Patent Description:
Refrigerants are essential for air conditioners, which are one of the air conditioning systems, and the first to third generation refrigerants that have been used previously have very high ozone layer depletion potential (ODP) and/or global warming potential (GWP).

Therefore, in recent years, fourth-generation refrigerants with low ozone depletion potential and/or global warming potential have been developed, and newly developed fourth-generation refrigerants, for example, hydrogen fluoroolefin (HFO)-based refrigerants, are more expensive than conventional refrigerants and are flammable, resulting in a risk of fire and/or explosion.

Therefore, the air conditioning system is provided with a ball valve for blocking refrigerant leakage.

The ball valve provided in an air conditioning system to block refrigerant leakage includes a ball in which a flow path is formed, a pipe into which the ball is inserted, a tap part provided in the pipe, and a stem installed in the tap part.

The ball valve of this configuration can open and close the refrigerant by rotating the stem, and the air conditioning system used for industrial purposes is provided with a valve actuator that is operated by an electrical signal input from the outside to block and operate the ball valve.

The valve actuator may not have a separate manual rotation mode or may have a manual rotation mode by applying a motor capable of reverse rotation.

One example of a valve actuator having a manual rotation mode is disclosed in US Publication No. <CIT>.

The valve actuator of this document has a clutch unit used in the manual rotation mode installed on the output shaft of the gear assembly.

That is, in the valve actuator of the above document, the gear train is disengaged when the output shaft (valve rotation shaft) is pressed in the axial direction, and after rotating the valve in this state, if the pressing of the output shaft is disengaged, the position of the output shaft returns to its original position by the return spring.

Therefore, the valve actuator of the above document has a problem in that sealing performance is deteriorated because the output shaft moves in two directions, i.e., a rotational direction and an axial direction (a vertical direction), and there is a problem in that the size of the product increases because the output shaft must move in the axial direction in the manual rotation mode.

In addition, a strong and large return spring is required to return the output shaft to its original position, and since the engagement between gear teeth is directly disengaged in the manual rotation mode, there is a problem that the gear teeth are adversely affected.

US Publication No. <CIT>. <CIT> relates to a valve actuator for rotating a valve shaft of a valve such as a ball valve through a reduction mechanism using an electric motor as a power source. <CIT> discloses a further example of a valve actuator.

An object of the present disclosure is to provide a valve actuator capable of solving at least one of the above problems.

Another object of the present disclosure is to provide a valve actuator having a gear assembly having a simple structure.

Still another object of the present disclosure is to provide a valve actuator capable of implementing a manual rotation mode even with a small force.

Still another object of the present disclosure is to provide a valve actuator capable of minimizing adverse effects on gear teeth in a manual rotation mode.

Still another object of the present disclosure is to provide a valve actuator capable of returning a clutch shaft to its original position even when a return spring fails to operate.

Still another object of the present disclosure is to provide a valve actuator with improved sealing performance.

Still another object of the present disclosure is to provide a valve actuator having a reduced size.

Objects of the present disclosure are not limited to the above-mentioned objects, and other objects and advantages of the present disclosure not mentioned above can be understood by the following description and more clearly will be understood by the embodiments of the present disclosure.

It will also be readily seen that the objects and advantages of the present disclosure may be realized by the means and combinations indicated in the claims.

In a valve actuator according to an embodiment of the present disclosure, a gear assembly transmitting a driving force of a motor to a ball valve includes an input gear coupled to a rotation shaft of the motor and rotating together with the rotation shaft; an output gear positioned apart from the input gear in a horizontal direction, coupled to a stem of the ball valve, and transmitting a rotational force of the input gear to the stem; and a power transmission gear transmitting the rotational force of the input gear to the output gear.

In addition, the power transmission gear includes a first gear set positioned between the input gear and the output gear, wherein the first gear set includes a clutch shaft installed in the housing so as to be movable in a vertical direction; and a first gear and a second gear coupled to the clutch shaft and disengaged from each other or coupled to each other by vertical movement of the clutch shaft.

In addition, the power transmission gear may further include a second gear set disposed adjacent to the first gear set in the horizontal direction, and wherein the second gear set may include a third gear coupled to the first gear; and a fourth gear positioned above the third gear, integrally rotating with the third gear, and coupled with the output gear.

