JPH0412779Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to the improvement of micromotors used in dentistry, etc. More specifically, the invention aims to improve the accuracy of rotation speed detection by adopting a rotary encoder. It is something to do.

(Prior art) The rotational speed of micromotors used in dental handpieces and the like has been detected using the back electromotive force of brushed motors and the rotational position signal of the rotor magnet for brushless motors. .

(Problem that the invention aims to solve) However, these detection methods cannot obtain accurate rotation speed signals (for example, a lot of ribble occurs).
There is also the problem that the response speed is slow, so the variable range of rotation speed is 10 to 30 times (for example, 4000 to
40,000RPM variable, etc.) was the limit, and it was impossible to expect a wider variable range than that. Therefore, dental micromotors based on such detection methods are insufficient for performing various treatment operations.
If other detection means were to be used instead, the apparatus would become too large and would be unsuitable for dental use. Therefore, the present applicant filed a complaint in 1985-2885
(filed on January 11, 2015), the company provided a micromotor with a built-in rotary encoder. This micromotor has a built-in rotary encoder consisting of a light-emitting element and a light-receiving element, which are arranged opposite to each other on the joining surface of the main body and the connector, and a rotating slit plate and a fixed slit plate interposed between these two elements. The aim is to dramatically improve the practicality of micromotors by detecting the rotational speed of the rotary encoder. However, in such a micromotor, the light-emitting element and the light-receiving element are individually fixed to the main body side or the connector side, so when the screw that connects and fixes the main body and the connector is loosened, the connector moves relative to the main body, and this It has been pointed out that the optical axis between the light-emitting element and the light-receiving element changes with each movement, which causes the output signal from the light-receiving element to fluctuate, making it impossible to detect the rotational speed with high precision. .

This invention was created in view of the above, and by providing a rotary encoder on the main body side, it does not impair the original functionality and operability.
The purpose is to improve the accuracy of rotational speed detection and widen its variable range, thereby enabling its various applications.

(Means for Solving the Problems) The configuration of the present invention will be explained based on embodiment diagrams. FIG. 1 is a partially cutaway vertical sectional view showing a representative example of the micromotor of the present invention, FIG. 2 is a partially cutaway exploded perspective view of the same embodiment, and FIG. 3 is a view similar to FIG. 1 of another embodiment.
Figures 4A and 4B are schematic diagrams of the rotary encoder section. That is, the present invention provides a micromotor comprising a main body 1 containing a rotor 11, and a connector portion 2 detachably connected to the main body 1 from the axial direction of the rotor 11 in order to supply power for driving the rotor 11, etc. A shaft 111 of the rotor 11 extends to the joint surface with the connector portion 2 of the main body 1, and a disk that rotates concentrically with the shaft 111 is provided at this extended end of the shaft 111. A shaped rotating slit plate 31 is fixed, and the main body 1 is provided with an element holder 30 for holding a light emitting element 33 and a light receiving element 34 with their common optical axes parallel to the axis of the rotor 11. , the joint surface of the main body 1 or the holder 30
The rotating slit plate 32 is fixedly interposed between the light emitting element 33 and the light receiving element 34 together with the rotating slit plate 31, and the rotating slit plate 31,
The rotary encoder 3 is constituted by the fixed slit plate 32, the light emitting element 33, and the light receiving element 34. The connecting terminals 4 are embedded in the joints of the main body 1 and the connector part 2, parallel to the axis of the shaft 111 and distal to the rotary encoder 3. It is a micro motor with a built-in rotary encoder.

