JP4113408B2 - Webbing take-up device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a webbing take-up device, and more particularly, to a webbing take-up device including a pretensioner mechanism that tensions a webbing in a passenger restraining direction when a vehicle is suddenly decelerated.
[0002]
[Prior art]
In the webbing take-up device, an occupant-restraining webbing is wound in layers on a take-up shaft supported by a frame. When the take-up shaft rotates in one direction, the webbing is taken up, and the take-up shaft When it rotates in the direction, the webbing is pulled out. The winding shaft is weakly urged in the winding direction of the webbing by the mainspring spring so as not to give an unpleasant restraint feeling to the occupant while following the posture change of the occupant.
[0003]
Further, in such a webbing take-up device, in order to limit the amount of movement of the occupant due to the inertia force at the time of sudden deceleration of the vehicle such as a collision, the webbing is tensioned in the occupant restraint direction during the sudden deceleration of the vehicle (the webbing is forced Some have a pretensioner mechanism.
[0004]
As a pretensioner mechanism, for example, a rack and pinion type is known. Specifically, a pinion connected to the take-up shaft and rotating integrally with the take-up shaft, a rack meshable with the pinion, a piston formed integrally with the rack, and a frame near the pinion are fixed. And a cylinder in which the piston is movably inserted in the axial direction, and the piston is driven by the gas pressure of the gas supplied to the cylinder when the vehicle suddenly decelerates, and the rack meshes with the pinion as the piston moves In this configuration, the winding shaft is rotated in the webbing winding direction.
[0005]
By the way, in the webbing take-up device equipped with the pretensioner mechanism as described above, the rack is pinned so that the rotation of the take-up shaft, that is, the rotation in both the webbing take-up direction and the webbing pull-out direction is not hindered in normal times. It is placed at a position where it does not interfere.
[0006]
However, in such a conventional webbing take-up device, when the rack meshes with the pinion, a large load acts on the rack and the pinion. Therefore, it is necessary to increase the tooth thickness of the front tooth of the rack and the tooth of the pinion. In addition, the degree of freedom in designing the rack and the pinion is lowered and the workability is deteriorated. In addition, since the pinion rotates integrally with the take-up shaft, after the pretensioner mechanism is activated, when the webbing is pulled out again for energy absorption, the force that pushes the piston back in the cylinder is exerted via the rack and pinion. It acts on the take-up shaft and may cause a problem in preventing proper energy absorption.
[0007]
As a countermeasure, a configuration in which a one-way clutch of a roller type or a sprag type is provided between the pinion and the winding shaft is also known (see, for example, Patent Document 1). An outline of such a clutch will be described with reference to FIG.
[0008]
The clutch 100 shown in this figure includes a clutch portion 104 having an inner peripheral surface that is opposed to the outer peripheral surface of the winding shaft 102 over the entire periphery, and the clutch portion 104 rotates integrally with the pinion. It has become. Three recesses 106 are formed on the inner peripheral surface of the clutch portion, and a roller 108 is disposed in each recess 106. The clutch 100 is normally disconnected when the roller 108 is positioned in a wide portion between the concave portion 106 and the outer peripheral surface of the winding shaft 102, and the winding shaft 102 is rotatable in each direction of winding and withdrawal of the webbing. Has been.
[0009]
On the other hand, in the clutch 100, when the pinion (that is, the clutch portion 104) is rotated in the webbing winding direction indicated by the arrow E, the roller 108 is a narrow portion between the concave portion 106 and the outer peripheral surface of the winding shaft 102. The rotation of the pinion is coupled to the winding shaft 102 so as to be able to be transmitted. When the winding shaft 102 rotates in the webbing pull-out direction (the direction opposite to the arrow E) after the pretensioner mechanism is activated, the roller 108 is moved to the wide portion between the recess 106 and the outer peripheral surface of the winding shaft 102. By moving, the winding shaft 102 is separated from the pinion again.
[0010]
As a result, in the pretensioner device including the clutch 100, normally, the winding shaft is forcibly rotated in the webbing winding direction when the vehicle suddenly decelerates while keeping the webbing winding and drawing freely by the winding device. can do. For this reason, the pinion and the rack can be meshed in advance, and the load acting on the rack and the pinion is reduced. In addition, after the pretensioner mechanism is activated, proper energy absorption is not hindered when the webbing is allowed to be drawn again for energy absorption.
[0011]
[Patent Document 1]
Japanese Patent Publication No. 2-20743
[0012]
[Problems to be solved by the invention]
However, in the configuration provided with such a one-way clutch, the winding shaft and the rotating body have a function of being coupled or disconnected so as to be able to transmit the rotational force via rollers arranged in the same plane between each other. In other words, in other words, since the winding shaft and the rotating body cannot be directly coupled to establish the one-way clutch, there is a possibility that slip occurs between the winding shaft and the rotating body. In particular, since the roller transmits the rotational force while being sandwiched between the winding shaft and the rotating body in a substantially linear contact state, slippage is likely to occur between the roller and the winding shaft in the initial operation of the pretensioner mechanism.
[0013]
For this reason, in the clutch structure of such a conventional webbing take-up device, a time lag from the operation of the pretensioner mechanism to the actual start of webbing take-up and a transmission loss of the driving force (torque) occur, and the slip is caused by the pretensioner mechanism. It was a hindrance to further improvement of the initial restraint performance. Conversely, if it is attempted to reduce the slip between the take-up shaft and the roller, the clutch is not smoothly disengaged when the webbing is allowed to be pulled out again after the pretensioner mechanism is actuated.
