JPS6251523B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for adjusting the resonant frequency of a mechanical vibrator with high efficiency and precision using an automated adjustment device.

Mechanical resonators are generally composed of rod-shaped or piece-shaped metal bodies, and because their natural frequencies (resonance frequencies) are extremely stable, they can be used as oscillators when used in combination with electromechanical transducers such as piezoelectric ceramics. Alternatively, it is widely used as a tuning selection element in the field of communication transmission components. For example, the function of the oscillator is widely used in stable low-frequency oscillators, and the function of the tuning selection element is widely used in mechanical wave devices (mechanical filters).

The mechanical vibrator is mechanically excited by an input signal via the electro-mechanical transducer, and in the excited state, bending vibration, torsional vibration, etc. occur between the plurality of vibration nodes generated on the surface of the mechanical vibrator. Vibration is performed in the vibration state of . The frequency of these vibrations represents the resonant frequency of the mechanical vibrator. Therefore, by slightly changing the factors that determine the frequency of vibration, that is, the physical characteristics of the mechanical vibrator, it is possible to bring the resonance frequency as close as possible to the desired frequency. It goes without saying that the more accurately the resonant frequency matches the desired frequency, the more accurate an oscillator or wave generator can be obtained.

The above-mentioned physical properties of a mechanical oscillator specifically refer to the specific gravity, Young's modulus, rigidity, shape (length, thickness), etc. of the mechanical oscillator, but the former three are actually changed in their properties. However, since it is difficult to change the shape, and it is almost impossible to change the shape minutely, a method is generally used in which the shape, especially the length, is changed.

Conventionally, when fine-tuning the length of a mechanical vibrator to make the resonant frequency a desired frequency, it is common to machine the mechanical vibrator by cutting, polishing, etc.
With this method, a high-precision mechanical vibrator cannot be obtained due to considerable errors, and when mass-producing it, processing time increases, and inspection and measurement of the resonance frequency requires time and effort, resulting in severe inefficiency. It was hot. Therefore, as a processing method that eliminates such defects, a pulsed laser beam is used instead of machining, and the equivalent length of the mechanical vibrator is adjusted by the evaporative destruction effect of the laser beam. This makes it possible to measure the resonant frequency of the mechanical vibrator while it is being processed by light. This method was published in Japanese Patent Application Publication No. 1973-
It is stated in Publication No. 45593. In order to adjust the resonant frequency, the first step is to make a rough adjustment by grinding, and then the second step is to sandblast the mechanical resonator or process it with a laser beam to make a fine adjustment (final adjustment). ) is granted by the Federal Republic of Germany Patent No.
It is described in the specification of No. 1929994.

Furthermore, in addition to the original adjustment in the method of automatically adjusting the actual value of the resonant frequency of a mechanical resonator to a predetermined target frequency described in this specification, selection work is performed when the mechanical resonant frequency is outside the predetermined frequency error range. In order to solve problems such as the need for a device for this purpose, all the work necessary for adjusting mechanical resonators is combined into one device, and the mechanical resonators to be adjusted are arranged continuously. Japanese Patent Laid-Open No. 51-92191 discloses a system that automatically supplies, adjusts, measures, etc.

However, as mentioned above, the performance of a mechanical oscillator (mechanical resonator) largely depends on whether its resonant frequency is close to or coincides with the desired frequency. This is done through two stages of fine adjustment and processing. By the way, when processing using the above-mentioned conventional known method, the temperature of the mechanical vibrator (including piezoelectric vibrator) after rough adjustment has increased, so the density, shape, etc. of Unlike at normal temperature), a frequency difference based on the difference between the resonant frequency at this temperature and the resonant frequency under use results in an error, making it impossible to obtain a highly accurate mechanical vibrator. This means that in the conventional adjustment method using an automatic frequency adjustment device that has a continuous adjustment process, it is impossible to achieve the desired resonant frequency unless fine adjustment is performed after the temperature of the mechanical resonator has stabilized at room temperature. Can not. Therefore, the mechanical vibrator that has been roughly adjusted must be removed from the adjustment device, and after the temperature has stabilized, it must be placed on the adjustment device again, measured, and finely adjusted. For the above reasons, in order to obtain a high-precision mechanical vibrator, it is difficult to perform adjustment using a fully automated and highly efficient adjusting device, and it is difficult to operate the adjusting device economically and manufacture mechanical filters etc. with high efficiency. There was a problem that there was no.

