JP6774376B2 - Seat belt retractor - Google Patents

Description

The present invention relates to a seatbelt retractor installed in a vehicle such as an automobile, and particularly relates to a seatbelt retractor having a tension reducer (TRD) function that reduces the urging force of a spring that winds up the seatbelt when the seatbelt is normally worn.

The seatbelt device installed in a vehicle such as an automobile restrains the occupant with the seatbelt in an emergency such as when the vehicle has a large deceleration in the event of a vehicle collision to prevent the occupant from inertial movement from the seat. It protects the occupants. This seatbelt device is provided with a seatbelt retractor that winds up and pulls out the seatbelt with a spindle and prevents the seatbelt from being pulled out in an emergency.

In such a seatbelt retractor, when the occupant sits on the seat and pulls out the seatbelt, and the tongue is inserted into the buckle and engaged, the excess drawer is absorbed and is unnecessary on the occupant's chest or the like in the normal wearing state. It is preferable not to give a feeling of oppression. However, in a general seatbelt retractor, the spindle is constantly urged in the belt winding direction by the urging force of the spring that exerts a certain force, so that the occupant may feel oppressive during normal wearing.

Therefore, a seatbelt retractor having a tension reducer (TRD) function that reduces the urging force of a spring that winds up the seatbelt when the seatbelt is normally worn is provided. In a seatbelt retractor equipped with a tension reducer (TRD) function, the spring means for urging the seatbelt in the winding direction is configured in advance by dividing it into a main spring and an additional spring, and during normal belt winding, both springs A sufficient belt winding force is created by the synthetic urging force, and when the seat belt is normally fastened, tension is applied to the seat belt by a weak winding force only by the urging force of the main spring. Switching between the operating state of both the main spring and the additional spring and the operating state of only the main spring is generally controlled by using a memory means (see, for example, Patent Document 1).

In the seatbelt retractor having the tension reducer (TRD) function described in Patent Document 1, the memory means is rotatably arranged on a bush shaft having a lever and rotating together with the spindle and a ratchet wheel, and is intermittently arranged by the lever. It is composed of a driven Geneva gear. When the tension reducer function ON, which regulates the rotation of the ratchet wheel in the belt winding direction, the relative rotation amount of the spindle (bush shaft) with respect to the ratchet wheel is stored as the rotation number of the Geneva gear when the seat belt is wound. ..

Japanese Unexamined Patent Publication No. 2006-347199

However, in the seat belt retractor of Patent Document 1, when the tension reducer function is released, the ratchet wheel whose rotation in the belt winding direction is restricted rotates rapidly, and the Geneva gear shortens with the rotation of the ratchet wheel. Since it rotates at a stretch, there is a problem that an abnormal noise is generated due to the impact of the stopper of the Geneva gear contacting the lever of the bush shaft. In particular, when such a seatbelt retractor with a tension reducer function is located near the occupant's ears, the occupant feels a great deal of discomfort.

There is also a seatbelt retractor in which the memory means is composed of memory tape and the amount of rotation relative to the spindle with respect to the ratchet wheel is stored as slack in the memory tape, but the slack memory tape is stored when the tension reducer function is released. Since all the tapes are in close contact with each other in a short time, an abnormal noise may be generated due to the impact when the tape is wound.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is a seatbelt capable of reducing an unpleasant noise generated by abrupt rotation of the rotating memory mechanism when the tension reducer is released. To provide a retractor.

The above object of the present invention is achieved by the following configuration.
(1) A spindle around which the seat belt can be wound and pulled out, and
A main spring composed of a spiral spring whose inner end is connected to the spindle and whose outer end is connected to a fixed side member to constantly apply an urging force in the belt winding direction to the spindle.
A secondary spring composed of a spiral spring, which is arranged in parallel with the main spring and whose outer end is connected to the fixed side member to selectively apply an urging force in the belt winding direction to the spindle. When,
A ratchet wheel to which the inner end portion of the sub-spring is connected, is rotatably provided coaxially with the spindle, and has a plurality of ratchet teeth on the outer peripheral portion.
A regulated state in which the ratchet wheel is provided with a claw portion that can be engaged with the ratchet tooth portion, the ratchet wheel is allowed to rotate in the belt pull-out direction, and the rotation in the belt winding direction is regulated, and the belt pull-out direction of the ratchet wheel. And a switching device that selectively switches between a release state that allows rotation in both directions of the belt winding direction, and
A rotation memory mechanism that stores the relative rotation amount of the spindle with respect to the ratchet wheel in the regulated state, and
It is a seatbelt retractor equipped with
One end is fixed to the ratchet wheel or a member rotating with the ratchet wheel, and the other end is provided with a ring-shaped friction spring having a free end.
When the restricted state of the ratchet wheel is released by the switching device, the friction spring expands in diameter due to the rotation of the ratchet wheel, so that the friction spring is in sliding contact with the fixed side member, and the friction spring and the fixed are fixed. A seat belt retractor characterized in that a braking force is applied to the ratchet wheel by a frictional force with a side member.
(2) A weight is fixed to the other end of the friction spring.
The seatbelt according to (1), wherein when the restricted state of the ratchet wheel by the switching device is released, the diameter of the friction spring is expanded by the centrifugal force acting on the weight due to the rotation of the ratchet wheel. Retractor.
(3) The member that rotates together with the ratchet wheel is a cover that is attached to the ratchet wheel and that accommodates the rotating memory mechanism in cooperation with the ratchet wheel.
The seatbelt retractor according to (1) or (2), wherein the one end portion of the friction spring is fixed to the side surface of the cover.
(4) The rotary memory mechanism is configured by spirally winding a long strip-shaped member, is arranged in series with the auxiliary spring, and its inner end is connected to the spindle, and its outer end thereof. The seatbelt retractor according to any one of (1) to (3), wherein the portion is a memory member connected to the ratchet wheel.

