JP2000035102A - Variable reduction ratio type reduction gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a large change of reduction ratio in the case of approaching and in the case of returning by selectively taking the rotary output from an epicyclic gear mechanism and the rotary output from a Ferguson mechanism. SOLUTION: A pulse motor 1 capable of being rotated normally and reversely is fixed to an outside end surface of an input side case 2 provided with an inner gear, and an input shaft 3 is extended inward of the input side case 2, and a pinion 4 is fixed to the input shaft 3. Three epicyclic gears 6 to be engaged with the pinion 4 and while commonly engaged with an inner gear of the input side case 2 and an inner gear of a rotor 12 are arranged in the periphery of the pinion 4 with an equal space, and installed between two rotary support plates 7 freely to be rotated by each support shaft 19, and a Ferguson mechanism is thereby structured. The rotary output from the Ferguson mechanism and the rotary output from the epicyclic gear mechanism are selectively taken out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed reduction ratio variable speed reducer, in which a reduction ratio with respect to an output shaft is changed by changing a rotation direction of an input shaft.

[0002]

2. Description of the Related Art For example, when a piston of a dispenser is reciprocated by using a stepping motor, there is a case where it is desired to change the speed of the piston between a forward movement and a backward movement. It is considered that the pulse rate of the stepping motor for driving the piston is changed between the forward movement and the backward movement.

In this case, for example, during the forward movement of the piston (when discharging the content liquid from the dispenser), the piston must be driven at a low speed in relation to its operation, but the overall operation time is shortened. Due to necessity, there is a case where it is necessary to drive at a high speed at the time of backward movement, in this case, the pulse rate is made small at the time of forward movement driving the piston at low speed, and at the time of backward movement driving the piston at high speed, There is a way to increase the rate.

[0004]

In the prior art as described above, a high-speed stepping motor is required in order to increase the speed at the time of return movement because of the necessity of shortening the entire operation time. However, if this high-speed type stepping motor is driven with a small pulse rate, there is a possibility that vibrations may occur and it may be difficult to send out the piston smoothly.

Further, when the stepping motor is driven at a high speed, there is a possibility that the specification becomes overspec. Furthermore,
A control circuit for smoothly changing the speed from a low speed to a high speed is also required.

SUMMARY OF THE INVENTION The present invention solves the problems of the prior art, in which the rotation speed of the output shaft is changed without difficulty by changing the rotation direction of the motor without changing the rotation speed of the motor. It is intended to operate smoothly even at low speeds.

[0007]

According to a first aspect of the present invention, there is provided a pinion fixed to an input shaft, a planetary gear meshing with the pinion and revolving around the pinion, and meshing with the planetary gear and located around the pinion. A planetary gear mechanism constituted by a fixed internal gear, and a Ferguson mechanism comprising a rotating internal gear opposed to the fixed internal gear and meshing with the planetary gear, wherein the rotation output from the planetary gear mechanism and the ferguson A speed reduction ratio variable speed reducer characterized in that rotational output from a mechanism is selectively taken out.

In the present invention, the rotation output from the planetary gear mechanism and the rotation output from the Ferguson mechanism that can provide a large reduction ratio are selectively extracted. If the output from the planetary gear mechanism is sometimes used, the reduction ratio can be greatly changed between the forward movement and the backward movement.

The second invention is based on the first invention. When the input shaft rotates in one direction, the rotation output from the planetary gear is taken out, and when the input shaft rotates in the other direction, the rotation output is obtained. Is a speed reduction ratio variable speed reducer from which the rotational output from the Ferguson mechanism is taken out.

In the present invention, the rotation output is taken out from the planetary gear when the input shaft rotates in one direction, and from the Ferguson mechanism when it goes in the other direction.

Therefore, when the input shaft rotates in the other direction, the output shaft rotates at a low speed, and when the input shaft rotates in one direction, the output shaft rotates at a high speed.

A third invention is based on the first invention or the second invention, and the output shaft is screwed into the output side of the planetary gear mechanism so as to be able to be inserted and withdrawn, and the input shaft rotates in one direction. In this case, the output shaft is screwed into the output side of the planetary gear mechanism, the rotational force from the input shaft is transmitted to the output shaft via the planetary gear mechanism, and the input shaft rotates in the other direction. In this case, the output shaft is removed from the output side of the planetary gear mechanism, and the rotational force from the input shaft is cut off.

According to the present invention, when the input shaft is rotating in one direction, the output shaft is screwed into the output side of the planetary gear mechanism, and the rotational force from the input shaft is transmitted via the planetary gear mechanism. When the output shaft is transmitted to the output shaft and the input shaft rotates in the other direction, the output shaft is withdrawn from the output side of the planetary gear mechanism and the rotational force from the input shaft is cut off. When rotating in one direction, the output shaft rotates at high speed.