[0014]
In view of the above-described facts, an object of the present invention is to provide a webbing take-up device that can prevent or suppress slipping of a clutch that transmits the rotational force of a rotating member to a take-up shaft, and that improves initial restraint performance.
[0015]
[Means for Solving the Problems]
  In order to achieve the above object, a webbing take-up device according to a first aspect of the present invention is a take-up shaft that is rotatably supported by a frame fixed to a vehicle body and from which an occupant-restraining webbing is taken up and pulled out. A rotating member provided coaxially with the take-up shaft and rotated in the webbing take-up direction of the take-up shaft during sudden deceleration of the vehicle, and when the rotating member is rotated in the webbing take-up direction, A webbing take-up device comprising: a clutch that transmits the rotational force of the rotating member to the take-up shaft; and the clutch is provided integrally with the take-up shaft; A driving unit that is provided opposite to the driven unit and that is coupled to the driven unit so as to transmit the rotational force when moved in the axial direction, and holds the driving unit in a separated position with respect to the driven unit.forHolding means andAnd a biasing means provided between the frame and the rotating member or between the rotating member and the take-up shaft, and biasing the rotating member in a direction in which the drive unit is separated from the driven portion.A coupling means for converting a part of the rotational force of the rotating member in the webbing take-up direction into a moving force in the axial direction and coupling the drive unit to the driven unit. It is a feature.
[0016]
In the webbing take-up device according to the first aspect of the present invention, the clutch drive unit is normally held at a position away from the driven unit by the holding means, and the take-up shaft is separated from the rotating member. For this reason, the webbing can be taken out and pulled out freely.
[0017]
On the other hand, when the vehicle is suddenly decelerated, the rotating member is rotated in the webbing take-up direction. A part of the rotational force of the rotating member is converted into a moving force in the axial direction of the rotating member by the coupling means, and a driving unit integrated with the rotating member is coupled to the driven portion so that the rotational force of the rotating member can be transmitted. Needless to say, this coupling may be in any form such as engagement, contact, fitting, etc., as long as rotational force can be transmitted.
[0018]
As a result, the driven part is rotationally driven by the driving part, and the winding shaft integrated with the driven part is rotated in the webbing winding direction, whereby the webbing is wound up and tensioned to the occupant restraint. That is, the pretensioner function is performed.
[0019]
Here, since the drive unit disposed opposite to the driven unit moves in the axial direction and is coupled to the driven unit, the clutch is normally separated from the rotating member by winding the drive unit and the driven unit in the axial direction. The rotation of the take-up shaft is ensured by separating the shaft, and the driving portion and the driven portion are directly coupled so as to be able to transmit the rotational force when the vehicle suddenly decelerates.
[0020]
Therefore, for example, the driving part and the driven part are gear-coupled (direct engagement by meshing), or the driving part and the driven part are knurled (increase the friction coefficient while increasing the contact area). Further, it is possible to adopt a configuration in which slip does not occur between the drive unit and the driven unit or slip hardly occurs. As a result, the time lag and driving force transmission loss until the actual webbing winding start in the initial operation of the pretensioner function is suppressed or prevented, and the initial restraint performance is improved.
[0021]
Thus, in the webbing take-up device according to the first aspect, slipping of the clutch that transmits the rotational force of the rotating member to the take-up shaft can be prevented or suppressed, and the initial restraint performance is improved.
[0022]
  In addition, since the clutch that normally separates the rotating member and the winding shaft is provided, for example, in a configuration in which the pinion as the rotating member is driven to rotate by the rack, the pinion and the rack can be meshed in advance. Yes. Furthermore, since the drive part of the rotating member and the driven part of the take-up shaft are directly coupled without interposing parts such as rollers, the number of parts can be reduced.
  Furthermore, in this webbing take-up device, the drive unit is normally held in the direction away from the driven part by the urging force of the urging means acting on the rotary member (drive part), and the take-up shaft is separated from the rotary member. Yes. When the rotating member is rotated during the sudden deceleration of the vehicle, the driving unit moves in the axial direction against the urging force of the urging unit by the axial moving force converted by the coupling unit, and engages with the driven unit. .
  Further, when the pretensioner function is fulfilled and no rotational force acts on the rotating member, the axial moving force also does not act, and the rotating member, that is, the drive unit is separated from the driven unit by the biasing force of the biasing means. Return to position. For this reason, even in the configuration in which the webbing is allowed to be drawn again for energy absorption after the pretensioner function is completed, proper energy absorption is not hindered.
  That is, the clutch according to the present invention has a function of separating the drive unit and the driven unit after completion of the pretensioner function while maintaining the function of preventing or suppressing the slip.

[0023]
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 coupling means is fixed to the engaging portion provided on the rotating member and the frame, and the rotating member Engaging portion with which the engaging portion engages when rotating in the webbing take-up direction, and at least one of the engaging portion and the engaged portion of the engaged portion, The taper portion is inclined with respect to the rotation direction of the rotating member.
[0024]
In the webbing take-up device according to claim 2, a taper portion formed at at least one of engagement portions where the engaging portion of the rotating member and the engaged portion fixed to the frame engage with each other (the tapered portion). Part of the rotational force of the rotating member is converted into a moving force in the axial direction by the inclination of the tapered portion with respect to the rotational direction.
