JP6520208B2 - Electric valve actuator - Google Patents

Description

  The present invention relates to a motorized valve actuator (hereinafter, also simply referred to as an actuator) capable of manually operating a valve from a location remote from the machine side.

  Conventionally, the actuator is configured to be drivable in both the motorized mode and the manual mode. Therefore, a clutch for switching between the electric mode and the manual mode is provided, and the clutch is provided with a manual lever for switching from the electric mode to the manual mode. On the other hand, switching from the manual mode to the electric mode is automatically performed by activating the electric motor.

  The actuators after being installed in various plants are usually driven in the electric mode, and the manual mode is required only at the time of periodical inspection of the plant or when the driving power is lost. When such a manual mode is required, the operator carries his foot to the side where the actuator is installed, operates the manual lever for switching the clutch, switches to the manual mode, and then rotates the manual handle. The valve is opened and closed.

  The plant is equipped with a large number of actuators, some of which require extremely high operating reliability. In addition, driving power is lost due to the occurrence of a disaster or the like, and in addition, depending on the installation environment, it may be difficult to approach the side of the actuator. In order to prepare for such a case, measures are taken so that the manual steering wheel can be turned from a location remote from the aircraft side. For example, in an actuator installed at a high position, a chain sprocket is attached to the manual handle, and the chain hooked to the chain sprocket is adapted to allow the manual handle to be turned from other than the machine side. In addition, the extension shaft can be attached to the shaft center of the manual handle, and the manual handle can be rotated even from a position away from the machine side (see, for example, Non-Patent Document 1).

  However, even if you take measures so that you can turn the manual handle from the location away from the machine side, if you can not switch the motorized mode to the manual mode by turning the manual lever, turn the manual handle. The valve can not be opened or closed. This is because the actuator is normally in the motorized mode.

  Here, as actuators, products of different sizes are made into a series to correspond to various types of valves. The worm gear is adopted as the reduction mechanism of the series actuator regardless of the size, but the mechanism for transmitting the rotation of the manual handle to the drive sleeve is different for small valve drive and large valve drive. .

  Since a large drive torque is required in an actuator for driving a large valve, the rotation of the manual handle is decelerated by a worm gear to drive the valve. Therefore, a clutch for switching from the manual mode to the electric mode is provided in the worm shaft system, and the connection between the motor shaft system and the worm shaft system is released by operating the manual lever. In addition, since the clutch is provided in the worm shaft system, the clutch for switching from the manual mode to the electric mode is added with the function of automatically disengaging (declutching) the clutch when the manual steering wheel is turned. The actuator for driving large valves is semi-standardly equipped with an automatic declutching function.

  Therefore, in a large valve drive actuator having an automatic declutch function, the motor side and the manual handle side are separated when the manual handle is turned without operating the manual lever, and the valve can be opened and closed by turning the manual handle. Also, when shifting from the manual mode to the electric mode, the manual handle is automatically disconnected when the motor starts to rotate.

  On the other hand, the manual handle is configured to rotate a drive sleeve provided inside the worm wheel, since a small drive actuator requires only a small drive torque. Therefore, a clutch for switching between the electric mode and the manual mode is provided in the worm wheel system, and the coupling between the worm wheel and the drive sleeve is released by operating the manual lever. As described above, the addition of the declutching function complicates the structure due to the provision of the clutch in the worm wheel system, so that actuators having an automatic declutching function are not commercially available for actuators for driving small valves.

  As a result, with commercially available actuators for driving small valves, it was necessary to operate the manual lever whenever shifting to the manual mode. Therefore, even if measures are taken so that the manual handle can be turned from a location away from the machine side, the manual lever can not be operated to switch from the electric mode to the manual mode, and the manual handle is away from the machine side It was not possible to turn the valve to open or close. When the manual mode is shifted to the electric mode, the manual handle is automatically disconnected when the motor starts to rotate. In this respect, the small valve drive actuator and the large valve drive actuator do not differ.

  Here, the valve is a valve that opens and closes by reciprocating motion of the stem like a gate valve or a ball valve, and a part-turn type valve that opens and closes by rotating the stem by about 90 degrees like a butterfly valve or a ball valve. There is. In an actuator for driving a gate valve which is opened and closed by reciprocation of a stem, the valve is opened and closed by rotation of a drive sleeve of the actuator for several tens of minutes. On the other hand, in part-turn type valves such as butterfly valves, since an extremely large reduction ratio is required, the actuator can not be installed directly on the valve, and a worm reduction gear as an auxiliary reduction gear is mounted on the valve. Attach and attach the actuator via this worm reducer. As a result, in the part-turn type valve, the rotation of the motor is reduced by the two-stage worm gear.

