JP7412894B2 - Seatbelt retractor and seatbelt device - Google Patents

Description

The present invention relates to a seat belt retractor and a seat belt device.

Seatbelt devices installed in vehicles such as automobiles are used to restrain occupants with seatbelts in the event of an emergency (for example, when a large deceleration is applied to the vehicle during a collision while the seatbelt is worn). Prevents passengers from jumping out of their seats.

Such a seatbelt device is equipped with a seatbelt retractor that retracts and retracts the seatbelt. In this seat belt retractor, the seat belt is wound around the spool when the seat belt is not worn, but when it is worn, it is pulled out and worn by the occupant. In the event of an emergency as described above, the locking means of the seat belt retractor is activated to prevent the rotation of the spool in the belt pulling direction, thereby preventing the seat belt from being pulled out, so that the occupant is not restrained by the seat belt in an emergency. Ru.

When an occupant is restrained by a seat belt in an emergency such as a vehicle collision, large vehicle deceleration occurs, and the occupant attempts to move forward due to large inertia. Therefore, a large load is applied to the seat belt, and the occupant receives a large force from the seat belt. Although this force is not a particular problem for the occupant, it is desirable to limit it if possible.

Therefore, the development of a seatbelt retractor equipped with an energy absorption mechanism (hereinafter also referred to as an EA mechanism) that limits the load acting on the seatbelt and absorbs and alleviates the occupant's energy in the event of an emergency while the seatbelt is being worn is progressing. . As one such seatbelt retractor, there is a retractor equipped with a mechanical EA mechanism that utilizes the force generated by the twisting of a torsion bar and an electric EA mechanism that utilizes the force generated by an electrical short circuit of the motor. (For example, see Patent Document 1).

Japanese Patent Application Publication No. 2001-270423

However, in the conventional technology, if the load generated by the motor becomes excessive for some reason such as a failure, there is a risk that an unintended excessive load will act on the seat belt.

Therefore, the present disclosure provides a seatbelt retractor and a seatbelt device that can prevent excessive loads from acting on the seatbelt.

This disclosure:
A spool for winding up the seat belt,
a locking mechanism that allows rotation of the spool when inactive and prevents rotation of the spool in a direction in which the seat belt is pulled out when activated;
The spool is provided between the spool and the locking mechanism, and when the spool is prevented from rotating by the locking mechanism, the spool is deformed by the rotational force of the seat belt due to the pull-out load, and the kinetic energy of the occupant is absorbed. a first energy absorption mechanism that absorbs
motor and
a deceleration mechanism that decelerates the power of the motor and transmits it to the spool ;
provided in the speed reduction mechanism, and after the spool is rotated in the winding direction of the seat belt by the motor in an emergency, when the lock mechanism is activated to prevent rotation of the spool; a second energy absorption mechanism that is deformed by the rotational force of the spool due to the pull-out load of the seat belt and absorbs the kinetic energy of the occupant ;
Provides a seatbelt retractor with Further, the present disclosure provides a seat belt device including the seat belt retractor.

According to the technology of the present disclosure, it is possible to provide a seatbelt retractor and a seatbelt device that can prevent excessive loads from acting on the seatbelt.

FIG. 1 is a diagram illustrating the configuration of a seat belt device in one embodiment. FIG. 2 is a block diagram illustrating the configuration of a seatbelt retractor in one embodiment. It is a figure which illustrates the behavior of a limit load with respect to the stroke of a spool. It is a front view of the seatbelt retractor in a 1st embodiment. It is a right view of the seatbelt retractor in a 1st embodiment. It is a left side view of the seatbelt retractor in a 1st embodiment. FIG. 6 is a diagram showing a cut surface of the seat belt retractor in the first embodiment along arrow AA (see FIG. 6). It is an exploded perspective view of the seatbelt retractor in a 1st embodiment. FIG. 3 is a side view of the clutch. FIG. 3 is an exploded perspective view of the clutch. 9 is a diagram showing an off state of the clutch (clutch pawl closed state) along arrow BB (see FIG. 9). FIG. FIG. 9 is a diagram showing the clutch on operation (clutch pawl open state) along arrow BB (see FIG. 9). It is a front view of the seatbelt retractor in 2nd Embodiment. It is a right view of the seatbelt retractor in 2nd Embodiment. It is a left side view of the seatbelt retractor in 2nd Embodiment. FIG. 16 is a diagram showing a cut surface of the seat belt retractor in the second embodiment along arrow CC (see FIG. 15). It is an exploded perspective view of the seatbelt retractor in a 2nd embodiment. FIG. 3 is a perspective view of the first plate holding gear. FIG. 3 is a perspective view of the second plate holding gear. It is a figure showing the state before operation of an EA plate. It is a figure which shows the state in which an EA plate is in operation.

Embodiments according to the present disclosure will be described below with reference to the drawings.

FIG. 1 is a diagram illustrating the configuration of a seat belt device according to an embodiment of the present disclosure. A seat belt device 101 shown in FIG. 1 is an example of a seat belt device mounted on a vehicle. The seat belt device 101 includes, for example, a seat belt 104, a retractor 103, a shoulder anchor 106, a tongue 107, and a buckle 108.

The seat belt 104 is an example of a seat belt that restrains the occupant 111 sitting on the seat 102 of the vehicle, and is a belt-shaped member that is retractably wound around the retractor 103. Seat belts are also called webbing. A belt anchor 105 at the tip of the seat belt 104 is fixed to the seat 102 or the vehicle body near the seat 102.

The retractor 103 is an example of a seat belt retractor that allows the seat belt 104 to be retracted or pulled out. The retractor 103 restricts the seat belt 104 from being pulled out from the retractor 103 when acceleration/deceleration or vehicle angle equal to or greater than a predetermined value is detected, such as during a vehicle collision. The retractor 103 is fixed to the seat 102 or the vehicle body near the seat 102. Retractor 103 is an example of a seatbelt retractor.

