Retractor for seat belt

Abstract

The invention provides a retractor for a seat belt, which can stabilize the pulling force of a pretensioner on a webbing. A retractor for a seat belt is provided with a take-up drum (3), a lock base (6), and a pre-tensioner (1C). The pretensioner (1C) comprises a drive wheel (5), a pressure vessel (12) and a moving member (13). The pressure vessel (12) is provided in such a manner that the opening direction of the tip section (12a) is inclined with respect to the winding drum (3) side or the opposite side of the winding drum (3), said surface being orthogonal to the axial direction of the winding drum (3). When the pretensioner (1C) is operated, the moving member (13) moves the lock base (6), the drive wheel (5), and the take-up drum (3) in the axial direction of the take-up drum (3) toward the opening direction side of the tip (12a) of the pressure vessel (12), thereby bringing any one of the lock base (6), the drive wheel (5), and the take-up drum (3) into contact with the restricting member.

Description

TECHNICAL FIELD

[0001] The present application relates to a seat belt retractor including a pretensioner for removing slack of a webbing at the time of emergency such as a vehicle collision. BACKGROUND

[0002] Conventionally, a seat belt retractor including a pretensioner for removing slack of a webbing at the time of emergency such as a vehicle collision is known. For example, in Japanese Patent No. 6752631, a seat belt retractor 100 as shown in FIG. 1 is disclosed. Figure 20

[0003] Specifically, in the seat belt retractor 100, a winding drum 120 (referred to as a "winding drum" in Japanese Patent No. 6752631) that winds a webbing 200 is housed between a pair of side walls 111, 112 (referred to as "foot plates" in Japanese Patent No. 6752631) of a housing 110 (referred to as a "frame" in Japanese Patent No. 6752631) in a rotatable manner, and a pretensioner 130 is provided on one side wall 111.

[0004] The pretensioner 130 includes a drive wheel 131 (referred to as a "link member" in Japanese Patent No. 6752631) provided on one end side of the winding drum 120, a moving member 132 (referred to as a "rack" in Japanese Patent No. 6752631) that rotates the drive wheel 131 in a winding direction of the webbing 200 at the time of vehicle emergency, a pipe (a pressure container in a cylindrical shape) that houses the moving member 132, which is omitted from the drawing, at normal times, and a cover member 133 that houses the drive wheel 131. The moving member 132 moves inside the pipe and inside the cover member 133 by the pressure of gas supplied from a gas generator at the time of vehicle emergency and engages with a ratchet tooth of the drive wheel 131.

[0005] In addition, in the retractor 100, a lock base 140 (referred to as a "lock base" in Japanese Patent No. 6752631) is mounted to the winding drum 120 via the drive wheel 131. The lock base 140 rotates together with the winding drum 120 at normal times, and at the time of vehicle emergency, a pawl 150 held by the lock base 140 engages with an internal tooth formed in the cover member 133, thereby preventing rotation of the webbing 200 in a winding direction.

[0006] Also, in the retractor 100, the lock base 140 and the drive wheel 131 are restricted from moving to one side (the side of the winding drum 120) in the axial direction of the winding drum 120 by the peripheral edge portion of the drive wheel 131 abutting against the side wall 111, and the lock base 140 and the drive wheel 131 are restricted from moving to the other side (the side of the side wall 112) in the axial direction of the winding drum 120 by the pawl 150 abutting against the side wall 112. Figure 20 ​the other side (right side) in the axial direction of the take-up drum 120. In addition, by the step portion of the shaft portion of the lock base 140 abutting against the cover member 160 that houses the lock mechanism, movement of the lock base 140 and the drive wheel 131 to the other side (left side) in the axial direction of the take-up drum 120 is restricted. Figure 20 the other side (right side) in the axial direction of the take-up drum 120. In addition, by the step portion of the shaft portion of the lock base 140 abutting against the cover member 160 that houses the lock mechanism, movement of the lock base 140 and the drive wheel 131 to the other side (left side) in the axial direction of the take-up drum 120 is restricted. SUMMARY

[0007] In Japanese Patent No. 6752631, the direction of movement of the moving member 132 is not clearly described, but it can be considered to be a direction orthogonal to the axial direction of the take-up drum 120. However, in this case, when the pretensioner 130 operates, it is not determined to which side in the axial direction of the take-up drum 120 the lock base 140 and the drive wheel 131 move. That is, since the sliding resistance caused by the abutment for restricting the movement differs depending on the direction of movement, there is a possibility that the pulling force of the pretensioner on the webbing becomes unstable. Figure 20

[0008] Therefore, an object of the present application is to provide a seat belt retractor in which the pulling force of the pretensioner on the webbing can be stabilized.

[0009] The present application provides a seat belt retractor, which includes a housing having a pair of side walls facing each other, a take-up drum that winds a webbing and is housed between the pair of side walls so as to be rotatable in a winding direction and an unwinding direction of the webbing, a lock base that rotates together with the take-up drum at normal times and that blocks rotation in the unwinding direction at the time of vehicle emergency, and a pretensioner that rotates the take-up drum in the winding direction at the time of emergency, the pretensioner including a drive wheel provided on one end side of the take-up drum and rotating together with the take-up drum in the winding direction at least at an initial stage of the time of emergency, a pressure vessel provided on a side wall of the pair of side walls on the pretensioner side and having a tip end portion that is open at a position adjacent to the drive wheel and a base end portion provided with a gas generator, and a moving member that is housed in the pressure vessel at normal times and that rotates the drive wheel in the winding direction by being pushed out from the pressure vessel toward the opening direction of the tip end portion by gas generated by the gas generator at the time of emergency, the pressure vessel being provided such that the opening direction of the tip end portion is inclined with respect to a plane orthogonal to the axial direction of the take-up drum toward the take-up drum side or the opposite side of the take-up drum, and the moving member moving the lock base, the drive wheel, and the take-up drum in the axial direction of the take-up drum toward the opening direction of the tip end portion of the pressure vessel and causing any one of the lock base, the drive wheel, and the take-up drum to abut against a restriction member that is a part of the housing or a restriction member mounted to the housing at the time of operation of the pretensioner.​

[0010] According to the present application, there is provided a seat belt retractor capable of stabilizing the pulling force of a pretensioner on a webbing. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 is a perspective view of a seat belt retractor according to an embodiment of the present application.

