Patent Description:
Typically, a ball valve is an opening/closing means that is widely used to supply or cut off the supply of a working fluid to a required place through a pipe coupled to two opposite sides of the main body of the valve by opening and closing the pipe by automatically rotating a ball thereinside by way of a motor.

A conventional ball valve actuator connects the shaft of the gear motor with the output shaft of the ball valve through a cam and uses a sensor or step motor to turn the output shaft by an intended angle. In this case, a physical stopper is used to limit the rotation angle of the output shaft.

However, if torque is applied from the motor with the gear in contact with the stopper, the gear may be damaged.

To address this issue, <CIT> discloses controlling to stop the rotation of the motor, with the gear in contact with the stopper, through a limiter switch.

In this case, due to addition of components, such as a separate sensor for detecting contact of the gear to the stopper, a separate limiter switch, or a separate printed circuit board (PCB) for stop signals, the size of the product and manufacturing costs may increase.

<CIT> discloses a double offset valve in which a rotation shaft is eccentrically disposed from a center of a valve hole of a valve seat, and a sealing surface of the valve element is eccentrically disposed from the rotation shaft. <CIT> discloses a transmission device with overload protection. <CIT> discloses a motor with an integral magnetic torque limiting coupling. <CIT> discloses a double eccentric valve including a valve element provided with a rotatable shaft eccentrically disposed from a center of a valve opening of a valve seat. <CIT> discloses an actuator with an impact absorbing-type stopper. <CIT> discloses a torque limited motor operated valve.

An object of the disclosure is to provide a valve actuator capable of preventing damage to a gear when torque is applied from a motor with the gear in contact with a stopper.

Another object of the disclosure is to provide a valve actuator capable of damping the torque of a motor applied due to over-output.

Another object of the disclosure is to provide a valve actuator capable of reducing manufacturing costs.

Another object is to provide a valve actuator capable of operating even under a high-speed slip condition, e.g., at thousands of rpm.

Another object of the disclosure is to provide a valve actuator capable of lubricating a component to prevent damage to the component under a high-speed slip condition.

The present invention is defined by the appended independent claim, and preferred aspects of the present invention are defined by the appended dependent claims. According to an aspect of the disclosure, a valve actuator comprises a housing, a motor disposed on the housing, a drive gear coupled to a motor shaft of the motor, a transfer gear engaging with the drive gear and rotating according to a predetermined gear ratio when the drive gear rotates, an output gear coupled to an output shaft and engaging with the transfer gear, and a stopper disposed in the housing and limiting a rotation of the output gear.

The transfer gear comprises an outer part, an inner part disposed in the outer part, a first magnet disposed on the outer part, and a second magnet disposed on the inner part and facing the first magnet.

Thus, since the gear shaft idles due to the first magnet and the second magnet when the torque of the motor is applied, with the output gear and the stopper in contact with each other, it is possible to prevent damage to the drive gear, transfer gear, and output gear.

It is also possible to prevent damage to the gears without separate components, such as a sensor for detecting contact of the gear to the stopper, a limiter switch, or a PCB for stop signals, thus reducing the size and manufacturing costs of the product.

The first magnet and the second magnet may have different polarities.

An attractive force between the first magnet and the second magnet may be larger than an average output force of the motor and smaller than a maximum output force of the motor. Thus, since the gear shaft idles due to the first magnet and the second magnet during over-output of the motor, it is possible to damp the torque of the motor applied due to over-output and hence prevent damage to the drive gear, transfer gear, and output gear.

The first magnet may comprise a plurality of first magnet units having different polarities between adjacent magnet units, and the second magnet may comprise a plurality of second magnet units having different polarities between adjacent magnet units and individually facing the plurality of first magnet units.

The motor may be a DC motor. In other words, since it may be applied to DC motors that are inexpensive as compared with AC motors, it is possible to reduce the manufacturing costs of the product.

An upper end and lower end of the inner part are supported by an inner surface of the housing. An upper or lower end of the outer part is vertically supported by the inner part. A height of the first magnet is larger than a height of the second magnet. Thus, since the outer part is prevented from escaping off while maintaining a floating state with respect to the inner part, it may operate even under a high-speed slip condition, e.g., at thousands of rpm.

When the upper end of the outer part is vertically supported by the inner part, a vertical center of the first magnet may be disposed above a vertical center of the second magnet, and when the lower end of the outer part is vertically supported by the inner part, the vertical center of the first magnet may be disposed below the vertical center of the second magnet.

The inner part may comprise a groove formed in a region supporting the upper end or lower end of the outer part. A lubricant may be disposed in the groove. The lubricant may perform lubrication to prevent damage to the components under the high-speed slip condition.

