configuration of the retractor 1 will be described.

[0047] 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 view showing a cut surface of the seat belt retractor in the first embodiment in the direction of the arrow AA (see Fig. 6). Fig. 8 is an exploded perspective view of the seat belt retractor in the first embodiment.

[0048] The retractor 1A shown in Figs. 4 to 8 is an example of a seat belt retractor, and is a specific example of the retractor 1 shown in Fig. 2. 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 deformation of a torsion bar 7 provided between the rotating body 52 and the locking mechanism 6. The second EA mechanism 54A limits an increase in the limited load LN by deformation of a 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. Hereinafter, the configuration of the retractor 1A will be described with reference to Figs. 4 to 8.

[0049] The retractor 1A includes a frame 2, a spool 4, a rotating body 52, a first EA mechanism 53A, a vehicle sensor 5, a locking mechanism 6, a power transmission mechanism 21A, a return spring 65, a second EA mechanism 54A, and a stopper 57.

[0050] The frame 2 is a housing that rotatably houses the spool 4 and forms the framework of the retractor 1A. The frame 2 has, for example, a pair of opposing side portions 2b, 2c and a back portion 2a that connects the side portions 2b, 2c. A lock mechanism 6 is disposed on the outer side of the side portion 2b (i.e., the side opposite the spool 4 side with respect to the side portion 2b). Each of the pair of side portions 2b, 2c has a circular (including approximately circular) opening.

[0051] The spool 4 is a winding member that is supported concentrically (including approximately concentrically) with each opening of the pair of side surface portions 2b, 2c of the frame 2 and rotatably, and that winds up the seat belt 104.

[0052] 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 the 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 it is locked by the stopper 57, it is fitted into the inner wall of the cylindrical spool 4 with a fitting force that allows the spool 4 to rotate relative to the rotating body 52. ​​The rotating body 52 is a cylindrical shaft gear having a flange on which external teeth 52a are formed.

[0053] The first EA mechanism 53A has a torsion bar 7 connected to the rotating body 52 so as not to rotate relative to the rotating body 52. ​​The torsion bar 7 is an example of a first torsion bar. The torsion bar 7 has a first connecting portion 15 connected to the rotating body 52 so as not to rotate relative to the rotating body 52, and a second connecting portion 16 locked by the locking mechanism 6. These connecting portions are provided at positions spaced apart from each other in the axial direction. In this example, the first connecting portion 15 is connected to the inner wall of the cylindrical rotating body 52 so as not to rotate relative to the rotating body 52, 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 relative to the rotating body 52.

[0054] The torsion bar 7 has a tip portion 7a that protrudes in the axial direction from the second connecting portion 16. The tip portion 7a penetrates the locking base 17 and is rotatably supported by a retainer 61 via a bearing cap 62. The retainer 61 is fixed to the side surface portion 2b of the frame 2.

[0055] The vehicle sensor 5 is an example of a detection mechanism that detects changes in vehicle behavior (specifically, sudden changes in the acceleration / deceleration and inclination of the vehicle that occur with changes in the vehicle behavior). The vehicle sensor 5 has, for example, a sphere that moves with the vehicle deceleration that occurs in an emergency, and a locking claw that is actuated by the movement of the sphere.

[0056] The locking mechanism 6 performs a locking operation to lock the rotation of the spool 4 in the unwinding direction of the seat belt 104. The locking mechanism 6 includes a locking gear 14 and a locking base 17. The locking gear 14 is fitted to a tip end 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 end 7a may be a separate member such as a shaft axially connected to the torsion bar 7, or may be a part of the torsion bar 7 itself. The locking base 17 is supported by a second connecting portion 16 described later so as to be integrally rotatable, and holds the pawl so as to be swingable. The locking base 17 is an example of a locking member, which normally rotates together with the spool 4 and the rotating body 52, and when activated, prevents the rotation of the spool 4 in the unwinding direction of the seat belt 104. Ratchet teeth 14a are formed on the outer periphery of the locking gear 14.

