JP4647435B2 - Seat belt retractor - Google Patents

Description

  The present invention relates to a seatbelt retractor, and more particularly to a seatbelt retractor that can prevent a webbing from being rapidly wound by a spool when a tongue engaged with a buckle is disengaged. .

  In a retractor for a seat belt provided in an automobile vehicle, when the engagement between the tongue and the buckle is released, the webbing is wound around a spool provided in the retractor.

  At that time, the winding speed is accelerated as the webbing is wound. Therefore, since the tongue is also drawn toward the retractor suddenly, there has been a problem in that it collides with an automobile occupant or collides with a member in the automobile such as a trim to damage them. Also, ELR (Emergency Locking Retractor) is capable of winding and withdrawing the webbing at normal times, and instantly preventing the spool from rotating in the webbing withdrawal direction by the locking means in case of vehicle emergency or sudden webbing withdrawal. When the winding is completed due to the rapid winding of the webbing, the rotation of the spool is abruptly stopped, and the state is the same as the state where the webbing is rapidly pulled out. As a result, there has been a problem (end lock) that it is difficult to release the locking means.

  In order to eliminate such inconvenience, the webbing pulled out from the retractor is wound around the fixed pulley and the moving pulley, and when the webbing is wound up by the retractor, the moving pulley moves so that the webbing winding force is applied. It has been proposed to generate a resistance force and prevent the webbing from being taken up rapidly (for example, see Patent Document 1).

Furthermore, means for using a retractor with a weak biasing force as a spring for rotating the spool in the retractor, and means for reducing the winding force of the webbing by the spool by always contacting a member having a rough surface with the webbing. ing.
JP 2004-106561 A

  However, the method of reducing the webbing take-up force by providing the fixed pulley and the moving pulley proposed in Patent Document 1 always causes resistance even when the webbing is pulled out from the retractor, and this impedes the belt mounting property. The problem arises.

  Further, when a spring having a weak urging force is used, there arises a problem that the urging force cannot be secured due to the sag of the spring due to long-term use of the retractor. Further, in the means for reducing the webbing take-up force by the spool by constantly contacting a member having a rough surface with the webbing, the contacted part is worn out in a short period of time, or the resistance to the webbing is always constant. As a result, there is a problem that the belt wearability is hindered.

  An object of the present invention is to provide a seatbelt retractor that can smoothly and reliably wind up webbing without hindering the belt mountability.

In order to solve the above-described problems, according to the invention described in claim 1, the webbing take-up unit that winds the webbing is provided at both ends of the webbing take-up unit and the webbing take-up unit that is rotatably supported by the housing by the rotating shaft. A retractor for a seat belt comprising: a spool provided with a flange extending radially outward of the rotating shaft; and a winding force biasing means for constantly applying a rotational biasing force to the spool in the winding direction of the webbing. And one end of the brake member is rotatably supported by the housing and the other end is disposed in the webbing pull-out direction from the one end, and is provided with a brake member that is always in contact with the flange. A brake support plate supported and biased in the pressing direction of the webbing by the braking force biasing means, and one end rotatably supported by the other end of the brake plate support plate. A brake plate having a base portion formed with a low friction coefficient, a pad portion where at least the surface of the spool is formed with a high friction coefficient at the tip from the base portion, and one end supported by the brake plate support plate and the other And a separating force urging means that is supported by the braking plate and urges the braking plate in the webbing separating direction, and when the webbing is wound by a predetermined amount, the base or A part of the base side of the pad portion is in contact with the webbing.

According to a second aspect of the invention, in the seat belt retractor according to claim 1, wherein the pad portion is characterized in that the surface area of the spool side is increased toward the tip from the base.

  According to the first aspect of the present invention, as the winding force of the webbing wound on the spool increases, a large braking force can be applied to the webbing. Therefore, even if the winding force of the webbing increases. Prevent the webbing from being taken up abruptly and prevent the tongue attached to the end of the webbing from striking the trim and damaging the trim or colliding with the car occupant Can do.