The fourth invention is based on the third invention, and when the input shaft rotates in the other direction, the output shaft is pulled out from the output side of the planetary gear mechanism, so that the output from the Ferguson mechanism is reduced. This is a speed reduction ratio variable speed reducer in which rotation output is transmitted to an output shaft.

In the present invention, when the input shaft rotates in the other direction, the output shaft is removed from the output side of the planetary gear mechanism, so that the rotation output from the Ferguson mechanism is transmitted to the output shaft. When the input shaft is rotating in the other direction, the output shaft rotates at low speed.

The fifth invention is based on the fourth invention, and a one-way clutch is interposed between the output side of the Ferguson mechanism and the output shaft, when the input shaft is rotating in the other direction. Only the reduction ratio variable speed reducer in which the rotational force from the Ferguson mechanism is transmitted to the output shaft.

In the present invention, the rotational force from the Ferguson mechanism is transmitted to the output shaft by the one-way clutch only when the input shaft is rotating in the other direction, and does not interfere with the planetary gear mechanism.

[0018]

1 is a longitudinal sectional view of a mode in which an input shaft rotates in one direction, and FIG. 2 is a partially cutaway view corresponding to the mode of FIG. It is a perspective view. 3 and 4 are partially cutaway perspective views of a mode in which the input shaft rotates in the other direction. FIG. 5 is a longitudinal sectional view of a syringe unit in which the present embodiment is applied to a dispenser.

In FIG. 1, reference numeral 1 denotes a forward / reverse rotatable pulse motor, which is fixed to an outer end surface of an input side case 2 in which an internal gear is cut, and an input shaft 3 is connected to the input side case 2.
And a pinion 4 is fixed to the input shaft 3.

An output case 5 is fixedly opposed to the input case 2 on the side opposite to the fixed side of the pulse motor 1, and a convex rotor 12 is provided inside the output case 5.
Is rotatably accommodated via a bearing 13.

On the inner surface of the large-diameter portion of the rotor 12, an internal gear having the same pitch circle diameter as the internal gear of the input side case 2, but having a slightly different number of teeth is cut.

Around the pinion 4, three planetary gears 6, 6, 6 meshing with the pinion 4 and commonly meshing with the internal gear of the input side case 2 and the internal gear of the rotor 12 are provided. Are disposed at equal intervals, and are rotatably mounted between the two rotation support plates 7 and 7 (see FIG. 5) by support shafts 19, respectively.

A female screw 8 is formed at the center of the rotation support plate 7, and an output shaft 9 rotatably supported by the female screw 8 on the output side case 5 via a bearing 14. Transmission shaft 10 slidably inserted inside
A male screw 11 cut in the vicinity of the inner end of the screw hole is screwed into and out of the hole.

The male screw 11 is screwed into the female screw 8 of the rotary support plate 7 when the input shaft 3 rotates clockwise (one direction) and the rotary support plate 7 also rotates clockwise. It is configured to be.

Thus, the pinion 4, the planetary gear 6,
A planetary gear mechanism is constituted by 6, 6 and the internal gear of the input side case 2, and when an internal gear of the rotor 12 is added thereto, a so-called Ferguson mechanism is constituted.

As is well known, the Ferguson mechanism is extremely high in this embodiment by reducing the difference between the number of teeth of the internal gear of the input case 2 and the number of teeth of the internal gear of the rotor 12. A reduction ratio can be obtained.

That is, the rotation output of the rotation support plate 7 is the rotation speed based on the reduction ratio of the planetary gear mechanism, and the rotation output of the rotor 12 is the rotation speed based on the high reduction ratio of the Ferguson mechanism.

A spline is cut into the inner surface of the small diameter portion of the rotor 12, and a spline gear 15 meshing with the spline of the rotor 12 is mounted on the transmission shaft 10 via a one-way clutch 16.

The one-way clutch 16 includes the input shaft 3
When the transmission shaft 10 rotates clockwise and the transmission shaft 10 rotates clockwise integrally with the rotation support plate 7, the rotational force of the transmission shaft 10 is not transmitted to the spline gear 15.

Further, a spline similar to the spline of the rotor 12 is also cut inside the vicinity of the base end of the output shaft 9, and the spline is provided outside the spline gear 15 of the transmission shaft 10. A convex spline gear 17 similar to the spline gear 15 is slidably mounted only in the axial direction.

A compression coil spring 18 for pressing the spline gear 17 inward is provided around the transmission shaft 10 outside the spline gear 17.

