SEAL DEVICE

Provided is a seal device, which can reliably prevent leakage of substances from a gap in a coupling portion for two flow paths while improving ease of operation at the time of coupling the two flow paths to each other and decoupling the two flow paths from each other. The seal device includes: a first flow path (16A) which allows substances to pass therethrough; a second flow path (16B) separably coupled to the first flow path (16A); a sealing member (52), which has elasticity, and is held in a gap in a coupling portion (15) between the first flow path (16A) and the second flow path (16B); and a movable member (30) that closes the gap in the coupling portion (15) by deforming the sealing member (52) when the first flow path (16A) and the second flow path (16B) are to be coupled to each other.

TECHNICAL FIELD

The present invention relates to a seal device that prevents leakage of substances from a gap between flow paths separably coupled to each other.

BACKGROUND ART

In general, seal devices that prevent leakage of substances such as liquid or gas have been known.

For example, in the seal device of this type, as illustrated inFIG.13, a peripheral groove205is formed in an outer peripheral distal end portion of one flow path member200side of two flow path members200and201that function as supply passages for substances and are separably coupled to each other, and an annular rubber sealing member206called an O-ring is held in the peripheral groove205. When the flow path members200and201are to be coupled to each other, the O-ring208comes into elastic contact with the flow path members200and201to close a gap S in a coupling portion210, thereby preventing leakage of substances from the gap S in the coupling portion210.

Further, the following seal device has been known. Specifically, in a dental handpiece having separable flow paths, a plurality of O-rings are arranged in parallel in a coupling portion for flow paths, thereby preventing leakage of air or liquid from a gap in the coupling portion (see, for example, Patent Literature 1).

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

Incidentally, when the above-mentioned seal device is applied to a flow path to which powdery solid fine particles having a particle diameter of from about 0.1 μm to about 10 μm are supplied, a problem in that the solid fine particles leak from the gap in the coupling portion has occurred. This because of the following reason. In the case of liquid, due to its nature, the liquid is less liable to enter the gap in the coupling portion due to surface tension, and a pressure applied to the O-ring is low so that leakage of substances is less liable to occur. However, the solid fine particles easily enter the gap, and a pressure higher than that of liquid is applied to the O-ring, with the result that leakage of substances occurs.

Further, it is conceivable to reduce an elastic force of the O-ring in order to suppress leakage of the substances. However, in this case, the contact resistance between the O-ring and the flow path member increases, and hence there is a fear in that ease of operation at the time of coupling two flow paths to each other or decoupling the two flow paths from each other is reduced.

The present invention has been made in view of the above-mentioned circumstances, and has a first object to provide a seal device capable of reliably preventing leakage of substances from a gap in a coupling portion for two flow paths, and has a second object to provide a seal device capable of easily improving ease of operation at the time of coupling the two flow paths to each other and decoupling the two flow paths from each other.

Solution to Problem

According to the present invention, there is provided a seal device including: a first flow path which allows substances to pass therethrough; a second flow path separably coupled to the first flow path; a sealing member, which has elasticity, and is held in a gap in a coupling portion between the first flow path and the second flow path; and a sealing member deforming part that closes the gap in the coupling portion by deforming the sealing member when the first flow path and the second flow path are to be coupled to each other.

Further, it is preferred that the sealing member deforming part allow the deformed sealing member to restore to an original shape when the first flow path and the second flow path are to be decoupled from each other.

Advantageous Effects of Invention

According to the present invention, it is possible to reliably prevent leakage of substances from the gap in the coupling portion for the two flow paths while improving the ease of operation at the time of coupling the two flow paths to each other and decoupling the two flow paths from each other.

DESCRIPTION OF EMBODIMENTS

A seal device according to the present invention is suitably applied to, for example, a powder jet deposition device (hereinafter referred to as “PJD device”) used for dental treatment. The PJD device is a device used for film forming processing (powder jet deposition method) of injecting solid fine particles onto an object at high speed at normal temperature under normal pressure and causing the solid fine particles to collide with the object to form a film-forming layer in which the solid fine particles are adhered on the object. As the solid fine particles, generally, powdery fine particles having a particle diameter of from about 0.1 μm to about 10 μm are used. There has been an attempt for practical use of the film forming processing with the PJD device in various technical fields.

