JP3122310B2 - Small fluid driven turbine handpiece - 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-sized fluid-driven turbine type handpiece useful for machining and medical use. More specifically, the present invention relates to a method for removing contaminants such as cutting chips near a tool shaft such as a cutting tool fixed to a head portion of a handpiece during operation or stop of the handpiece. The present invention relates to a small-sized fluid-driven turbine handpiece that prevents the suction of air into the head.

[0002]

2. Description of the Related Art Conventionally, small fluid-driven turbine handpieces have been used, for example, for cutting materials or for medical use. In orthopedic surgery in surgery (brain surgery, plastic surgery, oral surgery, otolaryngology), It is widely used for cutting, cutting and cutting bones and teeth in oral treatment in dentistry.

[0003] In the above-mentioned small fluid-driven turbine handpiece, for example, a small-sized fluid-driven turbine handpiece for dental use of pressurized air as a pressurized fluid as a driving medium of a turbine is called a dental air turbine handpiece. The external shape is as shown in FIG. 1 which will be referred to in the description of the technical configuration of the present invention described later.
That is, as shown in FIG. 1, the dental air turbine handpiece (A) includes a head (H) and a neck (N) connected to the head (H). The neck portion (N) has a mechanism for supplying and exhausting pressurized air to and from the air turbine disposed in the head portion (H). In FIG. 1, (G) shows a grip portion (grip portion), and (B) shows a tool fixed and held on a rotor shaft of an air turbine. Hereinafter, for the sake of convenience of explanation, the prior art and the present invention will be described by taking the dental air turbine handpiece using pressurized air as a drive medium of the turbine as a typical example of a small fluid-driven turbine handpiece.

Needless to say, in the present invention, the drive medium of the turbine is not limited to the pressurized air. For example, the pressurized fluid as the drive medium of the turbine is not limited to pressurized air, and various types of pressurized liquid such as pressurized liquid and pressurized gas including pressurized steam are used. Therefore, in the following description, the terms air supply / air supply port and exhaust / exhaust port used in connection with pressurized air refer to supply / supply port or discharge / exhaust port when other pressurized fluid is applied. Needless to say, it has to be read. Further, the application field of the small fluid-driven turbine handpiece of the present invention is not limited to the above-mentioned dental use, but is widely applied to fields such as material cutting and medical use. Furthermore, it goes without saying that in these application fields, not only a handpiece that is used by being held by a hand as a handpiece, but also a component (member, part) of a device may be used. It is.

[0005] The structure of a conventional dental air turbine handpiece, particularly the internal structure of a head portion and a neck portion (N) connected to the head portion, will be described later. The first embodiment of the present invention will be described with reference to FIG. In addition,
The structure of the prior art dental air turbine handpiece will be described with reference to FIG. 2 according to the first embodiment of the present invention. FIG. 2 clarifies the problems of the prior art and the means for solving the problems. Because there is. Specifically, in FIG.
Those excluding the communication passages (reference numbers: 4, 41, 42...) Belong to the related art.

As shown in FIG. 2, a head portion (H) of this type of air turbine handpiece has a turbine blade (31) at a peripheral portion in a chamber (12) inside a head body (1). A turbine rotor shaft (3) is arranged, and the turbine rotor shaft (3) is rotatably supported inside a head body (1) via a bearing (2).

As shown in FIG. 2, the head main body (1) has a head cap (13) at an upper part, a lower part (14) at a lower part, and a lower part (14). The turbine rotor shaft (3) has an opening (141) for projecting a lower portion thereof. As shown in FIG. 2, the head cap (13) is used to fix the head cap (13) to the head body (1) or to remove the tool shaft (5) from the turbine rotor shaft (3). Hole (13
1).

