JPH11165611A - Retractor for seat belt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seat belt retractor of high reliability in which a locking means is actuated properly upon sensing the acceleration of a car body certainly even when a seat back is in different tilting position. SOLUTION: A seat belt retractor 100 to be installed in a seat back is equipped with a lock arm 5 to actuate a locking means 18, sensing means 37 and 51 for actuating the lock arm 5, and a regulating means 39 which regulates the directions of the sensing means 37 and 51 properly in accordance with the seat back tilting condition, wherein the sensing means 37 and 51 rotate around a winding shaft, and the butting surface of the lock arm 5 with the sensing means 51 consists of a circular arced surface 5a having an approx. radius of curvature R based on the length from the center of the winding shaft to the abutting part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a seat belt retractor provided in a seat back and having an emergency lock mechanism.

[0002]

2. Description of the Related Art Conventionally, a seat belt device for safely holding a vehicle occupant or the like in a seat includes an emergency lock that physically locks a retractor by inertial sensing means that responds to sudden acceleration, collision or deceleration. Emergency locking retractors with mechanisms to effectively and safely restrain occupants are used.

Further, as an inertial sensing means used in such an emergency lock type retractor, there is a vehicle body acceleration sensor for detecting vehicle body acceleration. For example, when the inertial body moves due to a collision of the vehicle body, the vehicle body acceleration sensor swings a sensor arm provided on the upper part of the inertial body to lock the rotation of the winding shaft on which the webbing is wound in the webbing pulling-out direction. It is the structure which operates the lock means which performs.

In recent years, the above-mentioned retractor is mounted in a seat back (seat back) of a reclining type seat of a vehicle or the like, and the vehicle body acceleration sensor for a seat back can be operated even when the inclination angle of the seat back is changed. Has been proposed. For example, JP-A-3-14835
The vehicle acceleration sensor disclosed in Japanese Patent Application Publication No. 0-77-122 maintains the orientation of the inertial support on the sensor case in a freely rotatable manner on the retractor base regardless of the inclination of the seat back. A flexible shaft is arranged between the sensor case and the sheet metal fitting so that the sensor case is interlocked around its rotation axis in accordance with the inclination angle of the seat back so as to lean.

[0005]

However, the vehicle acceleration sensor disclosed in Japanese Patent Application Laid-Open No. 3-148350 is such that the sensor swings around an axis near the position where the sensor arm and the ratchet wheel are engaged. When the position of the sensor is changed by tilting the seat back, the contact (contact angle) between the tip of the sensor arm and the ratchet wheel changes. If the contact is changed, there is a possibility that the sensor arm cannot stop the ratchet wheel at the predetermined position and the lock mechanism cannot function normally.

For example, when the ratchet wheel provided on the winding shaft is stopped from rotating and the winding shaft is relatively rotated, the lock member provided on the winding shaft is engaged with the engaging teeth provided on the retractor base. In the locking means having a configuration that matches, if the phases of the engaging teeth of the retractor base for setting the locking position and the engaging teeth of the ratchet wheel are not constant, the operation timing of the locking means changes. In the configuration in which the lock is locked by engaging the lock member with any of the engagement teeth continuously provided on the retractor base, when the operation timing of the lock member changes,
The locking member does not reach the position where it should originally be engaged, resulting in insufficient engagement. If the winding shaft is forcibly rotated to make this engagement sufficient, an excessive force acts on a sensor arm or the like, which is not preferable. Therefore, an object of the present invention is to solve the above-described conventional problems, and it is possible to reliably detect the acceleration of the vehicle body even when the seat back is at a different tilt position and to obtain a highly reliable locking means that operates properly. An object of the present invention is to provide a retractor for a belt.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a locking means for locking the rotation of a winding shaft in a webbing pull-out direction, and a locking means which is rotatably mounted on a retractor base and operates the locking means. A lock arm, a sensing means rotatably mounted on the retractor base, which senses a predetermined acceleration to actuate the lock arm, and appropriately adjusting the orientation of the sensing means according to the inclination of the seat back. A seat belt retractor built in the seat back, wherein the sensing means is supported so as to rotate about the winding shaft, and the lock arm contacts the sensing means. This is achieved by a seat belt retractor, wherein the contact surface is an arc surface having a length from the center of the winding shaft to the contact portion with a substantially radius of curvature. That. Further, the sensing means is supported so as to rotate about an inertial body provided therein, and a contact surface of the lock arm with the sensing means has a length substantially equal to the center of the inertial body and a contact portion. An arc surface having a radius of curvature may be used.

