Retractor and seat belt device

Abstract

To provide a retractor and a seat belt device capable of freely controlling an energy absorbing load regardless of a set load of a torsion bar.SOLUTION: A retractor 1 includes: a spool 2 for winding up a webbing configured to restrain an occupant; a pretensioner 3 configured to, in an emergency, wind up the webbing to remove slack; a lock mechanism 4 configured to, in the emergency, restrict rotation of the spool 2 in a webbing pull-out direction; an energy absorbing mechanism 5 configured to, when the lock mechanism 4 is operated, absorb kinetic energy of the occupant by limiting a load applied to the webbing; a torque transmission mechanism 6 configured to transmit torque of a motor 61 to a spool 2 to rotate the spool; and a lock limiting mechanism 7 configured to, after operation of the lock mechanism 4 restricts the rotation of the spool 2, release the restriction of the rotation of the spool 2 of a lock mechanism 4.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a retractor and a seat belt device, and more particularly to a retractor and a seat belt device characterized by the setting of an energy absorption load for an occupant in the event of a vehicle collision. [Background technology]

[0002] In vehicles such as automobiles, a seat belt device for restraining an occupant is generally provided on a seat having a seat portion on which the occupant sits and a backrest portion located behind the occupant. Such a seat belt device generally includes a webbing for restraining the occupant, a retractor for winding up the webbing, a guide anchor provided on the vehicle body side for guiding the webbing, a belt anchor for fixing the webbing to the vehicle body side, a buckle provided on the side of the seat, and a tongue provided on the webbing, and the occupant is restrained by the webbing by fitting the tongue into the buckle.

[0003] Here, it is becoming common for retractors to have a pretensioner that removes slack in the webbing in an emergency such as a vehicle collision. Also, retractors often have an energy absorption mechanism for reducing the load caused by the forward movement of the occupant after the pretensioner is activated. Such an energy absorption mechanism can effectively reduce the load on the occupant by cooperating with other safety devices such as an airbag device.

[0004] The energy absorption mechanism often uses a torsion bar that is configured to be torsionally deformable in the webbing pull-out direction under a predetermined load when an occupant is restrained during a vehicle collision. For example, Patent Document 1 discloses a configuration in which a motor is added that applies a torque to rotate a spool in the webbing pull-in or pull-out direction, and the motor torque load is added to the set load of the torsion bar by rotating the motor forward, and the motor torque load is subtracted from the set load of the torsion bar by rotating the motor reversely, thereby reducing the belt load. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-97359 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the invention described in Patent Document 1, the torque load of the motor is controlled with the rotation of one side of the spool locked by a locking mechanism, so the load can only be controlled by either adding to or subtracting from the set load of the torsion bar, which means there is a limit to the control range of the energy absorption load (belt load).

[0007] The present invention has been devised in view of the above problems, and has an object to provide a retractor and a seat belt device that can freely control the energy absorption load without being influenced by the set load of the torsion bar. [Means for solving the problem]

[0008] According to the present invention, there is provided a retractor including a spool that winds up webbing to restrain an occupant, a locking mechanism that restricts rotation of the spool in the webbing-pulling direction in an emergency, an energy absorption mechanism that absorbs the kinetic energy of the occupant by limiting the load applied to the webbing when the locking mechanism is activated, and a torque transmission mechanism that transmits the torque of a motor to the spool to rotate it, wherein the retractor is further provided with a lock limiting mechanism that prevents the locking mechanism from operating, thereby maintaining a state in which the restriction on the rotation of the spool is released, and the lock limiting mechanism is configured to prevent the locking mechanism from operating after the locking mechanism has operated to restrict the rotation of the spool, and then to release the operating state of the locking mechanism by the torque transmission mechanism so that the locking mechanism does not operate.

[0009] The locking mechanism may include a locking gear arranged coaxially with the spool so as to be rotatable relative to the spool, a pawl that restricts rotation of the spool when the locking gear rotates relative to the spool, a vehicle sensor that detects acceleration or inclination of a vehicle body and restricts rotation of the locking gear, a flywheel that detects a sudden pull-out of the webbing and rotates, and a gearing arranged coaxially with the spool and capable of engaging with the flywheel when it is activated to restrict rotation of the spool, and the lock limiting mechanism may be configured to maintain a released state of the rotation restriction state of the spool based on the operation of the vehicle sensor, and to maintain a released state of the rotation restriction state of the spool based on the operation of the flywheel.

[0010] The lock limiting mechanism may be configured to restrict rotation of the gear ring when not in operation, and to release the restricted state of the gear ring to allow rotation of the gear ring when in operation.

[0011] The lock limiting mechanism may be configured to maintain a disengaged state between the vehicle sensor and the lock gear when activated.

[0012] The lock limiting mechanism may include a lever having a first restraining portion that restrains the vehicle sensor from engaging with the lock gear when not in operation and a second restraining portion that restrains the gear ring from rotating, and a drive device that operates the lever, and is configured to operate the lever when in operation to release the restraint of the gear ring by the first restraining portion and restrain the vehicle sensor.

[0013] The vehicle sensor may have an actuator engageable with the lock gear, and the first restraint portion may be configured to press down the actuator and move it away from the lock gear when activated.

[0014] The gear ring may have a plurality of protrusions formed on its outer peripheral surface, and the second restraint portion may be configured to engage with one of the protrusions when inactive and to move away from the protrusion when active.

[0015] The lock limiting mechanism may be configured to rotate the lever to return the lock limiting mechanism to a non-operating state when an abnormality is detected.

[0016] The energy absorbing mechanism may be a torsion bar disposed on a central axis of the spool, having a first end fixed to the locking mechanism and a second end connected to the spool.