[0025]
For this reason, the clutch which a drive part moves to an axial direction and couple | bonds with a driven part with a simple structure is implement | achieved.
[0026]
A webbing take-up device according to a third aspect of the invention is the webbing take-up device according to the first aspect, wherein the rotating member is a helical gear that is rotationally driven by the movement of a helical rack that meshes with each other, and The helical gear and the helical rack whose meshing surfaces are inclined in the direction in which the helical gear driven to rotate in the winding direction moves toward the driven part by a thrust force, and the coupling means It is composed.
[0027]
In the webbing take-up device according to the third aspect, when the helical rack moves while meshing with the helical gear which is a rotating member during the sudden deceleration of the vehicle, the helical gear rotates. Along with this rotation, the helical gears are designed such that the meshing surfaces of the helical gears with the helical rack are inclined in the direction in which the helical gears move to the driven part side by the thrust force. It moves to the driven part side in the axial direction by the thrust force that is a part of the force transmitted from the rack.
[0028]
Then, the drive part integrally provided in the helical gear which is a rotation member couple | bonds with a driven part, and a winding shaft rotates in the winding direction of webbing. The helical rack and the helical gear may be meshed in advance or may be meshed after the start of the movement of the helical rack, but are preferably meshed in advance.
[0029]
Here, the coupling means is composed of the helical gear and the helical rack that mesh with each other so that the helical gear is moved to the driven part side by thrust force at least during rotation. Since the helical rack that is driven to rotate and the helical gear that is the rotary member itself constitute (also serve as) a coupling means, the number of parts can be greatly reduced. Further, the structure can be simplified and the size of the pretensioner mechanism (that is, the webbing take-up device) can be reduced. Furthermore, with the reduction in the number of parts and the simplification of the structure, the assembly man-hours can be reduced and the assembly workability can be improved.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
A webbing retractor 10 according to a first embodiment of the present invention will be described with reference to FIGS.
[0035]
FIG. 1 is a schematic cross-sectional view showing the overall configuration of the webbing take-up device 10. As shown in this figure, the webbing take-up device 10 includes a frame 12. The frame 12 has a pair of leg pieces 12A and 12B facing each other and a back piece 12C connecting the leg pieces, and is formed in a substantially U shape in plan view. The back piece 12C extends downward, and its lower end is bolted to the vehicle body and fixed.
[0036]
Between the leg pieces 12A and 12B facing each other of the frame 12, a cylindrical spool 14 whose axial direction is the opposite direction of the leg pieces 12A and 12B is provided. One end of a webbing 16 for restraining an occupant is locked to the spool 14 and a part of the webbing 16 is wound around. The rotation of the spool 14 allows the webbing 16 to be wound and pulled out from the spool 14. Become.
[0037]
That is, the webbing 16 is wound up when the spool 14 rotates in one direction around the axis, and the webbing 16 is pulled out when the spool 14 rotates in the other direction around the axis.
[0038]
In the cylinder of the spool 14, a lock base 18 is disposed at the end on the leg piece 12A side. The lock base 18 is inserted through the opening of the leg piece 12 </ b> A of the frame 12, and is supported by a bearing (not shown) coaxially with the spool 14 and rotatably with respect to the spool 14 and the frame 12.
[0039]
The lock base 18 is provided with a lock plate 26 constituting a lock means. The lock plate 26 is formed so as to be able to bite into an internal tooth ratchet 12D provided in the opening of the leg piece 12A. The lock plate 26 rotates in the webbing pull-out direction of a V gear (not shown) when an acceleration sensor (not shown) detects an acceleration (deceleration) of a predetermined value or more or when the pulling speed of the webbing 16 exceeds a predetermined value. When the lock base 18 attempts to rotate in the webbing pull-out direction, the lock base 18 is guided by the V gear and engaged with the internal ratchet 12D to prevent the lock base 18 from rotating in the webbing pull-out direction.
[0040]
Further, the lock base 18 is inserted with a hexagonal portion 20A provided at one end of a torsion bar 20 disposed at the in-cylinder axial center portion of the spool 14, and the lock base 18 always has a hexagonal portion of the torsion bar 20. It is configured to rotate integrally with 20A.
[0041]
On the other hand, a sleeve 22 is disposed at the end of the spool 14 on the side of the leg piece 12B. The sleeve 22 is coaxially and integrally connected to the spool 14 by fitting the spline-like teeth 24. A key groove portion 52 as a driven portion constituting a clutch to be described later is formed on an end surface of the sleeve 22 exposed to the outside of the spool 14, which will be described later.
[0042]
A support shaft portion 22A that is inserted through the opening of the leg piece 12B is coaxially and integrally provided at the distal end portion of the sleeve 22, and an end portion that protrudes outward from the leg piece 12B of the support shaft portion 22A. Is rotatably supported by a bearing portion (not shown). Further, a mainspring spring (not shown) is provided at the end of the support shaft portion 22A, and the sleeve 22 is always urged to rotate in the direction in which the webbing 16 is wound up.
[0043]
Further, the sleeve 22 is connected to the lock base 18 by inserting a hexagonal portion 20 </ b> B provided at the other end of the torsion bar 20. Thus, normally, the spool 14, the lock base 18, the torsion bar 20, and the sleeve 22 are configured to rotate integrally.
[0044]
That is, in the above configuration, the spool 14, the lock base 18, the torsion bar 20, and the sleeve 22 correspond to the “winding shaft” in the present invention.
