JPH01309105A - Pneumatic pressure reducing valve with relief - Google Patents

Abstract

PURPOSE:To control the secondary pressure at a desired level despite the change of the flow rate due to the flow, the cut-off, etc., of the air by shifting a piston in accordance with the operation of an pneumatic circuit to change the energizing force of a control spring and performing the switch between the flow rate and the secondary pressure characteristics. CONSTITUTION:A piston 24 set in a back pressure room 22 of a diaphragm 3 is slided by a switch mechanism 7 as soon as the shift of a cylinder is started. Thus the energizing force of a control spring 28 is changed and the flow rate and the secondary pressure characteristics of a pressure reducing valve 1 with relief are changed. Under such conditions, the flow rate of the valve 1 is changed to a prescribed level and the switch is performed between the flow rate and the secondary pressure characteristics so that the secondary pressure value is equal to said flow rate when the operation of the cylinder is stopped, i.e., when the flow rate is equal to zero. In addition, the flow rate and the secondary pressure characteristics are switched to their original states again via the mechanism 7 when the operation of the cylinder is stopped. Thus the change of the secondary voltage is suppressed for the 1st and 2nd pressure reducing valves in both the flow and cut-off states of the air. In such a constitution, an air pressure cylinder is satisfactorily operated.

Description

Detailed Description of the Invention Purpose of the Invention [Industrial Application Field] The present invention is used in a pneumatic circuit for operating a pneumatic cylinder, and reduces the pressure to a constant pressure lower than the next pressure to lower the pneumatic pressure in the downstream circuit. This article relates to a pressure reducing valve with relief for setting.

[Prior Art] Conventionally, a pressure reducing valve with a relief has been used in a pneumatic circuit for vertically moving, stopping, etc. a heavy object by the operation of a pneumatic cylinder having an intermediate stop mechanism. The first example is
As shown in Figure 0, this pneumatic circuit reduces the pressure supplied from a pressure source A1 to a constant pressure by an intimidation valve B1 (equipped with a releaser), and then connects a closed center type 5-bottom 3
A cylinder operating circuit is configured to supply air pressure to the pneumatic cylinder D1 with a stop mechanism via the position changeover valve C1, and by switching the changeover valve C1, the pressure in the head chamber E1 and rod chamber F1 of the pneumatic cylinder D1 with a stop mechanism is controlled. The pneumatic cylinder D1 is operated by supplying or exhausting air. In addition, a pressure reducing valve with relief G1, a check valve H1, and an exhaust throttle valve J1. f(1) is used to control the pressure of the heavy load L1, such as adjusting the speed and adjusting the pressure during intermediate stops.

In such a configuration, when the pneumatic cylinder D1 is stopped,
The head chamber E1 and the rod chamber F1 are separated from the pressure source A1, but as shown in FIG.
It is also conceivable to use an oven center type valve as the position switching valve C2 and apply pressure even when the valve is stopped. In this case, at the time of intermediate stop, pressure is supplied to the head chamber E2 and the rod chamber F2, and the pressure is further applied by the pressure reducing valve B2°G2 with relief to the downward thrust due to the pressure of the heavy load L2 and the head chamber E2, and the rod chamber F2. The pressure is regulated so that the upward thrust due to the pressure of

[Problems to be Solved by the Invention] However, in the pneumatic cylinder operation circuit using such a pressure reducing valve with relief, when moving a heavy object up and down,
In the case where the piston rod is mechanically gripped and stopped by the stop mechanism part midway through the movement and then moved up and down again, the following problems occur.

In the pneumatic circuit shown in Fig. 10, if the pressure in both the head chamber E1 and the rod chamber F1 is maintained at an intermediate stop state, air leakage may occur at the gasket in the cylinder Dl or at each valve. As a result, the pressure in both chambers E1 and Fl becomes unbalanced, and the moment the grip on the stop mechanism M1 is released, the piston suddenly moves to the side with lower pressure, causing problems such as the so-called pop-out phenomenon. There was a problem.

In order to reduce this protrusion phenomenon, a pneumatic circuit as shown in Fig. 11 is used, but generally,
The flow rate/secondary pressure characteristics of the pressure reducing valve are as shown in FIG. 12, and as the flow rate changes, the secondary pressure also changes. Therefore, while the cylinder D2 is moving, the secondary pressure decreases as air flows, but the exhaust throttle valve J2. When the piston N2 is set to the desired moving speed by adjusting step 2, the flow rate becomes F B as shown in FIG.
(Q /m1n), the secondary pressure at that time will be P B (kg f /cm2G).

