JPH0723321Y2 - Belt winding device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a device for retracting a seat belt for protecting an occupant such as a vehicle.

(Prior Art and Problems Thereof) A winding spring is used for winding a belt in a belt winding device. In this case, the winding force of the winding spring acts even when the occupant pulls out the belt in the seated posture and finishes wearing the belt, which gives the occupant a feeling of pressure and hinders comfortable driving.

Therefore, various belt winding devices have conventionally been proposed in which a mechanism is added to reduce the winding force of the winding spring while the occupant is wearing the belt (hereinafter also referred to as tensionless).

As a tensionless device, when the occupant wears the belt, the belt must fit the occupant without giving the occupant a feeling of pressure by the belt. When the occupant takes a posture, the belt easily follows the movement of the occupant and is pulled out from the belt retractor.When the occupant returns to the normal posture, the belt moves to the retractor up to the position before the first belt withdrawal. It is desired that the film be immediately wound and returned to the tensionless state again, and a structure having such conditions is provided, for example, Japanese Patent Laid-Open No. 56-124532.
A device such as the one disclosed in Japanese Patent Publication has been proposed.

However, when the occupant wears the belt, the above-mentioned conventional device allows the reel shaft belt to be wound up until the belt excessively pulled out by the occupant fits the occupant's body, and the belt is not worn by the occupant. After it fits into the vehicle, the frame is complicated to pull out the belt slightly to stop the reel shaft from winding the belt and put the belt in tensionless state. Even if the occupant returns to the normal position before moving, it returns to the tensionless state again, that is, the frame for storing the tensionless initial position is also complicated, resulting in an increase in the number of parts and an increase in cost. There is a problem called.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a belt retractor having a tensionless mechanism, which has a simple mechanism and can reduce the number of parts and cost. is there.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention uses a belt winding spring mounted on a reel shaft rotatably supported by a frame and using the winding spring. In a belt winding device that applies a winding force to a belt by rotating a reel shaft, a ratchet wheel that rotates integrally with the reel shaft and that has a boss, and is coaxially and frictionally slidably attached to the ratchet wheel. At the same time, a clutch plate having a first cam surface and a second cam surface projecting from the first cam surface on a part of its peripheral surface, and a notch portion formed at a position different from these cam surfaces, A pawl lever having a pawl that can be displaced between a position where the ratchet wheel of the ratchet wheel is engaged and a position where the ratchet tooth is separated from the pawl lever, and the pawl lever. Is rotatably attached to the ratchet wheel, and the rotation support portion contacts the boss portion of the ratchet wheel when the rotation support portion contacts the first cam surface of the clutch plate. It has a friction plate having a stepped surface that is displaced to a position where it is disengaged from the boss when it comes into contact with the notch, and a solenoid mechanism that rotationally displaces the pawl lever.

(Operation) The pawl lever is rotated by the excitation of the solenoid, and the movement of the friction plate at this time is controlled by the abutment positions on the first and second cam surfaces and the notches provided on the clutch plate to ratchet the pawl. Tensionless or release is performed by engaging and disengaging with.

(Example) Hereinafter, the present invention will be described in detail with reference to an example.

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention, and FIG. 2 is a side view taken along the line XX of FIG.

Reference numeral 1 denotes a frame, which includes both side plates 1A and 1B. A reel shaft 2 is rotatably supported between the both side plates, and an end portion of the reel shaft 2 projects outward through a retainer 4 attached to the outside of one side plate 1A. A belt reel 3 around which a belt BL is wound is integrally fixed to the reel shaft 2 so as to rotate together with the reel shaft. The reel shaft 2
A ratchet wheel 11 is fitted and fixed to the outward protruding end of the. This ratchet wheel 11 is integrally formed with a boss portion 11A and a ratchet plate 11B having ratchet teeth 11b facing the belt winding direction.
A ring groove is formed on the outer circumference. Reference numeral 8 denotes a clutch plate, which is attached to the outer periphery of the boss portion 11A of the ratchet wheel to the side surfaces of the C ring 10 and the ratchet plate 11B fitted in the ring groove to attach the clutch plate 8 to the C ring side. Energizing clutch spring 9
It is mounted so that it can slide frictionally. Reference numeral 5 denotes an L-shaped pawl lever rotatably attached to a pin 4C provided on a cover 15 fixed to the side plate 1A of the frame 1.
The pawl lever 5 is rotatably mounted with a friction plate whose shape will be described later in detail. A solenoid 16 is provided with a plunger 17 connected to one end of the pawl lever 5 (a solenoid mechanism is constituted by 16, 17). Reference numeral 14 denotes a belt winding spring mounted between the outer protruding end of the ratchet wheel 11 and the cover 15A, and an emergency lock mechanism (not shown) is provided on the outer surface of the side plate 1B, and the cover 20 is provided thereon. It is fixed.

