JP2019166900A - Seat belt device - Google Patents

Abstract

To provide a seat belt device in which a variably restricting range of tension acting on a webbing is widened.SOLUTION: A retractor 2 includes: a spool 21 winding up a webbing 1; a lock wheel 22 rotatably mounted on one side of the spool 21 in an axial direction; and a lock wheel locking member 28 inhibiting rotation of the lock wheel 22 under a predetermined condition. Further, in the retractor: one outer end part 211 of the spool 21 includes a friction plate contact part 211b; the lock wheel 22 includes a cylindrical part 221 into which the one outer end part 211 is inserted; and between an outer peripheral surface of the one outer end part 211 and an inner peripheral surface of the cylindrical part 221, there are arranged a friction plate 31 and a spring 32, and a nut 26 absorbing rotation energy of the spool 21 in cooperation with the friction plate 31 and a spring 32, while rotating in the axial direction in accompany with rotation of the spool 21 after an ELR mechanism action.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a seat belt device installed in a vehicle such as an automobile.

  The seat belt device is a safety device that protects the occupant by preventing the occupant from jumping out of the seat, and includes a webbing that restrains the occupant to the seat, and a length that allows the webbing to be pulled out by storing part or all of the webbing ( And a retractor capable of adjusting the webbing withdrawal amount).

  The retractor includes an ELR (Emergency Locking Retractor) mechanism that locks the webbing drawer. The ELR mechanism protects the occupant by preventing the occupant from jumping out of the seat by locking the webbing drawer when a large acceleration or deceleration is applied to the vehicle body (for example, when the vehicle collides). is there.

  Further, the retractor is provided with an EA (Energy Absorber) mechanism that limits the tension (webbing tension) acting on the webbing when the ELR mechanism is operated. The EA mechanism allows the webbing to be pulled out so that the webbing tension (the tension of the webbing that restrains the occupant) does not exceed a predetermined value, and the webbing is pulled out from the retractor with the predetermined webbing tension (webbing pull-out). ) To reduce the impact load acting on the occupant by absorbing the kinetic energy in the meantime.

  Further, in recent years, a variable EA mechanism that variably limits the webbing tension has been developed in order to realize various energy absorption characteristics when the ELR mechanism is operated (see, for example, Patent Documents 1-6). The variable EA mechanism is a mechanism in which a separate mechanism (second EA mechanism) is additionally provided in addition to the EA mechanism (first EA mechanism) described above, and the retractor is retracted with a predetermined webbing tension by the first EA mechanism. The webbing pulled out from the vehicle is further subjected to a temporary load by the second mechanism to temporarily increase the webbing tension (to further limit the webbing withdrawal), thereby further absorbing the kinetic energy and the occupant This further reduces the impact load acting on the.

JP 2002-53007 A JP 2000-85527 A JP 2002-53008 A Japanese Patent Laid-Open No. 10-258702 Japanese Patent Laid-Open No. 2001-106025 JP 2002-59809 A

  However, in the prior art, the range in which the webbing tension can be increased by the second EA mechanism (webbing withdrawal amount) is shorter than the webbing withdrawal amount drawn by the first EA mechanism. Not enough to realize. For example, in the prior art described in Patent Documents 1-6, due to its configuration, the range from the start of webbing withdrawal after the ELR mechanism is actuated to the rotation of the spool (webbing take-up portion) about one revolution (webbing) The webbing tension can be increased (variable) only by the amount of withdrawal).

  The present invention has been made in view of the above problems, and an object thereof is to widen a range in which the tension acting on the webbing in the seat belt device can be variably limited.

  A seatbelt device according to a first invention for solving the above-mentioned problems is a seatbelt device comprising a webbing for restraining an occupant to a seat, and a retractor capable of adjusting a pull-out amount of the webbing, wherein the retractor A first rotating body that is rotatably supported by a retractor frame fixed to the vehicle body and winds up the webbing, and is disposed on one end side in the axial direction of the first rotating body. A second rotating body rotatably supported by the retractor frame together with a body, and a lock device for preventing rotation of the second rotating body under a predetermined condition, The body has a cylindrical portion into which one axial end side of the first rotating body is inserted, and a contact portion provided between the first rotating body and the cylindrical portion and extending along the radial direction; And the first rotating body The first rotating body is interposed between the cylindrical portion and opposed to the axial end surface of the contact portion, and the second rotating body is prevented from rotating by the locking device. A contact member that rotates relative to the contact portion when a rotational force is applied, and an outer peripheral surface on one end side in the axial direction of the first rotating body and an inner peripheral surface of the cylindrical portion. When a force in the rotational direction acts on the first rotating body in a state where the rotation of the second rotating body is prevented by the locking device, the axial direction is accompanied by the rotation of the first rotating body. A sliding member that moves between the contact member and the sliding member in a contracted state when the second rotating body is rotatable and has an elastic force in the axial direction. And an elastic body interposed.

