JPS5831486B2 - compound valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a composite valve having a pressure compensation function and for forming a simultaneously operated pressure fluid circuit.

Conventionally, this type of compound valve was shown in Fig.
No. 40381).

This composite valve has meter-in type pressure compensation valves 20', 20'/(hereinafter referred to as compensation pressure compensation valves) on the discharge side of the pump 40'.

), and a spool-type directional control valve 1'. 1" (hereinafter referred to as directional control valve).

) are connected in series as shown in Figure 1.
', the second valve C1/' is connected in parallel to the pressure fluid source 40', and the circuit 6 a' to the first valve C1 and the second valve Cf is connected in parallel to the pressure fluid source 40'.
A bleed-off type pressure compensation valve 31' (hereinafter referred to as a main pressure compensation valve) is connected to the circuit 7' where s6b' branches.

) are connected to the compensation pressure compensating valves 20' and 2σ'.
Spring chamber 20 a/.

Tank 8 is connected to tank 20b' by directional control valves 1' and 1''.
' and actuator 14', 14! A pilot circuit 8a'tab' is connected to the circuit on the supply side of the main pressure compensation valve 31' via a shuttle valve 12'. This is a configuration that connects to.

In the pressure fluid circuit using this composite valve, when both the directional control valves 1' and 1'' are operated, the actuator 14
', 1e are connected to circuit 1' and circuit 6a'.

6b', compensation pressure compensation valves 20', 2'', and directional switching valve l/
.

1", the discharge pressure fluid of the pump 4σ is supplied, and the other is connected to the tank via directional valves 1', 1".

At the same time, the pilot circuits 8 a' and 8 b' are also connected to the supply side circuits of the actuators 14' and 14'', so the load pressure of the actuators 14' and 1e acts on the pilot circuits 8 a' and 8 b'. However, the high pressure side of this load pressure is selected by the shuttle valve 12' and acts on the spring chamber 31a' of the main pressure compensation valve 31'.

Therefore, the main pressure compensation valve 31' adjusts the fluid pressure in the circuit 7' to
The load pressure of the actuators 14', 14'' is maintained at a value higher than the load pressure on the high pressure side by a certain value.

Therefore, the circuits 6a' and 6b' are controlled to have the same pressure as the circuit 7, but the spring chamber 20a' of the compensating pressure compensating valve 20' and 2σ'
.

The load pressure of each of the actuators 14' and 1e is introduced and acts on each of the pilot circuits 8a and 1e through the pilot circuits 8a and 8bl.
The compensating pressure compensating valve 20' (or 20'') to which the load pressure on the low pressure side of a' and 8 b' acts throttles the upstream side of the directional control valve 1' (or 1/'), and the actuator 14' (
Alternatively, the pressure is maintained at a value higher than the load pressure of 14" by a certain value.

Therefore, the first valve CI' and the second valve C1'' are the directional control valve 1.
The pressure fluid is supplied to the actuator 14' at a flow rate corresponding to the manipulated variable of ', 1''.

14″.

The composite valve having this configuration can supply pressure fluid to the actuator at a flow rate corresponding to the operation amount of the directional switching valve only when both the main pressure compensation valve and the supplementary pressure compensation valve operate together.

The compensating pressure compensation valve is operated by the pressure difference between the upstream pressure and the downstream pressure (load pressure) of the directional control valve, so the upstream and downstream pressure of the restriction formed by the operation of the directional control valve is If the pressure difference between the two sides is operated to a very small value, the compensating pressure compensation valve will no longer control the pressure on the upstream side of the directional control valve.

(The operation of the compensating pressure compensation valve stops.) Therefore, the first valve and the second valve are connected to the pump in the same way as a normal parallel circuit, and the discharge pressure fluid of the pump is controlled by the smaller load. There is a problem in that the entire amount is supplied to the acting actuator, and the other actuator stops, making it impossible to operate multiple actuators at the same time.

The present invention controls the fluid pressure downstream of the throttle formed by the directional control valve to a value corresponding to the maximum load pressure, and maintains the upstream fluid pressure higher than the downstream fluid pressure by a certain value. The technical problem is to enable simultaneous operation of the directional control valve regardless of the amount of operation.

