Seat belt retractor

Abstract

A seat belt reeling device is provided to suppress the increase of a temporary force-limiting load. The seat belt reeling device (10) comprises: a reel (20) capable of pulling out a seat belt (20A) and reeling in the seat belt (20A); a rotating body (50) arranged to face the reel (20) and prevented from rotating in an emergency. The seat belt reeling device (10) comprises: a wire (40) whose base end (42) is retained, the wire (40) being arranged between the rotating body (50) and the reel (20) and being wound around an inner rib (26) of the reel (20) when deformed and the seat belt (20A) is pulled out in an emergency; and a retracting portion (24B) for allowing the end portion (48) of the wire (40) to retract when the wire (40) is wound around the inner rib (26).

Description

Technical Field

[0001] The invention relates to a safety belt reeling device. Background Art

[0002] Seatbelt retractors are known that include a force limiter mechanism to prevent an increase in the load applied to the seatbelt and compression of the chest. When a load exceeding a certain value is applied to the seatbelt, the force limiter mechanism reduces the load (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses a technology in which an energy absorbing pin is embedded in an axial hole of a reel. In an emergency, the torsion bar is twisted and the energy absorbing pin is pulled out from the reel to absorb energy.

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2007-331563

[0005] Here, it is preferable to suppress a temporary increase in the force-limiting load in such a seatbelt retractor. Summary of the Invention

[0006] The present invention has been made in consideration of the above-mentioned situation, and an object of the present invention is to provide a seatbelt retractor capable of suppressing a temporary increase in a force-limiting load.

[0007] The first embodiment of the seat belt reeling device of the present invention comprises: a reel that can pull out the seat belt and reel in the seat belt; a rotating body that is arranged to face the above-mentioned reel and is prevented from rotating in an emergency; a wire whose base end is retained, the wire being arranged between the above-mentioned rotating body and the above-mentioned reel, and being wound around the winding portion of the above-mentioned reel when the wire is deformed and the seat belt is pulled out in an emergency; and a retraction portion that allows the terminal end of the wire to retract when the wire is wound around the above-mentioned winding portion.

[0008] A seatbelt retractor according to a second aspect of the present invention is the seatbelt retractor according to the first aspect of the present invention, wherein the retraction portion is formed in a sloped shape on the winding portion.

[0009] A seatbelt retractor according to a third aspect of the present invention is the seatbelt retractor according to the first or second aspect of the present invention, wherein the escape portion is formed in a concave shape around the winding portion.

[0010] A seatbelt retractor according to a fourth aspect of the present invention is the seatbelt retractor according to any one of the first to third aspects of the present invention, wherein the retraction portion is formed recessed inward in the retraction direction on the side of the retraction portion.

[0011] With respect to the fifth aspect of the seatbelt retracting device of the present invention, in any one of the first to fourth aspects of the present invention, the retraction portion is formed around the receiving hole of the reel, and the receiving hole of the reel receives the terminal portion of the wire.

[0012] A seatbelt retractor according to a sixth aspect of the present invention is the seatbelt retractor according to any one of the first to fifth aspects of the present invention, wherein a plurality of the wire members are provided.

[0013] The seatbelt retractor according to the first aspect of the present invention includes a retracting portion. When the wire is wound around the reeling portion, the retracting portion allows the distal end of the wire to retract, thereby preventing the distal end of the wire from scraping the reeling portion. This prevents a temporary increase in the load acting on the reel from the wire during winding. Consequently, a temporary increase in the load-limiting load can be suppressed.

[0014] In the second embodiment of the seatbelt retractor of the present invention, the retreat portion is formed in a sloped shape on the winding portion, so that when the wire is wound on the winding portion, the end portion of the wire is guided (introduced) to the retreat portion formed in the slope. Therefore, the end portion of the wire is prevented from being strongly pressed by the winding portion. As a result, the situation in which the end portion of the wire scrapes the winding portion is suppressed. Therefore, a simple structure can suppress a temporary increase in the force-limiting load.

[0015] In the seatbelt retractor of the third embodiment of the present invention, the retracting portion is formed concavely around the winding portion. As a result, when the wire is wound around the winding portion, the terminal end of the wire retreats into the concave retracting portion. This prevents the terminal end of the wire from being strongly pressed by the winding portion. As a result, it is possible to prevent the terminal end of the wire from scraping the winding portion. Thus, a simple structure can suppress a temporary increase in the force-limiting load.