The transfer gear may comprise a first gear engaging with the drive gear, a second gear engaging with the first gear, and a third gear engaging with the second gear. The first gear may comprise the outer part, the inner part, the first magnet, and the second magnet.

According to an aspect of the disclosure not falling into the scope of claim <NUM>, a valve actuator may comprise a housing, a motor disposed on the housing, a drive gear coupled to a motor shaft of the motor, an output gear coupled to an output shaft and engaging with the drive gear, and a stopper disposed in the housing and limiting a rotation radius of the output gear.

The drive gear may comprise an outer part, an inner part disposed in the outer part, a first magnet disposed on the outer part, and a second magnet disposed on the inner part and facing the first magnet.

Thus, since the gear shaft idles due to the first magnet and the second magnet when the torque of the motor is applied, with the output gear and the stopper in contact with each other, it is possible to prevent damage to the drive gear and output gear.

Further, since the gear shaft idles due to the first magnet and the second magnet during over-output of the motor, it is possible to damp the torque of the motor applied due to over-output and hence prevent damage to the drive gear and output gear.

The inner part may be coupled to a motor shaft and rotate along with the motor shaft. An upper or lower end of the outer part is vertically supported by the inner part. A height of the first magnet may be larger than a height of the second magnet. Thus, since the outer part is prevented from escaping off while maintaining a floating state with respect to the inner part, it may operate even under a high-speed slip condition, e.g., at thousands of rpm.

The inner part may comprise a groove formed in an area supporting the upper end or lower end of the outer part. A lubricant may be disposed in the groove. The lubricant may perform lubrication to prevent damage to the components under the high-speed slip condition.

According to an aspect of the disclosure, a valve actuator may comprise a housing, a motor disposed on the housing, a drive gear coupled to a motor shaft of the motor, a transfer gear engaging with the drive gear and rotating according to a first gear ratio when the drive gear rotates, an output gear coupled to an output shaft and engaging with the transfer gear, and a stopper disposed in the housing and limiting a rotation radius of the output gear.

The transfer gear may comprise a first transfer gear, a second transfer gear rotating according to a second gear ratio when the first transfer gear rotates, a cylindrical first magnet disposed on the first transfer gear, and a cylindrical second magnet disposed on the second transfer gear. The first magnet and the second magnet may horizontally overlap each other, with a predetermined gap formed therebetween.

Further, since the gear shaft idles due to the first magnet and the second magnet during over-output of the motor, it is possible to damp the torque of the motor applied due to over-output and hence prevent damage to the drive gear, transfer gear, and output gear.

According to an aspect of the disclosure not failing into the scope of claim <NUM>, a valve actuator may comprise a housing, a motor disposed on the housing, a drive gear coupled to a motor shaft of the motor, a cylindrical first magnet coupled to the drive gear, an output gear coupled to an output shaft, a cylindrical second magnet coupled to the output gear, and a stopper disposed in the housing and limiting a rotation radius of the output gear.

The first magnet and the second magnet horizontally overlap each other, with a predetermined gap formed therebetween.

The first magnet may comprise a plurality of first magnet units circumferentially arranged, and the second magnet may comprise a plurality of second magnet units circumferentially arranged. The plurality of first magnet units may be magnetized to have different poles from neighboring magnet units, and the plurality of second magnet units may be magnetized to have different poles from neighboring magnet units. The first magnet unit and the second magnet unit facing each other, among the plurality of first magnet units and the plurality of second magnet units, may have different polarities.

The ratio of the number of the plurality of first magnet units to the number of the plurality of second magnet units may be identical to the second gear ratio.

According to the disclosure, it is possible to provide a valve actuator capable of preventing damage to a gear when torque is applied from a motor with the gear in contact with a stopper.

It is also possible to provide a valve actuator capable of damping the torque of a motor applied due to over-output.

It is also possible to provide a valve actuator capable of reducing manufacturing costs.

It is also possible to provide a valve actuator capable of operating even under a high-speed slip condition, e.g., at thousands of rpm.

It is also possible to provide a valve actuator capable of lubricating a component to prevent damage to the component under a high-speed slip condition.

A more complete appreciation of the disclosure and many of the attendant aspects thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:.

Hereinafter, exemplary embodiments of the disclosure are described in detail with reference to the accompanying drawings. The same reference denotations may be used to refer to the same or similar elements throughout the specification and the drawings, and no duplicate description is given.

It will be understood that when an element or layer is referred to as being "on," "connected to," "coupled to," or "adjacent to" another element or layer, it can be directly on, connected, coupled, or adj acent to the other element or layer, or intervening elements or layers may be present.

