CN118618254A - Seat belt retractor - Google Patents

Abstract

A seat belt retractor comprises: a shell, the shell comprising a first side wall and a second side wall facing each other; a reel, the reel being configured to reel up a belt; a locking base; a torsion bar, the torsion bar comprising an end side and another end side, the one end side being opposite to the locking base, the one end side being coupled to the reel and being non-rotatable relative to the reel, the other end side being coupled to the locking base and being non-rotatable relative to the locking base; a pretensioner, the pretensioner comprising a pretensioner housing attached to the first side wall and a driving wheel attached to the locking base; a locking member, the locking member being located in the locking base; and a stop member being screwed onto a male thread of the locking base.

Description

Seat belt retractor

Technical Field

The present disclosure relates to a seat belt retractor that can remove slack in webbing and absorb impact energy of an occupant in an emergency situation such as a vehicle collision.

Background Art

In the related art, a seat belt retractor is known that prevents a webbing from being pulled out in an emergency situation of a vehicle. In the seat belt retractor, a reel configured to reel in the webbing is rotatably accommodated between a pair of side walls of a housing.

For example, WO2010/107075A1 discloses a seat belt retractor, which includes a pretensioner and a torsion bar. The pretensioner is configured to rotate a reel (referred to as a "spindle" in WO2010/107075A1) in a retracting direction in an emergency situation of the vehicle, and the torsion bar is configured to absorb impact energy by plastic deformation caused by torsion.

Specifically, in the seat belt retractor disclosed in WO2010/107075A1, the reel has a central hole opened in one end surface, and a locking base (referred to as a "tread head" in WO2010/107075A1) is arranged to face the end surface. A torsion bar is inserted into the central hole of the reel, and one end side of the torsion bar is opposite to the locking base and is coupled to the reel and cannot rotate relative to the reel, and the other end side of the torsion bar is coupled to the locking base and cannot rotate relative to the locking base.

In addition, a stop member (referred to as a "hexagonal nut" in WO2010/107075A1) is held in the central hole of the reel and is non-rotatable relative to the reel and is movable in the axial direction of the reel. The locking base is formed with a male thread screwed together with the stop member. The stop member limits the amount of relative rotation that can be allowed between the reel and the locking base when the torsion bar absorbs impact energy.

In an emergency situation of the vehicle, the locking base is prevented from rotating in the pulling-out direction, and in this state, when the pulling-out force of the belt exceeds a predetermined value, the torsion bar is plastically deformed, and the reel is rotated relative to the locking base in the pulling-out direction. At this time, the relative rotation between the reel and the locking base is restricted to a predetermined amount by the stop member. Accordingly, when absorbing impact energy, the pulling-out amount of the belt is restricted, and the occupant is prevented from moving in the forward direction beyond a predetermined distance.

In the seat belt retractor of WO2010/107075A1, the pretensioner is provided on the side opposite to the locking base, and JP2012-500158A discloses a seat belt retractor in which the pretensioner is provided on the same side as the locking base. In the seat belt retractor of JP2012-500158A, the driving wheel of the pretensioner is attached to the locking base (referred to as a "tread head" in JP2012-500158A). However, a stopper member is not adopted in the seat belt retractor of JP2012-500158A.

In the seat belt retractor of WO2010/107075A1, in order to change the position of the pretensioner to the same side as the locking base as in JP2012-500158A, it is necessary to attach the driving wheel to the locking base. However, in the seat belt retractor of WO2010/107075A1 including the stopper member, the locking base is formed of a material having high strength in order to ensure the strength of a portion in which a male thread is formed in the locking base. Therefore, in order to attach the driving wheel to the locking base in the seat belt retractor of WO2010/107075A1, there are problems that the locking base is enlarged in the axial direction of the reel and the locking base becomes complicated in shape, making it difficult to manufacture the locking base.

Summary of the invention

An aspect of a non-limiting embodiment of the present disclosure is directed to a seat belt retractor capable of easily manufacturing a locking base and having a configuration in which a stopper member is used and a pretensioner is provided on the same side as the locking base.

Certain aspects of the non-limiting embodiments of the present disclosure relate to the features discussed above and/or other features not described above. However, it is not necessary for aspects of the non-limiting embodiments to relate to the above features, and aspects of the non-limiting embodiments of the present disclosure may not relate to the features described above.

According to one aspect of the present disclosure, there is provided a seat belt retractor, the seat belt retractor comprising:

a housing including a first side wall and a second side wall facing each other;

a take-up drum configured to take up a belt-like object, the take-up drum being accommodated between the first side wall and the second side wall so as to be rotatable in a take-up direction and a pull-out direction of the belt-like object, the take-up drum having a central hole opened on a first end surface of the take-up drum, the first end surface of the take-up drum being located on one side of the first side wall;

a locking base, the locking base being arranged to face the first end surface of the reel;

a torsion bar, the torsion bar being inserted into the central hole of the take-up drum, the torsion bar including one end side and the other end side, the one end side being opposite to the locking base, the first end side being coupled to the take-up drum and being non-rotatable relative to the take-up drum, the other end side being coupled to the locking base and being non-rotatable relative to the locking base, the torsion bar being configured to plastically deform in a state where the locking base is prevented from rotating in the pulling-out direction and when the pulling-out force of the webbing exceeds a predetermined value, so as to absorb impact energy while allowing relative rotation between the take-up drum and the locking base;

