Belt winding device

Abstract

Belt winding device (10) with: a spool (14) on which a belt (16) to be applied to a vehicle occupant is wound up due to rotation of the spool (14) in a winding direction; a first rotor (22, 40) rotatable together with the spool (14), the first rotor (22, 40) having a first engagement tooth (22F, 40A) with which a moving moving element (38) engages, the first rotor (22, 40) being rotated as a result of the moving moving element (38) engaging the first engagement tooth (22F, 40A); and a second rotor (24, 42) rotatable together with the spool (14), the second rotor (24, 42) having a second engagement tooth (24H, 42A) with which the moving member (38) engages, the second engagement tooth (24H, 42A) being arranged to overlap with the first engagement tooth (22F, 40A) in a rotational circumferential direction of the first rotor (22, 40), and the second rotor (24, 42) being rotated as a result of the moving member (38) engaging the second engagement tooth (24H, 42A).

Description

Technical area

[0001] The present invention relates to a belt winding device. Background of the state of the art

[0002] Japanese Patent Application JP 2014-500178 discloses a belt retractor equipped with a pretensioning mechanism that winds a belt around a spool by rotating the spool in a winding direction at the time of a vehicle emergency. In the pretensioning mechanism disclosed in Japanese Patent Application JP 2014-500178, the belt can be wound around the spool by a moving member that is moved by actuation of a gas generator, engaging with a plurality of engagement teeth of a rotor.

[0003] In a structure in which a moving element is moved in engagement with a plurality of meshing teeth and in which the kinetic energy of the moving element is transmitted to a coil, it is important to ensure the strength of the many meshing teeth. SUMMARY OF THE INVENTIONTechnical Problem

[0004] The present invention provides a belt take-up device that can ensure the strength of an engagement tooth with which a moving member engages. Solution to the problem

[0005] A first aspect of the present invention is a belt retractor comprising (i) a spool on which a belt to be fastened to a vehicle occupant is wound due to rotation of the spool in a winding direction; (ii) a first rotor rotatable together with the spool, the first rotor having a first engagement tooth with which a moving moving member engages, the first rotor being rotated as a result of the moving moving member engaging the first engagement tooth;and (iii) a second rotor rotatable together with the spool, the second rotor having a second engagement tooth with which the moving member engages, the second engagement tooth being arranged to overlap with the first engagement tooth in a rotational circumferential direction of the first rotor, and the second rotor being rotated as a result of the moving member engaging the second engagement tooth.

[0006] According to the aforementioned first aspect, the first rotor and the second rotor are rotated when the moving member moves and engages with the first engagement tooth of the first rotor and the second engagement tooth of the second rotor. Consequently, the spool is rotated in the winding direction together with the first rotor and the second rotor, and the belt is wound on the spool. In this first aspect, a portion of the second engagement tooth of the second rotor is arranged to overlap with the first engagement tooth of the first rotor in the rotational circumferential direction (the rotational circumferential direction of the first rotor and the second rotor). Thus, the first engagement tooth can be supported by the second engagement tooth, and the second engagement tooth can be supported by the first engagement tooth.Therefore, the strength of the engagement teeth with which the engagement element engages (the first engagement tooth and the second engagement tooth) can be ensured.

[0007] In a second aspect of the present invention, in the first aspect, a plurality of the first engagement teeth and a plurality of the second engagement teeth are alternately arrayed in the rotational circumferential direction of the first rotor and the second rotor.

[0008] According to the second aspect described above, the plurality of first engagement teeth of the first rotor and the plurality of second engagement teeth of the second rotor are alternately arranged in the rotational circumferential direction. Thus, the number of engagement teeth (first engagement teeth and second engagement teeth) with which the moving member can engage can be increased, and the first rotor and the second rotor can be rotated instantly when the moving member engages the engagement teeth.