The term "connected to the spindle" includes a case where the spindle is directly connected to the spindle and a case where the spindle is connected to the spindle via a member (for example, a retainer or a connector of the present embodiment) that rotates integrally with the spindle.

According to the seatbelt retractor of the present invention, when the tension reducer is released, it is possible to suppress an increase in the rotation speed of the rotary memory mechanism and reduce an unpleasant abnormal noise generated by the rapid rotation of the rotary memory mechanism. A capable seatbelt retractor can be provided.

It is a main part exploded perspective view of the seat belt retractor of one Embodiment of this invention. It is a side view of the seat belt retractor shown by removing the 3rd housing. FIG. 2 is a cross-sectional view taken along the line III-III in FIG. It is a perspective view of the friction spring and the weight arranged on the side surface of the cover fixed to a ratchet wheel. (A) is a perspective view of the friction spring of the first modified example, and (b) is a sectional view taken along line VV of FIG. 5 (a). (A) is a perspective view of the friction spring of the second modified example, and (b) is a sectional view taken along line VI-VI of FIG. 6 (a). (A) is a perspective view of the friction spring of the third modified example, and (b) is a sectional view taken along the line VII-VII of FIG. 7 (a). It is a schematic diagram for demonstrating the operation of a seatbelt retractor when TRD is OFF. It is a schematic diagram for demonstrating the operation when the seat belt is further pulled out from the state which TRD is ON. It is a schematic diagram for demonstrating the operation when a webbing is rewound in a state where TRD is ON. It is a schematic diagram for demonstrating the operation when TRD is switched from ON to OFF. It is a schematic diagram for demonstrating the operation when TRD is turned off and webbing is rewound. It is a graph which shows the state which the rotation speed of a ratchet wheel is suppressed by the braking force of a friction spring when TRD is switched from ON to OFF. As a modification of the rotary memory mechanism, it is a perspective view of a main part when a wobble gear mechanism is used. It is a perspective view which looked at the ratchet wheel which concerns on the modification of FIG. 14 from the side opposite to FIG.

Hereinafter, the seatbelt retractor according to the embodiment of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, the seatbelt retractor 1 of the present embodiment rotates the spindle 10 around which the webbing B (see FIG. 8) is wound so that it can be wound and pulled out, and the spindle 10 between the left and right side walls 8a and 8b. A frame 8 that freely supports the frame 8, a winding mechanism 2 provided on the side wall 8a side of the frame 8 and having a tension reducer (TRD) function, and a winding mechanism 2 provided on the side wall 8b side of the frame 8 for a vehicle in the event of a vehicle collision or the like. It has a sensor mechanism 5 that detects an emergency in which a large deceleration occurs and prevents the seatbelt from being pulled out.

The take-up mechanism 2 is arranged in parallel with the main spring 21 that constantly applies the urging force of the belt take-up direction RA to the spindle 10 and the main spring 21, and applies the urging force of the belt take-up direction RA to the spindle 10. A memory member 23 as a rotary memory mechanism, a ratchet wheel 40, and a cover, which are arranged in series with a sub-spring 22 to be selectively applied and a long strip-shaped member is wound in a spiral shape. It has a lock arm 60 that selectively rotates and locks the ratchet wheel 40 in one direction, and an electromagnetic solenoid 70 that switches and displaces the lock arm 60 between a lock position and an unlock position. Further, the winding mechanism 2 has a ring-shaped friction spring 51, a weight 55, and a circular shape of the third housing 33, which will be described later, as a mechanism for reducing abnormal noise due to winding of the memory member 23 when the tension reducer is released. It has a sliding contact surface 33c, which is an inner peripheral surface. The tension reducer (TRD) is mainly composed of the above elements of the winding mechanism 2 excluding the main spring 21.

Further, the winding mechanism 2 has a first housing 31, a second housing 32, and a third housing 33. These housings 31, 32, 33 accommodate and support the main spring 21, the sub spring 22, the memory member 23, the ratchet wheel 40, the cover 48, the friction spring 51, and the weight 55, and are used as fixed side members on the frame 8. On the other hand, it is fixed directly or indirectly. With reference to FIG. 3, the first housing 31, the second housing 32, and the third housing 33 are arranged in this order from the outside (the side far from the left side wall 8a of the frame 8) of the spindle 10 in the axial direction to the inside (frame 8). Lined up toward the left side wall 8a). In the present embodiment, the second and third housings 32 and 33 are fitted and fixed to the first housing 31, and the first housing 31 is fixed to the side wall 8a of the frame 8.