  The worm gear built into the auxiliary reduction gear needs to transmit large torque, so it becomes a relatively large worm gear, but the worm gear used for the actuator attached to the auxiliary reduction gear The torque is reduced by the reduction ratio, and a relatively small actuator is sufficient even for an actuator attached to a large part-turn valve.

Electric Actuator for industrial automation, AUMA, Germany Products Brochure No. Y006.065 Page 61, [Online], [Search on February 2, 2015], Internet: <URL: http: // 1424999127574_0>

  Conventionally, even for actuators that are attached to part-turn type valves via an auxiliary reduction gear, if the specification requires an automatic declutch function, select a large actuator even when the torque required to open and close the valve is small. It was Due to the fact that a small actuator with an automatic declutching function is not commercially available.

  However, selection of such a large-sized actuator causes not only a problem that the cost of the actuator becomes high but also a problem that the piping strength is insufficient due to the increase of the weight of the actuator.

  In particular, the lack of pipe strength becomes a big problem in the repair work of the existing plant. Large actuators are heavy, and installing them on existing piping lines may result in insufficient piping strength. In addition, in a plant with a dense piping line, it is not easy to provide reinforcement for supporting the piping.

  Therefore, it is an object of the present invention to provide an actuator that can operate a valve simply by turning a manual handle from a location remote from the machine side without requiring an automatic declutch function, and does not cause an increase in weight.

The invention according to claim 1 is an electric valve actuator attached to the input side of a reduction gear for driving a part-turn valve and for reducing the rotation of a motor by a worm and a worm wheel to drive the reduction gear , the reduction gear The worm gear has a self-locking function, while the worm gear of the motorized valve actuator does not have a self-locking function, and a drive sleeve is provided inside the worm wheel and connected to the reduction gear inside the drive sleeve The drive sleeve or the output shaft is provided with one end of a clutch, the other end of the clutch is provided with a manual handle, and the clutch is cut off by activation of the motor, and is stopped by stopping the motor The manual handle when connected and when the motor is stopped By simply rotating an electric valve actuator, characterized in that open and close the valve.

  The invention of claim 2 is characterized in that, in the motor-operated valve actuator according to claim 1, the number of worms of the worm is 2 or more and the lead angle is larger than the automatic tightening angle.

  The invention of claim 3 is characterized in that, in the motor-operated valve actuator according to claim 1 or 2, an extension shaft is connected to the axial center of the manual handle.

  The invention of claim 4 is characterized in that, in the motor-operated valve actuator according to claim 1 or 2, a chain sprocket is provided on the manual handle, and the chain is wound around the chain sprocket.

  According to the present invention, it is possible to realize an electric valve actuator which does not require a manual lever for switching between connection and disconnection of a clutch. As a result, the switching operation of the manual lever is not necessary. In addition, since the weight of the actuator does not increase, reinforcement of the piping line is not necessary even if the actuator is attached in the repair work of the existing plant. Therefore, the repair cost can be suppressed.

It is a top view which shows the whole structure of this invention. It is an AA arrow line view in FIG. It is a BB arrow line view in FIG.

  Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 3. These drawings are schematic diagrams for explaining the configuration of the present invention, and members not related to the description of the invention are omitted. FIG. 1 is a plan view showing an overall configuration in which an output shaft 6 of an actuator 5 is attached to an input shaft 3 of an auxiliary reduction gear 2 attached to a part-turn type valve 1 via a shaft joint 4. The shaft coupling 4 is not essential, and the input shaft 3 of the auxiliary reduction gear 2 and the output shaft 6 of the actuator 5 may be integrated, but in the present embodiment, the shaft coupling 4 is It is used.

  The actuator 7 incorporates a worm 7 and a worm wheel 8. The worm 7 is driven by a motor 9. The motor 9 is attached to the housing of the actuator 5. Further, the worm 7 is incorporated in the housing via a plurality of bearings (not shown).

