JP2013043522A - Webbing winding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a webbing winding device in which an error in rotation speed of a spool from occurrence of deformation in a torsion shaft to the end of the transformation is reduced and further, assembly work is facilitated.SOLUTION: When a spool 18 is relatively rotated in an unwinding direction with respect to a sun gear 96 formed in a torsion shaft 30, a carrier 112 is rotated in the unwinding direction in a reduction ratio corresponding to the number of teeth of a gear hole 94 formed in the spool 18 and the number of teeth in the sun gear 96. Since there is a speed difference between the spool 18 and the carrier 112, when the spool 18 is relatively rotated in the unwinding direction just for a rotation speed which is preset based on the reduction ratio, a spool-side abutting part 134 is abutted on a carrier-side abutting part 132 formed in the carrier 112, any more rotation of the spool 18 in the unwinding direction is regulated, and the torsion shaft 30 is twisted just for the preset rotation speed.

Description

  The present invention relates to a webbing retractor that constitutes a seat belt device of a vehicle.

  In the seat belt retractor disclosed in Patent Document 1 below, a male screw is formed on the outer periphery of a column of the pawl holder, and a female screw of a stopper member is screwed into the male screw of the column. The stopper portion is restricted from rotating relative to the spool. For this reason, when the spool rotates in the pull-out direction in a state where the rotation of the pawl holder in the pull-out direction is restricted, the stopper member in which the female screw is engaged with the male screw of the column moves in the axial direction of the column (that is, the pawl holder) It abuts against the back surface of the flange portion of the pawl holder. As described above, the stopper member abuts against the back surface of the flange portion, so that the rotation in the pull-out direction of the spool is restricted, and further torsional deformation of the torsion bar as the energy absorbing means is restricted. .

Japanese Patent Laid-Open No. 11-59330

  By the way, in order to form a male screw on a column of a metal pawl holder, for example, rolling molding is used. The male screw formed by such molding is male screwed around the center axis of the pawl holder with respect to the pawl holder itself. There is an error in the formation position (start point position and end point position of the male screw). For this reason, an error also occurs in the number of rotations of the stopper required until the stopper member comes into contact with the back surface of the flange portion. After selecting the pawl holder with male threads so that such errors do not occur, the stopper's female thread is assembled to the male thread of the column, or the stopper member around the center axis of the pawl holder is strictly aligned, etc. Assembling work was complicated.

  In view of the above facts, the present invention can provide a webbing take-up device that reduces an error in the number of rotations of the spool from when the torsion shaft is deformed to when the deformation is finished and that is easy to assemble. Is the purpose.

  A webbing take-up device according to a first aspect of the present invention comprises a spool that rotates in the take-up direction to take up the webbing from its longitudinal base end side, and is provided inside the spool and is provided with a shaft of the spool. A torsion shaft connected to the spool in a state in which relative rotation with respect to the spool is restricted on the other end side relative to one end in the direction, and a state in which relative rotation with respect to the torsion shaft is provided on one end side in the axial direction of the spool The lock base connected to the torsion shaft is activated when the vehicle is rapidly decelerated or the rotational acceleration in the pull-out direction opposite to the winding direction of the spool is greater than or equal to a predetermined magnitude. A lock mechanism that restricts rotation of the spool in the pull-out direction, and a central axis of the spool provided on one axial end of the spool. A rotating body that is rotatable about an axis having the same direction as an axial direction, and the relative rotation of the spool that is operated by a relative rotation in the pull-out direction of the spool with respect to the torsion shaft on one axial end side of the spool. Speed change means for transmitting the speed to the rotating body and rotating the rotating body in the pull-out direction, and one of the spool and the rotating body having the slower rotation speed in the pull-out direction when the speed change means is in operation. And when the relative rotation of the spool reaches a predetermined number of rotations, the spool and the rotating body interfere with the faster rotation speed in the pull-out direction in the operating state of the transmission means. And restricting means for restricting the slower rotation in the pull-out direction.

  In the webbing take-up device according to the first aspect of the present invention, when the vehicle is suddenly decelerated or the rotational acceleration of the spool in the pull-out direction exceeds a predetermined level, the lock mechanism is activated, Restricts rotation of the lock base in the pull-out direction. The lock base is connected to the torsion shaft in a state where relative rotation with respect to the torsion shaft is restricted at one axial end side of the spool. Further, the torsion shaft is connected in a state in which relative rotation with respect to the spool is restricted on the other end side with respect to one end in the axial direction of the spool.

  That is, the lock base is connected to the spool via the torsion shaft in a state where the relative rotation with respect to the spool is restricted. For this reason, the rotation of the lock base in the pull-out direction is restricted, whereby the rotation of the spool in the pull-out direction is restricted, and the webbing withdrawal from the spool is restricted. Thereby, for example, the body of an occupant who intends to move inertially forward of the vehicle at the time of sudden deceleration of the vehicle can be effectively restrained by webbing.

  The body of an occupant who intends to move inertially toward the front of the vehicle tries to rotate the spool in the pull-out direction via the webbing. When the rotational force applied to the spool in the pull-out direction exceeds the mechanical strength of the torsion shaft, the other end is in the pull-out direction with respect to one end side of the torsion shaft that is restricted from rotating in the pull-out direction via the lock base. Rotation, which causes deformation in the torsion shaft. The webbing is pulled out from the spool by a length corresponding to the rotation amount on the other end side with respect to the one end side of the torsion shaft, and the occupant's body can move inertially forward by a distance corresponding to the pulling amount of the webbing. Further, a part of the force of the occupant's body trying to move inertial pulling the webbing to rotate the spool in the pull-out direction is subjected to the deformation of the torsion shaft and absorbed.

