JPS632619B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speed switching mechanism that can be incorporated into dental hand pieces and the like.

In dental treatment instruments, such as micro motors or air motors, cutting tools are attached to the spindle, which is the output shaft.
There are cases where it is desired to change the rotational speed of the spindle due to technical reasons. In such cases, conventionally the speed has been changed by changing the number of poles of the drive motor or changing the air supply amount of the air motor, but these methods do not allow for changing the power energy itself. , it is difficult to obtain the necessary torque.

Furthermore, in the past, a speed switching mechanism using a planetary gear mechanism has been proposed in Japanese Patent Application Laid-open No. 53-129492, but this speed switching mechanism has the following problems. That is, the same speed switching mechanism is provided with a rotary disk that can rotate concentrically with respect to the input shaft, and a planetary gear supported by this rotary disk is meshed with a ring gear fixed to the treatment instrument main body, so that the input shaft and A conductive member and a ball which are externally operated are interposed between the rotary disk. Therefore, according to this speed switching mechanism, power is transmitted either through the planetary gear mechanism or not through the planetary gear mechanism by selecting the position of the transmission member.
It is necessary to precisely machine the petal-shaped grooves for receiving the plurality of balls on the peripheral surface of the input shaft and the inner peripheral surface of the rotary disk, which results in relatively high manufacturing costs. It is difficult to change the speed of the ball unless it completely faces the groove, so when changing the speed, it is necessary to slightly rotate the output shaft by hand, etc., making the operation difficult and causing local stress. Concentration tends to cause scratches and deformation on the ball and groove, making it impossible to perform speed switching operations smoothly.
There is a problem with high failure frequency.

In view of the actual situation of the speed switching mechanism of conventional dental treatment instruments as described above, the present invention does not require precision machining that is expensive to manufacture, and even if some damage or deformation occurs to the internal mechanism, Aiming at obtaining a failure-free structure, the present invention can be summarized as follows: a sun gear supported on a drive shaft, supported on a pin mounted on a rotating disk connected to a spindle; In a dental treatment instrument equipped with a speed conversion mechanism having a planetary gear meshed with the sun gear and a ring gear meshed with these planetary gears, the ring gear movable in the length direction of the drive shaft a clutch cylinder that is movably positioned integrally with the ring gear so as to be able to freely rotate relative to the drive shaft but not rotate relative to the drive shaft; and a head of the pin that is engageable and detachable with respect to the clutch cylinder. Department and
When the ring gear is in a first position where rotational movement is prevented, the clutch barrel and the pin head are disengaged, and when the ring gear is in a second position where it is freely rotatable, the clutch is The speed switching mechanism includes a cylinder and a manual operating means for engaging the pin head.

Hereinafter, the present invention will be explained in detail with reference to embodiments shown in the drawings.

Although the illustrated embodiment is an example in which the present invention is applied to an air motor, it is clear that the present invention is applicable to other dental treatment instruments such as micro motors.

Fig. 1 is an external view of a dental air motor to which the present invention is applied, and the base of the casing A has a forward/reverse switch that can switch the direction of compressed air by rotating with respect to the casing A. Knob B is supported.

The casing A is provided with a speed switching knob C, and by manually operating the speed switching knob C, the rotational speed of the spindle D protruding from the tip of the casing A can be switched.

FIG. 2 is an enlarged sectional view of the same dental air motor, in which an air supply pipe 1 connected to a compressed air source (not shown) is fixed to the forward/reverse switching knob B.
A passage 2 connected to the air supply pipe 1 has a switching opening 3 that opens in the radial direction. A guide pin 4 is installed in the forward/reverse switching knob B, and the tip of the guide pin 4 is located in a long hole 6 having a length of 1/4 arc formed in the end wall 5 of the casing A. Therefore, as will become clear from the description below, when the guide pin 4 is located at one end of the elongated hole 6,
When the spindle D is rotated in the normal direction and the guide pin 4 is positioned at the other end of the elongated hole 6, the spindle D is rotated in the reverse direction.

