JP7369596B2 - Seatbelt retractor and seatbelt device - Google Patents

Description

The present invention relates to a seatbelt retractor and a seatbelt device, and particularly to a seatbelt retractor and a seatbelt device equipped with an energy absorption mechanism including a plurality of torsion bars.

2. Description of the Related Art Vehicles such as automobiles are generally provided with a seat belt device that restrains an occupant on a seat that includes a seat portion on which the occupant sits and a backrest portion located on the back of the occupant. Such a seatbelt device includes webbing for restraining an occupant, a seatbelt retractor for retracting the webbing, a buckle placed on the side of the seat, and a tongue placed on the webbing, and the tongue is fitted into the buckle. By doing so, the webbing restrains the occupant to the seat.

Here, it has become common for seatbelt retractors to include a pretensioner that removes slack in the webbing in an emergency such as a vehicle collision. Further, the seat belt retractor is often equipped with an energy absorption mechanism for reducing the load associated with forward movement of the occupant after the pretensioner is activated. Such an energy absorption mechanism can effectively reduce the load on the occupant by cooperating with other safety devices such as an airbag device.

For example, Patent Document 1 describes two torsion shafts (first load absorbing means and third load absorbing means) arranged in series along the axial direction of the spool, and two torsion shafts arranged so as to connect the spool and the lock base. A configuration is disclosed in which the amount of energy absorption is changed in stages using a wire (second load absorbing means).

JP2011-37411A

When a torsion bar is used as an energy absorbing member, the amount of energy absorbed depends on the amount of torsional deformation of the torsion bar, so the length and thickness of the torsion bar are important design factors. Therefore, when the torsion bars are arranged in series as in the invention described in Patent Document 1, the width of the seatbelt retractor increases when the torsion bars are lengthened, so the amount of energy absorption can be adjusted. The problem is that there are few.

In addition, in the invention described in Patent Document 1, members with different properties (torsion bar and wire) are used as energy absorbing members, so there is a problem that it is difficult to realize a desired load control pattern of the energy absorbing mechanism. There is.

The present invention was devised in view of such problems, and an object of the present invention is to provide a seatbelt retractor and a seatbelt device that can easily and arbitrarily set a load control pattern of an energy absorption mechanism.

According to the present invention, there is provided a spool for winding up webbing for restraining an occupant, a locking mechanism for regulating the rotation of the spool in the direction of pulling out the webbing in an emergency, and a locking mechanism for controlling the load applied to the webbing when the locking mechanism is activated. an energy absorption mechanism that absorbs the occupant's kinetic energy by restricting the kinetic energy of the occupant, the energy absorption mechanism being disposed on the central axis of the spool, and having a first end connected to the locking mechanism. a first torsion bar, which is fixed to the spool, and whose second end is configured to be able to engage with or disengage from the spool; a plurality of second torsion bars whose two ends are configured to be rotatable around the axis of the first torsion bar, the plurality of second torsion bars have a timing for starting torsional deformation or for ending torsional deformation; Provided is a seatbelt retractor characterized in that the seatbelt retractors are configured to have different timings.

The first torsion bar includes a center gear fixed to the second end side, each of the plurality of second torsion bars includes a round gear that can mesh with the center gear, and the center gear and the round The timing may be configured to vary by changing the meshing state with the gear.

Furthermore, at least one of the round gears may include a defective region where teeth are missing.

Further, at least one of the plurality of second torsion bars is configured to be movable in its own axial direction when rotating around the axis of the first torsion bar, and its axial movement causes the round gear to move. may be configured to mesh with the center gear.

Further, at least one of the plurality of second torsion bars is configured to be movable in its own axial direction when rotating around the axis of the first torsion bar, and its axial movement causes the round gear to move. may be configured to separate from the center gear.

Further, at least one of the plurality of second torsion bars may be configured such that the first end portion thereof is rotatable by a predetermined amount.

Further, according to the present invention, there is provided a seat belt device characterized by having a seat belt retractor having the above-described configuration.

According to the seatbelt retractor and seatbelt device according to the present invention described above, by configuring the timing at which the plurality of second torsion bars start torsional deformation or the timing at which the torsional deformation ends to be different from each other, for example, the energy The load control pattern of the absorption mechanism can be arbitrarily set such as "high load → medium load → low load" or "high load → low load → medium load". In addition, since it is only necessary that the plurality of second torsion bars start or end torsional deformation at different timings, the load control pattern of the energy absorption mechanism can be easily set.

