JPH0453774Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a handpiece used for cutting teeth, etc. in dentistry.

2. Prior Art FIG. 2 is a diagram for explaining an example of a conventional handpiece. Reference numeral 1 denotes a main shaft rotatably supported on a grip case 3 by two bearings 2; There is a chuck 5 inside the tip to stop the cutting tool 4.
A chuck fastener 6 is rotatably screwed onto the outside of the tip of the main shaft 1 and which slides into contact with the conical portion of the chuck 5. Furthermore, a connecting hole 7 is provided at the rear end of the main shaft 1. It is provided. Reference numeral 8 denotes a conical case that is removably screwed onto the tip of the gripping case 3. When attaching or removing the cutting tool 4 to or from the chuck 5, the conical case 8 is removed from the gripping case 3, and the chuck tightening tool 6 is removed. Rotate to tighten and release the chuck 5. Reference numeral 9 denotes a rotating shaft on which a rotor 11a of a motor 11 is rotatably supported by two bearings 2 on a motor case 10. The rotating shaft 9 has a protrusion 12 at its tip in a radial direction. Protruding coupler 1
3 is installed. Reference numeral 14 denotes a connecting cylinder with a slip ring 15 surrounding the outer periphery.
is fixed to the tip of the motor case 10 by a screw 16.

The above-mentioned handpiece is assembled by attaching the gripping case 3 to the motor case 10 by inserting the connecting cylinder 14 into the rear part of the gripping case 3 and compressing the slip ring 15 against the inner circumferential wall surface of the gripping case 3. hand,
The protrusion 12 is inserted into the connection hole 7 to connect the main shaft 1 and the rotating shaft 9.
was connected. However, since the center line of the main shaft 1 and the center line of the rotating shaft 9 do not coincide with each other, there is a drawback that noise and vibration are generated and the rotating parts are abnormally worn.
4 bearings 2 and main shaft 1 for supporting each
Parts are required to connect the rotating shaft 9, the gripping case 3, and the motor case 10, respectively.
This has the disadvantage that the number of parts and manufacturing man-hours increase, making the motor handpiece complex and expensive.

FIG. 3 is a diagram for explaining an example of a handpiece that solves the above-mentioned drawbacks.
Parts which function similarly to the handpiece shown in the figures are provided with the same reference numerals as in FIG. 2. In this example, in order to solve the above-mentioned drawbacks, the shaft of the chuck and the shaft attached to the rotor of the motor are integrally constructed. A shaft is rotatably supported by two bearings 2 in a case 18 to which a case 8 is screwed, and a chuck 5 is screwed inside the tip of this shaft 17.
A chuck fastener 6 is rotatably screwed onto the outside of the tip of the shaft 17, and a rotor 11a of the motor 11 is attached to the rear of the shaft 17. Therefore, since the shaft on which the chuck 5 and the chuck fastener 6 are mounted and the shaft on which the rotor 11a of the motor 11 is mounted are integrally constructed, it is possible to eliminate misalignment of the center lines of the two shafts.

However, according to the conventional handpiece as described above, when the handpiece is dropped on the floor etc., even though there is no functional difference between before and after the handpiece is dropped, there is a noise when using it. I have changed,
The drawback was that it gave the practitioner a sense of anxiety.

Purpose The present invention was made in view of the above-mentioned circumstances, and was made with the purpose of providing a handpiece whose rotational sound does not change before and after being dropped.

Configuration FIG. 1 is a cross-sectional configuration diagram for explaining one embodiment of the handpiece according to the present invention. In the figure, 21 is a test pin, 22 is a chuck, 23 is a spindle, 24 is a motor rotation shaft, and 25 is a bearing, 2
6 is a preload spring, 27 is a chuck pin, 28
29 is a flat spring, 30 is a front bearing, and in this invention, the motor rotation shaft 2
4 is supported at one end by a rear bearing 25 via a spindle 23 internally connecting the motor rotation shaft 24, and the chuck 22 is supported by a front bearing 30 via the spindle internally connecting the chuck 22. supported by
As a result, the motor rotating shaft 24 is connected to the chuck 22 via the spindle 23 by a chuck pin 27 on the rear side of the chuck.
This chuck pin 27 is pushed by a flat spring 29 through a chuck pusher 28 in the direction of arrow A, while the preload spring 26 resists the pressing force of the flat spring 29 and pushes the rear bearing 25 in the direction of arrow A. The spindle 23 is pressed in the direction of arrow B via the bearing 25. That is, the spindle 23 is rotatably supported by two bearings 25 and 30,
These bearings 25, 30 are axially acted upon by spring members 26, 29 which axially oppose and press the spindle 23 to hold it in a predetermined position. In the illustrated example, the preload spring 26 is
The flat spring 29 is interposed between the bearing 30 and the chuck presser to push the spindle 23 in the direction of arrow A, and presses the spindle 23 in the direction of arrow A. Thus, although the spindle 23 is axially opposed and pressed against each other by the spring members 26 and 29, this is merely an example, and the invention is not limited to this illustrated example. Thus, according to the present invention, the spindle 23 is movable in the direction of the arrow A or B, and is held in a predetermined position by the springs 26 and 29, so that even if it receives a temporary impact, it is not affected. The engine absorbs the impact and then returns to its original state, so there is no change in the rotational sound before and after receiving the impact.

Effects As is clear from the above explanation, according to the present invention, it is possible to provide a handpiece whose rotating sound does not change even if it is dropped on the floor or the like.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional configuration diagram for explaining one embodiment of the handpiece according to the present invention, and FIGS.
The figures are cross-sectional configuration diagrams for explaining examples of conventional handpieces. 21...Test pin, 22...Chick, 23
...Spindle, 24...Motor rotating shaft, 25...
...Bearing, 26...Preload spring, 27...
...Chuck pin, 28...Chuck pusher, 29
...Flat spring, 30...Front bearing.

Claims (1)

[Scope of utility model registration request] A handpiece having a chuck for fixing a cutting tool and a motor for driving the chuck,
The shaft of the chuck and the rotating shaft of the motor are connected via a spindle that is movable in the axial direction, and the spindle is supported by two bearings,
A hand piece characterized in that a spring member is applied to both bearings in the axial direction to press the spindle axially opposite to each other.