JP2010066204A - Drop tester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To overcome the problem that the repeatability and the reliability of an impact test conducted by an impact tester in the prior art for confirming an impact resistance are lacked because it can not freely drop a test object, and can not apply a drop impact to the entire of the test object. <P>SOLUTION: The drop tester includes a placing member 6 with a maintaining member 8 for maintaining the test object 7 at a predetermined angle, a supporting table 2 for applying the drop impact to the test object 7, a holding member 4 for changing and holding a relative position between the supporting table 2 and the placing member 6, and a turning shaft 5 for turning the placing member 6 while the holding member 4 holds the desired relative position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drop test apparatus that drops a device or a package packed with the device from a desired distance.

  A drop test device for predicting in advance defects such as damage caused by the product transportation process and the purchaser who purchased the product accidentally dropped or collided with a foreign object. Is popular. In particular, in recent years, the use of portable products is remarkable due to the reduction in size and weight of products and the personalization of products, and the need to conduct impact resistance tests on products is increasing.

  In such a drop tester, when a drop impact is applied to a product, applying the impact in the same posture reduces the drop height dependency of the impact on the product due to the impact by changing the drop height. It has been requested as an application for testing.

  For example, Patent Document 1 is known as a drop test apparatus that satisfies the above-described requirements. In Patent Document 1, a test object is placed on a tapered portion of a tapered holder that includes a through hole provided in a central portion and a tapered portion having an inclination of a predetermined angle around the through hole, and tested from a predetermined height. A drop impact test apparatus is disclosed that drops together with a tapered holder on which an object is placed toward a collision receiving plate in which a through hole is loosely inserted, and observes a drop impact between the collision receiving plate and a test object.

With this configuration, the specimen can be made to collide with the impact receiving plate while being held by the tapered holder, so that the specimen can be allowed to fall freely and collide with the collision surface while keeping the falling posture of the specimen constant. The strain, stress, and the like caused by the impact can be accurately measured with good reproducibility. In addition, by adjusting the inclination angle of the taper portion, it is possible to suppress the test specimen from rising from the tapered holder during the fall and the collapse of the posture of the test specimen caused by the air resistance.
JP 2003-166922 A

  However, the technique disclosed in Patent Document 1 has the following three main problems. First, since the test object is placed on the taper portion of the tapered holder, it is easily affected by the inclination of the taper part, and it is difficult to place the test object under the same conditions and lacks reproducibility. Secondly, the location where the test object collides and a drop impact is applied is a collision receiving plate that loosely inserts a part of the through hole of the tapered holder. It cannot be measured. Third, since the test object is dropped together with the tapered holder in the process of dropping, it is impossible to measure the effect of the natural fall of the test object alone.

  In order to solve the above-described problems, the impact test apparatus shown in FIG. The impact test apparatus 11 shown in FIG. 2 is supported by a column 13 fixed to a support 12, a height adjusting unit 14 that engages with the column 13 and maintains a predetermined height, and a height adjusting unit 14. A configuration with a mounting table 16 that is pivotally supported by a rotating shaft 15 and on which a test object 17 is mounted is conceivable. The difference between the impact test apparatus 11 and Patent Document 1 is a configuration in which only the test object 17 can be naturally dropped by rotating the mounting table 16 around the rotation shaft 15.

  The operation of the impact test apparatus 11 will be described with reference to FIG. As shown in FIG. 1A, the test object 17 is placed on the placing table 16. Next, in a state where the test object 17 is mounted on the mounting table 16, as shown in FIG. 5B, for example, a predetermined initial speed is applied only to the mounting table 16 and the acceleration G is faster than the natural fall acceleration g. The height adjustment unit 14 is moved in the direction of the support base 12. By executing this operation for a predetermined distance, the test object 17 floats from the mounting table 16, and a gap is generated between the mounting table 16 and the test object 17. Next, the mounting table 16 is rotated around the rotation shaft 15 as shown in FIG. When the mounting table 16 is rotated in the direction of arrow A before the test object 17 falls at the natural fall acceleration g in the gap between the test object 17 and the mounting table 16 in FIG. It keeps parallel to the surface of the table 12 and falls toward the support table 12.

