WO2021153022A1

WO2021153022A1 - Pretensioner, retractor, and seat belt device

Info

Publication number: WO2021153022A1
Application number: PCT/JP2020/045893
Authority: WO
Inventors: 康二田中; 忠之浅子; 清史渡邉
Original assignee: ＪｏｙｓｏｎＳａｆｅｔｙＳｙｓｔｅｍｓＪａｐａｎ株式会社
Priority date: 2020-01-31
Filing date: 2020-12-09
Publication date: 2021-08-05
Also published as: JPWO2021153022A1; JP7265042B2

Abstract

Provided are a pretensioner, a retractor, and a seat belt device with which constraints on the design of the pretensioner can be relaxed while the release of working gas is minimized.　A motive power transmission device 32 comprises a resin-made, rod-shaped motive power transmission member 32a that transmits motive power to a ring gear 31, a tubular guiding member 32b that guides the motive power transmission member 32a to the ring gear 31, a gas generator 32c that supplies working gas to the interior of the guiding member 32b, a piston 32d positioned between the gas generator 32c and the motive power transmission member 32a, an elastic body 32e positioned in front of the piston 32d, a seal member 32f positioned on the rear side of the piston 32d, and a restraining part 32g that restrains the piston 32d formed in the guiding member 32b.

Description

Pretensioner, retractor and seatbelt device

The present invention relates to a pretensioner, a retractor and a seatbelt device, and more particularly to a pretensioner, a retractor and a seatbelt device suitable for a configuration in which a power transmission member is moved by a gas generator.

Vehicles such as automobiles are generally provided with a seatbelt device that restrains the occupant on a seat having a seating portion on which the occupant sits and a backrest portion located on the back of the occupant. Such a seatbelt device includes a webbing for restraining an occupant, a retractor for winding the webbing, a buckle arranged on the side surface of the seat, and a tongs arranged on the webbing, and the tongs are fitted to the buckle. The occupants are restrained in the seat by webbing. Further, it is becoming common for the retractor to have a pretensioner that removes slack in the webbing in an emergency such as a vehicle collision.

Such a patenter is powered by a power transmission member that rotates a spool that winds up a webbing, an elongated tubular pipe (guide member) that guides the power transmission member, and a working gas supplied into the pipe. It is often provided with a power transmission device including a gas generator that applies propulsive force to the transmission member (see, for example, Patent Document 1).

As described in Patent Document 1, when all the power transmission members are discharged from the pipe when the pretensioner is operated, the working gas may be released to the outside, and noise and smoke may be generated. Therefore, Patent Document 1 proposes various means for closing the final section of the pipe with a power transmission member (mass body or drive cylinder) so that the working gas is not discharged to the outside of the pipe.

By the way, in recent years, it has been researched and developed to use a resin-made elongated rod-shaped part as a power transmission member of a pretensioner. For example, Patent Document 2 has a configuration in which a piston provided with a deceleration element and a sealing element comes into contact with a stopper formed inside the pipe, and the stopper is plastically deformed by the deceleration element to stop the piston in the pipe. It is disclosed.

Japanese Patent No. 4654204 Special Table 2016-523198 Gazette

The inventions described in Patent Document 1 and Patent Document 2 are both configured to completely seal the pipe with a moving body (mass body, piston, etc.) that moves along the pipe. Since the pretensioner needs to wind up the webbing instantaneously (for example, within 1 second), the kinetic energy of the moving body tends to be inevitably large.

Therefore, in order to completely stop the moving body in the pipe, it is necessary to design a structure that can counter the kinetic energy of the moving body at the time of collision between the moving body and the stopper, which is a constraint on the design of the pretensioner. There is a problem of being severe.

The present invention has been devised in view of such problems, and provides a pretensioner, a retractor, and a seatbelt device capable of alleviating restrictions on the design of a pretensioner while suppressing the release of working gas. The purpose.

According to the present invention, in a pretensioner including a ring gear connected to a spool for winding a webbing that restrains an occupant and a power transmission device that transmits power to the ring gear in an emergency, the power transmission device. Is a power transmission member that transmits power to the ring gear, a tubular guide member that guides the power transmission member to the ring gear, a gas generator that supplies working gas inside the guide member, and the like. A piston arranged between the gas generator and the power transmission member, an elastic body arranged in front of the piston, a seal member arranged on the rear side of the piston, and the guide member formed on the guide member. The piston includes a restraint portion for restraining the piston, the piston is provided with a through hole formed in the front-rear direction, and the elastic body is configured to be able to seal the through hole and pass through the restraint portion. , A pretensioner characterized by that is provided.

