JPH0680355B2 - Switching device for valve actuator - Google Patents

Description

TECHNICAL FIELD The present invention relates to a switching device that is used by being attached to a valve opening / closing actuator.

[Prior Art] In various plants, firefighting equipment, and the like, valve actuators in which valves are opened and closed by power of a motor or the like are widely used. In a general valve actuator, a worm wheel is mounted on the output shaft, the worm is meshed with the worm wheel, and the worm is driven by a motor to rotate the output shaft. There is. Then, the valve shaft of the valve to be operated is opened and closed by using this output shaft.

By the way, when operating this kind of valve actuator by remote control or automatic control, information on the set limit operating position of the valve actuator, that is, whether the output shaft (valve body) has reached a preset limit position or not. Or information regarding a set limit torque, that is, information regarding whether or not a torque equal to or more than a preset limit torque value is acting on the output shaft due to seating of the valve element or the like is sequentially collected and fed back. Is essential. Therefore, in such a valve actuator, a position limit switch mechanism configured to switch the position limit switch and output a signal to that effect when the set limit operating position is reached and the set limit torque value are exceeded. In this case, a switching device having a torque limit switch mechanism configured to switch the torque limit switch and output a signal to that effect is generally attached.

By the way, a conventional switching device of this type is, for example,
As shown in JP-B-49-4421, a feed screw type is used as the position limit switch mechanism. That is, the conventional position limit switch mechanism includes a threaded rod that rotates in synchronization with the output shaft of the valve actuator body, and a guide rod that is arranged parallel to the threaded rod and is rotatable in parallel around the axis of the threaded rod. A spring that elastically supports the guide rod in a neutral position, a nut screwed to the screw portion and one end of which is slidably engaged with the guide rod to prevent rotation, and a screw forward and backward movement of the nut. And a stopper for locking at a predetermined position. However, when the screw rod is further rotated in the same direction while the nut is in contact with the stopper, the nut and the screw rod act together with the guide rod while resisting the biasing force of the spring. Since it rotates, the position limit switch is switched using this rotation operation.
Therefore, the position where the position limit switch is switched by adjusting the position of the stopper, that is, the setting limit position described above can be appropriately moved and adjusted.

[Problems to be Solved by the Invention] However, in the case of the above-mentioned configuration, inconvenience occurs when the valve actuator is manually operated while the motor is stopped. That is, when the output shaft is further manually rotated beyond the set limit position, the screw rod, the nut, and the guide rod try to rotate further beyond the required rotation angle. There is a possibility that the switch pusher that is rotated by being urged, the limit switch that is pressed by the switch pusher to switch, and the like are destroyed. Therefore, in the conventional art, a slip clutch is provided between the input shaft of the switching device and the screw rod, and when a torque of a predetermined value or more is applied to the input shaft, the input shaft and the It is designed to prevent damage to switches etc. by causing slippage with the screw rod. However, if you do this
Each time the output shaft is erroneously operated beyond the set limit position during manual operation to the overstroke side, there is a problem that a positional deviation occurs between the input shaft and the threaded rod, and readjustment becomes necessary.

The present invention aims to solve such problems easily and reliably.

[Means for Solving the Problems] In order to achieve the above object, the present invention converts the change of the operating position of the output shaft into an intermittent counting operation by the position limit switch mechanism. A counter gear row that intermittently operates the intermittent rotation shaft that is finally provided when the output shaft rotates to the set limit position, and the intermittent rotation shaft when the intermittent rotation shaft intermittently rotates from the standby position to the operating position. The counter includes a switch pusher that is biased by a rotary shaft to rotate, and a position limit switch that is biased by the pusher to switch when the switch pusher rotates. The gear train is rotatable in conjunction with the output shaft and is arranged in parallel with the intermittent rotation shaft, and the frontmost main gear unit and the rotatable shaft which are integrally rotatably mounted on the adjustment shaft. Multiple mays mounted on A first gear unit, a sub gear unit or a plurality of sub gear units that are rotatably mounted on the intermittent rotation shaft, and a final stage sub gear unit that is integrally rotatable. It is characterized in that the rotational forces transmitted to the frontmost sub gear unit are meshed with each other so as to be decelerated and transmitted to the final sub gear unit through the final main gear unit.

