JP5676346B2 - Webbing take-up device - Google Patents

Description

  The present invention relates to a webbing take-up device provided with an energy absorbing member on the radially inner side of a take-up shaft.

  In the seat belt device described in Patent Document 1 below, the movable latching and the concave ring are rotatably provided on the retractor base, and the wire is wound around the concave ring by rotating the concave ring. A second pole is provided outside the bobbin. When the rotation speed of the bobbin is equal to or higher than a predetermined value, the second pole meshes with the movable latching, and the movable latching and the concave ring are interlocked with the bobbin.

  In an emergency of the vehicle, the lock mechanism is activated to prevent the locking mechanism from rotating in the pull-out direction of the locking base. When a load in the pulling direction is further applied to the bobbin in this state, the deformed portion of the torsion bar provided in the bobbin is twisted, and the bobbin rotates relative to the locking base. Thereby, the deformation | transformation part torsionally deforms and the energy which acts on a passenger | crew is absorbed. At this time, a force limiter load is applied to the webbing.

  Further, when the rotation speed of the bobbin becomes a predetermined value or more, the second pole meshes with the movable latching, and the movable latching and the concave ring rotate in conjunction with the bobbin, whereby the wire is wound around the concave ring. Thereby, the energy absorption accompanying the plastic deformation of the wire is added to the energy absorption accompanying the torsional deformation of the deformed portion of the torsion bar. Therefore, the load value of the force limiter load is further increased, and the load value of the force limiter load can be increased stepwise according to the magnitude of the impact load.

JP 2001-206193 A

  However, in this seat belt device, since the second pole, the movable latching, the concave ring, and the wire are arranged on the outside in the axial direction of the bobbin, there is a problem that the seat belt device is enlarged in the axial direction of the bobbin.

  In view of the above facts, the present invention has an object to provide a webbing take-up device that can increase the load value of a force limiter load stepwise while suppressing an increase in the size of the take-up shaft in the axial direction. .

The webbing take-up device according to claim 1 is provided on the one end side in the axial direction of the take-up shaft, the take-up shaft being rotated in the pull-out direction when the occupant restraining webbing is drawn out, and the vehicle sudden deceleration A locking mechanism that prevents the winding shaft from rotating in the pull-out direction at least one time when the winding shaft suddenly rotates in the pull-out direction, and the winding shaft radially inward of the winding shaft. A lock mechanism connecting portion provided coaxially with the take-up shaft and connected to the lock mechanism on one end side in the axial direction and a take-up shaft connection connected to the take-up shaft on the other end side in the axial direction so as to be integrally rotatable. And an engaging portion between the lock mechanism connecting portion and the take-up shaft connecting portion, and the mechanical strength of the portion on one end side in the axial direction from the engaging portion is higher than that of the engaging portion. Energy absorbing member set larger than the mechanical strength of the other axial end , Provided on the take-up shaft, configured to be able to contact and separate with respect to the engagement portion, and engaged with the engagement portion to transmit the rotation of the take-up shaft in the pull-out direction to the energy absorbing member. A rotation transmitting portion and a weight portion are provided in the take-up shaft, and the take-up shaft rotates in the pull-out direction at a first speed or higher so that the take-up shaft is rotated in the radial direction by centrifugal force. A speed detecting unit that is rotated outward to rotate the rotation transmitting unit radially inward of the winding shaft and engage the engaging unit.

  In the webbing take-up device according to the first aspect, the lock mechanism connecting portion is provided on one end side in the axial direction of the energy absorbing member, and the lock mechanism is connected to the lock mechanism connecting portion. In addition, a winding shaft coupling portion is provided on the other axial end side of the energy absorbing member, and the winding shaft is coupled to the winding shaft coupling portion so as to be integrally rotatable with the energy absorbing member. Thereby, the winding shaft is connected to the lock mechanism via the energy absorbing member. The energy absorbing member has an engaging portion between the lock mechanism connecting portion and the take-up shaft connecting portion, and the mechanical strength of the portion on the one end side in the axial direction from the engaging portion is higher than that of the engaging portion. It is set larger than the mechanical strength of the portion on the other end side in the direction.

  When the webbing is suddenly drawn and the take-up shaft is suddenly rotated in the draw-out direction or when the vehicle is suddenly decelerated, the lock mechanism prevents the take-up shaft from rotating in the pull-out direction. For this reason, the rotation of the energy absorbing member is also prevented by the lock mechanism. As a result, a torsional load is applied to the energy absorbing member via the webbing and the winding shaft by the inertial energy of the occupant. When this torsional load is greater than the mechanical strength of the portion on the other end side in the axial direction from the engaging portion of the energy absorbing member, the energy absorbing member is mainly disposed between the engaging portion and the take-up shaft connecting portion. Twisted. Therefore, the torsional load of the energy absorbing member acts on the webbing as a force limiter load, and the take-up shaft rotates in the pull-out direction so that the energy acting on the occupant can be absorbed.

Further, when the take-up shaft rotates in the pull-out direction at the first speed or higher, the speed detection unit is rotated outward in the radial direction of the take-up shaft by centrifugal force, and the rotation transmission unit is turned to the diameter of the take-up shaft. Rotate inward in the direction and engage with the engaging portion. As a result, the rotation transmitting portion transmits the rotation of the take-up shaft in the pull-out direction to the energy absorbing member, so that the rotational force in the pull-out direction of the take-up shaft is closer to one end in the axial direction than the engaging portion of the energy absorbing member. It is transmitted to the lock mechanism through the part. At this time, when the torsional load applied to the energy absorbing member via the webbing and the winding shaft by the inertia energy of the occupant is larger than the mechanical strength of the portion on the one end side in the axial direction from the engaging portion of the energy absorbing member. The energy absorbing member is twisted between the engaging portion and the lock mechanism connecting portion. For this reason, the torsional load of the energy absorbing member acts on the webbing as a force limiter load, and the take-up shaft rotates in the pull-out direction to absorb energy acting on the occupant. At this time, the mechanical strength of the portion on the one end side in the axial direction from the engaging portion of the energy absorbing member is set larger than the mechanical strength of the portion on the other end side in the axial direction from the engaging portion of the energy absorbing member. Therefore, the force limiter load applied to the webbing is increased. As a result, the load value of the force limiter load can be increased stepwise in accordance with the rotational speed of the take-up shaft in the pull-out direction.

