JPH069575B2 - Dental Air Turbine Hand Piece Rotation Speed Controller - Google Patents

Description

The present invention relates to a dental air turbine for controlling the rotational speed of the air turbine by adjusting the amount of compressed air supplied to the air turbine of a dental air turbine handpiece. The present invention relates to a rotation speed control device for a handpiece.

(Prior Art) Conventionally, a rotation speed control device for a dental air turbine handpiece, which controls the rotation speed of an air turbine of a dental air turbine handpiece, has a flow rate adjusting device arranged between an air source and an air turbine. A dental air turbine handpiece in which a valve is provided with a flow rate adjusting device including a large number of gears and a motor, and the gear of the flow rate adjusting device is rotated by a motor to adjust the valve opening of the flow rate adjusting valve. The amount of compressed air supplied to the air turbine of the dental air turbine was controlled, and thereby the rotational speed of the air turbine of the dental air turbine handpiece was controlled.

(Problems to be Solved by the Invention) However, since such a flow rate adjusting device adjusts the valve opening with a device in which a large number of gears are combined, it is necessary to adjust the air flow rate with little play in the gears. There was a problem in terms of controllability.

Further, since the gear meshing noise is large, the gear is consumed greatly and there is a problem in terms of durability.

In addition, the flow rate adjusting device that meshes many gears in this way adjusts the flow rate because the rotation of the gears stops even if the load applied to the gears is slightly increased because fine dust such as hair is caught in the gears. There was also a problem in terms of reliability of the flow rate control device itself, because it was said that it could not be performed.

(Means for Solving Problems) The present invention has been made in view of the above points, that is,
By the foot pressure of the foot petal, by adjusting the valve opening of the flow rate adjusting valve provided in the middle of the air supply flow path between the air source and the dental air turbine handpiece, by controlling the amount of air flowing to the air turbine, In a rotation speed control device for a dental air turbine handpiece for controlling the rotation speed of an air turbine, an air tank is connected to a pilot port of the flow rate adjusting valve, and a branch is made from an upstream side of the flow rate adjusting valve of the air supply passage. First and second pressure control passages are provided to reach the muffler via the air tank, and an air supply solenoid valve and an air supply throttle valve are provided upstream of the air tank in the first pressure control passage. An exhaust throttle valve and an exhaust solenoid valve are provided on the downstream side, and a rapid air supply solenoid valve is provided on the upstream side of the air tank in the second pressure control flow path and a rapid supply solenoid valve is provided on the downstream side. An air solenoid valve is provided, and a variable resistor for detecting the stepped amount of the foot petal and setting a target value of the rotational speed of the air turbine is provided, and the target value, the flow rate adjusting valve, and the dental A solenoid valve control device for controlling opening / closing operations of the various solenoid valves by comparing with a measurement value measured by a pressure sensor provided in the middle of the air supply passage between the air turbine handpieces. Is a rotation speed control device for a dental air turbine handpiece.

(Embodiment) An embodiment of the rotational speed control device for a dental air turbine handpiece of the present invention will be specifically described below with reference to the drawings.

1 is a circuit diagram when compressed air is supplied into an air tank in a rotation speed control device for a dental air turbine handpiece according to an embodiment of the present invention to rotate an air turbine at a high speed, and FIG. 2 is FIG. FIG. 3 is a circuit diagram when the compressed air in the air tank of the rotation speed control device is discharged to rotate the air turbine at a low speed, and FIG. 3 is a block diagram of the solenoid valve control circuit of the control device of the present invention.

As shown in FIG. 1, the rotational speed control device for a dental air turbine handpiece according to the present invention is mainly provided in the middle of an air supply passage 4 communicating with an air turbine 3 of a dental air turbine handpiece 2 from an air source 1. A flow rate adjusting valve 6 provided with the air tank 5 is arranged so that the valve opening degree is adjusted by the air pressure in the air tank 5, and a first branching branch is made from the upstream side of the flow rate adjusting valve 6 in the air supply flow path 4. And solenoid valves 8a, 8b, 8c, 8 for controlling the supply or discharge of compressed air to the air tank 5 in the middle of the second pressure control flow paths 7a, 7b.
d, the solenoid valve 8a, 8b, 8c, 8d detects the stepped amount of the foot petal and sets the target value of the rotational speed of the air turbine 3 and the target value of the variable resistor 9 and the flow rate adjustment. Solenoid valve control circuit for controlling flow rate by comparing and opening / closing measurement values measured by a pressure sensor 10 arranged in the air supply flow path 4 between the valve 6 and the dental air turbine handpiece 2. 11 and 11.