[0045]
Further, as shown in FIG. 2, the webbing retractor 10 includes a pretensioner mechanism 30 having a clutch function, and the pretensioner mechanism 30 includes a rotating body 32.
[0046]
As shown in detail in FIGS. 3A and 3B, the rotating body 32 includes a pinion 34 as a rotating member that constitutes a pretensioner mechanism, a gear portion 36 as a driving portion that constitutes a clutch, A disc portion 40 provided with an inclined projection 38 as an engaging portion is formed coaxially and integrally.
[0047]
A support hole 42 penetrating the rotary body 32 in the longitudinal direction is provided in the axial center portion of the rotary body 32, and is freely rotatable on the support shaft portion 22 </ b> A of the sleeve 22 (that is, relative to the spool 14. Possible)).
[0048]
The pinion 34 is provided on one end side of the rotating body 32 and has a tooth width (that is, an axial dimension) larger than a tooth width of a rack 54 described later.
[0049]
Further, the gear portion 36 is provided on the other end side of the rotating body 32, and protrudes in the axial direction from the end face, and extends radially from the outside of the support hole 42 (in the first embodiment, the plurality of gear portions 36). 8) gear teeth 36A. The axial tip of the gear tooth 36A is rounded.
[0050]
Further, the disc part 40 is provided between the pinion 34 and the gear part 36, and the outer diameter thereof is sufficiently larger than the outer diameters of the pinion 34 and the gear part 36. A plurality (five in the first embodiment) of inclined projections 38 project in the axial direction of the rotating body 32 on the end surface of the disk portion 40 on the pinion 34 side. The inclined protrusions 38 are coaxially arranged with the rotating body 32 and are arranged at equal intervals along a virtual circumference outside the pinion 34.
[0051]
Each of these inclined projections 38 is formed with a tapered portion 38A. Each taper portion 38A has an arrow so that the protruding height from the disc portion 40 on the side of the winding direction of the webbing 16 (the rotation direction indicated by arrow A in FIGS. 2 and 3A) is reduced. It is inclined with respect to the A direction.
[0052]
Further, an annular rib 40A along the outer peripheral surface of the disc portion 40 on the end surface on the side of the gear portion 36 protrudes in the axial direction of the rotating body 32. Has been.
[0053]
The rotating body 32 described above is configured to be supported by the support shaft portion 22A of the sleeve 22 so that the gear portion 36 faces the sleeve 22. In this state, a plate 44 fixed to the leg piece 12B of the frame 12 is arranged outside the disc portion 40 as shown in the schematic cross-sectional view along the line 4-4 in FIG. Has been.
[0054]
The plate 44 has a through hole 46 (see FIG. 2) through which the pinion 34 is inserted, and an engagement hole 48 that is formed substantially corresponding to the shape of each inclined projection 38 in side view and into which each inclined projection 38 is inserted. is doing. In FIG. 2, the illustration of the plate 44 is omitted, and only the through holes 46 and the engagement holes 48 are indicated by imaginary lines.
[0055]
Thus, when the rotating body 32 is rotated in the direction of arrow A, the tapered portions 38A of the inclined protrusions 38 are engaged with the hole walls of the engaging holes 48, and the rotating body 32 (pinion) is inclined by the inclination of the tapered portions 38A. A part of the rotational force 34) is converted into a moving force in the axial direction (the proximity direction to the sleeve 22 indicated by the arrow B in FIGS. 1 and 4). That is, the hole wall on the arrow A side of each engagement hole 48 corresponds to the “engaged portion” in the present invention.
[0056]
In addition, the rotating body 32 includes the leg pieces 12B of the frame 12 and the disc portion 40 in a state where the pinions 34 are inserted into the through holes 46 of the plate 44 and the inclined protrusions 38 are inserted into the engaging holes 48. It is urged | biased by the direction opposite to the arrow B direction by the leaf | plate spring 50 as a holding means and urging | biasing means arrange | positioned between ribs 40A.
[0057]
That is, the rotator 32 is normally held at a position away from the sleeve 22 by the urging force of the leaf spring 50. When the rotator 32 is driven to rotate in the direction of the arrow A, the urging force of the leaf spring 50 ( The sleeve 22 comes close to the elastic force). In addition, the movement of the rotating body 32 in the direction opposite to the arrow B direction is a configuration that is regulated by the disc portion 40 coming into contact with the plate 44. Further, it is preferable that a bearing be provided between the leaf spring 50 and the disc portion 40 or the leg piece 12B so that the leaf spring 50 does not hinder the rotation of the rotating body 32.
[0058]
On the other hand, a key groove portion 52 that can be engaged with the gear teeth 36 </ b> A of the gear portion 36 is formed on the end surface of the sleeve 22 facing the gear portion 36 of the rotating body 32. As shown in FIG. 5, among the groove walls defining the key groove portion 52, the groove wall opposite to the arrow A side is a curved surface 52A for guiding the gear teeth 36A.
[0059]
As a result, even if the gear teeth 36A that rotate in the direction of arrow A and move in the direction of arrow B and try to enter the key groove 52 come into contact with the curved surface 52A, the corresponding contact is inclined with respect to the direction of arrow B. A force in the C direction is applied, so that the gear teeth 36A engage with the key groove portion 52 reliably and smoothly.