The technical means of the present invention for solving this technical problem includes: an inner hole into which the spool valve is slidably fitted; a load passage to which the actuator is connected to the inner hole; and a supply passage connected to a pressure fluid source. As the spool valve moves, a first bridge passage connected to the load passage and a second bridge passage connected to the supply passage through a restriction formed by the spool valve are opened, and a pilot passage branched from the first bridge passage is opened. The pilot passage has a pilot chamber connected to the first bridge passage and the second bridge passage by using a high pressure selection device, and the fluid pressure in the passage is adjusted according to the fluid pressure in the pilot chamber. directional valves with piloted sequence valves controlling the value are connected to a source of pressure fluid between the supply passage of the directional valves and the source of pressure fluid, connected to form a simultaneous circuit; A pressure chamber and a spring chamber connected to the second bridge passage of the directional control valve and having a spring stretched thereon are arranged at positions facing each other with a valve body interposed therebetween, and the valve body reduces the pressing force between the pressure chamber and the spring chamber. A restriction is formed between the pressure fluid source and the tank or the supply passage according to the difference in the pressing force, and the restriction causes the fluid pressure in the supply passage to be applied to the actuator connected to the directional control valve. A pressure compensation valve is installed to control the pressure to a value that is a certain value higher than the value that corresponds to the maximum load that is applied.

According to this technical means, the fluid pressure in the second bridge passage is controlled by the pilot sequence valve to a value corresponding to the maximum load pressure among the load pressures, and the pressure compensation valve is controlled in accordance with the fluid pressure in the second bridge passage. Since the fluid pressure in the supply passage is maintained, simultaneous operation is possible even if the directional control valve is operated greatly and the pressure difference between the upstream side and the downstream side of the throttle becomes a small value.

The pressure compensation valve mentioned above may be a bleed-off type, a meter-in type, or a branch type pressure compensation valve.

Hereinafter, FIG. 2 showing an embodiment of the present invention will be described.

The directional control valves 1a and lb have the same configuration, and as will be described in detail later, the pressure compensating valve 2 is connected to the pressure fluid source 3.
The pressure fluid flowing in through the actuators 5a, 5
It has a configuration for supplying and discharging to b.

The directional control valve 1a has the same structure as the directional control valve 1a, so its structure is indicated by the same number as the directional control valve 1a with a suffix "b" as required.

) a body 10a having a plurality of internal passages;
The spool valve 12a is slidably fitted into the inner hole 11a of the spool valve 12a and has a plurality of land portions and a small diameter portion.

In the main body 10a, load passages 13a and 14 are provided in the inner hole 11a and connected to the actuator 5a via a pipe line 6at7a.
a, a supply passage 15a connected to the pressure fluid source 3, and a first passage located between the load passages 13a, 14a and the supply passage 15a.
A bridge passage 16a, a second bridge passage 17a, and a discharge passage 18a connected to the tank 8.

Each of 19a is opened.

The spool valve 12a has a land portion 20a that is slidably fitted into the inner hole 11a.

21a, 22a, 23a, and a small diameter portion 24a.

It has tapered portions 25a, 26a and tapered portions 27a, 28a.

This spool valve 12a is located at the illustrated position (hereinafter referred to as a neutral position).

), and the land portions 20a, 23a, 21a, 2
2a is the load passage 13a, 14a and the discharge passage 18a, 1
9a, first bridge passage 16a, second bridge passage 1
7a and the supply passage 15a.

The spool valve 12a is moved leftward from the neutral position (hereinafter referred to as the first switching position).

) and the small diameter portion 24a. 26a connects the load passage 13a and the discharge passage 18a, and the load passage 14a and the first bridge passage 16a, respectively.

, at this time, the tapered portion 27a of the spool 12a is
A throttle is formed between the bridge passage 17a and the supply passage 15a in accordance with the amount of movement of the spool 12a.

Also, move the spool valve 12a to the right (hereinafter, the second
This is referred to as the switching position.

) and the small diameter portions 24a and 26a are the load passage 14a, the discharge passage 19a, the first bridge passage 16a, and the load passage 13a.
Connect each with.

At this time, the tapered portion 28a is connected to the second bridge passage 17a.
A throttle is formed between the supply passage 15a and the supply passage 15a according to the amount of movement of the spool 12a.

A groove 29a provided in the land portion 22a is provided in the main body 10a so that a pilot passage 30a opening into the inner hole 11a is communicated with the tank 8 when the spool valve 12a is in the neutral position and is blocked in other positions. It is formed.

In addition, the first and second bridge passages 16a, 16b, 17a,
Pilot passages 31a, 31b and 42 branch off from 17b.

The pilot type sequence valve 33a is a valve body that abuts a valve seat 34a provided between the first and second bridge passages 16a and 17a, forms a pilot chamber 35a with a spring 36a tensioned therein, and receives the tension of the spring 36a. 37a.

The pilot chamber 35a of the pilot type sequence valves 33a and 33b.

35b is connected to either pilot passage 31a or 31b via pilot passage 39 and selection device 38.

The selection device 38 has input sides 38a, 38b to which the pilot passages 31a, 31b are connected, and an output side 38c to which the pilot passage 39 is connected.
b, whichever has the higher fluid pressure, is connected to the pilot passage 39.

