JPH0723322Y2 - Seat belt retractor - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a seat belt retractor, and in particular,
The present invention relates to an improvement of a seat belt retractor that does not give a feeling of pressure to a wearer when wearing a webbing.

[Prior art and its problems]

As a conventional seat belt retractor of this type, there is a seat belt retractor described in JP-B-61-22048. FIGS. 1 to 6 of this publication show a comparative example of the device of this publication. However, since the structure of this comparative example has a wasteful path and the movement is uncertain, The invention is directed to the webbing take-up rotation direction, which is urged in the webbing take-up direction and rotatably supported by the base, and which is integrally attached to the take-up shaft in the rotational direction. A ratchet wheel having an engaging surface, a cam plate rotatably provided in association with the winding shaft and the ratchet wheel by a frictional engagement action, and a webbing winding of the winding shaft engaged with the ratchet wheel. A ratchet provided to prevent rotation in the direction of the cam plate and biased toward the engagement position inward of the cam plate in the radial direction. A first guide path extending in a substantially circumferential direction that guides the ratchet from the engagement position to the non-engagement position with the ratchet wheel, and the ratchet in front of the engagement position while not engaging the ratchet wheel with the webbing winding. It is guided to the disengaged position and is folded back inward in the radial direction from the end of the first guide passage held therein, and extends in a substantially circumferential direction slightly beyond the start end of the first guide passage, whereby it is attached in the engagement position direction. The second guide path that automatically falls by the urging force when the biased ratchet reaches the end of the first guide path, and the second guide path that guides the ratchet held together with the webbing drawer to the engagement position. The second guide path extends to the first end of the first guide path.

However, in the device of this publication, when the ratchet engages with the ratchet wheel in a state where almost all of the webbing is pulled out, in order to release this engagement, a stroke for further withdrawing the webbing cannot be obtained. There is a problem that the engagement cannot be released, and when such a situation occurs, the webbing can no longer be wound and cannot be used.

[Purpose of device]

The present invention provides a seat belt retractor which overcomes the above-mentioned problems in the conventional art and disengages the ratchet from the ratchet wheel to retract the webbing when the webbing is pulled out. The purpose is to

[Outline of device]

The present invention relates to a ratchet wheel that rotates integrally with a take-up shaft of a webbing and that has a plurality of teeth formed on the outer periphery thereof, and a ratchet wheel that is movably disposed so as to engage with the teeth of the ratchet wheel. A ratchet that engages and restrains the rotation of the winding shaft in the winding direction,
A cam plate that is rotatable by frictional engagement with the take-up shaft and guides the ratchet; and a stopper that is rotatably supported by the take-up shaft and that holds the ratchet apart from the cam plate when the webbing is pulled out. The cam plate guides the ratchet from an engaged position to teeth of the ratchet wheel to a disengaged position, and a first guide path extending in a circumferential direction about a rotation axis of the cam plate, and (1) a second guide path that returns from the end of the first guide path to the inner diameter direction of the cam plate to hold the ratchet in a non-engagement position; and a second guide path that returns from the end of the second guide path to the inner diameter direction of the cam plate and 1 is provided with a third guide path that communicates with the start end of the guide path and guides the ratchet to the engagement position together with drawing out of the webbing,
The stopper is pushed by a protrusion provided on the cam plate to hold the ratchet at the end position of the first guide path of the cam plate and to rotate the cam plate in the pull-out direction when the webbing is pulled out. A state in which the ratchet is stopped and the ratchet is held by the stopper so that the cam plate is released and guided to the starting end of the second guide path after the cam plate has rotated a predetermined angle when winding the webbing. The rotation angle of the cam plate from the end of the second guide path to the rotation angle of the cam plate from the start end of the third guide path of the cam plate to the end of the first guide path are substantially equal. The ratchet wheel is retained by holding the ratchet in the disengaged position with respect to the ratchet wheel with the stopper. It is obtained by substantially equal to the rotation speed of the winding shaft for the ratchet engagement and disengagement with respect.

[Example of device]

 Hereinafter, the present invention will be described with reference to the embodiments shown in the drawings.

