JPH0245092Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a winding device for winding up occupant restraint webbing used in a seat belt device for protecting an occupant in a vehicle emergency.

[Background Art] In a seat belt device, one end of the webbing for restraining an occupant is wound up and stored in a webbing take-up device.

This webbing retractor is provided with a lock mechanism to ensure that the occupant is restrained by the webbing in the event of a vehicle emergency. As this locking mechanism, an automatic locking mechanism that prevents the webbing from being pulled out after the occupant has put on the webbing is widely used.

This automatic locking mechanism detects when the occupant attaches and releases the webbing by the rotation of the webbing take-up shaft, and controls the pawl that engages with the ratchet foil fixed to the webbing take-up shaft using a control board. It is designed to prevent the webbing from being pulled out later.

However, in conventional webbing take-up devices, the means for detecting the rotation of the take-up shaft and controlling the movement of the poles is complicated and includes a large number of parts, which may result in increased costs.

[Purpose of the invention] Taking the above-mentioned facts into account, the object of the present invention is to provide a webbing retractor that is inexpensive and has a simple structure and can reliably restrain the occupant after the occupant has attached the webbing.

[Structure of the invention] The webbing retractor according to the present invention includes a take-up shaft for winding webbing for restraining an occupant, and a lock mechanism that prevents the take-up shaft from rotating in the webbing unwinding direction when the webbing is attached to the occupant. , a winding diameter sensing means for holding the locking mechanism in a released position when a predetermined amount or more of the webbing is wound around the winding shaft, and a rotation center located at a position non-coaxial with the winding shaft. and a cam control plate that receives the rotational force of the take-up shaft via frictional force on the opposite side of the rotation center with the take-up shaft in between, and rotates relative to the take-up shaft; a rotation angle regulating means that is rotatable by a predetermined angle; a first position that is provided on the cam control plate and maintains the locking mechanism in the released state by receiving a rotational force in the webbing unwinding direction of the winding shaft; an engagement control means that receives a rotational force in the webbing winding direction of the take-up shaft and assumes a second position that enables the locking mechanism to operate;
have.

According to the above configuration, when the occupant is not wearing the webbing, the webbing is fully wound around the take-up shaft (hereinafter, this state is referred to as a fully wound state). In this state, the winding diameter sensing means holds the locking mechanism in the released position.

When the occupant unwinds the webbing from the take-up shaft in order to put on the webbing from the fully wound state, the amount of webbing wound onto the take-up shaft decreases and becomes less than a predetermined amount. Therefore, the winding diameter sensing means no longer holds the locking mechanism in the released position. In addition, although the rotation angle of the cam control plate is regulated by the rotation angle regulating means, the cam control plate receives the rotational force of the winding shaft via frictional force and winds the winding with the rotation center being at a position that is not coaxial with the winding shaft. As a result of the rotation relative to the take-up shaft, the engagement control means provided on the cam control plate receives the rotational force of the take-up shaft in the webbing unwinding direction and assumes the first position.
Therefore, the lock mechanism maintains the unlocked state. Therefore, the occupant can wear the webbing without any trouble.

After the webbing is attached to the occupant, when the webbing is slightly wound around the take-up shaft due to the occupant's breathing, etc., the cam control plate receives the rotational force of the take-up shaft via frictional force and rotates relative to the webbing. As a result, the engagement control means receives the rotational force of the take-up shaft in the webbing unwinding direction and assumes the second position. Therefore, the lock mechanism becomes capable of locking and prevents rotation of the take-up shaft in the webbing unwinding direction. As a result, the occupant is reliably restrained.

In the webbing retractor according to the present invention that operates in this manner, the rotation center of the cam control plate is located at a position that is not coaxial with the take-up shaft, and the webbing is wound on the opposite side of the rotation center across the take-up shaft. Since the cam control plate receives the rotational force of the shaft through frictional force, there is a portion of the cam control plate that receives the rotational force of the winding shaft through frictional force between the take-up shaft and the rotation center of the cam control plate. Compared to a certain structure, moment M when frictional force is external force F
The arm length L can be increased. Therefore, the cam control plate can be rotated relative to the take-up shaft by a small rotational force of the take-up shaft. Therefore, responsiveness when the cam control plate and the engagement control means provided on the cam control plate take the first position and the second position can be improved.

[Embodiment of the invention] Figs. 1 and 2 show a webbing retractor 10 to which the invention is applied.