When determined to make the subject matter of the disclosure unclear, the detailed description of the known art or functions may be skipped. The accompanying drawings are provided merely for a better understanding of the disclosure, and the scope of the present invention are not limited by the drawings.

<FIG> is a front view illustrating a ball valve and a valve actuator according to a first embodiment of the disclosure. <FIG> is a perspective view illustrating a valve actuator according to the first embodiment of the disclosure. <FIG> is an exploded perspective view illustrating a valve actuator according to the first embodiment of the disclosure. <FIG> and <FIG> are perspective views illustrating some components of a valve actuator according to the first embodiment of the disclosure. <FIG> is a perspective view illustrating a first gear according to the first embodiment of the disclosure. <FIG> is a plan view illustrating a first gear according to the first embodiment of the disclosure. <FIG> is a cross-sectional view illustrating a valve actuator according to the first embodiment of the disclosure. <FIG> is an enlarged view illustrating some components of <FIG>. <FIG>, <FIG>, and <FIG> are views illustrating the operation of a valve actuator according to the first embodiment of the disclosure. <FIG> is an exploded perspective view illustrating a ball valve according to the first embodiment of the disclosure.

Referring to <FIG>, according to the first embodiment of the disclosure, a valve actuator <NUM> may include a housing <NUM>, a motor <NUM>, a drive gear <NUM>, transfer gears <NUM>, <NUM>, and <NUM>, an output gear <NUM>, an output shaft <NUM>, a stopper <NUM>, and a magnet <NUM>. However, the valve actuator <NUM> may omit some of the components or add more components.

The valve actuator <NUM> may be coupled to an upper portion of a plate <NUM> coupled to an upper portion of a ball valve <NUM>. The output shaft <NUM> of the actuator <NUM> may be coupled to a stem <NUM> of the ball valve <NUM>. As the output shaft <NUM> of the actuator <NUM> rotates, the stem <NUM> may rotate, and a ball <NUM> of the ball valve <NUM> may rotate, opening or closing the ball valve <NUM>. The ball valve <NUM> may include a stem fixing part <NUM> for coupling the stem <NUM> and an O-ring <NUM> disposed under the stem <NUM>.

The housing <NUM> may be formed in a hexahedral shape. The housing <NUM> may form the exterior of the valve actuator <NUM>. The housing <NUM> may be disposed on one side of the ball valve <NUM>. The housing <NUM> may be disposed on the ball valve <NUM>. In the housing <NUM>, the motor <NUM>, the drive gear <NUM>, the transfer gears <NUM>, <NUM>, and <NUM>, the output gear <NUM>, the output shaft <NUM>, and the stopper <NUM> may be disposed.

The motor <NUM> may be disposed on the housing <NUM>. The motor <NUM> may be coupled to a recess of the housing <NUM> so that one side thereof may be disposed in the housing <NUM>, and the other side may protrude to the outside of the housing <NUM>. This may enhance space efficiency. The drive gear <NUM> may be coupled to a motor shaft of the motor <NUM>.

The motor <NUM> may a direct current (DC) motor. The motor <NUM> may be an alternating current (AC) motor. When the motor <NUM> is a DC motor, the manufacturing costs of the valve actuator <NUM> may be reduced as compared with when the motor <NUM> is an AC motor. A DC motor may present poor rpm control accuracy as compared with an AC motor, and this may be supplemented by the physical stopper <NUM> of the valve actuator.

The drive gear <NUM> may be coupled to the motor shaft of the motor <NUM>. When the motor shaft of the motor <NUM> rotates in a first direction, the drive gear <NUM> may rotate in the first direction and, when the motor shaft rotates in a second direction, the drive gear <NUM> may rotate in the second direction. The drive gear <NUM> may engage with the transfer gears <NUM>, <NUM>, and <NUM>. The drive gear <NUM> may be an external gear.

The transfer gears <NUM>, <NUM>, and <NUM> may engage with the drive gear <NUM>. The transfer gears <NUM>, <NUM>, and <NUM> may rotate according to a predetermined gear ratio when the drive gear <NUM> rotates. The transfer gears <NUM>, <NUM>, and <NUM> may engage with the output gear <NUM>. The transfer gears <NUM>, <NUM>, and <NUM> may reduce the speed of the drive gear <NUM> at a predetermined gear ratio and transfer it to the output gear <NUM>. Thus, the transfer gears <NUM>, <NUM>, and <NUM> may increase the torque transferred from the drive gear <NUM> and transfer it to the output gear <NUM>.

