Buckle and seat belt device

Abstract

Provided is a buckle that can suppress cost while increasing the product of mass and the distance from a rotary shaft of an inertial lever to the position of the center of gravity and reliably preventing detachment of the buckle and a tongue due to the force of inertia. A buckle 1 comprises a latch member 3 that locks onto a tongue 2 to latch the tongue 2, an operation button 12 for releasing the latching of the tongue 2 by the latch member 3, a base 13 that rotatably supports the latch member 3, and a lever 18 that is rotatably supported by the base 13 and abuts the operation button 12 to prevent movement of the operation button 12 in a release direction. The lever 18 has a rotary shaft 18a that is fitted into a groove that is formed in the base 13, a pin 18c that abuts the operation button 12, and a weight part 18b that is at the center of gravity of the lever 12. The weight part 18b includes a metal member 18m, and a portion of the weight part 18b that surrounds the metal member 18m, the rotary shaft 18a, and the pin 18c include a resin.

Description

Buckle and Seat Belt Device

[0001] The present invention relates to a seat belt device equipped on a seat of an automobile or the like and a buckle for this seat belt device.

[0002] Generally, in a vehicle such as an automobile, a seat belt device for restraining an occupant is provided on a seat having a seat bottom (seat cushion) on which the occupant sits and a backrest part (seat back) located behind the occupant. The seat belt device includes a webbing for restraining the occupant, a retractor for winding up the webbing, a buckle disposed on the side surface of the seat, and a tongue disposed on the webbing, and restrains the occupant to the seat by fitting the tongue into the buckle.

[0003] Generally, a buckle is configured to spring-urge a latch member having a claw portion for locking a tongue in a locking direction to the tongue. In such a buckle, the tongue supported by the seat belt is inserted into the buckle, the latch member of the buckle locks to the tongue, and the seat belt is worn on the occupant by holding this latch member in a locked state with a release prevention pin. Then, when a release button for releasing the engagement between the tongue and the buckle is pressed in the release direction to move the release prevention pin to an unlocked position, the tongue can be removed from the buckle.

[0004] Further, in the case of receiving a large impact such as in a vehicle collision, in order to surely maintain the engagement between the tongue and the buckle, a buckle provided with a shockproof device in which an inertia lever is rotatably provided on a base to prevent the release button from moving in the release direction is known.

[0005] The inertia lever of this shockproof device has a misaligned rotation axis and center of gravity position, and is a component that generates a moment of rotational inertia when inertia acts, and it is required to increase the product of the distance from the rotation axis to the center of gravity position and the mass. Since the conventional inertia lever had a structure of a single-piece metal (single metal), increasing the distance from the rotation axis to the center of gravity position led to an increase in the size of the inertia lever, an increase in cost, and it was difficult to efficiently generate a moment of rotational inertia.

[0006] International Publication No. 2005 / 082194

[0007] This invention has been made in view of the above-mentioned conventional circumstances, and aims to provide a buckle that can reduce costs while reliably preventing the tongue and buckle from separating due to inertial force by increasing the product of the distance from the rotation axis of the inertia lever to the center of gravity and the mass, and a seat belt device equipped with this buckle.

[0008] The buckle of the present invention comprises a latch member that engages with tongs to latch them, an operating button for releasing the latch of the tongs by the latch member, a base that rotatably supports the latch member, and a lever that rotatably supports the base and abuts against the operating button to prevent the operating button from moving in the release direction. The lever has a pivot shaft that fits into a groove formed in the base, a pin that abuts against the operating button, and a weight portion where the center of gravity of the lever is located. The weight portion includes a metal member, and the portion of the weight portion surrounding the metal member, the pivot shaft, and the pin include resin.

[0009] In one aspect of the present invention, a through hole extending in the direction of the buckle's short side is formed in the weight portion, and the metal member is inserted into the through hole.

[0010] In one aspect of the present invention, a protrusion is provided on the inner circumferential surface of the through hole.

[0011] In one aspect of the present invention, a recess is provided on the outer circumferential surface of the metal member, and the protrusion and the recess are fitted together.

[0012] The seat belt device of the present invention comprises a seat belt to be worn by an occupant, a tong movably supported by the seat belt, and a buckle of the present invention to which the tong is locked.

[0013] According to the present invention, the product of the distance from the rotation axis of the inertia lever to the center of gravity and the mass can be increased, thereby reliably preventing the tongue and buckle from separating due to inertial force, while keeping costs down.

[0014] This is an exploded view of the components of a buckle according to an embodiment of the present invention. Figures 2A and 2B are perspective views of the lever. This diagram illustrates the behavior of the operating button and lever in the inertial force in the release direction of the buckle.

[0015] Embodiments of the present invention will be described below with reference to the drawings.

