JPH0736850Y2 - Seat belt retractor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a seat belt retractor, and more particularly, when relative rotation occurs between a spindle and an inertia member attached to the spindle due to a difference in rotational speed. The present invention relates to a seat belt retractor that engages a pawl with a ratchet wheel attached to a spindle to prevent rotation of the spindle in a pull-out direction.

[Conventional technology]

The seat belt retractor is provided with a mechanism for preventing rotation of the spindle in the pull-out direction in order to protect an occupant when an abnormal impact such as a collision of an automobile is received.

Conventionally, as a retractor for this type of seat belt, the one disclosed in Japanese Patent Laid-Open No. 59-88165 has been provided. This includes a spindle rotatably supported by a frame and a webbing take-up force applied thereto, a ratchet wheel attached to the spindle, an inertia member relatively rotatably attached to the spindle, and internal teeth. A lock ring having a cam slot and rotatably attached to the spindle and biased by a spring so as to rotate in the winding direction, and the lock when a rotational speed difference occurs between the spindle and the inertia member. An engaging means for engaging the inner teeth of the ring to connect the lock ring and the spindle, and a pawl swingably supported on the frame having an engaging projection that is received in the cam slot of the lock ring. It was done.

When there is a difference in rotational speed between the spindle and the inertia member, the lock ring is connected to the spindle by the engagement means, and the pawl engagement protrusion slides in the cam slot of the lock ring to move the pawl. It swings and engages with the ratchet wheel to prevent rotation of the spindle in the pull-out direction.

[Problems to be solved by the device]

In the above-mentioned conventional example, since the spindle is formed by fitting the resin cylinder on the metal shaft core, the spindle is heavy and expensive.

Further, the spring that urges the lock ring to rotate in the webbing winding direction is difficult to assemble, which has been a problem in automatic assembly.

Further, although the pawl is supported by the support pin inserted into the side plate of the frame, a large load is applied when the pawl is engaged with the ratchet wheel, so the spindle and the support pin are connected to strengthen the pawl support portion. A special plate was needed to support the support pins with the side plates of the frame. Further, since a part called the plate is required and the plate must be connected to the spindle, there is a drawback that the retractor device becomes large in the axial direction of the spindle.

The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a seat belt retractor which is lightweight and inexpensive, has a small number of parts, and is easy to assemble. Is to provide.

[Means for Solving the Problems]

In order to achieve the above object, a seat belt retractor according to the present invention includes a synthetic resin spindle rotatably supported between opposing side plates of a frame having a substantially U-shaped cross section and a webbing retracting force. , A ratchet wheel integrally fitted to one end of the spindle protruding to the outside of the side plate, and a return spring integrally formed on the outer peripheral surface with internal teeth on the inner peripheral surface and engaging projections on the outer peripheral surface. A synthetic resin lock ring that is biased in the winding direction and is attached to the spindle so as to be rotatable relative to it, an inertia member that is attached to the spindle so that relative rotation is possible, and a bending of a spring that is slidably attached to the inertia member. A lock arm having an elongated hole for receiving the edge and attached to the spindle so as to be biased by the coil spring in a direction not engaging with the inner teeth of the lock ring; And a pawl that is rotatably supported by a support pin that is supported between a side plate of the frame and a support plate that is formed by bending the lower end of the side plate toward the ratchet wheel, and that engages with the ratchet wheel. The rotational speed difference between the inertia member and the inertia member causes the spring attached to the inertia member to rotate the lock arm, the lock ring engages with the lock arm and connects with the spindle, and the engagement protrusion of the lock ring pawls. The rotation of the pawl causes the pawl claws to engage with the ratchet wheel to prevent the spindle from rotating in the pull-out direction.

〔Example〕

 Examples will be described with reference to the drawings.

FIG. 1 is an exploded perspective view of a main part of a seat belt retractor according to the present invention, FIG. 2 is a longitudinal sectional view, and FIG. 3 is a side sectional view.

Reference numeral 10 denotes a frame, which is formed by a back plate 11 fixed to the vehicle body and a pair of side plates 12a and 12b erected from both side edges of the back plate 11 to have a substantially U-shaped cross section. In order to support the support pin 14 of the pawl 13 together with the side plate 12a, the side plate 12a has a lower end edge bent outward in an L-shaped cross section to form a support plate 15. A spindle 16 is rotatably supported on the central portions of the side plates 12a and 12b. A spiral spring 17 that is connected to one end of the spindle 16 and biases the spindle 16 in the webbing winding direction is provided outside the side plate 12b. Reference numeral 18 is a cover attached to the side plate 12b so as to cover the spiral spring 17. 12c
Is a hole provided at the upper end of the side plate 12a for fitting a protrusion 37a of a return spring 37 of the lock ring 34, which will be described later.