The figure shows an example of application to a dental handpiece, in which a main body 1 is covered with a case 10, and an adapter (not shown) such as a cutting tool is connected to the operating side of the main body 1 so as to be freely attachable. The case 10 is equipped with a rotor 11 surrounded by a motor coil 112 and an insulating holding member 12, and the shaft 111 of the rotor 11 has a bearing 13 fitted in the holding member 12 and a bearing on the operating side. (not shown), and extends through the holding member 12 to the joint surface with the connector portion 2. The shaft 111 is equipped with a non-magnetic spacer 14, a magnet 15, and a non-magnetic slit plate holder 311 supporting the rotating slit plate 31.
It is integrated with the shaft 111 by a fixing screw 16 screwed into the extending end. In addition, the holding member 12
is equipped with an element holder 30 that holds a light emitting element 33 and a light receiving element 34 facing each other at both ends, and the optical axis l between both elements 33 and 34 is aligned with the axis L of the rotor 11.
oriented parallel to. And these two elements 3
Between 3 and 34, the rotating slit plate 31 and the fixed slit plate 32 are parallel to each other and the rotor 11
A rotary encoder 3 is constructed by interposing the rotary encoder 3 in a state perpendicular to the axis L and the optical axis L (see FIG. 4). Furthermore, on the outside of this rotary encoder, that is, on the distal side with respect to the axis of the shaft 111, there are a total of 10 connector pins 41 connected to the shaft 1.
11, and its tip protrudes toward the connector portion 2 side. Moreover, the holding member 1
2, two magnetic sensors 151 (one of which is not shown in the figure) are fixedly installed at a portion corresponding to the magnet 15 at an angle of 90 degrees to each other. The coil 112, the light emitting element 33, and the light receiving element 34 are electrically connected to connector pins 41, respectively, within the holding member 12.

On the other hand, the connector part 2 is covered with a case 20, and an insulating holding member 21 is provided inside the case 20.
The holding member 21 is embedded with a receiving portion, that is, a spring socket 42 at a portion corresponding to the connector pin 41, and when the main body 1 and the connector portion 2 are connected, the electrical connection terminal 4 is installed. configured. The spring socket 42... has ten electric wires 2 introduced from outside the system and tied tightly to the holding member 21.
2... is connected to... Main body 1 and connector part 2
The connection is made by elastic fitting between the connector pin 41... and the spring socket 42... and the cases 10, 20.
This is done by screwing between both cases 10 and 2.
0 screwing is done through the male screw ring 5. In Fig. 2, this male thread ring 5 is shown tied to the connector part 2 side, but it is only shown like this for convenience; it originally exists independently of the main body 1 and the connector part 2, and when the two are connected, the male thread ring 5 is attached to the connector part 2 side. After screwing the screw ring 5 into the case 10 of the main body 1, the connector part 2
It is obvious that the case 20 should be screwed onto this.

The magnet 15 and the magnet sensor 151 have the function of detecting the rotational speed of the rotor 11, and overlap the function of the rotary encoder 3, which will be described later, but they can also be used together here. I purposely illustrated this to make it clear.

(Function) The rotary encoder 3 is connected to the rotor 1
As the rotating slit plate 31 rotates with the rotation of 1, the many slits 312 radially spaced apart from each other on the rotating slit plate 31 and the slits 321 formed on the fixed slit plate 32 intermittently overlap, and light is emitted. Light from the element 33 is intermittently irradiated onto the light receiving element 34 through this overlapping portion, and the light receiving element 34
The encoder 3 converts the signal into an electrical signal and detects the rotation speed, and the detection by the encoder 3 has an extremely fast response speed and accuracy, and therefore the rotation speed variable range of the rotor 11 is approximately
It is expanded up to about 200 times (for example, 200 to 40000 RPM). If a micromotor with an expanded rotation speed variable range is applied as a handpiece for dental treatment, a variety of treatments can be performed depending on the condition of the affected area.
This is extremely convenient because it is made possible by a single micromotor. Moreover, the encoder 3 is arranged compactly inside the connection terminal 4...
Compared to conventional micromotors of this type, it does not become longer in the longitudinal direction and does not increase in diameter in the diametrical direction, so the operability and functionality of the handpiece are not impaired in any way. . Furthermore, since the rotary encoder 3 is provided in the main body 1 via the element holder 30,
Even if the connection between the main body 1 and the connector part 2 becomes loose and the other part shakes a little, the common optical axis l of both elements 33 and 34 will not be affected in any way, thus ensuring highly accurate rotation speed detection. It is guaranteed.

(Example) Examples will be described below.