The elastic body may have an outer diameter smaller than the inner diameter of the guide member and may be configured to be in contact with the inner surface of the guide member during compression.

The guide member may include an exhaust port formed on the tip side of the restraint portion.

The elastic body may have a substantially cylindrical shape, a substantially spherical shape, or an annular shape arranged on the outer circumference of the shaft member.

The elastic body may be provided with a recess or an annular groove formed at the rear end.

A plurality of the elastic bodies may be arranged in the axial direction of the guide member.

The pretensioner may be arranged between the elastic body and the power transmission member, and may include a resin protective member that protects the elastic body.

The protective member may be configured to be connectable to the elastic body.

The protective member may have a diameter smaller than the inner diameter of the guide member and larger than the inner diameter of the restraint portion.

The restraint portion may be a throttle portion formed on a part of the guide member.

The piston may be made of metal and have an outer diameter larger than the inner diameter of the restraint portion.

The power transmission member may be made of resin and have a rod shape.

The rear end of the power transmission member may have a spherical shape.

Further, according to the present invention, there is provided a retractor characterized by having a pretensioner having the above-described configuration.

Further, according to the present invention, there is provided a seatbelt device characterized by having a retractor provided with a pretensioner having the above-described configuration.

According to the pretensioner, retractor and seatbelt device according to the present invention described above, by forming a through hole in the piston and arranging an elastic body in front of the piston, the piston is elastic until it collides with the restraint portion. The through hole can be sealed by the body. Further, after the elastic body has passed through the restraint portion, the working gas can be discharged from the through hole, and the kinetic energy of the piston can be reduced. Therefore, the constraints on the design of the pretensioner can be relaxed while minimizing the emission of working gas.

It is a component development drawing which shows the retractor which concerns on one Embodiment of this invention. It is a conceptual diagram explaining the operation of an elastic body and a piston shown in FIG. 1, (A) is a state before the gas generator is activated, (B) is a state after the gas generator is activated, (C). Is a state in which the elastic body has reached the restraint portion, (D) is a state in which the piston has reached the restraint portion, and (E) is a state in which the elastic body has passed through the restraint portion. It is sectional drawing which shows the operation of the pretensioner shown in FIG. It shows the state after the operation. It is sectional drawing which shows the deformation example of the pretensioner shown in FIG. 1, (A) is the first deformation example of a piston, (B) is a second deformation example of a piston, (C) is the first deformation example of an elastic body. , (D) show a second modification of the elastic body. It is sectional drawing which shows the other modification of the pretensioner shown in FIG. 1, (A) shows the state before operation, (B) shows the state after an elastic body has passed a restraint part. It is sectional drawing which shows the other embodiment of the pretensioner shown in FIG. 1, (A) shows the second embodiment, (B) shows the third embodiment, (C) shows the fourth embodiment. .. It is sectional drawing which shows the other embodiment of the pretensioner shown in FIG. 1, (A) shows the 5th embodiment, (B) shows the 6th embodiment, (C) shows the 7th embodiment. .. It is an overall block diagram which shows the seat belt apparatus which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 8. Here, FIG. 1 is a component development view showing a retractor according to an embodiment of the present invention. 2A and 2B are conceptual diagrams for explaining the actions of the elastic body and the piston shown in FIG. 1. FIG. 2A is a state before the gas generator is activated, and FIG. 2B is a state after the gas generator is activated. , (C) shows a state in which the elastic body reaches the restraint portion, (D) shows a state in which the piston reaches the restraint portion, and (E) shows a state after the elastic body has passed through the restraint portion.

As shown in FIG. 1, the retractor 1 according to the embodiment of the present invention includes a spool 2 that winds up a webbing that restrains an occupant, a pretensioner 3 that winds up the webbing to remove slack in an emergency, and the like. The pretensioner 3 includes a ring gear 31 connected to the spool 2 and a power transmission device 32 for transmitting power to the ring gear 31 in an emergency. In FIG. 1, the webbing diagram is omitted.

The power transmission device 32 includes, for example, a resin rod-shaped power transmission member 32a that transmits power to the ring gear 31, a tubular guide member 32b that guides the power transmission member 32a to the ring gear 31, and a guide member 32b. A gas generator 32c that supplies working gas to the inside of the piston 32c, a piston 32d arranged between the gas generator 32c and the power transmission member 32a, an elastic body 32e arranged in front of the piston 32d, and a piston 32d. The seal member 32f arranged on the rear side, the restraint portion 32g formed on the guide member 32b and restraining the piston 32d, and the guide member 32h that supports the power transmission member 32a at the start of meshing between the power transmission member 32a and the ring gear 31. And have.

