JP5399183B2 - Pretensioner - Google Patents

Description

  The present invention relates to a pretensioner that increases the tension of a webbing belt constituting a seat belt device of a vehicle in a vehicle sudden deceleration state or the like.

  In a pretensioner disclosed in Patent Document 1 (referred to as a power source in Patent Document 1), an energy absorption zone is provided in a cylinder. In this energy absorption zone, the inner diameter of the cylinder is reduced. When the piston slides in the cylinder by the gas generated by the gas generator and reaches the energy absorption zone, the energy absorption zone is expanded by the piston. The cylinder is deformed. Since the kinetic energy of the piston is used for the deformation of the cylinder generated in the energy absorption zone, the piston can reach the end of the cylinder without being destroyed.

Japanese Patent Laid-Open No. 5-193446

  In the configuration disclosed in Patent Document 1, the cylinder is deformed by the piston being expanded by the piston, and the cylinder is prevented from being destroyed as described above. However, the cylinder must be provided with mechanical strength that does not destroy the impact that the cylinder receives from the piston when the piston reaches the energy absorption zone, and the force that the piston pushes the cylinder.

  An object of the present invention is to obtain a pretensioner that can stop a piston without setting the mechanical strength of the cylinder particularly high in consideration of the above fact.

  The pretensioner according to the first aspect of the present invention has a gas generating means for generating gas by operating and both ends open, and the gas generated by the gas generating means is supplied from one end side to the inside. A cylinder that is slidable inside the cylinder, is slidably accommodated in the cylinder, and is slid toward the other end of the cylinder by the pressure of the gas supplied to the cylinder. A front end side is connected to a member, and a base end side enters the inside of the cylinder from one end side of the cylinder, penetrates through the piston, and is pulled toward the base end side, whereby the seat belt device is interposed via the predetermined member. And a connecting means for increasing the tension of the webbing belt constituting the cylinder, and a radial dimension along the radial direction of the cylinder is smaller than that of the piston. The piston is disposed on the other end side of the cylinder with respect to the piston, and the base end side of the connecting means penetrating the piston is integrally connected to the piston that slides to the other end side of the cylinder by the gas pressure. The gas that is pressed and moves to the other end side of the cylinder and pulls the connecting means, and the gas that is in contact with the surface of the piston on the other end side of the cylinder and passes between the piston and the connecting means is A pulling means for preventing the piston from coming out to the other end side of the cylinder, and provided at the other end side of the cylinder with respect to the pulling means to allow the pulling means to move toward the other end side of the cylinder. And a restricting means for restricting sliding of the piston toward the other end of the cylinder by interfering with the piston.

  In the pretensioner according to the first aspect of the present invention, when the gas generating means is activated and gas is generated in the gas generating means, the gas is supplied into the cylinder from one end side of the cylinder, and the pressure of the gas The piston in the cylinder slides to the other end side of the cylinder. When the piston slides to the other end side of the cylinder, the piston presses the tension means directly or indirectly, and the tension means moves together with the piston to the other end side of the cylinder.

  The pulling means is integrally connected to the base end side of the connecting means. Further, the connecting means penetrates the piston, and a buckle or a tongue is locked to the tip end side thereof. For this reason, when the pulling means moves to the other end side of the cylinder together with the piston, the connecting means is pulled by the pulling means. The front end side of the connecting means is connected to a predetermined member constituting the seat belt device, and when the connecting means is pulled, the seat belt is passed through the predetermined member constituting the seat belt device to which the connecting means is connected. The webbing belt constituting the apparatus is pulled, and the tension of the webbing belt increases. By pulling the webbing belt in this way, the occupant's body wearing the webbing belt is strongly restrained by the webbing belt.

  Here, in the pretensioner according to the present invention, the pulling means comes into contact with the surface of the piston on the other end side of the cylinder, so that the gas passing between the piston and the connecting means leaks to the other end side of the cylinder from the piston. To suppress that. Thereby, the pressure of the gas supplied into the cylinder can be efficiently contributed to the sliding of the piston, and consequently the buckle or the tongue.

  On the other hand, when the piston and the pulling means reach the position where the restricting means is provided in the cylinder by moving the piston and the pulling means to the other end side of the cylinder as described above, the piston is interfered by the restricting means and further. It becomes impossible to slide to the other end side of the cylinder. However, the restricting means allows the pulling means to move toward the other end of the cylinder. In this state, the sliding of the piston to the other end of the cylinder is restricted, and the piston does not slide to the other end of the cylinder any more, so the application of the pressing force from the piston to the tension means is canceled, By the pressure from the piston so far, the tension means is inertia and further moves to the other end side of the cylinder.