[Operation] According to such means, the intermittent rotation shaft provided at the final stage of the counter gear row performs one intermittent operation at the stage when the output shaft of the valve actuator body is rotated to the set limit position, and the position limit is achieved. Although the switch is switched, even if the output shaft is further operated beyond the set limit position to the overstroke side, the above-mentioned inconvenience does not occur for some reason. That is, when the switch pusher is driven by using the row of gears in this way, after the output shaft reaches the set limit position and the intermittent rotation shaft intermittently operates, this output shaft is further connected to the valve actuator. The intermittent rotation shaft will not operate in the same direction again unless the overstroke is made as large as one stroke. Therefore, in normal use, no inconvenience due to overstroke can occur.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a switching device 2 according to the present invention is attached to an actuator body 1.

As shown schematically in FIG. 1, the actuator body 1 has a worm wheel 4 mounted on an output shaft 3 and has a worm 5 meshed with the worm wheel 4, and the worm 5 is driven by a motor (not shown). The output shaft 3 can be rotated by driving. Then, the rotation of the output shaft 3 is used to open and close the valve body (not shown) of the valve, which is the operation target. In addition, the support shaft 6 of the worm 5
Is held slidably in the axial direction, and is converged and biased to a fixed position by a disc spring or the like (not shown).
The elastic deviation amount of the support shaft 6 in the axial direction is taken out as a torque signal via the shaft 6a. Further, the rotation position of the output shaft 3 is taken out as a position signal through the worm 7 and the worm wheel 8 meshed with the worm 7, and the input shaft 9 of the switching device 2 is taken out.
I am trying to type in.

As shown in FIG. 1, the switching device 2 includes a torque limit switch mechanism 11 that is actuated by a common frame 10 by being actuated by the torque signal, and a position limit switch mechanism 12 that is actuated by being actuated by the position signal. It is a combination of and.

As shown in FIG. 1, FIG. 3, and FIG. 10, the torque limit switch mechanism 11 is provided by penetrating the front plate 13 and the rear plate 14 of the frame 10 and can rotate forward and backward about the axis. The rotary shaft 15, the switch pusher 16 rotatably mounted on the front half of the rotary shaft 15, the torque limit switches 17 arranged on both sides of the switch pusher 16, and the forward / backward movement shaft of the valve actuator body 1. 6a forward / backward movement is performed on the rotary shaft 15
And a second motion conversion mechanism 19 for converting the normal / reverse rotation motion of the rotary shaft 15 into the switch pressing motion of the presser 16. Become. The first motion conversion mechanism 18 is mainly composed of a cylindrical body 21 fixed to the rear end of the rotary shaft 15 so as to be integrally rotatable.
As shown in FIGS. 1 and 10, the cylindrical body 21 is a cylindrical body having a front end fixed to the rotary shaft 15 via a pin 22, and has a spiral cam groove paired on the outer periphery thereof. The slide pin 24 is penetrated through the cam groove 23.
Then, both ends of the slide pin 24 are slidably engaged with an axial groove 26 provided in the base body 25 of the frame 10, and the advancing / retreating shaft 6a is attached to the slide pin 24 on the rear end side of the tubular body 21. It is fitted so as to abut. Reference numeral 25 is a spring that urges the cylindrical body 21 to rotate in the arrow X direction. In addition, the second motion conversion mechanism 19,
As shown in FIGS. 1 and 3, a rotary plate 28 mounted on the front end of the rotary shaft 15 so as to be synchronously rotatable, a pair of cam bodies 29 axially attached to the rotary plate 28, and The switch pusher 16 is provided with a protrusion 31 projecting from the front end face between the two cam bodies 29, and when any one of the cam bodies 29 rotates when the rotary shaft 15 rotates by a set angle or more. The protrusion 31 can be pressed to rotate the switch pusher 16 to a position where any one of the limit switches 17 is switched. Each of the cam bodies 29 has a shape in which the diameter thereof gradually changes in the rotation direction, and as shown in FIG.
An adjusting knob in which the fixed position of 29 is arranged on the front surface of the rotary plate 28.
It can be changed by rotating 32. Then, when the fixed position of the cam body 29 is changed, the position where the cam body 29 and the protrusion 31 contact each other can be changed, and the set limit torque value can be adjusted. In this embodiment, the cam body 29 can be set at a position where the cam body 29 cannot come into contact with the protrusion 31 at all.