As shown in FIG. 1, the flow path of compressed air in the rotation speed control device for a dental air turbine handpiece according to the present invention is mainly an air supply flow path 4 leading from the air source 1 to the air turbine 3 of the dental handpiece 2. And a first pressure control flow path 7a branching from the trifurcated path 12 upstream of the air supply flow path 4 to the muffler 13 via the air tank 5, and an upstream side of the first pressure control flow path 7a. And a second pressure control flow path 7b which branches from the three-way passage 14 to reach the muffler 13 via the air tank 5.

A flow rate adjusting valve 6 with a pilot, which is additionally provided with an air tank 5, is arranged in the middle of the air supply flow path 4, and the flow rate of the flow rate adjusting valve 6 with a pilot flows to the dental air turbine handpiece 2. The amount of compressed air is controlled.

Further, the first pressure control flow path 7 a branches from a three-way passage 12 provided upstream of the flow rate adjusting valve 6 of the air supply flow path 4 and is attached to the pilot-equipped flow rate adjusting valve 6 of the air supply flow path 4. After passing through the four-way passage 15 that is connected to the installed air tank 5 by the connection passage 7d, the silencer 13 is reached.
An air supply solenoid valve 8a for controlling air supply to the air tank 5 is provided upstream of the four-way passage 15 in the middle of the first pressure control flow path 7a, and compressed air in the air tank 5 is provided downstream thereof. An exhaust electromagnetic valve 8b for controlling the exhaust of is provided. Further, a supply flow rate adjusting valve 16a is provided between the four-way passage 15 and the air supply solenoid valve 8a, and an exhaust flow rate adjusting valve 16b is provided between the four-way passage 15 and the exhaust solenoid valve 8b. Is provided.

The flow rate control valve 6 with a pilot of the air supply passage 4 automatically adjusts the valve opening degree when the pressing force changes depending on the height of the air pressure in the air tank 5. For example,
When the air pressure in the air tank 5 is high, the pressing force becomes large and the valve opening degree of the pilot-equipped flow rate adjusting valve 6 becomes large, so that the flow rate of compressed air to the air turbine 3 of the dental handpiece 2 increases. To do. Further, when the air pressure in the air tank 5 is low, the pressing force becomes small and the valve opening degree of the pilot-equipped flow rate adjusting valve 6 becomes small or closed, so that the compressed air to the air turbine 3 of the dental handpiece 2 is compressed. Reduce or stop the flow rate of.

Therefore, in order to increase the air flow rate to the air turbine 3 of the dental handpiece 2, as shown in FIG. 1, the air supply solenoid valve 8a is opened, the exhaust solenoid valve 8b is closed, and the inside of the air tank 5 is closed. Compressed air is introduced into the air tank 5
This is performed by increasing the internal air pressure, thereby opening the flow rate adjusting valve 6 and increasing the air flow rate of the air supply passage 4 flowing to the air turbine 3.

Further, in order to reduce the flow rate of the compressed air of the air turbine 3 of the dental handpiece 2, as shown in FIG.
Close the air supply solenoid valve 8a, open the exhaust solenoid valve 8b,
The compressed air in the air tank 5 is discharged from the silencer 13 to the atmosphere, and the air pressure in the air tank 5 is reduced, thereby reducing the valve opening of the flow rate adjusting valve 6 and flowing into the air turbine 3. This is done by reducing the air flow rate of.

However, since it is difficult to adjust a minute air flow rate only with these solenoid valves 8a and 8b, the air supply throttle valve 16a and the exhaust air throttle valve 16a disposed on the air tank 5 side of the air supply solenoid valve 8a and the exhaust solenoid valve 8b are used. By adjusting the throttle valve 16b to an appropriate opening degree in advance, even if the solenoid valves 8a and 8b are opened and closed, the air pressure in the air tank 5 does not suddenly rise or drop, and a small amount of air flow rate is adjusted. It becomes possible.

