Test device

Abstract

To provide a test device capable of further suppressing variation with respect to a target value compared with a conventional manner.SOLUTION: A test device 1 causes a load to actuate on a test piece W. The test device 1 includes: a servo motor 2 as a motor; a screw shaft 3 connected to a rotation shaft of the servo motor 2; a lifting rod 4 integrated with a nut to be slidably moved by the rotation of the screw shaft 3; a load rod 5 attached to the test piece W so as to cause the load to actuate; and an elastic connection mechanism 6 placed between the lifting rod 4 and the load rod 5.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a testing device for applying a load to a test piece. [Background technology]

[0002] Conventionally, in test equipment for evaluating material properties such as crack growth characteristics, the tensile force applied to the test piece is kept constant or increased or decreased using, for example, a motor and a ball screw. The applied tensile force is controlled by the rotation direction and number of rotations of the motor (see Figure 11).

[0003] In such a test device, it is generally considered that the tensile force loading structure from the motor to the test piece should be made of a material with high rigidity so that the load (tensile force) is sufficiently transmitted to the test piece. For example, in Patent Document 1, in order to transmit the load according to the load waveform with high accuracy at high frequency, the frame 50, the rods 56 and 60 attached to the frame 50, and the hydraulic actuator 54 are all fixed by surface contact of metal members. The reason for this is that if a low-rigidity member such as resin is present, the load transmission is not smooth, and if a protrusion or an inclined contact surface is present in the load transmission path, it may cause the axis to shift (eccentricity) or hinder the transmission of amplitude (see paragraph 0047 of Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-198783 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the load (tensile force) applied is specifically controlled by rotating the motor to reduce the load so that it approaches the target value if the current value of the load is greater than the target value, and by repeatedly increasing the load if the current value is smaller. Therefore, in a conventional tensile force loading structure with high rigidity, the movement of the motor is directly reflected in the fluctuation of the tensile force, resulting in large variations from the target value.

[0006] SUMMARY OF THE PRESENT EMBODIMENTS An object of the present invention is to provide a test apparatus that can reduce the variation from the target value more than ever before. [Means for solving the problem]

[0007] In order to achieve the above object, the test apparatus of the present invention is a test apparatus that applies a load to a test piece, and includes a motor, a screw shaft connected to a rotation shaft of the motor, a lifting rod integrated with a nut that slides by rotation of the screw shaft, a load rod attached to the test piece and applies a load, and an elastic connecting mechanism installed between the lifting rod and the load rod. It is equipped with: Effect of the Invention

[0008] In this way, since the testing apparatus of the present invention is equipped with a motor, a screw shaft, a lifting rod, a load rod, and an elastic connecting mechanism installed between the lifting rod and the load rod, the movement of the motor is not transmitted directly to the load rod but is transmitted in a damped manner, making it possible to reduce the variation in the applied load from the target value more than in the past. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram of the overall structure of a testing device according to the present invention. [Diagram 2] FIG. 2 is a cross-sectional view illustrating the structure of an elastic connecting mechanism of the test device (applying a tensile load) of Example 1. [Diagram 3]1A and 1B are diagrams illustrating the movement of the elastic coupling mechanism of the first embodiment, where (a) shows the movement when the load increases, and (b) shows the movement when the load decreases. [Figure 4] A cross-sectional view listing variations in the number and orientation of disc springs in an elastic connection mechanism. (a) is a different pattern of series combination, (b) is parallel stacking, and (c) is a combination of series and parallel. [Diagram 5] 13A and 13B are cross-sectional views illustrating the structure of an elastic connecting mechanism according to another embodiment. [Figure 6] FIG. 2 is a block diagram illustrating the configuration of a control system of the test apparatus. [Figure 7] 4 is a graph illustrating the operation of the elastic connecting mechanism. [Figure 8] 1 is a graph showing load control data using a conventional testing machine and a new testing machine (test device). [Figure 9] FIG. 11 is a cross-sectional view illustrating the structure of an elastic connecting mechanism of a test device (applying a compressive load) in Example 2. [Figure 10] FIG. 11 is a cross-sectional view illustrating the structure of an elastic connecting mechanism of a test device (applying a tensile load / compressive load) of Example 3. [Figure 11] FIG. 1 is an explanatory diagram of the overall structure of a conventional testing device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the components described in the following embodiments are merely examples, and are not intended to limit the technical scope of the present invention. EXAMPLES