  In addition, according to the first aspect of the present invention, since rapid webbing winding is prevented, the occurrence of end lock can be prevented.

Furthermore, according to the first aspect of the present invention, the contact area of the braking surface with respect to the webbing can be changed according to the winding amount of the webbing wound on the spool. That is, when the webbing is pulled out, as the webbing winding amount decreases, the contact area of the braking surface with the webbing of the pad portion decreases, so the braking force of the braking surface against the webbing decreases. Therefore, webbing can be pulled out smoothly.

  On the other hand, at the time of winding the webbing, as the webbing winding amount increases, the contact area of the braking surface with the webbing of the pad portion increases, so that the braking force of the braking surface against the webbing increases. It will be. Therefore, it is possible to prevent the webbing from being rapidly wound and to smoothly wind the webbing at a constant speed.

According to the invention of claim 2 , the webbing is prevented from being taken up rapidly by bringing the surface of the brake plate having a high friction coefficient into contact with the webbing as the winding force of the webbing increases. The webbing can be smoothly wound at a constant speed.

(First embodiment)
Next, a first embodiment will be described with reference to the drawings. However, the scope of the invention is not limited to the illustrated examples. FIG. 1 is a perspective view of a seat belt retractor used in a seat belt apparatus according to the present invention.

  The seatbelt retractor 1 is provided with a housing 4 having a U-shaped cross section formed by a bottom plate 2 and side walls 3, 3 provided to face both ends of the bottom plate 2.

  A spool 5 is accommodated in the housing 4. As shown in FIG. 2, the spool 5 is provided so as to penetrate the cylindrical webbing take-up portion 6, flanges 9 and 9 provided at both ends of the webbing take-up portion 6, and the axis of the webbing take-up portion 6. The rotating shaft 10 is configured so that the rotating shaft 10 of the spool 5 is rotatably supported by bearings provided on the side walls 3 and 3.

  .. Are formed on the outer peripheral edges of the flanges 9 of the spool 5 so as to protrude outward in the radial direction with a predetermined interval in the circumferential direction.

  The spool 5 used in the present embodiment is not limited to the above, and may be any so-called cam shape in which the distance between the end face of the flange and the center axis of the spool is not constant. Therefore, for example, a plurality of notches are formed in the flanges 13 and 13 at both ends of the webbing take-up unit 6 as in the spool 12 shown in FIG. 3, or the webbing take-up unit 6 is formed in the spool 14 as shown in FIG. It is good also as what uses the center which the flanges 15 and 15 of the both ends of the rotating shaft 10 and the webbing winding part 6 have shifted | deviated.

  A belt-shaped webbing 16 is attached to the webbing take-up portion 6 of the spool 5 so that the webbing 16 can be wound, and one end of the rotary shaft 10 always applies a rotational force in the winding direction of the webbing 16 to the spool 5. It is connected to, for example, a spiral spring 18 which is a winding force urging means to be applied.

  As shown in FIG. 1, a braking member 19 is attached to the side walls 3, 3 of the housing 4 so as to be parallel to the rotating shaft 10 of the spool 5. As shown in FIG. 5, the rotating shaft 20 is formed to protrude at both ends of the base end portion of the braking member 19. The rotating shaft 20 is supported by bearings (not shown) formed on the side walls 3 and 3, and the braking member 19 is swingably attached in a direction away from the webbing 16.

  As shown in FIG. 5, a braking surface 21 is provided at the tip of the braking member 19 so as to face the surface of the webbing 16. The braking surface 21 is formed by, for example, a rubber pad.

  As shown in FIG. 5, two pins 22 and 23 are formed on the side walls 3 and 3 of the housing 4 so as to protrude inward of the housing 4, and a torsion coil spring 24 is supported on the pins 22. . One end of the torsion coil spring 24 is locked to the pin 23, and the other end is locked to the braking member 19, so that the tip of the braking member 19 is urged toward the webbing 16. The braking member 19 is biased in the direction of the webbing 16 by the torsion coil spring 24.

