JP4835281B2 - Webbing take-up device - Google Patents

Description

  The present invention relates to a webbing take-up device applied to a vehicle seat belt device.

  2. Description of the Related Art Conventionally, a webbing take-up device (so-called ELR) having a lock mechanism that prevents a webbing from being pulled out when an occupant-restraining webbing is suddenly pulled out is known. Such a locking mechanism locks the rotation of the take-up shaft by rotating the take-up shaft in the stopped state in the webbing pull-out direction with an acceleration of a predetermined value or more. Further, when the take-up shaft is rotated by a predetermined amount in the webbing take-up direction from this locked state, the lock mechanism releases the lock of the take-up shaft.

  By the way, since the winding shaft is biased in the webbing winding direction by the biasing means, the webbing may be rapidly wound when the occupant releases the mounting of the webbing. When the winding of the webbing is completed in such a state, the rotation of the winding shaft is suddenly stopped, and the lock mechanism may be activated by the acceleration (deceleration acceleration) at the time of the stop. In this case, the webbing is in a fully wound state, and the winding shaft can no longer be rotated in the webbing winding direction, resulting in a problem that it is difficult to release the lock (so-called “end lock”). There is.

Therefore, in order to prevent such an end lock, two pulleys around which the intermediate portion of the webbing is wound are provided in the vicinity of the webbing take-up device, and one pulley is biased in a direction in which the bending angle of the webbing increases. An end lock reduction mechanism having the above-described configuration has been devised (see, for example, Patent Document 1). In this end lock reduction mechanism, when the winding of the webbing is completed, one pulley is displaced against the urging force, so that a resistance force against the winding of the webbing is generated and the winding shaft is decelerated. The acceleration is reduced.
JP 2004-106561 A

  However, the end lock reduction mechanism having the above configuration requires a large installation space because two pulleys, a biasing member, and a holding member thereof must be installed in the vicinity of the webbing take-up device.

  In view of the above facts, an object of the present invention is to provide a webbing take-up device that can reduce the deceleration acceleration of the take-up shaft at the end of winding of the webbing and can save the installation space.

The webbing take-up device according to the first aspect of the invention winds up the occupant-constrained webbing in a layered manner by rotating to one side around the axis, and is directed from the webbing to the other around the axis at the end of the winding. A winding shaft that is stopped by applying a tensile force, and an axis of the winding shaft that is attached to the winding shaft and elastically deformed by the tensile force at the end of the winding to the layered portion of the webbing An elastic body that allows a predetermined amount of relative rotation to one side, the winding shaft and the layered portion provided between the winding shaft and the layered portion, and at the time of relative rotation of the winding shaft with respect to the layered portion And a sliding contact preventing portion that prevents sliding contact with the sliding contact portion .

In the webbing take-up device according to the first aspect, when the take-up shaft is rotated around one axis, the webbing is taken up in layers on the take-up shaft. At the end of the winding, the winding shaft is stopped by applying a tensile force from the webbing toward the other side of the axis. At this time, the elastic body attached to the winding shaft is elastically deformed, thereby allowing a predetermined amount of relative rotation to one side around the axis of the winding shaft with respect to the layered portion of the webbing. Thereby, the deceleration acceleration of the winding shaft is reduced. In addition, since the deceleration acceleration of the winding shaft is reduced by the elastic body attached to the winding shaft in this way, a mechanism for reducing the deceleration acceleration of the winding shaft is installed outside the webbing winding device. There is no need. Therefore, the installation space can be saved. Furthermore, since the sliding contact prevention portion provided between the layered portion of the webbing and the winding shaft prevents sliding contact between the winding shaft and the layered portion, the winding shaft can be smoothly moved with respect to the layered portion. Relative rotation is possible.

  A webbing take-up device according to a second aspect of the invention is characterized in that, in the webbing take-up device according to the first aspect, the elastic body is formed of an elastic material having hysteresis.

  In the webbing take-up device according to the second aspect, since the elastic body does not suddenly return to elasticity, it is possible to suppress the take-up shaft from reversing rapidly around the axis to the other after the take-up shaft stops.

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 , wherein the webbing has a webbing locking hole having one end formed in the take-up shaft. The elastic body is accommodated in the webbing locking hole and inserted into the webbing shaft, and the one end of the webbing and the webbing locking hole are provided when the tensile force is applied. It is characterized by being compressed between the inner walls.