[0016] In the seatbelt retractor according to the fourth aspect of the present invention, the winding portion is recessed inwardly in the winding direction on the side of the retracting portion, thereby creating a space inwardly in the winding direction for the distal end of the wire to retract. This further reduces the possibility of the distal end of the wire scraping the winding portion. Consequently, a temporary increase in the load acting on the reel from the wire during winding is further reduced. Consequently, a temporary increase in the load-limiting load can be further reduced.

[0017] In the fifth aspect of the seatbelt retractor of the present invention, a retraction portion is formed around the receiving hole of the reel. When the end of the wire is pulled out of the receiving hole, the end of the wire retreats into the retraction portion. This prevents the end of the wire from scraping the winding portion when it is pulled out of the receiving hole. Consequently, a temporary increase in the force-limiting load can be suppressed.

[0018] In the seatbelt retractor of the sixth aspect of the present invention, a plurality of wires are provided. Therefore, even if the movement of the terminal end of the wire toward the radially outer side of the spool is blocked by other wires, the escape portion can suppress the terminal end from scraping the winding portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is an exploded perspective view showing the seatbelt retractor according to the first embodiment.

[0020] Figure 2 It is a perspective view showing the spool and the pinion gear according to the first embodiment.

[0021] Figure 3 is a cross-sectional view showing a seat belt retractor according to a first embodiment. Figure 2 AA section.

[0022] Figure 4 This is an exploded perspective view showing a state before a wire rod is inserted into the receiving hole formed in the reel according to the first embodiment.

[0023] Figure 5 is a cross-sectional view showing one end side of the seatbelt retractor according to the first embodiment. Figure 5 (A) indicates a scroll, Figure 5 (B) represents the reel, wire and pinion.

[0024] Figure 6 This is a side view showing the reel according to the first embodiment as viewed from one end side.

[0025] Figure 7 This is a side view showing the reel according to the first embodiment as viewed from one end side. Figure 7 (A) indicates that the seat belt is pulled out and the reel is rotating in the pulling direction. Figure 7 (B) shows a state where the seat belt is further pulled out and the spool is further rotated in the pulling direction.

[0026] Figure 8 This is a side view showing the reel according to the second embodiment as viewed from one end side.

[0027] Figure 9 1 is a diagram showing a reel according to a second embodiment. Figure 9 (A) is a side view showing a state where the seat belt is pulled out and the spool is rotated in the pulling-out direction, as viewed from one end of the spool. Figure 9 (B) means Figure 9 (A) is a cross-sectional view of the BB section.

[0028] Description of Reference Numerals

[0029] 10...seatbelt retractor; 20A...seatbelt; 20...spool; 50...rotating body; 42...base end portion; 26...inner rib (an example of a winding portion); 24B...retracting portion; 29...accommodating hole. DETAILED DESCRIPTION

[0030] [First embodiment]

[0031] The following describes a seatbelt retractor according to a first embodiment with reference to the accompanying drawings. In each figure, arrow FR indicates the front in the vehicle's longitudinal direction, arrow OUT indicates the outside in the vehicle's width direction, and arrow UP indicates the upper direction in the vehicle's vertical direction. In each figure, arrow A indicates the direction of rotation of the reel 20 when reeling the seatbelt 20A, i.e., the reeling direction A, and arrow B indicates the withdrawal direction B opposite to the reeling direction A. In each figure, the axial direction of the reel 20 is referred to as the axial direction D. When only one end and the other end are used in the description, unless otherwise specified, this refers to the axial direction D of the reel 20.

[0032] [Structure of the seat belt retractor]

[0033] like Figure 1 As shown, the seatbelt retractor 10 mainly includes a frame 12 , a cover 14 , a biasing mechanism 16 , a sensor mechanism 18 , a spool 20 , a shaft 30 , a rotating body 50 , and a cylinder 60 .

[0034] (Frame 12)

[0035] The frame 12 is made of metal and is fixed to the lower side of the vehicle, which serves as the center pillar of the vehicle body (not shown). When viewed from the top and bottom of the vehicle, the frame 12 is formed in the shape of a square tube and has a leg plate 12A formed on the front side of the vehicle and a leg plate 12B formed on the rear side of the vehicle. A circular through-hole 12C is formed in the leg plate 12A, extending in the front-to-rear direction of the vehicle. A circular through-hole 12D is formed in the leg plate 12B, extending in the front-to-rear direction of the vehicle. The reel 20, which is inserted into the through-hole 12C of the leg plate 12A and the through-hole 12D of the leg plate 12B, is supported by the leg plate 12A and the leg plate 12B so as to be rotatable.

