JP3663712B2 - Dental air turbine handpiece - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a dental air turbine handpiece for medical use, and more particularly to a dental air turbine handpiece designed to increase torque for rotating a cutting tool.
[0002]
[Prior art and problems to be solved by the invention]
In a conventional dental air turbine handpiece, when performing a dental treatment, for example, when drilling in a patient's teeth, if a considerable load is applied to the rotation of the cutting tool, the torque may be attenuated and the rotational speed may be reduced. It was.
[0003]
[Means for Solving the Problems]
As a result of various studies, the present inventor has solved the above problems with the following configuration.
(1) Dental equipped with a turbine blade fixed to a rotating shaft for holding a cutting tool in a housing, an air supply path for flowing air for rotating the turbine blade, and an exhaust path for discharging the air after rotating the turbine blade In the air turbine handpiece, the inside diameter of the exhaust port at the inlet end of the exhaust path is set larger than the diameter of the inlet port at the tip of the supply path, and the inside of the housing from the supply port to the exhaust port is set. A dental air turbine handpiece characterized in that a circulating air passage is formed by sequentially expanding from an air supply port to an exhaust port side.
(2) The dental air turbine handpiece described in (1) above, wherein the gap between the turbine blade and the upper and lower inner wall surfaces of the chamber is narrowed.
(3) The dental air turbine handpiece according to (1) or (2), wherein the head portion and the neck portion are formed of a synthetic resin.
[0004]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a longitudinal sectional view of a head portion and a neck portion of a dental air turbine handpiece of the present invention.
In the figure, 1 is a head part, 2 is a neck part, 3 is a head housing, 4 is a cap part, 5 is a neck part body, 7 is a chamber, 8 is a turbine blade, 9 is an air supply path, 10 is an exhaust path, 11 Is a bearing part, 12 is a rotating shaft, 13 is a cutting tool, 14 is an inner ring, 15 is an outer ring, 16 is a ball, 17 is a retainer, 18 is an O-ring, 19 is a wave washer, 30 is a vertical gap, 31 is a horizontal gap, 91 is an air supply port.
FIG. 2 is a cross-sectional view taken along the line AA ′ of FIG.
In the figure, 100 is an air passage, and 101 is an exhaust port.
FIG. 3 is an external view of the dental air turbine handpiece of the present invention.
In the figure, 6 is an air supply unit.
[0005]
FIG. 4 is a longitudinal sectional view of a head portion and a neck portion of a conventional dental air turbine handpiece.
In the figure, 1 ′ is a head part, 2 ′ is a neck part, 3 ′ is a head housing, 4 ′ is a cap part, 7 ′ is a chamber, 8 ′ is a turbine blade, 30 ′ is a vertical gap, and 31 ′ is a horizontal gap. is there.
FIG. 5 is a cross-sectional view taken along the line AA ′ of FIG.
In the figure, 100 'is an air passage and 101' is an exhaust port.
FIG. 6 is an external view of a conventional dental air turbine handpiece.
In the figure, 6 is an air supply unit.
[0006]
First, the structure of a conventional dental air turbine handpiece will be described.
As shown in FIG. 4, the head portion 1 ′ includes a rotating shaft 12 having a turbine blade 8 ′ at a peripheral portion in a chamber 7 ′, and a bearing portion that allows the rotating shaft 12 to rotate freely inside the head portion 1 ′. 11 is supported. The head portion 1 'includes a head housing 3' and a cap portion 4 '. A chamber 7' for forming the turbine blade 8 'is formed, and the rotary shaft 12 is rotatably supported. A bearing portion 11 is provided. Further, the shaft of the dental cutting tool 13 is fixedly held on the shaft center portion of the rotary shaft 12.
The bearing portion 12 is constituted by a ball bearing including an inner ring 14, an outer ring 15, a ball 16 and a retainer 17, and an O-ring 18 for a shaft-reception core and a supporting wave are provided on the outer peripheral side portion of the ball bearing. A washer 19 is provided.
