KR100487350B1 - Webbing Winding Device - Google Patents

Abstract

It is an object of the present invention to provide a webbing take-up device capable of reducing the tensile load applied to the webbing during the force limiter operation without reducing the tensile force on the webbing during the pretensioner operation.

As the configuration, the pre-tension shaft portion 26 on one end side of the spool 18 is disposed on the drum 64 at a predetermined interval. The drum 64 is bitten by the pretension shaft portion 26 at the time of sudden deceleration. Since the pressure part 112 of the drive plate 80 presses the position near the lower end side of the engaging piece 76, the break part 72 is not broken so that the drum 64 moves the spool in the winding direction of the webbing 20. Rotate When the output force of a predetermined value or more acts on the webbing 20, the tip portion of the coupling piece 76 is pressed against the tip of the pressure piece 114, so that a large bending moment acts, so that the coupling piece 76 is broken (72). The torsion bar 24 is twisted and deformed by breaking at and continuing operation of the force limiter.

Description

Webbing take-up device

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pretensioner that tightens the webbing during rapid deceleration of a vehicle, and a webbing take-up device having a force limiter such that a tensile force greater than a predetermined value does not act on the webbing.

Some webbing take-up devices attached to a vehicle include a pretensioner that winds and tightens the webbing to tightly restrain the wearer when a large deceleration greater than or equal to a predetermined value is applied to the vehicle (Japanese Patent Laid-Open No. 4-92748). See, e.g., Japanese call. 15 shows a webbing take-up device 300 with such a pretensioner.

On the other hand, a webbing take-up device with a force limiter for preventing the tensile force applied to the webbing from becoming a predetermined value or more has been proposed.

However, in the webbing take-up device 300 shown in FIG. 15, the drum 310 is clamped to the wire 318 at the time of rapid deceleration of the vehicle, and the clamping portion 312 clamps the pretension shaft portion 308 so that the drum 310 Is rotated together with the spool 306, it is impossible to rotate the spool 306 further in the withdrawal direction of the webbing 304 due to the tension of the wire 318 in the state that the wire 318 is pulled out to the maximum. Do. Therefore, simply attaching the above-described force limiter to the webbing take-up device 300 does not release the tension of the webbing 304 by the pretensioner to sufficiently deform the torsion bar.

In order to solve such an unreasonable point, for example, a part of the member (for example, from the piston (not shown) in the cylinder 324 to the pretension shaft portion 308 in the state in which the wire 318 is pulled out to the maximum (for example) A breakage part is formed in the wire 318 or the drum 310 under a predetermined force or more that acts on the webbing 304, and the breakage of the breakage part 306 is independent of the pretensioner. 304 It is contemplated to be able to rotate in the extraction direction. However, this break must be configured so that it does not break during pretensioner operation, but breaks during force limiter operation, so that the tensile load applied to the webbing during operation of the force limiter without reducing the tension on the webbing during the pretensioner operation ( The release load necessary to release the tension of the webbing 304 by the pretensioner cannot be reduced only.

In view of this fact, it is an object of the present invention to propose a webbing take-up device capable of reducing the tensile load applied to the webbing during the operation of the force limiter without reducing the tensile force on the webbing during the pretensioner operation.

In the invention of claim 1, a spool in which the webbing is wound, an energy absorbing member deformed by the spool when a rotational force acts on the spool in the webbing pull-out direction during the sudden deceleration of the vehicle, and prevents an increase in the tension of the webbing; A rotation member that rotates in the webbing hook direction when the deceleration is greater than or equal to a predetermined value, and a connecting member connected to the spool when the deceleration is greater than or equal to a predetermined value, and the connection member Protrudes from the lower end side when the rotating member is rotated in the winding direction of the webbing, and the lower end side is pressed by the rotating member, and when the connecting member is rotated by the rotational force of the webbing pull-out direction of the spool, A pretensioner having a joining piece to which the portion on the tip side is pressed, and an energy absorbing portion by the rotational force in the webbing pull-out direction Is deformed and has a release portion for releasing the rotation stop in the webbing pull-out direction by the pretensioner when receiving the rotational force in the webbing pull-out direction when the portion of the tip side is pressed by the rotary member near the lower end side of the coupling piece. It features.

The pretensioner does not restrain the spool in the normal driving state of the vehicle in which the deceleration of the predetermined value or more does not work.

When the deceleration above the predetermined value acts, the rotating member rotates in the webbing take-up direction. The connecting member is also connected to the spool. In this way, the rotation of the rotating member is transmitted from the joining piece to the spool through the connecting member so that the webbing is wound on the spool, so that the webbing tightly restrains the mounter.

Next, when the webbing is pulled in the drawing direction, this tensile force is transmitted from the spool to the energy absorbing member. An energy absorbing action such as deformation of the energy absorbing member starts the movement of the force limiter so that the mounting force to the webbing wearer does not exceed a predetermined value. In response to this, when the webbing is further pulled out and the connecting member is rotated by the rotational force in the webbing pull-out direction of the spool, the portion of the tip side is pressed by the rotating member rather than near the lower end side of the engaging piece. At this time, a greater bending moment acts on the engaging piece than when the rotating member is rotated in the webbing take-up direction (near the lower end side of the engaging piece is pressed by the rotating member). Since the release portion releases the rotational determination in the webbing withdrawal direction by the pretensioner in response to the rotational force in the webbing withdrawal direction, the spool can be rotated relative to the pretensioner. Therefore, in this state, energy absorption continues and operation of the force limiter is continued so that the attachment force to the webbing wearer does not exceed a predetermined value.

