JP2010149585A - Seat belt retractor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seat belt retractor properly starting a lock operation of seat belt drawing operation even during transition from moderate deceleration to rapid deceleration. <P>SOLUTION: An acceleration sensor 100 includes a sensor holder 10 tilted integrally with a seat back S; a sensor case 20 supported by the sensor holder 10 so as to freely oscillate and normally horizontally holding an inertial field supporting surface 23 by oscillating during the tilting of the seat back; a self-sustaining inertial field 30 housed in the sensor case 20 while being mounted to the inertial field supporting surface 23, and displaced from its neutral position upon the application of a horizontal acceleration not smaller than a predetermined value; first and second sensor levers 50 and 40 for actuating a lock mechanism by motion generated during the displacement of the inertial field 30; a second inertial field 60 supported so as to freely oscillate and moving according to horizontal acceleration smaller than acceleration to cause the oscillation of the sensor case 20; and a lock tooth 5b and lock claws 74, 75 for locking the sensor case 20 when the second inertial field 60 is moved relatively to the sensor case 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a seat belt retractor built in a seat back of a reclining vehicle seat.

  A seat belt device mounted on a vehicle is for restraining an occupant of a vehicle seat by a seat belt pulled out from a seat belt retractor in a seat back to protect the occupant at the time of a vehicle collision or the like. When an acceleration greater than a predetermined value is applied in the horizontal direction in the event of a vehicle collision, the seat belt retractor detects this acceleration and activates the seat belt locking mechanism, thereby making it impossible to pull out the seat belt. . As an inertial body used for an acceleration sensor, one using a ball or one using a self-supporting inertial body is known.

  If a seatbelt retractor equipped with this type of acceleration sensor is installed on the reclining-type vehicle seatback, the seatbelt retractor mounting orientation will change depending on the reclining angle of the seatback. The acceleration cannot be detected. Therefore, for example, Patent Literature 1 and Patent Literature 2 provide a seat belt retractor equipped with an acceleration sensor that can appropriately detect acceleration regardless of the reclining angle of the seat bag.

  FIG. 8 is a view showing an example of a conventional seat belt retractor of this type, in which 200 is an acceleration sensor, 201 is a retractor frame fixed to a seat bag frame, and 203 is connected to a spindle (not shown) for winding up the seat belt. And a steering wheel of a lock mechanism that rotates integrally with the spindle.

  The acceleration sensor 200 is fixed to the retractor frame 201 and tilted integrally with the seat bag. The acceleration sensor 200 is swingably supported by the sensor holder 210 via a swing shaft 215. When the seat back is tilted, By swinging with respect to the sensor holder 210, the mortar-shaped inertial body support surface 223 is always held horizontally and stored in the sensor case 220 in a state of being placed on the inertial body support surface 223. A ball (inertial body) 230 that is displaced from the neutral position when a horizontal acceleration of a predetermined level or more is applied, and a second lever that operates the first lever 250 of the lock mechanism to the lock side by the movement when the ball 230 is displaced. 240. Here, there is a difference in the inertial force when the sensor case 220 and the ball 230 swing, and the sensor case 220 must be operated in accordance with the inclination of the reclining. Operates faster than the ball 230.

According to this seat belt retractor, when a certain acceleration in the horizontal direction acts on the vehicle, the ball 230 is displaced and the second lever 240 is lifted. When the second lever 240 is lifted, the first lever 250 is thereby lifted. When the first lever 250 is lifted, the front end portion of the first lever 250 is engaged with the lock teeth 204 of the steering wheel 203, so that the steering wheel 203 is locked and fixed so that the spindle does not rotate. The belt cannot be pulled out.
JP-A-8-80807 Japanese Patent Laid-Open No. 10-157469

  By the way, in the conventional seat belt retractor shown in FIG. 8, when receiving deceleration in the vehicle traveling direction, the sensor case 220 rotates around the swing shaft 215 in the direction of arrow C due to inertia, as shown in the figure. It will tilt. Therefore, there is no problem in the locking performance when normal deceleration is applied to the vehicle, but in the case of shifting from extremely slow deceleration to sudden deceleration, a delay occurs in the operation timing of the ball 230 and the lock delay is delayed. May come out.

