JP2020116371A - Dental turbine handpiece - Google Patents

Abstract

To provide a handpiece that improves an output of a rotor for rotating a cutting tool.SOLUTION: A dental turbine handpiece comprises a grip 10 serving as a part to be gripped by a user, a head connected to a tip of the grip, and a rotor 160 comprised in the head. The rotor comprises a turbine 100 for obtaining rotation torque from supplied air. The head comprises an air supply hole for supplying air to the turbine, and an exhaust hole for exhausting air inside the head. The exhaust hole is formed on a lower side of the air supply hole.SELECTED DRAWING: Figure 3

Description

The present invention relates to a dental turbine handpiece that rotates a cutting tool that cuts teeth using a turbine.

2. Description of the Related Art Conventionally, there is a dental turbine handpiece (hereinafter referred to as a handpiece) that obtains a rotational driving force of a cutting tool for cutting a tooth by using air pressure, in which a torque for rotating the cutting tool is improved. ..
For example, in Patent Document 1, a turbine blade (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 a turbine blade are rotated. In a handpiece having an exhaust passage for discharging the air after being discharged, the diameter of the exhaust outlet at the inlet end of the exhaust passage is set larger than the diameter of the inlet at the tip of the air supply passage, and There is disclosed a handpiece in which an air passage that circulates in the housing from an opening to an exhaust opening is sequentially enlarged from the air supply opening to the exhaust opening side (Patent Document 1).

In such a handpiece, by gradually expanding the air passage from the air supply port to the exhaust port side, the pressure loss inside the head is reduced and the air flow is improved. As a result, the rise in pressure inside the head is reduced, and air can be more efficiently supplied to the inside of the head.

JP, 9-2013370, A

However, in the case of the handpiece described in Patent Document 1, the opening diameter of the exhaust port at the inlet end of the exhaust passage is set to be larger than the diameter of the intake port at the tip of the intake passage, and the exhaust gas is exhausted from the intake port. Since the air passage that circulates inside the housing reaching the port is sequentially expanded from the air supply port to the exhaust port side, there is a problem that the head portion that holds the turbine inside becomes large.

The present invention is for solving the above problems, and an object of the present invention is to provide a handpiece in which the output of a rotor for rotating a cutting tool is improved without increasing the size of the head portion.

In order to solve the problem, a dental turbine handpiece has a grip that is a portion to be gripped by a user, a head connected to a tip of the grip, and a rotor provided in the head, and the rotor is supplied. The head is provided with a turbine that obtains a rotational torque by air, the head has an air supply hole that supplies air to the turbine, and an exhaust hole that exhausts the air inside the head. The exhaust hole may be formed below the air supply hole. ..

According to the present invention, in the dental turbine handpiece, the flow of the air supplied to the inside of the head provided with the turbine is improved, and the output of the rotor can be improved.

(A) Side view of the dental handpiece H according to the first embodiment (b) Perspective view of the dental handpiece H according to the embodiment AA sectional view shown in FIG. BB sectional view shown in FIG. (A) A perspective view of the inside of the turbine chamber with the upper opening opened according to the first embodiment. (b) A perspective view showing a state in which the turbine is arranged in the turbine chamber in the state of (a). 1 is a perspective view of a turbine according to the first embodiment. CC sectional view shown in FIG. 1 is an exploded perspective view of a head case, a nozzle, and an air supply pipe of a dental handpiece according to a first embodiment. DD sectional view shown in FIG. Sectional drawing of the handpiece which concerns on Embodiment 2. EE sectional view shown in FIG.

(Embodiment 1)
The first embodiment will be described with reference to the drawings. In the figure, the head 20 is on the front side, the grip 10 is on the rear side, the direction in which the head 20 and the grip 10 are continuous is the front-rear direction, and the direction orthogonal to this front-rear direction is the left-right direction. The front, rear, left, and right directions are based on a state in which the user holds the grip 10 and uses the handpiece H and sees the handpiece H from the user.