Therefore, the main spring 21 is arranged between the first housing 31 and the second housing 32, and the sub spring 22, the ratchet wheel 40, the memory member 23, the cover 48, the friction spring 51, and the weight 55 are the second housing 32. It is arranged between the third housing 33 and the third housing 33. As shown in FIG. 2, the lock arm 60, the electromagnetic solenoid 70, and the like are housed by the cover portion 31s integrally formed with the first housing 31 and the case portion 33s integrally formed with the third housing 33. Has been done.

The shaft end 11 of the spindle 10 penetrates the central hole 33a of the third housing 33 fixed to the left side wall 8a of the frame 8, and the retainer 12 is coupled to the shaft end 11 so as to rotate integrally with the spindle 10. ing.

As shown in FIGS. 1 and 3, the retainer 12 is fitted into the square hole of the connector 13 through the cylindrical support portion 12a that rotatably supports the ratchet wheel 40 and the central hole of the ratchet wheel 40. A square shaft portion 12b and a tip protrusion portion 12c that penetrates the connector 13 and is rotatably supported by a bearing hole 31a on the inner surface of the first housing 31 are provided. Further, a large-diameter cylindrical support portion 12e that fits into the fitting hole 48c of the cover 48 is provided at the base portion (third housing 33 side) of the retainer 12.

The outer end 21a of the main spring 21 is locked to the first housing 31, and the inner end 21b is locked to the spring locking portion 13a of the connector 13. The connector 13 is coupled so as to rotate integrally with the spindle 10 via a retainer 12 in which the square shaft portion 12b fits into the square hole. As a result, the main spring 21 constantly applies the urging force of the belt winding direction RA to the spindle 10 via the connector 13 and the retainer 12 in a state with reference to the first housing 31.

Further, in the auxiliary spring 22 arranged on the outer side in the axial direction of the ratchet wheel 40, the outer end portion 22a is locked to the second housing 32, and the inner end portion 22b is spring-locked to the boss cylinder portion 44 of the ratchet wheel 40. It is locked to the portion 45 (see FIG. 3). As a result, the secondary spring 22 applies the urging force of the belt winding direction RA to the ratchet wheel 40 in a state with reference to the second housing 32.

The main spring 21 and the sub spring 22 are composed of spiral springs (also referred to as springs) having the same spiral direction. The spiral springs of the main spring 21 and the sub spring 22 have a function of storing energy (torque) by being wound in the winding direction and releasing energy (torque) in the winding loosening direction (opposite to the winding direction). Is.

The torque (rotational urging force) of the main spring 21 and the sub spring 22 can be arbitrarily set, and may be set to be equal to each other, for example. Further, the torque of the sub spring 22 may be set larger than the torque of the main spring 21 in order to give a large difference to the winding force applied to the spindle 10 when the tension reducer is turned on / off.

The memory member 23 housed inside the tubular wall 42 of the ratchet wheel 40 is locked to the tape fixing portion 48f of the cover 48 whose outer end portion 23a is integrally fixed to the ratchet wheel 40. That is, the outer end portion 23a of the memory member 23 is connected to the ratchet wheel 40 via the cover 48. Further, the inner end portion 23b of the memory member 23 is locked to the retaining groove 12d formed in the retainer 12.

The memory member 23 is, for example, a long tape (strip-shaped member) in which a resin such as polyamide (PA6) having high impact resistance is stretched, and is arranged in series with the sub spring 22 to form a main spring 21 and a sub spring. It is spirally wound in the same direction as 22. The memory member 23 does not have an energy (torque) storage function, and when the tension reducer is turned off, the tapes adjacent to each other in the radial direction are wound tightly by the spring force of the main spring 21 and the sub spring 22. It has a shape. Further, when the tension reducer is turned on, the winding is loosened. The memory member 23 stores the relative rotation amount of the spindle 10 with respect to the ratchet wheel 40 in the regulated state.

The ratchet wheel 40 has a large-diameter tubular wall 42 projecting from the side surface of the circular substrate 41 on the third housing 33 side (inside), and ratchet teeth 43 are provided on the outer periphery of the tubular wall 42 at regular intervals in the circumferential direction. It is an array. A cover 48 is attached to the side surface of the third housing 33 side (inside) inside the tubular wall 42 having the ratchet tooth portion 43 formed on the outer circumference, and the ratchet wheel 40 and the cover 48 accommodate the memory member 23. .. Further, a small-diameter boss cylinder portion 44 having a spring locking portion 45 is formed on the outer periphery around the central hole on the opposite side (outside) side surface of the circular substrate 41 of the ratchet wheel 40.

The cover 48 is integrally fixed to the ratchet wheel 40 by engaging a plurality of mounting claws 48b provided around the circular substrate 48a with the mounting holes 46 formed in the circular substrate 41 of the ratchet wheel 40. Further, at the center of the cover 48, a fitting hole 48c that fits into the large-diameter cylindrical support portion 12e of the retainer 12, which will be described later, is provided.