FIG. 1 is an exploded view of parts showing a seatbelt retractor according to a first embodiment of the present invention. 2(A) is a perspective view, and FIG. 2(B) is a sectional view taken along line BB in FIG. 2(A). FIG. 3A is a partially enlarged view showing a state where the set load of the energy absorption mechanism is low; FIG. 3A is a perspective view, and FIG. 3B is a sectional view taken along line BB in FIG. 3A. It is a figure which shows an example of the load control pattern of an energy absorption mechanism, (A) has shown the first example, (B) has shown the second example. 2 is a partially enlarged view of the energy absorption mechanism shown in FIG. 1. FIG. 6 is a diagram showing the action of the energy absorption mechanism shown in FIG. 5, in which (A) shows an initial stage, (B) shows a medium load stage, and (C) shows a low load stage. It is a figure which shows the first modification of an energy absorption mechanism, (A) shows an initial stage, (B) shows a middle load stage, (C) shows a low load stage, and (D) shows a no-load stage. It is a figure which shows the second modification of an energy absorption mechanism, (A) has shown the initial stage, (B) has shown the load control pattern. FIG. 7 is a partially enlarged view showing an energy absorption mechanism of a seatbelt retractor according to a second embodiment of the present invention. 10 is a diagram showing the action of the energy absorption mechanism shown in FIG. 9, in which (A) shows an initial stage, (B) a medium load stage, and (C) a low load stage. It is a partial cross-sectional view which shows the energy absorption mechanism of the seatbelt retractor based on 3rd embodiment of this invention, (A) has shown the low load stage, (B) has shown the medium load stage. It is a partial cross-sectional view which shows the energy absorption mechanism of the seatbelt retractor based on the fourth embodiment of this invention, (A) shows an initial stage, (B) shows a low load stage, and (C) shows a middle load stage. There is. 1 is an overall configuration diagram showing a seat belt device according to an embodiment of the present invention.

Embodiments of the present invention will be described below using FIGS. 1 to 13. Here, FIG. 1 is a exploded view of parts showing a seatbelt retractor according to an embodiment of the present invention. FIG. 2 is a partially enlarged view showing a state where the set load of the energy absorption mechanism is high; (A) is a perspective view, and (B) is a sectional view taken along the line BB in FIG. 2(A). . FIG. 3 is a partially enlarged view showing a state in which the set load of the energy absorption mechanism is low; (A) is a perspective view, and (B) is a sectional view taken along the line BB in FIG. 3(A). .

As shown in FIG. 1, the seat belt retractor 1 according to the first embodiment of the present invention includes a spool 2 that winds up webbing for restraining an occupant, and a pretensioner that winds up the webbing to remove slack in an emergency. 3, a locking mechanism 4 that restricts the rotation of the spool 2 in the direction of pulling out the webbing in an emergency, and an energy absorption mechanism 5 that absorbs the kinetic energy of the occupant by limiting the load applied to the webbing when the locking mechanism 4 is activated. , is equipped with. Note that in FIG. 1, the illustration of the webbing is omitted.

The spool 2 is a winding drum that winds up the webbing, and is rotatably housed within a base frame 11 that forms the skeleton of the seat belt retractor 1. Further, for example, the pretensioner 3 and the lock mechanism 4 are arranged on the first end 21 side of the spool 2, and the energy absorption mechanism 5 and the spring unit 6 are arranged on the second end 22 side.

The pretensioner 3 includes a paddle gear 31 connected to the spool 2 and a power transmission device 32 that transmits power to the paddle gear 31 in an emergency. Note that the configuration of the pretensioner 3 is not limited to the illustrated configuration. The paddle gear 31 is fixed to an intermediate portion of a shaft portion 41 a of a locking base 41 , and the shaft portion 41 a of the locking base 41 is fixed to the spool 2 . Further, a bearing plate 23 may be arranged between the paddle gear 31 and the spool 2.

The power transmission device 32 includes, for example, a power transmission member (not shown) that transmits power to the paddle gear 31, a cylindrical guide member 33 that guides the power transmission member to the paddle gear 31, and a working gas inside the guide member 33. and a cover member 35 that forms a passage for a power transmission member around the outer periphery of the paddle gear 31.

In this embodiment, since the paddle gear 31 is arranged inside the base frame 11, the cover member 35 is arranged on the inner surface of the base frame 11, and the lock mechanism 4 is arranged on the outer surface of the base frame 11. A retainer cover 43 is arranged to accommodate the parts.

Note that when the paddle gear 31 is arranged outside the base frame 11, the cover member 35 is arranged on the outer surface of the base frame 11, and a part of the lock mechanism 4 is arranged outside the cover member 35. A retainer cover 43 for accommodating is arranged.

In an emergency such as a vehicle collision, working gas is supplied from the gas generator 34 into the guide member 33, and the power transmission member moves along the guide member 33. The power transmission member released from the guide member 33 collides with the engagement teeth of the paddle gear 31, causing the paddle gear 31 to rotate. The rotation of the paddle gear 31 rotates the spool 2 to wind up the webbing, removes slack in the webbing, and restrains the occupant to the seat.

The locking mechanism 4 includes, for example, a locking base 41 fixed to the spool 2, a lock gear 42 disposed adjacent to the locking base 41, and a retainer cover 43 that accommodates the lock gear 42. A vehicle sensor (not shown) may be disposed on the retainer cover 43 to detect sudden deceleration or inclination of the vehicle body. Note that the configuration of the lock mechanism 4 is not limited to the illustrated configuration.

The locking base 41 includes a shaft portion 41a fixed to the spool 2, and a flange portion 41b having a pawl (not shown) that can engage with internal teeth formed in the opening of the base frame 11. . An insertion hole 41c for fixing the first torsion bar is formed in the center of the shaft portion 41a. Further, the outer periphery of the shaft portion 41a is formed in a polygonal shape, and the paddle gear 31, the bearing plate 23, and the first end portion 21 of the spool 2 are inserted through and fixed to this portion.

