JP4627229B2 - Seat belt retractor - Google Patents

Description

  The present invention relates to a seat belt retractor provided with an emergency lock activation device that reacts to a rapid change in acceleration of a vehicle.

  Generally, a seat belt device provided in a seat of a vehicle or the like is configured such that webbing is wound around a retractor provided with a lock mechanism. In a collision or the like, the emergency lock activation device is activated by detecting a sudden change in acceleration due to the impact force to activate the lock mechanism and prevent the winding drum around which the webbing is wound from rotating. This prevents the webbing from being pulled out and restrains and protects the passenger (see, for example, Patent Document 1 or Patent Document 2).

  That is, an emergency lock activation device includes a box-shaped holder having a concave portion on a bottom surface, a spherical inertia mass body that is disposed in the concave portion of the holder and swings in response to an acceleration change exceeding a predetermined value, and a holder And a sensor lever that rotates around the axis of the shaft portion according to the swing of the inertia mass body and activates the lock mechanism. It was.

  The casing provided on one side of the seat belt retractor houses the lock mechanism and the emergency lock activation device. The sensor lever of the emergency lock activation device is attached to the ratchet tooth of the ratchet wheel of the lock mechanism. By meshing, the winding drum around which the webbing is wound is prevented from rotating, and the webbing is prevented from being pulled out to restrain and protect the passenger.

  On the other hand, the inertial mass body swings not only in an emergency such as a vehicle collision, but also due to vibrations during normal traveling, etc., so that the sensor lever is rotated around the shaft center of the shaft portion by such swinging. The noise collided with the inner surface of the casing, etc., and generated abnormal noise, which was annoying noise.

  Therefore, as an emergency lock activation device designed to reduce such noise, a sensor housing having a concave body for receiving the sensor ball, and a sensor lever pivotally attached to the sensor housing and having a cap on the sensor ball. Each of the cap and the concave body is coupled to the sensor housing via at least one elongated web, and the web is elastically deformable by vibration during normal use to generate noise. (For example, refer to Patent Document 3).

Japanese Patent Laid-Open No. 2003-212085 JP 2003-212086 A JP-A-5-193442

  However, according to the noise reduction structure disclosed in Patent Document 3, when operating in an emergency such as an actual collision, the sensor ball not only moves, but also the elongated web elastically deforms due to the vibration of the vehicle. There is a possibility that the operation of the lock mechanism itself in the retractor may be delayed due to the sensing being delayed due to the shift of the lock position of the sensor lever.

  Further, when the elastic deformation of the web due to the vibration of the vehicle over a long period of time due to the long-term use of the vehicle, the mutual positional relationship of the members constituting the emergency lock starting device is displaced, and the sensor lever There is also a possibility that the lock position of the actuator is displaced and the activation of the lock mechanism becomes unstable.

  Accordingly, an object of the present invention is to provide a seatbelt retractor that ensures stable activation of the lock mechanism and reduces noise.

  The technical means for solving the above-mentioned problems are a housing formed in a substantially U-shaped cross-section in which a through hole is provided in each of a pair of opposing side plates, and a housing inserted through the through-holes in the pair of side plates. A winding drum that is rotatably supported by the webbing and wound in the direction in which the webbing is wound, and a lock mechanism that suppresses rotation of the winding drum in the webbing pull-out direction in the event of a vehicle emergency, An emergency lock activation device that activates the lock mechanism in response to a sudden acceleration change of the vehicle, the lock mechanism including a lock tooth formed on one inner peripheral surface of the through hole of the housing, and the lock tooth Next to the lock base part provided on the take-up drum on the inside, the pawl that protrudes from the outer peripheral surface of the lock base part so as to protrude and engage with the lock teeth, and the outer surface side of the lock base part It is attached so as to be rotatable relative to the winding drum and is attached so as to be able to rotate synchronously with the lock base portion while being urged in the webbing pull-out direction. The emergency lock activation device is provided with a box-shaped holder having a concave portion on the bottom surface, and is disposed in the concave portion of the holder and reacts to an acceleration change exceeding a predetermined value. An inertia mass body that swings in rotation and a shaft portion that is rotatably supported by the holder, and is rotated by the swing of the inertia mass body and rotates around the axis of the shaft portion to thereby rotate the outer periphery of the lock clutch body. Sensor lever that meshes with the surface, and is attached to one side of the housing where the lock mechanism is installed, and stores the emergency lock activation device In a seat belt retractor having a casing that restricts rotation of the sensor lever, the lock clutch body is allowed to rotate when the sensor lever is not rotated, and is engaged with the outer peripheral surface of the lock clutch body when the sensor lever is rotated. In this range, at least one of the casing and the sensor lever is provided with an abutment rib that abuts on and away from the other.