According to this configuration, since the middle shaft (shaft of power transmission gear) of the gear train, not the output shaft to which the output gear is coupled, is formed as the clutch shaft, the clutch shaft may be operated with a smaller force compared to the case where the output shaft is used as the clutch shaft.

Therefore, a smaller spring than a conventional return spring for returning the output shaft to its original position may be used as the return spring.

In addition, since it is possible to couple or release between the first and second gears according to the vertical movement of the clutch shaft, when the clutch shaft is operated, coupling between gears is disengaged, not disengagement of coupling between gear teeth.

Therefore, when the clutch shaft moves in the vertical direction, the influence on the teeth of the input gear, the output gear, and the power transmission gear may be minimized.

In addition, since the power transmission gear is composed of two gear sets, it is possible to simplify the configuration of the gear assembly.

A coupling part for coupling the first gear to the second gear is protruded from a lower surface of the first gear coupled to the input gear, and a coupling part insertion groove into which the coupling part of the first gear is inserted is formed on an upper surface of the second gear.

The coupling part and the coupling part insertion groove may be formed in shapes corresponding to each other, and the planar shape may be formed into an elliptical, polygonal, or splined shape.

According to this configuration, the height or thickness of the first gear set in the vertical direction may be reduced.

Accordingly, since the size of the space formed by a middle plate and a lower case can be reduced, the size of the valve actuator can be reduced.

A push-up part is formed on the clutch shaft to push the first gear upward in
contact with the coupling part of the first gear, and the push-up part is positioned in a push-up part insertion groove formed on a lower surface of the coupling part of the first gear.

Accordingly, since the size of the space formed by the middle plate and the lower case can be reduced, the size of the valve actuator may be further reduced.

The housing may include a lower case; an upper case coupled to the lower case; and a middle plate positioned in the inner space formed by the lower case and the upper case, wherein the motor and the gear assembly may be positioned in an inner space formed by the middle plate and the lower case.

According to this configuration, since the length of the axis coupled to the rotational shaft of the motor and the gears of the gear assembly may be shortened, and the size of the space formed by the middle plate and the upper case may be greatly reduced, the size of the valve actuator may be further reduced.

The first gear may be pressed toward the second gear by a return spring disposed between the first gear and the middle plate.

According to this configuration, the first gear and the second gear are maintained in a couping state before the valve actuator operates.

When the clutch shaft is pressed upward, the first gear is pushed up by the push-up part while the return spring is pressed, and thus the coupling between the first gear and the second gear is disengaged.

After that, when the pressing of the clutch shaft is disengaged, the first gear is pressed downward by the return spring, and when the output shaft of the output gear rotates and the coupling part of the first gear is inserted into the coupling part insertion groove of the second gear, the first gear and the second gear are coupled again.

A snap ring may be installed on the clutch shaft between the return spring and an upper surface of the first gear.

According to this configuration, when the first gear does not move downward due to a malfunction of the return spring despite disengaging the pressing of the clutch shaft, the first gear and the second gear may be coupled by pulling the clutch shaft downward.

A third seal ring may be disposed on the clutch shaft below the second gear, and a guide groove may be formed in the lower case where the clutch shaft is coupled and allow the third seal ring to move in the vertical direction together with the clutch shaft when the clutch shaft moves in the vertical direction.

According to this configuration, a movement distance of the clutch shaft in an upward direction may be set by a gap between the third seal ring and the second gear.

In addition, the seal ring and/or the lower case may support the second gear in a state in which the coupling between the gears of the first gear and the second gear is disengaged.

The power transmission gear may further include a second gear set disposed adjacent to the first gear set in the horizontal direction, and the second gear set may include a third gear coupled to the first gear; and a fourth gear positioned above the third gear, integrally rotating with the third gear, and coupled with the output gear.

The third gear and the fourth gear may be integrally formed or may be manufactured separately and coupled to each other similarly to the first and second gears.

According to this configuration, it is possible to further simplify the configuration of the gear assembly including the power transmission gear.

When the clutch shaft moves upward, an upward movement of the second gear may be inhibited by the motor and the third gear.

According to this configuration, since the inner space formed by the lower case and the middle plate can be reduced, the size of the valve actuator can be further reduced.