A pawl is arranged on the flange portion 41b so as to be able to protrude and retract outward in the radial direction. The pawl is housed within the outer diameter of the flange portion 41b when the lock mechanism 4 is not in operation. Furthermore, when the lock mechanism 4 is activated, the pawl projects radially outward beyond the outer diameter of the flange portion 41b and engages with internal teeth formed in the opening of the base frame 11. By engaging the pawl with the base frame 11 in this manner, rotation of the locking base 41 in the webbing pulling direction can be restricted.

The lock gear 42 includes a swingable flywheel (not shown), and when the webbing is pulled out faster than the normal withdrawal speed, the flywheel swings and forms the webbing on the retainer cover 43. engages the internal teeth. Furthermore, when the vehicle sensor is activated, the lever of the vehicle sensor engages with external teeth formed on the side surface of the lock gear 42.

In this way, the rotation of the lock gear 42 is regulated by the operation of the flywheel or vehicle sensor. When the rotation of the lock gear 42 is restricted, relative rotation occurs between the locking base 41 and the lock gear 42, and the pawl moves radially outward from the flange portion 41b of the locking base 41 due to this relative rotation. stand out.

The energy absorption mechanism 5 is arranged, for example, on the central axis of the spool 2, a first end 51a is fixed to the lock mechanism 4, and a second end 51b is configured to be able to engage with or disengage from the spool 2. The first torsion bar 51 is arranged parallel to the first torsion bar 51, the first end 52a is fixed to the spool 2, and the second end 52b is configured to be rotatable around the axis of the first torsion bar 51. It includes a plurality of second torsion bars 52 and a switching mechanism 53 that switches the power transmission path from the spool 2 to the energy absorption mechanism 5.

The first torsion bar 51 is, for example, a rod-shaped metal member, and is an energy absorbing member that is plastically deformed by being twisted due to the rotation difference between the first end 51a and the second end 51b, and absorbs kinetic energy. . A cavity is formed in the center of the spool 2 into which the first torsion bar 51 is inserted. The first torsion bar 51 acts when the set load of the energy absorption mechanism 5 is high.

The first end 51a of the first torsion bar 51 is inserted into the insertion hole 41c of the locking base 41, and is fixed to the locking base 41 so as to be rotatable in synchronization with the locking base 41. The second end 51b of the first torsion bar 51 is pivotally supported by a spring core (not shown) of the spring unit 6, and is wound with webbing by a mainspring spring (not shown) built into the spring unit 6. It is biased in the direction of removal.

Further, a center gear 51c is fixed to the second end 51b side of the first torsion bar 51, and a bush 51d, a bearing 51e, and a push nut 51f are inserted between the center gear 51c and the spring core. You can leave it there. The center gear 51c is a component that transmits power between the first torsion bar 51 and the second torsion bar 52.

The second torsion bar 52 is, for example, a rod-shaped metal member, and is an energy absorbing member that is plastically deformed by being twisted due to the difference in rotation between the first end 52a and the second end 52b, and absorbs kinetic energy. . A cavity for inserting the second torsion bar 52 and a fixing hole 24 for fixing the second torsion bar 52 are formed in the outer circumference of the spool 2 . The second torsion bar 52 acts when the set load of the energy absorption mechanism 5 is medium load or low load. Therefore, the second torsion bar 52 usually has a shape that is thinner and shorter than the first torsion bar 51.

Further, a plurality of second torsion bars 52 are arranged along the outer periphery of the first torsion bar 51 at equal intervals. In this embodiment, since the two second torsion bars 52 are arranged, the two second torsion bars 52 are arranged at positions on both sides of the first torsion bar 51 (positions with a phase of 180°). be done. Note that the number of second torsion bars 52 is arbitrary and may be three or more.

The first end 52a of the second torsion bar 52 is inserted into the fixing hole 24 of the spool 2 and fixed to the spool 2 so as to be rotatable in synchronization with the spool 2. Further, the second end portion 52b of the second torsion bar 52 is rotatably supported by the link plate 54. The link plate 54 is a component that is fixed to the spool 2, allows insertion of the shaft portion on the second end 51b side of the first torsion bar 51, and rotatably supports the second end 52b of the second torsion bar 52. .

Specifically, the link plate 54 is, for example, a plate member having a substantially cross-shaped outer shape, and has a first opening 54a in the center through which the shaft on the second end 51b side of the first torsion bar 51 is inserted. A second opening 54b is formed on both sides of the first opening 54a, through which the second end 52b of the second torsion bar 52 is inserted.

Further, a recessed portion matching the outer shape of the link plate 54 is formed in the second end portion 22 of the spool 2 . By inserting the link plate 54 into this recess, the link plate 54 is fixed to the spool 2. At this time, the shaft portion of the first torsion bar 51 on the second end 51b side is inserted into the first opening 54a, and the second end 52b of the second torsion bar 52 is inserted into the second opening 54b.

Furthermore, a round gear 52c that rotates while meshing with the center gear 51c is fixed to the second end 52b side of the second torsion bar 52. The center gear 51c and the round gear 52c constitute a so-called planetary gear mechanism.

The switching mechanism 53 includes, for example, an engagement plate 53a connected to the first torsion bar 51, a release ring 53b configured to be able to be locked to the engagement plate 53a, and a ring holder 53c that slidably holds the release ring 53b. , and a power generating device 53d that slides the release ring 53b in the axial direction of the spool 2.

