JP4816158B2 - Strain detector - Google Patents

Description

  The present invention relates to a strain detection device for measuring a load on a vehicle seat or the like.

  Hereinafter, a conventional strain detection apparatus will be described.

  A conventional strain detection device includes a plate-like strain generating body having a plurality of through holes, a resistance element that is disposed between the through holes of the strain generating body and has a resistance value that varies depending on the amount of strain, and the resistance element. And a signal processing circuit connected to each other.

  For example, if the strain detection device is attached between the vehicle seat and the floor portion, the load of the person sitting on the vehicle seat can be measured. Among the plurality of through holes provided in the strain body, a part of the vehicle seat is inserted into the inner through hole to connect the strain body and the vehicle seat, and a part of the floor portion is connected to the outer through hole. To insert and connect the strain generating body and the floor surface portion (for example, a part of the vehicle seat or a part of the floor surface portion is used as a threaded portion and tightened with a nut via the strain generating body). Then, when a load is applied to the vehicle seat, the strain generating body is distorted and the resistance value of the resistance element changes, so that the load can be measured by processing this with a signal processing circuit. In this case, since the strain body is connected to both the vehicle seat and the floor portion, the load in the compression direction and the load in the tension direction can be measured.

  As the shape of such a strain generating body, there is a cylindrical shape in addition to a plate shape, and both are those in which a strain detecting device is attached by combining a plurality of attachment parts.

As prior art document information related to the invention of this application, for example, Patent Document 1 and Patent Document 2 are known.
JP 2003-240633 A JP-A-6-207865

  The above-described conventional strain detection device has a problem in that a plurality of mounting parts are required for mounting the strain detection device, and the assembly work efficiency and usability are poor.

  SUMMARY OF THE INVENTION The present invention solves the above-described problems, and an object of the present invention is to provide a strain detection device that has few attachment parts and is easy to work and easy to use.

In order to achieve the above object, the present invention provides a columnar strain generating body that generates strain due to a load, a resistance element that is disposed on a peripheral surface of the strain generating body and has a resistance value that varies depending on the amount of strain, and the resistance element And a signal processing circuit for detecting a strain amount of the strain generating body, and a screw portion is arranged in an axial direction of the strain generating body so as to sandwich the strain generating body, and the strain generating body and the screw portion And the signal processing circuit is arranged in a case attached to the strain generating body or the screw portion, and the direction of the load is a direction perpendicular to the axial direction of the strain generating body. As described above, the load is applied to the screw portion to detect the amount of strain caused by the shearing force or bending moment of the strain generating body .

  With the above configuration, the screw portion is arranged in the axial direction of the strain generating body so as to sandwich the strain generating body, and the strain generating body and the screw portion are integrated with each other. If it connects with a floor surface part, attachment will become easy and work efficiency and usability can be improved. In particular, since the signal processing circuit is disposed in the case attached to the strain body or the screw portion, the connection between the resistance element and the signal processing circuit can be routed short, making it less susceptible to noise and improving the sensitivity.

  Hereinafter, the invention described in all claims of the present invention will be described with reference to the drawings.

  1 is a cross-sectional view of a strain detection device according to an embodiment of the present invention, FIG. 2 is a side view of the strain detection device, FIG. 3 is a top view of the strain detection device, and FIG. 4 is a front view of the strain detection device. FIG. 5 is a side view of a seat unit in which the vehicle seat and the floor portion are connected using the strain detection device.

  1 to 4, a strain detection apparatus according to an embodiment of the present invention includes a columnar strain generating body 2 that generates strain due to a load, and a resistance that is arranged on the outer peripheral surface of the strain generating body 2 according to the amount of strain. A resistance element whose value changes and a signal processing circuit which is connected to the resistance element and detects the strain amount of the strain generating body 2 are provided. The strain generating body 2 has a cylindrical shape having a cavity 1 in the axial direction, and screw portions 4 are arranged above and below in the axial direction of the strain generating body 2 so as to sandwich the strain generating body 2. The screw portion 4 has a screw head portion 10 having a diameter larger than that of the screw barrel portion 8, and the strain body 2 and the screw head portion 10 of the screw portion 4 are welded and joined together. Yes. The signal processing circuit is arranged in a case 6 attached to the outer periphery of the strain body 2 and the screw portion 4.