Here, a speed detection unit configured to include a weight unit is provided in the winding shaft, and the rotation transmission unit is engaged with the engaging portion of the energy absorbing member provided on the radially inner side of the winding shaft. Is done. For this reason, the speed detection section can be engaged with the rotation transmission portion to the engaging portion in accordance with the rotational speed of the winding shaft.

  The webbing take-up device according to claim 2 is the webbing take-up device according to claim 1, wherein the engaging portion includes a first engaging portion, the first engaging portion, and the lock mechanism connecting portion. A second engaging portion disposed between the first engaging portion and the second engaging portion. The second transmitting portion engages with the second engaging portion. A second rotation transmission unit, and the speed detection unit engages the first rotation transmission unit with the first engagement unit when the winding shaft rotates in the pull-out direction at the first speed or higher. A first speed detecting section to be engaged with the second engaging section by rotating the take-up shaft in a pulling-out direction at a second speed higher than the first speed. A two-speed detection unit, wherein the energy absorbing member includes a first deformation unit provided between the winding shaft coupling unit and the first engagement unit; A second deforming portion provided between the first engaging portion and the second engaging portion; a third deforming portion provided between the second engaging portion and the lock mechanism connecting portion; And the mechanical strength of the second deformable portion is set higher than the mechanical strength of the first deformable portion, and the mechanical strength of the third deformable portion is mechanical of the second deformable portion. It is set higher than the strength.

  In the webbing take-up device according to the second aspect, the mechanical strength of the first deformation portion is set lower than the mechanical strength of the second deformation portion and the third deformation portion. For this reason, when the webbing is suddenly drawn and the take-up shaft rotates suddenly in the pull-out direction or when the vehicle suddenly decelerates, the lock mechanism prevents the take-up shaft from rotating in the pull-out direction, and the energy absorbing member When the applied torsional load is greater than the mechanical strength of the first deformable portion, the first deformable portion is mainly twisted. As a result, a force limiter load accompanying the torsional deformation of the first deforming portion is applied to the webbing, and the take-up shaft rotates in the pull-out direction to absorb energy acting on the occupant.

  Further, when the take-up shaft rotates in the pull-out direction at the first speed or higher, the first speed detection unit engages the first rotation transmission unit with the first engagement unit. As a result, the first rotation transmission unit transmits the rotation of the take-up shaft in the pull-out direction to the energy absorbing member. Is transmitted to. In this state, when the torsional load applied to the energy absorbing member is larger than the mechanical strength of the second deformable portion, the mechanical strength of the second deformable portion is larger than the mechanical strength of the third deformable portion. Since it is low, the second deforming portion is mainly twisted. Thereby, the force limiter load accompanying the torsional deformation of the second deforming portion is added to the webbing. At this time, since the mechanical strength of the second deformable portion is set larger than the mechanical strength of the first deformable portion, the force limiter load can be increased.

  Further, when the take-up shaft rotates in the pull-out direction at a second speed higher than the first speed, the second speed detection unit engages the second rotation transmission unit with the second engagement unit. Thereby, since the 2nd rotation transmission part transmits rotation of the drawing-out direction of a winding axis to an energy absorption member, the rotational force of the drawing-out direction of a winding axis is transmitted to a lock mechanism via the 3rd deformation part. In this state, when the torsional load applied to the energy absorbing member is greater than the mechanical strength of the third deformable portion, the third deformable portion is twisted. Thereby, the force limiter load accompanying the torsional deformation of the third deforming portion is added to the webbing. At this time, since the mechanical strength of the third deformable portion is set larger than the mechanical strength of the second deformable portion, the force limiter load can be further increased. As described above, the load value of the force limiter load can be set in three stages according to the rotational speed of the take-up shaft in the pull-out direction.

  The webbing take-up device according to claim 3 is the webbing take-up device according to claim 2, wherein the first deforming portion, the second deforming portion, and the third deforming portion are integrally provided in a shaft shape. The outer diameter size of the second deformable portion is set larger than the outer diameter size of the first deformable portion, and the outer diameter size of the third deformable portion is larger than the outer diameter size of the second deformable portion. And it is set large.

  In the webbing take-up device according to claim 3, the first deforming portion, the second deforming portion, and the third deforming portion are provided integrally, and the outer diameter dimensions thereof are the first deforming portion, the second deforming portion, and the second deforming portion, respectively. It is set larger in the order of the deformation part and the third deformation part. For this reason, the mechanical strength of each of the first deformation part, the second deformation part, and the third deformation part is set by setting the outer diameter dimensions of the first deformation part, the second deformation part, and the third deformation part, respectively. Can be set easily.

  The webbing take-up device according to a fourth aspect is the webbing take-up device according to any one of the first to third aspects, wherein the rotation transmitting unit and the speed detecting unit are integrally provided. .

  In the webbing take-up device according to the fourth aspect, since the rotation transmitting unit and the speed detecting unit are integrally provided, an increase in the number of parts can be suppressed.

  According to the webbing take-up device of the first aspect, the force limiter load can be increased stepwise while suppressing an increase in the size of the webbing take-up device in the axial direction of the take-up shaft.

  According to the webbing take-up device of the second aspect, the degree of freedom in setting the load value of the force limiter load can be improved.

  According to the webbing take-up device of the third aspect, the load value of the force limiter load can be easily set.

  According to the webbing take-up device described in claim 4, an increase in the number of parts can be suppressed, and an increase in cost can be suppressed.