  In this way, the tension means further moves in a state where the sliding of the piston is restricted, so that the tension means is separated from the piston. As a result, gas can pass between the piston and the connecting means, and the increase in the internal pressure of the cylinder from the state where the sliding of the piston is restricted can be suppressed. For this reason, even if it is the structure which a piston engages with a part of cylinder after this state and this state, since the rise of the pressure of the gas which tries to move a piston to the other end side of a cylinder is suppressed, The cylinder can ensure sufficient mechanical strength against gas pressure.

  In the present invention, the predetermined member of the seat belt device connected to the connecting means is mechanically interposed between the connecting means and the webbing belt, and the connecting means is pulled to result in the webbing belt. The configuration is not limited to the specific configuration as long as the tension increases.

  Therefore, for example, the anchor member with the leading end of the webbing belt locked may be used as a predetermined member constituting the seat belt device, or a tongue provided on the webbing belt is mounted when the webbing belt is mounted. The buckle may be a predetermined member constituting the seat belt device.

  Further, the rotational force transmitting means means for rotating the spool (winding shaft) with which the longitudinal base end side of the webbing belt is locked in the direction of winding the webbing belt by rotating in a predetermined direction, and the connecting means are The seat belt device is configured to include a rotational force applying means for rotating the rotation transmitting member in the predetermined direction by being pulled toward the base end side, and the rotational force applying means is used as the predetermined member of the seat belt device. It is good.

  The pretensioner according to a second aspect of the present invention is the pretensioner according to the first aspect of the present invention, wherein the pretensioner is formed on the cylinder at the other end side of the intermediate portion of the cylinder, and the center of the cylinder in the inner peripheral portion. A restricting portion having a radial dimension from the axis that is greater than or equal to the outer diameter of the pulling means and less than the outer diameter of the piston is used as the restricting means.

  In the pretensioner according to the second aspect of the present invention, the restricting portion as the restricting means is formed as a part of the cylinder on the other end side of the intermediate portion of the cylinder. The restricting portion has a radial dimension from the center axis of the cylinder in the inner peripheral portion that is greater than or equal to the outer diameter of the tension means and less than the outer diameter of the piston. For this reason, although the pulling means can enter the restricting portion, the piston cannot enter the restricting portion. As a result, the pulling means is inertial in a state where the cylinder is interfered with the restricting portion, and the other end side of the cylinder. When moved, the pulling means is separated from the piston, and the gas can pass between the piston and the connecting means as described above.

  For example, the restricting portion that exerts such an action only needs to crush a part of the cylinder and partially shorten the radial dimension from the center of the cylinder, so that an increase in the number of parts and an increase in cost can be suppressed.

  As described above, in the pretensioner according to the present invention, the piston and the pulling means that slide with the gas pressure can be stopped without setting the mechanical strength of the cylinder to be particularly high.

It is sectional drawing which shows the outline of a structure of the pretensioner which concerns on one embodiment of this invention. It is sectional drawing by the side of the control means of the cylinder which shows the state in which sliding of the piston was controlled. It is sectional drawing corresponding to FIG. 2 which shows the state by which the movement of the tension | pulling means was controlled.

<Configuration of the present embodiment>
FIG. 1 is a sectional view showing a configuration of a pretensioner 10 according to an embodiment of the present invention.

  As shown in this figure, the pretensioner 10 includes a cylinder 11. The cylinder 11 is formed in a cylindrical shape (as an example, a cylindrical shape) whose both ends are opened as a whole by a cylinder body 12 and a restriction portion 13 as a restriction means formed continuously from one end of the cylinder body 12. Yes.

  The restriction portion 13 formed continuously from one end of the cylinder body 12 includes a piston interference portion 13A, a piece accommodating portion 13B, and a piece interference portion 13C. The piston interference portion 13A has a tapered shape in which the outer peripheral shape gradually decreases in the axial direction of the cylinder 11 toward the opposite side of the cylinder body 12, and the inner diameter of the inner peripheral portion is smaller than the inner diameter of the cylinder body 12. It is formed to become.

