JP2008197021A - Seat with load fluctuation detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To highly sensitively detect load fluctuation by simple structure, using a torsion bar. <P>SOLUTION: This seat is provided with the torsion bars 112, 113 of changing a twist angle by the load fluctuation, and a reference bar 120 not distorted by the load fluctuation, excites collectively the torsion bars 112, 113 and the reference bar 120 by an exciting coil 121 wound around the periphery thereof, and outputs a difference between a voltage value output from the first pickup coil 112a wound around the torsion bars 112, 113, and a voltage value output from the second pickup coil 120a wound around the reference bar 120. The seat is arranged with load fluctuation detectors provided with the torsion bars 112, 113 and the reference bar 120 in two portions in the vicinity of front end and in the vicinity of the rear end of a seat cushion part, and a load of a person supported by the seat cushion part is accurately measured irrespective of a seating posture, by adding load values obtained from the respective load fluctuation detectors. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a seat with a load fluctuation detection device using a torsion bar whose torsion angle changes due to load fluctuation.

For example, in order to automatically switch the operation control of an air bag, as a technique for automatically distinguishing whether an occupant seated on a seat is an adult or a child and feeding it back to the operation control unit of the air bag, A sheet having a mechanism for automatically detecting the above is known. Normally, urethane foam is used as a cushioning material, so it is possible to detect the weight by measuring the amount of displacement of a coil spring that supports the urethane foam and is arranged vertically on the vehicle body floor, and the magnitude of the amount of displacement. Has been done. On the other hand, the present applicant, as Patent Document 1, elastically supports the cushion material provided in the seat cushion portion by a torsion bar disposed in the seat cushion portion, and incorporates a load fluctuation detection device in the torsion bar. The technology is disclosed. Specifically, the pickup coil is wound around the torsion bar, and a reference bar (magnetic bar member) that is not distorted by load fluctuation is provided. The pickup coil is also wound around the reference bar, and the difference between the induced voltages obtained from the two coils. This is a technique for calculating the load and detecting the load fluctuation.
JP 2005-345257 A

  In Patent Document 1, the load fluctuation detection device is only provided near the rear end of the seat cushion portion. For this reason, the load changes depending on the seating position of the person, and there is a problem in terms of accurate load detection.

  This invention is made | formed in view of said point, and makes it a subject to provide the sheet | seat with a load fluctuation detection apparatus which improved the measurement precision more.

In order to solve the above-described problem, the present invention according to claim 1 includes a torsion bar disposed along the width direction in the vicinity of the front end and the rear end of the seat cushion portion, and the torsion angle is changed by load fluctuation. With
Corresponding to each torsion bar, a reference bar made of a magnetic material that is not distorted by the load variation is disposed,
An excitation coil wound around each of the pair of the torsion bar and reference bar disposed near the front end or near the rear end, and a first pickup coil wound around the torsion bar And a second pickup coil wound around the reference bar,
A seat with a load fluctuation detecting device, comprising: difference output means for outputting a difference between output values of the first pickup coil and the second pickup coil disposed near the front end or the rear end. I will provide a.
In the present invention according to claim 2, the first arm member is provided at each end portion of the torsion bar disposed near the front end so as to protrude obliquely upward and forward from the position where the torsion bar is disposed. A front end support frame is provided between the first arm members, and
A second arm member is provided at each end of the torsion bar disposed in the vicinity of the rear end so as to protrude obliquely downward and rearward from the position where the torsion bar is disposed. A rear end support frame is spanned between the members,
The seat with a load variation detection device according to claim 1, wherein a cushioning material is stretched between the front end support frame and the rear end support frame.
According to a third aspect of the present invention, there is provided the seat with a load variation detecting device according to the second aspect, wherein the cushion material is a three-dimensional solid knitted fabric.

  The present invention includes a torsion bar whose torsion angle changes due to load fluctuations, and a reference bar which does not distort due to load fluctuations, and the torsion bar and the reference bar are collectively excited by an exciting coil wound around them. It is a structure that outputs the difference between the voltage value output from the first pickup coil wound around the bar and the voltage value output from the second pickup coil wound around the reference bar. . Therefore, it is possible to detect a slight fluctuation of the torsion angle of the torsion bar with high sensitivity. At this time, in the present invention, the load fluctuation detection devices including the torsion bar and the reference bar are arranged at two locations near the front end and the rear end of the seat cushion portion, and the load value obtained from each load fluctuation detection device. Is added, the load of the person supported by the seat cushion portion can be measured more accurately regardless of the sitting posture.

  Hereinafter, the present invention will be described in more detail based on embodiments shown in the drawings. 1 to 3 are views showing a vehicle seat 100 according to an embodiment of the present invention.

  The seat 100 includes a cushion frame 110 and a back frame 150. The cushion frame 110 includes side frames 111 and 111, and torsion bars 112 and 113 constituting a load fluctuation detecting device are provided in the width direction near the front end and the rear end, respectively. First arm members 114 and 115 are provided at each end portion of one torsion bar 112 disposed near the front end so as to protrude obliquely upward and forward from the position where the one torsion bar 112 is disposed. The front end support frame 116 is stretched between the first arm members 114 and 115.

  The second arm extends from the position of the other torsion bar 113 obliquely downward and rearward to the end of the other torsion bar 113 disposed near the rear end of the side frames 111 and 111. Members 117 and 118 are provided, and a rear end support frame 119 is spanned between the second arm members 117 and 118.