As shown in FIG. 2, a tool shaft (5) such as a dental cutting tool is fixedly held at an axis of the turbine rotor shaft (3), and various treatments are performed. A chuck (51) for gripping the tool shaft (5) is provided on the peripheral side of the tool shaft (5) as shown in the figure. Although the illustrated chuck (51) is of a friction type chuck mechanism, it goes without saying that it may be of a known one-touch chuck mechanism. When the chuck mechanism is a one-touch type, a head cap (13) having no hole (131) is used. However, a slight gap (machine) is provided between the head body (1) and the one-touch chuck mechanism. (Including component tolerances).

As shown in FIG. 2, the bearing (2)
Are inner race (inner race) (21), outer race (outer race) (2)
2) A ball bearing mechanism comprising a ball bearing composed of a ball (23) and a retainer (24). It should be noted that a known mechanism such as a wave washer for increasing the shaft rigidity or an O-ring for centering the shaft may be provided at the end or the side of the bearing portion (2). Needless to say.

As shown in FIG. 2, a neck portion (N) connected to the head portion (H) has a main body (6).
An air supply / exhaust system to the chamber (12) is provided inside the chamber. Specifically, in the air supply / exhaust system, pressurized air is injected into the chamber (12) from the air supply port (7a) of the air supply path (7), and the pressurized air in the chamber (12) is It is led to the exhaust path (8) from the exhaust port (8a),
It is configured to be exhausted out of the system. Although not shown, it goes without saying that a water supply channel, a lighting pipe, and the like may be provided in the main body (6) of the neck portion (N).

In FIG. 2, which shows the structure of a conventional dental air turbine handpiece, it should be particularly noted that, due to the structure, contaminants such as cutting chips are supplied from inside and outside of the head body to the inside of the head when the operation of the handpiece is stopped. The point is that it has a structure that allows easy suction. As described above, the route of the contaminants entering the inside of the head main body is such that the turbine rotor shaft (3) is disposed at the opening (141) of the lower surface (14) of the head main body (1). (141a), the gap (2a, 2b) formed between the bearing (2) and the head cap (13) and the head body (1) member, and the head cap (13).
Opening (131).

The suction of the contaminants into the head body has been regarded as a problem in this type of dental air turbine handpiece. Suction of the contaminant into the chamber inside the head body (1) is due to the following reasons. That is, when the handpiece is stopped, even if the air supply system is shut off, the turbine rotor continues to rotate for a short time, so that the inside of the chamber becomes negative pressure, and contaminants such as cutting chips near the tool shaft are removed. It will be sucked into the head body (1).

One method for preventing the aforementioned contaminants from being sucked into the handpiece is disclosed in Japanese Patent Application Laid-Open No. 5-42169. This relates particularly to the prevention of foreign matter such as cutting chips from entering the inside of the head body during the operation of operating the dental handpiece. Specific measures to prevent the intrusion of contaminants by the above proposal are as follows. (i) An opening for projecting one end of a bar sleeve (corresponding to the above-described turbine rotor shaft) is provided at a lower end surface of a cartridge case (corresponding to the above-described head body), and an outer peripheral surface of the bar sleeve. And the inner peripheral surface of the opening is concentrically separated. (ii) In the concentric separating portion, predetermined members, that is, a fixed partition member, a rotary partition member (dustproof disk), and a disk cover are used, and the first member is connected to each other and in a ring shape. The gap, the second gap, and the third gap are arranged so as to be formed. According to the above configurations (i) and (ii), the rotation radius of the member varies with the rotation of the bar sleeve, so that the airflow located at the first to third gaps becomes faster in this order. In other words, the pressure in the third gap can be minimized. Therefore, contaminants such as cutting chips are sucked into the third gap, but are prevented from entering the first and second gaps. The sucked contaminants are discharged to the outside through an opening provided in the disk cover.

The measures proposed to prevent contaminants from entering the inside of the head body according to the above proposal are complicated in structure and insufficient in operation and effect. For example, it is not effective for the problem of intrusion from the head cap portion at the upper part of the head main body, and particularly for the problem of intrusion of contaminants in a negative pressure state in the chamber when the operation is stopped.