  By the way, when deformation occurs in the torsion shaft in this way, the spool rotates in the pull-out direction with respect to one axial end side of the torsion shaft whose rotation in the pull-out direction is regulated via the lock base. When the relative rotation in the pulling-out direction of the spool with respect to the one axial end side of the torsion shaft occurs in this way, the transmission means is operated. The speed change means shifts the relative rotational speed in the pull-out direction of the spool with respect to the one axial end side of the torsion shaft and transmits it to a rotating body provided on one axial end side of the spool. The rotating body to which the rotation in the pull-out direction of the spool is transmitted by the transmission means rotates in the pull-out direction around an axis whose axial direction is the same direction as the central axis of the spool.

  As described above, the rotation of the spool is transmitted to the rotating body while being shifted by the speed change means, and therefore, a speed difference occurs between the spool and the rotating body. Of the spool and the rotating body, the one with the slower rotation speed is provided with a regulating means, and when the relative rotation of the spool with respect to the torsion shaft reaches a predetermined number of rotations, the rotation speed of the spool and the rotating body is higher. Then, the restricting means interferes to restrict the rotation in the pull-out direction with the higher rotation speed.

  Since the rotation of the spool is transmitted to the rotating body by the speed change means, and thus the rotating body rotates, the rotation of one of the spool and the rotating body is restricted, and the other rotation is also restricted. That is, by restricting the rotation of the spool and the rotating body in the pull-out direction with the higher rotation speed by the restricting means, further relative rotation of the spool with respect to the torsion shaft is restricted, and the webbing is drawn from the spool. Be regulated.

  Thus, in the webbing take-up device according to the present invention, the relative rotation speed of the spool with respect to the torsion shaft after the relative rotation of the spool with respect to the torsion shaft is started is restricted by the speed ratio of the transmission means. Determined by. For this reason, the relative rotational position of the rotating body with respect to the spool before the relative rotation is started, that is, the initial position of the rotating body is the rotating body in a state where the relative rotation of the rotating body with respect to the spool is restricted by the restricting means. Can be easily set from the rotational position of the gear and the gear ratio of the transmission means, and there is little error in the relative rotational speed from the initial position until the relative rotation is restricted.

  Further, as described above, since the initial position of the rotating body can be easily set, the rotating body or the like can be easily assembled with a small error.

  The webbing take-up device according to a second aspect of the present invention is the webbing take-up device according to the first aspect, wherein the rotating body is arranged inside the spool at one axial end side of the spool.

  In the webbing take-up device according to the second aspect of the present invention, since the rotating body is disposed inside the spool at one axial end side of the spool, the distance between the spool and the rotating body can be shortened. For this reason, even if it is the structure which provides a control means in any of a spool and a rotary body, even if it does not enlarge a control means, it can be made to interfere with the one where a rotational speed is quick among a spool and a rotary body.

  A webbing take-up device according to a third aspect of the present invention is the webbing take-up device according to the first or second aspect of the present invention, wherein the spool has a radius of rotation of the spool at one end side in the axial direction of the spool relative to the center axis of the spool. A spool-side contact portion is formed on the outer side in the direction, and the rotating body rotates in a state in which the relative rotation in the pull-out direction of the spool with respect to at least one axial end side of the torsion shaft reaches a predetermined rotation speed. A rotating body-side contact portion that faces the spool-side contact portion in the circumferential direction is formed on the rotating body, and any one of the spool-side contact portion and the rotating body-side contact portion serves as the restricting means.

  In the webbing take-up device according to the third aspect of the present invention, a spool-side contact portion is formed on one end side in the axial direction of the spool. The spool side contact portion is formed on the outer side in the rotational radius direction of the spool with respect to the center axis of the spool. For this reason, when the spool rotates, the spool-side contact portion rotates around the center axis of the spool.

  On the other hand, a rotating body side contact portion is formed on the rotating body. The rotating body side abutting portion is opposed to the spool side abutting portion in the circumferential direction of the rotating body in a state where the relative rotation in the pull-out direction of the spool with respect to at least one axial end side of the torsion shaft has reached a predetermined rotational speed To do.

  One of the spool-side abutting portion and the rotating body-side abutting portion serves as a restricting means, and the other of the spool-side abutting portion and the rotating-body-side abutting portion abuts, thereby restricting the rotation in the other drawing direction. As a result, the rotation of the spool in the pull-out direction is restricted.

  A webbing retractor according to a fourth aspect of the present invention is the webbing retractor according to any one of the first to third aspects, wherein the internal gear is formed on the inner peripheral portion of the spool; The transmission means includes a transmission gear that meshes with the internal gear and rotates by relative rotation of the spool in the pull-out direction with respect to the torsion shaft to shift the rotation of the internal gear. .

  In the webbing take-up device according to the fourth aspect of the present invention, an internal gear is formed on the inner peripheral portion of the spool. The internal gear is engaged with the transmission gear. When the spool rotates in the pull-out direction with respect to the torsion shaft, the rotation of the internal gear is transmitted to the transmission gear, which is different from the rotation of the internal gear, that is, the rotation of the spool. The transmission gear is transmitted at speed. Thereby, the rotation of the spool is changed.

  Thus, in the webbing according to the present invention, the speed change means is constituted by a gear train including the internal gear and the transmission gear. Therefore, it can be easily set based on the gear ratio and the number of gear teeth constituting the gear train, and there is little variation (error) in the gear ratio. Further, since the transmission means is constituted by a gear train, the assembly of the transmission means is the assembly of each gear constituting the gear train, and the assembly work is easy and the occurrence of errors is small.

