Dental Handpiece

Abstract

The present invention provides an impeller-type dental handpiece that can improve the rotation efficiency of the impeller and, in turn, the cutting efficiency. The deviation in the orientation of an air supply hole O1, which is a communication hole for an air supply passage (121) to the internal space of the housing (11), and an exhaust hole O2, which is a communication hole for an exhaust passage (122) to the internal space of the housing (11), is within the range of 35° to 155°, based on the central axis of the housing (11).

Description

[Technical Field]

[0001] The present invention relates to an impeller-type dental handpiece. [Background technology]

[0002] The present inventor has proposed a dental handpiece that includes a housing with an impeller for rotating a tooth-cutting tool, and a handle-side housing attached to the housing that incorporates an air supply passage for the impeller (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-162078 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional dental handpieces have room for improvement in the rotation efficiency of the impeller.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an impeller-type dental handpiece that can improve the rotational efficiency of the impeller and, in turn, the cutting efficiency. [Means for solving the problem]

[0006] The dental handpiece of the present invention comprises: Housing and an impeller disposed in the interior space of the housing so as to be rotatable about an axis for rotating a tooth cutting tool; a handle-side housing attached to the housing and having an air supply passage and an air exhaust passage for the impeller, The deviation of the orientation of an air intake communicating hole, which is a communicating hole of the air intake passage to the internal space of the housing, and an exhaust communicating hole, which is a communicating hole of the exhaust passage to the internal space of the housing, based on the central axis of the housing, is within a range of 35° to 155°. 、 When viewed from the central axis of the internal space of the housing, the air intake communication hole is oriented at a first azimuth angle in a clockwise direction with respect to a reference axis that extends perpendicularly to the central axis along the longitudinal direction of the handle-side housing, and the exhaust communication hole is oriented at a second azimuth angle in a counterclockwise direction that is larger than the first azimuth angle, The distance between the exhaust communication hole and the rotation area of ​​the impeller is configured to be greater than the distance between the air supply communication hole and the rotation area of ​​the impeller. . [Brief explanation of the drawings]

[0007] [Figure 1] 1 is an explanatory diagram illustrating the configuration of a dental handpiece according to an embodiment of the present invention; [Figure 2] FIG. 2 is a schematic plan view of an impeller of a dental handpiece. [Figure 3] 1 is a configuration explanatory diagram of a main part of a dental handpiece according to a first embodiment of the present invention; [Figure 4] FIG. 4 is a configuration explanatory diagram of a main part of a dental handpiece according to a second embodiment of the present invention. [Figure 5] FIG. 10 is a configuration explanatory diagram of a main part of a dental handpiece according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] (composition) An impeller-type dental handpiece 1 according to one embodiment of the present invention, shown in FIG. 1, includes a housing 11 having a generally cylindrical internal space, an impeller 2 disposed in the internal space (turbine chamber) of the housing 11 for rotating a tooth-cutting tool 4, and a handle-side housing 12 attached to the housing 11 and provided with an air supply passage 121 and an exhaust passage 122 for the impeller 2. A three-dimensional Cartesian coordinate system (x, y, z) is used to understand the relative positions of the components of the handpiece 1. The handle-side housing 12 is designed to have an appropriate shape and size for easy gripping by a practitioner such as a dentist. As shown in FIG. 1, an air supply conduit 101 is connected to the air supply passage 121, and an exhaust conduit 102 is connected to the exhaust passage 122.

[0009] 1, the height position (position in the z direction) of the communication hole (air supply hole O1) of the air supply passage 121 relative to the internal space (turbine chamber) of the housing 11 is higher than the height position of the communication hole (exhaust hole O2) of the exhaust passage 122 relative to the internal space of the housing 11. The height positions of the two communication holes may be the same, or the up-down relationship may be reversed. The shapes of the air supply hole O1 and the exhaust hole O2 (the cross-sectional shapes of the air supply passage 121 and the exhaust passage 122) may be generally circular, or may be various shapes such as generally elliptical, generally rectangular, generally trapezoidal, or generally hexagonal.

[0010] As shown in Fig. 1, the handle side housing 12 is provided with an air supply passage 121 and an exhaust passage 122 for the impeller 2, as well as a water supply passage 124 that communicates with the external space of the handle side housing 12 and opens downwardly from the housing 11. As shown in Fig. 3, a water supply conduit 104 is connected to the water supply passage 124, and the exhaust passage 122 is arranged to merge with the water supply passage 124. The water supply passage 124 may be omitted.

[0011] The upper part of the housing 11 may be configured as a cover member, and opening or removing the cover member allows access to the internal space of the housing 11, thereby enabling replacement of the impeller 2.