  A piece accommodating portion 13B is formed continuously from the end of the piston interference portion 13A opposite to the cylinder body 12. The piece accommodating portion 13B is formed in a cylindrical shape whose inner diameter dimension does not change in the axial direction, and the inner diameter dimension is smaller than the inner diameter dimension of the cylinder body 12. A piece interference portion 13C is continuously formed from the opposite side of the piece accommodating portion 13B to the piston interference portion 13A. The piece interference part 13C is formed in a tapered shape in which both the outer diameter dimension and the inner diameter dimension become smaller toward the opposite side to the piece accommodating part 13B.

  On the other hand, a piston 14 formed by forging a metal is accommodated inside the cylinder body 12 constituting the cylinder 11. The piston 14 includes a piston body 16. The piston body 16 gradually increases in outer diameter toward the tip (one end) side of the cylinder 11 (the side in the direction of arrow A in FIG. 1), and at least the outer peripheral shape of the end of the piston body 16 on the tip side of the cylinder 11. Is substantially equal to the inner peripheral shape of the cylinder body 12 by cutting the forged workpiece, and is larger than the inner diameter dimension of the end of the piston interference portion 13A opposite to the cylinder body 12 and the piece housing portion 13B. It has a frustum shape.

  A flange portion 18 whose outer peripheral shape is substantially equal to the inner peripheral shape of the cylinder main body 12 is provided at the end of the piston main body 16 on the base end (other end) side (the direction of the arrow B in FIG. 1) of the cylinder 11. It is formed substantially coaxially with respect to the end of the piston main body 16 on the front end side. The flange portion 18 and the end portion of the piston body 16 on the tip end side of the cylinder 11 are in sliding contact with the inner peripheral portion of the cylinder body 12, and the piston 14 can slide between the tip end of the cylinder body 12 and the other end. . A small diameter portion 20 having an outer diameter smaller than that of the flange portion 18 is formed substantially coaxially with the flange portion 18 at the end portion of the flange portion 18 on the proximal end side of the cylinder 11.

  An O-ring (O-ring) 22 formed in an annular shape from a rubber material or a synthetic resin material having elasticity similar to that of a rubber material is attached to the outer peripheral portion of the small diameter portion 20. The O-ring 22 is in close contact with the small-diameter portion 20 in the entire area along the outer peripheral direction of the small-diameter portion 20, and is in close contact with the inner peripheral portion of the cylinder 11. A space between the other end is sealed with an O-ring 22.

  On the other hand, a plurality of clutch balls 24 are arranged at appropriate intervals in the outer peripheral direction of the piston body 16 on the side of the flange portion 18 on the tip end side of the cylinder 11. When the piston 14 moves from the base end side of the cylinder 11 to the tip end side of the cylinder 11 (that is, when the piston 14 slides in the cylinder body 12 in the direction of arrow A in FIG. 1), each clutch ball 24 is inertial. When the outer peripheral surface (slope) of the piston main body 16 is moved, the clutch ball 24 is sandwiched between the outer peripheral portion of the piston main body 16 and the inner peripheral portion of the cylinder main body 12.

  In this state, when the piston 14 further moves toward the distal end side of the cylinder 11, the clutch ball 24 that moves along with the piston 14 toward the proximal end side of the cylinder 11 is deformed from the inner peripheral side of the cylinder body 12. Friction when the cylinder body 12 is deformed or cut by the clutch ball 24 restricts the sliding of the piston 14 toward the base end side of the cylinder 11.

  On the other hand, a through hole 26 is formed in the piston 14. One end of the through hole 26 is opened on the surface opposite to the flange portion 18 of the piston main body 16, and the other end is opened on the surface opposite to the flange portion 18 of the small diameter portion 20. The pretensioner 10 includes a wire 28 as a connecting means, and the wire 28 passes through the through hole 26. On the side of the piston 14 on the base end side of the cylinder 11, a piece 30 as a tension means is provided.

  A through hole 32 is formed in the piece 30, and the wire 28 passes through the through hole 32. The wire 28 that has passed through the through hole 32 to the side opposite to the piston 14 of the piece 30 is provided with a stopper, and the wire 28 can pass through the through hole 32 and escape to the piston 14 side of the piece 30. Can not. Therefore, the wire 28 is restricted from passing through the through hole 26 and coming out to the side opposite to the piece 30 of the piston 14.