Next, when the switching valve C2 is operated to stop the cylinder D2 midway, the flow rate becomes OCQ1m group).

Therefore, as shown in Figure 12, the secondary pressure at this time is PA
(kg f /cm2G) and is supplied to both chambers in cylinder D2.

Again, when moving the cylinder D2 again, the exhaust throttle valve J2. The adjustment amount of 2 corresponds to the aforementioned secondary pressure P B (kg f / 0 m2G) during movement of the cylinder D2. Therefore, immediately after the re-movement of cylinder D2 starts, in both chambers E2°F2 in cylinder D2, the pressure in the chamber on the side where air is supplied becomes higher than necessary compared to the side on which air is exhausted. Put it away. For this reason, the pressure balance for maintaining a predetermined speed suddenly collapses immediately after the cylinder D2 starts moving again, and the exhaust throttle valve J2 for speed control. Despite the two adjustments, cylinder D2 begins to move abruptly in its direction of movement. As a result, a so-called protrusion phenomenon occurs.

Due to this protrusion phenomenon, both chambers P in the cylinder D2:
2. The pressure inside F2 constantly fluctuates, and the speed of cylinder D2 during movement becomes unstable, and in some cases, the cylinder D2 moves as if it were moving while taking pictures. Therefore, there was a problem in that the control unit for the stop position of the cylinder D2 and furthermore the stability was insufficient.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a pressure reducing valve with a pneumatic relief that can suitably operate a pneumatic cylinder by controlling the secondary pressure in a pneumatic cylinder operating circuit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the pressure reducing valve with relief for pneumatic pressure according to the present invention, which has been made to achieve the above object, will be described.

[Means for Solving the Problems] The first pressure reducing valve with relief for pneumatic pressure of the present invention is used in a pneumatic circuit for operating a pneumatic cylinder, and a pneumatic pressure reducing valve for reducing the secondary pressure to a constant pressure lower than the primary pressure. In the pressure reducing valve with a relief, a piston equipped with an adjustment spring that biases the diaphragm that receives the secondary pressure toward the pressure receiving chamber is slidably provided in the back pressure chamber of the diaphragm, and the piston is slidably provided in the back pressure chamber of the diaphragm. The present invention further includes a switching mechanism that moves the piston to change the biasing force of the adjustment spring in response to the operation of the pneumatic circuit that switches between flow through and cutoff of the pressure reducing valve. Features.

The second pressure reducing valve with relief for pneumatic pressure is used in a pneumatic circuit for operating a pneumatic cylinder, and in the pressure reducing valve with relief for pneumatic pressure that reduces the secondary pressure to a constant pressure lower than the primary pressure, the second pressure reducing valve with relief A piston equipped with an adjustment spring that biases a diaphragm that receives pressure toward a pressure receiving chamber is slidably provided in a back pressure chamber of the diaphragm, and operation of the pneumatic circuit that switches between passing through and blocking air in the pressure reducing valve. A switching mechanism is provided that moves the piston to change the biasing force of the adjustment spring to switch the flow rate/secondary positive characteristic of the pressure reducing valve, and when the secondary pressure is lower than the set pressure, the switching mechanism changes the biasing force of the adjustment spring. A mechanism that increases the flow rate from the secondary pressure side to the secondary pressure to raise the secondary pressure, and a mechanism that increases the flow rate from the secondary pressure side to the atmosphere side to reduce the secondary pressure when the secondary pressure is higher than the set pressure. The feature is that the mechanism is provided separately.

Here, the switching mechanism refers to a mechanism having various configurations for moving a piston, such as by using fluid pressure such as air pressure or oil pressure, an actuator such as a motor or solenoid, or manually. Various mechanisms can be considered. Such a mechanism may be provided inside the pressure reducing valve or may be provided outside.

[Operation] The first aspect of the present invention having the above configuration. The second pneumatic pressure reducing valve with relief supplies a constant pressure to the head chamber or rod chamber of the cylinder when the cylinder is operated, ie, moved, stopped, etc., in the pneumatic circuit that operates the pneumatic cylinder.

When the cylinder starts moving, at the same time, the switching mechanism slides the piston provided in the back pressure chamber of the diaphragm to change the biasing force of the adjustment spring, thereby adjusting the flow rate and secondary positive characteristics of the pressure reducing valve with relief of the present invention. change. At this time, the flow rate changes to a predetermined value, but the flow rate/secondary positive characteristic is switched so that the value of the secondary pressure for that flow rate becomes approximately the same value as when the cylinder is stopped, that is, when the flow rate is 0. Furthermore,
When the cylinder is stopped, if the switching mechanism is used again to switch the flow rate/quadratic positive characteristic to the initial characteristic, as a result, the first characteristic of the present invention. In the second pressure reducing valve, changes in the secondary pressure are suppressed both when air flows through and when air is blocked. Therefore, even when the cylinder is moved again from an intermediate stop state, the secondary pressure maintains a nearly constant pressure and supplies air to the cylinder, so the cylinder starts moving smoothly and the phenomenon of popping out is reduced. be done.・Furthermore, the second pressure reducing valve with pneumatic relief uses a separate mechanism to quickly reduce the secondary pressure whether the secondary pressure becomes higher or lower than the set pressure. control.