The entire spindle 16 is made of a synthetic resin material. On the outer circumference of the spindle 16 between the side plates 12a and 12b,
A winding drum 20 for winding the webbing 19 is attached.

At the other end of the spindle 16 protruding to the outside of the side plate 12a,
A ratchet wheel 21 is integrally fitted near the side plate 12a. The pawl 13 is rotatably pivotally mounted between the side plate 12a and the support plate 15 by a support pin 14 so as to be engaged with the ratchet wheel 21. Paul 13
Has a claw portion 13a that engages with the ratchet wheel 21 and a shoulder portion 13b that engages with a lock ring 34 described later.

On the outer spindle 16 of the ratchet wheel 21,
A disc-shaped step portion 22 is formed to project. This disc-shaped step
Two support protrusions 23, 2 are provided on the end face of 22 at a predetermined interval.
The projection 4 is provided, and a concave groove 26 for accommodating a part of the coil spring 25 is provided. A locking protrusion 27 for locking one end of the coil spring 25 is formed on the inner wall of the lower end of the groove 26.

28 is a lock arm having a triangular shape or a bow shape,
The support protrusion 23 is fitted into the through hole 29 formed in the central portion thereof, and the coil spring is attached to the locking protrusion 30 provided at the base end portion.
The other end of 25 is locked. The lock arm 28 is biased in the counterclockwise direction in FIG. 3 by the coil spring 25, and its tip end is in contact with the support projection 24a when not engaged. Further, the tip end portion of the lock arm 28 is provided with a claw portion 31 that engages with the internal teeth 35 of the lock ring 34, and an elongated hole 33 that receives the bent edge 32a of the C-shaped spring 32. In the coil spring 25, the claw portion 31 has the lock ring 34.
The lock arm 28 is biased in a direction in which the lock arm 28 is not engaged with the inner tooth 35 of the lock arm 28.

The lock ring 34 is made of synthetic resin, and is arranged on the outer spindle 16 of the ratchet wheel 21 so as to be rotatable relative to the spindle 16 coaxially therewith. The lock ring 34 has as many inner teeth 35 as the number of teeth of the ratchet wheel 21 on its inner peripheral surface.
Is provided. The outer peripheral surface of the lock ring 34 has an inward recess
36a forms an engaging projection 36 in which projecting end portions 36b and 36c are formed. The inward recess 36a is engaged with the claws 13a and the shoulders 13b of the pawl 13, and when the lock ring 34 is rotated, the claws 13a are caused by the projections 36b or the shoulders 13b.
Is pushed by the projecting end portion 36c, and the pawl 13 rotates. Further, on the outer peripheral surface of the lock ring 34, an arc-shaped return spring 37 that returns the lock ring 34 to its original position when the lock ring 34 rotates is integrally formed of the same synthetic resin as the lock ring 34. Further, the return spring 37 has a protrusion 37a provided at the tip thereof fitted into a hole 12c provided in the side plate 12a.

An inertial member 38 is arranged on the spindle 16 outside the lock ring 34 so as to be relatively rotatable coaxially with the spindle 16. An inertial ring 39 made of metal is fitted to the inertial member 38, and the weight of the inertial ring 39 causes the inertial member 38 to perform inertial movement. The inertia member 38 is provided with an annular groove 40 for accommodating the spring 32, and the bent edge 32a of the spring 32 is also provided.
An annular hole 41 is provided in order to allow the insertion spring 32 to slide. Further, external teeth 44 that engage with the operating claws 43 of the vehicle sensor 42 are provided on the outer peripheral surface of the annular member 38.

The vehicle sensor 42 has a swingable receiving body 47, which receives a spherical weight 46 provided on the actuating claw 43, in a frame body 45 thereof. When the entire retractor device receives an impact, the receiving body 47
Oscillates and the weight 46 causes the operating claw 43 to float, and the operating claw 43 engages with the outer teeth 44 of the inertia member 38.

Reference numeral 48 denotes a cover attached to the side plate 12a, and various members such as the ratchet wheel 21 located outside the side plate 12a are covered with the cover 48. The cover 48 is provided with a storage portion 48a for storing the return spring 37 of the lock ring 34.

[Action]

When an abnormal impact such as a car collision occurs, a sudden pulling force is generated on the webbing 19 that restrains the occupant, and the spindle
16 rotates in the pull-out direction (counterclockwise in Fig. 3).