a pretensioner including a pretensioner housing attached to the first side wall and a drive wheel attached to the locking base, the pretensioner being configured to rotate the reel drum in the reeling direction via the drive wheel, the locking base, and the torsion bar in an emergency situation of the vehicle;

a lock member located in the locking base, the lock member being configured to engage with the first side wall or the pretensioner housing to prevent the locking base from rotating in the pulling direction in the emergency situation of the vehicle; and

a stop member, the stop member being held in the central hole of the reel and being non-rotatable relative to the reel and being movable in the axial direction of the reel, the stop member being screwed onto the male thread of the locking base, the stop member being configured to limit an allowable relative rotation amount between the reel and the locking base when the torsion bar absorbs the impact energy,

wherein the locking base comprises a first base member and a second base member, the driving wheel being attached to the first base member, the second base member being attached to the first base member on a side of the first base member opposite to the reel and being non-rotatable relative to the first base member, the second base member being configured to hold the lock member between the first base member and the second base member,

The first base member comprises:

a disc-shaped first body portion, wherein the drive wheel is disposed between the first body portion and the first end surface of the take-up drum; and

a protrusion, the protrusion protruding from the first main body portion along a second direction of the axial direction of the take-up drum to penetrate the driving wheel, the second direction being a direction toward the second side wall,

The male thread is formed on the outer circumferential surface of the distal end side of the protrusion,

The first base member further comprises:

a first recess recessed from a distal end surface of the protrusion, the first recess configured to be coupled to the torsion bar; and

a second recessed portion, the second recessed portion being recessed from a surface of the first body portion on a side opposite to the driving wheel, the second recessed portion being coaxial with the first recessed portion, and

The second base member comprises:

a plate-shaped second main body portion, the second main body portion overlapping the first main body portion; and

A fitting protrusion protrudes from the second body portion in the second direction, the fitting protrusion being fitted into the second recess.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more exemplary embodiments of the present invention will be described in detail based on the accompanying drawings, in which:

FIG. 1 is a perspective view of a seat belt retractor according to an embodiment of the present disclosure;

FIG2 is an exploded perspective view of the seat belt retractor illustrated in FIG1 ;

FIG3 is a cross-sectional view of the seat belt retractor illustrated in FIG1 ;

FIG4 is a cross-sectional view taken along line IV-IV in FIG3;

Fig. 5 is a cross-sectional view taken along line V-V in Fig. 3;

FIG6 is an exploded perspective view of a portion of the take-up drum unit;

FIG7 is an exploded perspective view of the remaining parts of the take-up drum unit and the synchronization gear;

FIG8 is a perspective view of the reel;

Fig. 9 is a perspective view of a driving wheel;

FIG10 is an exploded perspective view of the locking base and the lock member;

FIG11 is an exploded perspective view of the locking base and the lock member viewed from the opposite side;

FIG12 is a perspective view of the locking base;

FIG13 is a cross-sectional view taken along line XIII-XIII in FIG12;

FIG14 is a cross-sectional view taken along line XIV-XIV in FIG12;

FIG15 is a cross-sectional view taken along line XV-XV in FIG14;

FIG16A illustrates the state of the return spring when the lock member is in the non-engaged position;

FIG. 16B illustrates the state of the return spring with the lock member in the engaged position; and

17 is a cross-sectional view corresponding to FIG. 14 of a locking base to which a torsion bar according to a first variation is assembled;

FIG. 18 is a cross-sectional view corresponding to FIG. 13 of a locking base according to a second modification.

DETAILED DESCRIPTION

1 and 2 illustrate a seat belt retractor 1 according to an embodiment of the present disclosure. The seat belt retractor 1 is configured to prevent a webbing 10, which is a seat belt, from being pulled out in an emergency situation such as a vehicle collision.

Specifically, the seat belt retractor 1 includes a housing 2, a take-up spring unit 1A, a take-up drum unit 1B, a pretensioner 1C, and a locking unit 1D. The take-up drum unit 1B includes a take-up drum 3 configured to take up a belt 10. The housing 2 includes a first side wall 21 and a second side wall 22 facing each other in the axial direction of the take-up drum 3.

The take-up drum 3 is accommodated between the first side wall 21 and the second side wall 22 so as to be rotatable in the take-up direction and the pull-out direction of the webbing 10. In the axial direction of the take-up drum 3, the direction toward the first side wall 21 is the first direction, and the direction toward the second side wall 22 opposite to the first direction is the second direction.

The housing 2 includes a back plate 23, which is formed by sheet metal processing together with the first side wall 21 and the second side wall 22, and is perpendicular to the first side wall 21 and the second side wall 22. Hereinafter, for the convenience of description, the axial direction of the take-up drum 3 is referred to as the left-right direction (the first direction is referred to as the left direction, and the second direction is referred to as the right direction), and the thickness direction of the back plate 23 is referred to as the front-back direction (one side of the side walls 21 and 22 is referred to as the forward direction, and the opposite side is referred to as the rearward direction). As illustrated in FIGS. 1 and 2, one side of the direction orthogonal to the left-right direction and the front-back direction is referred to as the upward direction, and the other side of the direction orthogonal to the left-right direction and the front-back direction is referred to as the downward direction.

The lower and upper portions of the front sides of the first side wall 21 and the second side wall 22 of the housing 2 are connected by connecting rods 24 and 25. The first side wall 21 and the second side wall 22 are respectively provided with openings 21a and 22a through which the reel 3 is inserted. The back plate 23 is provided with an opening 23a through which the reel 3 is exposed.