According to the valve actuator according to the embodiment of the present disclosure, it is possible to solve the problem of the valve assembly applicable only to specially manufactured valves having a flange shape and the problem of the valve assembly assembled to the valve by the principle of fastening the bottle cap.

In addition, the valve actuator according to the embodiment of the present disclosure can be additionally mounted and used in standard ball valves of various sizes.

In addition, the valve actuator according to the embodiment of the present disclosure can maintain a good assembly state with the ball valve.

In addition, the valve actuator according to the embodiment of the present disclosure can be smoothly engaged with the ball valve even if the starting point of the thread provided in the tap part of the ball valve is not constant.

In addition, the valve actuator according to the embodiment of the present disclosure can maintain good airtightness even in an environment with a large temperature difference or an inundation environment.

In addition, the valve actuator according to the embodiment of the present disclosure can have airtight performance of completely waterproof and dustproof (IP67).

In addition to the above effects, specific effects of the present disclosure will be described together while explaining specific details for implementing the description below.

Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings so that those skilled in the art can easily carry out the embodiments of the present disclosure. The present disclosure may be implemented in many different forms and is not limited to the embodiments described herein.

In order to clearly describe the present disclosure, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification. In addition, some embodiments of the present disclosure will be described in detail with reference to exemplary drawings.

In adding reference numerals to components of each drawing, the same components may have the same numerals as much as possible even though they are displayed on different drawings. In addition, in describing the present disclosure, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the present disclosure, the detailed description may be omitted.

In describing the components of the present disclosure, when a component is described as "connected", "coupled" or "contacted" to another component, the component may be directly connected or contacted to the other component, but it should be understood that other components may be "interposed" between each component, or each component may be "connected", "coupled" or "contacted" via other components.

<FIG> is a view showing a state in which a valve actuator and a ball valve are assembled according to an embodiment of the present disclosure, <FIG> is an exploded perspective view of main parts of <FIG>, as viewed from above, and <FIG> is an exploded perspective view of main parts of <FIG>, as viewed from the bottom.

<FIG> is a cross-sectional view of a flange, <FIG> is a perspective view of a gear assembly in which a first gear and a second gear coupled to a clutch shaft are disassembled, as viewed from above, and <FIG> is a perspective view of a gear assembly in which a first gear and a second gear coupled to a clutch shaft are disassembled, as viewed from above.

<FIG> is a cross-sectional view showing a state in which an output shaft of a gear assembly is assembled to a housing and a flange, and <FIG> is a cross-sectional view showing a state in which a clutch shaft, first gear, and second gear of a gear assembly are assembled to a housing.

<FIG> is a cross-sectional view showing a state in which a clutch shaft of a gear assembly is pressed, and <FIG> is a cross-sectional view showing a state in which an adhesive is applied to a power line passage hole of a housing.

A ball valve <NUM> provided in the air conditioning system to block refrigerant leakage includes a ball in which a flow path is formed, a pipe <NUM> into which the ball is inserted, a tap part <NUM> provided in the pipe <NUM>, and a stem <NUM> installed on the tap part <NUM>.

In order to install a valve actuator on the tap part <NUM> of the standardized ball valve <NUM> of this configuration, the valve actuator of the present disclosure includes a flange <NUM> screwed to the tap part <NUM> of the ball valve <NUM> but coupled to a housing <NUM> of the valve actuator by a fastening member such as a screw or bolt.

In this way, according to the structure in which the flange <NUM> is provided separately from the ball valve <NUM> and the housing <NUM> and coupled to the ball valve <NUM> and the housing <NUM> by a separate fastening member or a separate fastening method, it is possible to additionally install the valve actuator to the ball valves <NUM> of various standards already installed in the field.

The flange <NUM> has a tap part insertion hole <NUM> in which a tap part <NUM> screwed with the tap part <NUM> of ball valve is formed on an inner surface.

In addition, a stem insertion hole <NUM> communicating with the tap part insertion hole <NUM> and into which the stem <NUM> of the ball valve <NUM> is inserted, and a plurality of long holes <NUM> positioned at a certain distance from the center of the tap part insertion hole <NUM> and formed long in the circumferential direction are further provided.

In addition, the flange <NUM> has a chamfer <NUM> formed on the inner surface of the tap part insertion hole <NUM>.

