JP6811013B2 - Dental handpiece and its suction prevention ring sheet - Google Patents

Description

The present invention relates to a dental hand patient and a suction prevention ring sheet thereof. Specifically, the present invention prevents foreign matter from entering the head portion due to a suckback phenomenon generated in the head portion of a dental air turbine handpiece, for example, and prevents foreign matter from entering the head portion. It relates to a dental handpiece and an anti-suction ring sheet used in the dental handpiece to prevent cross-infection between patients and operators and between patients and patients.

For example, in a dental air turbine handpiece, a tool holding member for supporting an impeller is rotatably housed in a head portion by a bearing, and the impeller is housed by air injected from an air supply port formed in the head portion. A tool holding member for holding a required tool is rotationally driven via the tool, and the air is discharged from an exhaust port formed in a head portion.

In such a dental handpiece, even if the supply of high-pressure air into the head portion is stopped, the impeller and the tool holding member continue to rotate for a while due to inertia, and this rotation forms the inside of the head portion. The air in the space is discharged to the outside, and this space becomes a negative pressure state. As a result, external air is sucked into the inside of the head portion through the gap existing in the head portion.

That is, when the rotation of the tool is stopped during dental treatment, a phenomenon (suckback phenomenon) occurs in which the patient's saliva, blood, and even the cut tooth powder are sucked into the inside of the head portion together with saliva. ..

Therefore, it is extremely important to take measures to prevent the suckback phenomenon from the viewpoint of preventing cross-infection between patients and operators and between patients and patients.

Patent Document 1 is a dental handpiece previously patented by the applicant of the present application, in which an impeller is rotatably housed in a head portion and injected from an air supply port formed in the head portion. A bearing located at the bottom of the impeller, which is configured to rotate the impeller and the required tools held by the impeller by air and discharge the air that rotates and moves with the impeller from the exhaust port formed in the head portion. A ring sheet is mounted and fixed so as to be sandwiched between the lower surface and the bottom of the head, and the ring sheet is formed so that at least the inner diameter does not contact the rotating shaft, and a plurality of notches are provided in the outer diameter direction from the inner diameter to provide the blade. When the pressure inside the head becomes positive during the rotation of the vehicle, the fan-shaped piece formed by the notch in the ring sheet bends toward the bottom of the head and is pushed open, and when the impeller stops rotating. When the pressure inside the head becomes negative, the fan-shaped piece is sucked into the head and comes into close contact with the lower surface of the bearing, and by closing the annular gap between the inner ring and the outer ring of the bearing, foreign matter enters the head. Dental handpieces configured to prevent intrusion are disclosed.

However, in the case of the dental handpiece of Patent Document 1, not only the negative pressure but also the elasticity of the ring sheet is used to bring the ring sheet into close contact with the lower surface of the bearing.
(1) The supply of high-pressure air is wasted and the ring sheet wears quickly.
(2) Due to the elasticity of the ring sheet, the impeller does not start rotating unless the pressure inside the head reaches a certain level of air pressure, and suddenly starts rotating at high speed. Therefore, centrifugal force suddenly applies to the bar chuck that holds the tool. There is a risk of hooking and the bar (tool) flying (when the play part of the bearing or the core of the bar chuck is misaligned, etc.),
(3) Since the bar chuck rotates at a rapid acceleration, an impact is applied to the bearing and retainer, shortening the life.
(4) Oil splatters due to the sudden acceleration of the bar chuck, which also shortens the bearing life.
(5) Lubrication spray oil and dirt (wear powder from retainers, etc.) tend to stay in the bearing.
It includes problems such as.

Further, in Patent Document 2, a rotary cylinder for holding a cutting tool and an impeller that is externally fixed to the rotary cylinder are housed in a head portion, and air supplied from an air supply port is applied to the impeller. In a dental cutting device that gives rotation to the impeller and discharges the air that hits the impeller from the exhaust port, the head portion is arranged at a portion facing the outer peripheral end of the impeller and is located from the central axis of the rotary cylinder. A dental cutting device having a configuration having a first gap extending in an orthogonal direction and a second gap adjacent to one end side or both end sides of the impeller with respect to the direction of the central axis and communicating with the first gap is proposed. Has been done.