  In the present invention, the gear train constituting the speed change means is not particularly limited to the detailed mode as long as it includes the internal gear and the transmission gear. Therefore, the configuration may be such that the external transmission gear is engaged with the inside of the internal gear, or a planetary gear train having a transmission gear as a planetary gear, a hypocycloid reduction mechanism, or the like.

  A webbing take-up device according to a fifth aspect of the present invention is the planetary gear according to the fourth aspect of the present invention, comprising a planetary gear meshing with the internal gear and a sun gear formed on the torsion shaft. The gear train constitutes the speed change means, supports the planetary gear so as to be capable of rotating, and a carrier that is coaxially rotatable relative to the center axis of the sun gear is the rotating body. Regulatory means are provided.

  In the webbing take-up device according to the fifth aspect of the present invention, the planetary gear meshes with the internal gear formed on the inner peripheral portion of the spool, and this planetary gear meshes with the sun gear formed on the torsion shaft. ing. That is, in the webbing take-up device according to the present invention, the transmission means is constituted by a planetary gear train.

  The carrier that supports the planetary gear so as to rotate is a rotating body, and when the spool rotates in the pull-out direction with respect to the torsion shaft, the carrier as the rotating body rotates in the pull-out direction at a slower speed than the spool. When the relative rotation in the pull-out direction of the spool with respect to the axial one end side of the torsion shaft reaches a predetermined number of rotations, the regulating means provided on the carrier as the rotating body interferes with the spool, and the spool rotates in the pull-out direction. To regulate.

  Thus, in the webbing take-up device according to the present invention, the transmission means is constituted by a planetary gear train. In the planetary gear train, the internal gear and the sun gear are formed coaxially. Therefore, an internal gear coaxial with the central axis of the spool is formed on the inner periphery of the spool, and is coaxial with the torsion shaft. What is necessary is just to form a sun gear in the outer peripheral part. As a result, substantially necessary parts are a planetary gear and a carrier, which can be realized with a small number of parts. In addition, since the planetary gear train can obtain a relatively high reduction ratio with a small number of stages, the speed difference between the spool and the rotating body can be increased.

  A webbing retractor according to a sixth aspect of the present invention is the spool according to the fourth aspect of the present invention, wherein the number of external teeth formed on the outer peripheral portion is set to be smaller than that of the internal gear. An external gear that meshes with the internal gear while being rotatably supported by the torsion shaft in an eccentric state is used as the transmission gear, and the external gear is used as the rotating body.

  In the webbing take-up device according to the sixth aspect of the present invention, the torsion shaft in a state in which the external transmission gear having a smaller number of teeth than the internal gear formed on the inner peripheral portion of the spool is eccentric with respect to the spool. Is rotatably supported. When the spool rotates, the rotation of the spool is transmitted to the transmission gear, and the transmission gear rotates in the pull-out direction.

  Here, when the spool makes one rotation, the transmission gear rotates in the pull-out direction earlier than the spool by the difference in the number of teeth from the internal gear. When the relative rotation of the spool with respect to the torsion shaft reaches a predetermined rotational speed, the restricting means provided on the spool interferes with the transmission gear and restricts the rotation of the transmission gear in the pull-out direction. By restricting the rotation of the transmission gear in the pull-out direction, the rotation of the internal gear in the pull-out direction, that is, the rotation of the spool in the pull-out direction is restricted.

  In this way, the rotation of the transmission gear is restricted by the restriction means provided on the spool. That is, in the webbing take-up device according to the present invention, the transmission gear constituting the transmission means also constitutes a rotating body. For this reason, the number of parts can be reduced and the configuration can be simplified.

  As described above, the webbing take-up device according to the present invention can easily set the rotation speed from the start of the relative rotation of the spool to the torsion shaft to the restriction of the relative rotation by the speed ratio in the transmission means. In addition, the variation in relative rotational speed can be reduced, and the assembling work of each part can be facilitated.

It is a rough front sectional view showing the whole webbing take-up device composition concerning a 1st embodiment. It is a side view of the spool seen from the A direction side of Drawing 1 showing the composition of the speed change means of the webbing take-up device concerning a 1st embodiment. It is a side view of the spool seen from the A direction side of FIG. 1 which shows the relationship between the rotary body and spool in the webbing take-up device according to the first embodiment. FIG. 4 is a side view of the spool corresponding to FIG. 3 showing a state where relative rotation in the pull-out direction of the spool is restricted. It is a rough front sectional view showing the whole webbing take-up device composition concerning a 2nd embodiment. FIG. 6 is a side view of the spool as viewed from the direction A in FIG. 5 showing the configuration of the speed change means of the webbing take-up device and the relationship between the rotating body and the spool according to the second embodiment. FIG. 7 is a side view of the spool corresponding to FIG. 6 showing a state where relative rotation in the pull-out direction of the spool is restricted.

  Next, each embodiment of the present invention will be described. In the following description of each embodiment, the same reference numerals are assigned to the same parts as those in the previous embodiment, and a detailed description thereof is given. Is omitted.

<Configuration of First Embodiment>
FIG. 1 is a front sectional view showing an outline of the overall configuration of the webbing take-up device 10 according to the first embodiment.

  As shown in this figure, the webbing take-up device 10 includes a frame 12. The frame 12 includes, for example, a pair of leg plates 14 and 16 that face each other substantially along the vehicle longitudinal direction. A spool 18 is provided between the leg plate 14 and the leg plate 16. The spool 18 has an axial direction along the opposing direction of the leg plates 14 and 16.