[Example] Hereinafter, a pressure reducing valve with pneumatic relief as a preferred example of the present invention will be described. FIG. 1 is a sectional view showing a first embodiment of the first pneumatic pressure reducing valve with relief of the present invention. As shown in the figure, the pressure reducing valve 1 with a pneumatic relief according to the first embodiment has an adjustment main body part 2. The pressure reducing valve body 5 includes a diaphragm 3 and a valve body portion 4, and a three-bottom, two-position switching valve 7 used as a switching mechanism.

The adjustment main body 2 includes a bonnet 21 having one end screwed onto a hollow adjustment screw 20 having a wide portion 20a, and a back pressure chamber 22 is provided at the other end of the bonnet I 21 on the diaphragm 3 side. It is being A hollow piston 23 is slidably fitted into the back pressure chamber 22, and a hollow piston rod through which the adjusting screw 20 is inserted has a contact portion 24a at its end. 24 is formed. A bleed hole 22a is provided at the end of the piston rod 24 on the contact portion 24a side to release the pressure in the back pressure chamber 22 to the atmosphere.
A spring adjusting screw 26 with a handle 25 is screwed therein. The spring adjustment screw 26 is brought into contact with an adjustment spring 28 provided in the hollow portions of the piston 23 and the piston rod 24 via a spring presser 27 . As a result, the urging force applied to the diaphragm side on the second adjustment scale can be adjusted.

An adjustment chamber 29 and an adjustment chamber boat 30 communicating from the adjustment chamber 29 to the outside of the pressure reducing valve main body 5 are provided on the piston rod 24 side of the piston 23, and are connected to the three-bottom, two-position switching valve 7. This three-bottom, two-position switching valve 7 will be described later.

The diaphragm 3 provided between the adjustment main body 2 and the valve main body 4 has a relief hole 31 in its center.
A relief valve 32 having a pressure relief valve 32 is provided, and is biased in the valve body 4 direction by an adjustment spring 2.

The valve body portion 4 is provided with a secondary pressure chamber 41, a secondary pressure chamber 42, and a pressure receiving chamber 43 located on the diaphragm 3 side and communicating with the secondary pressure chamber 42 via an orifice 42a.

- A valve body 45 is provided between the secondary pressure chamber 41 and the secondary pressure chamber 42 so as to be slidable in the valve body chamber 46, and the valve body 45 is connected to the diaphragm by a valve spring 47 on the side of the valve body chamber 46. While being biased in three directions, the valve head 45a is in contact with the valve seat 48.

Further, the valve head 45a is in contact with a stem 49, and the other end of this stem 49 is connected to the relief valve 32 of the diaphragm 3.
is in contact with. Therefore, the stem 49 transmits the downward movement of the relief valve 32 to the valve body 45 to cause the valve body 45 to slide downward, and the relief hole 31 of the relief valve 32
doubles as opening and closing. On the other hand, the secondary pressure chamber 41 is provided with a primary pressure port 41a, which is connected to the 3-point/2-position switching valve 7.

Adjustment chamber port 3 communicating with adjustment chamber 29 in adjustment main body 2
0 and a primary pressure valve (41a) communicating with the primary pressure valve (41) in the valve body 4.
is the normal state where solenoid 7a is not energized,
The air in the adjustment chamber 29 is released to the atmosphere through the adjustment chamber port 30, and the -subpressure chamber boat 41 is closed. On the other hand, by energizing the solenoid 7a, the 3-bot 2-position switching valve 7
When you operate the adjustment chamber port 30 and the primary pressure boat 41a
The pressure in the secondary pressure chamber 41 is supplied to the adjustment chamber 29.