In the webbing take-up device according to claim 3, when a tensile force is applied to the take-up shaft from the webbing to the other side around the axis, the webbing take-up device is inserted into the webbing engagement hole of the take-up shaft and engaged with the take-up shaft. The elastic body is compressed and elastically deformed between one end of the stopped webbing and the inner wall of the webbing locking hole. Since this elastic body is accommodated in the webbing engagement hole, it is possible to suppress an increase in the size of the winding shaft due to the space for mounting the elastic body.

  As described above, in the webbing take-up device according to the present invention, it is possible to reduce the deceleration acceleration of the take-up shaft at the end of the webbing take-up and to reduce the installation space.

  FIG. 1 is a front sectional view showing a schematic overall configuration of a webbing take-up device 10 according to an embodiment of the present invention.

  The webbing retractor 10 according to the present embodiment is a so-called ELR (emergency locking retractor), and includes a frame 12. The frame 12 includes a substantially plate-like back plate 14. The back plate 14 is fixed to the vehicle body by fastening means (not shown) such as bolts, so that the webbing take-up device 10 is attached to the vehicle body. ing. A pair of leg plates 16 and 18 extend in parallel from both ends of the back plate 14 in the width direction, and a spool 20 as a take-up shaft manufactured by die casting or the like is rotatable between the leg plates 16 and 18. Is arranged. The spool 20 includes a cylindrical spool body 22 and a pair of flange portions 24 and 26 formed at both axial ends of the spool body 22.

  As shown in FIG. 2, a webbing engagement hole 28 is formed in the spool body 22. The webbing locking hole 28 is formed in a slit shape that is long along the axial direction of the spool body 22, and an opening 28 </ b> A that opens on both sides along the radial direction of the spool body 22 at the outer peripheral portion of the spool body 22. , 28B. These openings 28 </ b> A and 28 </ b> B are formed in a wedge shape in cross section, and the webbing engagement hole 28 has a reduced cross-sectional area at an intermediate portion along the radial direction of the spool body 22.

  A free plate 30 (not shown in FIG. 1) made of a thin plate of elastic resin material or spring material is attached to the outer peripheral portion of the spool body 22. As shown in FIG. 3, the free plate 30 has a cylindrical portion 30 </ b> A as a sliding contact prevention portion formed in a C-shaped cylindrical shape, and the cylindrical portion 30 </ b> A is an outer periphery of the spool body 22. Coaxially wrapped around the part. One end of the cylindrical portion 30A in the bending direction (the end on one side around the axis of the spool body 22 and the end on the arrow A side in FIG. 2) protrudes radially inward of the cylindrical portion 30A. An insertion portion 30B as an elastic body is provided. As shown in FIG. 2, the insertion portion 30 </ b> B is inserted into the webbing locking hole 28 from one opening 28 </ b> A of the webbing locking hole 28. For this reason, the free plate 30 basically rotates together with the spool 20, but the base end side (the upper side in FIG. 2) of the insertion portion 30 </ b> B is elastically deformed, so that the cylindrical portion 30 </ b> A is axial with respect to the spool 20. It can be rotated relative to the other side (in the direction of arrow B in FIG. 2) by a predetermined amount.

  As shown in FIG. 4, a space surrounded by the cylindrical portion 30 </ b> A and the insertion portion 30 </ b> B of the free plate 30 and the inner wall of the opening 28 </ b> A is formed in one opening 28 </ b> A of the webbing locking hole 28. ing. This space is formed in a triangular shape when viewed from the axial direction of the spool body 22, and rubber 32 (for example, EPDM (ethylene propylene rubber) or the like) as an elastic body is provided in this space. As shown in FIG. 5, the rubber 32 is formed in a triangular prism shape and has hysteresis. In addition, urethane foam etc. can also be used as an elastic body.

  Further, in the webbing engagement hole 28, one end in the longitudinal direction of the webbing 34 for restraining the passenger formed in a long band shape is inserted from the one opening 28A side. One end of the webbing 34 in the longitudinal direction is wound around a shaft 36 provided in the other opening 28B of the webbing locking hole 28 and folded, and the portions before and after the winding are sewn together. The hook portion cannot pass through the intermediate portion of the webbing locking hole 28 along the radial direction of the spool body 22. Thereby, one end of the webbing 34 in the longitudinal direction is locked to the spool 20.

