JP4711142B2 - Matte sensor and manufacturing method thereof - Google Patents

Description

  The present invention relates to a mat sensor and a method for manufacturing the same, and more particularly, is used for a stepping mat for an automatic door, a seat for an automobile, a mattress for a bed, and the like to detect whether or not a person or an object is placed on the mat. The present invention relates to a mat sensor and a manufacturing method thereof.

  A mat sensor with a load / pressure detection cord switch wired to the mat is installed on an automatic door tread mat, a car seat, bed mattress, indoor floor, etc. It is used as a planar pressure sensor (mat switch) for detecting whether or not it is placed on the surface, or detecting the entry / exit / intrusion of a person or object.

A conventional mat sensor includes a plurality of linear load detection sensors, each having a pressure-sensitive sensor body incorporated in a rectangular tubular package, arranged in parallel on a vehicle seat surface or the like (see Patent Document 1). A mat formed by laminating a cushion material of a layer, in which a linear switch is meandered and fixed on a laminating surface between the cushion materials of two layers (see Patent Document 2), and a wire is placed on a cushion portion such as a seat seat There is known one that is bonded and fixed using a flexible sheet having an adhesive layer on the back surface so as to cover the load sensor (see Patent Document 3). In these mat sensors, a method is described in which a linear sensor (load detection sensor, linear switch, load sensor) functioning as a code switch is installed and fixed in a groove for positioning the cushion material or sponge material. .
JP 2001-167660 A JP 2005-235664 A JP 2003-57129 A

However, in the mat sensor in which the groove for positioning the linear sensor (code switch) is provided in the cushion material or the sponge material described above, the positional deviation of the groove from the arrangement position of the linear sensor can be prevented to some extent by providing the groove. Since the width of the groove is the same as or larger than the width of the linear sensor, the linear sensor is easily detached from the groove, and until the adhesive that fixes the linear sensor in the groove is fixed. It had to be temporarily fixed with tape etc., and it took time and effort.
Therefore, it is conceivable to fix the linear sensor with a tape as in Patent Document 3, or to fix it with an instantaneous adhesive. However, with a tape or an instantaneous adhesive, use of a mat sensor in a high temperature environment or a long-term use is possible. There is a problem with reliability.
Also, in order to reduce the cost and reduce the insensitive part of the sensor, when wiring a single linear sensor (code switch) by bending it into the mat surface, the linear sensor is bent. Stress is generated in the bent portion, and the linear sensor comes out immediately from the curved groove portion. For this reason, it takes time for the wiring of the linear sensor, and the number of temporarily fixed portions with tape or the like increases, and the wiring work takes time. Also, expensive and strong adhesives had to be used.

  An object of the present invention is to solve the above-described problems and provide a mat sensor and a method of manufacturing the mat sensor, in which a cord switch can be easily wired and installed.

In order to solve the above problems, the present invention is configured as follows.
A first aspect of the present invention is a mat sensor in which a cord switch that switches when a load is applied is disposed, and is elastically deformed by the load between a flexible upper surface sheet and a lower surface sheet. A foamed resin layer is provided, and at least the foamed resin layer is formed with a storage groove for storing the cord switch, and the storage groove of the storage groove when no load is applied to the foamed resin layer over the entire length or a part of the storage groove. At least a part of the width is smaller than the width of the cord switch when there is no load, and the cord switch is housed in the housing groove so that the cord switch is elastically deformed by the housing groove of the foamed resin layer. constructed to hold, the cord switch is switched react displacement varying change point at which collapse displacement load of the foamed resin layer is rapidly changed Less than a and the mat sensor fracture displacement being greater than the change point displacement of the foamed resin layer in which the cord switch is broken.

  According to a second aspect of the present invention, in the mat sensor according to the first aspect, the width of at least a part of the storage groove when no load is applied is 0.7 to 0.98 of the width of the cord switch when no load is applied. It is characterized by being double.

  According to a third aspect of the present invention, in the mat sensor according to the first aspect or the second aspect, the depth of the storage groove when no load is greater than the height of the cord switch when no load is applied. And

  According to a fourth aspect of the present invention, in the mat sensor according to any one of the first to third aspects, the storage groove has a curved groove portion, and the cord switch is bent into the curved groove portion. It is characterized by being arranged.

