JP7543613B2 - Buckle pretensioner and seat belt device - Google Patents

Description

This disclosure relates to a buckle pretensioner and a seat belt device.

A buckle pretensioner has been proposed for a vehicle seatbelt device that operates in an emergency, such as a vehicle collision, to pull in a buckle connected to a wire via a wire, thereby increasing the restraining force of the webbing on the vehicle occupant.

Patent Document 1 discloses a buckle pretensioner that includes a buckle retraction direction changing means for moving the buckle and wire downward from a predetermined inclination direction to reduce the acute angle before an emergency, in order to prevent the occupant from slipping under the webbing and slipping forward when the buckle is retracted in an emergency, a phenomenon known as submarine braking.

JP 2019-172049 A

However, in the conventional technology described in Patent Document 1, the buckle's inclination angle gradually deepens throughout the entire buckle retraction operation when the pretensioner is activated. This type of operation leaves room for improvement in terms of preventing the submarine phenomenon.

The present disclosure aims to provide a buckle pretensioner and seat belt device that can effectively prevent the submarine phenomenon of occupants when activated.

A buckle pretensioner according to one aspect of an embodiment of the present invention is a buckle pretensioner that is activated in an emergency to retract a buckle to increase the restraining force of a vehicle occupant by a webbing, and includes an inclination adjustment unit that deepens the inclination angle of the buckle toward the front of the vehicle with respect to the vertical direction at an initial stage of retracting the buckle and then returns the inclination angle to its original state, a wire, a piston connected to one end of the wire, a cylinder that slidably houses the piston, and a gas generator that supplies gas to the piston for operating the piston in the direction of retracting the wire, the other end of the wire exiting the cylinder, going around an axis within the buckle toward the rear of the vehicle, and traveling in a parallel and reverse direction to be fixed to the cylinder, and the inclination adjustment unit has a regulating unit that regulates relative movement between the wire and the axis at an initial stage of the retracting operation and then releases the regulation .

The present disclosure provides a buckle pretensioner and seat belt device that can effectively prevent the submarine phenomenon of occupants when activated.

FIG. 1 is a configuration diagram of a seat belt device according to an embodiment of the present invention; FIG. 1 is a side view of a buckle pretensioner according to an embodiment; A perspective view of the buckle pulley and its surroundings AA cross-sectional view in FIG. FIG. 13 is a diagram showing a transition of the inclination angle of the buckle during a retracting operation in the embodiment. FIG. 6 is a diagram showing a change in the position of the webbing due to a change in the inclination angle of the buckle shown in FIG. FIG. 1 is a schematic diagram for explaining the effect of the present embodiment; FIG. 13 is a perspective view showing a first modified example of the restricting portion; BB cross-sectional view in FIG. FIG. 13 is a perspective view showing a second modified example of the restricting portion; 9. CC cross-sectional view in FIG.

The following describes the embodiments with reference to the attached drawings. To facilitate understanding of the description, the same components in each drawing are denoted by the same reference numerals as much as possible, and duplicate descriptions are omitted.

In the following description, the x, y, and z directions are perpendicular to each other. Typically, the x and y directions are horizontal, and the z direction is vertical. The x direction is the sliding direction of the piston, and the direction in which the buckle 7 is retracted is the x positive direction. The x direction is the fore-and-aft direction of the vehicle when the pretensioner 1 is installed in the vehicle, with the x positive side being the front of the vehicle and the x negative side being the rear of the vehicle. The y direction is the width direction of the vehicle when the pretensioner 1 is installed in the vehicle.

Fig. 1 is a diagram showing the configuration of a seat belt device 10 according to an embodiment. As shown in Fig. 1, the seat belt device 10 includes a webbing 11 (seat belt) for restraining an occupant that is unwound from a retractor 12. The retractor 12 is a device for winding up the webbing 11, and is fixed to the lower part of a center pillar 13 on the passenger compartment side. The webbing 11 unwound from the retractor 12 toward the upper part of the vehicle body is passed through a through ring 14 attached to the upper part of the center pillar 13, and folded back toward the lower part of the vehicle body. The tip of the webbing 11 is fixed to an anchor plate provided between the center pillar 13 and the seat 15.