In this case, when the energy absorbing member is deformed by the rotational force in the webbing pull-out direction, a portion of the tip side is pressed rather than in the vicinity of the joining piece, and a large bending moment acts on the joining piece so that the release portion releases the rotational stop in the webbing pull-out direction by the pretensioner In the pretensioner operation, near the lower end side of the engaging piece is pressed, and the release portion does not release the rotation stop in the webbing pull-out direction, so that the tensile load during the force limiter operation can be reduced without reducing the tension force during the pretensioner operation.

The release part may be any one that allows the spool to rotate relative to the pretensioner. Examples of the release part include a plastic deformation member, an elastic deformation member, a breaking member, a clutch, and a friction plate.

In the invention of claim 2, in the invention of claim 1, when the release portion is formed at the lower end side portion of the engaging piece and the vicinity of the lower end side of the engaging piece is pressed by the rotating member, the release portion is not broken, and the tip side is closer than the lower end side vicinity. When the part of the pressed portion is characterized in that the breaking portion having a breaking strength.

When the rotational member rotates in the webbing winding direction by a deceleration greater than a predetermined value, the rotational member presses near the lower end side of the engaging piece protruding from the connecting member, so that the bending moment acting on the fracture portion formed in this lower end portion is small. Substantially only the shear force is applied. The breaking portion is a strength that does not break only by the shear force by this pressure, so that the joining piece is pressed by the rotating member without breaking and the connecting member rotates. The connecting member is connected to the spool so that rotation of the rotating member in the webbing winding direction is transmitted to the spool through the connecting member, so that the spool rotates in the webbing winding direction to wind the webbing.

When the energy absorbing member deforms due to the rotational force in the webbing pull-out direction, when the connecting member rotates in the webbing pull-out direction under the rotational force in the webbing pull-out direction, the rotary member presses the portion on the tip side rather than near the lower end side of the engaging piece. For this reason, a larger bending moment acts (a shearing force also acts) to a fracture | rupture part compared with the case where the lower end side was pressed, and since a fracture part is an intensity | strength broken by the bending moment by this pressure, it fractures. By doing so, the spool is separated from the pretensioner, so that the spool can rotate freely with respect to the pretensioner.

Thus, when the rotating member rotates in the webbing take-up direction, the fracture of the fracture part is avoided, and when the connecting member rotates under the rotational force of the spool withdrawal direction of the spool, by breaking the fracture part, the tensile force during the pretensioner operation is not reduced. Only the tensile load during operation of the force limiter can be reduced.

(Example)

1-3 show the webbing retractor 10 which is one Embodiment of this invention.

The webbing retractor 10 includes a frame 12 attached to a vehicle (not shown). In the frame 12, a pair of support plates 14 and 16 are arranged in parallel. Between the support plates 14 and 16, the spool 18 is arrange | positioned in the substantially cylindrical shape, and the flange protruded in the radial direction at the both ends of an axial direction is arrange | positioned. One end of the webbing 20 is fixed to the spool 18 so that the webbing 20 is wound. FIG. 1 and FIG. 2 show a state in which such a webbing 20 is wound around the spool 18. 3 shows the state in which the webbing 20 is pulled out of the spool 18.

The torsion part 22 is arrange | positioned inside the spool 18 coaxially with the central axis of the spool 18. The torsion portion 22 has a cylindrical torsion bar 24 which is slightly longer than the axial length of the spool 18. The torsion bar 24 is formed of a material capable of plastic deformation such as metal, and plastic deformation and warp when a torsional force of a predetermined value or more acts in the circumferential direction.

On one side of the torsion bar 24, an insertion portion 24A having a hexagonal column shape is formed. The insertion portion 24A is inserted into the hexagonal insertion hole 34 (see Figs. 2 and 3) formed in the pretension shaft portion 26 constituting the torsion portion 22, and the torsion bar 24 and The pretension shaft portion 26 is integrally rotated.

The pretension shaft portion 26 has a diameter smaller than that of the clamped portion 28 and the clamped portion 28, which is formed substantially in a cylindrical shape, and is formed coaxially and integrally formed with the clamped portion 28. (See FIG. 2 and FIG. 3). On the outer circumference of the clamped portion 28, a plurality of projections 32 (see Fig. 1) whose ends are protruded at an acute angle in the same direction as the direction of the central axis of the torsion bar 24 have a predetermined interval in the circumferential direction. When the clamping portions 66 and 68 of the drum 64, which will be described later, pinch the clamped portion 28, they penetrate the inner surface of the drum 64 to prevent the drum 64 from revolving. do.

An outer gear tooth 36 is formed on the outer circumference of the gear part 30 so that the outer gear tooth 36 meshes with the inner gear tooth 38 formed on the inner circumference of the spool 18 over the entire circumference and the spool 18. And the pretension shaft portion 26 are integrally rotated. Accordingly, the torsion bar 24 rotates integrally with the spool 18 via the pretension shaft portion 26 at one end thereof.