However, in the case of the dental cutting device of Patent Document 2, the first gap extending in the direction orthogonal to the central axis of the rotary cylinder and the impeller with respect to the direction of the central axis are located in the portion facing the outer peripheral end of the impeller. It adopts a complicated structure that forms a second gap that is adjacent to one end side or both ends side and communicates with the first gap, and foreign matter from the gap between the inner ring and the outer ring of the bearing on the lower side of the impeller. No measures have been taken to prevent inhalation.

Japanese Patent No. 5599103 Japanese Unexamined Patent Publication No. 2003-325546

An object of the present invention is to prevent foreign substances such as saliva and blood from entering through gaps generated around a cutting tool, particularly gaps in bearings, in view of the above-mentioned prior art and the technology of Patent Document 1. It is to provide a dental handpiece that is configured to obtain and is capable of preventing cross-contamination between patients and operators and between patients and patients as described above.

Another object of the present invention is to provide a suction prevention ring sheet capable of effectively preventing cross-contamination between patients and operators and between patients and patients by attaching to the dental handpiece.

In the present invention, a tool holding member that supports an impeller is rotatably housed in a head portion by a bearing, and a required tool is rotatably accommodated through the impeller by air injected from an air supply port formed in the head portion. A dental handpiece that rotationally drives the tool holding member to be held and discharges the air from an exhaust port formed in the head portion of each bearing located in the lower portion and the upper portion of the impeller in the head portion. The tool can float on one or both of the gap areas between the lower surface and the upper surface, the lower portion of the lower surface of each bearing, the housing forming the head portion located on the upper portion of the upper surface, and each inner bottom portion of the holding bracket. The holding member is provided with one or two suction prevention ring sheets arranged in a non-contact state, and the pressure in the head portion becomes positive when the impeller rotates, so that the one or two suction prevention rings are prevented. The one or two suction prevention rings are caused by moving the ring sheet to one or both of the inner bottom portions of the housing and the holding bracket, and the pressure in the head portion becomes negative when the impeller stops rotating. The seat is moved to one or both of the lower surface direction of the lower bearing and the upper surface direction of the upper bearing to be brought into close contact with one or both of the lower surface of the lower bearing and the upper surface of the upper bearing. By closing one or both of the annular gap between the inner ring and the outer ring and the annular gap between the inner ring and the outer ring of the upper bearing, the bottom side of the head portion, one of the upper side of the head portion, or one of them is closed. The most important feature is that it is configured to prevent foreign matter from entering the head portion from both sides.

According to the dental handpiece according to the present invention, the following effects are obtained.

That is, even if the pressure inside the head becomes negative when the tool is stopped rotating, it is from the bottom side of the head part, from the upper side of the head part, or both the bottom side of the head part and the upper side of the head part. It is possible to prevent foreign matter from entering the head portion from the head.

In particular, the conventional ring sheet prevents the suction action by coming into contact with a member rotating at high speed, whereas the suction prevention ring sheet in the present invention is less likely to cause wear due to contact with the rotating member. Therefore, the durability can be improved without wasting the supply of high-pressure air.

Therefore, it is possible to prevent foreign substances such as saliva and blood from entering the head portion due to aged deterioration, and it is possible to improve safety and reliability.

In the case of the suction prevention ring sheet, since it adheres to the lower surface of the bearing due to negative pressure, even if oil adheres, there is no slit as in the case of Patent Document 1, so that the airtightness of the air increases due to the adhesion of oil. , The suction prevention ring sheet can be adhered to the bearing more strongly, and the braking effect is increased.

Since the suction prevention ring sheet is a floating type, the spray oil can wash away dirt (wear powder such as retainer) inside the bearing.

Further, the suction prevention ring sheet can prevent the turbine sound rotating at high speed from reverberating to the outside.

Furthermore, since it is possible to easily attach the suction prevention ring sheet to a dental handpiece that has not been protected against foreign matter intrusion by removing the head cap, it is possible to prevent foreign matter from entering the conventional product. Is also valid.

In particular, due to the configuration of the present invention , the lower surface or the upper surface of the seal component in which the outer peripheral portion of the suction prevention ring sheet is fixedly arranged on the inner peripheral portion of the lower outer ring of the lower bearing or on the inner peripheral portion of the upper outer ring of the upper bearing. And the gap between the housing inner bottom step portion that supports the lower end surface of the outer ring formed in the head portion, or the gap between the inner bottom step portion of the holding bracket that supports the upper end surface of the outer ring. under the configurations, from the bottom side of the head portion, or from the top side of the head portion, Ru can prevent foreign material from entering the head portion.

