Planetary geared reducer with dual reduction ratio

Provided is a planetary geared reducer with a dual reduction ratio. The reducer includes: a housing provided with a ring gear, and having one side where an input shaft is rotatably inserted and an opposite side where an output shaft is rotatably inserted; a sun gear provided at the input shaft; at least one planetary gear engaged between the sun gear and the ring gear; and a high reduction carrier provided at the output shaft to rotatably support the planetary gear by a rotation pin, wherein the high reduction carrier is coupled with a low reduction carrier, the low reduction carrier has a through-hole where the sun gear passes, the through-hole has a low reduction gear engaged with the sun gear, and the sun gear is selectively interlocked with the planetary or low reduction gear according to a forward or rearward movement of the input shaft to perform dual reduction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a reducer, and more particularly, to a planetary geared reducer with a dual reduction ratio, which has a structure capable of providing an output with different reduction ratios for one input.

2. Description of the Related Art

In general, various devices such as machine tools, washing machines, and automobiles require reducers that use various gears to vary a rotation ratio. The reducer is a device that receives a rotational force from a power source such as a motor that rotates at a considerable speed and converts the received rotational force to have a low speed in order to output the low-speed rotational force, in which an assembly of various types of gears is used in the reducer.

Among the reducers, a reducer that increases the power transmission efficiency by reducing a load and a speed transmitted from an input shaft to an output shaft by using planetary gears is widely used in every fields of industry such as shipbuilding, offshore plants, power plants, and industrial plants.

In particular, such a reducer is frequently used for actuators such as valves and valve gearboxes, and the reducer is important when opening, closing, or operating a valve.

FIG. 1is a sectional view showing the structure of a reducer using a planetary gear according to the related art.

As shown in the drawing, the reducer according to the related art includes: a gear housing having an internal gear; an input shaft having one end connected to a motor shaft and an opposite end inserted into an input side of the gear housing; a sun gear coupled to the opposite end of the input shaft; a plurality of planetary gears simultaneously engaged with the sun gear and the internal gear of the gear housing; and a rotation plate provided at a lower portion thereof with a plurality of connection pins which are fitted to centers of the planetary gears, and provided at an upper center thereof with an output shaft.

With such a configuration, when the input shaft is rotated by receiving a rotational force from a motor, the planetary gears engaged with the input shaft rotate around the input shaft while rotating on their axes, and the rotation plate rotates at a rotation speed of the planetary gear rotating around the input shaft, so that the rotational force is output through the output shaft after being reduced.

However, since the reducer according to the related art has a simple configuration but has only one reduction rotation ratio, two or more types of reduction ratios may not be realized.

In addition, in order to provide two or more types of reduction ratios, the structure becomes very complicated and bulky, and in particular, an output shaft corresponding to each of the reduction ratios has to be provided separately.

In the case of a valve, a large torque is required at the start and end of a stroke during opening and closing of the valve, so it is necessary to increase the reduction ratio at the start and end of the stroke. However, the large torque is not required in the middle of the stroke, so it is necessary to increase an operating speed by reducing the reduction ratio.

As a result, the reducer according to the related art could not satisfy such demands at all.

DOCUMENTS OF RELATED ART

SUMMARY OF THE INVENTION

Accordingly, to solve the problems described above, one object of the present invention is to provide a planetary geared reducer with a dual reduction ratio, which has a structure capable of selectively providing an output with different reduction ratios for one rotation speed input.

Another object of the present invention is to provide a planetary geared reducer with a dual reduction ratio, which has a structure in which one output shaft may provide an output with different reduction ratios, and an input shaft and the output shaft may be concentric with each other.

To achieve the objects described above, according to the present invention, there is provided a planetary geared reducer with a dual reduction ratio, the planetary geared reducer including: a housing having a cylindrical shape, provided on an inner circumferential surface thereof with a ring gear in a form of an internal gear, and having one side into which an input shaft is rotatably inserted and an opposite side into which an output shaft is rotatably inserted; a sun gear provided at an end of the input shaft; at least one planetary gear engaged between the sun gear and the ring gear; and a high reduction carrier provided at an end of the output shaft to rotate and configured to rotatably support the planetary gear by a rotation pin, wherein the high reduction carrier is coupled with a low reduction carrier for covering the planetary gear to accommodate the planetary gear therein, the low reduction carrier has a through-hole through which the sun gear passes, the through-hole is provided on an inner circumferential surface thereof with a low reduction gear in a form of an internal gear which is engaged with the sun gear, and the sun gear is selectively interlocked with the planetary gear or the low reduction gear according to a forward or rearward movement of the input shaft to perform dual reduction.

