JPS625816B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a frame, a reel rotatably supported on the frame via a reel shaft, a seatbelt fixed to the reel so as to be retractable, and a seatbelt that is fixed to the reel in a winding direction. This invention relates to an emergency locking type seat belt retractor comprising a biasing spring and a locking device that locks the reel in an emergency.

This type of seatbelt retractor is known, for example, from Japanese Patent Laid-Open No. 48-9439. In this case, the rotation of the reel shaft causes the support disc, its pawl,
The force is transmitted to the pawl via the arms and protrusions of the inertia disk, which places a large load on the inertia disk. Furthermore, since a ratchet wheel is attached to the inertia disk, in order to perform locking in an emergency, the claw of the inertia sensing device must be engaged with the ratchet wheel attached to the inertia disk. The disk must move axially. Therefore, the axial movement of the inertia disk, and thus the locking operation, are not smooth and cannot be locked reliably.

The aim of the invention is to provide a retractor that does not have the above-mentioned drawbacks.

This problem is solved by a locking device that includes a first ratchet that is fixed to a frame and has first ratchet teeth in the axial direction of the reel, and a flange that is fitted and fixed to the reel shaft and has a protrusion that projects outward in the axial direction. and a second ratchet tooth facing the first ratchet tooth, the second ratchet tooth being guided by a hole that fits into the protrusion of the flange so that the flange cannot rotate relative to each other and can move in the axial direction.
a cam wheel having a first cam on an end surface opposite to the ratchet teeth; a spring separating the flange and the cam wheel from each other; and a second cam on one end surface engaging the first cam of the cam wheel. Equipped with
an inertia wheel loosely fitted onto the reel shaft and held so as not to move outward in the axial direction; a ratchet wheel attached to the inertia wheel and provided with third ratchet teeth; and a ratchet wheel capable of meshing with the third ratchet teeth. This problem is solved by comprising an inertial sensing device equipped with an engaging piece.

With this configuration, especially when locking the reel shaft, the locking force is transferred to the first ratchet, cam wheel,
Since it can be transmitted to the frame only through the flange, no locking force is transmitted to the inertia wheel that operates the cam wheel, so the load on the inertia wheel is small and its function remains constant even after long-term use. . Furthermore, since the inertia wheel does not move in the axial direction, the ratchet wheel attached to the inertia wheel and the engagement piece of the inertia sensing device can operate reliably and smoothly.

Next, the present invention will be explained in detail with reference to drawings showing embodiments.

As shown in FIGS. 1, 2 and 3, the emergency locking type seat belt retractor according to the present invention comprises a frame 1 having a U-shaped cross section, and the side plates 1A and 1B of the frame have concentric holes. 1A and 1b are open. A reel 2 is rotatably supported through the reel shaft 3 in the holes 1a and 1b of the side plates 1A and 1B. Therefore, the reel 2 and the reel shaft 3 are rotatably supported by the frame 1. The seat belt 6 is fixed to the reel shaft 3. A spring is provided at one end of the reel shaft 3 and biased in a direction to wind up the seat belt 6, and the spring is housed in the case 5. The cover 5 is fixed to one side plate 1B of the frame 1.

On the outside of the other side plate 1A of the frame 1,
A ring-shaped first ratchet 7 is fixed concentrically to the hole 1a. The center hole 7b of the first ratchet 7 is at least larger than the diameter of the reel shaft 3. The first ratchet 7 and the side plate 1A are fixed by the side plate 1A.
The hole 1D is provided around the hole 1a of the hole 1D.
It is preferable to fit and weld a pin (not shown) formed on the end face of the first ratchet 7 made of, for example, thermoplastic plastic in accordance with D, but other well-known means, such as gluing or spring fastening, may also be used. good. Near the outer periphery of the outer end surface of the first ratchet 7, first ratchet teeth 7A are provided that project outward in the axial direction. The first ratchet teeth 7A are formed in a sawtooth shape having an angle at least perpendicular to the direction in which the reel shaft 3 is rewound.

