JP5438718B2 - Seat belt device - Google Patents

Description

  The present invention relates to a seat belt device that restrains an occupant seated on a vehicle seat by webbing.

  In a seat belt device mounted on a vehicle, an occupant restraining webbing is wound around a bobbin (also referred to as a belt reel or a spindle) in a retractor, and is pulled out of the retractor when mounted. In this type of seat belt device, a rotating shaft projects from one end of a bobbin, and the rotating shaft is urged to rotate by a take-up spring.

  In recent years, a seat belt apparatus of this type has been developed in which a motor is connected to a rotating shaft of a bobbin via a clutch, and webbing slack removal and emergency pull-in are performed with the power of the motor (for example, Patent Document 1 and Patents). Reference 2).

  Such a seat belt device is provided with a clutch for connecting / disconnecting motor power to a rotating shaft protruding from the bobbin, and between the clutch and the take-up spring, the bobbin rotation state (rotation direction and rotation amount, A rotation detecting means for detecting a rotation speed or the like is provided. The detection result of the rotation detection means is output to a motor control controller.

  The rotation detection means includes a magnetic rotating body (magnetic disk) having different magnetism according to the position in the circumferential direction, and a magnetic sensor such as a Hall element that detects a magnetic change according to the rotation of the magnetic rotating body. The magnetic rotating body is integrally attached at a position between the clutch and the winding spring on the rotating shaft of the bobbin. The magnetic sensor is disposed in non-contact with the magnetic rotating body.

  In the above configuration, when the bobbin rotates according to the webbing withdrawal or winding, the magnetic rotating body rotates integrally with the bobbin, and the magnetic change around the magnetic rotating body at that time is transmitted to the non-contact type magnetic sensor. The rotation state is detected.

JP 2008-238866 A JP 2000-335368 A

  As described in Patent Document 1, the webbing is often configured to be drawn upward from the retractor. Therefore, the belt reel winding the webbing receives an upward force that is the pulling-out direction while the webbing is pulled out. However, if there is even a slight play on the rotation axis of the belt reel, the belt reel that receives the upward force during webbing pulling out slightly rises, and when pulling is completed, it lowers due to gravity and returns to its original state. That is, the belt reel rattles.

  Even with such slight backlash, the distance between the magnetic rotating body (magnetic disk) and the non-contact magnetic sensor installed in the radial direction away from the circumference changes. This may adversely affect the detection accuracy of the bobbin rotation state, even if it does not deviate from the specification.

  According to Patent Document 2, the detection direction of the sensor element is perpendicular to the connection disk (magnetic rotating body). Therefore, even if rattling occurs, the distance between the sensor element and the connecting disk does not change, and there is no adverse effect on the detection accuracy as in Patent Document 1. However, in order to accurately detect the rotation state of the connecting disk, a large number of sensor elements must be arranged around the connecting disk in the thickness direction (the above-described vertical direction). In such a configuration, an increase in the size and cost of the apparatus is inevitable.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a seat belt device that can detect the rotational state of the bobbin with high accuracy even when the webbing is pulled out.

  In order to solve the above problems, a representative configuration of a seat belt device according to the present invention includes a bobbin that winds up webbing, a substantially disk-shaped rotor connected to a rotating shaft of the bobbin, and a periphery of the rotor. And a non-contact type sensor that detects the rotational state of the rotor, and the sensor is disposed in a radial direction of the rotor and substantially perpendicular to the direction in which the webbing is pulled out from the bobbin. It is characterized by being.

  In the above configuration, if the seat belt device is installed in the vehicle body so that the webbing is pulled out upward, the rotation axis of the bobbin extends in a substantially horizontal direction, and the bobbin is rattled up and down. However, it is possible to detect the rotation state of the bobbin with high accuracy even when the webbing is pulled out without being affected by the looseness of the bobbin.

  This is because according to the present invention, the non-contact sensor is installed at a height substantially equal to the rotation axis of the bobbin. In other words, in the present invention, the sensor is arranged in the horizontal direction (either left or right of the rotor) that forms an angle of approximately 90 degrees with the webbing pull-out direction. Therefore, even if the bobbin rattles up and down, the change in the distance between the rotor and the sensor is small, and there is almost no influence on the detection accuracy of the bobbin rotation state.

  The rotating shaft of the bobbin may extend substantially in the vehicle length direction or the vehicle width direction.

  According to the present invention, it is possible to provide a seat belt device that can detect the rotational state of the bobbin with high accuracy even when the webbing is pulled out.

