JP2008080998A - Seating detection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seating detection device which reduces effects of temperature on connection characteristics of a pressure sensitive switch and obtains stable detection accuracy. <P>SOLUTION: At least either one of a pair of upper and lower film sheets 21, 21 is bent and formed, and a bent part 35 in which the film sheets 21, 22 vertically contact each other is provided. The bent part 35 is arranged so as to surround electrodes 51, 52. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a seating detection device that detects seating of an occupant on a seat.

  Conventionally, as a seating detection device, as shown in FIG. 11, a space 231 is provided between a pair of film sheets 221 and 222 arranged one above the other, and an electrode 251 is provided on the surface of each film sheet 221 and 222. What is provided with the pressure-sensitive switch 250 comprised by arrange | positioning so that 252 may be opposed is known. In such a seating detection device, the film sheets 221 and 222 are bent by the load when the occupant is seated, and the two electrodes 251 and 252 contact each other. Then, an electrical determination device determines that the pressure sensitive switch 250 is in a conductive state, and seating is detected.

  In such a pressure-sensitive switch 250 configuration, when a load is not applied, a spacer 225 is disposed so as to surround the space 231 in the horizontal direction in order to secure the pair of film sheets 221 and 222 at a predetermined interval. Yes. The spacer 225 is bonded and fixed to the pair of film sheets 221 and 222 by the adhesive member 228. The spacer 225 and the adhesive member 228 constitute a fixing portion that is bonded and fixed to the film sheets 221 and 222.

(For example, see Patent Document 1).
Japanese Patent No. 2990961

  However, in the configuration of the pressure-sensitive switch 250 of the conventional seating detection device described above, the film sheets 221 and 222 are fixed by the adhesive member 228 in the portion around the space 231. The physical properties of the pressure-sensitive adhesive member 228 are set so as to obtain good adhesiveness, but the material hardness changes greatly due to temperature changes as compared with the film sheets 221 and 222. In particular, the hardness of the adhesive member 228 greatly increases at low temperatures, and the film sheets 221 and 222 whose periphery is supported by the adhesive member 228 are difficult to bend. On the contrary, it becomes easy to bend at a high temperature, and the pressure-sensitive switch 250 becomes conductive even with a slight load. The detection accuracy is greatly affected by the temperature, and the detection accuracy is not stable.

  The present invention has a problem to be solved by proposing a seating detection device that can reduce the influence of temperature on the detection accuracy of the pressure-sensitive switch in the above-described prior art and obtain stable detection accuracy.

  The technical means taken in the present invention in order to solve the above-mentioned problem is that a film sheet arranged in a pair of upper and lower sides in a seat on which an occupant sits is connected by deformation of the film sheet due to a load applied on the sheet. In a seating detection device comprising: a pressure-sensitive switch comprising an electrode provided in close contact with the film sheet; and a determination circuit for detecting connection of the pressure-sensitive switch, at least one of the pair of upper and lower film sheets One of the film sheets is bent and formed, and a bent portion where the film sheets are in contact with each other is provided, and the bent portion is disposed so as to surround the electrode.

  According to a second technical means of the present invention as set forth in claim 2, a fixing portion for fixing the pair of film sheets is provided, and the bent portion is provided between the fixing portion and the electrode. It is characterized by being arranged in.

  The third technical means taken in the present invention as claimed in claim 3 is characterized in that the bent portion is provided with a vent hole that communicates between the electrode side and the opposite side across the bent portion. Yes.

  Furthermore, the 4th technical means taken by this invention as described in Claim 4 forms the said bending part only in one side of the said upper-lower pair of said film sheet, and the said other film sheet without the said bending part The first electrode and the second electrode are provided, and the one electrode sheet is provided with a third electrode that contacts the first electrode and the second electrode and connects the first electrode and the second electrode. The pressure-sensitive switch configured as described above is provided.

  According to the first aspect of the present invention, at least one of the pair of upper and lower film sheets is bent and formed, the bent portions are provided so that the film sheets are in contact with each other vertically, and the bent portions are disposed so as to surround the electrodes. Therefore, it is possible to realize a seating detection device having a stable detection accuracy without being affected by a temperature change by the bent portion formed by the film sheet.

  Further, according to the invention described in claim 2, since the fixing portion for fixing the pair of film sheets is provided and the bent portion is disposed between the fixing portion and the electrode, the influence of the temperature change of the fixing portion is affected. Without having it, it can have the flex characteristic of the film sheet. As a result, the detection accuracy of the pressure-sensitive switch is hardly affected by temperature, and a seating detection device having stable detection accuracy can be realized.

  Further, according to the invention described in claim 3, since the bent portion is provided with a vent hole that communicates between the electrode side and the bent portion so as to communicate the opposite side, for example, air in the space in which the bent portion is surrounded and the electrode is disposed Since it can be easily moved in and out through the air holes, a change in the air pressure in the space does not affect the detection accuracy of the pressure sensitive switch, and a seating detection device with more stable detection accuracy can be realized.

