JP2011098667A - State detection device and buckle device using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a state detection device for detecting a state by canceling, even if exposed to an external magnetic field, the influence thereof; and to provide a buckle device using the same. <P>SOLUTION: A buckle switch 2 serving as the state detection device includes: a housing 201 which is a casing; a slide portion 202 which is movably supported by the housing 201; a magnet 203 which is a permanent magnet moving in linking with the slide portion 202; a GMR sensor 210A serving as a first magnetic detector and positioned correspondingly to a first movement position of the magnet 203; a GMR sensor 210B serving as a second magnetic detector which is positioned correspondingly to a second movement position of the magnet 203 and is connected to the GMR sensor 210A in series; and a bias magnet 212 which gives a bias magnetic field to the first and second magnetic detectors. Output from a connection part between the GMR sensor 210A and the GMR sensor 210B is detected as a state of a position where the magnet 203 moves. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a state detection device and a buckle device using the same.

  The vehicle is provided with a seat belt device for restraining the seated occupant's body for safety. The webbing pulled out from the webbing take-up device of the seat belt device passes through a slit-like insertion hole formed in a through anchor provided above the center pillar of the vehicle, and is folded back to the vehicle lower side. It is fixed to an anchor provided in the vicinity of the winding device. Further, a tongue is provided on the webbing between the tip of the webbing fixed to the anchor and the folded part of the through anchor. The tongue plate of the tongue restrains the occupant's body by being inserted and held in the apparatus body of the buckle device.

  Here, the buckle device is provided with a state detection device for detecting that the tongue plate is inserted and held in the device main body. This state detection device detects a slide position state of the tongue plate in the buckle body, and is called a buckle switch. For example, the buckle body is provided with a printed circuit board on which first and second switch circuits having Hall ICs are mounted, and a slider to which a magnet facing the first and second switch circuits in contact or non-contact is attached. When the tongue plate is inserted into the buckle, the slider is pushed inward by the tongue plate and the slider moves inwardly. After the magnet is in contact with or close to the second switch circuit, the tongue plate is moved close to the first switch circuit. There is a buckle device including a state detection device configured to be latched by a buckle (see, for example, Patent Document 1).

  According to this buckle device, it is said that the operation from the state before the tongue plate is inserted into the buckle body to the state after the latching during the insertion and the operation after the latching can be reliably detected. .

JP 2001-260817 A

  However, the buckle device shown above may cause output abnormalities due to changes in magnetic field direction and magnetic flux density when the state detection device receives an external magnetic field, and as a result, the tongue plate insertion state is accurately detected. There was a problem that I could not.

  Accordingly, an object of the present invention is to provide a state detection device and a buckle device using the same, which can detect the state by canceling the influence even when an external magnetic field is received.

  [1] In order to achieve the above object, the present invention provides a housing, a slide portion that is movably supported by the housing, a permanent magnet that moves in conjunction with the slide portion, and a first of the permanent magnets. A first magnetic detector arranged corresponding to the first moving position and a second magnetic detector arranged corresponding to the second moving position of the permanent magnet and connected in series with the first magnetic detector. And a bias magnet for applying a bias magnetic field to the first and second magnetic detectors, and at the connecting portion of the first magnetic detector and the second magnetic detector. Provided is a state detection device that detects an output as a position state where the permanent magnet moves.

  [2] The state detection device according to [1], wherein the first and second magnetic detectors are GMR (Giant Magneto Resistance) sensors.

  [3] In order to achieve the above object, the present invention provides an apparatus main body capable of inserting and holding a tongue plate provided on a webbing of a vehicle seat belt apparatus, and the above [1] mounted in the apparatus main body. Or a state detection device according to [2].

  [4] Further, in order to achieve the above object, the present invention is an apparatus main body capable of inserting and holding a tongue plate provided on a webbing of a vehicle seat belt apparatus, and movably supported in the apparatus main body. A slide part, a permanent magnet that moves in conjunction with the slide part, a first magnetic detector that is arranged corresponding to a first movement position of the permanent magnet, and a second movement position of the permanent magnet And a second magnetic detector connected in series with the first magnetic detector, and a bias magnet for applying a bias magnetic field to the first and second magnetic detectors. The buckle device is characterized in that an output at the connecting portion of the first magnetic detector and the second magnetic detector is detected as a position state where the permanent magnet moves.