A dental handpiece H (hereinafter, handpiece H) shown in FIGS. 1 and 2 has a turbine 100 that is rotationally driven by supply air (hereinafter, air) supplied from the outside, and a driving force of the turbine 100. Then, the cutting tool 27 for cutting the tooth is rotated and used for dental treatment. Such a handpiece H has a grip 10 and a head 20 connected to the front end of the grip 10.
The air supplied to the handpiece H is adjusted by operating an air adjusting means such as a foot pedal (not shown) provided in the air flow path.

The grip 10 has an outer shell formed of a tubular member, and is a portion that the user holds with his/her hand. A coupling 11 is connected to the rear end of the grip 10.
An air supply pipe 12 that guides the air supplied from the coupling 11 to the head 20 is provided inside the grip 10. Further, the inside of the grip 10 serves as a flow path for the air discharged from the head 20. The exhaust air that has flowed inside the grip 10 flows into the coupling 11.

A cord 11a is connected to the rear end of the coupling 11. The coupling 11 is a portion that serves as a connector for connecting the handpiece H and the cord 11a side. The cord 11a serves as a flow path through which air supplied from an external device to the handpiece H or air exhausted from the head 20 described later flows.
As shown in FIG. 2, the air supply pipe 12 is a pipe-shaped member that forms a flow path through which the air supplied is flown. Air supplied from the cord 11 a is supplied to the head 20 side through the inside of the grip 10 by the air supply pipe 12.
A nozzle 13 is attached to the tip of the air supply pipe 12. The nozzle 13 serves as a portion for injecting the air flowing from the air supply pipe 12 toward the turbine 100 described later.

Next, as shown in FIGS. 2 to 4, the outer shell of the head 20 has a head case 21, a head cap 28, and a push button 22. The head case 21 has a substantially cylindrical portion and a connecting portion 40 that projects rearward from the cylindrical portion, forms a turbine chamber 200 inside, and holds each functional component described later.
The connecting portion 40 is a portion that connects the grip 10 and the head 20. By fitting the grip 10 into the connecting portion 40, the head case 21 and the grip 10 are integrated.

Further, a concave portion 41 that is recessed rearward from the turbine chamber 200 side is formed in a portion of the head case 21 where the connecting portion 40 is located.
Inside the recess 41, an air supply hole 42 and an exhaust hole 43, which are communication holes that connect the inside of the head 20 and the inside of the grip 10, are formed. Inside the air supply hole 42, the air supply pipe 12 and the nozzle 13 attached to the air supply pipe 12 are provided. In addition, the exhaust hole 43 opens toward the inside of the grip 10 that serves as a flow path for exhaust air.

As described above, since the air supply hole 42 is provided with the nozzle 13 which is connected to the air supply pipe 12, and the exhaust hole 43 is opened toward the inside of the grip 10 which is a flow path of exhaust air, the handpiece H Air can be supplied to the inside of the head 20 from the outside, and the air can be discharged from the inside 20 of the head. In particular, the recess 41 serves as an exhaust groove that guides exhaust air from the turbine chamber 200 to the exhaust hole 43.

Next, as shown in FIG. 3, a head cap 28 is provided in the upper opening 20a opening upward of the head case 21 so as to cover the opening. The push button 22 is provided on the upper side of the head cap 28.
A chuck mechanism 26 holding a cutting tool 27 is located below the push button 22. The push button 22 is connected to the chuck mechanism 26. By pushing the push button 22, the chuck mechanism 26 is opened and closed.
The push button 22 thus configured has a function as a release button of the chuck mechanism 26 when the cutting tool 27 is removed. The cutting tool 27 is configured to be attachable to and detachable from the head 20 by opening and closing the chuck mechanism 26.

Inside the head 20, as functional parts, there are a rotary cylinder 24, a bearing 25 (upper bearing 25a, lower bearing 25b), a chuck mechanism 26, a cutting tool 27, a turbine 100, and elements for holding these parts.
The rotary cylinder 24 is a cylindrical member that opens downward. The chuck mechanism 26 is provided inside the rotary cylinder 24 and detachably holds the cutting tool 27. The opening of the rotary cylinder 24 serves as a mounting opening 24a for mounting the cutting tool 27 on the chuck mechanism 26.