The present invention has been made in view of the above-mentioned problems, and its purpose is to solve the above-mentioned conventional problems, and to achieve the desired resonance in a short time, with high efficiency, and fully automatically, without requiring any manual intervention. An object of the present invention is to provide a frequency adjustment method capable of adjusting the frequency of a mechanical vibrator. The gist of the method of the present invention is as follows: a mechanical vibrator accommodating section equipped with a means for sequentially delivering and supplying mechanical vibrators; The resonant frequency of the mechanical vibrator to be conveyed is measured on the conveyance path through which the mechanical vibrator is conveyed in the conveyance step, and the resonant frequency of the mechanical vibrator to be conveyed is measured at a step position in the middle of the conveyance path, and the mechanical vibrator is processed to substantially shorten the length dimension. A measurement processing section for achieving a desired resonance frequency, a discharge section for the mechanical vibrator, and a control device for controlling the mechanical vibrator storage section, the conveyance path, the measurement processing section, and the discharge section, The resonant frequency of the mechanical vibrator is measured in the measuring and processing section, and those within a predetermined frequency range are processed to the desired resonance frequency and discharged, while those outside the predetermined frequency range are processed at the measurement and processing section. The resonant frequency is processed so as to fall within a predetermined frequency range, the conveyance path is made to go around one more time, the resonant frequency is measured again in the measuring and processing section, and the resonant frequency is controlled and adjusted to a desired resonant frequency. In this way, according to the method of the present invention, a timing period is provided during which the frequency error from the normal temperature stable state due to the temperature rise during rough adjustment converges. Indicates slight. Embodiments of the method of the present invention will be described below with reference to the accompanying drawings.

The figure systematically shows an example of an adjustment device to which the method of the present invention is applied, and shows an unadjusted mechanical vibrator (not shown) that is not adjusted to the desired resonance frequency.
A storage section 1 for accommodating a large number of oscillators, and a well-known vibration aligning and supplying means are provided in this accommodating section 1, whereby the unadjusted mechanical oscillators are sequentially transferred one by one to the conveyance path 2.
It is delivered and supplied to the work holder 3 of. The conveyance path 2 is constructed in a circulating manner and can be implemented, for example, by a turntable or a belt conveyor. The holder 3 holds the unadjusted mechanical vibrator and moves it to the conveyance path 2.
It is transported according to the transport steps of

The resonant frequency of the mechanical vibrator is measured prior to adjustment processing, and when this method is performed using magnetic vibration, the magnetized section 4 is installed along the conveyance path 2, The mechanical vibrator passing through this point is magnetized. In the next step, transport path 2
In the measuring and processing section 5 which measures and processes the resonant frequency of the mechanical vibrator provided along the magnetic field, the mechanical vibrator is excited to vibrate by magnetic force. Since this excited vibration is a unique resonance frequency of the mechanical vibrator, this resonance frequency is collected by a microphone provided in the measurement processing section 5, amplified, and stored in a storage device. The above-mentioned method for measuring the resonant frequency is known, for example, Tokin Technical Review
It is also possible to use the measurement principle of the paper "Measurement method of torsion mode resonator for mechanical filter" described on pages 105 to 109 of Volume 7, No. 1 (published May 1970).

The desired resonance frequency value can be achieved by reducing the mass of the mechanical vibrator based on the measured resonance frequency and gradually increasing the resonance frequency, and in this way, the desired resonance frequency can be achieved. Can be adjusted. As described above, this adjustment method is carried out by processing the end face of the mechanical vibrator using a laser beam, sandblasting, etc. so as to substantially shorten the length of the mechanical vibrator. Based on the above, the next step is to process the unadjusted mechanical vibrator that has been transported to the measurement and processing section 5, which is capable of repeating vibration frequency measurement and processing at the same location by switching over and repeating them at minute intervals. Frequency where the measured resonance frequency ₀ corresponds to a coarser adjustment limit amount than the desired adjustment target frequency
₂ lower frequency i.e. higher than ₋₂ ,
Also, the frequency is lower than the target frequency by the frequency ₁ corresponding to the limit amount that can be finely adjusted, that is, −
When it is lower than ₁ , that is, ₋₂ < ₀ < −
In the case of ₁ , the frequency is lower than the target frequency by the tolerance △, that is, until it becomes higher than -△.
In other words, rough adjustment processing is performed until a relationship of ₀ > _-1 is established.

Also, if ₋₁ < ₀ < −△, then ₀
Fine adjustment processing is performed in the same manner until >-△ is satisfied.