[0012] Figure 2 is an exploded perspective view of the seat belt retractor shown in Figure 1

[0013] Figure 3 is a sectional view of the seat belt retractor shown in Figure 1

[0014] Figure 4 is a sectional view along the IV-IV line of Figure 3

[0015] Figure 5 is a sectional view along the V-V line of Figure 3

[0016] Figure 6 is a sectional view along the VI-VI line of Figure 4

[0017] Figure 7 is an exploded perspective view of a part of the take-up drum unit.

[0018] Figure 8 is an exploded perspective view of the remaining part of the take-up drum unit and a synchronization gear.

[0019] Figure 9 is a perspective view of the take-up drum.

[0020] Figure 10 is a perspective view of the drive wheel.

[0021] Figure 11 is a sectional view of the lock base.

[0022] Figure 12 is an exploded perspective view of the lock base and the lock member.

[0023] Figure 13 is an exploded perspective view of the lock base and the lock member when viewed from the opposite side.

[0024] Figure 14A indicates the state of the return spring when the lock member is in the non-engagement position, Figure 14B indicates the state of the return spring when the lock member is in the engagement position.

[0025] ​​​​​Figure 15 is a sectional view of a part of a seat belt retractor of a first modification example.

[0026] Figure 16 is a sectional view of a part of a seat belt retractor of a second modification example.

[0027] Figure 17 is a sectional view of a part of a seat belt retractor of a third modification example. Figure 6 corresponding to the third modification example.

[0028] Figure 18 is a sectional view of a part of a seat belt retractor of the third modification example.

[0029] Figure 19 is a sectional view of a part of a seat belt retractor of a fourth modification example.

[0030] Figure 20 is a sectional view of a conventional seat belt retractor.

[0031] BRIEF DESCRIPTION OF THE DRAWINGS

[0032] 1 seat belt retractor

[0033] 1C pretensioner

[0034] 10 webbing

[0035] 11 cover member (restricting member)

[0036] 12 pressure vessel

[0037] 12a distal end portion

[0038] 12b proximal end portion

[0039] 13 moving member

[0040] 17 cover member

[0041] 18 gas generator

[0042] 2 housing

[0043] 21 first side wall (restricting member)

[0044] 22 second side wall (restricting member)

[0045] 3 take-up drum

[0046] 31, 32 end face

[0047] 3A, 3C, 3E bushing (friction-reducing element)

[0048] 3D coating (friction-reducing element)

[0049] 5 drive wheels

[0050] 52 engagement teeth

[0051] 53 flange portion

[0052] 6 lock base

[0053] 71 first body portion (flange portion) DETAILED DESCRIPTION

[0054] Figure 1 and Figure 2 A seat belt retractor 1 according to an embodiment is shown. The seat belt retractor 1 prevents extraction of a webbing 10 as a seat belt at the time of a vehicle collision or the like.

[0055] Specifically, the seat belt retractor 1 includes a housing 2, a take-up spring unit 1A, a take-up drum unit IB, a pretensioner 1C, and a lock unit ID. The take-up drum unit IB includes a take-up drum 3 that takes up the webbing 10, and the housing 2 includes a first side wall 21 and a second side wall 22 that face each other in the axial direction of the take-up drum 3.

[0056] The take-up drum 3 is housed between the first side wall 21 and the second side wall 22 in a manner rotatable in the take-up direction and the extraction direction of the webbing 10. The housing 2 includes a back plate 23 that is perpendicular to the first side wall 21 and the second side wall 22 and is formed by sheet metal processing together with the first side wall 21 and the second side wall 22. However, the back plate 23 is not necessarily formed by sheet metal processing together with the first side wall 21 and the second side wall 22, and the first side wall 21 and the second side wall 22 that are separate from the back plate 23 can be attached to the back plate 23.

[0057] Hereinafter, for convenience of explanation, the axial direction of the take-up drum 3 is referred to as the left-right direction (the first side wall 21 side is set as the left side, and the second side wall 22 side is set as the right side), and the thickness direction of the back plate 23 is referred to as the front-rear direction (the side of the side walls 21, 22 is set as the front side, and the opposite side thereof is set as the rear side). In addition, as in the drawing of Figure 1 Figure 2 One of the directions orthogonal to the left-right direction and the front-rear direction is referred to as the upper side, and the other is referred to as the lower side, as in the drawing of

[0058] The lower portions of the front edges of the first side wall 21 and the second side wall 22 of the housing 2 are connected to each other, and the upper portions thereof are connected to each other by connecting rods 24, 25. Openings 21a, 22a through which the take-up drum 3 is inserted are provided in the first side wall 21 and the second side wall 22, respectively. In addition, an opening 23a that exposes the take-up drum 3 is provided in the back plate 23.

[0059] ​The take-up spring unit 1A is installed to the second side wall 22 of the housing 2, and the pretensioner 1C is installed to the first side wall 21. The lock unit 1D is installed to the pretensioner 1C.

[0060] As shown in Figure 3 , the take-up drum 3 has a first end face 31 on the first side wall 21 side of the housing 2 and a second end face 32 on the second side wall 22 side. In the present embodiment, the take-up drum 3 has a shaft portion 33 protruding to the right from the second end face 32, and the shaft portion 33 is rotatably supported to the take-up spring unit 1A. However, the torsion bar 4A described later can also penetrate the take-up drum 3, and the right end portion of the torsion bar 4A is rotatably supported to the take-up spring unit 1A. Note that the structure of the take-up spring unit 1A is known, and thus detailed description is omitted.

[0061] As shown in Figure 7 and Figure 8 , the take-up drum unit IB includes, in addition to the take-up drum 3, a bushing 3A, a bearing 3B, a torsion bar 4A, an impact energy absorbing wire 4B, a position limiting member 4C, a drive wheel 5, a lock base 6, a restoring spring 9A, and a rotation shaft 9B. The drive wheel 5 is also a constituent element of the pretensioner 1C. In other words, the drive wheel 5 is also included in the pretensioner 1C.