  On the other hand, as shown in FIG. 6, the outer peripheral edges of the flanges 9, 9 are positioned between the front end portion and the base end portion of the braking member 19 and opposed to the spool 5 at positions facing the outer peripheral edge of the flange 9. A protrusion 25 protruding in the direction is provided.

  The protrusion 25 is always in contact with the outer peripheral edge of the flange 9 so as to adjust the distance between the webbing 16 and the braking surface 21. In other words, the rotation of the braking member 20 in the direction of the webbing 16 is restricted by the protrusion 25. Therefore, the braking surface 21 does not come into contact with the webbing 16 unless the webbing 16 is wound on the spool 5 by a predetermined amount or more.

  Further, the spool 5 rotates and the projection 25 comes into contact with the projection 11 provided on the outer peripheral edge of the flanges 9, 9, and the pressing force of the projection 11 of the flanges 9, 9 against the projection 25 is When exceeding the urging force, as shown in FIG. 6, the braking member 19 is flipped up in a direction away from the webbing 16 with the end portion pivotally supported on the side walls 3 and 3 as an axis. At this time, the braking surface 21 that presses the webbing 16 is flipped up to a position where it cannot contact the surface of the webbing 16 even when the webbing 16 is entirely wound on the spool 5.

  Further, when the protrusions 11, 11... Do not come into contact with the protrusions 25 by the rotation of the spool 5, the braking member 19 moves again in the direction of the webbing 16. In this case, the braking surface 21 also moves in the direction of the webbing 16, and when the webbing 16 is wound around the spool 5 by a predetermined amount, the braking surface 21 presses the webbing 16.

  When the braking surface 21 presses the webbing 16, the braking surface 21 generates a frictional force that acts in the pulling direction of the webbing 16 when the webbing 16 is wound, and the frictional force in the winding direction of the webbing 16 when the webbing 16 is pulled out. Give rise to Since the braking member 19 is arranged so that the braking surface 21 is in the pulling direction of the webbing 16, a frictional force is generated in the winding direction of the webbing 16 when the webbing 16 is pulled out. It becomes smaller than time.

  The pressing force against the braking surface 21 changes with the winding amount of the webbing 16. That is, when the winding amount of the webbing 16 decreases, the pressing force decreases and the frictional force in the winding direction of the webbing 16 also decreases. On the other hand, when the winding amount of the webbing 16 increases, the pressing force of the braking surface 21 against the webbing 16 increases, and when the webbing 16 is wound, a large frictional force is generated in the pulling direction of the webbing 16.

  The brake member 19 may be detachable so that it can be used for seat belt retractors having different webbing thicknesses and belt lengths.

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

  First, the case where the webbing 16 is wound will be described.

  When an automobile occupant releases the engagement of a tongue and a buckle (not shown) attached to the tip of the webbing 16, the spiral spring 18 in the seat belt retractor 1 applies a rotational biasing force to the spool 5. Thereby, the spool 5 starts winding of the webbing 16 simultaneously with starting rotation.

  When the amount of the webbing 16 wound on the spool 5 exceeds a predetermined amount, the braking surface 21 comes into contact with the surface of the webbing 16. As the thickness of the webbing 16 increases, the torsion coil spring 24 applies a strong pressing force to the braking surface 21 to the webbing 16 and friction in the pulling direction that the braking surface 21 applies to the webbing 16. Power increases.

  When the webbing 16 is wound, the spool 5 rotates and the projection 25 comes into contact with the projections 11 and 11 of the flanges 9 and 9, and the pressing force against the projection 25 of the projections 11 and 11 causes the torsion coil spring 24 to brake. When the urging force applied to the member 19 is exceeded, the braking member 19 is flipped up in a direction away from the webbing 16 with the end portion pivotally supported on the side walls 3 and 3 as an axis. At this time, the braking surface 21 pressing the webbing 16 is also separated from the surface of the webbing 16.