When the turbine blade 8 ′ is viewed in the axial direction of the rotary shaft 12, the vertical gap 30 ′ between the upper and lower inner wall surfaces of the turbine blade 8 ′ and the chamber 7 ′ is wide, and the left and right gap 31 ′ between the left and right inner wall surfaces 31 ′ is narrow. It is arranged.
The neck portion 2 ′ includes an air supply passage 9 for supplying pressurized air to a turbine blade 8 ′ in which the neck portion main body 5 is disposed in the chamber 7 ′, an air supply port 91, and an inside of the chamber 7 ′. An exhaust passage 10 ′ for exhausting pressurized air and an exhaust port 101 ′ are configured.
[0007]
Next, the operation of the conventional dental air turbine handpiece will be described.
As shown in FIG. 4, the pressurized air is supplied to an air supply passage 9 provided in the neck portion main body 5 of the neck portion 2 ′, and the compressed air is supplied into the chamber 7 ′ through an air supply port 91. After being guided to the turbine blade 8 ′ and generating a rotational driving force on the rotating shaft 12, the pressurized air is exhausted from the chamber 7 ′ to the exhaust passage 10 through the exhaust port 101 ′. .
As shown in FIG. 5, the flow of pressurized air in the above action makes a U-turn while circling in the direction of the solid line arrow and the dotted line arrow of the air passage 100 ′ around the rotating shaft 12 in the chamber 7 ′. The gas is exhausted to the exhaust passage 10 through the exhaust port 101 ′.
[0008]
In the dental air turbine handpiece having the above configuration, in order to increase the torque of the rotary shaft 12, theoretically, the air supply speed at the air supply port 91 by pressurized air is increased or the unit of pressurized air is increased. It is sufficient to increase the amount of air supply per hour. However, since the dental air turbine handpiece is inserted into the patient's oral cavity and operated, there are restrictions on the size of the head and the exhaust that cannot be exhausted directly into the oral cavity. is there. Therefore, in practice, (1) even if the pressurized air pressure is increased in order to increase the air supply speed, the air supply speed cannot be increased beyond the sound speed as is well known. There is a limit to growth.
(2) Even if the pressurized air pressure is increased to increase the air supply amount,
1) The pressure in the chamber 7 ′ having the above-described structure increases due to the increase in the amount of air supply, and as a result, the air supply speed is decreased.
2) The supplied pressurized air collides with the turbine blade 8 ′, and then mainly passes through the upper and lower gaps 30 ′ (FIG. 4) of the turbine blade 8 ′ in the same direction as the rotating shaft 12 and is indicated by a dotted line arrow shown in FIG. As described above, the circuit 7 circulates in the chamber 7 ′. However, since the circuit speed is lower than the rotational speed of the rotary shaft 12, it acts as a resistor in the chamber 7 ′ and the amount thereof also increases.
(3) Even if the cross-sectional area of the air supply port 91 is increased in order to increase the air supply amount, it acts as a resistor in the chamber 7 'as in the case (2), but the tendency is from the above (2). Is also great. This is because when the cross-sectional area of the air supply port 91 is increased, the compressed air injected from the air supply port 91 rapidly enters the chamber 7 ′ mainly when passing through the upper and lower gaps 30 ′ of the turbine blade 8 ′. As a result of diffusion, the speed decreases, and the resistance action against the rotation of the turbine blade 8 'is increased. For this reason, the transmission efficiency of the supply air energy to the turbine blade 8 ′ of the pressurized air injected from the large air supply port is deteriorated.
Because of the above problems, it has been a difficult task to increase the torque within the constraints.
[0009]
Next, the structure of the dental air turbine handpiece of the present invention will be described. As shown in FIG. 1, the head unit 1 has a rotating shaft 12 having a turbine blade 8 at the periphery in a chamber 7, and the rotating shaft 12 can be rotated inside the head unit 1 via a bearing unit 11. I support it. The head portion 1 includes a head housing 3 and a cap portion 4, and a chamber 7 for arranging the turbine blades 8 is formed, and a bearing portion 11 for rotatably supporting the rotary shaft 12 is formed. Is arranged. Further, the shaft of the cutting tool 13 such as dental cutting is fixedly held on the axial center of the rotating shaft 12.