[0011] (composition) First, the overall structure of the test apparatus 1 of this embodiment will be described with reference to FIG. 1. The test apparatus 1 is a material testing apparatus for evaluating material properties such as crack growth properties. The crack growth properties can be evaluated by a stress corrosion cracking (SCC) test described in JISH8711:2000. In the stress corrosion cracking test, a constant load test is generally performed, and the test apparatus 1 has a structure that can be used for this constant load test. In addition, in recent years, there has been a demand for stress corrosion cracking tests under conditions that are closer to the actual environment. For example, since spherical or cylindrical structures are used under high temperature and high pressure, the material properties of such structures under the environmental conditions are evaluated.

[0012] The stress generated in a metal material that has been bent into a spherical or cylindrical shape changes continuously from tensile to compressive, or from compressive to tensile, along the thickness direction. As a crack that has started from the tensile side progresses in the thickness direction, the tensile force decreases continuously. When evaluating the progress of such cracks from initiation to fracture, a load reduction test is more suitable than a constant load test, and if the load reduction is smooth, test results can be obtained under conditions close to the stress distribution of the actual metal material. The test device 1 can be suitably used for such load reduction tests.

[0013] In the test apparatus 1 of this embodiment, as shown in Fig. 1, a test specimen W is placed in an autoclave 11 installed on a highly rigid stand 10, and a tensile load is applied to the test specimen W. Specifically, the test apparatus 1 includes an (electric) servo motor 2 as a motor, a screw shaft 3 connected to the rotating shaft of the servo motor 2, a lifting rod 4 integrated with a nut that slides up and down by the rotation of the screw shaft 3, a load rod 5 attached to the test specimen W to apply a load, and an elastic connecting mechanism 6 installed between the lifting rod 4 and the load rod 5, and the whole is supported by the stand 10. If a high temperature and high pressure environment is not required, the autoclave 11 does not need to be installed.

[0014] Of these, the servo motor 2, which serves as a motor, is supplied with power from a servo amplifier (83) to control the direction and speed of rotation, as described later with reference to Fig. 6. A male screw groove (not shown) is threaded on the outer peripheral surface of the upper part of the screw shaft 3, which is connected directly to the servo motor 2 or indirectly via a gear, and is adapted to screw into a nut (not shown) having a female screw groove threaded on its inner peripheral surface that is integral with the lift rod 4. Therefore, when the servo motor 2 rotates, the lift rod 4 moves up and down (relative to the stand 10) in conjunction with the rotation.

[0015] Meanwhile, a test piece W is attached to the upper end of the load rod 5. More specifically, chucks (not shown) for gripping the upper and lower sides of the test piece W are provided on the flat bed of the stand 10. The upper end of the load rod 5 is connected to the lower chuck (not shown). A digital load meter 81 is connected to the load rod 5. As the load meter 81, for example, a load cell can be used.

[0016] In the test device 1 of this embodiment, an elastic connecting mechanism 6 for mitigating abrupt changes in the applied load is installed between the lift rod 4 and the load rod 5. That is, the elastic connecting mechanism 6 reduces the apparent rigidity of this load applying mechanism in the vertical direction (the direction in which the load is applied), thereby mitigating the direct reflection of the rotation of the servo motor 2 on the applied load.

[0017] As shown in FIG. 2, this elastic connecting mechanism 6 is composed of a lower flange portion 41 connected to the upper end of the lifting rod 4 opposite the screw shaft 3, an upper flange portion 51 connected to the lower end of the load rod 5 opposite the test piece W, a case portion 60 that houses the lower flange portion 41 and the upper flange portion 51 so that they can move vertically within their height range, two disc springs 71A, 71B installed between the lower flange portion 41 and the bottom plate 602 of the case portion 60 below it, and two disc springs 71A, 71B installed between the upper flange portion 51 and the top plate 601 of the case portion 60 above it.

[0018] The lower flange portion 41 and the upper flange portion 51 are formed, for example, in the form of plates of the same shape, and can be configured to be attached / detached to the upper end of the lifting rod 4 and the lower end of the load rod 5, respectively, using bolts or the like.

