WO2021215899A1

WO2021215899A1 - Hybrid power transmission apparatus

Info

Publication number: WO2021215899A1
Application number: PCT/KR2021/005254
Authority: WO
Inventors: Kwang-Ho Jo
Original assignee: Park, Man-Jae
Priority date: 2020-04-24
Filing date: 2021-04-26
Publication date: 2021-10-28
Also published as: KR20210131643A

Abstract

Disclosed is a hybrid power transmission apparatus, in which an input gear section is rotated by a power applied from the outside based on a frame, a transmission gear section arranged to engage the input gear section is rotated by rotation of the input gear section, and an output section connected to an output gear section is rotated by rotation of the output gear section, after the output gear section disposed in engagement with the transmission gear section is rotated by rotation of the output gear section, wherein the output gear section includes a gear capable of rotation and revolution, the output section is connected to the output gear section to rotate by revolution of the gear included therein.

Description

HYBRID POWER TRANSMISSION APPARATUS

Various embodiments generally relate to a hybrid power transmission apparatus, and more particularly, to a hybrid power transmission apparatus with both a speed reducer function and a brake function in one consolidated system.

In general, a reduction gear or a speed reducer may be referred to as a mechanical device to reduce the rotational speed (RPM) of an electric motor to increase its torque, by means of a combination of gears with different gear ratios.

Such a reduction gear or a speed reducer (hereinafter, generally referred to as "reducer") is also used in lifting or lowering a heavy load, to which a brake function may be equipped or a worm gear reducer or the like may be used allowing no reverse rotation.

For example, a brake may be arranged on one side of a gearbox in a hoist, a lever block, a chain block, and so on, and a worm reducer with no reverse rotation allowed, may be dominantly used for an elevator and an escalator. A Korean Patent Publication No. 2003-0056791 discloses an example of such a worm gear reducer, selected for fall prevention during its operation.

However, there is often a problem that such a reducer with a brake not only may entail an increase in its product cost but also incurs additional costs for maintenance and management as the brake has to be maintained and managed in an optimal state at all times.

Furthermore, a worm gear reducer with a larger frictional force can increase its reduction ratio, but since it is configured to transmit power by friction, the transmission efficiency is relatively low and heating is easily generated. Therefore, it frequently results in short life expectancy of the gear and large energy loss.

Various embodiments aim to provide a hybrid power transmission apparatus capable of implementing a function of a speed reducer, as well as automatically preventing the rotation of an output section even if a forced external force acts on the output section after the power for implementing the function of the reducer is cut off.

According to an aspect, there is provided a hybrid power transmission apparatus, in which an input gear section is rotated by power applied from the outside with respect to a frame, a transmission gear section arranged to engage the input gear section is rotated by rotation of the input gear section, an output gear section disposed in engagement with the transmission gear section is rotated by rotation of the transmission gear section, and in turn, an output section coupled with the output gear section is rotated by rotation of the output gear section;

wherein the output gear section may include at least one gear capable of rotation and revolution, and the output section may be connected to the output gear section to rotate by revolution of the gear included therein;

the hybrid power transmission apparatus further comprising at least one sun gear with a first external gear and a second external gear respectively formed on one side and the other side of its circumferential surface, at least one ring gear disposed outside the sun gear, with a first internal gear and a second internal gear respectively formed on one side and the other side of its inner circumferential surface, a first intermediate gear disposed in engagement with the first external gear and the first internal gear, being rotatable about a fixed axis, and a second intermediate gear disposed in engagement with the second external gear and the second internal gear, being capable of rotation and revolution; and

wherein the first external gear and the second external gear are disposed coaxially, the input gear section and the output gear section are of the first internal gear and the second internal gear, respectively, and the frame is positioned in between the first intermediate gear and the second intermediate gear, fixing a rotation axis of the first intermediate gear.

The ring gear of the hybrid power transmission apparatus according to the present disclosure may be configured so that the sun gear is inserted to provide a rotation axis of the sun gear.