The engagement plate 53a is fixed to the shaft portion of the center gear 51c, and is fixed to the first torsion bar 51 via the center gear 51c. Further, on the outer edge of the engagement plate 53a, four concave portions 53e that are open outward are formed at equal intervals in the circumferential direction.

The release ring 53b includes an annular portion 53f having a large opening in the center, and a plurality of claws 53g extending from the inner edge of the annular portion 53f in a direction away from the spool 2. A planetary gear mechanism and a link plate 54 arranged at the second end 22 of the spool 2 are arranged inside the annular portion 53f. The claws 53g are arranged, for example, at four locations at equal intervals in the circumferential direction of the annular portion 53f, and are configured to be inserted into recesses 53e formed in the engagement plate 53a.

The ring holder 53c is a component that guides the movement of the spool 2 in the axial direction while suppressing interference between the release ring 53b and the planetary gear mechanism. The ring holder 53c has a substantially cap shape, and includes, for example, a cylindrical portion 53h that surrounds the outer periphery of the planetary gear mechanism, and an annular disk portion 53i that covers the outer periphery of the link plate 54.

An end of the cylindrical portion 53h opposite to the disk portion 53i is fixed to the second end 22 of the spool 2. A release ring 53b is slidably inserted into the outer peripheral surface of the cylindrical portion 53h. Moreover, a groove for guiding the claw 53g may be formed on the outer circumferential surface of the cylindrical portion 53h. Further, a plurality of protrusions for positioning the engagement plate 53a may be formed on the surface of the disc portion 53i.

The power generation device 53d includes, for example, a gas generator 53j that instantaneously generates working gas, a piston 53k driven by the working gas, a lever 53m driven by the piston 53k, and guides the movement of the piston 53k and the lever 53m. It includes a housing 53n that can hold the lever 53m, and a lever stopper 53p that holds the lever 53m at its initial position. The housing 53n includes a substantially cylindrical cylinder portion 53q and a body portion 53r formed to surround the outer periphery of the lever 53m.

A piston 53k is inserted into the cylinder part 53q, and a gas generator 53j is arranged at the rear end of the cylinder part 53q. A guide groove 53s for moving the lever 53m in a direction approaching the spool 2 while rotating the lever 53m is formed on the inner circumferential surface of the body portion 53r.

The lever 53m includes a ring portion 53t that can come into contact with the annular portion 53f of the release ring 53b, and a protrusion 53u that can come into contact with the piston 53k. A convex portion inserted into the guide groove 53s is formed on the outer peripheral surface of the ring portion 53t.

Here, the operation of the switching mechanism 53 will be explained with reference to FIGS. 2(A) to 3(B). In the initial state, the lever 53m is held at a position away from the spool 2 by the lever stopper 53p. At this time, as shown in FIGS. 2(A) and 2(B), the release ring 53b is also held at a position away from the spool 2, and the claw 53g is locked in the recess 53e of the engagement plate 53a. There is.

In this initial state, since the spool 2 and the first torsion bar 51 are connected, the power transmission path is as shown by the dotted line in FIG. 2(B): spool 2 → ring holder 53c → release The ring 53b → the engagement plate 53a → the bearing 51e → the center gear 51c → the first torsion bar 51 → the locking base 41 (fixed) → the base frame 11 (fixed). Therefore, since the limit load of the webbing is regulated by the first torsion bar 51, the set load of the energy absorption mechanism 5 is set to a high load.

When the gas generator 53j operates, the piston 53k moves along the cylinder portion 53q, and the tip of the piston 53k protrudes from the tip of the cylinder portion 53q. The piston 53k pushes away the protrusion 53u of the lever 53m, and the lever 53m moves in a direction approaching the spool 2 while rotating along the guide groove 53s.

Due to this axial movement of the lever 53m, the ring portion 53t comes into contact with the annular portion 53f of the release ring 53b, and the release ring 53b moves in a direction closer to the spool 2. This movement of the release ring 53b causes the claw 53g to disengage from the recess 53e of the engagement plate 53a, and the locked state of the release ring 53b is released, as shown in FIGS. 3(A) and 3(B).

In this final state, since the connection between the spool 2 and the first torsion bar 51 is released, the power transmission path is from the spool 2 to the second torsion bar 51 as shown by the dotted line in FIG. It is composed of bar 52 → round gear 52c → center gear 51c (fixed) → first torsion bar 51 (fixed) → locking base 41 (fixed) → base frame 11 (fixed). Therefore, since the limit load of the webbing is regulated by the second torsion bar 52, the set load of the energy absorption mechanism 5 is set to a medium load or a low load.

By the way, in the seat belt retractor 1 using the energy absorption mechanism 5 as described above, a high load defined by the torsional deformation of the first torsion bar 51 and a low load defined by the torsional deformation of the second torsion bar 52 can be handled. Generally, the load is controlled in two stages.

In contrast, the seatbelt retractor 1 according to the present embodiment attempts to control the load on the energy absorption mechanism 5 in multiple stages, as shown in FIGS. 4(A) and 4(B), for example. . Here, FIG. 4 is a diagram showing an example of a load control pattern of the energy absorption mechanism, in which (A) shows a first example and (B) shows a second example. In each of FIGS. 4(A) and 4(B), the horizontal axis represents time (s), and the vertical axis represents the load (N) applied to the occupant.