The transfer gears <NUM>, <NUM>, and <NUM> may include a first gear <NUM>, a second gear <NUM>, and a third gear <NUM>.

The first gear <NUM> may engage with the drive gear <NUM>. The first gear <NUM> may engage with the second gear <NUM>. The first gear <NUM> may engage with the drive gear <NUM> and may rotate at a predetermined gear ratio with respect to the drive gear <NUM>. The first gear <NUM> may engage with the second gear <NUM> to rotate the second gear <NUM> at a predetermined gear ratio with respect to the first gear <NUM>.

The first gear <NUM> may include an outer part <NUM>, a first external gear <NUM>, an inner part <NUM>, a second external gear <NUM>, and magnets <NUM>.

The outer part <NUM> may be disposed outside the inner part <NUM>. The outer part <NUM> may be radially spaced apart from the inner part <NUM>. The first external gear <NUM> may be formed on the outer part <NUM>. The first magnet <NUM> may be disposed on the outer part <NUM>.

The first external gear <NUM> may engage with the drive gear <NUM>. Thus, the outer part <NUM> of the first gear <NUM> may rotate at a predetermined gear ratio with respect to the drive gear <NUM>.

The magnets <NUM> may include a first magnet <NUM> disposed on the outer part <NUM> and a second magnet <NUM> disposed on the inner part <NUM>. The first magnet <NUM> may be radially spaced apart from the second magnet <NUM>. For example, a predetermined gap g1 may be formed between the inner surface of the first magnet <NUM> and the outer surface of the second magnet <NUM>. The second magnet <NUM> may be disposed in the first magnet <NUM>.

The first magnet <NUM> and the second magnet <NUM> may have different polarities. The respective areas of the first magnet <NUM> and the second magnet <NUM>, which face each other, may have different polarities. For example, if a first area of the first magnet <NUM> has an N pole, a first area of the second magnet <NUM> facing the first area of the first magnet <NUM> may have an S pole. The first magnet <NUM> may rotate according to the rotation of the outer part <NUM>, and the second magnet <NUM> may rotate along with the first magnet <NUM> by magnetic force.

Thus, when the torque of the motor <NUM> is applied while the output gear <NUM> and the stopper <NUM> are in contact, the outer part <NUM> idles with respect to the inner part <NUM> due to the first magnet <NUM> and the second magnet <NUM>, preventing damage to the drive gear <NUM>, the transfer gears <NUM>, <NUM>, and <NUM>, and the output gear <NUM>.

Further, it is possible to prevent damage to the drive gear <NUM>, the transfer gears <NUM>, <NUM>, and <NUM>, and the output gear <NUM> without separate components, such as a sensor for detecting contact of the output gear <NUM> to the stopper <NUM>, a limiter switch, or a PCB for stop signals, thus reducing the size and manufacturing costs of the product.

The attractive force between the first magnet <NUM> and the second magnet <NUM> may be larger than the average output of the motor <NUM> and smaller than the maximum output of the motor <NUM>. Thus, when the motor <NUM> over-outputs, the outer part <NUM> idles with respect to the inner part <NUM> due to the first magnet <NUM> and the second magnet <NUM>, damping the torque of the motor <NUM> applied due to the over-output and hence preventing damage to the drive gear <NUM>, the transfer gears <NUM>, <NUM>, and <NUM>, and the output gear <NUM>. In particular, this may compensate for the over-output of the motor <NUM> that may occur if the motor <NUM> is formed of a low-cost DC motor.

The first magnet <NUM> may include a plurality of first magnet units <NUM>, <NUM>, <NUM>, and <NUM> having polarities different from those of adjacent magnet units. The second magnet <NUM> may include a plurality of second magnet units <NUM>, <NUM>, <NUM>, and <NUM> having different polarities from those of adj acent magnet units and facing the plurality of first magnet units <NUM>, <NUM>, <NUM>, and <NUM>, respectively. For example, a <NUM>-1th magnet unit <NUM> may have an N pole, a <NUM>-2th magnet unit <NUM> may have an S pole, a <NUM>-3th magnet unit <NUM> may have an N pole, and a <NUM>-4th magnet unit <NUM> may have an S pole. A <NUM>-1th magnet unit <NUM> may have an S pole, a <NUM>-2th magnet unit <NUM> may have an N pole, a <NUM>-3th magnet unit <NUM> may have an S pole, and a <NUM>-4th magnet unit <NUM> may have an N pole. In the first embodiment of the disclosure, the number of the plurality of first magnet units <NUM>, <NUM>, <NUM>, and <NUM> and the number of the plurality of second magnet units <NUM>, <NUM>, <NUM>, and <NUM> each are four. However, the number of first magnet units and the number of second magnet units each may be two.

