JPH09541A - Preset rotation speed maintenance device for dental handpiece - Google Patents

Abstract

PURPOSE: To easily and properly maintain the number of revolutions of a drive mechanism at a preset value, regardless of a no-load or a loaded condition, and improve cutting efficiency by providing a rotation speed detection means for detecting the number of revolutions of the drive mechanism and a rotation speed adjusting means for correcting a difference between the detected number of revolutions and the preset number of revolutions. CONSTITUTION: A microphone 11 is provided within a joint 21 of an exhaust pipe 22b where compressed air flows, and a sound pressure of a noise generated due to rotating motion of an air turbine is converted to an electrical signal, wherever necessary. An amplifier 12 and an electrical filter 13 shape the electrical signal and a frequency thereof is converted to voltage via an FV converter 14, thereby providing converted voltage as an index to show a speed of the air turbine. Also, a comparator 15 makes a comparison between the converted voltage and reference voltage corresponding to the preset number of revolutions, and a resultant difference is amplified with an amplifier 16. Furthermore, a compressed air supply source 22 is provided with a control valve 17 for correcting the difference on the basis of an amplified value, thereby adjusting feed volume of the compressed air.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for maintaining a set rotational speed of a dental handpiece, and more particularly, to a dental handpiece in which a rotational speed of a drive mechanism thereof is set to a predetermined value regardless of whether there is no load or no load. The present invention relates to a device for maintaining a set rotational speed of a dental handpiece.

[0002]

2. Description of the Related Art Conventionally, a drive mechanism for a dental handpiece is appropriately selected from an air turbine or an air motor which is rotationally driven by compressed air, and a small electric motor which is rotationally driven by meshing a plurality of gears. However, a load is added to the torque during tooth cutting, causing a reduction in the number of revolutions. In principle, it is also possible in these drive mechanisms to raise the number of rotations when there is no load so that the required number of rotations can be obtained even if a load is applied to the torque during tooth cutting. is there.

[0003]

However, if the number of rotations of the drive mechanism is unnecessarily increased as described above, when no load is applied,
There is a drawback that the bearing of the drive mechanism is always burdened with a large load regardless of the load, the bearing may be damaged, and the cutting efficiency is significantly reduced in the tooth cutting work.

The present invention focuses on the above-mentioned drawbacks of the prior art and solves this problem. The object of the present invention is to rotate a drive mechanism in a dental handpiece regardless of whether the drive mechanism is unloaded or loaded. (EN) Provided is a device for maintaining a set rotational speed of a dental handpiece, which can easily and surely maintain the number at a predetermined value and improve cutting efficiency.

Another object of the present invention is to set the rotational speed of a drive mechanism to a predetermined value in a dental handpiece regardless of whether it is unloaded or loaded, and without adding a load associated with detection to the torque of the drive mechanism. It is an object of the present invention to provide a set rotational speed maintaining device for a dental handpiece, which can be easily and surely maintained to improve cutting efficiency.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned object, and its gist is to set rotation for maintaining the rotation speed of a drive mechanism of a dental handpiece at a predetermined value. A number maintaining device, comprising: a rotation speed detecting means for detecting a rotation speed of the drive mechanism; and a rotation speed adjusting means for correcting a difference between the detected rotation speed and a preset rotation speed. It is in the set rotation speed maintenance device of the dental handpiece.

As the rotation speed detection means, for example, means for detecting the rotation speed of the drive mechanism based on the frequency of noise generated by rotation of the drive mechanism, or means for electrically or mechanically counting the rotation speed of the drive mechanism. Can be adopted. In particular, if the above-mentioned means for detecting the number of revolutions based on the frequency of noise is used, the number of revolutions can be accurately detected without adding a load accompanying the detection to the torque of the drive mechanism.

As the rotation speed adjusting means, when the drive mechanism is an air turbine or an air motor, means for adjusting the amount of compressed air supplied from the compressed air supply source, and the drive mechanism are small electric motors. In the case of a motor, appropriate means such as means for adjusting the applied voltage is adopted.