The load control pattern shown in FIG. 4A is such that the load applied to the occupant is changed from "high load α→medium load β→low load γ". When only the first torsion bar 51 is applied, the load is controlled to high α, and when the two second torsion bars 52 are applied, the load is controlled to medium β, and only one second torsion bar 52 is applied. When applied, the load is controlled to be low.

The load control pattern shown in FIG. 4(B) is such that the load applied to the occupant is changed from "high load α→low load γ→medium load β". In this case, as in the first example, when only the first torsion bar 51 is applied, the load is controlled to a high load α, and when the two second torsion bars 52 are applied, the load is controlled to a medium load β. , the load is controlled to be low when only one second torsion bar 52 is applied.

Hereinafter, the configuration of the energy absorption mechanism 5 that realizes the load control patterns of the first example and the second example will be described. Here, FIG. 5 is a partially enlarged view of the energy absorption mechanism shown in FIG. 1. FIG. 6 is a diagram showing the action of the energy absorption mechanism shown in FIG. 5, in which (A) shows the initial stage, (B) shows the middle load stage, and (C) shows the low load stage.

In the energy absorption mechanism 5 shown in FIG. 5, at least one of the round gears 52c disposed on the second torsion bar 52 is provided with a missing region 52d in which a tooth is missing. For example, as shown in FIG. 6A, the round gear 52c located above the center gear 51c has no missing teeth, and the round gear 52c located below the center gear 51c has a missing area 52d. It is assumed that the

For convenience of explanation, the round gear 52c located above the center gear 51c will be referred to as a first round gear 52c', and the round gear 52c located below the center gear 51c will be referred to as a second round gear 52c''. do.

In the second round gear 52c'', numbers 10 to 12 are numbered counterclockwise with the teeth on the right side of the figure meshing with the center gear 51c in the initial state shown in FIG. 6(A) as the first. The missing region 52d is formed by missing the tooth No. 1.The number tooth to be removed is arbitrary and can be designed according to the timing of switching from medium load to low load.

In the initial state shown in FIG. 6(A), the second round gear 52c'' is held in mesh with the center gear 51c.Now, the switching mechanism 53 of the energy absorption mechanism 5 is activated, and the second round gear 52c'' is engaged with the center gear 51c. Assume that the bar 52 is now rotatable around the axis of the first torsion bar 51.

At this time, since the center gear 51c is in a fixed state (non-rotating state), the first round gear 52c' and the second round gear 52c'' are rotated clockwise in the figure, as shown in FIG. 6(B). At this time, since the first round gear 52c' and the second round gear 52c'' are meshed with the center gear 51c, the two second torsion bars 52 act, and the energy absorption mechanism 5 is load controlled to medium load β.

Furthermore, when the first round gear 52c' and the second round gear 52c'' revolve while rotating clockwise in the figure, the defective area 52d of the second round gear 52c'' is located at the center, as shown in FIG. The gear 51c is reached, and the meshing between the second round gear 52c'' and the center gear 51c is released.At this time, since only the first round gear 52c' is meshed with the center gear 51c, one The two torsion bars 52 act to control the load on the energy absorption mechanism 5 to a low load γ.

In this way, by forming the missing region 52d in the second round gear 52c'', the timing at which the torsional deformation of the two second torsion bars 52 ends can be made different, and the energy absorption mechanism can be The load can be controlled to a low load γ. That is, in the first embodiment described above, the meshing state between the center gear 51c and the round gear 52c (the first round gear 52c' and the second round gear 52c'') is changed. As a result, the timing at which the torsional deformation of the second torsion bar 52 ends is made different.

Next, a modification of the energy absorption mechanism 5 having a second round gear 52c'' with a defective region 52d will be described. Here, FIG. 7 is a diagram showing a first modification of the energy absorption mechanism. A) shows an initial stage, (B) shows a medium load stage, (C) shows a low load stage, and (D) shows a no-load stage. Fig. 8 is a diagram showing a second modification of the energy absorption mechanism. (A) shows the initial stage, and (B) shows the load control pattern.

In the first modification shown in FIGS. 7(A) to 7(D), a missing region 52e is also formed in the first round gear 52c'. The defect area 52e of the first round gear 52c' shown in FIG. 7(A) is formed wider than the defect area 52d of the second round gear 52c''. If the tooth on the left side of the diagram, which is meshed with the center gear 51c in the initial state shown in (A), is numbered counterclockwise, the defect area is 52d is formed.

In the initial state shown in FIG. 7A, the first round gear 52c' and the second round gear 52c'' are held in mesh with the center gear 51c.Now, the switching mechanism 53 of the energy absorption mechanism 5 is Assume that the second torsion bar 52 is activated and becomes rotatable around the axis of the first torsion bar 51.

At this time, since the center gear 51c is in a fixed state (not rotating), the first round gear 52c' and the second round gear 52c'' are rotated clockwise in the figure, as shown in FIG. 7(B). At this time, since the first round gear 52c' and the second round gear 52c'' are meshed with the center gear 51c, the two second torsion bars 52 act, and the energy absorption mechanism 5 is load controlled to medium load β.

Furthermore, when the first round gear 52c' and the second round gear 52c'' revolve while rotating clockwise in the figure, the defective area 52e of the first round gear 52c' is located at the center, as shown in FIG. The gear 51c is reached, and the meshing between the first round gear 52c' and the center gear 51c is released.At this time, since only the second round gear 52c'' is meshed with the center gear 51c, one of the first round gears The two torsion bars 52 act to control the load on the energy absorption mechanism 5 to a low load γ.