FIG. 1 is a schematic view of the entire seat belt retractor according to the present invention. The retractor body 1 has a bottom plate 2, and side plates 3 and 4 stand on both side edges of the bottom plate 2. The bottom plate 2 and the side plates 3 and 4 are U-shaped as a whole. The side plates 3 and 4 rotatably support a webbing take-up shaft 5 through which the side plates 3 and 4 are inserted. The take-up shaft 5 is located between the side plates 3 and 4. The drum 6 around which is wound is fitted. As an example, the end portion of the winding shaft 5 outside the one side plate 4 detects the acceleration of the vehicle, and when an acceleration equal to or higher than a set value acts on the vehicle, an emergency lock for restraining the occupant by restraining the withdrawal of the webbing. A mechanism is provided,
Since this emergency lock mechanism is publicly known, its illustration and detailed description are omitted.

At the end of the take-up shaft 5 outside the other side plate 3, there is formed a cut-off portion 5a that is close to the axial direction, and the take-up shaft 5 having the cut-off portion 5a is formed. An auxiliary shaft 7 is provided which is relatively tightly fitted to the end and rotates integrally with the winding shaft 5. As shown in detail in FIG. 2, a ratchet wheel 8 is integrally provided around the auxiliary shaft 7, and an outer periphery of the ratchet wheel 8 is engaged with a ratchet 10 described later in the webbing winding direction. Are formed with a plurality of teeth 9, 9 ... Which restrain the rotation of the winding shaft 5. The ratchet 10 is pivotally mounted on a cover 29, which will be described later, surrounding the outside of the side plate 3, so that the ratchet 10 has its engaging portions 11 on the teeth 9 of the ratchet wheel 8 by a wire spring 12. It is biased in the engaging direction.

A flange 13 is provided around the base end of the auxiliary shaft 7, and a cam plate 14 having a diameter larger than that of the ratchet wheel 8 is provided between the flange 13 and the ratchet wheel 8.
Is rotatably supported. The cam plate 14 is biased toward the ratchet wheel 8 by a disc spring 15 interposed between the cam plate 14 and the flange 13 and frictionally engages with the ratchet wheel 8.

Cam plate on the side facing the ratchet wheel 8
The surface of 14 is provided with a cam projection 16 that forms a circumferential cam. The cam projection 16 is formed with a recess 17 whose radius from the auxiliary shaft 7 is smaller than the radius of the ratchet wheel 8 and in which each tooth 9 of the ratchet wheel 8 projects outward. A spiral portion 18 is formed which is a part of the first guide path whose radius gradually increases in the clockwise direction over a range of about 280 degrees, and the spiral portion 18 has a diameter larger than the radius of the ratchet wheel 8 even at the minimum position of the radius. It is said that. The spiral portion 18 rotates the take-up shaft 5 and the drum 6 in the webbing pull-out direction from the state where the teeth 9 of the ratchet wheel 8 are engaged with the engaging portions 11 of the ratchet 10. To face. A step portion 19 extending inward in the radial direction is formed at a portion having a maximum radius which is an end portion of the spiral portion 18, and an inner diameter of the step portion 19 is continuous with the recess 17 and has an outer diameter thereof. An arc portion 20 serving as a third guide path having a diameter larger than the outer diameter of the ratchet wheel 8 is formed. Further, a guide wall 22 which is a circular arc concentric with the auxiliary shaft 7 is provided on the cam plate 14 so as to have a small gap 21 in the circumferential direction from the maximum radius portion of the spiral portion 18. The guide wall 22 has substantially the same height as the cam projection 16, has a relatively narrow width, and is formed over a range of approximately 160 degrees. The guide wall 22 also serves as a part of the first guide path and the second guide path.

As shown in detail in FIGS. 3A and 3B, a pair of protrusions 23, 24 are provided at the tip of the ratchet 10 at intervals in the width direction. The protrusion 24 is formed to be longer than the outer protrusion 24, and only the outer protrusion 24 can pass through the gap 21 between the spiral portion 18 and the guide wall 22. Further, when the inner protrusion 23 is in contact with the spiral portion 18, the arc portion 20, etc., the engagement portion 11 of the ratchet 10 cannot engage with the tooth 9 of the ratchet wheel 8. The engaging portion 11 of the ratchet 10 can be engaged with the tooth 9 of the ratchet wheel 8 only when the protrusion 23 of the ratchet 10 faces the recess 17. Further, the both projections 23, 24 are adapted to be laid across the guide wall 22.