[0009] In a third aspect of the present invention, in the first aspect or the second aspect, the first engagement tooth and the second engagement tooth are configured such that an overlapping area between the first engagement tooth and the second engagement tooth in the rotational circumferential direction of the first rotor and the second rotor becomes smaller toward a rotational radial direction outside of the first rotor and the second rotor.

[0010] According to the third aspect described above, the first engagement tooth and the second engagement tooth are configured such that the overlap area (overlapping area) in the rotation circumferential direction between the first engagement tooth and the second engagement tooth becomes smaller toward the outer side of the first rotor and the second rotor in the rotation radial direction. Thus, the resistance when the moving element engages the tooth tip sides (tooth end sides) of the first engagement tooth and the second engagement tooth (the outer side of the first rotor and the second rotor in the rotation radial direction) can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a sectional view of a cross section in which a belt take-up device according to a first embodiment is cut along a rotation axis direction of a spool. Fig. 2 shows a perspective view of a locking base and a connecting element which are designed as a single piece. Fig. 3 shows an enlarged perspective view of an enlargement of a locking base side engagement tooth of the locking base. Fig. 4 is a front view in which the locking base-side engagement tooth of the locking base and a link-side engagement tooth of the link are viewed from the circumferential direction side. Fig. 5A shows a side view of a first rotor. Fig. Figure 5B shows a sectional view of a cross section of the first rotor taken along a Fig. 5A is cut along line 5B-5B. Fig. Figure 6A shows a side view of a second rotor. Fig. 6B shows a sectional view of a cross section of the second rotor taken along a Fig. 6A is cut along line 6B-6B. Fig. 7A shows a side view of the first rotor and the second rotor. Fig. 7B shows a sectional view of a cross section of the first rotor and the second rotor taken along a Fig. 7A are cut along line 7B-7B. Fig. 8A shows a side view of another first rotor. Fig. Figure 8B shows a sectional view of a cross section of the first rotor taken along a Fig. 8A is cut along line 8B-8B. Fig. 9A shows a side view of another second rotor. Fig. 9B shows a sectional view of a cross section of the second rotor taken along a Fig. 9A is cut along line 9B-9B. Fig. 10A shows a side view of the first rotor and the second rotor, which are designed as one piece. Fig. 10B shows a sectional view of a cross section of the first rotor and the second rotor taken along a Fig. 10A are intersected by line 10B-10B. DESCRIPTION OF THE EMBODIMENTS

[0011] A belt winding device according to an embodiment of the present invention is described below with reference to Fig. 1 to 4. The direction of an arrow Z, the direction of an arrow R, and the direction of an arrow C shown in the drawings respectively indicate a rotational axis direction, a rotational radial direction, and a rotational circumferential direction of a spool. When simply referring to an axial direction, radial directions, and a circumferential direction below without further specific reference, these directions refer to the rotational axis direction, the rotational radial directions, and the rotational circumferential direction of the spool.

[0012] As this is Fig. As shown in Fig. 1, a webbing retractor 10 is equipped with a frame 12 made of metal. The frame 12 is fixed to a pillar constituting a vehicle body frame of a vehicle, a seat cushion frame constituting a frame of a vehicle seat, or the like. The frame 12 is provided with a foot plate 12A and a foot plate 12B arranged to be spaced apart in the axial direction and opposed to each other. Circular insertion holes 12C and 12D are formed in the foot plate 12A and the foot plate 12B. Portions of a spool 14, which will be described later, are inserted through the insertion holes 12C and 12D.