[0062] The bushing 3A and the bearing 3B are emergency mechanisms for smoothly rotating the take-up drum 3 even if the relative position of the take-up drum 3 with respect to the housing 2 is shifted at the time of emergency of the vehicle. As shown in Figure 3 , the bushing 3A is installed to the right end portion of the take-up drum 3 inside the opening 22a of the second side wall 22, and the bearing 3B is installed to the left end portion of the take-up drum 3 inside the opening 21a of the first side wall 21. Also, the bearing 3B includes a folded-back portion 3Ba (see Figure 7 ) that slides with respect to the drive wheel 5 at the time of relative rotation of the take-up drum 3 and the lock base 6, and is folded back to the inside of the left end portion of the take-up drum 3.

[0063] The take-up drum 3 has a central hole 30 extending along the center axis of the take-up drum 3. In the present embodiment, the central hole 30 has a bottom and is open only at the first end face 31. However, as described above, in the case where the torsion bar 4A penetrates the take-up drum 3, the central hole 30 can be open not only at the first end face 31 but also at the second end face 32.

[0064] The torsion bar 4A is inserted into the central hole 30 of the take-up drum 3. The lock base 6 described above is disposed in opposition to the first end face 31 of the take-up drum 3. One end side of the torsion bar 4A on the side opposite to the lock base 6 is coupled to the take-up drum 3 in a manner that cannot relatively rotate, and the other end side is coupled to the lock base 6 in a manner that cannot relatively rotate. Therefore, the lock base 6 rotates together with the take-up drum 3 at normal times.

[0065] More specifically, spline-shaped connecting portions 41 and 42 are respectively provided on one end and the other end of the torsion bar 4A. A spline-shaped recess for engaging with the connecting portion 41 is provided at the bottom of the center hole 30 of the winding roller 3, and the connecting portion 41 is fitted into the recess.

[0066] When the torsion bar 4A is prevented from rotating in the pull-out direction of the locking base 6, it undergoes plastic deformation when the pull-out force of the webbing 10 exceeds a specified value, allowing relative rotation between the take-up roller 3 and the locking base 6, and absorbing impact energy. In other words, in the initial stage of a vehicle emergency before the torsion bar 4A begins to plastic deform, the locking base 6 and the drive wheel 5 mounted on the locking base 6 rotate together with the take-up roller 3 in the take-up direction of the webbing 10.

[0067] The impact energy absorption line 4B absorbs impact energy in the initial stage when the take-up drum 3 and the locking base 6 rotate relative to each other. In this embodiment, as... Figure 9 As shown, the take-up roller 3 has two slots 35 that open on the first end face 31. In this embodiment, each slot 35 is a groove that is obliquely recessed from the outer peripheral surface of the take-up roller 3, but the slot 35 may also be a hole extending along the axial direction of the take-up roller 3. In addition, the number of slots 35 may also be one.

[0068] Impact energy absorption line 4B with head 43 (reference) Figure 7 The impact energy absorption line 4B is retracted into one of the slots 35 while protruding from the opening 36 of the slot 35. During the relative rotation of the winding roller 3 and the locking base 6, the impact energy absorption line 4B is drawn out while plastically deforming from the opening 36, thus absorbing impact energy. It should be noted that the impact energy absorption line 4B can be omitted.

[0069] The limiting member 4C specifies the allowable amount of relative rotation between the winding drum 3 and the locking base 6 when absorbing the impact energy of the torsion bar 4A. The limiting member 4C is held within the center hole 30 of the winding drum 3 so that it cannot rotate relative to the winding drum 3 and can move in the left and right directions.

[0070] like Figure 7 As shown, the limiting member 4C is a cylindrical shape through which the torsion bar 4A is inserted. An internal thread 47 is formed on the inner circumferential surface of the limiting member 4C.

[0071] In the present embodiment, the position-limiting member 4C includes a ring portion 45 and three claw portions 46 protruding to the right from the ring portion 45. On the other hand, three guide grooves 34 are provided in the central hole 30 of the winding drum 3. By the three claw portions 46 fitting into the three guide grooves 34 respectively, the position-limiting member 4C is held to the winding drum 3 in a manner that cannot rotate relative to the winding drum 3 and can move in the left-right direction. However, instead of the position-limiting member 4C including the claw portions 46, the cross-sectional shape of the outer shape of the position-limiting member 4C and the cross-sectional shape of the left end portion of the central hole 30 of the winding drum 3 can be polygonal.

[0072] As shown in Figs. 1 and 2, the winding drum 3 includes a cylindrical drum body 31 and a flange portion 32 protruding to the right from the drum body 31. The drum body 31 is provided with a central hole 30 in the center of the left end portion thereof. The flange portion 32 is provided with a plurality of (in the present embodiment, six as shown in Fig. 2) holding portions 33. The head portions 43 of the impact energy absorbing lines 4B described above are attached to the holding portions 33. Figure 3 Figure 8 As shown in Figs. 1 and 2, the winding drum 3 includes a cylindrical drum body 31 and a flange portion 32 protruding to the right from the drum body 31. The drum body 31 is provided with a central hole 30 in the center of the left end portion thereof. The flange portion 32 is provided with a plurality of (in the present embodiment, six as shown in Fig. 2) holding portions 33. The head portions 43 of the impact energy absorbing lines 4B described above are attached to the holding portions 33.

[0073] In the present embodiment, as shown in Figs. 1 and 2, the position-limiting member 4C is attached to the winding drum 3 in a manner that cannot rotate relative to the winding drum 3 and can move in the left-right direction. Figure 3 As shown in Figs. 1 and 2, the winding drum 3 includes a cylindrical drum body 31 and a flange portion 32 protruding to the right from the drum body 31. The drum body 31 is provided with a central hole 30 in the center of the left end portion thereof. The flange portion 32 is provided with a plurality of (in the present embodiment, six as shown in Fig. 2) holding portions 33. The head portions 43 of the impact energy absorbing lines 4B described above are attached to the holding portions 33.

[0074] Figure 8 As shown in Figs. 1 and 2, the winding drum 3 includes a cylindrical drum body 31 and a flange portion 32 protruding to the right from the drum body 31. The drum body 31 is provided with a central hole 30 in the center of the left end portion thereof. The flange portion 32 is provided with a plurality of (in the present embodiment, six as shown in Fig. 2) holding portions 33. The head portions 43 of the impact energy absorbing lines 4B described above are attached to the holding portions 33. Figure 10 As shown in Figs. 1 and 2, the winding drum 3 includes a cylindrical drum body 31 and a flange portion 32 protruding to the right from the drum body 31. The drum body 31 is provided with a central hole 30 in the center of the left end portion thereof. The flange portion 32 is provided with a plurality of (in the present embodiment, six as shown in Fig. 2) holding portions 33. The head portions 43 of the impact energy absorbing lines 4B described above are attached to the holding portions 33.

