Seatbelt buckle device and seatbelt device

A seatbelt buckle device includes a buckle switch (40) having a switch substrate (42) and a slider part (50) which slides on the switch substrate (42) and a frame (20) which has a substantially U-shaped section and slidably holds an ejector (30) which operates synchronously with attachment/detachment of a tongue plate (1). The buckle switch (40) and the frame (20) are assembled integrally with each other as the a leg part (43) as a rear end of the switch substrate (42) is fixed to a side wall (22A) of the frame (20) through a switch substrate housing (45) and thus supported by the frame (20).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 35 U.S.C. § 371 national phase of PCT International Application No. PCT/JP2017/028311, filed Aug. 3, 2017, which claims the benefit of priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2016-154638, filed Aug. 5, 2016, the contents of which are incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to a seatbelt buckle device and a seatbelt device, and more particularly to a seatbelt buckle device including a buckle switch which detects whether the tongue of a seatbelt for an automobile or the like is in a locked state or an unlocked state, and to a seatbelt device.

BACKGROUND

In recent years, a seatbelt buckle device includes therein a buckle switch which detects whether an occupant is buckled up, so that airbag deployment output, a seatbelt winding motor, and the like are controlled depending on whether the seatbelt is buckled. An example of a known buckle switch of this kind is provided with a fixed contact and a movable contact in the buckle and configured to allow the movable contact to slide into contact with the fixed contact as a tongue plate is inserted, so that whether the seatbelt is buckled/unbuckled is detected on the basis of a change in the contact. Such a device is described by Japanese Patent Application Publication No. 2009-240528.

For example, the conventional buckle switch100shown inFIG. 7of the present disclosure includes a switch substrate101having a fixed contact102provided on one surface thereof (on the side of a frame112) and a slider part105which has a movable contact (not shown) and moves by sliding on the switch substrate101. The switch substrate101is positioned with its longitudinal ends being fitted in the grooves111of the lower case110and is arranged along one side wall113of the frame112. A connecting part106which protrudes from the slider part105to the side wall113is engaged with the forked groove116of an ejector115. The ejector115operates synchronously with detachment/attachment of the tongue plate (not shown) to be guided to the insertion hole114of the frame112and slide therein. The insertion of the tongue plate causes the ejector115to slide, so that the slider part105slides on the fixed contact102of the switch substrate101together with the movable contact, and the contact state is switched.

However, in the conventional buckle switch100shown inFIG. 7, the frame112having a plurality of buckle activating parts activated by the insertion of the tongue plate and the switch substrate101are fixed independently from each other in the lower case110, so that during assembling of the buckle switch100, the relative positions among the elements can vary, i.e., the frame112, the switch substrate101, and the lower case110should be adjusted to fall within tolerance ranges, which increases the man-hours for assembling. Since the frame112and the switch substrate101are provided independently from each other, the seatbelt buckle device may be relatively large. The switch substrate101is fitted and fixed in the grooves111of the lower case110, so that wear debris generated by the sliding movement of the buckle activating parts, and sand and dust in the buckle may stick to the switch substrate101, which may lower the contact resistance at the switch contact part (the contact point between the fixed contact102and the movable contact), and there has been a demand for a measure against the problem.

Since the fixed contact102is provided on the side of the frame112of the switch substrate101, wear debris generated as the buckle activating parts slide easily sticks directly to the fixed contact102, and the switch contact may catch foreign matter, which is more likely to cause a drop in the contact resistance.

SUMMARY

With the foregoing in view, it is an object of the present invention to provide a more compact seatbelt buckle device and to provide a seatbelt buckle device which allows a buckle switch to be assembled more easily and have improved reliability, and a seatbelt device including the seatbelt buckle device.

An object of the invention is achieved by the following features.

A seatbelt buckle device according to an embodiment of the present invention includes a buckle switch which having a switch substrate and a slider part which slides on the switch substrate, the buckle switch detecting whether a tongue is inserted in and connected with a buckle as the slider part moves by sliding on the switch substrate synchronously with attachment/detachment of the tongue and a frame which has a substantially U-shaped section and slidably holds an ejector, the ejector sliding synchronously with attachment/detachment of the tongue, the switch substrate being supported by the frame as one end thereof is fixed to a side wall of the frame.

