JPH0415558Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention detects the seatbelt withdrawal speed, and when this exceeds a predetermined speed, automatically prevents the rotation of the seatbelt take-up shaft. The present invention relates to a seat belt retractor that prevents seat belt extension.

(Prior Art) Among the seat belt retracting devices installed in vehicles such as automobiles, webbings are used to detect the speed at which the seat belt is pulled out due to the movement of the occupant's upper body, as well as vehicle sensors that detect impacts applied to the vehicle body. The seatbelt retractor is equipped with a sensor and uses both sensors to prevent the rotation of the seatbelt retractor shaft in the event of an emergency such as a vehicle collision, thereby preventing the seatbelt from extending. , which is particularly superior in terms of safety, and is expected to become more popular and demand to increase in the future.

By the way, this type of seatbelt retractor equipped with a webbing sensor for detecting the seatbelt withdrawal speed is shown in FIGS. 4 and 5, for example.
The configuration shown in the figure is common.

That is, in this winding device, a ratchet wheel 3 is fixed to one end of a winding shaft 2 rotatably supported by a frame member 1, and a metal flywheel 4 is attached adjacent to the ratchet wheel 3. An inertial member 6 formed by fitting a synthetic resin ring member 5 with external teeth that engages with an operating claw of a vehicle sensor on its outer periphery is rotatably supported, and the inertial member 6 and the ratchet wheel 3 are connected to each other. When the flywheel 4 causes a rotation delay with respect to the take-up shaft 2 due to inertia in the direction in which the seat belt 7 is pulled out, the pawl 8 pivoted to the frame 1 is moved around the outer periphery of the ratchet wheel 3 due to the phase shift. It has a structure in which a clutch-type interlocking mechanism 10 is interposed to engage with the engaging teeth 9 of.

Therefore, in the seat belt retractor having the above structure, the inertia member 6 is suddenly pulled out when the seat belt 7 is pulled out.
When there is a rotation delay due to inertia with respect to the take-up shaft 2, the inertia member 6 forcibly rotates the pawl 8 via the interlocking mechanism 10, engages the ratchet wheel 3, and extends the seat belt 7. It's becoming like that. (For example, see Japanese Patent Application Laid-Open No. 59-88165.) (Problems to be Solved by the Invention) However, in such a conventional seat belt retractor, the inertial member 6 is connected to the retractor shaft 2.
A metal flywheel 4 rotatably supported through a center hole 11 inserted into the shaft end of the flywheel 4, and a synthetic resin ring member with external teeth 12 fitted to the outer periphery of the flywheel 4 so as to be relatively rotatable. 5 and a C-ring-shaped linear spring 13 for rotating both with the required frictional force, it is necessary to manufacture and assemble these three components. Since it is necessary to fit the ring member 5 on the outer periphery of the wheel so that the wheel can rotate relative to each other, high machining accuracy is required on the outer periphery, which poses a problem of increasing manufacturing costs.

The present invention was devised by focusing on the problems that such conventional seat belt retractors had. By resiliently installing a spring member that operates the interlocking mechanism, the number of parts and the number of assembly steps are reduced, thereby solving the above-mentioned problems.

(Means for Solving the Problems) The configuration of the present invention for achieving the above object will be explained with reference to FIGS. 1 and 3, which correspond to embodiments.

The seat belt retractor of the present invention includes a frame member 21 fixed to a vehicle body, etc., and a frame member 21 fixed to a vehicle body etc.
1, the winding shaft 24 is rotatably supported by the winding shaft 24, and one end of the seat belt 27 is fixed to the outer periphery of the winding shaft 24, and the winding shaft 24 is always urged to rotate in the seat belt winding direction; a ratchet wheel 30 having a large number of engagement teeth 31 on its outer periphery; an inertia member 46 disposed coaxially adjacent to the ratchet wheel 30 and rotatably supported by the winding shaft 24; It is pivotally connected to the frame member 21 near the outer periphery of the ratchet wheel 30,
A pawl 32 that can be fitted into and removed from the engagement teeth 31 of the ratchet wheel 30 is provided between the pawl 32 and the inertia member 46, and the inertia member 46 is connected to the take-up shaft 24 to pull out the seat belt. When a rotation delay occurs in the direction, the pawl 32
A clutch-type interlocking mechanism that engages the engaging teeth 31 of the ratchet wheel 30 is provided.

In addition, the inertia member 46 has a support portion 48 and an outer peripheral portion 49 formed by the winding shaft 24 continuously and integrally formed of a synthetic resin material, and a spring member 50 made of linear spring steel is relatively rotatable thereto. The spring member 50 is connected to the input portion of the clutch-type interlocking mechanism.

(Function) In the seatbelt retractor of the present invention having the above configuration, since the inertia member 46 made of synthetic resin is linked to the clutch type interlocking mechanism via the spring member 50, the seatbelt 27 can be pulled out when the seatbelt 27 is pulled out. When the inertia member 46 lags behind the take-up shaft 24 in its rotation in the belt pulling-out direction due to a sudden increase in speed, the clutch-type interlocking mechanism is actuated via the spring member 50 that is frictionally fitted to the inertia member 46. Then, the pawl 32 is engaged with the ratchet wheel 30 to prevent the rotation of the take-up shaft 24, thereby preventing the seat belt 27 from extending later and maintaining the occupant in a restrained state.