1 is an exploded view of an embodiment of a seat belt device according to the present invention. FIG. 2 is a partially enlarged view of the seat belt device of FIG. 1 after assembly. FIG. 2 is an exploded view of the Hall element case of FIG. 1. It is a figure which illustrates the seatbelt apparatus which is a comparative example with FIG.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(Seat belt device 100)
FIG. 1 is an exploded view of an embodiment of a seat belt device 100 according to the present invention. FIG. 2 is a partially enlarged view of the seat belt device 100 of FIG. 1 after assembly. 2A is a front view of the magnetic ring 124 of FIG. 1, and FIG. 2B is a cross-sectional view taken along the line AA of FIG. 1 and FIG. The seat belt device (retractor) 100 includes a bobbin (also referred to as a spindle or a belt reel) 106 (see FIG. 2B) for winding webbing. The bobbin 106 is rotatably supported by a retractor frame (not shown), and the rotating shaft 110 of the bobbin 106 protrudes to the outside.

  As illustrated in FIG. 2, the rotating shaft 110 of the bobbin 106 is connected to a latch ring 108 and a gear mechanism 109 included in the power transmission unit 116. The latch ring 108 is connected to the motor 118 via a gear mechanism 109 so that the power from the motor 118 is connected and disconnected.

  The power transmission unit 116 is provided with a rotating shaft 120 that protrudes coaxially to the rotating shaft 110 of the bobbin 106. The latch ring 108 in the power transmission unit 116 connects the motor 118 and the rotating shaft 120 (bobbin 106) only when the motor 118 is driven. The latch ring 108 is also configured to disconnect the connection between the motor 118 and the rotating shaft 120 (bobbin 106) when the motor 118 is in a non-driven state. The casing 122 of the power transmission unit 116 that accommodates the latch ring 108 and the gear mechanism 109 is formed of a resin material.

  A magnetic disk (magnetic rotating body) 126 having a magnetic ring 124 on the outer periphery is connected to the front end portion of the rotating shaft 120 as a substantially disk-shaped rotor. The magnetic disk 126 is always connected to the bobbin 106 via the latch ring 108, and rotates at an angular velocity equal to that of the bobbin 106 in close cooperation with the bobbin 106. A connecting shaft 128 projects from the axial center position of the magnetic disk 126. As illustrated in FIG. 2A, the magnetic ring 124 is magnetized so that different magnetic poles of N pole / S pole appear alternately along the circumferential direction, and the magnetism is magnetized according to the position in the circumferential direction. Is different.

  The seat belt device 100 includes a winding spring 134. The winding spring 134 is coupled to a connecting shaft 128 that is integral with the magnetic disk 126, and urges the bobbin 106 to rotate in the webbing winding direction. The winding spring 134 is constituted by a spring, and the inner peripheral end thereof is coupled to the connecting shaft 128, while the outer peripheral end is coupled to the inner wall of the front cover 136 of the seat belt device 100. The front cover 136 is combined with the rear cover 137 and accommodates the magnetic disk 126 and the winding spring 134 in the internal space.

  FIG. 3 is an exploded view of the Hall element case 148 of FIG. A substrate 141 mounted with a pair of Hall elements 130A and 130B (magnetic sensor) is held in a resin Hall element case 148 having a substantially arc shape. In addition, a harness 149 that connects a sensor circuit formed on the substrate 141 to the outside, a Zener diode 151 and a capacitor 153 that configure the sensor circuit, a yoke 155 that guides the harness 149, and the like are mounted on the substrate 141. The Hall element case 148 including the substrate 141 is disposed in the sensor installation space 146 in the rear cover 137 as illustrated in FIG.

  Therefore, when the seat belt device 100 of FIG. 1 is assembled, as schematically shown in FIG. 2A, a pair of Hall elements 130A and 130B spaced apart in the circumferential direction are formed outside the periphery of the magnetic disk 126. The magnetic disk 126 is arranged in a non-contact but close proximity. The Hall elements 130A and 130B are non-contact sensors that detect the rotation state of the magnetic disk 126, that is, the rotation state of the bobbin 106.

  The pair of Hall elements 130A and 130B are connected to a controller (not shown) via a signal processing sensor circuit mounted on the substrate 141. Although the rotation state of the bobbin 106 is detected by this controller, the principle is as described in Patent Document 1, for example, and is omitted.

(Arrangement of Hall elements 130A and 130B)
A feature of the present embodiment is that the Hall elements 130A and 130B are in the radial direction of the magnetic disk 126, and the webbing (not shown) is substantially orthogonal to the direction 157 in which the webbing (not shown) is pulled out from the bobbin 106 (left side in FIG. 2A). ). In this embodiment, the Hall elements 130A and 130B are provided only on the left side of the magnetic disk 126 as described above. However, the Hall elements 130A and 130B may be provided only on the right side of the magnetic disk 126. May be provided.

  In the above configuration, if the direction 157 in which the webbing is pulled out is the upward direction, the rotation shaft 110 of the bobbin 106 extends in a substantially horizontal direction, and the bobbin 106 has a vertical play along the direction 157. However, the Hall elements 130A and 130B can detect the rotation state of the bobbin 106 with high accuracy even when the webbing is pulled out without being affected by the backlash of the bobbin 106.

