JP3377144B2 - Handpiece rotating body and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small fluid-driven turbine type handpiece (hereinafter referred to as a small-fluid-driven turbine handpiece) which is useful for machining work, medical treatment and the like, and a manufacturing method thereof. More specifically, the present invention relates to a small fluid-driven turbine handpiece which is particularly excellent in durability and sterilization (sterilization) processability, and an economical manufacturing method thereof.

[0002]

2. Description of the Related Art Conventionally, small fluid-driven turbine handpieces have been used, for example, for cutting materials, or for medical purposes, orthopedics in surgery (eg, brain surgery, orthopedics, oral surgery, otolaryngology, etc.). In surgery or plastic surgery, ・ In dental treatment of teeth, excavation of bones and teeth,
It is widely used for opening, cutting, cutting and polishing. Among the small fluid-driven turbine handpieces described above, a small-sized dental fluid-driven turbine handpiece that uses pressurized air as a pressurized fluid that is a drive medium of a turbine is called a dental air turbine handpiece. For the sake of convenience of explanation, the prior art and the present invention will be described below using the dental air turbine handpiece as an example. The external shape of the dental air turbine handpiece is as shown in FIG. That is,
As shown in FIG. 1, the dental air turbine handpiece (A) has a head portion (H) and a grip portion (G).
It consists of The neck portion (N) of the grip portion (G) is connected to the head portion (H) and supplies / exhausts pressurized air to / from an air turbine arranged in the head portion (H). Has inside. In the figure, T indicates a tool such as a cutting tool.

The above-mentioned air turbine is composed of a rotary shaft which is rotationally driven by pressurized air and an impeller arranged on the outer peripheral surface of the rotary shaft, and is hereinafter referred to as a handpiece rotary body. . The structure of a conventional handpiece rotating body is shown in FIGS. That is, FIG.
FIG. 3 shows the structure of this type of dental air turbine handpiece (A), particularly the internal structure of the head portion (H) and the neck portion (N) connected to the head portion (H). . 2 to 3, the structure of a conventional handpiece rotating body (B ') applied to this type of dental air turbine handpiece (A) is also shown. 2 is a sectional view taken along the axis of the rotary shaft (2 ') of the handpiece rotary body (B'), and FIG. 3 is I of FIG.
It is a -I line sectional view.

As shown in FIG. 2, the handpiece rotating body (B ') has a head (1) of the head portion (H).
It is arranged in the chamber (11). Then, the handpiece rotating body (B ′) has a rotating shaft (2
′) Having an impeller (3 ′) on the outer peripheral portion thereof, and the rotating shaft (2 ′) is rotatably supported inside the head (1) via a bearing portion (4). As shown in the figure, the head (1) is composed of a head body (12) and a cap portion (13), and the head body (12).
Impeller (3 ') of handpiece rotating body (B') inside
A chamber (11) for arranging is formed.

As shown in the figure, a tool shaft (5 ') such as a dental cutting tool is fixedly held at the shaft center of the rotary shaft (2') of the handpiece rotary body (B '), and various types of tools are held. Dental treatment is performed. In addition, in the illustrated one, the rotary shaft (2
′) Has a chuck (51 ′) of a friction type chuck mechanism for holding the tool shaft (5 ′) therein. Needless to say, a one-touch chuck mechanism known as a chuck mechanism may be used.

Another configuration of this type of dental air turbine handpiece (A) will be described with reference to FIG. As shown in FIG. 2, the bearing portion (4) includes an inner ring (inner race) (41), an outer ring (outer race) (42),
The ball bearing is composed of a ball (43) and a retainer (44). It should be noted that an O-ring for the centripetal center and a known mechanism for increasing the shaft rigidity may be arranged on the outer circumference and the side part of the bearing portion (4). Although the one shown in the drawing is a ball bearing using a ball (43), it may be one of a known air bearing mechanism called an air bearing. Further, in the conventional dental air turbine handpiece (A), the treatment site is irradiated to the head body (12) of the head portion (H) or the body (6) of the neck portion (N), which is not shown. A lighting system for doing so, a water supply channel for sprinkling water or physiological saline on a treatment site to remove cutting heat of bones and teeth, and for cleaning may be provided.