[0060]
In the above configuration, the inclined projection 38 provided in the disk portion 40 integral with the pinion 34 and having the tapered portion 38A, and the engagement hole 48 provided in the plate 44 fixed to the frame 12 are the “coupling means” in the present invention. The key groove portion 52, the gear portion 36 (gear teeth 36A), and the leaf spring 50 together with these constitute a “clutch” in the present invention.
[0061]
Further, the pretensioner mechanism 30 includes a mechanism that applies a rotational force in the direction of arrow A to the pinion 34. Specifically, the pretensioner mechanism 30 includes a rack 54, and one end side of the rack 54 is meshed with the pinion 34 in the assembled state. As described above, the tooth width of the rack 54 is sufficiently smaller than the tooth width of the pinion 34, and the rack 54 meshes with the disk portion 40 side of the pinion 34 in the initial state. Then, as described above, when the rotating body 32 moves in the direction of arrow B along with the rotation of the pinion 34 in the direction of arrow A, the meshing position moves to the end side of the pinion 34.
[0062]
In the operating range of the pretensioner mechanism 30 (the amount of rotation of the pinion 34 by the rack 54 set to wind the webbing 16 by a predetermined amount, that is, the range of movement to the arrow B side), the pinion 34 and the rack 54 The dimensions of each part are determined so that the engagement with the shaft does not come off in the axial direction.
[0063]
A piston 56 is integrally provided on the other end side of the rack 54. The piston 56 is slidably inserted into a cylinder 58 which is fixed to the leg piece 12B of the frame 12 and opened upward.
[0064]
In addition, a gas supply device 60 that generates a large amount of gas when operated (for example, ignited) is connected to the bottom of the cylinder 58. Control means (not shown) is electrically connected to the gas supply device 60, and the control means is configured to operate the gas supply device 60 when the vehicle suddenly decelerates.
[0065]
As a result, when the vehicle suddenly decelerates, gas is supplied into the cylinder 58, and the gas pressure of this gas moves the piston 56 to the opening end side of the cylinder 58 (in the direction of arrow D in FIG. 2) and meshes with the rack 54. The pinion 34 is rotated in the direction of arrow A (winding direction of the webbing 16).
[0066]
Next, the operation of the first embodiment will be described.
[0067]
In the webbing take-up device 10 configured as described above, the spool 14 and the lock base 18 are connected via the torsion bar 20 and the sleeve 22, so that they normally rotate together. Further, since the gear portion 36 and the key groove portion 52 of the pretensioner mechanism 30 are separated by the urging force of the leaf spring 50, the rack 54 meshed with the pinion 34 does not become an obstacle to the rotation of the spool 14. . For this reason, normally, the webbing 16 can be freely taken out and pulled out.
[0068]
When the vehicle suddenly decelerates, first, the pretensioner mechanism 30 operates. Specifically, when the control means operates the gas supply device 60, the piston 56 is slid in the direction of arrow D in FIG. 2 by the pressure of the gas supplied into the cylinder 58, and the rack 54 moves while meshing with the pinion 34. As a result, the pinion 34 is rotated in the direction of arrow A. That is, the rotating body 32 rotates in the direction of arrow A.
[0069]
Then, the inclined protrusion 38 of the disc part 40 engages with the edge (hole wall) of the engaging hole 48 of the plate 44 at the tapered part 38A, and the tapered part 38A of the inclined protrusion 38 and the engaging hole 48 are mutually connected. Part of the rotational force in the direction of arrow A of the pinion 34 (rotating body 32) is converted into a moving force in the direction of arrow B while being engaged. Thereby, the rotating body 32 moves in the arrow B direction against the urging force of the leaf spring 50 while rotating in the arrow A direction.
[0070]
By this movement, the gear teeth 36A of the gear portion 36 formed on the arrow B side end portion of the rotating body 32 mesh with the key groove portion 52 formed on the opposite end surface of the sleeve 22, and the rotational force of the pinion 34 is applied to the sleeve 22. Is transmitted to.
[0071]
Since the sleeve 22 is connected so as to rotate integrally with the spool 14 by spline-like teeth 24, the spool 14 rotates in the direction of arrow A by the rotational force transmitted to the sleeve 22 and winds the webbing 16. At this time, when the inclined projection 38 comes out of the engagement hole 48, the gear portion 36 and the key groove portion 52 tend to be separated from each other by the urging force of the leaf spring 50, but the gear teeth 36A and the groove wall of the key groove portion 52 are separated from each other. The axial frictional force that counteracts the meshing force (force in the direction of arrow A) against the biasing force of the leaf spring 50 maintains the meshing state. That is, the gear portion 36 is held against the urging force of the leaf spring 50 by the meshing force with the key groove portion 52.
[0072]
When the rack 54 reaches the movement limit in the direction of arrow D, the rotational driving force does not act on the pinion 34 and the winding of the webbing 16 by a predetermined amount is completed. As a result, the webbing 16 is loosely removed and is tightly attached to the occupant (the operation of the pretensioner mechanism 30 is completed).
[0073]
Since the meshing force due to the rotation between the gear portion 36 and the key groove portion 52 is also eliminated, the rotating body 32 moves in the direction opposite to the arrow B by the urging force of the leaf spring 50, and the initial position in the axial direction. Return to. As a result, the gear portion 36 comes out of the key groove portion 52 and is separated (clutch engagement is released).
