JP5887954B2 - Strength tester - Google Patents

Description

  The present invention relates to a strength tester for measuring the strength of spot welding.

For joining two metal plates, a spot welding method is widely used because of its simple work and equipment and strength. Furthermore, spot welding is also used for coupling nuts and male screws. This spot welding strength test method is established in Japanese Industrial Standard JISZ3136, and describes that a tensile tester defined in JISZ2241 is used.
However, tensile testing machines for material testing are expensive and are therefore mainly installed in research institutions and rarely used at production sites. In view of quality control, spot welding manufacturers need an inexpensive strength tester that can be used easily at the production site.

Japanese Patent Laid-Open No. 06-148047 JP 2003-344248 A JP 2010-151507 A

  As shown in FIG. 9, the conventional tensile testing machine used as a conventional material testing machine is mainly a system in which the upper head moves up and down using a ball screw or the like, and is operated using a motor or hydraulic equipment as a drive source ( (See Patent Documents 1 and 2). Therefore, it becomes a large structure and becomes expensive equipment.

  In spot welding, there are many examples in which two metal plates are mainly joined, but they are also widely used for joining welding nuts and metal plates, welding screws and metal plates. There is a need for an apparatus that can easily perform these three types of bond strength tests.

  When it is used only as a strength test for spot welding, there is no need to guarantee the accuracy as in a tensile tester for material tests at research institutions.

  The inventors of the present invention have previously proposed Patent Document 3, but the present invention can be further evolved to perform a spot welding strength test for nuts and male screws simultaneously with a spot welding strength test for metal plates. Also, a small and inexpensive strength tester that can be installed at the spot welding production site is provided.

  However, it is a challenge to create a system that can monitor and calibrate the accuracy of a strength tester whose accuracy is unknown.

The present invention solves the above problems by the following configuration.
<Configuration 1>
The metal plate test piece spot-welded with a strength tester that applies force by raising the ram of the hydraulic jack placed on the base is held by gripping teeth A and gripping teeth B by tightening bolts .
The spot-welded nut test piece is bolted to the nut, placed on a spacer placed on the bottom of the lifting frame , and held.
The spot-welded male thread test piece is attached with a jig nut, the lower gripping tooth B is removed , a lower unit having a slide plate with a U-shaped groove is attached, and the upper gripping tooth B is removed. And attach and hold an upper block having a modified hole into which the jig nut is fitted ,
The elevating frame lower part and the elevating frame upper part are connected with a pair of elevating posts and rise together with the ram, and give tensile force or compressive force to the test piece
A pressure transducer for converting the hydraulic pressure of the hydraulic jack into an electrical signal;
A digital indicator that digitally displays the maximum value of tensile force or compressive force output from the pressure transducer;
A correction value obtained by a calibration measuring instrument is input to the digital indicator,
The strength tester further comprises a printer that is electrically connected to the digital display and prints data input to the digital display.

  According to the present invention, it is possible to provide an inexpensive strength tester that can be easily and easily tested even at a processing site in a factory. Spot welding quality control becomes easier and leads to improved quality.

It is an Example which shows the strength test of the metal plate test piece 1 spot-welded. It is a right view of FIG. 1 Example. It is explanatory drawing which shows the state which attached the measuring device 30 for a calibration of the Example of FIG. It is an Example which shows the strength test of the nut test piece 24 spot-welded. It is the partial view seen from the right side surface which shows the detail of the strength test of the nut test piece 24 spot-welded. It is an Example which shows the strength test of the external thread test piece 31 spot-welded. (A) -1, (a) -2 is explanatory drawing which attached the jig nut 33 to the external thread test piece 31, (a) -1 shows a cross-sectional state. FIG. 4B is a detailed view of the male screw holder 32 used for the strength test of the male screw test piece 31. (C) shows a state in which the slide rail 34 is inserted and set on the upper surface of the male screw test piece 31. 1 is a block diagram showing a hydraulic jack 7, a pressure converter 14, a digital indicator 15, and a printer 16. FIG. It is a front view which shows the conventional tensile testing machine used as a material test.

  The embodiment will be described with reference to the accompanying drawings.