[0036] (Scroll 20)

[0037] The spool 20 is formed in a generally cylindrical shape and is rotatable about a central axis C in a reeling direction A and a withdrawing direction B. The longitudinal base end of a long, strip-shaped seatbelt 20A is secured to the spool 20. Rotating the spool 20 in the reeling direction A winds the seatbelt 20A onto the spool 20. By withdrawing the seatbelt 20A from the spool 20, the seatbelt 20A rotates in the withdrawing direction B. Furthermore, by withdrawing the seatbelt 20A from the spool 20, the seatbelt 20A is worn by a passenger seated in a vehicle seat.

[0038] (Force applying mechanism 16)

[0039] A biasing mechanism 16 is provided on the vehicle rear side of the frame 12. The biasing mechanism 16 includes a reel biasing unit (not shown) such as a coil spring. The reel biasing unit directly or indirectly engages with the reel 20 and biases the reel 20 in the winding direction A.

[0040] (Shaft 30)

[0041] like Figure 3 As shown, the shaft body 30 is composed of a torsion shaft 32 as a first energy absorbing member and a sub-shaft body 34 .

[0042] The torsion shaft 32 is made of metal and has a generally cylindrical shape. It is located within the spool 20 and coaxially with the central axis C of the spool 20. The other end of the torsion shaft 32 (on the rear side of the vehicle) is rotatably coupled to the spool 20. The other end of the torsion shaft 32 is rotatably supported by the biasing mechanism 16.

[0043] One end of the torsion shaft 32 (on the vehicle front side) is coaxially connected to a sub-shaft 34. The sub-shaft 34 is made of metal and has a generally cylindrical shape. One end of the sub-shaft 34 is rotatably supported by the sensor mechanism 18. The torsion shaft 32 constitutes a first force limiting mechanism, which serves as a force limiting mechanism.

[0044] (rotating body 50)

[0045] like Figure 1 and Figure 3 As shown, the rotating body 50 constituting the locking mechanism is disposed so as to face the spool 20 in the axial direction D. The rotating body 50 is composed of a pinion 52 and a locking base 54. The locking base 54 is disposed closer to the front of the vehicle than the pinion 52. The locking base 54 is formed into a circular plate shape, for example, by aluminum die-casting, and is coaxial with the central axis C of the spool 20.

[0046] like Figure 2 and Figure 3As shown, the pinion gear 52 is formed in a disk shape by, for example, aluminum die casting, and is disposed coaxially with the central axis C of the spool 20. The pinion gear 52 is coupled to a lock base 54 so as to be rotatable as a unit.

[0047] The torsion shaft 32 is fitted onto one end of the pinion 52, restricting relative rotation between the pinion 52 and the torsion shaft 32. This allows the spool 20, torsion shaft 32, lock base 54, and pinion 52 to rotate integrally.

[0048] like Figure 1 As shown, the lock base 54 includes a lock claw 56. The lock claw 56 is rotatably supported by the lock base 54.

[0049] like Figure 2 As shown, the pinion gear 52 is formed with two through holes 52A that penetrate in the axial direction D. The through holes 52A can be elongated holes.

[0050] (Cover 14)

[0051] like Figure 1 and Figure 3 As shown, a metal cover 14 covering the pinion 52 and the lock base 54 is fixed to the leg plate 12A on the vehicle front side of the frame 12. The cover 14 has ratchet teeth 14A formed in a ratchet hole extending through the cover 14 in the vehicle front-rear direction.

[0052] (Sensor mechanism 18)

[0053] A sensor mechanism 18 is provided on the vehicle front side of the cover 14. In an emergency, the sensor mechanism 18 activates, causing the locking pawl 56 to rotate and move radially outward from the locking base 54. The distal end of the locking pawl 56 engages with the ratchet teeth 14A. This restricts rotation of the locking base 54 in the extension direction B, indirectly restricting rotation of the spool 20 in the extension direction B. Emergency situations include sudden vehicle deceleration, such as during a collision, or sudden withdrawal of the seatbelt 20A from the spool 20.

[0054] (Cylinder 60)

[0055] like Figure 1 As shown, the seatbelt retractor 10 includes a cylinder 60 that serves as a pretensioner. A micro gas generator 62 (hereinafter referred to as MGG 62) is inserted into the base end of the cylinder 60. The MGG 62 is electrically connected to a collision detection sensor (not shown) installed in the vehicle via an ECU (not shown). A sealing ball 64, serving as a piston, and a moving member 66 are located inside the cylinder 60.

[0056] When the collision detection sensor detects an impact during a vehicle collision, the MGG 62 generates gas, and the movable member 66 is pressed by the sealing ball 64, moving toward the distal end of the cylinder 60. Furthermore, the movable member 66 moves while the teeth of the pinion 52 and the lock base 54 are meshed (engaged or engaged), causing the spool 20 to rotate in the reeling direction A, reeling the seat belt 20A and securing the occupant to the vehicle seat.