Therefore, when the input shaft 3 rotates clockwise in the state shown in FIGS. 1 and 2, the planetary gear mechanism reduces the speed by a predetermined reduction ratio, and the rotation support plate 7 rotates clockwise, thereby transmitting the rotation. The shaft 10 rotates clockwise, and its rotational force is transmitted to the output shaft 9 via a spline gear 17 and a spline of the output shaft 9, and the output shaft 9 is fixed to the input shaft 3 by a planetary gear mechanism. The clockwise rotation is performed at the rotation speed reduced by the reduction ratio of.

In this case, as described above, since the one-way clutch 16 is interposed between the transmission shaft 10 and the spline gear 15 meshing with the spline of the rotor 12, the transmission between the spline gear 15 and the transmission shaft 10 is performed. The shaft 10 rotates relatively, and the rotor 12 and the transmission shaft 10 are mechanically insulated.

Next, based on FIG. 3 and FIG.
Are reversed, and the mode in which the input shaft 3 rotates counterclockwise (other direction) will be described.

When the input shaft 3 rotates counterclockwise,
The speed is reduced by a predetermined reduction ratio by the planetary gear mechanism, so that the rotation support plate 7 also rotates in the counterclockwise direction.
When the transmission shaft 10 rotates in the counterclockwise direction, the rotational force is transmitted to the spline gear 15 and the spline of the rotor 12 via the one clutch 16. Since the rotor 12 is much slowed down by the Ferguson mechanism compared to the planetary gear mechanism, the resistance becomes extremely large, so that the rotation of the spline gear 15 and the transmission shaft 10 in the counterclockwise direction is prevented. Become.

Then, the rotation support plate 7 rotates counterclockwise while the transmission shaft 10 is stopped, and the male screw 11 of the transmission shaft 10 is removed from the female screw 8 of the rotation support plate 7. Then, the transmission shaft 11 moves outward inside the output shaft 9 while compressing the compression coil spring 18.

As shown in FIG. 4, when the male screw 11 of the transmission shaft 10 is completely removed from the female screw 8 of the rotation support plate 7, the transmission shaft 10 and the rotation support plate 7 are mechanically insulated. The spline gear 17 is separated from the spline of the output shaft 9 and the spline gear 15 simultaneously meshes with both the spline of the output shaft 9 and the spline of the rotor 12.

Then, the output shaft 9 rotates integrally with the rotor 12. When the input shaft 3 rotates counterclockwise, the output shaft 9 is further decelerated and further decelerated by the Ferguson mechanism, and the transmission shaft 10 is rotated counterclockwise. Will rotate.

By appropriately selecting the difference between the number of teeth of the internal gear of the rotor 12 and the number of teeth of the internal gear of the output side case 2, the output shaft 9 can be rotated even if the input shaft 3 is rotated counterclockwise. It is also possible to rotate clockwise.

When the pulse motor 1 is rotated forward again, the resilient force of the compression coil spring causes the transmission shaft 1 to rotate.
In the state in which the male screw 11 of the 0 bites into the female screw 8 of the rotation support plate 7 and starts screwing, and the screwing is completed, FIG.
Returning to the mode shown in FIG.

Therefore, if the input shaft 3 is rotated counterclockwise without changing the rotation speed of the pulse motor 1, the output shaft 9 is rotated at a low speed by the Ferguson mechanism, and the input shaft 3 is rotated clockwise. Then, the output shaft 9 is rotated at a relatively high speed by the planetary gear mechanism.

Next, the syringe unit will be described with reference to FIG. The same parts as those in the embodiment of FIG. 1 are denoted by the same reference numerals, and detailed description is omitted.

In addition to the Ferguson mechanism, a syringe 20 for dispensing a reagent or blood is provided in parallel with the output side case 5, and an auxiliary case 21 is provided facing the output side case 5. I have.

The extension end of the output shaft 9, on which the feed screw portion 22 is screwed on the outer periphery of the extension portion, is rotatably held in the auxiliary case 21. , A plurality of support shafts 23 are provided.

A nut 24 is rotatably slidably mounted on the feed screw portion 22 of the output shaft 9.
4 and the piston shaft 26 of the syringe 20
Is connected to the outside end.

Accordingly, when the input shaft 3 of the pulse motor 2 rotates in one direction, the output shaft 9 rotates at a relatively high speed as described above, and accordingly, the piston shaft 26 of the syringe 20 together with the nut 24 is rotated. The syringe 20 is withdrawn at a high speed, and the syringe 20 is rapidly filled with the liquid.

When the input shaft 3 rotates in the other direction, the output shaft 9 rotates at a low speed in the same manner as described above, and the piston shaft 26 of the syringe 20 is inserted into the syringe 20 at a low speed. The filled liquid is discharged slowly.