The hybrid power transmission apparatus according to the present disclosure may be configured to meet a predetermined first condition to implement a function of speed reduction, wherein the predetermined first condition may be defined by the following conditional expression:

B/A ≠D/C

wherein ' A' is a vertical distance from the central axis AX to a gearing point of the first internal gear and the first intermediate gear, ' B' is a vertical distance from the central axis AX to a gearing point of the first intermediate gear and the first external gear, ' C' is a vertical distance from the central axis AX to a gearing point of the second internal gear and the second intermediate gear, and ' D' is a vertical distance from the central axis AX to a gearing point of the second intermediate gear and the second external gear.

The hybrid power transmission apparatus according to the present invention may be configured to meet a predetermined second condition, so that when a forced external force acts on the output section after the power is cut off, the rotation of the output section by the forced external force can be prevented, wherein the predetermined second condition may be defined by the following conditional expression:

(B/A) + α = D/C

wherein ' A' is a vertical distance from the central axis AX to a gearing point of the first internal gear and the first intermediate gear, ' B' is a vertical distance from the central axis AX to a gearing point of the first intermediate gear and the first external gear, ' C' is a vertical distance from the central axis AX to a gearing point of the second internal gear and the second intermediate gear, ' D' is a vertical distance from the central axis AX to a gearing point of the second intermediate gear and the second external gear, and ' α' is a value when the magnitude and direction of the force acting on a gearing point of the first intermediate gear and the first external gear is the same as the magnitude and direction of the force acting on a gearing point of the first intermediate gear and the first internal gear.

The hybrid power transmission apparatus according to the present disclosure can implement the function of a speed reducer as well as automatically prevent the rotation of the output section even though any forced external force acts on the output section after the power for implementing the function of the reducer is cut off.

Therefore, in case where the hybrid power transmission apparatus according to the present disclosure is applied to an elevator, an escalator, a hoist, and so on, any additional device such as e.g., a brake is not required, thereby ensuring the best safety at a low cost.

The above and other objects, features, and advantages of the present disclosure will be more clearly understood from the following detailed description, taken in conjunction with the accompanying drawing, wherein FIG. 1 illustrates a schematic sectional view for describing a hybrid power transmission apparatus according to the present disclosure.

In the following description of examples or embodiments of the present disclosure, reference will be made to the accompanying drawings in which it is shown by way of illustration specific examples or embodiments that can be implemented, and in which the same reference numerals and signs can be used to designate the same or like components even when they are shown in different accompanying drawings from one another. Further, in the following description of examples or embodiments of the present disclosure, detailed descriptions of well-known functions and components incorporated herein will be omitted when it is determined that the description may make the subject matter in some embodiments of the present disclosure rather unclear. The terms such as "including", "comprising", "having", and "formed of" used herein are generally intended to allow other components to be added unless the terms are used with the term "only". As used herein, singular forms are intended to include plural forms unless the context clearly indicates otherwise.

Further, components having the same function within the scope of the same idea set forth in the drawings of a respective embodiment will be described using the same reference numerals.

A hybrid power transmission apparatus according to the present disclosure (hereinafter, referred to as "power transmission apparatus") is a type of gear reducer that uses a plurality of gears to reduce the power of an electric motor such as e.g., a prime mover by a predetermined reduction ratio as well as amplify its torque.

More specifically, the power transmission apparatus is configured so that an input gear section is rotated by power applied from the outside, a transmission gear section arranged to engage the input gear section is rotated by rotation of the input gear section, an output gear section disposed in engagement with the transmission gear section is rotated by rotation of the transmission gear section, and in turn, an output section coupled with the output gear section is rotated by rotation of the output gear section.

The input gear section, the transmission gear section, and the output gear section may be implemented by various types of gears or combinations thereof, respectively, for example, with one or more of spur gears, internal gears, helical gears, bevel gears, planetary gears or the like.