The retractor spring unit 1A is attached to the second side wall 22. The pretensioner 1C is attached to the first side wall 21 of the housing 2. The locking unit 1D is attached to the pretensioner 1C.

As illustrated in FIG3 , the take-up drum 3 includes a first end surface 31 located on one side of the first side wall 21 of the housing 2 and a second end surface 32 located on one side of the second side wall 22 of the housing 2. In the present embodiment, the take-up drum 3 includes a shaft portion 33 protruding from the second end surface 32 in the right direction, and the shaft portion 33 is supported by the take-up spring unit 1A in a rotatable manner. However, the torsion bar 4A to be described later may penetrate the take-up drum 3, and the right end portion of the torsion bar 4A may be supported by the take-up spring unit 1A in a rotatable manner. Since the construction of the take-up spring unit 1A is known, a detailed description thereof will be omitted.

As illustrated in Figures 6 and 7, the reel unit 1B includes a bushing 3A, a bearing 3B, a torsion bar 4A, an impact energy absorbing wire 4B, a stop member 4C, a drive wheel 5, a locking base 6, a return spring 9A, and a rotating shaft 9B in addition to the reel 3. The drive wheel 5 is also a component of the pretensioner 1C. In other words, the drive wheel 5 is included in the pretensioner 1C.

The bushing 3A and the bearing 3B are emergency devices for smoothly rotating the reel 3 even when the relative position of the reel 3 with respect to the housing 2 is displaced in an emergency situation of the vehicle. As illustrated in FIG. 3 , the bushing 3A is attached to the right end portion of the reel 3 positioned inside the opening 22a of the second side wall 22, and the bearing 3B is attached to the left end portion of the reel 3 positioned in the opening 21a of the first side wall 21. In addition, the bearing 3B includes a folding portion 3Ba (see FIG. 6 ) which is folded back to the inside of the left end portion of the reel 3. The folding portion 3Ba is configured to slide together with the drive wheel 5 which is attached to the locking base 6 and cannot rotate when the reel 3 and the locking base 6 rotate relative to each other.

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

The torsion bar 4A is inserted into the center hole 30 of the take-up drum 3. The locking base 6 is arranged to face the first end surface 31 of the take-up drum 3. The torsion bar 4A includes one end side opposite to the locking base 6, which is coupled to the take-up drum 3 and cannot rotate relative to the take-up drum 3, and the other end side of the torsion bar 4A is coupled to the locking base 6 and cannot rotate relative to the locking base 6.

More specifically, the torsion bar 4A includes spline-shaped coupling parts 41 and 42 at one end and the other end, respectively. The bottom of the center hole 30 of the take-up drum 3 includes a spline-shaped recess for coupling with the coupling part 41, and the coupling part 41 is fitted into the recess.

The torsion bar 4A is configured to plastically deform when the pulling force of the webbing 10 exceeds a predetermined value in a state where the lock base 6 is prevented from rotating in the pulling direction, so as to absorb impact energy while allowing relative rotation between the take-up drum 3 and the lock base 6 .

The impact energy absorbing wire 4B is configured to absorb impact energy at an initial stage when the reel 3 and the locking base 6 rotate relative to each other. In the present embodiment, as illustrated in FIG8 , the reel 3 includes two grooves 35 opened in the first end surface 31. In the present embodiment, although each groove 35 has a groove shape obliquely recessed from the outer circumferential surface of the reel 3, the groove 35 may be a hole extending in the axial direction of the reel 3.

The impact energy absorbing wire 4B is accommodated in one of the grooves 35 in a state where the head 43 (see FIG. 6 ) protrudes from the opening 36 of the groove 35. The impact energy absorbing wire 4B is configured to plastically deform to absorb impact energy while being pulled out from the opening 36 in the case where the reel 3 and the lock base 6 rotate relative to each other. Incidentally, the impact energy absorbing wire 4B may be omitted.

The stopper member 4C defines the amount of relative rotation allowed between the take-up drum 3 and the lock base 6 when the torsion bar 4A absorbs impact energy. The stopper member 4C is held in the center hole 30 of the take-up drum 3 and is non-rotatable relative to the take-up drum 3 and is movable in the left-right direction.

6 , the stopper member 4C has a tubular shape through which the torsion bar 4A is inserted. The stopper member 4C has a female thread 47 formed on an inner circumferential surface thereof.

In the present embodiment, the stop member 4C includes an annular portion 45 and three claw portions 46 protruding from the annular portion 45 in the right direction. On the other hand, the center hole 30 of the take-up drum 3 includes three guide grooves 34. Since the corresponding three claw portions 46 are fitted in the three guide grooves 34, the stop member 4C is held by the take-up drum 3 and is non-rotatable relative to the take-up drum 3, and is movable in the left-right direction. However, instead of the stop member 4C including the claw portions 46, the cross-sectional shape of the outer shape of the stop member 4C and the cross-sectional shape of the left end portion of the center hole 30 of the take-up drum 3 may be a polygon.