FIG. 1 is an example showing a strength test of a spot-welded metal plate test piece 1.
As shown in FIG. 1, a hydraulic jack for applying a tensile force to the metal plate test piece 1 through a pair of upper and lower gripping teeth A2 and B3, which grip the spot-welded metal plate test piece 1 and these gripping teeth. 7 and the hydraulic jack 7 are provided with gauge holes for displaying the pressurization with a hydraulic gauge. A pressure converter 14 for changing the hydraulic pressure into an electric signal as strength is attached to the gauge hole. The digital display meter 15 that digitally displays the maximum intensity value output from the printer and the printer 16 that is electrically connected to the digital display meter 15 and prints data input to the digital display meter. .

  A manual hydraulic jack 7 is used as a drive source. The lower part 6 of the elevating frame is pushed up by the hydraulic jack 7, and a tensile force is applied to the metal plate test piece 1 gripped by a pair of upper and lower gripping teeth A2 and B3, thereby breaking the metal plate test piece 1. A pressure meter 14 mounted in the gauge hole of the hydraulic jack 7 converts the hydraulic pressure into an electrical signal, and the display meter 15 digitally displays the electrical signal as intensity. This display is printed by the printer 16 and remains as a record.

  The printer 16 has a function of printing the maximum value of the intensity data output from the pressure converter 14 and printing the average value, standard deviation, and the like of each aggregate of test pieces.

  The hydraulic pressure of the gauge hole of the hydraulic jack 7 is converted into an electric signal by the pressure transducer 14 and the electric signal is shown as an intensity on the digital indicator 15, but the hydraulic jack 7 is an instrument intended to push up a heavy object and its accuracy is unknown. It is. Therefore, it is necessary to input a correction value for correcting the difference with the true numerical value to the digital display meter 15. For the true numerical value, the calibration measuring instrument 30 shown in FIG. 2 is used. By comparing the numerical value of the digital indicator 15 on which the numerical value of the hydraulic jack 7 is displayed with the numerical value of the digital indicator 37 of the calibration measuring instrument 30 and inputting and calibrating the correction value, the hydraulic pressure that is not a measuring instrument is obtained. The accuracy of the jack 7 is also increased. Compared to a hydraulic gauge in which an analog pressure gauge is directly attached to the gauge hole of a hydraulic jack sold by a hydraulic jack manufacturer or the like and the hydraulic pressure is displayed as it is, the accuracy is much better.

When the release knob 8 is locked and the operation rod 9 of the hydraulic jack 7 is operated up and down, the ram 10 is raised, and the lower part 6 of the lifting frame connected to the gripping teeth A2 and B3 is pushed up, and the metal plate test piece By applying a tensile force to 1, the metal plate test piece 1 breaks.
The release knob 8 is turned to the right and locked to enable the operation of the ram 10 of the hydraulic jack 7. Further, when the release knob 8 is turned counterclockwise and released, the hydraulic pressure of the hydraulic jack 7 is released and the ram 10 is lowered.

  The tensile strength of the hydraulic jack 7 is converted into an electrical signal by the pressure transducer 14 and displayed on the digital indicator 15 with a numerical value of kN. When the metal plate test piece 1 breaks, the numerical value of the digital indicator 15 displays the maximum value of strength. This display is printed by the printer 16 and recorded as a record.

  The printer 16 prints the maximum value of the tensile force data output from the pressure transducer 14 via the digital indicator 15 and also prints the average value, standard deviation, etc. of each aggregate of test pieces. It is what has.

  As shown in FIG. 8, advanced analysis is possible by connecting to a personal computer separately from the printer 16. Furthermore, the data can be stored in a memory card and analyzed by another computer.

  By releasing the release knob 8, the hydraulic pressure of the hydraulic jack 7 is released, and the ram 10 and the lifting frame upper part 11 and the lifting frame lower part 6 that are integrally connected are lowered. The test piece 1 thus broken is removed, and the test is completed.

The strength tester of the present invention can further perform a strength test of the nut test piece 24 spot-welded to a metal plate.
The strength test of the nut test piece 24 includes an indentation peeling test as shown in Japanese Industrial Standard JISB1196. Quality control of strength is also an important issue for welded nuts that are spot welded. In FIG. 4, the spacer 22 that holds the nut test piece 24 to which the bolt 25 is mounted is placed on the plate of the lower frame 6. The lower part 6 of the ascending frame is raised by the operation of the hydraulic jack 7, the bolt 25 hits the fixed plate 23, and further rises so that the weld nut is peeled off. . Since the correction value has already been input by calibration, the accuracy is equivalent to the content described above.

