JPH01110358A - Dental handpiece - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a dental end piece used when cutting teeth, crowns, etc. with a dental bur.

[Prior Art] As shown in FIG. 3, for example, a conventional handpiece of this type has a holder (not shown) that is rotatably driven inside the main body 1, and the dental bur A is rotated by this holder. The shank B is held and rotated, and the teeth T are cut by the blade C. In addition, a nozzle 2 is installed in the main body 1, and by spraying cooling water from the nozzle 2 onto the blade C and teeth T, the blade C and the teeth T are cooled. This prevents wear and tear and reduces patient pain caused by stimulation of tooth nerves by cutting heat.

[Problem 1 with Prior Art However, if the cooling water is sprayed from the nozzle 2, it is difficult to spray the cooling water directly onto the cutting area. In particular, when the cutting area is deep, the cooling water hardly reaches the tip of the blade C and the deep part of the cutting area, so there is a problem that a sufficient cooling effect cannot be obtained.

[Technology 1 related to the previous application] Therefore, this applicant first published a dental handpiece that can obtain a sufficient cooling effect.
No. 97), the dental handpiece according to the earlier application uses a dental bur having a cooling water hole opened at the tip surface of the blade part as the dental bur,
A cooling water passage is formed inside the main body, and a cooling water inflow hole is formed in the holder to which the shank of the dental bur is attached, and the cooling water is supplied to the dental bur through the cooling water passage and the inflow hole. The cooling water is fed into the cooling water hole and spouted from the opening at its tip.

According to this dental handpiece, cooling water can be jetted from the tip surface of the blade of the dental bur, so even if the cutting area is deep, cooling water can be sprayed directly onto the tip of the blade and the cutting area. Therefore, the cooling effect can be greatly improved.

[Problems to be Solved by the Invention] However, in the dental handpiece according to the above-mentioned Hikari application, when the holder is supported by, for example, a ball bearing, there is a risk that the inner and outer rings and steel balls thereof will rust early. there were. That is, since the holder that holds the dental bur usually rotates at a high speed of about 300,000 revolutions, it is difficult to bring the wall surface of the main body where the cooling water passage opens into contact with the wall surface of the holder where the inflow channel opens. You can't do that and you have to keep them apart. Therefore, a portion of the cooling water sent from the cooling water passage flows into the main body from the opening of the cooling water passage. When this flowing cooling water enters the ball bearing that supports the holder, it evaporates due to the heat generated by the ball bearing. As a result, the ball bearing is surrounded by an atmosphere of water vapor, causing early rusting6.And when the ball bearing rusts, the rotation of the holder is inhibited, leading to the problem that it cannot rotate at high speed.

[Objective of the Invention 1 This invention was made to solve the above problem, and it is possible to improve the cooling effect as well as to improve the cooling effect.
An object of the present invention is to provide a dental handpiece that can prevent cooling water from entering a rotating support part such as a ball bearing.

[Structure 1 of the Invention] In order to achieve the above object, the present invention provides a wall surface facing the bottom side space of the storage hole whose one end is connected to a cooling water supply source and whose other end is partitioned by a holder, inside the main body. A cooling water passage is formed inside the holder, one end of which communicates with the mounting hole, and the other end of which is open to the outer surface facing the space. An annular compressed air introduction gap centered around the rotation axis of the holder is formed between the faces of the holding body, with the cooling water passage and the space side opening of the inflow hole located inside the gap, and the compressed air is An air introduction passageway for supplying compressed air to the introduction gap is formed in the main body.

[Embodiment 1] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 is a partially omitted longitudinal sectional view of an embodiment of the present invention, and in the figure, reference numeral 11 indicates the main body.

This main body 11 includes a grip portion 12 and a cap 13. The gripping part 12 has a rod shape to be gripped by an operator, and a storage hole 14 is formed in the distal end of the gripping part 12, passing through from the lower end surface to the upper end surface. This storage hole 1
The cap 13 is screwed and fixed to the upper end of the storage hole 14, thereby sealing the upper end of the storage hole 14. In addition, the rotation axis is arranged inside the storage hole 14.
A holder 15 is rotatably provided and is aligned with the center line of the holder 15.

This holding body 15 includes a rotating body 16 and a collet chuck 17.
It is equipped with

The rotating body 16 is rotatably supported on the inner peripheral surface of the storage hole 14 via ball bearings 18 and 19, and has a large number of blades 16a formed on its outer peripheral surface. This blade 16a has a supply hole 1 formed inside the grip part 12.
Compressed air is blown through the cylinder 2&, which allows the rotating body 16 to rotate.

In addition, the code|symbol 12b is a discharge hole for discharging compressed air.

Furthermore, a through hole 20 is formed in the center of the rotating body 16 and extends along the center line thereof. A tapered hole portion 20a whose diameter gradually decreases toward the top is formed approximately at the center of the through hole 20, and a sleeve 21 is fitted and fixed to the lower end of the through hole 20 in a fluid-tight manner.