The retractor 103 has a function of retracting the seat belt 104 onto a spool using the power of a motor 103a. For example, before a vehicle collision, the retractor 103 operates a motor 103a based on a signal from a sensor such as a millimeter wave radar, retracts the seatbelt 104 onto a spool, applies pretension to the seatbelt 104, and tightens the seatbelt 104. to quickly restrain the occupants. Further, the retractor 103 operates the motor 103a to retract the seat belt 104 with a spool, for example, when the tongue 107 and the buckle 108 are disconnected. For example, the retractor 103 operates a motor 103a to adjust the tension of the seatbelt 104 according to the driving situation (vehicle condition), thereby increasing the restraint of the occupant by the seatbelt 104 and the comfort when wearing the seatbelt 104. improve each other's abilities.

The state of the vehicle includes, for example, whether or not the seat belt 104 is pulled out, whether or not the occupant 111 is present, the traveling speed of the vehicle, the acceleration of the vehicle, steering operation, accelerator operation, brake operation, buckle 108 operation, door operation, and occupant operation. This refers to the state that represents the possible operation input of a selection switch onboard the vehicle.

The shoulder anchor 106 is an example of a belt insertion tool through which the seat belt 104 is inserted, and is a member that guides the seat belt 104 pulled out from the retractor 103 toward the shoulder of the occupant 111. The shoulder anchor 106 is fixed to the seat 102 or the vehicle body near the seat 102.

The tongue 107 is an example of a belt insertion tool through which the seat belt 104 is inserted, and is a component slidably attached to the seat belt 104 guided by the shoulder anchor 106.

The buckle 108 is a component into which a planar locking portion of a tongue 107 attached to the seat belt 104 is inserted and removed, and the tongue 107 is removably connected thereto. The buckle 108 is, for example, fixed to the seat 102 or the vehicle body near the seat 102.

With the tongue 107 connected to the buckle 108, the portion of the seat belt 104 between the shoulder anchor 106 and the tongue 107 is a shoulder belt portion 109 that restrains the chest and shoulders of the occupant 111. With the tongue 107 connected to the buckle 108, the portion of the seat belt 104 between the belt anchor 105 and the tongue 107 is a lap belt portion 110 that restrains the waist of the occupant 111.

FIG. 2 is a block diagram illustrating the configuration of a seat belt retractor in an embodiment according to the present disclosure. The retractor 1 and motor 12 shown in FIG. 2 correspond to the retractor 103 and motor 103a shown in FIG. 1, respectively. The retractor 1 is a seatbelt retractor that includes at least a spool 4, a lock mechanism 6, a first EA mechanism 53, a power transmission mechanism 21, and a second EA mechanism 54.

The spool 4 is a member that is rotatably supported by a frame (not shown) and retracts the seat belt 104 so that it can be pulled out.

The locking mechanism 6 allows the spool 4 to rotate when it is not in operation, and prevents the spool 4 from rotating in the direction in which the seat belt 104 is pulled out when it is in operation. The locking mechanism 6 prevents rotation of the spool 4 in the direction in which the seat belt 104 is pulled out by locking the first EA mechanism 53 when activated.

The first EA mechanism 53 is deformed by the rotation of the spool 4 in the direction in which the seat belt 104 is pulled out and the lock mechanism 6 blocking the rotation. The first EA mechanism 53 is an example of a first energy absorption mechanism that absorbs and relieves occupant energy by limiting the load acting on the seat belt.

For example, in an emergency such as a vehicle collision, the seat belt 104 is strongly wound around the spool 4 by rotating the spool 4 in the belt winding direction by operating at least one of the pretensioner 8 and the motor 12. Thereafter, as the occupant moves forward due to inertia, the seat belt 104 attempts to be pulled out from the spool 4. At this time, since the first EA mechanism 53 is locked by the operation of the lock mechanism 6, rotation of the spool 4 in the direction of belt withdrawal is prevented. However, since the spool 4 attempts to rotate in the direction in which the seat belt 104 is pulled out, the first EA mechanism 53 is deformed due to the rotation of the spool 4 in the direction in which the seat belt 104 is pulled out and the lock mechanism 6 prevents the rotation. The deformation of the first EA mechanism 53 limits the load acting on the seat belt 104 pulled out from the spool 4. In other words, the energy of the occupant is absorbed and relaxed by the deformation of the first EA mechanism 53.

The power transmission mechanism 21 combines a first load (hereinafter also referred to as base load BN) generated by the deformation of the first EA mechanism 53 with a second load (hereinafter referred to as assist load AN) generated by the motor 12 and the speed reduction mechanism. ) is added. The number of deceleration mechanisms that decelerate and transmit the rotation of the output shaft of the motor 12 may be one or more. FIG. 2 shows a first speed reduction mechanism 51 and a second speed reduction mechanism 52. By adding the assist load AN to the base load BN, a limit load (hereinafter also referred to as limit load LN) is generated. The retractor 1 limits the load acting on the seat belt 104 with the limit load LN generated in this way.

The second EA mechanism 54 limits the increase in the limit load LN generated by adding the assist load AN to the base load BN by deforming itself. Therefore, even if the assist load AN generated by the motor 12 and the speed reduction mechanism becomes excessive for some reason such as a failure, the increase in the limit load LN is limited by the deformation of the second EA mechanism 54. Therefore, excessive load can be prevented from acting on the seat belt 104. Note that the second EA mechanism 54 is an example of a second energy absorption mechanism that absorbs and relieves occupant energy by limiting the load acting on the seat belt.

FIG. 3 is a diagram illustrating the behavior of the limit load LN with respect to the stroke of the spool 4. The horizontal axis represents the relative rotation amount (stroke) of the spool 4 in the belt withdrawal direction after the locking by the locking mechanism 6 is activated, and the vertical axis represents the limit load LN generated by the retractor 1.