According to a fifth aspect of the present invention, in the mat sensor according to any one of the first to fourth aspects, the expansion ratio of the foamed resin layer is 5 to 100 times.

According to a sixth aspect of the present invention, in the mat sensor according to any one of the first to fifth aspects, the foamed resin layer includes a high foamed resin layer and a low foamed resin layer, and the code switch is switched. Until the reaction displacement, the high foam resin layer is mainly crushed and deformed, and the low foam resin layer mainly prevents the deformation of the cord switch as it approaches the fracture displacement that the cord switch breaks. .

According to a seventh aspect of the present invention, in the mat sensor according to any one of the first to sixth aspects, a solid layer is used instead of the low foamed resin layer in the foamed resin layer.

According to an eighth aspect of the present invention, in the mat sensor according to any one of the first to seventh aspects, the cord switch includes an insulator having a hollow portion and an inner wall surface portion of the insulator that defines the hollow portion. A plurality of conductive members that are respectively held and spirally wired along the longitudinal direction of the hollow portion while being spaced apart from each other.

According to a ninth aspect of the present invention, the cord is provided in a housing groove for housing a cord switch formed on the foamed resin layer and a step of joining the planar foamed resin layer on the flexible lower surface sheet. A step of housing the switch and installing the cord switch in a state where the cord switch is held in a portion of the housing groove having a width smaller than the width of the cord switch; and a flexible top sheet covering the foamed resin layer. possess and bonding the lower sheet, wherein the cord switch is smaller than the change point displacement collapse displacement load of the foamed resin layer and the reaction displacement of switching abruptly changes, and the code switch to break fracture The mat sensor manufacturing method is characterized in that the displacement is larger than the change point displacement of the foamed resin layer .

  According to the present invention, since the cord switch is held by elastic deformation of the housing groove portion of the foamed resin layer, the cord switch can be wired and installed easily and quickly without temporarily fixing the tape or the like.

Embodiments of a mat sensor and a manufacturing method thereof according to the present invention will be described below with reference to the drawings.
FIG. 1 shows a mat sensor 1 of the present embodiment, FIG. 1 (a) is a plan view of the mat sensor 1, and FIG. 1 (b) is an enlarged cross-sectional view along BB in FIG. 1 (a). A foamed resin layer 4 that is elastically deformed by a load is provided between the upper surface sheet 2 and the lower surface sheet 3 having flexibility. The foamed resin layer 4 is formed with a storage groove (slit-like opening, through hole) 5 for storing a cord switch 6 that switches when a load is applied. The width of the storage groove 5 when the foamed resin layer 4 is not loaded is smaller than the width (diameter) of the cord switch 6 when no load is applied before the cord switch 6 is stored in the storage groove 5. When the cord switch 6 is housed, the cord switch 6 is held and sandwiched by elastic deformation of the housing groove 5 portion of the foamed resin layer 4.

  The storage groove 5 is formed by meandering the foamed resin layer 4, and a single continuous cord switch 6 is stored in the storage groove 5 as shown in FIG. The load and pressure can be detected. Note that a plurality of linear storage grooves may be formed in the foamed resin layer 4, and the cord switch 6 may be stored in each storage groove.

  The upper surface sheet 2 and the lower surface sheet 3 are flat sheets, and the materials thereof are harder than the foamed resin layer 4, but are flexible and elastic rubber materials such as chloroprene rubber, ethylene propylene rubber, natural Examples thereof include rubber and nitrile rubber. The surface of the upper surface sheet 2 and the lower surface sheet 3 may be embossed or the like for design or for preventing slipping.

  The foamed resin layer 4 is a flat layer interposed between the upper sheet 2 and the lower sheet 3. The material of the foamed resin layer 4 is urethane, polyethylene, chloroprene rubber, ethylene propylene rubber, or the like. The hardness of the foamed resin layer 4 is determined by the foaming ratio and the material, but the foaming ratio is 5 to 100 times from the viewpoint of holding the cord switch 6 by the storage groove 5 and the operation / sensitivity characteristics of the cord switch 6. It is preferable to use one having a degree.