In this case, a guide rod may protrude from a center of the high reduction carrier, the input shaft may be formed at a center thereof with a guide hole into which the guide rod is inserted, and centers of the guide rod and the guide hole may match centers of the input shaft and the output shaft to guide a movement of the input shaft.

In this case, the planetary geared reducer may further include a restoration spring provided between the guide hole and the guide rod to move the input shaft rearward.

In addition, the input shaft may be formed at an outer circumference thereof with a latching groove, and the housing may be provided on one side thereof with a latching pin which is inserted into the latching groove.

In addition, the latching pin may be elastically supported by a latching spring.

Meanwhile, the planetary geared reducer may further include a first reduction device mounted between the high reduction carrier and the low reduction carrier, and the first reduction device may include: a first sun gear engaged with the planetary gear; a first reduction carrier spline-coupled to the first sun gear; at least one first planetary gear rotatably coupled to the first reduction carrier by a first rotation pin and engaged with the sun gear; and a first housing coupled between an input side housing and an output side housing divided from the housing, and provided on an inner circumferential surface thereof with a first ring gear engaged with the first planetary gear, wherein the first rotation pin may be coupled to the low reduction carrier, and the rotation pin may be coupled with a first auxiliary carrier for preventing the planetary gear from being separated.

In this case, the planetary geared reducer may further include a second reduction device mounted between the first reduction device and the low reduction carrier and having a configuration identical to a configuration of the first reduction device.

According to the present invention having the above-described configuration, first, while two types of reduction ratios are provided, the structure is simple and has a small volume, so that miniaturization and weight lightening can be achieved.

Second, when the present invention is applied to the opening and closing of a valve, a high reduction ratio is selected at the start and end of the opening and closing to generate a large torque, so that the opening and closing can be smoothly performed, and since the large torque is not required in the middle of the opening and closing, a low reduction ratio is selected to increase the operating speed without the large torque, so that the opening and closing can be rapidly performed.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, one embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

For reference, the description with reference to the drawings is provided for better understanding of the present invention, so the scope of the present invention is not limited thereto. In addition, throughout the description of the present invention, when the detailed description of a relevant generally-known technology is determined to unnecessarily obscure the subject matter of the present invention, the pertinent detailed description will be omitted.

FIG. 2is a perspective view showing an entire exterior of a planetary geared reducer with a dual reduction ratio according to one embodiment of the present invention, andFIG. 3is a longitudinal sectional view of the present invention shown inFIG. 2.

The present invention is a device such as a gearbox in which a rotational force is reduced when the rotational force is input to an input shaft by a power source such as a motor (not shown) so as to output the reduced rotational force to an output shaft.

One embodiment of the present invention may generally include a housing10, an input shaft20, an output shaft30, a planetary gear40, a sun gear50, a high reduction carrier60, and a low reduction carrier70.

The housing10may accommodate and support the input shaft20, the output shaft30, the planetary gear40, the sun gear50, the high reduction carrier60, and the low reduction carrier70.

The housing10may have a substantially cylindrical shape, and may be divided into an input side housing11and an output side housing13so as to be disassembled and assembled.

In this case, the input side housing11and the output side housing13may be fastened to each other at edges thereof by a plurality of fastening bolts16.

In addition, the input side housing11may have an input port12into which the input shaft20is inserted, and the output side housing13may have an output port14into which the output shaft30is inserted.

Further, a ring gear15, which is an internal gear, may be provided on an inner circumferential surface of the housing10. Preferably, the ring gear15may be provided on an inner circumferential surface of the output side housing13.

Next, the input shaft20and the output shaft30will be described.

The input shaft20may be inserted into the input port of the housing10and rotated by various power sources.

A bushing and an O-ring may be inserted between the input shaft20and the input port12so that the input shaft20may be rotatable, and a sealing effect may be achieved. In addition, the input shaft20may be slidably operated to move forward or rearward along the input port12.