[0013] The spool 14 is made of metal and formed in a substantially circular tubular shape, with the larger part of it being disposed between the base plate 12A and the base plate 12B of the frame 12. A journal portion 14A is provided at an end portion on another axial direction end side of the spool 14 (the opposite side to the direction of arrow Z). A bearing portion 18A is provided on a bearing housing 18, which will be described later. The journal portion 14A is supported on the bearing portion 18A via a coil spring anchor member 32. The spool 14 is further provided with a take-up portion 14B on which a belt 16 is wound. The belt 16 is formed in a long, narrow belt shape, and a longitudinally viewed base end portion of the belt 16 is anchored to the take-up portion 14B.When the spool 14 is rotated in a winding direction (the direction of an arrow C), the belt 16 is wound on the winding portion 14B of the spool 14 starting from its longitudinal base end side. When the belt 16 is pulled out (unplugged) from the spool 14, the spool 14 is rotated in a pull-out direction (the opposite direction to arrow C). A torsion shaft insertion hole 14C is formed in an axial center portion of the spool 14. A torsion shaft 26 described below is inserted into the torsion shaft insertion hole 14C. One axial direction side of the torsion shaft insertion hole 14C is open, and the other axial direction side of the torsion shaft insertion hole 14C is closed.

[0014] A longitudinally distal end of the belt 16 extends from the spool 14 to the vehicle upper side. The longitudinally distal end of the belt 16 passes through a slotted hole formed in a through-anchor (not shown in the drawings) on the vehicle upper side of the frame 12 and returns to the vehicle lower side.

[0015] The longitudinally distal end side of the belt 16 is anchored to an anchor plate (not shown in the drawings). The anchor plate is formed of a metal sheet made of steel or the like and is fixed to a floor portion of the vehicle (not shown in the drawings), a frame member of a seat (not shown in the drawings) corresponding to the present belt retractor 10, or the like.

[0016] A seatbelt device for a vehicle to which the present belt retractor 10 is applied is equipped with a buckle device (not shown in the drawings). The buckle device is provided on an inner side, as viewed in the vehicle width direction, of the seat to which the present belt retractor is applied. In a state where the belt 16 is wound around the body of a vehicle occupant sitting on the seat, a tongue (not shown in the drawings) provided on the belt 16 engages with the buckle device. Thus, the belt 16 is wound on the body of the vehicle occupant.

[0017] The spring housing 18, made of plastic, has the aforementioned bearing portion 18A. The spring housing 18 is provided on an outer surface side of the base plate 12A of the frame 12 (outer side of the frame 12). A coil spring (not shown in the drawings) is provided inside the spring housing 18. One end portion of the coil spring is anchored to the coil spring anchoring member 32 made of plastic. The spool 14 is urged in the winding direction (the direction of arrow C) by an urging force of the coil spring.

[0018] Furthermore, a locking mechanism 20 is provided on an outer surface side of the base plate 12B of the frame 12 (outer side of the frame 12). The locking mechanism 20 is provided with a locking base 22 made of metal and constituting a portion of a rotor, and a locking claw 28 made of metal and supported on the locking base 22. The locking base 22 is provided coaxially with the spool 14 on an axial direction side relative to the spool 14. The locking base 22 is connected to the spool 14 via a metal-made connecting member 24 constituting another portion of the rotor, and the torsion shaft 26. Thus, the locking base 22 can be rotated integrally with the spool 14.

[0019] The locking mechanism 20 is equipped with a sensor device (not shown in the drawings). The sensor device is activated (actuated) at the time of a vehicle emergency, such as during a vehicle collision, during sudden deceleration, or the like. When the sensor device is activated, the rotation of the locking base 22 in the pull-out direction (the pull-out direction of the spool 14) is limited, as described in more detail below.

[0020] A cover plate 30 made of metal is fixed to the base plate 12B of the frame 12. The cover plate 30 and the base plate 12B of the frame 12 form a support housing portion (rail housing portion) 34 in which a large portion of the locking base 22 and the connecting member 24 are arranged.

[0021] The cover plate 30 is provided with a plate portion 30A that is recessed toward the side opposite the side where the frame 12 is disposed. The plate portion 30A is arranged to face the base plate 12B of the frame 12 in the axial direction. A locking hole 30B is formed to penetrate the plate portion 30A.