  The seat belt device according to a second aspect of the present invention is the seat belt device according to the first aspect, wherein the contact portion is formed on the first rotating body, and the contact member moves the cylindrical portion in the rotational direction. It is supported in a regulated state.

  The seat belt device according to a third aspect of the present invention is the seat belt device according to the second aspect of the present invention, wherein the first threaded portion formed on the outer peripheral surface on the one axial end side of the first rotating body, A second screw part formed on a peripheral surface and screwed into the first screw part, wherein the sliding member is restricted from moving in the rotational direction with respect to the cylindrical part. To do.

  According to a fourth aspect of the present invention, there is provided a seat belt device according to the third aspect of the invention, wherein the sliding member is a nut supported so as to be integrally rotatable with the cylindrical portion and movable in the axial direction. Is fastened to a first screw portion formed on an outer peripheral surface on one axial end side of the first rotating body to press the elastic body toward the contact member, and the locking device causes the first When a rotational force is applied to the first rotating body in a state where the rotation of the second rotating body is blocked, the second rotating body moves in a direction away from the contact member as the first rotating body rotates. It is characterized by that.

  According to the seat belt device of the present invention, it is possible to widen the range in which the tension acting on the webbing in the seat belt device can be variably limited, and to restrain the occupant in cooperation with the airbag. The restraining force can be kept low.

FIG. 2 is a front view illustrating a main part of the seat belt device according to the embodiment of the present invention with a part thereof broken away. It is the elements on larger scale of FIG. It is sectional drawing which shows typically the III-III part of FIG. It is sectional drawing which shows the IV-IV part of FIG. 1 typically. It is explanatory drawing which shows the operation | movement at the time of the variable EA mechanism action | operation of the seatbelt apparatus in embodiment of this invention. It is explanatory drawing which shows the operation | movement following FIG. 5A at the time of variable EA mechanism operation | movement of the seatbelt apparatus in embodiment of this invention. It is explanatory drawing which shows the operation | movement following FIG. 5B at the time of variable EA mechanism operation | movement of the seatbelt apparatus in embodiment of this invention. It is a graph which shows the relationship between a passenger | crew's front deviation by a seatbelt apparatus concerning this embodiment, and a passenger | crew chest restraint force. It is a graph which shows the relationship between passenger | crew forward deviation and passenger | crew chest restraint force by the seatbelt apparatus provided with the EA mechanism using only the conventional torsion bar. It is a graph which shows the relationship between a passenger | crew's forward deviation and passenger | crew chest restraint force by the seatbelt apparatus provided with the conventional variable EA mechanism. It is a front view which shows a partially broken main part of another example of the seat belt device according to the present invention.

  Hereinafter, an embodiment of a seat belt device according to the present invention will be described with reference to FIGS.

  The seat belt device according to the present embodiment shown in FIG. 1 is a safety device that is mounted on a vehicle such as an automobile and prevents the occupant from jumping out of the seat and protects the occupant. The retractor 2 is a winding device capable of adjusting the amount of the webbing 1 drawn out.

  In the present embodiment, the retractor 2 includes a spool 21, a lock wheel 22, and an ELR wheel 23 as shown in FIGS. 1 to 4.

  The spool 21 is formed in a substantially cylindrical shape and is rotatably supported by a retractor frame 25 fixed to the vehicle body. The spool 21 has a larger diameter at both ends in the axial direction than the portion where the webbing 1 is wound. Hereinafter, the part formed in this large diameter is called the outer end part 211,212.

  In the present embodiment, one outer end 211 has a smaller outer diameter than the other outer end 212. The one outer end portion 211 has a male threaded portion 211a as a first threaded portion, and is formed on the axially inner end of the male threaded portion 211a over the circumferential direction and protrudes radially outward. It has a flange portion (hereinafter referred to as a friction plate contact portion) 211b as a contact portion.