  Further, the outer diameter dimension of the piece 30 is set to be equal to or smaller than the inner diameter dimension of the piece accommodating portion 13B and larger than the minimum inner diameter dimension of the piece interference portion 13C. Furthermore, the total length of the piece 30 along the axial direction of the cylinder 11 is set to be shorter than the length of the piece accommodating portion 13B along the axial direction of the cylinder 11.

  An end of the wire 28 opposite to the side on which the piece 30 is provided is locked to an anchor 34 as an anchor constituting a three-point seat belt device which is an aspect of the seat belt device of the vehicle, for example. . Although the detailed illustration is omitted, the anchor 34 is provided near the floor of the vehicle on one side in the width direction of the seat installed in the vehicle compartment. The anchor 34 is engaged with a leading end of a long belt-like webbing belt 36 constituting a three-point seat belt device. The base end side of the webbing belt 36 is folded downward while passing through a through anchor provided in the vicinity of the ceiling of the vehicle on one side in the seat width direction, and the vehicle floor on one side in the seat width direction. The proximal end side is locked to the spool of the webbing take-up device provided near the portion.

  The webbing belt 36 passes through the tongue plate between the above through anchor and the anchor 34. An occupant seated in the seat pulls the webbing belt 36 from the spool of the webbing take-up device and hangs the webbing belt 36 in front of the body. By attaching the tongue plate to the buckle 38, the webbing belt 36 is attached to the occupant's body.

  In the above description, the end of the wire 28 opposite to the side on which the piece 30 is provided is configured to be locked to the anchor 34, but what is the side on which the piece 30 of the wire 28 is provided? It is good also as a structure by which the edge part on the opposite side is latched by the buckle 38. FIG.

  As shown in FIG. 1, the pretensioner 10 includes a base cartridge 40 as a pretensioner body. The base cartridge 40 includes a main body 42. A cylinder mounting portion 44 is formed in the main body portion 42. A mounting hole 46 is formed in the cylinder mounting portion 44. One end of the mounting hole 46 opens at the outer surface of the cylinder mounting portion 44. The inner diameter dimension at the opening end of the cylinder mounting portion 44 is slightly larger than the outer diameter dimension at the distal end side of the cylinder 11, and the cylinder 11 can be inserted from the opening end of the mounting hole 46 from the distal end.

  Further, for example, a female screw (not shown) is formed on the inner peripheral portion of the mounting hole 46, and a male screw (not shown) is formed on the outer peripheral portion on the tip side of the cylinder 11 corresponding to this female screw. The cylinder 11 is connected to the base cartridge 40 by screwing the male screw of the cylinder 11 into the female screw of the mounting hole 46.

  On the other hand, the main body 42 is formed with a gas generator mounting portion 48 as a gas generating means mounting portion. The gas generator mounting portion 48 is formed on the side of the main body 42 along the direction intersecting the opening direction of the mounting hole 46 in the cylinder mounting portion 44. A gas generator mounting hole 50 is formed in the gas generator mounting portion 48. One end of the gas generator mounting hole 50 opens at the outer surface of the gas generator mounting portion 48.

  A gas generator 52 as a gas generating means is attached to the gas generator mounting portion 48. The gas generator 52 includes a fitting insertion portion 54. The outer peripheral shape of the insertion portion 54 is substantially equal to the inner peripheral shape of the gas generator mounting hole 50, and the gas generator 52 can be inserted from the opening end of the gas generator mounting hole 50. A flange portion 56 having an outer peripheral shape larger than the outer peripheral shape of the gas generator 52 is formed at one end (the upper end portion in FIG. 1) of the gas generator 52. When the fitting portion 54 is inserted into the gas generator mounting hole 50, the flange portion 56 interferes with the end portion of the gas generator mounting portion 48 on the opening end side of the gas generator mounting hole 50.

  A head portion 58 is formed on the opposite side of the flange portion 56 from the insertion portion 54. A cap 60 is mounted on the gas generator mounting portion 48 from the opposite side of the head portion 58 from the flange portion 56, and the cap 60 prevents the gas generator 52 from coming off from the gas generator mounting portion 48. The gas generator 52 mounted on the gas generator mounting section 48 generates gas instantaneously when activated, and jets the gas from the end of the fitting insertion section 54 opposite to the flange section 56.