[0022] The locking base 22 of the locking mechanism 20 penetrates the locking hole 30B of the cover plate 30. When the sensor device of the locking mechanism 20 is activated (operated) and the locking claw 28 attached to the locking base 22 moves toward the radially outer side of the locking base 22, the locking claw 28 meshes with locking teeth of the locking hole 30B of the cover plate 30. As a result, the rotation of the locking base 22 in the pull-out direction is limited. Consequently, the rotation in the pull-out direction of the spool 14, which is connected to the locking base 22 via the connecting member 24 and the torsion shaft 26, is limited.

[0023] The belt take-up device 10 is further equipped with the torsion shaft 26. The torsion shaft 26 is formed in a rod shape, is housed in the torsion shaft insertion hole 14C of the spool 14, and is arranged along the longitudinal direction of the spool 14. An end portion 26A on one side of the torsion shaft 26 is anchored to the spool 14. An end portion 26B on another side of the torsion shaft 26 is anchored to the connecting member 24 and thus connected to the locking base 22. When the rotation of the locking base 22 in the pull-out direction is restricted (limited), a longitudinally central portion of the torsion shaft 26 is deformed by twisting. Thus, rotation of the belt 16 in the pull-out direction of the spool 14 is tolerated.

[0024] The detailed structure of the locking base 22 serving as a first rotor and the connecting member 24 serving as a second rotor will be described below.

[0025] The locking base 22 is provided with a locking base-side flange portion 22A formed in a circular plate shape (circular plate shape) having a thickness direction in the axial direction and extending in the radial directions. The locking base 22 is further provided with a circular column portion (circular column portion) 22B having a substantially circular column shape. The circular column portion 22B protrudes toward an axial direction side from the locking base-side flange portion 22A, and a portion where the locking claw 28 is disposed is cut away from the circular column portion 22B. A rod-shaped shaft portion 22C protrudes toward the one direction side from the axial center portion of the circular column portion 22B. A locking mechanism housing cover 36 is attached to the cover plate 30.The shaft portion 22C is inserted into a bearing hole 36A formed in the locking mechanism housing cover 36. Thus, the shaft portion 22C is supported on an inner peripheral side of the bearing hole 36A.

[0026] The locking base 22 is provided with a locking base-side tube portion 22D protruding toward the other axial direction side from the locking base-side flange portion 22A. The locking base-side tube portion 22D is formed such that an outer diameter of a radially outer side thereof decreases toward the other axial direction side. A locking base-side spline (key) 22E in a spline shape (key shape, profile shape) is formed on an inner peripheral portion of the locking base-side tube portion 22D. The locking base 22 is further provided with a plurality of locking base-side engagement teeth 22F serving as first engagement teeth.The locking base-side engagement teeth 22F protrude toward the radially outer side and the other axial direction side from the locking base-side tube portion 22D and the locking base-side flange portion 22A and are arranged at a predetermined interval in the circumferential direction. A locking base-side core portion 22G is provided at an axial center portion of the locking base-side tube portion 22D. The locking base-side core portion 22G is formed in a tubular shape with a larger diameter than the shaft portion 22C.

[0027] The connecting member 24 is provided with a connecting-member-side flange portion 24A formed in a circular plate shape having a thickness direction in the axial direction and extending in the radial directions. The connecting member 24 is further provided with a torsion shaft engagement portion 24B formed in a circular tube shape. The torsion shaft engagement portion 24B protrudes to the other axial direction side from the connecting-member-side flange portion 24A. A spline-shaped (wedge-shaped) torsion shaft engagement tooth (spline) 24C is formed on an inner peripheral portion of the torsion shaft engagement portion 24B. The end portion 26B on the other side of the torsion shaft 26 engages with the torsion shaft engagement tooth 24C.