The spool 2 is a winding cylinder for winding the webbing, and is rotatably housed in the base frame 11 forming the skeleton of the retractor 1. The base frame 11 has, for example, a first end surface 111 and a second end surface 112 facing each other, and a side surface 113 connecting these end surfaces. The base frame 11 may include a tie plate 114 that faces the side surface 113 and is connected to the first end surface 111 and the second end surface 112.

Further, for example, the spring unit 4 is arranged on the first end surface 111 side, and the pretensioner 3 and the lock mechanism 5 are arranged on the second end surface 112 side. The arrangement of the spring unit 4, the pretensioner 3, the lock mechanism 5, and the like is not limited to the illustrated configuration.

Further, the first end surface 111 of the base frame 11 is formed with an opening 111a through which the shaft portion of the spool 2 is inserted, and the second end surface 112 of the base frame 11 is formed with a pawl of the lock mechanism 5 (not shown). ) Is formed with an opening 112a having internal teeth that can be engaged with. Further, a part of the pretensioner 3 (for example, the ring gear 31) is arranged inside the second end surface 112 of the base frame 11. Further, a lock mechanism 5 is arranged outside the second end surface 112 of the base frame 11, and the lock mechanism 5 is housed in the retainer cover 51.

The retainer cover 51 may be provided with a vehicle sensor 6 that detects sudden deceleration or tilt of the vehicle body. The vehicle sensor 6 has, for example, a spherical mass body (not shown) and a sensor lever 61 that is swung by the movement of the mass body. The vehicle sensor 6 may be fitted and fixed in the opening 112b formed in the second end surface 112 of the base frame 11.

The spool 2 has a cavity in the center, and a torsion bar 21 forming an axial center may be inserted through the spool 2. The torsion bar 21 is connected to the locking base 52 of the locking mechanism 5 whose first end is connected to the end of the spool 2, the second end is fixed to the spool 2, and the spring core of the spring unit 4 is fixed. It is connected to the. Therefore, the spool 2 is connected to the spring unit 4 via the locking base 52 and the torsion bar 21, and is urged in the direction of winding the webbing by the spring stored in the spring unit 4.

The means for applying the winding force to the spool 2 is not limited to the spring unit 4, and may be another means using an electric motor or the like.

The locking base 52 is provided with a powl (not shown) arranged so as to appear and disappear from its side surface. When the locking mechanism 5 is activated, the poul is projected from the side surface of the locking base 52 to engage with the internal teeth formed in the opening 112a of the base frame 11 and restrain the rotation of the locking base 52 in the webbing pull-out direction. do.

Therefore, even when a load is applied in the webbing pull-out direction while the lock mechanism 5 is activated, the spool 2 can be held in the non-rotating state until a load equal to or higher than the threshold value is applied to the torsion bar 21. can. When a load equal to or higher than the threshold value is generated on the torsion bar 21, the torsion bar 21 is twisted, so that the spool 2 relatively rotates and the webbing is pulled out.

Further, the lock mechanism 5 includes a lock gear 53 arranged so as to be adjacent to the locking base 52. The lock gear 53 includes a flywheel (not shown) that is swingably arranged, and when the webbing is faster than the normal pull-out speed, the flywheel swings and is formed on the retainer cover 51. Engage with the internal teeth. When the vehicle sensor 6 is activated, the sensor lever 61 engages with the external teeth formed on the side surface of the lock gear 53.

In this way, the rotation of the lock gear 53 is regulated by the operation of the flywheel or the vehicle sensor 6. Then, when the rotation of the lock gear 53 is restricted, a relative rotation occurs between the locking base 52 and the lock gear 53, and the powl protrudes from the side surface portion of the locking base 52 with the relative rotation.

The lock mechanism 5 is not limited to the illustrated configuration, and various conventionally existing configurations can be arbitrarily selected and used. Further, the spool 2 may include a shock absorbing mechanism formed by a combination of a shaft and a wire-shaped or plate-shaped plastic deformation member instead of the torsion bar 21.

The pretensioner 3 includes, for example, a ring gear 31 having engaging teeth on the outer circumference, a power transmission device 32, a pretensioner cover 33 for storing the ring gear 31, and a pin 34 for restricting the movement of the power transmission member 32a. , Is equipped. Further, although not shown, the pretensioner 3 may include a guide spacer that forms a moving space for the power transmission member 32a in the pretensioner cover 33.

The ring gear 31 is arranged so as to be located in the space formed between the pretensioner cover 33 and the base frame 11 (second end surface 112). The ring gear 31 may also be referred to as a drive wheel or a rotating member.