Furthermore, a pair of partition walls 7 and 8 are incorporated inside the casing A, and a rotating shaft 9 is rotatably supported by these partition walls 7 and 8. A rotor 10 is fixed to the rotating shaft 9, and a pair of impulse vanes 11 and 12 are formed on the circumferential surface of the rotor 10 at different positions in the axial direction. These impulse vanes 11 and 12 are provided in opposite directions in the direction of rotation, as shown in FIG.

The outer peripheral surface of the peripheral wall 8a of the partition wall 8 and the casing A
Between the inner circumferential surfaces of the
is formed. These air chambers 13a, 13b,
As shown in FIGS. 3 and 4, the air chambers 14a and 14b are directly opposed to each other in the radial direction, and the air chambers 13a and 13b have injection nozzles that are opened at positions corresponding to the impulse blades 12. 15 is connected to the air chambers 14a and 14b, and an injection nozzle 16 that is located at a different position in the axial direction from the injection nozzle 15 and that corresponds to the impulse vane portion 11 is connected to the air chambers 14a and 14b. And the air chambers 13a, 13b, 14a, 14
b is connected to communication passages 17a and 17b opened in the movement locus range of the switching port 3. Therefore, when the switching port 3 is in the position shown by the solid line as shown in FIG. 3, compressed air is fed into the air chambers 13a and 13b, and the rotor 10 is rotated in the normal direction. Furthermore, when the switching port 3 is switched to the position shown by the two-dot chain line, compressed air is sent into the air chambers 14a and 14b, and the rotor 10
When the rotation is reversed and the switching port 3 is in the position shown by the one-dot chain line, the compressed air is cut off and the rotor 10 is stopped.

The rotational movement of the rotating shaft 9 is decelerated by a deceleration mechanism D built into the center of the casing A. A sun gear 18 fixed to the rotating shaft 9 is meshed with a planetary gear 21 supported by a pin 20 of a rotating disk 19. Further, these planetary gears 21 are meshed with a ring gear 22 fixed to the casing A. Therefore, the sun gear 18, the planet gear 21,
The rotating shaft 9 can be rotated by selecting the tooth ratio of the ring gear 22.
The rotational motion of is decelerated to a fraction of that.

A speed switching mechanism E according to the present invention is incorporated into the casing A, which can perform speed switching using a speed switching knob C. Speed switching mechanism E
comprises a sun gear 24 integrated with a drive shaft 23 that can rotate integrally with the rotary disk 19,
A clutch cylinder 26 pressed by a spring 25 is fitted into the non-circular cross section 23a of the drive shaft 23 so that it can slide in the axial direction of the drive shaft 23 and rotate integrally with the drive shaft 23. The rotary disk 27 integrated with the spindle D has a plurality of pins 28 installed on its end surface, and a plurality of planetary gears 29 rotatably supported by these pins 28 are connected to the sun gear 24. are engaged. A ring gear 30 meshed with the planetary gears 29 is positioned around the planetary gears 29 described above. This ring gear 30 having a tapered portion 30a is
It is supported by a bearing 31 so that it can move integrally with the clutch cylinder 26 in the axial direction of the drive shaft 23 and freely rotate with respect to the clutch cylinder 26.

Inside the casing A, there is an inner tapered member 3.
2 is fixed. Also, sleeve A connects casing members A1 and A2 that constitute casing A.
3, a speed switching knob C is fitted so that it can rotate freely, and a sleeve A shown in FIG.
The head of the operating pin 35 located in the inclined elongated hole 34 of No. 3 is located. The tips of these operating pins 35 are located in the annular groove 36 of the ring gear 30, so that when the operating pins 35 are moved to the position shown in the second figure by the speed switching knob C, the rings - The tapered portion 30a of the gear 30 is fixed by the inner tapered member 32.

Meanwhile, the clutch tube 26 has radial pawls 38 between which the head 37 of the pin 28 can be received. Therefore, the operating pin 35 is moved by the speed switching knob C to the position shown in FIG.
When released, the head 37 of the pin 28 engages the pawl 38.