[0015]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems of the prior art. The present inventors diligently studied prevention of contaminants such as cutting chips from entering the inside of the head main body at the time of operation stoppage as well as at the time of operation operation in a small fluid drive turbine handpiece for medical use such as dentistry.

As a result, when the operation of the handpiece is stopped, there is a difference in the pressure distribution in the chamber inside the head main body. More specifically, a negative pressure is applied to the center of the chamber.
When the chamber peripheral side has a slight positive pressure, and when a bypass is provided from the chamber peripheral side to the bearings disposed above and below the chamber, the difference in the pressure distribution inside the head main body is canceled. It has been found that since airflow is generated in the head, contaminants can be effectively prevented from entering the inside of the head body. The present invention has been completed on the basis of the above findings, and prevents dental substances such as cutting chips from entering the inside of the head main body, and in particular, prevents dental substances from entering the bearing portion and the chamber. And other medical fluid-driven turbine handpieces.

[0017]

SUMMARY OF THE INVENTION In summary, the present invention is directed to a chamber (1) of a head body (1) of a head section.
2) a head portion (H) having a turbine blade (31) of a turbine rotor shaft (3) rotatably supported by a bearing portion (2) disposed in the head portion; H) and a supply path for supplying a pressurized fluid to a turbine blade (31) disposed in the chamber (12) and a discharge path for discharging the pressurized fluid in the chamber (12). A handpiece body (B) having therein a handpiece body (B), wherein (i) the head portion (H) is arranged from the circumferential side of the chamber (12) of the head body (1). Above and below the chamber (12)
A small fluid-driven turbine handpiece having a communication passage (4) that communicates with an end face portion of the bearing portion (2) through the outside thereof. Things.

Hereinafter, the technical configuration and embodiment of the present invention will be described in detail with reference to the drawings, taking the dental air turbine handpiece described above as an example. It is needless to say that the present invention is not limited to the illustrated one.

FIGS. 1 to 3 are views for explaining a dental air turbine handpiece (A) according to a first embodiment of the present invention. As described above, FIG. 1 is a perspective view, FIG. 2 is a longitudinal sectional view of the tool shaft (C) in FIG. 1 in the axial direction, and FIG.
FIG. 2 is a sectional view taken along line II of FIG. Here, the cause of the inside of the head body of the dental air turbine handpiece being contaminated by contaminants such as tooth chips and the like will be described. During the operation of the handpiece (A), the inside of the chamber (12) formed inside the head body (1) of the head portion (H) flows from the air supply port (7a) of the air supply passage (7). Due to the injection of the pressurized air and the rotation of the turbine rotor shaft (3), a slight positive pressure (+) is obtained. Therefore, the chamber (12), two sets of bearings (2) disposed above and below the chamber (12), and the bearing (2) and the head cap (13) or the lower surface (14) of the head body. ), The inside of the head main body (1) is not contaminated by the contamination path including the opening (141). This is because the positive pressure (+) is applied to the contamination path. However, as described below,
If the positive pressure (+) is positively applied to the contamination path during operation of the handpiece, it goes without saying that contamination by contaminants is reliably prevented.

On the other hand, when the operation of the handpiece (A) is stopped, the turbine rotor shaft (3) keeps inertial rotation even after the air supply from the air supply passage (7) is cut off. Is pressed against the inner peripheral wall (123) of the chamber by centrifugal force, and the air supply path (7) and the exhaust path (8)
Both have a slight positive pressure (+) and the chamber (1
The center part of 2) becomes a negative pressure (-). As described above, since the central portion of the chamber (12) is at a negative pressure (-), contaminants such as cutting chips are sucked into the head body (1) through the above-described contaminant path. Contaminants are sucked into the center of the chamber (12) through the inner ring (21) and the outer ring (22) of the bearing (23), thereby contaminating the inside of the chamber (12). It goes without saying that the contamination and damage of the bearing portion (2) also increase in the contamination process.