[0012] 2, the impeller 2 includes a rotor 220 that is fixed to or detachably attached to a substantially cylindrical shaft 20, and P (P=12 in this embodiment) blades 222 that extend radially from the rotor 220. As shown in Fig. 2, each blade 222 is formed in the shape of a substantially isosceles triangular prism that extends in the direction of the rotation axis of the impeller 2 (z direction).

[0013] As shown in Fig. 1, shaft 20 is rotatably held relative to housing 11 via upper ball bearing 111 and lower ball bearing 112 at upper shaft portion 201 and lower shaft portion 202, respectively. A cutting tool 4 is fixed to lower shaft portion 202 coaxially with shaft 20. Cutting tool 4 may be detachably attached to lower shaft portion 202, for example, by fitting an upper portion of cutting tool 4 into a hole at the bottom of lower shaft portion 202. As shown in Fig. 1, at least a portion of cutting tool 4 including file portion 40 protrudes downward from housing 11 through through-hole 114 provided at the bottom of housing 11.

[0014] The number of blades 222 constituting the impeller 2 may be any plural number such as 12, 4, 6, 8, 10, 14, 16, 18, or 24. The shape of each blade 222 may be modified in various ways. For example, each blade 222 may be formed in a substantially rectangular columnar shape, a substantially elliptical columnar shape, or a substantially arc columnar shape (a columnar shape that protrudes in the radial direction so as to curve in the circumferential direction) whose axial direction is the direction of the rotation axis of the impeller 2. Each blade 222 may be formed in a substantially wing shape that extends in the radial direction and is inclined with respect to the direction of the rotation axis of the impeller 2.

[0015] The impeller 2 may be made of a light metal such as aluminum (specific gravity 2.7) or various aluminum alloys (specific gravity 2.6 to 2.8) such as duralumin (specific gravity 2.8). The blades 22 may be made of ceramics such as forsterite (2MgO·SiO2) (specific gravity 3.0), silicon carbide (SiC) (specific gravity 3.16), silicon nitride (Si3P4) (specific gravity 3.3), aluminum nitride (AlP) (specific gravity 3.4), alumina (Al2O3) (specific gravity 3.8), yttria (Y2O3) (specific gravity 4.9), or zirconia (ZrO2) (specific gravity 6.0), as well as metal composite materials such as cermet (TiC·TiP) (specific gravity 6.0). The impeller 2 may be made of heavy metals such as iron (specific gravity 7.9), nickel (specific gravity 8.8), copper (specific gravity 8.9), or alloys thereof. If the impeller 2 is made of chromium or lead, it is preferable that the entire impeller be plated with a harmless metal such as silver or nickel. Impellers 2 having complex shapes can be produced using a three-dimensional printer using raw material powder and / or laser processing of the raw material.

[0016] (First embodiment) 3 shows a first embodiment of the arrangement of the air supply passage 121 and the exhaust passage 122 relative to the internal space of the housing 11. The internal space of the housing 11 is a substantially cylindrical space with the rotation axis of the impeller 2 as its central axis (parallel to the z-axis). An azimuth angle is defined with respect to the central axis of the internal space of the housing 11 as the reference, based on a reference axis C that extends from the central axis of the internal space of the housing 11 in the +x direction (the longitudinal direction of the handle-side housing 12).

[0017] 3, the communication hole (air supply hole O1) of the air supply passage 121 is positioned at a first azimuth angle θ1 in the clockwise direction around the reference axis C when viewed from the central axis of the interior space of the housing 11, and the azimuth angle range is θ1-Δθ1 to θ1+Δθ1. The first azimuth angle θ1 is, for example, in the range of 15° to 30°. "Δθ1" is, for example, 2° to 2.5°. The angle φ1 formed by the air supply direction from the air supply passage 121 to the interior space of the housing 11 (the extension direction of the air supply passage 121 near the air supply hole O1) and the tangent direction of the interior space is, for example, in the range of 0° to 60° or 15° to 60°.

[0018] The communication hole of the exhaust passage 122 (exhaust communication hole O2) is disposed at a second azimuth angle θ2 in the counterclockwise direction around the reference axis C when viewed from the central axis of the internal space of the housing 11, and the azimuth angle range is θ2-Δθ2 to θ2+Δθ2. The second azimuth angle θ2 is larger than the first azimuth angle θ1 and is, for example, in the range of 20° to 90°, preferably in the range of 20° to 55°. "Δθ2" is, for example, 1° to 2.5°. The angle φ2 formed by the exhaust direction from the internal space of the housing 11 to the exhaust passage 122 (the extension direction of the exhaust passage 122 near the exhaust communication hole O2) and the tangent direction of the internal space is, for example, in the range of 0° to 60° or 15° to 60°.

