JP2954919B2 - Dental straight 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 dental straight handpiece, and more particularly, to cutting powder or the like cut by a cutting tool of the handpiece reaches a bearing provided in the handpiece. It is intended to prolong the service life of the bearing by making it harder.

[0002]

2. Description of the Related Art FIG. 2A is a structural view of a main portion for explaining an example of a conventional straight dental handpiece.
2 (B) is an enlarged detailed view of a part II in FIG. 2 (A). In the drawing, 1 is a chuck shaft having a plurality of slits 1a in the axial direction, 2 is a cutting bar held by the chuck 1 and 3 is The tip of the chuck shaft provided with the slit 1a is pressed against the cutting bar 2 or separated from the cutting bar 2 to fix the cutting bar 2 to the chuck shaft, or
The rotating shaft 3 is rotated by a motor (not shown) so that the chuck shaft 1 can be inserted into and removed from the chuck shaft 1. When the cutting bar 2 is held between the rotating shaft 3 and the chuck 4, Pushing in the direction of arrow A, the cutting bar 2 is firmly held by the rotating shaft 3 via the chuck shaft 1 in the Q section, so that the cutting bar 2 rotates integrally with the rotating shaft 3.

FIG. 2A shows a state in which the cutting bar 2 is chucked by the chuck shaft 1. In this chuck state, when the lever 5 is turned around the axis P, the cam 6 is turned. When the chuck shaft 1 is further rotated, the chuck shaft 1 is moved in the direction B against the spring 4,
Thereby, the engagement between the rotary shaft 3 and the chuck shaft 1 in the Q portion is released, and the cutting bar 2 can be freely inserted into and removed from the chuck shaft 1.

As described above, in the conventional dental straight handpiece, the lever 5 is rotated against the spring 4 and the cutting bar 2 is inserted into the chuck shaft 1 in this state. Is returned to the original predetermined position, so that the cutting bar 2 is attached to the handpiece.

Further, in FIG. 2A, bearings 9 and 10 rotatably support the rotating shaft 3 with respect to the handpiece body 8, and the bearing 10 provided on the tip side of the handpiece is As shown in FIG. 2 (B), which shows a portion II in FIG. 2 (A) in an enlarged manner, the inner race 10a comprises an inner race 10a which rotates integrally with the rotating shaft 3 and an outer race 10b which is fixed to the handpiece body 8. The bearing 10 has an inner race retainer 11, outer race retainers 12, 13 and the like at the tip end thereof, and furthermore, the inner race retainer 11 and the inner race 10a rotate integrally with the rotating shaft 3. Dust-proof rotating disk 14, outer race 10b and outer race holder 12
Has a fixed dustproof disc 16 or the like which is disposed between the arranged fixation dustproof disc 15 and the outer race 10b and outer race retainer 13 between, these cutting bars 2
In this way, it is possible to prevent the cutting powder or the like that has been cut by the above from reaching the bearing 10. Note that, in the enlarged detailed view of FIG. 2B, arrows indicate a path through which dust reaches the bearing 10.

As described above, in a dental straight handpiece, for example, during machining of a denture or the like, the dust cut by a cutting tool is prevented from reaching the bearing 10 or is delayed, so that the bearing 10 is damaged. As described above, the conventional dust-proof wall has a long passage in the radial direction so that dust mainly moves in the radial direction. And the effective path length cannot be made sufficiently long (the centrifugal force makes the passage C in the outer peripheral direction almost useless, and the previous central passage D has the outer peripheral passage in the outer peripheral direction of the next passage C). The centrifugal force exerts a suction force, so it does not work very effectively), but it was not always satisfactory.

[0007] In view of the above situation, the applicant of the present invention first described the path through which dust reaches the bearing, mainly as follows.
A straight handpiece has been proposed which has an axial direction, which increases the effective path for dust to reach the bearing, prevents damage to the bearing, or prolongs the life of the bearing (Japanese Patent Application No. 9-96164). .

FIG. 3A is a view for explaining an example of a dental straight handpiece previously proposed by the present applicant. In FIG. 3A, parts having the same functions as those of the prior art shown in FIG. Are denoted by the same reference numerals as in FIG. 2, and detailed description thereof will be omitted. FIG. 3B is an enlarged view of a portion III in FIG. 3A. In FIG. 3, reference numeral 21 denotes an inner race retainer integrated with the rotating shaft 3, and the inner race retainer 21 allows the inner race 10 a of the bearing 10 to rotate. It prevents movement in the direction. Reference numeral 22 denotes an outer race retainer integrated with the handpiece body 8.
0b is prevented from moving in the axial direction. In the case of the illustrated example, the inner race presser 21 has a concave 21 in the axial direction.
a, a protrusion 21b, and the outer race retainer 22 has a concave 22a and a convex 22b that nest with the concave and convex of the inner race retainer 21, and the dust cut by the cutting bar is Bearing 1 through the path indicated by the arrow
Reach 0. In this way, the dust generated by the cutting bar mainly reaches the bearing by following the path provided in the axial direction of the handpiece.Therefore, the path on which the centrifugal force acts is small, and therefore, until the bearing is reached. The effective path is long, and the bearing can be maintained effectively.