The bearing portion 12 is constituted by a ball bearing including an inner ring 14, an outer ring 15, a ball 16 and a retainer 17, and an O-ring 18 for a shaft-reception core and a supporting wave are provided on the outer peripheral side portion of the ball bearing. A washer 19 is provided. The turbine blade 8 has a narrow space 30 between the turbine blade 8 and the upper and lower inner wall surfaces of the chamber 7 when viewed from the axial direction of the rotary shaft 12. The diameter of the exhaust port 101 that circulates through the air passage 100 of the third chamber 7 and exhausts the air is set large, and the air passage 100 from the air supply port 91 to the exhaust port 101 is connected to the tip of the air supply passage 9. The exhaust ports 101 are sequentially enlarged from the air supply port 91 so as to coincide with the diameter of the exhaust passage 10.
As shown in FIG. 2 (AA ′ cross-sectional view in FIG. 1), the left and right clearance 31 between the tip of the turbine blade 8 and the left and right outer peripheral inner walls in the chamber is centered on the axis of the cutting tool 13. Starting from 91, the radius of curvature is sequentially increased to reach the exhaust port 101. The neck portion 2 includes an air supply passage 9 for supplying pressurized air to a turbine blade 8 in which the neck portion main body 5 is disposed in the chamber 7, and a pressure in the air supply port 91 and the chamber 7. The exhaust path 10 and the exhaust port 101 for exhausting air are comprised.
The head portion and the neck portion may be formed of a synthetic resin that can be easily molded.
[0010]
Next, the operation of the dental air turbine handpiece of the present invention will be described.
As shown in FIG. 1, the pressurized air is supplied to an air supply passage 9 provided in the neck portion main body 5 of the neck portion 2, and the pressurized air is guided into a chamber 7 through an air supply port 91. After being injected onto the blade 8 and generating a rotational driving force on the rotating shaft 12, pressurized air is exhausted from the chamber 7 through the exhaust port 101 to the exhaust path 10.
As shown in FIG. 2, the flow of pressurized air in the above action makes a U-turn while circulating around the rotation shaft 12 in the chamber 7 and exhausts it through the exhaust port 101 to the exhaust path 10.
In order to increase the torque of the rotary shaft 12 in the above, theoretically, the air supply speed at the air supply port 91 by pressurized air can be increased, or the amount of air supplied per unit time of the pressurized air can be increased. However, since the dental air turbine handpiece is inserted into the oral cavity of the patient and operated, there are restrictions on the size of the head and restrictions that cannot be exhausted directly into the oral cavity. Therefore, in fact, as described above, even if the pressurized air pressure is simply increased in order to increase the air supply speed, the air supply speed cannot be increased beyond the sound speed, and the torque of the rotating shaft 12 increases. There is a limit to torque.
Further, as described above, even if the cross-sectional area of the air supply port 91 is simply increased in order to increase the air supply amount, the efficiency of the supply of air supply energy to the turbine blades 8 is not improved by the action as a resistor in the chamber 7. It is as follows.
[0011]
Therefore, in the present invention, in order to increase the torque, a method is adopted in which the above-described action of the pressurized air flow in the chamber 7 serves as a resistor against the rotation of the turbine blades. That is,
(1) The pressure in the chamber 7 is not increased.
(2) The supplied pressurized air circulates in the chamber 7 in the same direction as the rotating shaft 12 after colliding with the turbine blade 8, but does not slow down the rotating speed compared to the rotating speed of the rotating shaft 12. .
From the above two viewpoints, the following operation is performed.
First, as shown in FIG. 2, the turbine blade 8 has a narrow vertical distance 30 between the upper and lower inner wall surfaces of the turbine blade 8 and the chamber 7 when viewed from the axial direction of the rotating shaft 12. The air gap is prevented from being rapidly diffused by the gap of the vertical interval 30 so that the air supply speed is not lowered.