[0019] The air intake hole O1 and the exhaust hole O2 are arranged in two directions separated by an azimuth angle deviation θ1+θ2 (e.g., 35° to 120°) when viewed from the central axis of the interior space of the housing 11. Δθ1 (or the area of ​​the air intake hole O1) and Δθ2 (or the area of ​​the exhaust hole O2) may be the same, or one may be larger than the other.

[0020] (Action and effect) In the dental handpiece 1 having this configuration, compressed air is supplied from the compressor to the interior space of the housing 11 through the air supply conduit 101 and the air supply passage 121 by operation by the practitioner. In the air supply circuit communicating with the compressor, the amount of compressed air supplied is adjusted by an air supply volume adjustment mechanism constituted by a pedal or the like of a chair unit. The impeller 2 in the interior space of the housing 11 is driven to rotate by the compressed air, and treatment such as cutting of the patient's teeth is performed by a cutting tool 4 coaxially attached to the shaft 20 of the impeller 2. The compressed air is exhausted from the interior space of the housing 11 to the outside of the dental handpiece 1 through the exhaust passage 122 and the exhaust conduit 102.

[0021] According to the findings of the present inventors, when the intake air passage O1 and the exhaust air passage O2 are respectively arranged in two directions that are separated by an azimuth angle deviation θ1+θ2 of less than 35° when viewed from the central axis of the interior space of housing 11, there is a tendency for the flow resistance of the exhaust from the interior space of housing 11 to the exhaust passage 122 to increase. This is thought to be due to interference between the airflow from the intake air passage 121 toward the interior space of housing 11 and the airflow from the interior space of housing 11 toward the exhaust passage 122, causing a vortex to form near the exhaust air passage O2.

[0022] In light of this finding, in this embodiment, the air supply passage O1 and the exhaust passage O2 are respectively arranged in two directions that are separated by 35° to 120°, where the azimuth angle deviation θ1 + θ2 is 35° or more, when viewed from the central axis of the interior space of the housing 11. This suppresses the above-mentioned airflow interference, thereby improving the efficiency of exhaust from the interior space of the housing 11 to the exhaust passage 122, and thereby improving the rotation efficiency of the impeller 2 and the cutting efficiency of the tip or cutting edge of the cutting tool 4 for cutting an object. Furthermore, the sound volume generated by the high-speed rotation of the impeller 2 by compressed air is also reduced.

[0023] (Second embodiment) 4 shows a first embodiment of the arrangement of the air supply passage 121 and the air exhaust passage 122 relative to the internal space of the housing 11. The second azimuth angle θ2 is larger than the first azimuth angle θ1 and is, for example, in the range of 90° to 125°. Other configurations are substantially similar to those of the dental handpiece 1 of the first embodiment, and therefore the same reference numerals are used to designate the similar configurations and detailed description thereof will be omitted.

[0024] (Action and effect) In light of the above findings, in this embodiment, the air supply passage O1 and the exhaust passage O2 are respectively arranged in two azimuths that are 105° to 155° apart when viewed from the central axis of the interior space of the housing 11, where the azimuth angle deviation θ1 + θ2 is 35° or more. This suppresses the above-mentioned airflow interference, thereby improving the efficiency of exhaust from the interior space of the housing 11 to the exhaust passage 122, and thereby improving the rotation efficiency of the impeller 2 and the cutting efficiency of the tip or cutting edge of the cutting tool 4. Furthermore, the sound volume generated by the high-speed rotation of the impeller 2 by compressed air is also reduced.

[0025] (Third embodiment) 5 shows a third embodiment of the arrangement of the air supply passage 121 and the air exhaust passage 122 relative to the internal space of the housing 11. The impeller 2 is arranged eccentrically in the internal space of the housing 11 so that the distance between the air supply passage O1 and the rotation area of ​​the blade 222 is wider than the distance between the air exhaust passage O2 and the rotation area of ​​the blade 222. Other configurations are substantially similar to those of the dental handpiece 1 of the first embodiment, so the same reference numerals are used to designate the similar configurations and detailed description thereof will be omitted.

[0026] (Action and effect) In light of this finding, in this embodiment, the air intake passage O1 and the exhaust passage O2 are respectively arranged in two directions that are separated by an azimuth angle deviation θ1 + θ2 of 35° or more when viewed from the central axis of the interior space of the housing 11. Furthermore, the distance between the air intake passage O1 and the rotation area of ​​the blades 222 is wider than the distance between the air intake passage O1 and the rotation area of ​​the blades 222. This further reduces the airflow interference described above, thereby improving the efficiency of exhaust from the interior space of the housing 11 to the exhaust passage 122, thereby improving the rotation efficiency of the impeller 2 and the cutting efficiency of the tip or cutting edge of the cutting tool 4 when cutting an object. Furthermore, the sound volume generated by the high-speed rotation of the impeller 2 by compressed air is also reduced.