The pretensioner cover 33 is arranged inside, for example, the second end surface 112 of the base frame 11. Further, the pretensioner cover 33 is fixed to the base frame 11 (second end surface 112) together with the guide member 32b or directly by, for example, a plurality of fasteners 35a to 35c.

The power transmission device 32 is, for example, in the order of the gas generator 32c, the seal member 32f, the piston 32d, the elastic body 32e, and the power transmission member 32a from the rear end to the tip of the guide member 32b formed of the tubular pipe. Have been placed. The power transmission member 32a, the seal member 32f, the piston 32d, and the elastic body 32e are housed in the guide member 32b, and the guide member 32b is generated by the working gas generated from the gas generator 32c arranged at the rear end of the guide member 32b. Move inside.

The power transmission member 32a is formed in a linear rod shape before being inserted into the guide member 32b. For example, by press-fitting the power transmission member 32a into the guide member 32b from the tip side of the guide member 32b, FIG. 1 shows. As shown, it is housed inside the guide member 32b in a state of following the shape of the guide member 32b.

As shown in FIG. 1, the guide member 32b passes through the upper part of the first end surface 111, the upper part of the tie plate 114, and the upper part of the second end surface 112, and is a corner formed by the second end surface 112 and the side surface 113. It has a curved shape that extends downward from the upper part inside the part.

A guide member 32h is arranged at the tip of the guide member 32b. Further, at the tip of the guide member 32b, an opening 32i is formed to discharge the power transmission member 32a guided by the guide member 32h from the guide member 32b into the space formed by the pretensioner cover 33. Further, the guide member 32b includes a notch 32j that communicates from the tip of the guide member 32b to the opening 32i, and an insertion hole 32k through which the fastener 35a formed below the opening 32i is inserted.

The opening 32i is formed at a position adjacent to the guide member 32h of the guide member 32b, and constitutes an outlet portion of the power transmission member 32a. Further, the notch portion 32j has a function of positioning the guide member 32h in the circumferential direction, and a protrusion of the guide member 32h is inserted into the notch portion 32j.

The guide member 32h has, for example, a substantially cylindrical shape that can be inserted into the tip of the guide member 32b, and a sliding surface 32m that guides the power transmission member 32a to the opening 32i is obliquely formed at the end on the insertion side. Has been done. The sliding surface 32m may have a groove shape curved along the outer shape of the power transmission member 32a.

Further, a notch 32n through which the fastener 35a is inserted is formed in the lower part of the sliding surface 32m. Further, on the back side of the sliding surface 32m, a bolt hole 32o (see FIG. 3) for screwing a bolt (not shown) for fixing the guide member 32h and the guide member 32b to the base frame 11 (side surface 113) is formed. Has been done.

The restraint portion 32g is a portion through which the power transmission member 32a is passed and the piston 32d is stopped in the guide member 32b. The restraint portion 32g is, for example, a drawing portion formed in a part of the guide member 32b, and forms a protruding convex portion inside the guide member 32b. The restraint portion 32g is formed by, for example, pressing a part of the outer circumference of the guide member 32b.

As shown in FIGS. 1 and 2 (A), for example, the piston 32d has a head 32p having a substantially hemispherical shape and a substantially cylindrical body formed behind (planar side) the head 32p. It is a metal part composed of 32q. The head 32p has an outer diameter larger than the inner diameter Dr of the restraint portion 32g. The head 32p is provided with a through hole 32r formed in the front-rear direction. The through hole 32r is formed so as to communicate with the space formed by the body portion 32q.

A seal member 32f is arranged on the outer circumference of the body portion 32q. The seal member 32f is, for example, a substantially cylindrical elastomer component. The outer diameter of the seal member 32f is formed to be slightly larger than the inner diameter Dp of the guide member 32b, and is press-fitted into the guide member 32b. Therefore, the seal member 32f moves while maintaining a state of being in contact with the inner surface of the guide member 32b due to the pressure of the working gas supplied from the gas generator 32c.

The elastic body 32e is, for example, an elastomer part formed in a substantially cylindrical shape. The elastic body 32e has an outer diameter De smaller than the inner diameter Dp of the guide member 32b in a no-load state, and is configured to be in contact with the inner surface of the guide member 32b during compression. Further, the elastic body 32e has an elastic force that can be deformed into a shape that can pass through the restraint portion 32g at the time of compression.

The elastic body 32e may have recesses formed at the front end and the rear end. By forming a recess at the rear end of the elastic body 32e, the piston 32d can be brought into close contact with the head 32p. Further, by forming a similar recess at the front end, the elastic body 32e can be inserted into the guide member 32b without considering the front and back.