The present invention was conceived by elucidating the cause of the contaminants being sucked into the head body (1), and the main point is that the contaminants are located on the peripheral side of the chamber (12) and the bearing (2). Bypass is installed, positive pressure (+) and negative pressure (-)
Is to prevent suction of the contaminants so that In the present invention, the above-mentioned bypass is provided in the chamber (12) of the head body (1) as shown in FIG.
And a communication path (4) that communicates from the inner wall surface to the bearing part (2).

More specifically, as shown in FIG. 2, the communication path (4) is formed in the chamber (1) of the head body (1).
The inner wall portion of (2), particularly the upper and lower inner wall portions (121, 122) near the chamber peripheral side inner wall portion (123), which is a positive pressure (+), is disposed above and below the chamber (12). Two sets of communication paths (41) are connected to the end face of the bearing (2).
, 42 and 43 and 44) are provided. In addition,
In the present invention, the communication path (4) is configured such that a pair of communication paths is disposed from the chamber (12) to the end faces of the upper and lower bearings (2) as in a second embodiment described later. Needless to say, it is good. FIG. 3 shows FIG.
FIG. 2 is a sectional view taken along line II of FIG. FIG. 3 particularly illustrates the air supply / exhaust system in the dental handpiece (A) of the first embodiment. The features of the air supply / exhaust system of the first embodiment will be described later in relation to the handpiece of the second embodiment.

FIGS. 4 and 5 illustrate a dental air turbine handpiece (A) according to a second embodiment of the present invention. FIG. 4 is a view corresponding to FIG. 2, and FIG. 5 is a sectional view taken along line II-II of FIG. The major differences between the air turbine handpiece (A) of the second embodiment shown in FIGS. 4 and 5 and that of the first embodiment shown in FIGS. 2 and 3 are as follows. It is. (i) The distance between the turbine blade (31) disposed in the chamber (12) of the head body (1) and the inner wall surface of the chamber (12) is greatly different. 4 and 2
As shown in FIG. 3, d ₁ (the distance between the turbine blade and the upper and lower inner wall portions of the chamber) in the second embodiment (FIG. 3) is extremely smaller than d ₁ ′ in the first embodiment (FIG. 2). . Note that the distance between the turbine blade and the inner peripheral wall portion of the chamber is substantially the same for both (d ₂ =
d ₂ ').

(Ii) The structure of the air supply / exhaust system to the chamber (12) is greatly different. That is, in the air supply / exhaust system of the second embodiment (FIGS. 4 and 5), the air supply passage (7) is provided with compressed air at the center of the turbine blade (31) disposed in the chamber (12). It is arranged to inject a flow. In addition, the exhaust path is located at a position adjacent to the air supply port (7a) of the air supply path (7), specifically, the chamber (1).
2) Two exhaust passages having exhaust ports (8a, 9a) at upper and lower portions adjacent to the air supply port (7a) so that the pressurized air injected into the chamber (12) is not circulated (non-circulated) in the chamber (12). (8, 9). The non-circulation of the pressurized air flow in the chamber (12) is indicated by the arrow (b) in FIG.

On the other hand, the air supply / exhaust system of the first embodiment (FIGS. 2 to 3) shows a typical example applied to a conventional handpiece of this type. That is, the supply of the pressurized air into the chamber (12) is performed by an air supply passage (7) through an air supply port (7) provided on one side of the chamber (12).
Aerated via a). Further, the exhaust of the pressurized air in the chamber (12) is performed on the same side as the air supply port (7a), and a portion where the supplied pressurized air circulates in the chamber (12), specifically, FIG. As shown in FIG. 3, the air is exhausted out of the system through an exhaust path (8) via an exhaust port (8a) disposed at a distance (D) from the air supply port (7a). The fact that the pressurized air flow in the chamber (12) is of the circulating type is indicated by the arrow (a) in FIG. The arrangement of the air supply port (7a) and the exhaust ports (8a, 9a) in the second embodiment (FIG. 3) is different from the air supply port (7a) in the first embodiment (FIG. 2). The former is arranged at a position much closer to the latter than the arrangement of the exhaust ports (8a).

