Webbing winding device

Abstract

In this webbing winding device, a load applied to a spool for allowing rotation of the spool in the pull-out direction due to bending deformation of a wire is made higher than a load applied to the spool for allowing rotation of the spool in the pull-out direction due to torsional deformation of a torsion shaft. Therefore, when a rotational force in a winding direction is transmitted to a pinion, relative rotation of the pinion with respect to the spool in the winding direction can be effectively restricted by the wire, and torsional deformation of the torsion shaft can be effectively suppressed.

Description

Webbing retractor

[0001] The present invention relates to a webbing take-up device in which rotation of a spool in the unwinding direction is permitted when rotation of a restricting body in the unwinding direction is restricted.

[0002] In the seat belt retractor described in JP 2014-201122 A, when rotation of the ratchet gear in the unwinding direction is restricted, the wire is bent and the torsion bar is twisted, allowing rotation of the winding drum in the unwinding direction. In addition, the pretensioner mechanism transmits rotational force in the winding direction to the winding drum.

[0003] In this seatbelt retractor, if the pretensioner mechanism transmits a rotational force in the retraction direction to the ratchet gear, it is preferable that the torsional deformation of the torsion bar due to the rotational force can be effectively suppressed, and it is also preferable that fluctuations in the force limiter load (the load required to allow rotation of the retraction drum in the unwinding direction) can be suppressed.

[0004] In consideration of the above, an object of the present invention is to provide a webbing retractor that can effectively suppress torsional deformation of a deformable member due to a rotational force in the retraction direction that is transmitted to a regulating body, and a webbing retractor that can suppress fluctuations in force limiter load.

[0005] A webbing take-up device of a first aspect of the present invention includes a spool around which a webbing worn by an occupant is rotated in a take-up direction to be taken up, and around which the webbing is unwound and rotated in the unwinding direction; a restricting body that is capable of transmitting a rotational force in the take-up direction and restricting rotation in the unwinding direction; a long material that, when the rotational force in the take-up direction is transmitted to the restricting body, restricts the relative rotation of the restricting body with respect to the spool in the take-up direction, thereby transmitting the rotational force in the take-up direction to the spool, and that, when the rotation of the restricting body in the unwinding direction is restricted, is moved in the longitudinal direction and bent and deformed, thereby allowing rotation of the spool in the unwinding direction; and a deformable member that, when the rotation of the restricting body in the unwinding direction is restricted, is torsionally deformed, allowing rotation of the spool in the unwinding direction, and the load on the spool that is caused by the long material being bent and deformed to allow rotation of the spool in the unwinding direction is made equal to or higher than the load on the spool that is caused by the torsionally deformed long material, allowing rotation of the spool in the unwinding direction.

[0006] A webbing take-up device of a second aspect of the present invention includes a spool around which the webbing worn by an occupant is rotated in the take-up direction to be taken up, and around which the webbing is unwound and rotated in the unwound direction; a regulating body that is capable of transmitting a rotational force in the take-up direction and restricting rotation in the unwound direction; a long material that, when the rotational force in the take-up direction is transmitted to the regulating body, restricts the relative rotation of the regulating body with respect to the spool in the take-up direction, thereby transmitting the rotational force in the take-up direction to the spool, and that, when the rotation of the regulating body in the unwound direction is restricted, is moved in the longitudinal direction and bent and deformed, thereby allowing rotation of the spool in the unwound direction; and a deformation member that, when the rotation of the regulating body in the unwound direction is restricted, is torsionally deformed, allowing rotation of the spool in the unwound direction, and that begins to torsionally deform when the load for bending and deforming the long material is reduced when rotation of the spool in the unwound direction is allowed.

[0007] A webbing take-up device of a third aspect of the present invention is the webbing take-up device of the first or second aspect of the present invention, wherein the long material is engaged with the regulating body and is arranged on the spool in a state where it is deformed by the spool.

[0008] A webbing take-up device of a fourth aspect of the present invention is a webbing take-up device of any one of the first to third aspects of the present invention, wherein the bending load resistance of the long material against a rotational force in the winding direction transmitted to the regulating body is made equal to or higher than the torsional load resistance of the deformable member against a rotational force in the winding direction transmitted to the regulating body.

[0009] A webbing take-up device of a fifth aspect of the present invention is a webbing take-up device of any one of the first to fourth aspects of the present invention, which is provided with a locking portion and is assembled to the deformable member to restrict movement of the locking portion toward the deformable member, thereby disposing the regulating body between the locking portion and the spool and allowing the regulating body to be separated from the locking portion.

[0010] In the webbing take-up device of the first aspect of the present invention, the spool is rotated in the take-up direction, and the webbing to be worn by an occupant is taken up onto the spool, and the webbing is unwound from the spool, causing the spool to rotate in the unwound direction. Furthermore, when rotation of the restrictor body in the unwound direction is restricted, the long material is moved in the longitudinal direction and bent and deformed, and the deformation member is twisted and deformed, allowing rotation of the spool in the unwound direction. Furthermore, when a rotational force in the take-up direction is transmitted to the restrictor body, the long material restricts relative rotation of the restrictor body with respect to the spool in the take-up direction, and the rotational force in the take-up direction is transmitted to the spool.

[0011] Here, the load on the spool that causes bending deformation of the long material to allow rotation of the spool in the withdrawal direction is set to be the same as or higher than the load on the spool that causes torsional deformation of the deformable member to allow rotation of the spool in the withdrawal direction. Therefore, when a rotational force in the winding direction is transmitted to the regulating body, the long material can effectively limit the relative rotation of the regulating body with respect to the spool in the winding direction, and torsional deformation of the deformable member can be effectively suppressed.