On the other hand, as shown in FIGS. 1 and 4, the position limit switch mechanism 12 converts the input shaft 9 and the rotation of the input shaft 9 into an intermittent counting operation to provide an intermittent rotation provided at the final stage. A pair of counter gears 35 for intermittently rotating the cam bodies 34 of the shafts 44 and when these cam bodies 34 intermittently rotate from a standby position a shown by a solid line in FIG. 4 to an operating position b shown by an imaginary line. And a pair of switch pushers 36 that are biased by the cam body 34 to rotate, and two pairs of position limits that are biased by the pushers 36 to switch when the switch pushers 36 rotate. And a switch 37. More specifically, the input shaft 9 is rotatably held by the boss portion 25a of the base 25 of the frame 10, and the support shaft 41 of the worm wheel 8 is connected to the rear end of the input shaft 9. In addition, the counter row 35
As shown in FIGS. 6 to 9, three sets of main gear units 43 ₁ , 43 ₂ , 43 ₃ are mounted on the adjusting shaft 42, and are mounted on the intermittent rotation shaft 44. Main gear unit 43 ₁ , 4
3 sets of sub gear units 45 ₁ , 45 ₂ , 4 which engage with 3 ₂ , 43 _3.
It consists of 5 and ₃ . Each main gear unit 43 ₁ , 4
3 _2, 43 _3, as shown in FIG. 7-Fig. 9, for example, the first gears 46 having teeth 46a of 20 the entire circumference, the first gears 46
The second gear 47 having the same outer diameter as the above and having a single valley portion 47a
And two teeth that have the same root diameter as the root diameter of the second gear 47.
The third gear 48 having only 48a is integrated by aligning the axes. Incidentally, only the main gears unit 43 ₁ at the first stage is fixed to the adjusting shaft 42, the other main gears unit 43 _2, 43 ₃ are then rotatably supported relative to the adjusting shaft 42. In addition, each of the sub gear units
Similarly, as shown in FIGS. 7 to 9, 45 ₁ , 45 ₂ and 45 ₃ are formed by removing every other tooth from a standard gear having eight teeth and the second gear 47. The first small gear 51 arranged at a position corresponding to the first small gear 52, the second small gear 52 having eight teeth and arranged at a position corresponding to the third gear 48, and the same second small gear 52. The third small gear 53, which has a shape and meshes with the first gear 46 of the main gear unit of the next stage, is integrated with its axial center aligned. Only the last sub gear unit 45 ₃ is fixed to the intermittent rotation shaft 46, and the other sub gear units 45 ₁ and 45 ₂ are the intermittent rotation shafts.
It is rotatably supported with respect to 46. Also, each adjustment axis
A manual operation portion 42a for engaging an adjustment tool such as a driver is provided at the tip of the 42, and these adjustment shafts 42 can be manually rotated. Then, between the input shaft 9 and the counter gear train 35, a power connection / disconnection mechanism for disconnecting the input shaft 9 and each counter gear train 35 only when the adjustment shaft 42 is manually operated. 55 is provided. As shown in FIGS. 1 and 10, the power connection / disconnection mechanism 55 includes a cylindrical portion 56 integrally formed at the front end portion of the input shaft 9 and having a pair of axial grooves 56a, and the cylindrical portion 56. A transmission shaft 58 having a rear end portion slidably fitted therein and a front end portion slidably penetrating the intermediate plate 57, and the counter gear row 35 formed integrally with the intermediate portion of the transmission shaft 58. A transmission gear 59 that meshes with the first gear 46 at the frontmost stage and a rear end portion of the transmission shaft 58 that is penetrated and has both ends thereof formed into the cylindrical portion.
A transmission pin 61 slidably guided in the groove 56a of 56,
An operation shaft 63 slidably inserted in a fixed guide tube 62 fixed to the front plate 13 and arranged in front of the transmission shaft 58 with their axes aligned, and both ends of the operation shaft 63 which are penetrated by the operation shaft 63. A locking pin 64 whose part is engaged with the groove 62a of the fixed guide tube 62,
A spring 65 that biases the transmission shaft 58 forward and a spring 66 that biases the operation shaft 63 forward are provided.

Reference numeral 67 is a spring that biases the two switch pressing elements 36 in a direction away from the corresponding limit switch 37.