  The male screw portion 211a is inserted through a friction plate 31 as a contact member and a spring (spring) 32 as an elastic body in order. A nut 26 as a sliding member is screwed to the male screw portion 211a.

  The friction plate 31 has an outer peripheral shape of a hexagonal shape in sectional view and an inner peripheral shape of a circular shape in sectional view. The inner diameter of the friction plate 31 is smaller than the outer diameter of the friction plate contact portion 211b, and the friction plate 31 is configured such that the end surface on the inner side in the axial direction is in contact with the friction plate contact portion 211b.

  The spring 32 is disposed so as to be able to expand and contract in the axial direction (so as to have an elastic force). The spring 32 has a diameter larger than the inner diameter of the friction plate 31 and smaller than the outer diameter, and is configured to contact the end surface of the friction plate 31 on the outer side in the axial direction.

  The nut 26 has a hexagonal shape in section when the outer peripheral shape is substantially the same as that of the friction plate 31, and the maximum diameter of the female screw portion 26 a as the second screw portion (the diameter of the valley portion) is the maximum of the male screw portion 211 a. Is substantially equal to the diameter (diameter of the thread), and is smoothly screwed into the male screw portion 211a.

  When the spool 21 rotates relative to the nut 26 in the webbing pull-out direction, the nut 26 is guided by the male screw portion 211a and moves outward in the axial direction. It is assumed that That is, in the normal state, the spring 32 is contracted, and the friction plate 31 is pressed against the friction plate contact portion 211b by the elastic force of the spring 32.

  The lock wheel 22 is formed in a bottomed cylindrical shape, is disposed on one axial end side (the left side in FIGS. 1 and 2) of the spool 21, and is rotatably supported by the retractor frame 25. When the belt withdrawal acceleration detector 27 detects that the belt withdrawal acceleration exceeds a predetermined value, the lock wheel 22 generates a relative rotational force in the webbing withdrawal direction with respect to the ELR wheel 23. The rotation is prevented by the lock wheel lock member 28 at the time.

  The cylindrical portion 221 of the lock wheel 22 has a circular outer shape on the outer peripheral surface and a hexagonal shape on the inner peripheral surface that is substantially the same as the outer peripheral shape of the friction plate 31 and the nut 26. One outer end portion 211 is inserted into the hollow portion of the tubular portion 221 together with the friction plate 31, the spring 32, and the nut 26 described above. Here, since the inner peripheral surface of the cylindrical portion 221 and the outer peripheral shapes of the nut 26 and the friction plate 31 are substantially the same hexagonal shape, the nut 26 and the friction plate 31 are pivoted with respect to the cylindrical portion 221. On the other hand, the movement is restricted in the rotational direction (in other words, the state is supported so as to be integrally rotatable with the cylindrical portion 221). In other words, in the retractor 2, the friction plate 31 is pressed against the friction plate contact portion 211 b by the nut 26 via the spring 32, thereby rotating between the spool 21 and the lock wheel 22 via the friction plate 31. Movement (rotational force) is transmitted.

  The ELR wheel 23 is formed in a generally disc shape and is disposed on one end side in the axial direction of the lock wheel 22, and is supported on the retractor frame 25 so as to be rotatable together with the lock wheel 22. The ELR wheel 23 is configured to be prevented from rotating by the ELR wheel lock member 30 when the vehicle body acceleration detection unit 29 detects that the vehicle body acceleration exceeds a predetermined value.

  Here, in this embodiment, the ELR mechanism is configured by the lock wheel 22, the ELR wheel 23, the belt withdrawal acceleration detection unit 27, the lock wheel lock member 28, the vehicle body acceleration detection unit 29, the ELR wheel lock member 30, and the like. The variable EA mechanism is configured by the spool 21, the lock wheel 22, the nut 26, the friction plate 31, the spring 32, and the like.

  Hereinafter, the operation of the seat belt device according to the present embodiment will be described.

  First, for example, when a large deceleration is applied to the vehicle, the ELR wheel lock member 30 prevents the ELR wheel 23 from rotating when the vehicle body acceleration detection unit 29 detects a sudden deceleration of the vehicle. At this time, the occupant tends to move relative to the vehicle body due to inertia, and the kinetic energy acts on the webbing 1 restraining the occupant, and a load in the pulling direction is applied to the webbing 1.