The output gear section may include at least one gear capable of rotation and revolution, and the output section may be connected to the output gear section as a carrier to be rotated by the revolution of the gear included in the output gear section.

The power transmission apparatus may be adapted to satisfy a predetermined first condition for implementing a speed reduction function, and then the predetermined first condition will be described later.

Hereinafter, description will be made to a preferred embodiment of a combination of gears capable of implementing the input gear section, the transmission gear section, and the output gear section, only by way of an example only, but the present invention is not limited to the embodiments described below.

In the meantime, the power transmission apparatus may be configured to satisfy a predetermined second condition such that when a forced external force acts on the output section after the power is cut off, the rotation of the output section by the forced external force is prevented, and the predetermined second condition will be described later.

In case where the power transmission apparatus according to the present disclosure that satisfies the predetermined first condition and the predetermined second condition is used in e.g., an elevator, it makes it possible to prevent rotation of the output section owing to heavy load of the elevator itself, without a separate brake equipped therein.

FIG. 1 shows a schematic cross-sectional view for explaining the configuration of a hybrid power transmission apparatus according to the present disclosure.

Referring now to FIG. 1, the hybrid power transmission apparatus according to the present disclosure may include at least one sun gear 110, at least one ring gear 120, at least one first intermediate gear 130, and at least one second intermediate gear 140.

The sun gear 110 may have a first external gear 112 and a second external gear 114 respectively formed on one side and the other side of the outer circumferential surface.

The first external gear 112 and the second external gear 114 may be disposed coaxially and formed of a single member.

However, the first external gear 112 and the second external gear 114 need not necessarily be formed as such a single member, and may be coupled on a coaxial cylinder to rotate in conjunction with the coaxial cylinder.

The sun gear 110 may be inserted into a central axis 126 of the ring gear 120, and the ring gear 120 may provide a rotation axis of the sun gear 110.

The first external gear 112 and the second external gear 114 may be implemented as either a spur gear or a helical gear. Otherwise, the first external gear 112 may be implemented as a spur gear, and the second external gear 114 may be implemented as a helical gear. Naturally, the opposite arrangement would be also possible.

The ring gear 120 may be disposed outside the sun gear 110, and a first internal gear 122 and a second internal gear 124 may be formed on one side and the other side of the inner circumferential surface, respectively.

The first internal gear 122 and the second internal gear 124 may be implemented as either a spur gear or a helical gear, but the first external gear 112 and the second external gear 114 may be preferably implemented with a same type of gears, respectively.

The first intermediate gear 130 may be disposed so as to mesh with the first external gear 112 and the first internal gear 122, and may be rotatably fixed to a frame 300.

Since the first intermediate gear 130 is rotatably fixed to the frame 300, it is to be appreciated that that only its rotation is possible, but its revolution is not possible.

The first intermediate gear 130 may be implemented as a gear same as to the first external gear 112 and the first internal gear 122, and the number of the first intermediate gears 130 is not limited.

The second intermediate gear 140 may be disposed so as to mesh with the second external gear 114 and the second internal gear 124, and it may be a kind of planetary gear capable of rotation and revolution, of which rotation axis and revolution axis are arranged parallel to each other.

Here, as seen in FIG. 1, the power transmission apparatus 100 according to the present disclosure shows that the sun gear 110 with the first external gear 112 and the second external gear 114 formed thereon, the ring gear 120 with the first internal gear 122 and the second internal gear 124 formed thereon, and the first and second intermediate gears 130 and 140 can configure an input gear section, a transmission gear section, and an output gear section as described above. Hereinafter, the arrangement of gears will be described in detail.

The input gear section and the output gear section may correspond to the first internal gear 122 and the second intermediate gear 140, respectively.

The first internal gear 122 may be connected to a rotation shaft of a motor 200 that generates a rotational force like e.g., a prime mover, so as to rotate based on the rotation of the rotation shaft of the motor 200.