It is the disassembled perspective view seen from the vehicle width direction outer side and the vehicle front-back direction one side which shows the structure of the webbing winding device which concerns on embodiment of this invention. It is sectional drawing which shows the spool, the torsion bar, the 1st pawl, and the 2nd pawl which are used for the webbing winding device shown in FIG. (A) is sectional drawing which shows the state from which the 1st engagement tooth of the 1st pawl used for the webbing winding device shown in Drawing 1 is separated from the external tooth of the 1st gear part of a torsion bar ( FIG. 3 is a sectional view taken along line 3-3 in FIG. (B) is sectional drawing which shows the state in which the 1st engagement tooth of a 1st pawl is meshing | engaged with the external tooth of the 1st gear part of a torsion bar (3-3 sectional view of FIG. 2). (A) is sectional drawing which shows the state from which the 2nd engagement tooth of the 2nd pawl used for the webbing winding device shown in Drawing 1 is separated from the external tooth of the 2nd gear part of a torsion bar ( FIG. 4 is a sectional view taken along line 4-4 in FIG. (B) is sectional drawing which shows the state in which the 2nd engagement tooth of a 2nd pawl is meshing with the external tooth of the 2nd gear part of a torsion bar (4-4 sectional view taken on the line of FIG. 2). (A) is a conceptual diagram showing the rotational speed in the pull-out direction of the spool used in the webbing take-up device shown in FIG. 1, and (B) corresponds to the rotational speed of the spool shown in FIG. 5 (A). It is a conceptual diagram showing the force limiter load added to the performed webbing.

  FIG. 1 shows an exploded perspective view of a webbing take-up device 10 according to an embodiment of the present invention as viewed from the outside in the vehicle width direction and from one side in the vehicle front-rear direction. The outer side is indicated by an arrow OUT, one side in the vehicle front-rear direction is indicated by an arrow LO, and the upper side is indicated by an arrow UP.

  As shown in the figure, the webbing take-up device 10 according to the present embodiment is provided with a frame 12 formed in a substantially U shape in a plan view. The frame 12 is provided with a back plate 12A on the inner side in the vehicle width direction, a leg plate 12B on one side in the vehicle longitudinal direction, and a leg plate 12C on the other side in the vehicle longitudinal direction. The frame 12 is fixed to the vehicle at the back plate 12A, whereby the webbing take-up device 10 is installed in the vehicle.

  In the leg plate 12B and the leg plate 12C, substantially circular arrangement holes 14 and arrangement holes 16 are formed so as to penetrate coaxially, and the arrangement hole 14 and the arrangement hole 16 are opposed to each other. A substantially cylindrical spool 20 is provided between the leg plate 12B (arrangement hole 14) and the leg plate 12C (arrangement hole 16) of the frame 12, and a long webbing 22 is provided on the spool 20 at the base end. It is wound from the side. When the spool 20 is rotated in the winding direction (the direction of arrow A in FIG. 1), the webbing 22 is wound around the spool 20, and the webbing 22 is pulled out from the spool 20, so that the spool 20 is pulled out. It is rotated in the direction of arrow B in FIG.

  As shown in FIGS. 2, 3 (A) and 3 (B), the first accommodating portion 24 that accommodates a first pawl 64 and a first torsion spring 72, which will be described later, on the radially inner side (inside the cylinder) of the spool 20. Is provided. The first accommodating portion 24 is provided with a bottom surface 24 </ b> A, and the bottom surface 24 </ b> A is disposed in a direction orthogonal to the axial direction of the spool 20. The first accommodating portion 24 is provided with a first support portion 26 having a substantially semicircular cross section when viewed from one axial direction side of the spool 20 (the arrow C side in FIG. 2), and above the first support portion 26. , A first recess 28 is provided. The first accommodating portion 24 is provided with a first abutting portion 30 having a substantially semicircular cross section on the opposite side of the first supporting portion 26 from the first recessed portion 28. Protrudes radially inward of the spool 20. Further, the first accommodating portion 24 is provided with a substantially rectangular columnar first locking portion 32 at the lower side, and the first locking portion 32 protrudes from the bottom surface 24 </ b> A toward one side in the axial direction of the spool 20. Has been.

  As shown in FIGS. 2, 4 (A) and 4 (B), on the radially inner side (inside the cylinder) of the spool 20, a second housing portion 34 for housing a second pawl 74 and a second torsion spring 82 which will be described later. Is provided. The second housing portion 34 is provided with a bottom surface 34 </ b> A, and the bottom surface 34 </ b> A is disposed in a direction orthogonal to the axial direction of the spool 20. The second housing part 34 is provided with a second support part 36 having a substantially semicircular cross section when viewed from one axial direction of the spool 20, and a second recess 38 is provided above the second support part 36. It has been. Further, the second accommodating portion 34 is provided with a second abutting portion 40 having a substantially semicircular cross section on the opposite side of the second supporting portion 36 from the second recessed portion 38. Protrudes radially inward of the spool 20. Further, the second housing portion 34 is provided with a substantially rectangular columnar second locking portion 42 below, and the second locking portion 42 projects from the bottom surface 34 </ b> A toward one side in the axial direction of the spool 20. Has been.

  As shown in FIGS. 1 and 2, a substantially shaft-like torsion bar 44 as an energy absorbing member constituting the force limiter mechanism is coaxially inserted on the radially inner side (inside the cylinder) of the spool 20. A substantially cylindrical support shaft portion 46 is provided at one end portion in the axial direction of the torsion bar 44 (the end portion in the direction of arrow C in FIG. 2), and the support shaft portion 46 extends from one end portion in the axial direction of the spool 20. It protrudes and is rotatably supported by a support member (not shown) attached to the leg plate 12B of the frame 12.

  A spline-like tooth 48 as a take-up shaft connecting portion is provided at the other axial end of the torsion bar 44 (the end in the direction of arrow D in FIG. 2). The teeth 48 are fitted to the end of the spool 20 on the leg plate 12C side and are prevented from coming off by the screw 50. Thus, the other axial end of the torsion bar 44 is fixed (coupled) to the spool 20 so as not to rotate relative to the spool 20, and the torsion bar 44 is configured to be rotatable integrally with the spool 20. Further, spline-like teeth 52 as a lock mechanism connecting portion are integrally provided on the other axial side of the support shaft portion 46 of the torsion bar 44 (the arrow D direction side in FIG. 2). The lock gear 84 is fixed (connected) so as not to be relatively rotatable. Further, the tooth 52 is integrally formed with a disk-like flange 52A on one side in the axial direction of the torsion bar 44.