The output shaft30may be rotatably inserted into the output port14of the housing10.

To this end, a bearing b may be provided between the output shaft30and the output port14, and an O-ring may be provided between the output shaft30and the output port14for the sealing effect. In addition, the output shaft30may have a hollow structure or a solid structure.

Next, the sun gear50and the planetary gear40will be described.

The sun gear50may be coupled to an end of the input shaft20to rotate by the rotation of the input shaft20. The sun gear50may be formed at an outer circumference thereof with gear teeth.

In addition, at least one planetary gear40may be engaged around an outer side of the sun gear50.

Generally, two to four planetary gears40may be arranged at regular intervals, and may be interlocked with each other by the rotation of the sun gear50so as to be rotated in the same direction at the same speed.

In addition, each of the planetary gears40may be engaged with the ring gear.

Therefore, since the planetary gears40are rotated when the sun gear50rotates, and the planetary gears40are interlocked with the ring gear15, the planetary gears40may also move along the ring gear15in a circular trajectory. As a result, the planetary gears40may rotate around the sun gear50while rotating on their axes.

In this case, each of the planetary gears40may be rotatably fixed on the high reduction carrier60and the low reduction carrier70, which will be described below, by an additional rotation pin41.

Next, the high reduction carrier60and the low reduction carrier70will be described.

The high reduction carrier60may be coupled to or provided at an end of the output shaft30to rotate together with the output shaft30.

The high reduction carrier60may substantially have a disc shape, and may be formed at a center thereof with a seating groove61into which the end of the input shaft20may be inserted. In addition, the seating groove61may be provided therein with a bearing b for rotatably supporting the input shaft20having the end inserted into the seating groove61.

In addition, rotation pins41may be vertically fixed to the high reduction carrier60at regular intervals in a circumferential direction, and the planetary gears40may be rotatably coupled to and supported by the rotation pins41, respectively.

Therefore, the high reduction carrier60may be rotated as the planetary gears40rotate, and thus the output shaft30may also be rotated.

Meanwhile, the low reduction carrier70may be coupled to the high reduction carrier60by the rotation pin41so as to accommodate the planetary gears40therein. Therefore, as the planetary gears40rotate, the low reduction carrier70may also be rotated together with the high reduction carrier60.

For reference, the bearing b may be interposed between the low reduction carrier70and the input side housing11.

The low reduction carrier70may be formed at a center thereof with a through-hole, and the through-hole may be provided on an inner circumferential surface thereof with a low reduction gear71in the form of an internal gear.

In this case, the low reduction gear71may be engaged with the sun gear50. Therefore, the rotational force of the sun gear50may be transmitted to the low reduction carrier70, and thus the high reduction carrier60and the output shaft30may be rotated.

For example, when the sun gear50is engaged with the low reduction gear71and rotates while the input shaft20is moved rearward, the output shaft30may be rotated at the same speed as the input shaft20through the low reduction carrier70and the high reduction carrier60. In other words, the same speed may be transferred without any reduction (reduction ratio of 1:1).

However, when the input shaft20is moved forward so that the sun gear50is engaged with the planetary gears40to rotate, the output shaft30may rotate at a lower speed than the input shaft20through the planetary gears40, the ring gear15, and the high reduction carrier60. That is, the reduction may be performed at a reduction ratio of N:1.

In other words, the sun gear50may be selectively interlocked with the planetary gears40or the low reduction gear71according to a forward or rearward movement of the input shaft20to perform dual reduction.

In the following, another embodiment of the present invention will be described with reference toFIGS. 4 and 5.FIG. 4is a sectional view showing a planetary geared reducer with a dual reduction ratio according to another embodiment of the present invention, andFIG. 5is a view showing an operating state of the present invention shown inFIG. 4.

Another embodiment of the present invention has a structure in which the input shaft20is elastically supported so that the input shaft20may smoothly move rearward in a state where the input shaft20is moved forward.

To this end, a guide rod62having a protruding shape may be provided at an inner center of the high reduction carrier60.

In addition, a guide hole21may be formed at a center of the end of the input shaft20.

In this case, the guide rod62is processed so that the guide rod62may be inserted into the guide hole21.