  [5] The buckle device according to [4], wherein the first and second magnetic detectors are GMR sensors.

  According to an aspect of the present invention, it is possible to provide a state detection device that can cancel the influence even when receiving an external magnetic field and perform state detection, and a buckle device using the state detection device.

FIG. 1 is an exploded perspective view of a buckle device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the buckle device showing a state before the tongue plate is inserted into the buckle body. FIG. 3A is a cross-sectional view of the state detection device showing the state before the tongue plate is inserted into the buckle body, and FIG. 3B is the state where the tongue plate is inserted into the buckle body and the magnet slides to the lock position. It is sectional drawing of the state detection apparatus which shows the state which carried out. FIG. 4A is a cross-sectional view of the state detection device showing a state before the tongue plate is inserted into the buckle body, and FIG. 4B is a circuit diagram showing the connection state of the GMR sensor, FIG. 5A is a diagram showing a resistance value when the positional relationship with the GMR sensor is FIG. 4A, and FIG. 5C is a characteristic diagram showing a relationship between the magnetic flux density B and the resistance value of the GMR sensor. It is the figure which plotted on the graph the resistance value R of each GMR sensor in case the positional relationship with a sensor is Fig.4 (a). FIG. 5A is a cross-sectional view of the state detection device showing a state after the tongue plate is inserted into the buckle body, and FIG. 5B is a circuit diagram showing a connection state of the GMR sensor, FIG. 6A is a diagram showing a resistance value when the positional relationship with the GMR sensor is FIG. 5A, and FIG. 6C is a characteristic diagram showing a relationship between the magnetic flux density B and the resistance value of the GMR sensor. It is the figure which plotted on the graph the resistance value of each GMR sensor in case the positional relationship with a sensor is Fig.5 (a). FIG. 6A is a cross-sectional view of the state detection device showing a state before the tongue plate is inserted into the buckle body, and is a view showing a case where an external magnetic field acts from the top to the bottom, FIG. 6B is a characteristic diagram showing the relationship between the magnetic flux density B and the resistance value of the GMR sensor, and the resistance value of each GMR sensor in the case of FIG. 6A in which an external magnetic field acts downward from the top. It is the figure which plotted R on the graph. FIG. 7A is a cross-sectional view of the state detection device showing a state before the tongue plate is inserted into the buckle body, and is a view showing a case where an external magnetic field acts from the bottom upward. FIG. 7B is a characteristic diagram showing the relationship between the magnetic flux density B and the resistance value of the GMR sensor, and the resistance value of each GMR sensor in the case of FIG. 7A in which an external magnetic field acts from the bottom to the top. Is a diagram plotted on a graph. 8 (a) and 8 (b) are other configuration examples in which each GMR sensor is provided with a bias magnet, and are equivalent to FIGS. 3 (a) and 3 (b), respectively.

(Embodiment of the present invention)
FIG. 1 is an exploded perspective view of a buckle device 1 according to an embodiment of the present invention. The buckle device 1 is a device main body capable of inserting and holding a tongue plate 130 provided on a webbing of a seat belt device of a vehicle, and a state detection device that is arranged in the device main body and detects a state of a slide position. A buckle switch 2. The buckle switch 2 which is this state detection device includes a housing 201 which is a housing, a slide part 202 which is movably supported by the housing 201, and a magnet 203 which is a permanent magnet which moves in conjunction with the slide part 202. The GMR sensor 210A as a first magnetic detector arranged corresponding to the first movement position of the magnet 203 and the GMR sensor 210A arranged in series with the second movement position of the magnet 203 A GMR sensor 210B as a connected second magnetic detector, and a bias magnet 212 for applying a bias magnetic field to the first and second magnetic detectors, and a connecting portion between the GMR sensor 210A and the GMR sensor 210B Is detected as a moving position of the magnet 203.