  The longitudinal base end side of the long webbing 20 is locked to the spool 18, and when the spool 18 is rotated in the winding direction which is one of the circumferences of the central axis of the spool 18, the webbing 20 is When the webbing 20 is pulled and stored on the outer peripheral portion of the spool 18 from the end side, and the webbing 20 is pulled to the tip end side, the webbing 20 wound on the spool 18 is pulled out and pulled out in the direction opposite to the winding direction. The spool 18 rotates in the direction.

  On the other hand, a torsion shaft accommodating portion 22 is formed along the center axis of the spool 18, and a torsion shaft 30 as energy absorbing means is disposed inside the torsion shaft accommodating portion 22. The torsion shaft 30 includes a rod-like torsion shaft main body 32 whose longitudinal direction is along the axial direction of the spool 18. A spool side connecting portion 34 is formed at an end portion of the torsion shaft main body 32 on the leg plate 14 side. The outer peripheral portion of the spool side connecting portion 34 is a non-circular shape such as a star shape or a polygonal shape. The inner peripheral shape of the torsion shaft accommodating portion 22 is the same as the outer peripheral shape of the spool side connecting portion 34 (strictly, a slightly smaller similar shape), and the spool side connecting portion 34 is fitted into the torsion shaft accommodating portion 22. The relative rotation of the torsion shaft 30 with respect to the spool 18 is restricted by being stuck.

  The spool-side connecting portion 34 is formed with a female screw hole 36 that opens at the end surface of the spool-side connecting portion 34 opposite to the torsion shaft main body 32. A male screw portion 42 of the stopper 40 is screwed into the female screw hole 36. The stopper 40 includes a stopper plate 44. The stopper plate 44 is formed integrally with the male screw portion 42, and when the male screw portion 42 is screwed into the female screw hole 36 and sufficiently enters the female screw hole 36, the stopper plate 44 is formed on the end surface of the spool 18 on the leg plate 14 side. Abut. As a result, inadvertent displacement of the torsion shaft 30 toward the leg plate 16 is restricted. A shaft portion 46 extends coaxially with respect to the male screw portion 42 from the surface of the stopper plate 44 opposite to the male screw portion 42.

  A spring case 50 is attached to the leg plate 14 on the outer side of the leg plate 14 (on the side opposite to the leg plate 16 of the leg plate 14), and the shaft portion 46 is rotatably supported. A spiral spring 52 is accommodated inside the spring case 50, and the spiral direction outer end of the spiral spring 52 is directly or indirectly locked to the spring case 50. An inner end portion in the spiral direction of the spiral spring 52 is locked to a locking portion 54 attached to the shaft portion 46. When the shaft portion 46 rotates in the pull-out direction, the spiral spring 52 is wound and biases the shaft portion 46 in the winding direction.

  On the other hand, a lock base 62 constituting a lock mechanism 60 as a lock means is provided on the leg plate 16 side of the spool 18. The lock base 62 includes a ratchet portion 64. On the outer periphery of the ratchet portion 64, external ratchet teeth 66 are formed around the central axis of the ratchet portion 64 at predetermined angles. A lock pawl 68 that constitutes the lock mechanism 60 together with the lock base 62 is provided on the outer side of the ratchet portion 64 in the radial direction of rotation.

  The lock pawl 68 is supported by the leg plate 16 and the like so as to be swingable around an axis whose axial direction is the same as the central axis of the spool 18. Ratchet teeth 70 are formed on the lock pawl 68. When the lock pawl 68 swings in a direction in which the ratchet teeth 70 of the lock pawl 68 approach the outer peripheral portion of the ratchet portion 64 (lock base 62), the ratchet teeth 70 of the lock pawl 68 mesh with the ratchet teeth 66 of the ratchet portion 64. The lock pawl 68 restricts the rotation of the lock base 62 in the pull-out direction.

  In addition, various parts constituting a so-called “VSIR mechanism” or “WSIR mechanism” are accommodated inside the housing 72 attached to the leg plate 16 on the outer side of the leg plate 16 (the side opposite to the leg plate 14 of the leg plate 16). Yes. When the vehicle suddenly decelerates or the rotational acceleration in the pull-out direction of the spool 18 exceeds a predetermined level, the “VSIR mechanism” or “WSIR mechanism” is activated and the ratchet teeth 70 of the lock pawl 68 are activated. Oscillates the lock pawl 68 in a direction approaching the outer periphery of the ratchet portion 64 (lock base 62).

  On the other hand, a fitting insertion portion 76 is formed at the end of the ratchet portion 64 on the spool 18 side. The fitting portion 76 is a disc whose outer peripheral shape is coaxial with the ratchet portion 64. The insertion portion 76 is inserted into a lock base insertion hole 78 opened at the end face of the spool 18 on the leg plate 16 side. The lock base insertion hole 78 has an inner diameter that is slightly larger than the outer diameter of the insertion portion 76 and has a circular shape coaxial with the spool 18. The lock base 62 is coaxially supported by the spool 18 so as to be relatively rotatable by inserting the insertion portion 76 into the lock base insertion hole 78.

  The lock base 62 having the above structure is formed with a torsion shaft fitting hole 80. The lock base side connecting portion 82 of the torsion shaft 30 formed on the opposite side of the spool side connecting portion 34 via the torsion shaft main body 32 is fitted into the torsion shaft fitting insertion hole 80.

  The outer peripheral shape of the lock base side connecting portion 82 is a non-circular shape such as a star shape or a polygon, and the inner peripheral shape of the torsion shaft fitting insertion hole 80 is the same shape as the outer peripheral shape of the lock base side connecting portion 82 (strictly, slightly The lock base side connecting portion 82 is fitted into the torsion shaft fitting insertion hole 80, so that the relative rotation of the lock base 62 with respect to the torsion shaft 30 is restricted.

