JP5191454B2 - Flow control valve - Google Patents

Description

  The present invention relates to a flow control valve whose opening degree is freely increased or decreased by a stepping motor.

  As a conventional flow control valve of this type, for example, a worm is attached to a stepping motor, and the worm wheel is rotated by this worm (for example, see Patent Document 1). In this configuration, the worm wheel is screwed to the fixed side by a screw mechanism, and the worm wheel itself is configured to reciprocate along the rotation axis when the worm wheel rotates. A valve shaft is fixed to the worm wheel, and a valve body is attached to the tip of the valve shaft. Therefore, when the worm wheel reciprocates, the valve body reciprocates together with the valve shaft along with the reciprocation. Since the stepping motor can be stopped at a desired phase, the position of the valve body can be freely changed. Therefore, the flow rate can be controlled by adjusting the opening degree.

Japanese Patent No. 3914053 (FIG. 3)

  Since the stepping motor used in the above-described flow control valve rotates in proportion to the number of input pulses, the position of the valve body can be controlled by the number of input pulses. However, there may be a deviation between the actual phase and the phase that should be originally generated from the number of input pulses. For this reason, in the above flow control valve, the worm wheel is moved to a position where it abuts against the stopper to perform resetting.

  However, a large load is applied to the stepping motor when it comes into contact with the stopper, which increases power consumption. In addition, a large stress is generated in the meshing portion between the worm and the worm wheel, resulting in a problem that the wear becomes severe.

  In view of the above problems, an object of the present invention is to provide a flow control valve capable of correcting the phase of the worm wheel without bringing the worm wheel into contact with the stopper.

In order to solve the above-mentioned problems, the flow control valve according to the present invention has a worm wheel meshed with a worm that is rotated by a stepping motor, the worm wheel is rotated, and the rotary motion of the worm wheel is converted into a linear motion to change the valve body. In the reciprocating flow control valve, the worm wheel is rotatably held so as not to move in the rotational axis direction, and a permanent magnet is attached to the side surface of the worm wheel, and the magnetic detection means is fixed at a position facing the permanent magnet. The rotational phase of the worm wheel can be detected, a spline part is formed at the center of the worm wheel, and a mechanism for converting to the linear motion is connected via the spline part. On the other hand, the thrust force is prevented from acting.

  In the present invention, the rotational phase of the worm wheel is detected in a non-contact manner by the magnetic detection means. In the above conventional one, since the worm wheel moves along the rotation axis, even if a permanent magnet is attached to the worm wheel, the permanent magnet moves together with the worm wheel, so the distance from the magnetic detection means changes, so that the magnetic detection means The magnetism of the permanent magnet could not be detected. In the present invention, by adopting a configuration in which the worm wheel is held so as not to move in the direction of the rotation axis, the interval between the permanent magnet attached to the worm wheel and the magnetic detection means does not change and the magnetic detection is not caused. The rotational phase of the worm wheel can be detected by the means.

  The worm wheel is generally stored in a casing for dust prevention and safety. It is conceivable to attach a magnetic detection means to the outer surface of the casing to detect the magnetism through the wall surface of the casing. However, if the worm wheel and the magnetic detection means are housed in the same casing, the distance from the permanent magnet can be further increased. It can be narrowed, and space saving and reliability improvement can be achieved.

  As is apparent from the above description, the present invention can correct the rotational phase of the worm wheel driven by the stepping motor without bringing the worm wheel into contact with the stopper. In addition, mechanical wear and the like do not increase.

Diagram showing the configuration of the reference example Diagram showing the opened state Diagram showing shape of connecting plate The figure which shows the state which the connecting plate deform | transformed Sectional drawing which shows embodiment of this invention

A configuration which is a premise of the present invention is shown as a reference example in FIGS. Referring to FIG. 1, the flow control valve shown in the figure has a main body 1, and fluid such as water flowing in from an inflow portion 11 provided in the main body 1 is discharged through a valve port portion 13. 12 to flow. A valve body 2 is attached to the valve opening 13 for opening and closing the valve opening 13 and increasing and decreasing the opening degree in the valve opening state.

  The valve body 2 is attached to the lower end of a valve shaft 21 that is long in the vertical direction in the figure. On the other hand, a screw member 22 is attached to the upper end of the valve shaft 21. The screw member 22 is provided with a screw portion 23 on the outer peripheral surface and a pair of detent portions 24 extending downward. The rotation preventing portion 24 is slidably engaged with the main body 1 so as to be slidable in the vertical direction, and prevents the screw member 22 from rotating while allowing the screw member 22 to move in the vertical direction.

  The worm wheel 6 is screwed into the screw portion 23 of the screw member 22. The worm wheel 6 is formed in a double cylindrical shape that is connected to each other, and a screw portion 61 that is screwed into the screw portion 23 is provided on the inner peripheral surface. Further, a worm gear portion 62 is provided on the outer peripheral surface of the worm wheel 6. The worm gear 62 is engaged with a worm 51 fixed to the rotation shaft of the stepping motor 5. When the worm 51 is rotated by the stepping motor 5, the worm wheel 6 is rotated.

  The worm wheel 6 is sandwiched between the holder member 3 and the cover 8 from above and below, and can be rotated about a rotation axis that is long in the up and down direction, but can move in the rotation axis direction, that is, in the up and down direction. Is held so that it cannot. In this embodiment, one permanent magnet 7 is attached to the upper surface of the worm wheel 6 so that the magnetic pole faces upward. A magnetic sensor 71 such as a Hall element was attached so as to face the permanent magnet 7 with a predetermined gap. The magnetic sensor 71 is mounted on a circuit board 72, and is configured to output a detection signal from an output terminal of the circuit board 72 when the permanent magnet 7 is positioned below the magnetic sensor 71. In addition, the main body 1 and the holder member 3 are mutually connected through the connection plate 4 mentioned later.