  Further, the lock clutch body has a ratchet wheel having ratchet teeth formed on an outer peripheral surface, and when the sensor lever and the casing are in contact via the contact rib, the sensor lever is a ratchet of the ratchet wheel. It is good also as a structure which has set the height of the said contact rib so that it may mesh | engage with the substantially intermediate | middle site | part of a tooth tip and a tooth base.

  Furthermore, the abutment rib may be structured to be elastically deformable.

  The contact rib may be provided on the sensor lever.

  According to the seat belt retractor of the present invention, the rotation of the lock clutch body is permitted when the sensor lever is not rotated, and the casing or the sensor lever is engaged within a range where the lock is engaged with the outer peripheral surface of the lock clutch body when the sensor lever is rotated. Since at least one of the two is provided with an abutment rib that comes into contact with and away from the other, the abutment rib reduces the gap between the sensor lever and the casing, resulting in vibration during normal travel. Owing to the swinging of the sensor lever due to the above, it is possible to suppress the generation of abnormal noise even if it collides with the casing, and noise can be reduced.

  Moreover, there is no elongate web which elastically deforms by vibration as in Patent Document 3, and there is an advantage that a stable lock mechanism can be started.

  Furthermore, the lock clutch body has a ratchet wheel having ratchet teeth formed on the outer peripheral surface. If the structure is such that the height of the abutment rib is set so that it meshes with a substantially intermediate portion with the original, the abutment rib is on the other side until the tooth tips of the sensor lever and the ratchet wheel abut against each other. Since the interference does not occur, the lock function can be reliably activated.

  In addition, if the contact rib has a structure that can be elastically deformed, after the tooth tips of the sensor lever and the ratchet wheel come into contact with each other, the contact rib is elastically deformed, so that the tooth tip of the sensor lever becomes the ratchet wheel. By moving to the tooth base, it is possible to engage with each other more reliably, and the lock mechanism can be activated more stably.

  Furthermore, if the contact rib is provided on the sensor lever, there is an advantage that it can be easily manufactured.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIGS. 1 to 6 show a resin provided on one side surface of a housing 2 which is a main part of the present embodiment of a seat belt retractor 1. The casing 3 which consists of a molded object, and the emergency lock starting device 4 accommodated in the holder accommodating part 3a provided in the casing 3 are shown, and the whole structure of the retractor 1 itself is the conventional patent document 1 or patent document 2 Therefore, the detailed description thereof will be omitted.

  That is, as shown in FIG. 7, the housing 2 is formed in a substantially U-shaped cross section in which a through hole 2 b is provided in each of a pair of opposing side plates 2 a, and the winding drum 14 is formed in the pair of side plates 2 a. It is inserted into the through hole 2b of the side plate 2a and is rotatably supported by the housing 2. The webbing is wound around the winding drum 14 and the winding drum 14 is constantly urged to rotate in the direction of winding the webbing by the winding mechanism 15.

  The winding mechanism 15 includes a connecting shaft 16 connected to the shaft portion of the winding drum 14, a winding attachment urging mechanism 17 including a spiral spring or the like that is locked to one end of the connecting shaft 16, and the winding attachment. And a spring case 18 that houses the biasing mechanism 17 and is disposed and fixed on the outer surface side of the side plate 2a.