In addition, a chamfer <NUM> having a shape corresponding to the chamfer <NUM> of the flange <NUM> is formed at the top of the tap part <NUM> of the ball valve <NUM>.

Thus, in a state where the flange <NUM> is screwed to the tap part <NUM> of the ball valve <NUM>, the chamfer <NUM> of the flange <NUM> is in contact with the chamfer <NUM> formed at the upper end of the tap part <NUM> of the ball valve <NUM>.

According to this configuration, a supporting reaction force is formed by the chamfers <NUM> and <NUM> in contact with each other in a state where the flange <NUM> is screwed to the tap part <NUM> of the ball valve <NUM>.

Therefore, even if the valve turning torque is greater than the screw fastening force between the tap part <NUM> of the flange <NUM> and the tap part <NUM> of the ball valve <NUM>, loosening between the tap part <NUM> of the flange <NUM> and the tap part <NUM> of the ball valve <NUM> is suppressed, and the assembly state between the tap part <NUM> of the flange <NUM> and the tap part <NUM> of the ball valve <NUM> is maintained well.

In addition, when screwing the tap part <NUM> of the flange <NUM> to the tap part <NUM> of the ball valve <NUM>, even if the starting point of the thread formed in the tap part <NUM> of the ball valve <NUM> is not constant, it is possible to smoothly screw the tap part <NUM> of the flange <NUM> to the tap part <NUM> of the ball valve <NUM>.

The flange <NUM> further includes a ring insertion groove <NUM> formed on the upper surface and in which a second seal ring R2 is disposed.

According to this configuration, it is possible to prevent moisture from entering the inside of the housing <NUM> through a minute gap formed between the flange <NUM> and a flange coupling part <NUM>.

The housing <NUM> provides a space in which a motor <NUM> and a gear assembly <NUM> provided in the valve actuator are installed.

The housing <NUM> includes a lower case <NUM>, an upper case <NUM> coupled to the lower case <NUM>, an middle plate <NUM> positioned in an inner space formed by the lower case <NUM> and the upper case <NUM>, and a flange coupling part <NUM> provided on the lower case <NUM> and coupled to the flange <NUM>.

In this embodiment, the motor <NUM> and the gear assembly <NUM> will be described as an example of being disposed in a space formed by the middle plate <NUM> and the lower case <NUM>.

However, the motor <NUM> may be disposed in a space formed by the middle plate <NUM> and the upper case <NUM>, in this case, the arrangement of the plurality of gears provided in the gear assembly <NUM> may be different from the arrangement structure described in the present embodiment.

However, even if the arrangement position of the motor <NUM> and the gear assembly <NUM> and the arrangement structure of the gear assembly <NUM> are partially different from those of the present embodiment, it falls within the scope of the present disclosure if it includes the features of the present disclosure.

The flange coupling part <NUM> of the housing <NUM> has a plurality of circular grooves 34a into which a plurality of fastening members <NUM> passing through the plurality of long holes <NUM> are fastened, respectively.

Each of the plurality of long holes <NUM> communicates with at least one of the plurality of circular grooves 34a.

At this time, the number of the plurality of circular grooves 34a may be formed to be twice or more than the number of the plurality of long holes <NUM>.

In this way, when the number of the plurality of circular grooves 34a is formed to be twice or more than the number of the plurality of long holes <NUM>, when screwing the flange <NUM> to the tap part <NUM> of the ball valve <NUM>, even if the starting point of the thread formed in the tap part <NUM> of the ball valve <NUM> is not constant, the flange <NUM> may be smoothly screwed into the tap part <NUM> of the ball valve <NUM>.

However, it is also possible to form the number of the plurality of circular grooves 34a to be the same as the number of the plurality of long holes <NUM>.

In addition, it is also possible to form the number of the plurality of circular grooves 34a to be <NUM> times or more and less than <NUM> times the number of the plurality of long holes <NUM>.

According to this configuration, after screwing the tap part <NUM> of the flange <NUM> to the tap part <NUM> of the ball valve <NUM>, when coupling the housing <NUM> to the flange <NUM> using the fastening member <NUM>, even if the rotational phase of the flange <NUM> is different, the flange <NUM> can be smoothly fastened to the flange coupling part <NUM> of the housing <NUM>.

Here, the rotational phase of the flange <NUM> may vary depending on the starting point of a thread provided in the tap part of the ball valve.