As illustrated in FIGS. 3 and 7 , the locking base 6 is formed with a male thread 73 onto which the female thread 47 of the stop member 4C is screwed. The annular drive wheel 5 is attached to the locking base 6. In the present embodiment, as illustrated in FIG. 3 , during the relative rotation between the reel 3 and the locking base 6, the stop member 4C moves from a position where the stop member 4C is separated from the drive wheel 5 to a position where the stop member 4C is in contact with the drive wheel 5, whereby the relative rotation between the reel 3 and the locking base 6 is constrained to a predetermined amount. Accordingly, the stop member 4C is in contact with the drive wheel 5, easily preventing the stop member 4C from moving in the axial direction of the reel 3, and the relative rotation between the reel 3 and the locking base 6 can be constrained to a predetermined amount.

As shown in Figures 7 and 9, the drive wheel 5 includes: a main body 51 having an assembly hole with a hexagonal cross-sectional shape; a plurality of teeth 52 formed on the outer circumferential surface of the main body 51; an annular flange 53 protruding outwardly from the main body 51 in a radial direction on the right side of the teeth 52; and an annular rib 55 protruding from the flange 53 in a rightward direction.

The flange 53 includes a plurality of (six in the illustrated example) holding grooves 54. The head 43 of the impact energy absorbing wire 4B is attached to one of the holding grooves 54. The head 43 of the impact energy absorbing wire 4B includes a fall-off prevention portion 44 (see FIG. 6 ) having a greater width than the holding groove 54.

As illustrated in Fig. 3, in the present embodiment, the drive wheel 5 contacts the first end surface 31 of the take-up drum 3 via the rib 55. The impact energy absorbing wire 4B is wound on the rib 55 while being pulled out from the opening 36 of the groove 35. In a case where the take-up drum 3 and the locking base 6 rotate relative to each other, the drive wheel 5, which is attached to the locking base 6 and is non-rotatable relative to each other, rotates relative to the take-up drum 3, while the rib 55 of the drive wheel 5 contacts the first end surface 31 of the take-up drum 3 in the axial direction of the take-up drum 3, and while the outer peripheral edge of the flange 53 of the drive wheel 5 contacts the folded portion 3Ba of the bearing 3B attached to the take-up drum 3 in the radial direction of the take-up drum 3.

In addition, an annular flange 56 protrudes from the inner circumferential surface of the main body portion 51. The flange 56 is a portion that contacts the stopper member 4C. In this way, by making the stopper member 4C contact the flange 56 of the drive wheel 5 instead of contacting the step portion (the proximal end portion 72a described later) of the lock base 6, a large contact area between the flange 56 and the stopper member 4C can be ensured.

The pretensioner 1C rotates the reel 3 in the reeling direction via the drive wheel 5, the locking base 6 and the torsion bar 4A in an emergency situation of the vehicle. As illustrated in FIGS. 2 to 4 , the pretensioner 1C includes: a pretensioner housing 11 attached to the first side wall 21 of the housing 2; a tube 12 extending from the pretensioner housing 11 while being bent; a moving member 13 disposed in the tube 12; and a gas generator 18 disposed in the distal end of the tube 12.

In the present embodiment, the movable member 13 has a rod shape and is configured to be plastically deformed by digging into the teeth 52 of the drive wheel 5. However, the movable member 13 can be implemented by a plurality of segmented bodies (e.g., spheres) arranged at the same pitch as the teeth 52 of the drive wheel 5. In an emergency situation of the vehicle, the movable member 13 engages with the teeth 52 of the drive wheel 5 and is simultaneously pushed out of the tube 12 by the gas generated in the gas generator 18, and the movable member 13 causes the drive wheel 5 to rotate in the winding direction. When the drive wheel 5 rotates, the locking base 6, the torsion bar 4A and the winding drum 3 also rotate. After the pretensioner 1C is activated, the gas pressure in the tube 12 prevents the movable member 13 from being pushed back into the tube 12, thereby preventing the drive wheel 5 from rotating in the pulling direction.

As illustrated in Figures 2 and 5, the pretensioner housing 11 is provided with an opening 11a through which the locking base 6 is inserted, and the opening 11a has internal teeth 11b formed on the circumferential edge of the opening 11a. On the other hand, the locking base 6 includes a lock member 61 configured to be engageable with the internal teeth 11b. The lock member 61 engages with the internal teeth 11b in an emergency situation of the vehicle to prevent the locking base 6 from rotating in the pull-out direction.

10 to 14 , the locking base 6 includes a first base member 7 to which the drive wheel 5 is attached and a second base member 8, which is attached to the first base member 7 on a side of the first base member 7 opposite to the reel 3 and is non-rotatable relative to the first base member 7. A lock member 61 is held between the first base member 7 and the second base member 8.

More specifically, the first base member 7 includes a disc-shaped first main body portion 71 and a protrusion 72 protruding from the first main body portion 71 in the right direction. As illustrated in FIG. 3 , the drive wheel 5 is disposed between the first main body portion 71 and the first end surface 31 of the take-up drum 3, and the protrusion 72 penetrates the drive wheel 5. A male thread 73 is formed on the outer circumferential surface of the distal end side of the protrusion 72. The protrusion 72 includes a proximal portion 72a at the proximal side of the male thread 73, and the proximal portion 72a protrudes radially outward more than the male thread 73. The proximal portion 72a of the protrusion 72 is formed to have a hexagonal cross-sectional shape. The assembly hole of the main body portion 51 of the drive wheel 5 is also formed to have a hexagonal cross-sectional shape, and by fitting the proximal portion 72a into the assembly hole, the drive wheel 5 is attached to the first base member 7 and is non-rotatable relative to the first base member 7. However, the proximal portion 72a of the protrusion 72 may be formed to have a non-circular cross-sectional shape, such as a polygon other than a hexagon. The fitting hole of the main body 51 of the driving wheel 5 is also formed to have a non-circular cross-sectional shape, and by fitting the proximal end portion 72a into the fitting hole, the driving wheel 5 is attached to the first base member 7 and is non-rotatable relative to the first base member 7 .