However, the first pressure control flow path in which the air supply throttle valve 16a and the exhaust air throttle valve 16b are arranged cannot be used in an emergency by simply opening and closing the air supply solenoid valve 8a and the exhaust solenoid valve 8b. Therefore, the air pressure in the air tank 5 cannot be rapidly increased or decreased.

Therefore, in addition to the first pressure control flow path 7a,
There is provided a second pressure control flow path 7b that branches from the three-way path 14 on the upstream side of the pressure control flow path 7a to the rear silencer 13 via the three-way path 17 that leads to the air tank 5. The other one of the three-way passages 17 provided in the middle of the second pressure control passage 7b is connected to one of the four-way passages 15 provided in the middle of the pressure control passage 7a by a connecting passage 7c. . A solenoid valve 8c for rapid air supply is provided on the upstream side of the three-way passage 17.
However, the rapid exhaust solenoid valves 8d are respectively provided on the downstream side.

Thus, when the dental air turbine handpiece 2 is started or when the flow rate is significantly increased, the air supply solenoid valve 8 is used.
The compressed air can be rapidly supplied into the air tank 5 by fully opening the rapid air supply solenoid valve 8c together with a. Further, when the dental air turbine handpiece 2 is stopped or the flow rate is significantly reduced, the rapid exhaust electromagnetic valve 8d together with the exhaust electromagnetic valve 8b can be fully opened to rapidly exhaust the compressed air.

As a result, these rapid air supply valve 8c and rapid exhaust valve 8
The air pressure in the air tank 5 can be rapidly increased or decreased by opening and closing d, and the rapid air supply valve 8c and the rapid exhaust valve 8d are operated in the case of a large change in the flow rate or in an emergency. You can

The air supply solenoid valve 8a, the exhaust solenoid valve 8b, the rapid air supply solenoid valve 8c and the rapid exhaust solenoid valve 8d are electrically connected to the solenoid valve control device 11 by wirings 18a, 18b, 18c and 18d, respectively. It is connected. Then, the opening / closing operation of the solenoid valves 8a, 8b, 8c, 8d is
The amount of compressed air supplied to and exhausted from the air tank 5 is adjusted by being controlled by the electric signal transmitted from the solenoid valve control device 11.

The solenoid valve control device 11 is additionally provided with a variable resistor 9 for detecting the stepping amount of the foot petal and setting a target value of the air turbine rotation speed. By detecting
Set the target value of the air turbine speed.

Further, the solenoid valve control device 11 includes a pressure sensor 10
This pressure sensor 10 measures the air pressure in the air supply passage 4 between the flow rate adjusting valve 6 in the air supply passage 4 and the air turbine 3 in the dental handpiece 2, and the wiring 19 The measured value of the pressure sensor 10 is transmitted to the solenoid valve control device 11 including the pressure detection circuit 21 for converting the measured value into the comparative value by an electric signal.

As shown in FIG. 3, the solenoid valve control device 11 mainly includes a pressure setting circuit 20 for setting a target value of the air turbine rotation speed, and a pressure detection circuit 21 for converting the pressure sensor 10 into a measured value. , A set pressure comparison circuit 22 for comparing signals transmitted from these circuits, a first control circuit 23a and a second control circuit 23b which are switched according to the value of the comparison value, and the solenoid valves 8a, 8b, 8c, 8d.
Solenoid valve opening / closing circuits 24a, 24b, 24c for opening and closing
It is composed of 24d.

To specifically describe the control of the solenoid valve control device 11, the stepping amount of the foot petal is detected by the variable resistor 9, the detected value is set as a target value by the pressure setting circuit 20, and the pressure sensor 10 is separately provided. The measured air pressure between the flow control valve 6 and the air turbine 3 of the dental handpiece 2 is converted into a comparison value by the pressure detection circuit 21, and the target value and this comparison value are compared with the set pressure comparison circuit 2
2 and if there is a deviation, the solenoid valve 8a,
8b, 8c, 8d open / close operation command is transmitted.

