JPS6122580Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a dental handpiece with a built-in rotation speed detector.

Cutting handpieces used in dental treatment rotate a tool attached to the head at high speed, but the rotational speed usually drops considerably under load. Knowing the rotation speed under load is desirable in order to perform appropriate treatment, is also effective in clinical experiments, and is also necessary when performing control to keep the rotation speed constant. becomes. For this reason, in micromotor-driven handpieces, attempts have been made to detect the rotation speed using the voltage and current of the motor and use it to display and control the rotation speed. This means that the rotation speed can be determined indirectly, and there is a large amount of error.In addition, with air-driven types, the rotation speed cannot be determined indirectly like with electric types, and in most cases, the rotation speed cannot be determined indirectly when the load is applied. It is used without knowing the actual rotation speed.

In order to solve this problem, in an air-driven handpiece, a vibration detection device is installed in the exhaust passage in the joint device to detect the rotation speed (Japanese Patent Laid-Open No. 54
-27294)), and one in which the rotational speed is detected magnetically by magnetizing the circumferential surface of the rotating shaft of an air turbine and arranging a magnetic resistance element at a position facing the magnetized surface (see Japanese Patent Laid-Open No. 54-51304). However, the former has a complicated vibration detection device structure and is unreliable as it indirectly determines the rotational speed of the air turbine through vibration. Bearings and surrounding parts may need to be made of non-magnetic materials, or the ultra-rigid rotor that holds the cutting tool must be magnetized, or magnets must be used to keep the rotor highly circular to prevent rotational runout. In addition to being constrained in design because of the need to attach
The problem is that the structure tends to become complicated.

The present invention was made with the aim of solving these problems and providing a dental handpiece that can accurately determine the rotational speed of the rotor. an intermittent reflective surface provided on the lower outer circumferential surface of a rotor shaft for mounting tools, the upper and lower portions of which are rotatably supported by air bearings or ball bearings; and a glass fiber provided inside the handpiece. a light emitting unit that directs a light beam sent from a light source provided inside or outside the handpiece to the intermittent reflective surface; The handpiece is characterized by being equipped with a non-contact rotation speed detector consisting of a light receiving section provided inside or outside of the handpiece that sends the information to the control section.

Hereinafter, the present invention will be explained with reference to the illustrated embodiments. FIG. 1 shows an embodiment of a conventionally well-known air-driven, air-bearing type handpiece, where 1 is a handpiece, 2 is a head, 3 is a front guide press-fitted into a rotor shaft 7', and 4 is a rotor shaft 7'. ' is an impeller, 5 is a nozzle that supplies air to the impeller 4 and the bearing, and 6 is a water nozzle. Chamfers 8 are formed on both sides of the rotor shaft tip 7 at the tip of the rotor shaft 7' for attachment and detachment of tools.
Two glass fibers 9 and 10 for optical transmission are arranged so that the terminal is located close to the terminal. These glass fibers 9 and 10 are used for the head 2 made of brass or the like.
stainless steel protective tube 11 embedded in
It is housed in 12. The rotor shaft tip 7 is notched at two places on the circumference by chamfers 8, making it discontinuous, and the reflectance of the circumferential surface other than the chamfer 8 is made higher than that of the chamfer 8 to cover the entire circumference, that is, as shown in the figure. An intermittent reflective surface 13 is formed on the outer peripheral surface of the lower part of the rotor shaft 7' as shown in FIG. On the other hand, the glass fibers 9 and 10 are led out from the handpiece 1, as shown in FIG. The glass fibers 10 are each connected to a light receiving element 15 such as a phototransistor, and the terminal of the glass fiber 9 is a light emitting section 16, and the terminal of the glass fiber 10 is a light receiving section 17. That is, in this embodiment, the intermittent reflective surface 1 provided on the circumference of the rotor shaft tip 7
3, the light emitting part 16 and the light receiving part 17 of the glass fibers 9 and 10 constitute a non-contact type rotation speed detector 18. A pulsed optical signal is sent to the light receiving section 1.
7 and is converted into an electrical signal by the light receiving element 15. In addition, as shown in FIG. 2b, the light source 14
Alternatively, one or both of the light receiving elements 15 may be provided within the hand piece 1. The electrical signal obtained in this way accurately corresponds to the rotational speed of the rotor shaft 7', so this signal is sent to the control unit and electrically processed to display and record the rotational speed. It can be used for control purposes, etc., and the accuracy of rotation speed detection is greatly improved compared to the case where rotation speed is detected indirectly through voltage, current, or vibration, making it possible to use it more appropriately.