Next, the relationship between the concrete structure of the clutch plate 8, the pawl lever 5, the friction plate 18 and the ratchet plate 11B, the solenoid 16 and the like will be described with reference to FIG.

The clutch plate 8 has a cam projection 8C (first cam surface) on a part of its circumferential surface, and a notch 8A is formed on the circumferential surface near the cam projection 8C. Has been done. The cam protrusion 8C further has an arc-shaped protrusion 8B (second cam surface) protruding from the peripheral surface thereof. The ratchet plate 11B located on the rear surface of the clutch plate 8 in the drawing has a diameter slightly smaller than the diameter of the clutch plate 8 so that the ratchet teeth can be seen through the notch 8A of the clutch plate 8. There is.
In addition, the protruding height of the extended step portion 8D of the arc-shaped protruding portion 8B is the same as that of the first
It is set to be higher than the protrusion height of the cam protrusion 8C.

The pawl lever 5 has an L shape, and the bent portion of the pawl lever 5 has a pin.
A pawl 5C rotatably supported by 4C, engaged with a tip pin 17B of a plunger 17 of a solenoid 16 through a long hole 5E formed at one end, and capable of meshing with the ratchet plate 11B at the other end tip. Are formed.

The friction plate 18 is rotatably supported by a pin 5D provided on the pawl lever 5 at one end rotation supporting portion 18C, and has a step surface 18A at the other end and a projecting surface 18B protruding from a part of the step surface. The inner surface of the protruding surface 18B is urged by a spring 19 mounted between a part of the rotation support portion 18C and the cover so as to contact the boss portion 11A of the ratchet wheel.

The cam projection 8C of the clutch plate 8 is in contact with the peripheral surface (point) of the rotation support 18C of the friction plate 18.

The solenoid 16 is excited when a buckle (not shown) at the front end of the belt is engaged, and the plunger 17 is pulled in the Z direction in the figure.

In the figure, the arrow B direction is the belt winding direction, and the arrow A direction is the belt withdrawing direction.

Next, the operation of the device will be described with reference to FIGS. 3 (a), 3 (b) and 3 (c). The operation of the device will be described.

<When the belt is not used> In this case, since the buckle of the belt is not engaged, the solenoid 16 is not excited and the plunger 17 is in a state of being projected by the holding force of the plunger spring 17A. Therefore, the pawl lever 5 also has a ratchet plate 11
The friction plate 18 is held at a position away from B, and the tip projection 18B of the friction plate 18 also has a ratchet wheel 11
It is held at a position engaged with the peripheral surface of the boss portion 11B (state shown in FIG. 2).

<When the belt is worn> Next, when the occupant pulls out the belt for wearing the belt, the ratchet plate 11B and the clutch plate 8 rotate together with the reel shaft 2 in the arrow A direction, but the clutch slidably connected to the ratchet plate 11B. Plate 8
Only the arc-shaped protrusion of the outer peripheral cam portion of the clutch plate 8 is shown.
8B is rotated to a position (position shown in FIG. 2) where it comes into contact with the outer surface of the fulcrum 5F of the pawl lever 5 and stopped (FIG. 3 (a)).

Next, after pulling out the belt to a length required for the occupant to wear the belt, when a buckle (not shown) is engaged, the buckle switch provided in the buckle causes the solenoid 16
Is excited, the plunger 17 is attracted against the biasing force of the plunger spring 17A, and the pawl 5C is ratcheted.
The pawl lever 5 is rotated in the direction to engage with 11B, but the friction pin 5D comes into contact with the cam surface 8C of the clutch plate 8 at the point of FIG. 3 (a) and its rotation is hindered. Since the pawl lever 5 is stopped in the state shown by the chain line, the pawl 5C does not engage with the ratchet teeth of the ratchet plate 11B.

Next, the belt is wound until it fits the occupant, and the reel shaft 2 rotates in the direction of arrow B. Therefore, the clutch plate 8 and the reel shaft 2 are also shown in FIG.
From the above state, it rotates in the direction of arrow B and comes into contact with the friction pin 5D at a point D in FIG. 3 (b) to stop in the state shown in FIG. 3 (b). At this time, the pawl lever 5 is a solenoid
The pawl 5C is rotated in the direction of engaging the ratchet teeth of the ratchet plate 11B by the urging force of 16, but the step surface 18A of the friction plate 18 contacts the lower surface of the boss 11A of the ratchet wheel 11 at a point, and the rotation thereof is The pawl 5C and the ratchet teeth do not engage due to being hindered, which is why
The belt continues to be wound until it fits the occupant.

