JPH0641890B2 - Stress distribution sensor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a stress distribution detection sensor, and more particularly to a stress distribution detection sensor in which the resolution of stress distribution applied to an electrode member of the sensor is improved.

(Prior Art) As a conventional sensor for detecting the stress distribution of a surface pressure, a spring, a contactor combining springs, or a mechanical one using a strain gauge is used to detect a local surface pressure. Was there.

Recently, instead of the above mechanical sensor, a pressure-sensitive conductive rubber is sandwiched between polyethylene electrode films printed with a silver circuit pattern, and the magnitude and pressure distribution of the pressure applied to the electrodes can be obtained. The sensor was developed as a tactile sensor, for example polymer digest 9,
P107 (1985).

(Problems to be Solved by the Invention) The above-mentioned sensor can detect the pressing force from the change of the current value when the electric resistance value gradually decreases as the pressing force increases and a constant voltage is applied. . Therefore, it is possible to measure the stress distribution applied to the predetermined surface of the sensor. However, in the pressure-sensitive conductive rubber sandwiched between the electrode films, current flows mainly between the terminals of the shortest distance set in the electrode film, but not only that, but a circuit is also formed between various terminals. To be done. When the sensor receives a local pressing force, the currents flowing from the output terminals interfere with each other, so that an accurate value cannot be output and the stress distribution resolution is poor.

The present invention addresses such a problem, and provides a stress distribution detection sensor that can accurately detect a pressing force received by a sensor without being electrically interfered with each other and that is excellent in resolution of stress distribution. The purpose is.

(Means for Solving the Problem) That is, the stress distribution detecting sensor according to the present invention is a stress distribution detecting sensor in which a pressure sensitive conductive rubber is interposed between two electrode members, and the pressure sensitive conductive rubber is used as a sheet. -Shaped electrical insulators, which are arranged in a separated state, are protruded from the electrical insulators, and electrode members in which terminals are dispersed are laminated on at least one side of the pressure-sensitive conductive rubber, and the terminals are laminated. Is brought into contact with a pressure-sensitive conductive rubber.

(Function) In the stress distribution detection sensor of the present invention, the pressure-sensitive conductive rubber is arranged in a sheet-like electric insulator in a separated state, and the pressure-sensitive conductive rubber is projected from the electric insulator so that the surface of the rubber serves as an electrode member. Since they are in contact with each other, the local surface pressure received by the electrode member is converted into a current value or a voltage value by the deformation of the pressure-sensitive conductive rubber that exists independently at that site, and is converted from each terminal. Further, since the pressure-sensitive conductive rubber is output at predetermined positions, the pressure at each position is accurately detected without being affected by the electrical interference of the adjacent rubber bodies at each position.

Moreover, since each pressure-sensitive conductive rubber is not only held in a stable state by the electric insulator but also deformed freely without being greatly affected by the electric insulator, the sensor of the present invention detects even more accurate stress. can do.

(Examples) Specific examples of the present invention will be described below with reference to the accompanying drawings.

1 is a partial sectional perspective view of the stress distribution detecting sensor of the present invention, and FIG. 2 is a plan view of a pressure-sensitive conductive layer used in the stress distribution detecting sensor of FIG. In the stress distribution detection sensor (1), the pressure-sensitive conductive layer (2) is located in the core portion, the electrode members (3) and (3) are laminated on the upper and lower surfaces thereof, and the electrode member (3) ( 3) Cover material to protect
(4) (4) is covered.

The pressure-sensitive conductive layer (2) is a through-hole (5) provided at a predetermined position of a sheet-like electric insulator (5) made of a rubber member such as natural rubber, SBR, CR or silicon rubber, or an elastic body such as polyurethane. A chip-shaped pressure-sensitive conductive rubber (7) is arranged in 6). The pressure-sensitive conductive rubbers (7) are separated and independent from each other and protrude from the surface of the sheet-like electric insulator (5). For this reason, the stress distribution detection sensor (1) has a more accurate stress because the pressure-sensitive conductive rubber (7) present in each part is freely deformed without being greatly affected by the electric insulator (5). Can be detected. In this case, the sheet-like electric insulator (5) has a function as a holding member for stably positioning the pressure-sensitive conductive rubber (7) in a separated state.

Further, the electrode member (3) located on the upper side may have flexibility in which the terminals (8) are dispersed, while the electrode member (3) located on the lower side may be a rigid electrode plate. This pressure sensitive conductive layer
(2) has a thickness of about 0.1 to 5 mm.

The dispersion density of the pressure-sensitive conductive rubber (7) can be freely changed, and the higher the dispersion density, the higher the resolution of the stress position.

The pressure-sensitive conductive rubber (7) is not particularly limited as long as the resistance value is deformed according to the applied pressure, for example, natural rubber having electric insulation, polybutadiene rubber, polyisoprene rubber, styrene-Budagen copolymer Combined rubber, butyl rubber, chloroprene rubber, acrylonitol-butadiene copolymer rubber, ethylene-propylene copolymer rubber, silicone rubber, etc. are conductive carbon black such as furnace black, acetylene black, thermal black, channel black, etc. Known substances are mixed,
Further, various conductive materials such as metal powder, metal fiber or non-metal inorganic short fiber, powder or whiskers are mixed. Among these, in the present invention, a pressure-sensitive conductive rubber having a small hysteresis against repeated pressure deformation is preferable, and as an example of a rubber satisfying this, for example, carbon black or non-metal inorganic short fiber is used for the rubber,
A mixture of powder or whiskers is preferable.