[0019] Case part 60 houses upper flange part 51, lower flange part 41 and disc springs 71A, 71B, 71A, and 71B. That is, a hole 601a is formed in a top plate 601 of case part 60, through which load rod 5 is inserted, and a hole 602a is formed in a bottom plate 602, through which lift rod 4 is inserted.

[0020] 2, the disc springs 71A and 71B are of a so-called inner diameter guide type, with the lift rod 4 and the load rod 5 serving as guide rods, but are not limited to this and may be of an outer diameter guide type. Also, for the sake of convenience in explanation, the case part 60 is depicted in FIG. 2 as a housing with a closed internal space, but is not limited to this and may be any type as long as it can form a space with a limited (fixed) height in the load application direction, and the side surface can be open.

[0021] The disc spring 71A (71B) is formed in a truncated cone shape with circular openings at the top and bottom. The disc spring 71A (71B) is designed to resist the movement of the truncated cone shape being compressed in the height direction with its elastic force. The four disc springs 71A, 71B, 71A, 71B (two on the top and two on the bottom) are installed so that the "deflection direction" is parallel to the central axis of the screw shaft 3, the central axis of the lift rod 4, and the central axis of the load rod 5. The disc springs 71A (71B) can be "steel disc springs used individually or in combination of multiple sheets" as specified in JIS B2706.

[0022] 2, between the lower flange 41 and the bottom plate 602 of the case part 60, the disc springs 71B opening downward toward the bottom plate 602 and the disc springs 71A opening upward toward the lower flange 41 are arranged in an X-shape with their orientations staggered. Therefore, when the lower flange 41 tries to move downward (toward the bottom plate 602) relative to the case part 60, the disc springs 71A and 71B resist by pushing back the movement with their elastic force. Alternatively, when the case part 60 tries to move upward relative to the lower flange 41, the disc springs 71A and 71B resist.

[0023] 2, between upper flange 51 and top plate 601 of case part 60, disc spring 71A opening upward toward top plate 601 and disc spring 71B opening downward toward upper flange 51 are arranged in an X-shape with their orientations staggered. Therefore, when upper flange 51 attempts to move upward (toward top plate 601) relative to case part 60, disc springs 71A and 71B resist by pushing back with their elastic force. Alternatively, when case part 60 attempts to move downward relative to upper flange 51, disc springs 71A and 71B resist.

[0024] Here, in "7.2 Load characteristics when combined" of JIS B2706, the state in which the opening directions of the disc springs 71A and 71B as described above are different is defined as "series," and the state in which the opening directions of the disc springs 71A and 71B are the same and overlap each other is defined as "parallel."

[0025] Therefore, the elastic connecting mechanism 6 operates as shown in Figures 3(a) and (b). That is, when the downward load (tensile load) increases from the initial state, the disc springs 71A, 71B, 71A, and 71B contract in the load direction as shown in Figure 3(a). Then, although the tensile load acting on the lift rod 4 and the tensile load acting on the load rod 5 will ultimately be the same value, in a transitional state, the load acts leveled out for the time required for the disc springs 71A and 71B to contract.

[0026] On the other hand, when the downward load (tensile load) decreases from the initial state, the disc springs 71A, 71B, 71A, and 71B stretch in the load direction as shown in Fig. 3(b). Eventually, the tensile load acting on the lift rod 4 and the tensile load acting on the load rod 5 will be the same value, but in a transitional state, the load acts in a leveled manner for the time it takes for the disc springs 71A and 71B to stretch.

[0027] 4(a) to 4(c), variations in the configuration of the elastic connecting mechanism 6, particularly variations in the combination of the orientation and number of disc springs 71A, 71B, 71A, 71B, will be briefly described. The disc springs 71A, 71B can be arranged in a pattern in which both upper and lower sets are combined in series as shown in Fig. 4(a) (the positions of disc springs 71A and 71B are switched in comparison with Fig. 2), in a pattern in which both upper and lower sets are stacked in parallel as shown in Fig. 4(b), or in a pattern in which the upper set is in parallel and the lower set is in series as shown in Fig. 4(c).

[0028] Of course, other combinations are also possible. Furthermore, the total number of the disc springs 71A and 71B is not limited to four, and the number and orientation can be changed depending on the load applied to the test piece W. For example, the total number of the disc springs 71A and 71B may be three or less, or five or more.