As shown in FIG. 3, the power transmission mechanism 21 increases the limit load LN by adding the assist load AN generated by the motor 12 and the reduction mechanism to the base load BN generated by the deformation of the first EA mechanism 53. generate. The limit load LN is approximately equal to the sum of the base load BN and the assist load AN.

In a state where the limit load LN has not reached the upper limit load Lb, the assist load AN is directly added to the base load BN. The upper limit load Lb is determined by adding the first limit load N1 by the first EA mechanism 53 and the second limit load N2 by the second EA mechanism 54. The first limit load N1 is the maximum load that can be generated by deforming the first EA mechanism 53, and the second limit load N2 can be generated by deforming the second EA mechanism 54. This is the maximum load. On the other hand, even if the limit load LN becomes excessive for some reason, it is limited so as not to exceed the upper limit load Lb, as shown in waveform c, so that an excessive load is prevented from acting on the seat belt 104. can.

Furthermore, even if the assist load AN cannot be added to the base load BN due to some abnormality due to a vehicle collision (for example, a failure of the power transmission mechanism 21), the limit load LN can be changed to the first EA mechanism 53. The limit load N1 can be limited to an upper limit. In other words, since the load acting on the seat belt 104 can be limited by the first limit load N1 by the first EA mechanism 53, even in abnormal situations where the assist load AN cannot be applied, excessive load can be prevented from acting on the seat belt 104. It can be prevented.

Further, the retractor 1 includes a control unit 10 (see FIG. 2) that adjusts the assist load AN by controlling the motor 12, so that the limit load LN can be flexibly adjusted within a range below the upper limit load Lb.

For example, the control unit 10 can adjust the rise speed of the limit load LN by adjusting the rise speed of the assist load AN by controlling the motor 12, as shown by waveforms d and e in FIG. Waveform d shows the case where the motor 12 is controlled so that the rising speed of the assist load AN becomes faster, and waveform e shows the case where the motor 12 is controlled so that the rising speed of the assist load AN becomes slower.

Further, for example, the control unit 10 may increase or decrease the positive assist load AN added to the base load BN by controlling the motor 12. Thereby, as shown by waveforms f, g, and h in FIG. 3, the limit load LN can be increased or decreased within the range from the first limit load N1 to the upper limit load Lb. Furthermore, the control unit 10 can adjust the limit load LN to the first limit load N1 by stopping the motor 12 and reducing the assist load AN to zero. Further, the control unit 10 can adjust the limit load LN to be lower than the first limit load N1 by controlling the motor 12 so that a negative assist load AN is added to the base load BN. For example, the control unit 10 can increase or decrease the limit load LN within a range lower than the first limit load N1 by increasing or decreasing the negative assist load AN added to the base load BN by controlling the motor 12.

In this way, the control unit 10 can generate a flexible limit load LN within the range below the upper limit load Lb by controlling the motor 12. Therefore, for example, the control unit 10 can generate an appropriate limit load LN depending on the collision conditions and the physique of the occupant.

Next, the configuration shown in FIG. 2 will be described in more detail.

Preferably, the motor 12 and the spool 4 are connected to each other via a second EA mechanism 54 . As a result, the power of the motor 12 is transmitted to the spool 4 via the second EA mechanism 54, so the magnitude of the assist load AN is accurately limited to below the second limit load N2 by the second EA mechanism 54. can.

In the configuration shown in FIG. 2, the speed reduction mechanism that reduces and transmits the rotation of the rotating shaft of the motor 12 is a first speed reduction mechanism 51 and a second speed reduction mechanism that are connected to each other via a second EA mechanism 54. 52. That is, the second EA mechanism 54 is inserted into the power transmission path between the first deceleration mechanism 51 and the second deceleration mechanism 52. By connecting the second EA mechanism 54 and the spool 4 via the second reduction mechanism 52, the second EA mechanism 54 can reduce the Since the second limit load N2 can be set small, the second EA mechanism 54 can be made smaller.

For example, consider a case where the upper limit load Lb is set to 4 kN (kilonewtons). Assuming that the first limit load N1 by the first EA mechanism 53 is 1 kN, the second limit load N2 by the second EA mechanism 54 is 3 kN ( =Lb-N1). On the other hand, in the case where the connection is made via the second reduction mechanism 52, when the reduction ratio R of the second reduction mechanism 52 is set to 2, the second limit load N2 by the second EA mechanism 54 is set to 1. It is sufficient to set it to .5kN (=(Lb-N1)/R). Therefore, the second EA mechanism 54 can be made smaller in the case where the second EA mechanism 54 is connected via the second speed reduction mechanism 52, compared to the case where the second EA mechanism 54 is connected without the second speed reduction mechanism 52. For example, when the second EA mechanism 54 generates the second limit load N2 by deforming a torsion bar, the second EA mechanism 54 can be laid out inside the retractor 1 because the torsion bar can be made thinner. becomes easier.

The first deceleration mechanism 51 decelerates the rotation of the output shaft 12 a of the motor 12 and transmits it to the second EA mechanism 54 . The second deceleration mechanism 52 decelerates the rotation generated by the second EA mechanism 54 and transmits it to the spool 4 side.

Further, it is preferable that the power transmission mechanism 21 includes a clutch 25 that blocks transmission of force from the spool 4 to the motor 12 and allows transmission of force from the motor 12 to the spool 4. By providing the clutch 25 that interrupts the transmission of force from the spool 4 to the motor 12, it is possible to prevent, for example, the transmission of the enormous winding torque of the seat belt 104 by the pretensioner 8 to the motor 12 in the event of a collision. Furthermore, if the rotating shaft of the spool 4 and the output shaft of the motor 12 are connected, when the occupant pulls out the seat belt 104 from the retractor 1 or causes the retractor 1 to retract it, the load of the motor 12 is applied to the seat. This will be transmitted to the passenger operating the belt 104. As a result, the occupant cannot smoothly pull out or retract the seat belt 104, which may cause discomfort to the occupant. On the other hand, the clutch 25 is a one-way clutch that interrupts the transmission of the rotational force from the spool 4 to the motor 12 and transmits the rotational force from the motor 12 to the spool 4. Therefore, transmission of the rotational force from the spool 4 to the motor 12 is interrupted by the clutch 25, so that the occupant can smoothly pull out the seat belt 104 from the retractor 1 or wind it around the retractor 1.