For example, when the target value at the time of starting the operation >> the comparison value (initial value = 0), the target value set in the pressure setting circuit 20 is first compared with the comparison value in the set pressure comparison circuit 22, and the When the polarity of the deviation (target value-comparison value) is positive, the set pressure comparison circuit 22 transmits an operation command to the first control circuit 23a and a stop command to the second control circuit 23b. Then, the deviation is compared with a preset value in the first control circuit 23a, and the deviation is compared with the first set value.
When it is larger than the set value of the control circuit 23a, the first control circuit 23a transmits an operation command to the air supply solenoid valve operating unit 24a and the rapid air supply solenoid valve operating unit 24c, and the air supply solenoid valve 8a. And the rapid air supply solenoid valve 8c is opened.

As a result, the compressed air is introduced into the air tank 5, and when the pressure in the air tank 5 is rapidly increased, the flow rate control valve 6 opens, and the compressed air is injected into the air turbine 3 to rotate the air turbine 3 at high speed.

At this time, the measured value from the pressure sensor 10 is used as the pressure detection circuit
When the polarity of the deviation (target value-comparison value) is positive, the set pressure comparison circuit 22 converts the comparison value into a successive comparison value by 1 and compares the comparison value with the target value by the set pressure comparison circuit 22. Similarly to the above, the set pressure comparison circuit 2
The operation command is transmitted from 2 to the first control circuit 23a. When the deviation is smaller than the set value of the first control circuit 23a, the first control circuit 23a transmits an operation command to the rapid air supply solenoid valve operation unit 24c, and the rapid air supply solenoid valve 8c.
Close. When the deviation is larger than the set value of the first control circuit 23a, the rapid air supply solenoid valve 8c remains open. Further, in the same manner as described above, the set pressure comparison circuit 22 compares the target value with the comparison value, and when the polarity of the deviation (target value-comparison value) becomes negative, the set pressure comparison circuit 2
2 issues a stop command to the first control circuit 23a, and
The operation command is transmitted to the control circuit 23b. And the first
Control circuit 23a closes the rapid air supply solenoid valve 8c by the rapid air supply solenoid valve operating unit 24c, and the second control circuit 23b sets the deviation (| target value-comparative value |) to a preset value. In comparison, when the deviation is smaller than the set value of the second control circuit 23b, the second control circuit 23b causes the rapid exhaust solenoid valve operating unit 24d to close the rapid exhaust solenoid valve 8d and the exhaust solenoid valve 8b. Leave open.

As a result, the flow rate adjusting valve 6 is controlled by adjusting the pressure in the air tank 5 to a constant state, and the compressed air supplied to the air turbine 3 is adjusted to a constant state so that the air turbine 3 is controlled.
The rotation speed of is controlled to a constant state.

And comparison value when work is stopped or when the flow rate is changed drastically >>
In the case of the target value (= 0), the set pressure comparator 22 issues a stop command to the first control circuit 23a in the same manner as described above.
In addition, an operation command is transmitted to the second control circuit 23b, the air supply solenoid valve 8a is closed by the first control 23a, and the rapid exhaust solenoid valve 8b is opened by the second control circuit 23b.

As a result, the compressed air in the air tank 5 is released into the atmosphere, the flow rate adjusting valve 6 is closed, and the supply of compressed air is stopped.

As described above, the solenoid valve control device 11 sets the rotational speed of the air turbine 3 (target value) to control the rotational speed of the air turbine 3.
The measured value of 1 is converted into a successive comparison value by the pressure detection circuit 21, and the comparison value is automatically converged to the target value by comparing and controlling the set value comparison circuit 22 with the target value. The rotation speed can be controlled stably.

By connecting the air tank 5 and the air supply / exhaust throttle valves 16a, 16b forming an integrating circuit to the pilot port of the flow rate adjusting valve 6, a rapid change in compressed air due to the opening / closing operation of the air supply / exhaust solenoid valves 8a, 8b. Is alleviated to stabilize the control by the flow rate adjusting valve 6.

The air supply amount and the air discharge amount of the air tank 5 are controlled by a timer or the like in addition to adjusting the opening / closing frequency of both solenoid valves 8a and 8b and the opening degree of the throttle valves 16a and 16b. It can also be adjusted by doing.