The lock shaft 40 constituting the torsion portion 22 is disposed on the other end side (the upper left side in FIG. 1, the right side in FIGS. 2 and 3) of the torsion bar 24. The locking shaft 40 is formed in a substantially cylindrical shape, and the hexagonal insertion hole 44 is formed in the axial direction at one end thereof, and the cylindrical portion 42 and the cylindrical portion 42 having the male screw 46 cut off on the outer circumference thereof. The disk 48 formed on the other end and closing the insertion hole 44 and protruding radially outward of the cylindrical portion 42 and the fatigue piece protruding from the disk 48 in the shape of a frog leg. (50). The insertion hole 44 is inserted into the hexagonal column-shaped insertion portion 24B formed at the other end of the torsion bar 24 to rotate the torsion bar 24 and the lock shaft 40 integrally. In FIG. 1, this insertion part 24B is shown in the insertion hole 44 being inserted.

In this manner, the spool 18 is disposed between the support plates 14 and 16 in a state where the insertion portion 24B of the torsion bar 24 is inserted into the insertion hole 44, and for pretension from the support plate 14 side. While engaging the outer gear teeth 36 of the shaft portion 26 with the inner gear teeth 38 of the spool 18, the torsion bar 24 integral with the lock shaft 40 from the support plate 16 side is removed. 2 and 3, the torsion bar 24 is disposed coaxially with the spool 18 in the spool 18. As shown in FIG. At this time, the cylindrical portion 42 side is in contact with the inner circumferential surface of the spool 18 at an approximately center in the axial direction of the outer circumferential surface of the disk 48, and the central axis of the spool 18 and the central axis of the torsion bar 24 coincide with each other. The torsion part 22 is positioned. Moreover, it is supported by the support plate 16 of the frame 12 via the ring 52 so that the fatigue piece 50 side may rotate in the substantially axial direction center among the outer peripheral surfaces of the disk 48. Moreover, the part in which the outer gear teeth 36 are not formed in the gear part 30 of the pre-tension shaft part 26 is supported so that it may rotate to the cover drum 58 mentioned later. In this way, the spool 18 is supported to rotate on the frame 12.

The male thread 46 of the cylindrical portion 42 is formed in a substantially annular shape, and a return ring 54 in which a part of the circumferential direction is cut off and a female screw is cut inside is fitted. In the state where the torsion portion 22 is disposed inside the spool 18, the circumferential end face 54A of the return ring 54 protrudes along the axial direction of the spool 18 on the inner circumference of the spool 18. It touches the protrusion piece 56 (refer FIG. 2 and FIG. 3). In the normal state, the return ring 54 is at one end side of the male thread 46 (the pretension shaft portion 26 side, the position shown in FIG. 2), but the spool 18 is relative to the lock shaft 40. Rotation, the return ring 54 also rotates with the spool 18 and moves to the other end side (the disk 48 side, the position shown in FIG. 3). This movement is stopped by the return ring 54 touching the disc 48 and the rotation of the spool 18 with respect to the lock shaft 40 is also stopped.

An inertial lock mechanism (not shown) is provided on the outer side of the support plate 16 (the side opposite to the position where the spool 18 is arranged, the right side of Figs. 2 and 3). This inertial lock mechanism rotates the torsion portion 22 in the withdrawal direction of the webbing 20 when a deceleration of a predetermined value or more acts on the vehicle to which the webbing retractor 10 is attached or when the webbing 20 is rapidly drawn out. The fatigue piece 50 is locked so that it is suppressed, but the fatigue piece 50 is not locked in the winding direction of the webbing 20.

On the other hand, the outer side of the support plate 14 (left side of Figs. 2 and 3) of the cover drum having a receiving portion (60, 62) in diameter in a step shape toward the radially outward from the rotation axis of the torsion bar 24 ( 58) is fixed. The drum 64 to which the wire 94 mentioned later is wound is arrange | positioned coaxially with the torsion bar 24 in the accommodating part 60 (side close to the support plate 14) of the smaller diameter.

The drum 64 is made of a metal (for example, aluminum, etc.) that is softer than the lock shaft 40 or the pretension shaft portion 26. Moreover, as shown in detail in FIG. 4, the drum 64 is arrange | positioned so that the gripping parts 66 and 68 of a substantially return shape may oppose, and comprise a substantially cylindrical cylinder, and the gripping parts 66 and 68 in this state. The portions corresponding to both ends in the circumferential direction of the c) are connected to each other by a substantially S-shaped compression part 70 formed integrally with the clamping parts 66 and 68. Usually, as shown in FIG. 5 (A), the inner surface of the clamping portions 66 and 68 and the clamped portion 28 of the drum 64 are arranged in the housing portion 60 (see FIGS. 2 and 3). The drum 64 is separated from the pre-tension shaft portion 26 in the receiving portion 60 because a predetermined small distance from the tip of the protrusion 32 is generated, but the clamping portions 66 and 68 approach each other. Direction, the compression section 70 (see FIG. 4) compresses and deforms so that the clamping sections 66, 68 approach each other, as shown in FIG. 7A. (28) is interposed. Since the drum 64 is made of a metal softer than the shaft portion 26 for pretension, the projection 32 penetrates the inner surfaces of the clamping portions 66 and 68. For this reason, the drum 64 and the pre-tension shaft part 26 are united and rotate.