  Further, when the spool 5 further rotates and shifts to the end face where the protrusions 11, 11... Of the flanges 9, 9 are not provided, the pressing force against the protrusions 25 of the flanges 9, 9 disappears, and the torsion coil spring 24. Due to the urging force, the braking member 19 moves again in the direction of the webbing 16. At this time, the braking surface 21 also moves in the direction of the webbing 16, and the braking surface 21 presses the webbing 16.

  Thus, the webbing 16 is wound around the webbing winding part 6 of the spool 5 while the braking force is intermittently applied from the braking surface 21.

  Next, a case where the webbing 16 is pulled out from the seat belt retractor 1 in a state where the entire amount of the webbing 16 is wound around the spool 5 will be described.

  When an automobile occupant pulls the webbing 16 with a tongue (not shown) attached to the end of the webbing 16 to pull out the webbing 16 from the seat belt retractor 1 against the rotational biasing force of the spiral spring 18. The spool 5 starts to rotate in the pulling direction of the webbing 16, and the webbing 16 starts to be pulled out from the seat belt retractor 1.

  The braking force applied to the webbing 16 from the braking surface 21 decreases as the thickness of the webbing 16 decreases. Therefore, the frictional force acting in the winding direction of the webbing 16 also decreases accordingly, so that the resistance when pulling out the webbing 16 is reduced, and the webbing 16 is easily pulled out. Further, the braking member 19 is arranged so that the braking surface 21 is located in the direction of pulling out the webbing 16 from the webbing 20 from the rotary shaft 20, so that the frictional force when pulling out is smaller than the frictional force when winding. It is easy.

  Further, the protrusion 25 of the braking member 19 is flipped up to the protrusions 11, 11... Of the flanges 9, and at the same time, the braking surface 21 is separated from the webbing 16. Disappears. Then, after the spring 25 is pushed up by the protrusion 25, the braking member 19 is pressed against the surface of the webbing 16 by the torsion coil spring 24.

  Further, when the webbing 16 is pulled out, the spool 5 rotates and the projections 25 come into contact with the projections 11 and 11 of the flanges 9 and 9, and the pressing force of the projections 11 and 11 against the projections 25 causes the torsion coil spring 24. When the urging force applied to the braking member 19 is exceeded, the braking member 19 is flipped up in a direction away from the webbing 16 with the end portion pivotally supported on the side walls 3 and 3 as an axis. At this time, the braking surface 21 pressing the webbing 16 is also separated from the surface of the webbing 16.

  Further, when the spool 5 further rotates and shifts to the end face where the protrusions 11, 11... Of the flanges 9, 9 are not provided, the pressing force against the protrusions 25 of the flanges 9, 9 disappears, and the torsion coil spring 24. Due to the urging force, the braking member 19 moves again in the direction of the webbing 16. At this time, the braking surface 21 also moves in the direction of the webbing 16, and the braking surface 21 presses the webbing 16.

  Thus, the webbing 16 wound around the spool 5 is pulled out while the braking force of the braking surface 21 against the webbing 16 is intermittently lost. When the amount of the webbing 16 wound on the spool 5 becomes a predetermined amount or less, the braking surface 21 is separated from the surface of the webbing 16 and the webbing 16 is further easily pulled out.

  Then, after pulling out a predetermined amount of webbing 16 from the seat belt retractor 1, the passenger engages a tongue (not shown) attached to an end of the webbing 16 with a buckle (not shown).

  As described above, according to the invention according to the present embodiment, when the webbing 16 is wound, a greater braking force is applied to the webbing 16 as the winding speed of the webbing 16 wound on the spool 5 increases. Since the webbing 16 is prevented from being taken up suddenly even when the rotational biasing force in the winding direction of the webbing 16 is increased, the tongue attached to the end portion of the webbing 16 is trimmed with a rapid momentum. It is possible to prevent the trim from being damaged and colliding with the passenger of the car.

  Moreover, since the winding of the webbing 16 is prevented, the occurrence of end lock can be prevented.