As shown in FIG. 4, a boss portion 48d projecting toward the third housing 33 is provided on the outer peripheral side of the circular substrate 48a on the side surface of the circular substrate 48a of the cover 48 on the third housing 33 side (inside). .. A radial hole 48e through which the friction spring 51 is inserted is formed in the boss portion 48d. Further, a spring receiving portion 48g is formed which is separated from the boss portion 48d in the circumferential direction (counterclockwise in FIG. 4) and is located on the inner diameter side in the radial direction from the boss portion 48d and projects toward the third housing 33 side. There is. Further, on the outer peripheral side of the circular substrate 48a, a plurality of substantially L-shaped cross sections (6 in the present embodiment) extending outward in the radial direction after projecting from the circular substrate 48a toward the third housing 33 side. The spring accommodating portions 48h are provided apart from each other in the circumferential direction. A friction spring 51 is mounted on the outer peripheral side of the spring accommodating portion 48h having a substantially L-shaped cross section.

The weight 55 is a substantially rectangular parallelepiped member having a predetermined mass, and a U-shaped groove 56 to which the friction spring 51 is fixed is formed at a substantially central portion in the longitudinal direction thereof.

Then, as shown in FIG. 4, one end portion 53 of the friction spring 51 is formed in a substantially crank shape, and after being inserted into the radial hole 48e of the boss portion 48d of the cover 48, the spring receiving portion 48g is on the inner diameter side. An arcuate portion that is supported by the spring and faces the other end 54 is attached to the outer peripheral side of the plurality of spring accommodating portions 48h. Further, the substantially U-shaped other end portion 54 of the friction spring 51 is inserted into the U-shaped groove 56 of the weight 55 and holds the weight 55 by elastic force. As a result, the weight 55 is attached to the other end 54 of the friction spring 51 so as to be closer to the inner diameter than the outer peripheral surface of the friction spring 51.
Therefore, one end 53 of the friction spring 51 is a fixed end fixed to the cover 48, and the other end 54 holding the weight 55 is a free end that can move in the radial direction.

As shown in FIG. 3, in the normal state in which the rotation of the ratchet wheel 40 is stopped, the friction spring 51 is axially separated from the ratchet tooth portion 43 of the ratchet wheel 40, and the sliding contact surface of the third housing 33. Facing 33c. A gap C of 1.0 mm or less is provided between the friction spring 51 and the sliding contact surface 33c of the third housing 33, for example.

Then, when the cover 48 and the friction spring 51 rotate with the rotation of the ratchet wheel 40, the friction spring 51 expands in diameter due to the centrifugal force acting on the weight 55, and the friction spring 51 slides on the sliding contact surface 33c of the third housing. Touch. The sliding resistance acting between the friction spring 51 and the sliding contact surface 33c of the third housing suppresses an increase in the rotational speed of the ratchet wheel 40.

The sliding resistance between the friction spring 51 and the sliding contact surface 33c of the third housing is the radius of the friction spring 51, the elastic force of the friction spring 51, the mass of the weight 55, and the weight 55 from the center of the ratchet wheel 40. It is determined by the radius and the like, and can be arbitrarily set by the designer according to the specifications of the seat belt retractor 1.

Further, in the ring-shaped friction spring 51, as shown in FIGS. 5 to 7, the spring wire 52 may be double-wound. The cross-sectional shape of the spring wire rod 52 may be a circular shape shown in FIG. 5, or a rectangular shape in which the ridge line portion (corner portion) 52a shown in FIG. 6 is R-chamfered, and the ridge line portion (corner portion) shown in FIG. The corner portion) 52a may be a rectangle without R chamfering. However, by using the friction spring 51 in which the spring wire 52 having a rectangular cross section shown in FIGS. 6 and 7 is double-wound, the planes come into contact with each other when the friction spring 51 is expanded or contracted, and its operation is stable. To do.

Further, a central portion of the crank-shaped lock arm 60 is swingably mounted on the arm support shaft portion 33b provided in the third housing 33. The lock arm 60 has a claw portion 62 engaged with the ratchet tooth portion 43 at the tip thereof, and is selectively switched and displaced between the lock position and the unlock position by the electromagnetic solenoid 70.

In this case, when the base end 63 of the lock arm 60 is connected to the plunger 71 of the electromagnetic solenoid 70 and the electromagnetic solenoid 70 is in a non-energized state (when OFF) by the urging force of the return spring 72 arranged on the plunger 71, The lock arm 60 is held at an unlocked position (a position where the claw portion 62 of the lock arm 60 is separated from the ratchet tooth portion 43 of the ratchet wheel 40). Further, when the electromagnetic solenoid 70 is switched to the energized state (when ON), the plunger 71 is pulled in against the urging force of the return spring 72, so that the lock arm 60 is moved from the unlocked position to the locked position (lock arm 60). The claw portion 62 of the ratchet wheel 40 is displaced to the position where it engages with the ratchet tooth portion 43 of the ratchet wheel 40).

The claw portion 62 of the lock arm 60 faces the ratchet tooth portion 43 of the ratchet wheel 40. When the lock arm 60 is operated to the locked position, the claw portion 62 of the lock arm 60 engages with the ratchet tooth portion 43 of the ratchet wheel 40. In the engaged state, the claw portion 62 of the lock arm 60 allows only the rotation of the ratchet wheel 40 in the belt pulling direction RB and prevents the rotation of the belt winding direction RA. That is, the claw portion 62 of the lock arm 60 and the ratchet tooth portion 43 of the ratchet wheel 40 constitute a one-way clutch that allows rotation of only the belt pull-out direction RB of the ratchet wheel 40.