  Since the width of the storage groove 5 is smaller than the width of the cord switch 6, when the cord switch 6 is fitted in the storage groove 5 and wired, the cord is caused by elastic deformation / compression deformation of the foamed resin layer 4 in the storage groove 5 portion. The switch 6 is held and held. For this reason, the cord switch 6 does not easily come out or rise out of the storage groove 5, and it is not necessary to temporarily fix (temporarily hold) the cord switch 6 with tape or the like, and the wiring and installation work of the cord switch 6 becomes easy. In particular, when the cord switch 6 is bent and bent in a meandering manner in the mat surface, stress is generated at the bent portion of the cord switch 6 and the cord switch 6 is easily pulled out from the storage groove 5. However, since the cord switch 6 is held by making the groove width of the storage groove 5 smaller than the width of the cord switch 6, the cord switch 6 can be easily wired and installed.

  The width of the storage groove 5 when there is no load is the width (diameter) of the cord switch 6 when there is no load so that the stored cord switch 6 can be held well and the operation and sensitivity of the cord switch 6 are not affected. The ratio is preferably 0.7 to 0.98 times. In addition, the depth of the storage groove 5 when there is no load is preferably larger than the height of the cord switch 6 when there is no load (the dimension of the storage groove 5 in the depth direction). The cord switch 6 can be securely held, and the cord switch 6 does not protrude from the surface of the foamed resin layer 4 so that the mat surface does not become uneven.

  As shown in FIG. 2, the cord switch 6 has four tubular insulators 7 each having a hollow portion 11 and four inner walls (inner circumferential surfaces) held by the inner wall surface (inner peripheral surface) of the insulator 7 that defines the hollow portion 11. The conductive member 8. The four conductive members 8 are spirally wired at substantially the same pitch along the longitudinal direction of the hollow portion 11 while being spaced apart from each other, and the four conductive members 8 are opposed to each other in the cross section of the insulator 7. It is arranged and maintained. The insulator 7 is made of a restoring rubber or a restoring plastic, and is deformed by being crushed when a load (pressing pressure) is applied. When the load (pressing pressure) disappears, the insulator 7 is restored to the original circular cross-sectional shape. The conductive member 8 is obtained by covering a metal wire (stranded wire) 9 with a conductive resin 10 such as conductive rubber. When the insulator 7 is crushed and deformed and the conductive members 8 and 8 come into contact with each other, the resistance value between the conductive members 8 changes, and the change in the resistance value causes the ON / OFF switch operation to apply a load (pressing pressure). Detect. The thickness of the insulator 7 between the conductive members 8 and 8 adjacent to the inner peripheral surface of the tubular insulator 7 is partly thin, and the insulator 7 is easily crushed and easily deformed. Further, the conductive member 8 of the cord switch 6 is connected to the external wiring 12 via the connector 13 as shown in FIG.

Next, the operation of the mat sensor 1 of the present embodiment will be described.
FIG. 3 shows a state in which a person or a moving body is placed on the mat sensor 1 and a load due to pressing pressure is applied. When a load is applied to the top sheet 2 of the mat sensor 1, the foamed resin layer 4 and the cord switch 6 in the portion where the load is applied are pressed and deformed in the thickness direction. Due to this deformation, the conductive members 8 and 8 of the cord switch 6 are brought into contact with each other to be turned on, and an ON signal current flows through the external wiring 12 to detect that a person or a moving body is placed on the mat sensor 1.

The reaction displacement at which the code switch 6 switches (the minimum displacement at which the conductive members 8 of the code switch 6 are in contact with each other) is made smaller than the change point displacement at which the crushing displacement load of the foamed resin layer 4 changes suddenly. It is preferable that the breaking displacement at which the cord breaks (the displacement at which the cord switch 6 is deformed and broken) is larger than the change point displacement of the foamed resin layer 4 (see FIGS. 11 and 13).
When the crushing deformation of the foamed resin layer 4 is small, the air layer (bubbles) inside the foamed resin layer 4 is deformed, so that it deforms with a small load. The load increases (see FIG. 13). When the reaction displacement of the cord switch 6 is smaller than the change point displacement of the foamed resin layer 4 where the load changes rapidly, the crushing load of the foamed resin layer 4 is small, so that the reactivity (reaction load) of the cord switch 6 is inhibited. Therefore, the mat sensor 1 having a low load and high reactivity is obtained.
If the breaking displacement of the cord switch 6 is larger than the change point displacement of the foamed resin layer 4, the load required to reach the breaking displacement of the cord switch 6 increases rapidly (the crushing load of the foamed resin layer 4 changes to the changing point). As a result, the cord switch 6 is not easily broken, and the mat sensor 1 is excellent in durability and load resistance.