(Example 1) In FIGS. 1 and 2, a fixed slit plate 32 is fixed to the holding member 12 of the main body 1, and the light receiving element 34 is placed close behind it (on the tip side of the main body 1). is located. And element holder 30
protrudes toward the connector portion 2, and its tip end is accommodated in a cavity 211 formed in the holding member 21 of the connector portion 2 when the main body 1 and the connector portion 2 are connected. In addition, a light emitting element 33 facing the light receiving element 34 is fixed at the tip of the element holder 30, and an optical axis l common to both elements 33 and 34 is held parallel to the axis L of the rotor 11. A fixed slit plate 32 and a rotating slit plate 31 are interposed between the two elements 33 and 34 in a state perpendicular to the optical axis l. Since the operation of the micromotor incorporating the rotary encoder 3 having such a configuration does not go beyond the above explanation, the explanation thereof will be omitted here.

(Example 2) What is shown in FIG. 3 is a light emitting element 33 and a light receiving element 3.
The front and back positions of the light receiving element 4 are reversed from those in the first embodiment, and the fixed slit plate 32 is fixedly mounted on the element holder 30 so as to be brought close to the light receiving element 34. Functionally, this embodiment is not different from the first embodiment described above, so its explanation will be omitted here as well.

Although an example of application to a handpiece for dental treatment has been shown above, it is obvious that this micromotor, which has a wide variable range of rotational speed, will bring extremely large benefits even when applied to other precision instruments. also,
It goes without saying that the connection method between the main body 1 and the connector part 2 and the form of other members are not limited to the illustrated example, and other forms are possible. It is also optional to provide channels for the feed medium. Furthermore, it is also possible to reverse the positions of the light emitting element 33 and the light receiving element 34 in FIGS. 1 and 3, in which case the light receiving element 34
It is advantageous to place the rotating slit plate 31 as close as possible to the slit plate 31 in order to prevent exposure to light. Furthermore, although the fixed slit plate 32 is fan-shaped in the illustrated example, it goes without saying that it may also be disk-shaped.

(Effects of the invention) As described above, the micromotor of the present invention has a compact built-in rotary encoder, so the variable range of the rotor's rotational speed is extremely wide, and therefore advanced and diverse applications are possible. The characteristic of being small is maintained as it is,
Moreover, since the rotary encoder is provided on the main body side via the element holder, even if the connection between the main body and the connector section is slightly loose, the optical axis between the light emitting and light receiving elements will not change.
Therefore, the output signal from the light-receiving element is stabilized, and highly accurate rotation speed detection is reliably guaranteed, and its practicality is extremely high.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway vertical sectional view showing a typical example of the micromotor of the present invention, Fig. 2 is a partially cutaway exploded perspective view of the same embodiment, Fig. 3 is a view similar to Fig. 1 of another embodiment, Figures 4A and 4B are schematic diagrams of the rotary encoder section. Explanation of symbols, 1...Main body, 11...Rotor,
111...shaft, 2...connector part, 3...
... Rotary encoder, 30 ... Element holder, 31 ... Rotating slit plate, 32 ... Fixed slit plate, 33 ... Light emitting element, 34 ... Light receiving element,
4...Electrical connection terminal, 41...Connector pin,
42...Reception part, L...Rotor axis, l...
optical axis.

Claims (1)

[Scope of utility model registration request] Main body 1 with built-in rotor 11 and rotor 1
1, the shaft 111 of the rotor 11 is connected to the main body 1 in a detachable manner from the axial direction of the rotor 11.
The shaft 111 extends to the joint surface with the connector portion 2, and the shaft 11
A disc-shaped rotary slit plate 31 is fixed to the main body 1, and a light emitting element 33 and a light receiving element 34 are mounted on the main body 1 with their common optical axis l parallel to the axis L of the rotor 11. An element holder 30 for holding the main body 1 is provided.
A fixed slit plate 32 parallel to the rotary slit plate 31 and facing each other is fixedly interposed between the light emitting element 33 and the light receiving element 34 together with the rotary slit plate 31 on the joint surface or holder 30, Rotating slit plate 31, fixed slit plate 3
2. The rotary encoder 3 is constituted by the light emitting element 33 and the light receiving element 34, and the connector pin 41 and its receiving part 42 are assembled to provide a plurality of electrical connections for the rotor 11, the light emitting element 33, the light receiving element 34, etc. A rotary encoder characterized in that terminals 4 are embedded in the joints of the main body 1 and the connector portion 2, parallel to the axis of the shaft 111 and distal from the rotary encoder 3. Built-in micro motor.