The lock arm 60 and the electromagnetic solenoid 70 set the state of the ratchet wheel 40 as a regulated state (TRD = ON state) in which the rotation of the ratchet wheel 40 in the belt pull-out direction RB is permitted and the rotation of the belt winding direction RA is regulated. , A switching device 80 that selectively switches between a release state (TRD = OFF state) that allows rotation of the ratchet wheel 40 in both the belt pull-out direction RB and the belt winding direction RA is configured.

That is, when the lock arm 60 was switched to the unlocked position, the electromagnetic solenoid 70 enabled the transmission of the urging force of the belt winding direction RA by the secondary spring 22 to the spindle 10 and switched the lock arm 60 to the locked position. At this time, the transmission of the urging force of the belt winding direction RA by the auxiliary spring 22 to the spindle 10 is invalidated.

Further, the electromagnetic solenoid 70 holds TRD = OFF, that is, the lock arm 60 in the unlocked position when the tongue of the webbing B (not shown) is locked to the buckle, and the tongue of the webbing B is locked to the buckle. When, TRD = ON, that is, the lock arm 60 is held in the locked position. This changeover signal is emitted in response to a detection signal of a detection switch (not shown) built in the buckle. That is, when the tongue is inserted into the buckle and engaged, an energization signal (ON signal) is supplied to the electromagnetic solenoid 70 so that TRD = ON, and when the tongue is not inserted into the buckle or the engagement is disengaged. At that time, a non-energized signal (OFF signal) is supplied to the electromagnetic solenoid 70 so that TRD = OFF.

Next, the operation of the seatbelt retractor will be described with reference to FIGS. 8 to 13. 8 to 12 are schematic views of the seatbelt retractor in each usage situation.

First, as shown in FIG. 8, when the tongue of the webbing B is not engaged with the buckle, TRD = OFF and the ratchet wheel 40 is not restrained at all (rotation is not regulated), so that the spindle 10 is used. The combined urging force FA + FB by the main spring 21 and the sub spring 22 acts on the.

The memory member 23 is arranged in series with the sub-spring 22 via the cover 48 and the ratchet wheel 40, has the same swirling direction as the sub-spring 22, and is completely wound in a free state. Therefore, in the state of TRD = OFF, the memory member 23 is kept in a completely wound state, and the ratchet wheel 40 and the retainer 12 rotate integrally. Therefore, in the state of TRD = OFF, the urging force FB of the sub spring 22 is added to the urging force FA of the main spring 21 and acts on the spindle 10. Further, when the rotation of the ratchet wheel 40 and the cover 48 is stopped, the friction spring 51 is provided with a gap C away from the sliding surface 33c of the third housing, and the friction spring 51 and the third housing are separated from each other. The sliding resistance with the sliding surface 33c does not act on the ratchet wheel 40.

Therefore, when the webbing B is pulled out or wound in this situation, a large combined urging force FA + FB by the main spring 21 and the sub spring 22 acts in the belt winding direction. When the occupant pulls out the webbing B against the combined urging force FA + FB of the main spring 21 and the sub spring 22, the spindle 10 rotates in the belt pulling direction (arrow RB direction) to pull the main spring 21 and the sub spring 22. The main spring 21 and the sub spring 22 store energy while the memory member 23 is kept completely wound (the memory member 23 is wound and tightened). Further, when winding the webbing B, the spindle 10 can be quickly rotated by the combined urging force FA + FB of the main spring 21 and the sub spring 22.

When the spindle 10 rotates by pulling out or winding the webbing B, the retainer 12 and the ratchet wheel 40 also rotate, but since the rotation speed is slow, the friction spring 51 is separated from the sliding surface 33c of the third housing. To maintain. Therefore, even when the webbing B is pulled out or wound up, the resistance force due to the sliding resistance between the friction spring 51 and the sliding surface 33c of the third housing does not act on the ratchet wheel 40.

Next, when the occupant inserts the pulled out webbing B tongue into the buckle and engages it, an ON signal is output from the buckle detection switch, and as shown in FIG. 9, the electromagnetic solenoid 70 is turned on and the electromagnetic solenoid 70 is turned on. Pulls in the plunger 71 against the urging force of the return spring 72 to move the lock arm 60. As a result, the claw portion 62 of the lock arm 60 engages with the ratchet tooth portion 43 of the ratchet wheel 40, and the ratchet wheel 40 is restricted from rotating in one direction in the belt winding direction (arrow RA direction). That is, this state is the state of TRD = ON (regulated state).

Then, when trying to return the webbing B in the belt winding direction (arrow RA direction) in order to take the slack of the webbing B from the state where the electromagnetic solenoid 70 is ON (TRD = ON), as shown in FIG. 10, the ratchet wheel Since the rotation of 40 is restricted in the belt winding direction, the transmission of the urging force FB of the auxiliary spring 22 to the spindle 10 is invalidated.