[0012] In the webbing take-up device of the second aspect of the present invention, the spool is rotated in the take-up direction, and the webbing to be worn by an occupant is taken up onto the spool, and the webbing is unwound from the spool, causing the spool to rotate in the unwound direction. Furthermore, when rotation of the restrictor body in the unwound direction is restricted, the long material is moved in the longitudinal direction and bent and deformed, and the deformation member is twisted and deformed, allowing rotation of the spool in the unwound direction. Furthermore, when a rotational force in the take-up direction is transmitted to the restrictor body, the long material restricts relative rotation of the restrictor body with respect to the spool in the take-up direction, and the rotational force in the take-up direction is transmitted to the spool.

[0013] When the spool is allowed to rotate in the pull-out direction, the deformation member begins to twist when the load required to bend the elongated material is reduced, thereby suppressing fluctuations in the force limiter load (the load required to allow the spool to rotate in the pull-out direction).

[0014] In the webbing take-up device of the third aspect of the present invention, the long material is engaged with the restrictor, and the long material is disposed on the spool in a state in which it is deformed by the spool, thereby suppressing rattle of the long material relative to the spool and suppressing rattle between the restrictor and the spool.

[0015] In the webbing take-up device of the fourth aspect of the present invention, the bending load resistance of the elongated material against the rotational force in the take-up direction transmitted to the restrictor is set to be equal to or higher than the torsional load resistance of the deformable member against the rotational force in the take-up direction transmitted to the restrictor, so that when the rotational force in the take-up direction is transmitted to the restrictor, the elongated material can effectively limit the rotation of the restrictor in the take-up direction relative to the spool.

[0016] In the webbing take-up device of the fifth aspect of the present invention, the locking member is assembled to the deformable member, and movement of the locking portion of the locking member toward the deformable member is restricted, so that the restricting body is disposed between the locking portion and the spool and is capable of being separated from the locking portion. Therefore, when the locking portion rotates relative to the restricting body, friction between the locking portion and the restricting body can be suppressed.

[0017] It is a rear view seen from behind showing a webbing winding device according to the first embodiment of the present invention. It is a front view seen from the left showing a lock base etc. of the webbing winding device according to the first embodiment of the present invention. It is an exploded perspective view seen from the left showing the main part of the webbing winding device according to the first embodiment of the present invention. It is a cross-sectional view (cross-sectional view taken along line 3A-3A of FIG. 1A) showing the main part of the webbing winding device according to the first embodiment of the present invention. It is an enlarged view of region 3B of FIG. 3A. It is a cross-sectional view taken along line 4A-4A of FIG. 1A showing the main part of the webbing winding device according to the first embodiment of the present invention. It is a cross-sectional view taken along line 4B-4B of FIG. 1A showing the main part of the webbing winding device according to the first embodiment of the present invention. It is a cross-sectional view taken along line 4C-4C of FIG. 1A showing the main part of the webbing winding device according to the first embodiment of the present invention. It is a cross-sectional view taken along line 4D-4D of FIG. 1A showing the main part of the webbing winding device according to the first embodiment of the present invention. It is a cross-sectional view (cross-sectional view taken along line 5A-5A of FIG. 1A) showing the main part of the webbing winding device according to the first embodiment of the present invention. It is a cross-sectional view taken along line 5B-5B of FIG. 5A. It is a cross-sectional view taken at the position of line 5A-5A of FIG. 1A showing the first deformation stage of the wire in the webbing winding device according to the first embodiment of the present invention. It is a cross-sectional view along the wire showing the first deformation stage of the wire in the webbing winding device according to the first embodiment of the present invention. It is a cross-sectional view taken at the position of line 5A-5A of FIG. 1A showing the second deformation stage of the wire in the webbing winding device according to the first embodiment of the present invention. It is a cross-sectional view along the wire showing the second deformation stage of the wire in the webbing winding device according to the first embodiment of the present invention. It is a cross-sectional view taken at the position of line 5A-5A of FIG. 1A showing the third deformation stage of the wire in the webbing winding device according to the first embodiment of the present invention. It is a cross-sectional view along the wire showing the third deformation stage of the wire in the webbing winding device according to the first embodiment of the present invention. It is a cross-sectional view taken at the position of line 5A-5A of FIG. 1A showing the fourth deformation stage of the wire in the webbing winding device according to the first embodiment of the present invention. It is a cross-sectional view along the wire showing the fourth deformation stage of the wire in the webbing winding device according to the first embodiment of the present invention. It is a cross-sectional view taken at the position of line 5A-5A of FIG. 1A showing the fifth deformation stage of the wire in the webbing winding device according to the first embodiment of the present invention.12A ; FIG. 12B ; FIG. 12C is a cross-sectional view along the wire showing a fifth deformation stage of the wire in the webbing take-up device according to the first embodiment of the present invention; FIG. 12D is a graph showing the relationship between the allowable rotation stroke (horizontal axis) in the spool unwinding direction and the allowable rotation load (vertical axis) in the spool unwinding direction in the webbing take-up device according to the first embodiment of the present invention; FIG. 12E is a cross-sectional view (cross-sectional view taken along line 12A-12A in FIG. 12B ) showing a main portion of a webbing take-up device according to a second embodiment of the present invention; FIG. 12F is a front view, seen from the left, showing a lock base and the like of a webbing take-up device according to the second embodiment of the present invention; FIG. 12G is an exploded perspective view, seen from the right, showing a main portion of a webbing take-up device according to the second embodiment of the present invention; FIG. 12H is a cross-sectional view taken along line 14A-14A in FIG. 12A showing a main portion of a webbing take-up device according to the second embodiment of the present invention;

[0018] 1A shows a cross-sectional view of a webbing take-up device 10 according to a first embodiment of the present invention as seen from the rear. In the drawing, the right side of the webbing take-up device 10 is indicated by an arrow RH, and the upper side of the webbing take-up device 10 is indicated by an arrow UP.