FIG. 3 illustrates a manner of supplying / exhausting pressurized air of a conventional dental air turbine handpiece (A). That is, in the conventional dental air turbine handpiece (A), pressurized air is supplied to the air supply passage (7) arranged in the main body (6) of the neck portion (N), and the pressurized air is supplied. After introducing into the chamber (11) through the air supply port (71) and injecting it into the impeller (3 ') to generate a rotational driving force on the rotating shaft (2'), the main body (6) of the neck portion (N).
It is carried out by guiding the gas from the exhaust port (81) provided therein to the exhaust passage (8) and discharging it. In the figure, in the arrows showing the pressurized air flow in the chamber (11) of the head portion (H), the solid arrows show the chamber (1).
The component circulating between the inner wall surface of 1) and the impeller (3 ') is
Further, the dotted arrows indicate the components circulating in the space formed between the upper and lower inner wall surfaces of the chamber (11) and the upper and lower portions of the impeller (3 '). As an exhaust mode, there is a method of reducing these circulation components as much as possible, and in this case, the handpiece has an extremely high performance, and this point has been previously proposed by the present inventors (for example, Japanese Patent Application No. 6-58242). −
36404).

In the dental air turbine handpiece (A) having the above structure, the structure of the handpiece rotating body (B ') applied to the handpiece (A) has recently been
It has been particularly problematic. This is because the high performance of this kind of handpiece is progressing for the purpose of speeding up treatment and reducing patient's pain. Specifically, high speed rotation (conventional 20 to 350,000 rpm) is performed. From 35 to 50
(Development to 10,000 rpm) is in progress, and high durability and vibration resistance of the handpiece rotating body under high speed rotation are required. In addition, since it is an intraoral treatment device, strict sterilization (sterilization) treatment has been required in consideration of infections such as AIDS and hepatitis, and the structure has been reviewed in order to reduce the manufacturing cost. Is required.

In this regard, in the conventional dental air turbine handpiece (A), the rotary shaft (2 ') and the impeller (3)
Various structures are provided as the structure of the handpiece rotating body (B ′) made of ′). For example, Jikkou 54-3
Japanese Patent No. 5999 discloses a structure in which a plurality of blades that project outward from the outer peripheral surface of a cylindrical base are integrally formed using a homogeneous resin material to form an impeller, and the impeller is fitted to a main shaft. Are shown. According to the above proposal, since the impeller is molded with a homogeneous resin material, the weight is lighter than that of metal, the inertial mass of the handpiece rotating body is reduced, and the damage of the handpiece head due to the damage of the impeller is reduced. It is said that reduction in manufacturing cost will be achieved because plating for rust prevention is unnecessary. However, although the structure described above ensures the manufacturing efficiency because the impeller integrally molded using a resin material is mechanically fitted to the main shaft, it does not satisfy the high-level required characteristics. Absent. More specifically, since the impeller is fitted to the main shaft, separation of both members under ultra-high speed rotation, slippage of the impeller and main shaft induced by the separation and destruction of members,
There are drawbacks such as breakage, further, invasion of bacteria to the mating contact surface based on simple mechanical fitting, and difficulty in complete sterilization.

Further, Japanese Patent Laid-Open No. 4-197254 discloses a chuck in which a hollow rotary shaft and an impeller are integrally formed of plastic (or ceramic) and a tool is detachably mounted in the hollow rotary shaft. The handpiece rotating body of the arranged structure is shown. That is, in the above-mentioned one, the rotary shaft of the handpiece and the impeller are integrally molded with plastic to reduce the manufacturing cost.
However, even in this type of lightweight structure,
Like the above Japanese Utility Model Publication No. 54-35999, the demand for higher performance cannot be realized. Especially, under high speed rotation (high speed rotation of the conventional 20 to 35 rpm to 35 to 50 rpm or higher), the handpiece rotating body in which the hollow rotating shaft and the impeller are integrated with each other is manufactured at a low manufacturing cost. Although the number can be reduced, the rotating shaft is also made of plastic, so there is a great difficulty in durability such as damage or destruction of the bearing part.