The clutch 25 interrupts the transmission of force from the spool 4 to the output shaft 12a when the output shaft 12a of the motor 12 is not rotating, and transmits the force from the output shaft 12a to the spool 4 when the output shaft 12a is rotating. Allows the transmission of force to. Thereby, the control unit 10 operates the motor 12 to rotate the output shaft 12a, thereby turning on the clutch 25 (transmission of force from the output shaft 12a to the spool 4 can be allowed). On the other hand, by stopping the motor 12 and stopping the rotation of the output shaft 12a, the control unit 10 can turn off the clutch 25 (transmission of force from the spool 4 to the output shaft 12a can be interrupted). That is, the control unit 10 can turn on the clutch 25 in synchronization with the operation of adding the assist load AN.

In the form shown in FIG. 2, the first EA mechanism 53 has a first portion 55 that engages with the spool 4 and a second portion 56 that is locked by the locking mechanism 6. The power transmission mechanism 21 transmits the assist load AN to the first portion 55 side. By transmitting the assist load AN to the first portion 55 that engages with the spool 4, the assist load AN can be efficiently added to the base load BN.

Next, a specific configuration of the retractor 1 will be explained.

FIG. 4 is a front view of the seat belt retractor in the first embodiment. FIG. 5 is a right side view of the seat belt retractor in the first embodiment. FIG. 6 is a left side view of the seat belt retractor in the first embodiment. FIG. 7 is a diagram showing a cut surface of the seat belt retractor in the first embodiment along arrow AA (see FIG. 6). FIG. 8 is an exploded perspective view of the seat belt retractor in the first embodiment.

The retractor 1A shown in FIGS. 4 to 8 is an example of a seatbelt retractor, and is a specific example of the retractor 1 shown in FIG. The retractor 1A includes a first EA mechanism 53A, which is an example of the first EA mechanism 53, and a second EA mechanism 54A, which is an example of the second EA mechanism 54. The first EA mechanism 53A generates a base load BN by deforming the torsion bar 7 provided between the spool 4 and the lock mechanism 6. The second EA mechanism 54A limits the increase in the limit load LN by deforming the torsion bar 30 provided between the motor 12 and the spool 4. The torsion bar 7 is an example of a first EA member, and the torsion bar 30 is an example of a second EA member. The configuration of the retractor 1A will be described below with reference to FIGS. 4 to 8.

The retractor 1A includes a frame 2, a spool 4, a vehicle sensor 5, a lock mechanism 6, a torsion bar 7, a pretensioner 8, and a power transmission mechanism 21A.

The frame 2 is a housing that rotatably accommodates the spool 4 and forms the skeleton of the retractor 1A. The frame 2 includes, for example, a pair of opposing side surfaces 2b and 2c, and a back surface 2a that connects the side surfaces 2b and 2c. A locking mechanism 6 is disposed on the outside of the side surface portion 2b (that is, on the side opposite to the spool 4 with respect to the side surface portion 2b). The pair of side surfaces 2b and 2c each have a circular (including approximately circular) opening.

The spool 4 is a winding member that is rotatably supported concentrically (including substantially concentrically) with each opening of the pair of side surfaces 2 b and 2 c of the frame 2 and winds up the seat belt 104 .

The vehicle sensor 5 is an example of a detection mechanism that detects a change in vehicle behavior (specifically, a sudden change in acceleration, deceleration, or tilt of the vehicle that occurs due to a change in vehicle behavior). The vehicle sensor 5 includes, for example, a sphere that moves with the deceleration of the vehicle that occurs in an emergency, and a locking pawl that is activated by the movement of the sphere.

The lock mechanism 6 performs a locking operation to lock the rotation of the spool 4 in the direction in which the seat belt 104 is pulled out. The lock mechanism 6 includes a lock gear 14 and a locking base 17. The lock gear 14 is fitted into the tip 7a of the torsion bar 7 that protrudes outward from the side surface 2b of the frame 2 so as to be rotatable relative to the torsion bar 7. The tip portion 7a may be a separate member such as a shaft connected to the torsion bar 7 in the axial direction, or may be a part of the torsion bar 7 itself. The locking base 17 is integrally rotatably supported by a second torque transmitting section 16, which will be described later, and holds the pawl in a swingable manner. The locking base 17 is an example of a locking member, which rotates together with the spool 4 during normal operation, and prevents the spool 4 from rotating in the direction in which the seat belt 104 is pulled out during operation. Ratchet teeth 14a are formed on the outer periphery of the lock gear 14.

The lock gear 14 normally rotates together with the torsion bar 7. On the other hand, in the above-mentioned emergency, the spherical body of the vehicle sensor 5 is activated and the locking pawl engages with the ratchet tooth 14a. This prevents (locks) the rotation of the lock gear 14 in the direction in which the seat belt 104 is pulled out. When the rotation of the lock gear 14 is locked, relative rotation occurs between the locking base 17 and the lock gear 14, and the pawl provided on the locking base 17 rotates, and the rotated pawl is provided on the side surface 2b. The inner teeth 2ba are engaged with each other. As a result, the rotation of the locking base 17 is stopped, and the rotation of the spool 4 in the direction in which the seat belt 104 is pulled out is also prevented.

The torsion bar 7 is formed with a first torque transmitting portion 15 that engages with the spool 4 in a relatively non-rotatable manner, and a second torque transmitting portion 16 that engages with the locking base 17 in a relatively non-rotatable manner. These transmission parts are provided at locations separated from each other in the axial direction. The first torque transmitting portion 15 is an example of a first portion 55 (see FIG. 2) that engages with the spool 4. The second torque transmitting portion 16 is an example of a second portion 56 (see FIG. 2) that is locked by the locking mechanism 6.