Therefore, the input shaft20may be slidable concentrically with the output shaft30when the input shaft20moves forward or rearward.

However, the guide hole21is provided with a restoration spring23.

The restoration spring23may be a compression spring, and may have one end seated on an upper end of the guide rod62. Therefore, when the input shaft20is pushed to move forward by an external force, the guide rod62may be inserted into the guide hole21while compressing the restoration spring23so that the sun gear50may be interlocked with the planetary gears40.

On the contrary, when the external force is removed, the input shaft20may be pushed rearward by an elastic force of the restoration spring23so that the sun gear50may be interlocked with the low reduction gear71.

In addition, latching grooves22may be formed continuously on an outer peripheral portion of the input shaft20in the circumferential direction.

Further, a latching pin24may pass through one side of the housing10, particularly, may be provided on the input port12. A front end of the latching pin24may be inserted into the latching groove22, and a rear end of the latching pin24may be elastically supported by a latching spring25.

Therefore, when the input shaft20moves forward, the latching pin24may be pushed out and separated from the latching groove22, and when the input shaft20moves rearward, the latching pin24may be latched to the latching groove22so that the input shaft20may not be moved rearward further.

When the present invention is used for opening and closing a valve, in the middle of a stroke where a large torque is not required, the sun gear50may be interlocked with the low reduction gear71in a state in which the input shaft20is moved rearward, so that the output shaft30may be rapidly rotated at the same speed as an input speed.

However, since a large torque is required at the start and end of the stroke during the opening and closing of the valve, it is necessary to increase the reduction ratio. Therefore, the input shaft20may be moved forward to allow the sun gear50to be interlocked with the planetary gears40, so that the output shaft30may be greatly decelerated.

In the following, still another embodiment of the present invention will be described with reference toFIGS. 6 and 7.FIG. 6is a sectional view showing the structure of a planetary geared reducer with a dual reduction ratio according to still another embodiment of the present invention, andFIG. 7is a view showing an operating state of the present invention shown inFIG. 6.

Still another embodiment of the present invention is for proposing a reducer with a larger reduction ratio, and has a structure in which a first reduction device80is additionally mounted between the high reduction carrier60and the low reduction carrier70. In this case, in order to additionally provide the first reduction device80, the input side housing11and the output side housing13may be separated to mount and connect the first reduction device80therebetween.

In detail, the first reduction device80may include a first sun gear81, a first reduction carrier82, a first planetary gear83, a first housing84, and a first auxiliary carrier85.

The first sun gear81may be provided at an outer circumference thereof with gear teeth, and engaged with the planetary gear40.

The first sun gear81may have one end seated in the seating groove of the high reduction carrier60so as to be supported, and an opposite end provided with a spline so as to be spline-coupled to the first reduction carrier82.

The first reduction carrier82may have a structure and a shape similar to the structure and the shape of the high reduction carrier60.

An opposite end of the first sun gear81may be inserted into a center of the first reduction carrier82in one direction so as to be spline-coupled, and the end of the input shaft20may be inserted into the center of the first reduction carrier82in an opposite direction so as to be seated.

In this case, in order to rotatably support the end of the input shaft20, the bearing b may be interposed between the first reduction carrier82and the input shaft20.

One or more first planetary gears83may be arranged on the first reduction carrier82in the circumferential direction. Each of the first planetary gears83may be rotatably fixed by a first rotation pin86.

In addition, each of the first planetary gears83may be engaged with the sun gear50so that the first planetary gears83may rotate in the same direction at the same speed by the rotation of the sun gear50.

The first housing84may be provided around outer sides of the first planetary gears83.

The first housing84may be formed on an inner circumferential surface thereof with a first ring gear87engaged with the first planetary gears83. The first ring gear87may be in the form of an internal gear.

In order to mount the first housing84, the input side housing11and the output side housing13may be separated, and the first housing84may be assembled and fastened between the input side housing11and the output side housing13.

In addition, one ends of the first rotation pins86may be fixed to the first reduction carrier82, and opposite ends of the first rotation pins86may be fixed to the low reduction carrier70, so that the first reduction carrier82and the low reduction carrier70may rotate together.