  The inventors made a prototype of the impact test apparatus 11 and dropped the test object 17 on the support base 12, but there were the following problems. FIG. 4 shows the state of the moment from FIG. 3 (b) to FIG. 3 (c), and FIG. 5 is a side view showing the dropping process of the specimen 17 from FIG. 3 (a) to FIG. is there. When the mounting table 16 is rotated around the rotation shaft 15 in the direction of arrow A in order to cause the test article 17 to fall naturally, a rotational moment about the axis of the rotation shaft 15 is applied to the mounting table 16. When the mounting table 16 is rotated around the rotation axis 15 in the direction of arrow A, a rotational moment M is generated at the position of the mounting table 16 corresponding to the side surface 171 of the test object 17, and it corresponds to the side surface 172 of the test object 17. A rotational moment m is generated at the place of the mounting table 16. As is well known, the magnitude of the rotational moment varies depending on the distance from the axis of the rotary shaft 15 and has a relationship of M> m.

  On the side surface 171 to which the rotational moment M is applied, ambient air enters the interface between the mounting table 16 and the test object 17 as a turbulent flow, and the reaction force W corresponding to the rotational moment M is caused by this turbulent flow. 17 is added to the side surface 171. Similarly, a reaction force w is applied to the side surface 172 of the test object 17 in accordance with the rotational moment m. Since M> m as described above, the reaction force W> w is established, and a non-uniform force acts on the side surfaces 171 and 172 of the specimen 17 that is separated from the mounting table 16 and naturally falls.

  By applying this non-uniform force, as shown in FIG. 5, the mounting table 16 and the test object 17 are applied to the side surface 171 of the test object 17 from FIG. Since the force W is larger than the force w applied to the side surface 172, the test object 17 is rotated from FIG. For this rotation, the mass of the test object 17, the adhesive force between the foot rubber and the mounting table 16 when the test object 17 is provided with, for example, a foot rubber, the area where the mounting table 16 and the test object 17 face each other, and Although various factors such as the fall distance are related, the rotation component is generated in the fall process.

  Thus, with the technology devised by the impact test apparatus 11, the surface of the test object 17 facing the mounting table 16 cannot be accurately dropped with good reproducibility on the surface of the support table 12, and the drop distance can be reduced. When changed, the posture of the test object 17 at the time of the collision changed, for example, the collision in the state of FIG. 5B or the collision in the state of FIG. However, if the gap distance between the mounting table 16 and the test object 17 is long, even if the rotational moments M and m are generated by the rotation operation of the mounting table 16, the reaction force W and w are not generated on the test object 17. That is possible in principle. However, there is a limit in moving the height adjusting unit 14 and the mounting table 16 with an acceleration G larger than the above-described natural fall acceleration g, and as a practical matter, the influence caused by the generation of the reaction forces W and w is suppressed. I couldn't. Therefore, even if the impact test apparatus 11 is used, a quantitative relationship between the drop distance and the impact of the drop impact cannot be obtained.

  It is an object of the present invention to provide a drop test apparatus that suppresses problems caused by rotation of a test object in the fall process.

  The drop test apparatus of the present invention that solves the above problems includes a mounting member that includes a maintenance member that maintains the object to be measured at a predetermined angle, an impact member that imparts an impact to the object to be measured, and the impact member And a holding member that is held at the relative position, and a pivot shaft that rotates the mounting member while being held at a desired relative position by the holding member. Prepare.

  With the above-described configuration, even when the drop height is changed, the drop posture in which the test object falls can be kept constant, and high reproducibility and reliability of the measurement result in the impact test can be obtained.

  Next, specific contents of the drop test apparatus of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view of an essential part for explaining the configuration of an embodiment of a drop test apparatus according to the present invention. The drop test apparatus 1 is engaged with a support 3 fixed to a support base 2, a support 3 and a predetermined height. A height adjusting unit 4 that maintains the height, a mounting table 6 that is pivotally supported by the rotating shaft 5 with respect to the height adjusting unit 4 and on which the test object 7 is mounted, and the rotating shaft 5 and the mounting table. 6 and an angle adjustment unit 8 that engages with 6. As the angle adjusting unit 8, for example, a plurality of types of wedge-shaped jigs having a plurality of inclination angles, and screw fastening for fixing two plate-like members to a predetermined angle by screwing with a support shaft pivotally supported. A jig independent of the mounting table 6 such as a jig for fixing the jig at a predetermined angle by exchanging a pin and a support shaft for pivotally supporting the two plate members. For example, a ring having a through hole into which the pin is loosely inserted and a height adjusting portion formed integrally with the mounting table 6 and a through hole into which the rotary shaft 5 is loosely inserted and the pin are fitted. A structure in which a pin is inserted into and removed from a bearing having a mating hole and fixed at a predetermined angle, and is integrally formed with a mounting portion 6 and a bearing portion that is formed integrally with the height adjusting portion 4 and is freely inserted into the rotating shaft 5. A structure that is fixed at a predetermined angle by screwing a ring to be fitted to the bearing portion with a screw, etc. Either a structure for fixing the engagement portion of the mounting 置第 6 and height adjusting unit 4 can be employed.