As shown in FIGS. 2 and 5, the turbine 100 has a hub 110 and turbine blades 120. The hub 110 is located at the center of rotation of the turbine 100, and a mounting opening 111 that opens in the axial direction is formed at the central portion.
A plurality of turbine blades 120 are provided so as to extend in the radial direction from the periphery of the hub 110. When viewed from the radial direction of the turbine 100, the turbine blade 120 has a concave shape that opens in the direction opposite to the rotation direction of the turbine 100.
The concave shape of the turbine 100 of the present embodiment has a smooth curved shape. For example, it has a shape similar to the roman letter "C" or a shape in which the roman letter "U" is tilted in the direction opposite to the rotation direction. This concave portion serves as an air receiving surface 121 that receives the supplied air.

In such a turbine blade 120, air enters from the upper region to the inside of the concave shape, and the air flows along the air receiving surface 121 to change its direction, and from the lower region to the outside of the concave part. Flows. Note that FIG. 5 schematically shows the position of the nozzle 13 and the flow F of the supply air blown from the nozzle 13.
By thus supplying the air to the turbine blades 120, the pressure of the air acts on the air receiving surface 121 of each turbine blade 120 and becomes the rotational driving force of the turbine 100.
Then, in the turbine 100, by fixing the rotary cylinder 24 to the mounting opening 111, the turbine 100 and the rotary cylinder 24 are integrally rotated by the supplied air. The cutting tool 27, while being held by the chuck mechanism 26, projects downward in the head 20 and rotates together with the rotary cylinder 24. The bearing 25 holds the rotary cylinder 24 rotatably.

Hereinafter, each functional component inside the head 20 will be described.
As shown in FIG. 3, inside the head case 21, an upper bearing 25a and a lower bearing 25b are provided.
An O-ring 25c is provided between the outer ring (outer race) of the upper bearing 25a and the head cap 28 fixed to the head case 21. Similarly, an O-ring 25d is provided between the outer ring of the lower bearing 25b and the head case 21.

Thus, the upper bearing 25a and the lower bearing 25b are provided between the head case 21 side and the O-rings 25c and 25d, respectively, and are fixed to the head case 21 side.
Further, the upper bearing 25a and the lower bearing 25b are located separately on the upper side and the lower side. A turbine chamber 200, which is a space in which the turbine 100 is rotatably positioned, is formed between the upper bearing 25a and the lower bearing 25b that are located apart from each other.
The turbine chamber 200 is a generally cylindrical space matching the shape of the turbine 100. Further, the air supply hole 42 and the exhaust hole 43 are opened toward the turbine chamber 200.

Next, the rotary cylinder 24 is rotatably provided on the bearing 25. That is, the rotary cylinder 24 is provided so as to extend from the upper side of the upper bearing 25a to the lower side 25b of the lower bearing through the inner opening of the inner ring (inner race) of each bearing.
As a result, the rotary cylinder 24 rotates together with the inner ring of the upper bearing 25a and the inner ring of the lower bearing 25b. The mounting opening 24a of the rotary cylinder 24 opens downward.

Next, a chuck mechanism 26 is provided inside the rotary cylinder 24. The chuck mechanism 26 detachably holds the cutting tool 27 inserted through the mounting opening 24a.
When the cutting tool 27 is attached to the chuck mechanism 26, the push button 22 is pressed so that the chuck mechanism 26 can receive the cutting tool 27. That is, the cutting tool 27 can be attached to the head 20.

If the push button 22 is stopped while the cutting tool 27 is inserted into the chuck mechanism 26, the chuck mechanism 26 is closed and the cutting tool 27 is held. As a result, the cutting tool 27 is held by the head 20, and the cutting tool 27 rotates together with the rotary cylinder 24.
When detaching the cutting tool 27 from the chuck mechanism 26, the push button 22 is pushed to release the holding state of the cutting tool 27 of the chuck mechanism 26, and the cutting tool 27 can be detached from the chuck mechanism 26.

Next, the turbine 100 is provided on the outer peripheral portion of the rotary cylinder 24. The turbine 100 has a plurality of turbine blades and can rotate integrally with the rotary cylinder 24. The turbine 100 is located in the turbine chamber 200 inside the head case 21.
Therefore, the turbine 100 rotates in the turbine chamber 200 by blowing the air supplied from the air supply pipe 12 from the nozzle 13 onto the turbine blade 101.