A distance D1 between the two adjacent long holes <NUM> is smaller than a distance D2 between the two adjacent circular grooves 34a.

In addition, a bridge <NUM> is positioned between the two adjacent long holes <NUM>, and the width of the bridge <NUM>, that is, the distance D1 between the two adjacent long holes <NUM> is smaller than the length L of the long holes <NUM>.

Thus, the strength of the flange <NUM> is properly maintained due to the bridge <NUM>.

The housing <NUM> may have a power line passage hole <NUM> through which an external power line <NUM> for supplying power to the motor <NUM> passes, and an adhesive <NUM> may be applied to the power line passage hole <NUM> in a state where the external power line <NUM> passes through.

The power line passage hole <NUM> may be formed in the lower case <NUM> or the upper case <NUM>.

Unlike this, one power line passage hole <NUM> may be partially formed in each of the lower case <NUM> and the upper case <NUM>, and it may be formed as a whole in a state in which the lower case <NUM> and the upper case <NUM> are coupled.

When the adhesive <NUM> is applied to the power line passage hole <NUM>, it is possible to prevent moisture from entering the inside of the housing <NUM> through the power line passage hole <NUM>.

In order to prevent the adhesive <NUM> applied to the power line passage hole <NUM> from being separated and/or detached from the housing <NUM>, the inner surface of the housing <NUM> around the power line passage hole <NUM> is provided with an adhesive receiving groove <NUM> formed larger than the power line passage hole <NUM> and in which a portion of the adhesive <NUM> is positioned.

Therefore, it is possible to prevent the adhesive <NUM> applied to the power line passage hole <NUM> from being separated and/or detached from the power line passage hole <NUM>.

A seating part 31a on which a protruding jaw 33a of the middle plate <NUM> is seated is formed at an upper end of the lower case <NUM> of the housing <NUM>.

In addition, a first seal ring R1 is disposed on the seating part 31a of the lower case <NUM>.

The first seal ring R1 is supported by a lower end of the upper case <NUM>, the seating part 31a of the lower case <NUM>, and the protruding jaw 33a of the middle plate <NUM>, respectively.

According to this configuration, the first seal ring R1 is pressed in the vertical (Y-Y') direction by the upper case <NUM> and the lower case <NUM>.

In addition, the first seal ring R1 is pressed in the horizontal (X-X') direction by the protruding jaw 33a of the middle plate <NUM> and the seating part 31a of the lower case <NUM>, or supported in the horizontal (X-X') direction by the protruding jaw 33a of the middle plate <NUM> and the seating part 31a of the lower case <NUM>.

Therefore, when the upper case <NUM> and the lower case <NUM> contract and expand due to the temperature difference during use of the valve actuator, it is possible to prevent airtightness from deteriorating due to a minute gap between the upper case <NUM> and the lower case <NUM>.

The motor <NUM> and the gear assembly <NUM> are disposed in a space formed by the lower case <NUM> and the middle plate <NUM> in the inner space of the housing <NUM>.

When the motor <NUM> and the gear assembly <NUM> are disposed in the space formed by the lower case <NUM> and the middle plate <NUM> in the inner space of the housing <NUM>, the length of the rotation shaft of the motor <NUM> and the shaft coupled to the gears of the gear assembly <NUM> may be formed short, and the size of the space formed by the middle plate <NUM> and the upper case <NUM> may be reduced. Accordingly, the size of the valve actuator may be reduced.

The motor <NUM> may be a type of motor with precise rotational control. However, this is not essential and may be a type of motor with imprecise rotational control. Also, the motor <NUM> may be a normal/reverse rotation motor.

The gear assembly <NUM> includes an input gear <NUM> coupled to a rotation shaft <NUM> of the motor <NUM> and rotating together with the rotation shaft <NUM>, and an output gear <NUM> positioned apart from the input gear <NUM> in the horizontal (X-X') direction.

The gear assembly <NUM> further includes power transmission gears <NUM> and <NUM> that transmit the rotational force of the input gear <NUM> to the output gear <NUM>.

The output gear <NUM> is coupled to the stem <NUM> of the ball valve <NUM> and transmits the rotational force of the input gear <NUM> to the stem <NUM> of the ball valve <NUM>.