[0029] Next, the configuration of another embodiment of the elastic connection mechanism 6' will be described with reference to Fig. 5. Unlike the above-mentioned embodiments and variations, this other embodiment of the elastic connection mechanism 6' has disc springs 71A and 71B installed only on the lift rod 4 side. This elastic connection mechanism 6' is composed of a lower flange part 41 connected to the lift rod 4, a case part 60 connected integrally with the load rod 5 and movably housing the lower flange part 41, and disc springs 71A and 71B arranged between the lower flange part 41 and a bottom plate 602 of the case part 60.

[0030] For this reason, the elastic connecting mechanism 6' of the alternative embodiment resists tensile loads by the elastic force of the disc springs 71A and 71B, but is designed so that the elastic force of the disc springs 71A and 71B does not act on compressive loads. Therefore, compared to the elastic connecting mechanism 6 of the embodiment, the elastic connecting mechanism 6' can transmit loads with reduced change over time using a simpler structure.

[0031] (Control system configuration) Next, the configuration of the control system of the test device 1 will be described with reference to the block diagram of Fig. 6. The control system of the test device 1 includes an input system including a digital load meter 81 connected to the load rod 5, a sequencer 82 serving as a controller for calculating a command signal based on a digital load signal from the load meter 81, and an output system including a servo amplifier 83 receiving the command signal from the sequencer 82 and supplying power, and a servo motor 2 serving as a motor and rotating with power supplied from the servo amplifier 83.

[0032] Therefore, the load signal measured by the load meter 81 is transmitted as a digital signal to the sequencer 82. The sequencer 82 calculates the power to be supplied to the servo motor 2 and sends a command signal to the servo amplifier 83. Finally, the servo amplifier 83 supplies the commanded power to the servo motor 2 to rotate the ball screw and increase or decrease the applied load. In this way, the applied load is feedback-controlled.

[0033] (action) Next, the operation of the testing device 1 of this embodiment will be described with reference to the graph in Fig. 7. Here, an example of reducing the applied load from point A (time T1, load F1) to point B (time T2, load F2) will be described. First, in the conventional example shown by the dotted line, when reducing the applied load from point A to point B, the load is reduced all at once. In this case, the load is reduced from F1 to F2 in an extremely short time at time T1, resulting in a large change in load over time.

[0034] On the other hand, in the test apparatus 1 of this embodiment shown by the solid line, the applied load is divided into several steps from point A to point B and gradually reduced. That is, for example, the load is gradually reduced from F1 to F2 over a period of time in eight steps from time T1 to T2, so the change in load over time is small. This is mainly due to the fact that the load signal can now be obtained as a digital signal, which means that high-resolution feedback control is now possible.

[0035] Further, when each step in FIG. 7 is considered, the load reduction change for each step is mitigated by decreasing the apparent stiffness of the load application mechanism in the vertical direction. In other words, if the elastic connection mechanism 6 is not provided, the load reduction change at each step is not mitigated even if the number of divisions of the steps is increased, and the load reduction change at each step is steep (almost parallel to the vertical axis) as in the conventional example shown by the dotted line in the graph. In contrast, if the elastic connection mechanism 6 is provided, the load change at each step is mitigated, and the change is gentle (inclined to the vertical axis) on the graph. The example shown in FIG. 7 is an example of a load reduction change, but the present invention is not limited to this, and the provision of the elastic connection mechanism 6 is also effective for a constant load. When controlling to a constant load, the load is changed to decrease or increase in order to reduce the difference with the target load. If the elastic connection mechanism 6 is provided, the load change at this time is suppressed from being steep, and the change is gentle as in each step described above.

[0036] In fact, data from the conventional testing machine and the new testing machine (Test Apparatus 1) of this embodiment are shown side by side in Fig. 8 for easy comparison. In the figure, the conventional testing machine is on the left and the new testing machine (Test Apparatus 1) is on the right. The vertical axis indicates the load and the horizontal axis indicates the elapsed time. As is clear from the figure, when the Test Apparatus 1 of this embodiment is used, the load changes are smoother and the load fluctuation range (corresponding to the dispersion) is about 1 / 4 compared to the conventional case. When analyzed in more detail, it can be seen that while the graph of the conventional testing machine is composed only of vertical and horizontal parts, the graph of the Test Apparatus 1 of this embodiment is a relatively smooth broken line.

[0037] (effect) Next, the effects achieved by the test device 1 of this embodiment will be listed and explained.