The first base member 7 includes a first recess 74 recessed from the distal end surface of the protruding portion 72 and a second recess 75 coaxial with the first recess 74 and recessed from the surface of the first body portion 71 on the opposite side to the driving wheel 5. The first recess 74 is a spline-shaped recess for coupling with the coupling portion 42 of the torsion bar 4A, and the coupling portion 42 is fitted in the first recess 74. In the present embodiment, the second recess 75 has a circular cross-sectional shape.

In the present embodiment, the first base member 7 includes a partition 76 that separates the first recess 74 and the second recess 75. That is, the first recess 74 and the second recess 75 are at the bottom. Therefore, it is possible to avoid the first base member 7 having a shape of a deep recess or a thick portion. Accordingly, the first base member 7 can be formed by, for example, forging.

13, the second recess 75 has a depth overlapping the drive wheel 5 in the left-right direction, and there is a gap between the distal end of the fitting protrusion 82 (to be described later) of the second base member 8 and the partition 76 of the first base member 7. For example, the gap between the distal end of the fitting protrusion 82 of the second base member 8 and the partition 76 of the first base member 7 is 0.5 mm to 5.0 mm.

The second base member 8 includes a plate-like second main body portion 81, which overlaps with the first main body portion 71, and a fitting protrusion 82, which protrudes from the second main body portion 81 in the right direction. In the present embodiment, the second main body portion 81 includes three engaging concave portions 87, and the second base member 8 is attached to the first base member 7 and cannot rotate relative to the first base member 7 by engaging the three engaging convex portions 79 provided on the first main body portion 71 with the engaging concave portions 87, respectively. The fitting protrusion 82 has a circular cross-sectional shape, and the fitting protrusion 82 is fitted into the second recess 75. However, the second recess 75 and the fitting protrusion 82 may have a non-circular cross-sectional shape, and by fitting the fitting protrusion 82 into the second recess 75, the second base member 8 may be attached to the first base member 7 and cannot rotate relative to the first base member 7. In this case, the engaging concave portion 87 and the engaging convex portion 79 may be omitted.

In the present embodiment, the second main body portion 81 of the second base member 8 includes three crimping protrusions 85 protruding in the right direction, and the first main body portion 71 of the first base member 7 is provided with three through holes 77 into which the crimping protrusions 85 are inserted. As illustrated in FIG. 15 , a crimping concave portion 78 is formed on the side of the first main body portion 71 opposite to the second main body portion 81, and the crimping concave portion 78 is coaxial with the through hole 77 and has a larger diameter than the through hole 77. A portion of each crimping protrusion 85 protruding from the through hole 77 is crimped to have a larger diameter than the through hole 77 in the crimping concave portion 78, and has an outer diameter substantially equal to the inner diameter of the crimping concave portion 78 (in FIG. 10 to FIG. 12 , the crimping protrusion 85 is drawn as a shape before crimping). In addition, after crimping, the crimping protrusion 85 does not protrude from the crimping concave portion 78 to the drive wheel 5 side. The number of the crimping protrusions 85 and the number of the through holes 77 are not necessarily three, and may be one, two, or four or more.

In the present embodiment, as illustrated in FIG. 14 , in a state where the driving wheel 5 is attached to the locking base 6 , the crimping protrusions 85 after crimping are partially hidden by the teeth 52 of the driving wheel 5 .

The first base member 7 is formed of a material having higher strength than the second base member 8. For example, the first base member 7 is formed of carbon steel, and the second base member 8 is formed of an aluminum alloy or a zinc alloy. In the case where the second base member 8 does not have the crimping protrusion 85, the second base member 8 may be formed of a resin, and may be provided with a claw that engages with the crimping concave portion by utilizing elastic deformation of the resin instead of the crimping protrusion 85. When the second base member 8 is formed of an aluminum alloy or a zinc alloy having a low specific gravity or is formed of a resin, the second base member 8 can be reduced in weight.

The locking member 61 includes: a generally arcuate and plate-shaped main body portion 62, which is retained by a first main body portion 71 of a first base member 7 and a second main body portion 81 of a second base member 8; a plurality of (three in the illustrated example) engaging teeth 63, which are formed on the outer surface of the main body portion 62 and are configured to engage with the inner teeth 11b; and an operating shaft 64, which protrudes from the main body portion 62 in a leftward direction.

The second main body portion 81 of the second base member 8 includes a pin 84 protruding in the left direction. The return spring 9A has a substantially circular arc shape as illustrated in FIG. 7 . The return spring 9A includes one end engaged with the operating shaft 64 of the lock member 61 and the other end engaged with the pin 84. The return spring 9A is configured to hold the lock member 61 at the non-engaged position illustrated in FIG. 16A .

As illustrated in Figure 13, the second base member 8 is provided with an engagement hole 83 which is coaxial with the fitting protrusion 82 and opens in the left direction. In the present embodiment, the engagement hole 83 penetrates the second base member 8 and also opens in the right direction. The engagement hole 83 has a hexagonal cross-sectional shape.