In the present disclosure, the power transmission gear includes a first gear set <NUM> and a second gear set <NUM> disposed adjacent to the first gear set <NUM> in the horizontal (X-X ') direction.

The first gear set <NUM> includes a clutch shaft <NUM> having both ends coupled to the middle plate <NUM> and the lower case <NUM> so as to be movable in the vertical (Y-Y') direction.

In addition, the first gear set <NUM> further includes a first gear <NUM> and a second gear <NUM> that are coupled to the clutch shaft <NUM> and disengaged from each other or coupled to each other by the movement of the clutch shaft <NUM> in the vertical (Y-Y') direction.

The clutch shaft <NUM> and the first gear set <NUM> constitute a clutch unit in the valve actuator of the present disclosure.

If the clutch unit is not operated in a state in which the motor <NUM> is driven and the ball valve <NUM> blocks the flow of refrigerant, when trying to return the ball valve <NUM> to its original position (a position where refrigerant flow is possible) in a state where the gears of the gear assembly are meshed with each other, there is a possibility that the teeth of the gears provided in the gear assembly may be damaged.

In order to solve this problem, a clutch unit may be provided in the valve actuator.

By the way, in the conventional valve actuator, as disclosed in <CIT>, the clutch unit is installed on the output shaft of the gear assembly.

Therefore, since the output shaft moves in two directions, a rotational direction and a vertical (Y-Y') direction, there is a problem in that sealing performance is deteriorated, and since the output shaft has to move in the vertical (Y-Y') direction there is a problem in that the size of the product increases.

In addition, since a large rigid return spring is required to return the output shaft, and the engagement between the gear teeth is directly disengaged, there is a problem in that gear teeth are adversely affected.

However, according to the structure of the clutch unit of the present disclosure, since the middle shaft (shaft of the power transmission gear) of the gear train, not the output shaft, is formed as the clutch shaft <NUM>, the clutch shaft <NUM> can be operated with less force compared to the case where the output shaft is used as the clutch shaft.

In addition, since the first gear <NUM> and the second gear <NUM> may be coupled or disengaged according to the movement of the clutch shaft <NUM> in the vertical (Y-Y') direction, when the clutch shaft <NUM> is operated, coupling between gears is disengaged, not disengagement of coupling between gear teeth.

Therefore, when the clutch shaft <NUM> moves in the vertical (Y-Y') direction, the influence on the teeth of the input gear <NUM>, the output gear <NUM>, and the power transmission gears <NUM> and <NUM> can be minimized.

A coupling part 133a for coupling the first gear <NUM> to the second gear <NUM> protrudes from the lower surface of the first gear <NUM> coupled to the input gear <NUM>.

In addition, a coupling part insertion groove 135a into which the coupling part 133a of the first gear <NUM> is inserted is formed on the upper surface of the second gear <NUM>.

The coupling part 133a and the coupling part insertion groove 135a may be formed in shapes corresponding to each other.

Although the accompanying drawings show that the planar shape of the coupling part 133a and the coupling part insertion groove 135a is formed in a spline shape, the planar shape of the coupling part 133a and the coupling part insertion groove 135a may be formed in various shapes such as an ellipse or a polygon.

When the coupling part 133a of the first gear <NUM> is inserted into the coupling part insertion groove 135a of the second gear <NUM>, the height or thickness of the first gear set <NUM> in the vertical (Y-Y') direction may be reduced.

Accordingly, since the size of the space formed by the middle plate <NUM> and the lower case <NUM> can be reduced, the size of the valve actuator can be reduced.

A push-up part 131a is formed on the clutch shaft <NUM> to push the first gear <NUM> upward in contact with the coupling part 133a of the first gear <NUM>.

In addition, a push-up part insertion groove 133b is formed on the lower surface of the coupling part 133a of the first gear <NUM>.

Therefore, the push-up part 131a of the clutch shaft <NUM> is inserted into the push-up part insertion groove 133b formed on the lower surface of the coupling part 133a of the first gear <NUM>.

When the push-up part 131a of the clutch shaft <NUM> is inserted into the push-up part insertion groove 133b formed on the lower surface of the coupling part 133a of the first gear <NUM>, the height or thickness of the first gear set <NUM> in the vertical (Y-Y') direction may be reduced.