[0057] The lock gear 14 normally rotates together with the torsion bar 7. On the other hand, in the above-mentioned emergency, the sphere of the vehicle sensor 5 is activated and the locking claw engages with the ratchet teeth 14a. This prevents (locks) the lock gear 14 from rotating in the withdrawing direction of the seat belt 104. When the rotation of the lock gear 14 is locked, relative rotation occurs between the locking base 17 and the lock gear 14, causing the pawl provided on the locking base 17 to rotate, and the rotated pawl engages with the internal teeth 2ba provided on the side surface portion 2b. This stops the rotation of the locking base 17, and also prevents the spool 4 and the rotor 52 from rotating in the withdrawing direction of the seat belt 104.

[0058] The power transmission mechanism 21A is an example of the power transmission mechanism 21 shown in Fig. 2. The power transmission mechanism 21A includes a motor 12, a retainer 28, a reduction gear mechanism 51, a gear case 29, and a clutch 25.

[0059] The motor 12 generates power to rotate the spool 4 and the rotor 52. The motor 12 is fixed to a retainer .

[0060] 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.

[0061] The reduction gear mechanism 51 has a motor gear 20 and a connecting gear 22, and transmits the rotation of the output shaft 12a of the motor 12 at a reduced speed.

[0062] The motor gear 20 is attached to be rotatable integrally with 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.

[0063] The connect gear 22 has external teeth 22a that constantly mesh with the external teeth 20a of the motor gear 20, and a shaft hole 22b into which a boss protruding from a 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 about a shaft protruding from the gear case 29.

[0064] The gear case 29 has a boss that rotatably holds the idle gear 26 and a boss that rotatably holds the clutch gear 24 .

[0065] The idle gear 26 has external teeth 26a that constantly mesh 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.

[0066] The clutch 25 has a drive gear 23, a clutch gear 24 supported rotatably coaxially with the drive gear 23, a pair of clutch pawls 41 provided on the drive gear 23, and a pair of clutch springs 42 that bias the pair of clutch pawls 41.

[0067] The drive gear 23 receives the force of the motor 12 via the motor gear 20 and the connect gear 22 and rotates in accordance with the rotation of the output shaft 12 a of the motor 12 .

[0068] The clutch gear 24 is rotatably supported coaxially with the drive gear 23 and is connected to the rotor 52 via the idle gear 26 .

[0069] When the drive gear 23 is stopped from rotating, the clutch pawl 41 is held in a position where it does not engage with the internal ratchet teeth of the clutch gear 24 due to the biasing force of the clutch spring 42 .

[0070] On the other hand, when the output shaft 12a of the motor 12 is rotating, the drive gear 23 also rotates due to the rotation of the motor gear 20 and the connect gear 22. When the drive gear 23 rotates, a centrifugal force acts on the clutch pawl 41.

[0071] When the drive gear 23 rotates in a direction corresponding to the winding direction of the seat belt 104 due to the rotation of the output shaft 12a, the clutch pawl 41 moves due to the centrifugal force while resisting the biasing force of the clutch spring 42. The clutch pawl 41 moved by the centrifugal force engages with the internal ratchet teeth of the clutch gear 24. Conversely, when the drive gear 23 rotates in a direction corresponding to the unwinding direction of the seat belt 104 due to the rotation of the output shaft 12a, the movement of the clutch pawl 41 in a direction approaching the internal ratchet teeth of the clutch gear 24 is restricted by the stopper of the drive gear 23 even if the centrifugal force acts. Therefore, the clutch pawl 41 is prevented from engaging with the internal ratchet teeth.

[0072] Therefore, in a state in which the drive gear 23 rotates in a direction corresponding to the winding direction of the seat belt 104 by the rotation of the output shaft 12a, the clutch pawl 41 is maintained in an engaged state with the ratchet internal teeth. In this engaged state, the rotational power of the output shaft 12a is transmitted through the motor gear 20, the connect gear 22, the clutch gear 24, the idle gear 26, and the rotor 52. In this engaged state, the rotational force of the output shaft 12a is transmitted to the spool 4, so that the seat belt 104 is wound onto the spool 4.