[0027] (Variation) In the third embodiment, the impeller 2 is disposed eccentrically in the internal space of the housing 11, and therefore the distance between the exhaust manifolds O2 and the rotation area of ​​the blades 222 is designed to be wider than the distance between the air intake manifolds O1 and the rotation area of ​​the blades 222. Alternatively or additionally, the shape or thickness of the housing 11 may be locally adjusted so that the inner surface of the housing 11 is locally recessed radially outward near the exhaust manifolds O2, and therefore the distance between the exhaust manifolds O2 and the rotation area of ​​the blades 222 is wider than the distance between the air intake manifolds O1 and the rotation area of ​​the blades 222.

[0028] (Other embodiments) In the above embodiment, the second azimuth angle θ2 is designed to be larger than the first azimuth angle θ1, but in another embodiment, the second azimuth angle θ2 may be designed to be equal to or smaller than the first azimuth angle θ1. In this case, for example, the first azimuth angle θ1 may be in the range of 30° to 50°, and the second azimuth angle θ2 may be in the range of 0° to 105°.

[0029] In the above embodiment, the first azimuth angle θ1 is in the range of 15° to 30°, but in other embodiments, the first azimuth angle θ1 may be in the range less than 15° (for example, in the range of 5° to 10°). [Industrial Applicability]

[0030] The dental handpiece of the present invention improves the rotational efficiency of the impeller 2 and the cutting efficiency of the tip or cutting edge of the cutting tool 4, thereby contributing to the development of the industry by helping to reduce stress for both dentists and patients. [Explanation of symbols]

[0031] 1. Dental handpiece 101‥Air supply pipe 102...Exhaust duct 104‥Water supply pipe 11. Housing 111. Upper ball bearing 112. Lower ball bearing 114...Through hole 12. Handle side housing 121...Air supply passage 122...Exhaust passage 124‥Water supply passage 2. Impeller 20. Shaft 201...Upper part of shaft 202...Lower shaft 21. First impeller 21-q‥Blade 211...First blade section 212...Second blade section 214. Bridge section 22. Second impeller 22-1~22-12...Blade 4‥Cutting tools 40...File section.

Claims

1. Housing and an impeller disposed in the interior space of the housing so as to be rotatable about an axis for rotating a tooth cutting tool; a handle-side housing attached to the housing and having an air supply passage and an air exhaust passage for the impeller, the deviation in orientation of an air intake communicating hole, which is a communicating hole of the air intake passage to the internal space of the housing, and an exhaust communicating hole, which is a communicating hole of the exhaust passage to the internal space of the housing, relative to a central axis of the housing, is within a range of 35° to 155°; When viewed from a central axis of the internal space of the housing, the air intake communication hole is oriented at a first azimuth angle in a clockwise direction with respect to a reference axis that extends perpendicularly to the central axis along the longitudinal direction of the handle-side housing, and the exhaust communication hole is oriented at a second azimuth angle in a counterclockwise direction that is larger than the first azimuth angle, The distance between the exhaust communication hole and the rotation area of ​​the impeller is configured to be greater than the distance between the air supply communication hole and the rotation area of ​​the impeller. Dental handpiece.

2. 2. The dental handpiece according to claim 1, The first azimuth angle is in the range of 15° to 30°, and the second azimuth angle is in the range of 20° to 125°. Dental handpiece.

3. 3. The dental handpiece according to claim 2, The first azimuth angle is in the range of 15° to 30°, and the second azimuth angle is in the range of 20° to 55°. Dental handpiece.

4. 2. The dental handpiece according to claim 1, In a plan view perpendicular to the central axis of the interior space of the housing, the angle formed by the extending direction of each of the air intake manifold and the exhaust manifold and the tangent direction of the interior space or the inner surface of the housing is within a range of 0° to 60°. Dental handpiece.

5. 2. The dental handpiece according to claim 1, The impeller is eccentrically disposed in the internal space of the housing, so that the distance between the exhaust communication hole and the rotation area of ​​the impeller is greater than the distance between the air supply communication hole and the rotation area of ​​the impeller. Dental handpiece.

6. The dental handpiece according to claim 1 or 5, The inner surface of the housing is locally recessed at the exhaust manifold, so that the distance of the exhaust manifold from the rotation area of ​​the impeller is greater than the distance of the air intake manifold from the rotation area of ​​the impeller. Dental handpiece.

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