Therefore, the one disclosed in the above publication can be used in a low speed range, and the durability cannot be obtained because the rotary shaft is made of plastic. Further, since it is a plastic molding, it is difficult to maintain the center of rotation (rotational balance), especially under high-speed rotation, due to fluctuations in processing conditions, which leads to deterioration of durability of the handpiece rotating body.

[0012]

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned drawbacks of the prior art. In particular, the present invention is a dental handpiece that is required to have higher performance and higher rotation speed (such as securing a large torque while saving energy) aiming at improving treatment speed and reducing patient pain. In the above, the handpiece rotating body, which is the main component of the above, has a new structure. INDUSTRIAL APPLICABILITY The present invention requires that the metal rotary shaft and the impeller made of plastic be connected to each other, and that the durability and heat resistance for sterilization under severe use conditions of high-speed rotation and resistance to sterilization are high. This was completed based on the finding that it is essential to integrate both members by integral molding (insert molding) in consideration of sterilization treatment including chemical properties.

The inventors of the present invention have previously proposed a small fluid-driven turbine handpiece that rotates at a much higher speed than before (Japanese Patent Application Nos. 6-35404 and 6-15436).
6), 6-154367, and 6-154368). The direct motivation for the present invention lies in the need to develop a handpiece rotating body that is applicable to the above-described handpiece of high-speed rotation and large torque generation system and is excellent in durability and economy. INDUSTRIAL APPLICABILITY According to the present invention, a rotating body of a handpiece excellent in durability, sterilization (sterilization) processability and the like applied to a small-sized fluid-driven turbine handpiece of high-speed rotation and large torque generation system is economically provided.

[0014]

If it outlined present invention According to an aspect of the present invention, a dental ha consisting of an impeller provided in the rotary shaft and the outer peripheral portion of the metal to be rotationally driven by pressurized fluid
The present invention relates to a handpiece rotary body used for a handpiece and a manufacturing method thereof, and in particular, the handpiece rotary body has a concavo-convex portion on an outer peripheral portion of a metal rotary shaft and a synthetic resin on an outer peripheral portion of the metal rotary shaft. It is characterized in that an impeller is integrated with the outer peripheral portion of the metal rotary shaft by injection molding. In addition, the handpiece rotating body has a metal rotating shaft having an uneven portion formed on the outer peripheral portion disposed in an injection molding die, and a synthetic resin material is injection molded on the outer peripheral portion of the rotating shaft. The impeller is integrally formed on the outer peripheral portion of the metal rotary shaft.

Furthermore, the present invention is the addition to replacing the metal cutting tool shaft for rotating the metallic rotary shaft pressurized fluid for rotating the pressurized fluid, combining an outer peripheral portion of the cutting tool axis The present invention also relates to a handpiece rotating body used for a dental handpiece having a structure in which a resin rotary shaft and an impeller are integrated, and a manufacturing method thereof. In addition,
In the present invention, the metal cutting tool shaft is understood to mean that not only the cutting tool but also various tools applied to this type of handpiece can be arranged at the shaft end. Should be.

Hereinafter, the technical constitution and embodiments of the present invention will be described in detail with reference to the drawings. Needless to say, the present invention is not limited to the illustrated one.

FIG. 4 is a diagram for explaining the first embodiment of the handpiece rotating body (B) of the present invention. FIG. 4 corresponds to the handpiece rotating body (B ′) arranged in the chamber (11) of the head (1) of the head portion (H) of the dental air turbine handpiece (A) of FIG. 2. It is a thing. The symbols (alphabetic characters and numbers) indicating the element members in the drawings are shown with a (') dash in the conventional one, and with the symbol without a (') dash in the present invention. . Therefore, the same symbols in both have the same meaning, and the description thereof will be omitted. Further, the handpiece rotating body (B) of the present invention is not only applied to the dental air turbine handpiece (A) described above, but is widely applied to small fluid-driven turbine handpieces. Further, it is not limited to the term handpiece and is used not only in the form of being gripped and used in the hand, but also as the rotating body of a small fluid drive turbine handpiece used as a component of equipment. Is.