The lock member 61 is operated by the synchronous gear 14 (see FIGS. 2 and 7 ). As illustrated in FIG. 2 , the locking unit 1D includes a cover member 17 that accommodates the synchronous gear 14 and a vehicle sensor 16. The synchronous gear 14 includes a belt sensor 15. The belt sensor 15 is configured to be activated when the belt 10 is pulled out quickly, thereby preventing the synchronous gear 14 from rotating in the pulling direction. The vehicle sensor 16 is configured to be activated when the acceleration of the vehicle changes greatly, thereby preventing the synchronous gear 14 from rotating in the pulling direction.

When the synchronous gear 14 is prevented from rotating in the pulling direction, the locking base 6 rotates together with the winding drum 3 relative to the synchronous gear 14, and the operating shaft 64 of the locking member 61 operates in the guide hole 14a (see Figure 7) of the synchronous gear 14, thereby moving the locking member 61 from the non-engaged position illustrated in Figure 16A to the engaged position illustrated in Figure 16B.

7 , the rotating shaft 9B includes a rod-shaped main body portion 91 and an arm 92 extending outward in the radial direction from the main body portion 91. The right side portion of the main body portion 91 has a hexagonal cross-sectional shape, and the right side portion is fitted into and engaged with the engagement hole 83 of the second base member 8. The arm 92 is used to constrain the return spring 9A, and a hook 93 provided at the distal end of the arm 92 is engaged with an engagement hole 86 provided in the second main body portion 81 of the second base member 8.

In the present embodiment, the rotation shaft 9B is formed of resin. As illustrated in FIG3 , the left side portion of the rotation shaft 9B penetrates the synchronizing gear 14 and is rotatably supported by the cover member 17 of the locking unit 1D.

As described above, in the seat belt retractor 1 according to the present embodiment, the locking base 6 is divided into the first base member 7 and the second base member 8, the male screw thread 73 is formed on the first base member 7, and thus the shapes of the first base member 7 and the second base member 8 can be simplified. Therefore, the locking base 6 can be easily manufactured.

In the present embodiment, a cavity is formed in the locking base 6 by a gap between the distal end of the fitting protrusion 82 of the second base member 8 and the partition 76 of the first base member 7, thereby reducing the volume of the first base member 7 and the volume of the second base member 8. Accordingly, the locking base 6 can be reduced in weight.

In the present embodiment, the rotating shaft 9B is formed of resin, and therefore the seat belt retractor 1 can be reduced in weight compared with the case where the rotating shaft 9B is formed of metal.

In the present embodiment, the crimping protrusion 85 of the second base member 8 inserted into the through hole 77 of the first base member 7 of the locking base 6 is crimped, and thereby the relative movement between the first base member 7 and the second base member 8 in the left-right direction (the axial direction of the take-up drum 3) can be easily prevented. In addition, the first base member 7 and the second base member 8 are integrated with each other after crimping, and thus assembly is also easy.

<Variation>

For the purpose of illustration and description, the foregoing description of exemplary embodiments of the present invention is provided. It is not intended to be exhaustive or to limit the present invention to the precise form disclosed. Obviously, many variations and changes are obvious to those skilled in the art. These embodiments are selected and described in order to best explain the principles of the present invention and its practical application, so that other technical personnel in the field can understand the present invention for various embodiments and various variations suitable for the specific purpose envisioned. It is intended that the scope of the present invention is limited by the appended claims and their equivalents.

For example, in the above-described embodiment, the pretensioner 1C is disposed outside the housing 2, however, the pretensioner 1C may be disposed inside the housing 2. In this case, the opening 21a of the first side wall 21 of the housing 2 includes inner teeth 11b formed on the circumferential edge of the opening 21a, and the lock member 61 may engage with the inner teeth 11b in an emergency situation of the vehicle.

A clutch may be provided between the driving wheel 5 and the locking base 6 so that the driving wheel 5 rotates in the winding direction of the belt together with the locking base 6 only in an emergency. In the case where the clutch is provided, for example, when the driving wheel 5 rotates in the winding direction by the moving member 13 and rotates a predetermined angle relative to the locking base 6, the driving wheel 5 and the locking base 6 are configured to be coupled to each other by the clutch so as to be able to rotate integrally.

The first base member 7 of the lock base 6 does not necessarily include the partition 76, and the first recess 74 and the second recess 75 may be continuous. In this case, the left end portion of the torsion bar 4A, instead of the rotation shaft 9B, may penetrate the lock base 6 and the synchronizing gear 14, and be rotatably supported by the cover member 17 of the lock unit 1D.

As shown in the first modification illustrated in Fig. 17, the first recess 74 and the second recess 75 may be continuous through a connecting hole 76a formed in the partition 76. In this case, by providing a convex portion 49 protruding through the connecting hole 76a into the second recess 75 at the left end portion of the torsion bar 4A and attaching a push nut 9C to the convex portion 49, the torsion bar 4A can be assembled to the first base member 7.

The rotation shaft 9B may be provided integrally with the second base member 8. In this case, the second base member 8 may be provided with a recessed portion recessed from a distal end surface of the fitting protrusion 82.