[0017] According to the present invention, there is also provided a seat belt device comprising a retractor having any one of the above-described configurations. Effect of the Invention

[0018] According to the retractor and seat belt device of the present invention described above, by disposing a lock limiting mechanism that prevents the locking mechanism from operating and keeps the restriction on the rotation of the spool released, after the locking mechanism is operated to restrict the rotation of the spool, the locking mechanism is released from its operating state by the torque transmission mechanism, and then the locking mechanism is prevented from operating by the lock limiting mechanism. Therefore, according to the present invention, the energy absorption load can be freely controlled without being influenced by the set load of the torsion bar. [Brief description of the drawings]

[0019] [Figure 1] FIG. 2 is a parts exploded view showing a retractor according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view showing an assembled state of the retractor shown in FIG. [Diagram 3] 4A and 4B are enlarged views showing the lever of the lock limiting mechanism, in which (A) is a perspective view showing the front side, and (B) is a perspective view showing the back side. [Figure 4] FIG. 5 is an operation flow diagram of the lock limiting mechanism. [Diagram 5] 5A and 5B are explanatory diagrams showing the relationship between the lock restriction mechanism and the vehicle sensor before the lock mechanism and the lock restriction mechanism are activated, where FIG. 5A is a front view and FIG. [Figure 6] 5A and 5B are explanatory diagrams showing the relationship between the lock limiting mechanism and the vehicle sensor after the lock mechanism is activated (before the lock limiting mechanism is activated), where (A) is a front view and (B) is a rear view. [Figure 7] 5A and 5B are explanatory diagrams showing the relationship between the lock limiting mechanism and the vehicle sensor after the lock limiting mechanism is activated, where (A) is a front view and (B) is a rear view. [Figure 8] 5A and 5B are explanatory diagrams showing the relationship between the lock limiting mechanism and the gearing, in which (A) shows the state before the lock limiting mechanism is activated, and (B) shows the state after the lock limiting mechanism is activated. [Figure 9] 1A and 1B are explanatory diagrams showing an example of a method for controlling an energy absorption load, in which (A) shows an example of a single load setting, and (B) shows an example of a multiple load setting. [Figure 10] 1 is a perspective view showing a seat belt device according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to Figs. 1 to 10. Fig. 1 is a parts exploded view showing a retractor according to one embodiment of the present invention. Fig. 2 is a perspective view showing the assembled state of the retractor shown in Fig. 1. Fig. 3 is an enlarged view showing a lever of a lock limiting mechanism, (A) being a perspective view showing the front side, and (B) being a perspective view showing the back side. For convenience of explanation, the webbing is omitted in Figs. 1 and 2.

[0021] As shown in Figures 1 and 2, a retractor 1 according to one embodiment of the present invention includes a spool 2 that winds up a webbing for restraining an occupant, a pretensioner 3 that winds up the webbing to remove slack in an emergency, a locking mechanism 4 that restricts rotation of the spool 2 in the webbing withdrawal direction in an emergency, an energy absorbing mechanism 5 that absorbs the kinetic energy of the occupant by limiting the load applied to the webbing when the locking mechanism 4 is activated, a torque transmission mechanism 6 that transmits the torque of a motor 61 to the spool 2 to rotate it, a lock limiting mechanism 7 that prevents the locking mechanism 4 from operating after the locking mechanism 4 is activated to restrict the rotation of the spool 2, thereby maintaining a state in which the restriction on the rotation of the spool 2 is released, and a spring unit 8 that biases the spool 2 in the webbing winding direction.

[0022] The spool 2 is a winding drum that winds up the webbing, and is rotatably housed within a base frame 11 that forms the framework of the retractor 1. In addition, for example, a pretensioner 3 and a locking mechanism 4 are disposed on a first end 21 side of the spool 2, and a torque transmission mechanism 6 and a spring unit 8 are disposed on a second end 22 side. Note that the arrangement of these components is merely one example, and is not limited to the arrangement shown in the figure.

[0023] The base frame 11 is, for example, a frame structure having a substantially rectangular U-shaped cross section, and a pair of wall members constituting the side surface are formed at both ends of a wall member constituting the back surface. Of the pair of wall members constituting the side surface, a first opening 11a is formed in the wall member on the first end 21 side, and a second opening 11b is formed in the wall member on the second end 22 side. In addition, internal teeth 11c are formed on the inner peripheral surface of the first opening 11a with which the pawl 43 engages when the lock mechanism 4 is activated. In addition, a tie plate 11d constituting the front surface may be connected to the tip of the pair of wall members constituting the side surface.

[0024] The pretensioner 3 includes a paddle gear (not shown) connected to the locking base 41, and a power transmission device 31 that transmits power to the paddle gear in an emergency. The pretensioner 3 is disposed, for example, inside a wall member of the base frame 11 having the first opening 11a. Note that the configuration of the pretensioner 3 is merely an example, and is not limited to the configuration shown in the figure. For example, the pretensioner 3 may be disposed outside the wall member of the base frame 11.

[0025] The power transmission device 31 includes, for example, a power transmission member (not shown) that transmits power to a paddle gear, a cylindrical guide member 32 that guides the power transmission member to the paddle gear, a gas generator 33 that supplies working gas to the inside of the guide member 32, and a cover member 34 that forms a passage for the power transmission member on the outer periphery of the paddle gear.

[0026] In the event of an emergency such as a vehicle collision, a working gas is supplied from a gas generator 33 into the guide member 32, and the power transmission member moves along the guide member 32. The power transmission member released from the guide member 32 collides with the engaging teeth of the paddle gear, causing the paddle gear to rotate. This rotation of the paddle gear rotates the spool 2 to wind up the webbing, removing slack in the webbing and restraining the occupant in the seat.