  FIG. 2 is a cross-sectional view of the buckle device 1 showing a state before the tongue plate is inserted into the buckle body. The buckle device 1 includes a case 14 that constitutes the device body. The case 14 is a box-shaped cylindrical member that is open at both ends in the longitudinal direction, the opening at one end in the longitudinal direction is an anchor insertion port 16, and the opening at the other end in the longitudinal direction is a tongue insertion port 18. Yes. A base 20 that constitutes the main body of the apparatus together with the case is housed inside the case 14.

  As shown in FIGS. 1 and 2, the base 20 includes a flat bottom plate 22 that is elongated along the longitudinal direction of the case 14. A substantially plate-like anchor plate 24 as an anchor member is superposed on one end side in the longitudinal direction of the bottom plate 22, and the bottom plate 22 and the anchor plate 24 are mechanically connected by a rivet (not shown). The other end of the anchor plate 24 is fixed to the vehicle body (not shown) at the side of the vehicle seat, and the buckle device 1 is attached to the vehicle.

  On the other hand, side walls 32 are erected from both ends in the width direction of the bottom plate 22 in the thickness direction of the bottom plate 22, and ejectors 34 as moving bodies are disposed between the side walls 32. A part of the ejector 34 is engaged with a guide hole 36 formed in the bottom plate 22, and can slide within a predetermined range along the guide hole 36 in the longitudinal direction of the bottom plate 22. The ejector 34 is urged from the housing 201 side to the other end in the longitudinal direction of the bottom plate 22 via an ejector spring 206.

  Further, the buckle switch 2 is attached to the bottom plate 22, and as shown in FIG. 2, the end face of the slide portion 202 located on the opening side of the housing 201 is attached in a state of being in contact with the pressing projection 34a of the ejector 34. It has been. Therefore, the ejector 34 is urged toward the other end in the longitudinal direction of the bottom plate 22 by the stroke spring 204 and the ejector spring 206.

  FIG. 3A is a cross-sectional view of the buckle switch 2 showing a state before the tongue plate 130 is inserted into the buckle body. The buckle device 1 includes a buckle switch 2 as a state detection device. The buckle switch 2 includes a housing 201 as a housing, a slide portion 202 supported by the housing 201 so as to be linearly movable, a magnet 203 that is a permanent magnet that moves linearly in conjunction with the slide portion 202, a magnet Stroke spring 204 as an elastic member interposed between 203 and housing 201, and GMR (Giant Magneto Resistance) sensor 210A as a magnetic detector for detecting a change in magnetic flux density from magnet 203, 210B is comprised.

  The housing 201 is made of, for example, a nonmagnetic material such as resin. It has a cylindrical shape such as a cylinder or square tube having an opening 201a at one end, and a slide portion 202 and a magnet 203 are slidably accommodated in the inner space. Between the magnet 203 and the bottom 201b of the housing 201, a stroke spring 204 is disposed in an extended state.

  Here, since the stroke spring 204 is a coil spring, and the magnet 203 is disposed in the vicinity thereof, it is preferable to use a nonmagnetic material such as austenitic stainless steel. It is also possible to use an elastic member such as rubber other than the coil spring described above. If the spring constant of the stroke spring 204 is set to be smaller than that of the ejector spring 206, the same mounting operation as in the conventional case can be performed during the buckle mounting operation, and a good buckle mounting feeling can be obtained.

  The magnet 203 is fixed to the slide unit 202 and slides in conjunction with the movement of the slide unit 202. As a material, various permanent magnets such as ferrite, rare earth and neodymium can be used. Moreover, the outer periphery can be coat | covered with a resin mold. In order to detect the movement of the tongue plate 130, the magnet 203 gives a change in magnetic flux density to a magnetic detector disposed in the vicinity by a magnetic field change of the magnet 203 in conjunction with the movement of the tongue plate 130 and the slide portion 202. The magnetizing direction can be either the sliding direction or the direction orthogonal to this, but in this embodiment, as shown in FIG. 3A, the direction perpendicular to the sliding direction, that is, the vertical direction is used. Magnetization direction is set.