A tongue 17 is provided between the through ring 14 and the anchor plate in the webbing 11 so that the webbing 11 can be inserted therethrough. The tongue 17 is attached to and detached from a buckle 7 arranged on the opposite side of the seat 15 from the anchor plate 16. When the tongue 17 is attached to the buckle 7, a portion 11A of the webbing 11 between the through ring 14 and the tongue 17 restrains the shoulders and chest of the occupant P. At this time, a portion 11B (waist belt) of the webbing 11 on the anchor plate side of the tongue 17 restrains the waist of the occupant P. More specifically, the waist belt 11B is arranged to pass through an area including the ilium I of the occupant P (see FIG. 6).

The buckle pretensioner 1 is a device that operates in an emergency, such as a vehicle collision, in a vehicle seatbelt device 10 to retract retractable members such as the webbing 11 and the buckle 7, thereby increasing the restraining force of the vehicle occupant by the webbing 11. The buckle pretensioner 1 is a type of pretensioner that is connected to the buckle 7 and retracts the buckle 7 of the seatbelt device 10.

The buckle pretensioner 1 includes a wire 2 connected to a buckle 7, a piston 3 (see FIG. 2) arranged on the wire 2, a cylinder 4 that slidably houses the piston 3, a gas generator 5 (see FIG. 2) that applies a driving force to the piston 3, and a bracket 6 connected to the cylinder 4 to position the wire 2.

The buckle pretensioner 1 also functions as the base of the buckle 7, and is fixed to the vehicle body by inserting a bolt through a fixing hole 61 formed in the bracket 6.

2 is a side view and partial cross-sectional view of the buckle pretensioner 1 according to the embodiment. When the buckle pretensioner 1 is installed in the vehicle, the extension direction of the cylinder 4 and the sliding direction of the piston 3 are in the x direction (front-rear direction of the vehicle). More specifically, the cylinder extends from the bracket 6 in the x positive direction (front side of the vehicle), and the piston 3 is arranged to move in the x positive direction when the pretensioner is activated. In addition, the part of the wire 2 exposed to the outside from the cylinder 4 and the buckle 7 at its tip are installed at an angle toward the front side of the vehicle (x positive direction) with respect to the vertical direction (z direction). Note that the part of the wire 2 exposed to the outside from the cylinder 4 may be covered with a part such as a cover member.

As shown in FIG. 2, one end of the wire 2 is inserted through the piston 3, which is slidably arranged in the cylinder 4, via the bracket 6, and connected to the wire end in the cylinder 4. Meanwhile, the other end of the wire 2 exits from the cylinder 4 via the bracket 6, is wound around the pulley 71 (axis) in the buckle 7, turns to the rear side of the vehicle (negative x direction side), and travels in parallel and in the opposite direction to be connected to the wire end 62 fixed in the bracket 6. The pulley 71 is installed so that the rotation axis extends along the vehicle width direction (y direction). In addition, the rotation axis of the pulley 71 is located at the bottom of the buckle 7 and approximately in the center in the width direction when viewed from the y direction. The part of the wire 2 between the piston 3 and the pulley 71 of the buckle 7 is also called the first wire 21, and the part between the pulley 71 of the buckle 7 and the wire end 62 is also called the second wire 22.

When viewed from the y direction, the first wire 21 and the second wire 22 are arranged substantially parallel to each other with a certain width between them, sandwiching the pulley 71 (the widthwise center of the buckle 7). The extension direction of the first wire 21 and the second wire 22 is inclined toward the front of the vehicle (positive x direction) with respect to the vertical direction (z direction).