[0074]
On the other hand, since the predetermined acceleration (deceleration) accompanying the rapid deceleration of the vehicle has already been detected when the pretensioner mechanism 30 is operated, the rotation of the V gear constituting the lock means in the webbing pull-out direction (the direction opposite to the arrow A) Is blocked.
[0075]
For this reason, after the pretensioner mechanism 30 is actuated, a tensile force accompanying the inertial movement of the occupant acts on the webbing 16, and the lock base 18 attempts to rotate in the webbing pull-out direction via the spool 14, the sleeve 22, and the torsion bar 20. The lock plate 26 is guided by the V gear and is engaged with the internal ratchet 12D of the frame 12. As a result, rotation of the lock base 18, that is, the one end side hexagonal portion 20 </ b> A of the torsion bar 20 in the webbing pull-out direction is prevented.
[0076]
In this state, the webbing 16 is pulled out while resisting a force limiter load that is a torsional load of the torsion bar 20 (while maintaining a constant load acting on the webbing 16 (occupant)), and energy absorption is performed. .
[0077]
Here, since the gear portion 36 (the rotating body 32) and the key groove portion 52 (sleeve 22) are contacted and separated in the axial direction to engage and disengage the clutch, the gear portion 36 and the key groove portion 52 are normally connected to each other in the shaft direction. The clutches are disengaged in the direction away from each other (not located in the same plane), and when the pretensioner mechanism 30 is operated, the gear portion 36 and the key groove portion 52 are directly meshed with each other so as to transmit the rotational force.
[0078]
This prevents slippage between the pinion 34 and the sleeve 22 during operation of the pretensioner mechanism 30, and in particular prevents time lag and driving force transmission loss until the actual webbing winding starts in the initial operation of the pretensioner mechanism 30. Thus, the initial restraint performance by the pretensioner mechanism 30 is improved.
[0079]
Thus, in the webbing retractor 10 according to the first embodiment, slipping of the clutch that transmits the rotational force of the pinion 34 to the sleeve 22 (spool 14) can be prevented, and the initial restraint performance is improved.
[0080]
Further, in the webbing take-up device 10, when the pretensioner mechanism 30 is operated, the inclined projection 38 and the engagement hole 48 are simply engaged with each other, and the rotational force of the pinion 34 in the arrow A direction is changed to the moving force in the arrow B direction. In order to convert, the clutch which transmits the rotational force of the pinion 34 to the sleeve 22 when the gear part 36 moves in the arrow B direction and meshes with the key groove part 52 is realized with a simple structure.
[0081]
Further, in the webbing take-up device 10, the gear portion 36 is separated from the key groove portion 52 after the pretensioner mechanism 30 is actuated by the biasing force of the leaf spring 50 that normally holds the gear portion 36 at the separated position with respect to the key groove portion 52. Therefore, the pinion 34 and the rack 54 are separated from the spool 14 and do not prevent the spool 14 from rotating in the webbing pull-out direction for energy absorption. That is, when energy is absorbed, a load other than the torsional load of the torsion bar 20 does not act on the webbing 16 (occupant), and appropriate energy absorption is achieved.
[0082]
Furthermore, since the gear part 36 of the rotating body 32 (pinion 34) and the key groove part 52 of the sleeve 22 (spool 14) are directly meshed (coupled) without interposing parts such as rollers, the number of parts is reduced. Reduction is also planned.
[0083]
The present invention is not limited to the webbing take-up device 10 according to the first embodiment. For example, the present invention has a configuration according to a modification as shown in FIG. 6 (A) or FIG. 6 (B). It is also possible to do. Note that components and parts that are basically the same as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and description thereof is omitted.
[0084]
FIG. 6A shows a configuration provided with a compression coil spring 70 as a holding means and an urging means instead of the leaf spring 50. The compression coil spring 70 is disposed so as not to interfere with the gear teeth 36A and the like between the gear portion 36 and the key groove portion 52 in a state where the support shaft portion 22A of the sleeve 22 is inserted. Also with this configuration, the same effect as in the first embodiment can be obtained. Also in this configuration, it is preferable that a bearing is provided at one end or both ends of the compression coil spring 70.
[0085]
FIG. 6B shows a configuration provided with a fitting hole 72 as a driving portion and a fitting shaft 74 as a driven portion in place of the gear portion 36 and the key groove portion 52 in the configuration of FIG. Has been. The fitting hole 72 is a tapered hole with a wide opening end, and its inner surface is knurled. On the other hand, the fitting shaft 74 is a tapered shaft corresponding to the fitting hole, and the outer surface thereof is knurled. When the rotating body 32 in which the fitting hole 72 is formed moves in the direction of the arrow B, the fitting hole 72 and the fitting shaft 74 are guided by the taper of each other and smoothly and reliably fitted, and the pinion 34 rotates. Force is coupled to the sleeve 22 in a transmissible manner.
[0086]
In this configuration, the fitting hole 72 and the fitting shaft 74 that are directly coupled (fitted) are prevented from slipping at the initial stage of coupling due to a wide contact area with each other and a high coefficient of friction due to the knurling finish. The initial restraint performance is improved. Other effects are the same as those of the first embodiment.
[0087]
Thus, the drive part and the driven part in the present invention are not limited to the gear part 36 and the key groove part 52, and any coupling means that can contact and separate in the axial direction can be applied. Therefore, for example, the gear portion 36 or the fitting hole 72 may be provided in the sleeve 22, and the key groove portion 52 or the fitting shaft 74 may be provided in the rotating body 32.