  In addition, a bias magnet 212 for applying a bias magnetic field to GMR sensors 210A and 210B described later is provided. The bias magnet 212 is disposed below the GMR sensors 210A and 210B and fixed to the case 14 as shown in FIGS. The magnetization direction is the same as that of the magnet 203 described above, and the GMR sensors 210A and 210B are set to the south pole as shown in FIG. 3 and the like. Therefore, the GMR sensors 210A and 210B have the magnet 203 and the bias. The magnetic flux passes from the magnet 212 in the same direction.

  As shown in FIG. 3 and the like, the bias magnet 212 is relative to the detection region of the GMR sensors 210A and 210B arranged to detect the position state due to the slide movement of the magnet 203 accompanying the movement of the ejector 34 and the slide unit 202. It is set to a predetermined size so as to apply a bias magnetic field. That is, the bias magnet 212 is, for example, a long shape (rod shape) as shown in FIG. 3A, and is formed to a length that covers both detection regions of the arranged GMR sensors 210A and 210B. .

  The GMR sensors 210A and 210B detect a change in the direction of the magnetic field or a change in the magnetic flux density. The resistance values of the GMR sensors 210A and 210B change due to the change of the magnetic field in the surface direction of the resistance chip constituting the GMR sensor. Accordingly, as shown in FIGS. 1 to 3 and the like, in a state where the GMR sensors 210A and 210B are mounted on the substrate 211, the magnetic flux of the magnet 203 crosses the resistance chip inside the GMR sensors 210A and 210B mainly in the surface direction. The substrate is placed in a standing state.

  The positional relationship between the GMR sensors 210A and 210B and the magnet 203 will be described with reference to FIGS. 3 (a) and 3 (b). FIG. 3A is a cross-sectional view of the state detection device showing a state before the tongue plate is inserted into the buckle body (a state where the buckle is not attached). FIG. 3B is a cross-sectional view of the state detection device showing a state where the tongue plate is inserted into the buckle body and the magnet is slid to the lock position (buckle attached state). Here, the position of the magnet 203 when the buckle is not attached as shown in FIG. 3A is set as the first movement position, and the GMR sensor 210A is placed as the first magnetic detector below the first movement position. Has been. Further, the position of the magnet 203 in the buckle-mounted state shown in FIG. 3B is set as a second movement position, and the GMR sensor 210B is placed as a second magnetic detector below the second movement position. Yes.

  Fig.4 (a) is sectional drawing of the state detection apparatus which shows the state before a tongue plate is inserted in a buckle main body (buckle not mounted state). FIG. 4B is a circuit diagram showing a connection state of the GMR sensor, and is a diagram showing a resistance value state when the buckle is not attached. FIG. 4C is a characteristic diagram showing the relationship between the magnetic flux density B and the resistance value R of the GMR sensor, and each GMR sensor in the case where the positional relationship between the magnet and the GMR sensor is that shown in FIG. It is the figure which plotted the resistance value of on the graph. Note that the characteristics shown in FIG. 4C are linear characteristics in the operating range of the GMR sensor because the bias magnetic field by the bias magnet 212 is acting.

  As shown in FIG. 4B, one end of the GMR sensor 210A as the first magnetic detector is connected to the ground (GND), and the other end is connected to the GMR sensor 210B as the second magnetic detector. The other end of the GMR sensor 210B is connected to the power supply side. A connection part between the GMR sensor 210 </ b> A and the GMR sensor 210 </ b> B is used as an output part 220 to output an output signal. As shown in FIG. 4A, a magnet 203 is positioned above the GMR sensor 210A, and thereby magnetic flux passes through the GMR sensor 210A and the resistance value decreases. On the other hand, since the magnetic field from the magnet 203 does not reach the GMR sensor 210B, the resistance value does not change. Therefore, the output signal at the output unit 220 is at the Lo level. When this is plotted, it becomes as shown in FIG. 4C, and the resistance value of the GMR sensor 210A is lower than the resistance value of the GMR sensor 210B by an amount corresponding to the magnetic flux density from the magnet 203.