Further, when the webbing B is rewound in the belt winding direction, the retainer 12 to which the inner end portion 23b of the memory member 23 is locked rotates integrally with the spindle 10, and the winding starts to loosen. That is, the memory member 23 is unwound by the rotation of the spindle 10 in the winding direction from the completely wound state. Therefore, the urging force acting on the spindle 10 in the belt winding direction in the state of TRD = ON is only the urging force FA in the belt winding direction of the main spring 21. This state corresponds to a state in which the webbing B is rewound to a position where the occupant fits.

When the webbing B is rewound in the belt winding direction in this TRD = ON state, the ratchet wheel 40 is prevented from rotating because the claw portion 62 of the lock arm 60 engages with the ratchet tooth portion 43. The gap C between the friction spring 51 and the sliding surface 33c of the third housing is maintained. Further, when the webbing B is pulled out in the state of TRD = ON, the cover 48 rotates together with the ratchet wheel 40, but since the rotation speed is slow, between the friction spring 51 and the sliding surface 33c of the third housing. Has a gap C. Therefore, the braking force of the friction spring 51 does not act in either the winding or the drawing of the webbing B.

The urging force acting on the spindle 10 during winding and rewinding of the webbing B in the state of TRD = ON is such that the urging force FB of the sub spring 22 is invalidated and the belt winding direction of the main spring 21 is applied. Since it is a power FA, if the urging force FB of the sub spring 22 is set larger than the urging force FA of the main spring 21 (FB> FA), the webbing B is wound when TRD = ON and TRD = OFF. The difference in force can be set large.

Therefore, the occupant is restrained by a force weaker than the force when the tongue is inserted and engaged with the buckle, the occupant's feeling of oppression is reduced, and the feeling of freedom is increased. In this way, the difference in winding force between when TRD = OFF (when winding and pulling out for seatbelt attachment) and when TRD = ON (when seatbelt is normally attached) can be set to a large extent. As a result, the comfort of the occupant when wearing the belt can be improved.

Next, as shown in FIG. 11, when the tongue of the webbing B is pulled out from the buckle, the electromagnetic solenoid 70 is switched to OFF in response to the OFF signal of the detection switch in the buckle. As a result, the plunger 71 returns to the protruding position by the urging force of the return spring 72, the lock arm 60 rotates, and the ratchet tooth portion 43 of the ratchet wheel 40 and the claw portion 62 of the lock arm 60 are disengaged.

As a result, the ratchet wheel 40 is rapidly rotated with respect to the retainer 12 by the urging force FB of the auxiliary spring 22. At the same time, the urging force FB of the auxiliary spring 22 acting on the ratchet wheel 40 is transmitted to the memory member 23, and the memory member 23 tries to return to the wound shape.

At this time, as shown in FIG. 4, the cover 48 integrally assembled with the ratchet wheel 40 and the friction spring 51 rotate rapidly. Then, the diameter of the friction spring 51 is expanded by the centrifugal force acting on the weight 55 fixed to the other end 54 of the friction spring 51. Then, when the rotation speed becomes faster than the predetermined rotation speed, the friction spring 51 slides into contact with the sliding surface 33c of the third housing, and the sliding resistance between the friction spring 51 and the sliding surface 33c of the third housing causes the ratchet wheel 40 to slide. The increase in rotation speed is suppressed.

When TRD = ON to TRD = OFF, the urging force FB of the sub-spring 22 is transmitted to the memory member 23 via the ratchet wheel 40, and the unwound memory member 23 is wound.

FIG. 13 is a graph showing a state in which an increase in the rotational speed of the ratchet wheel is suppressed by the sliding resistance between the friction spring and the sliding surface of the third housing. In the conventional seatbelt retractor without the friction spring 51, as shown by the curve S1, the rotation speed of the ratchet wheel 40 reaches a high speed of 8000 rpm 200 ms after TRD = OFF, and the memory member 23 is completely completed at a high speed. It is rolled up. For this reason, an unpleasant abnormal noise is generated due to the impact at the completion of winding.

On the other hand, in the seatbelt retractor 1 of the present embodiment including the friction spring 51 shown by the curve S2, when the ratchet wheel 40 rotates in the direction in which the memory member 23 is wound, the friction spring 51 and the sliding surface 33c of the third housing A braking force acts on the ratchet wheel 40 due to the sliding resistance of the ratchet wheel 40, TRD = OFF, and the rotation speed after 200 ms has elapsed is suppressed to 3000 rpm, so that the memory member 23 is not wound at once. As a result, the generation of abnormal noise due to the winding of the memory member 23 is suppressed, and the discomfort given to the occupant is significantly reduced.

Then, as shown in FIG. 12, when the memory member 23 is completely wound, the rotation of the ratchet wheel 40 slows down to the same rotation speed as the retainer 12 (spindle 10) when winding the webbing B. .. When the rotation speed of the ratchet wheel 40 becomes equal to or lower than a predetermined rotation speed, the centrifugal force acting on the weight 55 decreases, the friction spring 51 shrinks in diameter, and the sliding surface of the friction spring 51 and the third housing The sliding contact with 33c is automatically released, and the original state shown in FIG. 8 is restored.