  One cause of the lock delay is that the sensor case 220 swings in the same direction as the ball 230 moves in the sensor case 220 when the vehicle decelerates. This is because the inertial force is reduced. One is that the sensor case 220 is tilted due to the deceleration, so that even if the sensor 230 is further decelerated and the ball 230 tries to move for the operation of the lock mechanism, the ball 230 moves over the tilted inertial support surface 223. This is because it becomes difficult to move in the D direction.

  The present invention has been made in view of the above-described circumstances, and its purpose is to properly lock the seat belt withdrawing operation even when shifting from slow deceleration to sudden deceleration. An object of the present invention is to provide a seatbelt retractor having high sensitivity that operates sensitively to sudden deceleration or collision of a vehicle under traveling conditions.

The above object of the present invention is achieved by the following configurations.
(1) A retractor frame attached to a seat back of a reclining-type vehicle seat, a cover member fixed to the retractor frame, an acceleration sensor that detects horizontal acceleration, and an acceleration detected by the acceleration sensor In accordance with the seat belt retractor provided with a lock mechanism that locks the seat belt pull-out operation accordingly.
The acceleration sensor is
A sensor holder that tilts integrally with the seat back;
A sensor case that is swingably supported by the sensor holder, and that swings relative to the sensor holder when the seat back is tilted, so that the inertia body support surface is always held horizontally;
A first inertial body that is displaced from a neutral position when a horizontal acceleration of a predetermined level or more is applied in a state of being placed on the inertial body support surface;
An actuating member that actuates the lock mechanism to the lock side by movement when the first inertial body is displaced;
A second inertial body that is provided above the first inertial body and moves in response to a horizontal acceleration different from the swinging acceleration of the sensor case;
Case locking means for locking the sensor case to the cover member when the second inertial body moves relative to the sensor case;
A seat belt retractor comprising:
Preferably, the gravity center position of the second inertial body is provided above the gravity center position of the first inertial body.

(2) The case locking means is
The second inertial body supported movably with respect to the sensor case;
An engaged portion provided in the cover member;
A lock portion that is provided on the sensor case and engages the engaged portion when the second inertial body moves, thereby locking the sensor case with respect to the cover member;
The seat belt retractor according to (1), characterized in that
(3) Above the sensor case, a lock lever that is rotatable with the movement of the second inertial body is disposed,
A plurality of locking teeth are provided as the engaged portion along the swinging direction of the sensor case on the upper portion of the cylindrical portion that houses the sensor holder of the cover member,
A lock claw that locks the sensor case with respect to the cover member by engaging the arbitrary lock teeth when the lock lever rotates at the front end portion of the lock lever. Is provided as the lock portion. The seat belt retractor according to (2).
(4) The seatbelt retractor according to (3), wherein the lock lever includes a pair of lock levers disposed on both sides in the moving direction of the second inertial body above the sensor case. .
(5) In the sensor case, the second inertial body, which is set so that the acceleration at which the second inertial body moves is smaller than the acceleration at which the sensor case swings, is moved. The seat belt retractor according to any one of (1) to (4), wherein an inclined surface is provided.
In the present application, the vertical direction means that “down” means a direction approaching the ground with respect to the ground when each inertial body or weight hangs down in its vertical direction, and “up” means a direction away from the ground. In addition, a direction perpendicular to the vertical direction and parallel to the ground is defined as a horizontal direction.

  According to the seat belt retractor of the present invention, the sensor case in which the first inertia body is placed on the inertia body support surface is swingably supported by the sensor holder that tilts integrally with the seat back. Regardless of the reclining angle, the inertial support surface can always be kept horizontal. Therefore, the seat belt drawer can be locked in response to the acceleration appropriately regardless of the reclining angle.

Further, a second inertial body that moves in response to a horizontal acceleration different from the swinging acceleration of the sensor case is provided above the first inertial body, and the second inertial body is provided by the case lock means. As the inertial body moves, the sensor case is locked to the cover member, so the sensor case is fixed in a fixed posture even when the vehicle slowly decelerates and then shifts to sudden deceleration. The condition for displacing the first inertial body does not change. Therefore, for example, even when the vehicle shifts from slow deceleration to sudden deceleration, the seat belt lock delay does not occur.
Here, if the center of gravity of the second inertial body is provided above the position of the center of gravity of the first inertial body, the entire apparatus can be reduced in size.

  Hereinafter, a seat belt retractor according to each embodiment of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is an exploded perspective view of the seat belt of the first embodiment, FIG. 2 is a side view of a reference posture in which a configuration of a main part of the seat belt retractor of FIG. 1 is partially broken, and FIG. 3 is a seat belt of FIG. FIG. 4 is a side view showing a reclining state in which the configuration of the main part of the retractor is partially broken, FIG. 4 is a side view showing a state in operation when there is no case locking means, and FIG. FIG. 6 is a side view showing a partially broken state when the seat belt retractor is operated.

  As shown in FIGS. 1-3, the seatbelt retractor of this embodiment is attached to the seat back S (refer FIG. 2) of the reclining type vehicle seat which can be reclined, and as shown in FIG. The retractor frame 1 is fixed to the seat back S, and a spindle 2 for winding a seat belt (not shown) is rotatably supported on the retractor frame 1. A retractor spring (not shown) that urges the spindle 2 in the seat belt winding direction is connected to one end side of the spindle 2 in the axial direction, and the retractor spring is accommodated in a cover (not shown). Attached to the retractor frame 1.

  On the other end side of the spindle 2 in the axial direction, a steering wheel 3 that is a main element of a lock mechanism that locks the pulling-out operation of the seat belt and a horizontal acceleration acting on the vehicle are detected, and the lock is detected according to the acceleration. And an acceleration sensor 100 that operates the mechanism.

  A cover member (also referred to as a bearing plate) 5 is fixed to the other end side of the retractor frame 1, and the bearing portion of the spindle 2 and the steering wheel 3 are accommodated in the cover member 5. The cylinder part 5a accommodates the acceleration sensor 100. A plurality of lock teeth 5b are provided as engaged portions on the upper edge of the opening of the cylindrical portion 5a of the cover member 5.

  The acceleration sensor 100 includes a sensor holder 10 that tilts integrally with the seat back S, a sensor case 20 that is swingably supported by the sensor holder 10, and a first inertial body that is stored in the sensor case 20. The self-supporting inertial body 30, the first sensor lever 50 and the second sensor lever 40 as the actuating members for locking the lock mechanism by the movement of the self-supporting inertial body 30, and the second supported movably with respect to the sensor case 20. And a pair of lock levers 70 and 71 which are attached to the upper side of the inertia body 60 and the sensor case 20 and are rotatable as the second inertia body 60 moves, and a third attached to the lower side of the sensor case 20. And an inertial body 90. The first sensor lever 50 also serves as an element of a lock mechanism.

  The sensor holder 10 has a pair of substantially fan-shaped side walls 11 and 12 that are spaced apart from each other in parallel, and an opening 19 (see FIG. 2) below the center, and between the arc-shaped outer peripheral edges of the side walls 11 and 12. It has the container shape penetrated up and down with the partial cylindrical wall part 13 to connect. The sensor holder 10 is integrally fixed to the retractor frame 1 by fitting a locking portion 11 a provided on one side wall 11 into the retractor frame 1. The pair of side walls 11 and 12 of the sensor holder 10 are provided with shaft holes 14 for supporting the sensor case 20, and the shaft portions 24 projecting from the sensor case 20 are fitted into the shaft holes 14, so that the sensor case 20 is supported in a vertical plane so as to be swingable in the direction of arrow G in FIG.

  The sensor case 20 includes a container-shaped first sensor case 25 having a peripheral wall 21 and a bottom wall 22, and a second sensor case 80 attached and fixed above the first sensor case 25. In the center of the upper surface of the bottom wall 22 of the first sensor case 25, an inertia body support surface 23 on which the self-supporting inertia body 30 is placed is formed. A third inertia body 90 as a weight is attached to the first sensor case 25 by a gripping claw 26 provided below. Thereby, even when the seat back S is tilted as shown in FIG. 3, the inertia body support surface 23 can be held horizontally at all times by swinging the sensor case 20 with respect to the sensor holder 10. It has become. Holding the inertial body support surface 23 horizontally means that the reference surface of the inertial body support surface 23 (for example, the upper surface of the inertial body support surface 23) is held horizontally.

  The self-supporting inertial body 30 has a substantially cylindrical shape provided with a small-diameter portion 32 having a bottom surface 31 and a large-diameter portion 34 having a mortar-shaped guide surface 33 on the top. The self-supporting inertial body 30 is stored in the first sensor case 25 in a self-supporting state by placing the bottom surface 31 on the inertial body support surface 23 of the first sensor case 20 in a centered state.

  The plane on which the bottom surface 31 of the self-supporting inertial body 30 and the inertial body support surface 23 of the first sensor case 25 are in contact determines the sensitivity of the acceleration sensor 100. The self-supporting inertial body 30 is displaced from the neutral position when it is placed on the inertial support surface 23 and receives a predetermined or higher horizontal acceleration.

  Bearing holes 27 for supporting the second sensor lever 40 are provided at the upper end of the peripheral wall 21 of the sensor case 20, and the base 41 of the second sensor lever 40 is provided in the bearing holes 27 via the shaft pins 27a. Is attached so as to be rotatable in the vertical direction. Further, on one side wall 11 of the sensor holder 10, a support hole 15 for supporting the first sensor lever 50 is provided above the shaft hole 14, and the support hole 15 is interposed via a shaft 51a. A base 51 of the first sensor lever 50 is attached so as to be rotatable in the vertical direction.

  The first sensor lever 50 has a lock claw 52 at the tip, and has a protrusion 53 that protrudes in the direction of the pivot axis at the intermediate portion between the base 51 and the tip that are rotatably supported. The protrusion 53 is slidably mounted on the upper surface of the contact portion 43 of the second sensor lever 40. The first sensor lever 50 is disposed on the lower side of the steering wheel 3 and is lifted upward so that the lock claw 52 engages with the lock teeth 4 of the steering wheel 3 to restrict the rotation of the steering wheel 3. To play a role.

  The second sensor lever 40 has an arm portion 42 that is curved so that the upper surface protrudes upward from the base portion 41, and a tip spherical surface that contacts the guide surface 33 of the self-supporting inertial body 30 is below the arm portion 42. The protrusion 44 has a shape. The upper surface of the arm portion 42 forms an abutting portion 43 slidably abutting on the protrusion 53 of the first sensor lever 50 described above. The second sensor lever 40 is disposed above the self-supporting inertial body 30 and below the first sensor lever 50. When the self-supporting inertial body 30 is displaced from the neutral position, the second sensor lever 40 is lifted upward, The sensor lever 50 is pushed upward. The positions of the rotation axes of the first sensor lever 50 and the second sensor lever 40 are set so that the first sensor lever 50 and the second sensor lever 40 rotate in opposite directions when the self-supporting inertial body 30 is displaced.

  In addition, the second sensor case 80 is configured such that the engaging portion 81 formed below is inserted into the engaged groove 28 formed in the upper portion of the peripheral wall 21 of the first sensor case 25, whereby the first sensor case 25. It is integrally fixed to. The second sensor case 80 is disposed at the same position as the lock teeth 5b of the cover member 5 in the rotation axis direction so as not to interfere with the rotating first and second sensor levers 40, 50. The upper part of the second sensor case 80 above the engaging portion 81 has an inclined surface that is gently inclined in a V shape so that the upper surface is recessed upward so that the second inertial body 60 that is a cylindrical roller moves. The bottom wall 82 (see FIG. 2) formed and a pair of side walls 83 and 84 that are opposed to each other at an interval wider than the axial width of the second inertial body 60, and has a substantially rectangular shape with an upper opening. ing. Support holes 85 and 86 for supporting the pair of lock levers 70 and 71 are provided above both ends of the pair of side walls 83 and 84 in the direction orthogonal to the rotation axis direction. The bases 72 and 73 of the lock levers 70 and 71 are attached to the support holes 85 and 86 through the shafts 85a and 86a so as to be rotatable in the vertical direction. That is, the lock levers 70 and 71 are disposed on both sides in the moving direction of the second inertia body 60.

  Accordingly, the second inertial body 60 supported by the second sensor case 80 is provided above the self-supporting inertial body 30. Note that the gravity center position of the second inertial body 60 may be provided above the gravity center position of the self-supporting inertial body 30.

  The first sensor case 25 is provided with a self-supporting inertial body 30, a second sensor lever 40, and a third inertial body 90. The second sensor case 80 includes a second inertial body 60 and a pair of locks. Lever 70, 71 is provided. For this reason, when the sensor case 20 swings, the whole constitutes one inertial body together with it. Therefore, the weight balance is set so that the inertial body support surface 23 is kept horizontal by the total weight of these.

  The pair of lock levers 70, 71 have lock claws (lock portions) 74, 75 at their tip portions, and a second inertial body is provided at the intermediate portion between the base portions 72, 73 that are rotatably supported and the tip portions. Projections 76 and 77 (refer to FIG. 2) that can come into contact with 60 are provided. When the second inertia body 60 moves in a direction substantially parallel to the vehicle traveling direction along the bottom wall 82 of the second sensor case 80, the pair of lock levers 70, 71 It is designed to rotate in the vertical direction.

  A number of lock teeth 5b of the cover member 5 are provided at a constant pitch in the circumferential direction along a circumference centering on the swing shaft (the shaft portion 24 and the shaft hole 14) of the sensor case 20. These lock teeth 5 b are arranged along the swing direction of the sensor case 20. The lock claws 74 and 75 of the lock levers 70 and 71 engage with the arbitrary lock teeth 5b when the lock levers 70 and 71 are rotated. Therefore, in the present embodiment, the second inertia body 60 movably supported by the bottom wall 82 forming the cylindrical surface of the second sensor case 80, the lock teeth 5b provided on the cover member 5, and the second sensor case The case locking means is configured by the lock claws 74 and 75 of the lock levers 70 and 71 that are provided at 80 and engage with the lock teeth 5b when the second inertial body 60 moves.

  The pivot axis of the sensor case 20, the pivot axis of the first sensor lever 50, the pivot axis of the second sensor lever 40, and the pivot axes of the pair of lock levers 70 and 71 are all pivots of the spindle 2. It is set to face in the horizontal direction parallel to the axis.

  The second inertia body 60 and the bottom wall 82 of the second sensor case 80 that guides and supports the second inertia body 60 move in response to a horizontal acceleration smaller than the swinging acceleration of the sensor case 20. Inertia characteristics are set. That is, the second inertia that is set on the bottom wall 82 of the second sensor case 80 so that the acceleration at which the second inertial body 60 moves is smaller than the acceleration at which the sensor case 20 swings. A V-shaped gentle inclined surface on which the body moves is provided.

Next, the operation of the seat belt retractor of the present embodiment will be described.
When the seat belt retractor is in the reference posture, as shown in FIG. 2, the second inertia body 60 is not moved, and the sensor case 20 holds a constant posture due to its own weight. When the seat back S is in the reclining posture from this state, the sensor holder 10 fixed to the retractor frame 1 tilts integrally with the seat back S, as shown in FIG. At that time, the sensor case 20 swings with respect to the sensor holder 10 by its own weight, and maintains a constant posture so as to hold the inertial body support surface 23 horizontally. Thus, regardless of the reclining angle of the seat back S (including the case of a full flat seat back that tilts the seat back so as to be flat with the seat cushion), the inertial body support surface 23 is always kept horizontal. Therefore, regardless of the reclining angle, the seat belt drawer can be locked in response to the acceleration appropriately.

  Next, when a slow deceleration acts in the vehicle traveling direction, the second inertia is applied in response to the horizontal acceleration smaller than the swinging acceleration of the sensor case 20, as shown in FIG. When the body 60 is displaced in the direction of arrow E, the lock lever 70 is displaced in the direction of arrow K. Then, the lock claw 74 at the tip of the lock lever 70 engages with the lock teeth 5 b of the cover member 5, and the sensor case 20 is locked to the cover member 5. Therefore, as shown in FIG. 4, when there is no case locking means, the sensor case 20 can be prevented from swinging and tilting in the direction of the arrow G1 with a slow deceleration, as shown in FIG. In addition, the sensor case 20 can be fixed in a fixed posture. Therefore, even when the vehicle slowly decelerates and then shifts to sudden deceleration, the conditions for the movement of the self-supporting inertial body 30 in the direction of the arrow H can always be maintained without changing, and hence the sudden deceleration to the sudden deceleration. It is possible to prevent occurrence of a seat belt lock delay when shifting to deceleration.

For example, when a moderate deceleration (brake) of 0.1 to 0.2 G is applied, the lock pawl 74 of the lock lever 70 is engaged with the lock teeth 5 b of the cover member 5 by the movement of the second inertia body 60. Therefore, the level of the sensor case 20 can be maintained at that stage. Therefore, when a large deceleration (for example, 0.3 to 0.4 G) due to sudden braking or a collision is applied thereafter, the self-supporting inertial body 30 is displaced in the sensor case 20 that is maintained level. Normal operation is possible.
When a slow deceleration acts in the vehicle reverse direction, the second inertia body 60 is displaced in the direction opposite to the arrow E direction. For this reason, the lock claw 75 of the lock lever 71 engages with the lock teeth 5b of the cover member 5, and the sensor case 20 is locked to the cover member 5. Similarly, the occurrence of a lock delay can be prevented.

  As described above, according to the seat belt retractor of the present embodiment, the sensor case 20 storing the self-supporting inertial body 30 that is the first inertial body swings on the sensor holder 10 that tilts integrally with the seatback S. Since it is supported so as to be movable, the inertial support surface 23 can be always kept horizontal regardless of the reclining angle of the seat back S. Therefore, the seat belt drawer can be locked in response to the acceleration appropriately regardless of the reclining angle.

A second inertia body 60 that moves in response to a horizontal acceleration smaller than the swinging acceleration of the sensor case 20 is provided. When the second inertia body 60 moves, the sensor case 20 is locked to the cover member 5 by the case locking means. Therefore, when the vehicle slowly decelerates and then shifts to sudden deceleration. However, the sensor case 20 can be fixed in a fixed posture, and the conditions for the displacement of the self-supporting inertial body 30 do not change. Therefore, even when the vehicle shifts from slow deceleration to sudden deceleration, the seat belt lock delay does not occur.
Further, since the second inertia body 60 has a center of gravity position above the center of gravity of the self-standing inertia body 30 (first inertia body), the vertical dimension of the seat belt retractor can be reduced.
Furthermore, since the second inertia body 60 has a cylindrical roller shape, inertia mass can be obtained without increasing the dimension in the rotation axis direction as compared with the ball shape.