A stopper 25 is independently rotatably disposed between the ratchet wheel 8 and the cam plate 14,
The stopper 25 has a protrusion 23 on the inner side of the ratchet 10.
Is formed on the outside of the spiral portion 18 and the circular arc portion 20, and at the end portion of the holding portion 26 in the counterclockwise direction, the projection 23 held by the holding portion 26 is prevented from falling off. A protrusion 27 for preventing is provided so as to protrude radially outward. Further, on the cam projection 16 near the end of the guide wall 22 opposite to the gap 21, a projection 28 for rotating the stopper 25 to release the holding of the ratchet 10 by the stopper 25. Is projected. When the stopper 25 releases the ratchet 10 by being rotated by the projection 28, the projections 23 and 24 of the ratchet 10 are positioned on the inner side and the outer side of the guide wall 22 so as to be straddled by the action of the wire spring 12. It is designed to be introduced at the beginning of the second guideway.

The outer periphery of the ratchet wheel 8, ratchet 10, cam plate 14, cam projection 16, guide wall 22, stopper 25, etc. is covered with a cover 29, and the auxiliary shaft 7
The end of the cover penetrates the cover 29. The outer end of the auxiliary shaft 7 of the cover 29 is covered with another cover 30, and the auxiliary shaft 7 is rotated in the webbing winding direction between the cover 30 and the auxiliary shaft 7. The spiral spring 31 that urges in this manner is interposed.

Next, the operation of the above-described embodiment will be described.

In the fully wound state of the webbing, as shown in FIG. 4H, the engaging portion 11 at the tip of the ratchet 10 is at the starting end of the third guide path, and the protrusion 23 inside the ratchet 10 causes the cam projection of the cam plate 14 to project. Since it is in contact with the circular arc portion 20 of the portion 16, the tooth 9 of the ratchet wheel 8 is disengaged.