  Further, as the winding amount of the webbing 16 wound on the spool 5 increases and the winding force of the webbing 16 increases, the urging force of the torsion coil spring 24 on the braking member 19 in the direction of the webbing 16 increases. Since the pressing force of the surface 21 against the webbing 16 and the frictional force acting in the pull-out direction are increased, a large braking force can be applied to the webbing 16.

  Further, since the braking member 19 is flipped up by the projecting portions 11, 11..., The braking surface 21 does not always contact the webbing 16 but intermittently contacts. For this reason, when the webbing 16 is pulled out, if the braking surface 21 is not in contact with the webbing 16, the webbing 16 can be pulled out smoothly.

  Moreover, it can prevent that the braking surface 21 wears in a short time by making the braking surface 21 contact the webbing 16 intermittently.

(Second embodiment)
Next, a second embodiment will be described with reference to the drawings. In the second embodiment, the description of the parts common to the first embodiment will be omitted, and different parts will be mainly described.

  A braking member 30 is attached to the side walls 3 and 3 of the housing 4 so as to be parallel to the rotating shaft 10 of the spool 5. As shown in FIG. 7, the braking member 30 includes a braking plate support plate 31 and a braking plate 32. Rotating shafts 33 are formed so as to protrude from both ends of the base end portion of the brake plate support plate 31. The rotating shaft 33 is supported by bearings (not shown) formed on the side walls 3 and 3, and the brake plate support plate 31 is attached so as to be swingable in a direction away from the direction approaching the webbing 16.

  One end of a torsion coil spring 24 applied to the pin 22 is engaged with the brake plate support plate 31 and is urged toward the webbing 16.

  Further, as shown in FIG. 8, thin plate-like mounting plates 34 and 34 are provided on both side surfaces of the other end of the brake support plate 31, respectively. A long flat plate-like braking plate 32 fitted with a rotating shaft 35 projecting from both end surfaces in the longitudinal direction is slidably swingable on bearing portions (not shown) formed on the opposing surfaces of the mounting plates 34, 34. It is fixed.

  As shown in FIGS. 7 and 8, the braking surface 36 on the side facing the webbing 16 of the braking plate 32 has a friction coefficient higher than that of the material constituting the braking plate 32 so as to cover from the free end side to the vicinity of the center portion. A pad portion 39 formed with a high friction coefficient with a high, for example, a thin rubber pad, and a low friction surface that is the surface of the brake plate 32 with a lower friction coefficient than the pad portion 39 formed with a high friction coefficient. It is comprised by the base 40 formed with a coefficient.

  One end of a spiral spring 41 attached to the brake plate support plate 31 is engaged with the back surface of the brake surface 36 of the brake plate 32. Therefore, the brake plate 32 is biased in the contraction direction of the spiral spring 41, and the brake surface 36 of the brake plate 32 is attached to the brake plate support plate 31 so as to have a predetermined inclination angle with respect to the webbing 16. Yes.

  The brake plate support plate 31 may be detachable so as to be compatible with retractor devices having different webbing thicknesses or webbing lengths.

  As shown in FIG. 7, the surface of the brake plate support plate 31 facing the spool 5 is provided with a protrusion 42 protruding in the direction of the outer peripheral edge of the flange 9, 9 at a position facing the outer peripheral edge of the flange 9. It has been.

  The protrusion 42 is always in contact with the outer peripheral edge of the flange 9 so as to adjust the distance between the webbing 16 and the braking surface 36. In other words, the rotation of the braking member 30 in the direction of the webbing 16 is restricted by the protrusion 42. For this reason, the braking surface 36 does not come into contact with the webbing 16 unless the webbing 16 is wound around the spool 5 by a predetermined amount or more.

  Further, the spool 5 rotates and the projection 42 comes into contact with the projection 11 provided on the outer peripheral edge of the flanges 9, 9, and the pressing force against the projection 42 of the projection 11 of the flanges 9, 9 is applied to the torsion coil spring 24. When exceeding the urging force, as shown in FIG. 9, the braking member 30 is flipped up in a direction away from the webbing 16 with the end portion pivotally supported by the side walls 3 and 3 as an axis. At this time, the braking surface 36 that presses the webbing 16 is flipped up to a position where it cannot contact the surface of the webbing 16 even if the webbing 16 is fully wound on the spool 5.