  Fig.5 (a) is sectional drawing of the state detection apparatus which shows the state (buckle mounting state) after a tongue plate is inserted in the buckle main body. FIG. 5B is a circuit diagram showing the connection state of the GMR sensor, and shows the state of the resistance value when this buckle is attached. FIG. 5C is a characteristic diagram showing the relationship between the magnetic flux density B and the resistance value R of the GMR sensor, and each GMR sensor in the case where the positional relationship between the magnet and the GMR sensor is FIG. 5A. It is the figure which plotted the resistance value of on the graph.

  Here, as shown in FIG. 5A, the magnet 203 is positioned above the GMR sensor 210B, whereby the magnetic flux passes through the GMR sensor 210B and the resistance value decreases. On the other hand, since the magnetic field from the magnet 203 does not reach the GMR sensor 210A, the resistance value does not change. Therefore, the output signal at the output unit 220 is at the Hi level. When this is plotted, it becomes as shown in FIG. 5C, and the resistance value of the GMR sensor 210B is lower than the resistance value of the GMR sensor 210A by an amount corresponding to the magnetic flux density from the magnet 203.

  Therefore, by detecting whether the output at the output unit 220 is Hi level or Lo level, it is easy to determine whether the buckle is not attached as shown in FIG. 4A or the buckle is attached as shown in FIG. Can do.

  In addition to the above GMR sensor, for example, an MR (Magneto Resistance) sensor, a Hall element, or the like can be used as a magnetic detector. As shown in FIG. 2 and the like, the GMR sensors 210A and 210B are attached to the case 14 while being mounted on the substrate 211. The GMR sensors 210A and 210B are attached to the bottom plate 22 in addition to the case 14, for example. May be. The detector unit may be attached to the housing 201 of the buckle switch 2. In this case, the housing 201 includes a magnet 203 as a detection target and GMR sensors 210A and 210B as detectors, and is a detector unit completed only by this. Can be configured.

  Hereinafter, the mechanical operation from the buckle unmounted state to the buckle mounted state will be described. As shown in FIG. 1, a tongue plate 130 is inserted between the side walls 32 from the other end in the longitudinal direction of the bottom plate 22. The tongue plate 130 includes a base portion 132 formed of a metal plate material. The base portion 132 is formed with a slit hole 134 that is long along the opposite direction of the side wall 32 with the tongue plate 130 inserted between the side walls 32, and is a middle portion in the longitudinal direction of the long belt-like webbing belt 140. Is inserted.

  The webbing belt 140 is locked at its base end to a take-up shaft of a webbing take-up device (not shown), and is wound up by a spiral coil spring or the like for urging the take-up shaft in the direction of winding the webbing belt 140. The housing urging force of the shaft urging means acts on the webbing belt 140.

  Further, an insertion plate portion 136 is formed on the base portion 132. The width of the insertion plate portion 136 is smaller than the interval between the side walls 32, and the insertion plate portion 136 of the tongue plate 130 is actually inserted between the side walls 32.

  A through-hole 138 that penetrates in the thickness direction is formed in the insertion plate portion 136. When the insertion plate portion 136 reaches a predetermined position on one end side in the longitudinal direction of the bottom plate 22 between the side walls 32, a latch described later 50 engagement pieces 58 can be penetrated, and the engagement pieces 58 penetrate through the through holes 138, whereby the extraction of the tongue plate 130 from the buckle device 1 is regulated.

  On the other hand, as shown in FIGS. 1 and 2, the buckle device 1 includes a latch 50. The latch 50 includes a base 52. Although it depends on the posture of the latch 50, the base 52 is formed in a flat plate shape that is generally longitudinal in the opposing direction of the side walls 32 and in the thickness direction along the longitudinal direction of the bottom plate 22. Both end portions in the direction enter into support holes 54 as support portions formed on both side walls 32. The base 52 (that is, the latch 50) is supported so as to be rotatable by a predetermined angle with the longitudinal direction of the base 52 as an axial direction until it is interfered with the inner peripheral portion of the support hole 54.

  Further, a flat plate-like connecting portion 56 extends from one end in the width direction of the base portion 52 in the longitudinal direction toward one side in the width direction of the base portion 52, and further, the connecting portion on the opposite side to the base portion 52. An engaging piece 58 extends from 56 toward the bottom plate 22 side.