[0075] Figure 3 As shown in Figs. 1 and 2, the winding drum 3 includes a cylindrical drum body 31 and a flange portion 32 protruding to the right from the drum body 31. The drum body 31 is provided with a central hole 30 in the center of the left end portion thereof. The flange portion 32 is provided with a plurality of (in the present embodiment, six as shown in Fig. 2) holding portions 33. The head portions 43 of the impact energy absorbing lines 4B described above are attached to the holding portions 33. Figure 10 In the present embodiment, each of the holding portions 54 is a slot that opens to the radially outer side. The head portion 43 of the impact energy absorbing line 4B has an anti-disengagement portion 44 (see Fig. 3) that is located on the side opposite the winding drum 3 with respect to the flange portion 53 and is larger than the width of the slot that is the holding portion 54. However, each of the holding portions 54 can also be a hole that penetrates the flange portion 53.

[0076] Figure 7 In the present embodiment, each of the holding portions 54 is a slot that opens to the radially outer side. The head portion 43 of the impact energy absorbing line 4B has an anti-disengagement portion 44 (see Fig. 3) that is located on the side opposite the winding drum 3 with respect to the flange portion 53 and is larger than the width of the slot that is the holding portion 54. However, each of the holding portions 54 can also be a hole that penetrates the flange portion 53. ​​​​

[0077] As Figure 3 shown in the drawing, in the present embodiment, the driving wheel 5 abuts against the first end surface 31 of the take-up drum 3 through the rib 55. The impact energy absorbing wire 4B is drawn out from the opening 36 of the slot 35 while being wound around the rib 55. In addition, when the take-up drum 3 rotates relative to the lock base 6, in the axial direction of the take-up drum 3, the rib 55 of the driving wheel 5 contacts the first end surface 31 of the take-up drum 3, and in the radial direction of the take-up drum 3, the outer periphery of the flange portion 53 of the driving wheel 5 contacts the folded-back portion 3Ba of the bearing 3B mounted to the take-up drum 3, and the take-up drum 3 rotates relative to the driving wheel 5.

[0078] The pretensioner 1C rotates the driving wheel 5 in the take-up direction of the belt 10 at the time of emergency of the vehicle, thereby rotating the take-up drum 3 in the take-up direction of the belt 10 via the lock base 6 and the torsion bar 4A. As Figures 2-4 shown in the drawing, the pretensioner 1C includes a cover member 11 mounted to the first side wall 21 of the housing 2, a cylindrical pressure vessel 12 extending while being bent from the cover member 11, and a moving member 13 housed in the pressure vessel 12 at normal times.

[0079] As Figure 6 shown in the drawing, the pressure vessel 12 is provided to the first side wall 21 and the cover member 11 on the pretensioner 1C side. The cover member 11 houses the driving wheel 5 and the end portion 12a of the pressure vessel 12. The end portion 12a of the pressure vessel 12 is opened at a position adjacent to the driving wheel 5, and a gas generator 18 is provided in the base end portion 12b of the pressure vessel 12.

[0080] In the present embodiment, the pressure vessel 12 is provided so that the opening direction of the end portion 12a is inclined with respect to a surface orthogonal to the axial direction of the take-up drum 3 and facing the take-up drum 3 side. Therefore, the flange portion 53 of the driving wheel 5 is provided on the opening direction side of the end portion 12a of the pressure vessel 12 with respect to the engaging tooth 52 in the axial direction of the take-up drum 3. For example, the inclination angle of the end portion 12a with respect to the opening direction of the surface orthogonal to the axial direction of the take-up drum 3 is in the range of 5 to 15 degrees.

[0081] In the present embodiment, the moving member 13 is rod-shaped and plastically deforms by the engagement of the engaging tooth 52 of the driving wheel 5. However, the moving member 13 can also be composed of a plurality of divided bodies (for example, spheres) arranged at the same pitch as the engaging tooth 52 of the driving wheel 5.

[0082] The mobile member 13 is pushed out from the pressure vessel 12 toward the opening direction of the end portion 12a by the gas generated by the gas generator 18 at the time of vehicle emergency, and is engaged with the engagement teeth 52 of the drive wheel 5, so that the drive wheel 5 is rotated in the winding direction of the belt 10. Along with the rotation of the drive wheel 5, the lock base 6, the torsion bar 4A, and the winding drum 3 are also rotated. In addition, after the operation of the pretensioner 1C, the mobile member 13 is prevented from being pushed back into the pressure vessel 12 by the pressure of the gas in the pressure vessel 12, so that the drive wheel 5 is prevented from being rotated in the unwinding direction of the belt 10.

[0083] As shown in Figure 2 and Figure 5 , the cover member 11 is provided with an opening 11a through which the lock base 6 is inserted, and an internal tooth 11b is formed on the periphery of the opening 11a. On the other hand, the lock base 6 is provided with a pawl 61 which can be engaged with the internal tooth 11b. The pawl 61 is engaged with the internal tooth 11b at the time of vehicle emergency to prevent the lock base 6 from being rotated in the unwinding direction of the belt 10.

[0084] As shown in Figures 11-13 , the lock base 6 includes a first base member 7 on which the drive wheel 5 is mounted, and a second base member 8 which is mounted to the first base member 7 on the side opposite to the winding drum 3 in a non-rotatable manner with respect to the first base member 7. The pawl 61 is held between the first base member 7 and the second base member 8.

[0085] More specifically, the first base member 7 has a first main body portion 71 which is disc-shaped, and a protruding portion 72 which protrudes to the right from the first main body portion 71. As shown in Figure 3 , the drive wheel 5 is disposed between the first main body portion 71 and the first end surface 31 of the winding drum 3, and the protruding portion 72 penetrates the drive wheel 5. The root portion of the protruding portion 72 is formed in a hexagonal cross-sectional shape, and is fitted into a fitting hole of the same hexagonal cross-sectional shape in the main body portion 51 of the drive wheel 5, so that the drive wheel 5 is mounted to the first base member 7 in a non-rotatable manner. In addition, an external thread 73 described above is formed on the outer peripheral surface of the front end side of the protruding portion 72.

