JPH0238911B2 - - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to accelerometers, particularly servo accelerometers.

BACKGROUND ART AND PROBLEMS Prior to the explanation of the present invention, the outline of the accelerometer disclosed in Japanese Patent Application No. 58-188924 and Japanese Patent Application Laid-Open No. 58-90174, which was previously proposed by the applicant, will be explained in the first and This will be explained with reference to FIG.

1 and 2 are a sectional view and a partially removed plan sectional view of the previously proposed accelerometer described above.
In the figure, reference numeral 1 denotes a rod-shaped pendulum for detecting acceleration, which is supported by a flexible joint, ie, a hinge 3, having a thin wall portion 2, that is, a flexible portion. This pendulum 1 can rotate only in the XX direction parallel to the paper plane of FIG. 1, using the thin wall portion 2 of the hinge 3 as a fulcrum. One end of the hinge 3 is securely attached to the hinge mounting portion 5 of the first base or frame 4 via a hinge pressing plate 6, for example, with a screw or the like. In addition, the pendulum 1 has two cylindrical torquer coils 7, 7' attached to the rotation axis of the thin part 2 of the hinge 3, that is, 0-
It is installed perpendicular to the 0 axis. A disk-shaped permanent magnet 8 and a cylindrical pole piece 9 are attached to the first frame 4 by, for example, an adhesive so that they can be inserted into one of the torquer coils 7 without contacting them. Since this first frame 4 is made of electromagnetic soft iron, it forms a magnetic circuit with the pole piece 9 using a permanent magnet 8 and serves as a yoke (return path). , and the torquer coil 7 constitute one torquer. In this first frame 4,
Two light receiving elements 10 and 1 that detect the deflection of the pendulum
0' and a light emitting element 11 are attached.

On the other hand, the second base or frame 12, like the first frame 4, is made of electromagnetic soft iron, and is arranged so that it does not contact the torquer coil 7' and is inside it.
Permanent magnet 1 glued to this second frame 12
3 and the pole piece 14 constitute a magnetic circuit and serve as a yoke. The fitting portion 15 of the first frame 4 is connected to the fitting portion 16 of the second frame 12.
Insert and integrate the two.

The first frame 4 and the second frame 12 are provided with stoppers 17 and 18, respectively, which limit the operating range of the pendulum 1.The stoppers 17 and 18 are rotated by screws, respectively, and limit the pendulum 1. It is possible to freely adjust the range.

The above-mentioned components already have a function as an accelerometer, and these are fixed to the case 19 with a plurality of screws 20 to integrate them with the case 19, and a characteristic name plate/lid 21 is glued to the case 19. death,
The inside of the case 19 can be kept airtight.

Light receiving elements 10 and 10' forming a deflection detector
External terminals 22 such as lead wires (not shown) for supplying electrical signals from the terminal case 23 and feedback current to the torquer coils 7 and 7' are connected to the terminal case 23.
In addition, the terminal case 23 is hermetically bonded to the case 19 so that one end thereof is inside the case 19. The electrical system of the internal device is connected through the opening 24 in the center of the terminal case 23, and while the inside of the case 19 is filled with a vacuum or an inert gas (for example, helium gas), the terminal case 23 is connected to the opening 24. case 1
9 is maintained in an airtight state to prevent parts from deteriorating and maintain stable performance over a long period of time.

In the accelerometer with the above configuration, Case 1
When acceleration acts in the central axis XX direction of 9,
The pendulum 1 is slightly deviated about the thin part 2 of the hinge 3 as a fulcrum, and is shielded or divided by the pendulum 1 from the light emitting element 11, and the light incident on the light receiving elements 10 and 10' of the deviation detector changes. From these, an electrical signal corresponding to the deviation can be obtained. A current proportional to this electric signal is fed back to the torquer coils 7, 7', thereby controlling the pendulum 1 to the light receiving elements 10 and 1.
The electrical signal output at 0' is constrained to zero.
Since this electric signal, that is, the restraining current, is proportional to the acceleration, the input acceleration can be determined by measuring this current.

In addition, in FIG. 2, 19-3 is a flange-shaped portion 19-4 of the case 19 used when attaching the above-mentioned accelerometer to an object whose acceleration is to be measured.
This is the mounting hole provided in the.

However, in the previously proposed accelerometer, the stoppers 17 and 18 were constructed to abut against the tip of the rod-shaped pendulum 1, so in the non-operating state, the pendulum 1 - When vibration or impact is applied in the X direction, the thin part 2 of the hinge 3
A reaction force (shearing force) proportional to the mass of the pendulum 1 and the angular velocity around the center of gravity acts on the pendulum 1, and excessive stress is generated in the thin part 2 of the hinge 3, and in extreme cases, deformation etc. occur here. There is a serious drawback.

OBJECTS OF THE INVENTION The invention therefore seeks to provide an accelerometer that does not have the above-mentioned drawbacks.

Summary of the Invention In the accelerometer according to the present invention, the above drawbacks are solved by aligning the thin wall portion of the hinge with the center of impact and providing a stopper at a position corresponding to the impact point of the pendulum. This is the same phenomenon as when hitting a ball in the sweet spot, such as in baseball or tennis, the impact reaction force is not felt in the hand holding the bat or racket.

Embodiment Hereinafter, an embodiment of the present invention will be described based on the drawings. FIG. 3 is a longitudinal sectional view showing one embodiment of the present invention.

In this figure, the same members as those in FIGS. 1 and 2 are given the same numbers, and their explanations will be omitted.