In this way, the rotor 160 is formed by the rotating cylinder 24 and the turbine 100 that have the chuck mechanism 26 therein. The rotor 160 is rotatably provided inside the head case 21. The rotation driving force is generated in the rotor 160 by blowing the air supplied from the air supply holes 42 onto the turbine 100.
As a result, the rotor 160 rotates, and the cutting tool 27 held by the chuck mechanism 26 inside the rotary cylinder 24 also rotates.

Then, the air that has given the rotational driving force to the rotor 160 exits the inside of the head 20 from the exhaust hole 43, passes through the inside of the grip 10 and the coupling 11, and is exhausted to the outside of the handpiece H. In the case of the present embodiment, when the head 20 is viewed from above, the rotor 160 rotates clockwise.
By configuring each part of the handpiece H as described above, it becomes possible to rotate the cutting tool 27 and cut a treatment target such as a tooth.

(Main part of the present embodiment)
Next, with reference to FIGS. 2 and 4, the recess 41 formed inside the head 20, which is a main part of the present embodiment, will be described in detail.
The recess 41 is a rearwardly recessed portion formed on the inner wall on the rear side of the head case 21. Inside the recess 41, an air supply hole 42 and an exhaust hole 43, which are communication holes that connect the inside of the head 20 and the inside of the grip 10, are formed.
Further, the recess 41 is opened so as to spread along the circumference of the turbine chamber 200. In the case of the present embodiment, the recess 41 is formed from the position on the right side of the exhaust hole 43 to the left side of the air supply hole 42. The left and right width of the recess 41 is wider than the left and right width of the connecting portion 40.

Next, the exhaust hole 43 is provided at a position including the central portion of the recess 41 and opens toward the internal space of the grip 10. As a result, the air exhausted from the turbine chamber 200 flows into the exhaust holes 43, reaches the inside of the grip 10, reaches the coupling 11 from the inside of the grip 10, and then reaches the cord 11a. Can be vented to the outside.
The connection surface 44 between the opening edge 41a of the recess 41 to the turbine chamber 200 and the exhaust opening edge 43a of the exhaust hole 43 is formed into a smooth curved surface.

Next, as shown in FIGS. 2 and 8, the air supply hole 42 is a pipe-shaped communication hole that extends substantially parallel to the tangential direction of the rotation circle drawn by the rotation of the turbine 100.
Inside the air supply hole 42, a step portion 42a is formed by making the inner diameter of the rear side larger than the inner diameter of the front side. The air supply hole 42 is provided with the nozzle 13 so as to penetrate the communication hole. That is, the tip of the nozzle 13 is located so as to project from the air supply hole 42 into the recess 41.
The nozzle 13 has a cylindrical shape, and has a shape in which the inner diameter at the tip portion becomes smaller toward the tip. That is, the nozzle 13 has a narrowed shape toward the air outlet 13a from which air is blown. Further, a protrusion 13b is formed on the outer peripheral surface of the nozzle 13 so as to surround the outer peripheral surface.

When the nozzle 13 is inserted into and attached to the air supply hole 42 from the rear side toward the front side, the protruding portion 13 b abuts on the stepped portion 42 a formed inside the air supply hole 42, and the protruding portion 13 b is connected to the air supply hole 42. It is a part that determines the position of the nozzle 13. As a result, the outlet 13a of the nozzle 13 can be located at the correct position with respect to the turbine blade 120.
Further, the protruding portion 13b is a portion that determines the position of the nozzle 13 with respect to the air supply pipe 12 by abutting the tip end opening 12a of the air supply pipe 12 when the nozzle 13 is press-fitted inside the air supply pipe 12. Become.
By mounting the nozzle 13 in this manner, the outlet 13a is located in front of the opening of the exhaust hole 43. Then, inside the recess 41, a space is formed around the nozzle 13.