  The base cartridge 40 is formed with a gas passage portion 62, and one end of the gas passage portion 62 is located at the end of the gas generator mounting hole 50 opposite to the side where the fitting insertion portion 54 of the gas generator 52 is inserted. Is open. The gas passage portion 62 is bent from an intermediate portion thereof toward the opening end side of the mounting hole 46, and the other end of the gas passage portion 62 is opened at the bottom portion 64 of the mounting hole 46. For this reason, when the gas ejected from the gas generator 52 is guided to the gas passage portion 62 and moves toward the insertion portion 54, the pressure of this gas causes the piston 14 to move to the proximal end side of the cylinder 11 (that is, the regulating portion 13 side). Press toward.

  On the other hand, the base cartridge 40 includes a guide portion 68. The guide portion 68 is formed on the opposite side of the main body portion 42 from the cylinder mounting portion 44. The guide portion 68 is formed with a wire passage portion 70 as a through hole as defined in the claims. One end of the wire passage portion 70 is opened at the inner peripheral portion of the gas passage portion 62. On the other hand, the other end of the wire passage part 70 is opened on the outer surface of the guide part 68 opposite to the main body part 42. Further, the inner peripheral shape of the wire passing portion 70 is set to be substantially the same shape as the outer peripheral shape of the wire 28 (strictly, a shape slightly larger than the outer peripheral shape of the wire 28), as shown in FIG. In addition, the wire 28 passes through the wire passage portion 70.

  As shown in FIG. 1, the penetration direction of the wire passage portion 70 is substantially the same as the penetration direction of the attachment hole 46 on the gas passage portion 62 side along the penetration direction of the attachment hole 46 formed in the cylinder attachment portion 44. Further, one end of the wire passage portion 70 (that is, the opening end of the wire passage portion 70 in the inner peripheral portion of the gas passage portion 62) is in the through direction of the attachment hole 46 formed in the cylinder attachment portion 44. Is coaxially opposed to the end of the mounting hole 46 on the gas passage portion 62 side. Therefore, the wire 28 can pass through the base cartridge 40 linearly.

  Further, on the other end side of the wire passage portion 70 (on the side opposite to the gas passage portion 62), a part of the inner peripheral surface of the wire passage portion 70 has one side in the opening radial direction of the wire passage portion 70 as the center of curvature. The wire 28 that is curved and pulled out from the other end of the wire passage portion 70 to the outside of the base cartridge 40 is curved along the inner peripheral surface of the wire passage portion 70 on the other end side of the wire passage portion 70. Yes. Thus, the wire 28 is bent toward the anchor 34 or the buckle 38 without being bent or bent excessively, and is locked to the anchor 34 or the buckle 38.

  Further, a wire protection cylinder 72 as a guard means is provided in the gas passage portion 62 corresponding to one end portion of the wire passage portion 70. The wire protection cylinder 72 is formed in a cylindrical shape whose inner peripheral shape is substantially equal to the inner peripheral shape of the wire passing portion 70. The wire protection cylinder 72 is formed so as to protrude from the inner wall of the gas passage 62 so as to be coaxial with one end of the wire passage 70, and the wire 28 that has passed through the wire protection cylinder 72 enters the wire passage 70. .

  On the other hand, a packing accommodating portion 74 is formed in the guide portion 68. The packing accommodating portion 74 is formed at an intermediate portion of the wire passage portion 70 (that is, between one end and the other end of the gas passage portion 62). Further, the packing housing portion 74 has a pair of sides facing each other in a front view of the base cartridge 40 parallel to a portion near the formation position of the packing housing portion 74 of the wire passage portion 70 and the other pair of sides facing each other being a wire. A rectangular shape orthogonal to a portion near the formation position of the packing accommodating portion 74 of the passage portion 70 is formed.

  A packing 80 is fitted inside the packing housing portion 74. The packing 80 is formed in a block shape whose outer peripheral shape is substantially equal to the inner peripheral shape of the packing accommodating portion 74 by rubber, an elastic member having elasticity similar to rubber, or a synthetic resin material having higher rigidity than such an elastic member. Yes. The packing 80 is in pressure contact with the inner wall of the packing housing portion 74 so that the packing 80 seals between the inner wall of the packing housing portion 74.