The pretensioner 8 includes a rotating body 27 that rotates the spool 4 in the winding direction of the seat belt 104 when activated. Since a known configuration can be applied to the power generation unit that rotates the rotating body 27, illustration thereof is omitted. The pretensioner 8 operates at the beginning of an emergency to generate a reactive gas in the power generating section, and transmits the belt winding torque generated by the reactive gas to the spool 4 via the rotating body 27. As a result, the seat belt 104 is wound around the spool 4 by a predetermined amount at the beginning of an emergency. The rotating body 27 is connected to the end of the spool 4 so as to be rotatable together with the spool 4.

The rotating body 27 rotates the spool 4 in the winding direction of the seat belt 104 when the pretensioner 8 is activated. The rotating body 27 is also called a paddle wheel. The rotating body 27 is coaxially connected to the spool 4. The injection body pushed by the gas generated by the gas generator of the power generation unit contacts the outer peripheral portion 27a of the rotating body 27, thereby rotating the rotating body 27 in the winding direction of the seat belt 104. As a result, the spool 4 also rotates in the winding direction of the seat belt 104. In other words, the seat belt 104 is wound onto the spool 4.

The power transmission mechanism 21A is an example of the power transmission mechanism 21 shown in FIG. The power transmission mechanism 21A includes a motor 12, a retainer 28, a first deceleration mechanism 51A, a second EA mechanism 54A, a retainer 29, a second deceleration mechanism 52A, and a clutch 25. The rotating body 27 may be one element of the power transmission mechanism 21A.

The motor 12 generates power to rotate the spool 4. Motor 12 is fixed to retainer 28 .

The retainer 28 has a through hole 28a through which the output shaft 12a of the motor 12 passes, and a holding hole 28b that rotatably holds the first tip 30a of the torsion bar 30.

The first speed reduction mechanism 51A is an example of the first speed reduction mechanism 51 (see FIG. 2), and includes a motor gear 20 and a connection gear 22.

The motor gear 20 is attached to the output shaft 12a of the motor 12 so as to be rotatable therewith. The motor gear 20 has external teeth 20a and a shaft hole 20b into which the output shaft 12a is inserted.

The connect gear 22 has external teeth 22a that constantly mesh with the external teeth 20a of the motor gear 20, and a shaft hole 22b into which the first tip 30a is inserted so as to be rotatable together with the first tip 30a. The external teeth 22a have a greater number of teeth than the external teeth 20a. The connect gear 22 rotates around a first tip 30a that passes through the holding hole 28b of the retainer 28.

The second EA mechanism 54A has a torsion bar 30 that is an EA member. The torsion bar 30 has a first tip 30a and a second tip 30b on both sides in the axial direction.

The retainer 29 includes a holding hole 29d that rotatably holds the second tip 30b of the torsion bar 30, a boss 29a that rotatably holds the idle gear 26, and a holding hole 29c that rotatably holds the rotating body 27. and has.

The second speed reduction mechanism 52A is an example of the second speed reduction mechanism 52 (see FIG. 2), and includes a connect gear 32, an idle gear 26, and a drive gear 23. The second speed reduction mechanism 52A shares the clutch 25 and the drive gear 23.

The connect gear 32 has external teeth 32a that constantly mesh with the external teeth 26a of the idle gear 26, and a shaft hole 32b into which the second tip 30b is inserted so as to be rotatable together with the second tip 30b. The connect gear 32 rotates around a second tip 30b that passes through the holding hole 29d of the retainer 29.

The idle gear 26 has external teeth 26a that constantly mesh with both the external teeth 32a of the connect gear 32 and the external teeth 23a of the drive gear 23, and a shaft hole 26b into which the boss 29a is inserted.

The drive gear 23 has external teeth 23a having a larger number of teeth than the external teeth 26a of the idle gear 26, and a shaft hole 23b into which the tip end 7b of the torsion bar 7 is fitted so as to be relatively rotatable.

The clutch 25 is arranged coaxially with the rotation axis of the spool 4 (in this embodiment, the torsion bar 7), that is, located on the same axis as the rotation axis of the spool 4.

The clutch 25 includes a drive gear 23, a clutch outer 24, and a clutch pawl 41.

The drive gear 23 is rotatably supported by a distal end portion 7b coaxial with the rotating shaft of the spool 4, and rotates according to the rotation of the output shaft 12a of the motor 12. The tip portion 7b is inserted into the shaft hole 23b of the drive gear 23 and the shaft hole 24b of the clutch outer 24. The drive gear 23 has a larger outer diameter than the idle gear 26, and is formed with external teeth 23a. The external teeth 23a of the drive gear 23 are connected to the output shaft 12a of the motor 12 via a second reduction mechanism 52A, a second EA mechanism 54A, and a first reduction mechanism 51A. Drive gear 23 is an example of a first rotating member.

The clutch outer 24 is rotatably supported coaxially with the drive gear 23, and is directly or indirectly connected to the spool 4. In this embodiment, the clutch outer 24 is integrally connected to the inner peripheral portion of the spool 4 via a rotating body 27. The clutch outer 24 has a boss 24a connected to a shaft hole 27b of the rotor 27 so as to be rotatable together with the rotor 27, and a shaft hole 24b through which the tip end 7b passes. Clutch outer 24 is an example of a second rotating member.

FIG. 9 is a side view of the clutch 25. FIG. 10 is an exploded perspective view of the clutch 25. FIG. 11 is a diagram showing the off state of the clutch 25 (clutch pawl closed state) along arrow BB (see FIG. 9). FIG. 12 is a diagram showing the clutch on operation (clutch pawl open state) along the arrow BB (see FIG. 9). Next, the configuration of the clutch 25 will be described in more detail with reference to FIGS. 9 to 12.

