JPH0459577B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a drop weight impact tester used to test the characteristics of parts at the same impact acceleration.

``Prior Art'' A falling weight impact tester that applies pulse-like impact to mechanical parts or electrical/electronic parts has conventionally been configured with a frame or bed that has a guide to support the sample stage when it falls. It consists of a sample stage and a cylinder or hoisting device that lifts the sample stage to a set height. It is an open-loop system that simply captures the impact acceleration as an electrical signal using an oscilloscope or the like using an acceleration detector attached to the sample stage, and there is no function to maintain impact acceleration with good reproducibility over a long period of time.

“Problems to be Solved by the Invention” The above-mentioned conventional drop weight impact tester is susceptible to changes in the characteristics of the pads attached to both the sample stand and the bed, as well as changes in the sliding parts between the sample stand and the bed. There is a problem in that the impact acceleration cannot be maintained constant over a long period of time due to changes in the coefficient of friction and the like. In other words, the impact acceleration of conventional drop weight impact testing machines gradually changes over long periods of operation, so they are not suitable as impact testing machines for manufacturing processes that apply the same impact acceleration to parts and inspect their properties. It wasn't.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a drop weight impact tester that can generate the same impact acceleration with good reproducibility over a long period of time.

"Means for Solving the Problem" In order to achieve the above object, the present invention provides an acceleration detector attached to a sample stage capable of free fall in order to detect actual impact acceleration, and correction amount calculation means for calculating a correction amount for the falling height of the sample stage from a deviation from the speed determined from the requested impact acceleration by calculating the speed from the acceleration;
There is provided a falling weight type impact tester characterized by having an automatic fall height correction mechanism that finely adjusts the free fall start position of the sample stage based on the output of the correction amount calculation means.

"Operation" According to the above-mentioned falling weight type impact tester, the correction amount calculation means calculates the correction amount for the falling height of the sample stage from the deviation between the speed calculated from the actual impact acceleration and the speed determined from the requested impact acceleration. Based on the calculation, the automatic fall height correction mechanism automatically finely adjusts the free fall start position of the sample stage.

"Embodiment" An embodiment of the present invention will be described with reference to FIGS. 1 to 5.

The sample stage 1 is arranged so as to be slidable in the vertical direction by means of a bearing 4 with respect to a guide post 3 which is erected and fixed on the upper surface of the bed 2. Further, a rod 5 is fixed to the lower surface of the sample stage 1 and moves up and down together with the sample stage 1.
It is well known that the combination of the upper part 6 and the lower part 7 having certain specific characteristics causes the parts 6, 7 to repel due to the requirement of obtaining impact acceleration. A roller 8 is provided at the lower end of the rod 5,
Stopper 10 that moves left and right by horizontal cylinder 9
This reduces the frictional resistance between the The horizontal cylinder 9 and stopper 10 are configured to move vertically together as a unit by a ball screw 11, and move up and down by a correction amount in accordance with the amount of rotation of the pulse motor 12.

The vertical cylinder 13 lifts the horizontal cylinder 9 and the stopper 10 to a fixed size, that is, to the theoretical drop height, and then lifts the sample stage 1 through the rod 5.
to the starting position of the fall.

The output signal of an acceleration detector 14 (not shown) fixed to the sample stage 1 is processed by an amplifier 15, a memory circuit 16, a computer 17, a pulse motor drive circuit 18, and a standard value input circuit 19 as shown in FIG. The output of the pulse motor drive circuit 18 is applied to the pulse motor 12.

The operation of the above-mentioned drop weight type impact tester will be explained below.

At the lowering end of the vertical cylinder 13, the horizontal cylinder 9 is advanced and the stopper 10 is moved below the roller 8. At this time, the pulse motor 12
is at the theoretical value of rotation amount set to obtain the required impact acceleration. Therefore, since the ball screw 11 sets the unit consisting of the combination of the horizontal cylinder 9 and the stopper 10 at the initial correction amount position, when the vertical cylinder 13 is raised to push up the horizontal cylinder 9 and the stopper 10, The sample stage 1 is lifted up via the rod 5 to the theoretical value of the fall height (fall start position).

