JP2663677B2 - Acceleration measuring device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an acceleration measuring device that applies acceleration to an acceleration sensor and checks the performance of the acceleration sensor based on an output signal of the acceleration sensor.

2. Description of the Related Art Conventionally, as shown in FIG. 3, this type of acceleration measuring device includes a rotating arm 33 that revolves around a center axis 31 in a direction of an arrow 32, and a radius r from the center axis 31 of the rotating arm 33.
And a turntable 35 that is attached to the end of the rotary table and rotates in the direction of arrow 34. An acceleration sensor 36 as a specimen is mounted on the rotary table 35, and a rotating arm 33 is provided.
The acceleration is determined by the revolution speed of the rotary table 35
The applied frequency is determined by the rotation of the motor, and the magnitude of the acceleration at a certain applied frequency is measured.
Assuming that the acceleration at this time is α, the applied frequency f and the radius r, there is a relationship α = r (2πf) ² .

As another apparatus for measuring acceleration, there is a simple pendulum type apparatus using a gravitational acceleration g as shown in FIG. In this device, a lever 42 having a length 1 serving as a single pendulum whose base end is swingably fixed to a top plate 41 and
And a holder 43 fixed to the tip. An acceleration sensor 44, which is a specimen, is set in the holder 43, and an arrow
The acceleration generated by alternately swinging in the directions of 45 and 46 is measured. At this time, the relationship between the gravitational acceleration g, the lever length l, and the applied frequency (also called period) T is as follows. become that way. The relationship among the acceleration α, the gravitational acceleration g, the lever length 1 and the head S is α = − (g / l) S.

Problems to be Solved by the Invention However, the conventional acceleration measuring device has the following problems.

First, in the device shown in FIG. 3, since the speed of rotation and revolution can be independently varied, there is an advantage that the acceleration α can be independently varied for one applied frequency f, but the rotating part is rotated and revolved. Because of the two types, mechanical vibration noise is easily generated, and electric noise is easily generated due to the presence of the electric sliding contact portion. Further, the size of the apparatus tends to be large and expensive.

Next, in the apparatus shown in FIG. 4, in order to cause the acceleration sensor 44, which is the specimen, to swing at a low frequency or to increase the applied frequency T, the above equation is used. Therefore, the lever length l must be increased, and the device becomes large. In addition, the acceleration α tends to vary depending on how the lever 42 is released, and it is difficult to keep the posture of the acceleration sensor 44, which is the specimen, constant at all times.

Further, it is extremely difficult to measure any of the above acceleration measuring devices in an ultra-low frequency range of 1 Hz or less.

The present invention is intended to solve such a conventional problem, and is capable of measuring acceleration at an extremely low frequency range of an applied frequency of 1 Hz or less and at a low acceleration with high accuracy, and is a low-cost and compact acceleration measurement device. It is intended to provide a device.

Means for Solving the Problems In order to achieve the above object, the present invention uses a DC motor or a pulse motor or the like that can control the rotational speed, and converts the power of the rotational motion into a linear reciprocating motion via a crank mechanism. By the conversion, a smooth sinusoidal motion characteristic is created with a simple configuration.

Operation The present invention has the following effects by the above configuration. In other words, by using the crank mechanism, the motion characteristics of the portion where the test sample is set are made into an accurate sinusoidal curve, and the test sample performs a sinusoidal motion by the suspension method, so that there is no external vibration transmission, Acceleration measurement can be performed without increasing the size of the device even in the ultra-low frequency range of 1 Hz or less and the low acceleration range of 0.1 G or less.By controlling the rotation speed of the DC motor, the frequency and This has the effect that the magnitude of the acceleration can be easily changed.

Embodiment FIG. 1 shows the configuration of an embodiment of the present invention.
In FIG. 1, reference numeral 1 denotes a crank mechanism, and a DC motor 11
Is fixed by a key 3 to an output shaft 2 that transmits the rotation of the motor through a speed reducer (not shown). Reference numeral 4 denotes a wire having one end attached to a roller 12 rotatably provided on the crank mechanism 1, and a weight 7 provided at the other end to prevent slack of the wire 4 and stabilize the movement. ing. Reference numeral 5 denotes a guide roller for guiding the wire 4 and preventing the weight 7 from rolling. Reference numeral 6 denotes a test acceleration sensor, which is attached to the weight 7 so as to sense vertical acceleration.

Next, the operation of the above embodiment will be described. In response to an input command from a DC motor controller (not shown), the DC
The crank mechanism 1 is driven by an arrow 9 via the motor 11 and the speed reducer.
Starts a rotational movement in the direction of
Further, the test acceleration sensor 6 provided here is caused to reciprocate linearly in the direction of arrow 8 with a sinusoidal motion characteristic as shown in FIG. Since the test acceleration sensor 6 outputs an output according to the magnitude of the acceleration applied by this movement, the output value of the test acceleration sensor 6 corresponding to the applied acceleration is measured by an output device such as an oscilloscope or a pen recorder. Becomes The applied frequency and the magnitude of the applied acceleration are determined by changing the number of rotations of the DC motor 11.

Therefore, according to the above embodiment, the test acceleration sensor 6 has a structure suspended by the wire 4 via the weight 7, and the wire 4 is guided by the guide roller 5. Vibration is hardly transmitted, and there is no sliding portion. Therefore, the test acceleration sensor 6 can realize a motion having a smooth sine curve with very little vibration, and transmission of vibration noise from the outside can be achieved. There is an effect that acceleration can be measured with high accuracy in a very low frequency range of 1 Hz or less and at a low acceleration with high accuracy.

In the present embodiment, the wire is attached to the roller 12 provided on the crank 11, but this may be achieved by using a strong thread.

Effect of the Invention As is clear from the above embodiment, the present invention gives a sinusoidal motion characteristic to the acceleration sensor which is a test object by using a crank mechanism, and furthermore, since the configuration of the measuring device is a hanging type, The transmission of vibration noise from the sensor is low, and it is possible to measure the acceleration at low acceleration in the ultra-low frequency range of 1 Hz or less with high accuracy and high reliability.
Moreover, there is an effect that an inexpensive and compact acceleration measuring device can be realized.

[Brief description of the drawings]

FIG. 1 is a front view of an acceleration measuring device according to an embodiment of the present invention, FIG. 2 is a characteristic diagram showing an example of a sinusoidal motion characteristic given to a test acceleration sensor, and FIG. FIG. 4 is a front view of another conventional acceleration measuring device. 1... Crank mechanism, 2... Output shaft, 3.
... wire, 5 ... guide roller, 6 ... acceleration sensor for test, 7 ... weight, 11 ... DC motor, 12 ... roller.

Claims (1)

(57) [Claims] 1. A DC motor, a crank that rotates by rotational power transmitted from the DC motor, a wire attached to the crank, a guide roller that guides the wire, and a lower end of the wire, An acceleration measuring device comprising a weight that reciprocates in a vertical direction and holds an acceleration sensor as a specimen.