The short fibers are made of ceramics such as silicon carbide (SiC), glass and silicon nitride (Si ₃ N ₄ ) and have a length of 100 μm to 10 mm and a diameter of 0.3 to 30 μm. It is called a ceramic powder of 0.5 μm to 100 μm, for example, silicon carbide (SiC), titanium carbide (TiC), boron carbide (B ₄ C), tungsten carbide (W
C) and other carbides, silicon nitride (Si ₃ N ₄ ), aluminum nitride (AlN), boron nitride (BN), titanium nitride (TiC) and other nitrides, and alumina (Al ₂ O ₃ ), zirconia (ZrO ₂ ). Oxides such as beryllia (BeO), and most preferably silicon carbide or silicon nitride.

Furthermore, as whiskers, α-silicon carbide (α-Si
C), β-silicon carbide (β-SiC), silicon nitride (Si ₃ N ₄ ),
α-alumina (Al ₂ O ₃ ), titanium oxide, zinc oxide, tin oxide, graphite, Fe, Cu, Ni, etc., having a diameter of 0.05 to 3 μm,
It is a needle-shaped single crystal having a length of about 5 to 500 μm. When adding the inorganic filler to rubber,
It is also possible to previously treat with a silane coupling agent, a titanium coupling agent, or the like, or to add a silane coupling agent or a titanium coupling agent when mixing with rubber.
This further enhances the reinforcing effect and improves the dispersibility in rubber.

The amount of the inorganic filler added is 1 to 80 parts by weight, preferably 5 to 40 parts by weight, relative to 100 parts by weight of rubber. If 1 part by weight or less of the inorganic filler is used, The exposure effect decreases and the resistance value when not pressurized decreases, and the electrical resistance at a pressure of 0.5 kg / cm ² is also high, resulting in poor conductivity. On the other hand, when it exceeds 80 parts by weight, it is due to the effect of rubber. The rate of resistance change during pressurization becomes small.

Incidentally, the pressure-sensitive conductive rubber (7) used in the present invention is not limited to the above specific one as described above,
Any material may be used as long as the resistance value changes according to the applied pressure. An example of the electrode member (3) is shown in FIG. 1, in which point-like terminals (8) exposed in a separated state are present in a flexible synthetic resin sheet having electrical insulation. The lead wire (9) is embedded in each terminal (8) in a connected state. The terminal (8) is in contact with the pressure-sensitive conductive rubber (7) embedded in the sheet-like electric insulator (5) of the pressure-sensitive conductive layer, and against pressure change of the pressure-sensitive conductive rubber (7). Detect changes in current or voltage.

In the sensor of the present invention, the electrode member is the same as above.
(3) may be laminated on the upper and lower surfaces of the pressure-sensitive conductive layer (2), but unlike this, a metal electrode sheet body, electrode plate or electrode thin film that does not intersperse point-like terminals on one surface An equal electrode member (3) can be used.

The surface of the electrode member (3) (3) has a cover layer for protecting it.
The cover layer (4) is laminated, but the cover layer (4) is made of a foam, a synthetic resin film or the like, and it is not always necessary to laminate the cover layer in the sensor of the present invention.

The stress distribution detection sensor (1) having such a configuration,
For example, to detect the stress applied to the electrode member (3) of the sensor by its own weight due to the weight of an article having a complicated curved surface or its distribution, or to use as a tactile sensor to detect the force holding the same article and its distribution. Can be done.

(Effect) As described above, in the stress distribution detection sensor of the present invention, the pressure-sensitive conductive rubber is arranged in a sheet-like electric insulator in a dispersed state and protruded from the electric insulator. At least one of the conductive rubbers is brought into contact with each terminal provided on the electrode member, and by blocking the electrical interference of the adjacent pressure-sensitive conductive rubbers, the surface pressure of each part that the sensor receives can be accurately measured. It is possible to convert it into a current value or a voltage value and it is excellent in the ability to disperse the stress distribution, and it is also possible to change the ability to decompose the stress distribution by changing the dispersion density of the pressure-sensitive conductive rubber. The shape of the object and the area of stress concentration can be known from the result of the stress distribution, and each pressure-sensitive conductive rubber is not only held in a stable state by the electrical insulator, but also electrically insulated. Since it is freely deformed without being greatly affected by the body, there is an effect that more accurate stress can be detected.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional perspective view of the stress distribution detection sensor of the present invention, and FIG. 2 is a plan view of a pressure-sensitive conductive layer used in the stress distribution detection sensor of FIG. (1) …… Stress distribution detection sensor (3) (3) …… Electrode member (5) …… Electrical insulator (7) …… Pressure-sensitive conductive rubber (8) …… Terminal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hajime Kakiuchi 5-chome, Mizuho-cho, Itami City, Hyogo Prefecture 28 (72) Inventor Kamejuro Yata 4-8-510 Wakamiya-cho, Ashiya City, Hyogo Prefecture Masayuki Mori (56) Reference Reference JP-A-56-142430 (JP, A) JP-A-59-175992 (JP, A)

Claims (1)

[Claims] 1. A stress distribution detecting sensor having a pressure-sensitive conductive rubber interposed between two electrode members, wherein the pressure-sensitive conductive rubber is arranged in a sheet-like electric insulator in a separated state. An electrode member that is projected from the electrical insulator and has each terminal dispersed therein is laminated on at least one side of the pressure-sensitive conductive rubber to bring the terminal into contact with the pressure-sensitive conductive rubber, and at least the electrode member. A stress distribution detection sensor, characterized in that one is made flexible.