The clutch 25 includes a drive gear 23, a clutch outer 24 rotatably supported coaxially with the drive gear 23, a pair of clutch pawls 41 provided on the drive gear 23, and a pair of clutch pawls 41 that bias the pair of clutch pawls 41. It has a clutch spring 42.

A pair of bosses 23e and 23h, a pair of attachment parts 23c and 23f, and a pair of stoppers 23d and 23g are formed to protrude from the end surface 23i of the drive gear 23. Ratchet internal teeth 24d are formed inside the outer peripheral wall 24c of the clutch outer 24.

The clutch pawl 41a is supported by the boss 23e so as to be able to swing about the boss 23e along the end surface 23i. The clutch pawl 41b is supported by the boss 23h so as to be able to swing about the boss 23h along the end surface 23i.

The clutch pawl 41a has a pressed portion 41ab formed on one side with respect to the boss 23e, and a claw portion 41aa formed on the other side with respect to the boss 23e. The clutch pawl 41b has a pressed portion 41bb formed on one side with respect to the boss 23h, and a claw portion 41ba formed on the other side with respect to the boss 23h.

The clutch spring 42a connects the attachment portion 23c and the pressed portion 41ab so as to bias the pressed portion 41ab in the direction toward the ratchet internal teeth 24d and to bias the claw portion 41aa in the direction away from the ratchet internal teeth 24d. A biasing member disposed between the two. The clutch spring 42a has one spring end attached to the attachment part 23c and the other spring end that pushes the pressed part 41ab in a direction toward the ratchet internal teeth 24d. The movement of the pressed portion 41ab in the direction approaching the ratchet internal teeth 24d is restricted by the stopper 23d so that the pressed portion 41ab does not come into contact with the ratchet internal teeth 24d.

Similarly, the clutch spring 42b connects the attachment portion 23f and the pressed portion so as to bias the pressed portion 41bb in the direction toward the ratchet internal teeth 24d and to bias the claw portion 41ba in the direction away from the ratchet internal teeth 24d. 41bb. The clutch spring 42b has one spring end attached to the attachment portion 23f and the other spring end that pushes the pressed portion 41bb in a direction toward the ratchet internal teeth 24d. The movement of the pressed portion 41bb in the direction approaching the ratchet internal teeth 24d is restricted by the stopper 23g so that the pressed portion 41bb does not come into contact with the ratchet internal teeth 24d.

Therefore, as shown in FIG. 11, when the rotation of the drive gear 23 is stopped, the clutch pawl 41a is held in a position where it does not engage with the ratchet inner teeth 24d of the clutch outer 24 according to the urging force of the clutch spring 42a. Ru. In other words, the claw portion 41aa does not engage with the ratchet internal teeth 24d.

Similarly, as shown in FIG. 11, when the rotation of the drive gear 23 is stopped, the clutch pawl 41b is held in a position where it does not engage with the ratchet inner teeth 24d of the clutch outer 24 according to the urging force of the clutch spring 42b. be done. In other words, the claw portion 41ba does not engage with the ratchet internal teeth 24d.

On the other hand, while the output shaft 12a of the motor 12 is rotating, the drive gear 23 is also rotating around the shaft hole 24b due to the rotation of the motor gear 20 and the connect gear 22 described above. When the drive gear 23 rotates, centrifugal force acts on the clutch pawls 41a and 41b.

When the drive gear 23 rotates in a direction corresponding to the winding direction of the seat belt 104 due to the rotation of the output shaft 12a, the clutch pawl 41a moves due to the centrifugal force while resisting the biasing force of the clutch spring 42a. The clutch pawl 41a moved by the centrifugal force engages with the ratchet inner teeth 24d of the clutch outer 24 (see FIG. 12). In other words, the claw portion 41aa engages with the ratchet internal teeth 24d. Conversely, when the drive gear 23 rotates in the direction corresponding to the pull-out direction of the seat belt 104 due to the rotation of the output shaft 12a, the clutch pawl 41a is moved toward the ratchet internal teeth 24d by the stopper 23d even if the centrifugal force is applied. Movement to is regulated. Therefore, engagement between the clutch pawl 41a and the ratchet internal teeth 24d is prevented (see FIG. 11). In other words, the claw portion 41aa does not engage with the ratchet internal teeth 24d.

Similarly, the clutch pawl 41b engages with the ratchet internal teeth 24d when the drive gear 23 rotates in a direction corresponding to the winding direction of the seat belt 104 due to the rotation of the output shaft 12a (see FIG. 12). That is, the claw portion 41ba engages with the ratchet internal teeth 24d. Conversely, the clutch pawl 41b does not engage with the ratchet internal teeth 24d when the drive gear 23 rotates in a direction corresponding to the pulling direction of the seat belt 104 due to the rotation of the output shaft 12a (see FIG. 11). In other words, the claw portion 41ba does not engage with the ratchet internal teeth 24d.

Therefore, when the drive gear 23 is rotating in the direction corresponding to the winding direction of the seat belt 104 due to the rotation of the output shaft 12a, the pawls 41aa and 41ba of the clutch pawls 41a and 41b are engaged with the ratchet internal teeth 24d. The current state will be maintained. In this engaged state, the rotational power of the output shaft 12a is transmitted to the motor gear 20, the connect gear 22, the second EA mechanism 54A, the connect gear 32, the idle gear 26, the drive gear 23, the pair of clutch pawls 41, and the clutch outer 24. It will be transmitted along the route. The clutch outer 24 is connected to the inner peripheral side of the spool 4 via a rotating body 27. Therefore, in such an engaged state, the rotational force of the output shaft 12a is transmitted to the spool 4, so that the seat belt 104 is wound around the spool 4.