The pressure reducing valve 1 with a pneumatic relief according to the present embodiment having the above-mentioned configuration is used in a pneumatic circuit for operating a pneumatic cylinder, etc., and reduces the secondary pressure to a constant pressure lower than the negative secondary pressure. With the air in the adjustment chamber 29 exhausted to the atmosphere by the 3-point 2-position switching valve 7 in the normal state, when the handle 25 is turned to increase the biasing force on the adjustment valve 2, the relief valve 32
The valve body 45 slides in the direction of the valve body chamber 46 via the stem 49 and the air from the secondary pressure chamber 41 passes through the valve and enters the secondary pressure chamber 42.
flows into. At this time, part of the air at the secondary pressure M42 flows into the pressure receiving chamber 43 through the orifice 42a, moves the relief valve 32 of the diaphragm 3, and pushes up the adjustment spring 28. In response, the stem 49 moves upward, and the valve begins to close due to the valve element 45 being urged upward by the valve spring 47 until the valve element 45 reaches a position where the urging forces of the secondary pressure and the adjustment spring 28 are balanced. moves, and the secondary pressure is set to a constant pressure. Further, when the secondary pressure exceeds the set pressure, the pressure inside the pressure receiving chamber 43 increases, and the diaphragm 3 and the relief valve 32 are pushed up above the stem 49, the relief hole 31 opens, and the air in the pressure receiving chamber 43 is released. Bleed hole 2
2a to the atmosphere. As a result, the secondary pressure is always maintained within a certain range regardless of the air flow.

The valve body 45 is provided with a valve body hole 45b that communicates the secondary pressure chamber 42 and the valve body chamber 46, thereby transferring the influence of pressure fluctuations on the secondary pressure chamber 41 side to the secondary pressure chamber 42 side. They are trying not to tell you.

Next, by energizing the solenoid 7a, the 3-point/2-position switching valve 7 is operated to divert the air from the negative pressure chamber 41 side to the adjustment chamber 2.
9, the air pressure in the adjustment chamber 29 causes the piston 23 and the piston rod 24 to move toward the diaphragm 3, only by the distance until the contact part 24a of the piston rod 24 contacts the wide part 20a of the adjustment screw 20. Sliding. This increases the biasing force of the adjustment spring 28, and as a result,
The secondary pressure changes from the pressure set by the handle 25, and the flow rate and
The secondary positive characteristic will be switched.

As shown in the flow rate/secondary positive characteristic graph in FIG. 2, when the flow rate/secondary positive characteristic when the air in the adjustment chamber 29 is exhausted to the atmosphere is represented by the characteristic line (A), ? M firefly 0 (Q/m
in), the secondary pressure is PO (kgf/ctn”C;
) However, when the flow rate is Fl (G!/min), the secondary pressure drops to P 1 (kg f /cn+2G). At this time, when the adjusting screw 20 is moved to adjust the sliding distance of the piston 23 and the 3-bot 2-position switching valve 7 is used to flow air into the adjustment chamber 29,
By sliding the piston 23, adjustment is made so that the flow rate/secondary positive characteristic as a pressure reducing valve is switched to the characteristic line (B). Therefore, according to the characteristic line (A), when the flow rate changes from O (Q/m1n) to Fl ((2/+++in), 3
By operating the button 2-position switching valve 7 and switching to the characteristic line (B), the flow rate and secondary positive characteristics of the pressure reducing valve with pneumatic relief of this embodiment are the same as the characteristic line (C). Therefore, the secondary pressure is almost constant pressure P O (kg f /am
” G) will be maintained.

Next, a pneumatic circuit using the pressure reducing valve with pneumatic relief of the first embodiment will be further explained based on FIGS. 2 and 3. FIG. 3 is a pneumatic-pressure circuit diagram showing the pneumatic cylinder operating circuit in this embodiment. As shown in the figure, this pneumatic cylinder operation circuit includes a pressure source 50, the aforementioned pressure reducing valves 1a and 1b with pneumatic relief (hereinafter referred to as pressure reducing valves), and 3-point and 2-position switching valves 51 and 52 (hereinafter referred to as pressure reducing valves). (referred to as a switching valve), a pneumatic cylinder 60 having a piston rod grip mechanism 60a, and the like. Further, as shown in FIG. 2, a pressure reducing valve 1a.

1b, each flow rate/secondary positive characteristic is, for example, the characteristic Lm
Handle 2 to switch between (A) and characteristic line (B).
5 and adjustment screw 20. To be exact,
Although the characteristic lines of the flow rate and quadratic positive characteristics of the pressure reducing valve 1a and the pressure reducing valve 1b in this pneumatic circuit are not the same, the principle of switching the characteristics is the same, so no special distinction will be made hereafter. , the characteristic line (A) of the graph in Figure 2,
This will be explained using (B) and (C).

The piston rod 61 is attached to the piston rod grip mechanism 60
When the pneumatic cylinder 60 is brought into a stopped state by gripping the air pressure cylinder 60, the air in the adjustment chambers 29 of the pressure reducing valves 1a and 1b is exhausted by the switching valves 7a and 7b which are in the normal state.