Next, a method for manufacturing the mat sensor 1 will be described with reference to FIG.
First, a pre-formed top sheet 2, bottom sheet 3, foamed resin layer 4 and cord switch 6 are prepared, and the foamed resin layer 4 is bonded onto the bottom sheet 3 with an adhesive, and then stored in the foamed resin layer 4. 5 is formed (FIG. 4A).
Next, the cord switch 6 is wired along the storage groove 5 of the foamed resin layer 4 (FIG. 4B). At this time, as described above, since the width of the storage groove 5 of the foamed resin layer 4 is smaller than the width of the cord switch 6, it is easy to bend the cord switch 6 and perform bending wiring. Further, even when the lower surface sheet 3 and the cord switch 6 are bonded and fixed with an adhesive, temporary fixing or the like using a tape or an instantaneous adhesive is not required until the adhesive is cured.
Finally, the foamed resin layer 4 is covered with the top sheet 2, and the top sheet 2 and the bottom sheet 3 are bonded together using an adhesive. The upper surface sheet 2 and the lower surface sheet 3 are in contact with each other at their outer edge portions, and are tightly integrated with an adhesive (FIG. 4C).

  In the above manufacturing method, after the foamed resin layer 4 was bonded to the lower surface sheet 3 with an adhesive, the storage groove 5 was formed in the foamed resin layer 4, but before the foamed resin layer 4 was bonded to the lower surface sheet 3, The storage groove 5 may be formed in the foamed resin layer 4 in advance. Alternatively, the foamed resin layer 4 may be first bonded to the upper surface sheet 2, the cord switch 6 may be wired in the storage groove 5, and then the lower surface sheet 3 may be bonded to the upper surface sheet 2.

  In the mat sensor 1 of the above embodiment shown in FIG. 1, the foamed resin layer 4 is a single layer, and the foamability of the foamed resin layer 4 is deformed with a small load until the displacement at which the cord switch 5 reacts. An appropriate foaming ratio and material foaming layer are selected so that the load increases rapidly before the cord switch 5 is displaced to break. In the foamed resin layer 40 shown in FIG. 5, such characteristics are realized by a two-layer structure of a high foamed resin layer 41 and a low foamed resin layer 42. In the foamed resin layer 40, the soft foamed resin layer 41 is mainly crushed and deformed until the reaction displacement at which the cord switch 6 switches, and the reactivity of the cord switch 6 under a low load is ensured. The cord switch 6 is mainly prevented from being deformed by the hard low-foamed resin layer 42 as it approaches the breaking displacement at which the cord switch 6 breaks, thereby preventing the cord switch 6 from being broken.

  Further, the low foamed resin layer 42 in the foamed resin layer 40 in FIG. 5 may be replaced with a solid layer. Further, as shown in FIG. 6 (a), a groove continuous to the lower side of the opening (storage groove) through which the foamed resin layer 4 passes is formed as a storage groove 51 formed in the lower surface sheet 3, and the groove portion of the lower surface sheet 3 is formed. You may make it function as a solid layer.

In addition, the storage groove 5 of the embodiment of FIG. 1 has a rectangular cross section with a constant width in the depth direction penetrating the foamed resin layer 4 over its entire length. For example, the groove width of only the curved storage groove 5 may be made smaller than the width of the cord switch 6.
Further, instead of the storage groove 5 having a constant width in the depth direction, it is sufficient if at least a part of the storage groove has a cross-sectional shape smaller than the width of the cord switch 6 when no load is applied. For example, as shown in FIG. 6B, the storage groove 52 having a tapered cross-sectional shape having a narrow opening on the insertion side of the cord switch 6 and a wide bottom sheet 3 side, or as shown in FIG. 6C. Alternatively, the storage groove 53 may have a cross-sectional shape such that the foamed resin layer 4 partially protrudes in the direction of closing the opening of the storage groove. Even in the storage grooves 52 and 53 having such a cross-sectional shape, the cord switch 6 to be stored can be held and clamped to prevent the cord switch 6 from coming out of the storage grooves 52 and 53.