  Therefore, the relative rotation of the lock base 62 with respect to the spool 18 is restricted because the torsion shaft 30 in which the spool-side coupling portion 34 is fitted in the torsion shaft accommodating portion 22 is restricted. As a result, the ratchet teeth 70 of the lock pawl 68 mesh with the ratchet teeth 66 formed on the ratchet portion 64 of the lock base 62, and when the rotation of the lock base 62 in the pull-out direction is restricted, the spool 18 is pulled in the pull-out direction. Rotation will be restricted.

  On the other hand, a planetary gear train accommodation hole 90 is formed in the spool 18. The planetary gear train accommodation hole 90 includes a large diameter hole 92. The large-diameter hole 92 has a circular shape whose inner diameter is smaller than that of the lock base fitting insertion hole 78 and larger than the maximum inner diameter of the torsion shaft accommodating portion 22. The large-diameter hole 92 is coaxially formed in the spool 18 and opens at the bottom surface of the lock base fitting insertion hole 78. The planetary gear train accommodation hole 90 is provided with a gear hole 94 as an internal gear.

  As shown in FIG. 2, the inner diameter dimension of the tooth base circle of the gear hole 94 is set smaller than the inner diameter dimension of the lock base fitting insertion hole 78 and larger than the maximum inner diameter dimension of the torsion shaft housing portion 22. The tooth base circle of the gear hole 94 is coaxially formed with respect to the spool 18, and the inner teeth are formed at regular intervals on the inner peripheral surface, and the torsion shaft housing portion 22 is opened on the bottom surface. doing.

  As shown in FIG. 1, a sun gear 96 is formed on the torsion shaft 30 on the radially inner side of the gear hole 94. As shown in FIG. 2, the sun gear 96 is an external gear coaxial with the torsion shaft main body 32 and the spool 18. As shown in FIG. 1, a carrier support portion 98 is provided between the sun gear 96 and the lock base side connecting portion 82. The carrier support portion 98 has a cylindrical shape that is smaller in diameter than the lock base side connection portion 82 and larger in diameter than the sun gear 96, and is formed coaxially with the torsion shaft main body 32 and eventually the spool 18.

  A carrier 112 as a rotating body provided in the large-diameter hole 92 is supported on the carrier support 98 so as to be rotatable around the carrier support 98. As shown in FIG. 3, the carrier 112 is formed in a disk shape coaxial with the carrier support portion 98, and a plurality of (three in this embodiment) are provided on the surface of the carrier 112 on the leg plate 14 side. The support shaft 114 is formed.

  These support shafts 114 are formed at regular intervals (in this embodiment, every 120 degrees) on one concentric circumference that is the same as the center of the carrier 112. These support shafts 114 have the same axial direction as the center axis of the spool 18, and planetary gears 122 serving as transmission gears are rotatably supported by the support shafts 114. The planetary gear 122 is an external gear and meshes with both the sun gear 96 and the gear hole 94. That is, in the present embodiment, the planetary gear train 130 which is one mode of the reduction gear train composed of the gear hole 94, the sun gear 96, the carrier 112, and the planetary gear train 130 constitutes a transmission means. .

  On the other hand, as shown in FIGS. 2 and 3, from the outer periphery of the carrier 112, a rotating body side contact portion and a plate-like carrier side contact portion 132 as a regulating means are directed outward in the radial direction of the carrier 112. The protrusion is formed. Corresponding to the carrier side contact portion 132, a spool side contact portion 134 is formed from a part of the inner periphery of the large diameter hole 92 toward the inside in the radial direction of the large diameter hole 92. The spool-side contact portion 134 faces the carrier-side contact portion 132 around the central axis of the spool 18 (that is, in the circumferential direction of the spool 18), and the spool 18 rotates relative to the carrier 112 by a predetermined angle. Then, the carrier side contact portion 132 and the spool side contact portion 134 come into contact with each other.

<Operation and Effect of First Embodiment>
Next, the operation and effect of the present embodiment will be described.

  When the vehicle is suddenly decelerated and the above-described “VSIR mechanism” is activated, the lock pawl 68 is swung, whereby the ratchet teeth 70 of the lock pawl 68 approach the ratchet teeth 66 of the ratchet portion 64. 1, the ratchet teeth 70 of the lock pawl 68 mesh with the ratchet teeth 66 of the ratchet portion 64 constituting the lock base 62.

  Further, when the occupant's body is inertially moved toward the front of the vehicle due to the deceleration of the vehicle, the webbing 20 is pulled by the occupant's body, whereby the spool 18 rotates in the pull-out direction. When the rotational acceleration in the pull-out direction of the spool 18 exceeds a predetermined level, the “WSIR mechanism” is activated. When the “WSIR mechanism” is activated, the lock pawl 68 is swung, whereby the ratchet teeth 70 of the lock pawl 68 approach the ratchet teeth 66 of the ratchet portion 64 constituting the lock base 62, and The ratchet teeth 70 mesh with the ratchet teeth 66 of the ratchet portion 64.

  In this way, the ratchet teeth 70 of the lock pawl 68 mesh with the ratchet teeth 66 of the ratchet portion 64 that constitutes the lock base 62, so that the rotation of the lock base 62 in the pull-out direction is restricted. Since the lock base 62 is connected to the spool 18 through the torsion shaft 30 in a state where relative rotation is restricted, rotation of the lock base 62 in the pull-out direction is restricted, whereby rotation of the spool 18 in the pull-out direction is performed. Is regulated. Thereby, since pulling out of the webbing 20 from the spool 18 is restricted, the occupant's body can be effectively restrained by the webbing 20, and the inertial movement of the occupant's body forward of the vehicle can be effectively suppressed.