(Iii) The second embodiment (FIG. 3) reflecting the configuration of (ii), that is, considering the strength of the neck portion (N).
, A set of communication passages (4) is provided.

In the second embodiment (FIG. 3) of the present invention, a dental air turbine handpiece having a structure in which one set of communication passages (4) is not provided has been previously proposed by the present inventors. Handpiece with new structure (Japanese Patent Application No. Hei 6-36)
No. 404). In the handpiece having a new structure proposed by the present inventors, for example, (1) the distance (d ₁ )
Is set to 500 μm or less (a conventional product having a d ₁ ′ of, for example, 1150 μm is known), and (2) the air supply / exhaust system is configured as described above (exhaust port is an air supply port). In the case of a configuration in which the air is supplied to an adjacent part), the pressurized air supplied into the chamber (12) as in the related art does not go around the chamber (12) (non-circulation, FIG. 5). ), And immediately after the momentum is transmitted to the turbine blade, the exhaust is started. In other words, the supplied pressurized air is not circulated. The significance of this is great. In the case of the conventional orbiting type (see FIG. 3), the pressurized air suppresses the rotation of the blade in the chamber, whereas the new non-circulating type has such a disadvantage. Is eliminated. Specifically, in the handpiece of the same shape, the maximum rotational speed of the non-circular type is 47.5 × 10 ⁴ rpm, while the maximum rotational speed of the conventional circular type is 42.0 × 10 ⁴ rpm.

That is, in the dental air turbine handpiece (A) of the second embodiment, the rotational force is extremely large and the inertial rotation at the time of stoppage of operation is large. It is important to prevent suction into the interior. Further, even during operation, since the rotation speed is higher than that of the conventional one, it is important to prevent contaminants from being sucked into the head body. According to the present invention, as shown in FIG. 4, the inner wall portion of the chamber (12) of the head body (1), in particular, the inner peripheral wall portion (123) of the chamber peripheral side which has a positive pressure (+), in order to meet the above needs. From the upper and lower inner wall portions (121, 122) closer to the chamber (1).
2) A set of communication passages (41, 42) is provided at the end face of the bearing portion (2) provided at the upper and lower portions.

The present invention is capable of various modifications. FIG. 6 illustrates a dental air turbine handpiece (A) according to a third embodiment of the present invention. The major difference between the third embodiment and the second embodiment is that the receiving shaft (2) and the turbine rotor shaft (3) mounted inside the head body (1) have bearings. it is that there is a presser (C ₁ ~C ₂₎ by integrated cartridge (C). In the third embodiment, the upper communication path (41) is provided with a hole in the inner peripheral surface of the cartridge (C) and / or the head main body (1) or the bearing (2) side of the head cap (13). Alternatively, it may be formed by forming a groove. The lower communication passage (42) may be formed by forming a hole or a groove in the inner peripheral surface of the cartridge (C) and / or the head body (1).

As another embodiment of the present invention, although not shown, the structure of the bearing portion (2) is changed to that of the ball bearing mechanism using the ball bearing shown in the first to third embodiments. Needless to say, an air bearing mechanism may be used.

[0031]

The small-sized fluid-driven turbine handpiece for medical use used for dentistry and the like according to the present invention effectively prevents contamination of the inside of the head body due to contaminants such as cutting chips found in this kind of handpiece. It is something that can be done. That is, in this type of handpiece, the turbine rotor shaft continues to rotate inertially even when the air supply system is shut off during the operation of the handpiece, particularly when the operation is stopped. Then, a difference occurs in the pressure distribution (distribution of the positive pressure and the negative pressure) in the chamber, and a negative pressure is generated in the central portion of the chamber. Therefore, a turbine rotor shaft portion to which a cutting tool or the like is fixed, a bearing portion for supporting the rotor shaft, Air is sucked into the head main body together with contaminants from the head cap portion or the like, and the inside of the head is contaminated.