According to the invention of claim 2, the suction prevention ring sheet used for the dental handpiece according to the invention of claim 1 is made of an elastic material, and the thickness thereof is a dimension in the length direction of the tool holding member of the gap. By making the structure thinner, it is possible to reliably execute floating and bending at the time of positive pressure and negative pressure in the head portion, and the thickness thereof is made thinner than the dimension in the length direction of the tool holding member of the gap. Therefore, it is possible to reduce the obstruction to the air flow discharged from the bottom of the head portion.

Further, as in the invention of claim 1, by adjusting the wall thickness of the suction prevention ring sheet and the sheet width (the inner diameter is changed while the outer diameter is constant), various air turbine handpieces can be supported, and air supply air can be used. It can also cope with pressure fluctuations.

According to the invention of claim 3, the suction prevention ring sheet according to the invention of claim 2 can be made into an autoclave-compatible specification by being made of a heat-resistant material such as Teflon (registered trademark).

According to the invention of claim 4, the suction prevention ring sheet of the dental handpiece according to any one of claims 1 to 3 has a shape in which concentric convex portions are provided on the surface thereof, thereby providing a blade. It is possible to improve the braking performance when stopping the vehicle.

FIG. 1 is a schematic plan view of a dental handpiece according to a first embodiment of the present invention. FIG. 2 is a schematic enlarged perspective view of a head portion of the dental handpiece according to the first embodiment. FIG. 3 is an enlarged cross-sectional view taken along the line AA of FIG. 2, which shows the position of the suction prevention ring sheet in a positive pressure state. FIG. 4 is an enlarged cross-sectional view taken along the line AA of FIG. 2, which shows the position of the suction prevention ring sheet in a negative pressure state. FIG. 5 is a partially enlarged explanatory view showing the states of the suction prevention ring sheet with respect to the bearing lower surface of the head portion of the dental handpiece according to the first embodiment at the time of positive pressure and negative pressure. FIG. 6 is a cross-sectional view taken along the line BB of FIG. FIG. 7A is a perspective view of the suction prevention ring sheet according to the first embodiment, and FIG. 7B is a plan view of the suction prevention ring sheet according to the first embodiment. FIG. 8 is a plan view of the head portion according to the first embodiment with the impeller removed and viewed from above the head portion. FIG. 9 is an enlarged cross-sectional view of a head portion of the dental handpiece according to the second embodiment of the present invention, showing the position of the suction prevention ring sheet in a positive pressure state. FIG. 10 is an enlarged cross-sectional view of a head portion of the dental handpiece according to the second embodiment of the present invention, showing the position of the suction prevention ring sheet in a negative pressure state. FIG. 11 is a partially enlarged explanatory view showing the states of the suction prevention ring sheet with respect to the lower surface of the bearing of the head portion of the dental handpiece according to the second embodiment at the time of positive pressure and negative pressure.

The present invention is configured so as to prevent foreign substances such as saliva and blood from entering through gaps generated around a cutting tool, particularly gaps in bearings, and cross-contamination between patients and operators and between patients and patients. For the purpose of providing a dental handpiece that can be prevented, a tool holding member that supports the impeller is rotatably housed in the head portion by a bearing, and is injected from an air supply port formed in the head portion. A dental handpiece that rotationally drives a tool holding member that holds a required tool via the impeller with the air and discharges the air from an exhaust port formed in the head portion. Gap area between the lower surface and the upper surface of each bearing located at the lower part and the upper part of the impeller, and the housing forming the head portion located at the lower part of the lower surface and the upper part of the upper surface of each bearing, and each inner bottom part of the holding bracket. The lower surface of a seal component that is floatable on one or both sides and is arranged in a non-contact state with the tool holding member, and the outer peripheral portion is fixedly arranged on the inner peripheral portion of the lower or upper outer ring of each bearing. Alternatively, one or two suction prevention ring sheets facing the gap between the upper surface and the inner bottom step portion of the housing that supports the lower end surface of the outer ring or the lower end surface of the outer ring formed on the inner bottom portion of the head or the holding bracket. When the pressure in the head portion becomes positive during the rotational operation of the impeller, the central portion side bends while keeping the outer peripheral portions of the one or two suction prevention ring sheets facing the gap, and the central portion side bends. The one or two suctions are pressed by one or both of the inner bottoms of the housing and the holding bracket to bring them into close contact with each inner bottom , and the pressure inside the head becomes negative when the impeller stops rotating. The prevention ring sheet is moved in one or both of the lower surface direction of the lower bearing and the upper surface direction of the upper bearing while the outer peripheral portion thereof faces the gap, and the lower surface of the lower bearing and the upper bearing of the prevention ring sheet are moved. The head is brought into close contact with one or both of the upper surfaces to close one or both of the annular gap between the inner ring and the outer ring of the lower bearing and the annular gap between the inner ring and the outer ring of the upper bearing. This was realized by making it possible to prevent foreign matter from entering the head portion from one or both of the bottom side of the portion and the upper side of the head portion.