As shown in FIG. 4, the handpiece rotating body (B) of the first embodiment of the present invention comprises a metallic rotating shaft (2).
The impeller (3) made of synthetic resin is integrally formed on the outer peripheral surface of the. In the present invention, the metal rotary shaft (2) may be made of metal, for example, SUS 420 J2 made of stainless steel. In the present invention, the metal rotary shaft (2), which is arranged in advance in an injection molding die (not shown), has an outer peripheral surface (21), particularly an outer periphery on which the impeller (3) is integrally molded. It is preferable that the surface (22) has a concavo-convex portion (23). The concavo-convex portion (23) may be fine concavo-convex or a spiral groove, and its processing method is not particularly limited. For example, any method such as mechanical working such as knurling or plastic working may be used. In short, the concavo-convex portion (23) includes a structure in which only the groove and the concave portion are provided on the cylindrical side surface of the metallic rotating body (2), or one in which only the convex portion opposite to the above-described aspect is formed. Is something
It is sufficient that the side surface of the rotating body (2) is relatively concave and convex. Furthermore, the outer peripheral surface (21) of the rotating shaft (2) is
As shown in the figure, the part (2
It is preferable to have 4).

In the present invention, the impeller (3) integrally formed on the outer peripheral portion of the rotary shaft (2) is made of injection-moldable synthetic resin. The injection-moldable synthetic resin material includes high-speed rotation of the handpiece rotating body (B),
Considering the heat distortion resistance in an autoclave for sterilization, it is preferable that the tensile strength is 1000 kgf / cm ² or more and the heat distortion temperature is 150 ° C. or more. As for the latter heat distortion temperature characteristic, AST is defined by the characteristic under load.
Those having a MD-648 (load of 6.4 kg / cm ² ) of 135 ° C. or higher are preferable.

The synthetic resin satisfying the above conditions may be either thermoplastic or thermosetting as long as injection molding is possible. Examples of the injection-moldable synthetic resin include polyamide-imide resin, polyether nitrile resin, polyether imide resin, polyether ether ketone resin, polyimide resin, polyether sulfone resin, polyphenylene sulfide resin material and reinforced materials thereof. And so on. In particular, as described above, the dimensions and shape accuracy of the injection molded product are required to be high in order to correspond to the high performance of the rotating body of the handpiece, and as such a synthetic resin material to be used, polyether nitrile resin is used. The non-reinforcing materials of are preferred. As the reinforcing material, a desired fiber reinforcing material such as carbon fiber or glass fiber, or Zn having an antibacterial property and having a higher density than the resin material is used.
A reinforcing material containing O, Ag, TiO ₂ , hydroxyapatite or the like as a filler can be used.
With the above-mentioned materials, it is possible to prevent the growth of bacteria in the chamber, adjust the density of the rotating body, and facilitate more precise balance correction.

FIG. 5 is a view for explaining the second embodiment of the handpiece rotating body (B) of the present invention. The major difference between the second embodiment and the first embodiment is that the rotary shaft (2) is composed of the tool shaft itself, and the rest of the structure is substantially the same.

FIG. 6 is a view for explaining a third embodiment of the handpiece rotating body (B) of the present invention. In the third embodiment, the metal tool shaft (5) is arranged in advance in the injection molding die, and the rotary shaft (2) is provided in the region including the unevenness forming portion (53) on the outer peripheral surface (52) of the metal. The impeller (3) is integrally molded at the same time. As a result, the tool shaft (5), the rotary shaft (2) and the impeller (3) are firmly integrated.

[0023]