[0028] The connecting member 24 is provided with a connecting member-side tube portion 24D protruding toward one axial direction side from the connecting member-side flange portion 24A. The connecting member-side tube portion 24D is formed such that an outer diameter of its outer side surface, viewed in the radial direction, decreases toward one axial direction side. A connecting member-side core portion 24F is provided on an inner peripheral portion of the connecting member-side tube portion 24D. A connecting member-side spline (key) 24E in a spline shape (key shape, profile shape) is formed on the connecting member-side core portion 24F. The connecting element side toothing 24E protrudes to one axial direction side, and an outer peripheral portion of the connecting element side toothing 24E engages with the locking base side toothing 22E of the locking base 22.An insertion hole 24G is formed at an axial center portion of the link-side core portion 24F. The lock-base-side core portion 22G of the lock base 22 is inserted into the insertion hole 24G. The lock base 22 and the link 24 are connected to be integrally rotatable by inserting the lock-base-side core portion 22G of the lock base 22 into the insertion hole 24G of the link-side core portion 24F and engaging the link-side serration 24E with the lock-base-side serration 22E. In the present embodiment, the distal end portion of the lock-base-side core portion 22G of the lock base 22 is caulked (flattened) so that the connection of the lock base 22 and the link 24 does not disengage.

[0029] The connecting element 24 is further provided with a plurality of connecting element-side engagement teeth 24H serving as second engagement teeth. The connecting element-side engagement teeth 24H protrude toward the radially outer side and one axial direction side of the connecting element-side pipe portion 24D and the connecting element-side flange portion 24A and are arranged at a predetermined interval in the circumferential direction. As shown in Fig. 2, in the state where the lock base 22 and the link 24 are connected, the lock base side engagement teeth 22F and the link side engagement teeth 24H are alternately arranged in the circumferential direction and arranged at equal intervals.

[0030] As this is Fig. As shown in Fig. 1, a carrier (rail) 38 serving as a moving member engages with the link-side engaging teeth 24H and the lock-base-side engaging teeth 22F. The carrier 38 is formed in a rod shape (bar shape) from a material softer than the lock base 22 and the link 24 (for example, synthetic resin). The carrier 38 is arranged inside a pipe not shown in the drawings. At the time of a vehicle emergency, the carrier 38 is moved inside the pipe and inside the cover plate 30 (inside the carrier accommodating portion 34) by pressure from the gas generated by a micro gas generator not shown in the drawings, and the carrier 38 engages with the link-side engaging teeth 24H and the lock-base-side engaging teeth 22F.As a result, the locking base 22 and the connecting member 24 are rotated to a circumferential direction side (the side shown by the arrow C), and the spool 14 connected to the locking base 22 and the connecting member 24 via the torsion shaft 26 is rotated in the winding direction.

[0031] Next, the details of the structure of the lock base side engagement teeth 22F of the lock base 22 and the link side engagement teeth 24H of the link 24, which are main portions of the present embodiment, will be described.

[0032] As this is Fig. 1, the lock base side engagement teeth 22F and the link side engagement teeth 24H are symmetrical about a bisection line L1 that bisects (divides into two halves) the space between the lock base side flange portion 22A and the link side flange portion 24A in the axial direction.

[0033] As this is the case in the Fig. 1 and Fig. 3, a circumferential dimension of each locking base-side engagement tooth 22F decreases steadily toward its radially outer side. In addition, a region on the other axial direction side of the locking base-side engagement tooth 22F is formed as a locking base-side protruding portion 22F3, which protrudes toward the radially outer side of the connecting member-side tube portion 24D of the connecting member 24. As shown in FIGS. Fig. 2 and Fig. 3, the locking base-side protrusion portion 22F is arranged between two of the connecting element-side engagement teeth 24H, and an end portion on the radially inner side of the locking base-side protrusion portion 22F3 is arranged close to portions on the radially inner sides of the two connecting element-side engagement teeth 24H. Thus, as shown in Fig. 4, the lock base side protrusion portion 22F3 and the link side engagement teeth 24H in the circumferential direction (they are arranged one above the other in the circumferential direction).