In FIG. 3, reference numeral 23 is further forward of the outer race retainer 22, integrated with the rotating shaft 3, and
The recess 22 provided on the tip side of the outer race presser 22
a ', a dustproof member having a concave 23a and a convex 23b which engage with the convex 22b'. In this way, by expanding the dust path in the axial direction of the handpiece, the bearing is more effectively prevented from dust. In order to extend the life of the bearing.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is to further improve the straight handpiece as described above so as to prevent dust from further reaching the bearing portion.

According to the present invention, in order to achieve the above object, dust is caused to flow outward in the axial direction by utilizing centrifugal force generated by rotation of a rotating shaft, thereby preventing dust from flowing into a bearing portion. Things.

[0012]

According to the first aspect of the present invention, there is provided a straight type handpiece main body, a rotary shaft having a hollow tip end rotatably disposed in the main body via a bearing, and A chuck shaft disposed in the shaft, and a bearing provided on the distal end side of the handpiece, the distal end side of the bearing being fixed to the rotating shaft to move the inner race of the bearing in the axial direction. has an inner race retainer member for preventing the outer race holding member for preventing axial movement of the outer race of the bearing is secured to the handpiece body, a dust-proof member attached on the cutting edge of said rotary shaft characterized in that the tip-side surface of-proof dust member is formed on the inclined surface as a thin toward the axially inner side, it has been, rotated supporting the rotary shaft of the dental handpiece The bearing part of those dust was prevented penetrate.

According to a second aspect of the present invention, in the first aspect of the present invention, the inner race pressing member and the outer race pressing member have concentric irregularities in a nested manner in the axial direction. Therefore, compared with the first aspect of the present invention, dust is prevented from entering the bearing portion for rotatingly supporting the rotating shaft of the dental handpiece.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1A is a sectional view of an essential part for explaining an embodiment of a straight handpiece according to the present invention, and FIG. 1B is an enlarged detailed view of a part I in FIG. 1A. In the figure, parts having the same functions as those of the prior art shown in FIG. 3 are denoted by the same reference numerals as in FIG. Thus, in the present invention, the front end surface of the member (the dustproof member in FIG. 1) 23 that rotates integrally with the rotating shaft 3 has an inclined surface whose diameter decreases toward the inside in the axial direction. 23A, whereby the centrifugal force in the direction of arrow A acting on the inclined surface 23A acts when the rotating shaft 3 rotates,
That is, a centrifugal force acting outward in the axial direction of the rotating shaft 3 acts,
Dust is released to the outside through an escape hole R provided at the tip of the handpiece body 8 and hardly enters the handpiece body. Therefore, the probability that the bearing in the handpiece is damaged by dust or the like is small, and the handpiece can be used for a long period (long life).

FIG. 1 shows a nested dustproof member 23.
The example in which the inclined surface 23A is provided on the front surface of the
The present invention is not necessarily limited to the nesting type dustproof member, and the same effect can be obtained by applying the above-described inclined surface to the front surface of the most advanced member of the member that is integrally rotated with the rotating shaft. It is easy to find out what can be done.

[0016]

According to the first aspect of the present invention, there is provided a straight type handpiece main body, a rotary shaft having a hollow end portion rotatably disposed within the main body via a bearing, and a rotary shaft disposed within the rotary shaft. A bearing provided on the distal end side of the handpiece, the inner race being fixed to the rotating shaft on the distal end side of the bearing to prevent axial movement of the inner race of the bearing. includes a pressing member, and the outer race retaining member to which the is secured to the handpiece body to prevent axial movement of the outer race of the bearing, and a dustproof member mounted on the cutting edge of said rotary shaft,-proof dust Dust enters the bearing that rotates and supports the rotating shaft of the dental handpiece because the surface on the tip side of the member is formed as an inclined surface that has a smaller diameter toward the inside in the axial direction. Hard to.

According to a second aspect of the present invention, in the first aspect of the present invention, the inner race pressing member and the outer race pressing member have concentric unevenness in a nested manner in the axial direction. In addition, dust is less likely to enter the bearing portion that rotatably supports the rotating shaft of the dental handpiece as compared with the invention of the third aspect.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part for explaining an embodiment of a straight handpiece according to the present invention.

FIG. 2 is a sectional view of an essential part for explaining an example of a conventional straight handpiece.

FIG. 3 is a cross-sectional view of a main part for describing an example of a straight handpiece proposed by the present applicant earlier.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Chuck axis | shaft, 2 ... Cutting bar , 3 ... Rotation axis, 4 ... Spring, 5 ... Lever, 6 ... Cam, 7 ... Pressing fitting, 8 ... Handpiece body, 9,10 ... Bearing, 21,22 ...
Bearing retainer, 23: dustproof member, 23A: inclined surface.

Claims (2)

(57) [Claims] 1. A straight type handpiece main body, a rotary shaft having a hollow tip end rotatably disposed in the main body via a bearing, and a chuck shaft disposed in the rotary shaft. An inner race holding member fixed to a rotating shaft at a tip end side of the bearing provided on the tip end side of the hand piece to prevent axial movement of an inner race of the bearing, and the hand piece; An outer race pressing member fixed to the main body to prevent the outer race of the bearing from moving in the axial direction;
And a dust-proof member attached to the tip of the rotating shaft.
A straight handpiece for dental use, wherein a surface on the tip end side of the dustproof member is formed on an inclined surface having a smaller diameter toward an inner side in the axial direction. 2. The dental straight handpiece according to claim 1, wherein the inner race pressing member and the outer race pressing member have concentric irregularities in a nested manner in the axial direction.