JP2006177676A - Displacement detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet load detector for preventing foreign matters, such as fine particles, from entering into the gap between a Hall element and a magnet in a displacement detector, using a displacement sensor comprising the Hall element and the magnet. <P>SOLUTION: In the displacement detector, having the Hall element 22 at a first member and the magnet 23 at a second member for detecting the relative displacement between the first and second members, a medium 40, having deformation capacity, is filled into the gap between the Hall element 22 and the magnet 23. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a displacement detection device that detects a relative displacement between two members. More specifically, the present invention relates to a displacement detection device that is used for a seat of an automobile or the like and detects a relative displacement between a movable arm and a fixed arm when a seated person is seated on the seat.

  2. Description of the Related Art Conventionally, when an occupant sits on a vehicle seat such as an automobile, a seat belt holding function and an airbag operating function are appropriately controlled by detecting a load from the occupant. Such load detection is performed by a displacement detection device attached to the seat.

  As a conventional displacement detection device, there has been a load detection device using a displacement sensor composed of a Hall element and a magnet (see, for example, Patent Document 1). In the load detection device of Patent Document 1, a magnet is installed on a member (movable arm) on the seat side, and a hall element is installed on a member (fixed arm) on the floor side. Here, when a person is seated on the seat, the movable arm is displaced with respect to the fixed arm, whereby the magnetic flux density of the magnetic field from the magnet to the Hall element changes, and this change in magnetic flux density is detected as a change in the electrical signal. The displacement is detected by doing so.

JP 2003-97998 A

  In a displacement detection device using a displacement sensor composed of a Hall element and a magnet as in Patent Document 1, it is important to protect the space between the Hall element and the magnet from the outside. However, foreign matter such as dust may be brought in from the outside due to people getting in and out of the vehicle where the displacement detection device is installed, and if such foreign matter enters the gap between the Hall element and the magnet, a magnetic field is generated. As a result, the displacement cannot be detected accurately. In addition, if a foreign object is caught in the gap between the Hall element and the magnet, the relative displacement between the movable arm and the fixed arm, that is, the relative displacement between the Hall element and the magnet is hindered, and the displacement detection itself cannot be performed. Can happen.

  The present invention has been made in view of the above-described problems, and the object of the present invention is to provide a displacement detection device that uses a displacement sensor composed of a Hall element and a magnet. It is in the point which provides the seat load detection apparatus which can prevent entering.

  A characteristic configuration of the displacement detection device according to the present invention is a displacement detection in which a Hall element is provided in the first member and a magnet is provided in the second member in order to detect relative displacement between the first member and the second member. In the apparatus, the gap between the Hall element and the magnet is filled with a medium having deformability.

  In the displacement detection device of this configuration, the gap between the Hall element and the magnet is filled with a medium having deformability, so that foreign matters such as dust can be prevented from entering the gap. For this reason, there is a risk that the magnetic field from the magnet that causes detection error to the Hall element may be disturbed, or the relative displacement between the first member and the second member, that is, the relative displacement between the Hall element and the magnet may be hindered. There is no.

  In addition, since the medium to be filled has a deformability, when the Hall element and the magnet are relatively displaced, the medium itself can be fluidly deformed to follow, and the filled state of the gap can be maintained.

  Thus, with the displacement detection device of this configuration, the gap between the Hall element and the magnet is always protected from the outside, so that accurate displacement detection can be performed over a long period of time.

  In the displacement detection device of the present invention, the medium may be a gel substance.

  In the displacement detection device of this configuration, the medium that fills the gap between the Hall element and the magnet is a gel substance. Since the gel-like substance is excellent in fluidity, the resistance is not so great when the Hall element and the magnet are relatively displaced. For this reason, while ensuring a smooth relative displacement between the Hall element and the magnet, the gap between the Hall element and the magnet can be protected and the displacement detection can be stabilized over a long period of time.

  In the displacement detection device of the present invention, a rust inhibitor may be included in the medium.

  In the displacement detection device of this configuration, the rust preventive agent contained in the medium prevents the occurrence of rust in the vicinity of the filled portion of the medium, so the product life of the displacement detection device is extended and the displacement detection is stable over a long period of time. Can be performed.

  In the displacement detection device of the present invention, it is also possible to provide a boot made of a flexible material covering the gap from the first member to the second member.