The inertia member 38 also rotates in the pull-out direction as the spindle 16 rotates, but the inertia member 38 has a rotational speed difference between the inertia member 38 and the spindle 16 due to the weight of the inertia ring 39, and the inertia member 38 is wound relative to the spindle 16. The relationship is such that it rotates in the direction (clockwise in FIG. 3). Due to the relative rotation of the inertial member 38 in the winding direction, the bent edge 32a of the spring 32 attached to the annular groove 40 of the inertial member 38 moves in the elongated hole 33 of the lock arm 28. Then, the lock arm 28 rotates in the same direction as the inertia member 38 against the coil spring 25, and the claw portion 31 thereof meshes with the internal teeth 35 of the lock ring 34. This state is the state shown in FIG.

Next, since the lock ring 34 is in a state of being connected to the spindle 16 via the lock arm 28, the rotation of the spindle 16 is transmitted to the lock ring 34 via the lock arm 28, and the lock ring 34 resists the return spring 37. Then, it rotates in the pull-out direction (counterclockwise direction in FIG. 4). When the lock ring 34 rotates, the pawl 1 located in the inward recess 36a of the engaging protrusion 36
The pawl 13 of the pawl 13 is rotated clockwise as shown in FIG.
13a meshes with the ratchet wheel 21. Thus, rotation of the spindle 16 in the pull-out direction can be prevented.

The rotation of the spindle 16 in the pull-out direction stops, and the webbing 19
When the pulling force applied to the lock ring 34 disappears, the lock ring 34 rotates clockwise in FIG. 5 due to the return force of the return spring 37. Then, the other tip end 36c of the lock ring 34 pushes the shoulder portion 13b of the pawl 13, the pawl 13 rotates counterclockwise, and the pawl portion 13a of the pawl 13 does not mesh with the ratchet wheel 21. Further, the lock arm 28 is returned to its original position by the coil spring 25, and its claw portion 31 and the inner teeth of the lock ring 34.
No longer meshes with 35.

When the entire retractor device receives an impact, as shown in FIG. 6, the receiving body 47 of the vehicle sensor 42 swings and the weight 46 causes the operating pawl 43 to float, and the operating pawl 43 and the inertia member
The outer teeth 44 of 38 mesh. Then, as described above, the claw portions 31 of the lock arm 28 and the inner teeth 35 of the lock ring 34 mesh with each other, and the claw portions 13a of the pawl 13 and the ratchet wheel 21 mesh with each other.

[Effect of device]

Since the present invention is configured as described above and the entire spindle is made of synthetic resin, the device can be provided in a lightweight and inexpensive manner.

Further, since the support plate of the pawl is integrally formed with the side plate of the frame and the lock ring and its return spring are integrally formed, the assembly is easy.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a main part of a seat belt retractor according to the present invention, FIG. 2 is a longitudinal sectional view, FIG. 3 is a side sectional view, and FIGS. 4 to 6 are side sectional views showing an actuating mechanism. Is. 10 …… frame, 12a, 12b …… side plate, 13 …… pawl, 13a
...... Claw part, 13b ...... Shoulder part, 15 ...... Support plate, 16 ...... Spindle, 19 ...... Webbing, 21 ...... Ratchet wheel,
25 …… Coil spring, 28 …… Lock arm, 32 …… Spring,
32a: bent edge, 33: long hole, 34: lock ring, 35
...... Internal teeth, 36 ...... Engagement protrusion, 37 ...... Return spring, 38 ...... Inertial member.

Claims (1)

[Scope of utility model registration request] 1. A synthetic resin spindle rotatably supported between opposing side plates of a frame having a substantially U-shaped cross section and having a webbing take-up force applied thereto, and one end of the spindle protruding outside the side plate. , A ratchet wheel integrally fitted to the inner peripheral surface of the ratchet wheel, and internal teeth on the inner peripheral surface and engaging protrusions on the outer peripheral surface. A lock ring made of synthetic resin that can be attached, an inertia member that is relatively rotatably attached to the spindle, and an elongated hole that receives the bent edge of the spring that is slidably attached to this inertia member. The lock arm attached to the spindle so as to be biased in the direction not engaging with the inner teeth of the ring, the side plate of the frame and the lower edge of this side plate are bent to the ratchet wheel side. A support plate rotatably supported between the support plate and a pawl that engages with the ratchet wheel, and the inertia member is caused by a difference in rotational speed between the spindle and the inertia member. Rotating the lock arm by the attached spring, the lock ring engages with the lock arm and connects with the spindle, the engaging protrusion of the lock ring rotates the pawl, and the pawl part of the pawl engages the ratchet wheel. The seat belt retractor is characterized in that the rotation of the spindle in the pulling-out direction is prevented.