JPS5856422B2 - force conversion mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mechanism for converting force into frequency.

FIG. 1 is an explanatory diagram of the principle structure of an embodiment of a conventionally commonly used mechanism for converting force into frequency.

In the figure, 1 is a rod with a uniform cross section fixed at both ends, and 2 is a base of, for example, a casing.

Now, assuming that an axial force S is applied to both fixed ends of the rod 1, there is a difference of l between the axial force S and the lateral vibration frequency f of the rod.
>Kzgr%, there is a relationship as shown in equation (1).

Since the resonant frequency ω is expressed as 2πf, by measuring the resonant frequency of the rod l, the corresponding axial force S can be measured.

In such a transducer, the following conditions must be satisfied in order to achieve highly accurate measurement.

(1) Good stability of frequency f.

In other words, the Q of the vibrator (=salary l) is high.

(11) Frequency change rate Δf/σ per unit stress is large.

That is, the good dust G of such a transducer can be expressed by the following equation.

In the configuration shown in Fig. 1, the applied axial force S can be determined by making the salary l resonate and measuring its resonance frequency ω, but as shown in Fig. 2, the When the is vibrating, a reaction force R is generated at the fixed end of the base 2.
If the base part is not an ideal fixed end, this force becomes a loss and is consumed, causing a decrease in the Q of the salary l.

The present invention solves the above problems.

An object of the present invention is to provide an efficient force conversion mechanism with a simple configuration and low vibration energy loss.

FIG. 3 is a configuration explanatory diagram of an embodiment of the present invention, in which A is a front view and B is a side view.

In the figure, 1 is the vibrator main body, the vibrating part 11, the coupling part 1
2 and a support section 13.

The vibrating part 11 is provided symmetrically in parallel to the central axis A-A,
It is shaped like two plate beams.

Both ends of the coupling part 12 are coupled to one end of each of the vibrating parts 11, and the vibrating part 11 and the coupling part 12 form a mouth shape, and the whole is structured as one vibrator. The support portion 13 vibrationally insulates the vibrator body 1 from the base 2 to which the vibrator body 1 is attached, such as a housing, and also prevents mounting error when fixing the vibrator body 1 to the base 2. It is designed to prevent the occurrence of errors due to misalignment of the center axis, and is made up of seven plate-shaped lexers 131° and 132 that are at right angles to each other, and connects the connecting part 12 and the base 2.
are connected.

3 and 4 are piezoelectric elements respectively attached to the side surfaces of the coupling part 12, as shown in FIG.
is used as an excitation element, and an externally provided amplifier 5
It is connected to the.

Furthermore, the piezoelectric element 4 is used as a vibration pickup element, and its output is fed back to the amplifier 5. An oscillation circuit B is configured.

6 is a frequency measuring device. In the above configuration, as shown in FIG. 3, when the measured axial force S is applied to the vibrator body 1 in the direction of the arrow, when the axial force S changes, the vibrator body The resonant frequency of oscillation circuit B changes, and the oscillation frequency of oscillation circuit B changes accordingly.

Therefore, the oscillation frequency of the oscillation circuit B is determined by the frequency measuring device 6.
The value of the axial force S applied to the vibrator main body 1 can be known by measuring it.

In this case, as shown in FIG. 5, in the vibration mode in which the two vibrating parts 11 and the coupling part 12 vibrate symmetrically about the central axis A-A, the fixed end of the vibrator body 10 to the base 2 has a vibration Part 1
Since the reaction forces R and M generated at the connection point between 1 and the joint 12 are in opposite directions and equal in magnitude, the joint 12
cancel each other out, no force associated with the vibration of the vibrator is generated externally, and even if the support is not ideal,
Energy is not consumed externally from the vibrator body 1.

As a result, a vibrator body with a high Q (large value of good dust G) can be obtained.

FIG. 6 is an explanatory diagram of the main part configuration of another embodiment of the present invention, in which A is a front view and B is a side view.