After this, the horizontal cylinder 9 is moved back and the stopper 1 is
When the specimen 0 is pulled out laterally at high speed, the roller 8 loses its lower support and the specimen stage 1 begins to fall freely along the guide post 3 together with the rod 5. Then, the upper pad 6 fixed to the lower surface of the sample stage 1 collides with the lower pad 7 fixed to the upper surface of the bed 2, producing impact acceleration. On the other hand, the acceleration detector 14 attached to the sample stage 1 outputs a voltage corresponding to the detected impact acceleration, so this is amplified by the amplifier 15 and stored in the storage circuit 16 as the actually measured impact acceleration curve C.

Thereafter, move the unit, with the horizontal cylinder 9 and stopper 10 retracted, to the vertical cylinder 1.
3 to the lower end, the horizontal cylinder 9 is advanced, and the stopper 10 is placed on the rod 5 so as to face below the roller 8, and is kept on standby until the start of the next cycle.

The measured impact acceleration curve C stored in the storage circuit 16 is input to the computer 17 and analyzed according to a predetermined program. Specifically, as shown in FIG. 4, the measured impact acceleration curve C is regarded as a haversine curve, and the points where the curve C intersects the acceleration α=0 are defined as A and B. The time t between points A and B is the period T, and the maximum acceleration value is the maximum acceleration αm
It is defined as Curve C is integrated between points A and B, and the resulting value is taken as velocity V. Of these three elements (T, αm, V) that determine the curve C, the velocity V
is compared with the speed determined from the required impact acceleration curve set by the standard value input circuit 19, and the deviation thereof is calculated. Then, based on the deviation, the fall height correction value h is converted into the rotation angle of the pulse motor 12, and the pulse motor drive circuit 18
A command is given to the pulse motor 12 via the pulse motor 12. Since the pulse motor 12 rotates to a rotation angle corresponding to the correction amount h, the unit of the horizontal cylinder 9 and stopper 10 combined with the ball screw 11 corrects the fall height with respect to the theoretical fall height _H0 . It rises or falls by the amount h to reach the appropriate fall height (fall start position) H.
is obtained (see Figure 3).

Further, if a re-fall prevention device 20 is added to the underside of the bed 2 to catch the rod 5 during the first jump and eliminate the impact caused by the re-fall, it will be even more effective and the cycle time can be shortened.

As another embodiment, the drop height correction mechanism of the drop weight type impact tester may be a height setting mechanism including another rotation mechanism, a screw, or the like.

Furthermore, the three elements that determine the impact acceleration curve C, the maximum acceleration αm, the velocity V, and the period T, are
Each of them can be used alone or in any combination as a parameter for calculating the fall height correction amount h.

"Effects of the Invention" The drop weight impact tester of the present invention has the above configuration, and the correction amount calculating means calculates the difference between the speed calculated from the actual impact acceleration and the speed determined from the required impact acceleration for the sample. The fall height automatic correction mechanism calculates the correction amount for the fall height of the platform, and based on that, the fall height automatic correction mechanism
The free fall start position of the sample table, which directly contributes to the magnitude of impact acceleration, is automatically fine-tuned, making it possible to generate the same impact acceleration over a long period of time with good reproducibility. Since it is limited to the falling height, the structure of the operation sequence and the structure of the automatic correction mechanism are simplified, and there are excellent effects such as the effectiveness of use as fully automatic production equipment is increased.

[Brief explanation of the drawing]

Fig. 1 is a side view showing an embodiment of the falling weight type impact tester of the present invention, Fig. 2 is a front view showing the automatic correction mechanism, and Fig. 3 is a schematic diagram showing the fall height correction situation. FIG. 4 is a curve diagram showing an example of the generated impact acceleration curve and the names of each element of this curve, and FIG. 5 is a block diagram of a system used in the drop weight type impact tester of the present invention. 1...Sample stand, 9...Horizontal cylinder, 10...
Stopper, 11... Ball screw, 12... Pulse motor, 13... Vertical cylinder, 14... Acceleration detector, 17... Computer, 18... Pulse motor drive circuit, 19... Standard value input circuit.

Claims (1)

[Claims] 1. In order to detect the actual impact acceleration, an acceleration detector attached to a free-falling sample stage is used to calculate the speed from the detected actual impact acceleration, and the speed determined from the required impact acceleration is calculated based on the deviation of the speed of the sample. It is characterized by having a correction amount calculation means for calculating a correction amount of the fall height of the table, and an automatic fall height correction mechanism that finely adjusts the free fall start position of the sample table based on the output of the correction amount calculation means. A drop weight impact tester.