In this webbing retractor 10, a base 12 is fixed to a vehicle body 16 with bolts 14. A pair of leg plates 18 and 20 protrude parallel to each other from both sides of the base 12, and pivotally support the vicinity of both ends of the webbing take-up shaft 22.

One end of an occupant restraining webbing 24 is locked to the intermediate portion of the winding shaft 22. Further, a mainspring spring winding device 26 is provided between the end of the winding shaft 22 protruding from the leg plate 20 and the leg plate 20, thereby attaching the winding shaft 22 in the winding direction of the webbing 24. It's spinning around.

Further, ratchet wheels 28 are fixed to the winding shaft 22 on both sides of the webbing 24 so as to rotate together with the winding shaft 22. Corresponding to this ratchet wheel 28 is a pole 30 which is pivotally supported on the leg plates 18, 20. This pole 30 has leg plate 1
8 and 20, and when engaged with the ratchet wheel 28, the webbing pull-out rotation of the take-up shaft 22 is stopped.

Further, a winding diameter sensing arm 34 is fixed to the intermediate portion of the pole 30, and the curved tip of the winding diameter sensing arm 34 is in contact with the outer surface of the webbing on the winding shaft 22. This winding diameter sensing arm 34 is connected to the webbing 2
When a predetermined length of webbing 24 or more is wound around the winding shaft 22 by the mainspring spring winding device 26, the outer diameter of the webbing 24 increases and the pole 3
0 in a disengaged position with the ratchet wheel 28. However, when the passenger pulls out and attaches the webbing 24, the outer diameter of the webbing 24 becomes smaller, so the pole 3
0 can be engaged with the ratchet wheel 28.

Leg plate 18 of winding shaft 22 and ratchet foil 28
A cam control plate 36 is arranged in between. The cam control plate 36 has its upper end connected to the leg plate 1 by a support shaft 38.
The winding shaft 8 is rotatably attached to the inner surface of the winding shaft 8, and a front hole 40 is formed in the center thereof to receive the end of the winding shaft 22. Further, a spring 42 is provided on the back surface of the cam control plate 36, and a portion of the spring 42 is in pressure contact with the surface of the ratchet wheel 28. For this reason,
When the take-up shaft 22 rotates, the cam control plate 36 pivots about the support shaft 38 by an angle regulated by the front hole 40 due to the frictional force between the cam control plate 36 and the take-up shaft 22 . Here, the support shaft 38 is the center of rotation of the cam control plate 36, and when the distance from this support shaft 38 to the spring 42 is the frictional force F, the moment M applied to the cam control plate 36 is
The length of the arm is L.

The spring 42 may have a structure in which a part of the cam control plate 36 is cut and raised, or a protrusion is provided to press the spring 42 against the ratchet wheel.

A first protrusion 44 is provided on the outer periphery of the lower end of the cam control plate 36.
and second protrusions 46 are formed at predetermined intervals,
The pole 30 is in contact with the first protrusion 44 . Since the tension coil spring 48 is connected to the pawl 30, the pawl 30 is biased counterclockwise in FIG. 2, that is, in the direction of engagement with the ratchet wheel 28. However, as can be seen from FIG. 4, while the webbing 24 is being unwound, the first protrusion 44 of the cam control plate 36 prevents the pawl 30 from engaging.
This state is the first position of the engagement control means.

Further, when the winding shaft 22 rotates in the webbing winding direction, the cam control plate 36 turns by a predetermined angle in the same direction as shown in FIG.
This corresponds to the protrusion 44 and the second protrusion 46 . This state is the second position of the engagement control means, and the pawl 30 is ready to engage the ratchet wheel 28. When the cam control plate 38 further rotates in the winding direction, it becomes the state shown in FIG.
Push 0 up.

The webbing retractor 10 of this embodiment configured as described above performs an automatic locking operation, and the operating order is as follows.

1 and 2 show the webbing 24 in a fully wound state when the occupant has released the webbing 24 from being attached. In order to attach the webbing 24, the occupant can attach the intermediate portion of the webbing 24 by pulling out an end (not shown) of the webbing 24 and engaging the tongue plate attached to this end with the buckle device.

When the webbing is fully wound, the pole 30 is pressed down by the winding diameter sensing arm 34, and the second protrusion 46 is in contact with the pole 30 as shown in FIG. Even if the outer diameter of the webbing 24 around the take-up shaft 22 is reduced, the pawl 30 will not engage the ratchet wheel 28.