When the webbing is pulled out for mounting from the above-mentioned completely wound state of the webbing, the webbing take-up shaft 5
The ratchet wheel 8 that rotates together with the ratchet wheel 8 rotates clockwise in FIG. 4H, and the cam plate 14 frictionally engaged with the ratchet wheel 8 also rotates in the same direction. Then, passing through the end of the third guideway, as shown in FIG. 4A,
The protrusion 23 inside the ratchet 10 faces the recess 17 of the cam protrusion 16, and the engaging portion 11 of the ratchet 10 engages with the ratchet wheel 8.
However, since the ratchet 10 does not restrain the rotation of the ratchet wheel 8 in the pulling-out direction of the webbing, the ratchet wheel 8 and the cam plate continue to contact.
14 rotates in the same direction, the ratchet 10 is guided to the first guide path, and as shown in FIG. 4B, the protrusion 23 on the inner side of the ratchet 10 is gradually swirled along the spiral portion 18 of the cam plate 14. Moves radially outward of the section. Then, when the tip portion of the ratchet 10 faces the gap 21 between the spiral portion 18 and the guide wall 22 as shown in FIG.
Since the protrusion 23 inside the ratchet 10 is longer than the length of the gap 21, it passes without being introduced into the gap 21, and when it continues to rotate in the same direction, as shown in FIG. The projection 23 is located at a position facing the end of the guide wall 22 (end of the first guide path). Then, the rotatable stopper 25 is pushed by the protrusion 28 protruding from the cam plate 14 rotating with the ratchet wheel 8 to hold the ratchet 10 at a position separated from the first guide path of the cam plate 14. . After that, when the ratchet wheel 8 is further rotated clockwise to pull out the webbing, the protrusion 23 of the ratchet 10 is engaged with the protrusion 27 of the stopper 25, and the stopper 25 is engaged with the protrusion 28 of the cam plate 14. Therefore, the cam plate 14 can no longer rotate in the clockwise direction, so that the cam plate 14 stops and only the ratchet wheel 8 slides against the cam plate 14 and continues to rotate. When the webbing of a predetermined length is pulled out in this manner, the tongue (not shown) at the tip of the webbing is attached to the buckle, and when the hand is released, the spiral spring 31
By this action, the ratchet wheel 8 rotates counterclockwise in order to wind up the extra webbing, and the cam plate 14 frictionally engaged with the ratchet wheel 8 also rotates counterclockwise. At this time, the ratchet 10 is held by the stopper 25. Then, when the ratchet wheel 8 and the cam plate 14 make about one rotation in the counterclockwise direction, as shown in FIG. 4E, the projection 28 of the cam plate 14 abuts on the stopper 25 holding the ratchet 10, As shown in Fig. 4F, push the stopper 25 counterclockwise to stop it.
Release holding of ratchet 10 by. Then, since the end portion of the guide wall 22 faces the vicinity of the protrusion 28, the ratchet 10 straddles the guide wall 22 so that both the protrusions 23 and 24 of the ratchet 10 are located inside and outside the guide wall 22. Sit down,
It is introduced at the beginning of the second guideway. Then, when the winding of the extra webbing is further continued, as shown in FIG. 4G,
The cam plate 14 continues to rotate in the same direction as the ratchet wheel 8 so that the projection 24 on the outer side of the ratchet 10 extends along the outer side of the guide wall 22, and the projection 24 causes the gap 21 between the spiral portion 18 and the guide wall 22. When it comes to the end of the second guide path opposite to, the protrusion 24 passes through the gap 21 and is guided to the start end of the third guide path by the action of the wire spring 12 that urges the ratchet 10 clockwise. 4. Take the position shown in FIG. From FIG. 4D to FIG. 4H, the cam plate 14 makes at least about 1.5 revolutions. After that, when the winding of the extra webbing is further continued, the ratchet 10 of the cam plate 14 is engaged with the step portion 19 of the cam plate 14 and cannot rotate counterclockwise. Therefore, only the ratchet wheel 8 slides on the cam plate 14. And continue to rotate counterclockwise. After the winding of the extra webbing is completed, the webbing is slightly pulled out by moving the body a little, and the ratchet wheel 8 together with the cam plate 14 moves about 0.25 clockwise from the state of FIG. When it rotates and goes past the end of the third guideway, the projection 23 of the ratchet 10 becomes
When the engaging portion 11 of the ratchet 10 engages with the tooth 9 of the ratchet wheel 8 facing the recess 17 of the, the webbing can no longer be wound. Therefore, the webbing is about 0.
Since it is installed with a margin of 25 rotations, it does not tightly restrain the occupant. When the occupant moves his / her body in the state of FIG. 4A, the ratchet wheel 8 rotates clockwise together with the cam plate 14, and the ratchet 10 slides on the first guide path. Approximately 1.25 turns from the stopper 25 to the ratchet 10 as shown in Fig. 4D.
4 until reaching the end position of the first guideway holding
In the states shown in B and C, the withdrawal length of the webbing is stored such that the occupant's posture always returns to the position shown in FIG. 4A.

As described above, after the occupant pulls out the webbing and engages the buckle, the cam plate 14 makes at least about 1.5 turns in the webbing winding direction to the state shown in FIG. 4H, and further makes about 0.25 turn in the webbing pulling direction. As a result, the ratchet 10 and the teeth 9 of the ratchet wheel 8 are brought into the engagement state shown in FIG. 4A. That is, after engaging the buckle, in the engaged state shown in FIG. 4A, the webbing is wound at least about 1.25 rotations in the winding direction. The webbing is pulled out from the state shown in FIG. 4A until the ratchet 10 is disengaged from the teeth 9 of the ratchet wheel 8 and the stopper 25 holds the ratchet 10 as shown in FIG. 4D. At least about 1.25 rotations are withdrawn. Ratchet 10 and ratchet wheel 8 like this
The minimum winding amount for engaging the tooth 9 of the above is substantially equal to the withdrawing amount for releasing the engagement and holding the ratchet 10 by the stopper 25.