Furthermore, when the second round gear 52c'' revolves while rotating clockwise in the figure, the missing area 52d of the second round gear 52c'' reaches the center gear 51c, as shown in FIG. The meshing between the second round gear 52c'' and the center gear 51c is released. At this time, since both the first round gear 52c' and the second round gear 52c'' are not meshed with the center gear 51c, the Since the two torsion bars 52 are not present, the energy absorption mechanism 5 is load-controlled to be unloaded (zero load state).

In this way, by forming the defective regions 52d and 52e in the first round gear 52c' and the second round gear 52c'', respectively, the timing at which the torsional deformation of the two second torsion bars 52 ends can be made different from each other. Therefore, the energy absorption mechanism 5 can be controlled to have a medium load β, a low load γ, and no load.

The second modified example shown in FIGS. 8(A) and 8(B) is one in which the missing area 52e of the first round gear 52c' shown in FIG. 7(A) is expanded and all teeth are missing. It is. In this case, as shown in FIG. 8(B), the load control pattern of the energy absorption mechanism 5 can be set to "high load α→low load γ→no load".

Furthermore, although not shown, by removing all the teeth of the first round gear 52c' and the second round gear 52c'', the load control pattern of the energy absorption mechanism 5 can be set to "high load → no load". . In this way, by designing the defective areas 52d and 52e formed in the first round gear 52c' and the second round gear 52c'' as necessary, it is possible to arbitrarily control the load at any timing.

Next, a seatbelt retractor 1 according to a second embodiment of the present invention will be described with reference to FIGS. 9 to 10(C). Here, FIG. 9 is a partially enlarged view showing the energy absorption mechanism of the seatbelt retractor according to the second embodiment of the present invention. FIG. 10 is a diagram showing the action of the energy absorption mechanism shown in FIG. 9, in which (A) shows the initial stage, (B) shows the middle load stage, and (C) shows the low load stage. In addition, about the same component as the seatbelt retractor 1 based on the first embodiment mentioned above, the same code|symbol is attached|subjected and the overlapping description is abbreviate|omitted.

The seat belt retractor 1 according to the second embodiment has a load control pattern of the energy absorption mechanism 5 set to "high load α → medium load β → low load γ" as shown in FIG. 4(A). be.

The energy absorption mechanism 5 in this embodiment is configured such that one of the two second torsion bars 52 is movable in its own axial direction when rotating around the axis of the first torsion bar 51. The round gear 52c is configured to separate from the center gear 51c by axial movement.

Specifically, a male threaded portion 52f is formed on the outer periphery of the second end 52b of one second torsion bar 52, and a female threaded portion 54c is formed on the inner periphery of the second opening 54b of the corresponding link plate 54. has been done. As shown in FIG. 10(A), in the initial state, the tip of the second end 52b of the second torsion bar 52 is inserted into the second opening 54b of the link plate 54. At this time, the center gear 51c and the round gear 52c are in a meshed state.

Then, as the second torsion bar 52 rotates around the axis of the first torsion bar 51, the male threaded portion 52f rotates along the female threaded portion 54c, and as shown in FIG. The torsion bar 52 moves to the left in the figure. At this time, since the two second torsion bars 52 are acting, the load on the energy absorption mechanism 5 is controlled to a medium load β.

Furthermore, when the second torsion bar 52 rotates around the axis of the first torsion bar 51, the second torsion bar 52 moves to the left in the figure, and finally, as shown in FIG. Gear 52c will be completely separated from center gear 51c. At this time, since only one second torsion bar 52 is acting, the load on the energy absorption mechanism 5 is controlled to a low load γ.

Although not shown, male threaded portions 52f are formed on the two second torsion bars 52, female threaded portions 54c are formed on the corresponding link plates 54, and the timing at which the round gear 52c separates from the center gear 51c is made different. You can do it like this. With this configuration, the load control pattern of the energy absorption mechanism 5 can be set as "high load α→medium load β→low load γ→no load".

Next, a seatbelt retractor 1 according to a third embodiment of the present invention will be described with reference to FIGS. 11(A) and 11(B). Here, FIG. 11 is a partial sectional view showing the energy absorption mechanism of the seat belt retractor according to the third embodiment of the present invention, in which (A) shows a low load stage and (B) shows a medium load stage. There is. In addition, about the same component as the seatbelt retractor 1 based on the first embodiment mentioned above, the same code|symbol is attached|subjected and the overlapping description is abbreviate|omitted.

The seat belt retractor 1 according to the third embodiment changes the load control pattern of the energy absorption mechanism 5 from "high load α → low load γ → medium load β" as shown in FIG. 4(B). This is the setting.

The energy absorption mechanism 5 in this embodiment is configured such that one of the two second torsion bars 52 is movable in its own axial direction when rotating around the axis of the first torsion bar 51. The round gear 52c is configured to mesh with the center gear 51c by axial movement.

Specifically, a male threaded portion 52g is formed on the outer periphery of the first end 52a of one second torsion bar 52, and a female threaded portion 24a is formed on the inner periphery of the corresponding fixing hole 24. In the initial state, the tip of the first end 52a of the second torsion bar 52 is inserted into the fixing hole 24, and the round gear 52c is engaged with the center gear 51c.