Fig. 3 shows an embodiment of a conventionally well-known air-driven, ball-bearing type handpiece.Since the basic configuration is the same as that shown in Fig. 1, the same parts are denoted by the same symbols, and details are shown. Further explanations will be omitted.

In the above embodiment, the intermittent reflective surface 13 is formed using the two chamfers 8 of the rotor shaft tip 7, but as shown in FIG. It is also possible to form portions 19 with different ratios, and the number thereof can be arbitrarily selected from one to a plurality.

Further, the intermittent reflective surface 13 can also be provided at the tip of the impeller 4. That is, as shown in Fig. 5, the cylindrical surface at the tip of the blade is made into an intermittent reflective surface 13 by utilizing the unevenness of the impeller, and in this case, the number of blades changes per rotation of the rotor shaft 7'. A pulse-like optical signal equal to . Note that some well-known handpieces are equipped with a lighting device in the head and the illumination light is transmitted through a glass fiber, and the glass fiber used for lighting is quite thick in order to increase the amount of transmission. However, since the glass fibers 9 and 10 in each of the above-described embodiments only need to be capable of transmitting signals, they may be much thinner than those for illumination. Further, it is also possible to use a glass fiber 9 for illumination instead of separately providing the glass fiber 9 for transmitting light from the light source 14.

Although not shown, regarding the connection between the tube and the handpiece, as shown in FIG. If the mirror-finished fibers, which are constructed by interposing layers and are rotated coaxially at the joint between the tube and the handpiece, can be freely rotated at the joint with little energy loss. In addition, in an embodiment in which the glass fiber 10 for receiving and transmitting light has one type of glass fiber as shown in FIG. By rotating it at the central axis position, a free-rotation connection is possible as described above.

As described above, the present invention provides a rotation speed detector consisting of an intermittent reflective surface provided on the rotor shaft and a corresponding light emitting part and light receiving part in the head, and transmits and receives light beams through a glass fiber. The rotor's rotational speed can be directly detected, unlike those that indirectly detect the rotational speed using voltage, current, vibration, etc., so it is possible to accurately detect the rotational speed. In addition, there are no restrictions on the material or structure of bearings, etc., as is the case with detection systems that use magnetism.Furthermore, since light is transmitted and received using glass fibers, the light emitting part and light receiving part are placed close to the rotor. easy to place;
This has the advantage of simplifying the structure of the handpiece.

In addition, the present invention has a wide range of applications, and can be applied to various types of handpieces, regardless of the drive method such as electric drive type or air drive type, and including straight types in which the output shaft is installed in the longitudinal direction of the handpiece. This has the advantage of being able to know the exact number of revolutions under load, allowing effective implementation of dental training, clinical experiments, treatments, and various types of control.

[Brief explanation of the drawing]

The drawings are all embodiments of the present invention; Figures 1a and b are side sectional views and bottom views of the main parts of the air bearing type; Figures 2a and b are side views showing the connection status;
Figures 3a and 3b are side sectional views and bottom views of the main parts of the ball bearing bearing type, Figures 4a and 4b are side views and perspective views of the main parts of another embodiment, and Figure 5 is still another embodiment. FIG. 2 is a perspective view of main parts of the embodiment. Explanation of symbols, 1...Hand piece, 2...Head, 7'...Rotor shaft, 9, 10...Glass fiber, 13...Intermittent reflective surface, 14...Light source, 16
... Light emitting section, 17 ... Light receiving section, 18 ... Rotation speed detector.

Claims (1)

[Scope of Claim for Utility Model Registration] The upper and lower parts of an impeller driven by air inside the head of a dental handpiece are rotatably supported by air bearings or ball bearings on the lower outer peripheral surface of a rotor shaft for mounting tools. an intermittent reflective surface provided therein; a light emitting unit that illuminates the intermittent reflective surface with a light beam sent from a light source provided inside or outside the handpiece via a glass fiber provided inside the handpiece; and the intermittent reflective surface A non-contact rotation speed detector is provided, comprising a light receiving section installed inside or outside the handpiece, which receives reflected light from the handpiece and sends it to the control section via a glass fiber installed inside the handpiece. A dental handpiece characterized by: