JP3768657B2 - Body acceleration sensor for seat belt - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle body acceleration sensor for a seat belt, and more particularly to a seat belt used in a seat belt retractor mounted in a seat back of a reclining seat of a vehicle or the like and operating a locking means for preventing webbing from extending in an emergency. It is related with the improvement of the vehicle body acceleration sensor.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a seat belt device for safely holding a vehicle occupant or the like in a seat is equipped with an emergency lock mechanism that physically locks a retractor by inertial sensing means that reacts to sudden acceleration, collision or deceleration. An emergency lock type retractor is used which effectively and safely restrains the webbing and reduces the feeling of pressure caused by webbing.
[0003]
As an inertia sensing means used for such an emergency lock type retractor, there is a vehicle body acceleration sensor for sensing the acceleration of the vehicle body. For example, when the inertial body moves due to collision or inclination of the vehicle body, the vehicle body acceleration sensor swings the sensor arm provided on the inertial body and rotates the winding shaft around which the webbing is wound in the webbing pull-out direction. It is the structure which operates the locking means to lock.
[0004]
In recent years, various kinds of vehicle body acceleration sensors for seat belts have been proposed in which the retractor as described above is mounted in the seat back (seat backrest) of a reclining seat of a vehicle or the like and can be operated similarly even if the inclination of the seat back is changed. ing.
Such a vehicle body acceleration sensor is provided with a retractor-based sensor case provided with the inertial body support surface so that the orientation of the inertial body support surface that supports the inertial body is properly maintained regardless of the inclination state of the seat back. When the seatback tilt state is changed, the sensor case is rotated to correct the direction of the inertial body support surface, and the sensor case is rotated. Ingenuity has been devised in the mechanism and the equipment configuration of the sensor arm.
[0005]
For example, in a vehicle body acceleration sensor disclosed in JP-A-8-80807, etc., the sensor case is attached to the retractor base so that the rotation axis of the sensor case passes through the center of a ball weight that is an inertial body, and the sensor case The center of gravity of the sensor case is set below the rotation axis so that the sensor case always faces in the vertical direction due to its own weight.
Further, as in a vehicle body acceleration sensor disclosed in JP-A-1-202553, US Pat. No. 5,622,383, and the like, a rotation transmission that rotates the sensor case in conjunction with the change in the tilted state of the seat back. Various proposals have been made in which the means is disposed between the sensor case and the sheet metal fitting, and the orientation of the sensor case is corrected by the rotation transmitting means when the inclination state of the seat back is changed.
[0006]
On the other hand, in the vehicle body acceleration sensor disclosed in US Pat. No. 5,622,383, etc., the sensor arm that swings due to the movement of the inertial body on the sensor case is a single sensor type, so-called single arm type. It is rotatably attached to the tractor base, and when it swings, its tip is engaged with the teeth of the ratchet wheel to actuate the retractor locking means. In general, such a single arm type is widely used. However, in the vehicle body acceleration sensor disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 1-202553, etc., a first sensor arm that swings by movement of an inertial body, There is also a so-called double arm type that uses two sensor arms having a second sensor arm that is driven by the swinging motion of the first sensor arm to actuate the locking means.
[0007]
[Problems to be solved by the invention]
By the way, in the vehicle body acceleration sensor disclosed in JP-A-8-80807 and the like that realizes the rotation of the sensor case by the weight of the sensor case itself, the sensor case swings in the longitudinal direction of the vehicle body when the vehicle suddenly decelerates. On the other hand, there is a possibility that the difference in inertia force between the inertial body and the sensor case becomes small, and the sensor case moves together with the inertial body, resulting in a decrease in acceleration sensitivity.
[0008]
On the other hand, as in the case of the vehicle body acceleration sensor disclosed in the above-mentioned JP-A-1-202553 and US Pat. No. 5,622,383, a dedicated sensor for rotating the sensor case in conjunction with the tilting of the seat back. In the device equipped with the rotation transmission means, the sensor case itself can be prevented from rotating due to the acceleration acting upon sudden deceleration of the vehicle, and the acceleration sensitivity can be prevented from being lowered due to the swing of the sensor case.
However, in the single arm type in which the locking means is operated by a single sensor arm rotatably attached to the retractor base, the ground angle of the sensor arm fluctuates due to a change in the inclination state of the seat back, and the sensor arm Since the engaging part is directed upward or downward, the influence of the inertial mass of this part on the acceleration differs depending on the tilted state of the seat back, which may affect the acceleration sensitivity.
[0009]
On the other hand, the double arm type as disclosed in the above Japanese Laid-Open Patent Publication No. 1-202553 can avoid the inconvenience that fluctuations in the ground angle of the sensor arm affect the acceleration sensitivity. Although it can be stabilized, on the other hand, there has been a problem that an increase in the number of parts and a complicated mechanism cause an increase in manufacturing cost.
[0010]
Accordingly, an object of the present invention is to solve the above-mentioned problems, and is a vehicle body acceleration sensor equipped in a retractor mounted in a seat back, which can stably detect the acceleration of the vehicle body stably. Moreover, it is an object of the present invention to provide a satisfactory vehicle body acceleration sensor for a seat belt capable of reducing the manufacturing cost with a simple mechanism.
[0011]
[Means for Solving the Problems]
The above object of the present invention is to provide a sensor case that is supported by a retractor base so as to be rotatable about a rotation axis of a take-up shaft of a retractor for a seat belt provided on a seat back of a reclining seat such as a vehicle, The sensor case is rotatably attached so that a first position for operating the locking means for locking the rotation of the winding shaft in the webbing pull-out direction and a second position for not operating the locking means can be taken. A sensor arm that engages with the ratchet wheel of the locking means rotatably attached to the take-up shaft at the first position and does not engage at the second position, and receives a speed change of a predetermined value or more. an inertial body support surface above the sensor case relative movement between the inertial body to move the sensor arm in the first position, the seat back The slide member varying the change in the tilt angle into a linear movement and near the bottom of the sensor case coupled with flexible transmission member instead of the linear movement of the change in the tilt angle of the seat back is transmitted to the sensor casing, Rotation transmission that links the sensor case around the rotation axis of the take-up shaft in accordance with the inclination angle of the seat back so that the direction of the inertial support surface is kept horizontal regardless of the inclination state of the seat back. And a vehicle body acceleration sensor for a seat belt that operates the locking means by moving the inertial body when a predetermined vehicle body acceleration is applied.
[0012]
According to the above configuration, when the inclination state of the seat back is changed, the sensor case is rotated by the rotation transmitting means interlocking with the inclination of the seat back, and the inertial support surface is maintained in an appropriate state.
The sensor case to which the sensor arm is rotatably attached is configured to rotate about the rotation axis of the retractor take-up shaft. Therefore, when the inclination of the seat back is changed, the take-up shaft rotates. The sensor case rotates so as to follow the inertia member arranged so as to be rotatable about the axis while maintaining a constant interval.
Therefore, the distance between the engagement portions of the sensor arm and the inertia member does not change, and the ground angle of the sensor arm is always kept constant.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a vehicle body acceleration sensor for a seat belt according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
As shown in FIG. 1, the seat belt retractor 100 including the vehicle body acceleration sensor 32 according to the present embodiment is attached to a seat back 62 of a reclining seat 61 attached to the vehicle body. The seat back 62 is connected to the seat seat portion 63 so as to be pivotable around an adjustment shaft (adjustment axis of the seat back) 71 extending in the vehicle body width direction. The tilt state is adjusted.
[0014]
2 and 3, the seat belt retractor 100 is rotatably supported on the retractor base 1 through the substantially cylindrical bobbin 2 around which the webbing 70 is wound, and the bobbin 2 being inserted. In addition, a winding shaft 4 provided with a latch plate 4a which is a claw wheel on the end side (right side in FIG. 3), and an emergency lock for preventing rotation of the latch plate 4a in the pull-out direction of the webbing 70 in the event of a vehicle emergency Mechanism 300. The webbing 70 extending from the retractor 100 through the slot 64 formed in the seat back 62 restrains the occupant to the seat.
[0015]
The retractor base 1 fixed to a frame member (not shown) of the seat back 62 is formed by pressing a metal plate so that most of the retractor base 1 has a U-shaped cross section. , 1b, a winding shaft 4 combined with the bobbin 2 is bridged rotatably. A known winding spring device that constantly urges the bobbin 2 in the winding direction of the webbing 70 via the winding shaft 4 at the other end of the winding shaft 4 inserted through the side plate lb of the retractor base 1. (Not shown).
[0016]
In the present invention, various known structures can be adopted as the specific configuration of the emergency lock mechanism 300 that restrains the rotation of the winding shaft 4 in the webbing pull-out direction in the event of a vehicle emergency. For example, in the case of this embodiment, the ratchet wheel 19 that is an inertia member arranged to be rotatable about the rotation axis S of the winding shaft 4 causes a rotation delay with respect to the winding shaft 4, thereby latching. The cup 13 engages the pole 11 with the latch plate 4a and prevents the winding shaft 4 from rotating in the webbing pull-out direction.
[0017]
A vehicle body acceleration sensor 32 according to the present invention is mounted below the ratchet wheel 19.
As shown in FIGS. 2 and 3, the seatbelt vehicle body acceleration sensor 32 of the present embodiment includes a sensor arm 31, a sensor case 30, an inertial body 33, and a rotation transmission means 39.
[0018]
The sensor case 30 includes a case body 30a having an inertia body support surface 30b on which the inertia body 33 is placed, and a hanger portion 30c extending upward from one side of the case body 30a. The upper end of the hanger portion 30c is rotatably connected to the end portion of the winding shaft 4 via a pin 35. Here, the central axis of the pin 35 coincides with the rotation axis S of the winding shaft 4, and the rotation axis of the sensor case 30 extends in parallel with the adjustment shaft 71 of the seat back 62. It is made to correspond to the rotation axis S of the spindle 4. However, the retractor may be a case where the upper end of the base is tilted in the YY direction with reference to the base mounting hole 1c in FIG. 3, and the adjusting shaft 71 and the winding shaft 4 intersect at a predetermined angle and are not parallel. In this case, the sensor 32 may be mounted so as to take the state shown in FIG. 3 even when the base is inclined at a predetermined angle.
[0019]
The inertia body support surface 30b of the sensor case 30 has a mortar shape that is recessed toward the center, and the bottom of the case body 30a equipped with the inertia body support surface 30b is connected to a rotation transmission means 39 described later. A connecting portion 51 in which a long hole 50 is formed is suspended.
[0020]
The sensor arm 31 has a base end side shaft portion 31a rotatably supported by a support column formed integrally with the case body 30a of the sensor case 30. The sensor case 30 is attached to a retractor via a pin 35. In the state, the engaging portion 31b engages with the teeth 19a of the ratchet wheel 19 to activate the locking means that locks the rotation of the winding shaft 4 in the webbing pull-out direction from the first position. The shaft 31a can be swung and displaced about the shaft 31a to a second position where the lock 31b is not operated by separating from the tooth 19a. The “locking means” in the present invention means one obtained by removing the vehicle body acceleration sensor 32 from the emergency locking mechanism 300.
[0021]
Therefore, when the engaging portion 31b of the sensor arm 31 engages with the teeth 19a of the ratchet wheel 19, the ratchet wheel 19 is delayed in rotation with respect to the winding shaft 4, and the pole 11 is latched via the latch cup 13. Engagement with the plate 4a prevents the winding shaft 4 from rotating in the webbing 70 withdrawing direction.