  The front end 58 a of the engagement piece 58 corresponds to the through hole 60 formed in the bottom plate 22, and the engagement piece 58 can enter the through hole 60 when the latch 50 is displaced.

  As shown in FIGS. 1 and 2, the mounting piece is disposed on the surface of one side (opposite to the bottom plate 22) of the ejector 34 described above corresponding to the tip of the engaging piece 58 of the latch 50. 62 is provided integrally. The urging force from the stroke spring 204 of the buckle switch 2 acts on the ejector 34 as described above.

  When the ejector 34 is located at the position where the external force other than the urging force other than the urging force from the stroke spring 204 is not applied, it faces the tip of the engagement piece 58 along the thickness direction of the bottom plate 22. The mounting piece 62 is provided to do so. The mounting piece 62 moves in the direction of approaching the bottom plate 22 by interfering with the tip of the engagement piece 58 in a state of being opposed to the tip of the engagement piece 58 (that is, movement of the latch 50). To regulate.

  Further, stoppers 64 are extended from both ends in the longitudinal direction of the base 52. The stopper 64 is formed so that the tip side is positioned on the slide trajectory of the ejector 34 against the urging force of the stroke spring 204, and when the ejector 34 slides a predetermined distance against the urging force of the stroke spring 204. 34 contacts the stopper 64.

  Further, a lock member 70 is disposed on the opposite side of the base 20 from the bottom plate 22 via the connecting portion 56 of the latch 50. The lock member 70 includes a base 72. The base 72 has a substantially square bar shape that is formed in the longitudinal direction along the opposing direction of the side walls 32.

  Both end portions of the base portion 72 enter engagement holes 74 formed in the side walls 32. The engagement hole 74 is formed on the other end side in the longitudinal direction of the side wall 32 with respect to the through hole 60, and the base portion 72 is supported on the side wall 32 so as to be rotatable about its own longitudinal direction around the axis. A pair of substantially fan-shaped lock pieces 76 are formed on both ends in the longitudinal direction of the base 72. The lock piece 76 corresponds to a contact piece 78 extending from both ends in the width direction of the connecting portion 56 (latch 50), and the lock piece 76 is in contact with the contact piece 78.

  Further, a contact portion 80 is formed at the longitudinal intermediate portion of the base portion 72. The contact portion 80 contacts the engagement piece 58 in a state where the engagement piece 58 of the latch 50 is separated from the bottom plate 22.

  On the other hand, the buckle device 1 includes a release button 90 as release means. The release button 90 includes a pressing portion 92 for operation. The pressing portion 92 has a plate shape in which the pressing surface faces the other end in the longitudinal direction of the bottom plate 22, and is a longitudinal direction along the opposing direction of the side walls 32.

  Side walls 94 extend from the vicinity of both ends in the longitudinal direction of the pressing portion 92 toward one end in the longitudinal direction of the bottom plate 22. These side walls 94 are opposed to each other along the opposing direction of the side wall 32 described above, and the end opposite to the bottom plate 22 is connected by the top wall 96, and is opened toward the bottom plate 22 as a whole. It is a concave shape.

  Arms 98 extend from the ends of the side walls 94 opposite to the pressing portions 92 so as to face each other along the opposing direction of the side walls 94. Engaging protrusions 100 are formed at the distal ends of both arms 98 toward the other arm 98, and enter the guide holes 102 formed in the side wall 32. The guide hole 102 is a long long hole along the longitudinal direction of the bottom plate 22. The engagement protrusion 100 can be displaced by a predetermined range along the longitudinal direction of the bottom plate 22 by the inner peripheral portion of the guide hole 102, and thereby the movement direction of the release button 90 is changed in the longitudinal direction of the bottom plate 22 by the guide hole 102. It is regulated.

  A stopper 110 is disposed between the pressing portion 92 and the lock member 70. The stopper 110 includes a plate-like base portion 112 that is formed in a longitudinal direction along the opposing direction of the side wall 94. A pair of concave engaging pieces 114 that are open toward the bottom plate 22 when viewed along the longitudinal direction of the base 112 are formed on both ends of the base 112 in the longitudinal direction. The stopper 110 is supported by the lock member 70 by engaging with the base 72 of the lock member 70 described above.

  Further, an interference portion 116 is formed in the vicinity of both engagement pieces 114 of the stopper 110 so as to be able to interfere with the engagement protrusion 100 of the release button 90 described above.

  A compression coil spring 118 is disposed between the stopper 110 and the pressing portion 92 of the release button 90, and one end of the compression coil spring 118 is in contact with the side opposite to the pressing surface of the pressing portion 92. On the other hand, the other end of the compression coil spring 118 is in contact with the base portion 112 of the stopper 110, thereby urging the stopper 110 in the direction of separating from the pressing portion 92.

  In the buckle device 1, when the insertion plate portion 136 of the tongue plate 130 is inserted from the tongue insertion port 18 of the case 14 in the tongue extraction state shown in FIG. 2, as shown in FIG. The front end of the ejector 34 comes into contact with and presses the end of the ejector 34, and slides the ejector 34 toward one end in the longitudinal direction of the bottom plate 22 against the urging force of the stroke spring 204.

  When the ejector 34 slides by a predetermined amount toward one end in the longitudinal direction of the bottom plate 22, the opposed state between the mounting piece 62 of the ejector 34 and the engaging piece 58 of the latch 50 is released, and the ejector 34 moves the stopper 64 of the latch 50. The latch 50 is rotated by pressing.

  As a result, the tip of the engagement piece 58 moves closer to the bottom plate 22. In this state, the through hole 138 of the insertion plate portion 136 and the through hole 60 formed in the bottom plate 22 overlap. Accordingly, in this state, as shown in FIG. 5, the rotated engagement piece 58 passes through the through hole 138 of the insertion plate portion 136 and the through hole 60 of the bottom plate 22.

  Further, when the latch 50 is rotated, the contact state between the engagement piece 58 of the latch 50 and the contact portion 80 of the lock member 70 is released. Here, since the lock piece 76 receives the urging force of the compression coil spring 118 via the stopper 110, the lock member 70 is rotated by the urging force of the compression coil spring 118 so as to be interlocked with the rotation of the latch 50. The piece 76 comes into contact with the contact piece 78 of the latch 50. For this reason, the rotation of the latch 50 in the direction in which the engagement piece 58 is separated from the bottom plate 22 is restricted, and the tongue plate 130 is held in the buckle device 1 to be in the buckle mounted state.

(Effect of the embodiment of the present invention)
When a disturbance magnetic field acts from the outside in the buckle non-attachment state and the buckle attachment state shown above, the resistance values of the GMR sensor 210A and the GMR sensor 210B change. Fig.6 (a) is sectional drawing of the state detection apparatus which shows the state before a tongue plate is inserted in a buckle main body, Comprising: It is a figure which shows the case where an external magnetic field is acting on the downward direction from the top. FIG. 6B is a characteristic diagram showing the relationship between the magnetic flux density B and the resistance value of the GMR sensor. The resistance value R of each GMR sensor when an external magnetic field is applied from the top to the bottom is shown. It is the figure plotted on the graph. Since the magnetic flux generated by the external magnetic field acts in the same direction as the magnetic flux generated by the magnet 203 and the bias magnet 212, both the resistance values of the GMR sensor 210A and the GMR sensor 210B decrease as shown in FIG. However, the influence on both GMR sensors is canceled by the output unit 220, and the output value (Lo level) does not change.

  FIG. 7A is a cross-sectional view of the state detection device showing a state before the tongue plate is inserted into the buckle body, and shows a case where an external magnetic field acts from the bottom upward. is there. FIG. 7B is a characteristic diagram showing the relationship between the magnetic flux density B and the resistance value of the GMR sensor. The resistance value of each GMR sensor when an external magnetic field acts from the bottom to the top is shown as a graph. It is the figure plotted above. Since the magnetic flux generated by the external magnetic field acts in the opposite direction to the magnetic flux generated by the magnet 203 and the bias magnet 212, both the resistance values of the GMR sensor 210A and the GMR sensor 210B increase as shown in FIG. However, the influence on both GMR sensors is canceled by the output unit 220, and the output value (Hi level) does not change.