In the cord switch 6 shown in FIG. 2, four conductive members 8 are spirally wired along the longitudinal direction of the hollow portion 11 while being spaced apart from each other on the inner wall surface portion of the insulator 7 having the hollow portion 11. Therefore, the load and pressure from all directions can be detected, and the flexibility is very excellent, and the wiring can be installed by bending to a diameter of about 20 mm without buckling. Further, since the conductive members 8 are not easily brought into contact with each other by bending, the switch function is exhibited even in the bent state. Further, the mat sensor 1 can be used on a floor or the like that is not flat. Furthermore, since the mat sensor 1 is configured by using the top sheet 2, the bottom sheet 3, the foamed resin layer 4, and the cord switch 6 having excellent flexibility, the mat sensor 1 can be bent or rolled. Easy handling, storage and storage. Furthermore, the diameter of the cord switch 6 can be reduced, and the mat sensor 1 can be reduced in thickness and weight.
In addition, by connecting four electrodes as the conductive member 8 of the cord switch 6 in series via resistors, when the electrodes are in a non-contact OFF state, the electrodes show a certain resistance value, and for some reason When the electrode switch is broken and the cord switch 6 is damaged, the resistance value is changed. Therefore, by detecting this, the breakage of the code switch 6 can be detected.
Moreover, it is preferable that the surface of the cord switch 6 has a waterproof structure. The upper surface sheet 2 and the lower surface sheet 3 are in contact with each other at the outer edge and are liquid-tightly bonded with an adhesive. However, even if the upper surface sheet 2 and the lower surface sheet 3 of the mat sensor 1 are cracked and water enters, the cord switch Since the surface of 6 has a waterproof structure, the switch function of the cord switch 6 is maintained, so that the sensor function of the mat sensor 1 can be maintained.

In the cord switch 6 shown in FIG. 2, four conductive members 8 are spirally wired on the inner wall surface of the insulator 7 having the hollow portion 11, but spirally along the inner wall surface of the insulator 7. It is sufficient to provide two or more conductive members 8.
Further, as another embodiment of the cord switch, as shown in FIG. 7A, two conductive members 22 (metal wires) having a rectangular cross section are formed on the inner wall surfaces of the upper and lower side walls of the rectangular tubular insulator 21. Alternatively, a cord switch 61 may be used in which a conductive resin 24 is coated in a straight line along the longitudinal direction of the insulator 21 with a gap therebetween. Further, as shown in FIG. 7B, a piezoelectric rubber 28 is provided between the upper electrode 26 and the lower electrode 27, and the outer periphery thereof is covered with an insulating resin 29. 7 (c), a code switch having a coaxial structure in which a piezo element (piezoelectric resin) 31 is provided between the inner electrode 30 and the outer electrode 32 on the outer periphery thereof, and the outer periphery of the piezo element 31 is covered with an insulating resin 33. 63 may be used.

Next, examples of the present invention will be described.
FIG. 8 shows a plan view of the mat sensor 81 of the present embodiment. The size of the mat sensor 81 is 700 mm × 500 mm. The top sheet 82 and the bottom sheet (not shown) were made of 700 mm × 500 mm rectangles and 1 mm thick chloroprene rubber. Chloroprene rubber is elastic and flame retardant. The surface of the top sheet 82 was embossed as an anti-slip process. The upper surface sheet 82 was bonded to the lower surface sheet with an adhesive at the outer edge portion 82a.

A foamed resin layer 84 shown in FIG. 9 is provided in the waterproof mat sensor 81 in which the upper sheet 82 and the lower sheet are bonded together. The foamed resin layer 84 had dimensions of 660 mm × 460 mm × 5 mm, and the material used was UEM55 (foamed urethane, density 55 ± 3 kg / m ³ , foaming ratio of about 20 times) manufactured by INOAC Corporation. The foamed resin layer 84 is formed over the entire area of the mat sensor 82 along the outer periphery of the mat sensor 82 while meandering the storage groove 85 so as to eliminate the sensor insensitive area and blind spot. Specifically, as illustrated, in the meandering portion of the storage groove 85, the interval between the linear storage grooves 85 is set to 70 mm, and the curvature radius of the curved storage groove 85 is set to 35 mm.