The inner part <NUM> may be disposed in the outer part <NUM>. The inner part <NUM> may be radially spaced apart from the outer part <NUM>. The second external gear <NUM> may be formed on the inner part <NUM>. The second magnet <NUM> may be disposed on the outer part <NUM>. The outer part <NUM> may rotate according to the rotation of the second magnet <NUM>.

An upper end and lower end of the inner part <NUM> are supported by the inner surface of the housing <NUM>, and an upper or lower end of the outer part <NUM> is vertically supported by the inner part <NUM>. The height of the first magnet <NUM> is larger than the height of the second magnet <NUM>. Thus, since the outer part <NUM> is prevented from escaping off while maintaining a floating state with respect to the inner part <NUM>, it may operate even under a high-speed slip condition, e.g., at thousands of rpm.

As illustrated in <FIG>, when the lower end of the outer part <NUM> is vertically supported by the inner part <NUM>, a vertical center of the first magnet <NUM> may be disposed below a vertical center of the second magnet <NUM>.

Alternatively, when the upper end of the outer part <NUM> is vertically supported by the inner part <NUM>, the vertical center of the first magnet <NUM> may be disposed above the vertical center of the second magnet <NUM>.

The inner part <NUM> may include grooves <NUM> and <NUM> formed in an area supporting the upper end or lower end of the outer part <NUM>. In this case, the valve actuator <NUM> may include a lubricant disposed in the grooves <NUM> and <NUM>. The lubricant may lubricate the inner part <NUM> and the outer part <NUM> to prevent damage to the inner part <NUM> and the outer part <NUM> under the high-speed slip condition.

The second external gear <NUM> may be formed on the inner part <NUM>. The second external gear <NUM> may be vertically spaced apart from the first external gear <NUM>. This may enhance space efficiency. A radial size of the second external gear <NUM> may be smaller than a radial size of the first external gear <NUM>. The second external gear <NUM> may engage with the second gear <NUM>. The second external gear <NUM> may rotate the second gear <NUM> at a predetermined gear ratio with respect to the first gear <NUM>.

The second gear <NUM> may engage with the first gear <NUM>. The second gear <NUM> may engage with the third gear <NUM>. The second gear <NUM> may engage with the first gear <NUM> and may rotate at a predetermined gear ratio with respect to the first gear <NUM>. The second gear <NUM> may engage with the third gear <NUM> to rotate the third gear <NUM> at a predetermined gear ratio with respect to the second gear <NUM>.

The second gear <NUM> may include a third external gear <NUM> and a fourth external gear <NUM>. The third external gear <NUM> may engage with the second external gear <NUM> of the first gear <NUM>, and the fourth external gear <NUM> may engage with the third gear <NUM>. The third external gear <NUM> and the fourth external gear <NUM> may be vertically spaced apart from each other. This may enhance space efficiency. A radial size of the fourth external gear <NUM> may be smaller than a radial size of the third external gear <NUM>.

The third gear <NUM> may engage with the second gear <NUM>. The third gear <NUM> may engage with the output gear <NUM>. The third gear <NUM> may engage with the second gear <NUM> and may rotate at a predetermined gear ratio with respect to the second gear <NUM>. The third gear <NUM> may engage with the output gear <NUM> to rotate the output gear <NUM> at a predetermined gear ratio with respect to the third gear <NUM>.

The third gear <NUM> may include a fifth external gear <NUM> and a sixth external gear <NUM>. The fifth external gear <NUM> may engage with the fourth external gear <NUM> of the second gear <NUM>, and the sixth external gear <NUM> may engage with the output gear <NUM>. The fifth external gear <NUM> and the sixth external gear <NUM> may be vertically spaced apart from each other. This may enhance space efficiency. A radial size of the fifth external gear <NUM> may be larger than a radial size of the sixth external gear <NUM>.

In the embodiment of the disclosure, as an example, the transfer gears <NUM>, <NUM>, and <NUM> are described as including three gears, but the transfer gears <NUM>, <NUM>, and <NUM> may be understood as including one or more gears.

The output gear <NUM> may engage with the transfer gears <NUM>, <NUM>, and <NUM>. The output gear <NUM> may be coupled to the output shaft <NUM>. The rotation radius of the output gear <NUM> may be limited by the stopper <NUM>. The output gear <NUM> may be rotated in one direction or another direction by the transfer gears <NUM>, <NUM>, and <NUM> to rotate the output shaft <NUM> in the one direction or the other direction.