Then, as the second torsion bar 52 rotates around the axis of the first torsion bar 51, the male threaded portion 52g rotates along the female threaded portion 24a, and as shown in FIG. The torsion bar 52 moves to the right in the figure. At this time, the round gear 52c starts to mesh with the center gear 51c, but since the first end 52a of the second torsion bar 52 is rotatable in the fixing hole 24, that is, it is not fixed. , the second torsion bar 52 is in a state where no twisting deformation occurs. Therefore, the energy absorption mechanism 5 is load-controlled to a low load γ.

Furthermore, when the second torsion bar 52 rotates around the axis of the first torsion bar 51, the second torsion bar 52 moves to the right in the figure, and finally, as shown in FIG. The first end 52a of the two torsion bar 52 reaches the bottom of the fixing hole 24, and movement to the right is restricted. At this time, the first end 52a of the second torsion bar 52 is fixed in the fixing hole 24, and the second torsion bar 52 starts torsionally deform. Therefore, the energy absorption mechanism 5 is load-controlled to a medium load β.

Although not shown, male threaded portions 52g are formed in the two second torsion bars 52, female threaded portions 24a are formed in the corresponding fixing holes 24, and the round gear 52c meshes with the center gear 51c to prevent torsional deformation. The starting timing may be different. With this configuration, the load control pattern of the energy absorption mechanism 5 can be set as "high load α→no load→low load γ→medium load β".

Next, a seatbelt retractor 1 according to a fourth embodiment of the present invention will be described with reference to FIGS. 12(A) to 12(C). Here, FIG. 12 is a partial sectional view showing the energy absorption mechanism of the seatbelt retractor according to the fourth embodiment of the present invention, in which (A) is an initial stage, (B) is a low load stage, and (C) is a The medium load stage is shown. In addition, about the same component as the seatbelt retractor 1 based on the first embodiment mentioned above, the same code|symbol is attached|subjected and the overlapping description is abbreviate|omitted. Further, the cross-sectional views shown in each figure illustrate a state in which a portion of the spool 2 including the fixing hole 24 is cut along a plane perpendicular to the axial direction.

The seat belt retractor 1 according to the fourth embodiment changes the load control pattern of the energy absorption mechanism 5 from "high load α → low load γ → medium load β" as shown in FIG. 4(B). This is the setting.

The energy absorption mechanism 5 in this embodiment is configured such that one first end 52a of the two second torsion bars 52 can rotate by a predetermined amount. Specifically, a projection 52h is formed on the outer periphery of the first end 52a of one second torsion bar 52, and a stopper 24b is formed on the inner periphery of the corresponding fixing hole 24. Note that a shaft portion (not shown) rotatably supported at the bottom of the fixing hole 24 may be formed at the tip of the first end portion 52a.

As shown in FIG. 12(A), in the initial state, the protrusion 52h of the second torsion bar 52 is rotatably disposed within the fixing hole 24. That is, the protrusion 52h and the stopper 24b are spaced apart from each other in the rotational direction of the protrusion 52h.

Then, as the second torsion bar 52 rotates around the axis of the first torsion bar 51, the protrusion 52h rotates so as to approach the stopper 24b, as shown in FIG. 12(B). At this time, since the first end 52a of the second torsion bar 52 is rotatable in the fixing hole 24, that is, it is not fixed, the second torsion bar 52 is in a state where no twisting deformation occurs. . Therefore, the energy absorption mechanism 5 is load-controlled to a low load γ.

In addition, in FIG. 12(B), although the spool 2 is actually rotating, for convenience of explanation, the fixing hole 24 having the stopper 24b is shown in the upper position. Similarly, in FIG. 12C, for convenience of explanation, the fixing hole 24 having the stopper 24b is shown in the upper position.

Further, when the second torsion bar 52 rotates around the axis of the first torsion bar 51, the protrusion 52h reaches the stopper 24b, as shown in FIG. 12(C), and the rotation of the second torsion bar 52 is restricted. be done. At this time, the first end 52a of the second torsion bar 52 is fixed in the fixing hole 24, and the second torsion bar 52 starts torsionally deform. Therefore, the energy absorption mechanism 5 is load-controlled to a medium load β.

Furthermore, although not shown, protrusions 52h are formed on the two second torsion bars 52, stoppers 24b are formed in the corresponding fixing holes 24, and the timings at which the second torsion bars 52 start twisting deformation are made different from each other. You can do it like this. With this configuration, the load control pattern of the energy absorption mechanism 5 can be set as "high load α→no load→low load γ→medium load β".

Next, a seat belt device according to an embodiment of the present invention will be described with reference to FIG. 13. Here, FIG. 13 is an overall configuration diagram showing a seat belt device according to an embodiment of the present invention. In addition, in FIG. 13, for convenience of explanation, components other than the seat belt device are illustrated with dashed lines.

A seat belt device 100 according to the present embodiment shown in FIG. 13 includes a webbing W for restraining an occupant, a seat belt retractor 1 for retracting the webbing W, and a guide anchor 101 provided on the vehicle body side for guiding the webbing W. The seatbelt retractor 1 includes, for example, a belt anchor 102 for fixing the webbing W to the vehicle body side, a buckle 103 disposed on the side surface of the seat S, and a tongue 104 disposed on the webbing W. It has the configuration shown in .