Therefore, the pilot type sequence valve 33a. 33b connects the spool valves 12a and 12b of the directional control valve 1ay1b to the first
, whichever of the fluid pressures in the first bridge passages 16a, 16b that is applied when operated to the second switching position is higher.
It acts on the pilot chambers 35a, 35b to reduce the fluid pressure in the second bridge passages 17a, 17b to the pilot chamber 35a.
, 35b and the springs 36a, 36.
It has the function of adding the pressing force of b.

The relief valve 40 is provided between the pilot passage 39 and the tank 8 and limits the fluid pressure in the pilot passage 39 to be lower than the maximum discharge fluid pressure of the pressure fluid source 3.

That is, the relief valve 40 is connected to the actuators 5a, 5
b is operating, the fluid pressure in the pilot chambers 35a, 35b of the pilot type sequence valves 33a, 33b is limited to the design regulation value even if one or both of these actuators reaches the stroke end. This acts as a safety valve that limits the fluid pressure discharged from the pressure fluid source 3.

Moreover, the actuator 5a. 5b, even if a large load is applied to one of the actuators to the extent that the movement of the actuator is stopped, the pilot chambers 3 of the pilot type sequence valves 33a and 33b
It has the function of limiting the fluid pressure within 5a and 35b to operate other actuators.

The pressure compensation valve 2 is disposed between the pressure fluid source 3 and the supply passage 15b of the directional control valve 1b, and includes a valve body 43 and an inner hole 44 into which the valve body 43 is slidably fitted. is forming.

The inner hole 44 includes a first annular groove 45 in which the pressure fluid source 3 and the supply passage 15b of the directional control valve 1b open, and a second annular groove 46 communicating with the tank 8. 44
The pressure chamber 4 on which the fluid pressure in the supply passage 15b acts via the passage 47 that is always open to the first annular groove 45
8 and the second bridge passage 17a of the directional control valves 1a and 1b.
, 17b are connected to the pilot passage 42, forming a spring chamber 50 equipped with a spring 49 that constantly presses the valve body 43 in the right direction.

The valve body 43 of the pressure compensating valve 2 receives a rightward pressing force due to both the pressing force due to the fluid pressure in the spring chamber 50 and the pressing force due to the tension of the spring 49, and a leftward pressing force due to the fluid pressure in the pressure chamber 48. When receiving a pressing force and the pressing force in the left direction is strong, the first
, to connect the second annular grooves 45, 46.

The operation of this embodiment having the above configuration will be described.

When the directional control valves 1a, 1b are placed in the neutral position and pressure fluid is supplied from the pressure fluid source 3 to the supply passages 15a, 15b, the supply passages 15a, 15b are connected to the spool valves 12a, 1.
2b land portions 21a, 21b.

22a and 22b, so the supply passage 15
The fluid pressure in a, 15b increases and acts on the pressure chamber 48 of the pressure compensation valve 2.

Further, the pressure fluid in the second bridge passages 17a, 17b is the same as the pressure fluid in the pilot type sequence valves 33a, 33b, the pilot passages 31a, 31b, the selection device 38.
, the discharge passage 19a via the pilot passage 39.30a.
, 19b into the tank 8, the pressure becomes almost the same as that of the first bridge passages 16a and 16b.

Therefore, the fluid pressure in the spring chamber 50 is reduced by the spring 36a of the pilot sequence valves 33a and 33b.

The value corresponds to the pressing force of 36b and the passage resistance of the pilot passage.

Therefore, the pressure compensation valve 20 valve body 43 moves to the left to connect the discharge side of the pressure fluid source 3 to the tank 8 .

Next, the spool valves 12a, 12 of the directional control valves 1a, lb
When b begins to move toward the first switching position, the first bridge passages 16a, 16b are connected to the load passages 14a, 14b, and the supply passages 15a, 15b are connected to the second bridge passage 17a.

17b is the tapered portion 27a, 27b is the inner hole 11a.

11b.

First bridge passages 16a, 16b and load passages 14a, 1
4b, the first bridge passages 16a, 16b
The fluid pressure within the actuators 5a, 5b has a value corresponding to the load acting on the actuators 5a, 5b.

This fluid pressure acts on the high pressure selection device 38 via the pilot passages 31a, 31b, and the high pressure selection device 38 connects the pilot passage with the higher fluid pressure in the pilot passages 31a, 3Ib to the pilot passage 39. .

Now, temporarily, the pilot passage 31a is the pilot passage 39.
Suppose you connect to

(It is assumed that the load acting on the actuator 5a is greater than the load acting on the actuator 5b.

) Then, the fluid pressure in the pilot chambers 35a, 35b of the pilot type sequence valves 33a, 33b becomes a value corresponding to the load acting on the actuator 5a, so the second
The values in the bridge passages 17a, 17b also rise to the above values, and the fluid pressure in the spring chamber 50 of the pressure compensation valve 2 also increases.
Same value as above (second bridge passage 17a).

The value of the fluid pressure in 17b.