The output shaft <NUM> may be disposed in the housing <NUM>. The output shaft <NUM> may pass through the housing <NUM>, and one side thereof may be coupled to the output gear <NUM> while the opposite side thereof may be coupled to the stem <NUM> of the ball valve <NUM>. The output shaft <NUM> may be rotated in one direction or another direction by the output gear <NUM> to rotate the stem <NUM> of the ball valve <NUM> in the one direction or the other direction. Thus, the ball valve <NUM> may be opened and closed.

The stopper <NUM> may be disposed in the housing <NUM>. The stopper <NUM> may be formed on an inner surface of the housing <NUM>. The stopper <NUM> may be disposed within a rotation radius of the output gear <NUM>. The stopper <NUM> may limit the rotation angle of the output gear <NUM>.

The operation of the valve actuator <NUM> is described with reference to <FIG>.

Assuming that the state illustrated in <FIG> is an initial state, the inside of the ball valve <NUM> may be in an open state in the initial state.

Referring to <FIG>, when the motor <NUM> rotates the drive gear <NUM> in a first direction, the first gear <NUM> engaging with the drive gear <NUM> may rotate in a second direction, the second gear <NUM> engaging with the first gear <NUM> may rotate in the first direction, and the third gear <NUM> engaging with the second gear <NUM> may rotate in the second direction, the output gear <NUM> engaging with the third gear <NUM> may rotate in the first direction, and the output shaft <NUM> coupled with the output gear <NUM> may rotate in the first direction, allowing the inside of the ball valve <NUM> to turn into a closed state. In this case, the rotation radius of the output gear <NUM> may be limited by the stopper <NUM>, preventing damage to the ball valve <NUM>.

Referring to <FIG>, when the motor <NUM> rotates the drive gear <NUM> in the second direction, the first gear <NUM> engaging with the drive gear <NUM> may rotate in the first direction, the second gear <NUM> engaging with the first gear <NUM> may rotate in the second direction, and the third gear <NUM> engaging with the second gear <NUM> may rotate in the first direction, the output gear <NUM> engaging with the third gear <NUM> may rotate in the second direction, and the output shaft <NUM> coupled with the output gear <NUM> may rotate in the second direction, allowing the inside of the ball valve <NUM> to turn into a closed state. In this case, the rotation radius of the output gear <NUM> may be limited by the stopper <NUM>, preventing damage to the ball valve <NUM>.

As illustrated in <FIG> and <FIG>, even when the inside of the ball valve <NUM> is in the closed state, the motor <NUM> may continue to operate. In this case, the outer part <NUM> idles with respect to the inner part <NUM> due to the first magnet <NUM> and the second magnet <NUM>, preventing damage to the drive gear <NUM>, the transfer gears <NUM>, <NUM>, and <NUM>, and the output gear <NUM>.

In the first embodiment of the disclosure, the magnets <NUM> have been described as being disposed in the first gear <NUM> as an example, but the magnets <NUM> may be disposed in the second gear <NUM> or the third gear <NUM>. However, when the magnets <NUM> are disposed in the first gear <NUM>, it is possible to effectively prevent damage to the product as compared to the magnets <NUM> disposed in the second gear <NUM> or the third gear <NUM>.

<FIG> is a view schematically illustrating a first gear according to a second embodiment of the disclosure.

Referring to <FIG>, according to the second embodiment of the disclosure, the plurality of first magnet units of the first magnet <NUM> disposed on the first gear <NUM> may be spaced apart from each other in the circumferential direction, and the plurality of second magnet units of the second magnet <NUM> may be spaced apart from each other in the circumferential direction.

The plurality of first magnet units of the first magnet <NUM> may be individually mounted in a plurality of grooves formed in the inner surface of the outer part <NUM>. The plurality of second magnet units of the second magnet <NUM> may be individually mounted in a plurality of grooves formed in the outer surface of the inner part <NUM>.

The second embodiment of the disclosure may enhance the stability of the product by increasing the coupling force of the magnets <NUM> to the first gear <NUM> as compared to the first embodiment.

<FIG> is a cross-sectional view illustrating a valve actuator according to a third embodiment of the disclosure.

Referring to <FIG>, according to the third embodiment of the disclosure, a valve actuator may include a housing <NUM>, a motor <NUM> disposed on the housing <NUM>, a drive gear <NUM> coupled to a motor shaft of the motor <NUM>, an output gear <NUM> coupled to an output shaft <NUM> and engaging with the drive gear <NUM>, and a stopper <NUM> disposed in the housing <NUM> and limiting a rotation radius of the output gear <NUM>.