  Inside the worm wheel 8 engaged with the worm 7, a drive sleeve 10 is provided, and the worm wheel 8 and the drive sleeve 10 are firmly fixed to rotate integrally. An output shaft 6 connected to the input shaft 3 of the auxiliary reduction gear 2 is provided inside the drive sleeve 10, and the output shaft 6 is rotated by the drive sleeve 10. Also, the drive sleeve 10 is incorporated into the housing via a plurality of bearings (not shown).

  The drive sleeve 10 is provided with one end 12 of the clutch 11. A manual handle 14 is provided on the other end 13 of the clutch 11. The clutch 11 is in the disengaged state when the motor 9 starts to be activated, and in the connected state when the motor 9 is stopped. Since the clutch 11 having such a function belongs to the well-known technology in the actuator 5, the description will be omitted. Further, the clutch 11 is not provided with a manual lever for operating connection / disconnection.

  Here, although the drive sleeve 10 and the output shaft 6 are configured as separate parts in consideration of ease of manufacture and ease of assembly, they functionally rotate synchronously as one unit. Therefore, one end 12 of the clutch 11 can be provided not on the drive sleeve 10 but on the output shaft 6. Further, the shaft coupling 4 is omitted, and the input shaft 3 of the auxiliary reduction gear 2 and the output shaft 6 of the actuator 5 are integrated, and the clutch 11 and the manual handle 14 are the shaft end side of the input shaft 3 of the auxiliary reduction gear 2 (FIG. 1 Can also be provided at the left end of

  The auxiliary reduction gear 2 is attached to the stem and valve box of the part turn valve 1. The part-turn valve 1 performs full closing and full opening when the valve body rotates approximately 90 degrees, and the auxiliary reduction gear 2 uses a worm reduction gear that can realize a large reduction ratio with a simple configuration. Further, the worm gear having a reduction ratio of a certain level or more has a characteristic function of self-locking (self-locking), so that there is an advantage that the position of the valve can be maintained without using an external brake or the like. From such circumstances, a worm gear is suitable for the auxiliary reduction gear of the part-turn valve.

  An actuator 5 is attached to the input side of the auxiliary reduction gear 2. Therefore, the part-turn valve 1 is driven by decelerating the rotation of the motor 9 by the two-step worm gear mechanism. Assuming that the speed reduction ratio of the auxiliary reduction gear is 1/60 and the speed reduction ratio of the actuator is 1/25, the speed reduction ratio 1/1500 can be realized with a simple configuration. If the motor is designed to rotate at 1,500 revolutions per minute, the valve can be fully opened or fully closed in one minute.

  Here, the self-locking function of the worm gear is sufficient if it exists in one place of the power transmission system, and if a plurality of worm gears are used for the power transmission system, it is necessary to give all worm gears a self-locking function. There is no. In the present embodiment, the worm gear of the auxiliary reduction gear 2 is provided with a self-locking function in consideration of downsizing of the entire device, while the worm gear of the actuator 5 is not provided with a self-locking function.

  However, an actuator incorporating a worm gear that does not have a self-locking function is nothing new. Whether or not the worm gear has a self-locking function depends on the lead angle of the worm, the coefficient of friction due to the surface finish of the meshing tooth surface, the sliding speed between the tooth surfaces, the characteristics of the lubricant, and the presence or absence of vibration at the installation location Under the influence of

  However, even if it can not be generally said under the influence of a plurality of factors, approximate limits at which the worm gear has a self-locking function can be assumed by those skilled in the art. For example, if the reduction ratio is 40 or more, the lead angle is around 5 degrees. Further, the coefficient of friction can be estimated if the gear material is determined, and if it is a combination of metal materials, it is about 0.15 or so, which is not a problem in practice. Therefore, there is no difficulty in realizing an actuator using a worm gear that does not have a self-locking function.

  One of the characteristic features of the present invention is that a large valve that is originally driven by the power of a motor can be operated manually in an emergency. Despite individual differences, there is a limit to human power. In order to perform manual operation manually, it is important that the power transmission efficiency of the actuator be good. From such a point of view, the lead angle of the worm, which is the most influential factor in improving the efficiency of the worm gear, is set to about 17 degrees or more, and the number of worm threads is also made plural to realize this lead angle. It goes without saying that a worm gear having such specifications does not have a self-locking function, but as a worm gear, it has a feature of high power transmission efficiency.