[0016] Figure 1 is an exploded view of the components of a buckle 1 according to an embodiment of the present invention. Figures 2A and 2B are perspective views of the lever 18.

[0017] As shown in Figure 1, the buckle 1 is configured to be detachably attached to the tongue 2 of the seat belt device that restrains the occupant to the seat, and comprises the tongue 2 having an opening 21 and a latch member 3 having a claw portion 31 that can engage with the opening 21.

[0018] The buckle 1 also includes an upper cover 11 with an insertion opening for the tongs 2, an operating button 12 for releasing the engagement of the latch member 3, a base 13 that movably supports the latch member 3 and the operating button 12, a lower cover 14 connected to the upper cover 11 and housing the base 13, a lock pin 15 supported by the base 13 and restraining the movement of the latch member 3 engaged with the tongs 2 in the release direction, an ejector 16 slidably positioned in the longitudinal direction of the base 13 and capable of biasing the tongs 2 in the direction of detaching them from the buckle 1, an ejector spring 17 that biases the ejector 16, and a lever 18 (inertia lever) rotatably supported by the base 13 and preventing the movement of the operating button 12 when the operating button 12 receives an inertial force in the release direction when the tongs 2 and the latch member 3 are engaged.

[0019] The latch member 3 engages with the inserted tongs 2 to latch them. Specifically, the latch member 3 includes a claw portion 31 that rotates in a direction substantially perpendicular to the direction in which the tongs 2 enter and engages with the opening 21 of the tongs 2, a pair of flange portions 32 that are rotatably supported on the base 13, and a pair of stoppers 33 that protrude outward from both sides of the latch member 3.

[0020] A slider 34 is provided that is slidably positioned on the upper surface of the latch member 3, and a slider spring 35 is provided that biases the slider 34 from the flange portion 32 side toward the claw portion 31 side. The slider 34 has a pair of arms 34a that extend in the lateral direction of the buckle 1, and the arms 34a are configured to be able to be locked onto the operating button 12.

[0021] When the tongs 2 are inserted into the opening of the upper cover 11, the ejector 16 is pushed in by the tongs 2, causing the ejector 16 to contact the flange portion 32 and rotate the latch member 3 in a direction that engages with the tongs 2. As the latch member 3 rotates, the slider 34 also rotates, and the slider 34, which was restrained by the side portion of the lock pin 15, slides under the lock pin 15 due to the biasing force of the slider spring 35. Through this operation, the claw portion 31 of the latch member 3 engages with the opening 21 of the tongs 2, and the tongs 2 can be restrained by the buckle 1.

[0022] On the other hand, to release the tongs 2, pressing the operation button 12 pushes the slider 34 in, and the biasing force of the slider spring 35 pushes the slider 34 out from the side of the lock pin 15. Consequently, the latch member 3 rotates in the disengagement direction, and the opening 21 of the tongs 2 is released from the claw portion 31 of the latch member 3. The tongs 2 are then ejected to the outside of the buckle 1 via the ejector 16 by the biasing force of the ejector spring 17.

[0023] The base 13 is a U-shaped frame having a pair of side portions 13a that rotatably support the latch member 3, and a bottom portion 13b that connects the pair of side portions 13a. The bottom portion 13b has an opening (not shown) to avoid interference with the claw portion 31 of the latch member 3. The side portions 13a also have a slider passage that allows the movement of the slider 34, a lock pin support portion that supports the lock pin 15, and a guide hole that guides the movement of the operation button 12 in the longitudinal direction of the base. The side portions 13a also have a groove 13c into which the pivot shaft 18a of the lever 18 is fitted.

[0024] The operation button 12 has a pair of left and right side walls 12a that extend in the longitudinal direction of the buckle 1. Here, "left and right" refers to the left and right when viewed from the slider 34 side towards the operation button 12 side. Between the pair of side walls 12a, there are left and right protrusions 12c (see Figure 3) that extend in the longitudinal direction of the buckle 1. These protrusions 12c have engagement grooves 12d (see Figure 3) formed in them that are perpendicular to the direction of movement of the operation button 12.

[0025] As shown in Figure 2A, the lever 18 has a pivot shaft 18a, a weight portion 18b, and an engagement pin 18c. The weight portion 18b is a roughly rectangular prism shape extending in the direction of the buckle's short side, with a portion of it being an overhang portion 18d that protrudes toward the lower cover 14 side. The pivot shaft 18a is erected on both ends (in the direction of the buckle's short side) of this overhang portion 18. This pair of left and right pivot shafts 18a are rotatably fitted into grooves 13c in the side wall 13a of the base 13.

[0026] The engagement pin 18c is a round pin with a circular cross-section and extends in the short direction of the buckle. The engagement pin 18c is connected to the protruding portion 18d via the connecting portion 18e and is located on the operating button side of the pivot shaft 18a. Both ends of the engagement pin 18c engage with the engagement groove 12d of the operating button 12.