When the webbing is pulled out to the state shown in FIG. 4D,
Since the ratchet 10 is held by the stopper 25 and the above-mentioned memory is erased, again from FIG. 4E to FIG. 4H.
Will be remembered again through the route to. In order to detach the tongue of the webbing from the buckle and completely wind the webbing, the tongue is detached from the buckle after pulling out the webbing until the state shown in FIG. 4D is erased. Then, due to the action of the spiral spring 31, FIG.
Then, the state shown in FIG. 4H is obtained through FIGS. 4F and G, and the webbing can be completely wound up.

As described above, according to the present embodiment, it is possible to remove the feeling of pressure when the seat belt is worn by incorporating the natural movement of the occupant wearing the seat belt. The webbing can be installed with a sufficient margin, and the webbing take-up amount for removing tension does not become larger than the webbing withdrawal amount for releasing, so the webbing withdrawal amount can be set at any time. However, the tension of the webbing can be removed and released, and there are no restrictions on use. Furthermore, the number of parts is small, the shapes of the cam plate 14 and other parts are simple, and there are few places causing failure, so that the operation is highly reliable.

In the embodiment described above, a solenoid is provided, and the plunger of the solenoid is directly or indirectly connected to the ratchet 10, and the disengagement of the buckle is detected to urge or deactivate the solenoid to engage the ratchet 10. 11
May be disengaged from the teeth 9 of the ratchet wheel 8.

[Effect of device]

As described above, according to the present invention, the winding amount of the webbing for actuating the pressure sensation prevention mechanism and the withdrawal amount of the webbing for releasing the mechanism are substantially equal to each other, so that the ratchet wheel can be used in any state of withdrawing the webbing. It is possible to release the engagement of the ratchet with respect to and to wind the webbing, thereby maintaining excellent operability.

[Brief description of drawings]

FIG. 1 is a schematic longitudinal sectional view showing an embodiment of a seat belt retractor according to the present invention, FIG. 2 is an enlarged front view showing a main part of FIG. 1, and FIGS. 3A and 3B are shown in FIG. FIG. 4 is an enlarged side view and bottom view of the ratchet, and FIGS. 4A, 4B, 4C, 4D, 4E, 4F, 4G, and 4H are explanatory views showing the action of the seat belt retractor of FIG. 1. 1 ... Retractor body, 5 ... Winding shaft, 8 ...
... ratchet wheel, 9 ... teeth, 10 ... ratchet,
11 ... Engaging part, 14 ... Cam plate, 16 ... Cam projection,
17 ... recess, 18 ... swirl, 19 ... step, 20 ... arc, 21 ... gap, 22 ... guide wall, 23,24,28 ... projection,
25 …… Stopper.

Claims (1)

[Scope of utility model registration request] 1. A ratchet wheel that rotates integrally with a webbing take-up shaft and has a plurality of teeth formed on its outer periphery,
A ratchet that is movably disposed so as to be able to engage with the teeth of the ratchet wheel and that engages with the teeth of the ratchet wheel to restrain the rotation of the winding shaft in the winding direction, and the winding shaft and the friction member. The cam plate, which is rotatable by coupling, guides the ratchet, and a stopper which is rotatably supported by the winding shaft and holds the ratchet apart from the cam plate when the webbing is pulled out. , Guiding the ratchet from the engagement position to the teeth of the ratchet wheel to the non-engagement position, and extending from the end of the first guide path to the first guide path extending in the circumferential direction around the rotation axis of the cam plate. A second guide path that folds back in the inner diameter direction of the cam plate to hold the ratchet at the non-engagement position, and the end of the second guide path is used to cover the ratchet. The stopper is provided on the cam plate so as to be folded back in the inner diameter direction of the plate and communicate with the starting end of the first guide path, and to lead the ratchet to the engagement position with the withdrawal of the webbing. When the webbing is pulled out, the ratchet is held at the end position of the first guide path of the cam plate and the rotation of the cam plate in the pulling-out direction is stopped, and the cam is pushed when the webbing is wound. After the plate rotates by a predetermined angle, the cam plate is released and guided to the start end of the second guide path, and the ratchet from the state where the ratchet is held by the stopper to the end of the second guide path. The rotation angle of the cam plate and the cam play from the start end of the third guide path of the cam plate to the end end of the first guide path. Almost retractor of the seat belt, characterized in that equal to the rotation angle of.