JP4957025B2 - 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 includes 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 strain generating A screw portion that is arranged in the axial direction of the strain generating body so as to sandwich the body, and includes a screw head and a screw body portion, and the strain generating body has a cylindrical shape having a cavity in the axial direction, and the strain generating body The inner peripheral surface of the cavity and the outer peripheral surface of the screw head are welded and joined together.

  With the above-described configuration, a screw portion that is arranged in the axial direction of the strain generating body so as to sandwich the strain generating body and includes a screw head and a screw body portion, and the strain generating body and the screw head are integrated with each other. Therefore, for example, if the seat and the floor surface portion are connected via the screw portion, the attachment can be easily performed, and the work efficiency and the usability can be improved.

  In particular, the strain-generating body has a cylindrical shape with a cavity in the axial direction, and the inner peripheral surface of the strain-generating body's cavity and the outer peripheral surface of the screw head are welded and joined together to improve joint strength. it can. If the side surface of the strain body and the side surface of the screw head are simply joined by welding and integrated, it is easy to peel off in the tensile direction, but according to the above configuration, the screw head in the cavity of the strain body Since it is inserted and integrated, it is difficult to peel off.

  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 perspective view of the strain detection device, and FIG. 3 is a seat in which a vehicle seat and a floor surface portion are connected using the strain detection device. It is a side view of a unit.

  1 and 2, 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 a cross section of the screw barrel portion 8 having a cutout portion 9. The head 10 is welded and joined together. Moreover, as shown in FIG. 2, since the inner peripheral surface of the cavity 1 of the strain generating body 2 and the outer peripheral surface of the screw head 10 are welded and joined together, the joint strength can be improved. At this time, the screw head 10 is inserted into the cavity 1 of the strain body 2 and integrated, and the weld 7 appears in the axial direction. Further, the signal processing circuit is disposed in the case 6 attached to the outer peripheral surface of the strain body 2 and the screw portion 4.

  For example, as shown in FIG. 3, 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. At this time, a through hole matching the outer cross section of the screw body 8 is formed in the vehicle seat 12 and the floor surface portion 14, and the screw body 8 is inserted into the through hole and tightened with a nut 20.

  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 center of 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 strain body 2 has a cylindrical shape having a cavity 1 in the axial direction, and the inner peripheral surface of the cavity 1 of the strain body 2 and the outer peripheral surface of the screw head 10 are welded and joined together. The bonding strength can be improved. If the side surface of the strain body 2 and the side surface of the screw head 10 are simply welded and joined together, the strain body 2 can be easily peeled off in the tensile direction. Since the screw head 10 is inserted into and integrated with each other, it is difficult to peel off. In addition, as the shape of the screw part 4 arranged so as to sandwich the strain generating body 2, two notches 9 are provided so as to face the screw body part 8, as shown in FIG. As shown, it may be provided in a groove shape.

  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. Examples of the material of the strain generating body 2 include precipitation hardening stainless steel, and SUS630 is used when the strain generating body 2 and the screw portion 4 are made of the same material.

  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 Perspective view of the strain detection device Side view of a seat unit in which a vehicle seat and a floor surface portion are connected using the strain detection device. Perspective view of another strain detection device Perspective view of another 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 7 Welding part 8 Screw trunk part 9 Notch part 10 Screw head 12 Vehicle seat 14 Floor surface part 16 Rail part 18 Floor surface 20 Nut 22 Support part

Claims (3)

A columnar strain generating body that generates strain due to a load, a resistance element that is arranged on a circumferential surface of the strain generating body and has a resistance value that changes according to the amount of strain, and an axis of the strain generating body that sandwiches the strain generating body A screw portion including a screw head portion and a screw body portion, and the strain body is a cylinder having a cavity in the axial direction, and an inner peripheral surface of the cavity of the strain body and the screw head portion A strain detection device in which the outer peripheral surface of each is welded and joined together. The strain detection apparatus according to claim 1, wherein a load is applied to the screw portion so that a load direction is an axial direction of the strain generating body, and a strain amount due to the axial force of the strain generating body is detected. The load is applied to the screw portion so that the load direction is perpendicular to the axial direction of the strain generating body, and the amount of strain due to the shear force or bending moment of the strain generating body is detected. The distortion detection apparatus as described.

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