  In the displacement detection device of this configuration, the boot made of a flexible material provided from the first member to the second member can reliably prevent foreign matter from entering the gap between the Hall element and the magnet. The reliability of the displacement detection device is further improved, and accurate displacement detection is possible over a long period of time. In addition, since the boot is made of a flexible material, the boot is easily deformed with respect to the relative displacement between the Hall element and the magnet, and does not become a great resistance for the displacement operation between the Hall element and the magnet. .

  A characteristic configuration of the displacement detection device for an automobile according to the present invention is such that a Hall element or a magnet is provided on the fixed arm in order to detect a relative displacement between the fixed arm attached to the vehicle floor and the movable arm attached to the seat. A displacement detection device for an automobile comprising one of the above, wherein the movable arm is provided with the other of the hall element and the magnet, and a gap between the hall element and the magnet is filled with a medium having deformability. It is in a certain point.

  In the automobile displacement detection apparatus of this configuration, the gap between the Hall element and the magnet is filled with a medium having deformability, so that foreign matters such as dust can be prevented from entering the gap. For this reason, there is no possibility that the magnetic field from the magnet that causes detection error to the Hall element is disturbed, or that the relative displacement between the fixed arm and the movable arm, that is, the relative displacement between the Hall element and the magnet is not disturbed. . Therefore, the gap between the Hall element and the magnet is always protected, and accurate displacement detection is possible over a long period of time.

  In addition, since the displacement detection device for an automobile of this configuration can be optimally used for detecting the displacement of an automobile seat, for example, a foreign matter or the like falls on the displacement detection device and gets stuck in the gap between the hall element and the magnet. Therefore, a highly reliable device can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a state in which a displacement detection device 100 of the present invention is attached to a vehicle seat 10. The seat 10 includes a seat cushion 10a and a seat back 10b, and is installed on a floor 11 of the vehicle via a seat rail 12. The seat rail 12 is slidably engaged with an upper frame 13 constituting a base portion on the seat 10 side. The upper frame 13 supports the cushion frame 14 of the seat 10. The displacement detection device 100 is attached between the upper frame 13 and the cushion frame 14.

  FIG. 2 is a perspective view of the displacement detection device 100. The displacement detection device 100 shown here is attached to the rear side of the seat 10, but the one attached to the front side of the seat 10 can also have the same configuration.

  The displacement detection device 100 detects the relative displacement between the two members, that is, the first member and the second member. In the present embodiment, the first member is described as the fixed arm 15 installed on the floor 11 side, and the second member is described as the movable arm 16 installed on the seat 10 side.

  FIG. 3 is a diagram illustrating details of the displacement detection apparatus 100. 3A is a front view of the displacement detection device 100, and FIG. 3B is a cross-sectional view taken along line SS ′ of FIG. 3A. Hereinafter, the displacement detection apparatus 100 of the present embodiment will be specifically described.

(Fixed arm)
A hall element 22 is attached to the fixed arm 15 attached to the upper frame 13 via the first holder 20. This Hall element 22 functions as a displacement sensor by combining with a magnet 23 described later. Further, the first holder 20 that holds the Hall element 22 can be attached to the fixed arm 15 by the first screw 25. At this time, the first screw hole 26 of the first screw 25 provided in the fixed arm 15 can have a long hole shape in order to finely adjust the mounting position of the first holder 20. Further, in order to prevent excessive movement of the cushion frame 14, the fixing arm 15 incorporates a regulating means 19 including a regulating member 19 a and a regulating hole 19 b.

(Movable arm)
The movable arm 16 is provided in parallel with the fixed arm 15. A magnet 23 is attached to the movable arm 16 via a second holder 21. The magnet 23 is disposed so as to face the hall element 22 on the fixed arm 15 side. The second holder 21 that holds the magnet 23 can be attached to the movable arm 16 by the second screw 30. At this time, the second screw hole 31 of the second screw 30 provided in the second holder 21 can have a long hole shape in order to finely adjust the mounting position of the second holder 21.

  The movable arm 16 is connected to the cushion frame 14 by a connecting member 18. With such a configuration, when a person sits on the seat 10, the seat load is transmitted from the cushion frame 14 to the movable arm 16 via the connecting member 18. The connecting member 18 is rotatable with the movable arm 16 so as to allow variation in the direction in which the seat load acts on the movable arm 16.