[0057] [Structure of the second force limiting mechanism]

[0058] like Figure 3 As shown, two wires 40 serving as second energy absorbing members are provided on the reel 20 . The second energy absorbing members constitute a second force limiting mechanism serving as a force limiting mechanism.

[0059] (Wire 40)

[0060] The wire 40 is formed of a metal (such as piano wire) having a higher strength than the reel 20. The wire 40 is formed of a metal that is less susceptible to scraping than the reel 20. The two wires 40 can have the same length and shape.

[0061] like Figure 4 As shown, the wire 40 is formed in a substantially crank shape by a base end portion 42 , a first intermediate portion 44 , a second intermediate portion 45 , a third intermediate portion 46 , and a terminal portion 48 .

[0062] The base end portion 42 is formed in a disk shape. The outer diameter of the base end portion 42 is formed to be larger than at least the minimum inner diameter of the through hole 52A formed in the pinion gear 52 .

[0063] The first intermediate portion 44 is formed in a round rod shape extending from the base end portion 42 toward the other end. The second intermediate portion 45 is formed in a round rod shape extending from the other end of the first intermediate portion 44 in a direction substantially perpendicular to the axial direction D. The third intermediate portion 46 is formed in a round rod shape extending from the end of the second intermediate portion 45 along the axial direction D. The first intermediate portion 44, the second intermediate portion 45, and the third intermediate portion 46 can have substantially the same diameter.

[0064] The terminal portion 48 is formed in a truncated cone shape that decreases in diameter from the other end of the third intermediate portion 46 in the axial direction D. The terminal portion 48 is formed in a shape that tapers toward the terminal end of the wire 40 .

[0065] (Scroll 20)

[0066] like Figure 4 As shown, the spool 20 includes a substantially cylindrical spool body 21 and a flange 22 formed on one end side in the axial direction D of the spool body 21 .

[0067] The flange portion 22 is formed in a disk shape having a larger outer shape than the reel body portion 21 , and includes an outer rib 23 , an inner rib 26 constituting a winding portion, and a groove portion 28 .

[0068] The outer rib 23 is formed on the outer edge of the flange portion 22 so as to protrude toward one end in the axial direction D. The outer rib 23 is formed in an annular shape. The inner rib 26 is formed on the inner edge of the flange portion 22 so as to protrude toward one end in the axial direction D. The inner rib 26 is formed in an annular shape. The groove 28 is formed between the outer rib 23 and the inner rib 26 as an annular groove that is recessed toward the other end in the axial direction D. The groove 28 accommodates the second intermediate portion 45 of the wire rod 40.

[0069] like Figure 3 and Figure 6 As shown, two receiving holes 29 are formed in the groove portion 28 to receive the third intermediate portion 46 and the terminal portion 48 of the wire 40. The two receiving holes 29 are provided approximately point-symmetrically with respect to the central axis C of the reel 20 in a cross section perpendicular to the central axis C of the reel 20. In other words, the two wires 40 are provided approximately point-symmetrically with respect to the central axis C in a cross section perpendicular to the central axis C of the reel 20.

[0070] like Figure 3 As shown, the housing hole 29 can be a circular through-hole that penetrates the spool 20 in the axial direction D. The inner diameter of the housing hole 29 is formed to be slightly larger than the outer diameter of the third intermediate portion 46 of the wire rod.

[0071] like Figure 6 As shown, the receiving hole 29 is formed in the radially inner portion of the groove 28. At least part of the receiving hole 29 is formed in the portion where the inner rib 26 is formed in the radial direction of the spool 20. The receiving hole may also be a blind hole (non-through hole).

[0072] like Figure 4 and Figure 6 As shown, the inner rib 26 is formed by an inner portion 25 and an outer portion 24 .

[0073] The inner portion 25 is formed in a substantially annular shape and has a substantially uniform thickness in the radial direction.

[0074] Two outer portions 24 are formed on the outside of the inner portion 25, connecting the two receiving holes 29. The outer portion 24 includes a main portion 24A and a recessed portion 24B. The main portion 24A extends from the two receiving holes 29 at a predetermined angle (e.g., 120 degrees) in the pull-out direction B. The height of the main portion 24A in the axial direction D can be substantially constant.

[0075] The escape portions 24B are formed to extend from the ends of the main body 24A in the pull-out direction B at a predetermined angle (e.g., 30 degrees) in the pull-out direction B. The escape portions 24B are formed near the receiving hole 29 of the reel 20 that receives the terminal portion 48 of the wire 40. The radial width of the escape portion 24B is formed to narrow as it approaches the receiving hole 29. In other words, the inner rib 26 constituting the winding portion is formed to be recessed inwardly in the winding direction (the circumferential direction of the inner rib 26) on the side of the escape portion 24B.