The dental handpiece and the suction prevention ring sheet according to the embodiment of the present invention will be described in detail below with reference to the drawings.

The dental handpiece 1 and the suction prevention ring sheet 41 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 8.

As shown in FIGS. 1 and 2, the dental handpiece 1 according to the first embodiment of the book is composed of a head portion 2 and a main body portion 3, and a dental treatment device (not shown) is behind the main body portion 3. ) Is provided with a hose joint 4.

The compressed air supplied from the dental treatment device (not shown) is configured to be supplied into the head portion 2 from the air supply port 14 (see FIG. 6) in the head portion 2 via the hose joint 4. ..

Next, the head portion 2 will be described in detail with reference to FIG.

The head portion 2 includes a housing 5, and an impeller 11 is housed in the housing 5, a tool that supports the impeller 11 and the impeller 11 and a tool (not shown) is mounted from below. The holding member 12 is rotationally driven by the air injected from the air supply port 14 of the air supply pipeline 13 formed in the main body 3, and the air flowing with the rotation of the impeller 11 is formed in the housing 5. It is configured to be exhausted from the exhaust port 15 through the exhaust pipe line 16 formed in the main body 3.

At this time, the flowing air flows into the exhaust pipe line 16 and at the same time is discharged to the atmosphere through the gap of the push cap 21 and the gap 23 of the bottom 22 of the housing 5.

In this case, on the bottom 22 side, the air passes through the annular gap S1 between the inner ring 24a and the outer ring 24b of the bearing 24 mainly made of stainless steel, which is located below the impeller 11. It is discharged through the gap 23 of the bottom portion 22.

A suction prevention ring made of a floating elastic material and a heat-resistant material as shown in FIGS. 7A and 7B, which will be described in detail later, on an inner bottom portion 5a located below the bearing 24 in the housing 5. The seat 41 is arranged.

The bearing 24 includes a ball 24c and a retainer 24d in addition to the inner ring 24a and the outer ring 24b. The upper bearing 29 also has the same structure as the bearing 24.

The impeller 11 has a structure in which a required number of blades are projected in the radial direction of the tool holding member 12 on which a tool (not shown) can be attached and detached as a rotation axis.

The tool holding member 12 has a cartridge structure in which the bearing 24 and the upper bearing 29 are press-fitted so as to sandwich the impeller 11.
The tool holding member 12 has a structure in which a holding portion (not shown) is opened and closed by pushing the push cap 21 against the elastic force of the spring 30 from above, and the tool can be attached and detached.

An O-ring 26 is mounted between the bearing 24 and the housing 5, and an O-ring 27 is mounted between the bearing 29 and the holding bracket 31 that covers the bearing 29.

FIG. 8 shows a state in which the head cap 28, the holding bracket 31, the impeller 11, the bearing 24, the bearing 29, and the tool holding member 12 are removed from the head portion 2 and viewed from above the head portion 2.

Next, the bearing 24 and the suction prevention ring sheet 41 will be described in more detail with reference to FIGS. 3 and 5.

As shown in an enlarged view in FIG. 5, the bearing 24 includes the inner ring 24a, the outer ring 24b, the ball 24c, and the retainer 24d, and the outer peripheral portion 32a is provided on the inner peripheral portion of the lower portion of the outer ring 24b of the bearing 24. A thin annular shield body 32 made of stainless steel with a step, which is a seal component fixed in an arrangement orthogonal to the inner ring 24a with respect to the provided seal component mounting recess 24e, and the shield body 32 are attached to the outer ring 24b. It also has a thin annular retaining ring 33 made of stainless steel that is fastened to the lower sealing component mounting recess 24e.