  A lock mechanism housing portion 3b that is provided in continuation with the holder housing portion 3a of the casing 3 houses a lock mechanism 5 that suppresses the rotation of the winding drum 14 in the webbing pull-out direction and stops the webbing pull-out. .

  The lock mechanism 5 includes a lock tooth 2c formed in a sawtooth shape along the circumferential direction on the inner peripheral surface of one through-hole 2b of the housing 2, and the winding drum inside the lock tooth 2c, as in the prior art. 14, a lock base portion 20 that is integrally provided on one side, a pawl 21 that protrudes freely from the outer peripheral surface of the lock base portion 20 and meshes with the lock teeth 2 c, and an outer surface of the lock base portion 20. Is attached so as to be relatively rotatable with respect to the winding drum 14 adjacent to the side, and is attached so as to be able to rotate synchronously with the lock base portion 20 while being biased in the webbing pull-out direction by the return spring 22. And a lock clutch body 6 for projecting the pawl 21 by relative rotation. Therefore, the lock clutch body 6 is connected to the take-up drum 14 so as to rotate together. Further, the lock clutch body 6 is formed with a guide groove 6a in which an interlocking pin 21a protruding from the pawl 21 is fitted and guided to slide, and the lock base portion 20 and the lock clutch body 6 The interlocking pin 21a is slidably guided along the guide groove 6a due to the relative rotation, and the pawl 21 protrudes from the outer peripheral surface of the lock base portion 20 by this sliding guide so as to be engaged with the lock teeth 2c of the side plate 2a. It is said that.

  A cylindrical ratchet wheel 7 having ratchet teeth 7 a formed on the outer peripheral surface is integrally provided on the outer peripheral portion of the lock clutch body 6. Then, the rotation of the ratchet wheel 7 is prevented, so that the lock clutch body 6 is prevented from rotating, and further, the winding drum 14 is prevented from rotating in the webbing pull-out direction, and the webbing pull-out is stopped. ing.

  A lock arm 8 is swingably supported by the lock clutch body 6, and the lock claw portion 8 a of the lock arm 8 is moved by the lock arm 8 by the swing of the lock arm 8. The lock clutch body 6 is also prevented from rotating by being detachably locked to a locking tooth portion 3d of a locking cylinder portion 3c projecting in a cylindrical shape on the inner surface side. . In FIG. 7, reference numeral 23 denotes a sensor spring that regulates inadvertent swinging of the lock arm 8, 24 denotes a lock pin on which the webbing is locked, 25 denotes a protector, and 26 denotes a cap.

  The emergency lock activation device 4 is arranged in a mounting manner on a holder 10 formed of a box-shaped resin molded body having a concave portion 10a having a concave shape on the bottom surface with an open top surface, and a concave shape on the bottom surface. And a spherical sensor weight 11 made of a steel material as an inertial mass body that swings in response to an acceleration exceeding a predetermined value, and a resin molded body having an appropriate elasticity that is rotatably supported by the holder 10. And a sensor lever 12.

  The sensor lever 12 is provided with a shaft portion 12a that protrudes on both sides at one end portion in the upper portion thereof. And each said shaft part 12a of the sensor lever 12 is each fitted by each support hole 10c of the support wall part 10b formed in the upper side protruding shape in the both sides in one edge part of the holder 10, respectively, The sensor lever 12 is configured to be supported by the holder 10 so as to be rotatable around the shaft portion 12a.

  Further, a rotation restricting piece 12b is extended downward toward the edge of the shaft portion 12a of the sensor lever 12, and the side wall surface 10d of the holder 10 is rotated by the rotation of the sensor lever 12 around the shaft portion 12a. , The rotation range of the sensor lever 12 is restricted, and the sensor weight 11 is not separated from the gap between the holder 10 and the sensor lever 12.