EXAMPLE A dental hand pee according to the embodiment shown in FIG.
The handpiece rotating body (B) used for the table was manufactured.
That is, an impeller (3) was attached to a portion of the outer peripheral surface (22) of the stainless steel (SUS 420J2) rotating shaft (2) that was previously placed in the injection mold (polyether nitrile resin, ID300 manufactured by Idemitsu Kosan Co., Ltd.). ) Non-reinforced material was injection-molded and both elements were integrally molded to produce a handpiece rotating body (B). In the outer peripheral surface (22) of the rotary shaft (2), a portion (23) where the impeller (3) is integrally molded is made knurled to make it uneven so that both elements can be securely fixed. Further, a portion (24) of the outer peripheral surface (22) of the rotary shaft (2) where the bearing mechanism (4) is arranged is finished by centerless grinding. The handpiece rotating body (B) manufactured as described above is supported by ball bearings without any balance correction, and the pressure is 500,000 rpm using pressurized air.
It was rotated continuously with. After one hour, no abnormality was found in the rotating body (B) of the handpiece. On the other hand, the conventional handpiece rotating body (B ') manufactured by fitting the impeller (2') and the rotating shaft (2 '), which are separately prepared by injection molding, and adjusting the balance is rotating. About 30
Detachment was seen in both elements at 10,000 rpm, impeller (2 ') and
Chamber (11 ') of head (1') of handpiece
Damage to the wall was observed.

[0024]

The rotating body of the handpiece, which is the main component of the dental handpiece of the present invention, has recently been improved in performance and
In order to cope with high-speed rotation and stricter sterilization (sterilization) processing, a synthetic resin impeller is integrated with the metal rotary shaft by injection molding, or a synthetic resin is used on the metal tool shaft. It is manufactured by integrating a rotary shaft and an impeller manufactured by injection molding.

In order to meet the above-mentioned requirements (needs) for the dental handpiece, that is, high performance, high speed rotation (securing a large torque force under energy saving), and stricter sterilization (sterilization) treatment. Therefore, it is essential to integrate the respective constituent members of the handpiece rotating body, which is the main constituent element, by the injection molding.

The rotating body is processed by the method for manufacturing the rotating body of the handpiece used in the dental handpiece of the present invention.
Not only is the assembly cost reduced, but separation between the rotating body members (parts) in the rotational and axial directions and slippage are completely prevented. That is, according to the present invention, a handpiece rotating body having sufficient bonding strength, good rotational balance, and sufficient durability can be economically manufactured. In addition, a handpiece rotating body manufactured using a material that has a tensile strength of 1000 kgf / cm ² or more as an injection-moldable synthetic resin material can rotate at a high speed of 350,000 rpm or more. It can be applied to high-performance handpieces. Further, the handpiece rotating body manufactured using a material having a heat distortion temperature of 150 ° C. or higher can be sterilized and disinfected at a high temperature. In addition,
In the sterilization process, the contact surfaces of the members of the handpiece rotating body (rotary shaft and impeller, etc.) are in close contact with and integrated with each other, so that bacteria etc. are prevented from entering the contact surfaces and complete sterilization (sterilization) It goes without saying that you can do Further, by using a material that can obtain high dimensions and shape accuracy of the injection molded product, the density of the synthetic resin material is also helped, and the advantage that the balance correction process of the rotating body can be omitted can be enjoyed. You can

[Brief description of drawings]

FIG. 1 is a perspective view of a small (dental) air turbine handpiece to which a handpiece rotating body of the present invention is applied.

FIG. 2 is a longitudinal sectional view of a main part of the small (dental) air turbine handpiece of FIG.

3 is a cross-sectional view taken along line I-I of FIG.

FIG. 4 is a diagram illustrating a handpiece rotating body according to the first embodiment of the present invention.

FIG. 5 is a diagram illustrating a handpiece rotating body according to a second embodiment of the present invention.

FIG. 6 is a diagram illustrating a handpiece rotating body according to a third embodiment of the present invention.

[Explanation of symbols]

A: Small (dental) air turbine handpiece B to which the handpiece rotor of the present invention is applied B: Handpiece rotor G: Grip part H: Head part 1 ... ………… Head 11 ………… Chamber 12 ………… Head body 13 ………… Cap section 2, 2 '………… Rotation shaft 21 ………… Outer circumferential surface 22 of rotation shaft ………… Blades Rotating shaft outer peripheral surface 23 at the position where the vehicle is arranged ............ Concavo-convex portion 24 on the rotating shaft outer peripheral surface ............ Rotating shaft outer peripheral surface 3 and 3'at the position where the bearing is disposed Impeller 4 Bearing section 41 Inner ring 42 Outer ring 43 Ball 44 Retainer 5, 5 '... Tool shaft 51, 51' ... Chuck 52 ............ Tool shaft outer peripheral surface 53 at a position where an impeller or a rotary shaft is arranged. ... Tool shaft outer peripheral surface irregularity 54 .... Tool shaft outer peripheral surface 6 at the position where the bearing is arranged ... Neck body 7 ... Air supply passage 71 ... Air supply port 8 ... ………… Exhaust path 81 ………… Exhaust port