  With the above configuration, when the worm 51 is rotated by the stepping motor 5 from the state shown in FIG. 1 and the worm wheel 6 is further rotated, the screw member 22 screwed into the screw portion 61 of the worm wheel 6 is prevented from rotating. Moves upward without rotating. Then, the valve body 2 is pulled up together with the valve shaft 21 to which the screw member 22 is attached, and the valve opening 13 is opened. In addition, the state which the valve body 2 was pulled up to the raise end position is shown in FIG.

  The permanent magnet 7 passes a plurality of times below the magnetic sensor 71 until the valve body 2 is pulled up to the position shown in FIG. Then, the position of the stepping motor 5 is corrected from the rotational phase of the worm wheel 6 predicted from the accumulation of the number of pulses input to the stepping motor 5 and the rotational phase when the permanent magnet 7 is positioned below the magnetic sensor 71. can do.

  Incidentally, as shown in FIG. 1, when the outside air temperature decreases in the state where the valve body 2 closes the valve opening 13 as in winter, the water inside the main body 1 may freeze. Since the volume expands when water freezes, the main body 1 and the valve body 2 may be damaged. When such a part is damaged, when the outside air temperature rises and freezing is released, there is a problem that water continues to leak from the inside.

  Therefore, as shown in FIG. 3, the main body 1 and the holder member 3 are connected via the connecting plate 4. That is, connecting bolts are inserted into the connecting plate 4 at four locations, but the connecting plate and the main body 1 are connected by the two bolts 42, and the holder member 3 and the connecting plate 4 are connected by the remaining two bolts 41. And connected. Therefore, the main body 1 and the holder member 3 are not directly connected but are connected via the connecting plate 4.

  Referring to FIG. 4, when the water in main body 1 freezes and the volume expands, connecting plate 4 is deformed and tries to push up holder member 3 upward. As described above, since the main body 1 and the holder member 3 are not directly connected, when the holder member 3 is pushed up, the connecting plate 4 is deformed and the holder member 3 moves upward. A seal 14 is attached between the holder member 3 and the main body 1, but when the holder member 3 moves upward, the seal 14 is detached from the main body 1. Then, since the water in the main body 1 leaks to the outside immediately and the pressure in the main body 1 decreases, the holder member 3 does not move further upward. When the outside air temperature rises, the holder member 3 is slightly pushed back into the main body 1 by the urging force due to the elastic deformation of the deformed connecting plate 4. Then, since the seal 14 seals between the main body 1 and the holder member 3 again, it is possible to avoid a situation in which water in the main body 1 continues to leak.

In the above reference example , the valve shaft 21 is always urged downward by the urging force of the spring 21a. This urging force acts on the worm wheel 6 from the screw portion 23 via the screw portion 61. Therefore, the worm wheel 6 always rotates in a state of being biased downward, and the lower surface of the worm wheel 6 is worn, and the torque for rotating the worm wheel 6 may increase.

Therefore, as shown in FIG. 5, the spline portion 101 is formed on the inner peripheral surface of the worm wheel 100, and the spline portion 91 formed on the outer peripheral surface of the screw member 9 is engaged. By adopting such a configuration, when the worm wheel 100 rotates, the rotational force is transmitted to the screw member 9 via both the spline portions 101 and 91.

  A screw portion 92 is formed on the screw member 9 and is screwed into a screw portion 81 formed on the cover 8. Therefore, when the screw member 9 rotates, the screw member 9 moves up and down to displace the valve shaft 21 and the valve body 2 in the vertical direction.

As described above, since the screw member 9 and the worm wheel 100 have the spline portions 101 and 91 engaged with each other, even if the screw member 9 is moved up and down, the vertical slip between the spline portions 101 and 91 is caused. Thus, the thrust force that is the vertical direction does not act on the worm wheel 100. Therefore, the urging force of the spring 21a does not act on the worm wheel 100, and the worm wheel 100 is not pressed in the vertical direction, so that the rotational torque does not increase.

  In addition, this invention is not limited to an above-described form, You may add a various change in the range which does not deviate from the summary of this invention.

DESCRIPTION OF SYMBOLS 1 Main body 2 Valve body 3 Holder member 4 Connecting plate 5 Stepping motor 6 Worm wheel 7 Permanent magnet 13 Valve opening part 14 Seal 21 Valve shaft 51 Worm 62 Worm gear part 71 Magnetic sensor

Claims (2)

In a flow control valve that meshes a worm wheel with a worm that is rotated by a stepping motor, rotates the worm wheel, converts the rotational movement of the worm wheel into a linear motion, and reciprocates the valve body, the worm wheel is moved in the direction of the axis of rotation. It is configured to be able to detect the rotational phase of the worm wheel by holding it so that it does not move and attaching a permanent magnet to the side of the worm wheel and fixing the magnetic detection means at a position facing this permanent magnet. A spline part is formed at the center of the worm wheel, and a mechanism for converting to the linear motion is connected via the spline part so that a thrust force from the mechanism does not act on the worm wheel. Characteristic flow control valve.   The flow control valve according to claim 1, wherein the worm wheel and the magnetic detection means are housed in the same casing.

Images