  Further, the movable arm 16 is connected in parallel by the fixed arm 15 and the torsion bar 17 having the torsional axis X. The torsion bar 17 is elastically rotationally displaced with respect to the torsional force. Then, due to the rotational displacement of the torsion bar 17, the magnet 23 held by the second holder 21 attached to the movable arm 16 corresponds to the Hall element 22 held by the first holder 20 attached to the fixed arm 15. Relative displacement. Note that the torsional rigidity of the torsion bar 17 is appropriately set in consideration of measurement accuracy and the like.

(Displaceable medium)
Next, a displaceable medium used in the displacement detection device 100 of the present embodiment will be described.

  As shown in FIG. 3, the hall element 22 on the fixed arm 15 side and the magnet 23 on the movable arm 16 side are arranged to face each other with a gap D of a predetermined distance. The predetermined distance is set such that a magnetic field generated from the magnet 23 can be detected by the Hall element 22.

  A cylindrical or square cylindrical housing 27 is attached to the first holder 20 that holds the Hall element 22 so as to surround the second holder 21. Here, the distance between the inner surface of the housing 27 and the second holder 21 is a distance that allows the maximum displacement amount of the movable arm 16, that is, a state in which the movable arm 16 is regulated by the regulating means 19 incorporated in the fixed arm 15. Even so, the distance is set such that the second holder 21 attached to the movable arm 16 does not interfere with the inner surface of the housing 27. The housing 27 may be configured by a member separate from the first holder 20 or may be a part of the first holder 20.

  In the region between the second holder 21 formed by providing the housing 27 and the inner surface of the housing 27, the gap 40 is filled with the medium 40 having deformability. The deformable medium 40 is preferably a gel-like substance. Here, the “gel-like substance” means a substance having fluidity at room temperature, not only a liquid consisting of a single substance, but also a liquid consisting of a mixture, a suspension in which fine particles are dispersed in a liquid, etc. Including.

  The property of the gel-like substance used as the medium 10 may be a low-viscosity substance such as water, or a substance having a certain degree of viscosity such as fats and oils (synthetic oil, mineral oil, vegetable oil). Also good. Alternatively, it may be a semi-solid material such as agar. Moreover, the medium 10 prepared by appropriately dissolving a polymer substance in a solvent such as water may be used. With such a preparation medium, the medium 10 having a desired viscosity can be easily obtained.

  When a gel-like substance is employed as the medium 10, when a relatively fine foreign substance such as dust comes into contact with the medium 10, it is considered that the foreign substance is caught by the surface tension of the medium 10. If the amount of foreign matter that the medium 10 is entrained increases, it may be considered that the magnetic field from the magnet 23 toward the Hall element 22 is affected. Therefore, assuming such a case, an elastic material such as a silicone resin or an epoxy resin can be used as the medium 10 instead of the gel substance. Since such an elastic material is not in a liquid state at room temperature, there is no possibility that it will be caught even if a foreign object comes into contact with it. For this reason, even if the displacement detection device 100 is placed in a poor environment with a lot of dust or the like, the gap D between the Hall element 22 and the magnet 23 is always protected from the outside, so that accurate displacement detection is possible over a long period of time. It becomes.

  Filling the gap 40 with the medium 40 can be performed by, for example, an injection device such as a syringe. Note that the medium 40 may be filled not only in the gap D but also over the entire region between the second holder 21 and the inner surface of the housing 27.

  Furthermore, as a method of filling the gap D with an elastic material, for example, an elastic material that has been molded into the shape of the gap D in advance is used when the displacement detector 100 is assembled with the first holder 20 and the second holder 21. Examples thereof include a method of sandwiching them in between, a method in which a monomer of the elastic material is filled in the gap D by an injection device such as a syringe, and the monomer is polymerized with heat or light to synthesize an elastic material.

  If such a gel-like substance or elastic material is used as the medium 40, the gap D is blocked from the outside, and foreign matters such as dust that adversely affects displacement detection are prevented from entering the gap D. For this reason, there is no possibility of disturbance of the magnetic field from the magnet 23 to the Hall element 22 causing a detection error in the scene of displacement detection. Further, even if the relative displacement between the fixed arm 15 and the movable arm 16, that is, the relative displacement between the Hall element 22 and the magnet 23 occurs, the medium 40 itself can flow and deform and follow the Hall element 22. There is no inconvenience such as inhibition of relative displacement with the magnet 23, and accurate displacement detection is possible over a long period of time.