[0034] As this is Fig. 3, a dimension W1 of the locking base-side protrusion portion 22F3 to the other axial direction side decreases from an end 22D1 on the other axial direction side of the locking base-side tube portion 22D continuously to the outside viewed in the radial direction. Therefore, as shown in Fig. 4, a dimension W2 in the axial direction of the region of overlap in the circumferential direction between the lock base-side engaging tooth 22F and the link-side engaging teeth 22H gradually decreases toward the radially outer side. Thus, an area of ​​the region of overlap between the lock base-side engaging tooth 22F and the link-side engaging teeth 24H in the circumferential direction (areas corresponding to units of distance in the radial direction) gradually decreases toward the radially outer side.

[0035] As mentioned above, the lock base side engaging teeth 22F and the link side engaging teeth 24H are formed to be symmetrical about the biparting line L1 (see FIG. Fig. 1). Accordingly, the structure of each link-side engagement tooth 24H is not described. The locking base-side protrusion portions 22F3 of the locking base-side engagement teeth 22F correspond to the link-side protrusion portions 24H3 of the link-side engagement teeth 24H. Each link-side protrusion portion 24H3 is disposed between two of the locking base-side engagement teeth 22F, and an end portion on the radially inner side of the link-side protrusion portion 24H3 is disposed close to portions on the radially inner sides of the two locking base-side engagement teeth 22F. Thus, as shown in Fig. 4, the connecting member-side protrusion portions 24H3 and the lock base-side engaging teeth 22F in the circumferential direction. Operation of the present embodiment

[0036] The operation of the present embodiment is described below.

[0037] According to the belt winding device 10 of the present embodiment of Fig. 1, when the locking claw 28 engages with the locking teeth of the locking hole 30B during a collision of the vehicle, which is a mode of a time of a vehicle emergency, the rotation of the locking base 22 in the pull-out direction (the direction opposite to the arrow C) is limited (restricted).

[0038] Then, when the micro gas generator (not shown in the drawings) is activated (actuated) during the collision of the vehicle, high-pressure gas generated by the micro gas generator is immediately supplied into the tube in which the carrier 38 is arranged. The carrier 38 is moved by the pressure of this gas and moves over the outer peripheral surface of the locking base-side tube portion 22D of the locking base 22 and the outer peripheral surface of the connecting member-side tube portion 24D of the connecting member 24.

[0039] When the carrier 38 passes over the outer peripheral surface of the locking base-side tubular portion 22D of the locking base 22 and the outer peripheral surface of the link-side tubular portion 24D of the link 24, the locking base-side engaging teeth 22F of the locking base 22 and the link-side engaging teeth 24H of the link 24 bite into the carrier 38, deforming portions of the carrier 38. Thus, kinetic energy of the carrier 38 can be transferred to the locking base 22 and the link 24.

[0040] When the carrier 38 is in the state where the lock base side engagement teeth 22F of the lock base 22 and the link side engagement teeth 24H of the link 24 are bit into the carrier 38, the link 24 and the lock base 22 rotate in the winding direction (the direction of arrow C) together with the spool 14. Consequently, the webbing 16 is wound onto the winding portion 14B of the spool 14, and a restraining force on the vehicle occupant from the webbing 16 is increased.

[0041] In the state where the rotation of the lock base 22 in the pull-out direction is limited, when the vehicle occupant's body pulls the webbing 16 and a rotational force on the spool 14 in the pull-out direction caused by this tensile force is greater than a torsional resistance load (a deformation resistance load) of the torsion shaft 26, the torsion shaft 26 deforms (twists). Therefore, rotation of the spool 14 in the pull-out direction is tolerated by the twisting of the torsion shaft 26, and pull-out of the webbing 16 from the spool 14 is tolerated. Thus, energy (kinetic energy of the vehicle occupant) corresponding to the amount of pull-out of the webbing 16 from the spool 14 is absorbed by the deformation of the torsion shaft 26.