  The braking member 30 is biased in the direction of the webbing 16 by the torsion coil spring 24. The brake plate 32 is swingably fixed to the brake plate support plate 31 and has a predetermined inclination angle with respect to the webbing 16 by the spiral spring 41, so that it is wound around the spool 5. The area where the braking surface 36 of the braking plate 32 abuts the webbing 16 is changed according to the amount of the webbing 16.

  That is, when the webbing 16 is wound around the webbing take-up portion 6 and becomes thick enough to come into contact with the brake plate 32, the base 40 of the brake plate 32 is first applied to the webbing 16 as shown in FIG. It comes to contact. Furthermore, when the amount of the webbing 16 to be wound up increases, the webbing 16 is applied to the braking plate 32 due to an increase in the thickness of the webbing 16 wound around the webbing winding unit 6. An applied pressing force is generated. Further, when the webbing 16 is wound around the spool 5, a frictional force acting in the pulling direction of the webbing 16 is generated between the base 40 and the webbing 16.

  The pressing force against the brake plate 32 increases as the winding amount of the webbing 16 increases, and the frictional force increases as the winding speed of the webbing 16 increases. As a result, when the resultant force of the pressing force and the frictional force becomes larger than the urging force of the spiral spring 41, the spiral spring 41 starts to expand. As a result, the braking plate 32 having one end attached to the spiral spring 41 also gradually starts approaching the webbing 16 with its free end centered on the oscillation center as the spiral spring 41 extends. At the same time, the contact area between the braking surface 36 and the webbing 16 gradually increases.

  That is, as shown in FIG. 10, the contact area between the base 40 and the webbing 16 first increases as the resultant force of the pressing force and the frictional force becomes larger than the biasing force of the spiral spring 41. Further, contact with the pad portion 39 is started to increase the contact area between the pad portion 39 and the webbing 16 so that the braking force applied to the webbing 16 by the brake plate 32 is increased.

  When the entire amount of the webbing 16 is wound on the spool 5, the resultant force of the pressing force and the frictional force is the largest than the urging force of the spiral spring 41, and the contact area between the braking surface 36 and the webbing 16 is also the largest. .

  In contrast, when the webbing 16 that has been wound up in its entirety is pulled out of the seat belt retractor 1, a frictional force acts between the webbing 16 and the braking surface 36 in the winding direction side of the webbing 16. It has become. When the webbing 16 is pulled out of the seatbelt retractor 1 and the winding amount of the webbing 16 is reduced, the pressing force applied to the brake plate 32 of the webbing 16 is reduced and the frictional force is also reduced.

  When the urging force of the spiral spring 41 becomes larger than the resultant force of the pressing force and the frictional force, the spiral spring 41 starts to contract in the contraction direction. Therefore, the braking plate 32 having one end attached to the spiral spring 41 also starts to separate from the webbing 16 with the rotary shaft 33 as an axis in accordance with the contraction of the spiral spring 41. At the same time, the contact area between the braking surface 36 and the webbing 16 is also gradually reduced.

  That is, as the urging force of the spiral spring 41 becomes larger than the resultant force of the pressing force and the frictional force, the contact area between the pad portion 39 and the webbing 16 first decreases. When the contact area with the pad portion 39 disappears, the contact area with the base portion 40 further decreases.

  When the thickness of the webbing 16 wound around the spool 5 becomes a thickness that does not contact the base portion 40 of the braking surface 36, the braking surface 36 does not contact the webbing 16, and the braking surface 36 is applied to the webbing 16. The braking force disappears.