[0019] The webbing take-up device 10 according to this embodiment is installed in a vehicle, and the front, right and upper sides of the webbing take-up device 10 are oriented, for example, outward in the vehicle width direction, rearward and upward of the vehicle, respectively.

[0020] 1A, the webbing retractor 10 is provided with a frame 12 having a U-shaped cross section as a support body, and the frame 12 is provided with a rear back plate (not shown), a left leg plate 12A, and a right leg plate 12B. The frame 12 is fixed to the vehicle body at the back plate, thereby installing the webbing retractor 10 on the vehicle.

[0021] A box-shaped cover plate 14 serving as a restricting member is fixed to the left side of the frame 12 (leg plate 12A), and the interior of the cover plate 14 is open to the right and closed from the right side by the leg plate 12A. A ratchet hole 14A is formed through the left wall of the cover plate 14, and ratchet teeth 14B serving as a restricting portion are formed around the entire periphery of the ratchet hole 14A.

[0022] A substantially cylindrical spool 16 (see FIGS. 2 and 3A) is rotatably supported between the leg plates 12A and 12B of the frame 12, with the left and right ends of the spool 16 penetrating the leg plates 12A and 12B, respectively. A guide groove 18 (see FIGS. 5A and 5B) that is annular in front view is coaxially formed on the left surface of the spool 16. The guide groove 18 is open to the left and has a substantially rectangular cross section. An insertion hole 20 is formed in the peripheral wall of the spool 16. The insertion hole 20 extends in the axial direction (left-right direction) of the spool 16 and communicates with the guide groove 18. The corner of the peripheral surface of the insertion hole 20 between the bottom surface (right surface) of the guide groove 18 and the bottom surface of the guide groove 18 on the winding direction side is a deformed surface 20A. The deformed surface 20A is curved convexly toward the winding direction as it extends leftward. A predetermined number (six in this embodiment) of trapezoidal columnar first recesses 16A (see Figures 4C and 4D) are formed on the peripheral surface of the right end of the spool 16, and the predetermined number of first recesses 16A extend in the axial direction of the spool 16 and are arranged at intervals around the circumferential direction of the spool 16.

[0023] A long strip-shaped webbing 22 is wound around the spool 16 from the base end in the longitudinal direction, and when the spool 16 is rotated in a winding direction (the direction of arrow A in Figure 2, etc.), the webbing 22 is wound around the spool 16, and when the webbing 22 is pulled out from the spool 16, the spool 16 is rotated in a pulling-out direction (the direction of arrow B in Figure 2, etc.). When the webbing 22 is pulled out from the spool 16, the webbing 22 is worn by an occupant seated in a vehicle seat.

[0024] A metal, substantially cylindrical torsion shaft 24 (see FIGS. 2 and 3A) serving as a first energy absorbing member (deformable member) is coaxially arranged within the spool 16 .

[0025] A predetermined number (six in this embodiment) of trapezoidal columnar first protrusions 24A (see FIG. 4C ) are integrally formed on the circumferential surface of the right end of the torsion shaft 24. The predetermined number of first protrusions 24A extend in the axial direction of the torsion shaft 24 and are spaced apart circumferentially of the torsion shaft 24. The first protrusions 24A are fitted into first recesses 16A of the spool 16, thereby connecting the right end of the torsion shaft 24 to be rotatable therewith, and causing the torsion shaft 24 to rotate integrally with the spool 16. The left portion of a substantially cylindrical connecting shaft 26 (see FIGS. 2 and 3A ) is coaxially inserted and threadedly engaged with the right end of the torsion shaft 24, and an axial (left-right) middle portion of the connecting shaft 26 is engaged with the spool 16 from the right side, restricting leftward movement of the torsion shaft 24.

[0026] A specific number (three in this embodiment) of trapezoidal columnar second protrusions 24B (see FIGS. 4A, 4B, and 4D) are integrally provided on the circumferential surface of the left end of the torsion shaft 24, and a specific number of first protrusions 24A extend in the axial direction of the torsion shaft 24 and are arranged at intervals in the circumferential direction of the torsion shaft 24. A substantially cylindrical screw hole 24C (see FIGS. 3A and 3B) is formed coaxially at the left end of the torsion shaft 24, and the screw hole 24C is open to the left and has a bottom surface (right surface) that is a concave surface with a conical side surface.

[0027] A biasing mechanism 28 is provided on the right side of the frame 12 (leg plate 12B), and a power spring (not shown) serving as a biasing member is provided within the biasing mechanism 28. The power spring is connected to the right end of the spool 16 via the right portion of the connecting shaft 26 and the right end of the torsion shaft 24, and the power spring biases the spool 16 in the winding direction.

[0028] A generally annular pinion 30 (see FIGS. 2 and 3A) serving as a connecting member constituting a restricting body is coaxially disposed on the left side of the spool 16. A specific number (three in this embodiment) of curved rectangular column-shaped second recesses 30A (see FIG. 4A) are formed on the circumferential surface of the pinion 30. The specific number of second recesses 30A extend in the axial direction of the pinion 30 and are spaced apart circumferentially around the pinion 30. The left end of the torsion shaft 24 is coaxially inserted into the pinion 30, and the second protrusion 24B of the torsion shaft 24 is inserted into the second recess 30A. The dimension of the second recess 30A in the circumferential direction of the pinion 30 is larger than the dimension of the second protrusion 24B in the circumferential direction of the torsion shaft 24, and the second protrusion 24B abuts against the end face of the second recess 30A in the winding direction. Therefore, the torsion shaft 24 and the spool 16 are rotatable by a predetermined amount in the pull-out direction relative to the pinion 30, but are unable to rotate in the winding direction relative to the pinion 30. A plurality of pinion teeth 30B are formed on the outer periphery of the left portion of the pinion 30, and the plurality of pinion teeth 30B are arranged at equal intervals around the circumferential direction of the pinion 30.