  Between the teeth 48 and the teeth 52 of the torsion bar 44, a substantially cylindrical first gear portion 54 as a first engaging portion is provided. The first gear portion 54 is disposed coaxially with the support shaft portion 46, and external teeth 54 </ b> A are formed on the entire outer periphery of the first gear portion 54. A substantially cylindrical second gear portion 56 as a second engaging portion is provided between the first gear portion 54 and the teeth 52 of the torsion bar 44. The second gear portion 56 is disposed coaxially with the first gear portion 54, and external teeth 56 </ b> A are formed on the entire outer periphery of the second gear portion 56.

  Between the teeth 48 of the torsion bar 44 and the first gear portion 54, a shaft-like first torsional deforming portion 58 as a first deforming portion is stretched, and the first torsionally deforming portion 58 is supported by the support shaft. It is arranged coaxially with the portion 46 and is provided integrally with the teeth 48 and the first gear portion 54. The first torsional deforming portion 58 is configured to be torsionally deformed by applying a torsional load of a predetermined value or more.

  Between the first gear portion 54 and the second gear portion 56 of the torsion bar 44, a shaft-like second torsional deformation portion 60 as a second deformation portion is stretched, and the second torsional deformation portion 60 is The first gear portion 54 and the second gear portion 56 are provided integrally. Further, the second torsional deformable portion 60 is arranged coaxially with the first torsional deformable portion 58, and the outer diameter size of the second torsional deformable portion 60 is larger than the outer diameter size of the first torsional deformable portion 58. It is set large. Thereby, the mechanical strength of the second torsional deformable portion 60 is set to be larger than the mechanical strength of the first torsional deformable portion 58. Therefore, the second torsion deformable portion 60 is configured to be torsionally deformed by applying to the second torsion deformable portion 60 a torsional load larger than the load at which the first torsionally deformable portion 58 is torsionally deformed.

  Between the second gear portion 56 of the torsion bar 44 and the teeth 52, a shaft-like third torsional deformation portion 62 as a third deformation portion is stretched, and the third torsional deformation portion 62 is the second gear. The unit 56 and the teeth 52 are provided integrally. Further, the third torsional deforming part 62 is arranged coaxially with the second torsional deforming part 60, and the outer diameter dimension of the third torsional deforming part 62 is larger than the outer diameter dimension of the second torsional deforming part 60. It is set large. Thereby, the mechanical strength of the third torsional deformable portion 62 is set to be larger than the mechanical strength of the second torsionally deformable portion 60. Therefore, the third torsional deformation part 62 is configured to be capable of being torsionally deformed by applying a torsional load larger than the load at which the second torsional deformation part 60 is torsionally deformed to the third torsional deformation part 62.

  As shown in FIGS. 3A and 3B, the first accommodating portion 24 of the spool 20 is provided with a substantially C-shaped plate-like first pawl 64 as a first rotation transmitting portion. A first shaft portion 66 having a substantially semicircular cross section is provided at a substantially central portion of the first pawl 64, and the first shaft portion 66 is disposed in the first support portion 26 of the spool 20, and The support portion 26 is rotatably supported.

  A first weight portion 68 having a substantially rectangular cross section as a first speed detecting portion is integrally provided at one end portion of the first pawl 64, and the first weight portion 68 is placed in the first recess 28 of the spool 20. Has been placed. A first engagement tooth 70 is provided at the other end of the first pawl 64, and the first engagement tooth 70 corresponds to the external tooth 54A of the first gear portion 54 of the torsion bar 44 described above. .

  A first torsion spring 72 is disposed in the first housing portion 24. One end of the first torsion spring 72 is locked to the first engaging tooth 70 described above, and the other end is locked between the first locking portion 32 and the inner peripheral surface of the spool 20. The first torsion spring 72 biases the first pawl 64 around the axis of the first shaft portion 66 in the winding direction (direction of arrow F in FIG. 3B). Accordingly, the first pawl 64 is in contact with the first contact portion 30 (the state shown in FIG. 3A). The first engagement tooth 70 is configured such that the first pawl 64 is drawn around the axis of the first shaft portion 66 (the direction of arrow E in FIG. 3A is referred to as “first lock activation direction”). By rotating, it approaches the external teeth 54A of the first gear portion 54 and meshes with the external teeth 54A. Thereby, the rotational force in the pull-out direction of the spool 20 is transmitted to the torsion bar 44 through the first pawl 64 (the state shown in FIG. 3B). When the first pawl 64 rotates from this state in the winding direction (the direction of arrow F in FIG. 3B), the first engagement teeth 70 are separated from the external teeth 54A of the first gear portion 54. It is configured.

  As shown in FIGS. 4A and 4B, the second accommodating portion 34 of the spool 20 is provided with a substantially C-shaped plate-like second pawl 74 as a second rotation transmitting portion. A second shaft portion 76 having a substantially semicircular cross section is provided at a substantially central portion of the second pawl 74, and the second shaft portion 76 is disposed in the second support portion 36 of the spool 20. 2 It is supported by the support part 36 so that rotation is possible.

  A second weight portion 78 having a substantially rectangular cross section as a second speed detecting portion is integrally provided at one end portion of the second pawl 74, and the second weight portion 78 is placed in the second recess 38 of the spool 20. Has been placed. Further, the size of the outer shape of the second weight portion 78 is set smaller than the size of the outer shape of the first weight portion 68. For this reason, the weight of the second weight portion 78 is set smaller than the weight of the first weight portion 68. Second engagement teeth 80 are provided at the other end of the second pawl 74, and the second engagement teeth 80 correspond to the external teeth 56A of the second gear portion 56 of the torsion bar 44 described above. .