  Furthermore, according to the invention described in claim 4, the bent portion is formed only on one of the pair of upper and lower film sheets, the first electrode and the second electrode are provided on the other film sheet without the bent portion, Since the film sheet is provided with a pressure-sensitive switch configured by providing a third electrode that contacts the first electrode and the second electrode and connecting the first electrode and the second electrode, the electrode and wiring are inexpensive by a pattern printing method or the like. It can be provided on the film sheet.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings.

(Embodiment)
FIG. 1 is a plan view showing a seating detection device 2 of the present embodiment. The seating detection device 2 includes a pressure sensing unit 5 and a detection unit 6 that determines whether a passenger is seated on the seat 1 (FIG. 9) based on an electrical signal from the pressure sensing unit 5.

 As shown in FIGS. 9 and 10, the pressure sensing unit 5 of the seating detection device 2 is disposed in a seat cushion 10 on which the weight of the occupant acts when the occupant sits on the vehicle seat 1. As shown in detail in the sectional view of the seat cushion 10 in FIG. 10, the pressure-sensitive portion 5 having a planar shape is disposed between the seat skin 13 and the cushion pad 14 made of an elastic material such as foamed resin. ing.

 Further, as shown in FIG. 1, the pressure sensing unit 5 of the seating detection device 2 includes a number of pressure sensitive switches 50 configured to be connected. FIG. 6 is an electric circuit diagram of the seating detection device 2, and the pressure sensitive switches 50 are electrically connected in parallel by wires 57 and 58 in the pressure sensitive unit 5. The power supply voltage Vcc is input to the detection unit 6 when at least one of the pressure sensitive switches 50 is connected. Then, it is determined by the detection unit 6 that an occupant is seated.

 2 and 3 are enlarged views of one pressure-sensitive switch 50 and are shown in a plan view and a central sectional view. The pressure sensitive switch 50 is shown in a state when no occupant is seated on the seat cushion 10.

 The pressure sensitive switch 50 includes an upper film sheet 21 and a lower film sheet 22 that are arranged in a pair of upper and lower sides. A spacer 25 having a predetermined thickness is arranged between the upper film sheet 21 and the lower film sheet 22. Adhesive members 28 are attached to the upper and lower surfaces of the spacer 25, and the upper and lower film sheets 21 and 22 and the spacer 25 are bonded and fixed. The spacer 25 and the adhesive member 28 constitute a fixing portion that fixes the pair of upper and lower film sheets 21 and 22.

 Further, between the upper and lower film sheets 21, 22, there is a space 31 provided so that the spacer 25 is not partially disposed and the periphery is surrounded by the spacer 25 and the adhesive member 28. Located in the space 31, an upper electrode 51 is provided on the upper film sheet 21 and a lower electrode 52 is provided in close contact with the lower film sheet 22 by a method such as pattern printing.

 As further shown in FIG. 3, the upper film sheet 21 includes a bent portion 35 formed by bending the upper film sheet 21 into a V-shaped groove shape. The bent portion 35 extends to surround the space 31 and has an annular shape. The lower end portion 35 a of the bent portion 35 has a shape that comes into contact with the upper surface of the lower film sheet 22 in a state where no load is applied to the pressure sensitive switch 50. When the bent portion 35 is in contact with the upper surface of the lower film sheet 22, a predetermined interval can be maintained between the upper film sheet 21 and the lower film sheet 22 without interposing an adhesive member or the like.

 FIG. 4 shows the pressure-sensitive switch 50 when an occupant is seated on the seat cushion 10, and is a cross-sectional view at the center of the pressure-sensitive switch 50 as in FIG. 3. The seat skin 13 and the cushion pad 14 are compressed downward by the load of the occupant, and the upper and lower film sheets 21 and 22 of the pressure-sensitive switch 50 bend in the direction close to each other. Then, the upper electrode 51 and the lower electrode 52 come into contact with each other and are electrically connected.

 When a load is applied to the pressure-sensitive switch 50, the bent portion 35, which is a V-shaped groove, opens the V-shaped groove because the lower end portion 35a is in contact with the lower film sheet 22. Transforms into And the upper film sheet 21 is easy to bend below the other part in the inner part of the annular bent part 35, and the detection accuracy of the pressure sensitive switch 50 is improved.

  On the other hand, the adhesive members 28 above and below the spacer 25 are hardly compressed when the space 31 is deformed, and have a configuration that hardly affects the detection accuracy of the pressure-sensitive switch 50. Therefore, even if the hardness of the adhesive member 28 changes greatly with temperature, the connection characteristics of the pressure sensitive switch 50 are not affected.

  In order to minimize the change due to the temperature of the pressure-sensitive switch 50, the material of the upper and lower film sheets 21 and 22 can be realized by applying a material whose hardness is not changed as much as possible. Since the bent portion 35 is bent by a film sheet and is formed of the same member as the film sheet, it is possible to reduce the influence of temperature change on the bending characteristics of the film sheet 21 to which the electrode 51 is in close contact.