[0086] Further, the first base member 7 is provided with a first recess 74 which is recessed from the front end surface of the protruding portion 72, and a second recess 75 which is recessed from the surface of the first main body portion 71 on the side opposite to the drive wheel 5 coaxially with the first recess 74. The first recess 74 is a spline-shaped recess for engaging with the coupling portion 42 of the torsion bar 4A, and the coupling portion 42 is fitted into the first recess 74. In the present embodiment, the second recess 75 is circular in cross-section. In the present embodiment, the first base member 7 has a partition 76 which separates the first recess 74 and the second recess 75. That is, the first recess 74 and the second recess 75 have bottoms.

[0087] The second base member 8 has a plate-shaped second main body portion 81 that overlaps with the first main body portion 71 and a fitting protrusion 82 protruding to the right from the second main body portion 81. In this embodiment, three engaging recesses 87 are provided in the second main body portion 81. By engaging the engaging recesses 87 with the three engaging protrusions 79 provided in the first main body portion 71, the second base member 8 is mounted to the first base member 7 in a manner that prevents relative rotation. The cross-sectional shape of the engaging protrusion 82 is circular, and the engaging protrusion 82 engages with the second recess 75. However, it is also possible that the second recess 75 and the engaging protrusion 82 have non-circular cross-sectional shapes, and the engaging protrusion 82 engages with the second recess 75, thereby preventing relative rotation of the second base member 8 on the first base member 7. In this case, the engaging recesses 87 and engaging protrusions 79 can be omitted.

[0088] Furthermore, in this embodiment, the second main body portion 81 of the second base member 8 is provided with three riveting protrusions 85 protruding to the right, while the first main body portion 71 of the first base member 7 is provided with three through holes 77 through which the riveting protrusions 85 are inserted. A riveting recess 78, coaxial with the through holes 77 and with a diameter larger than the through holes 77, is formed on the side of the first main body portion 71 opposite to the second main body portion 81. Furthermore, the portion of each riveting protrusion 85 protruding from the through hole 77 is riveted within the riveting recess 78 to have an outer diameter larger than the through hole 77 and approximately the same as the inner diameter of the riveting recess 78 (in... Figure 12 , 13 In the middle, the riveting protrusion is depicted in its shape before riveting (85).

[0089] The pawl 61 has: a generally arc-shaped plate-shaped main body 62 held in the first main body 71 of the first base member 7 and the second main body 81 of the second base member 8; a plurality of (three in the illustration) engaging teeth 63 formed on the outer side of the main body 62 that can engage with the aforementioned internal teeth 11b; and an operating shaft 64 protruding to the left from the main body 62.

[0090] A pin 84 protruding to the left is provided on the second main body portion 81 of the second base member 8. For example... Figure 8 As shown, the aforementioned restoring spring 9A is approximately arc-shaped. One end of the restoring spring 9A engages with the operating shaft 64 of the pawl 61, and the other end engages with the pin 84. The restoring spring 9A serves to maintain the pawl 61 in position... Figure 14A The function of the non-engaged position shown.

[0091] Furthermore, the second base member 8 is provided with a locking hole 83 that opens to the left coaxially with the locking protrusion 82. In this embodiment, the locking hole 83 penetrates the second base member 8 and also opens to the right. The cross-sectional shape of the locking hole 83 is hexagonal.

[0092] The pawl 61 is operated by the synchronizing gear 14 (refer to Figure 2 , 8 ). As shown in Figure 2 , the lock unit ID includes a cover member 17 that houses the synchronizing gear 14 and a vehicle sensor 16. The synchronizing gear 14 is provided with a tape sensor 15. The tape sensor 15 operates when the tape 10 is sharply pulled out, thereby preventing the rotation of the synchronizing gear 14 in the pulling-out direction. The vehicle sensor 16 operates when the acceleration of the vehicle greatly changes, thereby preventing the rotation of the synchronizing gear 14 in the pulling-out direction.

[0093] When the rotation of the synchronizing gear 14 in the pulling-out direction is prevented, the lock base 6 relatively rotates with respect to the synchronizing gear 14 together with the take-up drum 3, the operation shaft 64 of the pawl 61 is operated by the guide hole 14a (refer to Figure 8 ) of the synchronizing gear 14, thereby the pawl 61 moves from the non-engagement position shown in Figure 14A to the engagement position shown in Figure 14B .

[0094] As shown in Figure 8 , the above-mentioned rotation shaft 9B has a bar-shaped main body portion 91 and an arm 92 that extends to the radially outer side from the main body portion 91. The right side portion of the main body portion 91 has a hexagonal cross-sectional shape, and is engaged with the engagement hole 83 of the second base member 8 to be engaged. The arm 92 is used to suppress the restoring spring 9A, and a hook 93 provided at the front end of the arm 92 is engaged with the engagement hole 86 provided at the second main body portion 81 of the second base member 8. As shown in Figure 3 , the left side portion of the rotation shaft 9B penetrates the synchronizing gear 14, and is supported by the cover member 17 of the lock unit ID to be rotatable.

[0095] Next, the effect of the inclination of the opening direction of the end portion 12a of the pressure container 12 will be described. When the pretensioner 1C operates, the moving member 13 that is pushed out from the pressure container 12 to the opening direction of the end portion 12a abuts against the flange portion 53 of the drive wheel 5, and presses the flange portion 53 in the axial direction of the take-up drum 3 to the opening direction of the end portion 12a of the pressure container 12, that is, to the right side. In addition, the moving member 13 also abuts against the bearing 3B that is located radially outward of the flange portion 53, and presses the first end surface 31 of the take-up drum 3 to the right side via the bearing 3B. As a result, the drive wheel 5, the lock base 6, and the take-up drum 3 are moved to the right side by the moving member 13, and the right end portion of the take-up drum 3 abuts against the second side wall 22 of the housing 2 via the bush 3A.

[0096] That is, the second side wall 22 that is a part of the housing 2 functions as a restriction member that restricts movement of the drive wheel 5, the locking base 6, and the take-up drum 3 in the axial direction of the take-up drum 3. In addition, the bush 3A is a friction reduction element that intervenes between the take-up drum 3 and the second side wall 22 and reduces the sliding resistance that occurs due to the abutment of the take-up drum 3 and the second side wall 22. The friction reduction element can be any element that has good sliding properties compared to the take-up drum 3 and the second side wall 22, and in the case where the housing 2 and the take-up drum 3 are composed of metal (for example, steel, aluminum alloy) as in the present embodiment, the bush 3A is composed of a material (for example, fluororesin, polyacetal, polypropylene, or the like) that has good sliding properties compared to metal.