  A stainless steel SUS304 is used as the mounting table 6 of the drop tester 1 shown in FIG. 1, and a mass is obtained by hollowing out an acrylonitrile-butadiene-styrene resin (hereinafter referred to as ABS resin) block having a width of 300 mm, a depth of 250 mm, and a height of 40 mm. 1 kg and 3 kg are used as the test object 7, the drop speed is 500 mm, and the rotation speed of the mounting table 6 in the direction of arrow A (see FIG. 4) is farthest from the rotation shaft 5 of the test object 7. A drop test was performed at a rotation speed of 2.5 m / sec (about 10 G in terms of acceleration) at the tip of the mounting table 6. Further, the test object 7 on the mounting table 6 was mounted on the same position of the mounting table 6 with the width direction of the test object 7 parallel to the axial direction of the rotation shaft 5. In addition, 1 kg of the internal mass of the test object 7 is called the test object a, and 3 kg is called the test object b.

  First, the mounting table 6 and the support table 2 were made parallel, and the angle at which the test object 7 contacted the support table 2 was observed with a photograph. As a result of 10 drop tests, both the test objects a and b have the tendency shown in FIG. 5B. The inclination of the test object a is 7.34 ° with respect to the surface of the support base 2, and the test object b is 8. It was tilted by 08 °. This is due to the influence of the reaction force described above. Based on this result, the angle adjusting unit 8 shown in FIG. 1 sets the initial inclination angle between the test object a and the support base 2 to 7.34 °, and the initial inclination angle between the test object b and the support base 2 is set. The drop test was performed 10 times in the same manner at 8.08 °. As a result, the drop angle of the specimens a and b with respect to the support base 2 could be controlled to 0 °.

  In the test described above, the interface between the test specimens a and b and the mounting table 6 is a case where the ABS resin and SUS304 are in direct surface contact. However, the test specimen 7 such as an electronic device to be actually tested is tested. In most cases, the object 7 is provided with a foot rubber or the like to reduce the impact resistance. Further, the rubber hardness of the foot rubber and the contact area of the foot rubber with the mounting table 6 are also changed according to the mass of the test object 7. Furthermore, when the test object 7 is packed, it is necessary to consider the influence of the packing material. As described above, it is assumed that the test object 7 having the foot rubber, the packing material, and the like has different tendencies because the frictional force with the mounting table 6 is generated. Therefore, prior to the rotation of the mounting table 6 around the rotation shaft 5, the mounting table 6 is rotated after 600 msec while applying an initial speed of, for example, 1 m / sec. It is possible to perform a drop test with excellent reproducibility. In the above drop test, the drop distance is set to 500 mm. However, when the drop distance changes, it is naturally necessary to set the initial angle according to the drop distance, and it is adjusted by the angle adjustment unit 8 in the same manner as described above. By doing so, a drop impact can be given to the desired location of the test specimen 7 in the entire test specimen 7.

  The drop test apparatus of the present invention can be applied to drop tests in a wide range of fields, from small and light electronic devices such as mobile phones to packed items packed with large items such as refrigerators.

The principal part side view of one Embodiment of the drop test apparatus which concerns on this invention Side view of main part of impact test device according to conventional configuration (A) is a main part side view for explaining an initial state of the impact test apparatus, (b) is a main part side view for explaining a state immediately after dropping, and (c) is a main part side view for explaining a state during dropping. Side view of the main part explaining details of the state immediately after dropping in the impact test device (A) is a side view for explaining the state immediately after dropping in the impact test apparatus, (b) is a side view for explaining the state of the initial dropping process, and (c) is a side view for explaining the state of the dropping process.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drop test apparatus 2 Support stand 3 Support | pillar 4 Height adjustment part 5 Rotating shaft 6 Mounting stand 7 Test object 8 Angle adjustment part

Claims (1)

A mounting member having a maintaining member for maintaining the object to be measured at a predetermined angle;
An impact member for applying an impact to the object to be measured;
While changing the relative position of the impact member and the mounting member, a holding member that holds the relative position,
A drop test apparatus comprising: a pivot shaft that pivots the mounting member while being held at a desired relative position by the holding member.

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