Next, when the belt is slightly pulled out from the state of FIG. 3 (b), the clutch plate 11B rotates in the direction of arrow A together with the reel shaft 2, and the step surface 18A of the friction plate 18 becomes
By friction with the boss 11A of the ratchet wheel 11, the ratchet wheel 11 is guided to the right of the lower surface of the boss portion 11A, and then the friction pin 5D of the pawl lever 5 is moved to the clutch plate 8
The notch portion 8A enters into the notch portion 8A by the urging force of the solenoid 16 and the pawl 5C.
Is engaged with the teeth of the ratchet plate 11B and is shown in FIG. 3 (C).
As a result, the state in which the belt winding spring 14 rotates the reel shaft 2 in the belt winding direction is obstructed and the occupant's sense of pressure due to the belt tension is removed. That is, the state becomes tensionless.

In the case where the belt is pulled out and rotated in the “G” region from this state, the belt is wound up to the first tensionless position and returns to the tensionless state again. That is, the initial tensionless position is memorized with respect to the belt withdrawal rotation in the "G" region, but the relative relationship between the clutch plate 8, the pawl lever 5 and the friction plate 18 with respect to the belt withdrawal beyond the "G" region. Is in the state of FIG. 3 (a) (the pawl lever is in the chain line position), and the tensionless state is released. That is, the friction pin 5D of the pawl lever 5 resists the bias of the plunger spring 17A by the rotation of the clutch plate in the belt withdrawing direction due to the belt withdrawing beyond the "G" region range, and from the notch 8A of the clutch plate 8 to the G region range. Since it is pushed up on the cam surface of the first cam surface 8C and then on the cam surface of the first cam surface 8C, the step surface 18A of the friction plate 18 is the ratchet wheel 1
It moves downward from the lower surface of the boss portion 11A of 1. Therefore, the friction plate 18 is set by the spring 19 so that the protruding surface 18
The inner surface of B contacts the boss portion 11A of the ratchet wheel 11. As a result, even if the belt is wound around the reel and the clutch plate 8 rotates together with the reel shaft in the direction of FIG. 2B (clockwise direction), the step surface of the friction plate
Even if 18A contacts the boss portion 11A of the ratchet wheel and the pawl lever 5 is biased upward by the solenoid 16, the engagement of the ratchet wheel 11 of the pawl 5C with the ratchet teeth 11B is prevented. Therefore, in order to return to the tensionless state again, the belt is wound up to the state shown in FIG. 3 (b), and then the belt is pulled out until the state shown in FIG. 3 (c) is obtained again.

When the occupant releases the engagement of the buckle, the buckle switch demagnetizes the solenoid 16 and the pawl lever 5 and the friction plate 18 return to the state shown in FIG. 2 to wind the belt.

[Effect of the Invention] According to the present invention described in detail above, the solenoid that is excited when the buckle is engaged with the pawl lever that reduces the belt winding force by engaging with the ratchet teeth of the ratchet wheel that is integrally provided with the reel shaft. However, when the occupant wears the belt, the belt that is pulled out excessively is pulled up by the friction plate provided on the pawl lever until the belt fits to the occupant. Rotation is allowed, and the occupant pulls out the belt slightly so that the tension is in a tensionless state.In addition, one clutch plate must also release the tensionless state when the occupant pulls the belt back and forth within a certain range. Not allowed. Therefore, the structure is extremely simple, the number of parts is small, and the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention, and FIG.
The figure is a sectional view taken along the line X-X of FIG. 1 as viewed in the direction of the arrow Y, and FIGS. 3 (a), (b), and (c) are sectional views for explaining the operation. 1 ... frame, 2 ... reel shaft, 3 ... belt reel, 5 ... pawl lever, 8 ... clutch plate, 16 ... solenoid, 17 ... plunger, 18 ... friction plate, BL ... belt.

Claims (1)

[Scope of utility model registration request] 1. A belt winding device, wherein a belt winding spring is attached to a reel shaft rotatably supported by a frame, and a winding force is applied to a belt by rotation of the reel shaft by the winding spring. A ratchet wheel that rotates integrally, a pawl lever having a pawl that can be engaged with and disengaged from ratchet teeth of the ratchet wheel, and a solenoid frame that rotates the pawl lever to disengage the pawl of the lever from the ratchet teeth of the ratchet wheel. And a first cam mounted coaxially with the ratchet wheel so as to be frictionally slidably rotatable to prevent engagement between both the pawl of the pawl lever and the ratchet teeth of the ratchet wheel during excitation of the solenoid frame. Clutch having a surface and a cutout portion that allows engagement between the both surfaces And a step surface that is rotatably attached to the pawl lever and engages with a boss portion of the ratchet wheel, and after the initial excitation of the solenoid frame, the pawl lever is rotated until the reel shaft slightly rotates in the belt withdrawing direction. Belt take-up device including a friction plate that holds a pawl lever at a position where the pawl of the ratchet does not engage with the ratchet teeth of the ratchet wheel.