The seatbelt buckle device of an embodiment of the present invention may also include a feature wherein the slider part includes a pin to be fitted to a hole part formed in the ejector, and the pin is offset to one end side of the switch substrate from a middle part of the slider part in a sliding direction.

The seatbelt buckle device of an embodiment of the present invention may also include a feature further including a case cover for storing the buckle switch and the frame, wherein the other end of the switch substrate is held by the case cover.

The seatbelt buckle device of an embodiment of the present invention may also include a feature wherein the buckle switch includes a substrate housing attached to one end of the switch substrate and held at the side wall of the frame, and one end of the switch substrate is fixed to the side wall of the frame through the substrate housing.

The seatbelt buckle device of an embodiment of the present invention may also include a feature wherein the buckle switch includes a substrate housing attached to one end of the switch substrate and held at the side wall of the frame, one end of the switch substrate is fixed to the side wall of the frame through the substrate housing, the other end of the switch substrate has a first flat surface in contact with the case cover, and one end of the switch substrate has a second flat surface in contact with the substrate housing and facing in the same direction as the first flat surface.

The seatbelt buckle device of an embodiment of the present invention may also include a feature wherein the substrate housing is provided with a raised part or a recessed part in the moving direction of the slider part, and the switch substrate is provided with a recessed part in abutment against the raised part of the substrate housing or a raised part in abutment against the recessed part of the substrate housing.

The seatbelt buckle device of an embodiment of the present invention may also include a feature further including a case cover for storing the buckle switch and the frame, wherein one end of the switch substrate is supported by the frame in a cantilever manner and the other end of the switch substrate is stored in a substrate storing part of the case cover in a non-contact state.

The seatbelt buckle device of an embodiment of the present invention may also include a feature wherein the buckle switch includes a substrate housing attached to one end of the switch substrate and held at the side wall of the frame, and one end of the switch substrate is fixed to the side wall of the frame through the substrate housing.

The seatbelt buckle device of an embodiment of the present invention may also include a feature wherein the switch substrate is provided with a fixed contact, the slider part is provided with a movable contact, and the movable contact is switched between a contact state and a non-contact state with respect to the fixed contact as the slider part moves by sliding on the switch substrate synchronously with attachment/detachment of the tongue.

The seatbelt buckle device of an embodiment of the present invention may also include a feature wherein the fixed contact is provided on a surface of the switch substrate on the opposite side to a surface of the switch substrate opposed to the side wall of the frame.

In the seatbelt buckle device according to the present invention, since one end of the switch substrate is fixed to a side wall of the frame and thus supported by the frame, and the switch substrate and the frame are assembled integrally with each other, the seatbelt buckle device may be reduced in size, and when the buckle switch and the frame are incorporated into the case cover, positional adjustment between the switch substrate and the frame is not necessary, so that the assembling may be easier. In particular, according to the present invention, the switch substrate can be held when the switch substrate cannot be held by a groove provided on a surface of a case cover having a frame provided thereon as with the conventional device because of the reduction in the size of the buckle device.

DETAILED DESCRIPTION

A seatbelt buckle device according to one embodiment of the present invention will be described in detail with reference to the accompanying drawings. Note that the following description will be provided in conjunction with various directions inFIG. 1, i.e., the front (Fr), the rear (Rr), the left (L), the right (R), the upward (U), and the downward (D). The arrow A from the front to the back refers to the direction in which the tongue plate1is inserted.

As shown inFIG. 1(a), a seatbelt buckle device10includes a frame20which is assembled with buckle activating parts such as a release button11which disconnects the tongue plate1and an ejector30activated synchronously with detachment/attachment of the tongue plate1and a buckle switch40provided along a side of the frame20to electrically detect whether the tongue plate1is connected to the buckle device10. The frame20and the buckle switch40are stored in a case cover60. An upper shell (not shown) mates with case cover60to fully enclose frame20.