On the other hand, the collet chuck 17 is for holding the shank B of the dental bur A, and the collet chuck 17 is for holding the shank B of the dental bur A.
It is inserted so that it can move freely in the vertical direction. This collet chuck 17 has a mounting hole 22 formed inside thereof extending upward from the lower end surface, a tapered part 17a corresponding to the tapered hole part 20a on the outer periphery of the lower end, and a mounting hole 22 extending from the outer periphery. A plurality of slits 23 extending up to 22 are formed. Therefore, when the tapered portion 17a is press-fitted into the tapered hole portion 20a, the diameter of the attachment hole 22 is reduced, so that the shank B inserted into the attachment hole 22 can be firmly held. Further, a coil spring 24 is provided between the collet chuck 17 and the sleeve 21 in order to press and fit the tapered portion 17a into the tapered hole portion 20a.

Note that the cap 13 is provided with a push button 25, and when the push button 25 is pushed down, the fret chuck 17 is pushed down, thereby causing the tapered portion 17 to be pushed down.
The fitting between the taper hole 20a and the taper hole 20a is released. Further, a return spring 26 is provided between the push button 25 and the cap 13 to return the pressed push button 25 to its original position.

Also, inside the main body 11, there is a passage 2 for flowing cooling water.
7 is formed. One end of this passage 27 is connected to a cooling water supply source (not shown), and the other end is connected to a push button 2.
It is connected to a communication hole 28 formed inside the 5. This communication hole 28 is opened at the tip end surface of a protrusion 29 formed at the center of the lower end surface of the push button 25 . On the other hand, an inflow hole 30 leading to the attachment hole 22 is formed in the center of the upper end surface of the collet chuck 17 facing the communication hole 28, and the tip of the protrusion 29 enters into this inflow hole 30. Therefore, the cooling water supplied through the passage 27 passes through the communication hole 28 and the inflow hole 30 to the attachment hole 22.
sent inside. The cooling water sent into the attachment hole 22 passes through a cooling water hole formed in the dental bur A and is injected from its tip opening.

In addition, in order to cope with the case where a dental bur without a cooling water hole is used, in this handpiece, a cooling water supply hole 31 and a cooling air supply hole 32 are formed inside the grip part 12, respectively. Both of them are open at the lower surface of the tip of the gripping part 12.

By the way, as mentioned above, since the holder 15 rotates at a high speed of 300,000 rotations, the upper end surface of the collet chuck 17 and the lower end surface of the push button 25 cannot be brought into contact when the fret chuck 17 rotates. Therefore, a portion of the cooling water flowing out from the communication hole 28 flows into the space S defined by the lug 25, the holder 15, and the ball bearing 18 inside the insertion hole 14. When this flowing cooling water enters between the inner ring 18a and outer ring 18b of the ball bearing 18, the inner and outer rings 18a.

The ball bearing 18 is evaporated by the rolling friction heat between the steel ball 18b and the steel ball 18c, and the ball bearing 18 is surrounded by an atmosphere of water vapor. Of course, the same applies to the ball bearing 19. As a result, there is a risk that the ball bearings 18 and 19 will rust early and the high speed rotation of the holder 15 will be inhibited.

Therefore, in the dental handpiece of the present invention, compressed air is used to prevent the cooling water from flowing out to the ball bearing 18 side.

That is, an annular convex portion 33 is formed on the outer peripheral surface of the rotating body 16 located above the ball bearing 18 . The annular convex portion 33 has an outer diameter slightly smaller than the inner diameter of the storage hole 14 . As a result, the annular convex portion 3
A narrow annular gap 34 is formed between the outer circumferential surface of the storage hole 3 and the inner circumferential surface of the storage hole 14 facing thereto. This gap 34 includes an air introduction passage 3 formed in the main body 11.
Compressed air is sent from 5.
A part of the compressed air supplied into the gap 34 blows out from the upper end of the gap 34, flows into the cooling water hole of the dental bur A through the inflow hole 3o and the attachment hole 22, and flows into the cooling water hole of the dental bur A. The other part of the water is ejected from the opening of the gap 34 along with the cooling water, and the other part is ejected from the lower end of the gap 34 and the inner ring 1 of the ball bearing 18.
It passes between the outer ring 8a and the outer ring 18b and is discharged from the exhaust hole 12b.

In this way, since the annular opening 34 through which compressed air is supplied is formed between the outer circumferential surface of the annular convex portion 33 of the rotating body 16 and the inner circumferential surface of the storage hole 14, the space S is It is divided into an upper space S1 in which the communication hole 28 and the inflow hole 29 are open, and a lower space S2 facing the ball bearing 18, and the circulation of cooling water is blocked between the inner space S and the outer space 82 by compressed air. Therefore, cooling water can be prevented from entering into the ball bearings 18, 19. Furthermore, since air is in contact with the rotating body 16, high-speed rotation of the rotating body 16 is not inhibited.