  In the same manner as described above, the resistance value of each GMR sensor changes even when an external magnetic field is applied from the bottom to the top or from the top to the bottom in the buckle mounted state after the tongue plate is inserted into the buckle body. However, the influence on both GMR sensors is canceled by the output unit 220, and the output value (Hi or Lo level) does not change.

  Due to the effects described above, it is possible to provide a state detection device capable of canceling the influence even when receiving an external magnetic field and performing state detection and a buckle device using the state detection device.

  The embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, although the long thing was used as the bias magnet 212, it can also be set as the structure provided with the separate bias magnet which applies a bias magnetic field to the detection range of each GMR sensor 210A, 210B. This other configuration example is illustrated in FIGS. 8A and 8B in a form corresponding to FIGS. 3A and 3B, respectively. According to this, even when the bias magnet 212 is long, it can be divided like the bias magnets 212A and 212B. In particular, it is effective when the stroke of the buckle wearing state and the non-wearing state is large. Further, even when the substrate 211 on which the GMR sensors 210A and 210B are mounted is horizontally disposed, it is possible to detect a change in magnetic flux density due to a slide change of the magnet 203, and similarly to determine whether the buckle is attached or not. Is possible.

DESCRIPTION OF SYMBOLS 1 ... Buckle device, 2 ... Buckle switch, 14 ... Case, 16 ... Anchor insertion port, 18 ... Tongue insertion port, 20 ... Base, 22 ... Bottom plate, 24 ... Anchor plate, 32 ... Side wall, 34 ... Ejector, 34a ... Press Projection part 36 ... guide hole 50 ... latch 52 ... base part 54 ... support hole 56 ... connecting part 58 ... engagement piece 58a ... tip part 60 ... through hole 62 ... mounting piece 64 ... Stopper 70 ... Lock member 72 ... Base part 74 ... Engagement hole 76 ... Lock piece 78 ... Contact piece 80 ... Contact part 90 ... Release button 92 ... Pressing part 94 ... Side wall 96 ... Upper wall, 98 ... arm, 100 ... engagement protrusion, 102 ... guide hole, 110 ... stopper, 112 ... base, 114 ... engagement piece, 116 ... interference part, 118 ... compression coil spring, 130 ... tongue plate, 132 ... Base, 13 ... Slit hole, 136 ... Insertion plate part, 138 ... Through hole, 140 ... Webbing belt, 201 ... Housing, 201a ... Opening part, 201b ... Bottom part, 202 ... Slide part, 203 ... Magnet, 204 ... Spring for stroke, 206 ... Ejector spring, 210A, 210B ... GMR sensor, 211 ... substrate, 212 ... bias magnet, 220 ... output unit

Claims (5)

A housing,
A slide portion supported movably by the housing;
A permanent magnet that moves in conjunction with the slide part;
A first magnetic detector disposed corresponding to a first movement position of the permanent magnet;
A second magnetic detector disposed corresponding to the second movement position of the permanent magnet and connected in series with the first magnetic detector;
A bias magnet for applying a bias magnetic field to the first and second magnetic detectors,
A state detection device that detects an output at the connection portion of the first magnetic detector and the second magnetic detector as a position state in which the permanent magnet moves.   The state detection apparatus according to claim 1, wherein the first and second magnetic detectors are GMR (Giant Magneto Resistance) sensors. A device main body capable of inserting and holding a tongue plate provided on a webbing of a vehicle seat belt device;
The state detection device according to claim 1 or 2 placed in the device main body,
A buckle device comprising: A device main body capable of inserting and holding a tongue plate provided on a webbing of a vehicle seat belt device;
A slide part movably supported in the apparatus body;
A permanent magnet that moves in conjunction with the slide part;
A first magnetic detector disposed corresponding to a first movement position of the permanent magnet;
A second magnetic detector disposed corresponding to the second movement position of the permanent magnet and connected in series with the first magnetic detector;
A bias magnet for applying a bias magnetic field to the first and second magnetic detectors,
A buckle device that detects an output at the connecting portion of the first magnetic detector and the second magnetic detector as a moving state of the permanent magnet. The buckle device according to claim 4, wherein the first and second magnetic detectors are GMR sensors.

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