Here, the positional relationship between the nozzle 13 and the exhaust hole 43 will be described with reference to FIGS.
The nozzle 13 is a member formed in a cylindrical shape, and the exhaust hole 43 is a straight pipe-shaped hole, both of which extend straight.
The nozzle 13 and the exhaust hole 43 extend obliquely with respect to the virtual straight line L extending in the front-rear direction of the handpiece H and extend in the front-rear direction. In the case of the present embodiment, the nozzle 13 and the exhaust hole 43 are inclined so that the front portion is closer to the left side than the rear portion.
The virtual straight line L is, for example, a straight line parallel to the alternate long and short dash line showing the BB cross section. The alternate long and short dash line showing the BB cross section is a line passing through the left and right centers of the handpiece H.

Further, the exhaust hole 34 is arranged close to the side where the nozzle 13 is located. That is, the exhaust hole 34 is arranged so as to extend from the left-right center of the handpiece H to the region on the left side where the nozzle 13 is located. The opening of the exhaust hole 34 is located inside the recess 41 so as to straddle this central position.
Further, the exhaust hole 43 is opened at a substantially central position of the recess 41. The nozzle 13 is provided on the left side of the exhaust hole 43 and in the air supply hole 42 that is open to the upper side in the vertical direction of the recess 41 with the outlet 13a protruding. That is, the outlet 13 a of the nozzle 13 is located on the left side in the recess 41, and is open toward the turbine blade 120 at a position in front of the opening of the exhaust hole 43.
The exhaust hole 43 and the nozzle 13 are provided in the head case 21 in parallel with each other or in a state where the exhaust hole 43 is inclined with respect to the nozzle 13 so that the front side of the exhaust hole 43 approaches the nozzle 13. That is, the exhaust hole 43 is arranged so as to approach the nozzle 13 as it approaches the front side.

The present embodiment configured as described above has the following actions and effects.
First, when the user operates the air adjusting means to start the supply of air to the handpiece H, the supply air flows into the supply pipe 12, and the supply air flows from the outlet 13a of the nozzle 13 toward the turbine 100. Blow out. The air blown out from the nozzle 13 hits the turbine blade 120 and rotates the turbine 100. As a result, the rotor 160 is driven to rotate, and the treatment site can be cut with the rotating cutting tool 27.

Here, the air after hitting the turbine blade 120 and applying the rotational driving force of the turbine 100 is discharged from the inside of the head 20 as follows.

(A) Air that rotationally moves in the turbine chamber 200 together with the turbine 100 The air that rotationally moves in the turbine chamber 200 together with the turbine 100 is sandwiched between the turbine blades 120 that are adjacent to each other in the front-rear direction, as the turbine 100 rotates, It moves along the inner wall of the head case 21.
Then, the air that has rotationally moved together with the turbine 100 enters the inside of the recess 41 from the right side of the recess 41 and flows into the exhaust hole 43. The air flowing into the exhaust hole 43 reaches the coupling 11 from the inside of the grip 10 and is exhausted to the outside of the handpiece H.

As described above, since the recess 41 is configured to reach the right side region away from the nozzle 13 inside the head case 21, the air that rotationally moves in the turbine chamber 200 together with the turbine 100 passes through the exhaust hole 43. It is easy to enter the recess 41 from the position on the right side of the sandwiched portion and flow into the exhaust hole 43.
As a result, the air can be efficiently exhausted from the inside of the turbine chamber 200, so that the flow of air newly blown out from the nozzle 13 to the inside of the turbine chamber 200 is unlikely to be disturbed.

(B) Air bounced from the turbine blade 120 toward the vicinity of the nozzle 13, as in the present embodiment, since the nozzle 13 is positioned so as to project into the recess 41, the outlet 13a should be close to the turbine blade 120. At the same time, the space around which the air bounced from the turbine blade 120 flows is secured around the nozzle 13. That is, the space inside the recess 41 and around the nozzle 13 is a space into which the flow of air rebounding from the turbine blade 120 can enter.