(Effects of the Invention) As described in detail in the above examples, the rotation speed control device for a dental air turbine handpiece of the present invention is provided with a flow rate adjusting valve that is opened and closed by the air pressure of the air tank in the air supply passage, and An electromagnetic valve that controls the supply and exhaust of compressed air is provided in the flow path that leads to the air tank, and this electromagnetic valve is opened and closed by a solenoid valve control device to supply and exhaust compressed air to and from the air tank. Adjust the air pressure.

Since the flow rate of the compressed air flowing through the air turbine can be adjusted by adjusting the valve opening degree of the flow rate adjusting valve by the air pressure of the air tank in this way, the valve opening degree as in the conventional flow rate adjusting device can be adjusted. Since it is not adjusted by the gear device attached to the valve, it is easy to make fine adjustments to the flow rate of compressed air, there is no meshing noise of the gear that opens and closes the valve, and the rotation of the gear stops with a slight load. Such a problem does not occur, and there is no problem in terms of adjustability, durability and reliability.

Therefore, since the flow rate of the compressed air can be finely adjusted, the flow rate can be slightly changed, and the flow rate adjusting device in the device of the present invention is excellent.

Then, even with a sudden change in the flow rate in the pressure control flow path, the change in pressure is alleviated, and the air pressure supplied to the air turbine handpiece can be stably maintained.

[Brief description of drawings]

1 is a circuit diagram when compressed air is supplied into an air tank in a rotation speed control device for a dental air turbine handpiece according to an embodiment of the present invention to rotate an air turbine at a high speed, and FIG. 2 is FIG. FIG. 3 is a circuit diagram when the compressed air in the air tank of the rotation speed control device is exhausted to rotate the air turbine at a low speed, and FIG. 3 is a block diagram of a solenoid valve control circuit of the control device. 1: Air Source 2: Dental Air Turbine Handpiece 3: Air Turbine 4: Air Supply Flow Path 5: Air Tank, 6: Flow Control Valves 7a, 7b: Pressure Control Flow Path, 8a: Air Supply Solenoid Valve 8b: Solenoid valve for exhaust, 8c: Solenoid valve for rapid air supply 8d: Solenoid valve for rapid exhaust 9: Variable resistor, 10: Pressure sensor 11: Solenoid valve control device 12, 14, 17: Three-way passage 13: Silencer, 15: Four-way passage 16a: Air supply throttle valve 16b: Exhaust throttle valve 18a, 18b, 18c, 18d: Wiring 19: Wiring, 20: Pressure setting circuit 21: Pressure detection circuit, 22: Set pressure comparison circuit 23a: First Control circuit, 23b: second control circuit 24a: solenoid valve operating portion for air supply 24b: solenoid valve operating portion for exhaust 24c: solenoid valve operating portion for rapid air supply 24d: solenoid valve operating portion for rapid exhaust

Claims (1)

[Claims] 1. A foot opening pressure of a flow rate adjusting valve provided in the middle of an air supply passage between an air source and a dental air turbine handpiece is adjusted by the foot pedal pressure to control the amount of air flowing to the air turbine. By controlling, in a rotation speed control device for a dental air turbine handpiece for controlling the rotation speed of the air turbine, an air tank is connected to the pilot port of the flow rate adjusting valve, and the flow rate adjusting valve of the air supply passage is controlled. First and second pressure control flow paths branching from the upstream side to reach the muffler via the air tank are provided, and an air supply solenoid valve and air supply are provided on the upstream side of the air tank in the first pressure control flow path. Throttle valve, and an exhaust throttle valve and an exhaust solenoid valve on the downstream side, and a rapid air supply solenoid valve on the upstream side of the air tank in the second pressure control flow path, and a down valve. The side by disposing an electromagnetic valve for quick exhaust, provided a variable resistor for setting the rotational speed of the target value of the air turbine and further detects the depression amount of the Futopetaru,
Then, the target value and the measured value measured by the pressure sensor provided in the middle of the air supply passage between the flow rate adjusting valve and the dental air turbine handpiece are compared to open and close the various solenoid valves. And a solenoid valve control device for controlling the rotation speed of the dental air turbine handpiece.