It may be appreciated that detailed configurations of the valve actuator not described in connection with the third embodiment of the disclosure are identical the detailed configurations of the valve actuator <NUM> according to the first embodiment of the disclosure.

It may be appreciated that the valve actuator according to the third embodiment of the disclosure omits the transfer gears <NUM>, <NUM>, and <NUM> of the valve actuator <NUM>, and the magnets <NUM> are installed in the drive gear <NUM>.

The drive gear <NUM> may be coupled to the motor shaft of the motor <NUM> and may be rotated in a first direction or second direction by the motor <NUM>. The drive gear <NUM> may engage with the output gear <NUM> to rotate the output gear <NUM> at a predetermined gear ratio.

The drive gear <NUM> may include an outer part, an inner part disposed inside the outer part, a first magnet disposed on the outer part, and a second magnet disposed on the inner part and facing the first magnet. The inner part of the drive gear <NUM> may be coupled to the motor shaft of the motor <NUM>, and the outer part of the drive gear <NUM> may engage with the output gear <NUM>.

Thus, when the torque of the motor <NUM> is applied while the output gear <NUM> and the stopper <NUM> are in contact, the inner part of the drive gear <NUM> idles with respect to the outer part <NUM> of the drive gear <NUM> due to the first magnet and the second magnet of the drive gear <NUM>, preventing damage to the drive gear <NUM> and the output gear <NUM>.

Further, it is possible to prevent damage to the drive gear <NUM> and the output gear <NUM> without separate components, such as a sensor for detecting contact of the output gear <NUM> to the stopper <NUM>, a limiter switch, or a PCB for stop signals, thus reducing the size and manufacturing costs of the product.

Further, when the motor <NUM> over-outputs, the inner part of the drive gear <NUM> idles with respect to the outer part of the drive gear <NUM> due to the first magnet and the second magnet of the drive gear <NUM>, damping the torque of the motor <NUM> applied due to the over-output and hence preventing damage to the drive gear <NUM> and the output gear <NUM>.

The inner part of the drive gear <NUM> may be coupled to the motor shaft of the motor <NUM> to rotate together with the motor shaft. The upper end or the lower end of the outer part of the drive gear <NUM> may be vertically supported by the inner part of the drive gear <NUM>. The height of the first magnet of the drive gear <NUM> is larger than the height of the second magnet of the drive gear <NUM>. Thus, since the outer part of the drive gear <NUM> is prevented from escaping off while maintaining a floating state with respect to the inner part of the drive gear <NUM>, it may operate even under a high-speed slip condition, e.g., at thousands of rpm.

When the upper end of the outer part of the drive gear <NUM> is vertically supported by the inner part of the drive gear <NUM>, a vertical center of the first magnet of the drive gear <NUM> may be disposed above a vertical center of the second magnet of the drive gear <NUM>.

When the lower end of the outer part of the drive gear <NUM> is vertically supported by the inner part of the drive gear <NUM>, a vertical center of the first magnet of the drive gear <NUM> may be disposed below a vertical center of the second magnet of the drive gear <NUM>.

The inner part of the drive gear <NUM> may include a groove formed in an area supporting the upper end or the lower end of the outer part of the drive gear <NUM>. Lubricant may be placed in the groove. The lubricant may perform lubrication to prevent damage to the components under the high-speed slip condition.

<FIG> is a perspective view illustrating some components of a valve actuator according to a fourth embodiment of the disclosure. <FIG> is a plan view illustrating some components of a valve actuator according to the fourth embodiment of the disclosure.

Referring to <FIG> and <FIG>, according to the fourth embodiment of the disclosure, a valve actuator may include a housing <NUM>, a motor <NUM> disposed on the housing <NUM>, a drive gear <NUM> coupled to a motor shaft of the motor <NUM>, transfer gears <NUM> and <NUM> engaging with the drive gear <NUM> and rotating according to a first gear ratio when the drive gear <NUM> rotates, an output gear <NUM> coupled to an output shaft <NUM> and engaging with the transfer gears <NUM> and <NUM>, and a stopper <NUM> disposed in the housing <NUM> and limiting a rotation radius of the output gear <NUM>.

It may be appreciated that detailed configurations of the valve actuator not described in connection with the fourth embodiment of the disclosure are identical the detailed configurations of the valve actuator <NUM> according to the first embodiment of the disclosure.

The transfer gears <NUM> and <NUM> may include a first transfer gear <NUM>, which engages with the drive gear <NUM> and rotates according to a first gear ratio with respect to the drive gear <NUM> when the drive gear <NUM> rotates, and a second transfer gear <NUM>, which rotates according to a second gear ratio with respect to the first transfer gear <NUM> when the first transfer gear <NUM> rotates. The second transfer gear <NUM> may engage with the output gear <NUM>.