[0076] like Figure 5 As shown in (A) of FIG, the escape portion 24B is formed to be inclined from the end surface of the main body portion 24A on the one end side in the axial direction D toward the bottom surface of the groove portion 28. In other words, the end surface of the escape portion 24B on the one end side in the axial direction D is formed in a slope shape that is inclined from the end surface of the main body portion 24A on the one end side in the axial direction D toward the bottom surface of the groove portion 28.

[0077] The length of the sloped escape portion 24B can be substantially the same as that of the terminal portion 48. The length of the sloped escape portion 24B can be longer or shorter than that of the terminal portion 48.

[0078] The end surface of the escape portion 24B on one end side in the axial direction D is formed at a predetermined angle θ1 (for example, 15°) relative to a vertical plane perpendicular to the axial direction D. As will be described later, when the terminal end 48 of the wire 40 is released from the receiving hole 29, Figure 5 As shown in (B), the line L1 connecting the contact point P1 where the distal end 48 of the wire 40 contacts the groove 28 around the receiving hole 29 and the contact point P2 where the distal end 48 of the wire 40 contacts the pinion 52 is formed at an angle θ2 (e.g., 15°) that is the same as the angle θ1 with respect to a vertical plane perpendicular to the axial direction D. The angle θ1 and the angle θ2 may also be different angles.

[0079] like Figure 2 and Figure 3 As shown, the first intermediate portion 44, the second intermediate portion 45, the third intermediate portion 46, and the distal end portion 48 are inserted into the through-hole 52A formed in the pinion 52, and the base end portion 42 is retained by the pinion 52. The third intermediate portion 46 and the distal end portion 48 are inserted into the receiving hole 29. The second intermediate portion 45 is received in the groove 28. That is, the second intermediate portion 45 is disposed between the pinion 52 and the spool 20.

[0080] [Action of the force limiting mechanism]

[0081] In the seatbelt retractor 10, the seatbelt 20A is pulled from the spool 20 and is then worn by the occupant. Furthermore, the spool 20 is rotated in the reeling direction A by the biasing force of the coil spring of the biasing mechanism 16, and the seatbelt 20A is reeled onto the spool 20, thereby removing slack from the seatbelt 20A worn by the occupant.

[0082] When the vehicle collides, the sensor mechanism 18 operates, and the locking pawl 56 rotates in a direction approaching the ratchet teeth 14A of the cover plate 14, causing the locking pawl 56 to engage with the ratchet teeth 14A, thereby restricting the rotation of the lock base 54 in the pulling direction B and restricting the rotation of the spool 20 in the pulling direction B.

[0083] Thus, the rotation of the spool 20 in the withdrawal direction B is restricted, thereby restricting withdrawal of the seat belt 20A wound around the spool 20. Therefore, the body of the occupant who is inertially moving toward the front of the vehicle when the vehicle suddenly decelerates is restrained by the seat belt 20A.

[0084] In this state, if the body of the passenger who wants to move inertially toward the front side of the vehicle pulls the seat belt 20A, and if the torque applied to the reel 20 in the pulling direction B is higher than the mechanical strength of the torsion shaft 32 and the wire 40, the torsion shaft 32 twists and begins to plastically deform, and the reel 20 begins to rotate in the pulling direction B relative to the locking base 54 whose rotation is restricted.

[0085] Furthermore, if the reel 20 starts to rotate in the pulling direction B relative to the locking base 54, Figure 7 As shown in FIG. 2A , the third intermediate portion 46 of the wire 40 is released from the accommodating hole 29 while the base end portion 42 is held by the pinion 52 .

[0086] Thus, the third intermediate portion 46 that has escaped from the receiving hole 29 is held by the opening edge 29A of the receiving hole 29 (see Figure 4 ) and is pressed against the outer peripheral wall of the outer portion 24, being bent along the outer peripheral wall, and the second intermediate portion 45 and the third intermediate portion 46 of the wire 40 are wound around the outer portion 24. That is, when the wire 40 is deformed in an emergency and the seat belt 20A is pulled out, it is wound around the outer portion 24 of the spool 20.