With such a configuration, when the valve actuator 1 is fully closed or fully opened and the torque acting on the output shaft 3 increases, the support shaft 6 of the worm 5 elastically supports a disc spring or the like (not shown). It moves forward or backward in the axial direction against the force, and the forward / backward movement is input to the torque limit switch mechanism 11 of the switching mounting 2 via the forward / backward shaft 6a. That is, when the advancing / retreating axis 6a moves back and forth in the axial direction,
The forward / backward movement is converted into forward / reverse rotation of the cylinder 21 and the rotary shaft 15 by the cooperation of the pin 24 guided by the axial groove 26 and the spiral groove 23. Then, when the rotary shaft 15 rotates forward and backward, the turntable 28 turns correspondingly together with the cam body 29. Therefore, when the torque acting on the output shaft 3 becomes large,
The turning angle of the turntable 28 increases, and one of the cam bodies 29 pushes the projection 31 to tilt the switch pusher 16,
Switch one of the limit switches 17. Therefore, when the operation knob 32 is rotated, the cam body 29 moves to the projection 31.
If the torque of the output shaft 3 reaches the desired set limit torque value, the limit switch
It is possible to switch 17 to stop the motor of the valve actuator 1.

When the output shaft 3 rotates, the operating position of the valve element changes, but the amount of change in the operating position is continuously transmitted to the input shaft 9 of the position limit switch mechanism 12 via the shaft 41. Then, when the input shaft 9 rotates, its rotational power is transmitted to the frontmost stage of each counter gear row 35 via the transmission gear 59,
These counter gear rows 35 perform counting operations. That is, each time the main gears unit 43 ₁ of the preceding stage is rotated once, in other words, the second gears 47 of the main gears unit 43 ₁
Troughs 47a and the third every two consisting teeth 48a intermittently urging portion 43 ₁ a of the gears 48 passes through the position facing the sub-gears unit 45 ₁ of the previous stage, the sub-gears unit 45 ₁ 2 teeth It is rotated intermittently for a minute (90 ° in this embodiment). When the sub gear unit 45 ₁ is intermittently rotated by _one , the middle main gear unit 43 ₂ meshing with the third small gear 53 of the sub gear unit 45 ₁ is rotated by two teeth. In this way, the main gear unit 43 ₂ in the middle stage rotates intermittently, but at this stage as well, the sub gear unit in the middle stage is rotated 90 times every time the main gear unit 43 ₂ in the middle stage makes one rotation, as described above. Rotate intermittently by ° C. Then, it is accompanied, subsequent main gears unit 43 ₃ 2 tooth at a time intermittently rotated. Then, the sub-gears unit 45 ₃ is rotated 90 ° intermittently at the stage of the intermittent urging portion 43 ₃ a of the subsequent main gears unit 43 ₃ is passed through the sub-gears unit 45 ₃ in the subsequent stage, it is accompanied, intermittent times The moving shaft 44 and the cam body 34 fixed to the moving shaft 44 rotate from the standby position a to the operating position b. When the cam body 34 rotates to the operating position b, the leg portion 36a of the switch pusher 36 is pushed by the cam body 34, and the switch pusher 36 rotates as shown by the imaginary line in FIG. And the limit switch 37 is switched. In this case, when the input shaft 9 is rotated in the reverse direction, the cam body 34 immediately returns to the standby position a, and the pressing of the limit switch 37 by the switch pressing element 36 is released.

By the way, in order to accurately switch the limit switch 37 between the fully closed position and the fully open position of the valve, the position at which the cam body 34 operates needs to be adjusted in advance. The adjustment for that is performed as follows. First,
At all times, as shown in FIG. 1 and FIG. 10, the locking pin 64 of the power interrupting mechanism 55 is present in the groove 62a of the fixed guide tube 62, and the transmission gear 59 is the main gear of the counter gear train 35. It is meshed with gear unit 43 ₁ . From this state, the operating axis 63
Press the tip of the from the front side. Then, this operation axis
63 pushed to slide transmission shaft 58 rearward relative to the input shaft 9, together with the transmission gears 59 are disengaged from the main gears unit 43 _1, the locking pin 64 of the operating shaft 63 is a groove 62a
Get out. When the operating shaft 63 is rotated and the pressing is stopped in this state, both ends of the locking pin 64 of the operating shaft 63 are locked to the rear end surface 62b of the fixed guide tube 62 so that the operating shaft 63 and the transmission The shaft 58 is held in the retracted position, and the input shaft 9 and the counter gear rows 35 remain separated. Thus, in this state, the switching position of the limit switch 37 can be adjusted by appropriately rotating the adjustment shaft 42 of each counter gear row 35. After finishing the adjustment in this way, when the operating shaft 63 is rotated, the locking pin 64 of the operating shaft 63 is fitted into the groove 62a again, and the operating shaft 63 is moved forward by the biasing force of the spring 66. Project. As a result, the transmission shaft 58 is pressed by the spring 65 and returns to the front, and the transmission gear 59 returns to its original position.
Meshes with the first gear 46 of.

