JPH0448323Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) The present invention relates to an electro-pneumatic converter.

More specifically, the present invention relates to an automatic-manual changeover switch for an electro-pneumatic converter.

(Prior Art) FIG. 4 is an explanatory diagram of the configuration of a conventional example that has been generally used, and FIG. 5 is an explanatory diagram of the configuration of the main part of FIG. 4.

In the figure, 1 is a torque motor to which an input signal current is input. 11 is a movable piece that is displaced in response to an input signal. Reference numeral 2 denotes a nozzle which is arranged opposite to one end of the movable piece 1 and constitutes a nozzle-flapper mechanism with one end of the movable piece. 3 is a pressure reducing valve 31
This is a control relay to which the supply air pressure Ps is supplied, amplifies the back pressure of the nozzle 2, and outputs the output air pressure Pout. 4 is a feedback bellow provided at the other end of the movable piece 11 and into which the output air pressure Pout of the control relay 3 is introduced. 5 is an automatic-manual changeover switch provided between the nozzle 2 and the control relay 3. The automatic-manual changeover switch 5 is shown in FIG. In Figure 5,
51 is a block, and 52 is a switching chamber provided in the block 51 and having a valve seat 53. The supply air pressure Ps is supplied to the switching chamber 52 via the throttle 54. 55 is a valve body that opens and closes the valve seat 53. 5
51 is an O-ring that seals the switching chamber 52 and the valve body 55. 56 is a communication hole provided between the throttle 54 and the valve seat 53 and connected to the control relay 3. 57 is a connection hole to the nozzle 2 provided on the opposite side of the communication hole 56 across the valve seat 53.

In the above configuration, the automatic-manual switching operation is performed by closing the valve seat 53 with the valve element 55 in the automatic-manual changeover switch 5 to change to the manual operation state, so that the supply pressure Ps to the changeover switch 5 is This becomes the signal pressure to the control relay 3. Therefore, by manually operating the pressure reducing valve 31, the output pressure of the control relay 3 can be manually operated. Next, in order to enter the automatic operation state, the valve seat 53 is opened by separating the valve body 55 from the valve seat 53.
6 becomes the signal pressure to the control relay 3. The device is therefore in automatic operation.

(Problems to be solved by the invention) However, in such a device, an air circuit for switching must be made in the block 51. In addition, consideration must be given to sealing properties and the like. In addition, since the valve seat for switching is located inside the block, it is impossible to visually observe the presence of dust or the like. Since sealing performance must be ensured against movement of the valve body 55, a sealing element such as O
The valve body 55 must be moved against the friction of the ring, etc., and a relatively large force is required to move the valve body 55.

The present invention solves these problems.

An object of the present invention is to provide an inexpensive electro-pneumatic converter that has a simple configuration, is easy to perform automatic-manual switching operation, and is easy to maintain.

(Means for Solving the Problem) In order to achieve this objective, the present invention provides a drive that drives a flapper in response to the input current in an electro-pneumatic converter that controls the air output in response to the input current. means, a nozzle constituting a nozzle flapper mechanism provided opposite to one end of the flapper, a control relay for amplifying the back pressure of the nozzle and outputting it as output air pressure, and a pressure equal to the output air pressure of the control relay. a feedback bellow to which a signal is input; a feedback means for feeding back a force signal of the feedback bellow to the input side of the driving means; The electro-pneumatic converter is provided with a switching lever that opens and closes between the flapper and the nozzle to switch the output air pressure to a manual state.

(Function) In the above configuration, in order to perform an automatic-manual switching operation, in the automatic state, the switching lever does not press the movable piece and the movable piece is not restrained, so the device performs automatic operation. To switch to the manual state, move the switching lever and press the movable piece to close the space between the movable piece and the nozzle. Alternatively, if you use a reverse action control relay, there will be a large
open, so that the nozzle back pressure is the same as the supply air pressure, or, if the gap is open, the same as atmospheric pressure. Thus, the device can be manually operated by manually moving the pressure reducing valve.

Examples will be described in detail below.

(Embodiment) FIG. 1 is an explanatory diagram of the main part configuration of an embodiment of the present invention.

In the figure, the same symbols as in FIG. 4 indicate the same functions.

Hereinafter, only the differences from FIG. 4 will be explained.

6 is a changeover switch. The changeover switch 6 has a changeover lever 61 and a lever fulcrum 62. The switching lever 61 is disposed opposite to the other end of the movable piece 11, and when switching to the manual state, presses the movable piece 11 to close the gap between it and the nozzle 2, and has a bifurcated tip. The switching lever 61 rotates around a lever fulcrum 62.

In the above configuration, in the automatic state, the switching lever 61 is in a neutral position, and the other end of the movable piece 11 is not restrained.

In the manual state, by rotating the switching lever 61, the other end of the movable piece 11 is pressed against the nozzle 2, and the nozzle back pressure increases to the supply pressure Ps. Therefore, the supply pressure circuit and the output pressure circuit of the control relay 3 are always in a conductive state, and a desired output pressure can be obtained by manually operating the pressure reducing valve 31.