  When a load in the pulling direction is applied to the webbing 1 in a state where the rotation of the ELR wheel 23 is blocked, this load is transmitted to the lock wheel 22 via the spool 21 and the friction plate 31, and is transmitted to the lock wheel 22 with respect to the ELR wheel 23. A relative rotational force in the webbing pull-out direction is generated, and the lock wheel lock member 28 prevents the lock wheel 22 from rotating in the webbing pull-out direction.

  As described above, when the rotation of the lock wheel 22 in the webbing pull-out direction is prevented, the friction plate 31 that is restricted from moving in the rotational direction with respect to the cylindrical portion 221 is prevented from rotating. The friction plate 31 that does not rotate is pressed against the friction plate contact portion 211b by the spring 32, while the spool 21 (friction plate contact portion 211b) maintains a rotatable state.

  Therefore, when a larger load in the pulling direction is applied to the webbing 1 in a state where the rotation of the ELR wheel 23 and the lock wheel 22 is blocked, it is generated between the friction plate contact portion 211b to rotate and the friction plate 31 that does not rotate. The spool 21 starts to rotate against the frictional force.

  When the spool 21 starts to rotate, as shown in FIG. 5A, the nut 26 is guided by the male screw portion 211a and starts to move in the axial direction. When the nut 26 moves in the axial direction, the pressing force applied to the friction plate 31 by the spring 32 gradually decreases (see FIG. 5B), and accordingly, the frictional force between the friction plate contact portion 211b and the friction plate 31 is reduced. Reduce gradually. Then, as shown in FIG. 5C, when the nut 26 moves to a position where the spring 32 becomes a free length, the frictional force between the friction plate contact portion 211b and the friction plate 31 becomes zero.

  Therefore, according to the seat belt device according to the present embodiment, when the spool 21 starts to rotate in the webbing pull-out direction after the ELR mechanism is operated, the spool 21 is caused by the frictional force generated between the friction plate contact portion 211b and the friction plate 31. During about two rotations, the nut 26, the friction plate 31 and the spring 32 cooperate to provide resistance (load) to the rotation of the spool 21 and absorb the rotational energy of the spool 21. The range in which the tension acting on 1 can be variably limited can be made wider than before.

  Further, in the event of a vehicle collision or the like, the occupant (especially the occupant's chest) is restrained by the cooperation of the webbing 1 and an air bag (not shown), so the load applied to the occupant's chest (occupant chest restraint force) It is the sum of the reaction force of the airbag. It is known that the airbag is often a linear spring, and in a general seat belt device, the restraining force by the webbing 1 increases as the occupant is displaced forward, and the probability of occurrence of injury to the occupant increases.

  In contrast, in the present embodiment, as shown in FIG. 6A, the frictional force generated between the friction plate contact portion 211b and the friction plate 31 is gradually reduced as the spool 21 rotates. The webbing tension F1 can be lowered as the frontal displacement of the occupant increases with respect to the reaction force F2 of the airbag that increases as the forward displacement of the occupant increases, thereby suppressing the occupant chest restraint force F3 to a low level. And the probability of injury occurrence can be reduced.

  On the other hand, in the EA mechanism using the conventional torsion bar and the variable EA mechanism as described in Patent Documents 1 to 6, as shown in FIGS. 6B and 6C, respectively, the maximum value of the occupant chest restraint force F3 is shown. However, there is a possibility that the probability of injury occurrence is higher than that of the present embodiment.

  The webbing pull-out restriction by the nut 26, the friction plate 31, and the spring 32 may be set according to the characteristics of the vehicle to be applied (the position of the steering wheel, the structure of the airbag, etc.).

  For example, if the elastic force of the spring 32 is reduced, the amount of webbing tension to be increased can be reduced, and if the elastic force of the spring 32 is increased, the amount of webbing tension to be increased can be increased.

  The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

  For example, the nut 26 and the friction plate 31 can move in the axial direction with respect to the cylindrical portion 221, but the outer peripheral shape may not be hexagonal as long as the movement can be restricted with respect to the rotation direction.

  Further, in the above-described embodiment, an example in which the outer diameter of one outer end portion 211 is smaller than the outer diameter of the other outer end portion 212 is shown, but the outer diameter of one outer end portion 211 is the other outer end. The outer diameter of the portion 212 may be the same as or larger than the outer diameter of the other outer end portion 212.