As shown in FIG. 2A, the elastic body 32e is inserted between the power transmission member 32a and the piston 32d in a no-load state in the state before the operation of the gas generator 32c. After that, when the gas generator 32c is activated and the working gas is supplied into the guide member 32b, the piston 32d moves forward while contacting the rear end of the elastic body 32e as shown in FIG. 2 (B). The front end of the elastic body 32e comes into contact with the rear end of the power transmission member 32a. Further, the seal member 32f is pressed against the head portion 32p of the piston 32d by the pressure of the working gas and is deformed to seal the gap between the guide member 32b and the piston 32d.

Further, the elastic body 32e is sandwiched between the power transmission member 32a and the piston 32d, compressed, and deformed so as to come into contact with the inner surface of the guide member 32b, and the power transmission member 32a moves forward together with the piston 32d. Let me. At this time, the through hole 32r of the piston 32d is sealed by the elastic body 32e.

After that, as shown in FIG. 2C, when the elastic body 32e reaches the restraint portion 32g, the elastic body 32e is further compressed and can pass through the restraint portion 32g as shown in FIG. 2D. The power transmission member 32a is moved forward while being deformed into a shape.

Then, as shown in FIG. 2E, when the piston 32d reaches the restraint portion 32g, the piston 32d collides with the restraint portion 32g and stops, and the elastic body 32e passes through the restraint portion 32g. At this time, since the elastic body 32e is released from the load by the piston 32d, it is restored to almost the original shape.

As shown in the figure, when the elastic body 32e is released from the piston 32d, the through hole 32r of the piston 32d shifts to a state where it is not sealed by the elastic body 32e, and the working gas passes through the through hole 32r and is more than the piston 32d. It flows into the space in front. Further, since the elastic body 32e is restored to have a gap between the elastic body 32e and the inner surface of the guide member 32b, the working gas can be discharged to the outside from the gap between the elastic body 32e and the guide member 32b.

The flow rate of the working gas discharged from the guide member 32b is controlled by the size of the through hole 32r and the size of the outer diameter of the elastic body 32e so that noise and smoke are not generated by the discharge of the working gas. It is restricted.

Therefore, according to the present embodiment, the through hole 32r can be sealed by the elastic body 32e until the piston 32d collides with the restraint portion 32g. Further, after the elastic body 32e has passed through the restraint portion 32g, the working gas can be discharged from the through hole 32r, and the kinetic energy of the piston 32d can be reduced. Therefore, the constraints on the design of the pretensioner 3 can be relaxed while minimizing the emission of the working gas.

Here, the operation of the pretensioner 3 will be described with reference to FIGS. 3 (A) to 3 (C). 3A and 3B are cross-sectional views showing the operation of the pretensioner shown in FIG. 1, in which FIG. 3A is a state before operation, FIG. 3B is a state in which an elastic body reaches a restraint portion, and FIG. It shows the state after passing through the restraint part.

As shown in FIG. 3A, the power transmission member 32a is housed in the guide member 32b in the state before the operation of the pretensioner 3. At this time, the tip of the power transmission member 32a is inserted to a position facing the guide member 32h.

In an emergency such as a vehicle collision, the pretensioner 3 operates, the working gas is supplied from the gas generator 32c into the guide member 32b, the power transmission member 32a is pushed out via the piston 32d and the elastic body 32e, and the guide member 32b Move along. At this time, the tip of the power transmission member 32a collides with the sliding surface 32m of the guide member 32h, is deflected toward the opening 32i, moves along the sliding surface 32m, and is formed on the outer circumference of the ring gear 31. It is released toward the engaged teeth.

In the pretensioner 3 using the resin rod (power transmission member 32a), the pressure applied to the power transmission member 32a generally tends to be the highest at the start of meshing with the ring gear 31. Therefore, by arranging the guide member 32h, which is a high-strength component, in this portion, the load generated at the start of meshing can be effectively received.

The power transmission member 32a released from the guide member 32b collides with the engaging teeth of the ring gear 31 and rotates the ring gear 31. After that, the power transmission member 32a moves along the passage formed by the pretensioner cover 33 while being plastically deformed by the engaging teeth of the ring gear 31.

As shown in FIG. 3B, when the elastic body 32e reaches the restraint portion 32g in a state where the movement of the power transmission member 32a is restricted by the pin 34, the power transmission member 32a is compressed and FIG. 3C ), The elastic body 32e passes through the restraint portion 32g, and the piston 32d collides with the restraint portion 32g and stops. The elastic body 32e that has passed through the restraint portion 32g is discharged in a state of being restored to a substantially original shape in the space formed by the power transmission member 32a and the guide member 32b.