As shown in FIG. 10, the cord switch 86 housed in the housing groove 85 has the same structure as the cord switch 6 shown in FIG. 2 and has an outer diameter of 4.6 mm. The circular tubular insulator 87 is made of insulating rubber. The conductive member 88 has an outer diameter of 0.85 mm, and the metal wire 89 is covered with a conductive rubber 90. The interval between the conductive members 88 was 0.74 mm, and the thickness of the thin portion of the insulator 87 between the conductive members 88 was 0.7 mm.
The thickness of the foamed resin layer 84 is 5 mm, which is larger than the outer diameter 4.6 mm of the cord switch 86 accommodated in the accommodation groove 85, so that the cord switch 86 does not rise from the surface of the foamed resin layer 84 and become uneven. I made it. Further, the width of the storage groove 85 is 4.1 mm, which is smaller than the diameter of the cord switch 86 so that it can be temporarily fixed by being fitted into the cord switch 86.

  FIG. 10 is an explanatory diagram for explaining a method of measuring the relationship between the thickness of the cord switch 86 and the resistance when the cord switch 86 is crushed and deformed by applying a load. Using an indenter jig 101 having a size of 10 mm × 25 mm on the lower surface, a load was applied to the cord switch 86 in the radial direction, and the relationship between the thickness of the cord switch 86 that deformed by crushing and the resistance was measured.

  FIG. 11 shows the relationship between the thickness (mm) and the resistance (Ω) of the cord switch 86 by the above measurement. From the measurement results, the range where the thickness of the cord switch 86 is 3.1 mm to 3.6 mm is a reaction displacement region (1 to 1.5 mm) in which the cord switch 86 reacts, and the thickness of 0.9 mm is the cord switch 86. The breaking displacement to be broken (3.7 mm).

  FIG. 12 is an explanatory view illustrating a method for measuring the relationship between the thickness of the foamed resin layer 84 and the load when the foamed resin layer 84 is deformed by applying a load. Similar to FIG. 10, using an indenter jig 101 having a bottom surface size of 10 mm × 25 mm, a load was applied to the foamed resin layer 84 in the thickness direction, and the relationship between the thickness of the foamed resin layer 84 to be compressively deformed and the load was measured. .

  FIG. 13 shows the relationship between the thickness (mm) and the load (N) of the foamed resin layer 84 by the above measurement. As shown in FIG. 13, the foamed resin layer 84 was deformed with a low load up to a thickness of 1.8 mm, but the load required to compressively deform to 1.8 mm or more increased rapidly. Accordingly, the change point displacement of the foamed resin layer 84 is when the thickness becomes 1.8 mm, and the change point displacement (3.2 mm) is a low load region, and when the thickness exceeds 1.8 mm, the change is high. It becomes a load area.

From the results of FIGS. 11 and 13, thickness of 1.8mm and name Ru change point displacement of the foamed resin layer 84 (3.2 mm), the thickness of the cord switch 86 is 3.1mm~3.6mm It is sufficiently larger than the reaction displacement area (1 to 1.5 mm) of the cord switch 86 in the range and sufficiently smaller than the breaking displacement (3.7 mm) of the cord switch 86 in which the thickness of the cord switch 86 is 0.9 mm. . For this reason, it has been confirmed that the cord switch 86 is extremely difficult to break, and can exhibit a characteristic with good reactivity at a low load.