Of course, it is to be appreciated that the interlocking of the first internal gear 122 with the rotation of the rotation shaft of the motor 200 may be implemented by various methods such as, e.g., engagement of gearing.

The second intermediate gear 140 may correspond to the output gear section and the number of these gears may change. However, a plurality of, for instance, two or more, second intermediate gears 140 may be preferably formed for connection with a carrier 150 which is the output section 150.

Gears other than the first internal gear 122 and the second intermediate gear 140, that is, the first external gear 112, the second external gear 114, the first intermediate gear 130 and the second internal gear 124 may correspond to the transmission gear section.

In the meantime, the frame 300 may be disposed in between the first intermediate gear 130 and the second intermediate gear 140, fixing the rotation axis of the first intermediate gear 130 as described above.

Then, explaining the operation of the gears as an example, first of all, once the ring gear 120 rotates in a clockwise direction (X1) by the power of the motor 200, the first intermediate gear 130 engaged with the first internal gear 122 of the ring gear 120 is caused to rotate in a counterclockwise direction.

When the first intermediate gear 130 rotates in a counterclockwise direction, the first external gear 112 engaged therewith is caused to rotate in a clockwise direction (X1), which in turn allows the sun gear 110 to rotate in a clockwise direction (X1).

Then, once the sun gear 110 and the ring gear 120 rotates in the clockwise direction (X1), the second intermediate gear 140 engaged therewith rotates in the clockwise direction (X1), and at the same time, the second intermediate gear 140 itself is caused to revolve in the clockwise direction (X1).

Here, the second intermediate gear 140 simultaneously involves the rotation and the revolution in the clockwise direction by rotation of the second external gear 114 and the second internal gear 124, and thus, the revolution causes the output section 150 connected to the second intermediate gear 140, that is, the carrier 150 to rotate in a clockwise direction as well.

Of course, it should be obviously understood that when the rotation shaft is rotated counterclockwise by the power of the motor 200, the rotation directions of the gears will all be reversed.

An elevator wire may be wound on the carrier 150, for example, and the elevator may move up and down by the rotation of the carrier 150.

Further, the carrier 150 may be used for a joint of a robot and the like, to implement an effect of bending the joint.

The rotation speed of the carrier 150 may be different from the rotation speed of the rotation shaft by the power of the motor. Then, if the rotation speed of the carrier 150 goes smaller than the speed rotation of the rotation shaft by the power of the motor 200, the power transmission apparatus 100 according to the present disclosure can implement the function of such a speed reducer.

Here, it should be noted that the reduction ratio may vary depending on the characteristics of the first external gear 112, the second external gear 114, the first internal gear 122, the second internal gear 124, the first intermediate gear 130, and the second intermediate gear 140, for example, on their diameters and so on, and those skilled in the art could conveniently set the diameters of the gears based on a desired reduction ratio.

In the following, the relationship between the rotation speed of the input gear section and the rotation speed of the output gear section will be described to prove that the deceleration function is efficiently implemented.

First of all, the definition of the reference symbols set forth in the drawing of FIG. 1 is made prior to entering its detailed description, wherein ' A' is a vertical distance from the central axis AX to a gearing point of the first internal gear 122 and the first intermediate gear 130, ' B' is a vertical distance from the central axis AX to a gearing point of the first intermediate gear 130 and the first external gear 112, ' C' is a vertical distance from the central axis AX to a gearing point of the second internal gear 124 and the second intermediate gear 140, and ' D' is a vertical distance from the central axis AX to a gearing point of the second intermediate gear 140 and the second external gear 114.

Thus, looking first at the relationship between the number of revolutions (Win) of the ring gear 120, which is an input gear section, by the power of the motor 200, and the number of rotations (W sun-gear) of the sun gear 110, the following formula 1 may be derived:

W sun-gear = - (A/B) Win ...... Formula 1

wherein the rotation direction of the sun gear 110 and the rotation direction of the ring gear 120 are caused to be opposite by the first intermediate gear 130.