  When the body of an occupant who intends to move inertially in the forward direction of the vehicle pulls the webbing 20 with a force of a predetermined magnitude or more in a state where the rotation of the spool 18 in the pull-out direction is restricted in this way, the pulling force corresponds to the pulling force. A rotational force in the pull-out direction is applied to the spool 18. When the rotational force in the pull-out direction applied to the spool 18 in this way exceeds the mechanical strength of the torsion shaft main body 32 in the torsion shaft 30, the lock base side connecting portion 82 side of the torsion shaft main body 32 is applied. Thus, a twist (deformation) occurs in the torsion shaft main body 32 such that the spool side connecting portion 34 side relatively rotates in the pull-out direction.

  The spool 18 rotates in the pull-out direction by the amount of relative rotation in the pull-out direction of the spool-side connecting portion 34 with respect to the lock base-side connecting portion 82 permitted by the torsion of the torsion shaft body 32, and the spool 18 moves in the pull-out direction. The webbing 20 having a length corresponding to the amount of rotation is pulled out of the spool 18. In this manner, the occupant's body can move inertially toward the front side of the vehicle by the length of the webbing 20 drawn from the spool 18, and a part of the force with which the occupant's body pulls the webbing 20 can be It is subjected to twist deformation and absorbed.

  By the way, in a state where the ratchet teeth 70 of the lock pawl 68 are engaged with the ratchet teeth 66 of the ratchet portion 64 constituting the lock base 62, the lock base side connecting portion 82 is moved in the pull-out direction even if the spool 18 rotates in the pull-out direction. There is no rotation. For this reason, even the sun gear 96 formed in the vicinity of the lock base side connecting portion 82 does not rotate in the pull-out direction, or the sun gear 96 rotates little in the pull-out direction. Therefore, when the torsion shaft main body 32 is twisted and deformed as described above, the gear hole 94 of the spool 18 rotates relative to the sun gear 96 in the pull-out direction.

  Since the planetary gear 122 is interposed between the sun gear 96 and the gear hole 94, when the gear hole 94 rotates relative to the sun gear 96 in the pull-out direction, the rotation of the gear hole 94 is decelerated and the carrier 112. The carrier 112 rotates around the carrier support 98 in the pull-out direction. The spool 18 and the carrier 112 both rotate in the pull-out direction, but the rotation speed of the carrier 112 in the pull-out direction is slower than the relative rotation speed of the sun gear 96 (that is, the spool 18) in the pull-out direction with respect to the sun gear 96.

  For this reason, when both the spool 18 and the carrier 112 rotate in the pull-out direction, the spool-side contact portion 134 formed on the spool 18 approaches the carrier-side contact portion 132 formed on the carrier 112 in the pull-out direction. . Further, when the spool 18 rotates relative to the sun gear 96 in the pull-out direction by a predetermined number of rotations, the spool side contact portion 134 contacts the carrier side contact portion 132 as shown in FIG. The contact portion 132 interferes with the spool-side contact portion 134 from the drawing direction side.

  Since the relative rotation of the spool 18 with respect to the sun gear 96 in the pull-out direction is reduced and transmitted to the carrier 112, the carrier-side contact portion 132 of the carrier 112 interferes with the spool-side contact portion 134 of the spool 18. As a result, the spool-side contact portion 134 can no longer rotate in the pull-out direction, and as a result, the spool 18 cannot rotate relative to the sun gear 96 in the pull-out direction. Thereby, the torsional deformation in the torsion shaft main body 32 of the torsion shaft 30 can be terminated.

  Here, when the number of teeth of the sun gear 96 is Sn and the number of teeth of the gear hole 94 is Rn, the reduction ratio N between the relative rotational speed of the spool 18 with respect to the sun gear 96 in the pull-out direction and the rotational speed of the carrier 112 is (1).

N = Rn / (Sn + Rn) (1)
Accordingly, when it is desired to set the number of rotations from the start to the end of the relative rotation of the spool 18 in the pull-out direction with respect to the sun gear 96 to M, the carrier-side contact portion 132 is moved from the pull-out direction side to the spool-side contact portion. The initial position of the carrier 112 may be a position where the carrier 112 is rotated in the winding direction by the number of rotations Q indicated by the following equation (2) from the state of being in contact with 134.

Q = M · Rn / (Sn + Rn) (2)
In this way, the relative rotational speed of the spool 18 from the start to the end of the relative rotation of the spool 18 with respect to the sun gear 96 in the pull-out direction can be easily set. Moreover, since the reduction ratio is determined by the number of teeth of the sun gear 96 and the gear hole 94, variations in the rotational speed from the start to the end of the relative rotation of the spool 18 can be eliminated, or such variations can be reduced. .

  Moreover, the planetary gear train 130 is assembled by assembling the planetary gear 122 to each support shaft 114 of the carrier 112, and using the outer teeth of the planetary gear 122 as both the outer teeth of the sun gear 96 and the inner teeth of the gear hole 94. You just have to bite. As described above, the assembling work of the planetary gear train 130 itself is easy. Moreover, in the assembling work, there is no variation in the rotational speed from the start to the end of the relative rotation of the spool 18 or the occurrence of the variation. Few.

  Further, since the planetary gear train 130 is provided inside the spool 18, it can be opposed to each other in the circumferential direction of the spool 18 without enlarging the carrier side contact portion 132 and the spool side contact portion 134. In addition, even if the planetary gear train 130 is operated, the components of the planetary gear train 130, the carrier side contact portion 132, the spool side contact portion 134, and the like do not move in the axial direction of the spool 18, As a result, the webbing take-up device 10 can be made compact as a whole.