  Further, when the protrusion 42 of the brake plate support plate 31 comes into contact with the outer peripheral edge of the flanges 9 and 9 and the brake plate support plate 31 is flipped up, the webbing 16 is entirely wound up on the brake plate 32 as well. Are also able to jump up to a position where they cannot contact the webbing 16 at the same time.

  When the protrusions 11, 11... Do not come into contact with the protrusions 42 due to the rotation of the spool 5, the brake plate support plate 31 moves in the direction of the webbing 16 and the brake plate 32 also moves in the direction of the webbing 16. When the webbing 16 is wound around the spool 5 by a predetermined amount, the braking surface 36 presses the webbing 16.

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

  First, the case where the webbing 16 is wound will be described. When an automobile occupant releases the engagement of a tongue and a buckle (not shown) attached to the tip of the webbing 16, the spiral spring 18 in the seat belt retractor 1 applies a rotational biasing force to the spool 5, and the spool 5 rotates. The webbing 16 starts to be wound at the same time.

  At the beginning of winding, the base portion 40 of the braking surface 36 is mainly in contact with the webbing 16. However, as the thickness of the webbing 16 wound around the spool 5 increases, the contact area of the pad portion 39 increases. To increase. Then, the pad portion 39 increases the contact area with the webbing 16 according to the winding amount of the webbing 16 and applies a large braking force by the rotational biasing force of the spiral spring 18.

  At this time, the protrusion 42 of the brake plate support plate 31 is flipped up to the protrusions 11, 11... Of the flanges 9, and at the same time, the brake plate 32 is separated from the webbing 16. The applied braking force disappears. As described above, the webbing 16 is wound around the webbing winding unit 6 of the spool 5 while the braking force is intermittently applied from the braking plate 32.

  Next, a case where the webbing 16 is pulled out from the seat belt retractor 1 in a state where the entire amount of the webbing 16 is wound around the spool 5 will be described.

  When an automobile occupant pulls the webbing 16 with a tongue (not shown) attached to the end of the webbing 16 to pull out the webbing 16 from the seat belt retractor 1 against the rotational biasing force of the spiral spring 18. The spool 5 starts to rotate in the pulling direction of the webbing 16, and the webbing 16 starts to be pulled out from the seat belt retractor 1.

  At the beginning of the pulling out, almost the entire braking surface 36 of the braking plate 32 is in contact with the webbing 16, so that a large braking force is generated on the webbing 16. However, as the webbing 16 is pulled out, the thickness of the webbing 16 wound around the spool 5 is reduced, and the contact area between the pad portion 39 and the webbing 16 is reduced at the same time, so that the braking force acting on the webbing 16 is reduced. Becomes smaller and the resistance when the webbing 16 is pulled out becomes smaller.

  Further, when the thickness of the webbing 16 is reduced, the contact area between the pad portion 39 and the surface of the webbing 16 disappears while decreasing. Next, the contact area with the base 40 starts to decrease. Therefore, the resistance when pulling out the webbing 16 further decreases.

  Also, when the webbing 16 is pulled out from the seat belt retractor 1, the protrusion 42 of the brake plate support plate 31 is sprung up to the protrusions 11, 11... Of the flanges 9, and the brake plate 32 is moved from the webbing 16. Since it is repeated intermittently that the braking force applied to the webbing 16 of the brake plate 32 after being spaced apart disappears, it becomes easier for the passenger to pull out the webbing 16.

  When the amount of the webbing 16 wound on the spool 5 becomes a predetermined amount or less, the braking surface 21 is separated from the surface of the webbing 16 and the webbing 16 is further easily pulled out.

  In this way, after pulling out a predetermined amount of the webbing 16 from the seatbelt retractor 1, the passenger engages a tongue (not shown) attached to the end of the webbing 16 with a buckle (not shown).

  As described above, according to the invention according to the present embodiment, the contact area of the braking surface with respect to the webbing can be changed according to the winding amount of the webbing 16 wound around the spool 5. That is, when the webbing 16 is pulled out, the contact area of the pad portion 39 with the webbing 16 on the braking surface 36 decreases as the winding amount of the webbing 16 decreases. Decrease. Therefore, the webbing 16 can be pulled out smoothly.