[0027] The locking mechanism 4 includes, for example, a locking base 41 connected to the spool 2 via an energy absorbing mechanism 5 (torsion bar 51), a locking gear 42 arranged coaxially adjacent to the locking base 41 so as to be rotatable relative to the spool 2, a pawl 43 that restricts the rotation of the spool 2 when the locking gear 42 rotates relative to the spool 2, a vehicle sensor 44 that detects the acceleration or inclination of the vehicle body and restricts the rotation of the locking gear 42, a flywheel 45 that detects a sudden withdrawal of the webbing and rotates, a gear ring 46 that is arranged coaxially with the spool 2 and engages with the flywheel 45 when it is activated to restrict the rotation of the spool 2, and a retainer cover 47 that houses the components of the locking mechanism 4 (the locking gear 42, the gear ring 46, etc.). For ease of explanation, the vehicle sensor 44 is omitted in FIG. 1, and the retainer cover 47 is omitted in FIG. 2.

[0028] The locking base 41 includes a shaft portion 41a fixed to the torsion bar 51, and a flange portion 41b forming a portion that restricts the movement of the pawl 43. An insertion hole 41c for fixing the torsion bar 51 is formed in the center of the shaft portion 41a. The outer periphery of the shaft portion 41a is formed in a polygonal shape, and a paddle gear (not shown) of the pretensioner 3 is disposed in this portion.

[0029] A pawl 43 is disposed in the flange portion 41b so as to be able to protrude and retract radially outward. When the locking mechanism 4 is not activated, the pawl 43 is housed within the outer diameter of the flange portion 41b. When the locking mechanism 4 is activated, the pawl 43 protrudes radially outward beyond the outer diameter of the flange portion 41b and engages with internal teeth 11c formed in the first opening 11a of the base frame 11. By engaging the pawl 43 with the base frame 11 in this manner, it is possible to restrict rotation of the locking base 41 in the webbing-pulling out direction.

[0030] The lock gear 42 includes, for example, an outer peripheral wall 42a that forms a space for oscillatingly accommodating the flywheel 45, and external teeth 42b formed on the outer surface of the outer peripheral wall 42a. When the webbing is unwound at a speed faster than a normal speed, the flywheel 45 oscillates and engages with internal teeth 46a formed on the gear ring 46. When the vehicle sensor 44 is activated, the actuator 44b of the vehicle sensor 44 engages with the external teeth 42b of the lock gear 42.

[0031] 2, the vehicle sensor 44 includes a spherical mass body 44a, an actuator 44b that is swung by the movement of the mass body 44a, a casing 44c that supports the mass body 44a so that it can revolve and the actuator 44b so that it can swung, and a sensor cover (not shown) that houses these. When the vehicle sensor 44 experiences deceleration or tilt of a predetermined value or more in the vehicle body, the balance of the mass body 44a is lost and the actuator 44b is pushed upward, and the tip of the actuator 44b engages with the external teeth 42b of the lock gear 42, restricting the rotation of the lock gear 42.

[0032] The gear ring 46 is a component having internal teeth 46a with which the tip of the flywheel 45 engages when the flywheel 45 detects a sudden withdrawal of the webbing. The retainer cover 47 has a bearing portion 47a that supports the end of the locking base 41, and the gear ring 46 is rotatably disposed on the outer periphery of the bearing portion 47a via a spacer 46b. The gear ring 46 is normally restrained by the lock limiting mechanism 7 so as not to rotate (except when the lock limiting mechanism 7 is activated).

[0033] As described above, the rotation of the lock gear 42 is restricted by the operation of the flywheel 45 or the vehicle sensor 44. When the rotation of the lock gear 42 is restricted, relative rotation occurs between the locking base 41 and the lock gear 42, and this relative rotation causes the pawl 43 to protrude radially outward from the flange portion 41b of the locking base 41. The pawl 43 protruding radially outward engages with the internal teeth 11c formed in the first opening 11a of the base frame 11, and the rotation of the spool 2 is restricted.

[0034] The energy absorbing mechanism 5 is, for example, a torsion bar 51 disposed on the central axis of the spool 2, with a first end 51a side fixed to the locking mechanism 4 and a second end 51b side connected to the spool 2. The torsion bar 51 is, for example, a rod-shaped metal member, and is an energy absorbing member that is plastically deformed by being twisted due to the rotation difference between the first end 51a and the second end 51b, and absorbs kinetic energy.

[0035] A first end 51a of the torsion bar 51 is inserted into an insertion hole 41c of the locking base 41 and fixed so as to be synchronously rotatable with the locking base 41. A tip of a second end 51b of the torsion bar 51 is journalled on a spring core (not shown) of the spring unit 8 and is biased in the webbing winding direction by a spiral spring (not shown) built into the spring unit 8.

[0036] Moreover, a first connection portion 51c connected to the spool 2 and a second connection portion 51d connected to the torque transmission mechanism 6 are formed on the second end portion 51b side of the torsion bar 51. By connecting the first connection portion 51c to the spool 2, the second end portion 22 of the spool 2 and the second end portion 51b of the torsion bar 51 can be rotated in synchronization with each other. Furthermore, by connecting the second connection portion 51d to the torque transmission mechanism 6, the torque of the motor 61 can be transmitted to the torsion bar 51 to rotate the spool 2.

[0037] The torque transmission mechanism 6 includes, for example, a motor 61 that generates power to rotate the spool 2, a power transmission mechanism 62 that transmits the power of the motor 61 to the spool 2, and a gear retainer 63 and a gear case cover 64 that house the power transmission mechanism 62.