  FIGS. 5A and 5B are explanatory views showing the details of the strength test of the nut test piece 24 spot-welded in a partial view of FIG. 4 viewed from the right side. FIG. 5A shows a state in which the spacer 22 holding the nut test piece 24 to which the bolt 25 is mounted is placed on the plate of the lower frame lower part 6 as in FIG. FIG. 5 (b) shows the state in which the lower part 6 of the rising frame is raised and the bolt is abutted against the fixing plate 23, the nut test piece 24 starts to break, the weld nut and the metal plate are peeled off, and the strength is displayed. As shown in this figure, this strength test is an indentation peeling test itself described in Japanese Industrial Standard JISB1196. Further, the strength test of the welding bolt for projection welding, which has three projections on the flange portion established in JIS B1195, can be performed in the same manner as the nut test piece 24.

  As shown in FIG. 6, the strength tester of the present invention can further perform a strength test of a male screw test piece 31 spot-welded to a metal plate. Spot welding studs such as spot welding male threads have a small triangular projection at the center of the tip, and are a method of projection welding to a metal plate. Unlike the weld bolt having three protrusions on the brim portion defined in JISB1195 described above, no hole is required in the metal plate. In the strength test of the male screw test piece 31, a holder 32 of the male screw test piece 31 shown in FIG. The test procedure is described below.

  In this test, after removing the upper and lower gripping teeth B3 of FIG. 1, the male screw holder 32 of FIG. 7B is fixed to the upper and lower gripping teeth A2 as shown in FIG. The male screw holder 32 is composed of an upper block 35 and a lower unit 36, which are vertically separated, and each is fixed to the upper and lower gripping teeth A2 by two bolts.

  Next, as shown in FIGS. 7 (a) -1 and (a) -2, the jig nut 33 is attached to the male thread test piece 31 and set in the deformed hole 38 of the upper block 35 attached to the strength tester main body 4. Then, the slide plate 34 is slid in the direction of the arrow in FIG. 7B and inserted into the two portal plates 39. FIG. 7C is an explanatory view showing a state in which the inserted slide plate 34 having a U-shaped groove is set on the upper surface of the metal plate of the male screw test piece 31. Here, when the release knob 8 is locked and the operating rod 9 of the hydraulic jack 7 is moved up and down, the ram 10 rises and the jig nut 33 rises together with the upper block 35. A tensile force is applied to the pressed metal plate, the male screw and the metal plate are broken, and the maximum value of the strength is displayed on the digital indicator 15 in kN. Again, since the correction value has already been input by calibration, the accuracy is equivalent to the content described above.

  Because it is compact and does not take up space, it can be easily tested and is inexpensive, so it can be used as a spot welding strength test at the factory processing site. The spot welding strength test for welded nuts and welded screws can be performed easily at the same time as the metal plate test piece, which can contribute to improving the quality of spot welding related parts.

1 Metal plate test piece 2 Gripping teeth A
3 grasping teeth B
4 Strength tester body
5 Base 6 Lower part of lifting frame 7 Hydraulic jack 8 Release knob 9 Operation rod 10 Ram 11 Upper part of lifting frame 12 Lifting post 13 Post guide 14 Pressure transducer 15 Digital indicator 16 Printer
20 Tightening bolt 22 Spacer 23 Fixing plate 24 Nut test piece 25 Bolt 26 Body frame 30 Calibration instrument 31 Male thread test piece 32 Male screw holder 33 Jig nut 34 Slide plate 35 Upper block 36 Lower unit 37 Calibration instrument Digital display meter 38 Profile hole
39 Portal plate

Claims (1)

The metal plate test piece spot-welded with a strength tester that applies force by raising the ram of the hydraulic jack placed on the base is held by gripping teeth A and gripping teeth B by tightening bolts .
The spot-welded nut test piece is bolted to the nut, placed on a spacer placed on the bottom of the lifting frame , and held.
The spot-welded male thread test piece is attached with a jig nut, the lower gripping tooth B is removed , a lower unit having a slide plate with a U-shaped groove is attached, and the upper gripping tooth B is removed. And attach and hold an upper block having a modified hole into which the jig nut is fitted ,
The elevating frame lower part and the elevating frame upper part are connected with a pair of elevating posts and rise together with the ram, and give tensile force or compressive force to the test piece
A pressure transducer for converting the hydraulic pressure of the hydraulic jack into an electrical signal;
A digital indicator that digitally displays the maximum value of tensile force or compressive force output from the pressure transducer;
A correction value obtained by a calibration measuring instrument is input to the digital indicator,
The strength tester further comprises a printer that is electrically connected to the digital display and prints data input to the digital display.