[0022]
The inertial body 33 has a spherical shape. When the inertial body 33 is placed on the inertial body support surface 30b and receives a change in speed of a predetermined level or more, the inertial body 33 moves relative to the inertial body support surface 30b and circumscribes the inertial body 33. The sensor arm 31 is moved to the first position.
[0023]
The rotation transmitting means 39 is responsive to the inclination angle of the seat back 62 so that the direction of the inertial body support surface 30b is kept appropriate (vertically upward) regardless of the inclination state of the seat back 62. The sensor case 30 is rotated around its rotation axis S. Note that the sensor case 30 connected to the rotation transmitting means 39 does not rotate around the rotation axis S due to an inertial force that acts when the vehicle collides.
[0024]
As shown in FIG. 1, the rotation transmission means 39 is centered on a slide member 53 disposed on a seat seat 63 of a reclining seat 61 so as to be linearly movable along the longitudinal direction of the vehicle, and an adjustment shaft 71. A cam plate 54 that is rotated to move the slide member 53 forward and backward within a predetermined range corresponding to the rotatable range of the sensor case 30 in accordance with the tilted state of the seat back 62, and one end connected to the slide member 53. The other end is connected to the connecting portion 51 of the sensor case 30 and includes a wire 56 as a flexible transmission member that transmits the movement of the slide member 53 to the sensor case 30. The wire 56 has one end fixed to the vicinity of the mounting position of the slide member 53 via a fixing portion 55a and the other end fixed to 1 in the seat back 62. 55 is inserted through.
[0025]
In the rotation transmission means 39 described above, the cam plate 54 rotates around the adjustment shaft 71 integrally with the seat back 62 while the seat back 62 is tilted to the maximum extent within the seat belt usage range. The rotation of the cam plate 54 rotates the sensor case 30 via the slide member 53 and the wire 56, so that the inertial body support surface 30b is directed upward in the vertical direction.
Further, when the seat back 62 is tilted back and forth (that is, when the seat belt is out of the use range), the rotation transmission means 39 does not rotate the sensor case 30.
[0026]
Therefore, according to the vehicle body acceleration sensor 32 of the present embodiment, when the inclination state of the seat back 62 is changed, the sensor case 30 is rotated by the rotation transmission means 39 that is interlocked with the inclination of the seat back 62, and inertia is achieved. The body support surface 30b is maintained in an appropriate state. Therefore, even if the tilting state of the seat back 62 is changed, the sensor case 30 is maintained in a good posture, and only the inertial body 33 on the sensor case 30 moves with an inertial force due to an impact in the event of a vehicle emergency. Therefore, the sensor sensitivity is not slowed down, and the acceleration of the vehicle body can be sensed stably and reliably.
[0027]
Further, the sensor case 30 to which the sensor arm 31 is rotatably attached is configured to rotate around the rotation axis S of the winding shaft 4, so that when the seat back 62 is inclined, the winding is performed. The sensor case 30 is rotated so as to follow a tooth 19a of a ratchet wheel 19 disposed so as to be rotatable about a rotation axis S of the shaft 4 while maintaining a constant interval.
[0028]
That is, in the vehicle body acceleration sensor 32, the distance between the engagement portions 31b of the sensor arm 31 with respect to the teeth 19a of the ratchet wheel 19 does not change, and the ground angle of the sensor arm 31 is always kept constant. Therefore, although the sensor arm 31 is a so-called single arm type that requires only a single arm, the acceleration sensitivity is not affected by the inclined state of the seat back 62. The case body 30a, the sensor arm 31, and the inertial body 33 assembled as the sensor case 30 can be the same as those used in a general vehicle acceleration sensor in which the retractor is fixed to the vehicle body.
[0029]
Therefore, the acceleration of the vehicle body can be sensed stably and reliably, and the increase in the number of parts and the complexity of the mechanism can be prevented, and the manufacturing cost can be reduced.