In the example of FIG. 2, the end of the second wire 22 is fixed to the bracket 6 via the wire end 62, but the second wire 22 only needs to be fixed at least rearward of the vehicle relative to the first wire 21 and the pulley 71, and may be fixed directly to the cylinder 4, for example.

Figure 3 is a perspective view of the vicinity of pulley 71 of buckle 7. Figure 4 is a cross-sectional view taken along line A-A in Figure 3. For ease of explanation, in Figures 3 and 4, the directions are defined as the thickness direction (y direction), width direction (between the positive x direction and the negative z direction), and longitudinal direction (between the positive x direction and the positive z direction, perpendicular to the width direction) based on the shape of buckle 7.

The pulley 71 is supported rotatably around a rotation axis along the thickness direction (y direction) by a first housing 72 and a second housing 73 that are arranged facing each other at a predetermined distance in the thickness direction within the buckle 7. Between the first housing 72 and the second housing 73, a roller member 76 is attached to the entire circumferential surface of the pulley 71 in the circumferential direction, and the wire 2 is wound around the outer circumferential surface of this roller member 76.

The first housing 72, the second housing 73, and the pulley 71 are made of, for example, resin or metal. The roller member 76 is made of, for example, rubber or resin.

In particular, in this embodiment, a ring member 75 (regulating portion, inclination adjustment portion) is disposed between the first housing 72 and the wire 2. The ring member 75 is formed of, for example, resin, and fills the gap between the first housing 72 and the wire 2 while pressing the wire 2 against the second housing 73. As a result, the wire 2 is fixed to the first housing 72 and the second housing 73, and the relative movement of the wire 2 with respect to the pulley 71 and the buckle 7 is restricted. When the pretensioner 1 is activated and a retraction operation occurs in which the buckle 7 is retracted toward the cylinder 4 side via the wire 2, the ring member 75 receives the force transmitted from the wire 2 at the beginning of the retraction operation, thereby restricting the relative movement between the wire 2 and the pulley 71. When the retraction operation progresses and the retraction force transmitted from the wire 2 becomes large to a certain extent, the ring member 75 is plastically deformed to release the restriction, and as a result, the wire 2 becomes movable relative to the pulley 71.

In this embodiment, "restriction" refers not only to a configuration in which the wire 2 is fixed to the buckle 7, such as the ring member 75, to completely stop the relative movement of the wire 2 with respect to the buckle 7, but also to a configuration in which the wire 2 is made more difficult to move relative to the buckle 7, for example, by increasing frictional resistance or load.

5 is a diagram showing the transition of the inclination angle of the buckle 7 during the retraction operation of the buckle 7 in the embodiment. Due to the action of the ring member 75 (regulating part), the pulley 71 does not rotate and the wire 2 cannot move relative to the pulley 71 at the beginning of the retraction indicated by the symbol A in FIG. 5. Therefore, when a downward pulling force is transmitted through the first wire 21 connected to the piston 3, the first wire 21 is fixed to the buckle 7 through the ring member 75 on the vehicle front side from the position of the rotation axis of the pulley 71 (the width direction center of the buckle 7), so that a rotation moment M is applied to the buckle 7 in a direction tilting toward the vehicle front side (clockwise direction in FIG. 5) around the rotation axis of the pulley 71. In addition, while the first wire 21 is retracted into the bracket 6 and the part protruding to the outside becomes shorter, the second wire 22 does not receive a pulling force from the piston 3 side and does not change in length, so the buckle 7 is pulled downward biased by the first wire 21. As a result, as shown in FIG. 5, at the initial stage A of the pulling operation, the inclination angle of the buckle 7 toward the front of the vehicle (positive x direction) relative to the vertical direction (z direction) transitions to a deeper angle.