  Further, the other end portion of the sensor lever 12 includes an arm portion 12c extending downward for a predetermined length, and a lower end portion of the arm portion 12c meshes with the ratchet teeth 7a of the ratchet wheel 7 so as to be freely engaged and disengaged. The locking claw 12d is a meshing tooth.

  The sensor lever 12 has a so-called bowl-shaped upper cover portion 12e so as to cover the upper portion of the sensor weight 11 disposed in the concave portion 10a.

  The sensor weight 11 arranged in a mounting manner on the concave portion 10a and the peripheral wall portion 10e of the holder 10 surrounding the periphery thereof have an appropriate gap over the entire circumference in the circumferential direction. The sensor weight 11 is configured to be movable from the concave portion 10a and swingable within the gap. The upper cover portion 12e is pushed up by the sensor weight 11 due to the swing of the sensor weight 11, and the sensor lever 12 is configured to push the arm portion 12c side up around the shaft portion 12a.

  Further, mounting grooves 3e facing each other are formed in the holder accommodating portion 3a of the casing 3, and the slide leg portion 10f provided on the lower surface of the holder 10 is slidably fitted to the mounting groove 3e from the side. Thus, the emergency lock activation device 4 is accommodated and held in the holder accommodating portion 3a. Further, a stopper portion 10g is provided at the upper end portion of the support wall portion 10b of the holder 10 so as to abut against the peripheral edge portion of the holder accommodating portion 3a so as to regulate the fitting position of the emergency lock activation device 4, and the holder accommodating portion. The portion 3a is provided with a lid portion 3f that covers the side surface of the emergency lock activation device 4 in a fitted state of the emergency lock activation device 4 so as to be opened and closed.

  Then, after the emergency lock activation device 4 is fitted in the holder accommodating portion 3a, the lid portion 3f is closed, and the structure is attached to one side surface of the housing 2. When an acceleration exceeding a predetermined value is applied in this mounted state, the sensor weight 11 moves from the concave portion 10a and pushes the sensor lever 12 upward as shown by the phantom line in FIG. As shown in the figure, the lock claw 12d of the sensor lever 12 pushed by the movement of the sensor weight 11 is configured to engage with the ratchet teeth 7a of the ratchet wheel 7 in a releasable manner.

  In addition, a step portion 12f that protrudes toward the lock mechanism housing portion 3b is formed at an intermediate portion in the length direction of the arm portion 12c in the sensor lever 12, and the casing 3 includes the step portion 12f and the arm portion 12c. Rotating stopper portions 3g and 3h are provided in an overhang shape so as to come into contact with and separate from the upper surface portion and appropriately regulate the rotation range of the sensor lever 12 in the meshing direction with the ratchet wheel 7.

  Particularly in this embodiment, a single contact rib 12g is integrally formed on the upper surface of the step portion 12f along the protruding direction of the step portion 12f. Therefore, as shown in FIG. 3 and FIG. 4, the rotation of the sensor lever 12 causes the abutment rib 12 g to abut on and away from the rotation stopper portion 3 g, so that the sensor lever 12 engages with the ratchet wheel 7. The structure is such that the rotation is restricted.

  In the state where the contact rib 12g is in contact with the rotation stopper portion 3g, the lock claw 12d of the sensor lever 12 is connected to the tip and root of the ratchet tooth 7a of the ratchet wheel 7, as shown in FIG. It is comprised so that it may be rotated to the substantially intermediate part position.

  When an abrupt acceleration change occurs in an emergency such as a vehicle collision or sudden braking, the sensor weight 11 swings and moves from the concave portion 10a in response to the acceleration change. As the sensor weight 11 moves, the sensor lever 12 is pushed upward by the sensor weight 11, and the sensor lever 12 rotates about the shaft portion 12a.