  Further, in the webbing take-up device 10, since the planetary gear train 130 is used as the speed change means as the speed reduction means, a large reduction ratio can be obtained with a small number of stages. For this reason, the speed reduction means interposed between the gear hole 94 and the carrier 112 can be reduced, and as a result, the configuration can be simplified and the speed change means can be compactly integrated.

<Configuration of Second Embodiment>
Next, a second embodiment will be described.

  FIG. 5 is a front sectional view schematically showing the overall configuration of the webbing take-up device 170 according to the second embodiment.

  As shown in this figure, the webbing take-up device 170 includes a torsion shaft 172 instead of the torsion shaft 30. The torsion shaft 172 includes a gear support 174 instead of the sun gear 96. The gear support portion 174 is formed on the radially inner side of the gear hole 94 in the same manner as the sun gear 96 in the first embodiment.

  As shown in FIG. 6, the outer peripheral shape of the gear support portion 174 is circular, but its central axis is eccentric with respect to the central axis of the torsion shaft main body 32 and, consequently, the central axis of the spool 18. The gear support 174 rotatably supports a transmission gear and an external gear 182 as a rotating body. The external gear 182 is an external gear having fewer teeth than the gear hole 94, and the external gear 182 is located on the eccentric side of the central axis of the gear support portion 174 with respect to the central axis of the torsion shaft main body 32. Are engaged.

  A gear side contact portion 184 as a rotating body side contact portion is formed on the leg plate 16 side of the external gear 182. As shown in FIG. 6, the gear-side contact portion 184 extends further outward in the rotational radial direction of the external gear 182 than the tooth tip of the external gear 182 inside the large-diameter hole 92.

  Corresponding to the external gear 182, a spool side contact portion 186 is formed as a restricting means from a part of the inner periphery of the large diameter hole 92 toward the inside in the radial direction of the large diameter hole 92. The spool side abutting portion 186 has the same configuration as the spool side abutting portion 134 in the first embodiment, but unlike the spool side abutting portion 134, the spool side abutting portion 186 is an aspect of the regulating means. Therefore, the explanation was given with another reference. That is, in the present embodiment, the speed increasing gear train 190 constituted by the gear hole 94 and the external gear 182 is used as the transmission means.

<Operation and Effect of Second Embodiment>
Next, the operation and effect of the present embodiment will be described.

  In the webbing take-up device 170, when the ratchet teeth 70 of the lock pawl 68 are engaged with the ratchet teeth 66 of the ratchet portion 64 constituting the lock base 62, the lock base side connecting portion 82 even if the spool 18 rotates in the pull-out direction. The gear support portion 174 formed in the vicinity of is not rotated in the pull-out direction, or the gear support portion 174 is not rotated in the pull-out direction. Therefore, when the torsion shaft main body 32 is twisted and deformed as described above, the gear hole 94 of the spool 18 rotates relative to the gear support portion 174 in the pull-out direction.

  Thus, when the spool 18 rotates in the pull-out direction, the external gear 182 that meshes with the gear hole 94 rotates in the pull-out direction. Although both the spool 18 and the external gear 182 rotate in the pull-out direction, the external gear 182 rotates in the pull-out direction earlier than the spool 18 because the external gear 182 has fewer teeth than the gear hole 94. To do.

  When both the spool 18 and the external gear 182 rotate in the pull-out direction, the gear-side contact portion 184 formed on the external gear 182 approaches the spool-side contact portion 186 formed on the spool 18 in the pull-out direction. To do. Further, when the spool 18 rotates relative to the gear support portion 174 in the pull-out direction by a predetermined number of rotations, the gear side contact portion 184 contacts the spool side contact portion 186 as shown in FIG. The side contact portion 186 interferes with the gear side contact portion 184 from the drawing direction side.

  Since the relative rotation in the pull-out direction of the spool 18 with respect to the gear support portion 174 is increased and transmitted to the external gear 182 to the external gear 182, the spool-side contact portion 186 of the spool 18 is connected to the external gear 182. A gear hole 94 that meshes with the external gear 182 having the gear side abutting portion 184 because the gear side abutting portion 184 cannot further rotate in the pull-out direction due to interference with the gear side abutting portion 184. That is, the spool 18 cannot relatively rotate in the drawing direction. Thereby, the torsional deformation in the torsion shaft main body 32 of the torsion shaft 30 can be terminated.

  Here, if the number of teeth of the gear hole 94 is Rn, and the number of teeth of the external gear 182 is Gn, the rotational speed of the external gear 182 in the pull-out direction relative to the relative rotational speed of the spool 18 with respect to the gear support portion 174 The speed increasing ratio N is expressed by the following equation (3).

N = Rn / Gn (3)
Therefore, when it is desired to set the rotation speed from the start to the end of the relative rotation of the spool 18 with respect to the gear support portion 174 to M, the spool-side contact portion 186 is engaged with the gear-side contact from the pull-out direction side. The position where the external gear 182 rotates in the winding direction from the state in contact with the portion 184 by the rotational speed Q shown by the following equation (4) may be set as the initial position of the external gear 182.

Q = M · Rn / Gn (4)
For this reason, it is possible to easily set the relative rotational speed of the spool 18 from the start to the end of the relative rotation of the spool 18 with respect to the gear support portion 174 in the drawing direction. Moreover, since the speed increasing ratio is determined by the number of teeth of the external gear 182 and the gear hole 94, variation in the rotational speed from the start to the end of the relative rotation of the spool 18 is eliminated or such variation is eliminated. Can be small.