[0042] In the present embodiment, as shown in Fig. 4, the locking base-side protrusion portion 22F3 of each locking base-side engagement tooth 22F with which the carrier 38 engages engages with the link-side engagement teeth 24H in the circumferential direction, and the link-side protrusion portion 24H3 of each link-side engagement tooth 24H with which the carrier 38 engages overlaps with the locking base-side engagement teeth 22F in the circumferential direction. Therefore, each locking base-side engagement tooth 22F deformed by engagement with the carrier 38 can be supported by the link-side engagement teeth 24H, and each link-side engagement tooth 24H deformed by engagement with the carrier 38 can be supported by the locking base-side engagement teeth 22F.As a result, the strength of the engagement teeth with which the carrier 38 engages (the lock base side engagement teeth 22F and the link side engagement teeth 24H) can be ensured.

[0043] The loads applied to the locking base-side engagement teeth 22F are supported (absorbed) by the link-side engagement teeth 24H, and the loads applied to the link-side engagement teeth 24H are supported (absorbed) by the locking base-side engagement teeth 22F. Therefore, the thicknesses (the dimensions in the circumferential direction) of the locking base-side engagement teeth 22F and the link-side engagement teeth 24H can be reduced. Consequently, the biting volumes into the carrier 38 by the locking base-side engagement teeth 22F can be reduced, and the biting volumes into the carrier 38 by the link-side engagement teeth 24H can be reduced.Therefore, the resistance when the carrier 38 engages with the locking base-side engagement teeth 22F and the link-side engagement teeth 24H can be reduced, and the kinetic energy of the carrier 38 can be efficiently transmitted to the link 24 and the locking base 22. Thus, a reduction in the rotating force of the spool 14 when the webbing 16 is wound onto the winding portion 14B of the spool 14 can be suppressed (avoided). Accordingly, the output of the micro gas generator can be reduced, and the wall of the tube into which the gas from the micro gas generator is supplied can be made thinner. Consequently, the size of the webbing winding device 10 can be reduced, and the cost can be reduced.

[0044] With a structure in which the locking base-side engaging teeth 22F and the link-side engaging teeth 24H, which are specified with reduced thicknesses as described above, are alternately arranged in the circumferential direction, the number of engaging teeth (the locking base-side engaging teeth 22F and the link-side engaging teeth 24H) with which the carrier 38 engages can be increased. Consequently, when the carrier 38 engages the engaging teeth, the base 22 and the link 24 can be rotated instantly, and fluctuations in rotational speed amplitude (fluctuations in torque) of the locking base 22 and the link 24 can be reduced.

[0045] In the present embodiment, the area of ​​the overlap portion in the circumferential direction between each lock base-side engagement tooth 22F and link-side engagement tooth 24H gradually decreases toward the radially outer side. Therefore, the resistance can be reduced when the carrier 38 engages the portions on the tooth tip sides (tooth tip sides) (i.e., the radially outer sides) of the lock base-side engagement teeth 22F and the link-side engagement teeth 24H.

[0046] In the present embodiment, an example is described in which the strength of the locking base-side engagement teeth 22F of the locking base 22 and the link-side engagement teeth 24H of the link 24 is ensured by portions of the locking base-side engagement teeth 22F and portions of the link-side engagement teeth 24H that overlap in the circumferential direction. However, the present invention is not limited to this. For example, the strength of first engagement teeth 40A of a first rotor 40 included in the Fig. 5A and Fig. 5B, and second engagement teeth 42A of a second rotor 42, which is shown in the Fig. 6A and Fig. 6B, with which the carrier 38 engages, can be ensured by overlapping portions of the first engagement teeth 40A and portions of the second engagement teeth 42A in the circumferential direction.