  A second torsion spring 82 is disposed in the second housing portion 34. One end of the second torsion spring 82 is locked to the second engaging tooth 80 described above, and the other end is locked between the second locking portion 42 and the inner peripheral surface of the spool 20. The second torsion spring 82 biases the second pawl 74 around the axis of the second shaft portion 76 in the winding direction (the direction indicated by the arrow H in FIG. 4B). Thus, the second pawl 74 is in contact with the second contact portion 40 (the state shown in FIG. 4A). The urging force of the second torsion spring 82 is set to be the same as the urging force of the first torsion spring 72. In the second engagement tooth 80, the second pawl 74 is pulled out around the axis of the second shaft portion 76 (in the direction of arrow G in FIG. 4A), and this direction is referred to as the “second lock activation direction”. By rotating, it approaches the external teeth 56A of the second gear portion 56 and meshes with the external teeth 56A. Thereby, the rotational force in the pull-out direction of the spool 20 is transmitted to the torsion bar 44 through the second pawl 74 (the state shown in FIG. 4B). In this state, when the second pawl 74 rotates in the winding direction (the direction indicated by the arrow H in FIG. 4B), the second engagement teeth 80 are separated from the outer teeth 56A of the second gear portion 56. It is configured as follows.

  As shown in FIGS. 1 and 2, a substantially disc-shaped lock gear 84 constituting a lock mechanism is provided on the leg plate 12 </ b> B side (one end side) of the spool 20. A fitting hole 84A having a spline cross section is formed through the central portion of the lock gear 84, and the lock gear 84 rotates relative to the torsion bar 44 by fitting the teeth 52 of the torsion bar 44 into the fitting hole 84A. It is impossible (fixed). As a result, the lock gear 84 is configured to rotate integrally with the torsion bar 44. Further, ratchet teeth 84B (external teeth) are formed on the entire outer periphery of the lock gear 84.

  An urging mechanism (not shown) as urging means is provided on the outer side of the leg plate 12C of the frame 12, and the urging mechanism is connected to the spool 20 and applies an urging force to the spool 20 in the winding direction. It is acting.

  As shown in FIG. 1, the leg plate 12 </ b> B of the frame 12 is an element grasped as a substantially plate-like lock plate 86 (in a broad sense, a “regulator member”) in the vicinity of the arrangement hole 14. ) Is rotatably supported, and the lock plate 86 is formed with lock teeth 86A. The lock plate 86 is in communication with a restriction mechanism (not shown) (which is an element grasped as “regulation means” in a broad sense). When the webbing 22 is suddenly drawn and the spool 20 rotates at a predetermined speed or more in the drawing direction or when the vehicle is suddenly decelerated (hereinafter referred to as “the emergency of the vehicle”), the restriction mechanism is activated, The lock plate 86 is rotated, and the lock teeth 86A are engaged (engaged) with the ratchet teeth 84B of the lock gear 84. As a result, rotation of the lock gear 84 in the pull-out direction is restricted (blocked), and rotation of the spool 20 in the pull-out direction is restricted (rotation in the winding direction of the spool 20 is allowed).

  Here, when the spool 20 rotates in the pull-out direction at a first engagement speed (a speed higher than the predetermined speed described above) as the first speed, the centrifugal force acting on the first weight portion 68 of the first pawl 64 is increased. Due to the force, the first pawl 64 is rotated in the first lock starting direction relative to the spool 20 against the urging force of the first torsion spring 72. As a result, the first engagement teeth 70 of the first pawl 64 approach the outer teeth 54 </ b> A of the torsion bar 44 and mesh with each other.

  In this state, when the rotation speed of the spool 20 in the pull-out direction becomes equal to or lower than a first release speed (a speed higher than a predetermined speed and a speed lower than the first engagement speed speed), the first pawl 64 is By the urging force of the torsion spring 72, the torsion spring 72 is rotated in the winding direction to be separated from the external teeth 54A. Thereby, the meshing between the first engagement teeth 70 of the first pawl 64 and the external teeth 54A of the torsion bar 44 is released. The first release speed is slower than the first engagement speed because the first engagement teeth 70 of the first pawl 64 mesh with the external teeth 54A of the torsion bar 44. This is because a resistance force acts between 70 and the external teeth 54A.

  Further, when the spool 20 rotates in the pull-out direction at a second engagement speed (speed faster than the first engagement speed) as the second speed, the centrifugal force acting on the second weight portion 78 of the second pawl 74 is increased. Due to the force, the second pawl 74 is rotated in the second lock activation direction relative to the spool 20 against the urging force of the second torsion spring 82. As a result, the second engagement teeth 80 of the second pawl 74 approach and engage with the external teeth 56 </ b> A of the torsion bar 44.

  In this state, when the rotation speed of the spool 20 in the pull-out direction becomes equal to or lower than the second release speed (speed higher than the first engagement speed and lower than the second engagement speed), the second pawl 74 is The second torsion spring 82 is rotated in the winding direction by the urging force of the second torsion spring 82 to be separated from the external teeth 56A. Thereby, the meshing between the second engaging teeth 80 of the second pawl 74 and the external teeth 56A of the torsion bar 44 is released. Note that the second release speed is slower than the second engagement speed because the second engagement teeth 80 of the second pawl 74 mesh with the external teeth 56A of the torsion bar 44 as described above. This is because a resistance force acts between the second engagement teeth 80 and the external teeth 56A.

  Next, the operation of the present embodiment will be described.

  In the webbing take-up device 10 configured as described above, when the webbing 22 is mounted on an occupant seated on a vehicle seat, the urging mechanism causes the urging mechanism to act on the spool 20 in the take-up direction. The slack is removed.

  First, in the event of an emergency of the vehicle (when the webbing 22 is abruptly pulled and the spool 20 rotates at a predetermined speed or more in the pulling direction or when the vehicle suddenly decelerates), the spool 20 moves in the pulling direction from the predetermined speed to the first engagement. A case of rotating at a combined speed will be described. In this case, for example, the weight of the seated occupant is light or the vehicle collides at a low speed.

  In the event of an emergency of the vehicle, the locking mechanism 86 is operated so that the lock teeth 86A of the lock plate 86 are engaged with the ratchet teeth 84B of the lock gear 84. As a result, rotation of the lock gear 84 in the pull-out direction is restricted, and rotation of the spool 20 in the pull-out direction is restricted. For this reason, pulling out the webbing 22 from the spool 20 is restricted, and the webbing 22 restrains the occupant. At this time, the load applied to the webbing 22 is gradually increased by the inertial energy acting on the occupant.