On the other hand, when the drive gear 23 is rotating in the direction corresponding to the pulling direction of the seat belt 104 due to the rotation of the output shaft 12a, the pawls 41aa and 41ba of the clutch pawls 41a and 41b do not engage with the ratchet internal teeth 24d. The state is maintained. Furthermore, when the rotation of the output shaft 12a is stopped, the rotation of the drive gear 23 is stopped, so the state in which the pawls 41aa, 41ba of the clutch pawls 41a, 41b do not engage with the ratchet internal teeth 24d is maintained. be done. In these disengaged states, the rotational force of the rotating shaft of the spool 4 is transmitted to the rotating body 27 and the clutch outer 24 in this order, but is not transmitted to the drive gear 23. Therefore, in these disengaged states, the rotational force of the rotating shaft of the spool 4 is not transmitted to the output shaft 12a. In other words, the transmission of rotational force from the rotating shaft of the spool 4 to the output shaft 12a is interrupted.

In this way, the clutch 25 is a one-way clutch that interrupts the transmission of rotational force from the spool 4 to the motor 12 and transmits the rotational force from the motor 12 to the spool 4. Therefore, transmission of the rotational force from the spool 4 to the motor 12 is interrupted by the clutch 25, so that the occupant 111 can smoothly pull out the seat belt 104 from the retractor 1 or have the seat belt 104 wound around the retractor 1. Further, since the clutch 25 and the spool 4 are connected to each other via the rotating body 27, it is possible to prevent the rotational torque of the rotating body 27 of the pretensioner 8 from being transmitted to the motor 12 at the time of a collision.

FIG. 13 is a front view of the seat belt retractor in the second embodiment. FIG. 14 is a right side view of the seat belt retractor in the second embodiment. FIG. 15 is a left side view of the seat belt retractor in the second embodiment. FIG. 16 is a diagram showing a cut surface of the seat belt retractor in the second embodiment along arrow CC (see FIG. 15). FIG. 17 is an exploded perspective view of the seat belt retractor in the second embodiment.

The retractor 1B shown in FIGS. 13 to 17 is an example of a seatbelt retractor, and is a specific example of the retractor 1 shown in FIG. 2. The retractor 1B includes a first EA mechanism 53A, which is an example of the first EA mechanism 53, and a second EA mechanism 54B, which is an example of the second EA mechanism 54. The first EA mechanism 53A generates a base load BN by deforming the torsion bar 7 provided between the spool 4 and the lock mechanism 6. The second EA mechanism 54B limits the increase in the limit load LN by deforming the plate 43 provided between the motor 12 and the spool 4. The torsion bar 7 is an example of a first EA member, and the plate 43 is an example of a second EA member. The configuration of the retractor 1B will be described below with reference to FIGS. 13 to 17. Note that the description of the same configuration and effects as the retractor 1A will be omitted or simplified by referring to the above description.

The retractor 1B includes a frame 2, a spool 4, a vehicle sensor 5, a lock mechanism 6, a torsion bar 7, a pretensioner 8, and a power transmission mechanism 21B.

The power transmission mechanism 21B is an example of the power transmission mechanism 21 shown in FIG. 2. The power transmission mechanism 21B includes a motor 12, a retainer 29, a first reduction mechanism 51B, a second EA mechanism 54B, a second reduction mechanism 52B, and a clutch 25. The rotating body 27 may be one element of the power transmission mechanism 21B.

The motor 12 generates power to rotate the spool 4. Motor 12 is fixed to retainer 29 .

The retainer 29 includes a through hole 29e through which the output shaft 12a of the motor 12 passes, a shaft 29b that rotatably holds the second EA mechanism 54B, a boss 29a that rotatably holds the idle gear 26, and a rotating body 27. It has a holding hole 29c for rotatably holding.

The first speed reduction mechanism 51B is an example of the first speed reduction mechanism 51 (see FIG. 2), and includes a connect gear 32 and a plate holding gear 45. The first deceleration mechanism 51B shares the plate holding gear 45 with the second EA mechanism 54B.

The connect gear 32 is a motor gear attached to the output shaft 12a of the motor 12 so as to be able to rotate integrally with the output shaft 12a. The connect gear 32 has external teeth 32a and a shaft hole 32b into which the output shaft 12a is inserted.

The plate holding gear 45 has external teeth 45a that constantly mesh with the external teeth 32a of the connect gear 32, and a shaft hole 45b into which the shaft 29b is inserted. The external teeth 45a have a greater number of teeth than the external teeth 32a. Plate holding gear 45 rotates around shaft 29b.

The second EA mechanism 54B includes a plate 43 that is an EA member, and a pair of plate holding gears 44 and 45 that hold the plate 43 on both sides thereof. Next, the configuration of the second EA mechanism 54B will be explained with reference to FIGS. 18 to 21.

FIG. 18 is a perspective view of the first plate holding gear 44. FIG. 19 is a perspective view of the second plate holding gear 45. FIG. 20 is a diagram showing the state of the plate 43 before operation. FIG. 21 is a diagram showing a state in which the plate 43 is in operation.

The second EA mechanism 54B includes a plate holding gear 44 disposed on the inner peripheral side of the plate holding gear 45, and an annular plate 43 that can be plastically deformed. The plate 43 is, for example, a band-shaped or linear spring.

The plate holding gear 44 has a substantially disk shape and has external teeth 44a that constantly mesh with the external teeth 26a of the idle gear 26.

20 and 21 are plan views of the plate holding gear 45 viewed from the outside, and the outer shape of the plate 43 is shown in solid lines to improve visibility.

The plate 43 has an inner end 43a, an outer end 43b, and an intermediate section 43c between the inner end 43a and the outer end 43b. The inner end portion 43a is fixed to a groove 44c formed in an outer peripheral portion 44d of a convex portion 44e of the plate holding gear 44. The outer end portion 43b is fixed to a groove 45c formed in an inner peripheral portion 45d of a recess 45e of the plate holding gear 45. The intermediate portion 43c has an outer circumferentially extending portion P1, a bent portion P2, and an inner circumferentially extending portion P3. The outer peripheral extending portion P1 is a portion extending from the inner end portion 43a along the outer peripheral portion 44d in the belt drawing direction. The bent portion P2 is located between the outer circumferential extension portion P1 and the inner circumferential extension portion P3, and is a portion that is turned by 180° and folded back in the annular space S formed between the outer circumferential portion 44d and the inner circumferential portion 45d. It is. The inner peripheral extending portion P3 is a portion extending along the inner peripheral portion 45d in the belt winding direction.