In this state, the secondary pressure of the pressure reducing valves 1a and 1b is due to the downward thrust caused by the heavy object 65 and the pressure in the head chamber 62, and the pressure in the rod chamber 6.
The pressure is regulated so that the upward thrust generated by the pressure chamber No. 3 is equal to the upward thrust. Also, what about the pressure reducing valves 1a and lb at this time? M, quantity/quadratic positive characteristics are on the low pressure side, that is, as shown in the characteristic line (A) of the graph shown in FIG.

From this state, for example, when operating the cylinder 60 to move the heavy object 65 downward, the piston rod is released by the piston rod grip mechanism 60a, and the switching valve 52 connected to the rod chamber 63 side is released.
is operated to exhaust the air in the rod chamber 63 via the exhaust throttle valve 52a for adjusting the descending speed. At this time, the switching valve 7a is switched at the same time. As a result, the flow rate/secondary positive characteristic of the pressure reducing valve 1a simultaneously switches to the characteristic line (B) in FIG. 2, and a constant secondary pressure is maintained even if the flow rate changes. Incidentally, when stopping the pneumatic cylinder 6.0, the switching valve 7a is switched at the same time. As a result, the flow rate/quadratic positive characteristic of the pressure reducing valve 1a switches again to the characteristic line (A) in FIG.

By repeating the above-mentioned operations, even if the flow rate changes due to the stoppage or movement of the pneumatic cylinder 60, the pressure supplied from the pressure reducing valve with pneumatic relief will be reduced to
), the pressure remains constant, and the pressure in the head chamber 62 or rod chamber 63 does not fluctuate.

As explained above, the pressure reducing valve 1 with pneumatic relief of this embodiment is capable of keeping the secondary pressure constant even if the flow rate changes due to stopping or moving the cylinder 60, so that the pneumatic cylinder can be operated There is no sudden movement during operation of the cylinder 60 in the circuit, that is, no protrusion phenomenon occurs, and the moving speed of the cylinder 60 can be stabilized, and the stop position of the cylinder 60 can be suitably controlled. It becomes self-intent.

Furthermore, in this embodiment, as a switching function, the supply and exhaust of air to and from the adjustment chamber 29 for sliding the piston 23 in the adjustment main body 2 are controlled by a general-purpose 3-bot 2-position switching valve 7 and a 2-position switching valve 7. Since the air pressure within the pressure chamber 41 is utilized, a configuration based on these can be easily realized. Further, the flow rate/secondary positive characteristics can be adjusted by changing the characteristics by operating the handle 25 and changing the characteristics by operating the adjusting screw 20.
It is extremely easy to do.

The pressure reducing valve with relief for pneumatic pressure 1 of this embodiment can of course be used as a pressure control valve not only in a pneumatic cylinder operation circuit but also in various pneumatic circuits.

Next, an embodiment of the second pressure reducing valve with pneumatic relief of the present invention will be described. FIG. 4 is a sectional view showing the configuration of an embodiment of the second pressure reducing valve. As shown in the figure, the pressure reducing valve 100 with pneumatic relief of the present embodiment has a pressure reducing valve main body 105 consisting of an adjustment main body part 102, a diaphragm 103, and a valve main body part 104, and a switching mechanism, similar to the first embodiment. However, compared to the first embodiment, the configuration is different in the following points.

(1) A recess 123a is formed in the lower end surface of the hollow piston 123 of the adjustment body 102, and the spring i of the end of the bonnet 121 facing the recess 123a
A return spring 133 is disposed between the spring 121a and the spring 121a. The return spring 13:3 has a low set pressure of the secondary pressure set by the adjustment spring 128 (in some cases Okg f
/am2G) is also provided to maintain good responsiveness when the piston 123 returns.

(2) The relief valve 132 attached to the diaphragm 103 is formed with a sliding shaft portion 134 extending toward the valve body 104 side, and a second valve body 136 is formed on this sliding shaft portion 134. is slidably fitted on the outside. This second valve body 1
36 is an exhaust boat 13 provided in the pressure reducing valve main body 105
8 and the secondary pressure chamber 142, and is urged toward the valve seat 144 by a spring 143.

In addition, the second valve body 136 is provided with:
A valve hole 136b is provided.

(3) A threaded portion is formed at the tip of the sliding shaft portion 134 of the relief valve 132, and a stem 149 is fixed thereto. The stem 149 is in contact with the valve head 145a at the upper end of the first valve body 145, and the stem 149 is in contact with the valve head 145a at the upper end of the first valve body 145. Second valve body 1
Drive 45.136.