[0088]
Further, in the first embodiment and each modification, the inclined protrusion 38 constituting the coupling means is provided with the tapered portion 38A. However, the present invention is not limited to this, for example, the inclined protrusion 38 Instead of the taper portion 38A or together with the taper portion 38A, a taper portion that is thin on the pinion 34 side (parallel to the taper portion 38A) may be provided on the hole wall on the arrow A side of the engagement hole 48. .
[0089]
Next, a pretensioner mechanism 80 constituting a webbing take-up device according to a second embodiment of the present invention will be described with reference to FIGS. Note that components and portions that are basically the same as those in the first embodiment or modification are given the same reference numerals as in the first embodiment or modification, and descriptions thereof are omitted.
[0090]
As shown in FIG. 7A, the pretensioner mechanism 80 includes a rotating body 82. As shown in FIG. 8, in the rotating body 82, a helical gear 84 as a rotating member and a clutch portion 86 provided with a fitting hole 72 as a driving portion are formed coaxially and integrally. . Further, a support hole 42 is provided through the axial center portion of the rotating body 82 (in communication with the fitting hole 72).
[0091]
Further, the pretensioner mechanism 80 includes a mechanism that applies a rotational force in the direction of arrow A to the helical gear 84. Specifically, the pretensioner mechanism 80 includes a helical rack 88, and one end side of the helical rack 88 is in an assembled state (in an activated state of the pretensioner mechanism 80). Is engaged.
[0092]
The tooth width of the helical rack 88 is sufficiently smaller than the tooth width of the helical gear 84 and meshes with the helical gear 84 on the clutch portion 86 side in the initial state. Although illustration is omitted, a piston 56 is integrally provided on the other end side of the helical rack 88, and the helical rack 88 has an arrow when the gas supply device 60 is operated during a sudden deceleration of the vehicle. It moves in the D direction.
[0093]
The helical gear 84 and the helical rack 88 are the thrust force in the arrow B direction when the helical rack 88 moves in the arrow D direction and rotates the helical gear 84 in the arrow A direction. The inclining direction of the meshing surface is determined so as to occur (the helical gear 84 and the helical rack 88 are formed so as to generate a thrust force in the direction of arrow B). That is, as shown in FIG. 9, the helical rack 88 is formed such that the surface of the tooth D that is inclined with respect to the arrow D direction (the upper side in FIG. 9) faces the arrow B side. It is meshed with a helical gear 84 formed with teeth corresponding thereto.
[0094]
Thereby, the force F transmitted from the helical rack 88 moving in the arrow D direction to the helical gear 84 is the rotational force Fr that rotates the helical gear 84 in the arrow A direction and the arrow B direction. The thrust force Fs is divided and generated. In other words, since the meshing surface of the helical gear 84 and the helical rack 88 is inclined as described above, a part of the force F is directed in the direction of arrow B of the helical gear 84 (rotating body 80). It is converted to the moving force Fs.
[0095]
On the other hand, the sleeve 22 connected to the spool 14 is integrally provided with a fitting shaft 90 as a driven portion corresponding to the fitting hole 72. The fitting shaft 90 is knurled on the outer peripheral surface formed in a taper shape, and has substantially the same configuration as the fitting shaft 74 in the modified example of FIG. 6B, but the tip portion (support shaft portion 22A). A concave portion 92 is formed in the base portion). One end of the compression coil spring 70 is accommodated in the recess 92.
[0096]
In the pretensioner mechanism 80 described above, when the control means operates the gas supply device 60 during a sudden deceleration of the vehicle, the helical rack 88 moves in the D direction while meshing with the helical gear 84. Then, the rotating body 82 moves in the direction of arrow B while rotating in the direction of arrow A by the rotational force Fr and resisting the biasing force of the compression coil spring 70 by the thrust force Fs.
[0097]
As a result, as shown in FIG. 7B, the rotating body 82 (the fitting hole 72 provided in the clutch portion 86) moves in the arrow B direction, and the fitting hole 72 and the fitting shaft 90 are The guides are smoothly and reliably engaged with each other, and the rotational force of the helical gear 84 (rotating body 82) is transmitted to the spool 14 via the sleeve 22. The subsequent operation is the same as that of the first embodiment or the modification described above.
[0098]
In the pretensioner mechanism 80 constituting the webbing take-up device according to the second embodiment, a helical gear 84 as a rotating member for rotating the rotating body 82 (finally the spool 14) rotates. The helical rack 88 that constitutes the drive means also functions as the “coupling means” of the present invention that moves the rotating body 82 in the direction of arrow B, so that the plate 44 or the like in which the engagement holes 48 are formed is unnecessary. As a result, the number of parts is further reduced (significantly compared to the conventional case).
[0099]
Further, in the pretensioner mechanism 80, it is not necessary to provide the disc portion 40 with the inclined projections 38 protruding from the rotating body 82, and the simplification of the structure and the physique (the plate 44 and the disc) together with the reduction in the number of parts. The size of the arrangement space of the portion 40 can be reduced. That is, the webbing take-up device including the pretensioner device 80 can be downsized. Further, with the reduction in the number of parts and the simplification of the structure, the number of assembling steps can be reduced and the assembling workability can be improved, and the webbing take-up device can be reduced in cost.