  This is because according to the present embodiment, the non-contact Hall elements 130A and 130B are installed at a height substantially equal to the rotation shaft 110 of the bobbin 106. In other words, in the present embodiment, the Hall elements 130A and 130B are arranged in the horizontal direction (one of the left and right sides of the magnetic disk 126) that forms an angle of approximately 90 degrees with the webbing pull-out direction 157. Therefore, even if the bobbin 106 rattles up and down, the change in the distance D1 between the magnetic disk 126 and the Hall elements 130A and 130B is small, and the Hall elements 130A and 130B can stably receive the magnetic force from the magnetic disk 126. Therefore, there is almost no influence on the detection accuracy of the rotation state of the bobbin 106.

  The Hall elements 130A and 130B need to be separated in the circumferential direction on the principle of detecting the rotation state of the bobbin 106. Therefore, as described as “substantially 90 degrees”, the Hall elements 130A and 130B are not necessarily arranged in the horizontal direction that forms an angle of 90 degrees strictly with the webbing pull-out direction 157. It is desirable that both of the Hall elements 130A and 130B are arranged in a range that forms an angle of about 90 ° ± 20 ° with the webbing pull-out direction 157.

  FIG. 4 is a view illustrating a seat belt device 10 which is a comparative example with FIG. Compared to this embodiment, in the seat belt device 10 of the comparative example, the Hall elements 130A and 130B are arranged at positions along the webbing pull-out direction 157 (below the magnetic disk 126). In this case, since there is play G1, G2 between the connecting shaft 128 of the magnetic disk 126 and the front cover 136, the bobbin 106 rattles up and down, so that the distance D2 between the magnetic disk 126 and the Hall elements 130A, 130B. May change, and the detection accuracy of the rotation state of the bobbin 106 may be adversely affected. This is because the magnetic disk 126 and the Hall elements 130A and 130B are arranged along the direction 157 in which the webbing is pulled out, that is, the direction of gravity in which the bobbin 106 rattles.

  The rotating shaft 110 of the bobbin 106 may extend substantially along either the vehicle length direction or the vehicle width direction. In the former case, the Hall elements 130A and 130B are arranged in the vehicle width direction when viewed from the center of the magnetic disk 126. In the latter case, the Hall elements 130A and 130B are arranged in the vehicle length direction (vehicle longitudinal direction) when viewed from the center of the magnetic disk 126. Either the former or the latter may be used, but it is preferable that the rotating shaft extends in the vehicle length direction and the front and back surfaces of the webbing face the vehicle left and right as in the former. In the latter case, it is necessary to twist the drawn webbing about 90 degrees and pass it through a through anchor (not shown).

  In the present embodiment, the rotation state of the spindle is detected in a non-contact manner using the Hall elements 130A and 130B. However, the present embodiment can be applied to any type of sensor as long as it is a non-contact type sensor that detects the rotation state of the magnetic disk 126. For example, a sensor using a medium or method such as RF-ID (IC tag), infrared light, or light can be considered.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings. However, the embodiments described above are preferred examples of the present invention, and other embodiments can be implemented by various methods. Can be carried out. The invention is not limited to the detailed shape, size, configuration, and the like of the components shown in the accompanying drawings unless otherwise specified in the present specification. In addition, expressions and terms used in the present specification are for the purpose of explanation, and are not limited thereto unless otherwise specified.

  Therefore, it is obvious for those skilled in the art that various changes and modifications can be conceived within the scope of the claims, and these naturally belong to the technical scope of the present invention. It is understood.

  INDUSTRIAL APPLICABILITY The present invention can be used for a seat belt device that restrains an occupant seated on a vehicle seat by webbing.

DESCRIPTION OF SYMBOLS 100 ... Seat belt apparatus 106 ... Bobbin 108 ... Latch ring 109 ... Gear mechanism 110 ... Rotating shaft 116 ... Power transmission unit 118 ... Motor 122 ... Casing 124 ... Magnetic ring 126 ... Magnetic disk 128 ... Connecting shaft 130A, 130B ... Hall element 134 ... take-up spring 136 ... front cover 137 ... rear cover 141 ... substrate 146 ... sensor installation space 148 ... Hall element case 149 ... harness 151 ... Zener diode 153 ... capacitor 155 ... yoke

Claims (2)

A bobbin that winds up the webbing;
A substantially disk-shaped rotor connected to the rotating shaft of the bobbin;
A non-contact sensor that is disposed outside the periphery of the rotor and detects a rotation state of the rotor;
The seat belt device according to claim 1, wherein the sensor is disposed in a radial direction of the rotor and in a direction substantially orthogonal to a direction in which the webbing is pulled out from the bobbin.   The seat belt device according to claim 1, wherein the rotation axis of the bobbin extends substantially in a vehicle length direction or a vehicle width direction.

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