In the pressure reducing valve 100 with pneumatic relief of the second embodiment configured as described above, the flow rate and quadratic positive characteristics are switched by the operation of the switching valve 107, similar to the pressure reducing valve 1 of the first embodiment. Furthermore, when the secondary pressure fluctuates, the operation is as follows.

When the secondary pressure becomes lower than the set pressure, the force received by the diaphragm 103 and the spring 147 of the first valve body 145
Since the balance between the sum of the urging forces of the spring 128 and the urging force of the spring 128 is lost, the relief valve 132 is pushed down. As a result, the first valve body 145 is pushed down, high-pressure air flows from the secondary pressure chamber 141 to the secondary pressure chamber 142, and the secondary pressure immediately rises and is regulated to the set pressure.

On the other hand, when the secondary pressure becomes higher than the set pressure, the balance of forces acting on the relief valve 132 is adversely disrupted, and the relief valve 132 moves upward. As a result, the second valve body 13
6 is pushed up, a large amount of the high pressure air in the secondary pressure chamber is exhausted to the exhaust boat 138 side, and the pressure in the secondary pressure chamber 142 is immediately reduced and regulated to the set pressure. In the first embodiment, when the secondary pressure becomes higher than the set pressure, the pressure is adjusted by allowing the air that has passed through the relief valve 32 from the orifice 42a to further escape to the atmosphere through the bleed hole 22a. , compared to this, the pressure regulation in the pressure reducing valve 100 of this embodiment is extremely quick.

Next, a pneumatic circuit using the pressure reducing valve 100 with pneumatic relief of the second embodiment will be further explained based on FIG. 5. FIG. 5 shows the pressure reducing valve 1 with pneumatic relief of this embodiment.
It is a pneumatic circuit diagram showing a pneumatic cylinder operation circuit using 00a and 100b.

As shown, this pneumatic cylinder operation circuit includes a third
Similar to the first embodiment shown in the figure, a pressure source 150, the aforementioned pressure reducing valves 100a and 100b with pneumatic relief,
3-point/2-position switching valve 107a.

107b, a pneumatic cylinder 160 having a piston rod grip mechanism 160a, and the like.

Figure 6 (A) shows the flow rate and secondary positive characteristics when air flows through the pressure reducing valves 100a and 100b from the primary pressure side to the secondary pressure side.
In addition, the characteristics when air flows from the secondary pressure side to the exhaust side are shown in FIG. 6(B). As shown in the figure, the handle 125 and the adjustment screw 120 are adjusted so that when the 3-point/2-position switching valves 107a and 107b are switched, the characteristic line is changed to PA or PB, and characteristic line QA or QB. do. In addition, the pressure reducing valve 100a and the pressure reducing valve 100b are configured to have a secondary Pressure is regulated.

In the pneumatic circuit configured as described above, the switching valve 1
Switch both 07a and 107b to the normal position Dυ,
The flow rate/quadratic positive characteristics are shown on the low pressure side (Fig. 6 (A), (B)).
characteristics of the pneumatic cylinder 16 when closed (PA, QA side)
It is assumed that the forces acting on the piston port 161 are balanced, and the piston rod 161 is held stationary by the piston rod grip mechanism 160a. From this state, the grip mechanism 160 is released, and the switching valve 107a is
When is switched to the position UP side, the first pressure forming valve 100a becomes the pressure side, the pressure reducing valve 100b becomes the back pressure side, and the flow rate/secondary positive characteristic of the pressure reducing valve 100a is switched to the characteristic PB side in FIG. 6. As a result, the piston rod 161 begins to descend. As the piston rod 161 descends, air begins to flow into the upper chamber of the piston port 161 via the pressure reducing valve 100a, so the pressure changes from point PAO to point PBt in FIG. 6(A).

On the other hand, the air in the lower chamber of the piston rod 161 is transferred to the pressure reducing valve 10.
The pressure that flows through 0b and becomes the back pressure side is shown in Fig. 6 (
B) Changes from point QAO to point QAt. As a result, the piston rod 161 of the pneumatic cylinder 160 is lowered at a speed corresponding to the difference between the two pressures PBt and QAt (more precisely, the thrust force and load W, which are the products of each pressure and its pressure receiving area). become.

On the other hand, when the switching valve 107b is switched to the position tJP while the switching valve 107a is held at the position DW, the pressure reducing valve 10
The 0b side is the pressure side, and the flow rate and secondary positive characteristics are shown in Figure 6 (A
) Switches to characteristic PB. In addition, the pressure reducing valve 100a is on the back pressure side, and its flow rate/secondary positive characteristic is shown in FIG.
Switch to A. As a result, the piston rod 161 is raised.