[0073] On the other hand, in a state where the drive gear 23 rotates in a direction corresponding to the unwinding direction of the seat belt 104 by the rotation of the output shaft 12a, the clutch pawl 41 is maintained in a state of not engaging with the ratchet internal teeth. In addition, in a state where the rotation of the output shaft 12a is stopped, the rotation of the drive gear 23 is stopped, so that the clutch pawl 41 is maintained in a state of not engaging 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, but is not transmitted to the drive gear 23. Therefore, in these disengaged states, the rotational force of the rotating shaft of the spool 4 is not transmitted to the output shaft 12a. In other words, the transmission of the rotational force from the rotating shaft of the spool 4 to the output shaft 12a is interrupted.

[0074] In this way, the clutch 25 is a one-way clutch that blocks the transmission of rotational force from the rotating body 52 to the motor 12 and transmits the rotational force from the motor 12 to the rotating body 52. ​​Therefore, the transmission of rotational force from the spool 4 to the motor 12 is blocked by the clutch 25, so that the occupant 111 can smoothly pull out the seat belt 104 from the retractor 1 or have the retractor 1 retract the seat belt 104.

[0075] The return spring 65 biases the spool 4 so that the spool 4 rotates in the direction of winding up the seat belt 104. The return spring 65 is housed in a spring case 66 fixed to the side surface portion 2c.

[0076] The second EA mechanism 54A has a torsion bar 30 connected to the rotating body 52 so as not to rotate relative to the rotating body 52. ​​The torsion bar 30 is an example of a second torsion bar. The torsion bar 30 has a third connecting portion 18 connected to the spool 4 so as not to rotate relative to the rotating body 52, and a fourth connecting portion 19 connected to the rotating body 52 so as not to rotate relative to the rotating body 52. ​​These connecting portions are provided at positions spaced apart 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 relative to the rotating body 52, and the fourth connecting portion 19 is connected to the inner wall of the cylindrical rotating body 52 so as not to rotate relative to the rotating body 52.

[0077] The torsion bar 30 has a tip portion 30a that protrudes in the axial direction from the third connecting portion 18. The tip portion 30a is rotatably supported by a spring case 66 via a bush nut 64. The torsion bar 30 has a diameter larger than the diameter of the torsion bar 7. The torsion bar 30 is disposed coaxially with the torsion bar 7.

[0078] The stopper 57 is an annular member that allows the rotation of the rotor 52 when not in operation and locks the rotor 52 when in operation. The stopper 57 is disposed inside the cylindrical rotor 52 and is connected to the inner wall of the rotor 52 so as not to rotate relative to the rotor 52.

[0079] 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 a part of the internal structure of the retractor 1A. Fig. 10 is a cross-sectional view taken along the line BB (see Fig. 9) showing the state before the stopper 57 is actuated. Fig. 11 is a cross-sectional view taken along the line BB (see Fig. 9) showing the state after the stopper 57 is actuated.

[0080] 10, when the lock mechanism 6 of the first EA mechanism 53A is activated, the rotation of the locking base 17 is locked, and the torsion bar 7 is locked at the second connecting portion 16. As a result, the spool 4 rotates in the unwinding direction of the seat belt 104, and the rotating body 52 rotates together with the spool 4. The torsion bar 7 starts to twist and deform because it is connected to the rotating body 52 at the first connecting portion 15 by press-fitting or the like so as not to rotate relative to the rotating body 52.

[0081] 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 deformation amount. The stopper 57 may operate to lock the rotating body 52 when its own rotation reaches a set rotation amount. With the rotating body 52 locked by the stopper 57, the torsion bar 30 of the second EA mechanism 54A starts to be torsionally deformed when the spool 4 rotates in the withdrawing direction of the seat belt 104. 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 rotate relative to the rotating body 52. ​​The torsion bar 30 starts to be torsionally deformed when the load acting on it reaches a set value.