  Further, in a state where the withdrawal of the webbing 22 is restricted, a torsion load is applied to the torsion bar 44 via the webbing 22 and the spool 20 by the inertial energy acting on the occupant. Since the mechanical strength of the first torsion deforming portion 58 of the torsion bar 44 is set lower than the mechanical strength of the second torsion deforming portion 60 and the third torsion deforming portion 62, this torsion load is the first torsion deforming portion 58. When the mechanical strength of the deformation portion 58 is exceeded, the first torsion deformation portion 58 mainly undergoes torsional deformation. For this reason, the spool 20 rotates relative to the lock gear 84 in the pull-out direction. Thereby, the webbing 22 is pulled out and the load (energy) acting on the occupant is absorbed from the webbing 22. That is, while the torsional load accompanying the torsional deformation of the first torsional deforming portion 58 of the torsion bar 44 acts on the occupant as the force limiter load via the webbing 22, the spool 20 is rotated in the pull-out direction with respect to the lock gear 84, Energy absorption is achieved. The load value of the force limiter load at this time is F1 (see the alternate long and short dash line shown in FIG. 5B).

  Next, a case where the spool 20 rotates in the pull-out direction at the first engagement speed to the second engagement speed in the event of an emergency of the vehicle will be described. This is the case, for example, when the seated occupant has an adult standard physique or when the vehicle collides at medium speed.

  As described above, when the vehicle is in an emergency, the restriction mechanism is operated, whereby the rotation of the lock gear 84 in the pull-out direction is restricted, and the rotation of the spool 20 in the pull-out direction is restricted. For this reason, the webbing 22 is pulled by the inertial energy acting on the occupant, and the load applied to the webbing 22 gradually increases.

  Further, when the torsional load applied to the torsion bar 44 via the webbing 22 and the spool 20 by the inertial energy acting on the occupant exceeds the mechanical strength of the first torsional deforming part 58, the first torsional deforming part 58 is twisted. Deform. Thereby, the load value of the force limiter load becomes F1 (see the two-dot chain line shown in FIG. 5B).

  Further, when the rotation speed of the spool 20 in the pulling direction becomes equal to or higher than the first engagement speed, the first pawl 64 is attached to the first torsion spring 72 by the centrifugal force acting on the first weight portion 68 of the first pawl 64. It is rotated in the first lock activation direction relative to the spool 20 against the force. As a result, the first engagement teeth 70 of the first pawl 64 approach and engage with the external teeth 54 </ b> A of the first gear portion 54 of the torsion bar 44.

  At this time, the rotational force in the pulling-out direction of the spool 20 is transmitted to the first gear portion 54 of the torsion bar 44 by the first pawl 64, and the rotational force is transmitted to the second torsional deforming portion 60 and the second torsional portion 44 of the torsion bar 44. This is transmitted to the lock gear 84 via the three twist deformable portion 62. Since the mechanical strength of the second torsion deformable portion 60 is set to be larger than the mechanical strength of the first torsion deformable portion 58, the torsional load applied to the torsion bar 44 is Until the mechanical strength is exceeded, the second torsional deforming portion 60 does not twist and deform, so the load applied to the webbing 22 gradually increases.

  Further, when the torsional load applied to the torsion bar 44 becomes equal to or higher than the mechanical strength of the second torsion deforming part 60, the second torsion deforming part 60 of the torsion bar 44 is mainly torsionally deformed, and the webbing 22 is pulled out. Thus, the load (energy) acting on the occupant is absorbed from the webbing 22. The load value of the force limiter load applied to the webbing 22 at this time is F2 (see the two-dot chain line shown in FIG. 5B).

  When the speed of the webbing 22 in the pull-out direction decreases to the first release speed, the first pawl 64 is rotated in the winding direction by the urging force of the first torsion spring 72, and the first gear of the torsion bar 44 is rotated. It is separated from the external teeth 54A of the portion 54. For this reason, the meshing between the first engagement teeth 70 of the first pawl 64 and the external teeth 54A of the torsion bar 44 is released. As a result, the load value of the force limiter load applied to the webbing 22 decreases from F2 to F1, and the webbing 22 is pulled out in this state, and the load (energy) acting on the occupant is absorbed from the webbing 22.

  Thus, the load value of the force limiter load applied to the webbing 22 can be increased from F1 to F2 according to the rotational speed in the pulling direction of the spool 20, and the load value of the force limiter load is changed from F2 to F1. Can be lowered.

  Next, the case where the spool 20 rotates in the pull-out direction at the second engagement speed or more in an emergency of the vehicle will be described. In this case, for example, when the weight of the seated occupant is heavy or when the vehicle collides at a high speed.

  As described above, when the regulation mechanism is operated in the event of an emergency of the vehicle, the rotation of the lock gear 84 in the pull-out direction is restricted, and the rotation of the spool 20 in the pull-out direction is restricted. For this reason, the webbing 22 is pulled by the inertial energy acting on the occupant, and the load applied to the webbing 22 gradually increases.

  Further, when the torsional load applied to the torsion bar 44 via the webbing 22 and the spool 20 by the inertial energy acting on the occupant exceeds the mechanical strength of the first torsional deforming part 58, the first torsional deforming part 58 is twisted. Deform. As a result, the load value of the force limiter load applied to the webbing 22 becomes F1 (see the solid line shown in FIG. 5B).

  Further, when the rotation speed of the spool 20 in the pulling direction becomes equal to or higher than the first engagement speed, the first pawl 64 is attached to the first torsion spring 72 by the centrifugal force acting on the first weight portion 68 of the first pawl 64. It is rotated in the first lock activation direction relative to the spool 20 against the force. As a result, the first engagement teeth 70 of the first pawl 64 approach the outer teeth 54 </ b> A of the torsion bar 44 and mesh with each other. At this time, the rotational force in the pulling-out direction of the spool 20 is transmitted to the first gear portion 54 of the torsion bar 44 by the first pawl 64, and the rotational force is transmitted to the second torsional deforming portion 60 and the second torsional portion 44 of the torsion bar 44. This is transmitted to the lock gear 84 via the three twist deformable portion 62. Since the mechanical strength of the second torsion deformable portion 60 is set to be larger than the mechanical strength of the first torsion deformable portion 58, the torsional load applied to the torsion bar 44 is Until the mechanical strength is exceeded, the second torsional deforming portion 60 does not twist and deform, so that the load applied to the webbing 22 gradually increases.