The difference between the example of the invention shown in FIG. 3 and the first and second examples is that in this example of the invention, the first
and the flange-shaped part 19- of the accelerometer shown in FIG.
4 and the case 19 having the mounting reference surface 19-2, and instead, a part of the first frame 4 is made into a flange-like portion 4-1, and its lower surface is made into the mounting reference surface 4-2. That is, in this embodiment of the invention shown in FIG. 3, the case 19 has a flange-like portion 19-4 shown in FIGS. The first frame 4 is formed as one block in such a shape that the outer cylindrical part is fixed integrally. Accordingly, in this example of the invention, the terminal case 23 is attached to the first frame 4 at its flange portion 4-1 (which corresponds to the flange portion 19-4 in FIGS. 1 and 2). directly in the vicinity of the Incidentally, the lower surface of this flange-shaped portion 4-1 becomes an attachment reference portion 4-2.

Another difference between the example of FIG. 3 of the present invention and the examples of FIGS. 1 and 2 is that in the present invention, the stopper 1
7 and 18 are disk-shaped, and these are fixed on the inner end surfaces of the pole pieces 9 and 14 in the vicinity of the point of impact of the pendulum 1, respectively, so that the thin part 2 of the hinge 3 is in the vicinity of the point of impact of the pendulum 1. The pendulum 1, hinge 3, etc. are designed to coincide with the center.

Other configurations include the example of the present invention shown in FIG.
Since they are substantially the same as the examples shown in FIGS. 1 and 2, they are given the same reference numerals, and detailed description thereof will be omitted.

Note that FIG. 4 is a plan cross-sectional view with a part of FIG. 3 removed. Furthermore, in the example of the present invention described above, the mounting hole 1
9-3 is bored in the flange-like portion 4-1.

Next, the operation of the embodiment of the present invention described above will be explained with reference to FIG. 5, which schematically shows the main parts thereof. In FIG. 5, when vibration or impact acceleration is applied to the first frame 4, which is the base of the accelerometer, the pendulum 1 rotates around the point Q of the thin part 2 of the hinge 3, but the stoppers 17, 18 Its excursion is limited by Now, the mass of the pendulum 1 is m, its center of gravity is G, the radius of inertia of the pendulum 1 around the center of gravity is k, and the distance between the center of gravity G of the pendulum 1 and the center point Q of the thin part 2 of the hinge 3 is the center of gravity. If the distance between G and the stoppers 17 and 18 is S, the following relationship holds true.

By setting the positions of the stoppers 17 and 18 to values that satisfy the above formula (1), the pendulum 1 moves to the stoppers 17 and 1.
8, no load is applied to the thin wall portion 2 of the hinge 3.

That is, in the above-mentioned embodiment of the present invention, based on the above-mentioned operation, the thin part 2 of the hinge 3 is made the center of the so-called well-known impact with respect to the pendulum 1, and the stopper 17,
By aligning the point 18 with the point of impact, the deflection of the pendulum 1 is restricted and the stress generated in the thin portion 2 of the hinge 3 is suppressed.

Effects of the Invention As explained above, according to the present invention, the following effects can be obtained.

By providing the stoppers 17, 18 and discs on the inner end surfaces of the pole pieces 9, 14,
In order to limit the deflection of the pendulum 1 at the point of impact in the longitudinal direction of the pendulum 1, when the acceleration is not activated, all of the velocity energy of the pendulum 1 generated by the vibration shock is absorbed by the collision with the stopper. The impact is dissipated and becomes the center of impact on the thin wall portion 2 of the hinge 3, and no load is applied at all. That is, the thin wall portion 2 of the hinge 3 is not deformed at all due to vibration or impact.
An accelerometer with excellent vibration and impact performance can be obtained.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of the previously proposed accelerometer, Fig. 2 is a plan sectional view with a part of Fig. 1 removed, Fig. 3 is a longitudinal sectional view of an embodiment of the present invention, and Fig. 4. 5 is a plan sectional view with a portion thereof removed, and FIG. 5 is a schematic diagram for explaining the operation of the present invention. In the figure, 1 is a pendulum, 2 is a thin wall part, 3 is a hinge, 4 is a first frame, 4-1 is a flange-like part, 4-2 is a mounting reference plane, 7, 7' is a torquer, 8,
13 is a permanent magnet, 9 and 14 are pole pieces, 1
0 and 10' are light receiving elements, 11 is a light emitting element, 12 is a second frame, 15 and 16 are fitting parts, 17 and 1
8 indicates each stopper.

Claims (1)

[Claims] 1. A flexible joint, a base to which one end of the flexible joint is fixed, a pendulum fixed to the other end of the flexible joint, and a pendulum that is connected to the pendulum from the fixed part of the base. The base includes a torquer that generates a torque proportional to the acceleration inputted by the user, and a deflection detection device that electrically detects the relative deflection between the fixed part and the pendulum. The first frame has a fixed part of the flexible joint, a fixed part of the deflection detection device, and a fitting part with the second frame, and In an accelerometer in which a fixed part and a fixed part of the deflection detection device are provided on a first frame, the flexible joint is made to be the center of impact of the pendulum, and the deflection stopper of the pendulum is controlled. The following formula S=k ² /S (where k is the radius of inertia around the center of gravity of the pendulum, S is the distance between the center of gravity of the pendulum and the center of the thin part of the flexible joint, and S is the distance between the stopper and the center of the flexible joint. (distance between the center of gravity of the pendulum and the center of gravity of the pendulum).