  For this reason, when the spool 20 is rotated around one of its axes (in the direction of arrow A in FIG. 2, this direction is hereinafter referred to as “winding direction” for convenience), the webbing 34 is free from the one end side in the longitudinal direction. It is wound up in layers on the outer periphery of 30A. When the webbing 34 is pulled from the other end in the longitudinal direction, the webbing 34 wound around the outer peripheral portion of the spool body 22 is pulled out from the webbing take-up device 10, and the spool 20 is rotated around the axis to the other side. (Hereinafter, the rotation direction of the spool 20 when pulling out the webbing 34 will be referred to as “drawing direction” for convenience). The other end in the longitudinal direction of the webbing 34 is locked to the vehicle body, for example, on the side of the vehicle seat.

  On the other hand, a case 38 is attached to the outside of the leg piece 16 of the frame 12. A spiral spring 40 is accommodated in the case 38. In the spiral spring 40, the end on the outer side in the spiral direction is locked to the case 38, and the end on the inner side in the spiral direction is locked to the spool 20. The spiral spring 40 biases the spool 20 in the winding direction. For this reason, when the tension applied to the webbing 34 to be pulled out from the spool 20 is released, the urging force of the spiral spring 40 rotates the spool 20 in the winding direction so that the webbing 34 is wound around the spool 20. Yes.

  Here, when the webbing 34 drawn out from the webbing take-up device 10 has taken up the entire drawing amount, and the webbing 34 can no longer be taken up (when the winding of the webbing 34 is finished), the spool 20 is stopped by being given a pulling force from the webbing 34 in the pulling direction. At this time, the spool 20 tends to rotate relative to the layered portion 34A of the webbing 34 wound around the outer periphery of the free plate cylindrical portion 30A in the winding direction (the direction of arrow A in FIG. 2). One end in the longitudinal direction of the webbing 34 inserted into the webbing locking hole 28 presses the proximal end side of the insertion portion 30B of the free plate 30 in the pulling direction (the direction of arrow B in FIGS. 2 and 4), and the insertion portion 30B. And the rubber 32 is compressed between the insertion portion 30B and the inner wall of the one opening 28A. As a result, as shown in FIG. 6, the rubber 32 is elastically deformed, and a predetermined amount of relative rotation in the winding direction of the spool 20 with respect to the layered portion 34A of the webbing 34 is allowed.

  On the other hand, a lock mechanism 42 is disposed outside the leg piece 18 of the frame 12. This locking mechanism 42 is configured to detect (accelerate) the rotation of the spool 20 in the pull-out direction instantaneously by detecting the acceleration in the vehicle emergency or when the webbing 34 is pulled out suddenly. Further, when the spool 20 is rotated in the winding direction by a predetermined amount in this locked state, the lock of the spool 20 by the lock mechanism 42 is released.

  Next, the operation of this embodiment will be described.

  In the webbing retractor 10 having the above-described configuration, when the occupant seated on the vehicle seat pulls the webbing 34 in the retracted state in which the webbing 34 is wound around the outer peripheral portion of the free plate cylindrical portion 30A, the spool 20 The webbing 34 is pulled out while rotating in the pulling direction. As a result, the occupant can hang the webbing 34 around the body and, for example, engage the tongue plate provided on the webbing 34 with the buckle device to attach the webbing 34 to the body.

  On the other hand, when the occupant releases the engagement state between the tongue plate and the buckle device, the spool 20 is rotated in the winding direction by the biasing force of the spiral spring 40, and the webbing 34 is rotated from one end in the longitudinal direction to the outer periphery of the free plate cylindrical portion 30A. The film is wound up in layers. Then, when the webbing 34 is wound up by the entire amount of withdrawal, and the winding of the webbing 34 is completed, the spool 20 is stopped by being given a tensile force directed from the webbing 34 in the withdrawal direction.

  At this time, since the spool 20 tends to rotate relative to the layered portion 34A of the webbing 34 in the winding direction, one end in the longitudinal direction of the webbing 34 inserted into the webbing engagement hole 28 of the spool 20 is the free plate 30. The insertion portion 30B is pressed in the pulling direction so that the insertion portion 30B is elastically deformed in the pulling direction, and the rubber 32 is compressed between the insertion portion 30B and the inner wall of the webbing locking hole 28 to be elastically deformed. To do. Therefore, the spool 20 is stopped after being relatively rotated by a predetermined amount while being gradually attenuated with respect to the layered portion 34A inside the free plate 30. Thereby, since the deceleration acceleration of the spool 20 is reduced, the malfunction of the lock mechanism 42 due to the sudden stop of the spool 20 can be suppressed, and the occurrence of end lock can be suppressed.