The shield body 32 is formed in a dish shape in which the central portion 32b has a step lower than that of the outer peripheral portion 32a, and the inner diameter portion inside the central portion 32b is set to a size that does not contact the outer periphery of the inner ring 24a.

Further, the retaining ring 33 has a flat thin annular shape and a narrow shape that fixes and supports only the outer peripheral portion 32a of the shield body 32 with respect to the sealing component mounting recessed portion 24e.

The suction prevention ring sheet 41 arranged on the inner bottom portion 5a of the housing 5 located below the bearing 24 has a central hole portion 42 having a size that does not contact the tool holding member 12, and has an outer diameter thereof. The size is slightly smaller than the inner diameter of the inner bottom portion 5a of the housing 5, and the inner bottom portion 5a, the lower surface of the inner ring 24a of the bearing 24, the shield body 32, and the retaining ring 33 respond to pressure fluctuations in the head portion 2. The gap region S2 between the housing and the lower surface of the housing can be floated (floating up and down in the state shown in FIG. 3).

Next, the suction prevention ring sheet 41 will be described in more detail with reference to FIG.

The material of the suction prevention ring sheet 41 is preferably a Teflon (registered trademark) material which is made of an elastic material and can withstand heat even when autoclaved (sterilized by a sterilizer), but is limited to a Teflon (registered trademark) material. It's not a thing.

Further, the wall thickness dimension of the suction prevention ring sheet 41 can be any wall thickness dimension as long as it bends in response to fluctuations in the air pressure in the head portion 2.

Next, the action of the dental handpiece 1 and the suction prevention ring sheet 41 of the first embodiment to prevent foreign matter from entering the head portion 2 and the effect will be described mainly with reference to FIGS. 3 and 4.

In the dental handpiece 1 and suction prevention ring sheet 41 of the first embodiment, when air is supplied from the intake pipe line 13 through the intake port 14, the impeller 11 and the tool (not shown) are injected by the air injection. ) Is rotationally driven to enable the dental handpiece 1 to perform a treatment of the trunk, and the inside of the head portion 2 is in a positive pressure state, whereby the suction prevention ring sheet 41 is moved. As shown in FIGS. 3 and 5, the housing 5 is pressed against the inner bottom portion 5a and is in close contact with the inner bottom portion 5a.

On the other hand, when the above-mentioned air injection is stopped in the dental handpiece 1 and the suction prevention ring sheet 41, the impeller 11 continues to rotate for a certain period of time due to inertia.

While the impeller 11 continues to rotate due to this inertia, the air flow accompanying the rotation of the impeller 11 is discharged through the exhaust port 15 and the exhaust pipe line 16, but at the same time, near the air supply port 14 ( In the vicinity), the pressure decreases from "positive pressure" to "same pressure (relative to atmospheric pressure)" and from "same pressure" to "negative pressure", and the entire inside of the head portion 2 changes to a negative pressure state. ..

According to such a change in pressure from the positive pressure to the negative pressure in the head portion 2, a suction force acts on the suction prevention ring sheet 41 toward the lower surface of the bearing 24, and as a result, the suction prevention ring sheet 41 As shown in FIGS. 4 and 5, the bearing 24 moves while floating toward the lower surface of the bearing 24, closes the annular gap S1 and is in close contact with the lower surface of the bearing 24.

As a result, foreign substances such as saliva, blood, and cut tooth powder of the patient are prevented from entering the head portion 2 from the bottom 22 side of the head portion 2, and the dental handpiece 1 is used for treatment. It is possible to accurately prevent cross-contamination between patients / operators and between patients / patients, which tends to occur as a result.

More specifically, according to the dental handpiece 1 and the suction prevention ring sheet 41 of the first embodiment, the suction prevention ring sheet 41 does not come into contact with the tool holding member 12, so that the suction prevention ring sheet 41 is durable. The sex can be improved to each stage.

Therefore, it is possible to prevent an increase in invasion of foreign substances such as saliva and blood into the head portion 2 caused by aged deterioration, and it is possible to improve safety and reliability.