On the end surface 66A of the axial end one side of the clamping part 66, the engaging plate 76 of the substantially flat form toward radially outer side from the substantially circumferential direction is formed protruded. On the tip side of the joining piece 76, a portion 76B having a wider width than the joining piece 76 and having a thickness is formed and reinforced. Moreover, the lower end side part of the engaging piece 76 is set as the fracture | rupture part 72. As shown in FIG. When a force equal to or greater than a predetermined value is applied in the circumferential direction of the drum 64 to or near the tip (thick portion 76B) of the joining piece, the fracture portion 72 is broken under a bending moment. The breaking piece 72 breaks the engagement piece 76 from the drum 64. On the other hand, even if a force greater than or equal to a predetermined value is applied in the circumferential direction of the drum at a position near the lower end of the breaker 72, the bending moment received by the breaker 72 at this time is the tip (thick portion) of the coupling piece 76. 76B)) or smaller than when a force is applied in the vicinity thereof. The breaking portion 72 has a predetermined strength so that the breaking portion 72 does not break with this bending moment.

A positioning protrusion 73 is formed at the front end of the engaging portion 76. Moreover, the positioning projection 74 is formed in the end surface 66 of the axial direction end part of the clamping part 68. As shown in FIG. As shown in Fig. 5A, the positioning projections 73 and 74 are accommodated in the accommodation recesses 106 and 108 of the drive plate 80 described later in the attached state of the webbing take-up device 10. As shown in Figs. In this way, the drum 64 is positioned in the radial direction with respect to the cover drum 58.

Flange 78 protruding outward is formed in the other end side of the clamping part 66, 68, and the clamping part 66, 68 is reinforced.

On the outer side of the cover drum 58 (opposite side of the support plate 14, the left side of Figs. 2 and 3), a substantially disk-shaped drive plate 80 is disposed, and ribs 59 protruding from the cover drum 58 are formed. It is enclosed in three outer peripheries, and it can also rotate coaxially with the torsion bar 24. As shown in Fig. 5A, an insertion hole 82 into which the drum 64 is inserted is formed in the center of the drive plate 80. When the drum 64 is inserted, the end face 66A of the clamping portion 66 is formed. ) And end face 68A of clamping portion 68 contact drive plate 80 so that drum 64 is positioned in the axial direction.

The insertion hole 82 is formed with a substantially fan-shaped accommodating portion 110 that gradually widens along the radially outer side. The coupling piece 76 is accommodated in this accommodation part 110. In addition, when the cover drum 58 rotates relative to the drum 64 in the webbing take-up direction with respect to the drum 64, the pressure for pressing the vicinity of the lower end side (near the breakage portion 72) of the engaging piece 76. The part 112 is formed.

Moreover, the accommodating recess 106 which accommodates the positioning protrusion 73 is formed in the front-end | tip part of the accommodating part 110. As shown in FIG. In addition, at a position axially symmetrical with the receiving portion 110 with respect to the insertion hole 82, a receiving recess 108 for receiving the positioning projection 74 is formed.

The drive plate 80 is formed with a fixing portion 84 into which a body to which one end of the wire 94 is attached is inserted and fixed. The wire 94, one end of which is fixed to the fixing portion 84, is wound several times (almost twice in this embodiment) around the drum 64, and in the cylinder 86 in which the other end is provided in the frame 12. It is wound around the piston 88 (refer FIG. 5 (A)), and is fixed to the exterior of the cylinder 86. As shown in FIG. When a sensor (not shown) detects that a deceleration greater than a predetermined value is applied to the vehicle to which the webbing retractor 10 is attached, a gas generator (not shown) in the base cartridge 90 installed in the frame 12 operates. As shown in Figs. 6B, 7B and 8B and 9B, the piston 88 is rapidly moved into the cylinder 86. As shown in Figs. By the movement of the piston 88, the wire 94 is rapidly drawn to exert a rotational force on the drive plate 80.

As shown in Figs. 1 and 5 (A), the safety pins 92 protrude from the frame 12 through the cover drum 58, and the safety pins 92 are formed on the drive plate 80. In general, the drive plate 80 does not rotate in the winding direction of the webbing 20 (in the direction of arrow A in FIG. 5 (A)), but the wire 94 is rapidly When pulled into the 86 and a rotational force greater than or equal to a predetermined value acts on the drive plate 80, the shear pin 92 is pressed by the recess 101 to break and the drive plate 80 rotates.

An outer ring shape stopper plate 96 is disposed outside the drive plate 80. The stopper plate 96 is supported by the positioning member (not shown) so as to be able to rotate coaxially with the torsion bar and about the central axis J (see Fig. 1) of the torsion bar 24. (In addition, this stopper plate 96 and the cover plate 102 which are mentioned later are abbreviate | omitted in FIG. 2 and FIG. 3 for the convenience of illustration.) In the stopper plate 96, it extends toward a radially outer side and a tip part is a drive. The moving projection 98 bent at a right angle toward the plate 80 side is formed. The distal end of the moving protrusion 98 is located in the long groove 100 cut in an arc shape along the circumferential direction of the drive plate 80 and moves by the relative rotation of the stopper plate 96 and the drive plate 80. 98 moves in the long groove 100. The center angle of the long groove 100 is set to about 150 degrees so that the stopper plate 96 and the drive plate 80 rotate about 150 degrees relative.

The stopper plate 96 is formed with a pressure piece 114 protruding from the moving projection 98 toward the rear side in the webbing take-up direction (the arrow A direction side in FIG. 5). The pressure piece 114 is formed in a substantially wedge shape so that the position of the tip can reach the tip of the coupling piece 76 from the side in the attached state. As shown in Fig. 7A, the moving projection 98 touches the stopper projection 104 described later and the drum (in the direction of the webbing pull-out direction (arrow B direction) of the stopper plate 96 is stopped) in the webbing pull-out direction. When 64 is about to rotate further, the tip of the coupling piece 76 is pressed against the tip of the pressure piece 114. As a result, a shear force is applied to the breakage portion 72 of the engagement piece 76, and a large bending moment acts to break the engagement piece 76 at the breakage portion 72.

A cover plate 102 is disposed outside the stopper plate 96 and fixed to the cover drum 58. The drum plate 64, the drive plate 80, and the stopper plate 96 are held by the cover plates 102 in the receiving portions 60, 62 of the cover drum 58.

In the cover plate 102, a stopper protrusion 104 protrudes toward the stopper plate 96. The stopper protrusion 104 is of a length which touches the moving protrusion 98 but does not enter the elongated groove 100. As shown in FIG. 5 (A), when the deceleration more than the predetermined value does not act on the webbing take-up device 10, the stopper is placed on the lower right side (the winding direction side of the webbing 20) on the stopper protrusion 104 in the drawing. The moving projection 98 of the plate 96 is located and the one end wall 100A of the elongate groove 100 of the drive plate 80 is located in the lower right side.

In addition, when the wire 94 is pulled into the cylinder 86 and the drive plate 80 rotates in the webbing take-up direction (the arrow A direction in Fig. 5A), the pressure portion 112 is near the lower end side of the engaging piece 76. Because of pressing, the drum 64 also rotates as shown in Fig. 8A. As the drive plate 80 further rotates, as shown in FIG. 9A, the rotation of the drum 64 stops when the pressure piece 114 touches the stopper protrusion 104, and the moving protrusion 98 has a long groove 100. ), The stopper plate 96 further rotates. Then, the wire 94 is pulled into the cylinder 86 by the piston 88 so that the piston 88 touches the bottom in the cylinder 86 so that the pulling of the wire 94 is completed and the rotation of the drive plate 80 stops.

As described above, the drive plate 80 rotates about 360 ° with the stopper plate 96 at the beginning of rotation, and then rotates about 150 ° only with the drive plate 80, thus rotating about 510 ° from the start of rotation to the end of rotation. In addition, the rotation amount of the drive plate 80 can be changed by changing the rotation amount of the relative rotation of the drive plate 80 and the stopper plate 96 by changing the length of the long groove 100. In addition, during the rotation of the drive plate 80, the moving protrusion 98 may be at any position within the long groove 100, and the drive plate 80 may rotate about 510 degrees from the start of rotation to the end of rotation.

Next, the operation and action of the webbing take-up device 10 of the present embodiment will be described.

In a normal state, that is, when the deceleration of the vehicle to which the webbing retractor 10 is attached does not reach a predetermined value, the inertial lock mechanism (not shown) does not lock the fatigue piece 50. Since the gas generator in the base cartridge 90 does not operate either, the wire 94 is not pulled into the cylinder 86. For this reason, the spool 18 (refer FIG. 1 thru | or 3) rotates freely, and the webbing 20 can be taken out and wound up.

When the deceleration above the predetermined value acts on the vehicle, the inertial locking mechanism locks the rotation of the fatigue piece 50 in the drawing direction of the webbing 20 (arrow B direction in Fig. 5A). The spool 18 which rotates together with the spool 18 is also locked to rotate in the withdrawal direction of the webbing 20 so that the webbing 20 is no longer pulled out.

In addition, since the gas generator operates to move the piston 88 toward the inside of the cylinder 86 as shown in Fig. 6B, the wire 94 is pulled into the cylinder 86 rapidly. Here, the drive plate 80 does not rotate because the rotation is stopped by the shear pin 92. In addition, since the positioning projections 73 and 74 are accommodated in the receiving recesses 106 and 108, the drum 64 does not rotate either. For this reason, in the drum 64 in which the wire 94 is wound, the compression part 70 (refer to FIG. 4) which is rapidly clamped by this wire compressively deforms, and the clamping part 66, as shown in FIG. 68 approaches and interposes the clamped portion 28 of the pretension shaft portion 26. At this time, since the wire 94 first tightens the upper portion of the drum 64 in FIG. 6A, the shaft center of the drum 64 deviates from the shaft center of the clamped portion 28. ), The upper part of the drawing is bitten by the clamped portion 28 before the lower part of the drawing. Due to this movement, the positioning projections 73 and 74 also move downward with respect to the receiving recesses 106 and 108, so that the positioning projections 73 and 74 are broken. As shown in Fig. 7B, when the wire 94 is further pulled into the cylinder 86, as shown in Fig. 7A, the lower portion of the drum 64 is also caught by the clamped portion 74 and the drum 64 The drum 64 and the pretension shaft portion 26 are united by being pinched by the clamped portion 74 over the entire circumference. At this time, the shaft center of the drum 64 coincides with the shaft center of the clamped portion 74 again.

As the wire 94 is further pulled into the cylinder 86, a rotational force acts on the drive plate 80 such that the recess 101 presses and breaks the sewer pin 92. In this way, as shown to 8A, the drive plate 80 rotates to the winding direction (arrow A direction) of a webbing. The engaging piece 76 of the drum 64 is accommodated in the receiving part 110 of the drive plate 80, and the breaking part 72 because the pressure part 112 presses the position near the lower end side of the engaging piece 76. The bending moment acting on the s) is considerably small so that only the shear force acts on the fracture portion 72 substantially. Since the strength of the breaking portion 72 is such that it is not broken by this shearing force, the drum 64 rotates integrally with the drive plate 80 in the webbing pull-out direction without breaking the breaking portion 72. .