[0087] Here, when the pullout load applied by the occupant to pull the seat belt 20A from the spool 20 (the rotational load on the spool 20 in the pullout direction B) is greater than the sum of the torsional load (first load-limiting load) of the torsion shaft 32 and the deformation load (second load-limiting load) of the pair of wires 40, the torsion shaft 32 is torsionally deformed, and the pair of wires 40 are deformed, allowing the spool 20 to rotate relative to the lock base 54 and the pinion 52 in the pullout direction B. As a result, the kinetic energy of the occupant is absorbed by the torsional deformation of the torsion shaft 32 and the deformation of the pair of wires 40, thereby protecting the occupant.

[0088] If the reel 20 is further rotated in the pulling direction B relative to the locking base 54, Figure 7 As shown in (B), with the base end portion 42 held by the pinion 52, the terminal portion 48 of the wire 40 is released from the receiving hole 29. When the terminal portion 48 of the wire 40 is released from the receiving hole 29 and the second intermediate portion 45 and the third intermediate portion 46 of the wire 40 are wound around the outer portion 24 of the reel 20, the terminal portion 48 of the wire 40 is guided by the end surface of the one end side of the axial direction D of the retreat portion 24B formed in a sloped shape.

[0089] Furthermore, at this time, the wire 40 is intended to rotate about the base end portion 42 held by the pinion 52. Furthermore, the second intermediate portion 45 or the third intermediate portion 46 radially presses the terminal end 48 of the other wire 40. At this time, a space is formed between the terminal end 48 and the inner rib 26, which is formed by the inner rib 26 being recessed inwardly in the winding direction on the side of the retracted portion 24B.

[0090] Here, when the pullout load of the seat belt 20A from the spool 20 (the rotational load of the spool 20 in the pullout direction B) applied by the occupant is greater than the torsional resistance load (first limiter load) of the torsion shaft 32 , the torsion shaft 32 is torsionally deformed.

[0091] Thus, the kinetic energy of the occupant is absorbed by the torsional deformation of the torsion shaft 32 , thereby protecting the occupant.

[0092] That is, the kinetic energy of the occupant is absorbed in two stages, first by the torsional deformation of the torsion shaft 32 and the deformation of the pair of wire members 40 , and then by the torsional deformation of the torsion shaft 32 , thereby protecting the occupant.

[0093] [Function of the First Embodiment]

[0094] Next, the operation of the first embodiment will be described.

[0095] The seatbelt retractor 10 of the first embodiment includes a spool 20 capable of retracting and retracting a seatbelt 20A, and a rotating body 50 disposed opposite the spool 20 and prevented from rotating in an emergency. The seatbelt retractor 10 includes a wire 40 having a base end 42 held therein. The wire 40 is disposed between the rotating body 50 and the spool 20 and is wound around the inner rib 26 of the spool 20 when deformed and the seatbelt 20A is retracted in an emergency. A retractor 24B allows a terminal end 48 of the wire 40 to be retracted when the wire 40 is wound around the inner rib 26.

[0096] However, if the inner rib 26 lacks the escape portion 24B, when the terminal end 48 of the wire 40 is pulled out of the receiving hole 29 of the spool 20, the terminal end 48 of the wire 40 is released from its position, causing it to be strongly pressed against the inner rib 26. Furthermore, the base end 42 of the wire 40 is held eccentrically relative to the spool 20. Therefore, when the wire 40 is wound around the inner rib 26, the wire 40 attempts to rotate inward in the winding direction about the base end 42 held by the pinion 52, but the terminal end 48 of the wire 40 cannot escape the inner rib 26. Furthermore, since the terminal end 48 of the wire 40 bends inward in the winding direction as it is pulled, it is also strongly pressed against the inner rib 26. Here, the wire 40 formed of piano wire is less susceptible to scraping than the spool 20 formed of aluminum die casting. Therefore, the terminal end 48 of the wire 40 is strongly pressed against the inner rib 26, and the inner rib 26 of the reel 20 is scraped. As a result, the restraining load caused by the wire 40 temporarily increases.

[0097] In the first embodiment, the escape portion 24B is provided. When the wire 40 is wound around the inner rib 26, the end portion 48 of the wire 40 is allowed to escape from the escape portion 24B, thereby preventing the inner rib 26 from being scraped by the end portion 48 of the wire 40. Therefore, a temporary increase in the load acting on the reel 20 from the wire 40 when the wire 40 is wound is suppressed. As a result, a temporary increase in the limit load generated by the wire 40 can be suppressed.

[0098] In the webbing retractor 10 according to the first embodiment, the escape portion 24B is formed in the inner rib 26 in a sloped shape.

[0099] The relief portion 24B is formed in a sloped shape on the inner rib 26. When the wire 40 is wound around the inner rib 26, the distal end 48 of the wire 40 is guided (or directed) to the sloped relief portion 24B. This prevents the distal end 48 of the wire 40 from being strongly pressed against the inner rib 26. As a result, the distal end 48 of the wire 40 is prevented from scraping the inner rib 26. Thus, a simple structure that does not require large dimensions can suppress a temporary increase in the limiting load generated by the wire 40.