Therefore, the kinetic energy of the piston 32d can be reduced because the working gas is discharged to the outside from the through hole 32r of the piston 32d without confining the working gas in the guide member 32b when the piston 32d is restrained. ..

Although not shown, the power transmission member 32a stops when the slack of the webbing is completely wound up. Therefore, when the amount of slack of the webbing is small, the power transmission member 32a is before the piston 32d reaches the restraint portion 32g. The movement of 32a may stop.

Next, a modified example of the pretensioner 3 will be described with reference to FIGS. 4 (A) to 5 (B). Here, FIG. 4 is a cross-sectional view showing a modified example of the pretensioner shown in FIG. 1, (A) is a first modified example of a piston, (B) is a second modified example of a piston, and (C) is a modified example of the piston. The first deformation example of the elastic body, (D) shows the second deformation example of the elastic body.

The first modification of the piston 32d shown in FIG. 4A is a recessed tip of the head 32p. The tip shape of the head 32p may be formed according to the shape of the elastic body 32e. For example, when the rear end of the elastic body 32e is flat, the tip of the head 32p may be formed flat, and when the rear end of the elastic body 32e is spherical, the tip of the head 32p may be spherical. It may be dented.

The second modification of the piston 32d shown in FIG. 4B shows a cavity 32s formed inside the head 32p. The cavity 32s may communicate with the through hole 32r as shown. Further, although not shown, the cavity 32s may be formed so as to surround the outer circumference of the through hole 32r. By forming the cavity 32s in this way, the weight of the piston 32d can be reduced and the kinetic energy can be reduced.

The first modification of the elastic body 32e shown in FIG. 4C is a spherical shape of the elastic body 32e. The elastic body 32e does not have to have a perfect spherical shape, and may have an elliptical shape or a cylindrical shape in which hemispheres are arranged at both ends. Further, although not shown, a cavity may be formed inside the elastic body 32e.

In the second modification of the elastic body 32e shown in FIG. 4 (D), the annular elastic body 32e is arranged on the outer circumference of the resin shaft member 32t. The shaft member 32t has an outer diameter smaller than the inner diameter Dr of the restraint portion 32g. As described above, the elastic body 32e can seal the through hole 32r of the piston 32d and the restraining portion 32g by forming a part of the elastic body 32e with the elastomer material even if the elastic body 32e is not entirely formed of the elastic material. May be configured to be passable.

Here, FIG. 5 is a cross-sectional view showing another modification of the pretensioner shown in FIG. 1, in which (A) is a state before operation and (B) is a state after an elastic body has passed through a restraint portion. , Is shown. The same components as those in the above-described embodiment are designated by the same reference numerals, and duplicate description will be omitted.

In the modified examples shown in FIGS. 5 (A) and 5 (B), an exhaust port 32u that discharges working gas is formed on the tip side of the restraining portion 32g of the guide member 32b. The exhaust port 32u may have, for example, a slit shape that is elongated from a position beyond the restraint portion 32g to the tip of the guide member 32b. Although not shown, the exhaust port 32u may be an opening formed in an elongated hole shape or a rectangular shape formed at a position exceeding the restraint portion 32g. Further, the exhaust port 32u may be a plurality of circular openings formed from a position exceeding the restraint portion 32g toward the tip end.

In such a modification, since it is not necessary to release the working gas from the gap between the elastic body 32e and the guide member 32b, the outer diameter De of the elastic body 32e is formed to have a size equal to or larger than the inner diameter Dp of the guide member 32b. You may. At this time, the elastic body 32e is press-fitted into the guide member 32b. The elastic body 32e has an elastic force sufficient to pass through the restraint portion 32g.

Next, other embodiments of the pretensioner 3 described above will be described with reference to FIGS. 6 (A) to 7 (C). Here, FIG. 6 is a cross-sectional view showing another embodiment of the pretensioner shown in FIG. 1, (A) is a second embodiment, (B) is a third embodiment, and (C) is a fourth embodiment. The embodiment is shown. 7A and 7B are cross-sectional views showing another embodiment of the pretensioner shown in FIG. 1, in which FIG. 7A is a fifth embodiment, FIG. 7B is a sixth embodiment, and FIG. 7C is a seventh embodiment. Is shown. The same components as those in the above-described embodiment are designated by the same reference numerals, and duplicate description will be omitted.

In the pretensioner 3 according to the second embodiment shown in FIG. 6A, the rear end 321 (end portion on the elastic body 32e side) of the power transmission member 32a is formed in a spherical shape. When the pretensioner 3 is operated, the elastic body 32e is pressed against the rear end 321 of the power transmission member 32a by the working gas. Therefore, when the power transmission member 32a has a corner at the rear end 321, stress concentration may occur in the elastic body 32e. By forming the rear end 321 of the power transmission member 32a into a smooth shape, such stress concentration can be reduced. In the present embodiment, the "spherical shape" does not have to be a spherical shape of a true sphere, and means a smooth shape without corners.