In the above-described embodiment, the rib 55 around which the impact energy absorbing wire 4B is wound is provided in the drive wheel 5, however, the rib 55 may be provided in the take-up drum 3. Alternatively, the rib 55 may be provided separately from the drive wheel 5, and the separation member may be attached to, for example, the protrusion 72 of the first base member 7 of the locking base 6 and may be non-rotatable relative to the protrusion 72. In this case, the separation member may be sandwiched between the drive wheel 5 and the first end surface 31 of the take-up drum 3.

As shown in the second modification illustrated in FIG. 18 , the proximal end portion 72a of the protrusion 72 in the first base member 7 may be extended to the right side (the distal end side where the male thread 73 is provided) instead of providing the annular flange 56 on the inner circumferential surface of the main body portion 51 of the driving wheel 5. In this case, the stop member 4C is configured to contact the proximal end portion 72a instead of the flange 56, and the stop member 4C moves to a position where the stop member 4C contacts the proximal end portion 72a. Therefore, during the relative rotation of the take-up drum 3 and the locking base 6, the stop member 4C moves from a position where the stop member 4C is separated from the proximal end portion 72a of the protrusion 72 to a position where the stop member 4C contacts the proximal end portion 72a, thereby restricting the relative rotation of the take-up drum 3 and the locking base 6 to a predetermined amount. As a result, the stopper member 4C contacts the proximal end portion 72a of the protrusion 72, easily preventing the stopper member 4C from moving in the axial direction of the take-up drum 3, and the relative rotation of the take-up drum 3 and the locking base 6 can be restricted to a predetermined amount. However, with respect to FIG. 18, the right end of the proximal end portion 72a of the protrusion 72 and the right edge of the fitting hole of the drive wheel 5 can be aligned, and the stopper member 4C can contact the proximal end portion 72a of the protrusion 72 and the drive wheel 5.

<Conclusion>

The seat belt retractor of claim 1, wherein the seat belt retractor comprises a housing, the housing comprising a first side wall and a second side wall facing each other; a reel configured to reel in a reel-shaped member, the reel-shaped member being accommodated between the first side wall and the second side wall so as to be rotatable in a reel-in direction and a reel-out direction of the reel-in. The reel-shaped member has a first end surface and a second end surface that is located on one side of the first side wall. The reel-shaped member is a bottom surface of the reel-shaped member, the bottom surface of the reel-shaped member being disposed adjacent to the bottom surface of the reel-shaped member. The locking member is connected to the locking base and cannot rotate relative to the locking base, the torsion bar is configured to plastically deform in a state where the locking base is prevented from rotating in the pulling direction and when the pulling force of the belt exceeds a predetermined value, and absorb impact energy while allowing relative rotation between the reel and the locking base; a pretensioner, the pretensioner comprising a pretensioner housing attached to the first side wall and a driving wheel attached to the locking base, the pretensioner being configured to rotate the reel in the winding direction via the driving wheel, the locking base and the torsion bar in an emergency situation of the vehicle; a locking member, the locking member being located in the locking base, the locking member being configured to engage with the first side wall or the pretensioner housing to prevent the locking base from rotating in the pulling direction in the emergency situation of the vehicle; and a stopping member, the stopping member being The locking member is configured to lock the locking cam and the locking cam in a manner that allows the locking cam to move relative to the first and second locking cams when the first and second locking cams are engaged. The extension socket structure of the second end face is connected with the upper edge of the extension socket to the upper edge of the extension socket to form a round shank, and the extension socket is connected with the upper edge of the extension socket to form a round shank.

According to the above configuration, the locking base is divided into the first base member and the second base member, on which the male thread is formed, and thus the shapes of the first base member and the second base member can be simplified. Therefore, the locking base can be easily manufactured.

As a second aspect according to the first aspect, the first base member can be formed of a material having a higher strength than the second base member. According to this configuration, the second base member can be formed of an aluminum alloy or a zinc alloy having a low specific gravity, or formed of a resin. Therefore, the second base member can be reduced in weight.

As a third aspect according to the first aspect or the second aspect, the first base member may include a partition that separates the first recess and the second recess. According to this configuration, the first recess and the second recess are at the bottom, and thus the first base member can be prevented from having a shape of a deep recess or a thick portion. Therefore, the first base member can be formed by, for example, forging.

As a fourth aspect according to the third aspect, the second recess may have a depth overlapping the driving wheel in the axial direction of the reel, and a gap may exist between the distal end of the assembly protrusion of the second base member and the partition of the first base member. According to this configuration, a cavity is formed in the locking base, and thus the volume of the first base member and the volume of the second base member can be reduced. Therefore, the locking base can be reduced in weight.

As a fifth aspect according to any one of the first to fourth aspects, the second base member may be provided with an engagement hole coaxial with the assembly protrusion and opening in a first direction opposite to the second direction, and the seat belt retractor may further include: a rotating shaft engaged with the engagement hole, the rotating shaft being formed of resin; and a cover member configured to rotatably support the rotating shaft. According to this configuration, the seat belt retractor can be reduced in weight compared to a case where the rotating shaft is formed of metal.

As a sixth aspect according to any one of the first to fifth aspects, the second main body portion may include at least one crimping protrusion, the at least one crimping protrusion protruding from the second main body portion along the second direction, the first main body portion may be provided with at least one through hole, the at least one crimping protrusion is inserted through the at least one through hole, and a portion of the crimping protrusion protruding from the through hole may be crimped to have a larger diameter than the through hole. According to this configuration, relative movement between the first base member and the second base member in the axial direction of the take-up drum can be easily prevented. In addition, the first base member and the second base member are integrated with each other after crimping, and thus assembly is also easy.