According to the above construction of the present invention, the contact surface of the lock arm with the sensing means is an arc surface having a length from the center of the winding shaft or the center of inertia to the contact portion with a substantially radius of curvature. Therefore, even if the direction of the sensing means is adjusted and the relative position with the locking means changes, the position of the lock arm supported in contact with the sensing means does not change, and the relative position between the lock arm and the locking means is changed. does not change. Therefore, even if the seat back is tilted and the sensing means is adjusted to the proper position,
The position of the lock arm that operates the locking means does not change, and a reliable locking operation can be guaranteed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a schematic side view of a reclining type seat to which a seat belt retractor according to an embodiment of the present invention is attached. As shown in FIG. 1, a seatbelt retractor 10 having a vehicle body acceleration sensor 51 as a sensing means in the present invention.
0 is a reclining seat 6 attached to the vehicle body
It is attached to the inside 62 of one seat back. The seat back 62 is connected to the seat portion 63 so as to be able to pivot about an adjustment shaft 71 extending in the vehicle width direction, and the inclination angle is adjusted according to the physique and the like of the occupant.

FIGS. 2 and 3 are exploded perspective views of the seat belt retractor 100. FIG. As shown in FIGS. 2 and 3, the retractor base 1 has a substantially U-shaped cross section, and winding shaft through holes are formed in the opposing side plates 1a and 1b, respectively. The bobbin 3 which is a winding shaft for winding the shaft is rotatably mounted with the bobbin 3 inserted through these winding shaft through holes.

On the inner peripheral edge of the winding shaft through hole provided in the side plate 1a, engagement internal teeth 2 constituting locking means are formed, and a ring member 4 is provided outside the winding shaft through hole. It is juxtaposed. Around the engagement internal teeth 2 of the side plate 1a, there is provided an outer peripheral surface 5a formed of an arc surface having a substantially radius of curvature R concentric with the center of the bobbin 3, and the side plate 1a is rotatable about a pin 5b. And an adjusting means 39 for appropriately adjusting the position of the vehicle body acceleration sensor 51. Further, a known take-up spring device 15 is disposed on the side plate 1b of the base, and the bobbin 3 is constantly urged in a direction in which the webbing is taken up.

The bobbin 3 is a winding shaft having a substantially cylindrical shape. A slit 28a is formed in a body 28 around which the webbing is wound. Is provided. And bobbin 3
A flange member 13 formed separately is attached to the outer periphery of the webbing to prevent the webbing from being disturbed. The webbing wound around the bobbin 3 assembled to the retractor base 1 has its webbing guide 41 attached to the upper portion on the back plate side of the retractor base 1 inserted therethrough, thereby restricting the entry and exit positions. .

A rotary support shaft for rotatably supporting the bobbin 3 protrudes from both end surfaces of the bobbin 3, and a support shaft pin formed separately on the sensor-side end surface of the bobbin 3. 6 is press-fitted as a rotating shaft. On the sensor-side end surface of the bobbin 3, a support shaft 7 that swingably supports a pawl 16 that constitutes a lock unit that can be engaged with the engagement internal teeth 2 is protruded.

At the swinging end of the pole 16, a side plate 1a is provided.
Teeth 16c engageable with the engagement inner teeth 2 configured as described above.
Are integrally formed. A shaft hole 16a for loosely fitting to the support shaft 7 is provided through the center of the pole 16, and an engagement protrusion 16b located on the swinging end side and a pole 16a are formed on the sensor side surface of the pole 16. A pressing projection 16d located on the side of the rear end 16e protrudes. The shaft hole 16a
Is loosely fitted to the support shaft 7, the pawl 16 is pivotally supported on the support shaft 7 so as to be swingable and movable by a predetermined amount. An end of the engaging projection 16b of the pawl 16 is inserted into a cam hole 18a formed in a ratchet wheel 18 which constitutes a lock means rotatably supported by the support pin 6.