  On the other hand, when the webbing 16 is wound, the contact area of the pad portion 39 with the webbing 16 on the braking surface 36 increases as the winding amount of the webbing 16 increases. The braking force for 16 will increase. For this reason, it is possible to prevent the webbing 16 from being rapidly wound and to smoothly wind the webbing 16 at a constant speed.

  Further, as the winding speed of the webbing 16 wound around the spool 5 increases, a large braking force can be applied to the webbing 16 by the pad portion 39, so that the rotational urging force of the webbing 16 in the winding direction increases. However, the webbing 16 is prevented from being taken up suddenly, and the tongue attached to the end of the webbing 16 collides with the trim at a rapid momentum and damages the trim or collides with the passenger of the car. Can be prevented.

  Further, as the winding amount of the webbing 16 wound around the spool 5 increases and the winding force of the webbing 16 increases, the contact area of the braking plate 32 with the webbing 16 increases, and a large braking force is applied to the webbing 16. You can hang it.

  Further, by intermittently bringing the brake plate 32 into contact with the webbing 16, it is possible to prevent the braking surface 36 of the brake plate 32, particularly the pad portion 39, from being worn in a short time.

It is a perspective view of the retractor concerning the present invention. It is a perspective view of the spool which concerns on this invention. It is a perspective view of the modification of the spool which concerns on this invention. It is a perspective view of the modification of the spool which concerns on this invention. It is a side view of the braking member concerning the present invention. It is a side view showing the state where the braking member concerning a first embodiment was flipped up to the projection part of the spool. It is a side view which shows the state which the base formed with the low friction coefficient of the braking plate of a braking member is contact | abutting to webbing. It is a perspective view showing the state which attached the brake plate to the brake plate support plate. It is a side view which shows the state by which the braking member which concerns on 2nd embodiment was flipped up by the protrusion part of the spool. It is a side view which shows the state which the end of the pad part formed with the high friction coefficient of the braking plate of a braking member is contact | abutting to webbing.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Retractor for seat belts 4 Housing 5 Spool 6 Webbing take-up part 9 Flange 10 Rotating shaft 11 Protruding part 12 Spool 13 Flange 14 Spool 15 Flange 16 Webbing 18 Spiral spring 19 Brake member 20 Rotating shaft 21 Brake surface 22 Pin 23 Pin 24 Twist Coil spring 25 Protruding portion 30 Brake member 31 Brake plate support plate 32 Brake plate 33 Rotating shaft 34 Mounting plate 35 Rotating shaft 36 Braking surface 39 Pad portion formed with high friction coefficient 40 Base portion formed with low friction coefficient 41 Spiral spring 42 protrusion

Claims (2)

A spool that is rotatably supported on the housing by a rotating shaft, and includes a webbing winding portion that winds up the webbing and flanges that are provided at both ends of the webbing winding portion and extend radially outward of the rotating shaft;
A winding force biasing means for constantly applying a rotational biasing force in the winding direction of the webbing to the spool;
A seat belt retractor comprising:
One end is rotatably supported by the housing and the other end is disposed in the webbing pull-out direction from the one end, and includes a braking member that is always in contact with the flange.
The braking member is
A braking support plate having one end rotatably supported by the housing and biased in the pressing direction of the webbing by the braking force biasing means;
Braking having one end rotatably supported on the other end of the brake plate support plate and having a base portion formed with a low friction coefficient and a pad portion formed with at least the surface of the spool at the tip from the base portion with a high friction coefficient. The board,
One end is supported by the brake plate support plate, the other end is supported by the brake plate, and a separation force urging means that urges the brake plate in the webbing separation direction,
A retractor for a seat belt, wherein a part of a base side of the base part or the pad part comes into contact with the webbing when the webbing is wound up by a predetermined amount . The seatbelt retractor according to claim 1 , wherein the pad portion has a surface area on the spool side that increases from the base portion toward the tip portion.

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