[0029] A generally annular plate-shaped lock base 32 (see FIGS. 1B, 2, and 3A) serving as a regulated member constituting a regulating body is coaxially provided on the left side of the pinion 30, and the lock base 32 is connected to the pinion 30 so as to be rotatable integrally with it. A plurality of pinion teeth 32A are formed on the outer periphery of the right part of the lock base 32, and the plurality of pinion teeth 32A are arranged at equal intervals in the circumferential direction of the lock base 32. The left part of the lock base 32 is coaxially inserted into the ratchet hole 14A of the cover plate 14, and a lock plate 32B serving as a regulated part is rotatably supported on the left part of the lock base 32.

[0030] A substantially cylindrical screw shaft 34 (see FIGS. 1B, 2, 3A, and 3B) serving as a locking member is coaxially fitted into the pinion 30 and the lock base 32, and the right end of the screw shaft 34 is threadedly engaged with the circumferential surface of the threaded hole 24C of the torsion shaft 24. An enlarged diameter portion 34A serving as a locking portion is formed coaxially in the middle of the axial direction (left-right direction) of the screw shaft 34, and the enlarged diameter portion 34A is disposed on the left side of the lock base 32 so as to be able to lock the movement of the lock base 32 to the left. The enlarged diameter portion 34A is slightly spaced from the lock base 32, forming a gap between it and the lock base 32. When the torsion shaft 24 rotates in the pull-out direction relative to the pinion 30 and the lock base 32, the frictional force between the enlarged diameter portion 34A and the lock base 32 prevents the enlarged diameter portion 34A from rotating in the winding direction relative to the torsion shaft 24. This prevents an increase in the amount of threading of the right end of the screw shaft 34 onto the circumferential surface of the screw hole 24C, thereby preventing an increase in the frictional force between the pinion 30 and the spool 16.

[0031] The right end face of the screw shaft 34 is in line contact with the bottom surface of the screw hole 24C, so that even when the enlarged diameter portion 34A is separated from the lock base 32, the relative rotation of the screw shaft 34 with respect to the torsion shaft 24 is suppressed, and the increase or decrease in the amount of threading of the right end of the screw shaft 34 onto the circumferential surface of the screw hole 24C is suppressed.

[0032] A long, rod-shaped metal wire 36 (see FIGS. 2, 5A, and 5B) is provided on the spool 16 as a second energy-absorbing member (long member), and the wire 36 has a circular cross section. A base end 36A of the wire 36 has an expanded diameter, and the vicinity of the base end 36A of the wire 36 is passed through the pinion 30, and the base end 36A of the wire 36 is engaged with the pinion 30 from the left side.

[0033] The portion of the wire 36 from the vicinity of the base end 36A to the tip side is an arrangement portion 36B, and the portion of the wire 36 between the vicinity of the base end 36A and the arrangement portion 36B is curved so that the arrangement portion 36B is arranged in the guide groove 18 of the spool 16. The arrangement portion 36B extends from the base end 36A side in the pull-out direction, and the arrangement portion 36B is sandwiched between the pinion 30 and the bottom surface of the guide groove 18.

[0034] The portion of the wire 36 distal from the placement portion 36B is an extension portion 36C, and the end of the extension portion 36C on the placement portion 36B side is curved portion 36D, so that the extension portion 36C is inserted into the insertion hole 20 of the spool 16 and extends to the right. The curved portion 36D is fitted (abuts) against the deformation surface 20A of the spool 16, and the extension portion 36C is press-fit into the insertion hole 20 and crushed by the circumferential surface of the insertion hole 20. The distal end of the extension portion 36C opposite the placement portion 36B is formed into a substantially conical shape, and the distal end of the extension portion 36C coaxially reduces in diameter as it approaches the distal end of the extension portion 36C.

[0035] The wire 36 is wound between the pinion 30 and the spool 16 (insertion hole 20 ) from the base end 36 A to the extension portion 36 C, and the wire 36 limits the relative rotation between the pinion 30 and the spool 16 .

[0036] A sensor mechanism (not shown) is provided on the left side of the cover plate 14, and the sensor mechanism is connected to the lock plate 32B of the lock base 32. In the event of a vehicle collision (a vehicle emergency such as sudden deceleration of the vehicle or sudden unwinding of the webbing 22 from the spool 16), the sensor mechanism is activated and the lock plate 32B is rotated radially outward of the lock base 32, whereby the lock plate 32B meshes with the ratchet teeth 14B of the cover plate 14 (ratchet hole 14A), restricting (locking) rotation of the lock base 32 in the unwinding direction (rotation of the lock base 32 in the retracting direction is permitted). This restricts rotation of the pinion 30 in the unwinding direction, and the wire 36 restricts rotation of the spool 16 in the unwinding direction.

[0037] The webbing retractor 10 is provided with a pretensioner mechanism 38, and when a vehicle collision is detected, a gas generator in the pretensioner mechanism 38 instantaneously generates high-pressure gas in a cylinder, and the piston in the cylinder is moved out of the cylinder by the pressure of the gas, causing the piston to engage with the pinion 30 and the pinion teeth 30B, 32A of the lock base 32 (for example, the pinion teeth 30B, 32A bite into the piston), transmitting a rotational force in the retraction direction to the pinion 30 and the lock base 32.

[0038] Next, the operation of this embodiment will be described.

[0039] In the webbing take-up device 10 configured as described above, the webbing 22 is pulled out from the spool 16 and attached to the occupant. Furthermore, the spool 16 is rotated in the retraction direction by the biasing force of the power spring of the biasing mechanism 28, and the webbing 22 is retracted onto the spool 16, thereby removing slack from the webbing 22 attached to the occupant.