  In this state, when the torsional load applied to the torsion bar 44 exceeds the mechanical strength of the second torsion deformable portion 60, the second torsion deformable portion 60 is mainly torsionally deformed, and the webbing 22 is pulled out, so that the webbing The load (energy) acting on the occupant from 22 is absorbed. The force limiter load applied to the webbing 22 at this time is F2 (see the solid line shown in FIG. 5B).

  Further, when the rotational speed of the spool 20 in the pull-out direction becomes equal to or higher than the second engagement speed, the second pawl 74 is attached to the second torsion spring 82 by the centrifugal force acting on the second weight portion 78 of the second pawl 74. It is rotated in the second lock activation direction relative to the spool 20 against the force. As a result, the second engagement teeth 80 of the second pawl 74 approach and engage with the external teeth 56 </ b> A of the second gear portion 56 of the torsion bar 44. At this time, the rotational force in the pull-out direction of the spool 20 is transmitted to the second gear portion 56 of the torsion bar 44 by the second pawl 74, and the rotational force is transmitted via the third torsional deforming portion 62 of the torsion bar 44. Is transmitted to the lock gear 84. Since the mechanical strength of the third torsional deformation portion 62 is set to be larger than the mechanical strength of the second torsional deformation portion 60, the torsional load applied to the torsion bar 44 is Until the mechanical strength is exceeded, the third torsional deforming portion 62 does not twist and deform, so the load applied to the webbing 22 gradually increases.

  In this state, when the torsional load applied to the torsion bar 44 becomes equal to or higher than the mechanical strength of the third torsion deforming portion 62, the third torsion deforming portion 62 of the torsion bar 44 is torsionally deformed and the webbing 22 is pulled out. The load (energy) acting on the occupant is absorbed from the webbing 22. The load value of the force limiter load applied to the webbing 22 at this time is F3 (see the solid line shown in FIG. 5B).

  When the rotational speed of the webbing 22 in the pull-out direction becomes equal to or lower than the second release speed, the second pawl 74 is rotated in the winding direction by the urging force of the first torsion spring 72, and the torsion bar 44 The two gear portions 56 are separated from the external teeth 56A. For this reason, the meshing between the second engagement teeth 80 of the second pawl 74 and the external teeth 56A of the torsion bar 44 is released. Thereby, the load value of the force limiter load decreases from F3 to F2, and the webbing 22 is pulled out in this state, and the load (energy) acting on the occupant is absorbed from the webbing 22.

  Further, when the rotational speed of the webbing 22 in the pull-out direction becomes equal to or less than the first release speed, the first pawl 64 is rotated in the winding direction by the urging force of the first torsion spring 72, and the torsion bar 44 The first gear part 54 is separated from the external teeth 54A. For this reason, the meshing between the first engagement teeth 70 of the first pawl 64 and the external teeth 54A of the torsion bar 44 is released. Thereby, the load value of the force limiter load decreases from F2 to F1, and the webbing 22 is pulled out in this state, and the load (energy) acting on the occupant is absorbed from the webbing 22.

  As described above, the load value of the force limiter load applied to the webbing 22 can be increased from F1 to F2 and from F2 to F3 according to the rotational speed of the spool 20 in the pull-out direction. The force limiter load value can be lowered from F3 to F2 and from F2 to F1.

  Further, when the spool 20 rotates in the pull-out direction at a high speed, the engagement of the first engagement teeth 70 of the first pawl 64 with the external teeth 54A of the torsion bar 44 and the second engagement teeth of the second pawl 74 are performed. The meshing of the 80 torsion bars 44 with the external teeth 56A is performed substantially simultaneously. Thereby, for example, the load value of the force limiter load can be increased from F1 to F3 at a stretch.

  Here, the spool 20 is provided with a first pawl 64 and a second pawl 74, and the outer teeth 54 </ b> A and the outer teeth 56 </ b> A of the torsion bar 44 provided on the radially inner side (in the cylinder) of the spool 20, respectively. The first engagement teeth 70 of the first pawl 64 and the second engagement teeth 80 of the second pawl 74 are meshed. Therefore, the first pawl 64 and the second pawl 74 are provided on the radially inner side (inside the cylinder) of the spool 20, and the outer teeth 54 </ b> A and the outer teeth 56 </ b> A of the torsion bar 44 are respectively provided according to the rotational speed of the spool 20. The first engagement teeth 70 of the first pawl 64 and the second engagement teeth 80 of the second pawl 74 can be engaged with each other. As a result, the force limiter load can be increased in stages while suppressing an increase in the size of the webbing take-up device 10 in the axial direction of the spool 20.

  As described above, the force limiter load value is any one of F1, F2, and F3 depending on the rotational speed of the spool 20 in the pull-out direction. Therefore, the load value of the force limiter load can be set in three stages according to the rotation speed of the spool 20. Thereby, the setting freedom degree of the force value of a force limiter load can be improved.

  Further, the first torsional deformation part 58, the second torsional deformation part 60, and the third torsional deformation part 62 are integrally provided in a shaft shape, and the outer diameter of the second torsional deformation part 60 is the first torsional deformation. The outer diameter of the third torsion deformable portion 62 is set to be larger than the outer diameter of the second torsion deformable portion 60. For this reason, by setting the outer diameter dimensions of the first torsional deformation part 58, the second torsional deformation part 60, and the third torsional deformation part 62, respectively, the first torsional deformation part 58, the second torsional deformation part 60, and Each mechanical strength of the third torsional deformable portion 62 can be easily set. Thereby, the load value of the force limiter load can be easily set.

  Further, the first weight portion 68 is integrally provided on the first pawl 64, and the second weight portion 78 is integrally provided on the second pawl 74. For this reason, an increase in the number of parts can be suppressed, and an increase in cost can be suppressed.