According to this aspect, in the dental handpiece, the rotation speed of the drive mechanism can be easily and reliably maintained at a predetermined value regardless of whether there is no load or load, and the cutting efficiency thereof can be improved. it can.

Another aspect of the present invention is characterized in that the rotation speed detecting means comprises means for detecting the rotation speed based on the frequency of noise generated by the rotation of the drive mechanism. According to this aspect, in the set rotation speed maintaining device of the handpiece, in the dental handpiece, the rotation speed can be changed without load, regardless of load, and without adding a load accompanying detection to the torque of the drive mechanism. By detecting noise consisting of a proportional frequency, the number of revolutions can be accurately detected, and the number of revolutions of the drive mechanism can be easily set to a predetermined value.
Moreover, the cutting efficiency can be reliably maintained and the cutting efficiency can be improved.

Further, according to the present invention, when the means for detecting the number of revolutions based on the frequency of the noise generated by the rotation of the drive mechanism is adopted as the number of revolutions detecting means as described above, specifically, For example, in a dental handpiece provided with a drive mechanism that is rotationally driven by compressed air, a set rotational speed maintaining device that maintains the rotational speed of the drive mechanism at a predetermined value, the sound pressure of noise generated by the rotation of the drive mechanism. Sound pressure-current conversion means (microphone) for converting into an electric signal, and frequency-voltage (hereinafter referred to as FV) conversion means for converting the frequency of the electric signal converted by the sound pressure-current conversion means into a voltage ( FV converter), comparison means (comparator) for comparing the conversion voltage converted by the FV conversion means with a preset reference voltage, and the conversion voltage and reference compared by the comparison means. Characterized by comprising and an adjusting means for correcting the supply amount of the compressed air on the basis of the difference between the pressure, can be achieved in the manner set rotational speed maintaining apparatus of the dental handpiece.

A microphone is used as the sound pressure-current conversion means, and the sound pressure is converted into an electric signal in order to detect the frequency of noise that changes in proportion to the number of revolutions in the drive mechanism. The converted electric signal is preferably amplified by an amplifier and shaped through an electric filter, whereby irrelevant noise can be cut and the number of rotations can be accurately detected.

The FV converting means detects the frequency of the converted electric signal, that is, the voice waveform, and converts it into a voltage. The conversion voltage converted here is compared with the reference voltage corresponding to the preset reference rotation speed by the comparison means, and the difference is corrected by the adjustment means.

Therefore, as described above, in the dental handpiece, noise having a frequency proportional to the rotation speed is applied regardless of whether the load is unloaded or not loaded and the torque of the drive mechanism is not loaded with the detection. By detecting the rotational speed, the rotational speed can be accurately detected, the rotational speed of the drive mechanism can be easily and surely maintained at a predetermined value, and the cutting efficiency can be improved.

[0015]

In the set rotational speed maintaining device for the dental handpiece of the present invention, the rotational speed of the drive mechanism is detected by the rotational speed detecting means, and the rotational speed that is preset based on the detected rotational speed is corrected. Correct by means. Therefore, in the dental handpiece, the rotation speed of the drive mechanism can be easily and reliably maintained at a predetermined value regardless of whether there is no load or no load.

Further, in another set rotational speed maintaining device for a dental handpiece of the present invention, the rotational speed detecting means detects the rotational speed based on the frequency of noise generated by the rotation of the drive mechanism, and the detected rotational speed is detected. The number of rotations preset based on the number of rotations is corrected by the number-of-rotations correction means. Therefore, in the dental handpiece, the rotational speed can be accurately detected from the noise having the frequency proportional to the rotational speed without load, regardless of the load, and without adding the load accompanying the detection to the torque of the drive mechanism. It is possible to easily and reliably maintain the rotation speed of the drive mechanism at a predetermined value.

[0017]

Embodiments of the present invention will be described below with reference to the accompanying drawings, but the present invention is not limited thereto.