  In the above-described embodiment, the example in which the nut 26 and the friction plate 31 are supported by the cylindrical portion 221 is shown. However, as shown in FIG. A friction plate contact portion 221b extending radially inward along the circumferential direction is formed on the outer side in the axial direction of the female screw portion 221a, and the outer end portion 211 can be integrally rotated and moved in the axial direction. The annular member 33 and the friction plate 31 are supported so that a male screw portion 33 a is formed on the outer periphery of the annular member 33, and a spring 32 is interposed between the annular member 33 and the friction plate 31. May be. Even if it is a case where it is such a structure, the effect similar to embodiment mentioned above can be acquired.

  In the above-described embodiment, an example in which the nut 26 slides outward in the axial direction as the spool 21 rotates is shown. However, the nut 26 slides inward in the axial direction as the spool 21 rotates. May be. However, in this case, it is necessary to add a member so that the nut 26 does not jump out of the cylindrical portion 221.

  Further, as shown by a one-dot chain line in FIG. 1, the torsion is inserted into the spool 21, one end is fixed to the bottom portion 222 of the lock wheel 22, and the other end is fixed to the other outer end portion 212 of the spool 21. You may add a bar.

  In the above-described embodiment, the example in which the spring 32 is used as the elastic body has been described. However, the elastic body is not limited to the spring 32, and the friction plate 31 can be pressed against the friction plate contact portion 211b by tightening the nut 26. Other members may be used if possible.

DESCRIPTION OF SYMBOLS 1 Webbing 2 Retractor 21 Spool 22 Lock wheel 23 ELR wheel 25 Retractor frame 26 Nut 26a Female thread part 27 Belt extraction acceleration detection part 28 Lock wheel lock member 29 Car body acceleration detection part 30 ELR wheel lock member 31 Friction plate 32 Spring 33 Annular member 33a Male thread part 211, 212 Outer end part 211a Male thread part 211b Friction plate contact part 221 Cylindrical part 221a Female thread part 221b Friction plate contact part 222 Bottom part

Claims (4)

In a seat belt device comprising a webbing for restraining an occupant to a seat, and a retractor capable of adjusting a pull-out amount of the webbing,
The retractor is
A first rotating body that is rotatably supported by a retractor frame fixed to the vehicle body and winds up the webbing;
A second rotating body disposed on one axial end side of the first rotating body and rotatably supported by the retractor frame together with the first rotating body;
A locking device that prevents rotation of the second rotating body under predetermined conditions,
The second rotating body has a cylindrical portion for inserting one axial end side of the first rotating body,
A contact portion provided between the first rotating body and the cylindrical portion and extending along a radial direction;
In a state of being interposed between the first rotating body and the tubular portion and facing the axial end surface of the contact portion, the rotation of the second rotating body is prevented by the locking device. A contact member that rotates relative to the contact portion when a rotational force is applied to the first rotating body;
The first rotating body is interposed between an outer peripheral surface on one axial end side of the first rotating body and an inner peripheral surface of the cylindrical portion, and the second rotating body is prevented from rotating by the locking device. A sliding member that moves in the axial direction along with the rotation of the first rotating body when a rotational force is applied to the one rotating body;
An elastic body having an elastic force with respect to the axial direction and interposed between the contact member and the sliding member in a contracted state when at least the second rotating body is rotatable;
A seat belt device comprising: The contact portion is formed on the first rotating body;
The seat belt device according to claim 1, wherein the contact member is supported by the cylindrical portion in a state in which movement in a rotation direction is restricted. A first threaded portion formed on the outer peripheral surface on one axial end side of the first rotating body;
A second screw portion formed on the inner peripheral surface of the sliding member and screwed into the first screw portion;
The seat belt device according to claim 2, wherein the sliding member is restricted from moving in the rotational direction with respect to the cylindrical portion. The sliding member is a nut supported to be rotatable integrally with the cylindrical portion and movable in the axial direction;
The nut is fastened to a first screw portion formed on an outer peripheral surface on one end side in the axial direction of the first rotating body, thereby pressing the elastic body toward the abutting member, and by the locking device When a rotational force is applied to the first rotating body in a state in which the rotation of the second rotating body is blocked, the first rotating body moves away from the contact member along with the rotation of the first rotating body. The seat belt device according to claim 3, wherein the seat belt device moves.

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