The outer gear teeth 36 formed in the gear portion 30 of the pretension shaft portion 26 are engaged with the inner gear teeth 38 of the inner circumference of the spool 18, and the inertial lock mechanism (not shown) Since the locking shaft 40 does not lock the rotation of the webbing 20 in the winding direction (arrow A direction), the spool 18 is moved through the pretension shaft portion 26 by the rotation of the drum 64. It rotates in the winding direction (arrow A direction) of the webbing 20. As shown in FIG. As shown in Fig. 9 (B), when the piston 88 moves inside the cylinder 86 to the corner and the wire 94 is pulled deepest into the cylinder 86, as shown in Fig. 9A, the drive plate is shown. 80 rotates about 510 ° in its initial state to pull the webbing 20 most taut. In this way, the webbing 20 is tightly mounted to the webbing 20 mounter.

Next, when the output force of the webbing 20 is greater than a predetermined value by the inertial force of the webbing 20 mounter, the force is applied by the spool 18 in the drawing direction of the webbing 20 (arrow B direction in Fig. 10 (A)). It acts as a turning force to rotate. The inertial lock mechanism not shown here locks the lock shaft 40 to rotate in the withdrawal direction of the webbing 20, so that the insertion portion 24B of the other end is inserted into the insertion hole 44 of the lock shaft 40. The rotation of the torsion bar 24 into which the) is inserted is also locked at the other end side. On the other hand, the insertion portion 24A of one end side of the torsion bar 24 is inserted into the pretension shaft portion 26 so that the pretension shaft portion 26 has the outer gear teeth 36 and the inner gear teeth 38. ) Rotates in unison with the spool 18 by engagement. The rotational force of the spool 18 is transmitted to the torsion bar 24 through the pretension shaft portion 26 so that the torsion bar 24 is plastically deformed and starts to warp so that a tension force of more than a predetermined value does not act on the webbing 20. Start the action of the force limiter to avoid.

At this time, if the spool 18 rotates with respect to the lock shaft 40, the end surface 54A of the return ring 54 is pressed against the projection 56 and the return ring 54 rotates to move toward the disc 48. To start.

In addition, since the drum 64 bitten by the clamped portion 28 of the pretension shaft portion 26 also rotates in the drawing direction of the webbing 20 (arrow B direction in Fig. 9 (A)), the drive plate 80 also The wire 94 is pulled in the cylinder 86 by rotating in the drawing direction of the webbing 20, and the piston 88 moves in the cylinder 86 to the left side as shown in Fig. 10B.

At this time, as shown in Fig. 10A, the drum 64 and the drive plate are pressed because the drum 64 presses the pressure part 112 of the drive plate 80 in the vicinity of the lower end side of the engaging piece 76. 80 integrally rotates in the drawing direction of the webbing (arrow B direction). In addition, since the moving projection 98 is accommodated in the elongate groove 100, the drive plate 80 also rotates relative to the stopper plate 96 in the drawing direction of the webbing 20 (arrow B direction).

As shown in Fig. 11A, the drive plate 80 is rotated to the same state as the initial state (the same state as shown in Fig. 5A) so that the moving protrusion 98 touches the stopper protrusion 104. The rotation of the surface stopper plate 96 is stopped. In this state, if the rotational force is further applied to the spool 18 in the drawing direction (arrow B direction) of the webbing 20, the drum 64 attempts to rotate in the drawing direction of the webbing 20. The part is pressed to the tip of the pressure piece 114. As a result, a shear force is applied to the fracture portion 72 of the engagement piece 76 and a large bending moment acts, so that the engagement piece 76 fractures at the fracture portion 72 as shown in FIG.

As a result, as shown in FIG. 13, the pretension shaft portion 26 can be separated from the drive plate 80 and rotated relative to the drive plate 80, so that the torsion bar 24 is further twisted. Operation continues and the spool 18 rotates in the extraction direction of the webbing 20. The torsion bar 24 is distorted and deformed until the torsion force of the torsion bar 24 is balanced by the rotational force acting on the shaft 26 for pretension through the spool 18 by the withdrawal of the webbing 20. do.

As shown in Fig. 14A, the gripping portions 66 and 68, the pretension shaft portion 26, and the spool 18 (Figs. 1 to Fig. 1) correspond to the rotation angles of the torsion bar 24 due to the twisting deformation. 3) is also rotated to act as a force limiter so that the webbing 20 is drawn out so that the tensile load applied to the webbing 20 does not exceed a predetermined value.

In addition, when the rotational force acting on the spool 18 is large, as shown in FIG. 3, the return ring 54 moving toward the disk 48 touches the disk 48, and the return ring 54 moves and rotates further. You will not. By doing so, the rotation of the spool 18 is also stopped, thereby preventing excessive twisting deformation of the torsion bar 24 and preventing the torsion bar 24 from being twisted. In addition, since the return ring 54 rotates to contact the disc 48 to stop the rotation of the spool 18, the spool 18 with respect to the lock shaft 40 is adjusted by adjusting the initial position of the return ring 54. You can change the relative rotation of). In this way, the amount of twisting of the torsion bar 24 can be adjusted to adjust the amount of drawing of the webbing 20 during operation of the force limiter.