The mechanical vibrators that have undergone fine adjustment, coarse adjustment, and fine adjustment as they are sequentially transported along the transport path 2 as described above have resonance frequencies of -△< ₀ <+△. As a good product,
Those with ₀ >+Δ and ₀ < _-2 are sorted out as defective products by the discharge section 6 and discharged. Items that have been roughly adjusted in the above process are not discharged, but remain mounted on the conveyance path 2, go around the conveyance path 2, have their resonance frequency measured again, and then laser process them to the desired frequency based on the resonance frequency. It is considered to be of good quality. Going around the conveyance path 2 after the above-mentioned rough adjustment is a process of fine adjustment in which the temperature of the mechanical vibrator increases due to the rough adjustment process, and therefore the resonant frequency is measured immediately after and the desired resonant frequency is set. The purpose of this arrangement is to cool the conveyance path 2 while it makes one round, since this would cause an error with the resonant frequency of the mechanical vibrator at room temperature. If necessary, an appropriate number of stages of air supply means 8 may be provided in the middle of one cycle to forcibly promote cooling to room temperature, which will further enhance the effect and increase overall speed and efficiency. This can also be carried out by performing a round of fine adjustment and measuring again to confirm the resonant frequency, or by further fine-tuning it so that it matches or is very close to the desired frequency.

Processing using pulsed laser light for the above-mentioned fine adjustment processing is performed using an industrial laser such as a gas laser or a solid laser, as detailed in the above-mentioned Japanese Patent Application Laid-Open No. 50-45593, and the number of pulses depends on the frequency to be finely adjusted. This is achieved by setting in advance to remove the adjusted amount, controlling by a comparison control command in the control device, and distributing the laser light without concentrating it on one location.

Supply of the unadjusted mechanical vibrator to the work holder 3 on the conveyance path 2, conveyance on the conveyance path 2, magnetization in the magnetization section 4, measurement of the resonance frequency in the measurement processing section 5, memorized resonance frequency Rough adjustment processing or fine adjustment processing based on comparative control based on comparison control, pass/fail judgment discharge 6, furthermore, control and storage of the conveyance path round after rough adjustment processing, reprocessing, etc. are all controlled by the control device (CPU) 7. It is done by twisting. Therefore, according to the method of the present invention, coarse adjustment and fine adjustment of the resonant frequency of a mechanical vibrator can be carried out continuously and fully automatically using a single set of equipment, which is extremely effective for the economical operation of the equipment and the efficient manufacture of amplifying vibrators. Great effect. Since the temperature is automatically restored to room temperature during one cycle, no manual labor or special equipment is required. Since this can be carried out in parallel, there is no time wastage due to parallel processing, and as a matter of course, cooling can be carried out using the above-mentioned process time, resulting in remarkable efficiency. Of course, in the process of the mechanical vibrator going around the conveyance path after the rough adjustment described above, a new mechanical vibrator is inserted under the control of the CPU when the work holder on which the mechanical vibrator is placed passes through the mechanical vibrator accommodating section. It will never be supplied.

As described above, according to the method of the present invention, the resonant frequency of a mechanical vibrator can be adjusted in a short time, with high precision, with high efficiency, and fully automatically using processing methods such as laser light and sand blasting. It is possible to do so, and it can greatly contribute to the demand for adjusting and processing mechanical vibrators as resonators for mechanical wave devices, piezoelectric vibrators, etc. in large quantities with high accuracy.

[Brief explanation of the drawing]

The figure systematically shows an embodiment of an adjustment processing apparatus for explaining the method of the present invention. In the figure, 1 is an accommodation supply section, 2 is a conveyance path, 3 is a work holder, 4 is a magnetization section, 5 is a measurement processing section, and 6
7 is a control device, and 8 is an air supply means.

Claims (1)

[Claims] 1. A mechanical vibrator accommodating section provided with means for successively delivering and supplying mechanical vibrators; a conveyance path on which the mechanical vibrators delivered and supplied from the mechanical vibrator accommodating section are loaded and conveyed in predetermined conveyance steps; Measuring the resonant frequency of the mechanical vibrator to be conveyed at a step position midway through the conveyance path, and processing the mechanical vibrator to substantially shorten its length so that it has a desired resonant frequency. A processing section, a discharge section for the mechanical vibrator, and a control device for controlling the mechanical vibrator housing section, the conveyance path, the measurement processing section, and the discharge section, the mechanical vibrator being conveyed resonates in the measurement processing section. The frequency is measured, and those within a predetermined frequency range are processed to have the desired resonance frequency and discharged, and those outside the predetermined frequency range are processed by the measurement processing section to be within the predetermined frequency range. A method for adjusting the vibration frequency of a mechanical vibrator, in which the conveyance path is made to go around one more time, and the resonance frequency is again measured in the measurement processing section to obtain a desired resonance frequency.