  When the lock claw 12d is engaged with the ratchet teeth 7a of the ratchet wheel 7 by the rotation of the sensor lever 12, the rotation of the lock clutch body 6 is stopped. Therefore, if a load in the pulling direction acts on the webbing, the return spring The lock base 20 rotates relative to the pulling direction of the webbing against the urging force of 22.

  As the lock base portion 20 rotates, the interlocking pin 21a of the pawl 21 held by the lock base portion 20 slides in the guide groove 6a. Along with this sliding movement, the pawl 21 is projected and moved radially outward from the lock base portion 20 and meshes with the lock teeth 2c formed on the side plate 2a of the housing 2, and then the lock base portion 20, that is, the winding. The take-up drum 14 is prevented from rotating, the webbing is stopped, and the lock mechanism 5 is activated.

  When the sudden acceleration change is released, the sensor weight 11 is returned to the center on the concave portion 10a that is the original rest position of the holder 10 by the gravity action, and the sensor lever 12 is also rotated accordingly. Return to the initial position and return to the initial state where the webbing can be pulled out and wound.

  On the other hand, since the load in the pulling direction acting on the webbing is also released, the lock clutch body 6 is rotated relative to the lock base portion 20 by the urging force of the return spring 22 and the like, and this rotation causes the interlock in the guide groove 6a. The pin 21a is returned to the initial position, where the pawl 21 is returned to the buried state, and the engagement between the pawl 21 and the lock teeth 2c is released. Then, the webbing is returned to the initial state where the webbing can be pulled out and taken up.

  The present embodiment is configured as described above, and not only the rotation range of the sensor lever 12 around the shaft portion 12a is restricted by the rotation stopper portion 3g of the casing 3, but also the arm portion 12c of the sensor lever 12. Since the contact rib 12g is further provided in the step portion 12f provided in the contact portion 12f, the contact rib 12g reduces the gap between the sensor lever 12 and the casing 3 and the contact area between them, so that during normal driving Oscillation of the sensor lever 12 due to vibration or the like in this case can effectively suppress the generation of abnormal noise even when the sensor lever 12 collides with the casing, thereby reducing noise.

  In addition, the contact rib 12g does not interfere with the rotation stopper portion 3g until the lock claw 12d of the sensor lever 12 and the ratchet teeth 7a of the ratchet wheel 7 come into contact with each other, so that the lock mechanism 5 is activated. There is also an advantage that can be surely secured.

  Furthermore, in the present embodiment, the sensor lever 12 is made of an elastically deformable resin molded body, so that the tip of the lock claw 12d of the sensor lever 12 and the tip of the ratchet tooth 7a of the ratchet wheel 7 are in contact with each other. Later, when the contact rib 12g is elastically deformed, the tooth of the lock claw 12d in the sensor lever 12 moves to the base of the ratchet tooth 7a in the ratchet wheel 7, and the meshing becomes more reliable. 5 can be obtained more stably.

  In addition, since the abutment rib 12g can be elastically deformed, the collision between the rotation stopper portion 3g and the abutment rib 12g can be buffered, and also from this point, the generation of abnormal noise can be suppressed and noise can be reduced. There are advantages.

  Further, since the contact rib 12g is provided on the sensor lever 12 side, there is an advantage that it can be easily manufactured as compared with the case where the contact rib is provided on the rotation stopper portion 3g side of the casing 3.

  Further, the sensor lever 12 has a simple structure in which the abutment rib 12g is provided in a protruding shape. From this point, there is an advantage that it can be easily manufactured.

  FIG. 8 shows a second embodiment, and the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In other words, in the present embodiment, a single abutment rib 12h that abuts on and away from the rotation stopper portion 3h of the opposing casing 3 on the upper surface portion of the arm portion 12c is the front-rear direction with respect to the paper surface of FIG. It is set as the structure integrally formed along. Other structures are the same as those in the first embodiment.

  Therefore, the present embodiment also has the same effect as the first embodiment.