[0038] (1) As described above, the test apparatus 1 of this embodiment applies a load to the test piece W, and includes a servo motor 2 as a motor, a screw shaft 3 connected to the rotating shaft of the servo motor 2, a lifting rod 4 integrated with a nut that slides by the rotation of the screw shaft 3, a load rod 5 attached to the test piece W to apply a load, and an elastic connecting mechanism 6 installed between the lifting rod 4 and the load rod 5. Since the test apparatus 1 has such a configuration, it is a test apparatus 1 that can reduce the variation of the applied load from the target value compared to the conventional one. That is, in the conventional load application structure with high rigidity, the movement of the motor is directly reflected in the fluctuation of the tensile force, which increases the variation from the target value, but in the test apparatus 1 of this embodiment, the rigidity of the load application structure is lower than that of the conventional one by interposing the elastic connecting mechanism 6, and therefore the movement of the servo motor 2 is mitigated and transmitted to the load rod 5 side.

[0039] Specifically, if the straight line connecting points A and B in FIG. 7 (shown as a dashed line in FIG. 7) is taken as the "target value" of the applied load, the difference between that straight line (dashed line) and the dotted line is the variation in the conventional technology, and the difference between the straight line (dashed line) and the solid line is the variation in this embodiment, so it can be said that the variation in this embodiment is smaller than that of the conventional technology.

[0040] (2) Furthermore, the elastic connecting mechanism 6 has one or more disc springs 71A (71B), and the deflection direction of the one or more disc springs 71A (71B) is parallel to the central axis of the screw shaft 3 and the central axis of the lift rod 4, so that the performance of the disc springs 71A (71B) can be efficiently exhibited to transmit the load. Furthermore, the elastic connecting mechanism 6 can be configured using known performance when the disc springs are arranged in series or in parallel.

[0041] (3) Furthermore, one or more disc springs 71A (71B) are configured so that the number and orientation can be changed according to the load applied to the test piece W, so that an optimal elastic force can be applied by using the elastic connecting mechanism 6 in response to various loads. For example, this can be realized by making the case part 60 disassembleable and the upper flange part 51 and the lower flange part 41 detachable.

[0042] (4) The elastic connecting mechanism 6 further has a lower flange portion 41 connected to the end of the lifting rod 4 opposite the screw shaft 3, an upper flange portion 51 connected to the end of the load rod 5 opposite the test piece W, and a case portion 60 that movably accommodates the lower flange portion 41 and the upper flange portion 51, and one or more disc springs 71A, 71B, 71A, 71B are arranged at least in one of the following locations: between the lower flange portion 41 and the bottom plate 602 of the case portion 60 below it, between the upper flange portion 51 and the top plate 601 of the case portion 60 above it, or between the lower flange portion 41 and the upper flange portion 51. With this configuration, the load is transmitted in the order of the lifting rod 4 and lower flange 41, the lower disc springs 71A, 71B, the case portion 60, the upper disc springs 71A, 71B, the upper flange 51, and the load rod 5, so that the load can be transmitted between the lifting rod 4 and the load rod 5 while mitigating changes over time in the load.

[0043] (5) Furthermore, the elastic connection mechanism 6' further includes a lower flange 41 connected to the end of the lift rod 4 opposite to the screw shaft 3, and a case part 60 that is integrally connected to the load rod 5 and movably houses the lower flange 41, and one or more disc springs 71A, 71B are disposed at least in one of the following locations: between the lower flange 41 and the bottom plate 602 of the case part 60 below it, or between the lower flange 41 and the top plate 601 of the case part 60 above it. With this configuration, the load is transmitted in the order of the lift rod 4 and the lower flange 41, the lower disc springs 71A, 71B, the case part 60, and the load rod 5, so that the load can be transmitted between the lift rod 4 and the load rod 5 while mitigating changes over time.

[0044] (6) Furthermore, when a tensile load is applied to the test piece W, one or more disc springs 71A, 71B of the elastic connecting mechanism 6 are arranged so as to resist the movement of the lift rod 4 and the load rod 5 in the direction away from each other. With this configuration, the elastic force of the disc springs 71A, 71B is used to counter the tensile load, thereby suppressing the change in the applied load over time. EXAMPLES

[0045] Hereinafter, an elastic connection mechanism 6A in which a compressive force is applied, which is different from that in the first embodiment, will be described with reference to Fig. 9. Note that the same reference numerals will be used to denote the same or equivalent parts as those in the first embodiment.