FIG. 1 is a schematic view showing an embodiment of a set rotational speed maintaining device for a dental handpiece according to the present invention, and FIG. 2 shows a dental handpiece adopting the set rotational speed maintaining device of FIG. FIG. 3 is a schematic perspective view showing the joint of FIG. 2 in an enlarged manner.

In FIG. 1, reference numeral 10 denotes a dental handpiece 20 (FIG. 2) which employs an air turbine (not shown) which is rotationally driven by compressed air as a drive mechanism, and maintains the rotational speed of the air turbine at a predetermined value. A set rotation speed maintenance device according to the present invention, wherein the set rotation speed maintenance device 1
0 is a microphone 11 that converts sound pressure of noise generated by rotation of an air turbine into an electric signal at any time, and an electric signal converted by the microphone 11 is shaped by an amplifier 12 and an electric filter 13, and its frequency is An FV converter 14 for converting into a voltage, a comparator 15 for comparing the converted voltage converted by the FV converter 14 with a reference voltage corresponding to the rotation speed preset by the rotation speed setting unit 18, and the comparator An amplifier 16 amplifies the difference between the converted voltage and the reference voltage compared in 15, and a control valve 17 that corrects the amount of compressed air supplied based on the difference.

The microphone 11 is arranged in the exhaust pipe 22b through which the compressed air in the joint 21 flows (FIG. 3), and converts the sound pressure of noise generated by the rotation of the air turbine into an electric signal at any time.

In the amplifier 12 and the electric filter 13,
The electric signal converted by the microphone 11 is shaped.
The frequency of the shaped electric signal is converted into a voltage by the FV converter 14 to obtain a converted voltage which is an index indicating the rotation speed of the currently rotating air turbine.

The converted voltage is compared with a reference voltage corresponding to a preset rotational speed by a comparator 15, and the difference is amplified by an amplifier 16. A control valve 17 is provided in the compressed air supply source 22 that supplies compressed air to the air supply pipe 22a so as to correct it based on the amplified difference, and the supply amount of the compressed air is adjusted.

[0023]

According to the set rotational speed maintaining device for a dental handpiece of the present invention, the rotational speed of the drive mechanism is detected by the rotational speed detecting means, and the rotational speed is preset based on the detected rotational speed. Since the rotation speed is corrected by the rotation speed correction means, the rotation speed of the drive mechanism can be easily and surely maintained at the predetermined value regardless of whether there is no load or load, and the cutting efficiency can be improved.

According to another set rotational speed maintaining device for a dental handpiece of the present invention, the rotational speed detecting means detects the rotational speed based on the frequency of noise generated by the rotation of the drive mechanism, and the detected rotational speed is detected. Since the preset number of rotations is corrected by the number-of-rotations correction means based on the number of rotations, the load can be accurately adjusted regardless of whether there is no load or load, and the torque of the drive mechanism is not subject to detection load. The number of rotations can be detected, the number of rotations of the drive mechanism can be easily and surely maintained at a predetermined value, and the cutting efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of a set rotational speed maintaining device for a dental handpiece according to the present invention.

FIG. 2 is a schematic view showing a dental handpiece in a mode in which the set rotation speed maintaining device of FIG. 1 is adopted.

FIG. 3 is a schematic perspective view showing a joint of FIG. 2 in an enlarged manner.

[Explanation of symbols]

 10 set rotation speed maintenance device 11 microphone 12 amplifier 13 filter 14 FV converter 15 comparator 16 amplifier 17 control valve 18 rotation speed setting unit 20 dental handpiece 21 joint 22 compressed air supply source

Claims (2)

[Claims] 1. A set rotational speed maintaining device for maintaining the rotational speed of a drive mechanism of a dental handpiece at a predetermined value, the rotational speed detecting means for detecting the rotational speed of the drive mechanism, and the detected rotational speed. And a rotation speed adjusting means for correcting a difference between the rotation speed and a preset rotation speed. 2. The dental handpiece according to claim 1, wherein the rotation speed detecting means comprises means for detecting the rotation speed based on the frequency of noise generated by the rotation of the drive mechanism. Set rotation speed maintenance device.