Thus, in the webbing retractor 10 of this embodiment, when the drum 64 clamps the pre-tension shaft part 26, when the rotational force of the webbing 20 pull out direction acts on the spool 18, the drum 64 will be carried out. 76A of the breaks are broken so that the pre-tension shaft portion 26 can rotate relative to the drive plate 80 of the pretensioner, so that the torsion bar 24 is sufficiently twisted and deformed to act as a force limiter. It is possible.

In the pretensioning operation, the vicinity of the lower end side of the engaging piece 76 is pressed, so that even if the pressure is increased, the bending moment acting on the fracture portion 72 becomes small, so that the fracture portion 72 does not break. On the other hand, in the operation of the force limiter, the tip of the engaging piece 76 is pressed, so that the break 72 can be broken by applying a large bending moment to the break 72 with a small pressure. For this reason, only the tensile load (release load) at the time of a force limiter operation can be made small, without reducing the tension force with respect to the webbing 20 at the time of pretensioner operation.

The release portion is not limited to the above-described breaking portion 76A, but the pretensioner and the spool 18 are integrated in the rotational load of the webbing 20 withdrawal direction by the pretensioner, and the spool 18 with the load in the webbing 20 withdrawal direction. ) Can be rotated relative to the pretensioner can take a variety of configurations. For example, instead of the fracture portion 72, a deformation portion for plastic deformation or elastic deformation is formed, and the deformation portion is deformed by a shear force or a bending force acting on the coupling piece 76, so that the webbing 20 is pulled out by the pretensioner. It is sufficient to release the rotation stop and allow the pretension shaft portion 26 to rotate relative to the drive plate 80 of the pretensioner. In addition, instead of the engaging piece 76, a gear that engages with each other is formed on the outer circumference of the drum 64 and the inner circumference of the insertion hole 82 of the drive plate 80, and the gear is broken, thereby causing the pretension shaft portion 26 to break. May be rotated relative to the drive plate 80. In addition, a clutch, a friction plate, etc. may be sufficient.

Also, the energy absorbing member is not limited to the torsion bar 24 described above, but is deformed by rotation of the spool 18 in the drawing direction of the webbing 20 or generates friction to flow viscous fluid so as to cause kinetic energy. What is necessary is just to absorb and to prevent the tension increase of the webbing 20. For example, the tension of the webbing 20 may be prevented by moving in the axial direction of the spool 18 by the rotation of the spool 18 and receiving this resistance by deformation or friction. These energy absorbing members may not be coaxial with the spool 18.

In addition, in the above description, when a deceleration of more than a predetermined value is sensed, the lock portion for locking the spool 18 in the drawing direction of the webbing 20 and allowing only the rotation of the webbing 20 in the winding direction is rotated. Although the lock part is installed at the other end, the lock part is not necessarily required. For example, after mounting the webbing 20 regardless of the magnitude of the deceleration, the rotation of the spool 18 in the drawing direction is locked and the webbing 20 is locked. The rotation may be allowed only in the winding direction. If the rotation of the spool 18 can be locked, it is not necessary to be provided at the other end of the spool 18, and may be attached to the spool 18 through an energy absorbing member.

In addition, although the torsion bar 24 rotates with the spool through the pre-tension shaft part 26 attached to one end side of the spool 18 in the above description, the torsion bar 24 and the spool 18 are shown. ) And the connection structure of the pretension shaft portion 26 is not limited thereto, and the pretension shaft portion 26 or the pretensioner is connected to the spool 18, and the torsion bar ( 24) should be attached. For example, the torsion bar 24 is attached to the other end side of the spool 18 and may rotate together with the spool 18.

Further, the stopper plate 96 is engaged with the stopper plate 96 while the drive plate 80 rotated in the winding direction of the webbing 20 in the pretension operation during sudden deceleration of the vehicle presses the drum 64 or the force limiter is in operation. The position at which the 76 is pressed is not necessarily limited to the above positions (near the lower end side and the tip end vicinity of the engaging piece 76), and these positions are determined in a relative relationship. That is, if the position where the drive plate presses the drum 64 in the pretension operation is closer to the breaker 72 than the position where the stopper plate 96 presses the engaging piece 76 while the force limiter is operating, the pretension operation The bending moment acting on the break 72 can be made smaller than the bending moment acting on the break 72 during the force limiter operation. For this reason, the strength of the breaking part 72 can be set so that it may not be broken by the bending moment which acts in a pretension operation | movement, but by the bending moment which acts during a force limiter operation | movement. In addition, if such a condition is satisfied, the protruding direction of the coupling piece 76 is not limited to the radially outer side of the drum 64, but may be protruded in the axial direction of the drum 64, for example.