[0046] First, the configuration will be described. When a compressive load is applied to a test piece W using the test device 1 of this embodiment, one or more disc springs 71A, 71A of the elastic connecting mechanism 6A are arranged so as to resist the movement of the lift rod 4 and the load rod 5 in the direction toward each other, as shown in Fig. 9.

[0047] Specifically, the parallel disc springs 71A, 71A are disposed between the opposing upper flange 51 and lower flange 41. That is, the disc springs 71A, 71A are not disposed between the upper flange 51 and the top plate 601 and between the lower flange 41 and the bottom plate 602. On the other hand, for example, as in another embodiment of the first embodiment, when the load rod 5 is integrated with the case part 60, the disc springs 71A, 71A can be disposed between the lower flange 41 and the top plate 601.

[0048] Next, the operation of the elastic connection mechanism 6A of the test device 1 of this embodiment will be described. When a compressive load is applied, the disc springs 71A, 71A contract in the load direction. Eventually, the compressive load acting on the lift rod 4 and the compressive load acting on the load rod 5 will be the same value, but in a transitional state, the load is leveled out and applied for the time it takes for the disc springs 71A, 71A to contract.

[0049] More specifically, the load is transmitted in the order of the lifting rod 4 and the lower flange 41, the disc springs 71A, 71A, the upper flange 51, and the load rod 5, so that the load can be transmitted between the lifting rod 4 and the load rod 5 while mitigating changes in the load over time.

[0050] As described above, when a compressive load is applied to the test piece W, one or more disc springs 71A, 71A of the elastic connecting mechanism 6A are arranged to resist the movement of the lift rod 4 and the load rod 5 in the direction toward each other. With this configuration, the elastic force of the disc springs 71A, 71A is used to counter the compressive load, thereby suppressing the change in the applied load over time.

[0051] Other configurations and effects are substantially the same as those in the first embodiment, and therefore description thereof will be omitted. EXAMPLES

[0052] 10, an elastic connecting mechanism 6B in which both tensile and compressive forces are applied will be described below, unlike in the first and second embodiments. Note that the same reference numerals will be used to describe the same or equivalent parts as those described in the first and second embodiments.

[0053] First, the configuration will be described. When both tensile and compressive forces are applied to the test piece W using the test device 1 of this embodiment, one or more disc springs 71A, 71B of the elastic connecting mechanism 6B are arranged so as to resist the movement of the lift rod 4 and the load rod 5 in the directions away from each other, and are arranged so as to resist the movement of the lift rod 4 and the load rod 5 in the directions toward each other, as shown in Fig. 9.

[0054] Specifically, the disc springs 71A, 71B are composed of two disc springs 71A, 71B installed between the upper flange 51 and the top plate 601 of the case part 60 above it, a disc spring 71A (71B) arranged between the upper flange 51 and the lower flange 41 facing each other, and two disc springs 71A, 71B installed between the lower flange 41 and the bottom plate 602 of the case part 60 below it. On the other hand, for example, as in another form of the first embodiment, when the load rod 5 is integrated with the case part 60, the disc springs 71A, 71B can be arranged between the lower flange 41 and the bottom plate 602 and between the lower flange 41 and the top plate 601.

[0055] Next, the operation of the elastic connection mechanism 6B will be described. When a compressive load is applied, the lift rod 4 moves upward, and the disc spring 71A placed on the lower flange 41 also moves upward. When the disc spring 71A comes into contact with the upper flange 51, the disc spring 71A between the lower flange 41 and the upper flange 51 and the disc springs 71B and 71A between the upper flange 51 and the top plate 601 contract in the load direction. Eventually, the compressive load acting on the lift rod 4 and the compressive load acting on the load rod 5 will be the same value, but in a transitional state, the load is leveled out and acts for the time required for the disc springs 71A, 71B, and 71A to contract.

[0056] When a tensile load acts, the lift rod 4 moves downward, and the disc springs 71B, 71A between the lower flange 41 and the bottom plate 602 contract in the load direction. Then, the case part 60 also moves downward, and the disc springs 71A, 71B between the top plate 601 and the upper flange 51 contract. Then, the load rod 5 receives a downward force via the upper flange 51 and moves downward. Then, although the tensile load acting on the lift rod 4 and the tensile load acting on the load rod 5 ultimately have the same value, in a transitional state, the load acts leveled out for the time required for the disc springs 71A, 71B, 71A to contract.