When a load equal to or greater than the set value of the plate 43 is generated between the first plate holding gear 44 and the second plate holding gear 45, the second plate holding gear 45 is mounted on the first plate holding gear 44. The plate 43 starts to be pushed, and the plate 43 deforms along the inner circumferential portion 45d. The first plate holding gear 44 rotates in the opposite direction to the second plate holding gear 45. By deforming the plate 43, the excessive load generated by the motor 12 is limited and energy is absorbed. Although the plate 43 is mounted on the first plate holding gear 44 in the illustrated embodiment, it may be mounted on the second plate holding gear 45.

Although the seatbelt retractor and the seatbelt device have been described above using the embodiments, the present invention is not limited to the above embodiments. Various modifications and improvements, such as combinations and substitutions with part or all of other embodiments, are possible within the scope of the present invention.

For example, the number of clutch pawls is not limited to two, and may be one or three or more. Further, the number of gears included in each of the first speed reduction mechanism 51 and the second speed reduction mechanism 52 is not limited to two, and may be one or three or more.

1, 1A, 1B Retractor 2 Frame 4 Spool 5 Vehicle sensor 6 Lock mechanism 7 Torsion bar 8 Pretensioner 10 Control unit 12 Motor 14 Lock gear 17 Locking base 20 Motor gear 21 Power transmission mechanism 22 Connect gear 23 Drive gear 24 Clutch outer 25 Clutch 26 Idle gear 27 Rotating body 28 Retainer 29 Retainer 30 Torsion bar 32 Connect gear 41 Clutch pawl 43 Plate 44 Plate holding gear 45 Plate holding gear 51 First reduction mechanism 52 Second reduction mechanism 53 First EA mechanism 54 Second EA mechanism 55 first part 56 second part

Claims (16)

A spool for winding up the seat belt,
a locking mechanism that allows rotation of the spool when inactive and prevents rotation of the spool in a direction in which the seat belt is pulled out when activated;
The spool is provided between the spool and the locking mechanism, and when the spool is prevented from rotating by the locking mechanism, the spool is deformed by the rotational force of the seat belt due to the pull-out load, and the kinetic energy of the occupant is absorbed. a first energy absorption mechanism that absorbs
motor and
a deceleration mechanism that decelerates the power of the motor and transmits it to the spool ;
provided in the speed reduction mechanism, and after the spool is rotated in the winding direction of the seat belt by the motor in an emergency, when the lock mechanism is activated to prevent rotation of the spool; a second energy absorption mechanism that is deformed by the rotational force of the spool due to the pull-out load of the seat belt and absorbs the kinetic energy of the occupant ;
Seatbelt retractor with . The seat belt retractor of claim 1, wherein the motor and the spool are interconnected via the second energy absorbing mechanism. The seat belt retractor according to claim 2, wherein the speed reduction mechanism includes a first speed reduction mechanism and a second speed reduction mechanism that are interconnected via the second energy absorption mechanism. The seat belt retractor according to claim 3, wherein the second energy absorption mechanism and the spool are connected via the second reduction mechanism. The seat belt retractor according to any one of claims 1 to 4, further comprising a clutch that interrupts transmission of force from the spool to the motor and allows transmission of force from the motor to the spool. The clutch blocks transmission of force from the spool to the output shaft when the output shaft of the motor is stopped rotating, and transmits force from the output shaft to the spool when the output shaft is rotating. The seat belt retractor according to claim 5, which allows the transmission of force. The clutch is
a first rotating member that is connected to the output shaft via the second energy absorption mechanism and rotates according to rotation of the output shaft;
a second rotating member that is rotatably supported coaxially with the first rotating member and directly or indirectly connected to the spool;
a clutch pawl provided on the first rotating member,
The clutch pawl moves by centrifugal force caused by the rotation of the first rotating member and engages with the second rotating member, and when the first rotating member is stopped rotating, the clutch pawl engages with the second rotating member. 7. The seat belt retractor of claim 6, which does not engage a rotating member. The clutch pawl moves by the centrifugal force while resisting the biasing force of the biasing member and engages with the second rotating member, and when the first rotating member stops rotating, the clutch pawl engages with the second rotating member. The seat belt retractor according to claim 7, wherein the seat belt retractor is held in a position in which it does not engage with the second rotating member according to a force. The seat belt retractor according to claim 7 or 8, wherein the clutch pawl is swingably supported on an end surface of the first rotating member and engages with internal teeth of the second rotating member by the centrifugal force. . a pretensioner having a rotating body that rotates the spool in the winding direction of the seat belt when activated;
The seat belt retractor according to any one of claims 5 to 9, wherein the clutch and the spool are interconnected via the rotating body. The first energy absorbing mechanism has a first portion that engages with the spool and a second portion that is locked by the locking mechanism,
The seat belt retractor according to any one of claims 1 to 10, wherein the speed reduction mechanism transmits a load to the first portion side. The first energy absorbing mechanism generates a part of the load acting on the seat belt by deforming a torsion bar provided between the spool and the locking mechanism. Seat belt retractor as described in section. 13. The second energy absorption mechanism limits an increase in the load acting on the seat belt by deforming a torsion bar provided between the motor and the spool. Seat belt retractor as described. The second energy absorption mechanism limits an increase in the load acting on the seat belt by deforming a plate provided between the motor and the spool, according to any one of claims 1 to 12. seat belt retractor. The seat belt retractor according to any one of claims 1 to 14, further comprising a control unit that adjusts a load transmitted to the first energy absorption mechanism by controlling the motor. A seatbelt device comprising the seatbelt retractor according to any one of claims 1 to 15, the seatbelt, a tongue attached to the seatbelt, and a buckle with which the tongue is removably engaged. .

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