The transfer gears <NUM> and <NUM> may include a cylindrical first magnet <NUM> disposed on the first transfer gear <NUM> and a cylindrical second magnet <NUM> disposed on the second transfer gear <NUM>. The first magnet <NUM> may be horizontally spaced apart from the second magnet <NUM>. For example, a predetermined gap g2 may be formed between the first magnet <NUM> and the second magnet <NUM>. The first magnet <NUM> and the second magnet <NUM> may overlap each other in a horizontal direction.

Thus, when the torque of the motor <NUM> is applied while the output gear <NUM> and the stopper <NUM> are in contact, the first transfer gear <NUM> idles with respect to the second transfer gear <NUM> due to the first magnet <NUM> and the second magnet <NUM>, preventing damage to the drive gear <NUM>, the transfer gears <NUM> and <NUM>, and the output gear <NUM>.

Further, it is possible to prevent damage to the drive gear <NUM>, the transfer gears <NUM> and <NUM>, and the output gear <NUM> without separate components, such as a sensor for detecting contact of the output gear <NUM> to the stopper <NUM>, a limiter switch, or a PCB for stop signals, thus reducing the size and manufacturing costs of the product.

Further, when the motor <NUM> over-outputs, the first transfer gear <NUM> idles with respect to the second transfer gear <NUM> due to the first magnet <NUM> and the second magnet <NUM>, damping the torque of the motor <NUM> applied due to the over-output and hence preventing damage to the drive gear <NUM>, the transfer gears <NUM> and <NUM>, and the output gear <NUM>.

The first magnet <NUM> may include a plurality of first magnet units arranged in a circumferential direction, and the second magnet <NUM> may include a plurality of second magnet units arranged in a circumferential direction.

The plurality of first magnet units may be magnetized to have different poles from neighboring magnet units, and the plurality of second magnet units may be magnetized to have different poles from neighboring magnet units. The first magnet unit and the second magnet unit facing each other, among the plurality of first magnet units and the plurality of second magnet units, may have different polarities. The ratio of the number of the plurality of first magnet units to the number of the plurality of second magnet units may be identical to the second gear ratio.

According to the fifth embodiment of the disclosure, a valve actuator may include a housing <NUM>, a motor <NUM> disposed on the housing <NUM>, a drive gear <NUM> coupled to a motor shaft of the motor <NUM>, a cylindrical first magnet <NUM> coupled to the drive gear <NUM>, an output gear <NUM> coupled to an output shaft <NUM>, a cylindrical second magnet <NUM> coupled to the output gear <NUM>, and a stopper <NUM> disposed in the housing <NUM> and limiting a rotation radius of the output gear <NUM>.

It may be appreciated that detailed configurations of the valve actuator not described in connection with the fifth embodiment of the disclosure are identical the detailed configurations of the valve actuator according to the fourth embodiment of the disclosure.

It may be appreciated that the valve actuator according to the fifth embodiment of the disclosure omits the transfer gears <NUM> and <NUM> of the valve actuator according to the fourth embodiment of the disclosure, and the first magnet <NUM> is coupled to the drive gear <NUM>, and the second magnet <NUM> is coupled to the output gear <NUM>.

Claim 1:
A valve actuator, comprising:
a housing (<NUM>);
a motor (<NUM>) disposed on the housing (<NUM>);
a drive gear (<NUM>) coupled to a motor shaft of the motor (<NUM>);
a transfer gear (<NUM>, <NUM>, <NUM>) engaging with the drive gear (<NUM>) and rotating according to a predetermined gear ratio when the drive gear (<NUM>) rotates;
an output gear (<NUM>) coupled to an output shaft (<NUM>) and engaging with the transfer gear (<NUM>, <NUM>, <NUM>); and
a stopper (<NUM>) disposed in the housing (<NUM>) and limiting a rotation of the output gear (<NUM>),
characterized in that the transfer gear (<NUM>, <NUM>, <NUM>) comprises an outer part (<NUM>), an inner part (<NUM>) disposed in the outer part (<NUM>), a first magnet (<NUM>) disposed on the outer part (<NUM>), and a second magnet (<NUM>) disposed on the inner part (<NUM>) and facing the first magnet (<NUM>), and in that an upper end and a lower end of the inner part (<NUM>) are supported by an inner surface of the housing (<NUM>), an upper or a lower end of the outer part (<NUM>) is vertically supported by the inner part (<NUM>), and a height of the first magnet (<NUM>) is larger than a height of the second magnet (<NUM>).