)become. Therefore, the valve body 43 of the pressure compensating valve 2 moves to the right in opposition to the pressing force due to the fluid pressure within the pressure chamber 48, narrowing the space between the first and second annular grooves.

Therefore, the supply passage 15a. Although the fluid pressure in 15b also increases, this fluid pressure is caused by the passage 4 of the valve body 43 of the pressure compensation valve 2
7 to the pressure chamber 48, and the valve body 43 to the spring chamber 50.
It is pressed against the fluid pressure inside and the pressing force by the spring 49.

As a result, the valve body 43 moves according to the difference between the pressing force from the direction of the spring chamber 50 and the pressing force from the direction of the pressure chamber 48, thereby controlling the fluid pressure in the supply passages 15a and 15b.

That is, the pressure compensation valve 2 controls the fluid pressure in the supply passages 15a, 15b to a pressure higher than the pressure corresponding to the load on the actuator 5a by the tension of the spring 49 in the spring chamber 50.

The pressure fluid flowing into the supply passage 15a of the directional control valve 1a flows through the second bridge passage 17a,
Fluid flows into the actuator 5a via the first bridge passage 16a and the load passage 14a, and discharge fluid from the actuator 5a flows out into the tank 8 via the load passage 13a and the discharge passage 18a.

At this time, the operating speed of the actuator 5a has a value corresponding to the amount of constriction formed by the tapered portion 27a.

The pressure fluid flowing into the supply passage 15b of the directional control valve 1b flows into the second bridge passage 17 approximately corresponding to the throttle amount formed by the land portion 22b according to the amount of movement of the spool valve 12b.
b, flows into the actuator 5b via the first bridge passage 16b and the load passage 14b.

At this time, the operating speed of the actuator 5b is
The value is approximately equivalent to the amount of aperture formed by 2b.

In this way, the actuators 5a and 5b operate, but if a load to the extent that causes the actuator 5a to stop its operation is applied during this operation, the IJ-IJ valve 40 is operated, and the pressure fluid source 3 is activated. Stop the increase in discharge fluid pressure.

Further, in this case, although the actuator 5a stops, the fluid pressure in the pilot chambers 35a, 35b of the sequence type pilot valves 33a, 33b increases only to the set pressure of the relief valve 40, so the actuator 5b continues to operate.

In the above explanation, the load acting on the actuator 5a is
Although the case where the load is greater than the load acting on the actuator 5b has been described, even if the magnitude relationship of the load acting on each actuator 5a, 5b is reversed, the same operation as described above will occur.

As explained above, the present invention uses a directional valve having a pilot type sequence valve and a pressure compensation valve to control the actuator regardless of the load conditions acting on the actuator (in response to the amount of operation of the directional valve). This has the effect of increasing the operating speed.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional technique, and FIG. 2 is a circuit diagram showing an embodiment of the present invention. 1a, 1b...Directional switching valve, 2...Pressure compensation valve, 3...Pressure fluid source, 5a, 5b
...Actuator, 8...Tank,
10a, 10b...Main body, 11a, 1
lb...-inner hole, 12a, 12b-spool valve, 13a, 13b, 14a, 14b...load passage,
15a, 15b... Supply passage, 16a. 16b...First bridge passage, 17a, 17b
...Second bridge passage, 18a, 18b, 19
a. 19b...--Discharge passage, 31a, 31b...
...Pilot passage, 33a, 33b...Pilot type sequence valve, 38...Selection device,
39...Pilot passage.

Claims (1)

[Claims] 1: an inner hole into which the spool valve is slidably fitted; a load passageway to which the actuator is connected; a supply passageway connected to a pressure fluid source; a first bridge passageway connected to the load passageway by movement of the spool valve; Each of the second bridge passages connected to the supply passage through a throttle formed by the spool valve is open and has a pilot passage branching from the first bridge passage, and the first bridge passage and the second bridge passage are connected to each other. A directional control valve including a pilot chamber between which the pilot passage is connected via a high pressure selection device and a pilot type sequence valve that controls the fluid pressure in the passage to a value corresponding to the fluid pressure in the pilot chamber, a pressure chamber connected to the pressure fluid source and connected to the second bridge passage of the directional valve, connected to form a simultaneous operating circuit, between the supply passage of the directional valve and the pressure fluid source; A spring chamber in which a pressure fluid is stretched is disposed at a position facing each other via a valve body, and this valve body is actuated by the difference in the pressing force between the pressure chamber and the spring chamber, and the pressure fluid source is connected to the tank or supply passage. A restriction is formed in between in accordance with the difference in the pressing force, and this restriction increases the fluid pressure in the supply passage to a value that is a certain value higher than the value corresponding to the maximum load acting on the actuator connected to the directional control valve. A compound valve equipped with a pressure compensation valve to control the pressure.