Further, in the case of the dental handpiece 1 and the suction prevention ring sheet 41 in the first embodiment, since they are in close contact with the lower surface of the bearing due to negative pressure, even if oil adheres, the airtightness increases due to the adhesion of the oil. Therefore, the suction prevention ring sheet 41 can be more strongly adhered to the lower surface of the bearing 24 to increase the braking effect, and since the suction prevention ring sheet 41 is a floating type, spray oil can easily enter the inside of the bearing 24. The suction prevention ring sheet 41 can prevent the turbine sound rotating at high speed from reverberating to the outside, and the suction prevention ring sheet 41 is made of an elastic material, so that the head portion 2 has positive pressure and negative pressure. It has the effect of being able to reliably perform floating and bending.

Further, by forming the suction prevention ring sheet 41 with a heat-resistant material such as Teflon (registered trademark), it is possible to make the specifications compatible with autoclave.

Furthermore, according to the first embodiment, the head cap 28 is removed even for a dental handpiece that has not been protected against foreign matter intrusion, and the suction prevention ring sheet 41 can be easily attached to a predetermined portion in the head portion 2. Since it can be attached to a conventional product, it is also extremely effective as a measure to prevent foreign matter from entering the conventional product.

Next, the dental handpiece 1 and the suction prevention ring sheet 41A according to the second embodiment of the present invention will be described with reference to FIGS. 9 to 11.

In the dental handpiece 1 and the suction prevention ring sheet 41A according to the second embodiment, the same elements as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The dental handpiece 1 and the suction prevention ring sheet 41A according to the second embodiment have substantially the same basic configurations as those in the first embodiment, but the external dimensions of the suction prevention ring sheet 41A are the same as those of the first embodiment. The lower surface of the retaining ring 33 and the lower surface of the retaining ring 33 in which the outer peripheral portion of the suction prevention ring sheet 41A is fixedly arranged in the sealing component mounting recessed portion 24e below the outer ring 24 of the bearing 24. It is characterized in that it faces the gap S3 between the inner bottom step portion 5b that supports the lower end surface of the outer ring 24 formed on the outside of the inner bottom portion 5a.

According to the dental handpiece 1 and the suction prevention ring sheet 41A according to the second embodiment, the suction prevention ring sheet is obtained when the inside of the head portion 2 is in a positive pressure state as in the case of the first embodiment. As shown in FIGS. 9 and 11, the central portion of 41A bends while the outer peripheral portion thereof faces the inside of the sealing component mounting recessed portion 24e, and is pressed by the inner bottom portion 5a of the housing 5 to the inner bottom portion 5a. It will be in close contact.

On the other hand, when the inside of the head portion 2 is in a negative pressure state, a suction force in the lower surface direction of the bearing 24 acts on the suction prevention ring sheet 41A.

As a result, as shown in FIGS. 10 and 11, the suction prevention ring sheet 41A moves while floating toward the lower surface of the bearing 24 while facing the outer peripheral portion thereof into the sealing component mounting recessed portion 24e. It is in close contact with the lower surface of the bearing 24.

That is, the central portion side of the suction prevention ring sheet 41A closes the annular gap S1 and is in close contact with the lower surface of the inner ring 24a.

As a result, foreign substances such as saliva, blood, and cut tooth powder of the patient are prevented from entering the head portion 2 from the bottom 22 side of the head portion 2, and the dental handpiece 1 is used for treatment. It is possible to accurately prevent cross-contamination between patients / operators and between patients / patients, which tends to occur as a result.

According to the dental handpiece 1 and the suction prevention ring sheet 41A according to the second embodiment, the same effect as that of the first embodiment can be exhibited.

Further, the suction prevention ring sheet 41A is formed of an elastic material in particular, and its thickness is thinner than the dimension of the tool holding member 12 of the gap S3 in the length direction, so that the positive pressure in the head portion 2 is formed. At times, it is possible to reliably execute floating and bending at the time of negative pressure, and by reducing the thickness as described above, it is also possible to reduce the obstruction to the air flow discharged from the bottom of the head portion 2. it can.

In this case, since the suction prevention ring sheet 41A may have a small vertical movement distance, the thickness thereof is made equal to or less than the gap size (for example, 0.15 mm) between the retaining ring 33 and the inner bottom step portion 5b. As a result, it is possible to reliably close or release the annular gap S1 between the outer ring 24b and the inner ring 24a of the bearing 24 according to the change in the pressure in the head portion 2.

Next, further expansion examples of the dental handpiece 1 and the suction prevention ring sheets 41 and 41A according to the first and second embodiments will be outlined.