FIG.1shows an example of a PJD device1. The PM device1includes a hand piece10and a fine particle supply unit11. The hand piece10includes a nozzle18that injects solid fine particles toward a surface of a tooth of a patient. The fine particle supply unit11mixes and disperses solid fine particles with gas such as air or nitrogen gas and supplies the solid fine particles subjected to dispersion treatment to have a predetermined particle diameter to the hand piece10along with jet flow of the gas. In the example illustrated inFIG.1, the hand piece10and the fine particle supply unit11are connected to each other via a pipe such as a hose separably coupled by a connector12.

The seal device according to the present invention can be suitably applied to, for example, a coupling portion for flow paths, which are separably coupled to each other, formed in the hand piece10or the connector12in such a PJD device1. So, the seal device is used as a device which closes a gap in the coupling portion for the coupled flow paths, and improves airtightness of the flow path to stabilize flow (flow velocity or flow rate) of the solid fine particles.

First Embodiment

A first embodiment in which the seal device according to the present invention is applied to a coupling portion15for a flow path16(16A and16B) formed in the hand piece10is described.

In the hand piece10, the solid fine particle flow path16for causing solid fine particles to flow through along with jet flow of gas is formed so as to extend along an axial direction. With this, the solid fine particles supplied from a rear end side of the hand piece10flow through the solid fine particle flow path16to be injected from the nozzle18provided on a distal end side of the hand piece10.

As illustrated inFIG.2, the hand piece10is separable into a front-part casing (first flow path member)13and a rear-part casing (second flow path member)14, and the front-part casing13and the rear-part casing14are removably coupled to each other via the coupling portion15. The front-part casing13and the rear-part casing14have a first flow path16A and a second flow path16B formed therein, respectively. When the front-part casing13and the rear-part casing14are coupled to each other, the first flow path16A and the second flow path16B are coupled to each other to form the solid fine particle flow path16(seeFIG.4). When the front-part casing13and the rear-part casing14are decoupled from each other, the solid fine particle flow path16is separated into the first flow path16A and the second flow path16B (seeFIG.3).

The coupling portion15includes a female coupling portion15A provided on the front-part casing13side, and a male coupling portion15B provided on the rear-part casing14side. The male coupling portion15B is inserted into the female coupling portion15A to couple the front-part casing13and the rear-part casing14to each other. The specific configurations of the female coupling portion15A and the male coupling portion15B are not particularly limited. The coupling portion15may be formed with the front-part casing13as a male side and the rear-part casing14as a female side,

In the illustrated example, the female coupling portion15A includes two recessed portions21and22formed in a stepped shape at a rear portion of the front-part casing13. These recessed portions21and22include a cylindrical first recessed portion21, and a cylindrical second recessed portion22formed behind the first recessed portion21to have a diameter larger than that of the first recessed portion21. The first flow path16A is formed at a center portion of the first recessed portion21.

Meanwhile, the male coupling portion15B includes two protruding portions23and24that are formed in a stepped shape at a front portion of the rear-part casing14, and are inserted into the two recessed portions21and22of the female coupling portion15A. These protruding portions23and24include a first protruding portion23that has a circular outer periphery and is inserted into the first recessed portion21, and a second protruding portion24that is formed behind the first protruding portion23to have a diameter larger than that of the first protruding portion23and is inserted into the second recessed portion22. The second flow path16B to be coupled to the first flow path16A is formed at a center portion of the first protruding portion23.

Further, the coupling portion15between the front-part casing13and the rear-part casing14includes a first sealing mechanism40that seals a space between the second recessed portion22and the second protruding portion24, and a second sealing mechanism50that seals a space between the first recessed portion21and the first protruding portion23in order to prevent leakage of solid fine particles or gas to the outside from the gap in the coupling portion15.

In the illustrated example, the seal device according to the present invention is applied to the second sealing mechanism50.

The first sealing mechanism40includes a peripheral groove41formed in an outer peripheral surface of the second protruding portion24, and a sealing member42held in the peripheral groove41. When the front-part casing13and the rear-part casing14are coupled to each other, the sealing member42comes into elastic contact with an outer peripheral surface24aof the second protruding portion24and an inner peripheral surface22aof the second recessed portion22to close the gap between the outer peripheral surface24aof the second protruding portion24and the inner peripheral surface22aof the second recessed portion22.

As illustrated inFIG.3andFIG.4, the second sealing mechanism50includes a movable member30(sealing member deforming part), and a sealing member52. The movable member30includes a cylindrical main body portion32, and a flange portion33formed integrally with the main body portion32to protrude in an outer peripheral direction from a front end portion of the main body portion32, The main body portion32of the movable member30itself serves as a part of the second11owpath16B, and is held so as to be slidable in a flow path direction by the rear-part casing14in which the second flow path16B is formed. The sealing member52is arranged in a groove portion51formed by the main body portion32and the flange portion33of the movable member30and a front end portion wall23aof the first protruding portion23. The groove portion51is formed to have a changeable groove width between the rear-part casing14and the flange portion30, and when the movable member30slides in the flow path direction, the groove width of the groove portion51is changed.