[0097] As explained above, in the seat belt retractor 1 of the present embodiment, when the pretensioner 1C is operating, the moving member 13 causes the take-up drum 3 to abut against the restriction member that is the second side wall 22 of the housing 2 via the bush 3A, and thus the movement restriction state of the locking base 6, the drive wheel 5, and the take-up drum 3 in the axial direction of the take-up drum 3 is determined. Therefore, it is possible to stabilize the pulling force of the pretensioner 1C on the webbing 10.

[0098] Furthermore, in the present embodiment, the moving member 13 presses the flange portion 53 of the drive wheel 5 and the first end surface 31 of the take-up drum 3 via the bearing 3B, and thus the take-up drum 3 is caused to abut against the restriction member via the bush 3A by the pressing force of the moving member 13 against the flange portion 53 of the drive wheel 5 and the first end surface 31 of the take-up drum 3.

[0099] Furthermore, in the present embodiment, the restriction member is the second side wall 22 of the housing 2, and thus an existing component functions as the restriction member. Therefore, it is not necessary to add a new component as the restriction member. Furthermore, it is possible to use the housing 2 that has sufficient strength as the restriction member.

[0100] In addition, in the present embodiment, since the bush 3A is adopted as the friction reduction element, the friction between the take-up drum 3 and the restriction member is reduced when the pretensioner 1C is operating. Therefore, it is possible to sufficiently ensure the pulling force of the pretensioner 1C on the webbing 10. Furthermore, if the friction reduction element is the bush 3A, it is possible to make the friction reduction element a simple structure.

[0101] <MODIFIED EXAMPLE>

[0102] The present application is not limited to the above-described embodiments, and various modifications can be made within the scope of the present application without departing from the spirit of the present application.

[0103] For example, the locking base 6 does not necessarily need to hold the pawl 61, and can be a ratchet that engages with a pawl held by the housing 2.

[0104] Alternatively, the pretensioner 1C can also be disposed on the side opposite to the locking base 6, i.e., the second side wall 22 of the housing 2, relative to the take-up drum 3. In this case, the drive wheel 5 can also be disposed on the left end side of the take-up drum 3 via a clutch. The clutch disposed in this way allows the drive wheel 5 to rotate relative to the take-up drum 3 under normal conditions, and allows the drive wheel 5 to rotate together with the take-up drum 3 in the event of a vehicle emergency. That is, the drive wheel 5 can rotate together with the take-up drum 3 in the take-up direction of the webbing 10, at least initially in the event of a vehicle emergency.

[0105] In the case where the pretensioner 1C is provided on the first side wall 21 as described in the above embodiment, a clutch may also be provided between the locking base 6 and the drive wheel 5. Under normal circumstances, the drive wheel 5 and the locking base 6 rotate relative to each other, and in the event of a vehicle emergency, the drive wheel 5 and the locking base 6 rotate together.

[0106] The pretensioner 1C can also be disposed on the inner side of the housing 2 (between the first sidewall 21 and the second sidewall 22), opposite to the above embodiment. For example, the cover member 11 of the pretensioner 1C can also be installed on the inner side of the first sidewall 21, and the internal teeth that engage with the pawl 61 are disposed on the first sidewall 21.

[0107] Alternatively, the drive wheel 5 may not have a flange 53, and the moving member 13 may abut against the first end face 31 of the winding roller 3 when the pretensioner 1C is operating, pressing the first end face 31 against the opening direction of the end portion 12a of the pressure vessel 12 in the axial direction of the winding roller 3, i.e., on the right side. According to this structure, the pressing force of the moving member 13 relative to the first end face 31 of the winding roller 3 can cause the winding roller 3 to abut against the second sidewall 22, which serves as a limiting member.

[0108] like Figure 15 In the first modified example shown, similar to a seatbelt retractor, a flange portion 37 extending radially outward from the left end of the take-up roller 3, positioned to the left of the first sidewall 21, is provided, and a bushing 3C is installed in the opening 21a of the first sidewall 21. The flange portion 37 is opposite to the periphery of the opening 21a of the first sidewall in the left-right direction. That is, in the first modified example, the first sidewall 21, which is part of the housing 2, is a limiting member, and the bushing 3C is a friction-reducing element between the take-up roller 3 and the limiting member.

[0109] Or, it can be like Figure 16In the second variation shown, the seat belt retractor has a flange 57 on the drive wheel 5 that extends radially outward in a manner opposite to the periphery of the opening 21a of the first sidewall 21 in the left-right direction, and a bushing 3C is installed in the opening 21a of the first sidewall 21. That is, in the second variation, the first sidewall 21, which is part of the housing 2, is a limiting member, and the bushing 3C is a friction-reducing element between the drive wheel 5 and the limiting member.

[0110] exist Figure 16 In the process of pretensioner 1C operating, the moving member 13, which extends from pressure vessel 12 toward the opening of end portion 12a, abuts against the flange portion 53 and flange portion 57 of drive wheel 5, pressing the flange portion 53 and flange portion 57 toward the opening side of end portion 12a of pressure vessel 12, i.e., the right side, in the axial direction of winding drum 3. As a result, through the moving member 13, drive wheel 5, locking base 6, and winding drum 3 move to the right, and flange portion 57 abuts against first sidewall 21 via bushing 3C.

[0111] like Figure 17 As shown in the third modified example of the seat belt retractor, the pressure vessel 12 can also be configured such that the opening direction of the end portion 12a is tilted to the left, opposite to the side of the winding roller 3, which is the side orthogonal to the axial direction of the winding roller 3.

[0112] In this case, such as Figure 18 As shown, the outer peripheral portion of the first main body portion 71 of the first base member 7 of the locking base 6, which is radially outer of the protrusion 72, can also be regarded as the flange portion on the opening direction side of the end portion 12a of the pressure vessel 12, i.e., the left side, which is provided relative to the engagement tooth 52 of the drive wheel 5 in the axial direction of the winding drum 3.

