JPH073340Y2 - Acceleration tester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an acceleration tester used for testing an airbag sensor, for example.

[Prior Art] An acceleration tester for performing an operation confirmation test of an acceleration sensor for detecting an operation timing of an airbag in an airbag unit mounted on an automobile or the like and used for saving lives in a vehicle collision. One is an electromagnetic solenoid type in which a mover side having a test table on which a sample is mounted is rapidly driven by an electromagnetic force to obtain a desired collision acceleration for testing.

Figure 3 shows this electromagnetic solenoid type tester.
In the figure, reference numeral 1 denotes an E-shaped stator (field yoke) which is made of a magnetic material and to which a field coil (field coil) 2 is attached. A track 3 extends horizontally from a central leg 1A extending through the field coil 2, and the other end of the track 3 is supported by a receiving portion 4 located at a predetermined distance from the central leg 1A. Reference numeral 5 denotes a cylindrical air-core mover (aluminum armature coil) with openings at both ends, and free wheels are provided on the upper and lower inner circumferences on one end side.
6U and 6D are attached, and a test stand 7 for mounting a test piece (acceleration sensor) 8 and sensors extends from the other end, and a free wheel 6C is attached to the lower side of the test stand 7. It is worn.
The mover 5 is fitted onto the central leg 1A by engaging the free wheels 6U and 6D with the upper and lower surfaces of the central leg 1A, and the free wheel 6C of the test stand 7 engages with the upper surface of the track 3. Reference numeral 9 is a power supply device that supplies electric power to the mover 5, 10 and 11 are power supply lines, and 12 is a field power supply device.

In this configuration, when the test piece 8 is tested, a field current _If is passed through the field coil 2 and the power supply device 9 is given an acceleration command P _g as shown in FIG. I _a
Power is supplied to the mover 5 through the feeder line 10 so that the envelope waveform of the waveform becomes the waveform of FIG. As a result, with respect to the mover 5,
A thrust force g directed in the direction of the solid arrow in the figure acts.

Thrust g = K × I _a × I _f (1) In response to this thrust g, the mover 5 is rapidly accelerated and the central leg 1A
Then, the vehicle 8 travels on the track 3 and is accelerated to a predetermined test collision acceleration, and the sample 8 is operated.

[Problems to be solved by the device]

By the way, the power of the envelope short-circuit waveform given to the mover 5 is
When the acceleration command is amplified and generated by the PWM type inverter, the value of the acceleration command at the time of the low acceleration test becomes small when the test acceleration range is wide, for example, 5g to 100g. The current also becomes a low level, the resolution is lowered, the deviation of the actual output waveform from the desired output waveform is increased, and the test accuracy is lowered.

This invention was made to solve the above problems,
An object of the present invention is to provide an acceleration tester capable of performing a highly accurate test over a wide range of test accelerations.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the present invention commands the field weakening field command when the test acceleration is in the low range, and increases the acceleration command in proportion to the ratio of the test acceleration and the field command. It is configured to be.

[Action]

In this invention, when the test acceleration is in the low range and the value of the acceleration command is at a low level, the field command is switched to the weak field, and the acceleration command increases by that amount. It is possible to obtain a desired test acceleration without lowering the resolution of.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, 21 is a single-phase AC power supply, 22 is a rectifier, and 23
Is an electrolytic capacitor, 24 is an inverter that functions as a power amplifier, and includes four power transistors T _R1 , T _R2 , T
_A bridge connection of _R3 and _TR4 is provided, and a mover (armature coil) 5 is inserted between the AC output terminals A and B.
D is a flywheel diede.

A command device 25 sends an acceleration command P _g80 corresponding to the input test acceleration g (for example, it is in a high range of about ₈₀ g and is represented as g ₈₀ ). An inverter controller 26 has a PWM signal generation circuit 27 and a base drive circuit 28, and supplies a base drive signal to the transistors T _R1 and T _R4 of the inverter 24. The field power supply device 12 is a converter that is composed of a bridge circuit of a controllable rectifying element Sh and is phase-controlled,
Gate controller 30 that receives field command P _f from field commander 29
Receives the gate signal sent by.

Command unit 25 is given the test acceleration g ₈₀ and other parameters, and calculates the acceleration command P _g80. This acceleration command P _g80 is the field current _If and the current flowing through the coil of the mover 5.
It is determined that I _a has the relationship of the above formula (1).
In this case, the field磁指Decree 29 sends field磁指old P _fH.

In this configuration, when the command device 26 sends out the acceleration command P _g80 at every predetermined sampling interval T _s , the PWM signal generation circuit 27
Compares this with a carrier wave (eg carrier frequency 6KHz) to create a PWM signal. The base drive circuit 28 generates a base drive signal based on this PWM signal to generate the transistors T _R1 and T _R1.
Supply to the base of _R4 . This allows both transistors T _R1
And _TR4 start ON / OFF switching operation, and the mover 5 has a current I _a whose envelope waveform is similar to that of the acceleration command P _g.
(Maximum value, for example, 300 amperes) is supplied, and the mover 5 is rapidly accelerated to reach a predetermined collision acceleration g. The acceleration command P _g80 is actually created in consideration of the mechanical loss L such as the friction loss of the mover 5. In reality, the level shown by the dotted line in FIG. 2 contributes to the acceleration of the mover 5. To do. The transistors T _R2 and T _R3 have _a braking current (reverse polarity to I _a ) in the mover 5.
Used to drain.

When the test acceleration g is in the low range of, for example, about 10 g, the command device 25 sends the acceleration command k × P _g10 at a level at which the resolution becomes a desired value. The field commander 29 sends out a field command of P _fL = P _fh × 1 / k.

Therefore, in this case, the field current I _f is smaller than that in the above case.
Although it is reduced to 1 / k and the field weakening occurs, the output current I _a of the inverter 24 is large, so sufficient resolution can be obtained,
Since the current I _a with less distortion can be supplied to the mover 5, a good test can be performed.

In this embodiment, two commanders 25 and 29 are provided, but
Acceleration command P _g and field command with one command device, for example command device 25
The P _f may be made to operation.

Further, in the present embodiment, when the test acceleration g is in the low frequency range, a constant field weakening field is instructed, but a fine field weakening field according to the magnitude of the test acceleration g is used. Good.

[Effect of device]

As described above, the present invention weakens the field to prevent the output of the power supply device functioning as an amplifier from being significantly reduced when the test acceleration is small. Can obtain sufficient resolution over the entire range and can output a waveform faithful to the acceleration command from the power supply device. Therefore, good test accuracy can be obtained over the entire range of the test acceleration. it can.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a waveform diagram showing an output of a commander in the above embodiment, and FIG. 3 is an example of an acceleration tester to which the above embodiment is applied. It is a partial cross section side view. 1 ... Stator, 2 ... Field coil, 5 ... Mover, 9 ...
… Power supply, 12 …… Field power supply, 24 …… Inverter,
25 …… commander, 29 …… field commander.

Claims (1)

[Scope of utility model registration request] 1. An E-shaped stator equipped with a field coil, a mover which is an air-core coil externally fitted on a central leg of the stator so as to be able to run, and a member integrally provided on the mover. A test stand, a power supply device that amplifies an acceleration command corresponding to the test acceleration and supplies the mover to the mover, and a field power supply device that receives a field command and supplies DC power to the field coil. If it is a range, the above field command commands field weakening,
An acceleration tester, wherein the acceleration command is increased in proportion to a ratio of the test acceleration and the field command.