JPH0750419B2 - Pressure reducing valve - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure reducing valve used in a pneumatic or hydraulic system, and in particular, outputs a confirmation signal for the pressure reducing valve itself when the secondary side pressure reaches a set pressure value. It was devised to do so.

(Prior Art) A pneumatic or hydraulic system is usually provided with a pressure reducing valve (regulator) for constant control of the pneumatic or hydraulic pressure.

In FIG. 3, the compressed air pressure source 100, the air filter 102, the source pressure valve 104, the lubricator 106, the direction switching valve 108, the speed controllers 110 and 112, and the air cylinder 114 constitute a typical pneumatic system.

The resistance welding machine 120 uses this pneumatic system as a pressurizing means. The material to be welded 124, 126 has a pair of electrodes 128, 1
A predetermined pressure is applied by the air cylinder 114 via 30 and a welding current is supplied from the power supply circuit 134. 122 is a pressing force transmission mechanism, and 132 is a fixed part.

The amount of pressure applied to the materials to be welded 124, 126 is the cylinder 114
Depends on the pressure of the compressed air supplied to the
It is specified at a secondary pressure of 104. The pressure on the secondary side of the pressure reducing valve 104 can be adjusted, and a pointer is displayed on the pressure gauge 105. Therefore, by setting the secondary pressure of the pressure reducing valve 104, it is possible to set the pressure applied to the materials to be welded 124, 126.

Then, in the resistance welding machine 120 as described above, since the energization is started when the applied pressure reaches the set value, the timing when the secondary side pressure of the pressure reducing valve 104 actually reaches the set pressure value is set. It is necessary to know, and as a means for that, a pressure switch 107 is provided on the secondary side of the pressure reducing valve 104.
This pressure switch 107 has, for example, a piston and a micro switch, and the piston bends a spring by the input air pressure, and when the input air pressure reaches a set pressure value, the button of the micro switch is pressed down to output an electric signal. It is like this. This electric signal is given to the power supply circuit 134 as a set pressure confirmation signal.

Such a pressure switch is used not only in the resistance welding machine described above, but also in various devices and systems as safety confirmation means or sequence control means.

(Problems to be Solved by the Invention) However, when the pressure reducing valve and the pressure switch are arranged in parallel as described above, there are the following disadvantages. That is, the set pressure value of the pressure switch must be changed every time the set pressure value of the pressure reducing valve is changed, and the pressure adjusting work is very troublesome. In addition, the pressure switch may often forget to adjust the pressure, in which case the system will malfunction, and in the case of the resistance welding machine as described above, energization under an undesired pressure will occur. If done, the welding quality may be deteriorated.

The present invention has been made in view of the above problems, and in order to eliminate the need for a special (individual) pressure switch, a confirmation signal is output by itself when the secondary pressure reaches a set pressure value. The purpose is to provide a pressure reducing valve.

(Means for Solving the Problems) In order to achieve the above object, the pressure reducing valve of the present invention includes a pressure adjusting spring for setting the secondary pressure and a first pressure receiving spring for receiving the pressure from the spring. A pressure balance means that has a surface and a second surface that receives the secondary pressure, and that is displaced in accordance with the pressures respectively received by the first and second surfaces;
A valve body that is interlocked with the pressure balancing means; a valve seat that contacts the valve body when the secondary side pressure exceeds a set pressure value to shut off the primary side and the secondary side; the valve body and the valve; Position sensor means for detecting the position of the pressure balance means when it comes into contact with the seat and outputting an electrical set pressure confirmation signal is provided.

(Operation) When the secondary side pressure is lower than the set pressure value, the balancing means (for example, diaphragm) is displaced against the pressing force of the pressure adjusting spring, so that the valve element separates from the valve seat and passes through the gap. Fluid (for example, compressed air) is sent from the primary side to the secondary side. As a result, the secondary pressure gradually increases, and accordingly, the balancing means is displaced in the direction against the secondary pressure, and the valve body also approaches the valve seat. And
When the secondary side pressure reaches the set pressure value and the valve body comes into contact with the valve seat and the primary side and the secondary side are shut off, the position of the pressure balancing means reaches the predetermined position and the position sensor means Responds by outputting an electrical set pressure confirmation signal. Upon receiving this set pressure confirmation signal, the external device can start a predetermined step. In the present invention, since the confirmation signal is output at a constant movable pair position with respect to an arbitrary set pressurization value, it is necessary to perform pressure adjustment for confirmation signal generation when changing the set pressurization value of the secondary pressure. There is no.

(Embodiment) A preferred embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

Embodiment 1 FIG. 1 shows the structure of a direct acting pressure reducing valve according to the first embodiment.