Further, when a gap is generated between the gas generator 32c and the piston 32d when assembling the pretensioner 3, a spacer 322 that fills the gap may be arranged. By arranging the spacer 322, it is possible to reduce the abnormal noise generated by the movement of the piston 32d in the normal state. The spacer 322 is composed of, for example, a metal coil spring.

The pretensioner 3 according to the third embodiment shown in FIG. 6 (B) is an improvement of the elastic body 32e shown in FIG. 4 (D) to be the elastic body 32e of the pretensioner 3 shown in FIG. 6 (A). It was used. The elastic body 32e shown in FIG. 6B includes a shaft member 32t, and the shaft member 32t has an annular diameter-expanded portion at a front end (end on the power transmission member 32a side) and a rear end (end on the piston 32d side). The enlarged diameter portion on the rear end side is formed to have a smaller diameter than the enlarged diameter portion on the front end side. With such a configuration, the elastic body 32e can be easily inserted. The enlarged diameter portion may be formed with a recess that can make surface contact with the rear end 321 of the power transmission member 32a.

In the pretensioner 3 according to the fourth embodiment shown in FIG. 6C, a plurality of elastic bodies 32e are arranged in the axial direction of the guide member 32b. Here, two elastic bodies 32e of the same material and the same shape are prepared and inserted into the guide member 32b side by side in the front-rear direction. With such a configuration, the preceding elastic body 32e can be used as a protective member for the trailing elastic body 32e. The plurality of elastic bodies 32e may be made of different materials or may have different shapes. Further, the number of elastic bodies 32e may be three or more.

The pretensioner 3 according to the fifth embodiment shown in FIG. 7 (A) is arranged between the elastic body 32e and the power transmission member 32a, and includes a resin protective member 323 that protects the elastic body 32e. Is. The protective member 323 is made of, for example, the same material as the power transmission member 32a. The protective member 323 has, for example, a substantially T-shaped cross section, and includes a recess 323a that can come into surface contact with the rear end 321 of the power transmission member 32a, and a protrusion 323b that can be locked to the elastic body 32e. When the rear end 321 of the power transmission member 32a has a planar shape, the recess 323a may be omitted.

Further, the elastic body 32e is provided with a fastening hole 324 into which the protrusion 323b can be inserted. The protective member 323 can be connected to the elastic body 32e by forming the entrance of the fastening hole 324 narrowly and forming the tip of the protrusion 323b thick. By integrating the elastic body 32e and the protective member 323 in this way, it is possible to facilitate handling when assembling the pretensioner 3. The protective member 323 is not necessarily a component that must be connected to the elastic body 32e, and the shapes of the protrusion 323b and the fastening hole 324 may be changed, or the protrusion 323b and the fastening hole 324 may be omitted, if necessary. You may.

Further, the diameter of the protective member 323 is formed to be slightly smaller than the inner diameter Dp of the guide member 32b. The diameter of the protective member 323 may be larger or smaller than the inner diameter Dr of the restraint portion 32g. By making the diameter of the protective member 323 larger than the inner diameter Dr of the restraint portion 32 g, the gap formed between the protective member 323 and the guide member 32b can be reduced, and the invasion of the elastic body 32e can be suppressed. Can be done. Since the protective member 323 is made of resin, it can pass through the restraint portion 32g due to the pressure of the working gas even if it has a diameter larger than the inner diameter Dr of the restraint portion 32g.

The pretensioner 3 according to the sixth embodiment shown in FIG. 7 (B) has a recess 325 formed at the rear end of the elastic body 32e shown in FIG. 7 (A). Further, the pretensioner 3 according to the seventh embodiment shown in FIG. 7 (C) has an annular groove portion 326 formed at the rear end of the elastic body 32e shown in FIG. 7 (A). By forming the recess 325 or the groove 326 at the rear end of the elastic body 32e in this way, the outer periphery of the rear end of the elastic body 32e can be expanded by the working gas of the pretensioner 3, and the sealing performance of the elastic body 32e can be expanded. Can be improved.

Next, the seatbelt device according to the embodiment of the present invention will be described with reference to FIG. Here, FIG. 8 is an overall configuration diagram showing a seatbelt device according to an embodiment of the present invention. In FIG. 8, for convenience of explanation, components other than the seatbelt device are shown by alternate long and short dash lines.