In the period (later period B) after the initial period A of the retraction operation, indicated by the symbol B in FIG. 5, the ring member 75 undergoes plastic deformation as described above, thereby enabling the pulley 71 to rotate. This eliminates the rotational moment M that was generated in the initial period A. Also, when the first wire 21 is pulled, the upper part of the second wire 22 passes through the pulley 71 and moves toward the first wire 21, and the second wire 22 also becomes as short as the first wire 21. As a result, as shown in FIG. 5, in the later period B of the retraction operation, the inclination angle of the buckle 7 returns to its original state before the retraction operation, and the buckle 7 is retracted toward the cylinder 4 along the extension direction of the first wire 21 and the second wire 22.

Figure 6 is a diagram showing the change in position of the webbing 11 (waist belt 11B) due to the change in the inclination angle of the buckle 7 shown in Figure 5. In Figure 6, the outline of an occupant P seated in a seat 15 is shown by a dotted line. As described above, when the buckle pretensioner 1 is in an inoperative state and the webbing 11 is normally fastened to the occupant P, the waist belt 11B of the webbing 11 is positioned above an area including the ilium I of the occupant P, restraining the waist of the occupant P.

Generally, when a vehicle receives a strong impact from the front due to a traffic accident or the like, the submarine phenomenon occurs, in which the body of the occupant P sinks into the seat surface of the seat 15 as if being pressed down. When the submarine phenomenon occurs, the iliac region I of the occupant P is likely to slip through the waist belt 11B, for example as shown by arrow C in Figure 6. Therefore, in the case of a conventional seat belt device, when the submarine phenomenon occurs, the occupant P leaves the seat 15 and sinks into the space in front of the seat 15, which may cause the occupant P to slip through the webbing 11 that is supposed to restrain and protect the occupant P, and may also cause the airbag to lose its effectiveness.

In contrast, in this embodiment, as described above, at the initial stage A of retraction of the buckle pretensioner 1, i.e., when the vehicle receives an impact, the buckle 7 instantly rotates toward the front of the vehicle and the inclination angle becomes deeper, so that the position of the waist belt 11B of the webbing 11 can be moved forward and downward from the normal state, for example, as shown by the arrow D in FIG. 6. As a result, even if the body of the occupant P tries to move toward the front of the vehicle when a vehicle impact occurs, the waist belt 11B of the webbing 11 can be prevented from coming off the position of the ilium I of the occupant P, and therefore the body of the occupant P can be prevented from slipping through the webbing 11 and moving forward.

In addition, in this embodiment, the inclination angle of the buckle 7 is not deepened throughout the entire retraction of the buckle 7, but the inclination angle of the buckle 7 is increased forward only in the initial stage A of the retraction (see FIG. 5). In general, the submarine phenomenon is likely to occur in a situation where the restraining force of the webbing 11 is relatively small and the body of the occupant P is relatively easy to move relative to the webbing 11. This state corresponds to the initial stage A of the retraction. On the other hand, in the later stage B of the retraction, the restraining force of the webbing 11 becomes sufficiently large and the submarine phenomenon is unlikely to occur. In other words, it is important to be able to take measures against the submarine phenomenon in the initial stage A of the retraction.

In this embodiment, the inclination angle of the buckle 7 is changed only at the initial stage A of the retraction operation, so that it is possible to increase the amount of movement of the waist belt 11B of the webbing 11 toward the front of the vehicle at the initial stage A of the retraction operation. As a result, the buckle pretensioner 1 of this embodiment can more reliably maintain the restraining position of the occupant P by the waist belt 11B of the webbing 11 at the initial stage A of the retraction operation, when the submarine phenomenon is likely to occur, and can effectively suppress the submarine phenomenon of the occupant P.

The effect of the initial stage A of the retraction operation described above will be further described with reference to FIG. 7. FIG. 7 is a schematic diagram for explaining the effect of this embodiment. FIG. 7(A) shows a schematic diagram of the tilt angle change structure of the buckle 7 by the buckle pretensioner 1 of this embodiment. Meanwhile, FIG. 7(B) shows a schematic diagram of the change structure in the buckle pretensioner 1A of the conventional method such as that of Patent Document 1 as a comparative example. In (A), the tilt angle of only the buckle 7 is increased. Meanwhile, in (B), the tilt angle of not only the buckle 7 but also the wire 2 is increased as a whole.