[0057] As described above, when a compressive load and a tensile load are applied to the test piece W, one or more disc springs 71B, 71A, 71A, 71B, and 71A of the elastic connecting mechanism 6B are arranged so as to resist movement of the lift rod 4 and the load rod 5 in directions toward each other, and also so as to resist movement of the lift rod 4 and the load rod 5 in directions away from each other. With this configuration, the elastic forces of the disc springs 71B, 71A, 71A, 71B, and 71A are used to counter both the compressive load and the tensile load, thereby suppressing the change in the applied load over time.

[0058] Other configurations and effects are substantially the same as those in the first embodiment, and therefore description thereof will be omitted.

[0059] Although an embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes that do not deviate from the gist of the present invention are included in the present invention.

[0060] For example, in the embodiment, the configuration of the disc spring 71A (71B) is enumerated, but the present invention is not limited to this, and it is of course possible to adopt a configuration of the disc spring 71A (71B) other than that of the embodiment. [Explanation of symbols]

[0061] W test piece 1 Test equipment 2. Servo motor (motor) 3 Screw shaft 4 Lifting rod 10 Mounting stand 11 Autoclave 41 Lower Tsuba 5 Load Rod 51 Upper flange 6 Elastic connection mechanism (tension) 6A Elastic coupling mechanism (compression) 6B Elastic connection mechanism (tension / compression) 60 Case part 601 Top plate 602 Bottom plate 71 Disc spring 71A Disc spring (opens upwards) 71B Disc springs (open downwards) 81 Load cell 82 Sequencer 83 Servo Amplifier

Claims

1. A test device that applies a load to a test piece, A motor; A screw shaft connected to a rotating shaft of the motor; A lifting rod is integrated with a nut that slides by rotation of the screw shaft; A load rod attached to the test piece to apply a load; an elastic coupling mechanism installed between the lift rod and the load rod; A test apparatus comprising:

2. The elastic coupling mechanism includes one or more disc springs, 2. The testing device of claim 1, wherein the deflection direction of the one or more disc springs is parallel to a central axis of the screw shaft and a central axis of the lift rod.

3. 3. The testing device according to claim 2, wherein the one or more disc springs are configured so that the number and orientation of the disc springs are changeable according to a load applied to the test piece.

4. The elastic connecting mechanism further includes a lower flange portion connected to an end of the lift rod opposite to the screw shaft, an upper flange portion connected to an end of the load rod opposite to the test piece, and a case portion that movably houses the lower flange portion and the upper flange portion, 4. The testing device of claim 3, wherein one or more of the disc springs are arranged in at least one of the following locations: between the lower flange and the case portion below it, between the upper flange and the case portion above it, or between the lower flange and the upper flange.

5. The elastic coupling mechanism further includes a lower flange portion connected to an end of the lift rod opposite to the screw shaft, and a case portion connected to the load rod and movably housing the lower flange portion, 4. The testing device according to claim 3, wherein one or more of the disc springs are arranged at least in one of a position between the lower flange portion and the case portion below it, or a position between the lower flange portion and the case portion above it.

6. A testing apparatus as described in any one of claims 2 to 5, wherein when a tensile load is applied to the test piece, one or more of the disc springs of the elastic connecting mechanism are arranged to resist movement of the lift rod and the load rod away from each other.

7. A testing apparatus as described in any one of claims 2 to 5, wherein when a compressive load is applied to the test piece, one or more of the disc springs of the elastic connecting mechanism are arranged to resist movement of the lift rod and the load rod toward each other.

8. A testing apparatus as described in any one of claims 2 to 5, wherein when a tensile load and a compressive load are applied to a test piece, one or more of the disc springs of the elastic connecting mechanism are arranged to resist movement of the lift rod and the load rod away from each other, and are arranged to resist movement of the lift rod and the load rod toward each other.

9. The testing device according to any one of claims 2 to 5, comprising: a digital load meter connected to the load rod; a sequencer that calculates a command signal based on a digital load signal from the load meter; a servo amplifier that receives the command signal from the sequencer and supplies power; and a servo motor that rotates by receiving power from the servo amplifier as the motor.

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