The ratchet wheel 18 is a ratchet wheel whose center hole is rotatably supported by the support pin 6. A ratchet tooth 18b for engaging with the lock arm 5 is formed on the outer peripheral portion. Have been. Further, the flange portion 6a of the spindle pin 6 axially supports a center hole 30a of an inertia plate 30, which is a disk-shaped inertial member for sensing the webbing withdrawal acceleration.

A gear lock arm 26 is attached to the projection 22 of the ratchet wheel 18. The gear lock arm 26 is provided with an engagement claw 26b that can mesh with the internal gear 34a of the gear case 34, and an arm 26c that presses a central portion in the longitudinal direction of the linear sensor spring 25. Accordingly, the gear lock arm 26 constitutes a locking member that prevents the ratchet wheel 18 from rotating in the webbing pull-out direction by engaging the engagement claw 26b with the internal gear 34a that is the engaged portion.

At the center of a gear case 34 disposed outside the inertia plate 30, a shaft support portion 34b for rotatably supporting the bobbin 3 via the support pin 6 is provided. The flange portion 6a of the support pin 6 abuts on the bottom surface of the shaft support portion 34b, and serves as a positioning surface of the bobbin 3 in the axial direction. Here, the “locking means” in the present invention includes the ratchet wheel 18, the engaging internal teeth 2, and the pawl 16 in the above embodiment.

A hanger member 37 is disposed on the left side of the gear case 34 in FIG. 3, and a sensor cover 35 is disposed outside the side plate 1a that covers the gear case 34. The rotation axis of the hanger member 37 coincides with the rotation axis of the bobbin 3 extending parallel to the adjustment axis 71 of the seat back 62. The vehicle body acceleration sensor 51 is provided in the storage portion 3 of the hanger member 37.
8 is detachably attached. The hanger member 37 has a tongue-like connecting portion 37b formed with a long hole 37a serving as a connecting portion with the adjusting means 39, and extends radially outward.

FIG. 4 shows a seat belt retractor 100.
FIG. As shown in FIG. 4, the sensor arm 53 of the vehicle body acceleration sensor 51 has a base end side shaft portion 53 a rotatably supported by the hanger member 37. The sensor arm 53 has a tip 5
A first position for actuating locking means for locking the rotation of the bobbin 3 in the webbing withdrawing direction by pushing up the lock arm 5 by 3b and engaging the lock arm 5 with the teeth 18b of the ratchet wheel 18; Thus, the lock arm 5 can be pivotally displaced about the shaft 53a as a rotation center to a second position where the lock arm 5 is disengaged from the teeth 18b and does not operate the lock means.

The outer peripheral surface 5a where the lock arm 5 contacts the sensor arm tip 53a is an arcuate surface, and the center of curvature of the outer peripheral surface 5a coincides with the centers of the bobbin 3 and the ratchet wheel 18. The radius of curvature R of the outer peripheral surface 5a is equal to the distance from the center of the bobbin 3 and the ratchet wheel 18 to the sensor arm tip 53b.
Therefore, the position of the outer peripheral surface 5a of the lock arm 5 is equal to the locus of the sensor arm tip 53b when the vehicle body acceleration sensor 51 is rotated around the bobbin 3 by the adjusting means 39 and adjusted to an appropriate position. Lock arm 5
Is attached to the side plate 1a of the retractor base 1 and does not move with the vehicle body acceleration sensor 51 as shown in FIG. 5 even if the seat back 62 is inclined. Then, the tip 53b of the sensor arm 53
Supports the outer peripheral surface 5a of the lock arm 5 having an arc surface having a radius of curvature R concentric with the center of the bobbin 3, so that the sensor can be used regardless of the rotational position of the vehicle body acceleration sensor 51. The lock arm 5 does not rotate around the pin 5b in the direction of the ratchet wheel 18 unless is operated.