The mat | matte sensor of one Embodiment of this invention is shown, Fig.1 (a) is a top view, FIG.1 (b) is BB expanded sectional drawing of Fig.1 (a). It is a figure which shows the cord switch of FIG. It is sectional drawing which shows the state in which the load was added to the mat | matte sensor of FIG. It is process drawing which shows the manufacturing method of the mat sensor of FIG. It is sectional drawing for demonstrating the foamed resin layer in the mat sensor of other embodiment of this invention. It is sectional drawing which shows the foamed resin layer in the mat | matte sensor of other embodiment of this invention. It is sectional drawing which shows other embodiment of the cord switch used for this invention. It is a top view of the mat | matte sensor of one Example of this invention. It is a top view of the foaming resin layer of the mat | matte sensor of FIG. It is explanatory drawing explaining the method to measure the relationship between the thickness of a cord switch, and resistance when applying a load to the cord switch used for the mat | matte sensor of FIG. 8, and making it deform | transform. It is a figure which shows the relationship between the thickness of a code switch, and resistance obtained by the measurement of FIG. It is explanatory drawing explaining the method to measure the relationship between the thickness of a foamed resin layer and a load when applying a load to the foamed resin layer used for the mat | matte sensor of FIG. 8, and making it deform | transform. It is a figure which shows the relationship between the thickness of a foamed resin layer, and the load obtained by the measurement of FIG.

DESCRIPTION OF SYMBOLS 1 Mat sensor 2 Upper surface sheet 3 Lower surface sheet 4 Foamed resin layer 5 Storage groove 6 Code switch 7 Insulator 8 Conductive member 11 Hollow part 40 Foamed resin layer 41 High foamed resin layer 42 Low foamed resin layer 51, 52, 53 Storage groove 61 , 62, 63 Code switch 81 Mat sensor 84 Foamed resin layer 85 Storage groove 86 Code switch

Claims (9)

A mat sensor provided with a cord switch that switches when a load is applied,
Between the flexible upper surface sheet and the lower surface sheet, a foamed resin layer that is elastically deformed by the load is provided,
At least the foamed resin layer is formed with a storage groove for storing the cord switch,
In the full length or a part of the storage groove, the width of at least a part of the storage groove when the foamed resin layer is not loaded is smaller than the width of the cord switch when no load is applied, and the cord is placed in the storage groove. By storing the switch, it is configured to hold the cord switch by elastic deformation of the storage groove of the foamed resin layer ,
The reaction displacement that the cord switch switches is smaller than the change point displacement at which the collapse displacement load of the foam resin layer changes suddenly, and the fracture displacement that the cord switch breaks is larger than the change point displacement of the foam resin layer. Matt sensor characterized by that.   2. The mat sensor according to claim 1, wherein a width of at least a part of the storage groove when no load is applied is 0.7 to 0.98 times a width of the cord switch when no load is applied.   The mat sensor according to claim 1 or 2, wherein the depth of the storage groove when no load is greater than the height of the cord switch when no load is applied.   The mat sensor according to any one of claims 1 to 3, wherein the storage groove has a curved groove portion, and the code switch is bent and disposed in the curved groove portion. The mat sensor according to any one of claims 1 to 4 , wherein an expansion ratio of the foamed resin layer is 5 to 100 times. The foamed resin layer has a high foamed resin layer and a low foamed resin layer, and until the reaction displacement that the cord switch switches, the high foamed resin layer is mainly crushed and deformed, and the cord switch breaks. The mat sensor according to any one of claims 1 to 5 , wherein the mat sensor is configured so that the low-foam resin layer mainly prevents deformation of the cord switch as it approaches. The mat sensor according to claim 6 , wherein a solid layer is used instead of the low foamed resin layer in the foamed resin layer. The cord switch is respectively held on an insulator having a hollow portion and an inner wall surface portion of the insulator defining the hollow portion, and is wired spirally along the longitudinal direction of the hollow portion while being spaced apart from each other mat sensor according to any one of claims 1 to 7, characterized in that it has a plurality of conductive members. A step of bonding a planar foamed resin layer on a flexible bottom sheet;
The cord switch is housed in a housing groove for housing the cord switch formed in the foamed resin layer, and is installed in a state where the cord switch is held by a portion of the housing groove having a width smaller than the width of the cord switch. Process,
Bonding a flexible upper surface sheet covering the foamed resin layer to the lower surface sheet;
I have a,
The reaction displacement that the cord switch switches is smaller than the change point displacement at which the crushing displacement load of the foam resin layer changes suddenly, and the fracture displacement that the cord switch breaks is smaller than the change point displacement of the foam resin layer. A method of manufacturing a mat sensor, wherein the mat sensor is enlarged .

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