Therefore, the air can be efficiently supplied to the turbine blade 120, and the air that has rebounded toward the nozzle 13 by applying the rotational driving force to the turbine blade 120 flows from the recess 41 around the nozzle 13 to the exhaust hole 43. Can be flushed. As a result, it is possible to mitigate the increase in the pressure of the air around the air outlet 13a and alleviate the difficulty in blowing the air from the air outlet 13a.
In particular, since the recess 41 is formed up to the left side of the nozzle 13, part of the air that has given the rotational driving force to the turbine 100 easily flows into the exhaust hole 43.

Further, since the inner diameter of the nozzle 13 is configured to be smaller toward the tip, the air blown from the nozzle 13 is less likely to diffuse before reaching the turbine blade 120. Thereby, the air can be concentratedly supplied to the region above the air receiving surface 121 of the turbine blade 120.
Then, the air supplied to the turbine blade 120 flows along the air receiving surface 121, turns to a direction away from the air receiving surface 121, and leaves the area below the air receiving surface 121 from the air receiving surface 121. Flow like.

This makes it difficult for the air leaving the air receiving surface 121 and the flow of air newly supplied to the air receiving surface 121 to interfere with each other. In particular, the air supplied toward the upper side of the air receiving surface 121 is less likely to spread due to the shape of the nozzle 13, so it is less likely to interfere with the air flow returning from the lower side of the air receiving surface 121 to the nozzle 13 side.
Therefore, the air can be more efficiently supplied from the nozzle 13 to the turbine 100, and the rotation output of the rotor 160 can be improved.

The nozzle 13 is a component that is attached as a separate component to the air supply hole 42 formed in the head case 21. That is, the head case 21 is composed of independent parts.
With this configuration, since it is not necessary to process a complicated nozzle shape on the head case 21, it is possible to reduce the processing difficulty of the head case 21. In particular, a complicated shape in which the nozzle 13 projects inside the recess 41 of the head case 21 can be formed more easily than when formed by cutting or the like.

Further, since the nozzle 13 is a separate component, the nozzle 13 from the material, the processing time of forming the cutting can be facilitated by using a machine tool. For example, by forming the nozzle 13 into a simple cylindrical shape, it is possible to perform processing that requires precision by cutting, the processing can be easily performed, and productivity is improved.
Further, the shape of the nozzle 13 to be used can be easily selected according to the characteristics of the turbine 100. That is, by appropriately combining the turbines 100 and nozzles of various shapes, it is possible to easily increase the product lineup of handpieces having various characteristics that share the head case 21 and the handle 10.

Further, when the nozzle 13 is formed by machining, it can be performed from the ejection port side of the nozzle 13, so that the degree of freedom in processing can be increased. By increasing the degree of freedom in processing, for example, the shape of the nozzle 13 can be made a Laval nozzle shape that produces a supersonic flow.
Such an air turbine is called an impulse turbine, and the impulse force of air is the source of rotational force. Since this impulse is proportional to the square of the flow velocity, the larger the flow velocity injected from the nozzle 13, the higher the torque and rotation speed, and the higher the efficiency. That is, if the supersonic flow can be obtained, the rotation output of the rotor 160 can be improved.

Further, the nozzle 13 configured as described above is inserted into the air supply hole 42 from the rear toward the front, and the protruding portion 13b is brought into contact with the step portion 42a formed inside the air supply hole 42 to supply the air. It is attached inside the pores 42.
As described above, since the nozzle 13 is mounted so that the position of the nozzle 13 is fixed with respect to the direction of the supply air, the nozzle 13 is pressed against the step portion 42a by the pressure of the supply air, and the supply hole 42 is provided. The nozzle 13 does not shift inside the chamber and does not fall off from the air supply hole 42.

Further, the air flowing through the turbine chamber 200 together with the rotating turbine 100 enters the inside of the recess 41 from the right side of the recess 41 and flows into the exhaust hole 43. As in the present embodiment, since the exhaust holes 43 are arranged closer to the nozzle 13 side, the air flowing into the inside of the recess 41 from the right side of the recess 41 and reaching the exhaust hole 43 reaches the exhaust hole 43. The distance can be increased.
Accordingly, it is possible to suppress the flow of air that directly flows to the exhaust holes 43, suppress the rotation speed of the turbine 100 from becoming too high, and increase the rotational torque.