The configurations of the locking means, sensor arm, sensor case, inertial body, and rotation transmitting means in the present invention are not limited to the configuration of the above embodiment, and can be appropriately changed based on the gist of the present invention. Needless to say.
[0030]
【The invention's effect】
According to the vehicle body acceleration sensor for seat belts of the present invention, when the inclination state of the seat back is changed, the sensor case is rotated by the rotation transmitting means interlocking with the inclination of the seat back, and the inertia body support surface is properly set. Maintained. Therefore, even if the seatback tilting state is changed, the sensor case remains in a good posture, and only the inertial body on the sensor case moves with the inertial force due to impact in the event of a vehicle emergency. Sensitivity can be sensed stably and reliably without any loss of sensitivity.
[0031]
In addition, since the sensor case to which the sensor arm is rotatably attached is configured to rotate about the rotation axis of the take-up shaft, the rotation axis of the take-up shaft 4 is changed when the inclination of the seat back is changed. The sensor case rotates so as to maintain a constant distance with respect to an inertia member arranged to be rotatable around the center.
That is, the distance between the engagement portions of the sensor arm with respect to the inertia member does not change, and the ground angle of the sensor arm is always kept constant. Therefore, even though the sensor arm is a so-called single arm type that requires only a single arm, the acceleration sensitivity is not affected by the tilted state of the seat back.
Therefore, the seat belt vehicle body acceleration sensor of the present invention can stably and reliably detect the vehicle body acceleration, and also prevents the increase in the number of parts and the complexity of the mechanism, thereby reducing the manufacturing cost. Can do.
[Brief description of the drawings]
FIG. 1 is a side view of a reclining seat equipped with a seat belt retractor having a vehicle body acceleration sensor according to an embodiment of the present invention.
FIG. 2 is a side view of the seat belt retractor shown in FIG.
FIG. 3 is a longitudinal sectional view of an essential part of the seat belt retractor shown in FIG. 2;
4 is a side view of the seatbelt retractor in a state in which the seat back of the reclining seat shown in FIG. 1 is tilted backward. FIG.
5 is a side view of the seatbelt retractor in a state in which the seat back of the reclining seat shown in FIG. 1 is tilted forward. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Retractor base 2 Bobbin 4 Rewinding shaft 19 Ratchet wheel 11 Pole 30 Sensor case 30b Inertial body support surface 31 Sensor arm 32 Seat belt vehicle body acceleration sensor 33 Inertial body 39 Rotation transmission means 56 Wire 61 Reclining seat 62 Seat back 63 Seat seat 70 Webbing 100 Seat belt retractor

Claims (1)

A sensor case supported on a retractor base so as to be rotatable about a rotation axis of a take-up shaft of a retractor for a seat belt provided on a seat back of a reclining seat such as a vehicle;
The sensor case is rotatably attached so that a first position for operating the locking means for locking the rotation of the winding shaft in the webbing pull-out direction and a second position for not operating the locking means can be taken. A sensor arm that engages with the ratchet wheel of the locking means rotatably attached to the winding shaft in the first position and does not engage in the second position ;
An inertial body that relatively moves on an inertial body support surface of the sensor case upon receiving a speed change of a predetermined value or more, and moves the sensor arm to the first position;
The sensor case is configured by connecting a slide member that changes a change in the inclination angle of the seat back to a linear movement and a vicinity of the bottom of the sensor case with a flexible transmission member, thereby changing the change in the inclination angle of the seat back to a linear movement. The sensor case is rotated around the rotation axis of the take-up shaft according to the inclination angle of the seat back so that the orientation of the inertial body support surface is kept horizontal regardless of the inclination state of the seat back. A vehicle body acceleration sensor for a seat belt that includes a rotation transmission unit that is interlocked, and that operates the locking unit by a movement operation of the inertial body when a predetermined vehicle body acceleration is applied.

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