JP4526149B2 - Seat belt device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a seat belt device that restrains an occupant of a vehicle or the like to a seat by webbing to ensure safety in the event of a collision, and more particularly to an improvement of a retractor having a function of forcibly winding a webbing in an emergency.
[0002]
[Prior art]
A seat belt device is used in vehicles and the like in order to ensure the safety of passengers. The seat belt device includes, for example, a retractor that includes a lock mechanism that rewinds the pulled webbing (belt) and prevents the webbing from being pulled out (can be wound) in an emergency. In addition to this retractor, there is also a combination of a pretensioner and a torsion shaft. The pretensioner forcibly winds the webbing on a reel in the event of a collision to remove the slack of the webbing. The torsion shaft is used as the rotation shaft of the reel. When a force exceeding a predetermined value is applied to the webbing due to the forward movement of the occupant after the collision, one end side is locked by a lock mechanism, and the other end side is coupled to the reel by a plastic (twist) deformation to rotate the reel. The webbing can be pulled out and the force applied to the occupant is suppressed. A device for preventing the pretensioner mechanism from hindering the twisting operation of the rotating shaft has been proposed. For example, Japanese Patent Laid-Open No. 10-226313 describes such an example. In this example, when the webbing is finished winding by the operation of the pretensioner, and then the webbing is pulled out, the clutch that transmits the winding force of the pretensioner to the reel rotation shaft is partially broken, and the reel rotation is not hindered. I am doing so.
[0003]
[Problems to be solved by the invention]
However, when a mechanism that breaks the member and makes the rotation axis (twisting shaft) of the reel free is used, it is necessary to form the member in a special shape in consideration of breaking the member. Inevitable.
[0004]
Therefore, an object of the present invention is to propose a seat belt device provided with a pretensioner mechanism that avoids the complication of members and does not hinder the twisting operation of the rotating shaft.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a seat belt device of the present invention includes a movable body that is movably disposed in a pipe, and a gas generator that is attached to the pipe and generates a high pressure that pushes the movable body in one direction. And a case that fixes the pipe, and is arranged coaxially with the retractor shaft, and when the outer periphery rotates in one direction, one end is wound around the outer periphery of the clutch coupled to the retractor shaft and the clutch part, The other end side of the wire is locked in the housing formed in the case via the moving body, and the wire moves when the moving body moves in the other direction from the initial arrangement position. Is released.
[0006]
By adopting such a configuration, one end of the wire is detached when the moving body enters the pipe from the initial position, so that it is possible to obtain a structure in which the wire does not hinder the rotation of the retractor shaft without breaking the member. .
[0007]
The function of the torsion shaft can be ensured by using the retractor shaft as a torsion shaft that plastically deforms and absorbs an impact when it receives a force exceeding a certain value.
[0008]
Preferably, caulking balls are formed on the other end side of the wire , and the diameter is partially increased. The storage portion is a caulking ball storage space, and the caulking ball is locked in a U-shaped groove in the caulking ball storage portion. The storage space is provided near the outlet of the pipe. The moving body functions as a door that restricts the wire movement (or caulking ball movement) to the outside of the caulking ball storage portion at the initial position, and opens the other end of the wire (or caulking ball) at a position lower than the initial position. . The moving body is, for example, a rod or a rolling element, and when the moving body enters the pipe from the initial position, the end of the wire is detached and the rotation of the twisted shaft is not hindered.
[0009]
Preferably, a shear pin is disposed in the vicinity of the outlet of the storage unit or the caulking ball to stabilize the caulking ball position.
[0010]
Preferably, a caulking ball storage space is provided along the movement path of the rod.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, corresponding parts are denoted by the same reference numerals, and redundant description is omitted.
[0012]
FIG. 1 is an explanatory view showing a retractor for a seat belt apparatus provided with a pretensioner as viewed from the side surface in the axial direction, and is a partial cross-sectional view in the BB direction (pretensioner part) shown in FIG. Show. 2 is a cross-sectional view of the retractor shown in FIG. 1 in the AA direction (pretensioner portion). FIG. 3 is an explanatory diagram illustrating the configuration of the clutch unit. 4 and 5 are explanatory diagrams for explaining the operation of the clutch.
As shown in FIGS. 1 and 2, the retractor 10 of the seat belt apparatus includes a retractor body 13 that winds up webbing (not shown), an emergency lock mechanism 14 provided on the right end side of the retractor body 13, and A pretensioner 12 and a winding spring device 11 provided on the left end side are provided.