  Further, a through hole 82 is formed in the packing 80. In the state in which the inner diameter dimension of the through hole 82 is substantially equal to the outer diameter dimension of the wire 28 and the packing 80 is accommodated in the packing accommodating portion 74, one end communicates with the wire passing portion 70 on one end side of the packing accommodating portion 74. The end communicates with the wire passing portion 70 on the other end side than the packing housing portion 74. Therefore, the wire 28 that passes through the wire passage portion 70 passes through the through hole 82 of the packing 80 in the packing housing portion 74. In addition, as described above, the inner diameter dimension of the through hole 82 is substantially equal to the outer diameter dimension of the wire 28, so that when the wire 28 passes through the through hole 82, the inner peripheral portion of the through hole 82 and the outer peripheral portion of the wire 28. There is almost no gap between them.

  Further, a circular hole 90 is formed in the base cartridge 40. Fastening means such as fixing bolts pass through the circular hole 90. Fastening means such as fixing bolts that have passed through the circular hole 90 are fixed to the frame portion of the seat and the vehicle body, whereby the pretensioner 10 is attached to the vehicle.

<Operation and effect of the present embodiment>
Next, the operation and effect of the present embodiment will be described.

  When the occupant is seated on the seat and wears the webbing belt of the seat belt device, for example, when a detection means such as an acceleration sensor provided in the vehicle detects that the vehicle has suddenly decelerated, the ECU generates an ignition signal. Is output. When this ignition signal is input to the gas generator 52, the gas generating agent in the gas generator 52 is ignited. The ignited gas generating agent burns in a short time and generates gas rapidly.

  The gas generated in this way is sent to the gas passage portion 62. The gas fed into the gas passage portion 62 passes through the piston 14 located in the vicinity of the tip of the cylinder 11 (end portion on the gas passage portion 62 side of the cylinder 11) to the base end side (gas passage of the cylinder 11). Press to the opposite side of the part 62. In this way, the pressure of the gas applied to the piston 14 causes the piston 14 to press the seal member 110 toward the base end side of the cylinder 11, and further presses the piece 30 toward the base end side of the cylinder 11 via the seal member 110. While sliding to the base end side of the cylinder 11, that is, to the regulating portion 13 side.

  When the wire 28 is pulled by the piece 30 or the seal member 110 that slides in this way, the anchor 34 or the buckle 38 that is locked to the end of the wire 28 is pulled, thereby being attached to the body of the vehicle occupant. Tension is applied to the webbing belt 36 that is present. In this way, by applying tension to the webbing belt 36, slight slackness of the webbing belt 36, so-called "slack", is eliminated, and the restraining force that the webbing belt 36 restrains the occupant's body increases, making it stronger. The body of the passenger can be restrained.

  By the way, in the present embodiment, the wire 28 that passes through the gas passage portion 62 passes through the inside of the wire protection cylinder 72 that is formed so as to protrude from the inner periphery of the gas passage portion 62. A wire protection cylinder 72 is interposed between the generator mounting hole 50 and the wire 28. For this reason, when the gas passes through the gas passage portion 62, the gas is sprayed onto the wire protection cylinder 72 and is not sprayed directly onto the wire 28. Thus, in the present embodiment, the wire 28 can be protected from high-temperature and high-pressure gas.

  On the other hand, the piston 14 and the piece 30 that slide by the pressure of the gas supplied to the cylinder 11 as described above approach the restricting portion 13. Here, as described above, the inner diameter dimensions of the piston interference portion 13A and the piece accommodating portion 13B are equal to or larger than the outer diameter size of the piece 30. For this reason, as shown in FIG. 2, the piece 30 approaching the restricting portion 13 passes through the piston interference portion 13A from the opening end of the piston interference portion 13A on the cylinder body 12 side and enters the piece accommodating portion 13B.

  However, the inner diameter dimensions of the piston interference portion 13A and the piece accommodating portion 13B are smaller than the outer diameter size of the end portion of the piston main body 16 on the regulating portion 13 side. For this reason, as shown in FIG. 2, the piston 14 that has slid toward the regulating portion 13 side forms a piston interference portion 13 </ b> A, thereby forming a boundary portion between the cylinder body 12 and the piston interference portion 13 </ b> A inside the cylinder 11. Interference with the formed interference wall 13D and further sliding toward the regulating portion 13 are regulated.

  In this way, the piston 14 is interfered with the interference wall 13D and the sliding of the piston 14 is restricted, whereby the pressing of the piston 14 against the piece 30 is eliminated. However, the total length of the piece accommodating portion 13B is longer than the axial dimension of the piece 30, and the piece 30 is pressed against the piston 14 until then, so that the piece 30 is interfered with the piece interference portion 13C. The inside of the accommodating part 13B moves by inertia. As a result, the piece 30 is separated from the piston 14 as shown in FIG.