[0100] In the webbing retractor 10 according to the first embodiment, the inner rib 26 is formed so as to be recessed inward in the retraction direction on the side of the escape portion 24B.

[0101] The inner rib 26 is recessed inwardly in the winding direction on the side of the retracted portion 24B, thereby creating a space on the inner side in the winding direction for the terminal end 48 of the wire 40 to retreat. Therefore, even when a force is applied by the outer wire 40 to press the terminal end 48 of the wire 40 radially inwardly of the reel 20, a space is created on the inner side in the winding direction for the terminal end 48 of the wire 40 to retreat. As a result, scraping of the inner rib 26 by the terminal end 48 of the wire 40 is further suppressed. Furthermore, a temporary increase in the load acting on the reel 20 from the wire 40 during winding is further suppressed. As a result, a temporary increase in the force-limiting load generated by the wire 40 can be further suppressed.

[0102] In the webbing retractor 10 according to the first embodiment, the escape portion 24B is formed in the vicinity of the housing hole 29 of the spool 20 in which the terminal end portion 48 of the wire 40 is housed.

[0103] The escape portion 24B is formed near the receiving hole 29 of the reel 20. When the terminal end 48 of the wire 40 is pulled out of the receiving hole 29, the terminal end 48 of the wire 40 escapes into the escape portion 24B. This prevents the terminal end 48 of the wire 40 from scraping the inner rib 26 when the terminal end 48 of the wire 40 is pulled out of the receiving hole 29 of the reel 20. As a result, a temporary increase in the limiting load generated by the wire 40 can be suppressed.

[0104] In the seatbelt retractor 10 according to the first embodiment, two wires 40 are provided.

[0105] By providing two wires 40, even if the movement of the terminal end 48 of the wire 40 toward the radially outer side of the reel 20 is blocked by the other wire 40, the relief portion 24B can prevent the terminal end 48 from scraping the inner rib 26. In addition, the load-limiting load can be applied to the two wires 40, thereby achieving a load-limiting structure that generates a two-stage load-limiting load of a high load.

[0106] Furthermore, by using longer wires 40, the stroke over which the load-limiting load acts can be lengthened. Furthermore, since the width of the main body portion 24A of the inner rib 26 is constant, and the width of the recessed portion 24B is recessed inward in the winding direction, the shape of the winding member 240 can be prevented from becoming elliptical when the two wires 40 are wound. In other words, the shape of the winding member 240 can be maintained circular. Consequently, a temporary increase in the load-limiting load can be suppressed.

[0107] [Second embodiment]

[0108] The seatbelt retractor according to the second embodiment differs from the seatbelt retractor according to the first embodiment in that the structure of the retracting portion is different.

[0109] Hereinafter, the structure of the seatbelt retractor according to the second embodiment will be described. Components identical or equivalent to those described in the first embodiment will be described using the same terms or reference numerals.

[0110] [Structure of the seat belt retractor]

[0111] like Figure 8 As shown, an inner rib 126 constituting the winding portion is formed on the inner edge of the flange portion 22 so as to protrude toward one end in the axial direction D. The inner rib 126 is formed in an annular shape and is composed of an inner portion 25 and an outer portion 124.

[0112] Two outer portions 124 are formed on the outer side of the inner portion 25 so as to connect the two receiving holes 29. The height of the outer portion 124 in the axial direction D can be substantially constant.

[0113] like Figure 8 and Figure 9 As shown in FIG. 1B , the relief portion 128 is formed into a concave shape that is recessed from the bottom surface of the groove portion 28 toward the other end in the axial direction D. The relief portion 128 is provided to extend from the receiving hole 29 in the winding direction A. The relief portion 128 is provided radially outward of the inner portion 25. The relief portion 128 is formed so as to extend from the receiving hole 29 until it reaches the outer side of the wire 40 when the wire 40 is radially overlapped and wound around the inner rib 126, which serves as the winding portion. In other words, the relief portion 128 is formed in a concave shape around the outer portion 124.

[0114] The length of the retraction portion 128 in the retraction direction A can be substantially the same as the length of the terminal portion 48. The axial depth of the retraction portion 128 is formed to be approximately equal to the maximum diameter of the terminal portion 48. The retraction portion 128 is formed to be connected to the receiving hole 29, and an opening edge 29A is formed between the retraction portion 128 and the receiving hole 29.