In Figure 7(A), the tilt angle of the buckle 7 is increased at the beginning A of the retraction operation. The increase in the tilt angle at this time is denoted as α. On the other hand, in Figure 7(B), the tilt angle of the buckle 7 and the wire is increased throughout the entire retraction operation. The increase in the tilt angle at this time is denoted as β. The increase in the tilt angle α and β can be considered to be roughly the same.

Focusing on the initial stage A of the retraction operation, the increase in (A) is α, whereas the increase in (B) is γ, which is a part of β. The increase in γ depends on the proportion of the initial stage A to the entire retraction operation, but is considered to be at least half or less of β. For this reason, it can be said that the increase in the inclination angle in the initial stage A of the retraction operation in (A) is certainly greater than the increase in γ in (B). In this way, in this embodiment, the increase in the inclination angle in the initial stage A of the retraction operation can be made greater than in the conventional method, and therefore the amount of movement of the webbing 11 toward the front of the vehicle in the initial stage A of the retraction operation can also be made greater accordingly.

In this embodiment, the ring member 75 functions as a restricting unit that restricts the relative movement of the wire 2 with respect to the pulley 71 of the buckle 7 and then releases the restriction. In addition, the ring member 75 as a restricting unit is included in an inclination adjustment unit that deepens the inclination angle of the buckle 7 toward the front of the vehicle with respect to the vertical direction at the beginning of the retraction operation of the buckle 7 and then returns the inclination angle to its original value.

In addition, in the conventional technology described in Patent Document 1 and the like, the angle of the looped wire is large, and in the latter half of the operation when the retraction progresses and more retraction force is required, the angle becomes even larger, so the component force in the retraction direction becomes smaller, resulting in poor efficiency as a pretensioner. In contrast, in this embodiment, only the inclination angle of the buckle 7 changes, and the inclination angle of the wire 2 does not change. Therefore, compared to the conventional technology described in Patent Document 1 and the like, in which the inclination angle of the buckle and the wire are changed integrally, there is less loss of the pulling force transmitted from the piston 3 to the wire 2, and the operating efficiency of the pretensioner can be maintained. In particular, this is particularly effective in the latter half of the operation (late retraction operation B) when the retraction progresses and more retraction force is required. Therefore, the buckle pretensioner 1 according to this embodiment can maintain the restraining position of the occupant P by the webbing 11 during a vehicle collision, while maintaining efficiency.

In addition, in the conventional technology described in Patent Document 1 and other documents, in order to orient the buckle forward, the fixed end of the looped wire must be positioned further forward of the vehicle than the initial position of the buckle, resulting in the problem that the area surrounded by the wire becomes dead space. In contrast, in this embodiment, the first wire 21 and the second wire 22 are positioned parallel to each other between the buckle 7 and the bracket 6, which makes it possible to avoid the increase in dead space as in the conventional technology described in Patent Document 1 and other documents, thereby enabling space saving.

In the above embodiment, a configuration in which a ring member 75 is disposed in the gap between the first housing 72 and the wire 2 is given as an example of a restricting section (tilt adjustment section) that restricts the movement of the wire 2 relative to the pulley 71 and then releases the restriction, but the configuration of such a restricting section is not limited to this.

Figure 8 is a perspective view showing a first modified example of the restricting portion. Figure 9 is a cross-sectional view taken along line B-B in Figure 8. As shown in Figures 8 and 9, instead of the ring member 75, a bent portion 77 may be provided that bends a portion of the second housing 73 in the thickness direction, and this bent portion 77 may be brought into contact with the outer periphery of the wire 2. As shown in Figure 9, the bent portion 77 presses the wire 2 toward the roller 76, thereby restricting the movement of the wire 2 relative to the pulley 71.