[0040] When a vehicle collision is detected, in the pretensioner mechanism 38, the piston is moved by the pressure of high-pressure gas, transmitting a rotational force in the winding direction to the pinion 30 and the lock base 32. Therefore, the wire 36 restricts the relative rotation of the pinion 30 and the lock base 32 in the winding direction with respect to the spool 16, and the spool 16 rotates in the winding direction together with the pinion 30 and the lock base 32, thereby winding the webbing 22 onto the spool 16 and increasing the restraining force of the webbing 22 on the occupant.

[0041] Furthermore, in the event of a vehicle collision, the sensor mechanism is activated and the lock plate 32B of the lock base 32 meshes with the ratchet teeth 14B of the cover plate 14 (ratchet hole 14A), restricting rotation of the lock base 32 in the pull-out direction and restricting rotation of the pinion 30 in the pull-out direction. As a result, the wire 36 restricts rotation of the spool 16 in the pull-out direction, restricting pull-out of the webbing 22 from the spool 16, and the occupant is restrained by the webbing 22.

[0042] With the rotation of the lock base 32 and pinion 30 in the pull-out direction restricted, when the occupant applies a pull-out force from the spool 16 to the webbing 22, causing a rotational force in the pull-out direction to act on the spool 16, a bending force (a bending force in the winding direction due to the pull-out from the insertion hole 20 of the spool 16 and a bending force that returns the bend) is applied to the extension portion 36C of the wire 36 at the deformation surface 20A of the spool 16.

[0043] When the pulling load from the spool 16 from the occupant to the webbing 22 (rotational load in the unwinding direction of the spool 16) is equal to or greater than the bending load resistance F1 (second force limiter load) of the wire 36 (see FIG. 11 ), the extending portion 36C of the wire 36 is sequentially bent (squeezed) at the deformation surface 20A while being unwound from the insertion hole 20 (see FIGS. 6A , 6B , 7A , 7B , 8A , 8B , 9A and 9B ), thereby allowing rotation of the spool 16 in the unwinding direction relative to the lock base 32 and the pinion 30 and allowing the webbing 22 to be unwound from the spool 16. As a result, the kinetic energy of the occupant is absorbed by the bending deformation of the wire 36, and the occupant is protected.

[0044] When rotation of the spool 16 in the pull-out direction is permitted, the torsion shaft 24 rotates integrally with the spool 16 in the pull-out direction, and the second convex portion 24B of the torsion shaft 24 moves in the pull-out direction relative to the second concave portion 30A of the pinion 30. Furthermore, when the second convex portion 24B abuts against the end surface of the second concave portion 30A on the pull-out direction side (see FIGS. 10A and 10B), rotation of the torsion shaft 24 in the pull-out direction is restricted, and not only the wire 36 but also the torsion shaft 24 restricts rotation of the spool 16 in the pull-out direction, and a torsional force is applied to the torsion shaft 24.

[0045] Then, when the pulling load from the spool 16 from the occupant to the webbing 22 (rotational load in the unwinding direction of the spool 16) is equal to or greater than the total load of the bending resistance load F1 of the wire 36 and the torsional resistance load F2 (first force limiter load) of the torsion shaft 24 (see FIG. 11 ), the extending portion 36C of the wire 36 is pulled out of the insertion hole 20 and is sequentially bent (squeezed) at the deformation surface 20A, and the torsion shaft 24 is twisted, which allows rotation of the spool 16 in the unwinding direction relative to the lock base 32 and the pinion 30 and allows the webbing 22 to be pulled out from the spool 16. As a result, the kinetic energy of the occupant is absorbed by the bending deformation of the wire 36 and the torsional deformation of the torsion shaft 24, and the occupant is protected.

[0046] Furthermore, after the extension portion 36C of the wire 36 has finished being pulled out from the insertion hole 20 and the bending deformation of the extension portion 36C has finished, when the pulling load from the spool 16 from the occupant to the webbing 22 (the rotational load in the pull-out direction of the spool 16) is equal to or greater than the torsional load resistance F2 of the torsion shaft 24 (see FIG. 11 ), the torsion shaft 24 is torsionally deformed, allowing the spool 16 to rotate in the pull-out direction relative to the lock base 32 and the pinion 30, and allowing the webbing 22 to be pulled out from the spool 16. As a result, the kinetic energy of the occupant is absorbed by the torsional deformation of the torsion shaft 24, and the occupant is protected.

[0047] Here, the load on the spool 16 required for the wire 36 to bend and deform to allow rotation of the spool 16 in the unwinding direction (the maximum load of the bending load resistance F1 of the wire 36 in FIG. 11 ) is set higher than the load on the spool 16 required for the torsion shaft 24 to be twisted and allow rotation of the spool 16 in the unwinding direction (the maximum load of the torsion load resistance F2 of the torsion shaft 24 in FIG. 11 ). Therefore, when a rotational force in the winding direction is transmitted to the pinion 30 and the lock base 32 by the pretensioner mechanism 38, the wire 36 can effectively limit the relative rotation of the pinion 30 and the lock base 32 in the winding direction with respect to the spool 16, effectively suppressing torsional deformation of the torsion shaft 24. This prevents the energy of the pretensioner mechanism 38 for rotating the spool 16 in the winding direction from being lost due to torsional deformation of the torsion shaft 24.