In the dental handpiece 1 according to the first embodiment described above, the suction prevention ring sheet 41 is moved toward the inner bottom portion of the housing 5, and the pressure inside the head portion 2 becomes negative when the impeller 11 stops rotating. As a result, the suction prevention ring sheet 41 is moved toward the lower surface of the lower bearing 24 to be brought into close contact with the lower surface of the bearing 24, and an annular gap S1 between the inner ring 24a and the outer ring 24b of the bearing 24 is formed. By closing it, it is possible to prevent foreign matter from entering the head portion 2 from the bottom side of the head portion 2, but instead of this, the upper surface of the bearing 29 located at the upper part of the impeller 11 and this The structure is provided with the suction prevention ring sheet (not shown) which is floatable in the gap region between the holding bracket 31 located at the upper part of the bearing 29 and the inner bottom portion and is arranged in a non-contact state with the tool holding member 12. You can also do it.

With this configuration, the pressure inside the head portion 2 becomes positive during the rotational operation of the impeller 11, so that the suction prevention ring sheet 41 is suppressed and moved toward the inner bottom portion of the bracket 31, and the impeller When the rotation of 11 is stopped, the pressure in the head portion 2 becomes negative, so that the suction prevention ring sheet 41 is moved toward the upper surface of the bearing 29 and brought into close contact with the upper surface of the bearing 29, and the inner ring and the outer ring of the bearing 29 are brought into close contact with each other. By closing the annular gap between the two, it is possible to prevent foreign matter from entering the head portion 2 from the upper side of the head portion 2.

Further, using two suction prevention ring sheets 41, between the bearing 24 and the inner bottom portion of the housing 5, and the upper surface of the bearing 29 and the inner bottom portion of the holding bracket 31 located on the upper portion of the bearing 29. If the suction prevention ring sheets 41 are arranged on both sides of the head portion 2, foreign matter can be prevented from entering the head portion 2 from the bottom side of the head portion 2 and from the upper side of the head portion 2 into the head portion 2. It is possible to exert both effects of preventing foreign substances from entering the head portion 2, and it is possible to more effectively prevent foreign substances such as saliva and blood from entering the head portion 2, which is safe and reliable. Can be further improved.

Further, in the case of the dental handpiece 1 according to the second embodiment described above, the pressure inside the head portion 2 becomes negative, so that the outer peripheral portion of the suction prevention ring sheet 41A faces the gap S3. As it is, the suction prevention ring sheet 41A is moved toward the lower surface of the bearing 24 provided with the shield body 32 and the retaining ring 33 to be brought into close contact with the lower surface of the bearing 24, and the annular shape between the inner ring 24a and the outer ring 24b of the bearing 24 is maintained. By closing the gap S2, foreign matter is prevented from entering the head portion 2 from the bottom side of the head portion 2, but instead of this, the bearing 24 located above the impeller 11 is used. The bearing 29 has a similar structure and is floatable in a gap region between the upper surface of the bearing 29 and the inner bottom portion of the holding bracket 31 located on the upper portion of the bearing 29, and is arranged in a non-contact state with the tool holding member 12. The suction prevention ring sheet (not shown) may be provided.

With this configuration, the pressure inside the head portion 2 becomes positive during the rotational operation of the impeller 11, so that the suction prevention ring sheet 41A is suppressed and moved toward the inner bottom portion of the bracket 31, and the impeller When the rotation of 11 is stopped, the pressure in the head portion 2 becomes negative, so that the suction prevention ring sheet 41A moves toward the upper surface of the bearing 29 and is brought into close contact with the upper surface of the bearing 29, and the inner ring and the outer ring of the bearing 29 are brought into close contact with each other. By closing the annular gap between the two, it is possible to prevent foreign matter from entering the head portion 2 from the upper side of the head portion 2.

Further, using two suction prevention ring sheets 41A, between the bearing 24 and the inner bottom portion of the housing 5, and the upper surface of the bearing 29 and the inner bottom portion of the holding bracket 31 located on the upper portion of the bearing 29. If the suction prevention ring sheets 41A are arranged on both sides of the head portion 2, foreign matter can be prevented from entering the head portion 2 from the bottom side of the head portion 2 and from the upper side of the head portion 2 into the head portion 2. It is possible to exert both effects of preventing foreign substances from entering the head portion 2, and it is possible to more effectively prevent foreign substances such as saliva and blood from entering the head portion 2, which is safe and reliable. Can be further improved.

