CONTROL DEVICE OF DENTAL HANDPIECE

• US 20140134565A1
• Filed: 05/23/2012
• Published: 05/15/2014
• Est. Priority Date: 05/27/2011
• Status: Active Grant

• Current Assignee: Nakanishi Inc.
• Original Assignee: Nakanishi Inc.
• Inventors: Kunisada, Makoto
• Granted Patent: US 9,186,226 B2
• Time in Patent Office: Days
• US Class Current: 433/27
• CPC Class Codes: A61C 1/0007 Control devices or systems fluid temperature control in air and water supply systems of dental machines or apparatus A61C1/0069
• CPC Class Codes: A61C 1/0015 Electrical systems
• CPC Class Codes: A61C 1/003 Control of rotation of instrument
• CPC Class Codes: A61C 1/06 with electric drive
• CPC Class Codes: A61C 1/12 Angle hand-pieces
• CPC Class Codes: A61C 19/04 Measuring instruments specially adapted for dentistry A61C5/44 takes precedence; testing vitality of teeth A61B5/0534; radiation diagnosis specially adapted for dentistry A61B6/51
• CPC Class Codes: A61C 3/02 Tooth drilling or cutting instruments; Instruments acting like a sandblast machine

Abstract

An object is to provide a control device of a dental handpiece that is able to prevent giving a shock to the operator having the dental handpiece and the patient of treatment subject and also that is able to reduce the load onto the motor and to suppress heat generation thereof. The rotational direction of a motor 20 of a dental handpiece is switched at every certain time. At this time, before the rotational direction of the motor 20 is switched through switching of a relay 17, voltage to be applied to the motor 20 is reduced. It is thereby prevented that a large current flows into the motor 20 when the relay 17 is switched, and also that a large rotation torque is applied to a cutting tool rotationally driven by the motor 20.

Claims

1. A control device of a dental handpiece, comprising:

a voltage application portion for applying voltage to a motor for rotating a cutting tool mounted to the dental handpiece, the motor being built in the dental handpiece;

a rotational direction switching portion for switching a rotational direction of the motor by switching a polarity of voltage, which is applied to the motor by the voltage application portion; and

a control portion for controlling a magnitude of the voltage applied by the voltage application portion,

wherein the control portion obliquely decreases voltage in advance of switching of voltage polarity, which is conducted by the rotational direction switching portion, the voltage being applied to the motor by the voltage application portion.

2. The control device of a dental handpiece according to claim 1, wherein voltage to be applied to the motor from the voltage application portion is obliquely increased after the voltage polarity has been switched.

3. The control device of a dental handpiece according to claim 1, wherein the control portion controls so that the rotational direction switching portion carries out switching of the voltage polarity at every lapse of a predetermined certain time.

4. The control device of a dental handpiece according to claim 1, further comprising a sensor for detecting a rotation angle of the motor,

wherein the control portion controls so that, when a rotation angle of the motor detected by the sensor reaches a predetermined certain angle, the rotational direction switching portion carries out switching of the voltage polarity.

5. The control device of a dental handpiece according to claim 2, wherein the control portion has a function of calibrating a rate RT, which increases or decreases voltage to be applied to the motor from the voltage application portion.

6. The control device of a dental handpiece according to claim 5, wherein the control portion performs variable control of the rate RT.

7. The control device of a dental handpiece according to claim 6, wherein the control portion performs variable control of the rate RT depending on a rotation speed of the motor.

8. The control device of a dental handpiece according to claim 6, wherein the control portion performs variable control of the rate RT depending on a load torque applied to the motor.

9. The control device of a dental handpiece according to claim 6, wherein a plurality of rates causing voltage to decrease or increase, the voltage being applied to the motor from the voltage application portion, and the control portion performs variable control of the rate RT depending on a rate selected out of the plurality of rates.

10. The control device of a dental handpiece according to claim 6, wherein the control portion performs variable control of the rate RT depending on a distance from an apic of treatment subject to the cutting tool.

11. The control device of a dental handpiece according to claim 1, wherein the control portion performs variable control of a back-and-forth time T of the motor depending on an extent of heat generation of the motor, the back-and-forth time T being specified by a following equation 2.

T=Tcw+Tstop+Tccw 

 

Equation 2

Back-and-forth time T of a motor;

Time required for forward rotation and reverse rotation of the motor

Tcw;

Time required for forward rotation of the motor

Tccw;

Time required for reverse rotation of the motor

Tstop;

Standing time of the motor required when the rotational direction is switched from forward rotation to reverse rotation

12. A control device of a dental handpiece, comprising:

a voltage application portion for applying voltage to a motor for rotating a cutting tool mounted to the dental handpiece, the motor being built in the dental handpiece;

a rotational direction switching portion for switching a rotational direction of the motor by switching a polarity of voltage, which is applied to the motor by the voltage application portion; and

a control portion for controlling a magnitude of the voltage applied by the voltage application portion,

wherein the control portion obliquely decreases voltage in advance of switching of voltage polarity, which is conducted by the rotational direction switching portion, the voltage being applied to the motor by the voltage application portion,

wherein voltage to be applied to the motor from the voltage application portion is obliquely increased after the voltage polarity has been switched, and

wherein the control portion controls so that the rotational direction switching portion carries out switching of the voltage polarity at every lapse of a predetermined certain time.

13. A control device of a dental handpiece, comprising:

a voltage application portion for applying voltage to a motor for rotating a cutting tool mounted to the dental handpiece, the motor being built in the dental handpiece;

a rotational direction switching portion for switching a rotational direction of the motor by switching a polarity of voltage, which is applied to the motor by the voltage application portion;

a control portion for controlling a magnitude of the voltage applied by the voltage application portion; and

a sensor for detecting a rotation angle of the motor,

wherein the control portion obliquely decreases voltage in advance of switching of voltage polarity, which is conducted by the rotational direction switching portion, the voltage being applied to the motor by the voltage application portion,

wherein voltage to be applied to the motor from the voltage application portion is obliquely increased after the voltage polarity has been switched, and

wherein the control portion controls so that, when a rotation angle of the motor detected by the sensor reaches a predetermined certain angle, the rotational direction switching portion carries out switching of the voltage polarity.