[0113] Furthermore, the portion of the first main body 71 of the first base member 7 of the locking base 6 that is radially outward of the protrusion 72 is opposed in the left-right direction to the periphery of the opening 11a in the cover member 11 of the pretensioner 1C. That is, the cover member 11 functions as a limiting member to restrict the movement of the drive wheel 5, the locking base 6, and the winding drum 3 in the axial direction of the winding drum 3.

[0114] Furthermore, on the right-side surface of the periphery of the opening 11a in the cover member 11, a coating 3D is applied as a friction-reducing element to reduce the sliding resistance caused by the contact between the locking base 6 and the cover member 11. The coating 3D is made of a material with good sliding properties (e.g., a material containing fluororesin, molybdenum disulfide, graphite, etc.).

[0115] exist Figure 18In the pre-tensioner 1C, when the pre-tensioner 1C is operated, the moving member 13 pushed out from the pressure vessel 12 in the opening direction of the end portion 12a abuts against the outer peripheral edge portion (flange portion) of the first main body portion 71 of the first base member 7 of the lock base 6, and presses the outer peripheral edge portion of the first main body portion 71 in the axial direction of the take-up drum 3 to the opening direction side of the end portion 12a of the pressure vessel 12, that is, to the left side. As a result, the moving member 13, the drive wheel 5, the lock base 6, and the take-up drum 3 are moved to the left side, and the outer peripheral edge portion of the first main body portion 71 abuts against the cover member 11 via the coating 3D.

[0116] That is, in the third modification shown in FIG. 9, the movement restriction state of the lock base 6, the drive wheel 5, and the take-up drum 3 in the axial direction of the take-up drum 3 is determined as in the above-described embodiment. Therefore, the pulling force of the pre-tensioner 1C on the webbing 10 can be stabilized. Figure 18

[0117] Further, in the third modification, since the moving member 13 presses the outer peripheral edge portion of the first main body portion 71 of the first base member 7, the outer peripheral edge portion of the first main body portion 71 can abut against the cover member 11 (the restriction member) via the coating 3D by the pressing force of the moving member 13 against the outer peripheral edge portion of the first main body portion 71.

[0118] Further, in the third modification, the restriction member is the cover member 11, and thus an existing component functions as the restriction member. Therefore, a new component as the restriction member does not need to be added. Further, the cover member 11 having sufficient strength can be used as the restriction member.

[0119] Further, in the third modification, since the coating 3D is used as the friction reduction element, the friction between the lock base 6 and the restriction member can be reduced when the pre-tensioner 1C is operated. Therefore, the pulling force of the pre-tensioner 1C on the webbing 10 can be sufficiently ensured. Further, if the friction reduction element is the coating 3D, the friction reduction element can be a simple structure.

[0120] In the case where the pressure vessel 12 is provided so as to be inclined to the left side in the opening direction of the end portion 12a, as in the fourth modification shown in FIG. 10, a flange portion 38 extending to the radial outer side at a position to the right side of the first side wall 21 can be provided at the left end portion of the take-up drum 3, and a bushing 3E can be attached to the opening 21a of the first side wall 21. The flange portion 38 opposes the peripheral edge portion of the opening 21a of the first side wall in the left-right direction. That is, in the fourth modification, the first side wall 21 as a part of the housing 2 is the restriction member, and the bushing 3E is the friction reduction element interposed between the take-up drum 3 and the restriction member. Figure 19

[0121] ​​In the above-described embodiments, the bush 3A can also be provided to the second side wall 22 instead of being provided to the right end portion of the winding drum 3. In the first modification example, the bush 3C can also be provided to the left end portion of the winding drum 3 instead of being provided to the first side wall 21. In the second modification example, the bush 3C can also be provided to the drive wheel 5 instead of being provided to the first side wall 21. In the third modification example, the coating 3D can also be applied to the surface of the first main body portion 71 of the first base member 7 of the lock base 6 instead of being applied to the surface of the cover member 11. In the fourth modification example, the bush 3E can also be provided to the left end portion of the winding drum 3 instead of being provided to the first side wall 21. Also, instead of the bush, a coating can be used, and instead of the coating, a bush can be used.

[0122] Further, when the pre-tensioner 1C is operated, the moving member 13 can abut against the engagement teeth 52 of the drive wheel 5 other than the drive wheel 5, and only the drive wheel 5, the lock base 6, and the winding drum 3 can be moved in the axial direction of the winding drum 3 to the opening direction of the end portion 12a of the pressure container 12 by the frictional force.

[0123] <OVERVIEW>

[0124] As a first aspect, the present application provides a seat belt retractor, including: a housing having a pair of side walls facing each other; a winding drum that winds a webbing and is housed between the pair of side walls so as to be rotatable in a winding direction and an extraction direction of the webbing; a lock base that rotates together with the winding drum at normal times and prevents rotation in the extraction direction at vehicle emergency; a pre-tensioner that rotates the winding drum in the winding direction at the emergency, the pre-tensioner including: a drive wheel provided on one end side of the winding drum and rotating together with the winding drum in the winding direction at least at an initial stage of the emergency; a pressure container of a cylindrical shape provided to a side wall of the pre-tensioner among the pair of side walls and having an end portion that opens at a position adjacent to the drive wheel and a base end portion provided with a gas generator; and a moving member that is housed in the pressure container at normal times and rotates the drive wheel in the winding direction by engaging with the drive wheel while being pushed out from the pressure container to an opening direction of the end portion by gas generated by the gas generator at the emergency, the pressure container being provided so that the opening direction of the end portion is inclined to the side of the winding drum or the opposite side of the winding drum with respect to a plane orthogonal to the axial direction of the winding drum, the moving member moving the lock base, the drive wheel, and the winding drum in the axial direction of the winding drum to the opening direction of the end portion of the pressure container at operation of the pre-tensioner, and any one of the lock base, the drive wheel, and the winding drum abutting against a restriction member that is a part of the housing or a restriction member attached to the housing.

[0125] According to the above-described structure, when the pretensioner operates, the moving member abuts against any one of the lock base, the drive wheel, and the take-up drum against the restriction member, and thus the movement restriction state of the lock base, the drive wheel, and the take-up drum in the axial direction of the take-up drum is determined. Therefore, it is possible to stabilize the pulling force of the pretensioner on the webbing.