The movable member30is arranged so as to be able to reciprocate with a small resistance by a rubber-like O-ring37arranged in an annular peripheral groove36formed in an inner peripheral surface of the rear-part casing14that holds the movable member30.

When the front-part casing13and the rear-part casing14are coupled to each other, as illustrated inFIG.5(b), the sealing member52is deformed to close the gap between the outer peripheral surface23bof the first protruding portion23and the inner peripheral surface21aof the first recessed portion21, thereby preventing leakage of the solid fine particles to the outside from the coupling portion between the first flow path16A and the second flow path16B. The specific operation example of such a second sealing mechanism50is described with reference toFIG.5.

At the time of coupling the front-part casing13and the rear-part casing14to each other, when the first protruding portion23of the male coupling portion15B is inserted into the first recessed portion21of the female coupling portion15A, as illustrated inFIG.5(a), the flange portion33of the movable member30is brought into abutment against the front end portion wall21bof the first recessed portion21. A slight gap is formed between the sealing member52and the inner peripheral surface21aof the first recessed portion21until the flange portion33of the movable member30is brought into abutment against the front end portion wall21bof the first recessed portion21, and hence the first protruding portion23can be inserted into the first recessed portion21without any resistance, thereby improving ease of operation.

Further, when the first protruding portion23is further inserted from the state ofFIG.5(a), as illustrated inFIG.5(b), the movable member30is pressed by the front end portion wall21bto be slid rearward as indicated by the arrow inFIG.5(b). Along with this, the flange portion33is moved, and the groove portion51is narrowed to have a width51bso that an external force is applied to the sealing member52. With this, the sealing member52is deformed so as to protrude in the outer peripheral direction while being compressed to reliably close the gap between the outer peripheral surface23bof the first protruding portion23and the inner peripheral surface21aof the first recessed portion21.

Further, when the front-part casing13and the rear-part casing14is to be decoupled from each other, and the rear-part casing14(male coupling portion15B) is to be pulled out from the front-part casing13(female coupling portion15A), as illustrated inFIG.5(c), the flange portion33of the movable member30is separated from the front end portion wall21bof the first recessed portion21, and the flange portion33is pressed by an elastic force of the sealing member52, and the flange portion33is moved forward as indicated by the arrow inFIG.5(c)so that the groove portion51is expanded to have a width51aof the original state, With this, the external force to the sealing member52is eliminated, and the sealing member52is accommodated in the groove portion51under a state of being restored to an original shape due to elastic deformation. Thus, a slight gap is formed between the sealing member52and the inner peripheral surface21aof the first recessed portion21, and the rear-part casing14can be pulled out without any resistance, thereby improving the ease of operation.

Further, the front end portion wall23aof the first protruding portion23has a tapered surface inclined so as to be gradually increased in diameter toward the rear side. With this, a space for allowing the sealing member52to be deformed can be secured, and when the flange portion33applies an external force to the sealing member52, the sealing member52is guided in the outer peripheral direction along the tapered surface so that a contact pressure of the sealing member52against the inner peripheral surface21aof the first recessed portion21can be increased.

Further, when the hand piece10is to be separated, the space for allowing the sealing member52to be easily restored to the original shape can be secured, and movement of the movable member30is facilitated.

In this embodiment, a predetermined gap is secured between the sealing member52and the inner peripheral surface21aof the first recessed portion21, but it is not always required that the gap be secured. Preferably, the outer diameter, the hardness, and the like of the groove portion51or the sealing member52are appropriately set such that, when the hand piece10is to be separated, the sealing member52is brought into contact at a minimum necessary contact pressure, and at the time of coupling, the sealing member52is brought into contact at a contact pressure necessary for preventing leakage of solid fine particles. Further, the sealing member52may be any material or shape as long as the sealing member52is elastically deformable, and a rubber-like O-ring is used as an example.

The second sealing mechanism50configured as described above as the seal device according to this embodiment includes the first flow path16A which allows solid fine particles pass therethrough, the second flow path16B separably coupled to the first flow path16A, the sealing member52held in the gap in the coupling portion15between the first flow path16A and the second flow path16B, and the movable member30that mechanically applies an external force to the sealing member52when the first flow path16A and the second flow path16B are to be coupled to each other to deform the sealing member52and close the gap in the coupling portion15.