The compressed air that rotates the rotor 10 cools each of the aforementioned movable members, and then is discharged to the atmosphere. That is, a part of the compressed air that rotated the rotor 10 is
A hole 39 bored in the partition wall 8 and the forward/reverse switching knob B,
40 to the outside from the base of the air motor. The remaining compressed air then flows through the holes 41 of the partition wall 7.
After passing through the hole 42 of the ring gear 22 and the bearing 31 to cool the speed switching mechanism E, it passes through the bearing 43 that supports the spindle D and is discharged to the outside of the machine.

Since the air motor of the above embodiment has the structure as described above, when the operating pin 35 is moved to the position closest to the right as shown in FIG.
Tapered portion 30a of ring gear 30 engages inner tapered member 32, and ring gear 30 is fixed to casing A. For this purpose, the speed switching mechanism E
functions as a normal planetary gear reduction mechanism, and the spindle D is rotated at a speed reduced to a fraction of that of the drive shaft 23.

Further, when the speed switching knob C is rotated, the operating pin 35 moves along the oblique elongated hole 34 of the sleeve A3 toward the position shown in the sixth figure. That is, when the operating pin 35 is moved to the position shown in FIG. 6, the tapered portion 30a of the ring gear 30 is disengaged from the inner tapered member 32, and the ring gear 30 is in a state where it can freely rotate. Also, in this state, pin 2
The head 37 of the clutch cylinder 26 is engaged with the pawl 38 of the clutch cylinder 26, and the rotational movement of the drive shaft 23 is controlled by the clutch cylinder 26,
Since the power is directly transmitted to the spindle D via the pin 28 and the rotary disk 27, the spindle D is rotationally driven at the same speed as the drive shaft 23.

As is clear from the above description, according to the present invention, the power is switched by engaging and disengaging the clutch cylinder and the pin of the planetary gear, so compared to the speed switching mechanism described in the above-mentioned Japanese Patent Application Laid-Open No. 53-129492, Precision machining is not required, speeds can be changed rapidly, and a structure with a low failure rate can be obtained. In other words, since a sufficient meshing gap can be formed between the clutch cylinder and the pin of the planetary gear according to the present invention, the manufacturing cost is low, and the same gap allows the two to be engaged and disengaged in any state. Since the gap between the pin head and the clutch tube can be designed to be large, even if the pin head or clutch tube is damaged, it will not cause a failure.

[Brief explanation of the drawing]

Fig. 1 is an external view of an air motor incorporating the present invention, Fig. 2 is an enlarged sectional view of the air motor, and Fig. 3 is an enlarged sectional view of the air motor.
The figure is a sectional view taken along line - in Fig. 2, Fig. 4 is a partially cutaway sectional view taken along line - - in Fig. 2, and Figs. 5 and 6 are explanations of the operation of the speed switching mechanism. 7 are cross-sectional views of the sleeve. 23... Drive shaft, 24... Sun gear, 26... Clutch cylinder, 27... Rotating disk, 28... Pin, 30...
Ring gear, 32...inner tapered member, 35...operating pin, 37...head, 38...pawl, C...speed switching knob, D...spindle.

Claims (1)

[Claims] 1. A speed having a sun gear supported on a drive shaft, planetary gears supported on pins planted in a rotating disk connected to the spindle and meshed with said sun gear, and a ring gear meshed with these planetary gears. In a dental treatment device equipped with a conversion mechanism,
a clutch cylinder that is movably positioned integrally with the ring gear such that it can freely rotate with respect to the ring gear that is movable in the length direction of the drive shaft, but cannot rotate with respect to the drive shaft; , when the head of the pin that is removably engageable with the clutch tube and the ring gear are in a first position where rotational movement is prevented, the clutch tube and the head of the pin are disengaged; The second ring gear can rotate freely.
a speed switching mechanism comprising manual operating means for engaging said clutch barrel and said pin head when in position .