The frame20is formed using a steel plate bent to have a substantially U-shaped section, and has a pair of side walls22A and22B provided to extend perpendicularly to a bottom plate25in the left-right direction. The side wall22A of the frame20is provided with a hole23and an engagement part24for attaching the buckle switch40. An insertion hole26is provided in the insertion direction of the tongue plate1along the bottom plate25at the upper parts of the side walls22A and22B of the frame20.

The left and right arm parts31of the plate-shaped ejector30are provided to protrude at the insertion hole26. The ejector30is provided in the frame20so that the ejector is pressed by the tongue plate1inserted in the seatbelt buckle device10to allow the left and right arm parts31and31A to move in the front-back direction in the insertion hole26.

The arm part31A of the ejector30which protrudes from the insertion hole26in the direction in which the buckle switch40is provided has an engagement hole32which is engaged with the pin54of the slider part50which will be described.

With reference toFIGS. 2 and 3(a) and (b), the buckle switch40includes a switch substrate42formed to have a substantially L shape, a resin substrate housing45which fixes one end of the switch substrate42to the frame20and from which lead wires71(seeFIG. 4(a)) connected to the terminals of fixed contacts42a,42b, and42c(which will be described later) are drawn, and the slider part50which slides on the switch substrate42synchronously with the tongue plate1.

The three fixed contacts42a,42b, and42care formed insulated from one another at one surface of the switch substrate42in the longitudinal direction. The switch substrate42has a leg part43provided to protrude downward at a rear end thereof and a rear raised part41provided to protrude rearward beyond the leg part43in the moving direction of the slider part50. The switch substrate42is fixed to the substrate housing45as the leg part43is inserted in a longitudinal groove46formed in the substrate housing45and the raised part41is inserted in a recessed part49formed in the substrate housing45and recessed in the moving direction of the slider part50. The switch substrate42is fixed to the substrate housing45so that the three fixed contacts42a,42b, and42cface the opposite side to the side wall22A of the frame20when the buckle switch40is attached to the frame20.

The switch substrate42is fixed to the side wall22A of the frame20through the substrate housing45as a protruding part47which protrudes from the substrate housing45is fitted to the hole23of the frame20and an engagement claw48provided to extend from the substrate housing45is engaged with the engagement part24of the frame20.

The switch substrate42fixed to the side wall22A of the frame does not have its front end44bound, and is supported in a cantilever manner as its rear end having the leg part43and the raised part41are fixed to the side wall22A of the frame20through the substrate housing45. More specifically, the switch substrate42elastically deforms in the plate thickness-wise direction (laterally), so that the front end44can be displaced in the direction toward or apart from the side wall22A.

More specifically, the front end44of the switch substrate42has a lower surface44aas a first flat surface, and the rear end of the switch substrate42has a lower surface41aof the raised part41as a second flat surface facing in the same direction as the lower surface44aof the front end44.

As shown inFIG. 4(b), the lower surface41aof the raised part41abuts against the bottom surface49aof the recessed part49of the substrate housing45, so that the switch substrate42may be restricted from moving in the up-down direction. The rear end surface41bof the raised part41abuts against the side wall49bof the recessed part49, so that the switch substrate42may be restricted from moving in the front-back direction (the moving direction of the slider part50).

As shown inFIG. 4(a), in the side wall part70which forms the recessed part49, a part70aon the frame side with respect to the switch substrate42is formed spread toward the frame20and the front side with respect to the part70bon the opposite side to the frame side so that the side wall part can guide the lead wires71. The outer surface of the part70aof the side wall part70on the frame side is curved in a raised shape in a top view in order to guide the lead wires71in the rearward direction.

The recessed part49has a lateral hole49cwhich forms a space as the switch substrate42is inserted, and the recessed part49is formed in an L-shape in a top view. In this manner, the presence of the lateral hole49cin the recessed part49allows the side wall part70to be reduced in weight and also the side wall part70on the side of the frame20to easily deform, so that the raised part41of the switch substrate42may be more easily inserted into the recessed part49.