Further, the movable member30eliminates the external force mechanically applied to the sealing member52when the first flow path16A and the second flow path16B are to be decoupled from each other to allow the deformed sealing member52to be restored to the original shape.

Thus, in the coupled state, the contact pressure of the sealing member52can be increased, and at the time of coupling operation or decoupling operation, the contact pressure of the sealing member52can be reduced. Accordingly, leakage of substances from the gap in the coupling portion15can be reliably prevented while improving the ease of operation at the time of coupling operation or decoupling operation.

Further, the front end portion wall23aof the first protruding portion23has the tapered surface inclined so as to be gradually increased in diameter toward the rear side. Thus, the space for allowing the sealing member52to be deformed can be secured, and when the flange portion33applies an external force to the sealing member52, the sealing member52is guided in the outer peripheral direction along the tapered surface, thereby being capable of improving the contact pressure of the sealing member52against the inner peripheral surface21aof the first recessed portion21.

Second to Eighth Embodiments

Next, seal devices according to second to eighth embodiments of the present invention are described with reference toFIG.6toFIG.12.

The same reference symbols as those of the above-mentioned embodiment are used for configurations common to the above-mentioned embodiment, and the description of the above-mentioned embodiment may be incorporated herein by reference.

As illustrated inFIG.6, the seal device according to the second embodiment is different from the above-mentioned embodiment in that two sealing members52formed of an O-ring are arranged in parallel in one groove portion51. According to such a seal device, further improvement in sealability can be expected.

As illustrated inFIG.7, the seal device according to the third embodiment is different from the above-mentioned embodiment in that an O-ring having an elliptical sectional shape is applied to the sealing member52. Even with such a seal device, the same effects as those of the above-mentioned embodiment are obtained.

The seal device according to the fourth embodiment is different from the above-mentioned embodiment in that the sealing member52has a plate-like sectional shape as illustrated inFIG.8. Specifically, the sealing member52formed in a plate shape is arranged while being curved so as to protrude with respect to the groove portion51. Further, in the case of this embodiment, the sealing member52may fall off from the groove portion51, Thus, for example, it is preferred that an engagement member for causing a part of the sealing member52to be engaged with the rear-pad casing14(first protruding portion23) be provided to the sealing member52to fix the sealing member52to the rear-part casing14(first protruding portion23). Even with such a seal device, the same effects as those of the above-mentioned embodiment are obtained.

The seal device according to the fifth embodiment is different from the above-mentioned embodiment in that the first flow path16A side is formed as a male side and the second flow path16B side is formed as a female side, and the movable member30is mounted on the first flow path16A side as illustrated inFIG.9. Even with such a seal device, the same effects as those of the above-mentioned embodiment are obtained.

The seal device according to the sixth embodiment is different from the above-mentioned embodiment in that a tapered surface is formed not on the front end portion wall23aof the first protruding portion23but on the flange portion33side of the groove portion51as illustrated inFIG.10. Even with such a seal device, the same effects as those of the above-mentioned embodiment are obtained.

The seal device according to the seventh embodiment is different from the above-mentioned embodiment in that the first flow path16A side is formed as a male side and the second flow path16B side is formed as a female side, the movable member30is mounted on the first flow path16A side, and the a tapered surface is formed on the flange portion33side of the groove portion51as illustrated inFIG.11, Even with such a seal device, the same effects as those of the above-mentioned embodiment are obtained.

The seal device according to the eighth embodiment is different from the above-mentioned embodiment in that the movable member30is mounted to the first flow path16A side as a female side, and a tapered surface is formed on the flange portion33side of the groove portion51as illustrated inFIG.12. According to such a seal device, an adhesion strength between the flange portion33and a front end surface of the rear-part casing14in contact with the flange portion33can be easily improved, thereby being capable of preventing leakage of substances from the coupling portion similarly to the above-mentioned embodiment.

The preferred embodiment of the seal device according to the present invention is described above, but the seal device according to the present invention is not limited to the embodiments described above. It goes without saying that various modifications can be made within the scope of the present invention.

For example, in the above-mentioned embodiment, an example in which the present invention is applied to the coupling portion for the flow paths, which are separably coupled to each other, formed in the hand piece10of the PJD device1in the dental treatment system has been described, but the present invention is not limited thereto. The present invention may be applied to the coupling portion for the flow paths which are separably coupled to each other in various devices, thereby being capable of preventing leakage of substances from the gap in the coupled flow path.

REFERENCE SIGNS LIST