[0038] The power transmission mechanism 62 includes, for example, a motor gear 62a disposed on the output shaft of the motor 61, a shaft gear 62b connected to the spool 2 (the second connection portion 51d of the torsion bar 51), and a clutch 65 disposed between the motor gear 62a and the shaft gear 62b. The clutch 65 is a component that blocks the transmission of rotational force from the spool 2 to the motor 61 and transmits the rotational force from the motor 61 to the spool 2.

[0039] The clutch 65 includes, for example, a drive gear 65a that is rotatably supported on an axis (a boss 63a formed on the gear retainer 63) separate from the rotating shaft of the spool 2 and rotates in accordance with the rotation of the output shaft of the motor 61, a clutch gear 65b that is rotatably supported coaxially with the drive gear 65a and is connected to the rotating shaft of the spool 2 via a shaft gear 62b, a clutch pawl 65c provided on the drive gear 65a, and a clutch spring 65d that biases the clutch pawl 65c in a predetermined direction.

[0040] The clutch pawl 65c is configured to move and engage with the clutch gear 65b by centrifugal force generated by the rotation of the drive gear 65a, and not to engage with the clutch gear 65b when the rotation of the drive gear 65a is stopped.

[0041] The gear retainer 63 has an opening 63b at a portion where the rotating shaft of the spool 2 is inserted, a retainer bearing 63c is disposed in the opening 63b, and a shaft gear bearing 63d is disposed inside the retainer bearing 63c.

[0042] Although not shown, the torque transmission mechanism 6 may have a connector gear between the motor gear 62a and the drive gear, or may have an idle gear between the clutch gear and the shaft gear. The torque transmission mechanism 6 may have a known configuration, for example, as described in JP 2020-11647 A.

[0043] The torque transmission mechanism 6 has functions such as pre-winding the webbing based on a signal from a millimeter wave radar or the like that measures the distance between vehicles, assisting in winding the webbing when the tongue of the webbing is released from the buckle, and repeatedly pulling the webbing to give a warning based on a signal from a system that detects occupants falling asleep while driving, looking away from the vehicle, etc. In addition, the torque transmission mechanism 6 functions as a part of the energy absorption mechanism 5 when the lock limiting mechanism 7 is activated, as will be described later.

[0044] The lock limiting mechanism 7 is configured to release the operating state of the lock mechanism 4 by the torque transmission mechanism 6 after the lock mechanism 4 is activated to restrict the rotation of the spool 2, and then not activate the lock mechanism 4. The lock limiting mechanism 7 is configured to, for example, release the operating state of the lock mechanism 4 by the torque transmission mechanism 6 once after the lock mechanism 4 is activated, and then not allow the lock mechanism 4 to be activated again, thereby maintaining the released state of the rotation restriction state of the lock gear 42 based on the operation of the vehicle sensor 44, and maintaining the released state of the rotation restriction state of the spool 2 based on the operation of the flywheel 45.

[0045] The lock limiting mechanism 7 includes, for example, a lever 71 having a first restraining portion 71a that restrains the vehicle sensor 44 from engaging with the lock gear 42 when not in operation and a second restraining portion 71b that restrains the gear ring 46 from rotating, a drive device 72 that operates the lever 71, an initial spring 73 that urges the lever 71 to an initial position, and a cover 74 that houses these components. The lock limiting mechanism 7 is disposed, for example, on the outside of the retainer cover 47 of the locking mechanism 4.

[0046] 3(A) and 3(B), the lever 71 includes a first restraining portion 71a, a second restraining portion 71b, an insertion portion 71c rotatably arranged on a shaft portion formed on the outer surface of the retainer cover 47, and a connecting portion 71d connected to the drive device 72. The first restraining portion 71a and the second restraining portion 71b are arranged on the opposite side of the insertion portion 71c to the connecting portion 71d. Note that the configuration of the lever 71 is not limited to the configuration shown in the drawings.

[0047] The vehicle sensor 44 has an actuator 44b that can engage with the lock gear 42, and the first restraining portion 71a is configured to press down the actuator 44b of the vehicle sensor 44 and separate it from the lock gear 42 when activated. The first restraining portion 71a is, for example, a protrusion formed to extend substantially parallel to the insertion portion 71c. The first restraining portion 71a may be configured to restrain multiple points of the actuator 44b (for example, a protrusion that engages with the lock gear 42 and a head portion located at the top of the mass body 44a) when activated.

[0048] The gear ring 46 has a plurality of protrusions 46c formed on its outer circumferential surface, and the second restraining portion 71b is configured to engage with one of the protrusions 46c when not in operation and to move away from the protrusions 46c when in operation. The second restraining portion 71b is, for example, a protrusion formed to extend substantially parallel to the first restraining portion 71a. The retainer cover 47 is formed with an opening 47b for allowing the second restraining portion 71b to access the protrusions 46c of the gear ring 46.

[0049] The initial spring 73 is a component that biases the lever 71 in a direction that maintains a state in which the first restraining portion 71a is separated from the actuator 44b of the vehicle sensor 44 and the second restraining portion 71b is engaged with the projection 46c of the gear ring 46.

[0050] The driving device 72 is, for example, a solenoid that reciprocates an actuator based on an electric signal. If necessary, a joint 75 may be disposed between the actuator of the driving device 72 and the connecting portion 71d of the lever 71. Note that the solenoid is merely one example of the driving device 72, and the driving device 72 is not limited to this configuration.

[0051] The lock limiting mechanism 7 is configured to maintain a disengaged state between the vehicle sensor 44 and the lock gear 42 when activated. The lock limiting mechanism 7 is also configured to restrict the gear ring 46 from rotating when not activated, and to release the restricted state of the gear ring 46 when activated, allowing the gear ring 46 to rotate.