As explained above, the pneumatic circuit using the pneumatic relief pressure reducing valves 100a and 100b of this embodiment allows the cylinder rod 161 of the pneumatic cylinder 160 to be smoothly moved, stopped, and restarted. This means that whether the air flow rate is large or small, the pressure reducing valves 100a and 100b with pneumatic relief adjust the secondary pressure extremely sensitively, and the secondary pressure is adjusted to the pressure (
By adjusting the setting pressure) and switching the switching valve 107, the flow rate/secondary positive characteristic can be changed, and the secondary characteristic when the pressure reducing valve IQOft is changed from a state where no air is flowing to a state where a predetermined flow rate is flowing. This is because the pressure can be adjusted to a predetermined pressure.

Furthermore, since pressure control is adopted in this embodiment, the pressure of the piston rod 161 is lower than that of the pneumatic circuit of the first embodiment (Fig. 3), which uses a back pressure control method using an exhaust throttle valve for speed adjustment. It has the advantage of being able to move smoothly.

In other words, in a system using an exhaust throttle valve, if you want to descend at a slow speed, you have to reduce the throttle of the speed control valve.
For this reason, the start of the downward movement tends to be relatively slow, but in this embodiment, since pressure control is adopted, such a problem does not occur. Further, the speed of descent can be adjusted separately depending on the flow rate and secondary positive characteristics on the high pressure side of the pressure reducing valve 100a, and the speed of rising can be adjusted separately depending on the flow rate and secondary positive characteristics on the high pressure side of the pressure reducing valve 100b. Furthermore, in the case of a midway stop, the pressure in both chambers of the piston rod is maintained, whereas in the case of a back pressure control method, the pressure in both chambers of the piston rod is maintained, so there is an advantage that control is simplified.

In addition, in the pneumatic circuit using the pressure reducing valve of this embodiment, the air balance of the cylinder 160 is maintained when both pressure reducing valves have a flow rate/quadratic positive characteristic on the low pressure side.

However, it may be configured to maintain air balance when both valves select the high pressure side. In this case, since it is necessary to adjust the biasing force of the spring 133 to a desired value when changing to the characteristics on the low pressure side, an adjusting screw 220 is provided as shown in FIG. This can be realized by adjusting the retreat distance LB. When balancing at high pressure, one switching valve 107a (
Alternatively, switch b) to position DW and open the pressure reducing valve 100.
The flow rate/quadratic positive characteristic of a (or b) in FIG. 6(B) is switched from characteristic QB to QA. Since air begins to flow through the pressure reducing valves 100a and 100b, the pressure on the back pressure side changes from point QBO to point QAt, and the pressure on the pressurizing side changes from point PBO to point P.
Changes to Bt. As a result, due to the pressure relationship (PBt>QAt) on both sides of the piston rod 161, the cylinder 1
The piston rod 161 of 60 will be moved to the low pressure side.

Next, other embodiments of the present invention will be described. 8th
9 are sectional views showing other configuration examples of the second pressure reducing valve with pneumatic relief of the present invention. This pressure reducing valve 300
is the relief valve 3 attached to the diaphragm 303
32, and a valve body 330 that abuts a downward tip of the relief valve 332. As can be seen from the figure, when the secondary pressure falls below the set pressure, the valve body 330 is pushed down from the relief valve 332, and the secondary pressure rapidly rises. - direction,
When the secondary pressure exceeds the set pressure, the relief valve 332 moves upward and away from the valve body 330, and the secondary pressure rapidly decreases. Further, as in the other embodiments described above, the piston 323 is moved by a certain distance by switching the 3-port 2-way switching valve 307, and the flow rate/secondary positive characteristic is switched.

As shown in FIG. 9, the valve main body of the pressure reducing valve with pneumatic relief 400 includes two valves IEIM422. 424 may be movably attached to the tip of the relief valve 432. This pressure reducing valve 400 also operates in the same manner as in the previously described embodiments.

Several embodiments of the present invention have been described above, but
The first aspect of the present invention. The pressure valve (with second pneumatic relief) is not limited to these embodiments; for example, it may have a configuration that uses hydraulic pressure as a switching mechanism, or a configuration in which the piston is directly slid by an actuator such as a motor or solenoid. , within the scope of the invention,
Of course, it can be implemented in various ways.