Frame 1 on the first ratchet 7 side of reel shaft 3
A flange 3B of the shaft pin 3E protruding from the shaft pin 3E is fitted into a notch 3C formed in the shaft pin 3E in a mutually complementary manner, so that the flange 3B rotates together with the reel shaft 3. A protrusion 3D that protrudes outward in the axial direction is provided near the outer edge of the flange 3B.

A cam wheel 8 is loosely fitted to the shaft pin 3E on the protrusion 3D side of the flange 3B. Flange 3
A spring 14 is provided between the flange 3B and the cam wheel 8, and biases the flange 3B and the cam wheel 8 in a direction to separate them. The cam wheel 8 is provided with second ratchet teeth on the end face on the flange 3B side, that is, on the first ratchet 7 side, which can mesh with the first ratchet teeth 7A. Cam wheel 8 also has flange 3
It has a hole 8D that fits into the axial projection 3D of B. Therefore, the cam wheel 8 has the protrusion 3D and the hole 8D.
Although it rotates together with the flange 3B due to the action of , it is slidable in the axial direction due to the action of an inertia wheel 11 which will be described later. A cam 8C is provided on the axially outer end surface of the cam wheel 8. A cam 11B of an inertia wheel 11, which is loosely fitted to the shaft pin 3E, is in contact with the cam 8C. A ratchet wheel 9 is loosely fitted around the outer periphery of the inertial wheel 11, so that the inertial wheel 11 and the ratchet wheel 9 can be mutually displaced in the rotational direction.
The displacement position is regulated by a recess 11A provided on the axially outer side of the inertia wheel 11 and a projection 9B provided on the radially inner side of the ratchet wheel 9. In this case, the inertia wheel 11 and the ratchet wheel 9 are connected by a connecting spring 10,
Normally, it moves by following the movement of the inertial wheel 11.

At the outermost end of the shaft pin 3E of the reel shaft 3, the inertia wheel 11 is prevented from falling outward by a snap spring 15 that engages with a circumferential groove 3G provided in the shaft pin 3E. The outer periphery of the inertial wheel 11 is provided with third ratchet teeth 9A that engage with pawls 13F of an inertial sensing device 13, which will be described later. an inertial body provided on the bottom plate 13B of the casing 13A of the inertial sensing device 13;
That is, the ball 13D is freely placed on the seat 13C of the ball 13D. One lever always in contact with the lower side of the ball 13D and the third ratchet tooth 9A
A double-armed lever consisting of one lever and the other lever formed as a claw 13F that can be engaged with the other lever is pivotally attached to the case 13A. This inertia sensitive device 13 is activated by the inertia of the ball, that is, in an emergency such as when a car collides, the ball 13D falls off from the ball seat 13C, pushes down the lever 13H and pushes up the pawl 13F, and the third ratchet tooth 9A is activated. to engage. In the inertial sensing device 13, on the one hand, when the bottom plate 13B is located on a plane perpendicular to the vertical direction, and when the ball 13D is located on the ball seat 13C, the pawl 13F does not engage with the third ratchet tooth 9A, and on the other hand, the ball 1
When 3D is detached from ball seat 13C, claw 1
3F is fixed to the frame 1 in a position where it meshes with the third ratchet tooth 9A. The emergency lock type seat belt retractor according to the present invention functions as follows.

(1) Normal time (a) The seat belt 6 can be wound onto the reel 2 and rewound by the action of the take-up spring. The reel 2 rotates in response to the motion of the seat belt being wound onto or unwound from the reel 2. As the reel 2 rotates, the reel shaft 3 also rotates accordingly. The rotation of the reel shaft 3 is directly transmitted to the cam wheel 8 via the flange 3B, and the rotation of the cam wheel 8 is transmitted from the first cam 8C of the cam wheel 8 to the second cam 11B of the inertia wheel 11.
B. The cam wheel 8, the inertia wheel 11 and the ratchet wheel 9 rotate together with the reel shaft 3.