As described above, when the output shaft 3 of the actuator body 1 is applied with a torque equal to or greater than the set limit torque value, and when the operating position of the output shaft 3 reaches the set limit position, the corresponding limit switches are respectively provided. It is possible to switch between 17 and 37 and feed back a signal to that effect to a control circuit or the like, but in this device, a counter gear type is used as the position limit switch mechanism 12. Therefore, after the output shaft 3 reaches the set limit position and the cam body 34 of the intermittent rotation shaft 46 performs one intermittent operation, the output shaft 3
In addition, the settable speed of the valve actuator is 1 /
The cam body 34 will not operate again in the same direction unless the overstroke is made as large as four strokes.
Therefore, even if the output shaft 3 is overstroked beyond the limit setting position by a manual operation or the like, an unreasonable force acts on the switch pusher 36 or the limit switch 37, or the input shaft 9 and the reduction mechanism. (Counter gear row 3
5) There will be no problems such as a gap between the position and 5) and readjustment.

The structure of the power connecting / disconnecting mechanism provided between the input shaft and the counter gear train is not limited to that described above, and various modifications can be made without departing from the spirit of the present invention.

Further, the counter gear row is not limited to three rows, and may be two rows or four or more rows.

Further, it goes without saying that the switch pusher of the position limit switch mechanism and the switch pusher of the torque limit switch mechanism do not have to be provided on the common shaft. The advantage that the mechanism can be compactly unitized is obtained.

EFFECTS OF THE INVENTION Since the present invention is configured as described above, even if the output shaft of the valve actuator main body is overstroked by a manual operation or the like beyond the set limit position, each part is overloaded or readjusted. It is possible to provide an excellent switching device for a valve actuator without the inconvenience of requiring work.

[Brief description of drawings]

The drawings show one embodiment of the present invention, FIG. 1 is a sectional view showing the whole, FIG. 2 is a view taken in the direction of arrow A in FIG. 1, and FIG.
FIG. 4 is a sectional view taken along line BB in FIG. 4, and C in FIG.
-C line sectional view, FIG. 5 is a DD line sectional view in FIG. 1, FIG. 6 is an enlarged view showing a counter gear row, and FIG. 7 is an EE line sectional view in FIG. 6 is a sectional view taken along line FF in FIG. 6, FIG. 9 is a sectional view taken along line GG in FIG. 6, and FIG. 10 is a partial perspective view. 1 …… Actuator body 2 …… Switching device 3 …… Output shaft 9 …… Input shaft 11 …… Torque limit switch mechanism 12 …… Position limit switch mechanism 15 …… Axis (rotating shaft) 16 …… Switch pusher 17… … Limit switch 35 …… Counter gear row 36 …… Switch pusher 37 …… Limit switch

Claims (2)

[Claims] 1. A torque limit switch mechanism for detecting whether or not a torque acting on an output shaft of a valve actuator body has reached a set limit torque value, and whether or not an operating position of the output shaft has reached a set limit position. A switching device for a valve actuator, comprising a position limit switch mechanism for detecting whether or not the position limit switch mechanism converts a change in the operating position of the output shaft into a count operation, and the output shaft is set by the position limit switch mechanism. A counter gear row that intermittently operates the intermittent rotation shaft that is finally provided at the stage of rotating to the limit position, a switch pusher that is rotated by being biased by the intermittent rotation shaft of the counter gear row, and this switch. A limit switch that is urged by the pusher to switch when the pusher rotates, and the counter gear train is interlocked with the output shaft. Adjustment shaft that is rotatable in parallel with the intermittent rotation shaft, the front stage main gear unit that is integrally rotatably mounted on the adjustment shaft, and a plurality of rotatably mounted main gear units. A unit, one or a plurality of sub gear units rotatably mounted on the intermittent rotation shaft, and a final stage sub gear unit which is integrally rotatably mounted, and includes a front stage main gear unit to a front stage. A switching device for a valve actuator, wherein the rotational force transmitted to the sub gear unit is meshed with each other so that the rotational force is transmitted to the final sub gear unit through the final main gear unit in a reduced speed. 2. The valve actuator switching device according to claim 1, wherein the switch pusher is supported on a shaft common to the switch pusher of the torque limit switch mechanism.