[0048] Furthermore, the bending load resistance of the wire 36 against the rotational force in the winding direction transmitted to the pinion 30 and the lock base 32 by the pretensioner mechanism 38 (a load similar to the maximum load of the bending load resistance F1 of the wire 36 in FIG. 11 ) is set higher than the torsion load resistance of the torsion shaft 24 against the rotational force in the winding direction transmitted to the pinion 30 and the lock base 32 by the pretensioner mechanism 38 (a load similar to the maximum load of the torsion load resistance F2 of the torsion shaft 24 in FIG. 11 when the torsion shaft 24 is connected to the pinion 30 so as to be rotatable together with the pinion 30). Therefore, when a rotational force in the winding direction is transmitted to the pinion 30 and the lock base 32 by the pretensioner mechanism 38, the wire 36 can effectively limit the relative rotation of the pinion 30 and the lock base 32 in the winding direction with respect to the spool 16, and torsional deformation of the torsion shaft 24 can be effectively suppressed.

[0049] Furthermore, when rotation of the spool 16 in the pull-out direction is permitted (see FIG. 11 ), the torsion shaft 24 begins to twist (see FIGS. 9A , 9B , 10A and 10B ) when the bending load resistance F1 of the wire 36 (the load required to bend and deform the wire 36) is reduced (when the bending deformation of the wire 36 is completed). Therefore, by lowering the torsional load resistance F2 at the start of torsional deformation of the torsion shaft 24, fluctuations in the force limiter load (the load required to be able to rotate the spool 16 in the pull-out direction) can be suppressed.

[0050] Furthermore, a base end 36A of the wire 36 is engaged with the pinion 30 from the left side, and an extension portion 36C of the wire 36 is press-fit into the insertion hole 20 of the spool 16 and is crushed (deformed) by the circumferential surface of the insertion hole 20. This prevents the extension portion 36C from rattling left and right relative to the insertion hole 20, thereby preventing rattling left and right between the pinion 30 and the spool 16. Furthermore, when the pinion 30 and the wire 36 are assembled to the spool 16, the wire 36 is pressed between the spool 16 and the pinion 30, thereby preventing rattling of the pinion 30 toward the spool 16.

[0051] Furthermore, the right end face of the screw shaft 34 comes into contact with the bottom surface of the threaded hole 24C of the torsion shaft 24, restricting movement of the screw shaft 34 toward the torsion shaft 24 (right side), and allowing the lock base 32 to move away to the right from the expanded diameter portion 34A of the screw shaft 34. Therefore, when the torsion shaft 24 and the screw shaft 34 rotate integrally with the spool 16 in the unwinding direction relative to the lock base 32, friction between the expanded diameter portion 34A and the lock base 32 can be suppressed, and the load at which the webbing 22 is allowed to be unwound from the spool 16 can be prevented from increasing due to friction between the expanded diameter portion 34A and the lock base 32.

[0052] Furthermore, the longitudinal dimension of the wire 36 (particularly the extension portion 36C) is set to the minimum dimension necessary to limit the relative rotation of the pinion 30 and the lock base 32 with respect to the spool 16 in the winding direction when the pretensioner mechanism 38 is activated. This allows the wire 36 to be made compact.

[0053] In the present embodiment, the bottom surface of the screw hole 24C of the torsion shaft 24 is concave. However, the bottom surface of the screw hole 24C of the torsion shaft 24 may be flat, and the right end surface of the screw shaft 34 may be in surface contact with the bottom surface of the screw hole 24C.

[0054] Furthermore, in this embodiment, an intermediate material (for example, grease) may be provided between the enlarged diameter portion 34A of the screw shaft 34 and the lock base 32 to reduce the frictional force between the enlarged diameter portion 34A and the lock base 32.

[0055] In addition, in the present embodiment, the second convex portion 24B of the torsion shaft 24 is movable in the pull-out direction relative to the second concave portion 30A of the pinion 30, allowing the spool 16 to rotate a predetermined amount in the pull-out direction relative to the pinion 30. However, the first concave portion 16A of the spool 16 may be movable in the pull-out direction relative to the first convex portion 24A of the torsion shaft 24, allowing the spool 16 to rotate a predetermined amount in the pull-out direction relative to the pinion 30.

[0056] Second Embodiment FIG. 12A shows a cross-sectional view of the main part of a webbing take-up device 50 according to a second embodiment of the present invention.

[0057] The webbing take-up device 50 according to this embodiment has substantially the same configuration as that of the first embodiment, but differs in the following respects.

[0058] The webbing take-up device 50 according to this embodiment does not include the cover plate 14 in the first embodiment.

[0059] As shown in Figure 12A, a predetermined number (three in this embodiment) of curved rectangular column-shaped first recesses 16A (see Figures 14A and 14B) are formed on the peripheral surface of the right side of the spool 16, and the predetermined number of first recesses 16A extend in the axial direction of the spool 16 and are arranged at intervals around the circumferential direction of the spool 16.

[0060] A predetermined number (three in this embodiment) of trapezoidal columnar first protrusions 24A (see FIGS. 13 and 14A) are integrally formed on the circumferential surface of the right end of the torsion shaft 24. The predetermined number of first protrusions 24A extend in the axial direction of the torsion shaft 24 and are spaced apart circumferentially about the torsion shaft 24. The first protrusions 24A are inserted into first recesses 16A of the spool 16, and the dimension of the first recesses 16A in the circumferential direction of the spool 16 is larger than the dimension of the first protrusions 24A in the circumferential direction of the torsion shaft 24. The end face of the first recesses 16A on the side facing the unwinding direction abuts against the first protrusions 24A, allowing the spool 16 to rotate a predetermined amount relative to the torsion shaft 24 in the unwinding direction but preventing it from rotating relative to the torsion shaft 24 in the winding direction. A specific number (six in this embodiment) of trapezoidal columnar second convex portions 24B (see Figure 13) are integrally formed on the peripheral surface of the left side of the torsion shaft 24, and a specific number of first convex portions 24A extend in the axial direction of the torsion shaft 24 and are arranged at intervals in the circumferential direction of the torsion shaft 24.