When the occupant pulls out the webbing B further while the tongue of the webbing B is inserted into and engaged with the buckle in the state of TRD = ON shown in FIG. 9, or after the occupant normally wears the belt. The webbing B may be pulled out beyond the pull-out position of the webbing B, such as when the vehicle takes a large forward leaning posture or when the vehicle is turned back greatly to back the vehicle. In this case, as shown in FIG. 9, with the memory member 23 completely wound, the ratchet wheel 40 whose rotation is not restricted in the belt withdrawal direction rotates in the belt withdrawal direction while winding the auxiliary spring 22. .. At this time, since the claw portion 62 and the ratchet tooth portion 43 form a one-way clutch, the lock arm 60 rotates in a direction away from the ratchet tooth portion 43 of the ratchet wheel 40, which hinders the withdrawal of the webbing B. There is no.

The winding force acting on the spindle 10 at this time is a combined urging force FA + FB of the urging force FA in the belt winding direction of the main spring 21 and the urging force FB in the belt winding direction of the sub spring 22.

Therefore, the ratchet wheel 40 is restricted from rotating in a state where the meshing position of the ratchet tooth portion 43 with the claw portion 62 of the lock arm 60 is changed. Even in this case, the webbing B is rewound in the belt winding direction from the meshing position of the updated lock arm 60 and the ratchet wheel 40, so that the urging force FA in the belt winding direction of the main spring 21 acts on the spindle 10. ..

As described above, according to the seat belt retractor 1 of the present embodiment, the spindle 10 and the main spring 21 that constantly applies an urging force in the belt winding direction to the spindle 10 are arranged in parallel with the main spring 21. A ratchet wheel 40, which is connected to an auxiliary spring 22 that selectively applies an urging force in the belt winding direction to the spindle 10 and an inner end portion 22b of the auxiliary spring 22 and has a plurality of ratchet tooth portions 43, A retainer 12 that is integrally rotatably fixed to the spindle 10 and into which the ratchet wheel 40 fits, a switching device 80 that selectively switches the ratchet wheel 40 between the regulated state and the released state, and a spindle 10 with respect to the ratchet wheel 40 in the regulated state. A memory member 23 for storing the relative rotation amount of the wheelchet wheel is provided. Further, the seatbelt retractor 1 includes a ring-shaped friction spring 51 whose one end 53 is fixed to a cover 48 which rotates together with the ratchet wheel 40 and whose other end 54 is a free end. Then, when the restricted state by the switching device 80 is released and the ratchet wheel 40 rotates at high speed together with the friction spring 51, the friction spring 51 expands in diameter as the ratchet wheel 40 rotates, and the friction spring 51 becomes the third housing. A braking force is applied to the ratchet wheel 40 by the sliding contact with the sliding surface 33c of the ratchet wheel 40 and the frictional force between the friction spring 51 and the sliding surface 33c of the third housing. As a result, the memory member 23 is not suddenly wound when the tension reducer is released, and unpleasant abnormal noise generated from the memory member 23 can be reduced. Further, the load acting on the memory member 23 when the winding of the memory member 23 is completed is reduced, and the durability is improved.

Further, a weight 55 is fixed to the other end 54 of the friction spring 51, and when the restricted state of the ratchet wheel 40 by the switching device 80 is released, the friction spring is caused by the centrifugal force acting on the weight 55 due to the rotation of the ratchet wheel 40. 51 expands in diameter. Therefore, by using the weight 55, the diameter of the friction spring 51 can be reliably increased.

Further, one end 53 of the friction spring 51 is attached to the ratchet wheel 40 and is fixed to the side surface of the cover 48 accommodating the memory member 23 in cooperation with the ratchet wheel 40. Therefore, the memory member when the tension reducer is released. A mechanism that reduces abnormal noise due to winding of 23 can be designed compactly.

The present invention is not limited to the above embodiment, and can be appropriately modified, improved, and the like. For example, in the above embodiment, the memory member 23 has been described as a long tape in which a resin such as polyamide (PA6) is stretched, but the memory member of the present invention may be a long strip-shaped member. It can also be configured with a spiral spring or the like. In this case as well, by applying a braking force to the ratchet wheel, it is possible to soften the contact between the members constituting the memory means, and the same effect as that of the present embodiment can be obtained.

Further, in the above embodiment, by fixing the weight 55 to the other end 54 of the friction spring 51, the friction spring 51 is surely expanded in diameter by the centrifugal force acting on the weight 55 when the ratchet wheel 40 rotates at high speed. I'm letting you. However, the friction spring 51 of the present invention may be configured without using the weight 55 separately, and the friction spring 51 may be expanded in diameter by the centrifugal force acting on the friction spring 51 itself.