  For example, as shown in FIG. 5, if this strain detection device is attached between the vehicle seat 12 and the floor surface portion 14, it is possible to measure the load of a person sitting on the vehicle seat 12.

  The vehicle seat 12 is provided with a through-hole into which the screw body 8 of the screw portion 4 is inserted, and the floor surface portion 14 is inserted into the rail portion 16 attached to the floor surface 18. A through hole is provided, and the axial direction of each through hole is provided to be perpendicular to the floor surface 18. One screw body portion 8 is inserted into the through hole of the vehicle seat 12, and the other screw body portion 8 is inserted into the through hole of the rail portion 16, and is tightened with a nut 20 to attach the strain body 2 and the screw portion 4. The vehicle seat 12 and the floor surface portion 14 are connected to each other.

  Then, when a load is applied to the vehicle seat 12, the load is applied to the screw portion 4 so that the load direction is the axial direction of the strain generating body 2 (vertical direction with respect to the floor surface 18), and the shaft of the strain generating body 2 is The strain generating body 2 is distorted due to the force. Since the resistance value of the resistance element changes due to the strain of the strain generating body 2, the load can be measured by processing this with a signal processing circuit.

  Since the screw part 4 is formed so as to sandwich the strain generating body 2 with the above configuration, for example, when the vehicle seat 12 and the floor surface part 14 are connected via the screw part 4, an attachment component is provided. It can be installed with little and simple, and the work efficiency and usability can be improved. In particular, since the signal processing circuit is disposed in the case attached to the strain body or the screw portion, the connection between the resistance element and the signal processing circuit can be routed short, making it less susceptible to noise and improving the sensitivity.

  In addition, since the strain body 2 and the screw portion 4 are integrated with each other, breakage at the boundary portion between the strain body 2 and the screw portion 4 can be suppressed even when a load is applied to the vehicle seat 12. In particular, from the several tens of kilograms at the time of weight detection to about 1 ton at the time of vehicle collision detection, it is possible to suppress breakage at the boundary between the strain generating body 2 and the screw portion 4 without impairing the detection capability, and further to vehicle destruction The breakage at the boundary between the strain body 2 and the screw portion 4 can be suppressed even for such a load of several tons. The strain body 2 and the screw portion 4 may be welded and joined together, or a member made of the same material may be processed. As the material of the strain body 2 and the threaded portion 4, SUS301 having an austenitic work-hardening property that is rich in ductility and toughness and having excellent weldability, SUS630 having precipitation hardenability, or good corrosion resistance and weldability. Examples thereof include ferrite type SUS430. The SUS301, SUS630, and SUS430 are stainless steel standards defined by JIS (Japanese Industrial Standards).

  In addition, since the strain body 2 has a cylindrical shape having through holes in the axial direction, the outer peripheral surface area of the strain body 2 is increased and the arrangement area of the resistance element is increased without impairing the ease of distortion of the strain body 2. It is possible to ensure the integrated strength between the screw portion 4 and the strain body 2. In the case where the strain body 2 is a simple column, if the diameter of the strain body 2 is increased in order to secure the arrangement area of the resistive element, the strain body 2 may be less susceptible to stress and the sensitivity may be reduced. Thus, if the strain body 2 is cylindrical, it is easy to receive stress, and the fall of a sensitivity can also be suppressed. Further, if a stepped portion or a tapered portion is formed in the screw head portion 10 of the screw portion 4 so as to match the inner diameter of the through hole, the axis of the strain generating body 2 and the axis of the screw portion 4 are accurately coaxial. Therefore, it is possible to suppress the bias of the distortion of the strain generating body 2 due to the positional deviation and improve the sensitivity.