[0061] A metal, approximately disk-shaped push stopper 52 (see Figures 13 and 14B) serving as a low-friction member is attached to the right end face of the torsion shaft 24, and when the spool 16 rotates relative to the torsion shaft 24 in the pull-out direction, the push stopper 52 prevents the right end face of the torsion shaft 24 from generating a frictional force (rotational resistance force) against the spool 16.

[0062] A specific number (six in this embodiment) of curved rectangular column-shaped second recesses 30A are formed on the circumferential surface of the lock base 32 (see FIGS. 12B and 13 ). The specific number of second recesses 30A extend in the axial direction of the lock base 32 and are spaced apart circumferentially around the lock base 32. The left side of the torsion shaft 24 is coaxially inserted into the lock base 32, and the second protrusion 24B of the torsion shaft 24 is fitted into the second recess 30A. This connects the left side of the torsion shaft 24 to the lock base 32 so that it can rotate integrally with the lock base 32, allowing the torsion shaft 24 to rotate integrally with the lock base 32. The lock base 32 is a ratchet gear (lock gear), and ratchet teeth 14B are formed around the entire outer periphery of the lock base 32. The lock plate 32B is rotatably supported by the leg plate 12A of the frame 12 in place of the lock base 32.

[0063] The pinion 30 (not shown) is arranged coaxially on the left side of the lock base 32 , and the pinion 30 is rotatable integrally with the lock base 32 .

[0064] The vicinity of the base end 36A of the wire 36 (see FIGS. 12B and 13) passes through the lock base 32, and the base end 36A of the wire 36 is engaged with the lock base 32 from the left side.

[0065] Incidentally, when a vehicle collision is detected, in the pretensioner mechanism 38, the piston is moved by the pressure of high-pressure gas and transmits a rotational force in the winding direction to the lock base 32 via the pinion 30 (pinion teeth 30B). Therefore, the wire 36 restricts the relative rotation of the lock base 32 with respect to the spool 16 in the winding direction, and the spool 16 rotates in the winding direction together with the lock base 32, whereby the webbing 22 is wound onto the spool 16 and the restraining force of the webbing 22 on the occupant is increased.

[0066] Furthermore, in the event of a vehicle collision, the sensor mechanism is activated and the lock plate 32B of the frame 12 meshes with the ratchet teeth 14B of the lock base 32, restricting rotation of the lock base 32 in the pull-out direction. As a result, the wire 36 restricts rotation of the spool 16 in the pull-out direction, restricting pull-out of the webbing 22 from the spool 16, and the occupant is restrained by the webbing 22.

[0067] With the rotation of the lock base 32 in the pull-out direction restricted, when the occupant applies a pull-out force from the spool 16 to the webbing 22, causing a rotational force in the pull-out direction to act on the spool 16, a bending force (a bending force in the winding direction due to the pull-out from the insertion hole 20 of the spool 16 and a bending force that returns the bend) is applied to the extension portion 36C of the wire 36 at the deformation surface 20A of the spool 16.

[0068] When the pulling load from the spool 16 from the occupant to the webbing 22 (rotational load in the unwinding direction of the spool 16) is equal to or greater than the bending load resistance F1 (second force limiter load) of the wire 36 (see FIG. 11 ), the extending portion 36C of the wire 36 is sequentially bent (squeezed) at the deformation surface 20A while being unwound from the insertion hole 20, thereby allowing rotation of the spool 16 in the unwinding direction relative to the lock base 32 and allowing the webbing 22 to be unwound from the spool 16. As a result, the kinetic energy of the occupant is absorbed by the bending deformation of the wire 36, and the occupant is protected.

[0069] When rotation of the spool 16 in the unwinding direction is permitted, the spool 16 rotates in the unwinding direction relative to the torsion shaft 24, and the first recess 16A of the spool 16 moves in the unwinding direction relative to the first protrusion 24A of the torsion shaft 24. Furthermore, when the end face of the first recess 16A on the winding direction side abuts against the first protrusion 24A, not only the wire 36 but also the torsion shaft 24 restricts the rotation of the spool 16 in the unwinding direction, and a torsional force is applied to the torsion shaft 24.

[0070] Then, when the pulling load from the spool 16 from the occupant to the webbing 22 (rotational load in the unwinding direction of the spool 16) is equal to or greater than the total load of the bending resistance load F1 of the wire 36 and the torsional resistance load F2 (first force limiter load) of the torsion shaft 24 (see FIG. 11 ), the extending portion 36C of the wire 36 is pulled out of the insertion hole 20 and is sequentially bent (squeezed) at the deformation surface 20A, and the torsion shaft 24 is twisted, which allows rotation of the spool 16 in the unwinding direction relative to the lock base 32 and allows the webbing 22 to be pulled out from the spool 16. As a result, the kinetic energy of the occupant is absorbed by the bending deformation of the wire 36 and the torsional deformation of the torsion shaft 24, and the occupant is protected.

[0071] Furthermore, after the extension portion 36C of the wire 36 has finished being pulled out from the insertion hole 20 and the bending deformation of the extension portion 36C has finished, when the pulling load from the spool 16 from the occupant to the webbing 22 (the rotational load in the pull-out direction of the spool 16) is equal to or greater than the torsional load resistance F2 of the torsion shaft 24 (see FIG. 11 ), the torsion shaft 24 is torsionally deformed, allowing the spool 16 to rotate in the pull-out direction relative to the lock base 32 and allowing the webbing 22 to be pulled out from the spool 16. As a result, the kinetic energy of the occupant is absorbed by the torsional deformation of the torsion shaft 24, and the occupant is protected.

[0072] Here, this embodiment can also achieve the same functions and effects as the first embodiment.