[0052] For example, when not in operation (normally), the lock limiting mechanism 7 keeps the solenoid actuator in a protruding state, separating the first restraining portion 71a of the lever 71 from the actuator 44b of the vehicle sensor 44, and engaging the second restraining portion 71b of the lever 71 with the protrusion 46c of the gear ring 46.

[0053] When activated (when the lock mechanism 4 is unlocked), the lock limiting mechanism 7 retracts the solenoid actuator, pressing the first restraining portion 71a of the lever 71 against the actuator 44b of the vehicle sensor 44 and disengaging the second restraining portion 71b of the lever 71 from the protrusion 46c of the gear ring 46.

[0054] The lock limiting mechanism 7 is a component that, by operating the torque transmission mechanism 6 after the locking mechanism 4 is operated, once releases the engagement between the pawl 43 and the base frame 11 (internal teeth 11C), and releases the locking mechanism 4 so that the pawl 43 does not open again, thereby enabling the spool 2 to rotate. As described above, the operation of the locking mechanism 4 is based on a case caused by the operation of the vehicle sensor 44 (when the acceleration or inclination of the vehicle body is detected) and a case caused by the operation of the flywheel 45 (when a sudden withdrawal of the webbing is detected). The lock limiting mechanism 7 can forcibly switch the vehicle sensor 44 to the OFF state and can forcibly switch the gear ring 46 to the rotatable state by operating the lever 71.

[0055] In a state in which the gear ring 46 is restrained by the lever 71, the gear ring 46 is in a state in which it does not rotate, and therefore when the flywheel 45 detects a sudden withdrawal of the webbing and engages with the internal teeth 46a of the gear ring 46, the rotation of the lock gear 42 is restricted and the lock gear 42 rotates relative to the spool 2. On the other hand, when the gear ring 46 transitions to a rotatable state, even when the flywheel 45 detects a sudden withdrawal of the webbing and engages with the internal teeth 46a of the gear ring 46, the gear ring 46 is rotatable, so the rotation of the lock gear 42 is not restricted and the lock gear 42 rotates in synchronization with the spool 2.

[0056] The lock limiting mechanism 7 described above is controlled by an on-board ECU (Electronic Control Unit) like other on-board electronic devices including the retractor 1. The lock limiting mechanism 7 and the torque transmission mechanism 6 release the lock of the spool 2 by the locking mechanism 4 and maintain that state, thereby allowing the motor 61 to control the rotation of the spool 2. Therefore, the spool 2 can be rotated at a set load lower than the set load (load that causes twisting) of the torsion bar 51, and an energy absorption load suitable for the collision speed, the physique and posture of the occupant, etc. can be reproduced, allowing the energy of the occupant to be flexibly absorbed.

[0057] Furthermore, when the lock limiting mechanism 7 is not activated, the locked state of the spool 2 is maintained by the locking mechanism 4, so that the torsion bar 51 can absorb energy in the same way as a normal retractor. Furthermore, since the present embodiment is provided with the motor 61, the motor load can be added to the set load of the torsion bar 51, and the set load can also be adjusted to be higher than the set load of the torsion bar 51.

[0058] Hereinafter, the control method of the retractor 1 will be described with reference to Fig. 4 to Fig. 8(B). Here, Fig. 4 is an operation flow diagram of the lock limiting mechanism. Fig. 5 is an explanatory diagram showing the relationship between the lock limiting mechanism and the vehicle sensor in a state before the lock mechanism and the lock limiting mechanism are operated, (A) being a front view and (B) being a rear view. Fig. 6 is an explanatory diagram showing the relationship between the lock limiting mechanism and the vehicle sensor in a state after the lock mechanism is operated (before the lock limiting mechanism is operated), (A) being a front view and (B) being a rear view. Fig. 7 is an explanatory diagram showing the relationship between the lock limiting mechanism and the vehicle sensor in a state after the lock limiting mechanism is operated, (A) being a front view and (B) being a rear view. Fig. 8 is an explanatory diagram showing the relationship between the lock limiting mechanism and the gearing, (A) showing the state before the lock limiting mechanism is operated and (B) showing the state after the lock limiting mechanism is operated. For ease of explanation, the drive device 72 of the lock limiting mechanism 7 is omitted in each of Figures 5(A) to 7(B). For ease of explanation, cross-sectional views of the gear ring 46 are shown in Figures 5(B), 6(B) and 7(B).

[0059] As shown in FIG. 4, the control method of the retractor 1 includes an information acquisition processing step Step 1 for acquiring information from various on-board sensors, a collision occurrence recognition step Step 2 for recognizing that the vehicle has collided based on the acquired information, a lock mechanism operation step Step 3 for operating the lock mechanism 4 when a collision occurs, a lock restriction mechanism operation determination step Step 4 for determining whether or not to operate the lock restriction mechanism 7, an unlocking step Step 5 for operating the lock restriction mechanism 7 to unlock the lock mechanism 4, and a motor operation determination step Step 6 for determining whether or not to operate the motor 61.

[0060] In the collision occurrence recognition step Step 2, if it is recognized that a vehicle collision has occurred (if Yes), the process proceeds to the next step of lock mechanism operation step Step 3, and if it is recognized that a vehicle collision has not occurred (if No), the information acquisition processing step Step 1 is repeated. The collision occurrence recognition step Step 2 is processed by, for example, a webbing sensor including a flywheel 45 and a vehicle sensor 44.

[0061] Up until the collision occurrence recognition step Step2, the lever 71 of the lock limit mechanism 7 is held in a state in which the first restraining portion 71a is separated from the actuator 44b of the vehicle sensor 44 as shown in Figures 5(A) and 5(B), and the second restraining portion 71b is engaged with the protrusion 46c of the gear ring 46 as shown in Figure 8(A). Also, as shown in Figures 5(A) and 5(B), during normal driving, the actuator 44b of the vehicle sensor 44 is held in a state separated from the external teeth 42b of the lock gear 42, and the flywheel 45 is held in a state separated from the internal teeth 46a of the gear ring 46.