  Moreover, in the webbing take-up device 10, the rubber 32 is provided in the webbing engagement hole 28 of the spool 20, and the free plate 30 is formed in a thin cylindrical shape and is coaxial with the outer peripheral portion of the spool body 22. Therefore, the overall configuration of the webbing take-up device 10 is not increased by the mounting space for the rubber 32 and the free plate 30. Therefore, the installation space can be saved.

  Moreover, since it is a simple structure which only adds two components, the rubber | gum 32 and the free plate 30, with respect to general ELR, generation | occurrence | production of an end lock can be suppressed at low cost.

  Further, in the webbing take-up device 10, since the rubber 32 is formed of an elastic material having hysteresis and does not suddenly return to elasticity, the spool 20 is suddenly reversed in the drawing direction after stopping. In addition, it is possible to suppress the end lock because the occupant can pull the webbing 34 to increase the amount of rotation of the spool 20 in the winding direction in the event that an end lock occurs. Become.

  Furthermore, in the webbing take-up device 10, the cylindrical portion 30A of the free plate 30 provided between the layered portion 34A of the webbing 34 and the spool 20 prevents sliding contact between the spool 20 and the layered portion 34A. Therefore, the spool 20 can be smoothly rotated relative to the layered portion 34A.

  In the webbing retractor 10 according to the above-described embodiment, the free plate 30 includes the cylindrical portion 30A as the sliding contact preventing portion. However, the present invention is not limited to this, and the friction coefficient of the outer peripheral portion of the spool body 22 is not limited thereto. Is small, the cylindrical portion 30A may be omitted when the layered portion 34A of the webbing 34 can smoothly rotate relative to the spool 20.

  Moreover, in the webbing retractor 10 according to the above-described embodiment, it is configured to include two elastic bodies, that is, the insertion portion 30B of the free plate 30 and the rubber 32, but this is not a limitation, and either one is omitted. Also good.

  Further, in the webbing take-up device 10 according to the above-described embodiment, the rubber 32 as an elastic body is provided in the webbing engagement hole 28 of the spool body 22 and is compressed along the circumferential direction of the spool body 22. However, the configuration is not limited thereto, and an elastic body may be attached to the outer peripheral portion of the spool body 22 and compressed along the radial direction of the spool body 22. In addition, a cylindrical member is attached to the outside of the spool 20 so as to be coaxial and relatively rotatable, and one end portion of the webbing 34 in the longitudinal direction is locked to the cylindrical member, and between the cylindrical member and the spool 20. It is good also as a structure which provides an elastic body.

1 is a front sectional view showing a schematic overall configuration of a webbing take-up device according to an embodiment of the present invention. It is sectional drawing which shows the structure of the spool of the webbing winding apparatus which concerns on embodiment of this invention. It is a perspective view which shows the structure of the free plate attached to the spool of the webbing take-up device according to the embodiment of the present invention. It is an expanded sectional view showing composition of a principal part of a spool of a webbing take-up device concerning an embodiment of the present invention. It is a perspective view which shows the structure of the rubber attached to the spool of the webbing take-up device according to the embodiment of the present invention. It is an expanded sectional view corresponding to Drawing 4 showing the state where the free plate and rubber concerning an embodiment of the present invention elastically deformed.

Explanation of symbols

10 Webbing take-up device 20 Spool (winding shaft)
28 Webbing engagement hole 30 Free plate 30A Tubular part (sliding contact prevention part)
30B Insertion part (elastic body)
32 Rubber (elastic body)
34 Webbing 34A Layered part

Claims (3)

Winding the webbing for restraining the occupant in a layered manner by rotating to one side around the axis, and at the end of winding, a winding shaft that is stopped by being given a tensile force from the webbing to the other around the axis;
An elastic body attached to the take-up shaft and elastically deformed by the tensile force at the end of the take-up, thereby allowing a predetermined amount of relative rotation to one side around the axis of the take-up shaft with respect to the layered portion of the webbing; ,
A sliding contact preventing portion provided between the winding shaft and the layered portion, the sliding shaft preventing the sliding shaft and the layered portion from slidingly contacting each other when the winding shaft rotates relative to the layered portion;
A webbing take-up device comprising:   The webbing retractor according to claim 1, wherein the elastic body is made of an elastic material having hysteresis. One end of the webbing is inserted into a webbing locking hole formed in the winding shaft and locked to the winding shaft, and the elastic body is accommodated in the webbing locking hole, webbing retractor according to claim 1 or claim 2, characterized in Rukoto is compressed between the inner wall of the end portion of the webbing when the pulling force of applying the webbing locking hole.

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