  On the other hand, the material of the adhesive member 28 can be selected so as to obtain the best adhesion between the spacer 25 and the upper and lower film sheets 21 and 22.

 3 and 4, the upper film sheet 21 is provided with a bent portion 35. As is apparent from the above description, the upper and lower film sheets 21, Any structure may be used as long as 22 are brought into contact with each other and bent easily. Therefore, a structure in which the bent portion 35 is provided on one or both of the upper and lower film sheets 21 and 22 may be adopted.

 FIG. 5 shows a VV cross section in FIG. The lower end portion 35a of the bent portion 35 is cut out at a portion that contacts the surface of the lower film sheet 22 so that air in the space 31 located on the electrode 51 side of the bent portion 35 can easily sandwich the bent portion 35 between the electrodes. A vent hole 32 is formed so as to allow access to the outside located on the opposite side of 51. The vent hole 32 minimizes the influence of changes in the air pressure in the space 31 when the pressure sensitive switch 50 is deformed by a load.

 Next, the operation of the seating detection device 2 configured as described above will be described. When a predetermined load or more is applied to the seat cushion 10, the power supply voltage Vcc is input to the detection unit 6 as a signal by connecting at least one of the plurality of pressure sensitive switches 50. The detection unit 6 includes a determination circuit 61 having a threshold set lower than the power supply voltage Vcc, and determines that an occupant is seated on the seat cushion 10 based on an input signal.

 Next, a pressure sensitive switch 150 according to a second embodiment of the present invention will be described with reference to FIGS.

 The first electrode 151 and the second electrode 152 are arranged in a space 31 of the pressure-sensitive switch 150 so as to face each other with a predetermined interval on the surface of the lower film sheet 22 where the bent portion 35 is not provided. is doing. A third electrode 153 is provided on the surface of the upper film sheet 21 including the bent portion 135.

 The first electrode 151 and the second electrode 152 are connected to the first electrode 151 and the second electrode 152 of the other pressure-sensitive switch 150 by wirings 157 and 158, respectively. On the other hand, the third electrode 153 has no wiring.

 When a load is applied to the pressure sensitive switch 150, the third electrode 153 contacts both the first electrode 151 and the second electrode 152, and the first electrode 151 and the second electrode 152 are conducted. The pressure sensitive switch 150 configured as described above has an advantage that it is not necessary to provide a wiring for an electrode on the surface of the bent portion 35 and the manufacturing is facilitated.

It is a top view of the seating detection apparatus concerning an embodiment. It is a top view of the pressure sensitive switch of the seating detection apparatus which concerns on embodiment. It is sectional drawing in III-III of FIG. 3, and the state where the load is not acting on a pressure sensitive switch is shown. It is sectional drawing in III-III of FIG. 3, and the state which the load is acting on the pressure sensitive switch is shown. It is VV sectional drawing of FIG. It is an electric circuit diagram of the seating detection device according to the embodiment. It is a top view of the 2nd example of a pressure sensitive switch of a seating detection device concerning an embodiment. It is sectional drawing in VIII-VIII of FIG. It is a perspective view of the sheet | seat provided with the seating detection apparatus which concerns on embodiment. It is sectional drawing in XX of FIG. It is sectional drawing of the pressure-sensitive switch in embodiment of the conventional seating detection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sheet 2 ... Seating detection apparatus 21 ... Upper film sheet (film sheet)
22 ... Lower film sheet (film sheet)
25 ... Spacer 28 ... Adhesive member 31 ... Space 32 ... Vent hole 35 ... Bent part 50 ... Pressure sensitive switch 51 ... Upper electrode (electrode)
52 ... Lower electrode (electrode)
61 ... Determination circuit 151 ... First electrode 152 ... Second electrode 153 ... Third electrode

Claims (4)

A film sheet arranged in a pair of upper and lower sides in a seat on which an occupant sits;
A pressure sensitive switch comprising an electrode provided in close contact with the film sheet so as to be connected by deformation of the film sheet due to a load applied on the sheet;
In a seating detection device comprising a determination circuit for detecting connection of the pressure sensitive switch,
A seating detection device in which at least one of the pair of upper and lower film sheets is bent and formed, a bent portion is provided in which the film sheets are in contact with each other vertically, and the bent portion is disposed so as to surround the electrode.  The seating detection device according to claim 1, wherein a fixing portion that fixes the pair of film sheets is provided, and the bent portion is disposed between the fixing portion and the electrode.   The seating detection device according to claim 1, wherein the bent portion includes a vent hole that communicates between the electrode side and the opposite side across the bent portion. The bent portion is formed only on one of the pair of upper and lower film sheets, the first electrode and the second electrode are provided on the other film sheet without the bent portion, and the first electrode is provided on the one film sheet. 4. The seating detection device according to claim 1, further comprising the pressure-sensitive switch configured to provide a third electrode that contacts the second electrode and connects the first electrode and the second electrode. 5.

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