The bent portion 77 is made of, for example, metal, and by pressing the wire 2 against the metallic bent portion 77, the difference between the coefficients of static and dynamic friction is utilized to hold the wire down until it starts to move.

Figure 10 is a perspective view showing a second modified example of the restricting portion. Figure 11 is a cross-sectional view taken along the line C-C in Figure 10. As shown in Figures 10 and 11, instead of restricting the wire 2 with the bent portion 77 itself as in the first modified example, a protruding portion 78 protruding from the bent portion 77 towards the wire 2 may be provided in the gap between the bent portion 77 and the wire 2, and this protruding portion 78 may be brought into contact with the outer periphery of the wire 2. As shown in Figure 11, the protruding portion 78 presses the wire 2 towards the roller 76, thereby restricting the movement of the wire 2 relative to the pulley 71.

The protrusion 78 is formed, for example, from resin, and similar to the ring member 75, the restriction on the wire 2 is released by plastic deformation of the protrusion 78.

The present embodiment has been described above with reference to specific examples. However, the present disclosure is not limited to these specific examples. Design modifications to these specific examples made by a person skilled in the art are also included within the scope of the present disclosure as long as they have the features of the present disclosure. The elements of each of the above-mentioned specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of each of the above-mentioned specific examples can be combined in different ways as appropriate, as long as no technical contradictions arise.

In the above embodiment, a pulley 71 is provided on the buckle 7, and the wire 2 is wound around the pulley 71. However, as long as the wire 2 can be wound, a simple shaft may be used instead of the pulley 71.

In the above embodiment and modified example, the restricting portion is exemplified as a configuration that stops the relative movement of the wire 2 with respect to the pulley 71 (buckle 7) at the beginning of the retracting operation, such as the ring member 75, the bent portion 77, and the protruding portion 78. However, it is sufficient for the restricting portion to restrict at least the relative movement between the wire 2 and the pulley 71 at the beginning of the retracting operation. For example, the restricting portion may be configured to make it difficult for the wire 2 to move relative to the buckle 7 by increasing the frictional resistance between the pulley 71 and the wire 2 at the beginning of the retracting operation or by increasing the load for the wire 2 to move. An example of such a configuration is a configuration that restricts the rotation of the pulley 71 at the beginning of the retracting operation and then releases the restriction.

REFERENCE SIGNS LIST 1 buckle pretensioner 2 wire 3 piston 4 cylinder 7 buckle 10 seat belt device 11 webbing 71 pulley (shaft)
75 Ring member (regulating portion, tilt adjusting portion)
77 Bending portion (regulation portion, inclination adjustment portion)
78 Projection part (regulating part, inclination adjustment part)

Claims (5)

A buckle pretensioner that operates in an emergency to increase the restraining force of a vehicle occupant by a webbing by pulling in a buckle,
an inclination adjustment unit that deepens an inclination angle of the buckle toward the vehicle front side with respect to a vertical direction at an initial stage of a pulling-in operation of the buckle and then returns the inclination angle to its original value;
A wire ,
a piston connected to one end of the wire;
a cylinder that slidably accommodates the piston;
a gas generator that supplies gas to the piston for actuating the piston in a direction in which the wire is retracted;
Equipped with
The other end of the wire comes out of the cylinder, goes around the axis in the buckle toward the rear side of the vehicle, and travels in a parallel and reverse direction to be fixed to the cylinder,
The inclination adjustment unit has a regulating unit that regulates the relative movement between the wire and the shaft at an initial stage of the pulling operation and releases the regulation thereafter .
Buckle pretensioner. The shaft in the buckle is a pulley around which the wire is wound.
2. The buckle pretensioner according to claim 1 . The restricting unit restricts movement of the wire relative to the shaft and then releases the restriction.
3. The buckle pretensioner according to claim 1 or 2 . The regulating unit regulates the rotation of the pulley and then releases the regulation.
3. The buckle pretensioner according to claim 2 . A seat belt device comprising the buckle pretensioner according to any one of claims 1 to 4 .

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