In the invention of claim 1, a spool in which the webbing is wound, an energy absorbing member deformed by the spool when a rotational force acts on the spool in the webbing pull-out direction during the sudden deceleration of the vehicle, and prevents an increase in the tension of the webbing; A rotation member that rotates in the webbing hook direction when the deceleration is greater than or equal to a predetermined value, and a connecting member connected to the spool when the deceleration is greater than or equal to a predetermined value, and the connection member Protrudes from the lower end side when the rotating member is rotated in the winding direction of the webbing, and the lower end side is pressed by the rotating member, and when the connecting member is rotated by the rotational force of the webbing pull-out direction of the spool, A pretensioner having a joining piece to which the portion on the tip side is pressed, and an energy absorbing portion by the rotational force in the webbing pull-out direction Is deformed to have a release portion for releasing the rotation stop in the webbing pull-out direction by the pretensioner when receiving a rotational force in the webbing pull-out direction when the portion of the tip side is pressed by the rotary member near the lower end side of the coupling piece. Only the tensile load during the force limiter operation can be reduced without reducing the tensile force during the pretensioner operation.

In the invention of claim 2, in the invention of claim 1, the release portion is formed at the lower end side portion of the coupling piece and is not broken when the lower end side vicinity of the coupling piece is pressed by the rotating member, and the tip side is closer than the lower end side vicinity. When the part is pressed, it is a breaking part that has a breaking strength. Therefore, when the rotating member is rotated in the webbing winding direction, the breaking part is avoided, and when the connecting member is rotated by the rotational force of the spool in the webbing pull-out direction, it is broken. By breaking the part, only the tensile load during the force limiter operation can be reduced without reducing the tensile force during the pretensioner operation.

1 is an exploded perspective view of a webbing retractor according to one embodiment of the present invention;

2 is a cross-sectional view of a webbing take-up device of one embodiment of the present invention cut in a plane including an axis;

3 is a cross-sectional view showing a state in which the webbing is drawn out in the state shown in FIG. 2;

4 is a perspective view showing a drum of the webbing take-up device of one embodiment of the present invention;

Fig. 5A is a side view of an essential part of the webbing take-up device of one embodiment of the present invention, and Fig. 5B is a sectional view of a cylinder of the webbing take-up device of one embodiment of the present invention;

Fig. 6 (A) is a side view of the main part of the state in which the drum is indented by the pretension shaft in Fig. 5A, and Fig. 6 (B) is a sectional view of the cylinder at this time,

Fig. 7A is a side view of the main part of the drive plate in the webbing winding direction in Fig. 6A, and Fig. 7B is a sectional view of the cylinder at this time;

Fig. 8 (A) is a side view of the main part of the state in which the drive plate is rotated in the webbing winding direction in Fig. 7 (A), and Fig. 8 (B) is a sectional view of the cylinder at this time,

Fig. 9A is a side view of the main part of the drive plate in the webbing winding direction in Fig. 8A, and Fig. 9B is a sectional view of the cylinder at this time;

Fig. 10 (A) is a side view of the main part of the drive plate in the webbing pull-out direction in Fig. 9A, and Fig. 9B is a sectional view of the cylinder at this time,

Fig. 11A is a side view of the main part of the drive plate in the webbing pull-out direction in Fig. 10A, and Fig. 10B is a sectional view of the cylinder at this time;

Fig. 12 (A) is a side view of the main portion showing the state in which the drive plate is rotated in the webbing pull-out direction in Fig. 11 (A) to break the breaking portion of the engaging piece, and Fig. 11 (B) is a sectional view of the cylinder at this time,

Fig. 13 (A) is a side view of the main portion showing a state in which the drive plate is rotated in the webbing pull-out direction in Fig. 12 (A) so that the broken portion of the joining piece is broken, Fig. 12 (B) is a sectional view of the cylinder at this time,

Fig. 14A is a side view of the main part in the state where the clamping part of the drum and the pretension shaft part are rotated in the webbing pull-out direction in Fig. 13A, and Fig. 13B is a sectional view of the cylinder at this time;

15 is a perspective exploded view of a conventional webbing retractor.

*** Explanation of the main symbols used in the drawings ***

10: webbing retractor 18: spool

22: torsion part

24: torsion bar (energy absorbing member)

26: shaft portion for pretension

40: shaft portion for locking 64: drum (connection member, pretensioner)

76: engaging piece (pretensioner) 76A: breaking part (release part)

80: drive plate (rotating member, pretensioner)

86: cylinder (pretensioner) 88: piston (pretensioner)

94: wire (pretensioner)

96: stopper plate (rotating member, pretensioner)

Claims (2)

The spool on which webbing is wound, An energy absorbing member that is deformed by the spool to prevent an increase in tension of the webbing when a rotational force is applied to the spool in the webbing pull-out direction during rapid deceleration of the vehicle; A rotation member that rotates in the webbing winding direction when a deceleration greater than or equal to a predetermined value acts as a unit; and a connecting member connected to the spool when a deceleration greater than or equal to a predetermined value acts; Protrudes from the lower end side when the rotating member is rotated in the winding direction of the webbing, and the lower end side is pressed by the rotating member, and when the connecting member is rotated by the rotational force of the webbing pull-out direction of the spool, Pretensioner with joining piece that part of tip side is pressed In the webbing retractor provided, The coupling piece receives the webbing pulled out by the pretensioner when the energy absorbing member is deformed by the rotational force in the webbing pull-out direction and receives a rotational force in the webbing pull-out direction when the portion of the tip side is pressed by the rotating member rather than near the lower end side. Acting as a release for releasing the rotation stop in the direction Webbing take-up device characterized in that. The method of claim 1, The coupling piece, A webbing take-up device, characterized in that it does not break when the vicinity of the lower end side is pressed by the rotating member, and has a strength that the vicinity of the lower end side breaks when the portion of the tip side is pressed more than the vicinity of the lower end side.