  As described above, in the displacement detection device 100 of the present invention, the manufacturer and the user can select an appropriate medium 10 according to the design, use environment, and the like. In this respect, the displacement device 100 of the present invention. Can be said to have a wide range of applications.

(boots)
In order to protect the gap D between the hall element 22 and the magnet 23 from the outside, as shown in FIG. 4, from the housing 27 provided in the first holder 20 of the fixed arm 15 to the second holder 21 of the movable arm 16. It is also effective to provide a boot 50 made of a flexible material that covers the gap D. Providing such a boot 50 can also more reliably prevent foreign matter from entering the gap D, thereby improving the reliability of the displacement detection device 100 and enabling accurate displacement detection over a long period of time. Become.

  Moreover, since the boot 50 is made of a flexible material, it can be easily deformed with respect to the relative displacement between the Hall element 22 and the magnet 23. For this reason, the boot 50 does not become a great resistance to the displacement operation of the Hall element 22 and the magnet 23.

  In addition, if the boot 50 is provided with the protrusion 50a that is engaged with the edge of the housing 27, the boot 50 can be stably fixed, and the sealing performance of the gap D can be improved.

  As the flexible material constituting the boot 50, rubber, resin film, woven fabric, non-woven fabric, or the like can be used. Further, if a metal layer is formed on the boot 50 by vapor deposition, plating, laminating or the like, a magnetic shielding effect can be added, so that the influence of an external magnetic field received mainly by the Hall element 22 is reduced, and displacement detection accuracy is achieved. Can be prevented.

<Another embodiment>
(1) In the above embodiment, the housing 27 surrounding the second holder 21 is attached to the first holder 20. However, the housing is attached to the second holder 21 so as to surround the first holder 20. 2 The structure which fills the area | region between the holder 21 and the inner surface of the housing 27 with the medium which has a deformability may be sufficient.
(2) If the housing 27 attached to the first holder 20 or the second holder 21 is made of a magnetic shielding material such as metal, there is an effect of reducing the influence of an external magnetic field mainly received by the Hall element 22, and more accurate. Displacement can be detected.
(3) In the above embodiment, the displacement detection is performed using the torsional displacement by the torsion bar 17, but other displaceable members can also be used. For example, a spring that is compressed in proportion to the load may be provided between the fixed arm 15 and the movable arm 16, and the displacement may be detected using the compression displacement of the spring.
(4) The displacement detected by the hall element 22 and the magnet 23 is transmitted as an electric signal to a calculation means such as a computer (not shown), and the seat load is obtained by a displacement-load conversion program or the like stored in the calculation means. be able to.

  The displacement detection device of the present invention can be applied not only to detection of a seat load in a vehicle seat such as an automobile, but also to detection of a stepping amount of an accelerator pedal, detection of an open / close state of a sunroof device or a power window, and the like. . In addition, the displacement detection device of the present invention can be applied to various fields other than automobiles, for example, displacement detection sensors used for industrial machines.

The figure which shows the state which attached the displacement detection apparatus of this invention to the vehicle seat. The perspective view of the displacement detection apparatus of this invention (A) Front view and (b) SS ′ sectional view of the displacement detection device of the present invention The top view which shows the displacement detection apparatus which provided the boot consisting of the flexible material which covers a clearance gap

Explanation of symbols

DESCRIPTION OF SYMBOLS 15 Fixed arm 16 Movable arm 22 Hall element 23 Magnet 40 Medium 50 Boot 100 Displacement detection apparatus D Gap

Claims (5)

  In order to detect a relative displacement between the first member and the second member, a displacement detection device having a Hall element in the first member and a magnet in the second member, wherein the Hall element, the magnet, A displacement detecting device in which a gap between the two is filled with a medium having deformability.   The displacement detection device according to claim 1, wherein the medium is a gel substance.   The displacement detection device according to claim 1, wherein the medium includes a rust inhibitor.   The displacement detection device according to any one of claims 1 to 3, wherein a boot made of a flexible material covering the gap is provided from the first member to the second member.   In order to detect relative displacement between the fixed arm attached to the vehicle floor side and the movable arm attached to the seat side, the fixed arm includes one of a hall element or a magnet, and the movable arm includes the hall element or A displacement detection device for an automobile comprising the other of the magnets, wherein the gap between the Hall element and the magnet is filled with a medium having deformability.

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