(Example) Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

Fig. 1 is a front sectional view showing an embodiment of the seat belt retractor of the present invention, Fig. 2 is a side sectional view of the same retractor, and Fig. 3 is an inertia applicable to the seat belt retractor of the present invention. It is a perspective view showing an example of a member.

In these figures, 21 is a frame member formed by bending a thick metal plate into a U-shaped cross section, 22 and 23 are side walls that stand up approximately at right angles from the bottom surface of the frame member 21, and 24 is a frame member that is perforated in the side walls 22 and 23. The seatbelt take-up shaft 24 is inserted into the shaft through holes 25 and 26 and rotatably supported, and the take-up shaft 24 is provided with a seatbelt 27 in a portion extending between the side walls 22 and 23. A winding spring whose rear end is fixed and wound in multiple layers, and whose outer end is fixed to a cover member 28 attached to the outer surface of the side wall 23 at an end 24a protruding outward from the side wall 23. The inner end of the seat belt 29 is fixed, and the winding spring 29 is always biased to rotate the seat belt 27 in the winding direction, that is, in the direction of arrow Y in FIG.

Further, the seat belt take-up shaft 24 is
An end portion 24b projecting outward from the side wall 22 is integrally provided with a ratchet wheel 30 having a large number of engagement teeth 31 on its outer periphery.

Reference numeral 32 denotes a pawl rotatably supported by a support shaft 33 protruding from the outer surface of the frame side wall 22 near the outer periphery of the ratchet wheel 30. A pin 34 is provided on a lock ring 35 that is rotatable coaxially with the winding shaft 24 and that faces the engaging teeth 31 of the etching wheel 30 so as to be able to engage with it and protrudes outward from the side surface. It is inserted into a substantially S-shaped cam slit 36.

The lock ring 35 has internal teeth 37 on the inner peripheral surface of a cylindrical clutch case 35a protruding from its outer surface, the engagement direction of which is opposite to that of the ratchet wheel 30, and a spring with a constant biasing force. (not shown) rotates in the same direction as the take-up shaft 24 (direction of arrow Y in FIG. 2).

Further, at the end portion 24b of the winding shaft 24 at a position facing the internal teeth 37 of the locking ring 35, a fulcrum pin 39 is provided which projects from a retainer 38 that rotates together with the winding shaft 24, so that it can be pivoted. A claw portion 41 on the outer periphery of the carrier 40 supported by the lock ring 35 faces the inner teeth 37 of the lock ring 35 so as to be engageable, and a spring receiver 42 on the retainer 38 side and a spring receiver 44 on the carrier 40 side are provided. A compression spring 45 is provided which biases the claw portion 41 with a weak force in a direction to move the claw portion 41 away from the internal teeth 37.

46 is a center hole 4 in the circular stepped portion of the retainer 38.
It is an inertial member which is a main part of the present invention and is supported so as to be rotatable relative to the winding shaft 24 by a cap 47 fitted with the winding shaft 24 and fixed to the outermost end of the winding shaft 24. The inertia member 46 is connected to the center hole 4
6a is bored in the support portion 48 and the outer peripheral boss portion 4
9 is integrally formed of a synthetic resin material such as polyacetal or polyester having a relatively large specific gravity, and a spring made of linear spring steel bent into a substantially C shape is provided on the inner peripheral surface of the outer peripheral boss portion 49. The member 50 is friction-fitted, and one of U-shaped bent parts 51a, 51b, and 51c formed at both ends and the center of the spring member 50 is a projection protruding from the outer surface of the carrier 40. 52.

In the figure, 53 is the outer peripheral boss portion 4 of the inertial member 46.
Spring member 5 protruding from the inner surface of 9 at multiple locations
A rib-like projection 54 for preventing the zero from coming off is an external tooth formed on the outer periphery of the inertial member 46 so as to be able to engage with an operating claw 56 of a vehicle sensor 55 attached to the side wall 22 of the frame member 21. , 57
is from the ratchet wheel 30 to the cap 47.
A cover member 58 that surrounds each member leading to the frame member 21 and is fixed to the frame member 21 indicates a tie plate for maintaining the distance between the winding shaft 24 and the support shaft 23, respectively.

The seatbelt retractor of the present invention has the above-mentioned configuration. Next, its operation will be explained. First, when assembling the inertial member 46 to the retractor, the spring member 50 is compressed in advance. The inertia member 46 is inserted into the concave side of the inertia member 46, and the external force is removed and the inertia member 46 is brought into contact with the inner diameter surface. At this time, the spring member 50 is frictionally fitted to the inner surface of the outer circumferential boss portion 49 of the inertial member 46 due to the outward restoring force, and is prevented from coming off laterally due to the presence of the rib-like protrusion 53.