(b) The unwinding speed of the safety belt 6 is 0.7G to the vehicle.
When the inertia wheel 11 is pulled out at the same speed as when the above acceleration/deceleration occurs, displacement occurs between the inertia wheel 11 and the cam wheel 8 in the rotational direction due to the inertia of the inertia wheel 11, and the inertia wheel 11
The second cam 11B pushes the first cam 8C of the cam wheel 8 inward against the force of the spring 14, and the second cam 11B of the cam wheel 8 pushes the first cam 8C inward against the force of the spring 14.
the first ratchet tooth 7A of the first ratchet 7
The rotation of the reel shaft 3 is controlled by the flange 3.
B. It is locked to the frame 1 via the cam wheel 8 and the first ratchet 7.

(2) In case of emergency (a) When acceleration/deceleration of approximately 0.3 to 0.7G is applied,
Ball 13D of inertial sensing device 13 is case 1
It fell off from the seat 13C provided at 3A, and the claw 13F
is pushed up and meshes with the third ratchet tooth 9A of the ratchet wheel 9. At this time, since the belt 6 is also being rewound, the flange 3B and the cam wheel 8 rotate together with the reel shaft 3, while the inertia wheel 11 is restrained by the inertia sensing device 13, so the inertia wheel 11
The second cam 11B pushes the first cam 8C of the cam wheel 8 inward in the axial direction against the action of the spring 14, and pushes the second ratchet tooth 8B of the cam wheel 8 into the first ratchet tooth 7 of the first ratchet.
A, and the reel shaft 3 is restrained to the first ratchet 7 via the flange 3B and the cam wheel 8. The belt is therefore locked against further unwinding. In addition, nail 13
The inertia wheel 11 rotates slightly until the reel shaft 3 is locked after the ratchet tooth 9A is locked by meshing with the ratchet tooth 9A. Since the rotational deviation between the ratchet teeth 9A and the pawl 13F is absorbed by the spring 10, only the spring force of the spring 10 acts between the ratchet tooth 9A and the pawl 13F.
No load occurs that would damage 3F or ratchet tooth 9A.

(b) When an acceleration/deceleration of 0.7G or more is applied, when the unwinding action of the belt 6 is transmitted to the cam wheel 8 via the reel shaft 3, the cam is The second ratchet 8B of the wheel 8 meshes with the first ratchet tooth 7A of the first ratchet 7, and at the same time, the unwinding movement of the reel shaft 3 is restrained. In this case, the claw 13 of the inertial sensing device 13
F already locks the ratchet wheel 9 at the moment it receives the acceleration/deceleration, that is, before the belt is pulled out, so the inertia wheel 11 stops rotating at the moment it receives the acceleration/deceleration. The unwinding rotation of No. 3 is restrained approximately at the moment when it receives the action of acceleration/deceleration.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of one embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the first embodiment, and FIG.
The figure shows the view of arrow A including a partial cutout in FIG. 1... Frame, 2, 3... Reel (axis), 3
B...Flange, 11...Inertia wheel, 6...
Seat belt, 7...first ratchet, 8...cam wheel, 14...spring.

Claims (1)

[Claims] 1: a frame 1; a reel 2 rotatably supported by the frame via a reel shaft 3; a seatbelt 6 fixed to the reel so as to be retractable; In the emergency lock type seat belt retractor, the locking device is fixed to the frame 1 and has a first ratchet in the axial direction of the reel 2. A first ratchet 7 having teeth 7A, a flange 3B that is fitted and fixed to the reel shaft 3 and has a protrusion 3D that projects outward in the axial direction, and a hole 8D that fits into the protrusion 3D of the flange. a second ratchet tooth 8B facing the first ratchet tooth 7A and guided such that it cannot rotate relative to the tooth 3B and can move in the axial direction;
a cam wheel 8 having a first cam 8C on the end face opposite to the second ratchet teeth; a spring 14 separating the flange 3B and the cam wheel 8 from each other; and a cam wheel 8 on one end face. an inertia wheel 11 which is provided with a second cam 11B that engages with the first cam 8C of the reel shaft and is loosely fitted onto the reel shaft and is held so as not to move outward in the axial direction; An emergency lock type seat belt retractor comprising a ratchet wheel 9 having three ratchet teeth 9A, and an inertia sensitive device having an engagement piece 13F that can mesh with the third ratchet teeth 9A.