In addition, the diameter of the exhaust port 101 that circulates in the chamber 7 of the head housing 3 and exhausts air is set larger than the diameter of the air supply port 91 of the air supply path 9, and the air supply port 91 is connected to the exhaust port 101. The leading air passage 100 is sequentially enlarged from the air supply port 91 at the tip of the air supply passage 9 (the cross-sectional area is successively enlarged) so as to coincide with the diameter of the exhaust passage 10 at the exhaust port 101. That is, the left-right gap 31 between the tip of the turbine blade 8 and the left and right outer peripheral inner wall surfaces in the chamber starts from the air supply port 91 and gradually increases the radius of curvature to reach the exhaust port 101.
As shown in FIG. 2, the pressurized air injected from the air supply port 91 rotates around the turbine blade 8 by impact, and then circulates around the interior of the chamber 7 in the direction of the solid arrow of the air passage 100. .
At this time, the volume of the air passage 100 in the chamber 7 gradually increases (increases the cross-sectional area) little by little starting from the air supply port 91, so that the pressurized air does not diffuse suddenly and is supplied. The resistance action which prevents the rotation of the turbine blade 8 by rapidly decreasing the air velocity is prevented.
Further, the exhaust port 101 has the same exhaust volume as that of the exhaust passage, and the flow of pressurized air that circulates inside the chamber 7 during the supply and exhaust processes is sequentially performed in the air passage 100 in the chamber 7. Since it passes through the enlarged portion and reaches the exhaust port having the same diameter as that of the exhaust passage, it can be avoided that the air density sequentially decreases and acts as a resistor that reduces the rotation of the turbine blade 8.
By the above action, the efficiency of the turbine is greatly improved, and the torque of the rotating cutting tool is increased.
[0012]
【The invention's effect】
As described above in detail, according to the dental air turbine handpiece of the present invention, in the conventional air turbine handpiece, a part of the pressurized air acts as a resistor in the chamber to reduce the rotation of the turbine blade. It is possible to improve the efficiency of the turbine and increase the torque by improving the drawbacks.
Therefore, it is possible to prevent a decrease in the rotation speed when a load is applied to the rotation of the cutting tool during dental treatment, and smoother and faster treatment can be performed.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a head portion and a neck portion of a dental air turbine handpiece according to the present invention. FIG. 2 is a sectional view taken along the line AA ′ of FIG. FIG. 4 is a longitudinal sectional view of a head portion and a neck portion of a conventional dental air turbine handpiece. FIG. 5 is a sectional view taken along a line AA ′ in FIG. Flow diagram of blades and pressurized air [Fig. 6] External view of conventional dental air turbine handpiece [Explanation of symbols]
1, 1 ': Head part 2, 2': Neck part 3, 3 ': Head housing 4, 4': Cap part 5: Neck part body 6: Pressurized air supply 7, 7 ': Chamber 8, 8': Turbine blade 9: Air supply path 10: Exhaust path 11: Bearing part 12: Rotating shaft 13: Cutting tool 14: Inner ring 15: Outer ring 16: Ball 17: Retainer 18: O-ring 19: Wave washer 30, 30 ': Vertical gap 31, 31 ′: Left and right gap 91: Air supply port 100, 100 ′: Air passage 101, 101 ′: Exhaust port

Claims (3)

A dental air turbine comprising a turbine blade fixed to a rotating shaft for holding a cutting tool in a housing, an air supply passage for flowing air for rotating the turbine blade, and an exhaust passage for discharging air after the rotation of the turbine blade In the handpiece, air that circulates in the housing from the air supply port to the exhaust port is set with a larger diameter of the exhaust port at the inlet end of the exhaust channel than the diameter of the air supply port at the tip of the supply channel A dental air turbine handpiece characterized in that the passage is formed by sequentially expanding from the air supply port to the exhaust port side. The dental air turbine handpiece according to claim 1, wherein a gap between the turbine blade and the upper and lower inner wall surfaces of the chamber is narrowed. The dental air turbine handpiece according to claim 1 or 2, wherein the head portion and the neck portion are formed of a synthetic resin.

Images