  A base net material 140 made of a two-dimensional cloth material or a three-dimensional solid knitted fabric is stretched between the front end support frame 116 and the rear end support frame 119. Above the base net material 140, a cushion material such as a three-dimensional solid knitted fabric is stretched over the side frames 111 and 111 so as to cover the entire base net material 140. Since the front end support frame 116 and the rear end support frame 119 arranged in this way both swing back and forth when external vibration is input, the external vibration can be efficiently damped. In addition, since the front end support frame 116 located at the front portion of the seat cushion portion 110 can be rotated forward with one torsion bar 112 as a fulcrum, the pedal movement corresponds to the knee movement direction when the pedal is operated. The feeling of hitting the front edge at times is reduced, improving comfort and sitting comfort.

  In the present embodiment, the load fluctuation detection device 1 is disposed at two locations near the front end and the rear end. As shown in FIGS. 4 to 6, the load fluctuation detection device 1 is arranged in parallel with the one torsion bar 112 (or the other torsion bar 113) and the torsion bar 112 (or the other torsion bar 113). And a reference bar 120 provided. One torsion bar 112 and the other torsion bar 113 are used when a load fluctuation occurs, such as when sitting or when external vibration is input, or when body movement occurs due to breathing or the like. The twist angle changes via the net member 140, the front end support frame 116, and the rear end support frame 119. On the other hand, the reference bar 120 is arranged so as not to be twisted, that is, not distorted even if such load fluctuation occurs. As long as the reference bar 120 is not distorted by the load fluctuation, the reference bar 120 may not be arranged in parallel with the one torsion bar 112 (or the other torsion bar 113). It can be obtained, but it contributes to space saving by arranging in parallel as shown in the figure. The reference bar 120 may be functionally shorter than the torsion bars 112 and 113, and the reference bar 120 and a part of the torsion bars 112 and 113 are accommodated in the storage case 130.

  Specifically, as shown in FIGS. 5 and 6, a first pickup coil 112 a is wound around in one direction around the torsion bars 112 and 113, and around the reference bar 120. A second pickup coil 120a is provided that is wound in the opposite direction to the first pickup coil 112a. And the exciting coil 121 is wound around these.

  According to the present embodiment, an induction current is passed through the exciting coil 121 from an AC power source (not shown). As shown in FIG. 3, when a person is seated, the first arm members 114 and 115, the front end support frame 116 supported by the first arm members 114 and 115, and the second arm members 117 and 118 and the support are supported by the first arm members 114 and 115. Each of the rear end support frames 119 thus displaced is displaced from the solid line position to the broken line position. Specifically, the first arm members 114 and 115 and the front end support frame 116 supported by the first arm members 114 and 115 are displaced obliquely upward and rearward around the one torsion bar 112, and the second arm members 117 and 118 are displaced. The rear end support frame 119 supported by this is displaced obliquely forward and downward about the other torsion bar 113.

  As a result, the torsion angles of the torsion bars 112 and 113 change, and a predetermined induced voltage is output from each first pickup coil 112a. A difference between the output value and the output value from each second pickup coil 120a is calculated by a difference output means comprising a control circuit. Then, for example, the load is specified by comparing the difference between the output voltage values with a table or graph in which the correlation between the voltage value and the load is taken. In the present embodiment, the load fluctuation detection device 1 is disposed at two locations near the front end and the rear end of the seat cushion portion 110. Therefore, the output voltage value is obtained from the two load fluctuation detection devices 1. For this reason, for example, when the load obtained from the load fluctuation detecting device 1 arranged near the front end is 5 kg and the load obtained from the load fluctuation detecting device 1 arranged near the rear end is 10 kg, the total of both is 15 kg. It can be determined that the load is applied, and can be used for various controls (such as airbag operation control) commensurate with the total load.

FIG. 1 is a perspective view showing a schematic configuration of a seat to which a load variation detection device according to one embodiment of the present invention is attached. FIG. 2 is a side view showing a schematic configuration of the sheet according to the embodiment. FIG. 3 is a side view for explaining the operation of the sheet according to the embodiment. FIGS. 4A and 4B are views showing the external appearance of the load variation detecting device used in the embodiment, wherein FIG. 4A is a perspective view and FIG. FIG. 5 is a diagram illustrating a specific configuration of the load variation detection device according to the embodiment. 6 is a cross-sectional view taken along line AA in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Load fluctuation detection apparatus 100 Seat 110 Cushion frame 112 One torsion bar 113 Other torsion bar 116 Front end part support frame 119 Rear end part support frame 120 Reference bar 112a First pickup coil 120a Second pickup coil 121 Excitation coil 140 Basenet 150 Back frame

Claims (3)

A torsion bar is provided near the front end and the rear end of the seat cushion portion along the width direction, and the torsion angle changes depending on the load variation.
Corresponding to each torsion bar, a reference bar made of a magnetic material that is not distorted by the load variation is disposed,
An excitation coil wound around each of the pair of the torsion bar and reference bar disposed near the front end or near the rear end, and a first pickup coil wound around the torsion bar And a second pickup coil wound around the reference bar,
A seat with a load fluctuation detecting device, comprising: difference output means for outputting a difference between output values of the first pickup coil and the second pickup coil disposed near the front end or the rear end. . A first arm member is provided at each end of the torsion bar disposed in the vicinity of the front end so as to protrude obliquely upward and forward from the position where the torsion bar is disposed. Between the front end support frame,
A second arm member is provided at each end of the torsion bar disposed in the vicinity of the rear end so as to protrude obliquely downward and rearward from the position where the torsion bar is disposed. A rear end support frame is spanned between the members,
The seat with a load variation detecting device according to claim 1, wherein a cushion material is stretched between the front end support frame and the rear end support frame.   The seat with a load variation detecting device according to claim 2, wherein the cushion material is a three-dimensional solid knitted fabric.

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