  Moreover, the speed increasing gear train 190 can be assembled by assembling the external gear 182 to the gear support 174 set on the torsion shaft 172 and meshing the external gear 182 with the internal teeth of the gear hole 94. . As described above, the assembling work of the speed increasing gear train 190 itself is easy, and in the assembling work, there is no variation in the rotational speed from the start to the end of the relative rotation of the spool 18 or the occurrence of the variation. Less is.

  Further, since the speed increasing gear train 190 is provided inside the spool 18, it can be opposed to each other in the circumferential direction of the spool 18 without enlarging the gear side contact portion 184 and the spool side contact portion 186. Moreover, even if the speed increasing gear train 190 is operated, the components of the speed increasing gear train 190, the gear side contact portion 184, the spool side contact portion 186, and the like do not move in the axial direction of the spool 18. The spool 18, and consequently the webbing take-up device 170 can be made compact as a whole.

  Furthermore, since the webbing take-up device 170 uses the speed increasing gear train 190 as the speed changing means as the speed increasing means, only the external gear 182 is required as a separate component, and the number of parts is small. realizable.

  In each of the embodiments described above, the ratchet teeth 66 of the lock pawl 68 supported by the leg plate 16 and the like are engaged with the ratchet teeth 66 of the external teeth formed on the lock base 62, whereby the lock base in the pull-out direction is obtained. The rotation of 62 was restricted. However, the locking means is not limited to such a configuration, and the locking means is activated when the vehicle suddenly decelerates or when the rotational acceleration in the pull-out direction of the spool 18 exceeds a predetermined magnitude. Any configuration that restricts rotation of the lock base to be configured in the pull-out direction may be used. Therefore, for example, a lock pawl that is displaceable in the rotational radius direction of the lock base is provided on the lock base, and the lock pawl meshes with an internal ratchet wheel formed on the leg plate 16, thereby restricting rotation of the lock base in the pull-out direction. It may be configured.

10 Webbing take-up device 18 Spool 20 Webbing 30 Torsion shaft 60 Lock mechanism (locking means)
62 Lock base 94 Gear hole (internal gear)
96 sun gear 112 carrier (rotating body)
122 Planetary gear (transmission gear)
130 Planetary gear train (transmission means)
132 Carrier side contact part (rotating body side contact part, regulating means)
134 Spool side contact portion 170 Webbing take-up device 172 Torsion shaft 182 External gear (transmission gear, rotating body)
184 Gear side contact part (rotating body side contact part)
186 Spool side contact part (regulating means)
190 Speed-up gear train (transmission means)

Claims (6)

A spool for winding the webbing from its longitudinal base end by rotating in the winding direction;
A torsion shaft provided inside the spool and connected to the spool in a state in which relative rotation with respect to the spool is restricted on the other end side of the spool in the axial direction;
A lock base provided on one end of the spool in the axial direction and connected to the torsion shaft in a state where relative rotation with respect to the torsion shaft is restricted, is opposite to a sudden deceleration state of the vehicle or the winding direction of the spool. A lock mechanism that operates when the rotational acceleration in the pulling-out direction is equal to or greater than a predetermined magnitude and restricts the rotation of the lock base in the pulling-out direction;
A rotating body provided on one axial end side of the spool and rotatable around an axis having the same direction as the central axis of the spool as an axial direction;
The spool is actuated by relative rotation of the spool in the pull-out direction with respect to the torsion shaft at one axial end side of the spool, and the speed of the relative rotation of the spool is changed and transmitted to the rotating body to transmit the rotating body to the rotating body. Transmission means for rotating in the pull-out direction;
The spool and the rotating body are provided on the slower one of the rotation speeds in the pull-out direction in the operating state of the speed change means, and when the relative rotation of the spool reaches a predetermined number of rotations, the spool and Restriction means for restricting rotation in the withdrawal direction of the slower one by interfering with the faster rotational speed in the withdrawal direction in the operating state of the transmission means in the rotating body;
A webbing take-up device comprising:   The webbing take-up device according to claim 1, wherein the rotating body is disposed inside the spool at one axial end side of the spool.   A spool-side abutting portion is formed on one end side in the axial direction of the spool, on the outer side in the rotational radial direction of the spool with respect to the center axis line of the spool, and at least the one end side in the axial direction of the torsion shaft in the pull-out direction of the spool. In the state where the relative rotation has reached a predetermined number of rotations, a rotating body side contact portion facing the spool side contact portion in the rotational circumferential direction of the rotating body is formed on the rotating body, and the spool side contact The webbing take-up device according to claim 1, wherein any one of the portion and the rotating body side contact portion is used as the restricting means. An internal gear formed on the inner periphery of the spool;
A transmission gear that meshes with the internal gear and rotates by relative rotation of the spool in the pull-out direction with respect to the torsion shaft to shift the rotation of the internal gear;
The webbing take-up device according to any one of claims 1 to 3, wherein the speed change means is configured to include a gear. A planetary gear meshing with the internal gear;
A sun gear formed on the torsion shaft;
The transmission means is constituted by a planetary gear train including
5. The support according to claim 4, wherein the planetary gear is supported so as to be capable of rotating, and a carrier that is coaxially rotatable relative to a center axis of the sun gear is used as the rotating body, and the restricting unit is provided on the rotating body. Webbing take-up device.   The external teeth formed on the outer peripheral portion are set to be smaller than the internal gears and are externally engaged with the internal gears while being rotatably supported by the torsion shaft in an eccentric state with respect to the spool. The webbing take-up device according to claim 4, wherein a tooth gear is the transmission gear, and the external gear is the rotating body.

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