Then, looking at the relationship between the number of rotations (W sun-gear) of the sun gear 110 and the number of rotations (Wout1) of the first intermediate gear 130 depending only on the rotation of the sun gear 110, the following formula 2 may be derived:

Wout1 = {C/(C+D)} W sun-gear ......Formula 2

wherein the ring gear 120 is assumed to be in a fixed state.

Then, looking at the relationship between the number of rotations (Win) of the ring gear 120 and the number of rotations (Wout2) of the first intermediate gear 130 depending only on the rotation of the ring gear 120, the following formula 3 may be derived:

Wout2 = {D/(C+D)} Win ......Formula 3

wherein the sun gear 110 is assumed to be in a fixed state.

Finally, the number of rotations (Wout) of the final first intermediate gear 130 may be derived using the following formula 4:

Wout = Wout1 + Wout2

= {1/(C+D)}*{(BD-AC/B) Win ......Formula 4

As understood from the above relationship of formulas, changing the values of A, B, C and D enables various reduction ratios to be obtained.

In the meantime, as seen from the above formula 4, a predetermined first condition should be satisfied in order for the power transmission apparatus 100 according to the present disclosure to implement the deceleration function, wherein the predetermined first condition may be of the following conditional expression 1:

B/A ≠ D/C ......Conditional Expression 1

If the condition of the above expression 1 is met, then various reduction ratios can be obtained as desired.

In the meantime, the power transmission apparatus 100 according to the present disclosure does not cause the carrier 150 to rotate if a predetermined second condition in the following conditional expression 2 is satisfied, even when any forced external force is applied onto the carrier 150 after the power of the motor is cut off.

(B/A) + α = D/C ......Conditional Expression 2

wherein ' α' is a value when the magnitude and direction of the force acting on the gearing point of the first intermediate gear 130 and the first external gear 112 is the same as the magnitude and direction of the force acting on the gearing point of the first intermediate gear 130 and the first internal gear 122.

The value ' α' may be derived using an empirical equation, and may vary depending on the values of A, B, C, and D, and the rigidity of a respective gear.

When an external force to rotate the carrier 150 clockwise is applied to the carrier 150 after the power of the motor is cut off, and if the above conditional expression 2 is satisfied, the second intermediate gear 140 connected to the carrier 150 then transmits the same rotational force to the second external gear 114 of the sun gear 110 and the second internal gear 124 of the ring gear 120. Consequently, the same power is caused to be transmitted to the first external gear 112 of the sun gear 110 and the first internal gear 122 of the ring gear 120.

It eventually causes the same size of the rotational force in the clockwise direction to be transmitted to the gearing point of the first external gear 112 and the first intermediate gear 130, and the gearing point of the first internal gear 122 and the first intermediate gear 130, so that the rotation of all gears including the first intermediate gear 130 becomes impossible.

At the end therefore, despite the external force acting on the carrier 150, the carrier 150 may not be rotatable, and in case where the wire of the elevator is wound on the carrier 150, it will be possible to prevent in advance the elevator from being lowered by its own heavy weight when the power is suddenly cut off even without a separate brake device.

Thus, according to the present disclosure, a person skilled in the art can set the diameters of the first external gear 112, the second external gear 114, the first internal gear 122, the second internal gear, the first intermediate gear 130, and the second intermediate gear 140, according to the above conditional expression 2 based on the desired reduction ratio, so that they satisfy the conditional expression 2, and the power transmission apparatus 100 can provide a function of preventing forced rotation when the power of the motor is cut off, as well as a function as a speed reducer.

Meanwhile, the input gear section may be the first intermediate gear 130 or the sun gear 110 in addition to the ring gear 120, and even in case where the input gear section is either the first intermediate gear 130 or the sun gear 110, the carrier 150 is not caused to rotate despite the external force acting on the carrier 150 after the power of the motor 200 is cut off, if both the conditional expression 1 and the conditional expression 2 are satisfied.