For reference, a separate first auxiliary carrier85may be coupled to an opposite end of the rotation pin41that has one end fixed to the high reduction carrier60so as to rotate together with the high reduction carrier60while preventing the planetary gear40from being separated.

Referring to an operating state, when the input shaft20is moved rearward so that the sun gear50is interlocked with the low reduction gear71, the low reduction carrier70and the first reduction carrier82may rotate together without reduction.

When the first reduction carrier82rotates, the first sun gear81spline-coupled to the first reduction carrier82may be rotated, and when the first sun gear81rotates, the planetary gear may rotate while the high reduction carrier60and the output shaft may be decelerated and rotated at the reduction ratio of N:1.

If the sun gear50is interlocked with the first planetary gear83by moving the input shaft20forward, the first planetary gear83may rotate while the first reduction carrier82and the first sun gear81may be primarily decelerated and rotated at the reduction ratio of N:1.

In addition, the planetary gear40may rotate by the rotation of the first sun gear81while the high reduction carrier60and the output shaft30may be secondarily decelerated and rotated at the reduction ratio of N:1.

As a result, by further providing the first reduction device80, the output shaft30may be greatly decelerated and rotated with respect to the input shaft20at a reduction ratio of N×N:1.

In the following, yet another embodiment of the present invention will be described with reference toFIG. 8.FIG. 8is a sectional view showing the structure of a planetary geared reducer with a dual reduction ratio according to yet another embodiment of the present invention.

Yet another embodiment of the present invention has a structure in which a second reduction device90is additionally mounted between the first reduction device80and the low reduction carrier70to implement a larger reduction ratio.

Preferably, the second reduction device90may have the same configuration as the first reduction device80.

In other words, the second reduction device90may include a second sun gear91, a second reduction carrier92, a second planetary gear93, a second housing94, and a second auxiliary carrier95.

The second sun gear91, the second reduction carrier92, the second planetary gear93, the second housing94, and the second auxiliary carrier95may have the same structure and shape as the first sun gear81, the first reduction carrier82, the first planetary gear83, the first housing84, and the first auxiliary carrier85, respectively.

In this case, the second sun gear91may be engaged with the first planetary gear83, and may have one end seated and supported by the first reduction carrier82and an opposite end provided with a spline so as to be spline-coupled to the second reduction carrier92.

An opposite end of the second sun gear91may be inserted into a center of the second reduction carrier92in one direction so as to be spline-coupled, and the end of the input shaft20may be inserted into the center of the second reduction carrier92in the opposite direction so as to be seated.

In this case, in order to rotatably support the end of the input shaft20, the bearing b may be interposed between the second reduction carrier92and the input shaft20.

Second planetary gears93may be arranged on the second reduction carrier92, and each of the second planetary gears93may be rotatably fixed by a second rotation pin96. Each of the second planetary gears93may be engaged with the sun gear50.

The second housing94may be provided on an outer side of the second planetary gear93, and the second housing94may be provided on an inner circumferential surface thereof with a second ring gear97engaged with the second planetary gears93.

In order to mount the second housing94, the input side housing11and the first housing84may be separated, and the second housing94may be assembled and fastened between the input side housing11and the first housing84.

In addition, one ends of the second rotation pins96may be fixed to the second reduction carrier92, and opposite ends of the second rotation pins96may be fixed to the low reduction carrier70, so that the second reduction carrier92and the low reduction carrier70may rotate together.

Further, a separate second auxiliary carrier95may be coupled to an opposite end of the first rotation pin96that has one end fixed to the first reduction carrier82so as to rotate together with the first reduction carrier82while preventing the first planetary gear83from being separated.

In this case, the output shaft30may be decelerated and rotated at the reduction ratio of N×N:1in the state in which the input shaft20is moved rearward, and the output shaft30may be decelerated and rotated at a reduction ratio of N×N×N:1 in the state in which the input shaft20is moved forward.

In this manner, a third reduction device, a fourth reduction device, and the like may be additionally mounted, and the reduction ratio may be gradually lowered each time the reduction device is additionally provided.

Although exemplary embodiments of the present invention have been described above with reference to the drawings, various applications and modifications may be made by those skilled in the art within the scope of the present invention based on the above contents. Therefore, the scope of the present invention should not be limited to the embodiments described above, but should be defined by the appended claims as well as equivalents thereof.