Effects of the invention 1. Effects of the invention. The second pneumatic pressure reducing valve with relief can switch the flow rate and secondary positive characteristics using the switching mechanism, so even if the flow rate changes due to air leakage, blockage, etc., the secondary pressure This has the excellent effect of being able to suitably control the pressure to a desired level. Therefore, for example, when used in a pneumatic cylinder operation circuit, the speed of the pneumatic cylinder during movement can be stabilized without causing sudden movement of the pneumatic cylinder, the so-called protrusion phenomenon. It becomes possible to suitably control the stop position.

In addition to this, the second pneumatic pressure reducing valve with relief of the present invention rapidly reduces the secondary pressure not only when the secondary pressure falls below the set pressure but also when it exceeds the set pressure.・
can be controlled. Therefore, for example, when used in a pneumatic cylinder operating circuit, pressure control becomes possible, and the number of component parts can be reduced and control simplified.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing an embodiment of the first pressure reducing valve with pneumatic relief of the present invention, Fig. 2 is a graph showing flow rate and secondary pressure characteristics in the embodiment, and Fig. 3 is a pressure reducing valve of this embodiment. Pneumatic circuit diagram showing a pneumatic cylinder operating circuit using a valve, No. 4
The figure is a sectional view showing an embodiment of the second pressure reducing valve with relief for pneumatic pressure of the present invention, FIG. 5 is a pneumatic circuit diagram showing a pneumatic cylinder operation circuit using the pressure reducing valve of this embodiment, and FIG. 6 (A
). (B) is a graph showing the characteristics of the pressure reducing valves 100a and b, respectively;
FIGS. 7, 8, and 9 are sectional views showing other configuration examples, and FIGS. 10 and 11 are pneumatic circuit diagrams showing pneumatic cylinder operation circuits using conventional pressure reducing valves with relief, respectively, FIG. 12 is a graph showing an example of flow rate/secondary pressure characteristics of a conventional pressure reducing valve with relief. L 100,300,400...Pneumatic pressure reducing valve with relief 2.102...Adjustment body part 3.103,303...Diaphragm, 4.104.
... Valve body part 5.105... Pressure reducing valve main body 7.107, 307... 3-point and 2-position switching valve 20.
120...Adjustment screw 21.121...Bonnet, 22...Back pressure chamber 23.123...Piston 24
... Piston rod 25.125 ... Handle 2G ... Spring adjustment screw 28.128 ... Adjustment spring 29 - ... Adjustment chamber 30 ... Adjustment chamber boat 4
1.141...-Secondary pressure chamber 41a...-Revised port 42.142...Secondary pressure chamber 43...Pressure receiving chamber 1
36...2nd valve body 145...-1st valve body agent Tsutomu Sadatsu (and 2 others) Figure 2 Water 2 Figure 3 Figure 4 Figure 5/700a Figure 6 (A) ( B) ur flow rate 7th
Figure 8 Figure 9 Decoy Exhaust Figure 10 Figure 11 Figure 12 Device

Claims (1)

[Claims] 1. Used in a pneumatic circuit for operating a pneumatic cylinder,
In a pressure reducing valve with a pneumatic relief that reduces secondary pressure to a constant pressure lower than the primary pressure, a piston equipped with an adjustment spring that biases a diaphragm that receives the secondary pressure toward the pressure receiving chamber is mounted on the back of the diaphragm. The piston is moved to change the biasing force of the adjustment spring in conjunction with the operation of the pneumatic circuit, which is slidably provided in the pressure chamber and switches between passing and blocking air in the pressure reducing valve. A pressure reducing valve with relief for pneumatic pressure, characterized by being equipped with a switching mechanism that switches flow rate and secondary pressure characteristics. 2 Used in pneumatic circuits that operate pneumatic cylinders,
In a pressure reducing valve with a pneumatic relief that reduces secondary pressure to a constant pressure lower than the primary pressure, a piston equipped with an adjustment spring that biases a diaphragm that receives the secondary pressure toward the pressure receiving chamber is mounted on the back of the diaphragm. When the pneumatic circuit, which is slidably provided in the pressure chamber and switches between passing through and blocking air in the pressure reducing valve, is operated, the piston is moved to change the biasing force of the adjustment spring, thereby adjusting the flow rate of the pressure reducing valve.・Equipped with a switching mechanism that switches the secondary pressure characteristics, and a mechanism that increases the flow rate from the primary pressure side to the secondary pressure side to raise the secondary pressure when the secondary pressure is lower than the set pressure, and a mechanism that increases the secondary pressure, and the secondary pressure is set. 1. A pressure reducing valve with relief for pneumatic pressure, characterized in that a mechanism for reducing the secondary pressure by increasing the flow rate from the secondary pressure side to the atmosphere side when the pressure is higher than the air pressure is provided separately.