[0073] In particular, the base end 36A of the wire 36 is engaged with the lock base 32 from the left side, and the extending portion 36C of the wire 36 is press-fit into the insertion hole 20 of the spool 16 and is crushed (deformed) by the circumferential surface of the insertion hole 20. This prevents the extending portion 36C from rattling left and right relative to the insertion hole 20, thereby preventing rattling left and right between the lock base 32 and the spool 16, and also prevents rattling of the lock base 32 toward the spool 16 because the wire 36 is pressed between the spool 16 and the lock base 32 when the lock base 32 and the wire 36 are assembled to the spool 16.

[0074] In this embodiment, the first recess 16A of the spool 16 is movable in the pull-out direction relative to the first protrusion 24A of the torsion shaft 24, allowing the spool 16 to rotate a predetermined amount in the pull-out direction relative to the lock base 32. However, the second protrusion 24B of the torsion shaft 24 may be movable in the pull-out direction relative to the second recess 30A of the lock base 32, allowing the spool 16 to rotate a predetermined amount in the pull-out direction relative to the lock base 32.

[0075] Furthermore, in the first and second embodiments described above, the load on the spool 16 that is applied when the wire 36 is bent and deformed to allow the spool 16 to rotate in the pull-out direction is set higher than the load on the spool 16 that is applied when the torsion shaft 24 is twisted and deformed to allow the spool 16 to rotate in the pull-out direction. However, the load on the spool 16 that is applied when the wire 36 is bent and deformed to allow the spool 16 to rotate in the pull-out direction may be set equal to the load on the spool 16 that is applied when the torsion shaft 24 is twisted and deformed to allow the spool 16 to rotate in the pull-out direction.

[0076] Furthermore, in the first and second embodiments described above, the bending load resistance of the wire 36 against the rotational force in the winding direction transmitted to the pinion 30 and the lock base 32 by the pretensioner mechanism 38 is made higher than the torsional load resistance of the torsion shaft 24 against the rotational force in the winding direction transmitted to the pinion 30 and the lock base 32 by the pretensioner mechanism 38. However, the bending load resistance of the wire 36 against the rotational force in the winding direction transmitted to the pinion 30 and the lock base 32 by the pretensioner mechanism 38 may be made the same as the torsional load resistance of the torsion shaft 24 against the rotational force in the winding direction transmitted to the pinion 30 and the lock base 32 by the pretensioner mechanism 38.

[0077] The disclosure of Japanese Patent Application No. 2024-100593, filed on June 21, 2024, is incorporated herein by reference in its entirety.

[0078] 10...Webbing take-up device, 16...Spool, 22...Webbing, 24...Torsion shaft (deformable member), 30...Pinion (regulating body), 32...Lock base (regulating body), 34...Screw shaft (locking member), 34A...Expanded diameter portion (locking portion), 36...Wire (long material), 50...Webbing take-up device

Claims

1. A webbing take-up device comprising: a spool around which a webbing to be worn by an occupant is rotated in a take-up direction to be taken up, and around which the webbing is unwound and rotated in the unwound direction; a restrictor that can transmit a rotational force in the take-up direction and restrict rotation in the unwound direction; a long material that, when the rotational force in the take-up direction is transmitted to the restrictor, restricts the relative rotation of the restrictor with respect to the spool in the take-up direction, thereby transmitting the rotational force in the take-up direction to the spool, and when the rotation of the restrictor in the unwound direction is restricted, moves in the longitudinal direction and is bent and deformed, thereby allowing rotation of the spool in the unwound direction; and a deformable member that, when the rotation of the restrictor in the unwound direction is restricted, is torsionally deformed, allowing rotation of the spool in the unwound direction, and the load on the spool for bending and deforming the long material to allow rotation of the spool in the unwound direction is made equal to or higher than the load on the spool for torsionally deforming the long material to allow rotation of the spool in the unwound direction.

2. A webbing take-up device comprising: a spool around which a webbing worn by an occupant is rotated in a take-up direction to be taken up, and around which the webbing is unwound and rotated in the unwound direction; a restricting body that can transmit a rotational force in the take-up direction and can restrict rotation in the unwound direction; a long material that, when the rotational force in the take-up direction is transmitted to the restricting body, restricts the relative rotation of the restricting body with respect to the spool in the take-up direction, thereby transmitting the rotational force in the take-up direction to the spool, and when the rotation of the restricting body in the unwound direction is restricted, is moved in the longitudinal direction and bent and deformed, thereby allowing rotation of the spool in the unwound direction; and a deforming member that, when the rotation of the restricting body in the unwound direction is restricted, is torsionally deformed, allowing rotation of the spool in the unwound direction, and which begins to torsionally deform when the load for bending and deforming the long material is reduced when rotation of the spool in the unwound direction is allowed.

3. A webbing take-up device according to claim 1 or 2, wherein the long material is engaged with the restricting body and is disposed on the spool in a state where it is deformed by the spool.

4. A webbing retractor according to any one of claims 1 to 3, wherein the bending load resistance of the elongated material against the rotational force in the winding direction transmitted to the regulating body is made equal to or higher than the torsional load resistance of the deformable member against the rotational force in the winding direction transmitted to the regulating body.

5. A webbing take-up device as set forth in any one of claims 1 to 4, comprising a locking member that is provided with a locking portion and is assembled to the deformable member to restrict movement of the locking portion toward the deformable member, thereby positioning the regulating body between the locking portion and the spool and allowing the regulating body to be separated from the locking portion.

6. A webbing take-up device according to any one of claims 1 to 5, wherein the deformable member allows the spool to rotate a predetermined amount in the unwinding direction relative to the restricting body.

7. A webbing take-up device according to any one of claims 1 to 6, comprising an insertion hole into which the long material is inserted and through which the unwinding of the long material ends after the long material is unwound and bent.

8. A webbing take-up device according to any one of claims 1 to 7, wherein a rotational force in the take-up direction is transmitted to the regulating body by gas pressure.

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