Further, in the above embodiment, the memory member 23 is used as the rotation memory mechanism for storing the relative rotation amount of the spindle 10 with respect to the ratchet wheel 40 in the regulated state, but the seatbelt retractor of the present invention is not limited to this. That is, as the rotary memory mechanism, a Geneva mechanism or a wobble gear mechanism can also be applied. For example, as shown in FIGS. 14 and 15, the wobble gear mechanism as the rotation memory mechanism has an internal tooth portion 49 formed on the inner peripheral portion of the ratchet wheel 40 and an eccentric shaft eccentric with respect to the axial center of the spindle 10. The ratchet is provided with a wobble gear 90 which is rotatably provided in the ratchet, has a number of teeth different from the number of teeth of the internal tooth portion 49, and has an external tooth portion 93 which meshes with the internal tooth portion 49 of the ratchet wheel 40 on the outer peripheral portion. The inner tooth portion 49 of the wheel 40 and the outer tooth portion 93 of the wobble gear 90 are formed by a helical gear.

Further, the wobble gear mechanism includes a stopper 47 formed at a predetermined position in the circumferential direction on the inner diameter side of the internal tooth portion 49 of the ratchet wheel 40, and a protrusion 97 formed on the side surface of the wobble gear 90 on the ratchet wheel side. A contact member 98 that has a fitting hole 98a that fits with the protrusion 97 so as to be movable with respect to the protrusion 97, and is in contact with the stopper 47 in the released state and can be separated from the stopper 47 in the regulated state. And further prepare.

Then, after the ratchet wheel 40 rotates in the belt withdrawal direction, when the restricted state in which the rotation in the belt winding direction is restricted is released, the wobble gear 90 rotates in the belt winding direction due to the urging force of the auxiliary spring 22. The impact force generated when the contact member 98 comes into contact with the stopper 47 is absorbed by the friction spring 51 and the sliding surface 33c of the third housing 33 described above.

Further, in the above embodiment, when the tongue of the webbing B is inserted and engaged with the buckle, the electromagnetic solenoid 70 is operated by the detection signal sent from the detection switch of the buckle to operate the electromagnetic solenoid 70 in the TRD = OFF state and the TRD = ON state. However, the TRD state switching signal may be used to operate the electromagnetic solenoid 70 by a detection signal corresponding to the opening / closing of the door. In this case, the TRD = ON state is set by the detection signal when the door is closed, and the TRD = OFF state is switched by the detection signal when the door is opened.

Further, in the above embodiment, the friction spring 51 is attached to the cover 48 that rotates together with the ratchet wheel 40, but may be attached to the ratchet wheel 40.

1 Seatbelt retractor 2 Winding mechanism 10 Spindle 21 Main spring 21a Outer end 21b Inner end 22 Sub spring 22a Outer end 22b Inner end 23 Memory member (rotary memory mechanism, strip-shaped member)
23a Outer end 23b Inner end 31 First housing (fixed side member)
32 Second housing (fixed side member)
33 Third housing (fixed side member)
33c Sliding contact surface 40 Ratchet wheel 43 Ratchet tooth 48 Cover (member that rotates with the ratchet wheel)
51 Friction spring 53 One end 54 The other end (free end)
55 Weight 62 Claw 80 Switching device B Webbing (seat belt)

Claims (1)

A spindle on which the seat belt can be wound and pulled out,
A main spring composed of a spiral spring whose inner end is connected to the spindle and whose outer end is connected to a fixed side member to constantly apply an urging force in the belt winding direction to the spindle.
A secondary spring composed of a spiral spring, which is arranged in parallel with the main spring and whose outer end is connected to the fixed side member to selectively apply an urging force in the belt winding direction to the spindle. When,
A ratchet wheel to which the inner end portion of the sub-spring is connected, is rotatably provided coaxially with the spindle, and has a plurality of ratchet teeth on the outer peripheral portion.
A regulated state in which the ratchet wheel is provided with a claw portion that can be engaged with the ratchet tooth portion, the ratchet wheel is allowed to rotate in the belt pull-out direction, and the rotation in the belt winding direction is regulated, and the belt pull-out direction of the ratchet wheel. And a switching device that selectively switches between a release state that allows rotation in both directions of the belt winding direction, and
A rotation memory mechanism that stores the relative rotation amount of the spindle with respect to the ratchet wheel in the regulated state, and
It is a seatbelt retractor equipped with
The rotary memory mechanism is configured by spirally winding a long strip-shaped member, is arranged in series with the sub-spring, its inner end is connected to the spindle, and its outer end is said. It is a memory member connected to the ratchet wheel.
Wherein mounted on the ratchet wheel rotates with the previous SL ratchet wheel, one end portion on the side surface of the cover for accommodating the memory member in cooperation with said ratchet wheel is fixed, the ring and the other end portion is a free end Equipped with a friction spring
The arcuate portion of the friction spring has a substantially L-shaped cross section extending outward in the radial direction after protruding from the circular substrate in the axial direction of the spindle on the outer peripheral side of the circular substrate of the cover. It is mounted on the outer peripheral side of a plurality of spring accommodating portions provided apart from each other in the circumferential direction.
A weight is fixed to the other end of the friction spring so as to be closer to the inner diameter than the outer peripheral surface of the friction spring.
When the restricted state of the ratchet wheel is released by the switching device, the friction spring expands in diameter due to the centrifugal force acting on the weight due to the rotation of the ratchet wheel, so that the friction spring slides on the fixed side member. A seat belt retractor which is in contact with the ratchet wheel and applies a braking force to the ratchet wheel by a frictional force between the friction spring and the fixed side member.