As a result, it is possible to obtain a device that can easily switch between automatic and manual states by rotating the switching lever 61.

In this case, by rotating the switching lever 61, the gap between the movable piece 11 and the nozzle 2 is opened and closed to enable automatic-manual switching, so that automatic-manual switching can be performed as in the conventional example shown in FIG. There is no need to create a separate air circuit for the block. Furthermore, there is no need to take into account sealing properties and the like. Furthermore, since the valve seat for switching is located in the block, there is no disadvantage that dirt cannot be visually observed. In addition, unlike the conventional example shown in FIG. 4, the valve body must be moved while ensuring sealing performance, so there is no disadvantage of requiring a large force, and the switching lever 61 can be easily moved using an actuator such as a bellows or solenoid. It can be rotated and remote control can be easily adopted.

In addition, in a reverse operation control relay in which the output pressure decreases due to an increase in nozzle back pressure, which is input to the control relay, the switching lever 61 is used to move the movable piece 11 away from the nozzle 2, thereby switching between automatic and manual operation. A switching action is obtained.

Furthermore, although the switching lever 61 has been described as having a bifurcated tip, it is needless to say that it does not have to be bifurcated.

FIG. 2 is a block diagram of another embodiment of the present invention.

In this embodiment, the flapper is electrically driven by a driving means 73. On the other hand, the force of the feedback bellows 4 is electrically detected and this detection signal is fed back to the input side of the drive means.

In the figure, 71 is a current-voltage converter that converts the input current signal Io into a voltage, 72 is an amplifier that amplifies the voltage from the current-voltage converter 71, and 73 is a drive that drives the flapper 11 with the voltage output from the amplifier 72. In this case, as shown in FIG. 3, a piezoelectric actuator made of a piezoelectric element is used. 74 is a nozzle flapper mechanism, 5 is an automatic/manual/emergency exhaust switching switch, and 3 is a control relay 4 is a feedback bellow. 7
Reference numeral 5 denotes a force/electrical signal converter that converts the force of the feedback bellows 4 into an electrical signal and feeds it back to the input side of the amplifier 72.

(Effects of the Invention) As explained above, the present invention provides an electro-pneumatic converter that controls air output in accordance with an input current, including a driving means for driving a flapper in response to an input current, and one end of the flapper. a nozzle that is provided opposite to and constitutes a nozzle flapper mechanism;
A control relay that amplifies the back pressure of the nozzle and outputs it as output air pressure, a feedback bellow that receives the same pressure as the output air pressure of the control relay, and a feedback bellow that transmits the force signal of the feedback bellow to the drive means. Feedback means for providing feedback to the input side; and a switching lever that is arranged opposite to one end of the flapper and presses the flapper when necessary to open and close the gap between the flapper and the nozzle to switch the output air pressure to a manual state. By rotating the switching lever, the movable piece is pressed and the gap between the movable piece and the nozzle is opened and closed to automatically adjust the output air pressure Pout of the device. Manual switching is possible.

As a result, there is no need to create a separate air circuit for automatic/manual switching as in the prior art. Furthermore, there is no need to take into account sealing properties and the like. Furthermore, since the valve seat for switching is located in the block, there is no disadvantage that dirt cannot be visually observed. In addition, there is no disadvantage of requiring a large force to move the valve body while ensuring sealing performance, as in the conventional example, and remote control can be easily adopted even with bellows, etc., which generate only a small force. I can do it.

Therefore, according to the present invention, it is possible to realize an inexpensive electro-pneumatic converter with a simple configuration, easy automatic-manual switching operation and easy maintenance.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the main part configuration of an embodiment of the present invention,
FIG. 2 is a block diagram of another embodiment of the present invention;
FIG. 3 is an explanatory diagram of the main part configuration of FIG. 2, and FIG. 4 is an explanatory diagram of the configuration of a conventional example commonly used.
FIG. 5 is an explanatory diagram of the main part configuration of FIG. 4. 1... Torque motor, 11... Movable piece, 2...
Nozzle, 3... Control relay, 31... Pressure reducing valve, 4... Feedback bellow, 6... Changeover switch, 61... Changeover lever, 62... Lever fulcrum, 71... Current-voltage converter, 72 ...Amplifier, 73...Driving means, 74...Nozzle flapper mechanism, 75...Force-electrical signal converter.

Claims (1)

[Scope of utility model registration request] An electro-pneumatic converter that controls air output in accordance with an input current, comprising: a drive means for driving a flapper in response to an input current; a nozzle provided opposite to one end of the flapper and forming a nozzle flapper mechanism; , a control relay that amplifies the back pressure of the nozzle and outputs it as output air pressure, a feedback bellow to which the same pressure as the output air pressure of the control relay is input, and a force signal of the feedback bellow that is transmitted to the driving means. a feedback means for providing feedback to the input side of the flapper; and a switching device disposed opposite to one end of the flapper, which presses the flapper when necessary to open and close the gap between the flapper and the nozzle to switch the output air pressure to a manual state. An electro-pneumatic converter equipped with a lever.