Components other than the seat belt retractor 1 will be briefly described below. The seat S includes, for example, a seat portion S1 on which an occupant sits, a backrest portion S2 located on the back of the occupant, and a headrest portion S3 that supports the occupant's head. The seat belt retractor 1 is often built into, for example, a B-pillar R of a vehicle body. Further, in general, the buckle 103 is often arranged on the side surface of the seat portion S1, and the belt anchor 102 is often arranged on the lower surface of the seat portion S1. Further, the guide anchor 101 is often arranged at the B pillar R. The webbing W has one end connected to the belt anchor 102 and the other end connected to the seat belt retractor 1 via the guide anchor 101.

Therefore, when the tongue 104 is fitted into the buckle 103, the webbing W is pulled out from the seat belt retractor 1 while sliding through the insertion hole of the guide anchor 101. Furthermore, when the occupant wears a seatbelt or releases the seatbelt when getting out of the vehicle, the webbing W is wound up by the action of the spring unit 6 of the seatbelt retractor 1 until a certain load is applied.

The seat belt device 100 described above is an ordinary seat belt device for a front seat to which the seat belt retractor 1 according to the first to fourth embodiments described above is applied. Therefore, according to the seat belt device 100 according to the present embodiment, by configuring the timing at which the second torsion bar 52 starts torsional deformation or the timing at which the torsional deformation ends to be different from each other, for example, the energy absorption mechanism 5 The load control pattern can be easily and arbitrarily set such as "high load → medium load → low load" or "high load → low load → medium load".

Note that the seat belt device 100 according to this embodiment is not limited to application to front seats, and can be easily applied to rear seats by omitting the guide anchor 101, for example. Furthermore, the seat belt device 100 according to this embodiment can be used in vehicles other than vehicles.

It goes without saying that the present invention is not limited to the embodiments described above, and that various changes can be made without departing from the spirit of the present invention.

1 Seatbelt retractor 2 Spool 3 Pretensioner 4 Lock mechanism 5 Energy absorption mechanism 6 Spring unit 11 Base frame 21 First end 22 Second end 23 Bearing plate 24 Fixing hole 24a Female thread 24b Stopper 31 Paddle gear 32 Power transmission device 33 Guide member 34 Gas generator 35 Cover member 41 Locking base 41a Shaft 41b Flange 41c Insertion hole 42 Lock gear 43 Retainer cover 51 First torsion bar 51a First end 51b Second end 51c Center gear 51d Bush 51e Bearing 51f Push nut 52 Second torsion bar 52a First end 52b Second end 52c Round gear 52c' First round gear 52c'' Second round gear 52d, 52e Missing areas 52f, 52g Male thread 52h Projection 53 Switching mechanism 53a Engagement plate 53b Release ring 53c Ring holder 53d Power generator 53e Concave portion 53f Annular portion 53g Claw 53h Cylindrical portion 53i Disc portion 53j Gas generator 53k Piston 53m Lever 53n Housing 53p Lever stopper 53q Cylinder portion 53r Body portion 53s Guide groove 53t Ring portion 53u Projection portion 54 Link plate 54a First opening portion 54b Second opening portion 54c Female screw portion 100 Seatbelt device 101 Guide anchor 102 Belt anchor 103 Buckle 104 Tong

Claims (7)

a spool for winding up webbing for restraining an occupant; a locking mechanism for restricting the rotation of the spool in the webbing pulling direction in an emergency; and a locking mechanism for restricting the load applied to the webbing when the locking mechanism is activated. A seatbelt retractor comprising: an energy absorption mechanism that absorbs kinetic energy of the seatbelt retractor;
The energy absorption mechanism is
a first torsion bar disposed on the central axis of the spool, a first end fixed to the locking mechanism, and a second end configured to be able to engage with or disengage from the spool;
a plurality of second torsion bars that are arranged parallel to the first torsion bar, have first ends fixed to the spool, and second ends configured to be rotatable around the axis of the first torsion bars; Equipped with
The plurality of second torsion bars are configured such that the timing at which they start torsional deformation or the timing at which they end torsional deformation are different from each other.
A seat belt retractor characterized by: The first torsion bar includes a center gear fixed to the second end side, each of the plurality of second torsion bars includes a round gear that can mesh with the center gear, and the center gear and the round The seat belt retractor according to claim 1, wherein the timing is configured to vary by changing the meshing state with a gear. 3. The seat belt retractor according to claim 2, wherein at least one of the round gears includes a defective region in which teeth are missing. At least one of the plurality of second torsion bars is configured to be movable in its own axial direction when rotating around the axis of the first torsion bar, and its axial movement causes the round gear to move in the direction of its axis. The seat belt retractor according to claim 2, wherein the seat belt retractor is configured to mesh with a center gear. At least one of the plurality of second torsion bars is configured to be movable in its own axial direction when rotating around the axis of the first torsion bar, and its axial movement causes the round gear to move in the direction of its axis. The seat belt retractor according to claim 2, wherein the seat belt retractor is configured to separate from the center gear. The seat belt retractor according to claim 2, wherein the first end of at least one of the plurality of second torsion bars is configured to be rotatable by a predetermined amount. A seat belt device comprising the seat belt retractor according to any one of claims 1 to 6.