[0082] 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 rotating body 52 so as not to rotate relative to the rotating body 52, the rotation of the rotating body 52 is locked when the rotation of the stopper 57 stops.

[0083] In this example, the stopper 57 moves along the rotation axis 67 while rotating around the rotation axis 67 of the rotating body 52. ​​The rotating body 52 is disposed coaxially with the spool 4. A male thread is formed on the cylindrical portion 17a of the locking base 17, and a female thread is formed on the inner surface of the stopper 57. This allows the stopper 57 to move along the axial direction (rotation axis 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 rotation and movement of the stopper 57 stops.

[0084] By locking the rotor 52, only the spool 4 rotates, and the torsion bar 30 of the second EA mechanism 54A begins to undergo torsional deformation.

[0085] In this manner, the torsion bar 30 of the second EA mechanism 54A is deformed when the spool 4 rotates in the unwinding direction with the rotor 52 locked by the stopper 57 and the load acting on the torsion bar 30 reaches the set value. As a result, the load acting on the seat belt 104 is limited by the EA load caused by 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 prevented from becoming excessive. For example, when the torsion bar 7 of the first EA mechanism 53A is deformed and a force is being transmitted from the motor 12 to the rotor 52, the torsion bar 30 of the second EA mechanism 54A deforms when the load acting on the torsion bar 30 of the second EA mechanism 54A reaches the set value.

[0086] According to the retractor 1A having the above-described structure, the torsion bar 30 of the second EA mechanism 54A deforms even if the load acting on it reaches the set value when the spool 4 rotates in the pull-out direction with the rotor 52 not locked by the stopper 57. For example, the torsion bar 30 of the second EA mechanism 54A deforms even if the load generated by the deformation of the torsion bar 7 of the first EA mechanism 53A and the output of the motor 12 reaches the set value with the rotor 52 not locked by the stopper 57.

[0087] 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. When the clutch 25 is activated, 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 activated, the load generated by the output of the motor 12 is not transmitted to the rotor 52 and the spool 4.

[0088] Furthermore, according to the retractor 1A, even if the EA load by the motor 12 is not generated due to some abnormality after the EA load by the first EA mechanism 53A is ensured, the EA load by the second EA mechanism 54A can be generated by operating the stopper 57. This makes it possible to more appropriately restrain the occupant even if the EA load by the motor 12 is not generated during a collision with relatively high collision energy, for example.

[0089] The retractor 1A may include a spacer 63. 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 17a of the locking base 17. Therefore, there is a risk of rattling occurring between the stopper 57 and the rotating body 52. ​​Thus, by filling this gap with, for example, a resin spacer 63, it is possible to prevent rattling from occurring.

[0090] Although the embodiments have been described above, the technology of the present disclosure is not limited to the above-described embodiments. Various modifications and improvements, such as combinations with or substitutions for part or all of other embodiments, are possible. [Explanation of symbols]

[0091] 1,1A Retractor 2 Frames 4 Spools 5 Vehicle Sensors 6 Locking mechanism 7 Torsion bar 8 Pretensioner 10 Control section 12 Motor 14. Lock Gear 15 1st connection part 16 2nd connection part 17 Rocking Base 18 Third connection part 19 4th connection part 20 Motor Gear 21 Power transmission mechanism 22 Connect Gear 23 Drive gear 24 Clutch gear 25 Clutch 26 Idol Gear 28 Retainer 29 Gear Case 30 Torsion bar 41 Clutch pawl 51 Reduction mechanism 52 Rotating Body 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 Rotational Axis