[0062] The lock mechanism operation step Step 3 is a step of restricting the rotation of the spool 2 by, for example, the operation of the vehicle sensor 44 or the operation of the flywheel 45. Specifically, this is a step of engaging the pawl 43 of the lock mechanism 4 with the internal teeth 11c of the base frame 11.

[0063] 6(A) and 6(B), when the vehicle sensor 44 detects the acceleration or inclination of the vehicle body and the mass body 44a moves forward, the actuator 44b is pushed up and the tip of the actuator 44b engages with the external teeth 42b of the lock gear 42. The engagement between the actuator 44b and the lock gear 42 restricts the rotation of the lock gear 42, and the pawl 43 is activated to restrict the rotation of the spool 2.

[0064] The lock restriction mechanism operation determination step Step 4 is a step for determining whether or not to release the lock of the lock mechanism 4 based on the information acquired in the information acquisition processing step Step 1. For example, if the load to be absorbed is smaller than the set load of the torsion bar 51 (if Yes) based on the relationship between the information on the occupant's physique and posture and the collision speed of the vehicle, the process proceeds to the next step of the lock release step Step 5.

[0065] In addition, in the lock limiting mechanism operation determination step Step 4, if the load to be absorbed as energy is greater than the set load of the torsion bar 51 (if No), the lock limiting mechanism 7 is not activated and the lock mechanism 4 is kept activated, and the process proceeds to the next step, the motor operation determination step Step 6.

[0066] As described above, the retractor 1 of this embodiment includes the motor 61 (torque transmission mechanism 6) that rotates the spool 2, and therefore the motor load can be added when the energy absorption mechanism 5 is activated. Therefore, the control method for the retractor 1 may include a motor operation determination step Step 6 for determining whether or not to operate the motor 61 to increase the set load of the energy absorption.

[0067] In the motor operation determination step Step 6, it is determined based on the information acquired in the information acquisition processing step Step 1 whether the set load for absorbing energy during a vehicle collision should be set to the set load (medium load) of the torsion bar 51 or to a set load (high load) higher than the set load of the torsion bar 51. If the load is medium (No), the process proceeds to a medium load mode step Step 7 in which only the torsion bar 51 is operated without operating the motor 61.

[0068] Moreover, in the case of a high load (in the case of Yes), the process proceeds to a high load mode step Step 8 in which the motor 61 is operated to add the operating load of the motor 61 to the set load of the torsion bar 51. At this time, it is possible to determine how much the motor load should be added based on the collision speed, the physique information of the occupant, and the like, and to rotate the motor 61 to suppress the withdrawal of the webbing so that the motor load to be added can be applied to the spool 2.

[0069] The unlocking step Step 5 is a process of releasing the state (locked state) in which the rotation of the spool 2 is restricted by the locking mechanism 4. Specifically, the torque transmission mechanism 6 is operated to rotate the spool 2 in the webbing winding direction, and the engagement between the pawl 43 and the base frame 11 (internal teeth 11C) is once released, and then the lock limiting mechanism 7 is operated to prevent the locking mechanism 4 from being operated again. By this operation, the lock limiting mechanism 7 and the torque transmission mechanism 6 are operated to release the locked state of the spool 2, and the state in which the rotation of the spool 2 can be controlled by the torque transmission mechanism 6 is created. In this way, by releasing the locking mechanism 4 at the time of a vehicle collision and controlling the rotation of the spool 2 by the torque transmission mechanism 6, the energy absorption load can be set arbitrarily by the motor load, and even a set load lower than the set load of the torsion bar 51 can be freely set.

[0070] When the lock limiting mechanism 7 is activated, the first restraining portion 71a of the lever 71 of the lock limiting mechanism 7 pushes down the actuator 44b of the vehicle sensor 44 and separates it from the lock gear 42 as shown in Figures 7(A) and 7(B), and the second restraining portion 71b separates it from the protrusion 46c of the gear ring 46 as shown in Figure 8(B). This operation releases the spool 2 from the locked state by the vehicle sensor 44 and the flywheel 45.

[0071] Furthermore, the lock limiting mechanism 7 may be configured to rotate the lever 71 to return the lock limiting mechanism 7 to a non-operating state when an abnormality is detected. For example, the method of controlling the retractor 1 may include, after the lock releasing step Step 5, an abnormality detecting step Step 51 for detecting an abnormality in the retractor 1, and a lock limiting mechanism releasing step Step 52 for releasing the operation of the lock limiting mechanism 7. If no abnormality is detected in the abnormality detecting step Step 51 (No), the process proceeds to a low load mode step Step 9 in which the rotation of the spool 2 can be controlled by the torque transmission mechanism 6.

[0072] On the other hand, if an abnormality is detected in the abnormality detection step 51, such as an abnormality in which the motor 61 cannot be operated (Yes), the operation of the lock limit mechanism 7 is released in the lock limit mechanism release step 52. This operation allows the spool 2 to be returned to a lockable state by the lock limit mechanism 7, and the process transitions to the medium load mode step 7, where the torsion bar 51 can absorb energy.

[0073] As shown in Fig. 4, the retractor 1 according to this embodiment is configured to be able to switch between a medium load mode in which only the torsion bar 51 is used, a high load mode in which both the torsion bar 51 and the motor 61 are used, and a low load mode in which only the motor 61 is used when absorbing energy after a vehicle collision. Fig. 9 is an explanatory diagram showing an example of a method for controlling the energy absorption load, where (A) shows an example of single load setting, and (B) shows an example of multiple load setting. In Fig. 9(A) and Fig. 9(B), the horizontal axis shows the stroke S (mm) and the vertical axis shows the energy absorption load F (kN).