[0027] As shown in Figure 2B, a through hole 18h is formed in the center of the weight portion 18b in the direction of the lever's short side, and a metal member 18m is inserted into this through hole 18h. The metal member 18m is, for example, prismatic in shape.

[0028] The lever 18, in which the through hole 18h is formed, is made of resin. Polyacetal resin (POM), polyamide 6 (PA6) resin, glass fiber, etc., can be used as the resin. The material of the metal member 18m is not particularly limited, but iron, for example, can be used.

[0029] A protrusion (crush rib) may be provided on the inner circumferential surface of the through hole 18h to fix the metal member 18m inserted into the through hole 18h. Alternatively, a protrusion may be provided on the inner circumferential surface of the through hole 18h, and a recess may be provided on the outer circumferential surface of the metal member 18m, and the metal member 18m may be prevented from coming out by fitting the protrusion and the recess together. The method for preventing the metal member 18m from coming out is not particularly limited and may include surrounding it with the side portion 13a of the base 13, joining with adhesive, welding, crimping, etc.

[0030] It is preferable to set the thickness of the portion surrounding the through hole 18h in the weight portion 18b to about 0.8 to 2.0 mm and to increase the proportion of the metal member 18m.

[0031] The center of gravity of the lever 18 is located within the metal member 18m of the weight portion 18b.

[0032] In this way, by constructing the central part of the weight portion 18b of the lever 18 with a metal member 18m and the other parts with resin, the distance from the pivot axis 18a to the center of gravity of the lever 18 can be increased compared to conventional one-piece metal (single metal) inertia levers, and rotational inertia moment can be generated efficiently. In addition, since the parts other than the central part of the weight portion 18b are made of resin, manufacturing costs can be reduced.

[0033] For example, when the emergency retractor (ELR) pulls in the seat belt using a pretensioner (not shown) that activates in emergencies such as vehicle collisions, the tongue 2 is inserted into and engaged with the buckle 1, and as shown in Figure 3, the operating button 12 of the buckle 1 receives an inertial force in the release direction (to the right in the figure). At this time, the lever inertial force F is to the right. ＬＲ Then, the torque of the lever itself, which is turned clockwise to lever 18, is T ＬＲ This action causes the lever 18 to rotate clockwise.

[0034] Also, the inertia force F of the rightward-facing button ＢＲ When the operation button 12 is moved to the right, the engagement pin 18c immediately contacts the vertical surface of the engagement groove 12d. As a result, the engagement pin 18c exerts the button inertia force F of the release button 12. ＢＲ Because it is pressed, the lever 18 has a counterclockwise torque T ＢＲ It takes effect. ＢＲ <TＬＲ The torque is set in such a way that the lever 18 only attempts to rotate clockwise and does not rotate counterclockwise. As a result, movement of the operation button 12 in the release direction is prevented, and the latch between the buckle 1 and the tongue 2 is securely held.

[0035] In the above embodiment, the shape of the metal member 18m (shape of the through hole 18h) is not limited to a prismatic shape, but may be a cylindrical shape or other shape.

[0036] In the above embodiment, a configuration in which a through hole 18h is formed in the weight portion 18b has been described. However, instead of a through hole 18h, a configuration in which a recess is formed with one end on the left or right side closed and a metal member 18m is inserted into the recess may also be used.

[0037] In the above embodiment, the configuration of the buckle 1 other than the lever 18 is merely an example and is not limited to the illustrated configuration.

[0038] Although the present invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications are possible without departing from the intent and scope of the invention.

[0039] 1 Buckle 2 Tongs 3 Latch component 11 Upper cover 12 Operation button 13 Base 14 Lower cover 18 Lever

Claims

1. A buckle comprising: a latch member that engages with and latches tongs; an operating button for releasing the latch of the tongs by the latch member; a base that rotatably supports the latch member; and a lever that rotatably supports the base and abuts against the operating button to prevent the operating button from moving in the release direction, wherein the lever has a pivot shaft that fits into a groove formed in the base; a pin that abuts against the operating button; and a weight portion where the center of gravity of the lever is located, the weight portion including a metal member, and the portion of the weight portion surrounding the metal member, the pivot shaft and the pin including resin.

2. The buckle according to claim 1, wherein a through hole extending in the short direction of the buckle is formed in the weight portion, and the metal member is inserted into the through hole.

3. The buckle according to claim 2, wherein a protrusion is provided on the inner circumferential surface of the through hole.

4. The buckle according to claim 3, wherein a recess is provided on the outer circumferential surface of the metal member, and the protrusion and the recess are fitted together.

5. A seat belt device comprising: a seat belt to be worn by an occupant; tongs movably supported by the seat belt; and a buckle according to any one of claims 1 to 4 to which the tongs are locked.

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