The adjusting means 39 includes a rod member 81 for interlocking the hanger member 37 around the rotation axis only in a rotatable range thereof, and a guide cylinder 82 in which the rod member 81 is slidably accommodated. Prepare. As shown in FIG. 4, the retractor-side end of the guide tube 82 is positioned so that the retractor-side end of the rod member 81 passes around the connection portion 37 b of the hanger member 37. Side plate 1a
It is fixed to. The other end of the rod member 81 is connected to a mechanism for controlling the movement of the rod member 81, but is not directly related to the gist of the present invention, and a detailed description thereof will be omitted.

The retractor-side end of the rod member 81 is
A guide member 90 that is connected to the hanger member 37 via a pin 85 that engages with the elongated hole 37a of the connecting portion 37b, and that is attached to the retractor side end of the guide cylinder 82.
Is biased toward the other end by a compression coil spring mounted on the other end.

Next, the operation of the seat belt retractor will be described. When the webbing acceleration sensor or the vehicle body acceleration sensor 51 operates in an emergency such as a collision, the gear lock arm 26 or the sensor arm 5
The lock arm 5 receiving the force from the block 3 prevents the ratchet wheel 18 from rotating in the webbing withdrawing direction, and activates the locking means of the retractor.

After the rotation of the ratchet wheel 18 in the webbing pull-out direction is stopped, and the webbing is further pulled out from the retractor, the ratchet wheel 1
8 has a rotation delay with respect to the bobbin 3 and is relatively rotated in the webbing winding direction (the direction of the arrow X1), so that the cam hole 18a of the ratchet wheel 18 is
6b is moved radially outward from the rotation center axis of the bobbin 3. Then, the pawl 16 is pivotally rotated about the support shaft 7 in the direction of engagement with the engagement internal teeth 2 (the direction of arrow Y1 in FIG. 2). When the webbing is further pulled out from the retractor, the engagement teeth 16c of the pawl 16 mesh with the engagement internal teeth 2 to complete the lock.

At the time of this locking operation, the sensor arm 53
Does not directly mesh with the ratchet wheel, but acts on the lock arm 5 supported by the pin 5b on the side plate 1a.
It is designed to mesh with. Therefore, the rotation of the ratchet wheel 18 in the belt withdrawal direction can be stopped by the lock arm 5 only at the rotation angle interval of the jump which is the number of teeth. That is, the pole 16 is the base 1
The rotation of the ratchet wheel 18 is prevented by the lock arm 5 only at the jump position corresponding to the position where the engagement internal teeth 2 and the engagement internal teeth 2 mesh properly, so that locking is ensured. Therefore, even if the seat back 62 is tilted and the vehicle body acceleration sensor 51 is adjusted to an appropriate position, the position of the lock arm 5 for operating the locking means does not change, and a reliable locking operation can be guaranteed.

Next, a second embodiment of the present invention will be described.
As shown in FIG. 6, a vehicle body acceleration sensor 110, which is a sensing means of the seat belt retractor 200 according to the second embodiment, includes an inertial body 111 that detects the acceleration of the vehicle body,
A sensor case 112 on which the inertial body 111 is placed,
The lock arm 95 is connected to the teeth 18 b of the ratchet wheel 18.
A sensor arm 113 that pushes up to a lock position with
And a tongue-shaped connecting portion 114 having an elongated hole 114a serving as a connecting portion with the adjusting means 39.

The vehicle body acceleration sensor 110 is mounted around a center 111a of the inertial body 111 at a standby position. Further, on the lower surface of the lock arm 95, an outer peripheral surface 9 formed of an arc surface concaved downward is provided.
5a are formed. The center of curvature r of the outer peripheral surface 95a
Coincides with the center 111a of the inertial body 111. Also,
The radius of curvature r of the outer peripheral surface 95a is
0 from the center 111a of the inertia body 111 to the sensor arm 1
13 is equal to the distance to the tip 113b. That is, the position of the outer peripheral surface 95 of the lock arm 95 is determined by the inclination angle of the seat back 62 and the vehicle body acceleration sensor 11.
Sensor arm tip 1 when adjusting the position of 0
13b.