Note that inFIG. 4(a), the reference numeral72refers to a holder which holds the lead wires71in a bundle.

Referring back toFIG. 1, the slider part50is a resin member formed to have a substantially U-shaped section and provided with a guide groove52at the inner surface of each of a pair of walls51which extends horizontally one upon the other. The guide grooves52are slidably fitted to the switch substrate42and guide the slider part50in the longitudinal direction of the switch substrate42.

The extended part53of the slider part50provided to extend from the upper wall51in the figure has the pin54formed to extend downward. In this manner, when the slider part50is assembled to the switch substrate42, the pin54is provided on the opposite side to the surface at which the fixed contacts42a,42b, and42cof the switch substrate42are provided. The pin54is offset to one end side of the switch substrate42from the middle part of the slider part50in the sliding direction. In this manner, the pin has a smaller length and a smaller size than the pin54without such offset.

The movable contact55having a plurality of contacts are fixed at the inner surface of the slider part50and slides together with the slider part50, which short-circuits between the fixed contacts42aand42bof the switch substrate42or between the42band42c, so that the contact state is switched.

The case cover60includes an upper case cover61as shown and a lower case cover (not shown) assembled with the upper case cover61. The upper case cover61includes a tubular part63having an opening62in the center into/from which the tongue plate1is inserted/withdrawn and a hood part64provided continuously with the tubular part63and having a substantially U-shaped section. A substrate storing part65which stores the front end44of the switch substrate42in a non-contact floating manner is provided on a front corner of the hood part64. The lower case cover is attached to cover the hood part64of the upper case cover61.

The buckle switch40is fixed to the side wall22A of the frame20as the pin54of the slider part50is inserted in the engagement hole32of the ejector30, the protruding part47of the substrate housing45and the hole23of the frame20are fitted with each other, and the engagement claw48of the substrate housing45is engaged with the engagement part24of the frame20. The buckle switch40assembled integrally with the frame20(i.e., as a sub-assembly) is incorporated into the case cover60together with the frame20. At the time, the front end44of the switch substrate42as a free end is stored without contacting the substrate storing part65of the upper case cover61.

More specifically, as shown inFIG. 5, the front end44of the switch substrate42has its lower surface44aopposed to the upper surface65aof the substrate storing part65with a slight gap therebetween, and its tip end surface44bopposed to the side surface65bof the substrate storing part65with a slight gap therebetween. In this manner, no excess load is applied on the front end44of the switch substrate42, and the switch substrate42may have sufficient durability.

Note that if the lower surface44aor the tip end surface44babuts against the upper surface65aor the side surface65bof the substrate storing part65and a large load acts thereupon, the front end44of the switch substrate42may restrict the switch substrate42from being displaced.

In the seatbelt buckle device10having the structure, when the tongue plate1is inserted in the seatbelt buckle device10, the ejector30is pressed by the tongue plate1to move in the insertion hole26of the frame20. In this manner, the slider part50having its pin54engaged with the engagement hole32of the ejector30operates synchronously with attachment/detachment of the tongue plate1and moves by sliding on the switch substrate42.

It is then determined whether the movable contact55has switched between the fixed contacts42aand42bor between the fixed contacts42band42cto a contact or non-contact state, so that the tongue plate1is inserted in and connected with the seatbelt buckle device10.

As in the foregoing, the seatbelt buckle device10according to the embodiment includes the switch substrate42provided with the fixed contacts42a,42b, and42c, the buckle switch40having the slider part50provided with the movable contact55to slide on the switch substrate42, and the frame20having a U-shaped section which operates synchronously with detachment/attachment of the tongue plate1and slidably holds the ejector30. The buckle switch40is supported by the frame20as the leg part43is fixed to the side wall22A of the frame20through the substrate housing45, and the buckle switch40and the frame20are integrally assembled with each other, so that the seatbelt buckle device10may be reduced in size. When the buckle switch40and the frame20are incorporated into the case cover60, positional adjustment between the switch substrate42and the frame20is not necessary, and therefore the assembling may be easier.