[0074] 9(A), the load fluctuation FM in the medium load mode is indicated by a dotted line, the load fluctuation FH in the high load mode is indicated by a dashed line, and the load fluctuations FL1 to FL3 in the low load mode are indicated by solid lines. As shown in the figure, in the high load mode, the set load of energy absorption is set to F1, and in the medium load mode, the set load of energy absorption is set to F2, with a relationship of F1>F2.

[0075] When the lock limiting mechanism 7 is operated to release the lock mechanism 4, the energy absorption load can be freely controlled only by operating the motor 61 without relying on the torsion bar 51. For example, as shown in the figure, the load can be freely set to F3 to F5, which are values ​​lower than F2. Here, the load variation FL1 (load setting F3) shows a case where the collision speed is medium, the load variation FL2 (load setting F4) shows a case where the collision speed is medium to low, and the load variation FL3 (load setting F5) shows a case where the collision speed is low, with the relationship being F3>F4>F5.

[0076] If the collision speed in the medium load mode is 50km / h, for example, the medium speed is set within a range of 30 to 50km / h, the medium-low speed within a range of 10 to 30km / h, and the low speed within a range of 0 to 10km / h. Note that, although the case where the load setting in the low load mode is set to three stages (low speed, medium-low speed, medium speed) has been described here, the load setting in the low load mode may be set to fewer than three stages or more than three stages.

[0077] 9(B), since the energy absorption load can be controlled only by the motor load when absorbing energy after a vehicle collision, multiple energy absorption loads can be set for one collision event by changing the rotation speed of the motor 61. For example, the trajectory of the load change can be controlled to suit conditions such as when multiple collisions occur, when the collision speed signal changes, when working in conjunction with an airbag device, when the stroke amount of the occupant increases, etc.

[0078] For example, the illustrated load change FA shows a case where the initial load setting is set to F3 (medium speed), and the latter load setting is set to F4 (medium-low speed). The illustrated load change FB shows a case where the initial load setting is set to F4 (medium-low speed), and the latter load setting is set to F5 (low speed). The illustrated load change FC shows a case where the initial load setting is set to F5 (low speed), and the latter load setting is set to F3 (medium speed).

[0079] The load variation FA is set, for example, when the first collision is a medium-speed collision and the second collision is a low-medium-speed collision, when the amount of energy of the occupant is reduced during a medium-speed collision and it is desired to reduce the energy absorption load, etc. The case where the amount of energy of the occupant is reduced corresponds to the case where the airbag device cooperates with the vehicle and the change in the amount of stroke of the occupant is reduced, etc.

[0080] The load variation FB is set, for example, when the first collision is a low-to-medium speed collision and the second collision is a low-to-medium speed collision, or when the amount of energy absorbed by the occupant is small during a low-to-medium speed collision and it is desired to lower the energy absorption load.

[0081] The load variation FC is set, for example, when the first collision is a low-speed collision and the second collision is a medium-speed collision, when the amount of energy of the occupant increases in a low-speed collision and it is desired to increase the energy absorption load, etc. The case where the amount of energy of the occupant increases corresponds to the case where the change in the stroke amount of the occupant increases, etc.

[0082] In the load variations FA to FC, the set load is shown to be changed in the initial and later stages, but this is merely an example of the load variation and is not limited to the settings shown in the figures. For example, the set load may be changed in three stages, the initial stage, the middle stage, and the later stage, or the set load may be gradually changed from the initial set load over the entire stroke S.

[0083] According to the retractor 1 of this embodiment described above, by disposing the lock limiting mechanism 7 that holds the restriction on rotation of the spool 2 released by preventing the locking mechanism 4 from operating, after the locking mechanism 4 is operated to restrict the rotation of the spool 2, the locking mechanism 4 is released from its operating state by the torque transmission mechanism 6, and then the locking mechanism 4 is prevented from operating by the lock limiting mechanism 7. Therefore, according to the retractor 1 of this embodiment, the energy absorption load can be freely controlled without being influenced by the set load of the torsion bar 51.

[0084] Next, a seatbelt device according to one embodiment of the present invention will be described with reference to Fig. 10. Here, Fig. 10 is an overall configuration diagram showing a seatbelt device according to one embodiment of the present invention.

[0085] The seat belt device 100 according to this embodiment shown in FIG. 10 includes a webbing W for restraining an occupant, a retractor 1 for winding up the webbing W, a guide anchor 101 provided on the vehicle body side for guiding the webbing W, a belt anchor 102 for fixing the webbing W to the vehicle body side, a buckle 103 arranged on the side of the seat Se, and a tongue 104 arranged on the webbing W, and the retractor 1 has, for example, the configuration shown in FIG. 1.

[0086] The components other than the retractor 1 will be briefly described below. The seat Se includes, for example, a seating portion Se1 on which an occupant sits, a backrest portion Se2 located behind the occupant, and a headrest portion Se3 that supports the occupant's head. The retractor 1 is often built into, for example, a B-pillar of a vehicle body. In addition, the buckle 103 is generally often disposed on the side of the seating portion Se1, and the belt anchor 102 is generally disposed on the lower surface of the seating portion Se1. In addition, the guide anchor 101 is generally disposed on the B-pillar. One end of the webbing W is connected to the belt anchor 102, and the other end is connected to the retractor 1 via the guide anchor 101.

[0087] Therefore, when the tongue 104 is fitted into the buckle 103, the webbing W is pulled out from the retractor 1 while sliding through the insertion hole of the guide anchor 101. When an occupant fastens the seat belt or releases the seat belt when getting off the vehicle, the spring unit 8 of the retractor 1 acts to retract the webbing W until a certain load is applied.