[0048]

According to the first aspect of the present invention, the rotation output from the planetary gear mechanism and the rotation output from the Ferguson mechanism capable of obtaining a large reduction ratio are selectively extracted. However, if the output from the planetary gear mechanism is used during the backward movement, the reduction ratio can be greatly changed between the forward movement and the backward movement.

In the second aspect, the rotation output is taken out from the planetary gear when the input shaft rotates in one direction, and from the Ferguson mechanism when it turns in the other direction.

Therefore, when the input shaft rotates in the other direction, the output shaft rotates at a low speed, and when the input shaft rotates in one direction, the output shaft rotates at a high speed.

In the third aspect, when the input shaft is rotating in one direction, the output shaft is screwed into the output side of the planetary gear mechanism, and the rotational force from the input shaft is transmitted to the planetary gear mechanism. When the input shaft rotates in the other direction, the output shaft is removed from the output side of the planetary gear mechanism and the rotational force from the input shaft is cut off. When the shaft is rotating in one direction, the output shaft will rotate at high speed.

In the fourth aspect, when the input shaft rotates in the other direction, the output shaft is withdrawn from the output side of the planetary gear mechanism, whereby the rotation output from the Ferguson mechanism is transmitted to the output shaft. Therefore, when the input shaft is rotating in the other direction, the output shaft rotates at low speed.

According to the fifth aspect of the invention, the rotational force from the Ferguson mechanism is transmitted to the output shaft by the one-way clutch only when the input shaft is rotating in the other direction, and does not interfere with the planetary gear mechanism.

As described above, in any of the inventions,
Since the planetary gear mechanism and the Ferguson mechanism that can provide a large reduction ratio can be appropriately selected, the problem that vibration is generated by driving a high-speed stepping motor with a small pulse rate as in the related art can be solved.

Therefore, there is no risk of over-spec, an expensive current switching circuit and an associated control circuit are not required, and the reliability is improved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a mode in which an input shaft rotates in one direction according to an embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view of a mode in which an input shaft rotates in one direction according to an embodiment of the present invention.

FIG. 3 is a partially cutaway perspective view of a mode in which an input shaft rotates in another direction according to an embodiment of the present invention.

FIG. 4 is a partially cutaway perspective view of a mode in which an input shaft rotates in another direction according to an embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of a mode in which an input shaft rotates in one direction according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pulse motor 2 Input side case 3 Input shaft 4 Pinion 5 Output side case 6 Planetary gear 7 Rotation support plate 8 Female screw 9 Output shaft 10 Transmission shaft 11 Male screw 12 Rotor 13 Bearing 14 Bearing 15 Spline gear 16 Clutch 17 Spline gear 18 Compression coil spring 19 Support shaft 20 Syringe 21 Auxiliary case 22 Feed screw part 23 Support shaft 24 Nut 25 Extension arm 26 Piston shaft

Claims (5)

[Claims] 1. A planetary gear comprising a pinion fixed to an input shaft, a planetary gear meshing with the pinion and revolving around the periphery thereof, and a fixed internal gear meshing with the planetary gear and located around the planetary gear. And a Ferguson mechanism comprising a rotating internal gear opposed to the fixed internal gear and meshing with the planetary gear.The rotational output from the planetary gear mechanism and the rotational output from the Ferguson mechanism are selectively taken out. A variable reduction ratio reduction device characterized by the following: 2. A rotation output from a planetary gear is taken when the input shaft rotates in one direction, and a rotation output from a Ferguson mechanism is taken when the input shaft rotates in the other direction. The variable reduction ratio reduction device according to any one of the preceding claims. 3. The output shaft is threadably inserted into and removed from the output side of the planetary gear mechanism. When the input shaft is rotating in one direction, the output shaft is connected to the output side of the planetary gear mechanism. The rotational force from the input shaft that is screwed in is transmitted to the output shaft via the planetary gear mechanism, and when the input shaft rotates in the other direction, the output shaft is removed from the output side of the planetary gear mechanism. 3. The rotation force from the input shaft is cut off.
The variable reduction ratio reduction device according to any one of the preceding claims. 4. The rotation output from the Ferguson mechanism is transmitted to the output shaft by removing the output shaft from the output side of the planetary gear mechanism when the input shaft rotates in the other direction. Variable speed reduction gearbox. 5. A one-way clutch is interposed between the output side of the Ferguson mechanism and the output shaft, and the rotational force from the Ferguson mechanism is applied to the output shaft only when the input shaft is rotating in the other direction. 5. The speed reduction ratio variable speed reducer according to claim 4, wherein the speed reduction ratio is transmitted.