[0013]
The retractor body 13 includes a take-up reel 22 that can freely wind or pull out the webbing. The reel 22 is connected to a retractor shaft 24, which is a winding shaft, via a sleeve 44a described later. The reel 22 is always urged in the direction in which the webbing is taken up by the take-up spring device 11 connected to the left end side of the retractor shaft 24. The emergency lock mechanism 14 provided on the right end side of the retractor shaft 24 operates when the acceleration sensor detects a deceleration exceeding a predetermined value, or when the webbing is pulled out with an acceleration exceeding the predetermined value. Prevents rotation in the belt withdrawal direction. Accordingly, the webbing is prevented from being pulled out from the reel 22, and the occupant is prevented from moving forward.
[0014]
The lock mechanism 14 allows the retractor shaft 24 to rotate in the webbing winding direction even in the locked state, and enables the webbing winding (slack removal) by the pretensioner 12 in the event of a collision.
[0015]
A portion of the retractor shaft 24 housed in the take-up reel 22 is a twisted shaft 24a. An example of using a torsion shaft (torsion bar) for a retractor is disclosed in, for example, Japanese Patent Laid-Open No. 46-7710. If an excessive pulling force is applied to the webbing after the emergency lock mechanism 14 is activated, a rotational force is applied to the reel 22. The torsion shaft 24a, whose right end side is locked and whose left end side is coupled to the reel through the sleeve so as not to be relatively rotatable, is twisted and plastically deformed, thereby enabling the webbing to be drawn.
[0016]
The pretensioner 12 includes an L-shaped pipe 70 constituted by a cylindrical portion 72 and a square tubular portion 74, a gas generator 32, an extrusion member, a rod, a wire, a clutch mechanism, and the like. The L-shaped pipe 70 is formed by connecting a cylindrical portion 72 and a square tubular portion 74 via a constricted portion 76. The constricted portion 76 is deeply constricted on the upper side and has a gently tapered portion on the lower side. The gas generator 32 is fitted into the opening of the cylindrical portion 72 and attached by caulking the opening. The gas generator 32 includes an electrode, an ignition device, and a high-pressure gas generating agent (not shown). An ignition signal transmission harness that transmits a signal from a shock sensor (not shown) that detects a rapid acceleration generated at the time of a vehicle collision is connected to the electrode. When an ignition signal is transmitted from the shock sensor to the electrode, the ignition device ignites the high-pressure gas generating agent to instantly generate high-pressure gas. The gas generator 32 may be attached by screwing or a cap.
[0017]
The pushing member 42 and the rod 36 as a moving body are accommodated and disposed at a predetermined position inside the rectangular tube portion 74. The push-out member 42 is a heat-resistant elastic body having a sealing function (gas leakage prevention) as shown in FIG. 14, and moves in the rectangular tube portion 74 by the pressure of the generated gas to push the rear end of the rod 36. increase.
[0018]
The push-out member 42 can be constituted by, for example, a square piston 42b and a seal member 42c corresponding to the cylinder 74 having a square cross section. A hole 42a is formed in the center of the piston 42b. The sealing member 42c is made of plastic such as rubber or resin. The piston 42b is selected to be harder (rigid body) than the sealing member 42c such as iron or hard plastic.
[0019]
The initial position (arrangement position) of the rod 36 and the pushing member 42 is caused by friction between the pushing member 42 and the inner wall of the rectangular tube portion 74, or by a plurality of small protrusions 70a on the inner wall of the rectangular tube portion 74 as shown in FIG. Retained.
[0020]
In the example shown in FIG. 12, the pushing member 42 has a cylindrical hole 42 a in the central axis direction of the rectangular tube portion 74. The hollow portion 42a and the cylindrical gas vent hole 36b formed in the rod 36 are communicated with each other by a narrow tube 36a (see FIGS. 15 and 16) formed in the bottom portion of the rod 36. The narrow tube 36a is relatively difficult to pass through rapid expansion gas, but when the rod 36 descends, it functions as a gas vent (pressure release) hole for the gas in the pipe, facilitating the return of the rod 36. . The thin tube 36a is formed with an inner diameter of 1 mm and a length of about 5 to 8 mm, for example.
[0021]
The tip of the rod 36 has a semi-cylindrical shape and is slidably in contact with the wire 40. A caulking ball 46 is attached to one end of the wire 40, and the other end is wound around a pulley 44c of the clutch mechanism 44, and is fixed to the pulley 44c by hooking, welding, screwing or the like. The caulking ball 46 is housed and disposed in a space (caulking ball housing space) 26 a defined by the stopper portion 26 b of the case 26, the lower case portion 26 d, the rectangular tube portion 74, and the rod 36. In an initial state before the pretensioner is actuated, the communication port (exit) 26e between the caulking ball storage space 26a and the internal space of the case 26 is closed by the rod 36, and the caulking ball 46 abuts against the stopper portion 26b and is locked. Has been.
[0022]
FIG. 7 is a cross-sectional view of the upper side in the CC direction of FIG. 2. The caulking ball 46 passes the wire 40 through a “U” -shaped groove formed in the wall of the stopper portion 26 b, and caulking ball 46. The end of 46 is locked against the wall of the stopper 26b. By using such a “U” -shaped groove that is partially open to the inner space side of the case 26, the caulking ball 46 is easily detached.
[0023]
Inside the case 26, a guide surface 26c for guiding the movement of the rod 36 is formed so as to be flush with the inner wall of the rectangular tube portion 74 in the extending direction of the inner wall of the rectangular tube portion 74.
[0024]
The clutch mechanism 44 is configured as shown in FIG. 3, for example, and includes a sleeve 44a, a plate 44b, and a pulley 44c arranged concentrically. A plurality of protrusions (claws) 44bb bent in the axial direction are formed on the plate 44b.
[0025]
As shown in FIGS. 1 and 2, the sleeve 44 a is attached to the left end side of the retractor shaft 24 and is connected to the reel 22 so as not to rotate relative thereto. On the surface of the sleeve 44a facing the pulley 44c, a large number of groove ridges (knurls) 44aa that circulate around the shaft (retractor shaft 24) are formed in the axial direction, and a meshing force is generated when the projections 44bb of the plate 44b come into contact.
[0026]
The pulley 44c has a wire 40 attached to its outer peripheral surface and a cam surface formed on its inner peripheral surface. This cam surface is opposed to the groove portion of the sleeve 44a through the protrusion 44bb of the plate 44b. The pulley 44c is held by the case 26 when the shear pin 26ca is fitted into the hole 44ca.
[0027]
4 and 5 are explanatory diagrams for explaining the operation of the clutch device 44. In the initial state shown in FIG. 4, when the rod 36 moves and pushes up the wire 40, the pulley 44c rotates counterclockwise. Thereby, the shear pin 26ca holding the pulley 44c is folded. At this time, the plate 44b cannot follow the rotation of the pulley 44c due to its own inertia, and a rotational phase difference is generated between the pulley 44c and the plate 44h. For this reason, the projection 44bb is bent toward the axial center by the cam surface of the pulley 44c and abuts against the groove 44aa of the sleeve 44a. Then, as shown in FIG. 5, the projection 44bb of the plate 44b is interposed between the inner surface of the pulley 44c and the groove 44 of the sleeve 44a, and the clutch is engaged. The rotation of the pulley 44c is transmitted to the retractor shaft 24 through the protrusion 44bb and the sleeve 44a. Thereby, the reel 22 rotates and the webbing can be taken up.
[0028]
The outer diameter of the pulley 44 c of the clutch 44 is smaller than the outer diameter of the reel 22. A wire 40 is wound almost twice around the pulley 44c, and the wire and the pulley 22 constitute a speed increasing mechanism based on a so-called “slip method”.
[0029]
Next, the operation of this embodiment will be described. First, in an initial state in which an occupant gets on a vehicle, sits down, and wears a webbing, the pretensioner 12 is in an initial state shown in FIGS. In this initial state, as shown in both figures, since the projection 44bb of the plate 44b and the sleeve 44a are separated from each other, the clutch device 44 does not participate in the pretensioner 12 at all (non-coupled state), and the retractor shaft. 24 is rotatable in the webbing pull-out direction.
[0030]
In this initial state, it is assumed that a sudden speed reduction occurs at the time of a collision in the vehicle. As a result, the lock mechanism 14 is activated to prevent the retractor shaft 24 from rotating in the webbing pull-out direction. Further, the gas generator 32 instantaneously generates a pressurized gas, and this pressurized gas is released into the pressure chamber (in the cylindrical portion 72). As a result, a sudden pressing force is applied to the pushing member 42 from below, and the entire rod 36 housed in the rectangular tube portion 74 is pushed out instantaneously upward.
[0031]
This pushing force is superior to the force of the wire 40 pressing the tip of the rod 36 in the initial state. As shown in FIGS. 5 and 6, the rod 36 moves straight along the guide surface 26 c while pushing the intermediate portion of the wire 40.
[0032]
At this time, one end of the wire 40 is fixed to the outer periphery of the pulley 44c of the clutch 44, and the other end is wound around the pulley 44c at least once and then locked to the stopper portion 26b. For this reason, the wire 40 pushed out by the rod 36 draws out the wire portion wound around the pulley 44c of the clutch 44 by the amount drawn, that is, the length twice as long as the moving distance of the rod. As a result, the pulley 44c rotates by an angle corresponding to the drawing amount. In other words, as described above, the wire 40 exhibits a double speed increasing action by the so-called “slave” method, and rotates the pulley 44c that is the outer periphery of the clutch in the direction of the arrow in FIG.
[0033]
As a result, the pulley 44c and the plate 44b are displaced, and the plurality of cam surfaces on the inner periphery of the pulley 44c deform the plurality of protrusions 44bb of the plate 44b and push the protrusions 44bb inwardly, and the protrusions 44bb engage the sleeve 44a. The clutch device 44 is engaged (see FIG. 5). As a result, the speed increasing mechanism represented by the wire 40 and the pulley 44c and the retractor shaft 24 are coupled, and the retractor shaft 24 also rotates in the direction of the arrow A integrally with the rotation of the clutch device 44 driven by the pretensioner 12. As the retractor shaft 24 rotates, the reel 22 rotates in the webbing take-up direction and acts to remove the slack of the webbing, thereby restraining the occupant to the seat. The webbing is wound on the reel 22 within a very short time.
[0034]
After the webbing is wound up, a pulling force is applied to the webbing due to the inertial movement of the occupant during the collision. This pulling force is transmitted to the retractor shaft 24 via the webbing, the take-up reel 22 and the sleeve 44a. As described above, the emergency lock mechanism 14 prevents the retractor shaft 24 from rotating in the webbing pull-out direction on the right end side of the retractor shaft 24. Therefore, when the pull-out force exceeds a predetermined value, the retractor shaft (twisted shaft) 24a Plastically deformed, twisted and rotated. Accordingly, the webbing can be pulled out from the reel 22.
[0035]
When the retractor shaft 24 rotates in the webbing pull-out direction, the pulley 44c coupled to the retractor shaft 24 rotates in the reverse direction, and the wire 40 is wound (wound) around the outer periphery of the pulley 44c, as shown in FIG. The rod 36 is pushed back toward the initial position through the wire 40.
[0036]
As shown in FIGS. 9 to 11, when the rod 36 is pushed back further than the initial position of the rod 36, the communication port 26 e of the crimped ball storage space 26 a closed by the rod 36 opens, and the crimped ball 46 Can move to the internal space of the case. The wire 40 is further wound by the rotation of the clutch 44, and the caulking ball 46 is pulled out from the caulking ball storage space 26a. The caulking ball 46 is detached from the stopper portion 26b, and the locked state of the wire 40 is released.
[0037]
When the rod 36 returns to the inside of the pipe, as shown in FIG. 12, the hollow space 42a of the extruding member, the thin tube 36a of the rod, and the gas vent hole 36b allow the residual gas to flow into the cylinder space in the pipe 70. By returning from the rod 36, the rod 36 can be returned smoothly.
[0038]
When the wire 40 is disengaged from the stopper portion 26b, as shown in FIG. 13, there is no restriction on the rotation of the clutch 44, and further twisting rotation of the retractor shaft 24 coupled to the clutch 44 is allowed.
[0039]
Therefore, when an excessive acceleration is detected, the seat belt device fastens the webbing in a short time to restrain the occupant to the seat, and thereafter, when a load exceeding a predetermined value is applied to the occupant due to the inertial movement of the occupant, The webbing can be pulled out by twisting, and the load applied to the occupant can be suppressed. At this time, the pretensioner does not hinder the operation of the torsion shaft.
[0040]
FIG. 17 shows another embodiment of the present invention. In this example, the shear pin 26 cc is provided beside the caulking ball 46 to stabilize the initial arrangement state of the caulking ball 46. When the wire 40 is wound around the pulley 44c and the caulking ball 46 is about to come off from the stopper portion 26b, the caulking ball 46 breaks the shear pin 26cc and comes off from the stopper portion 26b.