[0088] The above-described seat belt device 100 is a normal seat belt device for the front seat to which the retractor 1 according to the above-described embodiment is applied. Therefore, according to the seat belt device 100 according to this embodiment, by disposing the lock limiting mechanism 7 that releases the restriction on the rotation of the spool 2 by the locking mechanism 4 after the locking mechanism 4 is actuated, the energy absorption load can be freely controlled without being influenced by the set load of the torsion bar 51.

[0089] The seat belt device 100 according to the present embodiment is not limited to application to a front seat, and can be easily applied to a rear seat, for example, by omitting the guide anchor 101. The seat belt device 100 according to the present embodiment can also be used in vehicles other than automobiles.

[0090] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0091] 1 Retractor 2 Spools 3 Pretensioner 4 Locking mechanism 5 Energy absorption mechanism 6 Torque transmission mechanism 7 Lock Restriction Mechanism 8 Spring unit 11 Base frame 11a First opening 11b Second opening 11c internal teeth 11d Thai Plate 21 First end 22 Second end 31 Power transmission device 32 Guide member 33 Gas Generator 34 Cover member 41 Rocking Base 41a Shaft 41b Flange part 41c Insertion hole 42 Lock Gear 42a Outer wall 42b External teeth 43 Paul 44 Vehicle Sensors 44a mass body 44b Actuator 44c casing 45 Flywheel 46 Gearing 46a Internal teeth 46b Spacer 46c protrusion 47 Retainer cover 47a Bearing section 47b Opening 51 Torsion bar 51a First end 51b Second end 51c First connection part 51d Second connection part 61 Motor 62 Power transmission mechanism 62a Motor gear 62b Shaft gear 63 Gear retainer 63a Boss 63b opening 63c retainer bearing 63d Shaft Gear Bearing 64 Gear case cover 65 Clutch 65a drive gear 65b clutch gear 65c clutch pawl 65d clutch spring 71 Lever 71a First restraint part 71b Second restraint part 71c Insertion part 71d Connecting part 72 Drive unit 73 Initial Spring 74 Cover 75 Joints 100 Seat belt device 101 Guide Anchor 102 Belt anchor 103 Buckle 104 Tongue Step 1: Information acquisition process Step 2: Collision occurrence recognition step Step 3: Lock mechanism activation step Step 4: Lock restriction mechanism operation determination step Step 5: Unlocking step Step 51 Anomaly detection step Step 52 Lock restriction mechanism release step Step 6 Motor operation judgment step Step 7 Medium load mode step Step 8 High Load Mode Step Step 9: Low load mode step

Claims

1. A retractor including: a spool that winds up a webbing for restraining an occupant; a locking mechanism that restricts rotation of the spool in a webbing-retracting direction in an emergency; an energy absorbing mechanism that absorbs kinetic energy of the occupant by limiting a load applied to the webbing when the locking mechanism is activated; and a torque transmission mechanism that transmits torque of a motor to the spool to rotate it, a lock limiting mechanism that prevents the locking mechanism from operating to maintain a state in which the restriction on rotation of the spool is released; The lock limiting mechanism is configured such that, after the locking mechanism is activated to restrict rotation of the spool, the torque transmission mechanism releases the activated state of the locking mechanism, and then the locking mechanism is prevented from being activated. A retractor characterized by:

2. 2. The retractor according to claim 1, wherein the lock mechanism includes a lock gear arranged coaxially with the spool so as to be rotatable relative to the spool, a pawl that restricts rotation of the spool when the lock gear rotates relative to the spool, a vehicle sensor that detects acceleration or inclination of a vehicle body and restricts rotation of the lock gear, a flywheel that detects a sudden pull-out of the webbing and rotates, and a gear ring arranged coaxially with the spool and capable of engaging with the flywheel when the flywheel is activated to restrict rotation of the spool, and the lock limit mechanism is configured to maintain a released state of the rotation restriction state of the spool based on the operation of the vehicle sensor, and to maintain a released state of the rotation restriction state of the spool based on the operation of the flywheel.

3. 3. The retractor according to claim 2, wherein the lock limiting mechanism is configured to restrict rotation of the gear ring when not actuated, and to release the restricted state of the gear ring to allow rotation of the gear ring when actuated.

4. The retractor according to claim 2 , wherein the lock limiting mechanism is configured to maintain a disengaged state between the vehicle sensor and the lock gear when activated.

5. 3. The retractor according to claim 2, wherein the lock limiting mechanism includes a lever having a first restraining portion that restrains the vehicle sensor from engaging with the lock gear when the lock limiting mechanism is not activated and a second restraining portion that restrains the gear ring from rotating, and a drive device that operates the lever, and is configured to operate the lever when the lock limiting mechanism is activated to release the restraint of the gear ring by the first restraining portion and to restrain the vehicle sensor.

6. The retractor according to claim 5 , wherein the vehicle sensor includes an actuator engageable with the lock gear, and the first restraint portion is configured to press the actuator downward and away from the lock gear when activated.

7. 6. The retractor according to claim 5, wherein the gear ring has a plurality of protrusions formed on an outer peripheral surface thereof, and the second restraint portion is configured to engage with one of the protrusions when inactive and to move away from the protrusion when active.

8. The retractor according to claim 5, wherein the lock limiting mechanism is configured to operate the lever to return the lock limiting mechanism to a non-operated state when an abnormality is detected.

9. 2. The retractor of claim 1, wherein the energy absorbing mechanism is a torsion bar disposed on a central axis of the spool, the first end of the torsion bar being fixed to the locking mechanism and the second end of the torsion bar being connected to the spool.

10. A seat belt device comprising the retractor according to any one of claims 1 to 9.

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