─────────────────────────────────────────────────── ─── Continuation of front page (72) Takashi Minami, 6, 206 Fujigaoka, Kuwana City, Mie Prefecture (72) Inventor, Politics, 5233, 2233, Touhou, Kuwana City, Mie Prefecture (Japanese Patent Laid-Open No. 7- 222755 (JP, A) JP-A-5-176944 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) A61C 1/05 A61C 1/08

Claims (6)

(57) [Claims] 1. A <br/> hand by pressurized fluid used in the dental handpiece of the high speed rotation comprising a synthetic resin impeller provided in the rotary shaft and the outer peripheral portion of the metal for rotating In the piece rotating body, the handpiece rotating body is provided with an impeller made of synthetic resin as a rotating shaft made of metal.
Use the one that has irregularities on the outer peripheral part of the
Tensile strength of 1000kgf / c on the outer circumference of the metal rotating shaft
Injection molding of synthetic resin with m ² or more and heat distortion temperature of 150 ° C or more
Shape to form an impeller, and
A handpiece rotating body for use in a dental handpiece, which is composed of an integrated synthetic resin impeller. 2. A <br/> hand by pressurized fluid used in the dental handpiece of the high speed rotation comprising a synthetic resin impeller provided in the rotary shaft and the outer peripheral portion of the metal for rotating In the method of manufacturing a piece rotating body ,
Outside the area where the impeller made of synthetic resin is placed as the rotating shaft
The one with irregularities on the circumference is placed in the injection mold.
The tensile strength is 1000k on the outer circumference of the metal rotary shaft.
Synthetic resin with gf / cm ² or more and heat distortion temperature of 150 ° C or more
Is formed into an impeller by injection molding, and a synthetic resin impeller is integrated with an outer peripheral portion of the metal rotating shaft to be used as a dental handpiece rotating body. Production method. 3. The dentistry according to claim 2, wherein the rotating shaft made of metal has a hollow portion and holds the rotating tool shaft.
For manufacturing a rotating body of a handpiece used for a handpiece for a car. 4. The dental handpiece according to claim 2, wherein the rotating shaft made of metal constitutes a rotating tool shaft.
A method of manufacturing a handpiece rotating body used. 5. The metal cutting tool shaft for rotating the pressurized fluid, the high speed dental comprising a synthetic resin rotating shaft and an impeller provided on an outer peripheral portion of the cutting tool axis
In a handpiece rotary body used for a handpiece, the handpiece rotary body is a metal cutting tool shaft and
The concave part on the outer periphery of the part where the synthetic resin rotary shaft is installed.
Use the one with a convex part,
Tensile strength of 1000 kgf / cm ₂ or more on the outer periphery , thermal deformation
Injection molding synthetic resin with a temperature of 150 ℃ or higher
Form an impeller and fit the outer circumference of the metal cutting tool shaft.
A rotating body of a handpiece used in a dental handpiece , characterized in that a rotary shaft made of synthetic resin and an impeller are integrated. 6. The metal cutting tool shaft for rotating the pressurized fluid, the high speed dental comprising a synthetic resin rotating shaft and an impeller provided on an outer peripheral portion of the cutting tool axis
In a method for manufacturing a handpiece rotary body used for a handpiece, the handpiece rotary body is made of metal.
The part where a synthetic resin rotary shaft is installed as the cutting tool shaft
If there is unevenness on the outer periphery of the
Installed, and the tensile strength is 10 at the outer periphery of the metal cutting tool shaft.
00kgf / cm ² or more, heat distortion temperature 150 ° C or more
A dental handpiece characterized in that a synthetic resin is injection-molded to form a rotary shaft and an impeller, and a synthetic resin rotary shaft and an impeller are integrated on an outer peripheral portion of the metal cutting tool shaft.
A manufacturing method of a handpiece rotating body used for a cloth.