  Further, according to the seat belt retractor of the present embodiment, the case lock means includes the second inertia body 60 that is supported movably with respect to the sensor case 20, the lock teeth 5b provided on the cover member 5, and the sensor. Lock claws 74 and 75 that are provided in the case 20 and lock the sensor case 20 with respect to the cover member 5 by engaging the lock teeth 5b when the second inertial body 60 moves. Therefore, the sensor case 20 can be reliably locked with a simple configuration.

  In addition, the seat belt retractor of the present embodiment has a pair of lock levers 70 and 71 disposed on both sides in the moving direction of the second inertial body 60 above the sensor case 20, so that the lock levers 70 and 71 are Since the vehicle is divided into two parts, the forward direction and the reverse direction, and the weight is reduced, the operation can be stabilized with respect to the acceleration in each direction, and the sensor sensitivity can be improved. Thereby, the 2nd inertial body 60 can also be made thin in a rotating shaft direction, and the whole apparatus can be reduced in size.

  Further, according to the seat belt retractor of the present embodiment, by providing a gentle inclined surface on which the second inertia body 60 moves on the bottom wall 82 of the second sensor case 80, the sensor case 20 can be configured with a simple configuration. The acceleration at which the second inertial body 60 moves can be set smaller than the oscillating acceleration.

(Second Embodiment)
Next, a seat belt retractor according to a second embodiment of the present invention will be described with reference to FIGS. In addition, about the equivalent part to 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  In the seat belt retractor of the first embodiment, the pair of lock levers 70 and 71 are used. However, in the seat belt retractor of the present embodiment, the single lock lever 110 having the pair of arm portions 111 and 112 is used instead. Used for. A pair of side walls 83 and 84 of the second sensor case 80 is provided with a support hole 87 above an intermediate portion in a direction orthogonal to the rotation axis direction, and a lock lever is provided in the support hole 87 via a shaft 87a. A base 113 of 110 is rotatably attached. Further, the arm portions 111 and 112 of the lock lever 110 have lock claws 114 and 115 at the tip portions, respectively. A cylindrical surface 113 a that is recessed upward is formed on the lower surface of the base portion 113 so as to follow the outer peripheral surface of the second inertial body 60 located in the middle portion of the bottom wall 82.

  Therefore, in the seat belt retractor configured as described above, as in the first embodiment, the inertia body support surface 23 is always kept horizontal, and the sensor case 20 is locked when a moderate deceleration is applied. Can do.

That is, in the case where a slow deceleration acts in both the forward direction and the reverse direction of the vehicle, the second inertial body responds to the horizontal acceleration smaller than the swinging acceleration of the sensor case 20. 60 is displaced and contacts the edge of the cylindrical surface 113a of the lock lever 110. As a result, the lock lever 110 rotates and the lock claws 74 and 75 of one of the arm portions 111 and 112 engage with the lock teeth 5 b of the cover member 5, thereby locking the sensor case 20 to the cover member 5. To do. Therefore, even when the vehicle slowly decelerates and then shifts to sudden deceleration, the sensor case 20 can be fixed in a fixed posture, and the conditions for displacing the self-supporting inertial body 30 do not change. .
Other configurations and operations are the same as those in the first embodiment.

  In addition, this invention is not limited to embodiment mentioned above, A deformation | transformation, improvement, etc. are possible suitably. In addition, the material, shape, dimensions, number, arrangement location, and the like of each component in the above-described embodiment are arbitrary and are not limited as long as the present invention can be achieved.

  For example, although the case where the first inertial body is the self-supporting inertial body 30 has been described in the above embodiment, the present invention can be applied to a case where a ball is used in addition to the self-supporting inertial body.

  Moreover, in the said embodiment, although the case where the sensor case 20 was comprised by the 1st and 2nd sensor cases 25 and 80 was shown, you may form by a single member.