The leg part43of the switch substrate42is supported by the frame20in a cantilever manner, and the front end44of the switch substrate42is not bound and may elastically deform in the plate thickness-wise direction in response to the movement of the slider part50, so that foreign matter such as sticking dust may easily fall, a drop in the contact resistance at the switch contact part caused by foreign matter can be restricted, and the buckle switch40may have improved reliability.

The seatbelt buckle device10further includes the case cover60which stores the buckle switch40and the frame20, the front end44of the switch substrate42is stored in the substrate storing part65of the case cover60in a non-contact manner, and therefore the switch substrate42may be restricted from elastically deform excessively, so that the switch substrate42can be held in a stable manner.

The buckle switch40includes the substrate housing45attached to the leg part43of the switch substrate42and held by the side wall22A of the frame20, the leg part43of the switch substrate42is fixed to the side wall22A of the frame20through the substrate housing45, and therefore switch substrate42is supported in a cantilever manner.

The fixed contacts42a,42b, and42care provided on the surface of the switch substrate42on the opposite side to the surface opposed to the side wall22A of the frame20, so that wear debris generated because of the sliding movement of the buckle activating parts hardly sticks to the fixed contacts42a,42b, and42c, a drop in the contact resistance caused by foreign matter caught at the switch contact part can be prevented, and the buckle switch40may have improved reliability.

Furthermore, the slider part50includes the pin54fitted to the engagement hole32formed in the ejector30, and the pin54is offset to one end side of the switch substrate42from the middle part of the slider part50in the sliding direction, so that the pin54has a smaller length than the pin without such offset and the seatbelt buckle device10can be reduced in size.

Note that the invention is not limited by the described embodiment and may be modified and improved as appropriate.

The method for fixing one end of the switch substrate and the side wall of the frame, particularly the method for fixing the substrate housing and the side wall of the frame is not limited to the method according to the embodiment.

For example, according to the embodiment, the front end44of the switch substrate42is stored in the substrate storing part65of the case cover60in a non-contact manner, while the front end44of the switch substrate42may be held by an upper surface65aof a substrate holder provided on a front corner of the hood part64of the case cover60as in the modification shown inFIG. 6(a). In this case, the front end44of the switch substrate42is held by the substrate storing part65of the case cover60, and the rear end having the leg part43and the raised part41are held by the frame20, so that the switch substrate42may be held more stably at the ends. Note that the substrate holder65aof the case cover60may be a holding hole or a holding groove.

In this case, as shown inFIG. 6(b), at the front end44of the switch substrate42, the lower surface44aabuts against the upper surface65aof the substrate holder65, and the tip end surface44babuts against the side surface65bof the substrate holder65. Similarly to the embodiment, referring toFIG. 4(b), the lower surface41aof the raised part41of the switch substrate42abuts against the bottom surface49aof the recessed part49of the substrate housing45, and the rear end surface41bof the raised part41abuts against the side wall49bof the recessed part49. In this manner, according to the modification, the switch substrate42may be restricted from moving in the up-down and the front-back directions at the ends of the switch substrate42.

Since the side surface of the front end44in the plate thickness-wise direction abuts against the opposed surface65cof the substrate holder65, the movement of the switch substrate42in the plate thickness-wise direction may be restricted.

According to the embodiment, the raised part41is provided at the switch substrate42and the recessed part49is provided at the substrate housing45in order to restrict the movement of the switch substrate42in the front-back direction, while, alternatively, a recessed part recessed in the moving direction of the slider part50may be provided at the switch substrate42and a raised part to abut against the recessed part may be provided at the substrate housing45according to the present invention.

Also according to the embodiment, the fixed contacts are provided at the switch substrate and the movable contact is provided at the slider part, while the buckle switch according to the present invention is not limited by the embodiment. More specifically, in the buckle switch, one of the switch substrate and the slider part may be printed with a coil or provided with an embedded magnet in order to generate a magnetic field, and a change in the magnetic field may be detected and read using a detecting element such as a Hall effect element provided at the other of the switch substrate and the slider part, so that whether the tongue is inserted in and connected with the buckle may be detected.