[0115] [Action of the force limiting mechanism]

[0116] The webbing retractor 110 of the second embodiment operates similarly to the webbing retractor 10 of the first embodiment until the distal end 48 of the wire 40 is released from the accommodating hole 29 while the proximal end 42 is held by the pinion 52 .

[0117] The terminal portion 48 of the wire 40 is released from the receiving hole 29, and the second intermediate portion 45 and the third intermediate portion 46 of the wire 40 are wound around the outer portion 124 of the reel 20. Figure 9 (A) and Figure 9 As shown in FIG. 1B , the terminal portion 48 of the wire rod 40 is guided to the escape portion 128 and penetrates into the other end side in the axial direction D of the second intermediate portion 45 of the other wire rod 40 .

[0118] [Function of the Second Embodiment]

[0119] In the webbing retractor 10 according to the second embodiment, the escape portion 128 is formed in a concave shape along the axial direction D of the spool 20 in the vicinity of the housing hole 29 of the spool 20 .

[0120] The escape portion 128 is formed concavely along the axial direction D of the spool 20 near the receiving hole 29 of the spool 20. This allows the second intermediate portion 45 of the other wire 40 to press against the terminal end 48 of the wire 40 when the wire 40 is wound around the inner rib 126 and the terminal end 48 of the wire 40 escapes from the receiving hole 29. In other words, the terminal end 48 of one wire 40 can be forced under another wire 40. This prevents the terminal end 48 of the wire 40 from being strongly pressed against the inner rib 126. Consequently, the terminal end 48 of the wire 40 is prevented from scraping the inner rib 126. Thus, a simple structure can suppress a temporary increase in the limiting load generated by the wire 40.

[0121] In addition, other structures and effects are substantially the same as those of the first embodiment, and therefore description thereof will be omitted.

[0122] The seatbelt retractor of the present invention has been described above based on the aforementioned embodiments. However, the specific structure is not limited to these embodiments, and design modifications are permitted without departing from the spirit of the invention as set forth in the claims. Furthermore, the retracting portion 24B of the first embodiment can be combined with the retracting portion 128 of the second embodiment.

[0123] In the above-described embodiments, the terminal portion 48 is formed in an example in which the terminal end is tapered toward the terminal end of the wire 40. However, the terminal portion is not limited to this form and may be formed in a round rod shape.

[0124] In the above-mentioned embodiments, the wire 40 is formed into a substantially crank shape. However, the wire is not limited to this form, and may be formed into a straight rod shape, for example.

[0125] In the above embodiments, the housing hole 29 is formed in the radially inner portion of the groove 28. However, the housing hole may be formed in the radially outer portion of the groove 28 or in the radially middle portion.

[0126] In the above embodiments, examples are shown in which the two wires 40 are of the same length and shape. However, the two wires may also be of different lengths. Thus, the passenger's kinetic energy is absorbed in three stages: first by the torsional deformation of the torsion shaft 32 and the deformation of the two wires 40, then by the torsional deformation of the torsion shaft 32 and the deformation of one wire 40, and finally by the torsional deformation of the torsion shaft 32, thereby protecting the passenger. Furthermore, the two wires 40 may also have different diameters.

[0127] In each of the above-described embodiments, an example is shown in which two wires 40 are provided on the reel 20. However, the reel 20 may be provided with one wire 40 or three or more wires 40.

Claims

1. A seat belt reeling device, characterized in that: have: a reel capable of extending and retracting the seat belt; a rotating body, which is arranged to face the reel and is prevented from rotating in an emergency; a wire having a base end portion held, the wire being disposed between the rotating body and the reel and being wound around a winding portion of the reel when the wire is deformed and the seat belt is pulled out in an emergency; and a retreat portion for retreating the end portion of the wire when the wire is wound on the winding portion; The retreat portion is formed near the receiving hole of the reel in which the terminal end of the wire is received. In the radial direction of the reel, the width of the retreat portion is formed to become narrower as it approaches the receiving hole. In the axial direction of the winding shaft, the end surface of the retreat portion on one end side is formed in a slope shape that is inclined toward the other end side.

2. The seat belt retracting device according to claim 1, characterized in that: The retreat portion is formed in a slope shape on the winding portion.

3. The seat belt retracting device according to claim 1 or 2, characterized in that: The escape portion is formed in a concave shape around the winding portion.

4. The seat belt retracting device according to claim 1 or 2, characterized in that: The winding portion is formed to be recessed inwardly in the winding direction on the side of the retreat portion.

5. The seat belt retracting device according to claim 1 or 2, characterized in that: The escape portion is formed around the receiving hole of the reel.

6. The seat belt retracting device according to claim 1 or 2, characterized in that: A plurality of the wires are provided.

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