Thereafter, the center hole 46a of the inertial member 46 is rotatably inserted into the end portion 24b of the winding shaft 24, and the bent portions 51a, 51b, 51 of the spring member 50 are inserted.
c is engaged with the protrusion 52 of the carrier 40 constituting the clutch type interlocking mechanism, and the winding shaft 24
The cap 47 may be fixed to the cap 47 to prevent it from coming off.

In the seat belt retractor assembled in this manner, due to a rapid increase in the retracting speed of the seat belt 27, the rotation of the inertial member 46 in the seat belt retracting direction (arrow X direction) relative to the retracting shaft 24 is delayed. When a phase shift occurs with respect to the shaft 24 in the direction of the arrow Y in FIG. The carrier 40 is rotated in the same direction against the urging force of the compression spring 46, and the claw portion 41 of the carrier 40 is
is engaged with the internal teeth 37 of the lock ring 35. Therefore, the pull-out force of the seat belt 27 in the direction of the arrow X acting on the take-up shaft 24 at this time is:
A retainer 38 that rotates together with the take-up shaft 24
is transmitted to the lock ring 35 via the fulcrum pin 39 and carrier 40, the lock ring 35 rotates in the same direction (arrow X direction), and the cam slit 3
Arrow B indicates the pawl 32 in which the pin 34 is engaged in 6.
The claw portion 32a at the tip thereof engages with the engagement tooth 31 of the ratchet wheel 30 to prevent rotation of the winding shaft 24 in the direction in which the belt extends.

Furthermore, when the vehicle sensor 55 is activated due to sudden acceleration or deceleration of the vehicle and the actuating pawl 56 engages with the external teeth 54 on the outer periphery of the inertial member 46, the rotation of the inertial member 46 is blocked, so that the occupant's body When the pull-out force in the direction of arrow X is applied to the seat belt 27 due to the inertial force acting on the The rotational force is applied, and the pawl 32 rotates in the direction of arrow B, thereby blocking the rotation of the winding shaft 24.

(Effects of the invention) As described above, in the seatbelt retractor of the present invention, the entire inertial member for detecting the seatbelt withdrawal speed is made of a synthetic resin material that is easy to mold, and the interlocking mechanism is actuated by this inertial member. By friction-fitting a roughly C-shaped spring member, the metal flywheel used in conventional take-up devices is eliminated and the number of component parts of the webbing sensor is reduced, making it easier to manufacture inertial members. Moreover, assembly is extremely easy, and an excellent effect is exhibited in suppressing the rise in manufacturing costs of the seat belt retractor.

Moreover, according to the present invention, since the entire inertial member of the webbing sensor is made of synthetic resin material, there is little generation of abnormal vibration noise when the vehicle is running, and even when a vehicle sensor is installed.
It is easy to integrally form the external teeth on the outer periphery of the inertial member, and it is also possible to expect the effect that the ring gear will not come off unexpectedly from the flywheel, unlike when the flywheel and ring gear are formed separately and assembled.

[Brief explanation of drawings]

Fig. 1 is a front sectional view showing an embodiment of the seat belt retractor of the present invention, Fig. 2 is a side sectional view of the same retractor, and Fig. 3 is a view applicable to the seat belt retractor of the present invention. FIG. 4 is a front sectional view of a seatbelt retractor equipped with a conventional inertial member, and FIG. 5 is an exploded perspective view showing the configuration of the conventional inertial member. 21... Frame member, 24... Winding shaft, 27... Seat belt, 30... Ratchet wheel, 31... Engaging tooth, 32... Pawl, 3
5, 38, 40...clutch type interlocking mechanism, 46...
...Inertia member, 48...Supporting part, 49...Outer peripheral part (outer peripheral boss part), 50...Spring member, 5
4...External tooth, 55...Vehicle sensor, 56...
Working claw.

Claims (1)

[Scope of utility model registration request] a take-up shaft supported by a frame member and to which a belt winding force is applied; an inertia member having ratchet teeth on its outer peripheral surface and supported so as to be movable relative to the take-up shaft; an acceleration sensor that engages with ratchet teeth of the inertial member to apply resistance to rotation of the inertial member in the event of a vehicle emergency; The sensor is connected between an inertial member and the take-up shaft, and when a difference in rotational speed occurs between the take-up shaft and the inertial member due to the operation of the sensor, the sensor engages with the internal teeth of the lock ring and locks the lock ring. a carrier that connects the take-up shaft; and when the lock ring and the take-up shaft are connected by the carrier, the lock ring rotates in response to the rotation of the take-up shaft in the belt drawing direction, and the belt drawer of the take-up shaft is rotated. In a seat belt retractor equipped with a locking means for locking rotation, a supporting portion of the inertial member to the retracting shaft and an outer peripheral portion thereof are integrally formed of a synthetic resin material, and the inertial member is made of linear spring steel. A seat belt retractor characterized in that a spring member is frictionally fitted so as to be relatively rotatable, and a connecting portion to the carrier is engaged and connected to a bent portion of the spring member.