A pressure adjusting spring 12 is arranged in the bonnet 10, and a pressure adjusting screw is attached to a receiving plate 14 fixed to the upper end of the spring 12.
The lower end of 16 is in pressure contact, and the lower end of the pressure adjusting spring 12 is in pressure contact with the upper surface of the hub 20 fixed to the center of the diaphragm 18. As a result, a pressing force corresponding to the amount of deflection of the spring 12 is applied to the upper surface of the diaphragm 18. And
This pressing force can be variably adjusted by turning the pressure adjusting screw 16.For example, turning the screw 16 clockwise increases the pressing force, and conversely turning the screw 16 counterclockwise decreases the pressing force. The pressure of the secondary pressure can be adjusted.

The lower surface of the diaphragm 18 faces the chamber 22, and the chamber 22 receives the secondary side compressed air from the secondary side OUT port 28 through the passage 24. As a result, the diaphragm 18 receives the set pressure by the pressure adjusting spring 12 on its upper surface and the secondary side pressure on its lower surface, and moves up and down so as to balance these two pressures.

A relief valve 32 is formed at a lower end of a relief hole 30 provided at the center of the hub 20, and an upper end of a valve stem 34 is pressed against the relief valve 32. The intermediate portion of the valve stem 34 is fixed to the valve body 36. The valve body 36 is supported by a valve spring 38, and its upper surface faces a valve seat 40 formed on the valve body.
Then, when the secondary pressure is lower than the set pressure, the diaphragm 18 is pushed down and the valve body 36 and the valve seat are
There is a gap in 40, through which the primary side compressed air is sent from the IN port 26 on the primary side to the secondary side. Then, when the secondary side pressure becomes equal to or higher than the set pressure value, the diaphragm 18 is pushed upward and the valve body 36 comes into contact with the valve seat 40 to shut off the primary side and the secondary side. In addition, 44 is a through hole to the atmosphere, and 46 is an O-ring.

The above-mentioned structure is common to the conventional one, and the characteristic part of this embodiment will be described below.

In this embodiment, as shown in FIG.
A sensor box 50 is attached to the bottom of 42,
An opening 42a is formed in the center of the valve pressing lid 42, and a lower end 34a of the valve stem 34 extends inside the box 50 through the opening 42a. And, this valve stem lower end portion 34a
A non-contact type position sensor 52 is attached to the box 50 close to the box.

The position sensor 52 may be a commercially available proximity switch or photoelectric switch. For magnetic proximity switches,
The valve stem 34 is made of magnetic metal and has a proximity switch 52.
Magnetically detects the position of the valve stem lower end portion 34a.
In the case of a photoelectric switch, the valve stem lower end portion 34a may be a light-reflecting material, and the photoelectric switch 52 has a light emitting element and a light receiving element, and position detection is performed based on the light reflected by the valve stem lower end portion 34a. To do. Whichever type of position sensor is used, when the valve body 36 comes into contact with the valve seat 40, the valve stem lower end portion 34a reaches a position at a certain detection distance from the proximity switch 52, and the proximity switch 52 operates there. It is configured to output an electrical signal.

Therefore, when the secondary pressure is set to an arbitrary pressure value by turning the pressure adjusting screw 16, a confirmation signal is given at a predetermined timing (that is, the timing when the secondary pressure reaches a new set pressure value). It is not necessary to perform the pressure adjustment work to output at.

When this pressure reducing valve is used in a system as shown in FIG. 3, for example, one pressure reducing valve also functions as a pressure switch, so that the pressure switch (107) can be omitted and the cost of parts can be reduced. Also, as described above, since the setting for generating the confirmation signal at the desired timing by the pressure adjustment for setting the secondary side pressure is also performed at the same time, not only the pressure adjustment work is halved, but also the latter (confirmation signal (The occurrence timing of) occurs completely, and the system reliability can be improved.

Further, the pressure reducing valve of this embodiment can be manufactured at a low cost by modifying the existing direct acting type pressure reducing valve. In this case, since the lower end of the valve stem of the existing direct acting pressure reducing valve is short, it may be replaced with a longer one or the extension may be joined to the lower end.

When the secondary pressure reaches the set pressure value and then becomes low for some reason, the diaphragm 18 loses balance and the valve body 36 is pushed down to separate from the valve seat 40. Then, the compressed air from the primary side is sent to the secondary side, and the secondary side pressure reaches the set pressure value again. At this time as well, the position sensor 52 operates to generate the confirmation signal. If such a signal causes a malfunction in the system, a latch circuit such as a flip-flop may be provided so that only the first confirmation signal is valid.

Embodiment 2 FIG. 2 shows the construction of a direct acting type pressure reducing valve according to the second embodiment. In the figure, conventionally known parts having the same functions as those of the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted.

The characteristic part of this embodiment will be described. First, the piston 60 is arranged between the shorter pressure adjusting spring 12 and the diaphragm 18. The upper end of the piston 60 receives the lower end of the pressure adjusting spring 12, and the lower end of the piston 60 is the diaphragm.
It is stuck to 18. As a result, the piston 60 moves up and down integrally with the diaphragm 18 according to the balance between the pressure set by the pressure adjusting spring 12 and the secondary pressure.