  Furthermore, in the above embodiment, the bottom wall 82 of the second sensor case 80 is provided with a gently inclined surface on which the second inertial body 60 moves, but it may be a gently arcuate surface. Therefore, the movement of the second inertial body 60 of the present invention includes a case where it swings.

It is a disassembled perspective view of the seatbelt retractor of 1st Embodiment of this invention. FIG. 2 is a side view of a reference posture showing a partially broken configuration of a main part of the seat belt retractor of FIG. 1. FIG. 2 is a side view of a reclining state in which a configuration of a main part of the seat belt retractor of FIG. 1 is partially broken. It is a side view which shows the state at the time of the action | operation when there is no case locking means partially fractured | ruptured. FIG. 2 is a side view showing a partially broken state of the seat belt retractor of FIG. 1 during operation. It is a side view of the structure of the principal part of the seatbelt retractor of 2nd Embodiment of this invention. FIG. 7 is a side view showing a partially broken configuration of a main part of the seat belt retractor of FIG. 6. It is a side view which shows a state when the acceleration sensor of the conventional seatbelt retractor receives gentle deceleration.

Explanation of symbols

3 Steering wheel (lock mechanism)
5 Cover member 5b Lock tooth (engaged part, case lock means)
10 sensor holder 20 sensor case 23 inertial body support surface 25 first sensor case 30 self-supporting inertial body (first inertial body)
40 Second sensor lever (actuating member)
50 First sensor lever (locking mechanism, actuating member)
60 Second inertial body (case lock means)
70, 71, 110 Lock lever (case lock means)
74,75 Lock claw (lock part, case lock means)
80 Second sensor case 90 Third inertial body 100 Acceleration sensor S Seat back

Claims (5)

A retractor frame attached to a seat back of a reclining vehicle seat, a cover member fixed to the retractor frame, an acceleration sensor for detecting a horizontal acceleration, and a seat according to the acceleration detected by the acceleration sensor In a seat belt retractor provided with a lock mechanism that locks the belt drawing operation,
The acceleration sensor is
A sensor holder that tilts integrally with the seat back;
A sensor case that is swingably supported by the sensor holder, and that swings relative to the sensor holder when the seat back is tilted, so that the inertia body support surface is always held horizontally;
A first inertial body that is displaced from a neutral position when a horizontal acceleration of a predetermined level or more is applied in a state of being placed on the inertial body support surface;
An actuating member that actuates the lock mechanism to the lock side by movement when the first inertial body is displaced;
A second inertial body that is provided above the first inertial body and moves in response to a horizontal acceleration different from the swinging acceleration of the sensor case;
Case locking means for locking the sensor case to the cover member when the second inertial body moves relative to the sensor case;
A seat belt retractor comprising: The case locking means is
The second inertial body supported movably with respect to the sensor case;
An engaged portion provided in the cover member;
A lock portion that is provided on the sensor case and engages the engaged portion when the second inertial body moves, thereby locking the sensor case with respect to the cover member;
The seat belt retractor according to claim 1, comprising: Above the sensor case, a lock lever that is rotatable in accordance with the movement of the second inertial body is disposed,
A plurality of locking teeth are provided as the engaged portion along the swinging direction of the sensor case on the upper portion of the cylindrical portion that houses the sensor holder of the cover member,
A lock claw that locks the sensor case with respect to the cover member by engaging the arbitrary lock teeth when the lock lever rotates at the front end portion of the lock lever. The seat belt retractor according to claim 2, wherein the seat belt retractor is provided as the lock portion.   4. The seat belt retractor according to claim 3, wherein the lock lever includes a pair of lock levers disposed on both sides in the moving direction of the second inertial body above the sensor case. 5.   The sensor case has an inclined surface on which the second inertial body moves so that an acceleration at which the second inertial body moves is smaller than an acceleration at which the sensor case swings. The seat belt retractor according to claim 1, wherein the seat belt retractor is provided.

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