The above description has been presented to enable any person skilled in the art to make and use the technical idea of the present disclosure, and has been provided in the context of a particular application and its requirements. Various modifications, additions and substitutions to the described embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the present disclosure. The above description and the accompanying drawings provide an example of the technical idea of the present disclosure for illustrative purposes only. That is, the disclosed embodiments are intended to illustrate the scope of the technical idea of the present disclosure. Thus, the scope of the present disclosure is not limited to the embodiments shown, but is to be accorded the widest scope consistent with the claims. The scope of protection of the present disclosure should be construed based on the following claims, and all technical ideas within the scope of equivalents thereof should be construed as being included within the scope of the present disclosure.

Claims

A hybrid power transmission apparatus, in which an input gear section is rotated by a power applied from the outside with respect to a frame, a transmission gear section arranged to engage the input gear section is rotated by rotation of the input gear section, an output gear section disposed in engagement with the transmission gear section is rotated by rotation of the transmission gear section, and in turn, an output section coupled with the output gear section is rotated by rotation of the output gear section, wherein:

the output gear section includes a gear capable of rotation and revolution, and

the output section is connected to the output gear section to rotate by revolution of the gear included therein;

the hybrid power transmission apparatus comprising:

at least one sun gear with a first external gear and a second external gear respectively formed on one side and the other side of its circumferential surface;

at least one ring gear disposed outside the sun gear, with a first internal gear and a second internal gear respectively formed on one side and the other side of its inner circumferential surface;

a first intermediate gear disposed in engagement with the first external gear and the first internal gear, being rotatable about a fixed axis; and

a second intermediate gear disposed in engagement with the second external gear and the second internal gear, being capable of rotation and revolution;

wherein the first external gear and the second external gear are disposed coaxially,

the input gear section and the output gear section are formed of the first internal gear and the second internal gear, respectively;

the frame is positioned in between the first intermediate gear and the second intermediate gear, thereby fixing a rotation axis of the first intermediate gear.
The hybrid power transmission apparatus according to claim 1, wherein the ring gear is configured so that the sun gear is inserted thereto to provide a rotation axis of the sun gear.
The hybrid power transmission apparatus according to claim 1, wherein the hybrid power transmission apparatus is configured to meet a predetermined first condition to implement a function of speed reduction, and the predetermined first condition is defined by the following conditional expression:

B/A ≠ D/C

wherein ' A' is a vertical distance from the central axis AX to a gearing point of the first internal gear and the first intermediate gear, ' B' is a vertical distance from the central axis AX to a gearing point of the first intermediate gear and the first external gear, ' C' is a vertical distance from the central axis AX to a gearing point of the second internal gear and the second intermediate gear, and ' D' is a vertical distance from the central axis AX to a gearing point of the second intermediate gear and the second external gear.
The hybrid power transmission apparatus according to claim 1, wherein the hybrid power transmission apparatus is configured to meet a predetermined second condition, so that when a forced external force acts on the output section after the power is cut off, the rotation of the output section by the forced external force is prevented, and the predetermined second condition is defined by the following conditional expression:

(B/A) + α = D/C

wherein ' A' is a vertical distance from the central axis AX to a gearing point of the first internal gear and the first intermediate gear, ' B' is a vertical distance from the central axis AX to a gearing point of the first intermediate gear and the first external gear, ' C' is a vertical distance from the central axis AX to a gearing point of the second internal gear and the second intermediate gear, ' D' is a vertical distance from the central axis AX to a gearing point of the second intermediate gear and the second external gear, and ' α' is a value when the magnitude and direction of the force acting on a gearing point of the first intermediate gear and the first external gear is the same as the magnitude and direction of the force acting on a gearing point of the first intermediate gear and the first internal gear.