  In the present embodiment, the number of threads of the worm 7 incorporated in the actuator 5 is four, a lead angle of about 17 degrees is secured, and the number of teeth of the worm wheel 8 is fifty. That is, the reduction ratio is 1 / 12.5. Further, the worm 7 was made to have a tooth surface grinding finish using chromium molybdenum steel, and an aluminum / brass based alloy was used as a material of the worm wheel 8. Further, a worm reduction gear having a reduction ratio of 1/60 is used as the auxiliary reduction gear 2, and both the actuator 5 and the auxiliary reduction gear 2 are greased for lubrication. As a result, the overall power transmission efficiency in this embodiment reached about 20%.

  Although the transmission efficiency of about 20% will receive the impression that it is low judging from the numerical value alone, it is high when using a two-step worm gear and considering that it has a self-locking function as a power transmission system. Can. By realizing this high transmission efficiency, it has become possible to manually open and close the valve by manually turning an actuator without an automatic declutch function manually.

  In the present embodiment, since the number of worms 7 is four, the reduction ratio of the actuator 5 is restricted. As a result, it may be difficult to realize the extremely large reduction ratio required to open and close the part-turn valve 1 only by the two-stage worm gear reduction. However, in such a case, a front stage reduction mechanism may be provided between the motor 9 and the worm 7. It is deceleration in the high speed rotation range, and can be easily realized by a small helical gear. Such an arrangement also has a limited impact on cost and space.

  Next, the operation of the present invention will be briefly described. It is assumed that the actuator 5 can not be operated in the electric mode due to a power failure or the like while the actuator 5 is set to the electric mode which is the normal operation mode. In this state, there is no choice but to operate the actuator 5 in the manual mode. However, depending on the location where the valve is installed, it may be difficult for the operator to approach the side of the actuator 5. In consideration of such circumstances, a chain sprocket (not shown) is attached to the manual handle 14 of the actuator 5 so that it can be operated from other than the machine side, and the manual handle can be rotated by a chain hooked to the chain sprocket It has been In addition, an extension shaft may be attached to the shaft center of the manual handle, and the manual handle may be rotated via the extension shaft from a location other than the machine side.

  In the above-described state of the art, the actuator can not be manually operated unless the operator approaches the machine side and operates the manual lever to switch from the electric mode to the manual mode. However, with the actuator 5 according to the present invention, switching from the electric mode to the manual mode is unnecessary, and the part turn valve 1 can be opened and closed simply by turning the manual handle 14. Further, in the size selection of the actuator, since the actuator can be selected on the basis of the driving torque of the valve, it is not necessary to select an actuator larger than necessary. This contributes to the cost reduction of the actuator itself. Furthermore, in the repair work of the existing plant, since it is possible to prevent the actuator from becoming large and increasing the weight, it is not necessary to reinforce the piping line. Therefore, it can also contribute to the reduction of repair costs.

  The motor-operated valve actuator according to the present invention can be applied to a part-turn valve of a plant that requires high operation reliability.

1 part turn valve 2 reducer (auxiliary reducer)
5 actuator 6 output shaft 7 worm 8 worm wheel 9 motor
10 drive sleeve
11 clutch
14 manual handle

Claims (4)

A motor-operated valve actuator mounted on the input side of a reduction gear for driving a part-turn valve and decelerating the rotation of a motor with a worm and a worm wheel to drive the reduction gear,
While the worm gear of the reduction gear has a self-locking function, the worm gear of the motorized valve actuator does not have a self-locking function.
A drive sleeve is provided inside the worm wheel, and an output shaft connected to the reduction gear is provided inside the drive sleeve,
One end of a clutch is provided on the drive sleeve or the output shaft, and a manual handle is provided on the other end of the clutch.
The clutch is disengaged by activation of the motor and brought into connection by deactivation of the motor.
An electric valve actuator characterized in that the valve can be opened and closed only by rotating the manual handle when the motor is stopped.   The motor-operated valve actuator according to claim 1, wherein the number of threads of the worm is two or more and the lead angle is larger than the automatic tightening angle.   The electric valve actuator according to claim 1, wherein an extension shaft is connected to a shaft center of the manual handle.   The motor-operated valve actuator according to claim 1 or 2, wherein the manual handle is provided with a chain sprocket, and the chain is wound around the chain sprocket.

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