As a seventh aspect according to any one of the first to sixth aspects, the stop member can be prevented from moving in the axial direction of the take-up drum by contacting the drive wheel. According to this configuration, the stop member contacts the drive wheel, easily preventing the stop member from moving in the axial direction of the take-up drum, and the relative rotation between the take-up drum and the locking base can be restricted to a predetermined amount.

As an eighth aspect according to any one of the first to seventh aspects, the protrusion may include a proximal end portion protruding radially outward more than the male thread at the proximal side of the male thread, and the stop member may be prevented from moving in the axial direction of the reel by contacting the proximal end portion of the protrusion. According to this configuration, the stop member contacts the proximal end portion of the protrusion, easily preventing the stop member from moving in the axial direction of the reel, and the relative rotation between the reel and the locking base can be constrained to a predetermined amount.

Claims (8)

1. A seat belt retractor, comprising: a housing including a first side wall and a second side wall facing each other; a take-up drum configured to take up a belt-like object, the take-up drum being accommodated between the first side wall and the second side wall so as to be rotatable in a take-up direction and a pull-out direction of the belt-like object, the take-up drum having a central hole opened on a first end surface of the take-up drum, the first end surface of the take-up drum being located on one side of the first side wall; a locking base, the locking base being arranged to face the first end surface of the reel; a torsion bar inserted into the center hole of the take-up drum, the torsion bar including one end side and another end side, the one end side being opposite to the locking base, the one end side being coupled to the take-up drum and being non-rotatable relative to the take-up drum, the other end side being coupled to the locking base and being non-rotatable relative to the locking base, the torsion bar being configured to plastically deform in a state where the locking base is prevented from rotating in the pulling-out direction and when the pulling-out force of the webbing exceeds a predetermined value, so as to absorb impact energy while allowing relative rotation between the take-up drum and the locking base; a pretensioner including a pretensioner housing attached to the first side wall and a drive wheel attached to the locking base, the pretensioner being configured to rotate the reel drum in the reeling direction via the drive wheel, the locking base, and the torsion bar in an emergency situation of the vehicle; a lock member located in the locking base, the lock member being configured to engage with the first side wall or the pretensioner housing to prevent the locking base from rotating in the pulling direction in the emergency situation of the vehicle; and a stop member, the stop member being held in the central hole of the take-up drum and being non-rotatable relative to the take-up drum and being movable in the axial direction of the take-up drum, the stop member being screwed onto the male thread of the locking base, the stop member being configured to limit an allowable relative rotation amount between the take-up drum and the locking base when the torsion bar absorbs the impact energy, wherein the locking base comprises a first base member and a second base member, the drive wheel being attached to the first base member, the second base member being attached to the first base member on a side of the first base member opposite to the reel and being non-rotatable relative to the first base member, the second base member being configured to hold the lock member between the first base member and the second base member, The first base member comprises: a disc-shaped first body portion, wherein the drive wheel is disposed between the first body portion and the first end surface of the take-up drum; and a protrusion, the protrusion protruding from the first main body portion along a second direction of the axial direction of the take-up drum to penetrate the driving wheel, the second direction being a direction toward the second side wall, The male thread is formed on the outer circumferential surface of the distal end side of the protrusion, The first base member further comprises: a first recess recessed from a distal end surface of the protrusion, the first recess configured to be coupled to the torsion bar; and a second recessed portion, the second recessed portion being recessed from a surface of the first body portion on a side opposite to the driving wheel, the second recessed portion being coaxial with the first recessed portion, and The second base member comprises: a plate-shaped second main body portion, the second main body portion overlapping the first main body portion; and A fitting protrusion protrudes from the second body portion in the second direction, the fitting protrusion being fitted into the second recess. 2. The seat belt retractor according to claim 1, The first base member is formed of a material having a higher strength than the second base member. 3. The seat belt retractor according to claim 1 or 2, The first base member includes a partition portion separating the first recessed portion and the second recessed portion. 4. The seat belt retractor according to claim 3, wherein the second recess has a depth in the axial direction of the take-up drum that overlaps with the driving wheel, and There is a gap between the distal end of the fitting protrusion of the second base member and the partition portion of the first base member. 5. The seat belt retractor according to claim 1 or 2, wherein the second base member is provided with an engagement hole, the engagement hole being coaxial with the assembly protrusion and opening in a first direction opposite to the second direction, and The seat belt retractor also includes: a rotating shaft engaged with the engaging hole, the rotating shaft being formed of a resin; and A cover member is configured to rotatably support the rotating shaft. 6. The seat belt retractor according to claim 1 or 2, wherein the second main body portion comprises at least one crimping protrusion, and the at least one crimping protrusion protrudes from the second main body portion along the second direction, The first body portion is provided with at least one through hole, through which the at least one crimping protrusion is inserted, and A portion of the crimping protrusion protruding from the through hole is crimped to have a larger diameter than the through hole. 7. The seat belt retractor according to claim 1 or 2, The stop member is prevented from moving in the axial direction of the take-up drum by contacting the drive wheel. 8. The seat belt retractor according to claim 1 or 2, wherein the protrusion includes, at the proximal side of the male thread, a proximal portion protruding radially outward more than the male thread, and The stopper member is prevented from moving in the axial direction of the take-up drum by contacting the proximal end portion of the protrusion.