Note that the gap 34 and the compressed air supplied therein are for preventing cooling water from passing through.
It is desirable to make the gap 34 as narrow as possible;
．． It is preferable to set the pressure to about 0.05 mm to O, OO1 ma+, and the pressure of the compressed air is preferably higher than the pressure of the cooling water.

Next, other embodiments of the invention will be described.

Note that the same parts as in the above embodiment are given the same reference numerals, and the explanation thereof will be omitted.

The dental handpiece shown in Fig. 2 not only blocks cooling water using the gap and the compressed air supplied there, but also has a bearing function. The outer ring member 3 is provided on the inner peripheral surface of the storage hole 14.
6 is fixed in position. This outer ring member 36 is made of porous sintered metal, ceramic, etc., and has an annular recess 36a formed on its outer circumference, and an annular protrusion 36b formed at the upper end of its inner circumference. There is.

Moreover, the surface layer of the outer ring member 36 forming the outer surface other than the surface that partitions the recess 36&, the lower end surface of the annular projection 36b, and the inner circumferential surface below the annular projection 36b is impregnated to prevent air from passing through. has been done. Therefore, the compressed air supplied from the air introduction passage 35 into the recess 36a passes through the inside of the outer ring member 36 and reaches the annular protrusion 36.
The water is ejected from the L-shaped surface formed by the lower end surface of b and the inner circumferential surface below it.

On the other hand, an inner ring member 37 is fixed to the outer peripheral surface of the upper end portion of the rotating body 16. The upper end surface of this inner ring member 37 faces the lower end surface of the annular projection 36b of the outer ring member 36, and the inner ring member 37
The outer circumferential surface of the outer ring member 36 faces the inner circumferential surface of the outer ring member 36. A gap 38 at a constant interval is formed between these opposing surfaces.

In the dental handpiece configured in this way,
When compressed air is sent from the air introduction passage 35 to the recess 36a, the compressed air passes through the outer ring member 36 and is ejected into the gap 38. Therefore, it is possible to prevent the cooling water from flowing out toward the blades 16a and the ball bearing 19. can. Moreover, the compressed air blown into the gap 38 supports the inner ring member 37 with respect to the outer ring member 36 in a non-contact state. Therefore, the ball bearing 1 in the above-described embodiment
8 is no longer necessary, the number of parts can be reduced, and as a result, the handpiece can be made smaller.

In the above embodiment, the holding body 15 is rotated by compressed air, but it may be rotated by other means such as a motor.

[Advantageous Effects of the Invention 1] As explained above, the present invention provides a dental handpiece in which a cooling water passage is formed inside the main body, and an inflow hole communicating with the mounting hole is formed inside the holder. The cooling water supplied from the cooling water passage is sent into the mounting hole through the inflow hole, and this cooling water is ejected from the cooling water hole formed in the dental bur, so that the blade part and cutting In addition to being able to directly cool the area and therefore greatly improving the cooling effect, there is also an annular shape centered around the rotation axis of the holder between the opposing surfaces of the main body and the holder. A compressed air introduction gap is formed such that the cooling water passage and the space side opening of the inflow hole are located inside the gap, and an air introduction passage for supplying compressed air to the compressed air introduction gap is formed. Since it is formed in the main body, effects such as being able to prevent cooling water from entering the support portion that rotatably supports a holding body such as a ball bearing can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a partially omitted longitudinal sectional view showing an embodiment of the present invention;
FIG. 2 is a partially omitted vertical sectional view showing another embodiment of the present invention, and FIG. 3 is a partially omitted side view showing an example of a conventional dental piece. 11... Main body, 14... Storage hole, 15... Holder, 18.19... Ball bearing, 22... Mounting hole, 27... Cooling water passage, 28... Communication Hole, 30
... Inflow hole, 34.38 ... Compressed air introduction gap,
35...Air introduction passage.

Claims (1)

[Claims] The main body has a storage hole formed therein with one end open, and a holder rotatably supported by the inner circumferential surface of the storage hole of the main body and rotated by a rotational drive source. A dental handpiece in which a mounting hole into which the shank of a dental bur inserted from the opening of the storage hole is inserted is formed with its axis aligned with the axis of the holder, inside the main body, A cooling water passage is formed, one end of which is connected to a cooling water supply source, the other end of which is open to a wall surface facing the bottom side space of the storage hole defined by the holding body, and one end is connected to the inside of the holding body. An inflow hole is formed which communicates with the mounting hole and whose other end opens to the outer surface facing the space, and further has an inlet hole between mutually opposing surfaces of the main body and the holder, centered around the rotating ring line of the holder. In order to supply compressed air to the compressed air introduction gap by forming an annular compressed air introduction gap such that the cooling water passage and the space-side opening of the inflow hole are located inside the gap; A dental handpiece characterized in that an air introduction passage is formed in the main body.