[0047] More precisely, how this is done in the Fig. 5A and Fig. 5B, a circular penetrating hole 40B is formed at a circumferentially central portion of a region on the radially inner side of each first engagement tooth 40A of the first rotor 40. Similarly, as shown in the Fig. 6A and Fig. 6B, a projecting portion 42B projecting to an axial direction side is formed at a portion on the radially inner side of each second engagement tooth 42A of the second rotor 42. As shown in the Fig. 7A and Fig. 7B, in a state where two second rotors 42 are arranged on both sides (both sides in the axial direction) of the first rotor 40, the protruding portions 42B of the two second rotors 42 are press-fitted (for example) into the penetrating holes 40B of the first rotor 40. Thus, the first rotor 40 and the second rotors 42 are integrally formed in a state where inner peripheral surfaces of the penetrating holes 40B, which are portions of the first engaging teeth 40A, and outer peripheral surfaces of the protruding portions 42B, which are portions of the second engaging teeth 42A, overlap in the circumferential direction.

[0048] Alternatively, the strength of the first engagement teeth 40A of the first rotor 40 arranged in the Fig. 8A and Fig. 8B, and the second engagement teeth 42A of the second rotor 42 shown in the Fig. 9A and Fig. 9B, with which the carrier 38 engages, can be ensured by overlapping portions of the first engagement teeth 40A and portions of the second engagement teeth 42A in the circumferential direction. As shown in the Fig. 8A and Fig. 8B, each first engagement tooth 40A of the first rotor 40 is provided with a first rotor-side projecting portion 40C extending between two of the second teeth 42A of the second rotor 42, as shown in the Fig. 9A and Fig. 9B. A portion on the radially inner side of the first rotor-side protruding portion 40C is formed in a shape corresponding to (seated in) a portion on the tooth base side (radially inner side) of the second engagement teeth 42A of the second rotor 42. As shown in FIGS. Fig. 10A and Fig.10B, in a state where the first rotor 40 and the second rotor 42 are integrally formed, portions on the radially inner sides of the first rotor-side protruding portions 40C, which are portions of the first engagement teeth 40A, overlap in the circumferential direction with portions on the radially inner sides of the second engagement teeth 42A.

[0049] An embodiment of the present invention has been described above. However, the present invention is not limited to the above description, and it is obvious that various modifications beyond the scope of the present invention can be made within the technical scope that does not deviate from the scope of the present invention.

[0050] Reference is made here to the disclosure of Japanese patent application JP 2016-115596 in its entirety.

[0051] All sources of supply, patent applications and technical standards listed in this description are deemed to be incorporated into this description to the same extent as if the individual sources of supply, patent applications and technical standards were specifically and individually included.

Claims

[1] Belt winding device (10) with: a spool (14) on which a belt (16) to be applied to a vehicle occupant is wound up due to rotation of the spool (14) in a winding direction; a first rotor (22, 40) rotatable together with the spool (14), the first rotor (22, 40) having a first engagement tooth (22F, 40A) with which a moving moving element (38) engages, the first rotor (22, 40) being rotated as a result of the moving moving element (38) engaging the first engagement tooth (22F, 40A); and a second rotor (24, 42) rotatable together with the spool (14), the second rotor (24, 42) having a second engagement tooth (24H, 42A) with which the moving member (38) engages, the second engagement tooth (24H, 42A) being arranged to overlap with the first engagement tooth (22F, 40A) in a rotational circumferential direction of the first rotor (22, 40), and the second rotor (24, 42) being rotated as a result of the moving member (38) engaging the second engagement tooth (24H, 42A). [2] The belt retractor (10) according to claim 1, wherein a plurality of the first engagement teeth (22F, 40A) and a plurality of the second engagement teeth (24H, 42A) are alternately arrayed in the rotational circumferential direction of the first rotor (22, 40) and the second rotor (24, 42). [3] The belt retractor (10) according to claim 1 or 2, wherein the first engagement tooth (22F, 40A) and the second engagement tooth (24H, 42A) are configured such that an overlap area between the first engagement tooth (22F, 40A) and the second engagement tooth (24H, 42A) in the rotational circumferential direction of the first rotor (22, 40) and the second rotor (24, 42) becomes smaller toward a rotational radial direction outside of the first rotor (22, 40) and the second rotor (24, 42).

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