[0126] As a second aspect, in the first aspect, the drive wheel can have an engagement tooth for engaging with the moving member, and a flange portion provided on the opening direction side of the end portion of the pressure container with respect to the engagement tooth in the axial direction of the take-up drum, the moving member abutting against the flange portion when the pretensioner operates and pressing the flange portion toward the opening direction side of the end portion of the pressure container in the axial direction of the take-up drum. According to this structure, any one of the lock base, the drive wheel, and the take-up drum can be abutted against the restriction member by the pressing force of the moving member against the flange portion of the drive wheel.

[0127] As a third aspect, in the first or second aspect, the moving member can abut against an end surface of the take-up drum when the pretensioner operates and press the end surface toward the opening direction side of the end portion of the pressure container in the axial direction of the take-up drum. According to this structure, any one of the lock base, the drive wheel, and the take-up drum can be abutted against the restriction member by the pressing force of the moving member against the end surface of the take-up drum.

[0128] As a fourth aspect, in the first or second aspect, the drive wheel can be provided on the one end side of the take-up drum via the lock base, and have an engagement tooth for engaging with the moving member, the lock base having a flange portion provided on the opening direction side of the end portion of the pressure container with respect to the engagement tooth in the axial direction of the take-up drum, the moving member abutting against the flange portion when the pretensioner operates and pressing the flange portion toward the opening direction side of the end portion of the pressure container in the axial direction of the take-up drum. According to this structure, any one of the lock base, the drive wheel, and the take-up drum can be abutted against the restriction member by the pressing force of the moving member against the flange portion of the lock base.

[0129] As a fifth aspect, in any one of the first to fourth aspects, the restriction member can be one of the pair of side walls of the housing. According to this structure, an existing component functions as the restriction member, and thus a new component as the restriction member is not required to be added. Moreover, the housing having sufficient strength can be used as the restriction member.

[0130] As a sixth aspect, in any one of the first to fourth aspects, the pretensioner can further include a cover member that houses the drive wheel and the end portion of the pressure container and is attached to the housing, and the restriction member can be the cover member. According to this structure, an existing component functions as the restriction member, so a new component as the restriction member does not need to be added. Also, the cover member having sufficient strength can be used as the restriction member.

[0131] As a seventh aspect, in any one of the first to sixth aspects, the seat belt retractor can further include a friction reduction element that reduces sliding resistance generated by the abutment of any one of the lock base, the drive wheel, and the take-up drum against the restriction member. According to this structure, the friction between any one of the lock base, the drive wheel, and the take-up drum and the restriction member is reduced when the pretensioner operates. Therefore, the pulling force of the pretensioner on the webbing can be sufficiently ensured.

[0132] As an eighth aspect, in the seventh aspect, the friction reduction element can be a bushing interposed between any one of the lock base, the drive wheel, and the take-up drum and the restriction member, or a coating on the surface of any one of the lock base, the drive wheel, the take-up drum, and the restriction member. According to this structure, the friction reduction element can be a simple structure.

Claims

1. A seat belt retractor, wherein the seat belt retractor is provided with: a housing having a pair of side walls opposed to each other; a winding drum that winds a webbing and is housed between the pair of side walls in a manner capable of rotating in a winding direction and an extraction direction of the webbing; a lock base that rotates together with the winding drum at normal times, and that stops rotation in the extraction direction at vehicle emergency times; a pretensioner that rotates the winding drum in the winding direction at the emergency times, the pretensioner includes: a drive wheel that is provided on one end side of the winding drum, and that rotates together with the winding drum in the winding direction at least at an initial stage of the emergency times; a pressure container that is provided on a side wall of the pair of side walls on the pretensioner side, and that has a tip end portion that is opened at a position adjacent to the drive wheel, and a base end portion that is provided with a gas generator; and a moving member that is housed in the pressure container at normal times, and that rotates the drive wheel in the winding direction by being pushed out from the pressure container toward an opening direction of the tip end portion by gas generated by the gas generator at the emergency times, the pressure container is provided so that the opening direction of the tip end portion is inclined with respect to a plane that is orthogonal to an axial direction of the winding drum and faces the winding drum side or the opposite side of the winding drum, at the operation of the pretensioner, the moving member moves the lock base, the drive wheel, and the winding drum in the axial direction of the winding drum to the opening direction side of the tip end portion of the pressure container, and makes any one of the lock base, the drive wheel, and the winding drum abut against a restriction member that is a part of the housing or a restriction member that is attached to the housing.

2. The seat belt retractor according to claim 1, wherein the drive wheel has an engagement tooth for engaging with the moving member, and a flange portion that is provided on the opening direction side of the tip end portion of the pressure container with respect to the engagement tooth in the axial direction of the winding drum, the moving member abuts against the flange portion at the operation of the pretensioner, and presses the flange portion to the opening direction side of the tip end portion of the pressure container in the axial direction of the winding drum.

3. The seat belt retractor according to claim 1, wherein the moving member abuts against an end surface of the winding drum at the operation of the pretensioner, and presses the end surface to the opening direction side of the tip end portion of the pressure container in the axial direction of the winding drum.

4. The seat belt retractor according to claim 1, wherein the drive wheel is provided on one end side of the winding drum via the lock base, and has an engagement tooth for engaging with the moving member, the lock base has a flange portion that is provided on the opening direction side of the tip end portion of the pressure container with respect to the engagement tooth in the axial direction of the winding drum, The moving member abuts against the flange portion when the pretensioner operates, and presses the flange portion toward the opening direction side of the end portion of the pressure container in the axial direction of the winding drum.

5. The seat belt retractor according to claim 1, wherein The limiting member is one of the pair of side walls of the housing.

6. The seat belt retractor according to claim 1, wherein The pretensioner includes a cover member that houses the drive wheel and the end portion of the pressure container, and is installed to the housing. The limiting member is the cover member.

7. The seat belt retractor according to any one of claims 1 to 6, wherein The seat belt retractor further has a friction reduction element that reduces the sliding resistance generated by the abutment of any one of the lock base, the drive wheel, and the winding drum against the limiting member.

8. The seat belt retractor according to claim 7, wherein The friction reduction element is a bushing interposed between any one of the lock base, the drive wheel, and the winding drum and the limiting member, or a coating on the surface of the lock base, the drive wheel, the winding drum, and the limiting member.

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