  Since the mutually opposing surfaces of the piston 14 and the piece 30 are in contact with each other, the space between the piston 14 and the piece 30 is sealed, and the space between the inner peripheral portion of the through hole 26 of the piston 14 and the outer peripheral portion of the wire 28 is sealed. The passage of gas to the piece 30 side of the piston 14 through passage is prevented or suppressed by the contact of the mutually opposing surfaces of the piston 14 and the piece 30. However, when the piece 30 is separated from the piston 14 as described above, the seal between the piston 14 and the piece 30 is released, and gas flows between the inner peripheral portion of the through hole 26 and the outer peripheral portion of the wire 28. It can pass through and escape to the piece 30 side of the piston 14.

  In this way, the gas that has escaped to the piece 30 side of the piston 14 further passes through the outer peripheral side of the piece 30 and is released to the outside of the cylinder 11 from the opening end of the piece interference part 13C opposite to the piece accommodating part 13B. Is done. Thus, although the piston 14 slid by the pressure of the gas collides with the interference wall 13D, immediately after that, the seal between the piston 14 and the piece 30 is released and the scavenging escapes, so that the collision with the interference wall 13D occurs. The impact applied to the interference wall 13D from the piston 14 at the time and immediately thereafter is effectively mitigated. Moreover, the piece 30 collides with the piece interference portion 13C and is stopped. However, after the piston 14 is interfered with the interference wall 13D, the piece 30 is merely moved by inertia, so the piece 30 is moved to the piece interference portion 13C. The impact when it collides with can be kept low.

  In this way, in the present pretensioner 10, since the impact applied to the cylinder 11 when the piston 14 and the piece 30 are stopped can be suppressed, the mechanical strength of the cylinder 11 can be suppressed to a low level. The cylinder 11 can be made smaller and lighter, for example, by reducing the thickness of the cylinder 11.

  In addition, the restricting portion 13 set in the cylinder 11 can be formed by relatively simple processing such as appropriately crushing one end of a general cylindrical cylinder. Is cheap.

  In each of the above embodiments, the pretensioner 10 for pulling the anchor 34 and the buckle 38 is used. However, the present invention is not limited to this, for example, a gas generator at the time of sudden deceleration of the vehicle. The spool of the webbing take-up device is forcibly rotated in the take-up direction by the pressure of the gas generated by the gas generating means such as 52, thereby causing the webbing belt 36 to be taken up by the spool. The present invention may be applied to a pretensioner that increases the tension.

10 Pretensioner 11 Cylinder 13 Restricting part (Regulating means)
14 piston 28 wire (connection means)
30 pieces (tensile means)
36 Webbing belt 52 Gas generator (gas generating means)

Claims (2)

Gas generating means for generating gas by operating; and
Both ends are opened, and the gas generated by the gas generating means is supplied to the inside from one end side;
A piston that is accommodated in the cylinder so as to be slidable inside the cylinder, and that slides to the other end side of the cylinder by the pressure of the gas supplied to the cylinder;
The front end side is connected to a predetermined member constituting the seat belt device, and the base end side enters the inside of the cylinder from one end side of the cylinder, penetrates through the piston, and is pulled to the base end side, thereby the predetermined end side. Connecting means for increasing the tension of the webbing belt constituting the seat belt device via a member;
A radial dimension along the radial direction of the cylinder is formed smaller than the piston, and is disposed on the other end side of the cylinder with respect to the piston, and a base end side of the connecting means penetrating the piston is integrally formed. It is connected and pressed by the piston that slides to the other end side of the cylinder by the pressure of the gas and moves to the other end side of the cylinder to pull the connecting means, and at the other end side of the cylinder in the piston A pulling means that suppresses the gas that tries to pass between the piston and the connecting means in contact with a surface from coming out to the other end side of the cylinder from the piston;
Provided on the other end side of the cylinder with respect to the pulling means, allows the movement of the pulling means toward the other end of the cylinder and interferes with the piston to slide the piston toward the other end of the cylinder. Regulatory means to regulate
Pretensioner with   It is formed in the cylinder on the other end side from the intermediate part of the cylinder, and the radial dimension from the central axis of the cylinder in the inner peripheral part is equal to or larger than the outer diameter dimension of the tension means and less than the outer diameter dimension of the piston. The pretensioner according to claim 1, wherein the regulated portion is the regulating means.

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