Furthermore, the exhaust hole 43 is blown out from the nozzle 13 in parallel with the nozzle 13 or by inclining the exhaust hole 43 obliquely with respect to the nozzle 13 so that the front side of the exhaust hole 43 approaches the nozzle 13. The supplied air can be directed to a position where it hits the turbine 100.
As a result, the exhaust holes 43 are arranged closer to the nozzle 13 side, and the air bounced back from the turbine 100 to the nozzle 13 side can be easily guided to the exhaust holes 43.
In particular, for the air flowing while rotating in the turbine chamber 200 together with the turbine 100, the distance from the right side of the recess 41 to the inside of the recess 41 and to the exhaust hole 43 flowing to the exhaust hole 43 becomes long. The flow of air flowing through can be suppressed. Thereby, the air flowing from the turbine 100 to the vicinity of the rebound nozzle 13 can be easily guided to the exhaust hole 43.

By configuring the handpiece H as described above, the air after applying the rotational driving force to the turbine 100 can be efficiently discharged to the outside of the head. As a result, the air supply efficiency of the air supplied into the head is improved, and the rotation output of the rotor 160 that rotates the cutting tool can be improved.

(Embodiment 2)
The second embodiment will be described with reference to FIGS. 9 and 10. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.
FIG. 9 is a sectional view of the handpiece H of the second embodiment. The cross-sectional position of the handpiece in FIG. 9 is the same as AA in FIG. Further, in FIG. 9, the nozzle 13 and the air supply pipe 12 are shown in a state where they are not provided.
FIG. 10 is a sectional view taken along line EE of FIG. In FIG. 10, the rotor 160, the push button 22, the cap 28, other internal structures, and the like are shown only in the head case 21, which is not provided, in order to facilitate the description of the configuration of the second embodiment.

As shown in FIGS. 9 and 10, an exhaust hole 43 is formed in the central portion of the recess 41 inside the recess 41 formed in the head case 21, and the exhaust hole 43 is on the left side and above the recess 41. An air supply hole 42 is formed in the.
Further, in the recess 41, a second exhaust hole 45 is formed below the air supply hole 42. The second exhaust hole 45, like the exhaust hole 43, is a communication hole that connects the inside of the head 20 and the inside of the grip 10. That is, the second exhaust hole 45 is a communication hole for exhausting the exhaust air that rotates the turbine 100 from the turbine chamber 200 to the inside of the grip 10.

As described above, since the second exhaust hole 45 is formed below the air supply hole 42, the air bounced from the turbine blade 120 around the nozzle 13 is discharged from the second exhaust hole 45 to the turbine chamber 200. Can be discharged outside.
As a result, it is possible to mitigate the increase in the pressure of the air around the air outlet 13a and alleviate the difficulty in blowing the air from the air outlet 13a.

In the present embodiment, the second exhaust hole 45 is an independent opening with respect to the exhaust hole 43, but it suffices that the exhaust hole is opened in the lower side portion of the air supply hole 42. That is, the exhaust hole 43 and the second exhaust hole 45 may be one opening.

H Handpiece 10 Grip 11 Coupling 11a Cord 12 Air supply pipe 13 Nozzle 13a Air outlet 20 Head 21 Head case 22 Push button 24 Rotating cylinder 24a Mounting opening 25 Bearing 25a Upper bearing 25b Lower bearing 25c O-ring 26 Chuck mechanism 27 Cutting tool 28 head cap 40 connecting part 41 recess 41a opening edge 42 air supply hole 42a step 43 exhaust hole 43a exhaust opening edge 44 connection surface 100 turbine 110 hub 111 mounting opening 120 turbine blade 121 air receiving surface

Claims (2)

A grip that is a portion to be gripped by a user, a head connected to the tip of the grip, and a rotor provided in the head,
The rotor includes a turbine that obtains a rotation torque by the supplied air,
The head includes an air supply hole that supplies air to the turbine, and an exhaust hole that exhausts air inside the head.
The dental turbine handpiece according to claim 1, wherein the exhaust hole is formed below the air supply hole . The dental turbine handpiece according to claim 1, wherein the air supply hole and the exhaust hole are located inside a recess formed in the head.

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