When the occupant wears the webbing 24, the webbing 24 may move slightly toward the winding shaft due to slight changes in the occupant's posture and changes in the abdomen caused by breathing, before or immediately after the occupant assumes the driving position. 22.

As a result, the cam control plate 36 also pivots counterclockwise about the support shaft 38, and the action of preventing the pawl 30 from pivoting by the first protrusion 44 is released, as shown in FIG. Therefore, as shown in FIG. 3, the pawl 30 engages with the ratchet wheel 28 by the biasing force of the tension coil spring 48, and rotation of the take-up shaft 22 in the webbing unwinding direction is prevented. Therefore,
In the event of a vehicle emergency, the occupant is securely restrained by the webbing 24 to ensure safety.

Note that since the ratchet wheel 28 has a sawtooth shape, it is possible to wind the webbing 24 around the winding shaft 22. Therefore, when the webbing 24 is attached to a passenger or luggage, a reliable restraining force can be obtained by the automatic locking action.

When the webbing unwinding stop of the winding device is canceled, the tongue plate is removed from the buckle and the entire amount of the webbing 24 is wound onto the winding shaft 22. At the time of winding, the second protrusion 4 is
6 pushes up the pawl 30, so there is no collision noise between the pawl 30 and the ratchet wheel 28 during winding.

In addition, since the distance from the support shaft 38 to the spring 42, that is, the arm length L of the moment M applied to the cam control plate 36 when the frictional force is F, is long, even if the frictional force F is small, it can be performed reliably and quickly. Cam control board 36
The cam control plate 36 and the cam control plate 3 can be rotated relative to the winding shaft 22.
The responsiveness of the first protrusion 44 and the second protrusion 46 provided in the second protrusion 6 can be improved. For this reason, the webbing 24 is slightly wound around the take-up shaft 22 immediately after the passenger engages the tongue plate with a buckle device (not shown), that is, when the first protrusion 44 and the pawl 30 are engaged as shown in FIG. Once removed, the cam control plate 36 responds quickly through the frictional force between the spring 42 and the ratchet wheel 28, and the pawl 30 is instantaneously engaged with the ratchet wheel 28, as shown in FIG. Therefore, after the crew member engages the tongue plate with the buckle device, the webbing 24
is not unnecessarily wound onto the winding shaft 22.
As a result, the webbing 24 never gives the occupant a feeling of pressure.

Note that the pawl 30 may be provided above the ratchet foil 28 so that it engages with the ratchet foil 28 by its own weight.

[Effects of the invention] As explained above, in the webbing retractor according to the present invention, the lock mechanism prevents the webbing from being unwound from the rewinding shaft by the cam control plate, the rotation angle regulating means, the winding diameter sensing means, and the engagement control means. Since it is controlled whether or not to prevent directional rotation, the occupant can be reliably kept in a restrained state after the webbing is attached with a simple structure.

[Brief explanation of the drawing]

FIG. 1 is a partial vertical cross-sectional view of a webbing retractor according to the present invention, FIG. 2 is a cross-sectional view taken along the line - FIG. 1, and FIGS. 3 and 4 are operational views of FIG. 2. DESCRIPTION OF SYMBOLS 10... Webbing winding device, 22... Winding shaft, 24... Webbing, 28... Ratchet wheel (lock mechanism), 30... Paul (lock mechanism), 34... Winding diameter sensing arm (winding diameter sensing means) ),
36... Cam control plate, 40... Front hole (rotation angle regulating means), 44... First protrusion (engagement control means), 48
...Tension coil spring (lock mechanism).

Claims (1)

[Scope of utility model registration request] a take-up shaft for winding up webbing for restraining an occupant; a lock mechanism for preventing rotation of the take-up shaft in a webbing unwinding direction when the webbing is attached to an occupant; a winding diameter sensing means for holding the locking mechanism in a released position in a state in which the locking mechanism is held in a released position; a cam control plate that receives the rotational force of the take-up shaft via frictional force and rotates relative to the take-up shaft; a rotation angle regulating means that allows the cam control plate to rotate by a predetermined angle; and the cam. a first position provided on a control plate for maintaining the lock mechanism in the released state in response to a rotational force of the take-up shaft in the webbing unwinding direction; and a first position of the lock mechanism provided in the control plate in response to the rotational force of the take-up shaft in the webbing unwinding direction; an engagement control means that assumes a second position to enable locking operation of the webbing retractor.