  Moreover, when connecting the vehicle seat 12 and the floor surface part 14, you may make it show in FIGS. The vehicle seat 12 is provided with a through-hole for inserting the screw body portion 8 of the screw portion 4 in the lower portion thereof, and the screw body portion 8 is inserted into the support portion 22 attached to the floor surface 18 in the floor surface portion 14. A through hole is provided, and the axial direction of each through hole is provided so as to be horizontal with respect to the floor surface 18. One screw body portion 8 is inserted into the through hole of the vehicle seat 12, and the other screw body portion 8 is inserted into the through hole of the support portion 22, and the strain body 2 and the screw portion 4 are fastened together with the nut 20. The vehicle seat 12 and the floor surface portion 14 are connected to each other.

  Then, when a load is applied to the vehicle seat 12, the load is applied to the screw portion 4 so that the load direction is perpendicular to the axial direction of the strain body 2, and the shear force of the strain body 2 or The strain body 2 is distorted due to the bending moment. Since the resistance value of the resistance element changes due to the strain of the strain generating body 2, the load can be measured by processing this with a signal processing circuit. In particular, since the height between the vehicle seat 12 and the floor surface portion 14 can be reduced by simply selecting the diameter of the strain generating body 2 according to the specifications, the seat of the vehicle seat 12 that differs depending on the vehicle type can be obtained. The height of the surface can be set low beforehand. That is, it becomes easy to adjust the height of the line of sight of the person sitting on the seating surface.

  The relationship between the resistance element pattern (deployed pattern) arranged on the strain body 2 and the output sensitivity is as shown in FIG. 9 and is connected between the power supply voltage (Vcc) and the ground electrode (GND). Based on the output voltage (V +), the output voltage (V−), and the resistance element patterns R1, R2, R3, and R4, a predetermined output sensitivity corresponding to the strain of the strain generating body 2 can be obtained. The output sensitivity is such that the patterns R1 and R4 and the patterns R2 and R3 are arranged so as to face each other on the outer peripheral surface of the strain generating body 2 and, for example, the patterns R1 and R4 are disposed below the strain generating body 2 ( If the rotation angle of attachment is 0 degree) and the patterns R2 and R3 are arranged on the upper side of the strain body 2 (the rotation angle of attachment is 180 degrees), the maximum value is obtained.

  Furthermore, in one embodiment of the present invention, the strain detection device is used for load measurement of the vehicle seat 12, but may be used for torque measurement.

  As described above, the strain detection device according to the present invention has few attachment parts, is easy to install, has good work efficiency and convenience, and can be applied to various devices as a sensor for measuring a load.

Sectional drawing of the distortion | strain detector in one embodiment of this invention Side view of the strain detector Top view of the strain detector Front view of the strain detector Side view of a seat unit in which a vehicle seat and a floor surface portion are connected using the strain detection device. Side view of other seat units Enlarged view of part A in FIG. Front sectional view of part A in FIG. Characteristic waveform diagram showing the relationship between the resistance element pattern and sensitivity

Explanation of symbols

DESCRIPTION OF SYMBOLS 2 Strain body 4 Screw part 6 Case 8 Screw trunk part 10 Screw head 12 Vehicle seat 14 Floor part 16 Rail part 18 Floor surface 20 Nut 22 Support part

Claims (1)

A columnar strain generating body that generates strain due to a load, a resistance element that is arranged on the circumferential surface of the strain generating body and has a resistance value that changes according to the amount of strain, and a strain amount of the strain generating body that is connected to the resistance element. A signal processing circuit for detecting, wherein a screw portion is arranged in an axial direction of the strain generating body so as to sandwich the strain generating body, and the strain generating body and the screw portion are integrated with each other, and the signal processing The circuit is arranged in the case attached to the strain body or the screw portion, and the load is applied to the thread portion so that the direction of the load is perpendicular to the axial direction of the strain body. A strain detection apparatus for detecting a strain amount caused by a shearing force or a bending moment of the strain generating body .

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