In this embodiment, four isolation masses 14 are provided, one side of which is fixed to the joint 12, with a flexure 132 sandwiched therebetween symmetrically about the central axis A-A.

As a result, the generated reaction force R1 (moment) M can be made smaller, and the small reaction forces cancel each other out, so that more force is applied to the support point of the vibrator body 1 to the heath 2. You get something that definitely won't happen.

In the above-mentioned embodiment, it was explained that the piezoelectric element 3.4 is attached to the side surface of the coupling part 12, but it is also possible to attach it to the vibrating part 11 as shown in FIG. 7A. Of course.

However, a better Q can be obtained near the side surface of the joint portion 12.

The relationship between the fixed position of the piezoelectric element and Q is shown in FIG. 7B.

Note that if a thin film piezoelectric element is directly formed on the side surface of the vibrator body 1 by vapor deposition or sputtering as the piezoelectric element 3.4, a higher Q can be achieved than in the case where the piezoelectric element is bonded. In addition, since it is formed directly on the side surface of the main body, it is possible to obtain a product with good productivity.

Furthermore, if the transducer main body 1 is made of a magnetic material and an electromagnetic method is used in which the transducer is driven and picked up by a coil, the coil as a drive and pickup element can be made non-contact with the transducer main body 1. Products with good characteristics can be obtained.

Furthermore, if the vibrator main body 1 is directly composed of a piezoelectric material such as crystal, and the vibrator is constructed by attaching electrodes to the piezoelectric element by vapor deposition, etc., the configuration becomes even simpler, the characteristics are good, and the output is Low impedance can be obtained.

In this case, the cut of the crystal and the arrangement of the electrodes may be selected so that the vibrating section 11 undergoes bending vibration.

Furthermore, in the above-mentioned embodiment, it was explained that the vibrating part 11 has a plate beam shape, but it is not limited to this, and may be in the shape of a round bar.In short, even if the opposing vibrating parts have a symmetrical structure Bye.

Furthermore, it goes without saying that either the flexures 131 or 132 may be omitted.

As described above, according to the present invention, it is possible to realize an efficient force conversion mechanism with a simple configuration and low vibration energy loss.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the principle configuration of an embodiment of a conventionally known Kerr frequency conversion mechanism, FIG. 2 is an explanatory diagram of the operation of FIG. 1, and FIG. 3 is an explanatory diagram of the configuration of an embodiment of the present invention. A is a front view, B is a side view, Fig. 4 is an explanatory diagram of the configuration of the oscillation circuit, and Fig. 5 is the third
Fig. 6 is an explanatory view of the configuration of another embodiment of the present invention, where A is a front view, B is a side view, and Figs. 7A and B are the relationship between the fixed position of the piezoelectric element and Q. FIG. 1... Vibrator body, 11... Vibrating part,
12...Connection part, 13...Support part, 1
4...Isolation mass, 2...
Base, 3, 4...Piezoelectric element, 5...
Amplifier, 6... Frequency measuring device, A...
central axis.

Claims (1)

[Scope of Claims] 1. A long-shaft vibrating part that is provided symmetrically in parallel to a central axis and to which the human axial force to be converted is substantially applied in the axial direction, and a connection that connects one end of each of the vibrating parts. A force transducing mechanism comprising a vibrator body comprising a vibrator body, an excitation means for causing the vibrator body to resonate, and a detection means for detecting vibration of the vibrator body. 2 Using a piezoelectric element as an element of the excitation means and detection means,
2. The force transducing mechanism according to claim 1, wherein the piezoelectric element is provided at a connecting portion of the vibrator body. 3. The force transducing mechanism according to claim 2, characterized in that a thin film vapor-deposited piezoelectric element is used as the piezoelectric element. 4. The force conversion mechanism according to claim 1, wherein the vibrator body is made of a magnetic material, and coils are used as elements of the excitation means and the detection means. 5. The force transducing mechanism according to claim 1, wherein the vibrator body is composed of a piezoelectric material and an electrode.