The seatbelt device 100 according to the present embodiment shown in FIG. 8 includes a webbing W for restraining an occupant, a retractor 1 for winding the webbing W, a guide anchor 101 provided on the vehicle body side for guiding the webbing W, and the like. The retractor 1 includes, for example, a belt anchor 102 for fixing the webbing W to the vehicle body side, a buckle 103 arranged on the side surface of the seat S, and a tongs 104 arranged on the webbing W. have.

The components other than the retractor 1 will be briefly described below. The seat S includes, for example, a seat portion S1 on which the occupant sits, a backrest portion S2 located on the back surface of the occupant, and a headrest portion S3 that supports the occupant's head. The retractor 1 is built in, for example, the B-pillar R of the vehicle body. Further, in general, the buckle 103 is often arranged on the side surface of the seat portion S1, and the belt anchor 102 is often arranged on the lower surface of the seat portion S1. Further, the guide anchor 101 is often arranged on the B pillar R. One end of the webbing W is connected to the belt anchor 102, and the other end is connected to the retractor 1 via the guide anchor 101.

Therefore, when the tongs 104 are fitted to the buckle 103, the webbing W is pulled out from the retractor 1 while sliding the insertion hole of the guide anchor 101. Further, when the occupant wears the seatbelt or releases the seatbelt when getting off, the webbing W is wound up by the action of the spring unit 4 of the retractor 1 until a certain load is applied.

The above-mentioned seatbelt device 100 is a normal seatbelt device in the front seat to which the retractor 1 according to the above-described embodiment is applied. Therefore, according to the seatbelt device 100 according to the present embodiment, the through hole can be sealed by the elastic body 32e until the piston 32d collides with the restraint portion 32g, and the elastic body 32e holds the restraint portion 32g. After passing through, the working gas can be discharged from the through hole 32r, and the kinetic energy of the piston can be reduced.

The seatbelt device 100 according to the present embodiment is not limited to the application to the front seats, and can be easily applied to the rear seats by omitting the guide anchor 101, for example. Further, the seatbelt device 100 according to the present embodiment can be used for vehicles other than vehicles.

Further, in the above-described embodiment, the case where the power transmission member 32a has a rod shape made of resin is described, but the power transmission member 32a may have a metal sphere (ball) shape or a rack and pinion. It may be an and pinion drive type rack.

It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

Claims

In a pretensioner that includes a ring gear connected to a spool that winds up a webbing that restrains an occupant and a power transmission device that transmits power to the ring gear in an emergency.
The power transmission device includes a power transmission member that transmits power to the ring gear, a tubular guide member that guides the power transmission member to the ring gear, and gas generation that supplies working gas to the inside of the guide member. A device, a piston arranged between the gas generator and the power transmission member, an elastic body arranged in front of the piston, a seal member arranged on the rear side of the piston, and the guide member. Including a restraining portion formed in the piston and restraining the piston.
The piston has a through hole formed in the front-rear direction.
The elastic body is configured to be able to seal the through hole and pass through the restraint portion.
A pretensioner that is characterized by that.
The pretensioner according to claim 1, wherein the elastic body has an outer diameter smaller than the inner diameter of the guide member and is configured to be in contact with the inner surface of the guide member during compression.
The pretensioner according to claim 1, wherein the guide member includes an exhaust port formed on the tip side of the restraint portion.
The pretensioner according to claim 1, wherein the elastic body is either a substantially cylindrical shape, a substantially spherical shape, or an annular shape arranged on the outer circumference of a shaft member.
The pretensioner according to claim 1, wherein the elastic body is provided with a recess or an annular groove formed at the rear end.
The pretensioner according to claim 1, wherein a plurality of the elastic bodies are arranged in the axial direction of the guide member.
The pretensioner according to claim 1, further comprising a resin protective member that is arranged between the elastic body and the power transmission member and protects the elastic body.
The pretensioner according to claim 7, wherein the protective member is configured to be connectable to the elastic body.
The pretensioner according to claim 7, wherein the protective member has a diameter smaller than the inner diameter of the guide member and larger than the inner diameter of the restraint portion.
The pretensioner according to claim 1, wherein the restraint portion is a throttle portion formed in a part of the guide member.
The pretensioner according to claim 1, wherein the piston is made of metal and has an outer diameter larger than the inner diameter of the restraint portion.
The pretensioner according to claim 1, wherein the power transmission member is made of resin and has a rod shape.
The pretensioner according to claim 12, wherein the power transmission member has a spherical shape at the rear end.
A retractor comprising the pretensioner according to any one of claims 1 to 13.
A seatbelt device comprising a retractor provided with the pretensioner according to any one of claims 1 to 13.