Since the lock arm 95 is attached to the side plate 1a of the retractor base 1, even if the seat back 62 is inclined, it does not move together with the vehicle body acceleration sensor 110 as shown in FIG. And
The tip 113b of the sensor arm 113 is connected to the inertial body 1
Since the outer peripheral surface 95a of the lock arm 95 having an arc surface having a radius of curvature r concentric with the center of the abutment 11 is abutted and supported, the sensor does not operate regardless of the rotational position of the vehicle body acceleration sensor 110. As long as the lock arm 95 does not rotate toward the ratchet wheel 18 around the pin 95b. Therefore, even if the seat back 62 is tilted and the vehicle body acceleration sensor 110 is adjusted to an appropriate position, the position of the lock arm 95 for operating the locking means does not change, and a reliable locking operation can be guaranteed.

The configurations of the locking means, the vehicle body acceleration sensor, and the like in the present invention are not limited to the above-described embodiment, but can be appropriately changed based on the gist of the present invention. For example, a configuration may be adopted in which an engaging tooth serving as a locking means is provided on a bobbin, and a lock member engaging with the engaging tooth is provided on a retractor base. Further, a configuration may be adopted in which a latch plate having engagement teeth on the outer periphery is used instead of the engagement internal teeth of the retractor base that constitutes the locking means.

[0030]

As described above, in the seat belt retractor of the present invention, the sensing means is supported so as to rotate about the winding shaft or the inertial body, and the lock arm contacts the sensing means. Since the surface is an arc surface having a radius of curvature of approximately the length from the center of the winding shaft or the center of inertia to the contact portion, the direction of the sensing means is adjusted, and the relative position with respect to the locking means changes. Also, the position of the lock arm supported in contact with the sensing means does not change, and the relative position between the lock arm and the lock means does not change. Therefore, even if the seatback is tilted and the sensing means is adjusted to a proper position, the position of the lock arm for operating the locking means does not change, and a reliable locking operation can be guaranteed.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a reclining type seat to which a seat belt retractor according to an embodiment of the present invention is attached.

FIG. 2 is a part of an exploded perspective view of the seat belt retractor shown in FIG.

FIG. 3 is an exploded perspective view of a remaining portion of the seat belt retractor shown in FIG. 2;

FIG. 4 is a partial sectional view of the seat belt retractor according to the first embodiment of the present invention.

5 is a partial cross-sectional view of the seat belt retractor shown in FIG. 4 in a state where the seat back is tilted rearward.

FIG. 6 is a partial sectional view of a seat belt retractor according to a second embodiment of the present invention.

7 is a partial cross-sectional view of the seat belt retractor shown in FIG. 6 in a state where the seat back is tilted rearward.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Retractor base 1a, 1b Side plate 2 Engagement internal teeth 3 Bobbin 4 Ring member 5, 95 Lock arm 5a, 95a Outer peripheral surface 15 Winding spring device 16 Pole 16c Engagement teeth 18 Ratchet wheel 18a Teeth 30 Inertia plate 37 Hanger member 39 Adjusting means 51 Body acceleration sensor 53, 113 Sensor arm 61 Reclining seat 62 Seat back 63 Seat seat 100 Retractor for seat belt 110 Body acceleration sensor 111 Inertial body 112 Sensor case 300 Retractor for seat belt

Claims (1)

[Claims] A locking means for locking rotation of the take-up shaft in a webbing pull-out direction; a lock arm rotatably attached to a retractor base for operating the locking means; The seat back includes a sensing unit that is freely attached and operates the lock arm by sensing a predetermined acceleration, and an adjusting unit that appropriately adjusts the orientation of the sensing unit according to a tilted state of the seat back. In the seat belt retractor incorporated, the sensing means is supported so as to rotate about the winding shaft, and a contact surface of the lock arm with the sensing means is in contact with the center of the winding shaft. A retractor for a seatbelt, characterized in that it is an arc surface having a length up to a portion having a substantially radius of curvature.