Therefore, since the size of the space formed by the middle plate <NUM> and the lower case <NUM> can be further reduced, the size of the valve actuator can be further reduced.

A return spring <NUM> is disposed on the clutch shaft <NUM> above the first gear <NUM>.

Accordingly, the first gear <NUM> may be pressed toward the second gear <NUM> by the return spring <NUM>.

According to this configuration, the first gear <NUM> and the second gear <NUM> are kept coupled with each other between the gears before the valve actuator operates.

That is, before the operation of the valve actuator, since the coupling part 133a of the first gear <NUM> is coupled to the coupling part insertion groove 135a of the second gear <NUM>, the first gear <NUM> and the second gear <NUM> are kept coupled with each other between the gears.

In addition, after the operation of the valve actuator when the clutch shaft <NUM> is pressed from the bottom to the top to return the ball valve to its original position, while the return spring <NUM> is pressed, the first gear <NUM> is pushed up by the push-up part 131a, and accordingly, the coupling between the first gear <NUM> and the second gear <NUM> is disengaged.

In this state, when pressing of the clutch shaft <NUM> is disengaged while rotating the output shaft <NUM> by inserting a tool such as a screwdriver into a groove formed at the upper end of the output shaft <NUM>, the first gear <NUM> is pressed downward by the return spring <NUM>.

Therefore, while the output shaft <NUM> of the output gear <NUM> rotates and the coupling part 133a of the first gear <NUM> is inserted into the coupling part insertion groove 135a of the second gear <NUM>, the first gear <NUM> and the second gear <NUM> are coupled again.

A snap ring <NUM> is installed on the clutch shaft <NUM> between the return spring <NUM> and the upper surface of the first gear <NUM>.

The snap ring <NUM> is provided on the clutch shaft <NUM> to allow the clutch shaft <NUM> to be manually pulled in case the clutch shaft <NUM> does not return to the original position due to the malfunction of the return spring <NUM>.

Therefore, when the first gear <NUM> does not move downward due to the malfunction of the return spring <NUM> despite the disengagement of the pressing of the clutch shaft <NUM>, when the clutch shaft <NUM> is pulled downward, the snap ring <NUM> moves downward together with the clutch shaft <NUM>, so that the coupling part 133a of the first gear <NUM> is coupled to the coupling part insertion groove 135a of the second gear <NUM>.

A third seal ring R3 is disposed on the clutch shaft below the second gear <NUM>.

In the lower case <NUM> where the clutch shaft <NUM> is coupled when the clutch shaft <NUM> moves in the vertical (Y-Y') direction, a guide groove 31a is formed to guide the third seal ring R3 to move in the vertical (Y-Y') direction together with the clutch shaft <NUM>, the guide groove 31a is formed extending to the inner surface of the lower case <NUM>.

Therefore, the moving distance of the clutch shaft <NUM> in the upward direction is set by a distance D3 between the third seal ring R3 and the second gear <NUM>.

In this way, by appropriately setting the distance D3 between the third seal ring R3 and the second gear <NUM>, the moving distance of the clutch shaft <NUM> in the upward direction can be adjusted.

In the state where the coupling between the gears of the first gear <NUM> and the second gear <NUM> is disengaged, the second gear <NUM> may be supported by the third seal ring R3 and/or the lower case <NUM>.

Therefore, in the state where the coupling between the gears of the first gear <NUM> and the second gear <NUM> is disengaged, the downward movement of the second gear <NUM> may be limited by the third sea ring R3 and/or the lower case <NUM>.

However, when the second gear <NUM> is spaced apart from the inner surface of the lower case <NUM> by a certain distance, it is also possible to further form a separate support shaft for supporting the second gear <NUM> outside the clutch shaft <NUM>.

In this case, in a state where the coupling between the gears of the first gear <NUM> and the second gear <NUM> is disengaged, the downward movement of the second gear <NUM> may be limited by a separate support shaft.

In addition, if a part of the second gear <NUM> is positioned below the motor <NUM> and a third gear <NUM>, when disengaging the coupling between the gears of the first gear <NUM> and the second gear <NUM>, the upward movement of the second gear <NUM> may be limited by the motor <NUM> and the second gear set <NUM>.

The second gear set <NUM> is disposed adjacent to the first gear set <NUM> in the horizontal (X-X') direction.