Claims

1. A spool for winding the seat belt; A rotating body rotatable together with the spool; a first energy absorbing mechanism including a first connecting portion connected to the rotating body so as not to rotate relative to the rotating body and a second connecting portion provided at a location spaced apart from the first connecting portion; a lock mechanism having a locking base connected to the second connecting portion so as not to rotate relative to the second connecting portion; A motor that rotates the rotating body; a second energy absorbing mechanism including a third connecting portion connected to the spool so as not to rotate relative to the rotor and a fourth connecting portion connected to the rotor so as not to rotate relative to the rotor, the third connecting portion and the fourth connecting portion being provided at positions spaced apart from each other; A stopper, the first energy absorbing mechanism is deformed when the spool and the rotating body rotate in the seat belt withdrawing direction with the rotation of the locking base locked, The second energy absorbing mechanism is deformed when the spool rotates in the unwinding direction with the rotation of the rotating body locked by the stopper.

2. 2. The seat belt retractor according to claim 1, wherein the second energy absorption mechanism is deformed when the spool rotates in the unwinding direction with the rotation of the rotating body locked by the stopper and a load acting on the second energy absorption mechanism reaches a set value.

3. 3. The seat belt retractor according to claim 2, wherein the second energy absorption mechanism is deformed when the spool rotates in the unwinding direction while the rotation of the rotating body is not locked by the stopper, and the load acting on the second energy absorption mechanism reaches the set value.

4. 4. The seat belt retractor according to claim 1, wherein the stopper is operable to lock the rotation of the rotating body when the deformation of the first energy absorbing mechanism reaches a predetermined deformation amount.

5. 5. The seat belt retractor according to claim 1, wherein the stopper operates depending on the rotation of the rotating body.

6. 6. The seat belt retractor according to claim 5, wherein the stopper rotates depending on the rotation of the rotating body.

7. 4. The seat belt retractor according to claim 1, wherein the stopper operates to lock the rotation of the rotating body when the rotation of the stopper itself reaches a set rotation amount.

8. The rotation of the stopper stops when the set rotation amount is reached, 8. The seat belt retractor according to claim 7, wherein the rotation of the rotating body is locked by stopping the rotation of the stopper.

9. 9. The seat belt retractor according to claim 6, wherein the stopper moves along the rotation shaft of the rotating body while rotating about the rotation shaft.

10. The stopper is a member that rotates around a rotation axis of the rotating body and moves along the rotation axis, The rotation and movement of the stopper stops when it reaches the locking mechanism, 4. The seat belt retractor according to claim 1, wherein the rotation of the rotating body is locked by stopping the rotation and movement of the stopper.

11. The seat belt retractor according to claim 1 , wherein the rotor is disposed coaxially with the spool.

12. The seat belt retractor according to any one of claims 1 to 11, wherein the rotating body rotates together with the spool until rotation of the rotating body is locked by the stopper.

13. The motor rotates the rotor to rotate the spool in a seat belt winding direction, 13. The seat belt retractor according to claim 1, further comprising a clutch that blocks transmission of force from the rotating body to the motor and allows transmission of force from the motor to the rotating body.

14. 14. The seat belt retractor according to claim 1, wherein the first energy absorbing mechanism includes a first torsion bar having the first connecting portion and the second connecting portion.

15. A seat belt retractor as described in claim 14, wherein the first connecting portion and the second connecting portion are spaced apart from each other in the axial direction of the first torsion bar.

16. 16. The seat belt retractor according to claim 14 or 15, wherein the second energy absorbing mechanism includes a second torsion bar having the third connecting portion and the fourth connecting portion.

17. 17. The seat belt retractor according to claim 16, wherein the second torsion bar is disposed coaxially with the first torsion bar.

18. A seat belt retractor as described in claim 16 or 17, wherein the third connecting portion and the fourth connecting portion are spaced apart from each other in the axial direction of the second torsion bar.

19. 19. The seat belt retractor according to claim 1, further comprising a control unit that controls the motor.

20. A seat belt device comprising: a seat belt retractor according to any one of claims 1 to 19; the seat belt; a tongue attached to the seat belt; and a buckle with which the tongue is releasably engaged.

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