[0041]
FIG. 18 shows another embodiment of the present invention. In this example, in order to fix the initial position of the rod 36, the shear pin 26cb formed in the case is used. By inserting the shear pin 26cb into the hole 36c of the rod 36, the initial position of the rod is determined. The shear pins 26cb and 26cc are formed, for example, by a casting mold simultaneously with the shear pin 26ca of the clutch portion 44. This eliminates the need for special parts.
[0042]
The wire releasing method of the present invention is not limited to the twisted shaft (torsion bar) method of the present embodiment, and can be combined with various types of energy absorbing mechanisms (devices). The present invention is not limited to this embodiment.
[0043]
【The invention's effect】
As described above, the seat belt device of the present invention is advantageous in that when the retractor shaft rotates as a torsion shaft, the pretensioner realizes a structure that does not hinder the rotation without using complicated parts. .
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a retractor of a seat belt device of the present invention in a partial cross section.
FIG. 2 is a cross-sectional view of the retractor shown in FIG. 1 in the AA direction.
FIG. 3 is a perspective view illustrating a clutch portion of the retractor shown in FIG.
FIG. 4 is an explanatory diagram for explaining the operation (non-coupled state) of the clutch unit.
FIG. 5 is an explanatory diagram for explaining the operation (coupled state) of the clutch unit;
FIG. 6 is an explanatory view showing a state after the pretensioner is operated.
7 is a cross-sectional view of the pretensioner portion shown in FIG. 2 in the CC direction.
FIG. 8 is an explanatory diagram for explaining a state in which a caulking ball is detached from a stopper portion (an engagement state of the caulking ball).
FIG. 9 is an explanatory diagram for explaining how the caulking ball is detached from the stopper portion (return of the rod).
FIG. 10 is an explanatory diagram illustrating a state in which the caulking ball is detached from the stopper portion (canceling of the caulking ball is released).
FIG. 11 is an explanatory diagram for explaining a state in which the caulking ball is detached from the stopper portion (disengagement of the caulking ball).
FIG. 12 is an explanatory diagram for explaining how gas escapes from a rod thin tube during an impact absorbing operation in which the rotation shaft of the reel is twisted.
FIG. 13 is an explanatory diagram for explaining a state (idling) after the caulking ball is removed from the stopper portion;
FIG. 14 is a perspective view illustrating an extruded member.
FIG. 15 is an explanatory diagram for explaining an example in which a push member is held by a protrusion in a pipe and a rod is held at an initial position.
FIG. 16 is an explanatory view of the rod as seen from the bottom side.
FIG. 17 is an explanatory diagram for explaining an example in which a caulking ball is held in a locking portion by a shear pin.
FIG. 18 is a perspective view illustrating an example in which a rod is held at an initial position by a shear pin.
[Explanation of symbols]
11 Spring mechanism 12 Pretensioner 14 Lock mechanism 24 Twist shaft 26 Case 26a Caulking ball storage space 26b Stopper part 26e Communication port 32 Gas generator 36 Rod 44 Clutch pipe 70
Cylindrical part 72
Square tubular part 74

Claims (2)

A reel for winding webbing,
A torsion shaft coupled to the reel;
A locking mechanism which is provided on one end side of the torsion shaft and prevents rotation of the torsion shaft in the webbing pull-out direction in the event of a collision or the like;
A pretensioner provided on the other end of the torsion shaft and rotating the torsion shaft in the winding direction of the webbing in the event of a collision,
The pretensioner is
A moving body arranged movably in the pipe;
A case having a storage portion that fixes the pipe and uses a part of the moving body as a door,
A gas generator that is attached to one end of the pipe and generates a high pressure to push the moving body to the other end of the pipe in the event of a collision ;
A clutch that is arranged coaxially with the torsion shaft and connects the clutch pulley and the torsion shaft when the clutch pulley rotates in the winding direction of the webbing ;
Wherein one end side on the outer periphery of the clutch pulley is wound reaches the receiving portion is the other end side via the movable body comprises a wire movement of the other end portion side is limited by the door portion ,
A seatbelt device in which the restriction on movement of the other end side of the wire is released when the moving body moves as a door body from a position to close the storage portion to an opening position . The seat belt device according to claim 1, wherein the other end side of the wire partially increases in diameter, and the increased portion is locked to a stopper portion in the storage portion .

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