The second gear set <NUM> is coupled to the first gear <NUM> and includes the third gear <NUM> in which a part of the second gear <NUM> is positioned at the lower portion.

In addition, the second gear set <NUM> is positioned above the third gear <NUM> and further includes a fourth gear <NUM> that rotates integrally with the third gear <NUM> and is coupled to the output gear <NUM>.

The third gear <NUM> and the fourth gear <NUM> constituting the second gear set <NUM> may be formed as one body, or may be manufactured separately and coupled between gears with a structure similar to that of the first and second gears <NUM> and <NUM>.

According to this configuration, since the power transmission gear is composed of the first gear set <NUM> and the second gear set <NUM>, the configuration of the gear assembly <NUM> can be simplified.

The lower end of the output shaft <NUM> coupled with the output gear <NUM> is coupled to the stem <NUM> of the ball valve <NUM>, and the upper end of the output shaft <NUM> protrudes out of the upper case <NUM>.

In addition, a fourth seal ring R4 is disposed between the output shaft <NUM> and the lower case <NUM> between the lower end of the output shaft <NUM> and the output gear <NUM>.

According to this configuration, it is possible to prevent the refrigerant flowing along the ball valve <NUM> from entering the inside of the valve actuator through a minute gap formed between the output shaft <NUM> and the lower case <NUM>.

A fifth seal ring R5 is disposed between the output shaft <NUM> and the upper case between the upper end of the output shaft <NUM> and the output gear <NUM>.

According to this configuration, it is possible to prevent moisture from entering the inside of the housing <NUM> through a minute gap formed between the upper case <NUM> and the output shaft <NUM>.

In the upper case <NUM>, a cap R6 covering the upper end of the output shaft <NUM> protruding out of the upper case <NUM> is installed.

In addition, the cap R6 covers the minute gap between the output shaft <NUM> and the upper cover <NUM>.

According to this configuration, it is possible to more effectively prevent moisture from entering the inside of the housing <NUM> through the minute gap formed between the upper case <NUM> and the output shaft <NUM>.

In the above, the valve actuator for controlling the ball valve provided in the air conditioning system has been described, but the valve actuator of the present disclosure can be applied to other valves for controlling a flow path of gas or fluid.

Claim 1:
A valve actuator comprising:
a housing (<NUM>);
a motor (<NUM>) disposed in an inner space of the housing (<NUM>); and
a gear assembly (<NUM>) disposed in the inner space of the housing (<NUM>) and transmitting a driving force of the motor (<NUM>) to a ball valve (<NUM>),
wherein the gear assembly (<NUM>) includes:
an input gear (<NUM>) coupled to a rotation shaft of the motor (<NUM>) and rotating together with the rotation shaft;
an output gear (<NUM>) positioned apart from the input gear (<NUM>) in a horizontal direction, coupled to a stem (<NUM>) of the ball valve (<NUM>), and transmitting a rotational force of the input gear (<NUM>) to the stem (<NUM>); and
a power transmission gear (<NUM>, <NUM>) transmitting the rotational force of the input gear (<NUM>) to the output gear (<NUM>),
wherein the power transmission gear (<NUM>, <NUM>) includes a first gear set (<NUM>) positioned between the input gear (<NUM>) and the output gear (<NUM>),
wherein the first gear set (<NUM>) includes:
a clutch shaft (<NUM>) installed in the housing (<NUM>) so as to be movable in a vertical direction; and
a first gear (<NUM>) and a second gear (<NUM>) coupled to the clutch shaft (<NUM>) and disengaged from each other or coupled to each other by vertical movement of the clutch shaft (<NUM>),
characterized in that a coupling part (133a) for coupling the first gear (<NUM>) to the second gear (<NUM>) is protruded from a lower surface of the first gear (<NUM>) coupled to the input gear (<NUM>), and a coupling part insertion groove (135a) into which the coupling part (133a) of the first gear (<NUM>) is inserted is formed on an upper surface of the second gear (<NUM>), and
wherein a push-up part (131a) is formed on the clutch shaft (<NUM>) to push the first gear (<NUM>) upward in contact with the coupling part (133a) of the first gear (<NUM>), and the push-up part (131a) is positioned in a push-up part insertion groove (133b) formed on a lower surface of the coupling part (133a) of the first gear (<NUM>).