In addition to the above cases, the suction prevention ring sheets 41 and 41A may have a shape in which a plurality of concentric convex portions having predetermined intervals are provided on the surface thereof, or the surface thereof may have a central side to an outer peripheral portion. It is also possible to form a shape in which a plurality of convex portions are provided in a radial shape.

By providing a plurality of concentric convex portions on the surfaces of the suction prevention ring sheets 41 and 41A, the outer diameter side corner portion (small R chamfered) of the inner ring of the bearing serving as the contact portion is on the outer diameter side. The concentric convex portions of the suction prevention ring sheets 41 and 41A are in a surface contact state so as to wrap around the corner portions, whereby the braking performance when the impeller 11 is stopped can be improved.

The present invention is not limited to dental handpieces, but in various medical devices that use air to drive tools, the cause of infection due to foreign matter entering the head of the device can be reduced, and medical treatment can be performed. It can be widely used as a safety improvement measure.

1 Dental handpiece 2 Head 3 Main body 4 Hose joint 5 Housing 5a Inner bottom 5b Inner bottom 11 Impeller 12 Tool holding member 13 Air supply line 14 Air supply port 15 Exhaust port 16 Exhaust line 21 Push cap 22 Bottom 23 Gap 24 Bearing 24a Inner ring 24b Outer ring 24c Ball 24d Retainer 24e Seal component mounting recess 26 O-ring 27 O-ring 28 Head cap 29 Bearing 30 Spring 31 Retaining bracket 32 Shield body 32a Outer circumference 32b Central part 33 Retaining ring 41 Ring sheet 41A Suction prevention ring sheet 42 Central hole S1 Circular gap S2 Gap area S3 Void

Claims (4)

A tool holding member that supports the impeller is rotatably housed in the head portion by a bearing, and a tool holding member that holds a required tool via the impeller by air injected from an air supply port formed in the head portion. A dental handpiece that rotationally drives a member and discharges the air from an exhaust port formed in a head portion.
Within the head portion, the lower surface and the upper surface of each bearing located at the lower part and the upper part of the impeller, and the housing forming the head portion located at the lower part of the lower surface and the upper part of the upper surface of each bearing, and each inner bottom portion of the holding bracket. The whole is floatable in one or both of the gap regions between the bearings, and is arranged in a non-contact state with the tool holding member, and the outer peripheral portion is fixedly arranged on the inner peripheral portion of the lower or upper outer ring of each bearing. One or two facing the gap between the lower surface or upper surface of the seal component and the inner bottom surface of the head or the inner bottom step portion of the housing that supports the lower end surface of the outer ring or the lower end surface of the outer ring formed on the holding bracket. Equipped with a suction prevention ring sheet
When the pressure inside the head portion becomes positive during the rotational operation of the impeller, the central portion side bends while keeping the outer peripheral portions of the one or two suction prevention ring sheets facing the gap, and the housing and the restraining portion are suppressed. Pressed by one or both of the inner bottoms of the bracket to bring them into close contact with each inner bottom.
When the impeller stops rotating, the pressure inside the head becomes negative, so that the one or two suction prevention ring sheets are placed in the lower surface direction of the lower bearing with the outer peripheral portion facing the gap. Moves to one or both of the upper bearings in the upper surface direction to bring them into close contact with one or both of the lower surface of the lower bearing and the upper surface of the upper bearing, and an annular shape between the inner ring and the outer ring of the lower bearing. By closing one or both of the gap and the annular gap between the inner ring and the outer ring of the upper bearing, foreign matter can enter the head portion from the bottom side of the head portion and one or both of the upper side of the head portion. A dental handpiece that is configured to be preventable. The suction prevention ring sheet for a dental handpiece according to claim 1 , wherein the suction prevention ring sheet is made of an elastic material, and the thickness thereof is thinner than the dimension in the length direction of the tool holding member of the gap. The suction prevention ring sheet for a dental handpiece according to claim 2 , wherein the suction prevention ring sheet is made of a heat-resistant material. The suction prevention ring sheet for a dental handpiece according to any one of claims 2 to 3 , wherein the suction prevention ring sheet has a shape in which concentric convex portions are provided on the surface thereof.

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