  In the present embodiment, the load value of the force limiter load is set in three stages, but the load value of the force limiter load may be set in four stages or more. For example, when the load value of the force limiter load is set to four levels, the torsion bar 44 is provided with four torsionally deformed portions having different mechanical strengths. Moreover, a gear part is provided between each twist deformation part. Furthermore, pawls that engage with the respective gear portions may be provided in accordance with the rotational speed of the spool 20 in the pull-out direction.

  Further, in the present embodiment, the first torsional deformation part 58, the second torsional deformation part 60, and the third torsional deformation part 62 are provided integrally, and the first torsional deformation part 58 and the second torsional deformation part 60 are provided. The mechanical strength is set by setting the outer diameter of each of the third torsional deformable portions 62. Instead, the first torsional deformation part 58, the second torsional deformation part 60, and the third torsional deformation part 62 are configured as separate members, and the first torsional deformation part 58, the second torsional deformation part 60, and You may set the mechanical strength of the 3rd twist deformation part 62. FIG.

  Further, in the present embodiment, the first weight portion 68 is integrally provided on the first pawl 64, and the second weight portion 78 is integrally provided on the second pawl 74. Alternatively, the first weight portion 68 and the second weight portion 78 may be provided separately from the first pawl 64 and the second pawl 74, respectively. In this case, for example, the first weight portion 68 is configured to be disengaged from the first pawl 64 in accordance with the rotational speed of the spool 20 in the pull-out direction, and the first weight portion 68 is engaged with the first pawl 64. By combining, the first pawl 64 may mesh with the external teeth 54 </ b> A of the torsion bar 44.

  In the present embodiment, the weight of the first weight portion 68 of the first pawl 64 is set to be larger than the weight of the second weight portion 78 of the second pawl 74, and the spool 20 is in the first engagement. The first pawl 64 meshes with the external teeth 54A of the torsion bar 44 when the speed exceeds the speed, and the second pawl 74 meshes with the external teeth 56A of the torsion bar 44 when the spool 20 exceeds the second engagement speed. Instead, the weight of the first weight portion 68 and the weight of the second weight portion 78 are set to be the same, and the urging force of the first torsion spring 72 is set smaller than the urging force of the second torsion spring. May be. Accordingly, the first pawl 64 meshes with the external teeth 54A of the torsion bar 44 when the spool 20 is higher than the first engagement speed, and the second pawl 74 is engaged with the torsion bar when the spool 20 is higher than the second engagement speed. 44 external teeth 56A.

10 Webbing take-up device 20 Spool take-up shaft 44 Torsion bar (energy absorbing member)
48 teeth (winding shaft connecting part)
52 teeth (lock mechanism connecting part)
54 1st gear part (1st engaging part)
56 Second gear part (second engaging part)
58 First torsional deformation part (first deformation part)
60 Second torsion deformation part (second deformation part)
62 Third torsional deformation part (third deformation part)
64 1st pawl (1st rotation transmission part)
68 1st weight part (1st speed detection part)
74 2nd pawl (2nd rotation transmission part)
78 Second weight part (second speed detection part)
84 Lock gear (lock mechanism)

Claims (4)

A winding shaft that is rotated in the pull-out direction by pulling out the webbing for occupant restraint,
Provided at one axial end of the take-up shaft, preventing rotation of the take-up shaft in the pull-out direction during vehicle sudden deceleration and at least one of when the take-up shaft suddenly rotates in the pull-out direction A locking mechanism,
A lock mechanism connecting portion provided coaxially with the take-up shaft on the radially inner side of the take-up shaft and connected to the lock mechanism on one end side in the axial direction and the take-up shaft on the other end side in the axial direction. A take-up shaft connecting portion connected to be integrally rotatable, and an engaging portion between the lock mechanism connecting portion and the take-up shaft connecting portion. An energy absorbing member in which the mechanical strength of the portion is set larger than the mechanical strength of the portion on the other end side in the axial direction from the engagement portion;
Rotation that is provided on the winding shaft, is configured to be able to contact and separate from the engaging portion, and transmits rotation of the winding shaft to the energy absorbing member by engaging with the engaging portion. A transmission part;
The winding shaft is provided in the winding shaft and includes a weight portion. The winding shaft rotates in the pull-out direction at a speed equal to or higher than the first speed, and is rotated radially outward of the winding shaft by centrifugal force. A rotation speed detecting portion for rotating the rotation transmitting portion radially inward of the winding shaft and engaging the engaging portion;
A webbing take-up device comprising: The engagement portion includes a first engagement portion, and a second engagement portion disposed between the first engagement portion and the lock mechanism coupling portion,
The rotation transmission unit includes a first rotation transmission unit that engages with the first engagement unit, and a second rotation transmission unit that engages with the second engagement unit,
The speed detection unit includes a first speed detection unit that engages the first rotation transmission unit with the first engagement unit when the winding shaft rotates in the pull-out direction at the first speed or more, and the winding A second speed detection unit that engages the second rotation transmission unit with the second engagement unit by rotating the take-up shaft at a second speed higher than the first speed in the pull-out direction;
The energy absorbing member is provided between a first deforming portion provided between the winding shaft connecting portion and the first engaging portion, and between the first engaging portion and the second engaging portion. And a third deformation portion provided between the second engagement portion and the lock mechanism connecting portion, and the mechanical strength of the second deformation portion is the first. 2. The webbing winding according to claim 1, wherein the webbing winding is set higher than the mechanical strength of the deformed portion and the mechanical strength of the third deformed portion is set higher than the mechanical strength of the second deformed portion. Taking device.   The first deformable portion, the second deformable portion, and the third deformable portion are integrally provided in a shaft shape, and the outer diameter size of the second deformable portion is larger than the outer diameter size of the first deformable portion. 3. The webbing retractor according to claim 2, wherein the webbing take-up device is set to be large and has an outer diameter dimension of the third deformable portion larger than an outer diameter dimension of the second deformable portion.   The webbing take-up device according to any one of claims 1 to 3, wherein the rotation transmission unit and the speed detection unit are integrally provided.

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