[0100]
Thus, in the webbing take-up device provided with the pretensioner mechanism 80, the slipping of the clutch that transmits the rotational force of the helical gear 84 to the sleeve 22 (spool 14) can be prevented, and the initial restraint performance is improved. While maintaining the same effects (functions) as in the first embodiment or modification, further reduction in the number of parts, simplification of the structure, size reduction of the physique, and the like are achieved.
[0101]
In each of the above embodiments and modifications, the energy absorption mechanism (lock base 18, lock plate 26, torsion bar 20, etc.) is provided, but the present invention is not limited to this. For example, the webbing retractor 10 may be configured not to absorb energy when the vehicle is suddenly decelerated, or may be configured to include an energy absorbing mechanism other than the torsion bar 20 or the like.
[0102]
In each of the above-described embodiments and modifications, the plate spring 50 or the compression coil spring 70 as the biasing unit is provided as the holding unit. However, the present invention is not limited to this, and for example, the biasing unit. Instead of the means, it may be configured to include a holding member that normally holds the rotating body 32 at a position separated from the sleeve 22 simply by engagement or adhesion.
[0103]
【The invention's effect】
As described above, the webbing take-up device according to the present invention has an excellent effect that the initial restraint performance is improved by preventing or suppressing slipping of the clutch that transmits the rotational force of the rotating member to the take-up shaft.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a schematic overall configuration of a webbing retractor according to a first embodiment of the present invention.
FIG. 2 is a partially cutaway side view showing the webbing retractor according to the first embodiment of the present invention.
3A and 3B are views showing a rotating body constituting the webbing take-up device according to the first embodiment of the present invention, in which FIG. 3A is a perspective view seen from one side in the axial direction, and FIG. It is the perspective view seen from the direction other side.
4 is a schematic cross-sectional view taken along line 4-4 of FIG.
FIG. 5 is a schematic side view showing a relationship between a gear part and a key groove part constituting the webbing take-up device according to the first embodiment of the present invention.
6A is a diagram corresponding to FIG. 4 showing a modification of the urging means, and FIG. 6B is a diagram corresponding to FIG. 4 showing a modification of the drive unit and the driven unit.
7A and 7B are diagrams showing a pretensioner mechanism constituting a webbing take-up device according to a second embodiment of the present invention, in which FIG. 7A is a schematic cross-sectional view showing a clutch disengaged state, and FIG. It is a schematic sectional drawing which shows the coupling state of a clutch.
FIG. 8 is a perspective view showing a rotating body and a helical rack that constitute a webbing take-up device according to a second embodiment of the present invention.
FIG. 9 is a schematic diagram for explaining a force transmitted from a helical rack to a helical gear constituting the webbing take-up device according to the second embodiment of the present invention.
FIG. 10 is a cross-sectional view perpendicular to the axial direction showing a clutch of a conventional pretensioner device.
[Explanation of symbols]
10 Webbing take-up device
12 frames
14 Spool (winding shaft)
16 Webbing
18 Lock base (winding shaft)
20 Torsion bar (winding shaft)
22 Sleeve (winding shaft)
30 Pretensioner mechanism
34 Pinion (Rotating member)
36 Gear part (drive part, clutch)
38 Inclined protrusions (coupling means, engaging part, clutch)
38A Taper (coupling means, clutch)
48 engagement hole (coupling means, engaged portion, clutch)
50 Leaf spring (holding means, biasing means, clutch)
52 Keyway (driven part, clutch)
70 Compression coil spring (holding means, biasing means, clutch)
72 Fitting hole (drive, clutch)
74 Fitting shaft (driven part, clutch)
80 Pretensioner mechanism
84 Helical gear (rotating member, coupling means)
86 Clutch part (drive part, clutch)
88 HASUBA rack (joining means)
90 Fitting shaft (driven part, clutch)

Claims (3)

A winding shaft that is rotatably supported by a frame fixed to the vehicle body, and a webbing for restraining an occupant is wound and withdrawn;
A rotating member provided coaxially with the take-up shaft and rotated in the webbing take-up direction of the take-up shaft at the time of vehicle rapid deceleration;
A clutch that transmits the rotational force of the rotating member to the winding shaft when the rotating member is rotated in the webbing winding direction;
In the webbing take-up device provided with
The clutch is
A driven part integrally provided on the winding shaft;
A driving unit provided integrally with the rotating member and facing the driven unit, and coupled to the driven unit so as to transmit the rotational force when moved in the axial direction;
Provided between the take-up shaft or between said rotary member and said rotary member and said frame as a retaining means for retaining the drive unit to the separated position with respect to the driven part, the said rotary member Urging means for urging the driving unit in a direction away from the driven unit ;
A coupling means for converting a part of the rotational force of the rotating member in the webbing take-up direction into a moving force in the axial direction and coupling the drive unit to the driven unit;
Configured with,
A webbing take-up device characterized by that. The coupling means includes
An engaging portion provided on the rotating member;
An engaged portion that is fixed to the frame and engages with the engaging portion when the rotating member rotates in the webbing winding direction;
And at least one of the engaging portions of the engaging portion and the engaged portion is a tapered portion inclined with respect to the rotation direction of the rotating member.
The webbing take-up device according to claim 1. The rotating member is a helical gear that is rotationally driven by movement of a helical rack that meshes with each other;
The helical gear and the helical rack whose meshing surfaces are inclined in the direction in which the helical gear driven to rotate in the winding direction moves toward the driven part by thrust force, and the coupling means Configured
The webbing take-up device according to claim 1.

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