  In the above-described embodiments, the structure in which the contact ribs 12g and 12h are provided on the sensor lever 12 side is shown. However, the contact ribs are provided on the rotation stopper portions 3g and 3h side of the casing 3 facing each other. A structure may be used, and further, a contact rib may be provided on both the sensor lever 12 and the casing 3. Further, the number of the contact ribs 12g and 12h provided is not limited to a single one.

  Furthermore, the structure in which the lock base portion 20 is integrally provided on one side portion of the winding drum 14 is shown. However, as disclosed in Patent Document 1, the lock base portion 20 is separated from the winding drum 14. The structure may be a structure that is connected to be able to rotate together.

It is a principal part disassembled perspective view of the retractor in the 1st Embodiment of this invention. It is a disassembled perspective view of the emergency lock starting device. It is a partial cross section side view of a retractor. It is the principal part enlarged view. It is a side view of an emergency lock starting device. It is the VI-VI line arrow directional view of FIG. It is a disassembled perspective view of a retractor. It is a principal part enlarged view which shows 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Seat belt retractor 2 Housing 3 Casing 3a Holder accommodating part 3b Lock mechanism accommodating part 4 Emergency lock starting device 5 Lock mechanism 6 Lock clutch body 7 Ratchet wheel 7a Ratchet tooth 10 Holder 10a Concave part 11 Sensor weight 12 Sensor lever 12d Lock Claw 12g Contact rib 12h Contact rib 14 Winding drum 20 Lock base 21 Paul

Claims (4)

A housing having a substantially U-shaped cross-section in which a pair of opposing side plates are provided with through holes, and a pair of side plates that are inserted through the through holes of the pair of side plates so as to be rotatably supported by the webbing. In addition, a winding drum that is urged to rotate in the direction of winding the webbing, a lock mechanism that suppresses rotation of the winding drum in the webbing pull-out direction in the event of a vehicle emergency, and a lock mechanism that responds to sudden changes in the acceleration of the vehicle An emergency lock activation device that activates
The lock mechanism includes a lock tooth formed on the inner peripheral surface of one through hole of the housing, a lock base portion provided on the take-up drum inside the lock tooth, and can be protruded and retracted from an outer peripheral surface of the lock base portion. And a lock base portion that is attached to the outer side of the lock base portion so as to be relatively rotatable with respect to the take-up drum and is biased in the webbing pull-out direction. A lock clutch body mounted so as to be able to rotate synchronously and projecting a pawl by relative rotation with the lock base portion by the operation of the emergency lock activation device;
The emergency lock activation device includes a box-shaped holder having a concave portion on a bottom surface, an inertia mass body disposed in the concave portion of the holder and swinging in response to an acceleration change exceeding a predetermined value, and rotating to the holder. A sensor lever that has a shaft portion that can be supported and is rotated by the swing of the inertia mass body and rotates about the shaft center of the shaft portion to mesh with the outer peripheral surface of the lock clutch body;
In a retractor for a seat belt provided with a casing that is attached to one side of a housing in which a lock mechanism is disposed and that houses an emergency lock activation device and restricts rotation of a sensor lever.
As long as the lock clutch body is allowed to rotate when the sensor lever is not rotating, and is engaged with the outer peripheral surface of the lock clutch body when the sensor lever is rotated, the casing or at least one of the sensor lever and the other A retractor for a seat belt, characterized in that an abutment rib that abuts on and off is provided. The retractor for a seat belt according to claim 1,
The lock clutch body has a ratchet wheel having ratchet teeth formed on the outer peripheral surface,
When the sensor lever and the casing are in contact with each other via the contact rib, the sensor lever is engaged with a substantially intermediate portion between the tip and the base of the ratchet tooth of the ratchet wheel. The seatbelt retractor is characterized in that the height is set. In the seatbelt retractor according to claim 1 or 2,
The retractor for a seat belt, wherein the contact rib is elastically deformable. In the seatbelt retractor according to any one of claims 1 to 3,
A retractor for a seat belt, wherein the contact rib is provided on the sensor lever.

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