[0032] The present invention, the contamination problems inside the head body, focusing on the differences in the pressure distribution within the chamber at the time of stopping OPERATION, disposing a communicating passage communicating with the bearing section from the chamber into the head portion This has been solved. In addition, the contamination prevention means of the present invention is a factor that suppresses an increase in the rotational force of the turbine blade in the chamber (negative / neutral), especially in a turbine handpiece that rotates at high speed.
The positive pressure (+) is reliably applied to the bearings, etc., because the pressurized air acting as a factor) is positively guided to the bearings, and contaminants enter the head body even during operation of the handpiece. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a perspective view of a dental air turbine handpiece according to a first embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of the dental air turbine handpiece of the first embodiment of the present invention.

FIG. 3 is a sectional view taken along line II of FIG. 2;

FIG. 4 is a longitudinal sectional view of a dental air turbine handpiece according to a second embodiment of the present invention.

FIG. 5 is a sectional view taken along line II-II of FIG.

FIG. 6 is a longitudinal sectional view of a dental air turbine handpiece according to a third embodiment of the present invention.

[Explanation of symbols]

A… Dental air turbine handpiece G… Grip B… Tool H… Head 1… Head body 12… Chamber 121… Chamber upper inner wall 122… Chamber lower inner wall part 123 ... Chamber peripheral inner wall part 13 ... Head cap 14 ... Head main body lower part 2 ... Bearing part 3 ... Turbine rotor shaft 31 ... Turbine blade 32 ... … Blade support 4, 41, 42… Communication path 5… Tool shaft 51… Chuck N… Neck 6… Neck body 7… Air supply path 7 a… Supply exhaust ports 8 and 9 ......... exhaust passage 8a, 9a ......... outlet C ......... cartridge C _1, C ₂ ......... bearing retainer

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields investigated (Int. Cl. ⁷ , DB name) A61C 1/00-1/08 A61B 17/00 A61F 11/00 B23Q 5/06

Claims (6)

(57) [Claims] 1. A turbine rotor shaft (3) rotatably supported in a chamber (12) of a head body (1) of a head part (H) by a bearing part (2) disposed in the head part. (H) having a turbine blade (31), and a supply for supplying a pressurized fluid to a turbine blade (31) connected to the head (H) and disposed in the chamber (12). A passage (7) and a discharge passage (8) for discharging the pressurized fluid in the chamber (12).
(A) a small fluid-driven turbine handpiece (A) comprising: a neck portion (N) having therein: (i) the head portion (H) is a peripheral portion of a chamber (12) of the head body (1); From above and below the chamber (12)
A small fluid-driven turbine handpiece, comprising: a communication passage (4) that communicates with an end face portion of the bearing portion (2) passing outside the disposed bearing portion (2) . 2. A head body having a head portion (H) having a lower surface portion (14) and an opening (141) for projecting a lower portion of a turbine rotor shaft (3) on the lower surface portion (14). The small fluid driven turbine handpiece according to claim 1, wherein the head body (13) comprises a head kip (13) having a hole (131) in an upper part of the head body. 3. The communication path (4) is connected to an upper inner wall (121) and / or a lower inner wall (12) of the chamber (12).
2. The small fluid-driven turbine handpiece according to claim 1, wherein the small fluid-driven turbine handpiece communicates with a peripheral portion of the peripheral wall surface on the side of the inner wall portion on the side of the bearing portion on the end surface of the bearing. The communication passage (4) extends from a portion near the upper inner wall portion (121) and / or the lower inner wall portion (122) of the peripheral inner wall portion (123) of the chamber (12) to the bearing portion (2). 2. The small fluid driven turbine handpiece according to claim 1, wherein the handpiece communicates with an end face of the small fluid driven turbine handpiece. 5. The bearing according to claim 1, wherein the bearings (2) are arranged in upper and lower pairs with respect to a turbine rotor shaft (3) extending upward and downward in the chamber (12). A small fluid driven turbine handpiece as described. 6. The communication path (4) is such that one or two or more communication paths are provided from the chamber (12) to the upper and lower two sets of bearing portions (2). A small-sized fluid-driven turbine handpiece according to item 1.