A chamber 62 is provided inside the piston 60, and one end of each of the movable terminal 64 and the conductor plate 66 is provided with a screw 68 at the bottom of the chamber 62.
It is fixed by. The other end of each of the movable terminal 64 and the conductor plate 66 extends into the sensor box 70 attached to the side surface of the bonnet 10, and the other end of the movable terminal 64 is a negative terminal of the power supply section 74 via the lead wire 72. The movable contact 76 is coupled to the other end of the conductor plate 68. A fixed contact 78 is provided directly above the movable contact 76 so as to face the movable contact 76,
The fixed contact 78 is connected to the + terminal of the power supply unit 74 via the fixed terminal 80 and the conductor wire 82.

Thus, the movable contact 76 is configured to move up and down integrally with the diaphragm 18 or the piston 60 in accordance with the balance between the pressure set by the pressure adjusting spring 12 and the secondary pressure.
Moreover, when the secondary side pressure reaches the set pressure value and the valve body 36 comes into contact with the valve seat 40, the movable contact 76 comes into contact with the fixed contact 80, thereby closing the circuit of the power supply unit 74 and outputting an electric signal. Is set. This electric signal is sent as a set pressure confirmation signal via a cable 84 to an external device, for example, a resistance welding machine as shown in FIG.

Also in the second embodiment, the same advantages as those of the first embodiment can be obtained with respect to the adjustment of the set pressurization value. Also, regarding the manufacturing, although the mounting structure of the movable terminal 64 and the movable contact 76 is a little complicated, it is not necessary to use a proximity switch or a photoelectric switch, and if necessary, the sensor box can be installed on the bonnet rather than the bottom of the valve body. It may be better to attach it to the side. However, it is also possible to provide a proximity switch or a photoelectric switch in the sensor box 70.

When the secondary pressure becomes higher than the set pressure value,
When the piston 60 rises while the movable contact 76 and the fixed contact 78 are in contact with each other, a strong strain force is applied to the conductor plate 66 and the movable terminal 64. In this regard, there is no problem if the conductor plate 66 and the movable terminal 64 have elasticity.

Although two preferred embodiments have been described above, various modifications and changes can be made within the scope of the technical idea of the present invention. For example, the lower end portion of the valve stem 34 in the first embodiment and the piston 60 in the second embodiment each function as a movable body integral with the diaphragm, but various other movable bodies are possible. Also, various types of position sensor means can be used. It is also possible to provide a position sensor that directly detects the position (displacement) of the diaphragm. Further, although any of the above-described embodiments is a direct acting type pneumatic pressure reducing valve, the present invention is also applicable to other types of pneumatic pressure reducing valve such as pilot type and various pressure reducing valves for hydraulic pressure.

(Effects of the Invention) As described above, according to the present invention, the pressure reducing valve itself outputs the confirmation signal when the secondary side pressure reaches an arbitrary set pressure value, so that the pressure adjustment work is troublesome. While being halved, the problem of forgetting to adjust the confirmation signal can be completely eliminated.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a direct acting pressure reducing valve according to the first embodiment of the present invention, and FIG. 2 is a sectional view showing the structure of a direct acting pressure reducing valve according to the second embodiment of the present invention. FIG. 3 and FIG. 3 are block diagrams showing a configuration of a conventional typical pneumatic system and a resistance welding machine using the same as a pressurizing means. 12 …… Pressure adjusting spring, 16 …… Pressure adjusting screw, 18 ……
Diaphragm, 26 …… IN port, 28 …… OUT port, 34 …… Valve stem, 36 …… Valve element, 40 …… Valve seat, 50,70 …… Sensor box, 52 …… Position sensor, 60 …… Piston , 76 ……
Moving contact, 78 ... Fixed contact, 74 ... Power supply section.

Claims (3)

[Claims] 1. A pressure adjusting spring for setting a secondary side pressure, a first surface for receiving pressure from the spring, and a second surface for receiving the secondary side pressure. And a pressure balance means that is displaced according to the pressure respectively received on the second surface, a valve body that is interlocked with the pressure balance means, and contacts the valve body when the secondary-side pressure becomes equal to or higher than a set pressure value. And a position sensor means for detecting the position of the pressure balance means when the valve body and the valve seat are in contact with each other and outputting an electrically set pressure confirmation signal. A pressure reducing valve comprising: 2. The position sensor means detects the position of the pressure balance means by detecting the position of the valve body when the valve body and the valve seat contact each other, and outputs the set pressure confirmation signal. The pressure reducing valve according to claim 1, wherein the pressure reducing valve outputs the pressure. 3. The pressure balance means is provided with a contact, and when the valve body and the valve seat come into contact with each other, the contact comes into contact with the set pressure confirmation signal to be output. The pressure reducing valve according to claim 1.